FOU, Alm.del - 2008-09 - Bilag 198: DIIS Report: "MARSKALSTAVEN, Der er ikke nogen bombe, der var ikke nogen bombe, og de ledte ikke efter nogen bombe"

DIIS REPORT 2009:18� Copenhagen 2009Danish Institute for International Studies, DIISStrandgade 56, DK-1401 Copenhagen, DenmarkPh: +45 32 69 87 87Fax: +45 32 69 87 00E-mail: [email protected]Web: www.diis.dkCover Design: Anine KristensenLayout: Allan Lind JørgensenCover photo: The Star III submersible in front of ScrippsInstitution of Oceanography, University of California,San Diego. The submersible was used for eleven divesin Thule in August 1968. GNU Free DocumentationLicense.Printed in Denmark by Vesterkopi ASISBN 978-87-7605-331-4Price: DKK 50.00 (VAT included)Website of the report: www.diis.dk/thuleaccident withpictures, free download and order form for hardcopies.Dansk kolofon på side 128

Why this report?In a letter dated 6 January 2009, the Danish foreign minister, Per Stig Møller, askedDIIS to draw up a report based on the documentary evidence concerning the 1968crash of a B-52 bomber a few miles from Thule Air Base in northwestern Greenland.The B-52 had four hydrogen bombs on board. For more than four decades, the oﬃcialAmerican and Danish explanations have consistently stated that all four nuclearweapons were destroyed in the accident.The foreign minister’s initiative was caused by a debate in the Parliament (Folketing)over some programmes and articles carried by the BBC on November 10 and 11,2008. Seven years earlier, in 2001, the BBC journalist Gordon Corera had received348 documents on the Thule accident from the US Department of Energy’s (DOE)archival facility in Las Vegas.Gordon Corera is a security correspondent for BBC News. He covers counter-terrorism, counter-proliferation and international security issues for BBC TV, Radioand Online. He has written extensively on the British and American intelligencecommunity and has worked as a foreign aﬀairs reporter for Britain’sTodayshow.He is the author of a very good article, ‘The Need for Context: The Complexitiesof Foreign Reporting’. An Old Gower, he continued his education at Oxford andHarvard universities and joined the BBC in 1997. This set of circumstances lookedpromising: a journalist with excellent training and experience, 348 documents, andseven years of reﬂection and research.Unfortunately, the result did not quite live up to expectations. It is fair to ask whether,in Corera’s view, the historical ‘truth’ is conﬁned exclusively to English languagesources. The main assertions in the article were that only three of the four nuclearweapons on board the B-52 could be accounted for, thus leaving open the possibilitythat there was still a nuclear weapon on the bottom of the sea in the bay outsideThule, and that the Americans had withheld information about the real purpose ofa bottom survey done by a submersible in the summer of 1968, namely that it waslooking for the parts of a nuclear weapon.The ﬁrst assertion about the bomb was old news that had been presented in Danishmedia since 1987 and in a new version in 2000. The 2000 version was based on7

documents that had been declassiﬁed in May 1988, together with another documentdeclassiﬁed in November 1995. The second assertion about information havingbeen withheld concerning the true meaning of the bottom survey could be callednew news as far as extensive media coverage is concerned, but it was based on anold, well-known document that was declassiﬁed in February 1991 and was amongthe collection of 317 documents mentioned below. There is no evidence that Corerahas been working in the Danish archives or that he has tried to verify or nuance hisassertion that Denmark was kept in the dark about the purpose of the underwateroperation.The foreign minister’s speciﬁc question to DIIS was whether the 348 documents(or approximately 2,000 pages) obtained by Corera in 2001 contained decisivenew information as compared with 317 documents declassiﬁed by the Departmentof Energy (DOE) from 1986 onwards and released as announced by DOE on 15September 1994. The Thule Radiation Victims Association had requested access to thedocuments, which were also handed over to the Danish government at its request.The 317 documents of the 1994 release also form part of the 2001 release of 348documents with only some variation. Although the 348 collection does contain afew important documents not found in the 317 collection, none of them have beenused in Corera reports or articles. To elaborate a little, the assertions concerningthe bomb in the BBC articles and programmes are identical with claims made bythe Thule Workers’ Association in August 2000, which were widely circulated inthe Danish and international media at the time, for instance, in the Danish dailyJyllands-Postenfor 12 August 2000 (J-P 12.8.2000), and by the BBC on 13 August2000 (BBC News 13.8.2000).BBC Radio World Service even went one step further by claiming that: ‘A BBCinvestigation … has for the ﬁrst time proved that rumours of a lost bomb are true’(BBC World 2008). No small feat. ‘All his geese are swans’, as the saying goes. BBCTwo’s Newsnight was on the same track, explaining that ‘The US abandoned anuclear weapon beneath the ice in northern Greenland following a crash in 1968, aBBC investigation has found’ (BBC Two 2008).Allegations about a ‘missing bomb’ have a long history. For instance, in December1987 Danish media reports raised the question once again. The Danish foreignminister explained that the U.S. Air Force had never rejected the possibility thatparts of one or several bombs could have fallen through the ice, but that it was beyond8

doubt that the four bombs had been destroyed in the crash. He added that the seabottom surveys performed in August 1968 by the submersible Star III had producedaircraft debris but no bombs.Closely interwoven with that topic has been the plutonium balance sheet, that isthe balance between the amounts of plutonium in the bombs and the plutoniumthat was dispersed as a result of the accident. In September 1988, the Danish primeminister answered questions in Parliament on this issue.The similarity of the assertions about one of the bombs is not surprising, given thatthey rest upon nearly identical documentary evidence. In both 2000 and 2008, themedia were using almost the same documents and were interpreting a limited andidentical number of passages in a few of the 348 documents.It should be mentioned, though, that there was one signiﬁcant diﬀerence. In the 2008BBC reports, a number of US oﬃcials or scientists who dealt with the aftermath of theaccident back in 1968 had been tracked down by the BBC journalist and apparentlyconﬁrmed some of the documentary information.One was William H. Chambers, a former deputy associate director and nuclearweapons designer at the Los Alamos National Laboratory, who once ran a teamdealing with accidents, including the Thule crash (see doc. 107026 for a glimpse ofhis role). ‘There was disappointment in what you might call a failure to return allof the components,’ he told the BBC, explaining the logic behind the decision toabandon the search. ‘It would be very diﬃcult for anyone else to recover classiﬁedpieces if we couldn’t ﬁnd them’ (BBC News 2008; BBC Two 2008).According to Chambers, the view was that no one else would be able to ﬁnd thesesensitive items covertly and that the radioactive material would dissolve in sucha large body of water, making it harmless. The BBC article also states that otheroﬃcials who have seen classiﬁed ﬁles on the accident conﬁrmed that a weapon wasabandoned. The Pentagon declined to comment on the investigation, referring toprevious oﬃcial studies of the incident.This account raises some questions. The article claims that unnamed sources have‘conﬁrmed the abandonment of a weapon’. The latter may, of course, be a faithfulquotation of what the unnamed sources have said, but their evidence does not conﬁrmwhat Chambers had said, since the two accounts are speaking of diﬀerent things,9

Chambers about ‘components’ and ‘classiﬁed pieces’, the anonymous sources about‘a weapon’.One can also surmise that Chambers may have had diﬀerent scenarios in mind, onein which the active material was preserved in one piece, and another in which thematerial had been split into particles or fragments.It seems reasonable to suggest that Chambers was holding two possibilities open inhis statement, the ﬁrst being that the ‘classiﬁed pieces’ were intact but had not beenfound, the second that they had been split into particles or had crumbled and werenon-existent as ‘pieces’. To repeat, what the anonymous sources ‘conﬁrm’ in apparentlysaying that ‘a weapon had been abandoned’ does not provide conﬁrmation of whatChambers had said, but constitutes a separate and less concrete form of testimony.The BBC article continues: ‘But the crash, clear-up and mystery of the lost bomb havecontinued to haunt those involved at the time − and those who live in the regionnow − with continued concerns over the environmental and health impact of theevents of that day in 1968.’ Whatever the intention behind this concluding remark,it might easily be read as anargumentum ad misericordiammeant to support thetwo sensational main assertions.We have no idea why it took the BBC journalist seven years to produce his programmeand articles after he had received the batch of 348 documents from DOE. Whateverthe reason, there is no trace in his articles that it was the study of these documentsthat kept him busy for so long. The most interesting thing about his account is notwhat it says about Thule, but that once this under-researched story had been aired, itwas spread to thousands of media worldwide in a matter of hours. You name them,they all have it – from the Rachel Maddow Show to Tageszeitung to Bogotá: ‘EstadosUnidos abandonó un arma nuclear debajo del hielo, en el norte de Groenlandia, araíz de un accidente aéreo ocurrido en 1968, como demostró una investigación dela BBC.’In the New York Times ﬂagship blog Lede, one of the staﬀ correspondents, assistantto the editor of the New York Times, Carla Baranauckas, who received her M.S. atColumbia’s Graduate School of Journalism, cited the Chambers interview as follows:‘He said that there was disappointment when the search was called oﬀ, but that theassumption at the time was that if the United States couldn’t ﬁnd that H-bomb, noone else would be able to ﬁnd it either.’ Chambers had not said a word about a bomb.10

Nuclear proliferation had ﬁnally reached the editorial oﬃces of the New York Times− perhaps a new target for IAEA inspections.Lede’s unoﬃcial motto comes from T.S. Eliot: ‘Immature poets imitate; mature poetssteal; bad poets deface what they take, and good poets make it into something better,or at least something diﬀerent.’ The reader might speculate whether it would be alogical fallacy to conclude that Ms. Baranauckas is a good poet.In the midst of the international media blitz, only Hans M. Kristensen, a projectdirector with the Federation of American Scientists, took a diﬀerent line, telling theItalian channel Panorama that the documents he had seen showed that the fourthbomb had been destroyed like the three others [‘Le carte che ho potuto studiare iodicevano che anche la quarta bomba andò distrutta, come le altre tre’] (Kristensen2008).In a way, this summary is already close to providing an answer to the foreign minister’squestion. No new assertions about a missing bomb were made in 2008, and thedocumentary evidence was much the same as that released by DOE in 1994, whichhas been available in Copenhagen since then and was also used in the Jyllands-Posten’s2000 article. On this basis, one could argue that there would be nothing to add tothe answers provided by the Danish and American authorities in 1995 and 2000.Close, but not close enough to provide a fair answer to the minister’s question. Anysuch reading of the minister’s letter would be highly formalistic. The primary reasonfor this is that an impartial professional analysis of the documents has never beenundertaken. In the absence of such an analysis, it would seem useful to provide atleast some elements of an impartial analysis of the released documents and thus bein a position to comment on the oﬃcial explanations and the assumptions presentedin the media in, for instance, 1987, 1988, 2000 and 2008.It may come as a surprise to many that no such impartial professional analysis wasever undertaken. Probably, the explanation is that the focus on matters related toThule and the US presence there has changed over the years. At one time, the focuswas the dislocation of the Uummannaq settlement in 1953 in connection with theconstruction of an air defence system for the base, then it was health physics andradiation associated with the 1968 accident, and ﬁnally the international relationsaspects of Thule Air Force Base as epitomized by the so-called H.C. Hansen documentof 1957 (Hansen was the Danish prime minister at the time).11

The latter story has been dealt with in a major two-volume study undertakenin 1996-97 by the Danish Institute of International Aﬀairs (DUPI). Amongmany other things, it covers the prehistory and political aftermath of the 1968accident. However, DUPI was not tasked with undertaking studies of what hadhappened to the bombs. A ﬁfty-page English summary of the 1997 DUPI Reportis available: ‘Greenland during the Cold War: Danish and American SecurityPolicy 1945-68’.At least since the turn of the millennium, and indeed for longer than that, the focushas been on questions of radiation and health physics. For the moment, this appearsto be a relevant and desirable research priority.

What DIIS can doDIIS can conduct historical research on the basis of the available documents, subjectthem to analytical examination and try to extract evidence from them when theyappear to be silent, or when particular words, lines or paragraphs have been declaredexempt from declassiﬁcation and have accordingly been erased or obliterated by thereleasing agency.To our knowledge, this is the ﬁrst time that these documents have been subjected tosystematic examination by a historian having the fate of the weapons as the researchfocus. As already mentioned, the DUPI Report of 1997 had no such focus and wasbased on a quite diﬀerent collection of sources procured by DUPI itself from a widerange of U.S. and Danish archives. That report mainly covered the preceding years,and as far as the 1968 events are concerned, it dealt almost exclusively with thediplomatic aftermath of the crash.This Danish research eﬀort was clearly reﬂected at a later stage in Vol. XII of ForeignRelations of the United States, 1964-1968 (FRUS). The FRUS series presents theoﬃcial documentary historical record of major U.S. foreign-policy decisions andsigniﬁcant diplomatic activity. The series, produced by the State Department’sOﬃce of the Historian, began in 1861 and now comprises more than 350 individualvolumes.DIIS can do what historians are trained to do, namely try to reconstruct and understanda chain of events in the past. However, DIIS cannot investigate the documents withthe eyes of engineers, physicists, medical doctors or similar professionals.12

Some initial observationsAs already mentioned, all down the years since 1968, the oﬃcial version of whathappened to the four nuclear weapons has been that they were destroyed in the crash.On several counts, the released documents seem to support the oﬃcial explanationat ﬁrst glance.For instance, in an early report of 27 January 1968 – only six days after the crash– the SAC Disaster Control Team reported that ‘based on the serially numberedcomponents found to date, there is convincing evidence that at least three separateWH [warhead] H.E. [high explosives] detonated high order on or above the surfaceof the ice. This conclusion is based on the location of the four weapon parapacks[packs with parachutes for the weapons], three tritium bottles, and portions ofthree separate weapon secondaries’ (doc. 107132). This document was declassiﬁedas early as 1988.We have chosen this early quotation on purpose in order not to take the suspensecompletely out of the narrative of the present investigation. It still leaves room forsome doubt as to the fate of the fourth bomb.This initial observation, however, will not distract us from the main task. Asexplained below, our purpose in this report is to undertake an impartial assessmentof the events on the basis of the released documents. With this in mind, we willkeep the door open for any explanations that can reasonably be supported by thedocuments.

We will do our best to establish the nature of the excised parts of the documents inorder to try and provide a coherent picture of the reason the deletions were made.We are not convinced that it will be possible to provide deﬁnitive answers to thequestions that have attracted the interest of the public on the basis of sanitizeddocuments. Nonetheless, we hope that even some less deﬁnitive reﬂections on thesequestions may prove to be of some value. If we are able to accomplish any more, thatwould be a pleasant surprise.Before we turn to the detailed investigation, it should be mentioned that some of thebasic facts about the aircraft, the bombs, the site, the sea bottom and the submersibleare presented in fact boxes in the appendices.Furthermore, a spreadsheet with basic data regarding all 348 documents in thecollection is available for download on the DIIS website. It contains excerpts fromsome of the documents, and those documents that we have found to be of specialinterest for the purposes of this report have been colour coded. The documents canbe sorted in various ways: by author/issuing agency, by date of issue, in some caseseven by hour and minute, by date of declassiﬁcation etc. On the website, a collectionof photographs from the dives of the American submersible Star III in Bylot Soundoutside Thule can also be found.

Based on the assumption that the interpretation of what happened to the nuclearweapons is likely to have changed during the long search and clean-up operation,we will conduct a chronologically organized analysis of some of the key documents.This will serve as a simple ﬁrst layer of protection against the confusion that couldeasily result from reading the documents haphazardly.We also hope that a chronologically ordered survey will lead to insights into thedevelopment of the thinking of those involved in the operation in Thule.After the chronological analysis, we will look for analogies by making a short excursionto the Palomares accident of 1966, which involved the same type of aircraft andweapons as in Thule two years later. Palomares is a coastal village in southeasternSpain.We will then sum up what we have learned about the recovered weapons parts andprovide some additional information and analysis from other sources. Next, we willrecapitulate those observations that may be of relevance for the plutonium balancesheet.The reader is therefore invited to join us on a short excursion through the sanitizeddocuments in order to see whether they contain more information than has beenthought up to now. Unfortunately, the many deletions in the documents have theinevitable consequence that quite a few conjectures will be necessary in the courseof the analysis, for which we ask the reader’s indulgence. We could have spent severalmonths longer trying to solve the puzzles in the sanitized documents, but that wouldhave meant taxing the readers’ patience even more than we have done already.Having collected the bits and pieces together, we will ﬁnally assess the evidence in asystematic manner and then present the conclusions of the report.The scope of the report is limited in the sense that it is primarily based on the 348collection, that is, U.S. documents that in many cases have been declassiﬁed for nearlytwo decades, but in addition a few documents from Danish and other archives willbe considered. The report does, however, beneﬁt from the few documents that arenew in the 348 collection as compared to the 317 collection, as well as to a lesser15

degree some of the documents in a collection handed over to the Danish governmentin 1988 and declassiﬁed in 1994.Finally, a few remarks on terminology might be in place. The words ‘deletion’ and‘excision’ are used interchangeably. A ‘sanitized’ document is one in which someparts have been ‘deleted’ or ‘excised’, represented by black bars or white holes inthe remaining text. ‘Redacted’ is another word in the jargon for ‘sanitized’. A‘partially redacted’ document can be found to be ‘releasable’. The deleted parts canbe characterized as ‘withheld’ or ‘exempt from declassiﬁcation’. The same happensto whole documents that can then be represented in the publicly accessible archivefolders by a ‘withdrawal sheet’ loosely identifying the ‘withheld’ document.Just because a document is ‘declassiﬁed’ does not mean it is automatically accessible.First it has to undergo a ‘release’ process that can involve reviewing information onthe basis of privacy, law enforcement, and other considerations. As a more generalremark, not aimed at any speciﬁc countries, some classiﬁed documents may becompletely hidden for the historian’s eye in document collections that he will noteven suspect exist or in archive holdings with outlandish names that have beendeliberately chosen to mask their real contents.

The documents in the collection are highly repetitious, as they reﬂect the diﬀerentphases of communication between a large number of agents and agencies in thebureaucratic chain of command. In this sense, the documents are like a nest ofChinese boxes. The starting point of much of the subsequent correspondence wouldbe General Hunziker’s Strategic Air Command (SAC) Disaster Control Team, whichafter the accident was ﬂown in to Thule on short notice from SAC Headquarters inOmaha, Nebraska.Mobilization after the accident involved personnel from the Danish authorities andover 70 U.S. agencies, including elements of the Department of Defense, AtomicEnergy Commission (AEC), State Department, Los Alamos Scientiﬁc Laboratoryand Lawrence Radiation Laboratory. Reports and briefs were regularly prepared forthe Chief and Vice Chief of Staﬀ of the Air Force (CSAF), CINC SAC, the Secretaryof the Air Force, the Joint Chiefs of Staﬀ (JCS), and the Secretary of Defense.Some of the best and clearest summaries of the information sent forward in thechain of command were written by the oﬃce of Brigadier General Edward B.Giller, Director of the Department of Military Applications in the Atomic EnergyCommission. His memoranda were sent to the chairman and commissioners of theAEC. The chairman was the chemist, Glenn Theodore Seaborg, who had shared a1951 Nobel Prize for the discovery of plutonium in 1941.To begin with, we will devote the ﬁrst pages of the chronological survey to somemicroanalysis of the documents that cover roughly the ﬁrst ten days after the accident.This is the period in which the most signiﬁcant weapon ﬁnds are concentrated.We should not expect this to add signiﬁcantly to what is already known about theaccident, but nonetheless it may provide some insights into the nature of the secrecysurrounding the event, the sorts of information the excisions are intended to hide,the comprehensiveness of the security reviews, and the eﬀectiveness or ineﬀectivenessof the exemptions and excisions in guarding these supposed secrets.Later in the chronological survey, we will focus on groups of documents dealingwith speciﬁc aspects of the operation, such as the recovery of ﬁssile material fromthe secondaries, the underwater operation, and discussions among decision-makersin Copenhagen and Washington.17

22 January 1968, doc. 107145This document is a status report for the accident in the form of a memorandum fromBrigadier General Edward B. Giller, head of the Department for Military Applications(DMA) at the United States Atomic Energy Commission (AEC), to the Chairmanof the AEC, Seaborg, and his commissioners. The document was declassiﬁed in 1988and is identical with document 75943 apart from a diﬀerence in redaction.Giller wrote ten such status reports over the period up to 10 September 1968.Generally, Giller’s status reports give a convenient overview of the events as theyunfolded in the United States and Greenland. They are easier to work with thanthe many scattered telegrams.This is the ﬁrst day after the crash. The memorandum states that there have beenno reports of any explosions resulting from the accident, and the evaluation wasthat the weapons had remained ﬁxed to the bomb racks and sunk with the fuselage.However, at the time of reporting, the location and condition of the four weaponswas still unknown.

Taking into consideration the darkness and the cold, one can hardly expect the ﬁrstreports about the accident to be precise. In fact, this report was already contradictedthe next day. Still, what the document conveys seems to be that no detonations ofthe high explosive in the weapons had been sighted or heard, and that the authorwas already aware at this time that a hole had been made in the ice.In the duplicate version of the document, doc. 75943, which had been declassiﬁedtwo years earlier, in 1986, the ﬁrst three and a half lines of the last paragraph ofthe above quote have been excised. This is the ﬁrst but not the last inconsistency ofredaction that we will ﬁnd in the documents.18

Ahead of the last paragraph, one or two lines have been deleted in both redactions. Thefuller of the two versions allows us to surmise that these lines contain a description ofthe four thermonuclear weapons, known to have been of type Mark 28, the same asin the accident two years earlier in Palomares, on the southeastern coast of Spain.23 January, 1968, doc. 107144A preliminary report from the SAC Disaster Control Team has a list of weapons,fuses and chutes involved (with the precise identiﬁcations deleted). It also states thatthere were indications that one or more weapons went high explosive (HE) highorder, as well as that parts might have gone right through the ice.The idea of a HE high-order detonation may reﬂect the fact, that in this early phaseof the search, perhaps none or only very few parts of the weapons had been found.At this point, a high-order detonation plus a hole in the ice might be one way ofexplaining the possibly meagre results of the initial searches for weapon debris.On January 25, at a meeting in the Danish Atomic Energy Commission in Strandgadein Copenhagen, Dr Carl Walske, Assistant to the Secretary of Defense for AtomicEnergy, gave his version of what was known about the bombs at this early stage.According to the Danish minutes, he said that ‘it was possible that the high explosivesin one or more of the weapons had detonated. […] Available information indicated thatone of the bombs had detonated and that this had led to plutonium contamination.[…] None of the four bombs had been found, but the four parapacks that are fastenedto the bombs had all been found. […] Three of the parachutes showed no signs ofexplosion or ﬁre, while one which had been found approximately 300 metres fromthe impact point (the others were closer) had clear marks of ﬁre or explosion.’‘Thus, one could deduce that one bomb had been damaged, while the three otherswere possibly intact on the ice, in the ice or on the sea bottom; the possibility thatone or more of the latter bombs had been damaged as well could not be ruled out;pieces of metal, maybe from a bomb, had been found near the impact point.’ (AEK26/1 1968).25 January 1968, doc. 107138A telegram from the SAC Disaster Control Team raises a number of questions, amongthem: ‘If some weapon components are on the bottom of the bay at approximately625 feet of water, how can they be detected and removed?’19

25 January 1968, doc. 107139The SAC Disaster Control Team stated its belief that an underwater eﬀort mightbe required. However, on the very day of the report and the next day weapons partsbegan to be recovered on the surface, and ideas about an underwater search weretemporarily laid aside for the more pressing needs of the surface operation.26 January, 1968, doc. 107137The clip below is from a cable sent by the SAC Disaster Control Team about itsoperations on January 25.We learn that ‘two objects, approx 24 inches (61 cm) long and 10 inches (25 cm) wide,located 2 and 1 slant 2 miles south southwest of impact point and approximately 300yards (275 m) apart, have been tentatively identiﬁed’. The whole paragraph is apparentlyabout weapon components. We learn from other documents that the two objects hadbeen tentatively identiﬁed as secondary cases and that they had not been identiﬁedwith any speciﬁc weapon (doc. 107121). Since they were identical in size and had beenfound 300 yards apart, we can assume that they are from diﬀerent weapons.

We may ask what ‘tentatively identiﬁed’ means. This is hidden by the excision. Doesthis indicate doubt as to what type of object it was? Or does it mean that the serialnumbers were not visible or maybe had been damaged and were hard to read? Maybenot the former, if we assume that the two objects were parts of secondaries. If so, theywould probably be recognizable from their shape. It is signiﬁcant that the locationindicated is consistent with the locations of secondary parts on a sketch of the crashsite to be presented later (Chapter 5).We have therefore already disclosed the identity of the ﬁnds. If we thought thatthis would remain hidden from us, we were mistaken. Because of inconsistent20

redacting, the identity of the objects is revealed in, for instance, doc. 107132 of27 January, which summarises the ﬁnds of the previous days (see below), while afew days later, in doc. 107121, we are given the answers to some of our conjecturesonce again (see below under 30 January). Furthermore, in his report #4, doc.107128, CSAF says that these ﬁnds are signiﬁcant.Two badly deformed T bottles were also found on this occasion. T bottles aresometimes called ‘reservoirs’ in the documents. They are containers that holdtritium, which is used to boost the yield in the primary stage of a nuclear weapon.The fact that they were found separated from other parts of the weapons is yetanother clear indication that some of the weapons had broken up. For ease ofmaintenance, the reservoirs are placed at the tail end of the bomb, outside thephysics package.Finally there is the deleted part after ‘… less valves’. This half line hardly containsinformation about the location of the T bottles. It is not likely that such informationshould be excised when it is not concealed two lines earlier. That leaves us with twooptions. Either something else is missing, or something else was found togetherwith the bottles, and was presumably identiﬁed by serial number alongside the Tbottles.The excised part might also contain a qualiﬁcation about the valves of thetritium bottles, since a valve is mentioned in a subsequent memorandum,doc. 107121. We cannot know. Still, if something else was found, we can saywith near certainty that the excised part is not about parapacks. Parapacksare mentioned in several other documents, and information about them isnot kept classiﬁed.27 January 1968, doc. 107130In his report #3 to JCS, CSAF provides information about newly recoveredweapon parts, litra a. through h. We have moved one step up the bureaucraticladder where CSAF is summarizing and commenting on the ﬁnds that havealready been reported by the SAC Disaster Control Team. The parts in litraa., f. and g. have been deleted from the list, but we learn what they are from acomparison with other documents. These are probably the more interesting ﬁnds.That, at least, is what CSAF thinks since the next day in report #4 he calls them‘signiﬁcant ﬁnds’.

The ensemble of recovered parts now leads CSAF to inform JCS that all weapons arethought to have broken-up to varying degrees. Furthermore, evidence so far tendsto indicate a low-order high explosive (HE) detonation [words deleted], but no ﬁrmconclusions have been drawn.We are now on day 5 after the accident, and a somewhat more precise pictureof the fate of the weapons begins to emerge, although ﬁrm conclusions cannotbe drawn. In contrast to doc. 107144 of 23 January, the investigators now ﬁndindications of low-order rather than high-order explosions of the high explosive(HE) in the weapons (cf. fact box). Because of the deleted words, we cannot besure whether this assessment covers all the weapons or only some of them. Thewording ‘evidence so far tended to indicate’ may well mean that only some of theweapons were covered.The high explosives mentioned here are the HE charges in the primary parts of theweapons. We have only one source for the amount of HE in each of the primaries,which says it was 250 kg (Notits 5/2 1968). Whether this amount is correct we donot know.Anyway, one ton of HE, together with more than 100 tonnes of jet fuel, would seemto go a long way in explaining the total degree of destruction of the aircraft. ProfessorKofoed-Hansen reported that the aircraft had been shattered into millions of piecesacross an area of 5-10 square kilometres (Notits 5/2 1968).22

The wording ‘broken up to varying degrees’, taken together with only a ‘low order’detonation in the primaries, could indicate that some larger portions of the secondaryparts of the weapons had been found on the ice, together with smaller parts as well(107130).If we assume that a high-order detonation would do more damage to the secondariesthan a low-order detonation of maybe only some of the HE charges in the primaries,the reason for the changed assessment of the character of the HE detonation mightbe that some relatively well-preserved components of the secondaries had been foundon the ice since the ﬁrst assessment. Obviously, recovery of some of the other piecesmay also have supported the new assessment.Nothing is said about ﬁnds of primaries or primary parts. Instead we learn about theirfate in the wording ‘low-order’ detonation. The suspected low-order detonation inthe primaries would explain the ‘omission’ of any mentioning of primaries, as theremay not have been any vital pieces of primaries to report about, at least at the timethis report was written.The primaries with the HE were more exposed to destruction than the secondaries.Nowhere in the documents have we observed any discussion of the possibility thatsome weapons could have gone high order while others went low order. Perhapsone should keep open the possibility that the bomb with serial number SN 78252had gone high order and thus been more badly damaged than the three otherweapons.The type of contamination on the site may have provided the investigators with anotherclue for their assessment. They knew the composition of the pit in the primary, whichcontained both highly enriched uranium and plutonium. They also knew the stateand mass of the secondaries found up to the time of writing the report. We supposethat the secondaries contained no plutonium, only uranium. Substantial amounts ofthe uranium from the secondaries were recovered during the clean-up operation. Wewill return to the question of the composition of the ﬁssile core of the secondariesin our survey of the February operations, as well as later on.27 January 1968, doc. 107132Additional weapon components were found on 26 January. A cable from the SACDisaster Control Team speaks with a higher degree of certainty than the precedingdocument. It states that, ‘based on the serial numbers of the found components,23

there is convincing evidence that at least three separate warheads HE detonated highorder. […] This conclusion is based on the location of the four weapon parapacks(parachute packages), three tritium bottles and portions of three separate weaponsecondaries.’ (107132). With these words, the discussion of low versus high orderexplosions was apparently settled in favour of high order, and the speculations onthe basis of the preceding doc. 107130 may seem to have been in vain.The ﬁrst part of the clipping reports the ﬁnds of 25 January. It follows that the excisedpart is about the two secondary cases found 2 and 1 slant 2 miles S-SW of impactpoint and characterized as signiﬁcant ﬁnds by CSAF (107128).The second part summarizes the ﬁnds of 26 January. What do the excised linesrepresent here? From the document itself we learn that the ﬁnds were portions ofsecondaries. CSAF, in his report #4 the next day, tells us that the ﬁnd consists offour more serially numbered weapons parts.In the last paragraph of the clipping there is one deleted word. We suggest that theword ‘segment’ could be hidden behind the black bar. The segment took up most ofthe space in the secondaries.In other words, no parts had yet been identiﬁed with the fourth secondary. Thiswas mentioned again in Giller’s third status report of 2 February (doc. 318366,declassiﬁed in November 1995) and fourth status report of 23 February (doc. 318356,declassiﬁed in November 1995).

It should be noted that the present document, 107132, which mentions that noparts of the fourth secondary had been found in the early phase of the search, hadalready been declassiﬁed in 1988, more than 20 years ago. Thus, the diﬃculty ofaccounting for the secondary stage proper of the fourth weapon can hardly comeas a surprise today.The oﬃcial explanations could be considered somewhat stronger on the basis ofthe circumstantial evidence of the document. It is therefore appropriate to ask, ifthree bombs had apparently fared so badly, why not the fourth as well? This seemsthe most likely explanation. On the other hand, the document contains no traceof the fourth secondary. It might have disappeared undamaged through the holein the ice. If that could be proved or made plausible, it would seriously underminethe oﬃcial explanations.27 January 1968, doc. 107133This cable from CSAF to the SAC Disaster Control Team contains the answer tothe question raised on 25 January about underwater operations. The most promisingmethod for underwater reconnaissance, detection and the removal of objects wouldbe the Navy’s Curv Diving System. Curv had a radius of action of 500 to 600 feetat a depth of 600 to 700 feet when operated from a tether point on the surface25

Based solely on the serial numbers on the components found to date, thedocument says that ‘there is convincing evidence that [deleted] weaponsdetonated on or above the surface of the ice’. If this were all the informationwe had it would not be much, but what we have here is not impenetrablesecretiveness, but rather an example of inconsistent redaction. In document107132 above we have just seen what is behind the black bars in 107128:four parapacks, three tritium bottles and parts of three separate weaponsecondaries.Ironically, the secretive 107128 with its excessive excisions was declassiﬁed threeyears after the more transparent 107132.28 January 1968, doc. 107129In his report #5 of 28 January 1968, afternoon, CSAF informs JCS regardingconﬁrmation that several weapons had been found. The excision means that wecannot know how many weapons had been found by then – meaning parts ofweapons − only that not all four had been found. But again this is a result ofinconsistent redaction. In document 107132 we have already seen what is hiddenbehind the black curtain: four parapacks, three tritium bottles and parts of threeseparate weapon secondaries.27

29 January 1968, doc. 107125In report #6 from the SAC Disaster Control Team, we learn about the recovery ofmore weapon parts. A whole paragraph is excised at the beginning of the document.Judging from its sheer size, and of course the fact that it has been deleted, thisparagraph may contain a description of important weapon components. Two otherdescriptions of found parts have been excised as well.It has only been two days since the Disaster Control Team sent the report containedin doc. 107132. There are many indications that this report is mainly a recapitulationand maybe also a speciﬁcation of what had been reported earlier. At the same time, itcontains information about an apparently signiﬁcant ﬁnd made on 28 January. Wesurmise that the main excised paragraph at the beginning deals with this new ﬁnd,and again with the four parapacks, three tritium bottles and parts of three separateweapon secondaries. We have not discovered whether the new ﬁnd of 28 Januaryis the relatively intact secondary that we learn about in Giller’s memorandum of 2February (doc. 318366), or whether it is the fourth tritium bottle (reservoir), whichwe know was taken back to the U.S. with the ﬁrst shipment of recovered weaponparts on February 2.

Behind the black line after the words ‘closing plate,’ we probably have something like‘a portion of a weapon case 4 by 6 inches’. The one line that has been excised a littlefurther down in the document is probably about ‘weapon parts and debris’. Theseconjectures are based on document 107132.30 January 1968, doc. 107120CSAF informs JCS about further weapons recovery on January 28. The descriptionof one or more weapons parts is excised. This document sends report #6 of the SACDisaster Control Team one step up the chain of command. As noted earlier, theexcision may conceal the ﬁnd of a relatively intact secondary.

30 January 1968, doc. 107121This internal memorandum of the AEC summarises what was known to the AECas of the afternoon of January 26. The documents from these days are basically a setof nested Chinese boxes with a lot of repetition. In the memorandum we learn moreabout the two objects found on January 25 and mentioned above under January26 in doc. 107137. In the clipping below, they are said to have been ‘tentativelyidentiﬁed as secondary cases’ but ‘have not been identiﬁed with any speciﬁc weapon’.However, nothing is said about any content of the cases. Are they empty shells, or29

One of the parachutes ‘was in a hole in the ice which measured approximately 30inches in diameter and which apparently had been caused by something burninginto the ice. The water in the hole had refrozen at a level 12 inches lower than theoriginal ice level. It was not known whether the object causing the hole had goneall the way through the ice and into the water.’ See sketch of the Thule debris ﬁeldshowing locations of major weapon components. The sketch shows the locations ofthe parachutes, close to the burned area and the impact point (Chapter 5).Furthermore, the memorandum mentions cracks in the ice 100 yards north of the burnedarea: ‘Ice in that area was badly fractured and had been badly churned up.’ Some ofthe cracks were up to four feet wide. It was not known ‘whether the ice was fracturedby the impact of the aircraft or by the subsequent explosion.’ At the time of writing,the parachutes had ‘not been identiﬁed with any speciﬁc weapon or weapons.’

that the ice at the north end of the streak had been freshly frozen and that theblocks of ice had been upended and refrozen in abnormal positions. Photographsof the crash site revealed a circular pattern of fracture lines about 600 feet indiameter and a smaller circular area of ice that had been more severely disturbed(see photograph in the appendix of basic crash data. H.D. Bruner’s trip report,doc. 107118). Later, Wright H. Langham convincingly argued that the explosions,not the crash, were responsible for the fractured ice (107038). Again, this may bean indication of the destructive consequences of the explosions for the nuclearweapons as well.30 January 1968, doc. 107123This internal note within the military division of the AEC describes one of theobvious purposes of operation Crested Ice – to recover enough weapon parts ‘toassure [sic] that security of Restricted Data and responsibilities for nuclear safetyhave been adequately covered.’Care was taken that the team of Danish scientists did not obtain access to classiﬁedinformation about the weapons. General Hunziker ordered a large room to be setaside for use by the Danish scientists. This kept them out of the classiﬁed traﬃcpattern, although they had full access to general Hunziker and his staﬀ at all times(doc. 107118).This same consideration is evidently – and not surprisingly − making itself felttoday in the sense that it is reﬂected in the classiﬁcation policies regulating accessto documents on the accident.

It should be noted that, in a report on his trip to Thule from 23 January to 3 February1968 (doc. 107118), H.D. Bruner writes that the plutonium of the weapons hadbeen oxidized and aerosolized by the explosion. This reminds us that, as long as wedo not have access to more comprehensive lists of the ﬁnds, we cannot completelywrite oﬀ the possibility that some tiny fragments of the primary pits might havebeen found.Bruner was one of the important ﬁgures in the operation. He was assistant directorfor Medical and Health Research in the Division of Biology and Medicine of theAEC.1 February 1968, doc. 106969Again a recovered warhead is mentioned. Strictly speaking, the excision preventsus from knowing whether we have a complete warhead here or only components ofone. We cannot even know for sure whether the term as it is used here designatesthe whole nuclear weapon or only parts of it. There is hardly any doubt, though,that what we have here is the best preserved of the warheads, a relatively intactsecondary, also mentioned in Giller’s report of 2 February and possibly found on28 January.The ﬁnd of a relatively intact secondary means that this particular weaponwas destroyed. Both the primary stage and the tail end of the weapon weremissing.

2 February 1968, doc. 106961This is the third of the useful status reports from Brigadier General Giller. The ideathat something important could be hidden by the above excision would seem to besupported by the fact that this four-page memo for the AEC and its chairman wasdeﬁned as not declassiﬁable and removed from the archive folder in 1988. The memois represented in the 348 batch only by an administrative reference sheet.The reader should not despair, though: consolation is around the corner. Sevenyears later, in another declassiﬁcation round, a copy of the same document wasdeclassiﬁed and is represented in our collection as document 318366. We willcome back to that soon. Thus, withholding doc. 106961 could perhaps be said torepresent a reﬂection of the less than perfect nature of human bureaucracy ratherthan of secretiveness. As it turns out in document 318366, the document saysnearly nothing that we have not heard before in the other reports from 27 Januaryonwards. Thus, there is hardly any reason why doc. 106961 should be exempt fromdeclassiﬁcation.2 February, 1968, doc. 106962This is the seventh report on the recovery operation from the SAC DisasterControl Team. It does not give us much information apart from some news aboutthe parachutes. However, several paragraphs have been excised, and the documentthus serves as a ﬁrst-rate example of how much classiﬁed information some of thesereports contain.The excisions are so comprehensive that it would appear futile to speculate abouttheir content. The best strategy at this point in our investigation seems to be to waitfor a later summary of the recovered weapon parts.As always, when the excisions are comprehensive, our ﬁrst guess will be that somethingimportant has been found.On a methodological note, and using this document as an example, one could saythat it is probably more important to count these ‘excised dogs that don’t bark’ butwhose shadows we can see than it is to be too occupied with what is clearly visible,in this case the parachutes.And then again, the above remark is in fact an exaggeration. We do more or lessknow what is in the excised paragraphs, or at least we think we know. It can hardly33

We are informed that ‘the ﬁrst batch of weapons [more than one line deleted]’ willarrive at Andrews AFB on February 3. The excision conceals from us any detailedknowledge of the character of this shipment, but we will learn a little more in thenext document.The fact that the shipment took place on a plane which was used by someimportant American oﬃcials was most likely a trivial matter of practical logistics.Furthermore, we learn that this was only the ﬁrst batch. This could mean that aconsiderable amount of weapons components had been found already at this stageof the operation.One of the components in the shipment was certainly the nearly intact secondary.Other items in the cargo were four recovered tritium reservoirs, one of them in aparticularly bad shape.2 February 1968, doc. 318366This is the document that we think is identical with the non-declassiﬁable document106961 of the same date mentioned above. Such inconsistencies in classiﬁcation anddeclassiﬁcation are quite normal for historians working in archives. Somewhat toour surprise, exactly the same has happened with doc. 107004, which was withheldas not declassiﬁable but is in fact represented in the collection by the very importantdoc. 317871, which was declassiﬁed in April 1995 and thus not available in the 317collection.Even more surprising, doc. 104810 of 22 April, about an underwater search for weaponsdebris at Thule, is still withheld in the collection, though it is in fact representedby the only slightly excised document 107036, which was declassiﬁed in May 1988,only a few months after the decision to withhold doc. 104810.Given the vast number of documents involved in the declassiﬁcation process, suchapparent inconsistencies are bound to appear quite often. Furthermore, inadvertent35

releases of restricted data and formerly restricted data are so frequent that DOE sendsannual reports to Congress about them. Obviously, what has happened in the ﬁrstof these cases is that the two identical documents have been handled in diﬀerentsecurity reviews separated by seven years.Such things happen all the time and are perfectly understandable: it would beextremely costly to avoid them. But we must admit that it is hard to suppress asmile when we read the U.S. response of September 1995 to nine Danish questionsof 22 March 1995. One of the questions was whether the above-mentioned doc.106961 could be provided to the Danish authorities – if need be, on a privilegedbasis.The U.S. response was that the documents that had been completely withheld hadbeen ‘retrieved and re-examined in order to verify that the information withheld,either national security information or restricted data, was still classiﬁed properly.This was a comprehensive review conducted with an eye towards release. All of theinformation withheld during the ﬁrst review was conﬁrmed to still require protectionunder the Atomic Energy Act or other security guidance. To reveal this informationwould jeopardize U.S. security interests and violate U.S. policy to prevent theproliferation of nuclear weapons.’Ironically, an excised version of the requested document was released soon after the‘ﬁnal response’. It is hard to avoid a sarcastic observation that the situation couldnot have changed in two months. Perhaps the declassiﬁcation of 318366 was an actof diplomatic courtesy by an American oﬃcial. In that case we should not suppressour smile but simply smile – and, before we forget it, kindly ask our Americancolleagues to put the withheld document 106961 back in the folder. Not that thiswould provide any new information, but these unnecessarily withheld documentsnonetheless foment vague suspicions.As just mentioned, the U.S. government had stated that the information withheldrequired protection under the Atomic Energy Act or other security guidance, andthat to reveal this information would jeopardize U.S. security interests and violateU.S. policy to prevent the proliferation of nuclear weapons. We readily subscribe tothe principle of guarding state and private secrets and, more often than is usuallyassumed, the guardians of the secrets and the historians can be said to serve thesame general public interest, each from their own angle. In general, this is ouroverall evaluation of the present collection of documents.36

That said, this idyllic picture does not hold true in all instances. In this case we haveseen quite a number of examples where documents have been withheld erroneouslyand redactions of documents have been inconsistent. The whole business of secrecy,with its withheld documents, excisions and deleted words, becomes a hornets’ nestin which intermingling interests are hard to reconcile.For the bureaucratic mind the language of the original U.S. decision may seem aneﬀective way of closing a case, but it is also liable to make the hair stand in the caseof those readers who are worried about the hidden health hazards or environmentalconsequences. They will start to think that something very, very suspicious is hiddenbehind the veil of secrecy.It is easy to understand how such deﬁciencies occur, but the tone of imperial infallibilityused in defence of a human and error-prone system of secrecy and declassiﬁcationdeserves a little editing as well.That said, the many cases of inconsistent redaction are to some extent an indicatorof considerable openness. When many documents are released, the task of keepingtrack of diﬀerent redactions of the same or similar information in copies of the samedocument spread over diﬀerent archival holdings and even diﬀerent countries, as wellas of documents that cite each other, sometimes at long intervals and not necessarilywith adequate references, can quickly become extremely complicated and hit thesecurity reviewers like a tsunami.When thinking about lifting a single black line in a document the security reviewer mayeasily feel overwhelmed by considering the repercussions this might have for scores ofother documents. Faced with the workload this might imply as well as the risk of errors,the easy way out for the security reviewer is to uphold the existing classiﬁcation.There is generally no reason why historians should feel deceived and adopt anunforgiving attitude towards the archivists, who, with a view to openness, arestriving to make information accessible and at the same time guard both private andpublic secrets. Only when secrecy is used as a veil to hide unwarranted, erroneousor lenient habits of declassiﬁcation will there be clashes of interest between thehistorians and the archivists.Bringing these meandering considerations to a conclusion, we should perhaps remindourselves that nuclear accidents of this kind are not an everyday event. Contaminating37

the territory of other states with plutonium is the exception rather than the rule.Thule and Palomares are two examples of this.The half-life of plutonium is roughly 24,000 years. In 1995, the U.S. called itsanswers to the questions of the Danish government a ‘ﬁnal response’. Yet, giventhe extraordinary character of the event and of the contaminant involved, therecan hardly be any ﬁnal answers or time limits. For good order, it should be notedthat theFinal Response to Danish Questions on B-52 Crashdeclared that theAmerican authorities ‘remained prepared to address additional inquiries shouldthey pertain to new aspects of the 1968 crash’ (Final Response 1995).What the U.S. has done to remedy the situation is good: for example, the removal ofcontaminated ice, snow and debris. What the U.S. could reasonably do more or dobetter but has not done is bad. It is not a question that depends on this generationalone or that can be settled once and for all. New knowledge and the evolution ofnorms can change perceptions, interpretations and priorities.Some of the secrecy surrounding certain aspects of these events may be the mainsource of worry and speculation among those who have been most directly aﬀectedby the accident, namely the inhabitants of the Thule area. In this light it is disturbingthat the security review of the American documents pertaining to the accident wasclearly not carried out ﬂawlessly, nor, indeed, given adequate attention by the U.S.Government. It is embarrassing that unnecessarily withheld documents are allowedto feed unfounded suspicions.A declassiﬁcation review of the documents pertaining to the accident cannot beperformed as a routine matter according to standard procedures such as appears tohave been the case in this instance. In essence, it must take the form of a researchproject within the responsible U.S. agencies with the necessary investment of timeand expertise to do the security review and the declassiﬁcation properly. We cannottell what that would take, but it should not be a huge project. But until the veil ofsecrecy can be completely lifted, high priority could be given to declassiﬁcation reviewsat regular intervals with the objective of eliminating all obsolete or unnecessaryclassiﬁcation requirements.In a recent Presidential Memorandum, President Barack Obama declared thathis administration is committed to operating with an unprecedented level ofopenness concerning classiﬁed information and controlled unclassiﬁed information38

(Obama 2009). Furthermore, with our topic in mind, it is noteworthy that theSecretary of Energy, Steven Chu, reiterated and endorsed the President’s Freedomof Information Act policy in a memorandum sent to senior Energy Departmentoﬃcials on 5 June 2009 (Chu 2009).As far as we know, there is no need for the U.S. side to take into account Danishsecurity regulations or political sensitivities in this matter. On the Danish side,documents from 1968 concerning the Thule accident are available in the archives.This applies, for instance, to the holdings of the Ministry of Foreign Aﬀairs, theDanish Atomic Energy Commission and Risø National Laboratory. In a varietyof ways, Danish authorities and research institutions are doing their part, forexample, through regular monitoring of the plutonium levels in the area, on landas well as on the sea bottom. International research consortiums have contributedto this eﬀort as well.We understand from the literature that general knowledge of the eﬀects andcharacteristics of plutonium contamination, as well as the concrete analysis andinterpretation of monitoring data, will beneﬁt when more precise information onthe so-called sources of the ﬁssile material involved in the accident can be released.This could be a favourable outcome, both locally and globally, for the quality ofcontemporary monitoring and for preparedness in case of future accidents orattacks with so-called dirty bombs (Vantine and Crites 2002).We now return to doc. 318366. In this third high-level memorandum fromGeneral Giller of the Division of Military Applications (DMA) of the AEC to thechairman of the AEC and its commissioners, the shipment in the above documentis mentioned once more. One of the items in the shipment, we now learn, was arelatively intact secondary. Details of the other items in the shipment have beendeleted in this document in the same way as in the preceding document 106963.The short excision below, after the words ‘shipment increment’, perhaps simply hides

a few words about parts of two secondaries, but more likely it conceals somethinga bit more interesting than that.At the beginning of the memo, there is a summary of the recovered componentsfound from 27 January up to 2 February. As can be seen from the clipping below, alarge block has been excised. That paragraph can be assumed to contain importantinformation about the found components, possibly speciﬁed to such a degree thatit would reveal ‘restricted data’ about the weapon’s design. We cannot be sure aboutthe full contents of the excision, but at least we would expect it to register the ﬁndsthat were made on 28 January and 1 February.

It is equally important to note that the experts at Thule had been unable to matchall of the recovered secondary parts with speciﬁc weapons. These secondary partscould belong to any of the four weapons and, arguably, most likely to some of thosethree secondaries that had not been recovered in nearly intact condition.Incidentally, Gordon Corera is committing an analytical error in basing hisconclusions about the ﬁnal destiny of one of the weapons on such very earlyand tentative reports. This is why we ﬁnd it useful to review the documents inchronological order.4 February 1968, doc. 106960This report conﬁrms that the aircraft had begun to disintegrate prior to the crash.Pieces of aircraft wreckage, mainly bomb door residue, were found ‘almost two milesnorth of the impact point. These items had zero radiation readings.’

The excisions mean that we cannot be sure that all the recovered parachutes arementioned. The parachutes mentioned in the visible parts of the text maybe only theunidentiﬁed ones, since in earlier documents some of the parachutes are associatedwith speciﬁc weapons. One possibility is that all four recovered tritium reservoirsare mentioned in the deleted parts.Be that as it may, on 19 March, one and a half month later, the parachutes andall four tritium reservoirs had been identiﬁed with a weapon. This concludes themicroanalysis of the ﬁrst few days. Future students with more time at their disposalmay be able to squeeze more information out of these documents and correct someof the mistakes that we may have made here.

Special aspects of the search operations and Danish-U.S.negotiations4 February 1968, doc. 106959Report #10 from CSAF tells us that the State Department representative on theSAC Disaster Control Team believed that Professor Kofoed-Hansen, who by nowhad left Thule for Copenhagen, was bringing with him a personal report that wouldcontain exaggerated estimates of area aﬀected by plutonium. This appraisal did noteven come close − deﬁnitely no cigar.In reality, what happened when Kofoed-Hansen returned to Copenhagen was that heoﬀered a very low estimate of the plutonium contents of each weapon to the AtomicEnergy Commission as compared to what was generally believed at the time. Professor42

Koefoed-Hansen’s estimate was 2 kg of plutonium for each weapon. As we shall seelater, this estimate was a good one. Partly, of course, it was based on the observationsof the Danish scientists in Thule, but it is hard to believe that he should not haveconsidered it conﬁrmed in exchanges with American colleagues in Thule (Notits5/2 1968). Later on, in another document – a report written by the American groupof scientists at Thule – we learn that 2 kg was what the Danish scientists generallybelieved, and that the American scientists agreed to discuss the accident with themon that basis (Crested Ice SAC 1969, Vol. IV, Annex i).5 February 1968, H.H. Koch notatIn a preliminary memorandum, H.H. Koch, Chairman of the Danish Atomic EnergyCommission, wrote that Kofoed-Hansen had returned from Thule via the UnitedStates. On the plane from Thule with the relatively intact secondary in the cargo, hemay have used the opportunity to continue discussions with his American colleagues,Dr Bruner and Dr Langham. Kofoed-Hansen had informed representatives of theCommission, the Ministry for Greenland and the Ministry of Foreign Aﬀairs thateach of the four bombs was thought to contain 2 kg of plutonium.

5 February 1968, doc. 107152 (hand-written), with 106915, 107151and 107160On the same day that Dr Kofoed-Hansen was brieﬁng the Danish authoritiesin Copenhagen, Dr Langham and others were giving a similar presentation inWashington at a DOD-AEC brieﬁng. The documents listed in the heading arethe Chairman’s account of the preliminary views of the Safety Evaluation Panelfor the Thule incident following the DOD-AEC brieﬁng on 5 February 1968.Documents 106915, 107151 and 107160 are type-written and identical except fora few things, one of them being a hand-written note on doc. 107151 shown in theﬁrst clipping below. The type-written accounts are orderly and easy to understand,but we should notice the sentence in the second line: ‘The general substance is notdocumented here except with respect to a few points…’. It follows that we have tolook elsewhere for the substance of the brieﬁng. Where do we ﬁnd that?Before we answer this question, we should take note of another revealing diﬀerencebetween the type-written versions. The Chairman’s account had already beendistributed among the participants of the meeting when the Director of Classiﬁcationof the AEC, Murray M. Nash, discovered that it should be recalled since it contained‘secret restricted data’. Accordingly, along with a letter of 13 February, the security44

oﬃcer of Woods Hole Oceanographic Institution returned their ‘one and only copy’of the Chairman’s account, having already classiﬁed it. The doc. 106915 version ofthe Chairman’s account is the one returned to AEC by Woods Hole.Let us consider the information which had caused the withdrawal of theChairman’s account from Woods Hole: ‘We are told that [hand-written: aminimum of 38%] 38% of the total plutonium burden has been located onthe snow and ice around the site of the crash; 36% of the burden is within theisopleths corresponding to 100,000 counts per minute as measured on theavailable instrumentation.’

At the belated intervention of the Director of Classiﬁcation, this informationwas classiﬁed since it permitted a direct estimate to be made of the amount ofplutonium in the weapons. Accordingly, the whole quotation above was deletedin the 1988 security review of the document. The U.S. Government’s 1995‘Final Response to Denmark’s nine questions’ said that a comprehensive reviewhad been conducted to verify that the information withheld was still classiﬁedproperly. ‘All of the information withheld during the ﬁrst review was conﬁrmedto still require protection.’ This statement covers the excision discussed here.As for the claims of comprehensiveness of this second security review, one canadd that the information withheld in doc. 106915 can be read in full in docs.107151 and 107160.The clipping below is one of the sparkling jewels in the 317 and 348 documentcollections. The reader should take a deep breath. What we have in front of us is asmall piece of the hand-written notes from the meeting. The two lines presented in45

In his presentation, Langham explained how much of the total plutonium burdenhad been located on the snow and ice around the crash site. The two lines read: ‘3.Calculation of Pu [plutonium] in area by grid = at least 38% (?) + 40% (may be upto 54%) total’.What is unique about the hand-written version is that it has three ﬁgures: 38%,+40%, and in parentheses ‘maybe up to 54%’, whereas two of the typewritten versionshave only one ﬁgure, 38% cf. doc. 107151, above, with its hand-written addendumunder ‘38%’ saying ‘a minimum of 38%’, and even this one ﬁgure is deleted in doc.106915, thus telling us exactly which piece of information caused the Director ofClassiﬁcation so much anxiety. Only the hand-written version gives us the completekey to a question that has been discussed ever since the accident took place.Among the radiological survey data at Dr Langham’s disposal for his brieﬁng was athirteen-page report of the initial radiological survey, performed along 30 degree radialsand ready on 1 February 1968 (Walske-Koch 15/4 1968, enclosure 1; Crested Ice SAC1969, Annex B, Appendix III). Also available at this time was the ﬁrst isodose chart(doc. 107148, ﬁgure V). The validity of the 1 February radiological survey was laterconﬁrmed in the twentieth situation report from the SAC Disaster Control Teamof 17 February (doc. 106904), in which the results of a close grid (50 foot interval)radiological survey of the burn area, completed on 14 February (doc. 106906), werediscussed. As far as a historian can judge, the early survey data do not diﬀer in anysubstantial way from later ones. We ﬁnd it fairly safe to proceed on that assumption.The ﬁgures presented in the hand-written version are expressions of the minimum,median and maximum estimates in percentages made for plutonium dispersed on thesnowpack and the ice. For our purpose, it is of no importance whether these estimates46

were precise or not, as long as we know what Langham’s kilogram estimates were atthat particular date. The amounts expressed as percentages of the total plutoniumburden correspond to the minimum, median and maximum estimates of dispersedplutonium in the snowpack and the ice expressed in kilograms. We have used theusual ﬁgures for plutonium on snow and ice: 2.8 kg as the minimum and about 4 kgas the maximum. It is obvious that our argument is dependent on the assumption thatthese were the ﬁgures Langham used. We have checked whether there is roughly thesame relationship between the two sets of ﬁgures 38:54 and 2.8:4, and there is.The total plutonium burden is equal to the content of plutonium in the weapons.Langham had as his ﬁxed value the amount of plutonium in the weapons. He alsoknew the minimum, median and maximum estimates for plutonium in snow and icein kilograms. It follows that it was easy for him to tell the panel the minimum, medianand maximum percentages of the ‘total plutonium burden’ in the ice and snow.Now that we have been told these percentages and are fairly sure that we knowLangham’s other data as well, it is equally easy for us to calculate the total amount ofplutonium originally contained in the weapons before dispersal, which for so manyyears has been the ‘great unknown’, the ‘Mother of All Secrets’, the ‘Holy Grail’.The result is about 7.5 kg.��

For four decades, clearly signalling that they were not compromising secret data, theAmericans have called the ﬁgure of 6 kg an approximate value and a very reasonableestimate, and they have been right. Now, have we really discovered the Mother of AllSecrets? No, of course not. This big secret is simply a sedimentation of past necessities,a dogma, once meaningful, that has gradually become an empty ritual. However, aswith all dogma, it is hard to give it up.By the same token, we have shown once again that the suspicious State Departmentoﬃcial was absolutely wrong in his 4 February report. We have seen that ProfessorKofoed-Hansen’s and Dr Langham’s assessments of the plutonium contained in theweapons and dispersed in the explosions corresponded very well with each other.We are, of course, not leaving the jewel in the crown at that, but will take anotherlook at it in Chapter 5. Suﬃce it to repeat here that this document was released in1994 as part of the 317 collection, that is, before the solemn language of the ‘FinalResponse to Danish Questions’, where the qualities and necessities of the securityreview system were pompously impressed on the slow Danes. It has, in other words,been accessible for ﬁfteen years.8 February 1968, doc. 106940Telex about the handling of four (tritium) bomb reservoirs from Lee Hancock, AECrepresentative, Albuquerque, to G. Stone, DMA, AEC, Washington.The following quotation in the document comes from a Los Alamos message of 7February 1968, which says: ‘Reservoir nos. 1A1-14582-22, 1A1-63685-42, 1A1-63875-42 and 1A1-53057-22 were removed from container nos. JP 65711C9, JP65273C9 and JP 65547C9 during the period February 5-6, 1968.’According to Lee Hancock’s report of 20 February (doc. 106883), the four (tritium)bomb reservoirs had been sent to Los Alamos with the ﬁrst shipment of weapondebris from Thule on 2 February. Like, for instance, a nearly intact secondary,they too had accompanied Kofoed-Hansen, Langham and other scientists on theﬂight back to the U.S. We thus know that all four tritium reservoirs had beenrecovered before 2 February and sent to Los Alamos for further identiﬁcationand measurements.We will comment on the importance of the recovery and identiﬁcation of all fourreservoirs later.48

14-16 February 1968, docs. 106899, 106907, 106908Two days of meetings took place in Copenhagen between Danish and U.S. oﬃcialsand scientists. The extent of the plutonium contamination was discussed and anagreement reached on the modalities of the continued monitoring of the situation,as well as the removal of the contamination on snow and ice. In his summary of thenegotiations, Carl Walske called it a ‘gentlemen’s agreement’.The high-level composition of the negotiating teams and the thoroughness of thediscussions show the considerable care that was devoted to remedying the consequencesof the disaster and the excellent spirit of cooperation between the two teams, whichprevailed in spite of negotiating positions that, at least from the outset, were quite farapart. The negotiations and communications between the two sides are testimonyto a very professional handling of a crisis.24 February 1968, doc. 106887SAC Disaster Control Team report #27.In this document, we follow some of the eﬀorts to locate the remains of ﬁssile andﬁssionable materials in the weapons. The same can be seen in doc. 106893 of 22February. On 6 February, a special eﬀort had been initiated to search for uranium235. This special part of the weapon recovery operation went on for over a monthin this format, but continued all along with other methods until the conclusion ofthe diving operation in August.This proved useful in detecting weapon components buried in snow and ice. Dailysearch activities with PRM5/SPA-3 equipment were continued until weapons searcheﬀorts were reduced in March (Crested Ice SAC 1969, Annex B). This eﬀort is alsomentioned in a telex of 6 February from the SAC Disaster Control Team in Thule,which mentions experiments with the same equipment to locate large sources ofuranium 235 (set at 185 keV) and plutonium (set at 375 keV) (doc. 106954). We haveseen no indication that a search for large sources of plutonium should have yieldedany results. With the amount of information at our disposal, the plutonium part ofthe operation would seem rather hypothetical.These daily activities can be followed to some extent in the documents (Crested IceSAC 1969, Annex B, Appendix I). As mentioned, the measuring instruments usedfor this purpose were the SPA-3 probes, which were set at 185 keV, showing that theteams were searching for the actual uranium 235 of the ﬁssile core, the spark plug, of49

the secondaries. We are told that ‘A 20 pound section [half a line deleted] was found8/10 of a mile south of the burn area.’ That this was not just any piece is shown bythe fact that it was ‘brought on base to thaw for further identiﬁcation, packagingand shipment’ to Los Alamos.Shipping this part to Los Alamos was special treatment, since, in his fourth reportof 23 February (doc. 106891), Giller had stated that all recovered weapons partswere sent to Rocky Flats except for the tritium reservoirs that had been sent to LosAlamos. This is diﬀerent from 30 January, when Pantex seemed to be the preferreddestination for weapons debris (doc. 107123). The roles of Pantex and Rocky Flatsin the handling of weapons parts are mentioned again in a report of 20 February(doc. 106883).This 20-pound section (9 kg) ﬁts with one of the secondary parts on a sketch of theThule debris ﬁeld showing the locations of major weapon components (Chapter 5).We think this 9 kg section contained the ﬁssile core in the secondary of bomb no.1, SN 690020, a pipe of uranium 235 also known as oralloy. A document from theDirectorate of Nuclear Safety says of bomb no. 1 that ‘parts of the secondary werefound 1 mile and 2 miles south of the southern tip of the burn area’ (Broken ArrowThule 1968). This is ﬁne match for the location of the 9 kg section. The matchdepends not only on the location itself, but also on the similar language used in thetwo sources in designating the location.

Supposing that the found section contained a whole ﬁssile core of a secondary,we have learned a few important things: ﬁrst, that 25 percent of ﬁssile materialwas recovered from the secondaries in this ﬁnd; secondly, that the ﬁssile core ofthe secondaries may have weighed about 8-9 kg; thirdly, that these items wereconsidered suﬃciently important to make a targeted eﬀort to recover preciselythese ﬁssile cores and ﬁnally, conﬁrmation that they consisted of uranium 235.Furthermore, we may have acquired a tool for interpreting other documents in thecollection. Of course, we cannot know whether some outer casing was includedin the 20 pounds.5 March 1968, doc. 107007SAC Disaster Control Team report #42.The excised part of the document shown below is probably taking note of therecovery of a pit part which we believe to be a piece of uranium 235/oralloy from asecondary pit, occasionally, we believe, called an ‘oralloy pit’ in order to distinguishit from the primary pit. This observation is based on a comparison with documents107041 (12 April) and 107047 (1 April). The fact that SPA-3 probes are mentionedboth before and after the excised part tells us that we are in the middle of a hunt fororalloy. More will follow about the pit parts. We have not been able to verify thisterminology in reference works or consultations with experts. If it turns out to becorrect, the lexicographers will have some corrections to make.

C.L. Marshall, dated March 6; and an enclosure to the memorandum, ClassiﬁcationBulletin WNP-16, dated February 16.As yet, an example of what appears to be an inconsistent security review doc. 317871is identical with the withheld document 107004. The excised document 317871 wasdeclassiﬁed on 26 April 1995, whereas document 107004 was security-reviewed andwithheld on 18 March 1988.These documents, although still with large excised parts, serve as a perfect illustrationof the dilemmas faced by the U.S. authorities in handling the classiﬁcation issuesraised by the accident.

As the document says, ‘current classiﬁcation rules’ provided that the amount ofplutonium in speciﬁc weapons was ‘Secret Restricted Data’. How many kilograms ofplutonium were there in the primary pits? That was the question, and the secret.This piece of secret information, together with a small number of other design details,was in essence what explained the need to have closed classiﬁed information circuitsduring and after the Thule recovery operation.As we have said before, there is nothing surprising or unusual in this fact. Seen fromthe perspective of the Director of Classiﬁcation, it is easy to imagine his reactionswhen the scrupulously built classiﬁcation system for which he was responsiblesuﬀered the onslaught of such an accident, with all the associated pressures arisingfrom considerations of foreign relations and public diplomacy.This document might deserve a more detailed examination, but let us conﬁne ourselvesto the crux of the matter, which was how much the Danes could be told about thedetails of the released plutonium without giving them the key to the precise ‘SecretRestricted Data’. The logical candidate for the words behind the black bar, the factthat should be ‘eﬀectively concealed’, is the amount of plutonium found on weaponsparts and aircraft debris.52

14 March 1968, doc. 909684Memorandum by W.B. McCool, Secretary of the AEC.The memorandum summarises the decisions taken at information meeting 780 of theAEC on 11 March 1968. Having considered various alternatives, the Commission hadfound a compromise. The method of transmitting the desired information throughthe agreement with NATO had been found not feasible.Instead, the AEC made a statutory decision that ‘(a) the fact that approximately[deleted] 6 kg of plutonium were involved in the Greenland accident, and (b) our bestestimate of the amount of plutonium we have removed from the site of the accidentcould be published without undue risk to the common defence and security.’In taking this statutory declassiﬁcation action, the Commission concluded that thedata should be provided to representatives of the Danish government as ‘privilegedinformation’ with a request that its dissemination be carefully controlled, and thatadministrative measures should be taken to appropriately control its disseminationwithin the United States.This was probably seen by the Danish authorities as a satisfactory compromisewhich, on the one hand, gave them the tools they needed to monitor the ecologicalsituation and the health hazards in the area, while on the other hand taking care ofone of their other aims, which was to avoid unduly alarming the population. This isan important and legitimate aspect of any responsible crisis management.It was a small political victory for Carl Walske to have this piece of informationdeclassiﬁed. He understood, of course, that it would be impossible to have theexact ﬁgure for the plutonium content in the weapons declassiﬁed, and settledfor a rounded-oﬀ value instead. This was, incidentally, suﬃcient for his purpose,which was to give the Danish government a kind of guarantee that there wasno more plutonium in the bombs than it suspected. Carl Walske’s handlingof this matter shows him to be a diligent operator as well as a broadmindedstatesman.

Here again we have a couple of exotic ﬂowers in the jungle of the security reviewers.We have to turn to a later document in the collection, doc. 138077 of 18 June 1968,in order to learn that the deleted words in doc. 909684 are ‘6 kgs.’, although thisinformation is present on the website of the Department of Energy and is part ofthe ‘Final response’ of 1995.Incidentally, the short informal notes from the Danish-U.S. meeting in Washingtonfrom 18-19 March 1968 are also very discreet in this regard and do not mentionwhether the newly declassiﬁed information about ‘approximately 6 kg involved inthe accident’ was actually disclosed to the Danes on this occasion (AEK 18-19/31968).As noted already, the Marshall memorandum of March 8 (AEC 907/28), on whichthe AEC was acting at the meeting on March 11, was withheld as 107004 butdeclassiﬁed as 909684.However, one must take into consideration that there is no absolute coincidencebetween the real world and the world of bureaucratic decision-making when it comesto putting things on paper for the record.In the real world, Danish and American scientists were working and relaxing togetherunder extreme and unusual circumstances, and in some cases they were travelling onthe same airplanes, with plenty of time for Socratic dialogues about plutonium.In the real world, the Danish scientists were remarkably well informed about the HolyGrail, that is, the amount of plutonium in each primary pit. In February, Kofoed-Hansen reported to the Danish Atomic Energy Commission that each weapon wasbelieved to contain 2 kg of plutonium (Notits 5/2 1968).On March 21, another Danish scientist, Asker Aarkrog, noted in his diary andreported in a telegram his impression from a conversation with health physicistJim Olsen that the total amount of plutonium in the weapons might be roughly5-6 kg rather than the 7-8 kg that had been assumed by the Danes (Aarkrogsdagbog).This was ten days after the decision had been made in Washington that the Danescould be informed on a conﬁdential basis that 6 kg of plutonium were involved inthe accident. As we have seen, Dr Walske was the prime mover in supplying the54

relevant ﬁgures to the Danes, and it can be noted that, according to telegrams, hewas in regular contact with Jim Olsen in these days.A report by the U.S. scientiﬁc advisory group at Thule tells us about its deliberationswith the Danish scientiﬁc group. The report conﬁrms that ‘the Danish estimate oftotal active material originally present was about 2 kilograms per weapon or about 8kilograms. We used their ﬁgure in dealings with them.’ The report was classiﬁed secretand declassiﬁed in 1994. It characterizes the Danish scientists as ‘an active and capablegroup’ and ‘obviously a highly talented one’ (Crested Ice SAC 1969, Vol. IV, Annex i).Technically, the Danish group was well equipped to do the job (AEK 29/1 1968).In yet another American document, the impression of a team of competent Danishscientists is conﬁrmed. Doc. 318355, a memorandum for Dr Walske dated 7 February1968 on the problem of radiological contamination in the Thule accident, containeda recommendation that a model should be made of the weapons in the aircraft, thedistribution of weapon and aircraft debris, and the particle size and distribution ofthe plutonium. Walske was informed that Sandia Corporation had made similarmodels in the past, and the memo continued: ‘The Danish team has generated sucha model, and the U.S. counterparts should be similarly provided.’A comparison with what may have been believed in the Swedish Defence ResearchAgency at the time tells us that these Danish estimates were in no way trivial. TheSwedish agency was not very precise in its draft of 14 February 1968, which containedthe proposed answer to be given by the Swedish prime minister to a member ofparliament concerning the contamination in Thule. However, it is most likely thatthe Swedish agency did not want to be precise and was successfully striving to puttogether an answer that could be called a triumph of imprecision.The Swedes had sent their draft to the Danish Atomic Energy Commission in orderto obtain its opinion. The Swedish draft listed uranium 235, uranium 238 andplutonium 239, and continued that it was safe to assume that the total amount ofthese substances did not exceed a few hundred kilograms (‘Den totala mängden avdessa ämnen överstiger med säkerhet ej något hundratal kg.’).In their reply to the Swedish question, H.H. Koch and Jørgen Koch wrote thatplutonium was the relevant substance – which the Swedes of course knew – andthat the amount of that might be somewhere between 10 and 20 kg. H.H. Koch,who had certainly not forgotten the 8 kg reported by Kofoed-Hansen, was probably55

balancing two opposed assessments So as not to let exaggerated ideas of the amount ofactive material be spread in the Swedish public, and not to compromise the classiﬁeddata of an ally (Notits 15/3 1968). We have not checked the actual answer of theSwedish prime minister.We can all imagine how the Danish perception evolved. The Danes obviously obtainedtheir information by a combination of observation and conversation, not by directlycommunicating precise ﬁgures or outright security leaks, but in discussions of thekind where assumptions are aired and counter-assumptions and body language formpart of the communication.Information acquired in this way has two important characteristics: it is useful inassessing situations, but it is also diﬃcult to use in a credible way in any kind offormal public communication because it cannot be corroborated.14 March 1968, doc. 106996This document contains an exchange of letters between Dr Walske and the Directorof Classiﬁcation, Marshall. Walske has got his way and can now inform the Danesabout the amount of plutonium removed by the United States from the site of thecrash and the approximate number of kilograms involved in the accident.The riddle here consists in the fact that Walske writes ‘total kilograms of plutoniumcontained in the four weapons’, after which the next half line is deleted. We can onlytry to guess what he says here. Maybe something like ‘expressed as the approximateamount of 6 kgs. involved in the accident’. Or something about a ‘rounded oﬀ value…’.This is a guess. There are several other possibilities.

As noted before, however, we do believe that Walske was basically sincere and well-meaning in speaking in this passage about the total amount of plutonium containedin the weapons, although the words behind the black bar reveal that the ﬁgure wasgoing to be an approximation or a rounded-oﬀ value, as Walske called it. At the sametime we must admit that we have had to travel a long way before being prepared tobelieve that this ﬁgure is roughly correct.We started out being rather skeptical on this account, thinking that the formula‘involved in the accident’ was an ingenuously invented bureaucratic euphemismintended to hide the real contents of the bombs. Gradually we came to the oppositeconclusion that it is actually an ingenuous euphemism for disclosing the near truthabout the amount of plutonium in the bombs in a format relevant for the Danes atthat time, while simultaneously defending the position that the actual plutoniumcontent of the weapons was restricted data.The question of the plutonium content in the weapons will be taken up again inChapter 5, where we will summarize the evidence from the available sources.13 March 1968, doc. 104813United States Atomic Energy Commission. Memorandum from Edward B. Gillerfor Chairman Seaborg and others. Fifth status report to the Commission [AEC].Chronologically, we are close to the Danish-U.S. meeting of experts in Washington,D.C. which took place on 18-19 March 1968.

The diﬀerence is that the last one and a half lines have been deleted in doc. 104813.We may ask ‘positive identiﬁcation of what’? Of a relevant weapons part, one wouldthink, that had probably been tentatively identiﬁed already. Are we talking aboutthe oralloy part found on 4 March (doc. 107007)?Another remarkable feature of this document is its discussion of the desirability ofand methods for obtaining a material balance for plutonium. Obtaining a materialbalance was considered highly desirable (a) to satisfy AEC’s interest in the amountsthat were to be disposed of; (b) to satisfy AEC’s interest in the long-term health andsafety aspects of the amount of material that was not removed from the incidentsite; and (c) to reassure the Danish government that an adequate clean up had beencompleted. Among the desired activities were measurements for three categories inparticular: liquid, aircraft debris, and weapons scrap.The ﬁnal results of measurement in these three categories have not yet beenprovided to the Danish government. To say the least, the understanding ofthe interests of the Danish government in this regard was more pronounced in1968 than, for instance, in 1988 or 1995. If the U.S. government chose to sendthis information to the Danish government tomorrow, it would still be a quickresponse under the perspective of the 24,000 years of plutonium half-life. Quickresponse is better thanFinal Response to Danish Questions on B-52 Crash(1995).Fortunately, DOE has stated that public input is welcome regarding how theDepartment may release information of legitimate interest to the public (DOE1996; cf. Chu 2009).58

This topic was also touched upon in the following document.15 March 1968, doc. 104812Notes on Thule plutonium, internal memorandum, Division of Operational Safety.As of 13 March, all signiﬁcant weapons debris was ‘thought to have been collectedand sent to Rocky Flats for post-mortem.’ It was requested that ‘the most accurateestimate possible’ should be made of the plutonium quantity in these packages.We do not know the result of the plutonium estimate for the weapons debris. Onewould suspect it to have been higher than for the aircraft debris, in which, so thememorandum says, ‘no appreciable amounts’ of plutonium had been found. MaybeLangham did not agree with that. A few days later, he told a Danish delegation that‘perhaps 5% of the plutonium had been impinged into aircraft parts’ (AEK 18-19/31968). The lack of knowledge concerning the result of the plutonium estimate for theweapons debris negatively inﬂuences contemporary attempts to establish a materialbalance of the plutonium involved in the Thule accident.Walske’s original tactical argument – as we see it – that in order to give the Danes theﬁgure of approximately 6 kg of plutonium it was necessary to conceal the amounts onaircraft and weapons debris hardly applies any more now that we know the ﬁgure of7.5 kg for the contents of the weapons. Under these new circumstances, it would seem abit dogmatic to uphold any ﬁction that no measurements were made of these values.

19 March 1968, doc. 106985This is the sixth status report from Giller to the chairman of the AEC. Unfortunately,according to the security reviewer’s note, the attachments have been withheld. Theywould have given us a good picture of the results of the examination of weapons partsat Rocky Flats up to that moment.The ﬁrst of the missing attachments is a memo from Hancock to Giller dated 13March, 1968. The second missing attachment is a report with the title ‘Evaluationof Thule weapon debris, with enclosures’.Unquestionably, it would have been helpful to have access to ‘Evaluation of Thuleweapon debris, with enclosures’, since this is the main evaluation of the ﬁrst 23shipments or so of weapons components and debris from Thule.However, as we shall see in Chapter 5, a short summary report of the recoveredweapon parts does indeed exist, although it is excised and is not a complete list. Thissummary report is not contained in the present batch of documents from the DOEarchival facility, but it can be found in the Department of Defense reading room onthe internet (Broken Arrow Thule 1968).We are hinting in particular at the very important information contained in thatdocument that an analysis by the AEC of the recovered secondary componentsindicated recovery of 85% of the uranium and 94%, by weight, of three secondaries(Broken Arrow Thule 1968). It would not be surprising if this information couldalso be found in one of the withheld attachments we have just mentioned.However, what is of the utmost importance in this sixth status report is that itsummarises the recovered parts of the fourth weapon, SN 78252. Both the tritiumreservoir and the parachutes had been identiﬁed as belonging to SN 78252. Theywere in a worse condition than the similar items from the other bombs. This mightvery well be an indication that SN 78252 could have been more badly damaged thanthe other weapons. If that was the case, it would not be surprising that it provedimpossible to ﬁnd other identiﬁable parts of this bomb. The fourth tritium reservoirhad been found at the latest before 2 February, when it was sent to Los Alamos withthe ﬁrst shipment of weapons parts (doc. 106883).For the oﬃcial explanation, the reservoir is more important than the parachutes.Already because of the loss of the reservoir, the ‘fourth bomb’, SN 78252 had become60

Identifying these items from the ‘fourth bomb’, SN 78252, as being in a worsecondition than the similar items from the other bombs is an open invitation tohypothesize that, when the Americans were contemplating the possible recoveryof a very well-deﬁned missing weapons component, it would perhaps be from oneof the other secondaries they had found portions of, rather than from SN 78252,which they may have surmised had been completely split up and, to the extent thatit was available at all, perhaps only in tiny unidentiﬁable pieces, and more likelyto have been picked up on the surface of the ice already than to be waiting for thesubmersible on the sea bottom.This consideration of probability can perhaps be supported by a rash conjecturewhich would point at SN 453171 as the more likely candidate for the supply of amissing weapon component.We base this conjecture on the following passage from doc. 107041 of April 12. Aguess would be that the ﬁrst black spot conceals, for instance, the words ‘oralloy’ or‘several’ or a number, while the second black bar may hide the word ‘primary’.

If our assumptions here are correct, the meaning of the paragraph would then be thatsome pieces of uranium 235/oralloy from the secondary pits had been identiﬁed withbombs SN 690020 and SN 815950, but not with SN 453171 or SN 78252, whereasno pieces had been identiﬁed as being from the primary pits.In trying to interpret this, the ﬁrst thing we should remember is that uranium 235was present in the primary pits in higher quantities than plutonium. There is alsosome likelihood that at least some of the uranium and plutonium in the primarypits would have integrated to some degree either in the production process or inthe explosions. If such pieces had been found, it would not have been diﬃcult todistinguish them from pieces of pure uranium 235 coming from the secondary pits,especially since it seems reasonable to assume that the oralloy in the primary pit wasof a higher grade than the oralloy in the secondaries.If this line of reasoning is correct, it would increase the likelihood that no pit piecesfrom the primaries had been recovered. This would be consistent with the generalpicture that all the ﬁssile material in the primaries had been dispersed in particulateform in the explosions. This would at the same time decrease the likelihood thatthere would be any pieces of the primary pits to take into consideration in the ﬁnalcalculation of dispersed plutonium. Not having access to the evaluation reportsof the ﬁrst 23 shipments of recovered weapons parts, this is, of course, only anassumption.Continuing along this rather speculative path, we would then surmise that allthe recovered pieces of uranium 235/oralloy came from the secondaries. From aUSAF document that cites an AEC analysis, we know that substantial quantitiesof uranium were in fact recovered, to be precise 85% of the uranium from threesecondaries.The full quotation goes like this: ‘An analysis by the AEC of the recovered secondarycomponents indicates recovery of 85% of the uranium and 94%, by weight, of threesecondaries. No parts of the fourth secondary have been identiﬁed’ (Broken ArrowThule 1968).Let us keep this in mind when we come to the analysis of the ‘missing component’.We should note, though, that we cannot know whether the 85% is a reference to allkinds of uranium present in the secondaries, including natural uranium (tuballoy),or only to uranium 235.62

30 March 1968 marked the oﬃcial termination of the evaluation and recovery portionof Crested Ice. This date gives a somewhat better understanding of the situationthan Lee Hancock’s remark in doc. 106883, where he reported that the search forbomb and aircraft debris on the surface of the ice was considered complete as of 20February. This is not correct, or should at least be understood as meaning that nowthe hunt had changed format and had become a search for parts buried in the ice.While Hancock was writing his sentence, the hunt for oralloy parts was continuingon the ice.18-19 March 1968, AEK 18-19/3 1968Notes [informal] from Danish-U.S. meetings in Washington. This was the meetingwhere the so-called ‘Gentlemen’s Agreement’, which had been reached in Copenhagena month earlier, was supplemented and ﬁnally codiﬁed.Let us make just a few points from the Danish notes. First, Walske said that allinformation about absolute amounts was conﬁdential. It is not said in the notes whetherthe ﬁgure of approximately 6 kg was mentioned. Secondly, Langham estimated that‘perhaps 5 percent of the plutonium had been impinged into aircraft debris.’ Assuming7.5 kg of plutonium in the four weapons, this would equal roughly 0.4 kg.Walske mentioned that ‘the U.S. would like to search for attractive parts.’ This could,of course, only be understood as weapons parts. H.H. Koch answered that the Danishauthorities would scan the area and discuss the results with the American side ifsomething was found. A little later, Koch asked whether there was going to be a seabottom survey. Walske proposed a formulation, which in the ﬁnal agreement runsas follows: ‘11. The question of a possible sea bottom search was reserved for furtherstudy of costs and utility by the U.S. Air Force. Should such a search be undertaken,the results would be made available to the Danish AEC.’Koch agreed to this solution, and Walske explained that the U.S. ‘would hardlyrecover anything. The Air Force would like to know something, but would rathernot drag out the operation. There was also a cost consideration.’ [‘Walske: Vi henternæppe noget op. Airforce vil gerne vide noget, men vil nødigt trække afslutningenud. Også cost consideration.’].The above remarks by Walske indicate that, already in the middle of March, it wasknown that an ‘attractive’ weapons component was missing. We see here some ofthe ﬁrst signs that a bottom survey might become desirable. Contrary to what the63

BBC journalist, Gordon Corera, believes, the Danes were told early on that the U.S.might decide that it would be desirable to search for ‘attractive parts’.From a purely chronological point of view, we are in the middle of a chain of eventswith uranium 235, also known as oralloy, playing an active part. This begins witha speciﬁc eﬀort to recover oralloy parts on 6 February. Further on, some of themain events are ﬁnds of some of the oralloy parts at the end of February and thebeginning of March, the possibility of an underwater survey in the Danish-U.S.agreement of 19 March, then the Sandia report of 2 May 1968 (doc. 107032),in which the missing object is deﬁned. Further events on the timeline are, forexample, a meeting in Copenhagen on 18 July 1968 between General Glasser andH.H. Koch with seven participants (see below) concerning a bottom survey, andﬁnally, the dives in Thule in August and the debrieﬁng of participating Air Forceoﬃcers in September 1968.19 April 1968, doc. 107038Memorandum from H.D. Bruner, Assistant Director for Medical and HealthResearch, Division of Biology and Medicine, AEC. The subject of the memo is theconference with the Danish representatives at the Pentagon,March 18-19,whichwe have just followed in the Danish notes. It is a useful seven-page document withappendices, and well written.One fascinating aspect of the document seen from a weapons-recovery pointof view is Dr Langham’s formidable reconstruction of the crash and whathappened to the bombs in the second that the nose of the aircraft hit the ice. Inan interview many years later, in 1995, Langham’s wife, Julie Langham Grilly,still remembered that he was very involved in discovering how the plane hadcome in (Grilly 1995).In any discussion about the perhaps special fate of one of the bombs based on theapparent utter destruction of one of the tritium reservoirs and one of the parapacks,the following part of Langham’s reconstruction is of special relevance. Here is whatBruner wrote about this part of Langham’s presentation: ‘The high explosive of theweapons detonated beneath the main fuel tanks and hence the amount of fuel in thecenter of the cracked area is minimal. The very high explosive force of the weaponswould account for the reticular arrangement of fracture lines and distorted iceblocks.He also postulated that one weapon exploded ﬁrst and its shock wave then set oﬀthe other three. It seems likely that the explosion disintegrated the Pu and alloy,64

and surrounded as they were by fuel tanks, etc., this metal ought to be impacted onand into the surfaces of one side of many, but not all, pieces of wreckage metal; thisis what was found.’1 April 1968, doc. 107047Report about examination of shipments of weapons debris nos. 24 and 25 from W.Lee Hancock, representative of the AEC at LASL, Albuquerque, New Mexico, toGeneral Giller in AEC Headquarters, Washington.This report and the subsequent doc. 107041 of 12 April are interesting in that theygive us an idea of what it would have been like to have access to the main report ofthis kind, that of 13 March covering the examination of the ﬁrst 23 shipments. Thereis a link between document 107007 (6 March), the present 107047 (1 April) andthe subsequent 107041 (12 April).The items in these shipments were presumably shipped from Thule after 6 March(doc. 107007).Two pit pieces and one secondary piece have been examined at Los Alamos. Thefact that the pieces had been sent to Los Alamos ﬁrst instead of directly to RockyFlats might be of signiﬁcance in itself, perhaps an indication that the pieces werebelieved to be oralloy.The ﬁrst piece, called ‘a piece of a pit’, was ‘three inches long and one half inch wide’.Another object is also identiﬁed as a piece of a pit. The pit parts were ‘sent to RockyFlats for further inspection and analysis’.‘One piece of segment from a secondary [several lines deleted]’ had also beenexamined. It, too, would be sent to Rocky Flats for ‘trial ﬁt of the secondary piecesto the pieces of segment or [word deleted] from secondary 28-1103 or secondary28-3573.’ The secondary numbers are speciﬁc for the secondaries and diﬀer fromthe bomb numbers.We can speculate that these two secondaries were less than intact, possibly in bits andpieces, as opposed to a third secondary, which had been recovered relatively intact.In doc. 106854 the two secondaries are described in these words: ‘other pieces ofsecondaries now at Rocky Flats’. It could well be that the ‘missing weapon component’belonged to one of these two secondaries.65

section in doc. 106887 of 24 February. In that case we concluded that the recoveredﬁssile core belonged to bomb no. 1, SN 690020.The reasoning is simple enough. In relation to these two weapons, SN 453171and SN 815950, it may have been possible to see or at least have an idea of whatwas missing, and then to give Sandia a complete, very exact description of themissing weapons component, as was done four days later, when the AEC/ALOasked Sandia Corporation to assist in deﬁning an underwater search area oﬀ thecoast of Thule.But since we believe that some pieces of uranium 235/oralloy from the secondary pitshad been identiﬁed with bomb SN 815950, this makes SN 453171 the most likelycandidate for a missing uranium part among these three weapons.One candidate for the ‘missing weapon component’ could thus be hidden in theexcised part of the present document 107047. On the basis of that one piece ofsegment from a secondary that is mentioned at the start of the deleted paragraphand the state it was in, the experts were perhaps able to deduce something about acomponent that had been inside the segment but was now missing. We are workingblindfold here and cannot, of course, be sure that this is the case. But perhaps thisis one place where something is mentioned that refers to our idea of the missingcomponent, namely a piece of oralloy/uranium 235 from the ﬁssile material in thesecondary stage of the weapon.We may or may not be dealing with a situation in which all of the oralloy in thesecondary is missing. It might be that only a small broken-oﬀ piece of oralloy wasmissing from the jigsaw. See, for example, the words in the last lines of the clip above.Very soon we will see that the Americans were in fact guessing that an intact oralloycomponent might be missing, but how could they be sure? They could not, of course.After all, some of the recovered oralloy pieces were rather small.How big would the oralloy (uranium 235) element in the secondary stage be? Maybeabout 8 kg, which in volume would be less than 0.5 litres. Uranium and plutoniumare both heavy metals, roughly twenty times heavier than water At this stage inour investigation, we cannot be sure of the shape of this component, nor whetherit was divided into several sections or whether one of these sections was perhaps ofsuch a sophisticated nature that this feature in itself would make it especially worthlooking for.67

On the basis of the excised parts of the Sandia document below, doc. 107032, we willspeculate a little further on the physical characteristics of the object and whether itwas suspected to be whole or in pieces.Anyway, what is interesting is that what the Americans may have been looking forwas something with a volume of less than half a litre. Supposing that this item wasat all whole, which they could not be sure of, it could still be said that this would bea very small item to spot on the sea bottom in the middle of thousands of pieces ofmainly aircraft debris.5 April 1968, doc. 106854Ninth status report from General Giller to the AEC chairman.This is Giller’s summary of Hancock’s report of 1 April, which we have justanalysed. In his opinion, two of the pieces in Hancock’s report are of interest.In spite of the excision in this document, we have the candidates for them in theformer document.

The two short deletions above oﬀer a welcome opportunity to discuss a questionof terminology. The problem is simple. These important documents abound withpit pieces and pit parts that clearly refer to the ﬁssile core of the secondaries, butwe have not yet found an expert or a piece of literature to conﬁrm that the term‘pit’, which is normally reserved for the ﬁssile core of the primary stage, couldalso be used for the ﬁssile material in the secondaries. The way to distinguishbetween the two could then, for instance, be to speak of the primary pit versusthe oralloy pit.This usage is probably what we ﬁnd behind the black bars above. Let us try toput the two passages beside each other and ﬁll the black area in as we believe itshould be done:1) ‘We have identiﬁedoralloypit pieces…’2) ‘No pieces have yet been identiﬁed to be fromprimarypits.’It follows that the identiﬁed oralloy pit pieces do not belong to the primary pits.If we are correct, it was normal usage at this time to speak of a pit not only in theprimary but also in the secondaries.

5 April 1968, Walske-Koch 5/4 1968Letter from Carl Walske to H.H. Koch.Among other things, Walske answered a question from Koch about the possibilityof a sea bottom search. He informed Koch that this matter was being considered byhimself and General Glasser, but more in the way of some photography below the impactpoint rather than a search. The decision would be greatly inﬂuenced by whether ornot something simple in terms of manpower and expenditure could be devised. SinceAugust would seem to be the most favourable time for such a search, there was stillsome time before a decision would be necessary. The Navy people were looking into thematter, and Walske expected to be able to give Koch an answer within a few weeks.Two brief comments may suﬃce. The ﬁrst is a rather obvious observation that we arenot witnessing the preparations for a high-priority underwater operation. The secondis to point out that, with examples of this kind, we have slowly started a brief processof disproving the mistaken assertion of Gordon Corera, the BBC journalist, that theDanish authorities were deceived in the matter of underwater operations.15 April 1968, Walske-Koch 15/4 1968Another letter from Walske to. Koch, who had invited Walske to visit him inCopenhagen, where they spent May 28 and May 29 together. As it turned out, theoccasion was used for a meeting at the Danish Atomic Energy Commission. Againwe think that Corera got it all wrong if he believes that Dr Walske was going tospend two spring days in Copenhagen deceiving Mr Koch.Enclosed are the radiological survey data from the Air Force accident report, ﬁveappendices from Annex B and three appendices from Annex I (cf. Crested Ice SAC.1969). These same appendices were sent to the Danish government once again in 1988. Yetanother letter from Walske to Koch about various matters was sent on May 2, this timewith a brief remark that the underwater operation had not been decided on as yet.22 April 1968, doc. 107036By the end of April, Sandia Corporation had completed its study of the accident inorder to develop the parameters of an underwater search for missing weapon debris.Where was it likely to be found?The Department of Defense (DoD) was interested in the consensus of the AtomicEnergy Commission (AEC) regarding the desirability of conducting an underwater71

search. The Air Force had considered various approaches in conducting such a search.The object of the search is probably identiﬁed in the deleted passage below, beforethe words ‘under-ice concept’.The under-ice concept discussed in the document would have had the U.S. Navy asthe entrepreneur, but it was discarded as not being within the current capability ofthe Navy and not doable in the time remaining to conduct search operations fromthe ice surface prior to ice breakup. This appears to indicate that the Navy’s Curvsystem could have been involved, which had also been employed in Palomares. It allﬁts with the manner in which the Curv system would have been deployed.Instead, the Air Force funded the Navy to evaluate various concepts of searchoperations which could be conducted after the ice had melted and when the baywas clear for surface operations. In the meantime, a group of oceanographershad been working at the Thule site in an eﬀort to estimate where residue mightdrift as a result of currents. This group was scheduled to brief Walske on 24April 1968.

The Air Force did not expect a very complicated search since the ‘water is relativelyshallow (approximately 600 feet at most) and the bottom of the bay has thecharacteristics of a small desert. Considering the fact that the point of entry into thewater is pinpointed and the terrain to be searched is smooth, use of a towed sonarsled and closed circuit TV appears to be a logical search approach.’It appears that at this point in the discussion, the Coast Guard stated its willingnessto support the logistics eﬀort and that ﬁnally a manned submersible such as theNavy’s Perry Link deep diver might also be needed.As noted previously, Sandia Corporation had already completed a study that couldbe useful in deﬁning the area for search operations.The DoD had been giving some thoughts to the desirability of an underwater search.On the one hand, a search would lead to questions about what might be missing and,clearly, even a very extensive search might be unsuccessful. On the other hand, even abrief search might ﬁnd sensitive classiﬁed debris which another nation might recoverif the Americans did not. DoD found that a reasonable approach might be to let theextent of the underwater search depend on the results of a brief underwater survey.Now, 41 years later, the sentence that ‘a search would lead to questions about whatmight be missing’ has proved itself to be a visionary one.These considerations reﬂect very clearly that the missing object was not a bomb.Had this been the case, the argument would have been completely diﬀerent, andthere would have been no discussion of pros and cons. The search would have beenperformed in a massive way, period. It is obvious that the search in Thule was noteven remotely considered as important as the underwater operation in Palomarestwo years earlier.The approach proposed by the DoD also shows that it was not at all convinced thatthe missing object was there or that it could be found. Its attitude could best bedescribed as rather relaxed: ‘If the object cannot be found with a relatively limitedeﬀort, so be it!’The arguments we have heard above should, we believe, be taken seriously only toa certain extent. They are reminiscent of a not so unusual pattern of behaviour inbureaucratic systems, in which many agencies and individual agents have a tendencyto cover their backs against the eventuality that some superior or competitor should73

ask the dreaded question: ‘Do you mean to say you’ve done nothing?’ Should thishappen, it is preferable to be able to say: ‘Sir, we gave it some very serious thoughtand we even tried, but unfortunately…’.26 April 1968, doc. 909970At a short information brieﬁng before lunch, the AEC had 33 diﬀerent items onthe agenda, ranging from UK views on a gas centrifuge to an oﬃcial entertainmentauthorization (within which the staff would consider the possibility of anAEC−Department of State reception) to travel expenses for a Lawrence award medalist.Thule was item 18 on the agenda. The commission approved a brief underwater surveyfor weapon debris. This document was declassiﬁed as early as 1986.2 May 1968, doc. 107032This document is the study by Sandia Corporation that aimed to develop an estimated‘footprint’ of underwater trajectories which could be of assistance in the search fora speciﬁc piece of weapon debris at Thule, a ‘missing weapon part’. There is no wordof any bomb.

We promised to return to the question of the characteristics of the missing object,and here we now go, despite being blindfolded by the deleted numbers in the aboveparagraphs.First observation: it is neither a bullet nor a cube. These objects do not have length andends. Second observation: we can deduce that it is a cylinder with rounded ends. Ithas length and a spherical radius in both ends, and the cross-sectional area is circular,since the cross section has a diameter which is the same at both ends of the object.As to the hydrodynamic section, the lower the drag coeﬃcient (strømningsmodstands-koeﬃcient),the better the hydrodynamic characteristics of the object. Referenceworks say that a penguin has a drag coeﬃcient of 0.03, a smooth sphere has a dragcoeﬃcient of 0.1, a rough sphere a drag coeﬃcient of 0.4, a cone 0.5, a long cylinder0.82, a cube 1.05, and a short cylinder 1.15.Thus, Sandia’s drag coeﬃcient for the object (end on) of 0.6 would seem a near ﬁtfor a long cylinder with rounded ends.As we have shown elsewhere, a good deal of eﬀort was spent in recovering piecesof oralloy/uranium-235 from the secondaries. The reader may also recall that DrChambers, in his interview with the BBC, was speaking about ‘the radioactivematerial’. The reference value for nuclear weapons of this generation is about 2 kgof plutonium and 16 kg of uranium 235. In order to reach the suﬃcient amountof ﬁssile material in the primary pit, we surmise that roughly 8 kg of uranium wereneeded as part of the primary pit (Albright et al. 1993. The presence of U-235 inthe primaries of the concrete weapons has been known since the ﬁrst release ofDOE documents in 1994 and has been conﬁrmed by Eriksson 2002, 2008, andby Nielsen & Roos 2006). This guess leaves 8 kg of uranium 235 for the ﬁssilecore of the secondary stage. Another indication is the 20-pound section, whichwas mentioned under 24 February (doc. 106887).Against this background, we can allow ourselves a few conjectures. If the cylinderwere a compact uranium rod, representing the so-called spark plug or ﬁssile core ofthe thermonuclear secondary stage of the weapon, and if the amount of uraniumwere 8 kg and its density 19.1 g/cubic centimetre, then the volume of the cylinderwould be approximately 419 cubic centimetres, less than half a litre. We shouldemphasize that we do not know the actual amount of uranium 235. What we haveare merely indications.75

If this volume were distributed in a solid cylinder with a diameter of 3.3 centimetres, thenthe cross-sectional area would be 8.55 square centimetres and the length of the cylinderwould be about 50 centimetres. We may add that uranium is a little softer than steel: itis malleable, ductile and slightly paramagnetic. What is more important, crumbling ofuranium metal during corrosion in water has been observed in many studies.Lest the reader believe that we think the decimals are important, we had better saythat it is of no importance for the argument whether the diameter is 3 or 7 or anyother ﬁgure. We should also leave open other possibilities. For instance, the sphericalends of the cylinder may have formed part of an external casing of the uranium. Ifthis casing were part of the wanted cylinder, the dimensions would be somewhatlarger.Why would a uranium rod have spherical ends? Could it have something to dowith the rod being hollow, in other words a pipe, and that the rounded ends were aconvenient or solid way to close the pipe? Or was there some other reason for thissealing of the rod? Was it to make sure that the radiation pressure on the pipe wouldonly be exerted from the outside? A metallurgist, chemist or physicist might answerthis question. It is often mentioned in the literature that the spark plug could behollow, and this is in fact the most likely scenario.In doc. 107047, which discusses recovered pit pieces, almost certainly from secondaries,the wall thickness of the pieces is discussed several times. This would seem toindicate that the uranium pit was indeed hollow. We would not be surprised if theuranium/oralloy pipe were designated by the term ‘secondary pit’ in excised partsof the documents, although we cannot substantiate this assumption with evidencefrom the literature or interviews.Since we do not know the construction details, we must obviously also allow forthe possibility that the uranium cylinder was kept in some form of casing. Still, theuranium cylinder would be the prize.For those who are mainly interested in the external dimensions of the spark plug andthus the chances of spotting it, the pipe would obviously be a little thicker and morevisible than the solid rod. If we use the same values as above but assume an externaldiameter of 5.4 centimetres and an internal diameter of 4.3 centimetres, the lengthof the pipe would again be roughly 50 centimetres, whereas the wall thickness wouldbe 1.1 centimetres. Again, this is based on conjecture and a few indications only.76

It would not have been an easy task to ﬁnd such a small object on the sea bottom underany circumstances. Furthermore, we should remember that, although the Americanswere looking for the whole object – the description of an object with two sphericalends tells us that – they would also have to allow for the possibility of ﬁnding only apart of such an object, or that it could have been broken up into even smaller pieces.These could have been overlooked in the ice and snow on the surface, or been scatteredamong thousands of pieces of small aircraft debris on the sea bottom, or in fact alreadybeen partially collected on the surface. A small object, yes, but bigger than a spark plugin a car. We have chosen to call it the marshal’s baton instead. The size ﬁts better.If such a small object really did fall to the sea bottom, there is little chance of itbeing visible and distinguishable in the side scans performed in Bylot Sound in2003 by the Geological Survey of Denmark and Greenland (GEUS 2003). In fact,it would have crumbled long ago.The sedimentation rate on the bottom is 2-4 mm per year, that is, 8-16 cm duringthe forty years since the accident. The new sediment has been eﬃciently mixed intothe old layer through biological activity (Dahlgaard et al. 2001).According to the sketches below, Sandia Corporation believed that the object mightbe found on the sea bottom somewhere between 50 and 150 feet from the impactpoint. These possible locations were based on various assumptions about the object’soriginal velocity, impact angle and attitude in the water: side on or end on?As it will be recalled, doc. 107036 mentioned the eventuality that a foreign nationmight recover the object if the Americans did not do it themselves. It is hard tobelieve that this was really a very serious concern, and the relaxed atmosphere of thedocuments speaks against it.First of all, the object was of relatively minor importance in the perspective of thedecision-makers. Secondly, the risk that the Soviets should be snooping around forit and actually ﬁnd it was in every sense of the word very remote and thus a riskworth taking if need be.Having determined the likely identity of the missing object, we can now move on tosome of the documents concerning the search operation. But ﬁrst we must introducean additional piece of information about the state of the ﬁssile material from theprimary pits.77

Based on the ﬁndings in recent years of hot particles in the sediments in Bylot Soundwith homogeneously integrated uranium 235 and plutonium, the question arises asto whether this integration of the materials had already taken place as bonding inthe production process. To a layman, the account above indicates that the primarypit was a normal composite pit.The composite pit had several advantages over using the materials separately. Asingle design could be used, employing both the available weapon materials. Usinguranium 235 with plutonium reduced the amount of plutonium and thus the neutronbackground, and it also required a smaller critical mass than if uranium 235 wereused alone.The scientists doing the monitoring in the area can tell us if this indication is ofrelevance for their work.It is now more than twenty years since this document was declassiﬁed with deletions.It might be time for a new security review of the large excised part of the document,along with the ﬁnal report on the amounts of ﬁssile material on all recovered partsof the aircraft.79

28 May 1968, AEK 28/5 1968At a meeting in the Danish Atomic Energy Commission with H.H. Koch and CarlWalske as the top negotiators and ten further participants, the main topic was the‘ecological summer programme’, that is, monitoring and ﬁnal clean up.Concerning the ‘underwater research business’, Walske said that this would probablybe decided in the following week, that it was to some degree an ﬁnancial problem(a cost of 200,000 dollars), and that it might not be necessary. One of the Danishparticipants, trying to be helpful, suggested that it might be possible to include somesea bottom photography in the Danish summer programme.Walske answered that he would consider that seriously, while Koch commentedthat there was no reason to exaggerate the sea bottom thing. ‘Jo mere man gør, jomere vil folk tro vi er i tvivl’ [‘The more you do, the more people will think we are indoubt’]. He considered it best to follow the proposal to include some photographyin the summer programme, and that would be it. Walske said that he would discussthe matter back home.

The chairman’s direction to retrieve bomb debris would not be easy to follow if bigpieces had been located. The submersible was not capable of any large-scale recoveryoperations. It was equipped with a mechanical arm ﬁtted with a claw and couldrecover small pieces of perhaps up to 20 kilograms.2 July 1968, doc. 107107Message from James L. Olsen, Livermore, California, to among others Ray Stone atDMA, AEC in Washington, Wright Langham at Los Alamos, Colonel Montoyaat SAC HQ at Oﬀutt AFB, Nebraska. James Olsen asks Ray Stone to retransmitthe message to one of the team chiefs, a lieutenant colonel working with ProjectCrested Ice in Thule.The message recommended various methods of data collection for metallic objectsthat could turn out to be uranium pieces. Again we hear about the SPA-3 probes thatcould be submerged to the objects from a helicopter in order to identify them. Theprobes could be set to an upper level ratio of 3.3 and a peak response of 185 keV, which,we now recall, is the footprint of uranium 235. Twice the report mentioned uranium238. We do not know what to do with this information. It is hardly a misspelling for235, but might be an attempt to conceal the real purpose for somebody.The document recommends two other methods of data collection as well, namelyto carry out a thorough and continuing photographic programme on the broken icearea until it disappeared, and to obtain infrared photographs from the same area.All of these recommendations reﬂect an ongoing eﬀort to collect radioactive piecesof the weapons. The hunt for the marshal’s baton was still on, this time from both81

boat and helicopter. The heat signatures of radioactive objects depend on their half-life. Thus the heat signature of plutonium would be stronger than that of uraniumby a factor 30,000. The chances of ﬁnding the marshal’s baton or its fragments inthe brash ice by infrared imagery were probably small.18 July 1968, notits 18/7 1968This document is a short Danish summary of a meeting that took place at the DanishAtomic Energy Commission. The participants were the chairman of the commission,Under Secretary of State H.H. Koch, Major General Glasser, U.S. Air Force, Gjørupfrom Risø, two oﬃcials from the U.S. Embassy in Copenhagen, and two secretariesfrom the Commission and the Danish Ministry of Foreign Aﬀairs.At the meeting, General Glasser announced that it had been decided to undertake aphotographic survey of the sea bottom in a circular area with a radius of 100 metresfrom the impact point. This would be done with a small submersible that wouldmake daily diving expeditions over a week in August. The submersible would notbe capable of any recovery operations. Close, but no cigar. As we have just learned,Star III did indeed have a very limited capability for recovery operations, but onlyfor small objects of perhaps up to 20 kg, as was the case for Star II.This fact was, on the other hand, no big secret. It was common knowledge on thebase, and furthermore, the joint Crested Ice report has a ﬁne picture showing StarIII in Thule, with the claw used for small recovery operations clearly visible underthe nose section. The reader will ﬁnd a collection of photographs on the website ofthe report, showing the claw in action at the bottom of the sea. Walske sent thesepictures to Koch, and they are now at the Danish National Archives.The Danish Atomic Energy Commission and General Glasser were in agreement thatthe surveys and clean-up operation that had already been performed made it highlyunlikely that the pictures would give any indications that there was any airplanewreckage or fragments of nuclear weapons on the sea bottom.It would be rash to guess about the possible details and doubts behind this professedagreement. Let us conﬁne ourselves to the obvious fact that, in the summer of 1968,Danish and U.S. oﬃcials discussed the possibility of aircraft and weapons residuebeing on the sea bed. This was part of a continuing discussion between them that hadstarted several months earlier in Washington, and the eventuality of such a searchhad been put in writing in the ‘Gentlemen’s Agreement’.82

The question as to whether the Danes might have been told informally that thesubmersible would be looking for a small uranium rod is in our opinion not ofoverriding importance. It would be quite another matter had the Americans suspectedthat there were plutonium components on the sea bed, not to speak of a whole bomb.If such an unoﬃcial announcement had indeed been made, and we emphasize thatwe are not aware that it was, it would most likely have had a reassuring eﬀect andbeen perceived as conﬁrmation that no bombs had been left behind.18 July 1968, AEK 18/7 1968According to the AEK’s hand-written minutes of the meeting, H.H. Koch commentedthat the search was a very useful step to make in order to make sure that nothingof importance was left on the sea bottom, and that the Danish side was grateful forthis extra eﬀort (AEK 18/7 1968).

Koch also said that he was satisﬁed with this ﬁnal eﬀort. It had been discussed inWashington, and the Danish side was not going to press the issue of a bottom survey.If, however, the Americans were to do it, the Danish side would be happy with that,since it would mean that no stone was being left unturned. [‘…, vi ville ikke pressepå med noget vedr. bunden men hvis I vil gøre det er vi glade for det’.]H.H. Koch had more than suﬃcient information to understand that the bottomsurvey was not a major operation. He was in fact reassured by the dual signal of theAmerican decision. The small dimensions of the survey allowed him to conclude that83

there was no big bad wolf under the surface, and the fact that the survey was beingperformed after all was an extra guarantee that as much potentially harmful debrisas possible had in fact been removed.Context, Mr Corera! Use of sources from both parties when analyzing bilateralrelations, Mr Corera! And, Mr Corera, inconvenient though it may seem, even useof sources in strange languages from countries not enjoying the unspeakable fortuneof being partners in the Anglo-Saxon media orbit.The main constituent in the Danish handling of the case was a concern for theelimination of as many of the consequences of the accident as possible. This chiefconcern was accompanied by carefully balanced eﬀorts of crisis-management with thegoal of establishing the necessary safety regulations on the one hand and avoiding panicon the other. Finally, the Danes respected the secrecy concerns of the American sideas long as they were not felt to interfere seriously with their own main concerns.The cross-pressures and apparent paradoxes arising from considerations of secrecy,foreign relations, crisis management, and public diplomacy are not unusual in thehandling of such cases. They may to some extent be bridged with instruments fromthe tool-box of diplomacy such as the cultivation of conﬁdence and cordial relationsbetween main negotiators. This was well understood by H.H. Koch and Carl Walske.These features are trivial and can easily be described in a newspaper article. However,they are admittedly not ﬁt for journalistic stand-up bravado in distant locations.Mr Corera’s fairy tale should not deﬂect attention away from what is relevant today,namely the continued monitoring of the eﬀects of the accident. With equal measuresof professionalism and common sense, H.H. Koch and Carl Walske succeeded inﬁnding mutually acceptable solutions in a diﬃcult situation in which Danish-U.S.relations had to be handled under the conﬂicting pressures of creating a durablediplomatic solution to the question of the U.S. nuclear presence (absence) from theskies of Greenland, and the clean-up operation after the Thule accident. Thinkingalong stochastic lines, it was not to be expected that the same degree of professionalismin handling matters pertaining to the accident would endure over the next fourdecades without occasional aberrations.27 July 1968, doc. 107095Telex from the Chief of Staﬀ of the Air Force (CSAF) that the underwater operation hadbeen authorized and was ready to begin. This was declassiﬁed many years ago, in 1991.84

The main part of the telex was about the operational requirements. The conﬁdentialnature of the fact that the operation included a search for an object or weaponpart can hardly come as a surprise to anybody. There were many good reasonsfor this. The same was said in doc. 107113. Referring to the extended diplomaticprehistory of the underwater operations, we may tell the BBC journalist on thequiet that his sensational assertion about the Danes not being informed as tothe real purpose of the dives is about as far from the reality as Oxford is fromThule.It is diﬃcult to see why an astute observer such as Mr Corera, who has writtenextensively on the British and American intelligence community, would base suchmisleading assertions on one or two U.S. Air Force documents and fail to take intoaccount the hierarchical and compartmentalized nature of conﬁdentiality and secrecyin foreign relations.As we have noted already, it is slightly disconcerting that a journalist who takessuch apparent interest in archival research that he has requested 348 documentsfrom the DOE archive in Nevada and has been sleeping with them under hispillow for seven years has been unable to locate the Danish National Archive onthe map. It is somewhat puzzling that he ﬁnds it possible to pass judgment on thebilateral relations of Denmark and the U.S. concerning the underwater operationexclusively on the basis of a few American documents, generated outside the mainnegotiating circuit.24 August 1968, doc. 107074We now return to Thule, where the diving operations had started in August. Elevendives were performed, with an average of three hours productive survey time per dive(Crested Ice 1970, 95). Document 107059 diﬀers by stating that actual search timeper dive was only 1.5 hours. At the Danish government’s request, the Americanshanded over videotapes containing sixteen hours of footage from the dives in Apriland May 1988 (HIAS 1988).This document is the daily situation report, with an account of dive number 7 of StarIII. The situation reports, eleven altogether, were of low classiﬁcation: ‘For oﬃcialuse only’. As is evident from doc. 107072, which is analyzed below, there were alsoreports classiﬁed ‘Secret’. We cannot expect to ﬁnd any important informationabout sighted weapon parts in the daily situation reports that were classiﬁed ‘foroﬃcial use only’.85

A circular area around the datum point was surveyed for a distance of 180 feet.Debris extended ‘in a northerly direction from slightly south of the datum point tothe 180 foot circle.’ The concentration was ‘quite heavy to the 120 foot circle’ andappeared ‘to decrease from the 120 foot to the 180 foot circle.’‘During this dive, two diﬀerent red fabric bags were sighted’ and an attemptmade to recover them. This was the kind of recovery capability the submersiblehad. It is speciﬁcally mentioned in the document that the manipulator of StarIII had been repaired and would be used in the attempt to recover the bags.The manipulator was a mechanical arm that could be ﬁtted with various tools,in this case a claw. Those who have seen the videotapes from the dives canconﬁrm that the claw did in fact work (HIAS 1988; cf. photos on www.diis.dk/thuleaccident).

None of this heavy and medium debris was visible on the extensive side scan sonarsurveys performed by the Geological Survey of Denmark and Greenland (GEUS)in 2003 (GEUS 2003).27 August 1968, doc. 107072This is a supplementary situation report, originally classiﬁed ‘Secret’ and for limiteddistribution only (limdis). As mentioned above, the daily sitreps were classiﬁed as‘Oﬃcial use only’ and did not contain any information about weapon parts of anyimportance sighted on the sea bottom.We learn that two observers, air force oﬃcers from the Directorate of NuclearSafety, taking part in the dives, had identiﬁed ‘pieces of external and ballistic

case section [deleted] during dives number 8 and number 9 of 24 and 25 August1968.’ They had also seen an ‘external ﬂat cable raceway with connectors missing’,that is, without connectors. An extensive excision covers the remainder of theparagraph.We are further told that the weapons parts mentioned here were the only onesobserved during the dives.There is nothing remarkable about the bracketed word ‘(noforn)’ in the last line. Aswe have heard before, the Americans had a closed circuit for detailed informationabout ‘secret restricted data’ associated with found weapon components. It was fullyconsistent with this principle that Dr Vibe and his associates should not see picturesof the weapon debris.Incidentally, a rich collection of unclassiﬁed pictures from the diving operations arepreserved in the archival holdings of the Danish Atomic Energy Commission in theNational Archives in Copenhagen (Rigsarkivet), and as already noted, sixteen hoursof video footage from the dives have been handed over to the Danish authorities(HIAS 1988).Methodologically, this case serves as a reminder that, in a situation in which‘secret restricted data’ are involved, one will most likely not obtain the full pictureby reading only documents of low classiﬁcation. Not surprisingly, there are two89

completely diﬀerent stories of the dives in these few documents. Furthermore,there is always the possibility that there are documents to which one has no accessat all. It is hard to know when and if one is seeing the whole picture. In thiscase, there may be a double or triple fence, ﬁrst the excised part above, and thenpossibly a special report on the ﬁnd in the excised part. It appears that we willhave to wait a little while, before these classiﬁed parts and pieces of documentscome down to us.We will now pretend that this is the only information we have about this ﬁnd. We dothis merely to demonstrate the futile speculations to which excisions will sometimeslead the historian. Fortunately, after this small experiment with, as it turns out, itssometimes ﬂawed speculations, at least a partial solution is at hand in the followingdoc. 107059, or rather in the attached sketch.The external case section may be the outer case of the weapon, whereas the ballisticcase section may be the part around the sealed portion, including the primary/ﬁssiontrigger and the secondary/thermonuclear stage. If this is so, it begs the questionwhether this piece of the ballistic case section was in such a condition that some ofits original contents remained.The remark about an external ﬂat cable raceway without connectors conveys theimpression that the components to which the cable raceway had been attached werein pretty good shape. Moreover, the sheer size of the excised paragraph might lead usto believe that there was a good deal to say about this ﬁnding, whether it had turnedout as expected or not.This leads us to the next question. Given the amount of attention devoted to identifyingand associating bits and pieces of the weapons found on the ice with speciﬁc weapons,were these pieces really not recovered in an endeavour to associate them with a speciﬁcweapon? Were they or the components of the secondaries that were found on the iceclose to the impact point in such a condition that the possibility that they belongedto the same weapon as the pieces on the sea bottom could be ruled out? Or the otherway round, when combined with what was known about the weapons componentsfound on the ice, what were the indications that the ﬁnds on the sea bottom werepart of, for instance, a third or fourth weapon?Could these questions be answered simply by looking at the pieces under water andtaking pictures? Or was the ﬁnd in itself and the information contained in the excised90

paragraph of such a character that it constituted one important last piece in the jigsaw− a piece in the jigsaw that alleviated some very residual worries possibly existingright up to this moment that ‘secret restricted data’ or objects of some operationalsigniﬁcance might be hidden on the sea bottom?We do not know the answer, but we can take note of the perhaps surprising easewith which the decision was taken to discontinue the operations of Star III. The factremains that the diving season could have been extended for nearly a month more. Ifthere had been a vital interest in prolonging the operations, bureaucratic diﬃcultiesor inﬂexible planning would hardly have prevented it.Here ends the experiment in which we have pretended not to know the sequel.It is quite obvious that the underwater operation at Thule was conducted with amuch lower priority than the one in Palomares. When we compare the limited sizeand the decision to discontinue the diving operation in Thule with the extraordinaryand successful eﬀorts to recover the missing bomb in Palomares, we understand thatthey were extremely diﬀerent in size and importance. This in itself should tell us thatnobody was looking for a bomb.The mere fact that Star III, with its very limited recovery capability, was chosen forthe operation is another telling indication that the Americans were not looking forsomething as heavy as a bomb, neither the physics package (the primary and secondarystages), nor the secondary stage of a bomb.10 September, 1968, doc. 107059Tenth status report from General Giller to the Chairman of the AEC and theCommissioners. This is the last and most important of the documents concerningthe search for weapon components on the sea bottom. It was originally classiﬁed‘Secret’ and deals with the same events as the 27 August 1968 doc. 107072, but ithas a good deal of supplementary information. Many of the questions raised by doc.107072 of 27 August 1968 are answered by this document, but not all.That said, this status report hardly tells us everything from the debrieﬁng of thethree Air Force oﬃcers in Dr Walske’s oﬃce in Washington. The minutes of thatdebrieﬁng have not come down to us, nor have the ﬁnal reports on the results ofthe dives by the Directorate of Nuclear Safety and the CSAF.

But ﬁrst a few words about the decision process that is described in the ﬁrst sectionof the document. After the observation of small weapons parts on August 24 and25, the Chief of Staﬀ of the Air Force had granted approval to extend the searchthrough to August 28. However, the last dive scheduled for August 28 had to becancelled due to bad weather.We might see this as a sign that the commitment to ﬁnd the object was not that high.The reason for this, we think, is that it was not considered of vital importance to ﬁndthe missing marshal’s baton. The decision of the Chief of Staﬀ to extend the operationby one single dive sounds more like ‘For Heaven’s sake, then, take one last look!’Similarly, Commissioner Tape from AEC, Dr Walske from DoD, and GeneralGlasser from Headquarters U.S. Air Force agreed that the ‘survey operations couldbe terminated. With the concurrence of the Secretary of the Air Force the on-scenecommander at Thule was told to cease operations, demobilize and return all equipmentand personnel involved in the survey to the United States.’The whole atmosphere in which this matter was handled conﬁrms our analysis that,although of some importance, the underwater operation in Thule was clearly nota high priority in the same league as the underwater operations in Spain. It was, infact, a rather low key undertaking.The well-tempered words of Dr Chambers to the BBC, that ‘there was disappointmentin what you might call a failure to return all of the components’ conveys, we believe,92

Concerning the weapon parts, we are told that they were small and that they did notbelong to any secondary. In the attached sketch, we read a more exact description.The external case section is described as a section of the steel polar cap (14 x 14 x 12inches), while the other item was a section of the MC-706 warhead ballistic case (3x 1½ ft). Apart from that, there were the external ﬂat cable raceway that we heardabout earlier, and ﬁnally a section of steel locking band (a six-inch piece).The two case pieces were apparently empty or maybe ﬂattened by the explosion ofthe HE. However, the polar cap was described in three dimensions.

On the attached sketch, we have two concentrations of debris ‘A’ and ‘B’, each with3,000 to 4,000 small pieces of debris. We are reminded of Professor Kofoed-Hansen’sdescription that the B-52 had been blown into millions of pieces.We cannot avoid speculating that, if our suspected uranium marshal’s baton wereamong these many pieces of debris, it might have been rather diﬃcult to ﬁnd it withinthe very limited time frame. We can also make the more humble observation thatthe ‘missing [word deleted] in view of its ballistic characteristics’ is mentioned inthe singular. This is as we expected.Towards the end, the memorandum contains an interesting observation from thedebrieﬁng of the three Air Force oﬃcers. It turns out that considerable discussionwas generated during the brieﬁng by the unexpected location of the heavy debris inrelation to the impact point. This obviously led to further speculation that, in viewof its ballistic characteristics, the missing object might have come to rest beyond theobserved concentration of the heavy debris.Some of the participants in the brieﬁng may have visualized the slender, heavyuranium cylinder with its spherical end shooting like an arrow through the waterat high speed.94

not found out what is hidden in the perhaps 6-8 lines of excision in doc. 107072 of27 August.It was a somewhat diluted version of the American dives that was presented by thebase commander, Colonel C.S. Dresser, in the joint Danish-American report ‘ProjectCrested Ice’, published in 1970. ‘During August, Danish and American scientists, usinga 54-foot Danish motor launch MS AGLANTHA, and a 24-foot minisubmarine,STAR III, conducted repeated radiological surveys and ecological studies along theshores of Wholstenholme [sic!] Fjord to insure that no contamination remainedin the area.’ ‘That’s All Folks!’ as they say at the end of cartoons, and as painted inlarge letters on the end of the last tank being shipped from Thule, as shown on aphoto with Colonel Dresser posing in front. On the other hand, the article is to becommended for a ﬁne picture showing Star III with the claw clearly visible underthe nose section (Crested Ice 1970, 30f).The reason we suspect that General Giller’s status report does not tell us everythingabout the brieﬁng in Dr Walske’s oﬃce is that there is no mention of the ﬁnd thatis excised in doc. 107072. The video tapes that show the recovery of the engine dustcover also reveal the conspicuous interest of the Star III observers in elongated objectsapproximately 50 centimetres long. First they zoom in on a piece of ﬂat iron with screwholes, roughly half a metre long, but then pan away. Later, the claw of the submersibleremoves an object which is hardly more than half a metre long. Apart from the enginedust cover, there are no other recovery attempts on the videos (HIAS 1988).This remarkable behaviour appears to be consistent with Sandia’s description of themissing weapon component and thus represents a further piece of evidence that wewere probably on track in our analysis of the object on the basis of document 107032,and that this was the kind of object the Americans were looking for. However, on thebasis of the available evidence it seems likely that, on closer inspection, the recoveredpiece turned out not to be the sought-after cylinder of uranium 235.We said a little while ago that we did not know what is hidden in the perhaps 6-8lines of the excision of doc. 107072 of 27 August. Could it be a discussion of thewanted object, the cylinder, that had been recovered, only to be discarded again asnot being the real thing?If this object had indeed been the prize, there would hardly have been a remark indocument 107059 to the eﬀect that no parts of a weapon secondary were observed.96

Likewise, there would have been no reason to speculate during the brieﬁng that ‘themissing [word deleted] in view of its ballistic characteristics, might have come to restbeyond the observed concentration of the heavy debris.’This concludes our survey of the documents generated in the course of the clean-upoperation in Greenland.Before we leave this part of the report, however, we should consider adocument from 1969 which contains an estimate of the amounts of plutoniumcontained in the tanks and containers that were shipped to the SavannahRiver facility.9 June 1969, doc. 107117The document is a cover letter to a memorandum by General Giller dated 5 June1969. The clipping below is from Giller’s memorandum.The memo is about the contents of the containers with snow and ice from Thulethat were being processed at Savannah River. On 2 and 3 September 1968, 3151,800 gallon tanks had been sent from Thule to Charleston, S.C. (doc. 107059). By5 June 1969, 225 of these 315 jet engine containers with contaminated water hadbeen processed. The ﬁltrate called solid debris had been measured for its content ofplutonium 239. The plutonium content in the solid debris was estimated to be from2.2.kg to 3.9 kg.

The most plausible reading would be to understand the last paragraph as giving anestimate of the plutonium contents in all 315 containers, although a small doubtremains that what is meant is not an estimate of the total contents but of the actualplutonium contents in the 225 containers. It can reasonably be assumed, though, thatSavannah had more accurate ﬁgures on the debris that had already been processedand that they would not have used the word ‘estimate’ if those were the ﬁgures thatwere meant here.Additionally, considering that we are high up in the bureaucracy, the mostlikely conclusion is that they are interested in aggregate numbers, not partialresults.We have thus chosen the former interpretation, which we think is the more convincing.The ﬁgures are very close to those agreed between Danish and American scientistsafter on-site measurements in Thule in 1968.It is, in other words, of only marginal signiﬁcance whether we use these ﬁgures orthe on-site estimates in our calculation of the total plutonium burden in Chapter 5and the appendices.The Savannah ﬁgures serve both as a conﬁrmation of the original on-site estimates ofthe plutonium spread on the ice and snow pack, and of the fact that this plutoniumhad been brought back to the United States.Still, it would be relevant to have access to Savannah’s final report with themeasurements of the actual plutonium content in the debris from all 315 containersonce the process had been completed around 1 September 1969.

In order to illustrate what can happen to nuclear weapons in an accident, wehave found it useful to bring in a few facts about the Palomares accident. In somerespects the accidents are similar in that they involved the same type of plane andthe same kind of bomb. But there are diﬀerences as well. In Palomares, the bombswere released from the plane before the crash, some of them with their parachutesunfolded, whereas in Thule the bombs were in the aircraft when it crashed. In Thule,parts of the bombs were exposed to the large-scale ﬁre of jet fuel, whereas this wasnot the case in Palomares.There had been nine nuclear accidents before Palomares in which the high explosive(HE) in the weapons exploded. However, the contamination from these earlieraccidents had been low in radioactivity and highly localized in the areas aﬀected. Allthese accidents stimulated the development of an insensitive high explosive (IHE),which possesses a unique insensitivity to extreme, abnormal environments, and ofﬁre-resistant pits (FRPs) designed to reduce further the likelihood of plutoniumdispersal in ﬁre accidents (Gregory 1990: 32; Drell and Peurifoy 1994: 298-9, 301,306-11; OTA 1993).IHE can be impacted into rigid targets at velocities exceeding 1500 feet/secwithout provoking the release of considerable chemical energy. Traditionalexplosives release most of their chemical energy on impact at velocities in theorder of 100 feet/sec. It is generally assumed that the detonations in Palomareswould not have occurred if the warheads had been equipped with IHE. Thisnew type of explosive was ﬁrst introduced into the stockpile in 1979 (Drell andPeurifoy 1994: 308-9).20 January 1966, doc. 1-6-4995. Cable to, among others, Sandia. Preliminaryreport of nuclear accident.In this preliminary report, we learn about the three weapons that were found onland. The last bomb was later recovered from the sea bottom in a high priorityoperation.The ﬁrst weapon was found to be ‘bent but intact’. The second and third were‘badly damaged. Their secondaries are broken open [and] the primaries are virtually99

TheReport Broken Arrow, Palomares, Spain,on http://www.dod.mil/pubs/foi/reading_room/133.pdf, has the following account of the three weapons on land.Weapon no. 1.This weapon was essentially intact. The tail closing plate tore oﬀ duringbreakup of the B-52, thereby deploying the pilot chute. The bomb nose had a 9-inchgash and was depressed slightly inward from impact. Three of the four ﬁns were tornaway. The ready-safe switch was found indicating ‘Safe’. The weapon loading lugswere still engaged in the release rack mechanism.Weapon no. 2.The high explosives (HE) had experienced a low-order detonation.The bomb secondary was found in s crater about twenty feet in diameter andsix feet deep. A damaged but intact reservoir was found 25 feet from the crater.The broken afterbody and parapacks were found about 100 yards from theimpact point. The Mild Detonating Fuse (MDF) had functioned, presumably100

on impact, and the pilot chute was [unreadable word]. The main chute was outof the ruptured afterbody case; however, it was still in the chute bag. Firingcomponents and quantities of unburned HE were recovered in small pieces. Therewas plutonium contamination in the area. No tritium indication was obtainedwith the T-290 tests.Weapon no. 3.The HE in this weapon also experienced a low-order detonation.Quantities of unburned HE were recovered. The secondary was in a crater whichmeasured about [unreadable ﬁgure] feet in diameter and 3 feet deep. The smashedreservoir was found 500 yards from the impact point. The afterbody was fairly intactwith the main chute inside. The tail cover plate had apparently been torn oﬀ duringbreak up of the aircraft and the pilot chute deployed. The pilot chute was partlyburned, allowing this weapon to descend faster than No. 1. There was plutoniumcontamination in the area.Supplementary information about the weapons involved in Palomares can befound in a short article by the Engineering and Analysis Division, Directorate ofNuclear Safety, in USAF Nuclear Safety, September – October 1966 (Broken ArrowAftermath. 1966: 2-6).For our purposes, the ﬁrst remarkable feature about the Palomares accident is the fateof weapons no. 2 and 3, which experienced a low-order explosion of only parts of theHE. In both these cases, the primaries were virtually destroyed and the uranium 235and plutonium 239 of the primary pits dispersed in particulate form, as witnessedby the pattern and intensity of the contamination.It has been shown in experiments and in the literature that, after accidents involvingexplosions and ﬁre, the ﬁssile material in the pit of the primary stage will be dispersedin a particulate form. In a release of this kind, the particle size will be lognormaldistributed, i.e. the relatively few large (hot) particles will carry the majority of themass (activity). One consequence of such a release is that the activity distributionwill be very heterogeneous, but it will also be very diﬃcult to do representativesampling (Eriksson 2005).We consider the agreement between the circumstances and the particle studies inPalomares and Thule to give a strong indication that the four primaries in Thuleended up in much the same way as the two exploding primaries in Palomares, thatis, that the two cases had the HE explosions in common.101

In Thule, this appears even more likely than in Palomares because the impact velocityof the weapons was much higher. Besides, in Thule we also had a large-scale ﬁre. Theexplosions in Thule were apparently high-order. Langham’s reconstruction mightpoint in the same direction (107032, 107038).The other remarkable feature about weapons 2 and 3 in Palomares is that, although theprimaries were destroyed by the low-order explosions, recovery of the two secondarieswas possible, albeit in a broken or damaged state. In particular, we may note that thetail section of the weapon with the parapack and the tritium reservoir seemed to bea weak point in the construction.The recovery operation in Palomares was on an inﬁnitely larger scale than theunderwater operation in Thule (see doc. 107036, annex 1). This fact serves as yetanother very good indication that the underwater operation in Thule was not abouta nuclear weapon, a bomb, but something much smaller and less important.In Palomares, perhaps more than 100 scuba divers searched the shallower parts, a cubsubmarine took the medium depths, and two-manned underwater craft, one calledAlvin and the other Aluminaut, searched the deep water. The weapon was locatedsome three weeks later by the Alvin. Once the weapon was located, a new unmannedunderwater vehicle, the Curv, was used. The Curv was completely automated, withlarge crab-like pinchers, TV cameras and ﬂoodlights. The bomb was recovered on 7April 1966, 80 days after the accident (doc. 107036).

Estimates of recovered weapons partsA total estimate of recovered weapons parts is not available because most of the relevantdocuments are still classiﬁed or sanitized. Yet, for our purposes some important dataand interpretations can after all be squeezed out of the accessible sources.We will not attempt in this chapter to present a list of the recovered weaponscomponents that we have been discussing in the preceding pages. Instead we willconcentrate on some features that stand out as particularly important in this regard,such as parts recovered, parts not recovered and questions of interpretation. We willdiscuss these features in the following order, dictated by the three main sections ofthe weapons: tail end, secondary, and primary.In the background, behind this analysis and, we think, in most cases mercifullyhidden from the reader’s eye lies a combination of various methods, for instance,analyses of the decision-making in Copenhagen and Washington; analyses ofthe ﬁnds and no-ﬁnds of weapons components; assessments of the type andamount of ﬁssile material in the primaries and the secondaries; a comparisonwith similar accidents, especially that in Palomares; and use of the auxiliarysciences of history on the documents, the archives, the bureaucratic process andother circumstances.The tail ends.To take the most obvious ﬁrst, it is incomprehensible that, for some yearsnow, those who have claimed that SN 78252 had come to rest on the sea bottom havefailed to recognize the simple fact that one of the vital parts of this particular bomb,the tritium reservoir, was accounted for early in the search operation and identiﬁedwith it. This piece of evidence is enough to tell us that all four weapons broke up.The tritium reservoirs were placed in the tail ends of the weapons, but served thepurpose of boosting the ﬁssion process in the primary stage of the weapons. Thistakes care of the tail end without any need to discuss the additional evidence of theparachutes to the same eﬀect.The secondaries.Let us then turn to the secondaries. Most conspicuously, we haveargued that what the Americans were looking for in the underwater operation wasnot the fabled bomb SN 78252, but the uranium 235 marshal’s baton of a secondary.103

The Star III submersible did ﬁnd an object that appeared to ﬁt the description thatwe have squeezed out of Sandia’s report (doc. 107032), but on closer inspection itwas apparently concluded that this was not the object being sought.An AEC analysis quoted in the clippings below says that 85 percent of the uraniumof three secondaries was recovered. Given the eﬀort invested in recovering preciselythe uranium 235 of the secondaries, this percentage may refer exclusively to theuranium 235 of the ﬁssile cores of the secondaries, but we cannot be sure. Someof this amount was apparently found as intact cores, some in small fragments. Wesuspect that it was not always possible to identify these pieces of uranium 235 withany particular weapon and have to keep open the possibility that it could have comefrom all four weapons.What is missing of the uranium 235 of the secondaries is in other words 15percent by amount for three weapons plus 25 percent by amount for the fourweapons taken together. But we cannot be sure that the Americans had beenable to say with absolute conﬁdence from which weapons each and every one ofthe recovered pieces had come. If this is correct, it means that they were actingon assumptions more than on undisputable certainty when they looked for awhole piece of uranium on the sea bottom, although they may have had otherindications as well that made the underwater search look promising. Dr Walskedoes not seem to have been a ﬁrm believer in the necessity and usefulness of theunderwater search.This analysis of the hunt for the secondary ﬁssile cores has many importantimplications. Let us mention only two of them. First, it goes squarely against anyidea of a search for a bomb by telling us what the Americans were really searchingfor. Secondly, by giving an indication of how badly damaged the secondarieswere, partly as a result of the explosions, it is evidence supporting the version ofevents that all four primaries were destroyed in conventional explosions, therebydispersing − and this is most important for our understanding of the accident −not only all of the plutonium in the primaries, but also the uranium 235 of thecomposite primary pits.We think that so many parts of the secondaries were recovered as to make it unlikelythat SN 78252 should not have contributed to this collection of recovered items,which in the AEC account amounted to 94 percent by weight of three secondaries,whereas in the Air Force account we are told that ‘Unnumbered parts of the bomb104

secondaries were found widely scattered. These pieces accounted for less than threecomplete secondaries.’ The poor individual who put these inconsistent sentences sideby side in the short article ‘Broken Arrow – Thule’ could not suspect the unforgivingeyes that would be scrutinizing his prose forty years afterwards. Superﬁcially thetwo sentences are saying more or less the same thing, but when taking into accountthe fact that the Air Force account calculates only the unnumbered parts, whereasthe AEC is speaking of [all?] the recovered secondary components, question marksbegin to abound.Taken literally, the Air Force account means that we should add the numberedparts to the unnumbered, and what would we have then? 99 percent or what?As we know, one of the secondaries was found relatively intact and identiﬁedby number. Pieces of two other secondaries were also identiﬁed by number.Whether the apparent inconsistency between these two estimates carries somehidden meaning or is a result of carelessness we are not able to say. Besides, itis not even necessary to solve this small riddle. The evidence is on all countsoverwhelming that all four secondaries broke up, some of them a great deal, oneof them less so.The paragraph of ‘Broken Arrow – Thule’ that we have been discussing here ends withone of those sentences that have been used by the media over the years as supportingevidence for the idea of a bomb on the sea bottom. It says: ‘No parts of the fourthsecondary have been identiﬁed’. Suﬃce it to say that this is a logical fallacy. Whenyou have four secondaries at the outset and can identify three of them with the helpof numbered parts and at the same time have a lot of unnumbered secondary partsthat you cannot identify with any of the four weapons, then it does not follow thatno parts of the fourth secondary have been found, nor that the fourth secondaryremained intact. These ‘anonymous’ parts may not be attributable to a speciﬁc weapon,but that is not the same as saying that they have not been found. They might comefrom any of the four bombs.Consider, for example, that you drop four identical glass vases over the frozen BylotSound from an airplane. Then you add a snow storm, some explosions, a giant ﬁreand a hole in the ice. You then start a very careful search for the fragments of thevases and end up recovering 94 percent by weight of three vases. A stroke of lucklets you assemble a few of the found pieces into three somewhat larger parts, noneof which ﬁt together. You have thereby established the fact that three vases havebeen destroyed.105

In front of you there is still a heap of glass debris. Despite your eﬀorts, you do notsucceed in joining any of these remaining pieces. Would you then start thinkingthat the fourth vase was still whole? Would you claim that it follows from yournot being able to assemble a fourth fragment that a whole vase exists? You might,of course, but it would be a logical fallacy. Probably nobody would make such aclaim if we exclude the unjust master who tells his servant that he has accountedfor three vases only and accuses him of having stolen the fourth. Instead, if yourpreference were to think of whole vases, you would say that it could not be ruledout that a whole vase existed somewhere.Statistically, however, it seems much more likely that some of the unidentiﬁedsecondary pieces belonged to the fourth bomb. One need only consider themany thousands of pieces of debris reported on the sea bottom to recognizehow unlikely it would be that the ﬁgure of 94 percent for three secondariescould be reached without the inclusion of parts from SN 78252, even thoughthey admittedly could not be identiﬁed with it. This was, however, not uniqueto SN 78252. As we have said, lots of bits and pieces were deﬁned as belongingto secondaries, but they could not be assigned to any special bomb and thusremained unidentiﬁed.The primaries.We have also argued that all four primaries were completely destroyedby the explosions of considerable amounts of high explosives surrounding the primarypits. The only observed debris possibly of primaries we are aware of are the four piecesof scrap found on the sea bottom, but not recovered. In Thule we have no indicationsthat any unexploded fragments of the high explosives of the primaries were found.This is yet another sign of the destructiveness of the explosions, lending furtherplausibility to the destruction not only of the primaries, but, in varying degrees, thedestruction of the secondaries as well.A lapidary but in some regards useful overview of recovered weapon parts iscontained in the short article, ‘Broken Arrow – Thule’, by the Weapon SystemsDivision, Directorate of Nuclear Safety (Broken Arrow Thule 1968), alreadycited.

the full plutonium contents of the weapons, but it could perhaps rather be understoodas an estimate of the original level of plutonium contamination in the Thule area. Wemust admit that at the outset we were skeptical about the precision of this amount asan expression of the total content of plutonium in the weapons, but gradually we havebecome convinced that the ﬁgure of 6 kg is a close approximation or a ‘rounded-oﬀvalue’, as Dr Walske put it in his energetic defence of giving this number to the Danes.This is at the low end of the real ﬁgure, which is probably closer to 7.5 kg.However, Walske’s exquisite piece of bureaucratic compromise and diplomaticcraftsmanship should not make us believe that the Holy Grail had ceased to exist.Technical speciﬁcations concerning the contents of the four bombs on the B-52were still considered ‘secret restricted data’. This was amply illustrated in a meetingat Washington in late August 1988 between representatives of the Danish NationalBoard of Health and U.S. oﬃcials. The meeting heard Danish questions relating tothe amount and character of dispersed radioactive material, especially the contentsof the bombs and the amount of plutonium in aircraft and bomb debris shippedback to the U.S. in 1968.A somewhat elated State Department oﬃcial, in a ﬂorid display of diplomaticomnipotence accompanied by melodramatic gestures, told the Danish delegationabout the chances of getting this information. They would be roughly the same, hesaid, as that all oxygen molecules in the room would concentrate in a corner underthe ceiling. Still not fully exhausted, the oﬃcial continued to declare that the StateDepartment did not consider itself to be under any obligation to answer the questionsof the Danish National Board of Health since in the American understanding this didnot represent an oﬃcial approach by the Danish government through channels.This uncompromising attitude was, however, softened up seven years later in a fewsentences in the ‘Final Response to Danish Questions’. Had these sentences been partof a newly discovered manuscript fragment of the Holy Scripture, we suspect that asolid body of exegetic literature would have sprung up around them. Representing,after all, a text not of God but of bureaucratic machinery, these sentences haveapparently not been noticed as much as they deserve.Here is what the ‘Final Response’ says. ‘At the time of the accident, the US furnished theDanish scientists with a very reasonable estimate – 6 kilograms – of the actual amountof plutonium involved in the four weapons’ (answer 2) and ‘the Danish scientists hadbeen informed as early as April 1968 that the four nuclear weapons involved in the110

Thule accident contained a total of about 6 kg of plutonium’ (answer 9). Once youare aware of these new formulations, it is quite clear that they are very diﬀerent fromthe traditional formula, which cites ‘The fact that approximately 6 kg of plutoniumwere involved in the Greenland accident’ (answer 8) (‘Final Response’ 1995).The reader will note that the drafters have been revelling in moving the word‘involved’ around in these sentences as if to discover how many substitutions andtransformations this small innocent word could undergo before completely losing itssubstance. To cover this daring game with words, the diﬀerent versions are carefullyplaced in diverse answers at a safe distance from each other.The reason for the obsessive use of the word ‘involved’ in these sentences isobvious. It is a small face-saving device meant to conceal the for a bureaucratembarrassing fact that he has changed the canonized 27 years old formula. Weshould, however, not deplore this bureaucratic needlework since the end result ishighly satisfying. Probably for the ﬁrst time in the history of the United States,an oﬃcial document has come as close as one can expect to disclosing the contentof plutonium in actual weapons. The relevant passages deserve repeating: ‘Danishscientists had been informed as early as April 1968 that the four nuclear weaponsinvolved in the Thule accident contained a total of about 6 kg of plutonium’ and‘At the time of the accident, the US furnished the Danish scientists with a veryreasonable estimate – 6 kilograms – of the actual amount of plutonium involvedin the four weapons.’Unquestionably, these endeavours must have been approved by the Director ofClassiﬁcation of the Department of Energy and deserve their rightful place onDOE’s website, along with its long lists of small things you can say about nuclearweapons (DOE 1996).One other detail stands out as well, namely the strong emphasis on the fact that thisﬁgure has been used all along since 1968. There is some truth in this, as our referenceto Asker Aarkrog’s diary shows, and it is of course equally true that the sentence ofchoice: ‘The fact that approximately 6 kg of plutonium were involved in the Greenlandaccident’ was shared with the Danish authorities and scientists in 1968. The use of‘1968’ examples in these sentences represents, we think, another attempt to createthe impression that this is all old hat and has been repeatedly declared ever since theaccident. The probably unintended side eﬀect of this strained argument is to implythat somehow the Danes are a bit slow.111

To conclude, this was a most welcome breakthrough in the American declarationsabout the amount of plutonium released in the Thule accident, and at the same timeit appears to provide supporting evidence of our interpretation of what Dr Walsketried to accomplish back in April 1968.In the end, as much as all the above may be of interest for aﬁcionados of the mazeof diplomatic language, in practical terms it appears to be a question of one or twokilograms of plutonium more or less. As to the diplomatic language aspect, OsvaldHelmuth or John Wayne probably could not have cared less.Ironically, the ingenious, broadminded compromise of Dr Walske has not had thereassuring eﬀect that was intended. In the public mind of Danes and Greenlanders,this problem continued to raise questions because some of the common referenceworks on the subject to this day operate with 6 kg of plutonium per weapon as theminimum. In four weapons this would mean 24 kg.People would then start asking questions. ‘If the authorities say that 6 kg of plutoniumwere involved and that all four weapons exploded in a conventional explosion,where, then, have the 18 kg gone?’ This has led to a perception that there might beinconsistencies between the oﬃcial ﬁgures and the real ﬁgures and that either theremight be more contamination than reported by the authorities, or conversely thatsome of the weapons were not destroyed in the accident and therefore might still bepresent at the bottom of the sea.Thus, despite many oﬃcial explanations over the years, the perception is still alivethat some undisclosed risks might exist, either in the form of a higher degree ofcontamination than reported, or in the form of still existing bombs.We are not pretending that we know exactly how many kilos of plutoniumthere were in the bombs. The issue in this report is not absolute precision, butwhether the amount is closer to reality than to fantasy. As long as some peoplewere operating with the perceived gap between 6 kg and 24 kg, the credibilitygap between government explanations and popular beliefs was not going todisappear easily.We believe that we have discovered an amount close to reality, as well as establishedsome common ground around an epicenter of about 7.5 kg, that is, 7.5 kg in theweapons and 7.5 kg released in the explosions. Approximations, of course, but close,112

which means that we can again begin to talk reality and reestablish some of the lostconﬁdence.It is therefore with a certain satisfaction that we are able in this report to present aplutonium estimate that might alleviate some of the worries and suspicions that havebeen a factor in the history of the Thule accident for more than forty years. Yet, in orderto proceed along the route of conﬁdence towards better monitoring and improvedconditions for research, we need the release of more data, for instance, concerningthe ﬁnal results of the measurements of the ﬁltrate at Savannah River, of the debrisin the igloo at Thule, of aircraft debris in general, and of the recovered weapons partsat Rocky Flats and elsewhere (cf. for instance docs. 104812 and 104813). There is nomissing bomb, but there are missing documents. Fortunately, DOE has stated thatpublic input is welcome regarding how the Department may release information oflegitimate interest to the public while maintaining control of information importantto national security (DOE 1996).The ﬁrst of the Eureka! experiences in this part of our research was the result of a simpleconsultation of the reference workWorld Inventory of Plutonium and Highly EnrichedUranium 1992,giving 2 kg in early weapons (Albright et al. 2003). Until now, manypeople seem to have operated with a ﬁgure of 6 kg plutonium per weapon, and hardlyanybody appears to have noticed that DOE declassiﬁed 4 kg in 1994 as the theoreticalminimum for modern weapons, which presumably means weapons of the 1990s. Thisinformation has been ﬂoating around freely for over a decade, at least. More thananything else, it shows how compartmentalized information has become.After that, other bits and pieces pointing in the same direction started to surface.They are presented in the ﬁrst of two tables in the appendices. The second table givesestimates and measurements of released plutonium.The second Eureka! came later. In the ﬁnal stage of our investigation, one of thosedocuments that historians like to call ‘jewels in the crown’ suddenly began to speak.The jewel in the crown in this respect was two lines with three ﬁgures in the hand-written minutes of a meeting in Washington on 5 February 1968 (doc. 107152).On the basis of these two lines, we arrived at roughly 7.5 kg of plutonium for thefour weapons.After several decades of discussion, we have established a plausible correspondencebetween the amount of plutonium 239 that was dispersed into the environment or113

impinged into the weapon and aircraft debris by the conventional explosions of theprimaries, and the amount of plutonium 239 actually contained in the weapons tobegin with.This is a breakthrough in the investigation of the accident, although achieving itis certainly not rocket science. The importance lies in the fact that the agreementbetween the ﬁgures, with its basis in independent sources as well as a tiny piece ofuncensored oﬃcial information, helps to remove grounds for doubting the oﬃcialexplanations as to what actually happened, thus creating a basis from which to startrebuilding conﬁdence. We cannot, however, provide a ﬁnal material balance. Thatis a task for the authorities and the natural sciences.

The attempt at a historical reconstruction of the events in Thule in 1968 has beenundertaken with the aim of testing various explanations of the fate of the fourthermonuclear weapons involved in the accident.For a start, it is important to notice that we are not fully informed about theweapon items that were recovered at Thule. As far as we know, none of the morecomprehensive reviews of recovered weapons parts has been released. The short,excised survey in the DoD FOIA reading room is lapidary, to say the least, butstill useful. Many portions have been deleted in the released documents. Theexcisions apparently almost uniformly have to do with weapons design, weaponsdata, communications and other classiﬁed issues.One of the most sensitive issues in the area of restricted data was the amount ofplutonium 239 in the pit of the primary stages of the four weapons. Many otheraspects of nuclear weapons design were also considered restricted data. This is stillthe case, and most people can probably see the justiﬁcation for keeping nuclear secretsclosely guarded. Yet, as we have shown, back in 1968 the U.S. Government did infact declassify– in a thinly veiled form – a ﬁgure for the total plutonium content ofthe weapons that was nearly correct.Once this ﬁgure became public, hardly anybody believed it. Apparently, the lessonto be learnt from this is that it is safe to make your secrets known to the publicas long as you release some relatively unimportant sanitized documents as well.The result of this intricate mix of openness and secrecy can lead to such levelsof confusion that nobody will take your word, especially when you are actuallyspeaking the truth.The irony of protecting secrecy in a democratic state is that secrecy tends toundermine the citizens’ conﬁdence in the very state that exists to protect themand that needs secrecy to do so. We are deluding ourselves if we think that thesubtle balance between transparency and secrecy can be clearly deﬁned and thatthe wisdom needed to administer this balance genuinely in the public interest isalways available.

What happened to the bombs?That question was the point of departure for this report. We too have experienceddisappointments in the search for the bombs. At the outset of our research, weestablished two ‘theories’ to frame our examination of the documents. They were pureconstructs meant as simple research tools to help us analyse the events. After somedrafting we had to give up this approach, as it turned out that the tools were not useful,but instead had become a burden leading to a good deal of needless repetition.However, in order that this eﬀort should not be entirely wasted, we will allow thereader a short glimpse of our misguided ﬁrst steps in the process. We called thesetools the 4 bomb theory and the 1½ bomb theory in order not to be left behind by theBBC, and we illustrated them with the icons below that show the three main parts ofthe weapons: the primary, the secondary and the tail end. The small crosses signifythat the weapons have been ‘accounted for’, that is, either destroyed or recovered.

This concludes the summary of the evidence concerning the fate of the four nuclearweapons.The argument about a ‘missing bomb’ – which, correctly put on its own premises, isactually a ‘missing secondary’ – has been put forward at regular intervals since 1987.In its later versions, it stands on two pillars: 1) that none of the unnumbered secondaryparts could be matched with bomb SN 78252; and 2) that uncertainty, rumours anda certain amount of secretiveness surrounded the Star III diving operations.Unambiguous evidence replaces the second part of the argument. We know that theAmericans were looking for the marshal’s baton. Without the support of the secondpillar, the ﬁrst pillar crumbles under the weight of its own logical fallacy and theevidence presented in this summary.

About the sourcesThe foreign minister’s speciﬁc question to DIIS was whether the 348 documentsobtained by the BBC journalist Gordon Corera in 2001 contained decisivenew information as compared with the 317 documents declassified by theDepartment of Energy (DOE) from 1986 onwards and released by DOE inSeptember 1994.No new document-based assertions about the bombs were made in 2008, and thedocumentary evidence was much the same as that released by DOE in 1994 andused in 2000 in an article inJyllands-Posten.BBC’s second assertion about withheldinformation concerning the true meaning of the bottom survey could be called ‘newnews’ as far as the extensive media coverage is concerned, but it was based on an old,well-known document that was declassiﬁed in February 1991 and formed part ofthe 317 collection of documents.Our report is primarily based on the 348 collection, that is, the same U.S. documentsthat in many cases have been declassiﬁed for nearly two decades, but additionallyit takes in a few documents from Danish and other archives. What is new in thisreport, in other words, is not so much the sources as the analysis and interpretationof mostly familiar documents.

This is an indisputable fact already because the deuterium/tritium reservoirs in thetail sections of the four weapons broke oﬀ on impact and were recovered close tothe impact point.We can provide a clear answer: there is no bomb, there was no bomb, and theAmericans were not looking for a bomb.We have found strong indications that all four primaries were destroyed in conventionalexplosions on impact. The primary is the ﬁrst stage of the bomb.The plutonium in the primaries of all four weapons was dispersed in particulate formin the explosions and the ensuing ﬁre.This is in all important respects consistent with what happened in the low-orderexplosions of the high explosives in two of the bombs in the Palomares accident twoyears earlier, and equally consistent with the consequences of this for the secondariesand for the character of the dispersed active particles at Palomares.We have argued that all four secondaries were destroyed as well, but not in all caseswith the same devastating consequences for these sections as for the primaries.

About the plutoniumThus far there has been some public disbelief that all four primaries actually exploded.This disbelief was caused by the idea of a discrepancy between the 24 kg of plutoniumthought to be needed to reach criticality in the four primaries taken together, andthe approximately 6 kg that the authorities claimed to have been involved in theaccident.Skeptics among the public would say that either all four primaries did not explode(leaving the possibility of a ‘missing bomb’) or the supposed 24 kg had notbeen accounted for properly (meaning that the contamination was worse thanadmitted).We believe that, after several decades of discussion, we have established that theamount of plutonium 239 dispersed as very small particles in the conventionalexplosions of the weapons roughly corresponds to the amount of plutonium 239actually contained in the weapons to begin with.122

This is a breakthrough in the investigation of the accident, although achieving itis certainly not rocket science. Its importance lies in the fact that the agreementbetween the ﬁgures helps to remove grounds for doubting the oﬃcial explanationsas to what happened and may mark a new beginning in rebuilding conﬁdence onthis account. We cannot, however, provide a ﬁnal material balance. That is a task forthe authorities and the natural sciences.This ﬁnding, simple as it is, was one of the Eureka! moments in our investigation.And, as sometimes happens, the solution was lying right on the doorstep. After weeksof consulting the literature and the experts in various ﬁelds without result, we ﬁnallyturned to the disarmament literature.As a reference value, this gave a ﬁgure of roughly 2 kg of plutonium 239 per weapon.After that, several other pieces of information pointing in the same direction beganto surface.The jewel in the crown in this respect was two lines with three ﬁgures in the hand-written minutes of a meeting in Washington held on 5 February 1968. On the basisof these two lines, we arrived at a ﬁgure of roughly 7.5 kg plutonium for the fourweapons.In the 1950s and 1960s, the primary pits consisted of large amounts of uranium235 and relatively small amounts of plutonium 239. The standard reference valuefor plutonium 239 in the weapons of that period is about 2 kg. In later weapons,when the amount of uranium in the pit mix was reduced, the minimum amount ofplutonium grew to perhaps 4 kg, a ﬁgure for modern weapons that was declassiﬁedby the U.S. authorities in 1994.

About the underwater search and the ‘missing component’No nuclear weapons have been left on the bottom of the sea in Thule, nor was anysecondary left in the sea. The arguments are listed in the summary of evidence, amongthem the fact that the weight of nearly three secondaries (94%) was recovered andshipped to the U.S. Many of the secondary pieces were small and unnumbered andwere found widely scattered on the ice.Reaching a ﬁgure of 94% by weight for three secondaries seems improbable underthe circumstances if pieces from only three weapons had been collected. It is123

much more likely that this ﬁgure was reached by recovering pieces from all foursecondaries.We believe that by April 1968 the U.S. authorities already had a very good idea of whathad happened to all four secondaries. If not, it would be incomprehensible how theycould ask Sandia Corporation to establish trajectories in the water of Bylot Soundfor one special, extremely well-deﬁned weapon component − only one, and certainlyfrom a secondary. This is the second jewel in the crown of the investigation.We believe that what the Americans were looking for was the marshal’s baton,the ﬁssile core of a secondary, often referred to as the spark plug. The object wascylinder-shaped with rounded ends. Its drag coeﬃcient was calculated by SandiaCorporation to be 0.6 head on and 1.0 side on. It could have been a massive rod,but it is far more likely that it was a pipe with sealed ends. The sources provideample evidence that such pieces were recovered on the ice in February and March1968, and that the hunt for the remaining pieces continued to the end of theoperation in August 1968.There is a solid body of evidence that the marshal’s baton contained uranium 235. Webelieve that the documents refer to the marshal’s baton as the ‘secondary pit’ and the‘oralloy pit’, although no experts seem to remember or know this terminology. If wesuppose that the marshal’s baton contained 8 kg of uranium 235, it would have had avolume of roughly four decilitres. A cylinder with such a volume could, for instance,be 50 centimetres long with a diameter of 3.3 centimetres, or somewhat thicker if itwere a pipe, for instance, 5.4 centimetres with a wall thickness of 1.1 cm.This is a rather small object to ﬁnd on the sea bottom, especially when we rememberthat it could have broken to pieces and might be located among thousands of otherpieces of debris. Yet, it is bigger than a spark plug in a car. We have chosen to call itthe marshal’s baton instead. The size ﬁts this description better.That an object of this size was indeed what the American Star III submersible waslooking for is demonstrated in the video footage from the dives where the claw canbe seen recovering an object ﬁtting this description. On closer inspection, the objectapparently turned out not to be the sought-after prize.Finally, we must not forget that the decision-makers and search teams could not besure that the sought-after component had survived the crash. One would assume124

that they kept an open mind for the possibility that it had been blown to pieces orcompletely destroyed in some other fashion.The BBC has exaggerated the conﬁdentiality of the underwater operations. Theseoperations were carried out under an agreement reached in a number of Danish-U.S.meetings. H.H. Koch, the Chairman of the Danish Atomic Energy Commission,understood perfectly well that the bottom survey was not a major operation.We can return to our previous answer in a more elaborate form: there is no bomb, therewas no bomb, and the Americans were not looking for a bomb. They were lookingfor the marshal’s baton. Nor were there any whole pieces of any of the primary stages,nor any whole ones of any secondary stage, nor any tail section left behind.This may be the place to quietly observe that the Danish foreign minister’s 1987statement about the dives, reproduced in the introduction, was absolutely correct.To repeat, the Americans were not looking for a bomb but for a weapons component,almost certainly a uranium 235 ﬁssile core from the secondary stage of a weapon.They were probably not at all sure if it had actually fallen to the bottom and in whatstate, nor whether it still existed. Crumbling of uranium metal in water has beenobserved in many studies. If there were something to be found, they did not ﬁnd itin the last days of August 1968.A comparison with the search for the missing bomb in Palomares two years earlierdeals a ﬁnal heavy blow to the idea of a nuclear weapon on the bottom of the seain Bylot Sound. It is obvious that the sea bottom search in Thule had an inﬁnitelylower priority than the successful search in Palomares.We derive this conclusion from an analysis of the discussions in Washington, as wellas from the very diﬀerent dimensions of the respective underwater operations. Theextensive side track sonar scans in Bylot Sound in 2003 performed by the GeologicalSurvey of Denmark and Greenland showed no signs of debris from the crash, onlyan old iron frame. The jewels were in the archives, not in the sea.

DIIS REPORT 2009:18� København 2009Dansk Institut for Internationale Studier, DIISStrandgade 56, DK-1401 København, DanmarkTlf: +45 32 69 87 87Fax: +45 32 69 87 00E-mail: [email protected]Web: www.diis.dkOmslag: Anine KristensenLayout: Allan Lind JørgensenFoto på omslag: Undervandsfartøjet Star III foran ScrippsInstitution of Oceanography, University of California, San Diego.Fartøjet blev anvendt ved 11 dykninger i Thule i august 1968.GNU Free Documentation License.Trykt i Danmark af Vesterkopi ASISBN 978-87-7605-331-4Pris: 50.00 kr. inkl. momsRapportens webside: www.diis.dk/thuleulykken med billeder,gratis download og bestilling af rapporten i bogform.

Hvorfor denne rapport?I et brev af 6. januar 2009 bad udenrigsminister Per Stig Møller DIIS om at udar-bejde en rapport om dokumenter vedrørende B-52-bombeﬂyets nedstyrtning i 1968nogle få kilometer fra Thulebasen i det nordvestlige Grønland. B-52-ﬂyet havde ﬁrebrintbomber om bord. I mere end ﬁre årtier har den oﬃcielle amerikanske og danskeforklaring vedvarende været, at alle ﬁre atomvåben blev ødelagt ved ulykken.Udenrigsministerens initiativ skyldtes en debat i Folketinget om et par programmerog artikler, som BBC havde bragt den 10. og 11. november 2008. Syv år tidligere, i2001, havde BBC-journalisten Gordon Corera modtaget 348 dokumenter om Thu-leulykken fra det amerikanske energiministeriums (DOE) arkiv i Las Vegas.Gordon Corera er sikkerhedspolitisk medarbejder ved BBC News. Han dækkerterrorbekæmpelse, atomvåbenspredning og internationale sikkerhedspolitiskespørgsmål for BBC TV, Radio og Online. Han har beskæftiget sig indgående medbritisk og amerikansk efterretningsvæsen og har arbejdet som udenrigspolitisk kor-respondent for det britiske Today-show. Han er forfatter til en udmærket artikel‘The Need for Context: The Complexities of Foreign Reporting’. Han er bl.a. ud-dannet på Oxford og Harvard og blev ansat på BBC i 1997. Det ser lovende ud.En journalist med udmærket uddannelse og stor erfaring, 348 dokumenter og syvår til at undersøge sagen.Desværre levede resultatet ikke helt op til forventningerne. Man må spørge, omGordon Corera mener, at den historiske ‘sandhed’ udelukkende kan udledes afengelsksprogede kilder. Hovedpåstandene i artiklen var, at der kun kunne gøresrede for tre af de ﬁre kernevåben om bord på B-52-ﬂyet, således at der måske sta-digvæk lå en bombe i bugten ud for Thule, og at amerikanerne havde tilbageholdtoplysninger om det virkelige formål med en undervandsundersøgelse, som blevforetaget af et lille undervandsfartøj i sommeren 1968, nemlig at lede efter deleaf en bombe.Den første påstand om bomben var en gammel nyhed, som havde været bragt idanske medier første gang i 1987 og i en ny version i 2000. 2000-versionen byggedepå dokumenter, der var blevet afklassiﬁceret i maj 1988 og et dokument, som varafklassiﬁceret i november 1995. Den anden påstand om, at der var tilbageholdt op-133

lysninger vedrørende det egentlige formål med undervandsundersøgelserne, kan mankalde en ny nyhed, for så vidt angår omfattende mediedækning, men den byggedepå et gammelt, velkendt dokument, der var blevet afklassiﬁceret i februar 1991 ogindgik i 317-dokumentsamlingen, som nævnes nedenfor. Vi kan ikke se noget tegnpå, at Gordon Corera har arbejdet i danske arkiver eller har prøvet at veriﬁcere ellernuancere sin påstand om, at Danmark blev forholdt enhver oplysning om formåletmed undervandsundersøgelsen.Udenrigsministerens speciﬁkke spørgsmål til DIIS var, om de 348 dokumenter (ca.2.000 sider), som Gordon Corera havde modtaget i 2001, indeholdt afgørende nyeoplysninger sammenlignet med de 317 dokumenter, der var blevet afklassiﬁceret afdet amerikanske energiministerium (DOE) fra 1986 og frem og gjort tilgængelige iseptember 1994. Foreningen af Stråleramte Thulearbejdere havde bedt om adgang tildokumenterne, som også blev sendt til den danske regering efter anmodning.De 317 dokumenter, der blev gjort tilgængelige i 1999, udgør en del af de 348 doku-menter, som Gordon Corera modtog i 2001, med kun små variationer. 348-samlingenrummer imidlertid nogle få vigtige dokumenter, som ikke ﬁndes i 317-samlingen,men disse dokumenter er ikke blevet brugt i Gordon Coreras udsendelser og artikler.Man kan sige, at BBC’s bombepåstande er identiske med dem, der fremkom i august2000, og som dengang ﬁk bred omtale i danske og internationale medier, f.eks. iJyl-lands-Postenden 12. august 2000 ( J-P 12/8 2000) og af BBC den 13. august 2000(BBC News 13/8 2000).BBC Radio World Service gik endog et skridt videre og påstod, at: ‘En BBC un-dersøgelse […] har for første gang bevist, at rygterne om en mistet bombe er sande’(BBC World 2008). Ikke nogen lille bedrift. ‘All his geese are swans’, som ordsprogetlyder. BBC Two Newsnight var på samme kurs og forklarede, at: ‘The US abandoneda nuclear weapon beneath the ice in northern Greenland following a crash in 1968,a BBC investigation has found’ (BBC Two 2008).Påstande om ‘bomben der blev væk’ har en lang historie. F.eks. rejste udsendelser idanske medier spørgsmålet i december 1987. Den danske udenrigsminister forklarede,at det amerikanske ﬂyvevåben aldrig havde afvist muligheden af, at dele af en ellerﬂere bomber kunne være faldet gennem isen, men at det var uden for enhver tvivl, atde ﬁre bomber var blevet ødelagt ved ulykken. Han tilføjede, at undervandsunder-søgelserne, som blev foretaget i august 1968 af fartøjet Star III, havde vist vraggodsfra ﬂyet, men ingen bomber.134

Tæt sammenhængende med dette emne har spørgsmålet om plutoniumregnskabetværet, dvs. forholdet mellem mængden af plutonium i bomberne og mængden afplutonium, der blev spredt i forbindelse med ulykken. I september 1988 svaredestatsministeren på spørgsmål i Folketinget om dette emne.Ligheden mellem påstandene om en af bomberne er ikke overraskende, når det tagesi betragtning, at de hviler på næsten det samme dokumentgrundlag. Både i 2000 og i2008 brugte medierne de samme dokumenter og fortolkede et lille og identisk antalpassager i nogle få af de 348 dokumenter.Det bør imidlertid bemærkes, at der var en vigtig forskel. I BBC’s artikler og udsendelserfra 2008 havde journalisten talt med amerikanske embedsmænd og videnskabsmænd,der havde beskæftiget sig med ulykken i 1968, og de havde tilsyneladende bekræfteten del af informationerne fra dokumenterne.En af dem var William H. Chambers, tidligere vicedirektør og våbendesigner vedLos Alamos National Laboratory, som engang stod i spidsen for en gruppe, der be-skæftigede sig med ulykker, herunder ulykken i Thule (se dok. 107026 for et glimtaf hans aktiviteter). ‘Der var skuﬀelse over, hvad man kunne kalde manglende heldtil at få alle komponenter tilbage’, sagde han til BBC og forklarede logikken bag be-slutningen om at opgive eftersøgningen. ‘Det ville være meget vanskeligt for nogenanden at bjerge klassiﬁcerede dele, hvis vi ikke kunne ﬁnde dem’ (BBC News 2008;BBC Two 2008).Ifølge dr. Chambers var synspunktet, at ingen andre ville være i stand til hemmeligtat samle de følsomme dele op, og at det radioaktive materiale ville opløses i en såstor vandmængde, at det ville være uskadeligt. Andre embedsmænd, som har setklassiﬁcerede dokumenter om ulykken, bekræftede, at man havde efterladt et våben,hedder det i BBC-artiklen. Pentagon afviste at kommentere BBC’s undersøgelse oghenviste til tidligere oﬃcielle undersøgelser af hændelsen.Denne beskrivelse rejser nogle spørgsmål. Artiklen hævder, at unavngivne kilderhar ‘bekræftet, at et våben blev efterladt’. Dette kan naturligvis være en korrektgengivelse af, hvad de unavngivne kilder har sagt, men man noterer sig, at deresudsagn ikke er en bekræftelse af, hvad Chambers havde sagt, men at de taler omforskellige ting: Chambers om komponenter og klassiﬁcerede dele, de anonymekilder om et våben.

Man kan også formode, at dr. Chambers kunne have tænkt på forskellige scenarier,nemlig et, hvor det aktive materiale var blevet bevaret i ét stykke, og et andet, hvormaterialet var blevet delt i partikler eller fragmenter.Det er rimeligt at forestille sig, at Chambers har holdt to muligheder åbne i sit udsagn,den første, at de klassiﬁcerede dele var intakte, men ikke blevet fundet, den anden,at de var fragmenterede eller forvitrede og ikke længere eksisterede som dele. Og forat slå det fast: Hvad de anonyme kilder bekræftede, da de tilsyneladende sagde, at etvåben var blevet efterladt, var ikke en bekræftelse af, hvad Chambers havde sagt, menet separat og mindre konkret udsagn.BBC-artiklen fortsætter: ‘Men ulykken, oprydningen og mysteriet om den efterladtebombe har fortsat med at plage dem, der var vidner til begivenhederne dengang – ogdem, der lever i området nu – med stadige bekymringer over de miljømæssige oghelbredsmæssige konsekvenser af de begivenheder, der fandt sted dengang i 1968’.Uanset hensigten med denne afsluttende bemærkning kan den let læses som etar-gumentum ad misericordiammed det formål at understøtte de to sensationsprægedehovedpåstande.Vi ved ikke, hvorfor BBC-journalisten var syv år om at producere sit programog skrive sine artikler, efter at han havde modtaget de 348 dokumenter fra DOE.Uanset grunden, er der ikke noget spor i artiklerne af, at det var studier af dissedokumenter, der havde optaget ham i så lang tid. Det mest interessante ved hansberetning er ikke, hvad den siger om Thule, men at da denne underresearchedehistorie var blevet sendt ud i æteren, blev den spredt til tusinder af medier i heleverden på få timer. De har den alle sammen – fra Rachel Maddow Show til Tages-zeitung til Bogota: ‘Estados Unidos abandonó un arma nuclear debajo del hielo,en el norte de Groenlandia, a raíz de un accidente aéreo ocurrido en 1968, comodemostró una investigación de la BBC’.INew York Times’blog-ﬂagskib Lede citerede en af avisens journalister, redaktions-sekretær Carla Baranauckas, der har en grad fra Columbia Universitetets GraduateSchool of Journalism, interviewet med Chambers på denne måde: ‘Han sagde, atder var skuﬀelse, da eftersøgningen blev indstillet, men at antagelsen dengang var,at hvis USA ikke kunne ﬁnde den brintbombe, så var der heller ikke andre, der villekunne ﬁnde den’. Dr. Chambers havde ikke sagt et ord om en bombe. Kernevåben-spredningen havde omsider nået redaktionskontorerne påNew York Times– måskeet nyt mål for IAEA-inspektioner.136

Det uoﬃcielle motto for Lede stammer fra T.S. Eliot: ‘Immature poets imitate; maturepoets steal; bad poets deface what they take, and good poets make it into somethingbetter, or at least something diﬀerent’. Læseren vil muligvis tænke over, om det villevære en logisk fejl at konkludere, at Carla Baranauckas er en god digter.Midt i den internationale mediedækning var det kun Hans M. Kristensen, projektlederi Federation of American Scientists, der havde en anden mening. Han sagde til denitalienske kanal Panorama, at de dokumenter, han havde set, viste, at den fjerde bombevar blevet ødelagt ligesom de tre andre [‘Le carte che ho potuto studiare io dicevanoche anche la quarta bomba andò distrutta, come le altre tre’] (Kristensen 2008).På sin vis er allerede denne korte gennemgang tæt ved at besvare udenrigsministerensspørgsmål. Der blev ikke fremsat nogen nye påstande om en manglende bombe i2008, og dokumenterne var stort set de samme som dem, der var blevet frigivet afDOE i 1994, og som har været tilgængelige i København siden da, og bl.a. blev brugt iartiklen fra 2000 iJyllands-Posten.På det grundlag kunne man godt argumentere for,at der ikke var noget at tilføje til de svar, som de danske og amerikanske myndighederhavde givet i 1995 og 2000.Tæt på, men ikke tæt nok til at være et rimeligt svar på ministerens spørgsmål. Ensådan læsning af ministerens brev ville være ren formalisme. Den vigtigste grundtil det er, at der aldrig er blevet foretaget en uvildig, professionel gennemgang af depågældende dokumenter. Manglen på en sådan analyse gør det rimeligt at fremlæggei det mindste nogle elementer til en uvildig analyse af de frigivne dokumenter ogdermed måske også en kommentar til de oﬃcielle forklaringer og til de antagelser,der er blevet fremlagt i medierne i f.eks. 1987, 1988, 2000 og 2008.For mange kommer det måske som en overraskelse, at der ikke er blevet foretageten uvildig, professionel analyse. Forklaringen er sandsynligvis, at fokus i sagervedrørende Thule og den amerikanske tilstedeværelse har ændret sig gennem årene.Engang var fokus på ﬂytningen af Uummannaq-bosættelsen i 1953 i forbindelsemed opførelsen af et luftforsvarssystem på basen, så var det helbredsspørgsmål ogstråling i forbindelse med 1968-ulykken og endelig de udenrigspolitiske spørgsmålomkring Thulebasen, der blev aktuelle med oﬀentliggørelsen af det såkaldte H.C.Hansen-papir fra 1957. (H.C. Hansen var dengang statsminister).Historien om H.C. Hansen-papiret er behandlet i et stort tobindsværk, somblev udgivet i 1997 af Dansk Udenrigspolitisk Institut (DUPI). Det under-137

Hvad DIIS kan gøreDIIS kan udføre historisk forskning på grundlag af de tilgængelige dokumenter,underkaste dem et analytisk eftersyn og prøve at trække kendsgerninger udaf dem, når de synes at være tavse, eller når ord, linjer og afsnit ikke er blevetafklassiﬁceret og følgelig er blevet maskeret af den myndighed, der har frigivetdem.Så vidt vi ved, er det første gang, at dokumenterne underkastes en systematiskundersøgelse af en historiker med fokus på våbnenes skæbne. Som nævnt havdeDUPI-rapporten fra 1997 ikke dette fokus, og den byggede i øvrigt på en helt andenkildesamling, som DUPI havde bragt til veje fra et bredt udvalg af amerikanske ogdanske arkiver. DUPI-udredningen handlede hovedsagelig om årene forud for 1968,og i det omfang 1968-begivenhederne blev behandlet, var det næsten udelukkendemed henblik på ulykkens diplomatiske følgevirkninger.Denne danske forskningsindsats blev senere klart afspejlet i bind XII afForeignRelations of the United States,1964-1968 (FRUS).FRUS-seriener en udgivelse afoﬃcielle dokumenter om større amerikanske udenrigspolitiske beslutninger ogdiplomatisk aktivitet. Serien, der udarbejdes i State Departments historiske kontor,blev påbegyndt i 1968 og omfatter nu over 350 bind.DIIS kan gøre det, som historikere er uddannet til, nemlig prøve at rekonstruereog forstå en kæde af begivenheder i fortiden. DIIS kan imidlertid ikke undersøgedokumenterne med ingeniørers, fysikeres, lægers eller andre fagfolks øjne.DIIS har ikke ekspertise inden for kernefysik, stråling eller andre af den slags vi-denskabsgrene, og følgelig vil vi holde os fri af disse områder og kun beskæftige osmed det hjørne af begivenhederne, der kan beskrives som bombernes skæbne. Deter imidlertid ikke et isoleret hjørne, men et område, der har betydning for andreaspekter af problemkomplekset.138

Nogle få indledende bemærkningerSom nævnt har det lige siden 1968 været den oﬃcielle forklaring, at de ﬁre kernevåbenblev ødelagt ved nedstyrtningen. I ﬂere henseender synes de modtagne dokumenterved første øjekast at støtte den oﬃcielle forklaring.F.eks. rapporterede SAC Disaster Control Team i en tidlig rapport af 27. januar 1968– kun seks dage efter styrtet – at ‘på grundlag af serienummererede komponenter, somer fundet indtil i dag, er der overbevisende tegn på, at det konventionelle sprængstofi mindst tre sprænghoveder er eksploderet på eller over isens overﬂade. Denne kon-klusion bygger på placeringen af faldskærmene fra de ﬁre våben, tre tritiumﬂaskerog dele af tre forskellige secondaries fra våbnene’ (dok. 107132). Dokumentet blevafklassiﬁceret allerede i 1988.Vi har valgt dette tidlige citat med vilje for ikke fuldstændig at tage spændingen udaf fortællingen i denne undersøgelse. Citatet levner stadig plads til nogen tvivl omden fjerde bombes skæbne.Denne indledende iagttagelse vil dog ikke distrahere os fra hovedopgaven. Som forklaretnedenfor er formålet med denne rapport at foretage en uvildig bedømmelse af begivenhe-derne på grundlag af de modtagne dokumenter. Med tanke herpå vil vi holde døren åbenfor enhver forklaring, der med nogen rimelighed kan understøttes af dokumenterne.

Hvad vi forventer at opnåVi håber, at en grundig undersøgelse af de amerikanske dokumenter vil give en bedreforståelse for de vanskeligheder, der står i vejen for fortolkningen af dokumenter, hvorinformation, som måske er af betydning for den fulde forståelse af begivenhederne,i mange tilfælde er maskeret.Vi vil gøre vores bedste for at give en forestilling om indholdet af dokumenternesmaskerede dele og på den måde give et sammenhængende billede af formålet medmaskeringerne.Vi er ikke sikre på, at det vil være muligt på grundlag af maskerede dokumenter atgive et deﬁnitivt svar på de spørgsmål, der interesserer oﬀentligheden. Alligevel håbervi, at selv mindre deﬁnitive overvejelser om karakteren af disse spørgsmål vil havenogen værdi. Hvis det skulle vise sig, at vi er i stand til at opnå mere, vil det være enbehagelig overraskelse.139

Før vi går i gang med den detaljerede undersøgelse, bør det nævnes, at nogle af degrundlæggende facts om ﬂyet, bomberne, nedstyrtningsstedet, havbunden og under-vandsfartøjet kan ses i faktabokse i appendikset.Endvidere kan et Excel-ark med de grundlæggende data for alle dokumenter i 348-samlingen downloades på DIIS’s website. Det indeholder uddrag fra nogle af doku-menterne, og de dokumenter, som vi har fundet af særlig interesse for denne rapportsformål, er markeret med en farvekode. Dokumenterne kan sorteres på forskellig mådeefter forfatter/udstedende myndighed, efter udstedelsesdag, i nogle tilfælde endogefter timer og minutter, efter afklassiﬁceringsdato etc. På rapportens webside er derogså en samling billeder fra dykningerne i Thule.

Ud fra den antagelse, at fortolkningen af, hvad der skete med kernevåbnene, måformodes at have ændret sig under den lange eftersøgnings- og oprydningsoperation,vil vi foretage en kronologisk ordnet analyse af nogle af nøgledokumenterne. Dettetjener som et enkelt første lag af beskyttelse imod den forvirring, som let opstår,hvis man læser dokumenterne i tilfældig orden. Det må formodes, at en kronologiskoversigt også vil føre til nye indsigter i udviklingen af tænkningen under operationeni Thule.Efter den kronologiske gennemgang foretager vi en sammenligning med Palomares-ulykken i 1966, der omfattede den samme ﬂytype og de samme kernevåben som iThule to år senere. Palomares er en landsby på Spaniens sydøstlige kyst.Derefter opsummerer vi, hvad vi har fundet ud af om de bjergede våbendele og givernogle yderligere oplysninger fra andre kilder. Og endelig sammenfatter vi iagttagelseraf relevans for plutoniumregnskabet.Læseren indbydes til en kort tur gennem de maskerede dokumenter for at se, om derummer ﬂere oplysninger, end det hidtil har været antaget. Desværre har de mangemaskeringer i dokumenterne den uundgåelige konsekvens, at det er nødvendigt meden hel del konjekturer i løbet af analysen. Det må vi bede om læserens forståelse for.Det har vist sig, at vi kunne være fortsat i månedsvis med at prøve at løse de maskerededokumenters krydsordsgåder, men vi har været forsigtige med ikke at trække ﬂereveksler på læsernes tålmodighed, end vi allerede har gjort.Efter at de forskellige elementer er samlet, foretages der til sidst en systematisk be-dømmelse af materialet, og rapportens konklusioner fremlægges. Rapportens sigte ogperspektiv er begrænset i den forstand, at den hovedsagelig bygger på 348-samlingen,dvs. amerikanske dokumenter, som i mange tilfælde har været afklassiﬁceret i næsten toårtier, men derudover benytter den et mindre antal dokumenter fra danske og andrearkiver. Den drager fordel af de få dokumenter, der er nye i 348-samlingen sammen-lignet med 317-samlingen, ligesom den i mindre omfang inddrager dokumenter i ensamling, som blev overdraget til den danske regering i 1988 og afklassiﬁceret i 1994.Endelig er det måske på sin plads med nogle få bemærkninger om terminologi. Or-dene ‘deletion’ og ‘excision’ kan bruges valgfrit og betyder maskering eller maskerede141

dele. Et ‘sanitized’ dokument er et dokument, hvor nogle af elementerne er blevetmaskeret, altså ‘deleted’ eller ‘excised’ og fremstår enten som sorte bjælker eller hvidehuller i den resterende tekst. ‘Redacted’ er et andet ord i jargonen for ‘sanitized’. Et‘partially redacted’ dokument kan efter en ny vurdering blive bedømt som ‘releasable’,dvs. at det kan gøres tilgængeligt. De maskerede dele kan betegnes som ‘withheld’eller ‘exempt from declassiﬁcation’. Det samme sker med hele dokumenter, som sårepræsenteres i de tilgængelige arkivfoldere ved et ‘withdrawal sheet’, der løseligtidentiﬁcerer det ‘withheld’ dokument. På dansk ville man sige, at det pågældendedokument er fristforlænget, at det er udtaget og ikke tilgængeligt.Når et dokument er blevet ‘declassiﬁed’, er det ikke automatisk tilgængeligt. Førstskal det igennem en ‘release’-proces, der kan indebære en gennemgang af dokumen-tets informationer med henblik på bl.a. privatlivshensyn, retshåndhævelse og andrehensyn.En mere generel bemærkning, som ikke er møntet på nogen speciﬁkke lande, er, atvisse klassiﬁcerede dokumenter kan være fuldstændig skjult for historikerens øjne idokumentsamlinger, hvis eksistens man end ikke ville drømme om, eller i arkivenhedermed mærkelige navne, der er valgt bevidst for at skjule det virkelige indhold.

Dokumenterne i 348-samlingen er fulde af gentagelser, da de afspejler forskelligefaser af kommunikationen mellem mange aktører i det system af organisationer ogmyndigheder, der tog sig af ulykken i Thule. I den henseende er dokumentsamlingensom en kinesisk æske. Startpunkt for en væsentlig del af den korrespondance, somer repræsenteret i samlingen, var general Hunzikers Strategic Air Command (SAC)Disaster Control Team, der efter ulykken var blevet ﬂøjet til Thule med kort varselfra SAC’s hovedkvarter på Oﬀuttbasen ved Omaha, Nebraska.Både dansk og amerikansk personel blev mobiliseret efter ulykken, bl.a. fra over 70amerikanske myndigheder, herunder elementer fra the Department of Defense, theAtomic Energy Commission (AEC), State Department, Los Alamos Scientiﬁc Labora-tory og Lawrence Radiation Laboratory. Der blev regelmæssigt skrevet indberetningerog briefs til the Chief and Vice Chief of Staﬀ of the Air Force (CSAF), CINC SAC,Secretary of the Air Force, Joint Chiefs of Staﬀ ( JCS), og forsvarsministeren.Nogle af de bedste og klareste sammenfatninger af den information, der blevfremsendt gennem kommandosystemet, blev skrevet i brigadegeneral EdwardB. Gillers kontor. Han var chef for afdelingen for militære anvendelser i Atom-energikommissionen (AEC), hvorfor hans memoranda fortrinsvis var bestemtfor kommissionens formand og øverste chefer. Formanden var kemikeren GlennTheodore Seaborg, der i 1951 havde modtaget en delt Nobelpris for opdagelsenaf plutonium i 1941.Her begynder så rejsen gennem dokumenterne. De første sider af den kronologiskegennemgang har vi reserveret til en mikroanalyse af dokumenter, som dækker de førsteti dage efter ulykken – netop de dage, hvor de måske vigtigste våbenfund blev gjort.Ikke i forventning om, at dette vil føje noget særlig nyt til vores viden om ulykken,men fordi det kan give en vis indsigt i karakteren af den hemmeligholdelse, der omgavdele af ulykken, i naturen af de oplysninger, som de maskerede dokumenter søger atskjule, i, hvor eﬀektive maskeringerne er som redskab til at skjule oplysningerne, samti, hvor grundig den gennemgang af dokumenterne, der er foretaget af det amerikanskesikkerhedspersonale (security reviewers), har været.Senere i den kronologiske gennemgang fokuserer vi på grupper af dokumenter, derbehandler særlige aspekter af operationen i Thule, f.eks. bjergning af ﬁssilt materiale143

fra secondaries, undervandsoperationen, og diskussionerne mellem beslutningstagerei København og Washington.22. januar 1968, dok. 107145Dokumentet er en statusrapport for ulykken i form af et memorandum fra briga-degeneral Giller til formanden for den amerikanske atomenergikommission, GlennSeaborg, og de nærmeste chefer. Dokumentet blev afklassiﬁceret i 1988 og er identiskmed dok. 75943 bortset fra en mindre forskel i maskeringen.Giller skrev ti af disse statusrapporter i perioden frem til 10. september 1968. De giveret bekvemt overblik over begivenhederne, som de udspillede sig i USA og Grønland.De er lettere at arbejde med end de mange spredte telegrammer.Dette er den første dag efter nedstyrtningen. I teksten hedder det, at der ikke havdeværet rapporteret om eksplosioner som følge af ulykken. Vurderingen var, at bombernevar blevet liggende i bombestativet og var sunket med ﬂyskroget. På rapporterings-tidspunktet var de ﬁre våbens placering og tilstand imidlertid stadigvæk ukendt.

Når man tager kulden og mørket i betragtning, kunne man næppe forvente, at de førsterapporter skulle være præcise. Denne rapport blev da også dementeret allerede dagenefter. Dokumentet fortæller, at der ikke var blevet observeret eller hørt nogen detona-tioner af det højeksplosive sprængstof i våbnene. (Dette modsiges af andre rapporter).Forfatteren var dog allerede på dette tidspunkt klar over, at der var slået hul i isen.I dubletten af dokumentet, dok. 75943, der blev afklassiﬁceret to år tidligere, i 1986,er de første tre og en halv linje af sidste afsnit i ovenstående klip maskeret. Dette erden første, men ikke den sidste inkonsistens, vi ﬁnder i sikkerhedsgennemgangen afdokumenterne.144

Forud for det sidste afsnit er der desuden i begge versioner maskeret yderligere eneller to linjer. Den mest komplette af de to versioner giver mulighed for at gætte på,at de linjer, der er slettet i begge versioner, rummer en beskrivelse af de ﬁre kernevå-ben, som man ved var af typen Mark 28, den samme som ved ulykken to år tidligerei Palomares på den spanske sydøstkyst.23. januar 1968, dok. 107144En foreløbig rapport fra SAC’s Disaster Control Team rummer en liste over våben,sikringer og faldskærme indblandet i [maskeret]. Det siges, at der var tegn på, atet eller ﬂere af våbnene var sprængt i stykker af en højintensiv detonation af dethøjeksplosive sprængstof, ligesom dele af dem kunne være gået fuldstændigt igen-nem isen.Tanken om en højintensiv detonation af det højeksplosive sprængstof afspejlermuligvis, at der i begyndelsen ikke var gjort nogen, eller kun meget få fund afvåbendele. En højintensiv eksplosion plus et hul i isen kunne på dette tidspunktvære en måde at forklare det måske magre udbytte af de første søgninger eftervragdele af våbnene.På et møde den 25. januar 1968 i Atomenergikommissionen i Strandgade i Københavngav dr. Carl Walske, rådgiver for den amerikanske forsvarsminister i atomspørgsmål(Assistant to the Secretary of Defense for Atomic Energy), sin version af, hvad manvidste om bombernes skæbne i denne tidlige fase.Han meddelte, at det var muligt, at ladningerne af højeksplosivt sprængstof vardetoneret i et eller ﬂere af våbnene. De foreliggende oplysninger tydede på, at en afbomberne var detoneret, og at dette havde forårsaget plutoniumforurening. Ingen afde ﬁre bomber var blevet fundet, men de ﬁre faldskærme, der var fastgjort til bom-berne, var alle blevet fundet i større eller mindre afstand fra nedstyrtningsstedet. Treaf faldskærmene bar ikke spor af eksplosion eller brand, mens en, der var fundet ca.300 meter fra nedfaldsstedet (de andre var nærmere), var tydeligt mærket af brandeller eksplosion.Walske sagde, at man således kunne konstatere, at den ene bombe måtte være be-skadiget, mens de tre andre muligvis var intakte på isen, i isen, eller på havbunden;det kunne ikke udelukkes, at en eller ﬂere af de sidstnævnte bomber også var blevetbeskadiget; der var fundet metalstykker, måske fra en bombe, nær nedstyrtnings-stedet (AEK 26/1 1968).145

25. januar 1968, dok. 107138Et telegram fra SAC’s Disaster Control Team rejste en række spørgsmål, hvoriblandt:‘Hvis nogle af våbenkomponenterne beﬁnder sig på havbunden på ca. 200 m vand,hvordan kan de så ﬁndes og bjerges?’.25. januar 1968, dok. 107139SAC’s Disaster Control Team antog, at en undervandsoperation kunne blivenødvendig. På rapporteringsdagen og den følgende dag begyndte man imid-lertid at bjerge våbendele på isen, og tankerne om en undervandseftersøgningblev foreløbig lagt til side til fordel for overﬂadeoperationens mere presserendebehov.26. januar 1968, dok. 107137Klippet nedenfor er fra en telex sendt af SAC’s Disaster Control Team om opera-tionerne den 25. januar.Vi hører, at to genstande af ca. 60 cm’s længde og 25 cm’s bredde er blevet fundet 3,2 kmsydsydvest for nedslagsstedet 275 m fra hinanden og er blevet foreløbigt identiﬁceret.Hele afsnittet handler tilsyneladende om våbendele. Vi slutter af andre dokumenter, atde to genstande var blevet tentativt identiﬁceret som yderbeklædning af secondaries,og at de ikke var blevet matchet med noget speciﬁkt våben (dok. 107121). Da de eraf samme størrelse og ligger 275 m fra hinanden, er det nærliggende at antage, at dekommer fra forskellige våben.

at den angivne placering stemmer med fund af dele af secondaries, som er markeretpå en skitse af ulykkesstedet i kapitel 5.Imidlertid har vi allerede afsløret fundenes identitet. Hvis vi regnede med, at det villeforblive skjult på grund af maskeringen, tog vi fejl. Som et eksempel på inkonsistentmaskering afsløres identiteten i f.eks. dok. 107132 af 27. januar, der opsummerer fun-dene de foregående dage (se nedenfor), og nogle få dage senere, i dok. 107121 af 30.januar, kommer svaret på vores spørgsmål endnu en gang. Endelig skriver luftvåbnetsstabschef i sin rapport nr. 4, dok. 107128, at disse fund er vigtige.Endvidere blev to svært deformerede T-ﬂasker fundet ved samme lejlighed. T-ﬂaskernekaldes også reservoirer i dokumenterne. Det er beholdere med tritium, der bruges tilat forstærke eﬀekten i våbnenes primaries. Det forhold, at de ﬁndes adskilt fra andredele af våbnene, er endnu en klar indikation af, at nogle af våbnene er gået i stykker.For at lette vedligeholdelse af bomberne var T-ﬂaskerne placeret i halesektionen,uden for ‘fysikpakken’, der omfatter primary og secondary.Endelig er der det maskerede stykke efter ‘[…] less valves’. Denne halve linje rum-mer næppe oplysninger om T-ﬂaskernes placering. Det er usandsynligt, at denneinformation skulle være maskeret, når den ikke skjules to linjer tidligere. Det giverto valgmuligheder. Enten er der noget, der mangler, eller der er blevet fundet nogetmere ved siden af ﬂaskerne, og det er antagelig blevet identiﬁceret ved serienummersammen med T-ﬂaskerne.Det maskerede stykke kan også indeholde en bestemmelse af ventiler til tritiumﬂa-skerne, eftersom en ventil nævnes i et følgende memorandum, dok. 107121. Det kanvi ikke vide, men hvis der er blevet fundet noget mere, kan vi næsten sikkert sige, at detmaskerede stykke ikke handler om faldskærme. De nævnes i ﬂere andre dokumenter,og oplysninger om dem maskeres normalt ikke.27. januar 1968, dok. 107130Flyvevåbnets stabschef, CSAF, informerer i sin rapport nr. 3 til JCS om nyfundnevåbendele i punkterne litra a. til h. Vi har her bevæget os et trin op ad den bureau-kratiske stige, hvor CSAF opsummerer og kommenterer de fund, som allerede errapporteret af SAC’s Disaster Control Team. Våbendelene under litra a., f. og g. ermaskeret på listen. Ved sammenligning med andre dokumenter får vi at vide, hvaddet er. Sandsynligvis de mere interessante fund. Det synes CSAF i hvert fald. Dennæste dag kalder han dem i sin rapport nr. 4 ‘vigtige fund’.147

Samlingen af fundne dele førte nu CSAF til at underrette JCS om, at alle våben måtteantages at være gået i stykker i forskelligt omfang. Endvidere tydede det indtil viderepå lavintensive eksplosioner af det højeksplosive sprængstof [ord maskeret], men dervar endnu ikke draget sikre konklusioner.Vi er nu på femtedagen efter ulykken, og et noget mere præcist billede af bombernesskæbne begynder at danne sig, selvom der stadig er usikkerhed. Til forskel fra dok.107144 af 23. januar ﬁnder undersøgerne nu tegn på lavintensive eksplosioner i stedetfor højintensive. På grund af de maskerede ord kan vi ikke være sikre på, om dennevurdering gælder for alle våben eller kun nogle af dem.Det højeksplosive sprængstof, der omtales her, er ladninger rundt om det ﬁssilemateriale i primaries. Vi har kun én kilde til mængden af højeksplosivt sprængstofi hvert våben. Den siger 250 kg. Vi ved ikke, om dette tal er korrekt (Notits 5/21968).Professor Kofoed-Hansen meddelte ved mødet i Atomenergikommissionen den 5.februar 1968, at ﬂyet ved eksplosionen var blevet sprængt i usandsynligt mange små-stykker. Ud fra et foreløbigt skøn antog man 1-5 mio. stykker af en gennemsnitsvægtpå 10-50 gram (Notits 5/2 1968). Foruden ﬂyets høje hastighed ved nedstyrtningenog den gigantiske brand i over 100 tons jetbrændstof har eksplosionen af en bety-delig mængde højeksplosivt sprængstof naturligvis hjulpet til ved den omfattendeødelæggelse.148

Udtrykket ‘ødelagt i forskelligt omfang’ sammen med antagelsen af, at der kunhavde været tale om en lavintensiv eksplosion kan måske antyde, at man havdefundet nogle større dele af secondaries på isen sammen med mindre dele.Hvis man antager, at en højintensiv eksplosion ville forrette mere skade på seconda-ries end en lavintensiv eksplosion af måske kun dele af det højeksplosive sprængstofi primaries, kunne begrundelsen for den ændrede vurdering af intensiteten af eks-plosionerne være, at der var fundet relativt velbevarede stykker af secondaries på isensiden den første vurdering. Naturligvis kan bjergning af andre bombedele også havestøttet denne nye vurdering.Der siges intet om fund af primaries eller dele deraf. Det, vi hører om deresskæbne, fremgår af udtrykket ‘low order’-detonation. Den formodede eksplosioni primaries kan forklare, at primaries ikke nævnes, eftersom der måske hverkenfør eller siden har været nogen primarydele at rapportere om. Det højeksplosivesprængstof var placeret i primaries, og de var derfor mere udsat for at blive ødelagtend secondaries.Kontamineringen på ulykkesstedet kan have givet undersøgerne en yderligere nøgletil vurderingen. De kendte sammensætningen af det ﬁssile materiale i primaries,hvor der var både højt beriget uran og plutonium. De kendte også tilstand og vægtpå de dele af secondaries, der indtil videre var fundet. Vi antager, at secondaries ikkeindeholdt plutonium, kun uran. Betydelige dele af den uran, der var i secondaries,blev bjerget under oprydningsoperationen. Vi vender tilbage til spørgsmålet omsammensætningen af den ﬁssile kerne i secondaries i gennemgangen af operationernei februar og sidenhen.27. januar 1968, dok. 107132Yderligere våbenkomponenter var blevet fundet den 26. januar. En telex fra SAC’sDisaster Control Team formulerer sig med større sikkerhed end dokumenter fra deforegående dage. Det hedder nu, at på grundlag af de fundne serienummererede delevar der overbevisende tegn på, at mindst tre sprænghoveder var detoneret i højintensiveeksplosioner. Denne konklusion byggede på placeringen af de ﬁre faldskærmspakker,tre tritiumﬂasker og dele af tre secondaries.Hermed ser det ud til, at diskussionen om lavintensive versus højintensive eksplosionervar afgjort til fordel for det højintensive scenarie. På en måde var diskussionen ligefør om det lavintensive scenarie måske overﬂødig, men den er nu alligevel nyttig ved149

at skærpe opmærksomheden om forskelle og ligheder mellem ulykkerne i Thule ogPalomares og ved at fortælle os noget om, hvor usikre vurderingerne var i den førsteuge efter ulykken.Første del af klippet rapporterer om fundene den 25. januar. Deraf kan vi slutte,at den maskerede del handler om de to stykker yderbeklædning af secondaries, dervar blevet fundet 3,2 km sydsydvest for nedslagsstedet og blevet karakteriseret somvigtige fund af CSAF.Anden del opsummerer de fund, der var blevet gjort den 26. januar. Hvad har vi i demaskerede linjer her? I selve dokumentet hører vi, at fundene var dele af seconda-ries. I sin rapport nr. 4 næste dag fortæller CSAF, at fundet består af yderligere ﬁreserienummererede våbendele.I sidste afsnit af klippet er der ét maskeret ord. Vi foreslår, at ordet segment kan væregemt bag den sorte maskering. Segmentet optog formentlig det meste af pladsen isecondaries.

Endnu var ingen dele altså identiﬁceret med den fjerde secondary. Dette blev igenomtalt i Gillers tredje statusrapport af 2. februar (dok. 318356, afklassiﬁceret inovember 1995) og fjerde statusrapport af 23. februar. Dette er fuldt foreneligtmed f.eks. Walskes meddelelse i København den 25. januar, idet Walskes udsagnomfattede hele våben og gik ud på, at der var identiﬁceret komponenter af alle ﬁrevåben.Dokument 107132, der nævner, at ingen af de fundne dele af secondaries havdekunnet matches med den fjerde secondary i denne tidlige fase af eftersøgningen, blevafklassiﬁceret i 1988 og har mindst været tilgængeligt siden 1994. Det kan såledesikke komme som den store overraskelse for nogen i dag, end ikke for BBC, at dervar problemer med at gøre rede for det fjerde våbens secondary i begyndelsen. Blevdette problem mon ved med at bestå gennem hele operationen?De oﬃcielle forklaringer står noget stærkere efter dette dokument. Det gode spørgsmållyder: ‘Hvis tre bomber tilsyneladende var blevet så svært beskadiget, hvorfor så ikkeogså den fjerde?’. Det forekommer mest sandsynligt. På den anden side rummer do-kumentet ikke noget spor af den fjerde secondary. Den kunne måske være forsvundetuskadt gennem hullet i isen. Hvis det kunne bevises eller sandsynliggøres, ville vi havesvækket de oﬃcielle forklaringer alvorligt.151

27. januar 1968, dok. 107133Denne telex fra CSAF til SAC’s Disaster Control Team indeholder svaret på detspørgsmål, som var blevet rejst den 25. januar om undervandsoperationer. Den mestlovende metode til undervandsrekognoscering, opdagelse og fjernelse af genstandefra havbunden ville være ﬂådens Curv-dykkerudstyr. Curv havde en aktionsradiuspå 150-180 m på en dybde af 180-215 m, hvis den blev anvendt fra et ankerpunktpå isen. Curv var med held blevet brugt to år tidligere ved bjergningen af en bombei Middelhavet nær Palomares.28. januar 1968, dok. 107128Dette er rapport nr. 4 fra CSAF om endnu en heldigt gennemført søgning eftervåbendele den 26. januar.

Alene på grundlag af de serienummererede komponenter, der var fundet hidtil,var der ‘overbevisende tegn på, at [3-4 ord slettet] våben detonerede på ellerover isen’, siger dokumentet. Hvis det var al den information, vi havde, ville detikke være meget, men det, vi ser her, er ikke uigennemtrængelig hemmeligheds-fuldhed, men snarere et eksempel på inkonsistent sikkerhedsgennemgang ogmaskering af dokumenterne. I dok. 107132 ovenfor har vi lige set, hvad der erbag de sorte bjælker i 107128: ﬁre faldskærmspakker, tre tritiumﬂasker og deleaf tre secondaries.Ironisk nok er det hemmelighedsfulde 107128 med dets formentlig overﬂødigemaskeringer afklassiﬁceret tre år efter det mere transparente 107132.28. januar 1968, dok. 107129CSAF bekræfter i sin rapport nr. 5 den 28. januar om eftermiddagen tilJCS, at flere våben er blevet fundet. Maskeringen medfører, at vi ikke kanvide, hvor mange våben der var blevet fundet indtil da, dvs. dele af våben.Kun, at ikke alle fire våben var blevet fundet. Men igen er dette resultatet afinkonsistent maskering. I dok. 107132 har vi allerede set, hvad der gemmersig bag de sorte gardiner: fire faldskærmspakker, tre tritiumflasker og dele aftre secondaries.

29. januar 1968, dok. 107125I rapport nr. 6 fra SAC’s Disaster Control Team hører vi om bjergning af ﬂere vå-bendele. Et helt afsnit er maskeret i begyndelsen af dokumentet. At dømme efteromfanget kan dette afsnit rumme en del vigtige komponenter. To andre beskrivelseraf fundne dele er ligeledes maskeret.Der er kun gået to dage, siden Disaster Control Team sendte rapporten idok. 107132. Flere tegn tyder på, at denne rapport i hovedsagen er en sam-menfatning og måske også en specifikation af, hvad der tidligere er meddelt.Samtidig indeholder den en oplysning om et tilsyneladende vigtigt fund,der er blevet gjort den 28. januar. Vi formoder, at det store maskerede af-snit i begyndelsen drejer sig om dette nye fund og endnu en gang om firefaldskærmspakker, tre tritiumflasker og dele af tre secondaries. Vi har ikkefundet ud af, om det nye fund af 28. januar er den relativt intakte secondary,som vi hører om i Gillers memorandum af 2. februar (dok. 318366), ellerom det er den fjerde tritiumflaske (reservoir), som vi ved blev sendt til USAden 2. februar med den første sending af bjergede våbendele, heriblandt denrelativt intakte secondary.

Bag maskeringen efter ordene ‘closing plate’ har vi måske noget i retning af ‘a portionof a weapon case 4 by 6 inches’. Den ene linje, der er slettet lidt længere nede i doku-mentet, handler formentlig om ‘weapon parts and debris’, måske inklusive den relativtvelbevarede secondary. Disse konjekturer bygger for det meste på dok. 107132.30. januar 1968, dok. 107120CSAF underretter JCS om yderligere våbenfund den 28. januar. Beskrivelsen af eneller ﬂere våbendele er maskeret. Dokumentet sender indholdet af rapport nr. 6 fraSAC’s Disaster Control Team et led højere op i kommandosystemet. Som nævnt før,dækker maskeringen måske over fundet af den relativt intakte secondary.

En af faldskærmene lå i et hul i isen på ca. 75 cm i diameter, som tilsyneladende varopstået ved, at noget havde brændt sig ned i isen. Vandet i hullet var frosset igen på etniveau 30 cm lavere end det oprindelige. Det var uvist, om den genstand, der havdeforårsaget hullet, var gået hele vejen gennem isen og ned i vandet. Se eventuelt skitsenover ﬁndesteder for større våbendele. Skitsen viser, at faldskærmene blev fundet tætved det brændte område og nedslagsstedet (kapitel 5).Endvidere nævner memoet revnerne i isen små 100 m nord for det brændte område.Isen i dette område var meget revnet og vendt op og ned. Nogle af revnerne var overen meter brede. Det var uvist, om isen var blevet brudt op af nedstyrtningen eller afeksplosionerne. På dette tidspunkt var faldskærmene ikke blevet matchet med nogetvåben. Langham argumenterede senere godt for, at den netagtige revnestruktur varopstået ved eksplosionerne.

Denne beskrivelse af isens tilstand blev bekræftet af den danske glaciolog BørgeFristrup, der ankom den 1. februar. Dr. Fristrup så straks, at isen nord for detbrændte område var frosset for nylig, og at der var vendt op og ned på isblok-kene, som var frosset fast i unormale stillinger. Fotograﬁer fra nedslagsstedetafslørede et cirkelformet mønster af revner på ca. 200 m i diameter og et mindre,cirkelformet område, hvor isen var mere ødelagt, se evt. foto i appendiks (H.D.Bruners rejserapport, dok. 107118). Senere argumenterede Wright H. Langhamsom nævnt overbevisende for, at det var eksplosionerne, ikke ﬂyets nedslag, derhavde forårsaget revnedannelsen (dok. 107038). At eksplosionerne havde haft enså voldsom virkning på isen, er endnu et tegn på den ødelæggende kraft, våbnenehavde været udsat for.30. januar 1968, dok. 107123Dette interne notat fra AEC’s militære afdeling beskriver et af de åbenlyse formålmed operation Crested Ice – at bjerge tilstrækkeligt mange våbendele til at sikre, athemmelige data ikke blev kompromitteret, og at ansvaret for nuklear sikkerhed blevvaretaget på passende vis.Man var påpasselige med, at de danske videnskabsmænd ikke ﬁk adgang til klassiﬁceretinformation om våbnene. General Hunziker havde beordret, at et stort rum skullereserveres til det danske videnskabelige hold. Derved blev danskerne holdt ude afden klassiﬁcerede traﬁkstrøm, selvom de hele tiden havde fuld adgang til generalHunziker og hans stab (dok. 107118). De samme hensyn afspejles ikke overraskendeden dag i dag i den klassiﬁkationspolitik, der regulerer adgangen til dokumenter omulykken.

Det kan noteres, at H.D. Bruner i sin rejserapport fra Thule for perioden fra23. januar til 3. februar skriver, at våbnenes plutonium var blevet oxyderet ogaerosoliseret ved eksplosionen (dok. 107118). Dette minder os dog om, at sålænge vi ikke har adgang til en fuldstændig liste over fundene, kan vi ikke heltafskrive muligheden af, at småstumper af plutonium fra primaries kunne væreblevet fundet.Bruner var en af de vigtige skikkelser i operationen. Han var vicedirektør i AEC’safdeling for biologi og lægefaglige spørgsmål.1. februar 1968, dok. 106969Telex fra CSAF til JCS. Her omtales et bjerget sprænghoved. Strengt taget for-hindrer maskeringen os i at vide, om der er tale om et helt sprænghoved eller kundele af et. Der er dog næppe nogen tvivl om, at det er den bedst bevarede del afet sprænghoved, den relativt intakte secondary, der nævnes i Gillers rapport af 2.februar, og som måske blev fundet den 28. januar.Fundet af en relativt intakt secondary betyder, at et våben er ødelagt. Bombensprimary og halesektion er henholdsvis pulveriseret og brækket af.

ud af arkivmappen i 1988. I dansk terminologi kunne man også sige, at dokumen-tet er blevet fristforlænget. I 348-samlingen er dokumentet repræsenteret ved etadministrativt referenceark.Læseren bør dog ikke fortvivle – der er trøst rundt om hjørnet. Syv år senere, veden anden sikkerhedsgennemgang (security review), blev et eksemplar af det sammedokument afklassiﬁceret med maskeringer og ﬁndes i 348-samlingen som dok.318366. Det kommer vi snart tilbage til. At opretholde hemmeligstemplingenaf dok. 106961 er måske snarere et eksempel på bureaukratisk fejlbarlighed endpå hemmelighedsfuldhed. Som det viser sig i det maskerede dok. 318366, sigerdet næsten ikke andet, end vi allerede har hørt før i andre rapporter fra 27. januarog frem. Der er således næppe nogen grund til, at dok. 106961 ikke skulle kunneafklassiﬁceres på samme måde som 318366.2. februar 1968, dok. 106962Dette er syvende rapport fra SAC’s Disaster Control Team. Den siger ikke meget,bortset fra lidt nyt om faldskærmene. Flere afsnit er imidlertid maskeret i doku-mentet, der således er et godt eksempel på, hvor meget klassiﬁceret informationnogle af disse dokumenter rummer.Maskeringerne er så omfattende, at det forekommer håbløst at spekulere over ind-holdet af de maskerede afsnit. Den bedste strategi på dette punkt i undersøgelsensynes at være at vente på en senere sammenfatning af bjergede våbendele. Somaltid, når maskeringerne er omfattende, vil det første gæt være, at der er fundetnoget vigtigt.Hvad metode angår, kunne man måske med dette dokument som eksempel sige,at det formentlig er mere vigtigt at tælle disse ‘maskerede hunde, som ikke gør’,men hvis skygger vi kan se, end det er at være optaget af det, der kan ses tydeligt,i dette tilfælde faldskærmene.Og så alligevel – det er faktisk en overdrivelse, at vi ikke kan se de maskeredehunde og høre deres gøen. Vi ved allerede mere eller mindre, hvad der ståri de maskerede afsnit, eller vi tror i det mindste at vide det. Det kan næppevære andet end det, vi allerede ved fra 107125, 107128, 107130, 107132 og318366.

Vi får også at vide, at den første sending af våbendele [ca. 1½ linje maskeret] for-ventes at ankomme til Andrews ﬂyvestation den 3. februar. Maskeringen blokererfor detaljeret viden om karakteren af denne sending, men vi får en smule mere atvide i det næste dokument.At våbenfundene blev sendt på et ﬂy, der medtog nogle af de vigtige amerikanskeaktører, var formentlig bare et udslag af praktisk logistik. Vi hører endvidere, atdette blot var den første sending af våbendele. Det betyder måske, at der allerede pådette tidspunkt af eftersøgningen var fundet ganske mange våbendele. I alt afgik dernæsten 30 sendinger med våbendele til USA i eftersøgningens første måneder.En af komponenterne i den første sending var helt sikkert den næsten intaktesecondary. Andre dele i sendingen var ﬁre bjergede tritiumﬂasker (reservoirer), enaf dem i særlig dårlig stand.2. februar 1968, dok. 318366Memorandum fra general Giller til AEC’s formand mﬂ. Dette er dokumentet, derblev omtalt for lidt siden, og som vi mener er identisk med det ikkeafklassiﬁcerededok. 106961 af samme dato. En sådan inkonsistent praksis for klassiﬁcering ogafklassiﬁcering er et normalt fænomen, som historikere, der arbejder i arkiverne,jævnligt kommer ud for. Alligevel kommer det som lidt af en overraskelse, at nøj-agtig det samme er sket med dok. 107004, der er fristforlænget og ikke afklassiﬁ-ceret, men som faktisk er repræsenteret i 348-samlingen af det meget vigtige dok.317871, der først blev afklassiﬁceret i april 1995 og således ikke var tilgængeligt i317-samlingen.Endnu mere overraskende er det, at dok. 104810 af 22. april om en undervandsef-tersøgning efter våbenrester ved Thule stadig er klassiﬁceret og taget ud af samlin-gen, samtidig med at det alligevel er repræsenteret i samlingerne af det kun svagtmaskerede dok. 107036, der blev afklassiﬁceret i maj 1988, kun nogle få månederefter beslutningen om at tilbageholde dok. 104810.161

Når man tager det enorme antal dokumenter i betragtning, der hvert år indgår i denløbende sikkerhedsgennemgang, må fejl og inkonsistenser nødvendigvis optræderet hyppigt. I realiteten er fejlagtig tilgængeliggørelse af hemmelige eller tidligerehemmelige data så ofte forekommende, at f.eks. DOE hvert år sender en rapport tilKongressen om disse tilfælde, en rapport, som måske kun udgør toppen af isbjerget,for hvordan skulle DOE egentlig være sikker på, at det selv ﬁnder alle sine fejltagelser?Hvad der er sket i det første af de to her nævnte tilfælde, er tydeligvis, at dokumenterneer blevet behandlet i forskellige sikkerhedsgennemgange med en afstand på syv år.Sådan noget sker hele tiden og er fuldstændig forståeligt. Det ville være ekstremtkostbart at undgå disse fejl. Men vi må tilstå, at det er svært at undertrykke et smil,når man læser det amerikanske svar på ni danske spørgsmål af september 1995. Et afspørgsmålene var, om det ovennævnte dok. 106961 kunne stilles til rådighed for dedanske myndigheder – om nødvendigt på privilegeret grundlag.Det amerikanske svar var, at ‘både de dokumenter, hvorfra information var tilbage-holdt, og de dokumenter, der var tilbageholdt i deres helhed, var blevet taget fremog undersøgt for at sikre, at den tilbageholdte information, enten nationale sikker-hedsoplysninger eller fortrolige data, fortsat var korrekt klassiﬁceret. Dette var enomfattende gennemgang, som blev gennemført med henblik på frigivelse. Det blevbekræftet, at al den information, der var blevet tilbageholdt som resultat af den førstegennemgang, fortsat krævede beskyttelse i henhold til atomenergilovgivningen ellerandre sikkerhedsforskrifter. Afsløring af disse informationer ville kunne skade USA’ssikkerhedsinteresser og modvirke den amerikanske politik, der har til formål at hindrespredning af kernevåben’.Ironisk nok blev en maskeret version af det efterspurgte dokument gjort tilgænge-lig kort tid efter afgivelsen afFinal Response.Det er svært at undlade en sarkastiskbemærkning om, at så meget havde situationen nok ikke ændret sig på to måneder.Måske var afklassiﬁceringen af 318366 en diskret diplomatisk høﬂighedsgestus fra enamerikansk embedsmand. Hvis det er tilfældet, skal vi naturligvis ikke undertrykkevores smil, men bare smile – og før vi glemmer det bede vore amerikanske kollegerom at lægge det fristforlængede dok. 106961 tilbage i arkivmappen blandt de tilgæn-gelige dokumenter. Ikke, at det ville give os nye oplysninger, men fordi unødvendigttilbageholdte dokumenter giver næring til vage mistanker.Den amerikanske regering erklærede som nævnt, at de stadigvæk klassiﬁceredeoplysninger krævede beskyttelse i henhold til atomenergilovgivningen eller andre162

sikkerhedsforskrifter, og at afsløring af disse informationer ville kunne skade USA’ssikkerhedsinteresser og modvirke den amerikanske ikke-spredningspolitik. Princi-pielt kan man naturligvis ikke være uenig i behovet for at beskytte både oﬀentlige ogprivate hemmeligheder, og det sker måske oftere, end folk tror, at hemmelighedernesvogtere og historikerne fra hver deres vinkel tjener den samme fælles interesse i, atdette sker ordentligt og med størst mulig gennemsigtighed. Dette er, så vidt vi kanse, også tilfældet med den dokumentsamling, vi her benytter.Når det er sagt, så holder dette idylliske billede naturligvis ikke i alle tilfælde. Vi har her seten del eksempler på, at dokumenter holdes fejlagtigt tilbage, og at maskeringer af dokumen-ter er inkonsistente. Processerne omkring hemmeligholdelse – med alle de tilbageholdtedokumenter, maskeringerne og de slettede passager – bliver hurtigt til en hvepserede,hvor det er svært at få de mange sammenﬁltrede interesser til at harmonere.For en bureaukratisk tankegang kan sproget iFinal Responsemåske synes at være eneﬀektiv måde at lukke en sag på, men det kan også få håret til at rejse sig på hovedetaf læsere, der er bekymrede for skjulte sundhedsrisici eller miljømæssige konsekvenser.De begynder let at tænke, at der må være skjult noget meget, meget mistænkeligt baghemmelighedernes slør.Det er let at forstå, at den slags fejl kan forekomme, men den tone af imperial ufejl-barlighed, som her bruges til forsvar for et menneskeskabt, fejlbarligt system, kunnemåske også selv have behov for en lille sikkerhedsgennemgang.Når det er sagt, er de mange fejl på en måde samtidig et tegn på betydelig åbenhed.Når man gør mange dokumenter tilgængelige – og det er tal i millionstørrelsen, visnakker om – bliver det hurtigt en yderst kompliceret aﬀære at holde styr på forskel-lige maskeringer, fristforlængelser og tilbageholdelser af identisk eller næsten identiskinformation spredt over forskellige arkiver og forskellige lande – og med dokumenter,der citerer hinanden, sommetider med lange intervaller og ofte uden henvisninger.Dette rammer de folk (security reviewers), der foretager sikkerhedsgennemgangen,som en veritabel tsunami.En security reviewer, der overvejer at løfte blot en enkelt sort bjælke fra et dokument,må let kunne føle sig overvældet ved tanken om de konsekvenser, det måske kunnefå for snesevis af andre dokumenter. Stillet over for den arbejdsbyrde og den risikofor fejltagelser, det kunne indebære, er den lette udvej for security revieweren atopretholde den eksisterende klassiﬁcering.163

Der er generelt ikke nogen grund til, at historikerne skal føle sig snydt eller sætte sigpå den høje hest i forhold til de arkivarer, som med henblik på åbenhed stræber efterat gøre informationer tilgængelige og samtidig beskytte private og oﬀentlige hem-meligheder. Kun når hemmeligholdelse bruges til sløring af uberettiget, fejlagtig ellersjusket tilbageholdelse af dokumenter, opstår der interessekonﬂikter.Hvis vi skal bringe disse let slyngede overvejelser til en afslutning, kan det måskevære på sin plads at minde om, at ulykker med kernevåben som den i Thule ikke ernoget, der sker hver dag. At forurene andre landes territorium med plutonium erheldigvis snarere en undtagelse. Thule og Palomares er de to bedst kendte eksemplerfra perioden.Plutoniums halveringstid er ca. 24.000 år. I 1995 kaldte USA sit svar til den danskeregeringFinal Response to Danish Questions on B-52 Crash.Men når man tænker pådet forurenende stof og begivenhedens ekstraordinære karakter, kan der næppe værenogen endelige svar eller tidsfrister. For god ordens skyld bør det noteres, at det i svarethed, at de amerikanske myndigheder var rede til at behandle supplerende spørgsmål,hvis de vedrørte nye aspekter af ulykken i 1968 (Finalresponse1995).Det, USA har gjort for at afhjælpe ulykkens følger, er godt; for eksempel fjernelsenaf forurenet is, sne og vraggods. Det, USA med rimelighed kunne have gjort mereeller bedre, men ikke har gjort, er dårligt. Det er ikke et spørgsmål, som afhænger afdenne generation alene, og som kan afgøres én gang for alle. Ny viden og nye normerkan ændre opfattelserne, fortolkningerne og prioriteterne.Noget af den hemmeligholdelse, som omgærder visse aspekter af ulykken, kan i sig selvvære en hovedårsag til bekymringer og spekulationer blandt dem, der er mest direkteberørt af ulykken, nemlig beboerne i Thuleområdet. Set i det lys er det beklageligt, atsikkerhedsgennemgangen af de amerikanske dokumenter vedrørende ulykken ikke erfejlfrit udført og ikke synes at have haft tilstrækkelig opmærksomhed fra den ameri-kanske regerings side. Det er pinagtigt at være vidne til, at unødvendigt tilbageholdtedokumenter får lov til at give næring til ubegrundede mistanker.En afklassiﬁceringsgennemgang af de dokumenter, der vedrører ulykken, kan ikkegennemføres som ren rutine i henhold til standardprocedurer, sådan som det sy-nes at have været tilfældet i denne sag. Man kunne ønske, at gennemgangen antogkarakter af et forskningsprojekt inden for de berørte amerikanske myndigheder– med den investering af tid og ekspertise, som er nødvendig for at udføre arbejdet164

ordentligt. Vi ved naturligvis ikke, hvor meget der skal til, men det er næppe nogetstort projekt.Indtil hemmeligholdelsen engang kan ophæves fuldstændigt, kunne man give højprioritet til afklassiﬁceringsgennemgange med regelmæssige mellemrum med henblikpå at fjerne forældede eller unødvendige klassiﬁkationskrav. I et memorandum harpræsident Obama erklæret, at hans regering har som mål at arbejde med en hidtil usetgrad af åbenhed, når det gælder klassiﬁceret materiale (Obama 2009). Med dennerapports emne i tankerne er det endvidere værd at bemærke, at energiminister StevenChu har gentaget og støttet præsidentens Freedom of Information Act-politik i etmemorandum til energiministeriets chefer af 5. juni 2009 (Chu 2009).Så vidt vi ved, behøver der ikke på amerikansk side at være nogen bekymring for atstøde ind i danske sikkerhedsbestemmelser eller politisk følsomme områder i dennesag. På dansk side er dokumenterne fra 1968 om Thuleulykken tilgængelige i arkiverne.Dette gælder for eksempel akterne fra Udenrigsministeriet, Atomenergikommissionenog Risø. På en række områder gør danske myndigheder og forskningsinstitutionerderes del af arbejdet, for eksempel ved monitering af plutoniumniveauet i området, påland såvel som på havbunden. Også internationale ekspertkonsortier har medvirket idenne indsats, ligesom IAEA har medvirket ved den videnskabelige kvalitetsbedøm-melse af det danske arbejde.Vi forstår af litteraturen, at den generelle viden om plutoniumforurenings konsekvenserog karakteristika, såvel som den konkrete analyse og fortolkning af moniteringsdata,vil nyde godt af, at mere præcise oplysninger gøres tilgængelige om de såkaldte kildertil det ﬁssile materiale, som blev spredt ved ulykken. Dette kunne være et gunstigtudfald, både lokalt og globalt, for kvaliteten af moderne monitering og for det al-mindelige beredskab i tilfælde af fremtidige angreb med såkaldte snavsede bomber(Vantine & Crites 2002).Men nu tilbage til dok. 318366. I dette tredje memorandum fra general Giller i AEC’safdeling for militære anvendelser til AEC’s formand mﬂ. omtales forsendelsen medvåbendele fra ovenstående dokument endnu en gang. Dette er stedet, hvor vi hører,at en relativt intakt secondary var bjerget og med i forsendelsen. De andre genstandei forsendelsen er maskeret i dette dokument i lighed med, hvad der var tilfældet i dok.106963. Den korte maskering i klippet nedenfor efter ordene ‘shipment increment’dækker muligvis blot over et par ord om portioner af to secondaries, men sandsynligvisover noget, der er en smule mere interessant.165

meget tæt derved. Imidlertid var der endnu uvished om, hvad der var sket med en afsecondaries, fordi man ikke havde bjerget dele, der positivt kunne identiﬁceres meddenne. Her er det naturligvis lige så vigtigt at bemærke, at der var fundet dele af se-condaries, som eksperterne i Thule endnu ikke havde været i stand til at matche mednoget bestemt våben. De kunne altså stamme fra et hvilket som helst af de ﬁre våben– og vel især fra de tre secondaries, der ikke var blevet bjerget i næsten intakt stand.Gordon Corera begår en analytisk fejl ved at bygge for meget på sådanne helt foreløbigevurderinger fra et tidligt tidspunkt i undersøgelserne. Det er bl.a. for at undgå den slagsfejl, at der i dette kapitel gennemføres en kronologisk organiseret undersøgelse.4. februar 1968, dok. 106960Denne rapport bekræfter, at ﬂyet var begyndt at gå i stykker før nedslaget. Vragdele,især rester af bombeluger, var blevet fundet næsten 3,2 km nord for nedslagsstedet.Disse fund var ikke radioaktivt forurenede.

Maskeringerne betyder, at vi ikke kan være sikre på, at alle fundne faldskærme bliveromtalt. De faldskærme, der nævnes i de synlige dele af dokumentet, er måske kunde uidentiﬁcerede, eftersom nogle af de faldskærme, der er beskrevet i de tidligeredokumenter, var blevet henregnet til bestemte våben. Det er muligt, at alle de ﬁrebjergede tritiumreservoirer nævnes i de maskerede dele.Hvordan det nu end forholder sig, var alle faldskærme og alle ﬁre tritiumreservoirerblevet matchet med et våben halvanden måned senere, den 19. marts. Dette afsluttermikroanalysen af de første dage af operationen. Fremtidig forskning med mere tid tilrådighed kan sikkert presse ﬂere oplysninger ud af disse dokumenter og rette nogleaf de misforståelser, som vi måske har gjort os skyldige i.

Særlige aspekter af eftersøgningsoperationerne og de dansk-amerikanske forhandlinger4. februar 1968, dok. 106959Rapport nr. 10 fra CSAF beretter, at State Departments repræsentant på SAC’sDisaster Control Team mente, at professor Kofoed-Hansen, som nu havde forladtThule for at rejse til København, medbragte en personlig rapport, som ville indeholdeoverdrevne skøn for plutoniumspredningen. Denne vurdering ramte langtfra plet– absolut ingen cigar til den mand.Det, der i virkeligheden skete, da Kofoed-Hansen kom hjem til København, var, athan gav Atomenergikommissionen et meget lavt skøn for våbnenes plutoniumindholdsammenholdt med, hvad man almindeligvis troede dengang. Professor Kofoed-Hansens168

skøn var 2 kg plutonium pr. våben. Som vi senere skal se, var det tæt på plet. Til delsvar dette skøn naturligvis baseret på det danske videnskabelige holds observationer iThule, men det er svært at tro, at han ikke også skulle have følt sin vurdering bestyrketi udvekslinger med de amerikanske kolleger i Thule (Notits 5/2 1968). Senere hørervi i et andet dokument, en rapport skrevet af det amerikanske videnskabelige holdi Thule, at de 2 kg var, hvad de danske videnskabsmænd generelt regnede med, ogat det amerikanske hold accepterede at diskutere ulykken med danskerne i det lys(Crested Ice SAC 1969, Vol. IV, Annex i).5. februar 1968, H.H. Koch-notatI et foreløbigt notat skrev H.H. Koch, formand for Atomenergikommissionens for-retningsudvalg, at dr. Kofoed-Hansen var vendt hjem fra Thule via USA. Det kanindskydes, at han på ﬂyet med den relativt intakte secondary i lastrummet kan haveudnyttet lejligheden til at fortsætte de faglige diskussioner med sine amerikanske kol-leger, dr. Bruner og dr. Langham. Kofoed-Hansen havde informeret repræsentanterfor Atomenergikommissionen, Ministeriet for Grønland og Udenrigsministeriet om,at hver af de ﬁre bomber mentes at indeholde 2 kg plutonium.

5. februar 1968, dok. 107152 (håndskrevet), sammen med 106915, 107151 and107160På samme dag som dr. Kofoed-Hansen briefede de danske myndigheder i København,gav dr. Langham og andre en lignende fremstilling i Washington, D.C., ved en fællesDOD/AEC-brieﬁng. De dokumenter, der opregnes i overskriften til dette afsnit, erformandens beretning fra det møde i AEC’s sikkerhedspanel, som fulgte umiddelbartefter DOD/AEC-brieﬁngen den 5. februar.Dokumenterne 106915, 107151 og 107160 er maskinskrevne og identiske bortsetfra nogle få ting. En af forskellene er en håndskreven note på dok. 107151, visti første klip nedenfor. De maskinskrevne beretninger er ordentlige og lette atforstå, men man bør lægge mærke til sætningen i anden linje, der siger: ‘Mødetsalmindelige indhold afspejles ikke her bortset fra et par få punkter […]’. Vi måaltså lede andre steder efter indholdet af brieﬁngen og mødet i sikkerhedspanelet.Hvor ﬁnder vi det?Før vi besvarer det spørgsmål, skal vi bemærke en anden afslørende forskel mellemde maskinskrevne versioner. Formandens beretning var allerede blevet fordelt mel-lem mødedeltagerne, da det gik op for AEC’s Director of Classiﬁcation, Myrray M.Nash, at beretningen burde tilbagekaldes, eftersom den indeholdt konﬁdentielle170

data. I overensstemmelse hermed returnerede sikkerhedschefen ved Woods HoleOceanographic Institution instituttets ‘one and only copy’ af formandens beretningefter at have klassiﬁceret den. Versionen i dok. 106915 er det eksemplar af formandensberetning, som blev tilbagesendt til AEC af Woods Hole.Lad os se på den oplysning, der havde forårsaget tilbagekaldelsen af formandens be-retning fra Woods Hole: ‘Vi har fået at vide, at [håndskrevet: minimum 38%] 38%af den samlede plutoniumbyrde beﬁnder sig på sne og is rundt om ulykkesstedet;36% af byrden ligger inden for de isopleter, der svarer til 100.000 tællinger per minut(cpm) målt med de til rådighed stående instrumenter’.

Efter den forsinkede intervention fra klassiﬁkationschefen blev denne oplysningklassiﬁceret, eftersom den tillod et direkte skøn over mængden af plutonium i våb-nene. Følgerigtigt blev hele citatet ovenfor maskeret ved sikkerhedsgennemgangen afdokumentet i 1988. Den amerikanske regerings svar i 1995,Final Response to DanishQuestions on B-52 Crash,lød, at der var gennemført en omfattende sikkerhedsgen-nemgang for at sikre, at alle tilbageholdte oplysninger var korrekt klassiﬁceret. Denneerklæring dækker også den maskering, der omtales her. For så vidt angår udsagnetom, at denne anden sikkerhedsgennemgang havde været omfattende, skal det blotnævnes, at den tilbageholdte information kan læses i fuldtekst i dokumenterne107151 og 107160.Klippet nedenfor stammer fra dok. 107152 og rummer svaret på det spørgsmål,vi stillede før. Det er en af de funklende juveler i 317- og 348-samlingerne.Læseren må gerne trække vejret dybt. Det, vi har i klippet foran os, er et lillestykke af de håndskrevne mødenotater, som refererer dr. Langhams udtalelser.171

I sin fremlæggelse forklarede Langham, hvor meget af den totale plutoniumbyrde derlå på sne og is ved ulykkesstedet. De to linjer lyder således: ‘3. Beregning af plutoniumi området efter koordinatsystem = mindst 38% (?) +40% (måske op til 54%) total’[‘3. Calculation of Pu [plutonium] in area by grid = at least 38% (?) + 40% (may beup to 54%) total’]’.Det særlige ved den håndskrevne version er, at den har tre tal, 38% (?) +40% (måskeop til 54%), mens to af de maskinskrevne versioner kun har ét tal, 38 pct. – dok.107151 som vi lige har set med en håndskrevet tilføjelse under tallet 38, der siger‘mindst 38%’, og selv dette ene tal er maskeret i dok. 106915, hvilket fortæller osnøjagtigt, hvad det var, AEC’s Director of Classiﬁcation var så bekymret over. Kunden håndskrevne version giver os den komplette nøgle til et spørgsmål, der er blevetdiskuteret, lige siden ulykken fandt sted.Blandt de radiologiske målinger, som Langham havde til rådighed for sin brie-fing, var en 13-siders rapport fra den første radiologiske oversigtsmåling, derblev foretaget langs 30 graders radialer og var klar den 1. februar 1968 (Wal-ske-Koch 15/4 1968, enclosure 1; Crested Ice SAC 1969, Annex B, AppendixIII). Også det første isodose-kort var tilgængeligt på dette tidspunkt (dok.107148, figur V). Resultatet af målingen af 1. februar blev senere bekræfteti den 20. situationsrapport fra SAC’s Disaster Control Team af 17. februar(dok. 106904), hvori man diskuterede resultatet af en radiologisk målingforetaget den 14. februar i det brændte område i et tæt koordinatsystem (med50 fods intervaller) og sammenlignede med målingen den 1. februar. Så vidten historiker kan bedømme, adskiller den første måling sig ikke fra den senerepå noget afgørende punkt. Vi finder det ganske sikkert at tage udgangspunkti denne antagelse.172

De tal, der fremlægges i den håndskrevne version, er udtryk for minimum-, median- ogmaksimumskøn for plutonium spredt på sneen og isen. For vores formål er det uden be-tydning, om disse skøn er præcise eller ej, så længe vi ved, hvad Langhams skøn i kilo var pådenne dag. Vi har brugt de sædvanlige tal for plutonium på sne og is, som man opereredemed på dette tidspunkt, hvilket vil sige 2,8 kg som minimum og ca. 4 kg som maksimum.De var udledt af de samme målinger, som Langham her støttede sig til. Det er klart, at voresarguments gyldighed afhænger af, at det var disse tal, Langham anvendte. Vi har kontrol-leret, om der er identiske forhold mellem de to sæt tal 38:54 og 2,8:4, og det er der.Udtrykket ‘den totale plutoniumbyrde’ dækker over indholdet af plutonium i våbnene.Langhams ene faste værdi var netop mængden af plutonium i våbnene. Han kendteogså værdierne i kilogram for minimum-, median- og maksimumskøn for plutoniumspredt på sneen og isen. Heraf følger, at det var let for ham at fortælle panelet udtrykti procent af bombernes indhold, hvad minimum-, median- og maksimumskøn forplutonium spredt på sneen og isen var.Og nu da vi kender disse procenter og er ret sikre på, at vi også kender Langhams skøni kilo, er det også let for os at beregne den totale mængde plutonium i våbnene, deri så mange år har været ‘den store ubekendte’, ‘Alle Hemmeligheders Moder’, ‘DenHellige Gral’. Tallet er ca. 7,5 kg.��

I ﬁre årtier har amerikanerne – samtidig med at de klart har signaleret, at de ikkekompromitterede fortrolige oplysninger – kaldt tallet 6 kg en tilnærmet værdiog et meget rimeligt skøn, og de har haft ret. Har vi så virkelig fundet ‘Alle Hem-meligheders Moder’? Nej, naturligvis ikke. Denne ‘store hemmelighed’ er blotet sediment af fortidens nødvendighed, et dogme, der engang var meningsfuldt,men som gradvis er blevet et tomt ritual. Men som altid med dogmer er det sværtat opgive dem.Samtidig har vi endnu en gang vist, at den mistænksomme embedsmand fraState Department ramte helt forbi i sin rapport af 4. februar. Vi har set, atprofessor Kofoed-Hansens og dr. Langhams vurderinger af plutonium i våb-nene og plutonium spredt ved eksplosionerne svarede ganske udmærket tilhinanden.Vi efterlader naturligvis ikke kronjuvelen her, men ser nærmere på den i kapitel 5.Her kan vi nøjes med at gentage, at dette dokument blev gjort tilgængeligt i 1994som en del af 317-samlingen, dvs. før det højtidelige sprog iFinal Response to DanishQuestions,hvor de tungnemme danskere pompøst ﬁk indprentet kvaliteten af detamerikanske system for sikkerhedsgennemgang af dokumenterne. Det har med andreord været tilgængeligt i 15 år.8. februar 1968, dok. 106940Telex om håndteringen af ﬁre (tritium)bombereservoirer fra Lee Hancock, AEC’srepræsentant i Albuquerque, til G. Stone, DMA, AEC, Washington.Det følgende citat i dokumentet stammer fra en Los Alamos-melding af 7. februar,hvori det hedder: ‘Reservoirerne nr. 1A1-14582-22, 1A1-63685-42, 1A1-63875-42og 1A1-53057-22 blev taget ud af containerne nr. JP 65711C9, JP 65273C9 og JP65547C9 i perioden 5.-6. februar 1968’.Ifølge Lee Hancocks rapport af 20. februar (dok. 106883) blev de fire (triti-um)bombereservoirer sendt fra Thule den 2. februar med den første sendingaf våbendele. Ligesom for eksempel den næsten intakte secondary havde deledsaget Kofoed-Hansen, Langham og nogle af de andre videnskabsmændpå flyvningen til USA. Vi ved altså, at alle fire tritiumreservoirer var blevetbjerget før den 2. februar og sendt til Los Alamos til yderligere identifikationog måling. Betydningen af reservoirernes bjergning og identifikation vil blivekommenteret senere.174

14.-16. februar 1968, dok. 106899, 106907, 106908Et møde over to dage fandt sted i København mellem danske og amerikanske embeds-mænd og videnskabsmænd. Plutoniumforureningens omfang blev drøftet, og mannåede en aftale om fremgangsmåden ved den videre monitering såvel som fjernelse afforureningen på sne og is. I sin opsummering af forhandlingerne kaldte Carl Walskeresultatet en ‘gentlemanaftale’.Det forhold, at forhandlingerne fandt sted på højt niveau, og at de var præget af storgrundighed, viser den betydelige omhu, der blev udfoldet for i videst muligt omfangat afbøde ulykkens konsekvenser. Det samme gør den udmærkede samarbejdsånd, derprægede forhandlingerne mellem de to parter, til trods for at deres udgangspositionerlå ret langt fra hinanden. Forhandlingerne og korrespondancen mellem parternevidner om en yderst professionel håndtering af krisen.24. februar 1968, dok. 106887Rapport nr. 27 fra SAC’s Disaster Control Team.I dette dokument følger vi nogle af anstrengelserne for at ﬁnde rester af ﬁssilt mate-riale fra våbnene. Det samme ses af dok. 106893 af 22. februar. Den 6. februar havdeman påbegyndt en særlig indsats for at lede efter især uran 235. Den særlige indsatsstrakte sig i det indledende format over en måned, men fortsatte med andre metoderindtil udgangen af august.Den anvendte fremgangsmåde viste sig nyttig til opsporing af våbenkomponenter, dervar begravet i sne og is. Daglige eftersøgninger med PRM5/SPA-3-udstyr fortsatte,indtil de generelle bestræbelser på at indsamle våbenskrot blev indskrænket i slut-ningen af marts (Crested Ice SAC 1969, Annex B). Den særlige indsats nævnes ogsåi en telex af 6. februar fra SAC’s Disaster Control Team i Thule, hvor man omtalereksperimenter med samme type udstyr for at lokalisere store kilder af uran 235 (meden indstilling på 185 keV) og plutonium (indstilling på 375 keV) (dok. 106954). Vihar ikke set nogen tegn på, at en søgning efter store plutoniumkilder skulle have givetnoget resultat. Ud fra de tilgængelige oplysninger synes denne del af operationen athave været temmelig hypotetisk.Disse daglige aktiviteter kan i en vis udstrækning følges i dokumenterne (CrestedIce SAC 1969, Annex B, Appendix I). Som nævnt var de måleinstrumenter, der blevanvendt til formålet, af typen SPA-3. Indstillingen på 185 keV viser, at holdene ledteefter uran 235 fra specielt secondaries, dvs. disse sektioners ﬁssile kerne, ofte kaldet175

‘tændrøret’. ‘A 20 pound section [en halv linje slettet] was found 8/10 of a mile southof the burn area’. At dette ikke var en hvilken som helst våbendel, ses af, at den blevhjemtaget til basen til optøning, videre identiﬁkation, pakning og afsendelse til LosAlamos.Det var en speciel behandling at sende denne del til Los Alamos, eftersom Gillernetop i sin fjerde rapport af 23. februar havde erklæret, at alle bjergede våbendeleblev sendt til Rocky Flats, undtagen tritiumreservoirerne, der blev sendt til Los Ala-mos. Dette adskiller sig fra den 30. januar, hvor Pantex omtales som den foretruknedestination for våbenskrot (dok. 107123). De respektive roller for Pantex og RockyFlats behandles igen i en rapport af 20. februar (dok. 106883).Den nævnte sektion på 20 pund (9 kg) passer på en del af en secondary på skitsen overstørre våbenfund (kap. 5). Vi tror, at denne sektion på 9 kg indeholdt den ﬁssile kernei secondary til bombe nr. 1, SN 690020, et rør af uran 235, også betegnet oralloy. Etdokument fra Directorate of Nuclear Safety siger om bombe nr. 1, at dele af dens se-condary blev fundet 1 mile og 2 miles syd for sydspidsen af det brændte område (BrokenArrow Thule 1968). Det første passer ﬁnt med placeringen af 9 kg-sektionen. Dettesammenfald beror ikke blot på lokaliteten i sig selv, men bestyrkes af, at der er tæt verbaloverensstemmelse mellem de to kilder, der angiver placeringen af ﬁndestedet.

Her bør vi måske minde læseren om, at historikerens arbejde i dette tilfælde består i atsammenstykke nogle små oplysninger fra hundredvis af uklare, maskerede kilder, og atder helt åbenbart kan gå noget galt i processen med at identiﬁcere, vælge og fortolkedisse småstykker. Men hvis vi har ret, gør belønningen det værd at tage risikoen. Hvisvi har uret, har vi måske skaﬀet de amerikanske security reviewers en god latter.Antager vi, at den fundne sektion indeholdt en hel ﬁssil kerne fra en secondary, harvi fået en del vigtige oplysninger. For det første, at 25 pct. af det ﬁssile materiale fra176

secondaries blev bjerget i dette fund, for det andet, at den ﬁssile kerne i secondariesvejede ca. 8-9 kg, for det tredje, at disse genstande blev anset for tilstrækkelig vigtigetil, at man iværksatte en særlig eftersøgning efter dem, og for det fjerde en bekræftelseaf, at de bestod af uran 235. Endvidere har vi måske fundet en dåseåbner til fortolk-ning af andre dokumenter i samlingen. Vi kan naturligvis ikke vide, om der indgiken yderbeklædning i vægten på de 9 kg.5. marts 1968, dok. 107007SAC’s Disaster Control Team, rapport nr. 42. I dokumentet konstateres det, at ‘etradiologisk hold udstyret med SPA-3 har fundet et stykke af en våbenkomponentved sydøstkanten af det brændte område. Det er nødvendigt at tø komponenten opfor at få fjernet polarisen, så den kan undersøges nærmere. [en linje maskeret]. SPA-3-eftersøgningen vil blive fortsat i samme område i morgen’.Den maskerede linje i dokumentudsnittet nedenfor registrerer sandsynligvis fundet afendnu en ﬁssil kerne fra en secondary, eller dele af en kerne, som vi mener består af uran235/oralloy. På engelsk bruges udtrykket ‘pit’ om den ﬁssile kerne i bombens førstesektion, primary. Vi tror imidlertid, at begrebet ‘pit’ også bruges om den ﬁssile kerne ibombens anden sektion, secondary, og at man for at skelne mellem de to ﬁssile kernerkunne tale om ‘secondary pit’ eller ‘oralloy pit’ i modsætning til ‘primary pit’.Denne iagttagelse grunder sig på en sammenligning med dokumenterne 107041 (12.april) og 107047 (1. april). Det faktum, at SPA-3-instrumenter nævnes både før ogefter maskeringen, siger os, at vi er midt i jagten på oralloy. Vi har ikke kunnet veriﬁcereden her nævnte terminologi i referenceværker eller i konsultationer med eksperter.Hvis den viser sig at være korrekt, skal leksikograferne i gang med en tilføjelse.

7. marts 1968, dok. 317871Dokumentet hører til et dagsordenspunkt om Thuleoperationen, som skulle drøftespå et møde i AEC. Det har to bilag, et memorandum af 6. marts fra klassiﬁkationsdi-rektøren, C.L. Marshall, og et bilag til dette memorandum, med titlen ‘ClassiﬁcationBulletin WNP-16 af 16. februar’.Som endnu et eksempel på, hvad der synes at være en inkonsistent sikkerhedsgen-nemgang af dokumenterne i 1980’erne og 1990’erne, er dok. 317871 tilsyneladendeidentisk med det tilbageholdte dok. 107004. Det maskerede dok. 317871 blevafklassiﬁceret den 26. april 1995, mens dok. 107004 blev sikkerhedsgennemgået ogtilbageholdt den 18. marts 1988.Selvom disse dokumenter stadig har store maskeringer, udgør de en glimrende il-lustration af de dilemmaer, som den amerikanske administration mødte ved hånd-teringen af de klassiﬁkationsspørgsmål og konﬁdentialitetsproblemer, der opstod iforbindelse med ulykken.

Det hedder i dokumentet, at ‘de gældende klassiﬁkationsregler foreskriver, atmængden af plutonium i et speciﬁkt våben er en hemmelig oplysning’. Hvor mangekilo plutonium var der i primaries? Det var spørgsmålet og hemmeligheden.Dette lille stykke hemmelig information var sammen med en række andre design-detaljer, hvad der i realiteten forklarede behovet for at have et lukket kredsløb forklassiﬁceret information under og efter oprydningsoperationen i Thule.Som nævnt før er der ikke noget overraskende eller usædvanligt i dette forhold.Set fra klassiﬁkationsdirektørens side er det let at forestille sig reaktionen, når detomhyggeligt opbyggede klassiﬁkationssystem, som han var ansvarlig for, pludseligblev udsat for presset fra sådan en ulykke med alle de deraf følgende pres på om-råder som udenrigspolitik og information til oﬀentligheden.Dokumentet kunne fortjene en mere indgående undersøgelse, men her må vi be-grænse os til sagens kerne, som var, hvor meget man kunne fortælle danskerne om det178

udspredte plutonium uden at give dem nøglen til hemmeligheden om, hvor megetplutonium der præcis var i våbnene. Den logiske kandidat til de maskerede ord i sidstelinje af klippet – efter ‘successfully conceal’ – er målinger af plutoniummængdernepå våben- og ﬂyskrot.14. marts 1968, dok. 909684Memorandum af W.B. McCool, Secretary of the AEC.Dette memorandum opsummerer de beslutninger, der blev taget på AEC’s møde 780den 11. marts. Forud var det blevet undersøgt, om man kunne overgive den relevanteoplysning om plutonium til danskerne igennem NATO, men denne løsning havdeikke vist sig mulig. Efter at have overvejet forskellige alternativer havde kommissionenfundet, hvad man vel kan betegne som et kompromis.‘Kommissionen besluttede, at (a) det faktum, at ca. [ord slettet] plutonium var ind-blandet i ulykken i Grønland, og (b) vores bedste skøn over, hvor meget plutoniumvi har fjernet fra ulykkesstedet, kunne gøres tilgængeligt uden skade for fælles forsvarog sikkerhed. Samtidig med denne beslutning om afklassiﬁcering besluttede kommis-sionen også, at disse data skulle overgives den danske regerings repræsentanter som‘privilegeret information’ med anmodning om, at deres udbredelse blev omhyggeligtkontrolleret, og at der skulle tages administrative forholdsregler til fornøden kontrolmed deres udbredelse inden for USA’.

I situationen så de danske myndigheder formentlig dette som et tilfredsstillende kom-promis, som på den ene side gav dem en forsikring om, at der ikke var mere plutonium,end de selv antog, og dermed et værktøj til kontrol med miljø og sundhed i området,og på den anden side tog vare på et af deres andre hensyn, som var at undgå unødigbekymring i befolkningen. Det sidste er naturligvis et vigtigt og legitimt aspekt afenhver ansvarlig krisestyring.Det var en lille politisk sejr for Carl Walske at få disse oplysninger afklassiﬁceret. Hanforstod selvfølgelig, at det ville være umuligt at få det nøjagtige indhold af plutoniumi våbnene afklassiﬁceret og stillede sig i stedet tilfreds med en afrundet værdi. Dette179

var i øvrigt tilstrækkeligt for hans formål, som var at give den danske regering enforsikring om, at der ikke var mere plutonium i våbnene, end den selv antog. CarlWalskes behandling af dette spørgsmål viser ham som både en smidig operatør ogen klarsynet statsmand.I dette dokument møder man igen et par eksotiske blomster i sikkerhedsembedsfol-kenes (security reviewers’) jungle. Vi er nødt til at se i et andet dokument i samlingen,dok. 138077 af 18. juni 1968, for at ﬁnde ud af, at de maskerede ord i klippet ovenforfra dok. 909684 er ‘6 kgs.’, selvom denne oplysning ﬁndes på DOE’s eget website ogindgår iFinal Responsefra 1995.I øvrigt er de korte, uformelle optegnelser fra det dansk-amerikanske møde i Wa-shington 18.-19. marts 1968 også meget diskrete i denne henseende og nævnerikke, om den nyligt afklassiﬁcerede information om ‘ca. 6 kg plutonium indblandeti ulykken’ rent faktisk blev givet til danskerne ved denne lejlighed (AEK 18-19/31968).Som nævnt er Marshalls memorandum af 8. marts (AEC 907/28), der var beslut-ningsgrundlag for AEC på mødet den 11. marts, tilbageholdt og ikke afklassiﬁcereti sin 107004-skikkelse, men afklassiﬁceret som 909684.Når det gælder informationsniveauet, skal man huske på, at der ikke er noget fuld-stændigt sammenfald mellem den virkelige verden og den bureaukratiske beslutnings-tagnings verden. I den virkelige verden var danske og amerikanske videnskabsmændsammen både i arbejde og hvile og under ekstreme og usædvanlige omstændigheder.I nogle tilfælde rejste de også på samme ﬂy med masser af tid til sokratiske dialogerom plutonium.I den virkelige verden var de danske videnskabsmænd bemærkelsesværdigt veloriente-rede om ‘Den Hellige Gral’, mængden af plutonium i hver pit. I begyndelsen af februarhavde Kofoed-Hansen, som vi har hørt, meddelt den danske atomenergikommission,at hvert våben antoges at rumme ca. 2 kg (Notits 5/2 1968).Den 21. marts noterede en anden dansk videnskabsmand, Asker Aarkrog, der vari Thule, i sin dagbog og rapporterede i et telegram, at ‘Jim Olsen [helsefysiker fraLivermore] siger, at der i alt var mindre end de 7-8 kg Pu i bomberne, man havdeantaget fra dansk side. Vel snarere omkring de 5-6 kg (mit indtryk fra samtalen)’(Aarkrogs dagbog).180

Det var ti dage efter at beslutningen var blevet truﬀet i Washington om, at danskernepå fortrolig basis skulle kunne informeres om, at der var ca. 6 kg plutonium indblandeti ulykken. Som vi har set, var Walske aktiv i bestræbelserne for, at danskerne kunne fådette tal at vide. Det kan noteres, at i henhold til telegramstrømmen mellem Washingtonog Thule var Walske og Jim Olsen i jævnlig kontakt med hinanden i denne periode.En rapport fra den amerikanske videnskabelige rådgivergruppe i Thule beretter omdens drøftelser med den danske videnskabelige gruppe. Rapporten bekræfter, at ‘detdanske skøn for den samlede mængde af aktivt materiale i våbnene var ca. 2 kg pr. våbeneller ca. 8 kg. Vi brugte deres tal i drøftelserne med dem’. Rapporten var klassiﬁceret‘Hemmelig’ og blev afklassiﬁceret i 1994. Den omtaler de danske videnskabsmændsom ‘en aktiv og kvaliﬁceret gruppe’ og ‘åbenlyst yderst dygtig’ (Crested Ice SAC 1969,Vol. IV, Annex i). Teknisk var gruppen veludstyret til jobbet (AEK 29/1 1968).I et andet amerikansk dokument bekræftes indtrykket af et hold af kompetente danskevidenskabsmænd. Dokument 318355, et memorandum af 7. februar til dr. Walske omdet radiologiske forureningsproblem i Thule, indeholdt en anbefaling af, at der skulleudarbejdes en model for våbnene i ﬂyet, fordelingen af våben- og ﬂyskrot, samt parti-kelstørrelse og fordeling af plutonium. Walske ﬁk oplyst, at Sandia havde udarbejdettilsvarende modeller tidligere, og memoet fortsatte: ‘Det danske hold har udarbejdeten sådan model, og deres amerikanske kolleger bør have et tilsvarende redskab’.En sammenligning med, hvad man (måske) troede i den svenske Försvarets Forskningsan-stalt, siger os, at de danske vurderinger ikke var noget, man lige havde taget ned fra hylden.Forskningsanstalten var ikke meget præcis i sit udkast af 14. februar 1968 til et svar fraden svenske statsminister til et rigsdagsmedlem angående forureningen i Thule. Det erimidlertid meget sandsynligt, at Försvarets Forskningsanstalt ikke ønskede at være præcisog med held forsøgte at give et svar, som man kan kalde for upræcisionens triumf.Svenskerne havde sendt deres udkast til den danske atomenergikommission for at høredens mening. Det svenske udkast opregnede uran 235, uran 238 og plutonium 239 ogfortsatte: ‘Den totala mängden av dessa ämnen överstiger med säkerhet ej något hundratalkg’. Det er et vidt begreb, men betyder noget i retning af ‘nogle få hundrede kg’.I deres svar på det svenske spørgsmål skrev H.H. Koch og Jørgen Koch, at plutoniumvar den relevante substans – hvilket svenskerne naturligvis vidste – og at mængdenheraf ‘formentlig [lå] i størrelsesordenen 10-20 kg’. H.H. Koch, der ganske sikkertikke havde glemt de 8 kg, som Kofoed-Hansen havde rapporteret, balancerede181

formentlig mellem to hensyn: ikke at lade overdrevne forestillinger om mængdenaf aktivt materiale sprede i den svenske oﬀentlighed og derfra videre ud i verden, ogikke at kompromittere en allierets fortrolige oplysninger (Notits 15/3 1968). Vi harikke undersøgt den svenske statsministers endelige svar.Man kan let forestille sig, hvordan den danske opfattelse udviklede sig. Danskerneﬁk åbenbart deres informationer ved en blanding af observation og konversation.Ikke ved direkte formidling af præcise tal eller deciderede sikkerhedslækager, men idiskussioner af den art, hvor antagelser luftes, og modforestillinger og kropssprog eren del af kommunikationen.Oplysninger, som erhverves på den måde, har to vigtige træk: De er nyttige for ensituationsbedømmelse, men er vanskelige at anvende på troværdig måde i formel,oﬀentlig kommunikation, fordi de ikke kan underbygges.14. marts 1968, dok. 106996Dette dokument rummer en brevveksling mellem dr. Walske og klassiﬁkationsdi-rektør Marshall. Walske har fået sin vilje og kan nu meddele danskerne den mængdeplutonium, som amerikanerne var ved at fjerne fra sne og is i Thule, samt et cirkatalfor, hvor mange kilo plutonium der indgik i ulykken.Gåden består her i, at Walske skriver ‘kilogram plutonium i alt i de ﬁre våben [halvlinje maskeret]’. Vi må forsøge at gætte os til, hvad han siger i den maskerede halvelinje. Måske noget i stil med ‘udtrykt som en tilnærmet mængde på 6 kg indblandeti ulykken’, eller noget om ‘en afrundet værdi’. Dette er et gæt – der er ﬂere andremuligheder.

Som nævnt før, tror vi imidlertid, at Walske var grundlæggende oprigtig og velme-nende i denne passage, hvor han taler om den samlede mængde plutonium i våbnene,selvom ordene bag den sorte bjælke sikkert vil vise, at tallet ville være en tilnærmelseeller en afrundet værdi, som Walske havde kaldt det ved en anden lejlighed. Samtidigmå vi indrømme, at det tog lang tid, før vi kom til det punkt, hvor vi troede på, atdette tal var nogenlunde rigtigt.I begyndelsen var vi temmelig skeptiske og tænkte, at formuleringen ‘involved in theaccident’ var en smidig bureaukratisk eufemisme, hvis formål var at skjule bombernesegentlige indhold. Gradvis er vi kommet til den nærmest modsatte opfattelse, at detfaktisk er en smidig bureaukratisk formulering, der gør det muligt at sige noget, der ernæsten rigtigt i en form, der var relevant for danskerne på dette tidspunkt – samtidigmed at man forsvarede det standpunkt, at plutoniumindholdet i konkrete våben varhemmeligt.Spørgsmålet om plutoniumindholdet i våbnene tages op igen i kapitel 5 og i appen-diks, hvor oplysningerne fra de tilgængelige kilder opsummeres.13. marts 1968, dok. 104813Femte statusrapport fra general Giller til formand Seaborg mﬂ., AEC. Vi er nu tæt på detdansk-amerikanske ekspertmøde i Washington, som fandt sted 18.-19. marts 1968.Det bemærkelsesværdige ved den femte statusrapport er igen maskeringen. Hundenhverken gør eller bider, men den knurrer lidt.

Forskellen er, at den sidste halvanden linje er maskeret i dok. 104813. Vi må spørge:‘positive identiﬁcation’ af hvad? Formentlig af en relevant våbendel, som alleredeer blevet fundet. Taler vi om den oralloykomponent, der blev fundet den 4. marts(dok. 107007)?Et andet bemærkelsesværdigt træk ved dette dokument er dets diskussion af ønske-ligheden af og måden for frembringelse af en materialebalance for plutonium, altsået plutoniumregnskab. Det blev vurderet ‘højst ønskeligt at frembringe en sådanmaterialebalance for at (a) imødekomme AEC’s interesse i de mængder, som manskulle håndtere, (b) imødekomme AEC’s interesse i helbreds- og sikkerhedsmæs-sige aspekter af den mængde, der ikke blev fjernet fra ulykkesstedet, og (c) forsikreden danske regering om, at den fornødne oprydning var gennemført’. Blandt deønskede aktiviteter var målinger på især tre typer aﬀald: det ﬂydende, ﬂyskrot ogvåbenskrot.Slutresultaterne af målinger i disse tre kategorier er endnu ikke blevet givet til dendanske regering. Man kan roligt sige, at forståelsen for den danske regerings interes-ser var mere udtalt i 1968 end for eksempel i 1988 og 1995. Hvis den amerikanskeregering valgte at sende disse oplysninger til den danske regering i morgen, ville detstadigvæk være ‘quick response’ i perspektivet af 24.000 år – ‘quick response’ er bedreend ‘ﬁnal response’. Heldigvis har DOE erklæret, at ‘ministeriet er interesseret i ideerfra oﬀentligheden til, hvordan det kan gøre oplysninger tilgængelige, der er af legitiminteresse for oﬀentligheden’ (DOE 1996; jf. Chu 2009).Dette emne blev også berørt i det følgende dokument.

15. marts 1968, dok. 104812Noter om Thuleplutonium, internt memorandum, Division of Operational Sa-fety.Den 13. marts anså man, at alt vigtigt våbenaﬀald var indsamlet og sendt til RockyFlats til videre besørgelse. Man anmodede om, at det nøjagtigst mulige skøn skulleudarbejdes over plutoniumindholdet i disse pakker. Vi kender ikke resultatet afdette skøn for plutoniumindholdet i våbenaﬀaldet. Man skulle tro, at det ville værehøjere end for ﬂyaﬀaldet, hvori der efter memoets udsagn ikke var fundet betyde-lige mængder. Måske var Langham ikke enig i det. Nogle få dage senere sagde hantil den danske delegation, at muligvis 5 pct. af plutoniummængden var hamretind i ﬂydelene. Det manglende kendskab til resultatet af målingerne på våben- ogﬂyskrot indvirker negativt på nutidens forsøg på etablere et plutoniumregnskabfor Thuleulykken.Walske havde som nævnt formentlig argumenteret med, at for at give danskernetallet på ca. 6 kg plutonium var det nødvendigt eﬀektivt at kunne skjule plutoni-ummængderne på våben- og ﬂyskrot. Det var nok mest af alt et taktisk argumenttil intern brug i den amerikanske administration. Her mere end 40 år senere, ognu da vi kender tallet på 7,5 kg for indholdet i våbnene, ville det forekomme lidtdogmatisk at fastholde en ﬁktion om, at der ikke blev foretaget målinger af disseværdier. Det ville i hvert fald ikke være i Walskes ånd.

19. marts 1968, dok. 106985Dette er den sjette statusrapport fra Giller til AEC’s formand. Desværre er bilageneifølge noten fra sikkerhedsgennemgangen ikke blevet tilgængeliggjort. Disse bilagville have givet et godt billede af undersøgelserne af våbendelene på Rocky Flats fremtil det øjeblik.Det ene af de manglende bilag er et memo fra Hancock til Giller af 13. marts, detandet er en rapport med titlen ‘Vurdering af våbenskrot fra Thule, med bilag’.Det ville uden tvivl have været nyttigt at have adgang til ‘Vurdering af våbenskrotfra Thule’, eftersom dette må formodes at være hovedvurderingen af de første 23sendinger af våbenkomponenter og våbenaffald fra Thule.I kapitel 5 kan man imidlertid se, at der faktisk findes et kort sammendrag afbjergede våbendele, omend det er en maskeret og langtfra komplet liste. Dettesammendrag findes ikke i 348-samlingen fra DOE’s arkiv, men i DOD’s læsesalpå nettet (Broken Arrow Thule 1968).Vi sigter især til den vigtige oplysning i dette dokument om, at en analyse fore-taget af AEC af bjergede komponenter fra secondaries viste en bjergningsrate på85 pct. for uran og 94 pct. af vægten af tre secondaries. Det ville ikke være over-raskende, hvis denne oplysning også kunne ﬁndes i de fristforlængede bilag, somlige er nævnt.Hvad der imidlertid er af yderste vigtighed i den sjette statusrapport fra generalGiller, er, at den opregner de bjergede dele fra den fjerde bombe, SN 78252. Bådeen tritiumbeholder og faldskærme er identificeret som hørende til SN 78252.De er i dårligere tilstand end de samme dele fra de andre bomber. Dette kunnemeget vel være tegn på, at SN 78252 som helhed var blevet endnu hårdere be-skadiget end de andre våben. Hvis det er tilfældet, er det ikke så overraskende,at det viste sig umuligt at finde andre identificerbare dele af denne bombe. Detfjerde tritiumreservoir var senest blevet fundet i dagene lige før den 2. februar,hvor det var blevet sendt til Los Alamos i den første sending af våbendele (dok.106883).Reservoiret er mere vigtigt for den officielle forklaring end faldskærmene. Al-lerede på grund af tabet af reservoiret var den fjerde bombe blevet inoperativ.Dette er en tungtvejende bekræftelse af den officielle forklaring på bombernesskæbne.186

Ved at udpege disse dele fra bombe SN 78252 som værende i en værre tilstand endtilsvarende dele fra de andre bomber indbyder man til spekulation om, at når ame-rikanerne overvejede en mulig bjergning af en meget veldeﬁneret våbenkomponent,tænkte de måske mere på en af de andre secondaries, hvoraf de havde fundet identi-ﬁcerbare dele, end på SN 78252, som de kan have antaget var fuldstændig splittet adog – hvis den overhovedet eksisterede mere – da måske kun som små uidentiﬁcerbarestykker, der lige så sandsynligt kunne være blevet samlet op på isoverﬂaden allerede,som de kunne ligge og vente på et undervandsfartøj på havbunden.Denne sandsynlighedsbetragtning kan muligvis støttes af en dristig konjektur, derville pege på, SN 453171 som en mere sandsynlig leverandør af en manglende vå-benkomponent. Vi bygger denne konjektur på en passage i dok. 107041 af 12. april.Et gæt ville være, at den første sorte bjælke skal udfyldes med for eksempel ordene‘oralloy’, ‘several’, eller med et tal. Den anden sorte bjælke skal måske erstattes medordet ‘primary’.

Ved fortolkningen af dette er det første, man skal huske, at uran 235 fandtes i primarypits i større mængde end plutonium. Der er endvidere stor sandsynlighed for, at i hvertfald dele af uran og plutonium i primary pits var integreret i et vist omfang, enteni produktionsprocessen eller mere sandsynligt i eksplosion og brand. Hvis sådannestykker var blevet fundet, ville det ikke have været vanskeligt at skelne dem fra stykkeraf rent uran 235 fra secondary pits. Især ikke, da det er rimeligt at antage, at oralloyi primaries var af højere renhedsgrad end oralloy i secondaries.Hvis dette ræsonnement er korrekt, øger det sandsynligheden for, at der ikke varfundet stykker fra primary pits. Dette er konsistent med det overordnede billede af,at alt ﬁssilt materiale i primaries var blevet spredt i partikelform ved eksplosionerne.Samtidig reducerer det muligheden af, at der skulle være nogen stykker af primarypits at tage i betragtning i den endelige beregning af, hvor meget plutonium der blevspredt. Men uden adgang til vurderingerne af de første 23 sendinger med bjergedevåbendele kan dette naturligvis kun være formodninger.Hvis vi fortsætter ad dette temmelig spekulative spor, gætter vi på, at alle bjergedestykker af oralloy/uran 235 kom fra secondaries. Fra det nævnte Air Force-dokument,der citerer en AEC-analyse ved vi, at betragtelige mængder af uran rent faktisk blevbjerget, helt præcis 85 pct. fra tre secondaries (Broken Arrow Thule 1968).Hele citatet lyder sådan: ‘En analyse foretaget af AEC af bjergede komponenter frasecondaries viser en bjergningsrate på 85 pct. for uran og 94 pct. opgjort efter vægtaf tre secondaries. Ingen dele af den fjerde secondary er blevet identiﬁceret’ (BrokenArrow Thule 1968).Lad os huske det, når vi kommer til analysen af den ‘manglende komponent’. Det børbemærkes, at vi ikke kan vide, om de 85 pct. henviser til alle slags uran i secondarieseller kun til uran 235.Den 30. marts 1968 markerede den oﬃcielle afslutning på vurderings- og bjerg-ningsdelen afCrested Ice.Denne dato giver en lidt bedre forståelse af situationenend Lee Hancocks bemærkning i dok. 106883, hvori han rapporterede, at efter-søgningen efter ﬂy- og bombedele på isoverﬂaden blev anset for afsluttet den 20.februar. Dette er ikke korrekt, eller skal i det mindste forstås sådan, at jagten nuhavde skiftet format og var blevet til en eftersøgning efter dele, der var begraveti isen. Mens Hancock skrev sin rapport, fortsatte jagten efter dele af oralloy påisen.188

18.-19. marts 1968, AEK 18-19/3 1968Dokumentet indeholder uformelle stikordsnotater fra de dansk-amerikanske møder iWashington. Ved denne lejlighed blev den såkaldte ‘gentlemanaftale’, som man nåedefrem til i København en måned tidligere, suppleret og endeligt indgået.Lad os nævne nogle få punkter fra de danske notater. For det første sagde Walske, atalle oplysninger om absolutte mængder var konﬁdentielle. Det siges ikke i notaterne,om mængden på ca. 6 kg blev nævnt. For det andet skønnede Langham, at måske5 pct. af plutonium var blevet hamret ind i ﬂydelene. Hvis man går ud fra 7,5 kgplutonium i våbnene, ville dette svare til ca. 0,4 kg.Walske nævnte, at amerikanerne gerne ville ‘eftersøge attraktive rester’. Dette kunnenaturligvis kun forstås som våbendele. H.H. Koch svarede, at de danske myndighederville undersøge området og diskutere resultatet med amerikanerne, hvis der blev fun-det noget (‘scanne areas og hvis der er noget taler vi med USA’). Lidt senere spurgteKoch, om der ville blive nogen undervandseftersøgning (‘Look at sea-bed?’). Walskeforeslog en formulering, som i den endelige aftale lyder: ‘11. Spørgsmålet om en muligundervandseftersøgning blev henvist til yderligere undersøgelse ved U.S. Air Force afomkostninger og nytte. Skulle en sådan eftersøgning blive foretaget, vil resultaterneblive gjort tilgængelige for den danske atomenergikommission’.H.H. Koch accepterede denne løsning, og Walske forklarede, at amerikanerne næppeville bjerge noget. Der var noget, luftvåbnet gerne ville vide, men man ville helst ikketrække afslutningen ud. (‘Vi henter næppe noget op. Airforce vil gerne vide noget,men vil nødigt trække afslutningen ud. Også cost consideration’).Walskes her citerede bemærkninger viser, at det allerede i midten af marts var kendt,at en interessant våbenkomponent manglede. Vi ser her nogle af de første tegn på, aten undervandseftersøgning kunne vise sig ønskelig. Stik imod, hvad BBC-journalistentror, ﬁk danskerne tidligt at vide, at amerikanerne måske ville ﬁnde det ønskeligt atlede efter ‘attraktive rester’.Kronologisk er vi midt i en kæde af begivenheder, hvor uran 235 eller oralloy spillerhovedrollen. Det begynder den 6. februar med en særlig indsats for at ﬁnde oral-loydele. Senere hovedbegivenheder er fund af nogle af oralloydelene i slutningenaf februar og begyndelsen af marts, punktet om en undervandseftersøgning i dendansk-amerikanske aftale af 19. marts, og derefter en rapport fra Sandia af 2. maj 1968(dok. 107032), hvori det manglende objekt beskrives. Yderligere begivenheder på189

tidslinjen er f.eks. et møde i København den 18. juli 1968 mellem general Glasser ogH.H. Koch med syv deltagere (se nedenfor) vedrørende en havbundsrekognoscering– og endelig dykningerne i Thule i august måned og debrieﬁng på Walskes kontor iPentagon af de deltagende oﬃcerer fra luftvåbnet i september 1968.19. april 1968, dok. 107038Memorandum fra H.D. Bruner, souschef for AEC’s sundhedsfaglige forskningsafde-ling. Emnet er mødet med den danske delegation, som vi lige har set på gennem dedanske noter. Det er et nyttigt, velskrevet memorandum på syv sider med bilag.En interessant side af dokumentet set fra et våbenbjergningssynspunkt er dr. Lang-hams formidable rekonstruktion af nedstyrtningen, og hvad der skete med bomberne,i det sekund ﬂyets næse ramte isen. I et interview mange år senere, i 1995, huskedeLanghams ægtefælle, Julie Langham Grilly, stadigvæk, hvor optaget han havde væretaf, hvad der skete i nedstyrtningsøjeblikket (Grilly 1995).Den i det følgende citerede del af Langhams rekonstruktion er af særlig interessefor den hypotese om en af bombernes muligvis særligt hårde skæbne, der bygger påden specielt voldsomme ødelæggelse af tritiumreservoir og faldskærme fra bombeSN 78252. Her er, hvad Bruner skrev ned om denne del af Langhams præsentation:‘Våbnenes højeksplosive sprængstof detonerede under hovedbrændstoftankene, ogderfor er mængden af jetbrændstof i centrum af det revnede område minimal. Våb-nenes meget store eksplosionskraft forklarer det netagtige mønster, som revner ogisblokke danner. Han postulerede, at et af våbnene var detoneret først, og at chokbøl-gen herfra ﬁk de tre andre til at gå af. Det forekommer sandsynligt, at eksplosionensplittede plutonium og legering ad (disintegrated the Pu and alloy), og omgivet, somde var, af brændstoftanke etc. burde dette metal have ramt og være blevet hamret indi overﬂaderne af den ene side af mange af metalvragstykkerne, men ikke alle; dettevar, hvad man fandt’.1. april 1968, dok. 107047Rapport om undersøgelse af våbenskrotsendingerne nr. 24 og 25 fra W. Lee Hancock,repræsentant for AEC ved LASL, Albuquerque, New Mexico, til general Giller iAEC’s hovedkvarter i Washington.Denne rapport og den følgende 107041 af 12. april er interessante derved, at de giveren idé om, hvad det ville have betydet, hvis hovedrapporten af denne art, den fra 13.marts, som dækker undersøgelsen af de første 23 sendinger, havde været tilgængelig.190

Der er en forbindelse mellem dokumenterne 107007 (6. marts), det herværende107047 (1. april), og det følgende 107041 (12. april).Genstandene i disse pakker blev sandsynligvis afsendt fra Thule efter den 6. marts(dok. 107007). ‘To pitstykker og et stykke af en secondary er blevet undersøgt påLos Alamos’. Den kendsgerning, at stykkerne var blevet sendt til Los Alamos først istedet for direkte til Rocky Flats er måske i sig selv af betydning. Det er antagelig ettegn på, at man mente, at stykkerne var af oralloy.Det første stykke, omtalt som ‘et stykke af en pit’, var 7,5 cm langt og 1,3 cm bredt.En anden genstand identiﬁceres også som ‘et stykke af en [ord slettet] pit’. Dissedele af pits blev videresendt fra Los Alamos til Rocky Flats med henblik på videreundersøgelse.‘Et stykke segment fra en secondary [ﬂere linjer slettet] er også blevet undersøgt.De vil også blive sendt til Rocky Flats til et prøvematch af secondarystykkerne medstykkerne af segment eller [ord slettet] fra secondary 28-1103 eller secondary 28-3573. Disse numre på secondaries er speciﬁkke for secondaries og adskiller sig frabombenumrene.Man kunne tænke sig, at disse to secondaries var mindre end intakte, måske i stum-per og stykker i modsætning til den tredje secondary, der var blevet bjerget næstenintakt. I dok. 106854 karakteriseres de to secondaries med disse ord: ‘andre stykkeraf secondaries nu i Rocky Flats’. Det kan være, at den ‘manglende våbenkomponent’hørte til en af disse secondaries.SN 690020 var den relativt intakte secondary, mens SN 453171 og SN 815950 havdeklaret sig dårligere. Som tidligere drøftet tror vi, at stykker af uran 235/oralloy frasecondary pits allerede var blevet matchet med bomberne SN 690020 og SN 815950,men ikke med SN 453171 og SN 78252. For så vidt angår SN 690020, støttes dennekonklusion af analysen af bjergningen af 20-punds-sektionen i dok. 106887 af 24.februar. Dengang konkluderede vi, at den bjergede ﬁssile kerne tilhørte bombe nr.1, SN 690020.Ræsonnementet er enkelt nok. Med hensyn til disse to våben, SN 453171 og SN815950, kan det have været muligt at se, eller i det mindste danne sig en idé om, hvadder manglede, og derefter give Sandia en komplet, meget nøjagtig beskrivelse af denmanglende våbenkomponent, sådan som det rent faktisk skete ﬁre dage senere, da191

En kandidat til den ‘manglende våbendel’ kan være skjult i den maskerede delaf nærværende dok. 107047. Med udgangspunkt i det ene stykke segment fraen secondary, der nævnes i begyndelsen af det maskerede afsnit, og den stand,det var i, kunne eksperterne måske udlede noget om en komponent, der havdeværet inden i segmentet, men som nu manglede. Vi arbejder med bind for øjneneher og kan naturligvis ikke være sikre på, at dette er tilfældet. Men måske kunnedette være et sted, hvor der nævnes noget, som henviser til vores tanke om denmanglende komponent, nemlig et stykke uran 235/oralloy fra det ﬁssile materialei en secondary.Måske drejer det sig ikke om et tilfælde, hvor alt oralloy fra en secondary mangler.Det kan også være, at der kun manglede et lille afbrækket stykke i et puslespil. Snartfår vi imidlertid at se, at amerikanerne i virkeligheden gættede på, at det var en intaktkomponent af oralloy, der manglede, men hvordan kunne de være sikre på det? Detkunne de naturligvis heller ikke. Nogle af de bjergede dele af oralloy var trods alt retsmå, og det samme kunne jo være tilfældet med den savnede del.Hvor stor var komponenten af uran 235/oralloy i en secondary? Måske omkring 8kg, hvilket i volumen svarer til mindre end en halv liter. Både uran og plutonium ertunge metaller, ca. 20 gange tungere end vand. På dette punkt i undersøgelsen kendervi ikke formen på genstanden og ved ikke, om den var delt op i ﬂere sektioner, ellerom den var så soﬁstikeret udformet, at dette i sig selv gjorde det særlig vigtigt at søgeefter den.På grundlag af de maskerede dele i et dokument fra Sandia nedenfor, dok. 107032,vil vi spekulere lidt videre over objektets fysiske karakteristika, og om eksperterneantog, at det var helt eller delt.Det bemærkelsesværdige er, at amerikanerne ledte efter noget, der måske ikke var størreend en halv liter. Antager man, at genstanden var hel, hvilket ikke nødvendigvis vartilfældet, ville det under alle omstændigheder være en lille genstand at identiﬁcerepå havbunden blandt tusindvis af stykker ﬂyskrot.5. april 1968, dok. 106854Niende statusrapport fra general Giller til AEC’s formand.Dette er Gillers opsummering af Hancocks rapport af 1. april, som vi lige haranalyseret. Giller refererer Hancocks rapport for, at to stykker var af interesse.193

12. april 1968, dok. 107041Rapport om undersøgelse af pakker med våbenskrot nr. 24, 25 og 26 fra W. LeeHancock, AEC’s repræsentant ved LASL, Albuquerque, New Mexico, til generalGiller i AEC’s hovedkvarter i Washington, D.C.Dette er det sidste dokument i den række af tre dokumenter, der er vores substitutfor en rapport af 13. marts, som dækker de første 23 pakker. Substitut i den forstand,at hvis man lægger dem sammen, så er de formentlig af samme type som rapportenaf 13. marts.De to korte maskeringer i slutningen af det efterfølgende lange klip giver en vel-kommen anledning til at diskutere et spørgsmål om terminologi. Problemet erenkelt; disse vigtige dokumenter vrimler med pitstykker og pitdele, der tydeligvishenviser til den ﬁssile kerne i secondaries, men vi har endnu ikke fundet en eksperteller et stykke litteratur, der vil eller kan bekræfte, at begrebet ‘pit’, der sædvanligvisanvendes om den ﬁssile kerne i primaries, også kunne bruges om den ﬁssile kerne,‘tændrøret’, i secondaries. En måde at skelne mellem de to slags pit på, kunne såeksempelvis være at tale om ‘primary pits’ over for ‘oralloy pits’, eller simpelthen‘secondary pits’.

Det er formentlig denne sprogbrug, vi ﬁnder bag de sorte bjælker ovenfor. Lad osanbringe de to afsnit ved siden af hinanden og udfylde de sorte områder, som vi tror,det skal gøres:1) ‘Vi har identiﬁceretoralloy-pitstykker[…]’2) ‘Ingen stykker er endnu blevet identiﬁceret som værende fraprimarypits’.Heraf følger, at de identiﬁcerede pitstykker ikke hører til primary pits. Hvis dennefortolkning er korrekt, var det almindeligt på dette tidspunkt at tale og skrive om‘pit’ ikke blot i primaries, men også i secondaries.5. april 1968, Walske-Koch 5/4 1968Brev fra Carl Walske, Oﬃce of the Secretary of Defense, til H.H. Koch.Blandt andet besvarede Walske et spørgsmål fra H.H. Koch om muligheden afen havbundsundersøgelse. Han underrettede Koch om, at han havde sagen underovervejelse sammen med general Glasser, ‘men mere som noget fotografering undernedslagsstedet end en egentlig eftersøgning. Beslutningen vil afhænge meget af, omder dukker noget enkelt op, både med hensyn til mandskab og udgifter. Eftersomaugust forekommer at være bedst egnet til sådan en undersøgelse, har vi stadig noget196

tid at løbe på, inden en afgørelse må træﬀes. I mellemtiden ser ﬂådens folk på sagenfor os. Jeg forventer at kunne give dig et svar inden for få uger’.To korte kommentarer må være nok. Den første er den temmelig åbenlyse,at vi ikke er vidner til forberedelserne af en stor, højt prioriteret undervands-operation, den anden, en bekendtgørelse om, at med eksempler af denne arthar vi så småt påbegyndt en kort proces, der modbeviser Coreras og BBC’spåstande om, at de danske myndigheder var blevet ført bag lyset med hensyntil undervandsoperationen. Ja, i virkeligheden startede vi denne proces alleredeen halv måned tidligere med Washingtonmødet 18.-19. marts og omtalen af‘attraktive rester’.Kilden ligger i dette tilfælde i Rigsarkivet i København, som Corera muligvis kender.Den er oven i købet på engelsk, så den ville ikke have voldt sproglige vanskeligheder,men Corera foretrækker dokumenter fra arkivet i Las Vegas.15. april 1968, Walske-Koch 15/4 1968Endnu et brev fra Walske til Koch, der havde inviteret Walske på besøg i København.‘Kaptajn McMullen og jeg ankommer den 28. maj kl. 9.45 og afrejser den 29. maj kl.14.00’. Denne lejlighed blev brugt til et møde i Atomenergikommissionen. Corerahar fået det hele galt i halsen, hvis han tror, at Walske havde tænkt sig at bruge toforårsdage i København til at føre Koch bag lyset.Walske fortsatte: ‘Jeg vedlægger supplerende data til dig og dine folk. De førsteotte bilag er de radiologiske målinger fra ﬂyvevåbnets ulykkesrapport […]. Bilag9 er en rapport fra Sandia Laboratoriets folk med deres beregninger af pluto-niumspredningen ved ulykken. Jeg forstår, at professorerne Rehberg, Bjerge ogKofoed-Hansen, samt hr. Busch, udtrykte interesse under mødet i Københavnfor at se dette’.De første otte bilag fra den rapport Crested Ice, som Air Force var ved at færdiggøre,var fem nærmere beskrevne appendikser fra Annex B og tre appendikser fra Annex I.De samme appendikser blev i 1988 sendt til den danske regering en gang til indpak-ket i en forsikring om, at dette var en ganske usædvanlig gunstbevisning. Undertidenhusker bureaukratierne dårligt.Den 2. maj sendte Walske igen et brev til Koch, bl.a. med en kort bemærkning om,at der endnu ikke var truﬀet beslutning om undervandsfotografering.197

22. april 1968, dok. 107036AEC’s sekretær fremsender med henblik på et møde i AEC general Gillers memo-randum af 18. april om en undervandseftersøgning ved Thule. Formålet med generalGillers memorandum er, ‘at give baggrund for en diskussion om ønskeligheden af atgennemføre en undervandseftersøgning efter manglende våbenskrot ved Thule’.I slutningen af april fremsendte Sandia Corporation sin lille studie af ulykken medhenblik på at udvikle parametre for en undervandseftersøgning af savnede våbendele.Hvor skulle man lede efter dem?Forsvarsministeriet (DOD) var interesseret i AEC’s indforståelse med hensyn tilønskeligheden af at gennemføre en undervandseftersøgning. Luftvåbnet havdevurderet forskellige metoder til udførelse af en sådan eftersøgning. I den maskeredepassage nedenfor før ordene ‘under-ice concept’ bliver genstanden for eftersøgningenformentlig identiﬁceret.Den undersøgelse under isen, som drøftes i dokumentet, skulle i givet fald have haftﬂåden som entreprenør, men den blev opgivet som værende uden for ﬂådens aktuellekapacitet og uigennemførlig inden for den tid, der var til rådighed, før isen brød op.Dette synes at pege på, at det var ﬂådens Curvsystem, man havde haft i tankerne.Curv havde også været anvendt i Palomares, og detaljerne passer med Curvs opera-tionsmønster.I stedet havde ﬂyvevåbnet ﬁnansieret en ﬂådevurdering af forskellige metoder tileftersøgningsoperationer, som kunne udføres, efter at isen var brudt op og bugtenklar til overﬂadeoperationer. I mellemtiden havde et hold oceanografer arbejdet vedulykkesstedet i Thule i et forsøg på at vurdere, hvor skrot kunne drive hen som følgeaf havstrømme. Det var planlagt, at denne gruppe skulle orientere Walske den 24.april.Flyvevåbnet regnede ikke med nogen særlig kompliceret eftersøgning, eftersom‘vandet er ret lavt (højst 200 m), og bugtens bund ligner en lille ørken. I betragtningaf at nedslagsstedet er kendt, og undersøgningsterrænet er glat, kunne brug af enslæbesonar og tv være en logisk søgemetode’.På dette punkt af overvejelserne ser det ud til, at kystvagten var parat til at støtte denlogistiske indsats, samt at der også kunne blive brug for et bemandet undervandsfartøjsom ﬂådens Perry Link deep diver.198

Som nævnt havde Sandia Corporation udført en studie, som kunne være nyttig vedudpegningen af søgeområdet.Forsvarsministeriet havde selv anstillet nogle overvejelser om ønskeligheden af enundervandseftersøgning. På den ene side kunne en eftersøgning føre til spørgsmålom, hvad der manglede, og det var klart, at selv en meget omfattende eftersøgningkunne mislykkes. På den anden side kunne selv en kort eftersøgning føre til fund afsensitivt, klassiﬁceret skrot, som en anden nation kunne bjerge, hvis amerikanerne ikkegjorde det. Forsvarsministeriet fandt, at det ville være en rimelig fremgangsmåde atlade undervandseftersøgningens omfang afhænge af resultatet af en kort eftersøgning.Her 41 år efter har sætningen ‘a search would lead to questions about what might bemissing’ vist sig at være ganske forudseende.De her citerede overvejelser afspejler ganske klart, at der ikke var tale om nogenbombe. Hvis det havde været tilfældet, ville argumenterne have lydt helt anderledes,og der ville ikke have været nogen diskussion af for og imod. Eftersøgningen villevære blevet gennemført med en massiv indsats, punktum. Det er åbenbart, at søg-199

ningen i Thule ikke på fjerneste måde blev anset for lige så vigtig som eftersøgningeni Palomares to år tidligere.Den af forsvarsministeriet foreslåede fremgangsmåde viser også, at man ikke var over-bevist om, at genstanden var der og kunne ﬁndes. Holdningen kan bedst beskrivessom ret afslappet. Den kan sammenfattes således: ‘Hvis genstanden ikke kan ﬁndesmed en ret begrænset indsats, så er der ikke noget at gøre ved det!’.De argumenter, vi har hørt ovenfor, skal man måske også kun i et vist omfang tagehelt alvorligt. De minder om et ikke helt ukendt adfærdsmønster i bureaukratiskesystemer, hvor institutioner og enkeltpersoner har en tendens til at dække ryggenmod den eventualitet, at en overordnet eller en konkurrent skulle dukke op og stilledet frygtede spørgsmål: ‘Vil det sige, at I overhovedet ikke har gjort noget?’. Hvis detskulle ske, er det godt at kunne sige: ‘Sir, vi har tænkt grundigt over sagen og enddaforsøgt, men desværre […]’.26. april 1968, dok. 909970Ved et kort informationsmøde før frokost havde AEC 33 forskellige emner på dags-ordenen – spændende fra det britiske syn på en gascentrifuge over godkendelse afrepræsentationskontoen (inden for hvis rammer staben skulle undersøge mulighedenfor en fælles reception for AEC og State Department) til rejseudgifter for modtagerenaf en Lawrence-belønningsmedalje. Thule var punkt 18 på den sprængfarlige dagsor-den. AEC godkendte en kort undervandseftersøgning efter våbenskrot. Dokumentetblev afklassiﬁceret i 1988.2. maj 1968, dok. 107032Dokumentet rummer resultatet af en undersøgelse fra Sandia Corporation, som havderegnet på, hvor på havbunden ‘et stykke våbenskrot’, en ‘savnet våbenkomponent’,eventuelt kunne være havnet. Der er ikke et ord om nogen bombe.

Vi lovede at vende tilbage til spørgsmålet om en nærmere beskrivelse af den savnedegenstand, og det prøver vi så på, selvom vi har bind for øjnene på grund af de maske-rede tal i afsnittene ovenfor.Første iagttagelse: Det er hverken en kugle eller en terning. Disse genstande har hverkenlængde eller ende. Anden iagttagelse: Vi kan udlede, at det er en cylinder med afrun-dede ender. Genstanden har længde og en sfærisk radius i begge ender, og tværsnitteter cirkulært, eftersom tværsnittet har en radius, der er den samme i begge ender.Hvad den hydrodynamiske del angår, gælder det, at en lav strømningsmodstandskoeﬃ-cient (drag coeﬃcient) giver gode hydrodynamiske egenskaber. Håndbøgerne oplyser, aten pingvin har en strømningsmodstandskoeﬃcient på 0,03, en glat kugle 0,1, en ru kugle0,4, en kegle 0,5, en lang cylinder 0,82, en terning 1,05 og en kort cylinder 1,15.Sandias strømningsmodstandskoeﬃcient for genstanden (med den sfæriskeende forrest) på 0,6 synes at passe meget godt til en lang cylinder med afrundedeender.201

Som vi tidligere har vist, blev der brugt mange kræfter på at bjerge dele af uran235/oralloy fra secondaries. Læseren kan måske også huske, at dr. Chambers i sitinterview med BBC talte om ‘det radioaktive materiale’. Referenceværdien forkernevåben af denne generation ligger på omkring 2 kg plutonium og 16 kg uran235. For at nå op på den tilstrækkelige mængde ﬁssilt materiale i primary gætter vipå, at de 2 kg plutonium har skullet suppleres med ca. 8 kg uran 235 (Albright etal. 1993. Tilstedeværelsen af U-235 i de konkrete primaries har været kendt siden denførste frigivelse af DOE-dokumenter i 1994. Dette er siden bekræftet i undersøgelseraf Eriksson 2002, 2008 og Nielsen & Roos 2006). Dette gæt giver 8 kg uran tiloverstil den ﬁssile kerne i secondary. En anden indikation er den sektion på 20 pund (9kg), som blev omtalt under 24. februar (dok. 106887).På den baggrund kan vi opstille nogle få konjekturer. Hvis cylinderen var en massivuranstav – den ﬁssile kerne i secondary, det såkaldte ‘tændrør’ – og hvis den vejede8 kg, og dens vægtfylde var 19,1 g/cm3, så ville cylinderens rumfang være 419 cm3,mindre end en halv liter. Det skal endnu en gang understreges, at vi ikke kender denfaktiske mængde uran 235, men kun har indikationer.Hvis man fordeler dette rumfang i en massiv cylinder med en diameter på 3,3 cm, ertværsnitsarealet 8,55 cm2og cylinderens længde ca. 50 centimeter. Det kan tilføjes,at uran er lidt blødere end stål. Det er smedbart, sejt og let paramagnetisk, menførst og fremmest forvitrer det let. Denne forvitring sker langsommere i koldt vandend i varmt; under alle omstændigheder indførte det endnu en usikkerhedsfaktor ieftersøgningen.Decimalerne er naturligvis uden betydning her. Argumentet handler alene om gen-standens karakter i grove træk, og det er derfor ligegyldigt, om diameteren er tre ellersyv eller et andet tal. Vi bør også holde døren åben for andre muligheder. For eksempelkunne de sfæriske ender være en del af et hylster omkring en kerne af uran. Hvis dettehylster var en del af den savnede cylinder, kunne dimensionerne være lidt større.Hvorfor skulle en uranstav have runde ender? Kunne det tænkes at have nogetat gøre med, at staven var hul, med andre ord et rør, og at de runde ender var enbekvem eller solid måde at lukke røret på? Eller var der andre årsager til denneforsegling af røret? Var det for at sikre, at strålingstrykket kun kunne påvirke røretudefra? En metallurg, kemiker eller fysiker kan måske besvare dette spørgsmål.Det nævnes ofte i litteraturen, at tændrøret kunne være hult, og det er da også detmest sandsynlige.202

I dok. 107047, som omtaler pitstykker, der med stor sikkerhed kommer fra se-condaries, diskuteres stykkernes vægtykkelse ﬂere gange. Det tyder ligeledes på, aturanstaven var et rør. Det vil ikke komme som nogen overraskelse, hvis uran-/oral-loyrøret betegnes som ‘secondary pit’ eller ‘oralloy pit’ i dokumenternes maskerededele, selvom vi ikke har kunnet få det bekræftet i litteraturen eller interviews.Hvis man især interesserer sig for tændrørets ydre dimensioner og dermed chancernefor at få øje på det, kan man sige, at røret ville være lidt tykkere og mere synligt end enmassiv stav. Hvis vi bruger de samme værdier som ovenfor, men regner med en ydrediameter på 5,4 cm og en indre diameter på 4,3 centimeter, ville rørets længde være50 cm med en vægtykkelse på 1,1 cm. Dette er som nævnt konjektur.Det ville under ingen omstændigheder have været nemt at ﬁnde en så lille gen-stand på havbunden. Endvidere skal vi huske, at selvom amerikanerne ledte efteren hel genstand – det viser beskrivelsen af et objekt med to sfæriske ender – var deogså nødt til at regne med muligheden af, at man kun kunne ﬁnde en del af gen-standen, eller at den måske var blevet slået helt i stykker. Sådanne stykker kunnevære blevet overset på isen og sneen på overﬂaden, eller rent faktisk allerede væreblevet opsamlet helt eller delvis i uidentiﬁcerbar stand, eller være spredt mellemtusindvis af små vragstumper på havbunden. En lille genstand, ja, men større endtændrøret i en bil, derfor har vi valgt at kalde den marskalstaven – den beskrivelsepasser bedre til størrelsen.Hvis genstanden virkelig havde ligget på havbunden engang, var der kun ringechancer for, at en så lille ting ville have været til at skelne i de sideskanninger, somDanmarks og Grønlands Geologiske Undersøgelse udførte i Bylot Sund i 2003. Detbehøver vi dog i øvrigt ikke at tænke nærmere over, idet genstanden for længst villevære forvitret (GEUS 2003).Sedimenteringsraten på havbunden er 2-4 mm om året, dvs. 8-16 cm i de 40 år, derer gået siden ulykken. Det nye sediment er gennem biologisk aktivitet blevet blandetgrundigt op med det gamle lag (Dahlgaard et al. 2001).I henhold til skitserne nedenfor regnede Sandia Corporation med, at genstandenmåske kunne ﬁndes på havbunden i et område mellem 15 og 45 meter fra nedslags-stedet. Beregningen byggede på forskellige forudsætninger om bl.a. genstandensudgangshastighed, nedslagsvinklen, vandets saltholdighed og stillingen i vandet påvej mod bunden.203

Som man måske husker, talte dok. 107036 om muligheden af, at et fremmed landkunne bjerge genstanden, hvis amerikanerne ikke gjorde det selv. Det er svært attro, at denne bekymring skulle have ligget højt oppe på skalaen, og den rolige tone idokumenterne taler imod det.Først og fremmest var genstanden nok af mindre betydning i en topbeslutningstagersøjne, og dernæst var der sikkert kun ringe udsigt til, at sovjetiske ubåde skulle snuserundt lige der og rent faktisk ﬁnde den.Efter at have bestemt den savnede genstands sandsynlige identitet, kan vi nu gå videretil dokumenter om eftersøgningen. Men først en supplerende oplysning om det ﬁssilemateriale i primary pits.28. maj 1968, dok. 107016Telex fra James [ Jim] L. Olsen, Livermore.Olsen giver meddelelse om inspektioner af ﬁssilt materiale på ﬂydele i CrestedIce-beholdere på Thule. ‘Alle fulde tønder blev undersøgt udvendigt med etSPA-3-instrument indstillet på 185 keV. Det ﬁssile materiale antages at værejævnt fordelt i tønderne’. Det bemærkes endvidere, at ‘eftersom plutoniummeter ﬁndelt, gælder det samme formentlig for uran 235’. Det må formodes, at ikkeblot plutonium, men også uran 235 i dette tilfælde stammer fra eksplosionerneaf primaries.

Den sammensatte pit havde ﬂere fordele i forhold til separat brug af materialerne:Et enhedsdesign kunne anvendes ved samtidig brug af begge til rådighed værendevåbenmaterialer. Brugen af uran 235 sammen med plutonium reducerede mængdenaf plutonium og således neutronbaggrunden, samtidig med at der krævedes en mindrekritisk masse, end hvis der kun blev anvendt uran 235.Det er nu over 20 år siden, dette dokument blev afklassiﬁceret med maskeringer. Tidener måske inde til en ny sikkerhedsgennemgang af de maskerede dele af dette dokumenttillige med slutrapporten om mængden af ﬁssilt materiale på alle bjergede ﬂydele.28. maj 1968, AEK 28/5 1968Ifølge det danske referat fra et møde i Atomenergikommissionen med H.H. Kochog Carl Walske som topforhandlere og ti yderligere deltagere var hovedemnet som-merens miljøprogram, dvs. monitering og afsluttende oprydning.Vedrørende ‘undervandssagen’ sagde Walske, at der formentlig ville blive truﬀetbeslutning i den kommende uge. Der var bl.a. et økonomisk problem, og måske varden ikke nødvendig. (‘underwater-research business / afgøres form. i næste uge / (bl.a. et økonomisk problem 200.000 $) / er form. ikke nødvendigt). En af deltagerne,kontorchef H. Lassen fra Ministeriet for Grønland, der prøvede at være hjælpsom,foreslog, at man kunne foretage en havbundsfotografering inden for rammerne afdet danske sommerprogram.

Walske svarede, at det ville man alvorligt overveje, mens H.H. Koch bemærkede, at‘man ikke [skulle] overdrive det med bunden. Jo mere man gør, jo mere vil folk trovi er i tvivl. [ Jeg] tror det er bedst at følge Lassens forslag (dvs. lade tage billeder påbunden samtidig med sommerprogrammet) og så ikke mere’. Walske svarede hertil,at man ville ‘tale om det i USA’.6. juni 1968, dok. 107114Brev fra AEC’s formand Glenn Seaborg til Carl Walske, Department of Defense,vedrørende undervandseftersøgning. Seaborg anbefaler, at det bombeaﬀald, manmåtte ﬁnde, bliver bjerget samme sommer. De maskerede linjer skjuler formentligen henvisning til en savnet våbenkomponent, som kunne beﬁnde sig på havbunden.Hvis Seaborg tænkte på marskalstaven, var det en fornuftig anvisning at skynde sig,da uran 235 forvitrer.

Det ville ikke have været let at følge formandens anvisning, hvis man havde fundetstore stykker vraggods. Undervandsfartøjet havde ikke kapacitet til større bjergnings-operationer. Det var udrustet med en mekanisk arm med en klo for enden. Kloenlignede nærmest en rørtang og kunne tage fat i stykker på måske op til 20 kg.2. juli 1968, dok. 107107Meddelelse fra James L. Olsen, Livermore, Californien, til bl.a. Ray Stone i DMA,AEC i Washington, Wright Langham, Los Alamos, oberst Montoya ved SAC’s hoved-kvarter på Oﬀuttbasen i Nebraska. James Olsen beder Ray Stone om at videresendemeddelelsen til en oberstløjtnant, der arbejdede med projekt Crested Ice i Thule.I meddelelsen anbefales forskellige metoder til dataindsamling vedrørende metalgen-stande, som kunne vise sig at være stykker af uran 235. Igen hører vi om SPA-3-instru-mentet, der kunne sænkes ned fra en helikopter for at identiﬁcere metalstykkerne.207

Instrumentet kunne indstilles til ‘upper level ratio of 3.3’ og en ‘peak response at 185keV’, som vi nu husker er signaturen for uran 235. To gange nævner rapporten uran 238.Det ved vi ikke rigtig, hvad vi skal stille op med. Det er næppe en fejlskrivning for 235,men måske et forsøg på at sløre det virkelige formål for modtagere i det yderste led.Dokumentet anbefaler også to andre metoder til dataindsamling. Dels at gennemføreen omhyggelig, fortløbende fotografering af området med den ituslåede is, indtil isensmeltede, dels at optage infrarøde billeder af det samme område. Alle disse bestræbel-ser afspejler en løbende indsats for at indsamle radioaktive stykker af våbnene. Jagtenpå marskalstaven var stadig i gang, nu fra båd og helikopter. Radioaktive genstandesvarmesignatur afhænger af materialets halveringstid. Varmesignalet fra plutonium ersåledes 30.000 gange stærkere end fra uran. Chancen for at ﬁnde marskalstaven eller deleaf den i grødisen ved hjælp af infrarøde billeder må således antages at have været lille.18. juli 1968, Notits 18/7 1968Dokumentet er Udenrigsministeriets korte resumé af et møde, som fandt sted iAtomenergikommissionen. Deltagerne var formanden for forretningsudvalget, H.H.Koch, generalmajor Glasser fra det amerikanske ﬂyvevåben, Gjørup fra Risø, toembedsmænd fra den amerikanske ambassade, og to embedsmænd fra kommissionenog Udenrigsministeriet. Desuden foreligger AEK’s egne håndskrevne mødenoter, deromtales under næste punkt.På mødet ‘fremkom generalmajor Glasser med en kort redegørelse for det amerikan-ske oprydningsprogram […]. Redegørelsen indeholdt følgende nye oplysninger: Fraamerikansk side vil man i begyndelsen af august d.å. aﬀotografere havbunden i etcirkelformet område omkring det punkt, hvor ﬂyet ramte isen. Områdets radius vilvære ca. 100 meter. Fotograﬁerne vil blive optaget ved hjælp af en slags mobil dyk-kerklokke (submersible), der er elektrisk fremdrevet, har 2 mands besætning, og somi én uge dagligt vil foretage ture til området fra havnen ved Thulebasen. […]. Der varenighed mellem Atomenergikommissionen og generalmajor Glasser om, at de alleredeforetagne oprydningsforanstaltninger og undersøgelser gjorde det yderst usandsynligt,at fotograﬁerne af havbunden ville frembyde indicier for, at der dér befandt sig resteraf ﬂyet eller fragmenter af de brintbomber, det medførte. Var dette tilfældet, ville detanvendte fartøj ikke være i stand til at foretage bjærgningsarbejde’.Tæt på, kan man sige, men ikke helt i plet. Som vi lige har hørt, havde Star IIIfaktisk en meget begrænset bjergningskapacitet, men kun for genstande på op tilmåske 20 kg, sådan som det var tilfældet for Star II. Denne kendsgerning var på208

den anden side ikke nogen stor hemmelighed. Den var almindeligt kendt på basen,og den fælles dansk-amerikanske publikation Crested Ice har et udmærket billede,der viser Star III i Thule med kloen fremme klart og tydeligt under næsepartiet.Der var også glimrende billeder af kloen i arbejde under vandet i den samling, somWalske efterfølgende sendte Koch.Det ville vist være overilet og unødvendigt at gisne om eventuel tvivl og detaljer om-kring denne erklærede enighed. Lad os i stedet konstatere den enkle kendsgerning,at i sommeren 1968 diskuterede danske og amerikanske embedsmænd mulighedenaf ﬂy- og våbenskrot på havbunden. Dette var et led i en fortløbende diskussion,der var påbegyndt ﬂere måneder tidligere i Washington, og muligheden af en sådanundersøgelse var blevet nedfældet i ‘gentlemanaftalen’.Hvorvidt danskerne eventuelt uformelt har fået at vide, at undervandsfartøjet villelede efter lige præcis et lille uranrør, var vist egentlig ikke af nogen større betydningi situationen, og næppe et operativt problem, der kunne gøre krav på en plads iforgrunden, især ikke når man tager usikkerhedsmomenterne i betragtning. Detville have været en helt anden sag, hvis amerikanerne havde haft viden om, at der låplutoniumkomponenter på havbunden, for ikke at tale om en hel bombe. Hvis derer blevet givet en sådan uformel orientering, hvilket vi ikke har kendskab til og i øv-rigt ﬁnder usandsynligt, ville det formentlig snarest have virket som en beroligendebekræftelse på, at der ikke var nogen bombe tilbage.18. juli 1968, AEK 18/7 1968AEK’s håndskrevne mødeoptegnelser synes at understøtte denne opfattelse. H.H. Kochskommentar til Glassers redegørelse var, at han var ‘glad for denne ﬁnal round up […]talte om det i Washington, vi ville ikke presse på med noget vedr. bunden men hvis I vilgøre det er vi glade for det. [Det betyder, at] no stone left unturned. [ Jeg er] glad for, atUS scientists [er] med i sommerprogramm[et]’. Koch sagde videre, at det var et megetnyttigt skridt at tage for ‘at være helt sikker på, at der ikke er noget vigtigt tilbage’. Oglidt senere, at man var ‘taknemmelige for den ekstra indsats’ (AEK 18/7 1968).Koch havde mere end rigeligt med oplysninger til at forstå, at undervandsundersø-gelsen ikke var nogen større operation. I realiteten var det dobbelte signal fra denamerikanske beslutning beroligende. Undersøgelsens beskedne omfang tillod hamat konkludere, at der ikke var nogen stor, styg ulv under overﬂaden, og samtidig gavundersøgelsen en ekstra garanti for, at så meget potentielt skadeligt vraggods sommuligt var blevet fjernet.209

Kontekst, hr. Corera! Brug af kilder fra begge sider, når man analyserer forholdetmellem to lande, hr. Corera! Og, hr. Corera, hvor besværligt det end kan synes, endoganvendelse af kilder på besynderlige sprog fra lande, der ikke har den uudsigelige lykkeat indgå i det angelsaksiske medieunivers.Hovedmotivet i den danske sagsbehandling var at få fjernet så mange af ulyk-kens konsekvenser som muligt. Dette hovedhensyn var ledsaget af afbalanceredebestræbelser på krisestyring, således at de nødvendige sikkerhedsforanstaltningerkunne gennemføres, uden at det gav anledning til unødig bekymring i befolkningen.Endelig respekterede danskerne den amerikanske sides hemmeligholdelseshen-syn, så længe det ikke blev anset for at kompromittere det danske hovedhensynafgørende.Det er ikke ukendt, at der opstår krydspres og paradokser i kriser, når der skal tageshensyn til befolkningens ve og vel, krisestyring, hemmeligholdelse, udenrigsforbin-delser og kommunikation med omverdenen. Disse vanskeligheder kan sommetiderovervindes med instrumenter fra det diplomatiske arsenal, for eksempel ved at plejetilliden og de gode forbindelser mellem de vigtigste aktører. Det forstod H.H. Kochog Carl Walske til fulde. Dette er almindelig diplomatisk snusfornuft, men kræverpersonlighed, hvis det skal virke. Disse ganske jævne betragtninger kan let beskrivesi en kort avisartikel, men de egner sig unægtelig ikke til stand-up-bravader på arktiskelokaliteter.

Coreras eventyr bør ikke afspore interessen for det, der er relevant i dag – den fortsattemonitering af ulykkens følger. Med lige dele professionalisme og sund sans formåedeKoch og Walske at ﬁnde gensidigt acceptable løsninger i en vanskelig situation, hvordet dansk-amerikanske forhold var under pres for at afbøde virkningerne af ulykkeni Thule og for at ﬁnde en varig diplomatisk løsning på ophøret af amerikanske ﬂyv-ninger med atomvåben over Grønland. Hvis man tænker i stokastiske baner, er detvanskeligt at forestille sig, at den samme professionelle behandling af sager vedrørendeulykken skulle kunne opretholdes i over 40 år uden lejlighedsvise afvigelser fra denfornemme standard, som Koch og Walske havde sat.27. juli 1968, dok. 107095Telex fra Chief of Staﬀ of the Air Force (CSAF), at undervandsoperationen nu ergodkendt og kan påbegyndes. Dokumentet blev afklassiﬁceret for 18 siden, i 1991.Hovedindholdet er en befaling for operationen. Det kan næppe overraske nogen, atdet betragtes som konﬁdentielt, at operationen omfatter eftersøgning af en genstandeller en våbendel. Det var der mange gode grunde til. Det samme blev sagt i dok.107113. Med henvisning til undervandsoperationens lange diplomatiske forbere-delse kan vi stilfærdigt sige til BBC’s journalist, at hans sensationsprægede påstandom, at danskerne ikke var underrettet om dykningernes formål, er lige så fjernt fravirkeligheden, som Oxford er fra Thule.Det er svært at forstå, at en dreven iagttager som Corera, der har en omfattende be-skæftigelse med britisk og amerikansk efterretningsvæsen bag sig, bygger så misvisendepåstande på et eller to dokumenter fra det amerikanske luftvåben og undlader at tagehensyn til den hierarkiske og opdelte karakter af konﬁdentialitet og hemmeligholdelsei staternes indbyrdes forbindelser. Til gengæld er det ikke svært at forstå, at man ikkekan vurdere det dansk-amerikanske forhold alene på grundlag af et par dokumenter,der er genereret uden for forhandlingernes hovedstrøm.Det er lidt forbløﬀende, at en journalist med en så oplagt interesse for arkivforskning,at han har rekvireret 348 dokumenter fra DOE’s arkiv i Las Vegas og har sovet med demunder hovedpuden i syv år, ikke har været i stand til at ﬁnde Rigsarkivet på kortet.24. august 1968, dok. 107074Og nu tilbage til Thule, hvor dykningerne var begyndt i august. Der blev gennemført11 dykninger med en produktiv undersøgelsestid på tre timer pr. dykning (CrestedIce 1970: 95). Dokument 107059 har en anden vurdering og anfører, at det kun var211

halvanden time pr. dykning. På den danske regerings anmodning udleverede amerika-nerne i april og maj 1988 16 timers videooptagelser fra dykningerne (HIAS 1988).Dokumentet er en daglig situationsmelding om Star III’s syvende dykning. Alle 11situationsmeldinger var lavt klassiﬁcerede ‘For oﬃcial use only’, men som det fremgåraf dok. 107072, der analyseres nedenfor, var der også meldinger, som var klassiﬁceret‘Secret’. Man kan ikke forvente at ﬁnde vigtige oplysninger om observerede våbendelei de daglige situationsmeldinger, der var klassiﬁceret ‘For oﬃcial use only’.Et ‘cirkelformet område omkring udgangspunktet med en radius på 180 fod blevinspiceret. […] Der ligger skrot imod nord fra lige syd for udgangspunktet og ud til180-fods-cirkelslaget. Der er en ret tæt koncentration ud til 120 fod, og så ser det udtil at aftage fra 120 fod ud til 180 fods cirkelslag. Under denne dykning observeredevi to forskellige røde stofposer. Vi vil forsøge at bjerge disse stofposer på dykning 8her til morgen ved at bruge manipulatoren, som er blevet repareret’.Manipulatoren var fartøjets mekaniske arm, der kunne udstyres med forskellige red-skaber, i dette tilfælde en klo. De, der har set billederne og videoerne, kan bekræfte, atkloen fungerede (HIAS 1988). Et øjeblik strejfer det en, at der måske ikke var nogetat komme efter, når man havde tid til at bekymre sig om et par røde stofposer.

Intet af dette svære og middelsvære ﬂyskrot blev bemærket under den omfattendeside scan sonar-undersøgelse, som Danmarks og Grønlands Geologiske Undersøgelsegennemførte i 2003 (GEUS 2003).27. august 1968, dok. 107072Dette er den supplerende situationsrapport, der oprindelig var klassiﬁceret ‘Secret’og kun til begrænset fordeling (limdis).Vi hører, at to oﬃcerer, ﬂyveroﬃcerer fra Directorate of Nuclear Safety, der deltog idykningerne, ‘har identiﬁceret stykker af yderbeklædning og beklædning af den balli-stiske sektion [nogle få ord maskeret] under dykningerne 8 og 9, den 24. og 25. august.En ydre, ﬂad kabelkanal uden stik [stor maskering, der dækker resten af afsnittet]’.214

‘De fotos og den video, der den 22. august 1968 blev vist til dr. Vibe og hans med-arbejdere, var blevet omhyggeligt gennemset før mødet og indeholdt kun ﬂyskrot.Ingen stykker som dem, der beskrives i denne melding, var blevet observeret ellerfotograferet på det tidspunkt. [maskering] (noforn)’. Det er rimeligt at forstå densidste formulering sådan, at der ikke under dykningerne før den 22. august var blevetobserveret våbendele. De vrimlede ikke ligefrem op af havbunden.Der er ikke noget bemærkelsesværdigt ved det ‘noforn’ i sidste linje, der betyder, atoplysningerne ikke må videregives til udlændinge. Som nævnt tidligere havde ameri-215

kanerne et lukket kredsløb til klassiﬁcerede oplysninger. Det var i overensstemmelsemed dette almindelige princip, at Vibe ikke måtte se billeder af våbenskrot.I øvrigt ﬁndes der en stor billedsamling fra dykningerne på Atomenergikommis-sionens akter i Rigsarkivet, og som nævnt ﬁk de danske myndigheder overdraget 16timers videooptagelser fra dykningerne i 1988 (HIAS 1988).Denne sag er en påmindelse om, at når det drejer sig om klassiﬁcerede oplysninger,får man næppe det fulde billede at se ved kun at læse lavt klassiﬁcerede dokumenter.Det er ikke overraskende, at man får to helt forskellige historier om dykningerne idisse få dokumenter. Desuden er der altid muligheden af, at der er dokumenter, somman slet ikke har adgang til eller kendskab til. Det er svært at vide, hvornår man hardet fulde billede. I dette tilfælde er der måske en dobbeltlås, først de maskerede deleovenfor og dernæst en særlig rapport om det fund, der omtales i den maskerede del.En sådan rapport kan have dannet grundlag for den orientering, som observatørerneefterfølgende gav på Walskes kontor. Vi venter spændt på at se indholdet.Vi vil nu lade som om, dette er de eneste oplysninger, vi har om dette fund. Det gørvi kun for at illustrere de frugtesløse spekulationer, som maskeringerne sommetiderkan forlede historikerne til. Heldigvis får vi efter disse, som det viser sig, undertidenfejlslagne overvejelser, en i det mindste delvis løsning i det følgende dok. 107059,eller snarere i den vedhæftede skitse.Den nævnte ‘external case section’ er måske et stykke af yderbeklædningen til enbombe, mens ‘ballistic case section’ kan være en del af hylsteret til våbnets forseglededel, der indeholder ﬁssionsudløseren i primary og den termonukleare del i secondary.Hvis det er tilfældet, må man spørge, om sidstnævnte beklædningsstykke slet ikkerummede dele af det oprindelige indhold, eller om der lå noget af det i nærheden.Bemærkningen om en ekstern kabelskinne uden kontakter giver det indtryk, at dekomponenter, som skinnen oprindelig var forbundet med, også kunne være bevaret.Omfanget af det maskerede stykke må få en til at tro, at der har været en del at sigeom dette fund, og om det kom som en overraskelse.Det fører til næste spørgsmål. Når man tænker på al den opmærksomhed, der var medhensyn til at identiﬁcere og matche våbenskrot på isen med speciﬁkke våben, var detså virkelig uinteressant at samle disse stykker op og forsøge at matche dem med etspeciﬁkt våben? Kunne de ikke have matchet nogle allerede bjergede dele, der blot216

endnu ikke havde kunnet henføres til et speciﬁkt våben? Kunne man besvare dissespørgsmål ved blot at se på dem under vandet og tage billeder af dem? Eller var fundeti sig selv, og de oplysninger, der ﬁndes i det maskerede afsnit, af en sådan karakter,at de udgjorde en af de sidste brikker i puslespillet? Måske et stykke i puslespillet,som fjernede nogle sidste, relativt hypotetiske bekymringer om, at der kunne liggeklassiﬁcerede genstande af en vis operativ betydning på havbunden?Vi kender ikke svaret, men bemærker den måske overraskende lethed, hvormed mantog beslutningen om at indstille Star III’s dykninger. Dykkersæsonen varede næsten enmåned endnu, så hvis der havde været vital interesse i at forlænge operationen, ville bu-reaukratiske vanskeligheder eller uﬂeksibel planlægning næppe have forhindret det.Her slutter eksperimentet, hvor vi har foregivet ikke at kende fortsættelsen.Det er ret oplagt, at undervandsoperationen i Thule havde langt lavere prioritet endoperationen i Palomares. Hvis vi sammenligner Thuleoperationens beskedne størrelse ogbeslutningen om at indstille den med den helt ekstraordinære og med held kronede indsatsfor at bjerge den savnede bombe i Palomares, forstår man, at der var en verden til forskel.Dette er mere end rigeligt til at fortælle os, at amerikanerne ikke ledte efter en bombe.Mere speciﬁkt er allerede den kendsgerning, at amerikanerne valgte Star III meddens yderst begrænsede bjergningskapacitet, et andet særdeles afslørende tegn på,at amerikanerne ikke ledte efter noget så tungt som en bombe, og heller ikke efterfysikpakken (primary og secondary samlet) eller en secondary.10. september 1968, dok. 107059Dette er fremsendelsesbrevet til tiende statusrapport fra general Giller til AEC’sledelse. Gillers rapport er dateret 6. september. Det er det sidste og vigtigste af dedokumenter, der omhandler eftersøgningen af våbenkomponenter på havbunden.Ved udstedelsen var det klassiﬁceret ‘Secret’ og handler om de samme begivenhedersom dok. 107072 af 27. august, men det har en del supplerende oplysninger. Mangeaf de spørgsmål, som dok. 107072 gav anledning til i vores analytiske eksperimentfor et øjeblik siden, besvares her i Gillers rapport.Når det er sagt, fortæller denne statusrapport os næppe alt om de tre ﬂyveroﬃcerersorientering på Walskes kontor i Pentagon. Hvis vi skal se det udførlige referat af brie-ﬁngen hos Walske og slutrapporten om dykningerne fra Directorate of Nuclear Safetyog stabschefen for ﬂyvevåbnet, må vi nok væbne os med tålmodighed lidt endnu.217

Først en bemærkning om beslutningsprocessen, som beskrives i første del af Gillersrapport. Efter iagttagelsen af små våbenstykker den 24. og 25. august havde CSAFgivet tilladelse til at forlænge eftersøgningen til den 28. august, men den planlagtedykning på denne dato måtte opgives på grund af dårligt vejr.Det ser vi som et tegn på, at der ikke var noget særlig stort engagement i at ﬁnde gen-standen – at det med andre ord ikke blev anset for at være af vital betydning at ﬁndemarskalstaven. Stabschefens tilladelse til at forlænge operationen med en enkelt daglyder mere som et ‘så tag da for Guds skyld et kig til!’. Denne resignerede indstillinggenfandt man hurtigt blandt beslutningstagerne i Washington.‘Commissioner Tape [from AEC] var enig i ikke at standse den foreslåede fremgangs-måde, efter at han af dr. Walske var blevet orienteret om, at dårligt vejr forhindrede endykning, og at alt var ved at blive pakket sammen til hjemturen. Walske talte også medgeneralmajor Glasser fra Headquarters USAF. Alle var enige om, at undersøgelsernekunne indstilles. Med indforståelse fra ministeren for ﬂyvevåbnet ﬁk chefen i Thuleordre til at standse operationerne […]’.Hele atmosfæren omkring beslutningerne bekræfter, at undervandsundersøgelsen iThule ikke var nogen højt prioriteret opgave og slet ikke i samme liga som operatio-nen i Palomares.Dr. Chambers’ omhyggeligt valgte ord, at ‘der var skuﬀelse over, hvad man kunnekalde de mislykkede bestræbelser på at få alle komponenter med hjem’, afspejler meget218

Hvad våbendelene angår, står der, at de var små og ikke hørte til en secondary. På denvedhæftede skitse kan man læse en mere præcis beskrivelse af genstandene. Den ‘externalcase section’, vi har hørt om i det foregående dokument, beskrives som ‘a section of thesteel polar cap (14 x 14 x 12 inches)’, og det andet beklædningsstykke var ‘a section ofthe MC-706 warhead ballistic case (3 x 1½ ft)’. Desuden var der den ﬂade, eksternekabelskinne, som vi har hørt omtalt tidligere, og endelig et stykke af et stållåsebånd.Sektionen af ‘stålkalotten’ beskrives i tre dimensioner med målene 36 x 36 x 31 cm ogmå antages at have været en rør- eller hætteformet del af yderbeklædningen. Stykketaf et sprænghoveds ballistiske hylster beskrives kun i to dimensioner med målene 92x 46 cm. I fortsættelse af spørgsmålene i vores tidligere ﬁngerede eksperiment kanvi nu konstatere, at de observerede dele faktisk blev identiﬁceret og beskrevet retnøjagtigt, men uden at blive bjerget.

På den vedhæftede skitse er der to koncentrationer af skrot, ‘A’ og ‘B’, med hver 3-4.000 små stykker. Det minder om Kofoed-Hansens beskrivelse, at B-52 var blevetsprængt i millioner af småstykker.Man kan ikke lade være med at tænke, at hvis marskalstaven havde ligget mellemalle disse stykker skrot, måtte det have været vanskeligt at ﬁnde den inden for dengivne tidsramme. Endvidere kan man foretage den mere ydmyge observation, at densavnede genstand omtales i ental. Det er, som vi forventede.Hen mod slutningen af notatet er der en interessant iagttagelse at gøre fra oriente-ringen ved de tre ﬂyveroﬃcerer. Det viser sig, at der opstod betydelig diskussion veddenne lejlighed af den uventede placering af det svære skrot i forhold til nedslags-stedet. Dette førte tydeligvis til videre spekulationer om, at den savnede genstand220

Samlet set må man dog sige, at der er beskeden opmærksomhed om marskal-staven, når man sammenligner med alle de andre emner, der tages op i notatet.Det bør endnu en gang understreges, at ingen kunne vide ved operationensplanlægning og udførelse, om cylinderen virkelig var på bunden, og om denvar ubeskadiget. Hvis den var, kunne den have været forvitret eller tæt påforvitring.Dokumentet nævner ﬁre våbendele på skitsen og siger, at der ikke var gjort andrevåbenfund, og at der ikke var observeret dele af secondaries, men var der alligevelandre fund? Vi har stadigvæk ikke fundet ud af, hvad der står i den måske 6-8linjer lange maskerede del af dok. 107072 af 27. august.Det var en noget udvandet version af de amerikanske dykninger, som chefenfor Thulebasen, oberst C.S. Dresser gav i den fælles dansk-amerikanske rapportProject Crested Ice,der udkom i 1970. ‘I august udførte danske og amerikanskevidenskabsmænd ved hjælp af en 54 fods dansk motorbåd, Aglantha, og en 24 fodsminiubåd, Star III, gentagne radiologiske undersøgelser og miljøundersøgelserlangs kysten af Wolstenholme Fjord for at sikre, at der ikke var nogen forureningtilbage i området’. ‘That’s All Folks!’, som de siger i slutningen af tegneﬁlmene, ogsom det stod malet med store bogstaver på enden af den sidste af de store tankemed kontamineret smeltevand, der blev sendt fra Thule, sådan som man ser pået billede med oberst Dresser i forgrunden. På den anden side bør artiklen rosesfor et godt billede af Star III med kloen fremme under næsesektionen (CrestedIce 1970: 30f ).Når vi antager, at general Gillers statusrapport ikke fortæller os alt om orienterin-gen i Walskes kontor, skyldes det, at der ikke er nogen omtale af det fund, som ermaskeret i dok. 107072. Videobåndene, der viser opsamlingen af en motorstøv-hætte, vidner tillige om Star III-observatørernes bemærkelsesværdige interesse forgenstande af ca. 50 cm’s længde. Først zoomer de ind på noget, der viser sig at væreet stykke ﬂadjern med skruehuller, omtrent en halv meter langt, men panorerervæk igen. Lidt senere bjerger fartøjet en genstand, som næppe er over en halv meterlang. Bortset fra motorstøvhætten er der ikke andre bjergningsforsøg på videoerne(HIAS 1988).‘Film 4 viser u-bådens klo, der fjerner en genstand, der kan være en motorstøvbeskyt-ter. Senere på samme ﬁlm fjerner kloen en anden uidentiﬁcerbar genstand, der næppeer mere end ca. ½ m lang’ (HIAS 1988).222

Denne interessante adfærd forekommer at passe godt sammen med Sandiasbeskrivelse af den manglende våbenkomponent og er således et yderligere tegnpå, at vi sandsynligvis var på rette spor i analysen af genstanden på grundlag afdok. 107032, og at det var denne form for genstand, amerikanerne ledte efter.At dømme efter de tilgængelige oplysninger, er det imidlertid sandsynligt, atden bjergede genstand ved nærmere eftersyn viste sig ikke at være den eftersøgtecylinder af uran 235.For lidt siden nævnte vi, at vi ikke ved, hvad der skjuler sig i den måske 6-8 linjerlange maskerede del af dok. 107072 af 27. august. Kunne det være en omtale af deneftersøgte genstand, cylinderen, som var blevet bjerget for derefter at blive afskrevetsom uinteressant?Hvis den bjergede genstand virkelig havde været den efterstræbte skat, villeder næppe have været en bemærkning i dok. 107057 om, at der ikke blevobserveret dele af secondaries. Endvidere ville der ikke have været grund tilat fundere over, ‘at den savnede [ord maskeret] på grund af sine ballistiskeegenskaber kunne være havnet hinsides den samling af tunge vragdele, manhavde iagttaget’.Gennemgangen af dokumenter vedrørende oprydningsoperationen i Grønland erhermed slut, men før vi forlader denne del af rapporten, skal vi se på et dokumentfra 1969. Det indeholder et skøn over, hvor meget plutonium der var i de tanke ogcontainere, som i 1968 blev sendt til Savannah River.9. juni 1969, dok. 107117Dokumentet er et fordelingsbrev med bilag til AEC’s formand og øvrige medlem-mer. Bilaget er et notat fra general Giller af 5. juni 1969, hvorfra klippet nedenforer taget.Notatets emne er indholdet af de containere med sne og is fra Thule, som varved at blive behandlet i Savannah River. Den 2. og 3. september 1968 var 315tanke på hver 1.800 gallons (6.814 l, i alt over 2 mio. l) blevet sendt fra Thule tilCharleston, S.C. (dok. 107059). Frem til 5. juni 1969 var det forurenede vand i225 af de 315 containere blevet ﬁltreret. Filtratet benævnes i dokumentet ‘soliddebris’. Sidste afsnit lyder: ‘Måling af residualplutonium 239 er gennemført, ogplutoniumindholdet i ﬁltrat skønnes at være fra 2,2 til 3,9 kg. Det skønnedeplutoniumindhold af al væske er mindre end 10 gram’.223

Dette sidste afsnit ser ud til at være sprogligt og indholdsmæssigt forbistret. Målingerog skøn er formentlig blandet sammen, eller i det mindste ikke holdt klart ude frahinanden. Den mest plausible læsning er at forstå dette sidste afsnit som et skøn forplutoniumindholdet i samtlige 315 containere, selvom en lille tvivl står tilbage om,at der menes det faktiske plutoniumindhold i 215 containere, snarere end et skønfor indholdet i alle 315.Det må dog rimeligvis antages, at Savannah havde mere præcise tal for det plutonium,der allerede forelå som ﬁltrat, og at de ikke ville have anvendt udtrykket ‘estimate’, hvisdet var en sådan konkret måling, der var tale om. Hvis det var en måling på ﬁltrat,som man havde lige foran sig, ville der vel ikke være en spredning fra 2,2 kg til 3,9 kg.Vi bemærker til støtte for fortolkningen af, at det handler om skøn for samtlige 315beholdere, at det i sidste sætning hedder, at det er detskønnedeplutoniumindhold foralvæske. Hvis teksten er så forkludret, som vi tror, er der imidlertid en vis modsigelsei at underkaste den så megen ﬁnfortolkning. Kan vi mon ikke regne med at væretilstrækkelig højt oppe i bureaukratiet til, at man ikke er interesseret i delresultater,men ønsker totale tal?Vi har således valgt den første fortolkning, som vi ﬁnder mest overbevisende. Talleneligger meget tæt på de tal, hvorom danske og amerikanske videnskabsmænd var enigeefter målingerne i Thule i 1968. Det er med andre ord kun af marginal betydning,om vi bruger disse tal eller resultatet af målingerne i Thule i overvejelserne om dentotale plutoniumbyrde i kapitel 5 og appendiks.224

For at illustrere, hvad der kan ske med kernevåben ved en ulykke, har vi fundet detnyttigt at anføre nogle få kendsgerninger om ulykken i Palomares. I nogle hense-ender er ulykkerne i Thule og Palomares identiske. De omfattede den samme typeﬂyvemaskine og den samme slags bomber. Men der er også forskelle. I Palomaresblev bomberne udløst fra ﬂyet før nedstyrtningen, nogle af dem med udfoldetfaldskærm, mens bomberne var inde i ﬂyet, da det styrtede ned i Thule. I Thuleblev dele af bomberne udsat for et gigantisk bål af jetbrændstof, mens dette ikkevar tilfældet i Palomares.Der havde været ni ulykker med kernevåben før Palomares, hvor det højeksplosivesprængstof i våbnene var detoneret. Imidlertid havde kontamineringen fra disse tidligeulykker været ringe med hensyn til radioaktivitet, og de berørte områder havde væretstærkt begrænsede. Alle disse ulykker fremskyndede udviklingen af et højeksplosivtsprængstof med lav følsomhed over for ekstreme omgivelser og af ﬁssile kerner, der varmodstandsdygtige over for brand og konstrueret til yderligere at formindske risikoenfor spredning af plutonium ved brand (Gregory 1990: 32; Drell & Peurifoy 1994:298-9, 301, 306-11; OTA 1993).Højeksplosivt sprængstof med lav følsomhed (IHE) kan bankes ind i hårde mål vedhastigheder, der overstiger 1500 f/sek. uden at føre til udløsning af nogen betyde-lig mængde af kemisk energi. Almindelige sprængstoﬀer frigør det meste af dereskemiske energi ved sammenstød ved hastigheder på 100 f/sek. Det formodes, atdetonationerne i Palomares ikke ville være sket, hvis sprænghovederne havde væretudstyret med IHE. Den nye type sprængstof blev første gang indført i arsenalerne i1979 (Drell & Peurifoy 1994: 308-9),20. januar 1966, dok. 1-6-4995. Telex til bl.a. Sandia. Foreløbig rapport om ulykkemed kernevåben.I den foreløbige rapport hører vi, at tre af kernevåbnene var blevet fundet påland. Den sidste bombe blev senere bjerget fra havbunden i en højt prioriteretoperation.Den første bombe havde fået en bule, men var intakt. Den anden og tredje bombevar hårdt beskadigede. Disse to bombers secondaries var brudt op, og primaries var226

RapportenBroken Arrow, Palomares,har følgende beretning om de tre kernevåben,der blev fundet på land.Våben nr. 1.Dette våben var i hovedsagen intakt. Afslutningspladen i halesektionenvar blevet revet af, da ﬂyet blev sprængt i stykker, og derved var faldskærmen blevetudløst. Der var en bule på 9 tommer i bombens næseparti, og den var blevet pressetnoget indad ved landingen. Tre af de ﬁre haleﬁnner var revet af. Sikkerhedskontak-ten stod på ‘safe’. Våbnenes lastekroge sad stadig fast i udløsningsmekanismen fraopbevaringsstativet.Våben nr. 2.Det højeksplosive sprængstof var eksploderet i en lavintensiv eksplosion.Bombens secondary blev fundet i et krater, der var omkring 6 m i diameter og 2 m idybde. Et beskadiget, men intakt reservoir blev fundet ca. 8 m fra krateret. Den ødelagtehalesektion og faldskærmspakken blev fundet ca. 90 m fra nedslagsstedet. En MildDetonating Fuze (MDF) havde fungeret, sandsynligvis ved nedslaget, og faldskærmen227

var [ulæseligt ord]. Hovedfaldskærmen hang ud af den ødelagte halesektion, men låstadigvæk i faldskærmsposen. Aﬀyringskomponenter og et kvantum højeksplosivtsprængstof blev bjerget i små stykker. Der var forurening med plutonium i området.Der blev ikke opnået nogen indikation på tritium med T-290 prøver.Våben nr. 3.Det højeksplosive sprængstof i dette våben var også gået af i en lavintensiveksplosion. Dele af det højeksplosive sprængstof blev bjerget. Våbnets secondary lå iet krater, der målte ca. [ulæseligt tal] fod i diameter og 1 m i dybden. Det smadredereservoir blev fundet 450 m fra nedslagsstedet. Halesektionen var nogenlunde intaktmed hovedfaldskærmen indeni. Afslutningspladen til halesektionen var tilsyneladendeblev revet af, da ﬂyet blev ødelagt, og styrefaldskærmen var blev udløst. Styrefald-skærmen var delvist brændt, hvilket havde betydet, at dette våben var faldet hurtigereend nr. 1. Der var forurening med plutonium i området.Yderligere information om, hvad der skete med våbnene i Palomares, ﬁndes i en kortartikel af Engineering and Analysis Division, Directorate of Nuclear Safety (BrokenArrow Aftermath. 1966: 2-6).Til vores formål er det første bemærkelsesværdige træk ved ulykken i Palomares denskæbne, som overgik våbnene nr. 2 og nr. 3 i form af en lavintensiv eksplosion af blotdele af det højeksplosive sprængstof. I begge disse tilfælde blev primaries nærmestfuldstændig ødelagt, og det uran 235 og plutonium 239, der var i primaries, blevspredt i partikelform, således som det kan ses i kontamineringens udbredelsesmønsterog intensitet.Såvel ved eksperimenter som i litteraturen er det påvist, at efter ulykker med eksplo-sioner og brand vil det ﬁssile materiale i primaries blive spredt i partikelform. Veden spredning af denne art vil partikelstørrelsen være lognormalt fordelt, dvs. at derelativt få, store (‘hot’) partikler vil være bærere af størstedelen af massen (aktiviteten).En konsekvens af en sådan spredning er, at aktiviteten vil være yderst heterogen, ogat det derfor er meget vanskeligt at foretage en repræsentativ indsamling af prøver(Eriksson 2005).Vi anser ligheden i omstændigheder samt partikelstudierne i Palomares og Thulefor at være en stærk indikation af, at de ﬁre primaries i Thule endte på samme måde,som det var gået de to eksploderende primaries i Palomares, at de to ulykker havdeeksplosionerne af det højeksplosive sprængstof til fælles. Blot var eksplosionerne iThule voldsommere end i Palomares, hvor de var lavintensive.228

I Thule forekommer det endnu mere sandsynligt end i Palomares, at alle ﬁre våben ereksploderet, fordi våbnenes hastighed ved nedslag var meget større, og fordi de lå vedsiden af hinanden, da de eksploderede. Desuden havde vi også den gigantiske brandi Thule. Eksplosionerne i Thule var tilsyneladende højintensive. Denne konstateringstøder man på i kilderne efter lidt tvivl lige i begyndelsen. Langhams rekonstruktionkunne godt pege i samme retning (dok. 107032, dok. 107038).Det andet bemærkelsesværdige træk ved våben nr. 2 og 3 i Palomares er, at selvomprimaries blev ødelagt ved de lavintensive eksplosioner, kunne de to secondariesbjerges, ganske vist i ødelagt eller beskadiget stand. Særligt kan det bemærkes, athalesektionen med faldskærmspakken og tritiumreservoiret synes at have været etsvagt punkt i konstruktionen.Den undersøiske bjergningsoperation vedrørende våben nr. 4 i Palomares var i enmange gange større skala end undervandsoperationen i Thule, se dok. 107036, Annex1. Denne kendsgerning er endnu en udmærket indikation af, at undervandsopera-tionen i Thule ikke handlede om et kernevåben, en bombe, men om noget megetmindre, og mindre vigtigt.I Palomares undersøgte en mængde scubadykkere de lavvandede dele af området, enundervandsbåd tog de mellemste dybder, og undervandsfartøjer, et ved navn Alvinog et andet ved navn Aluminaut, undersøgte det dybe vand. Våbnet blev lokaliseretca. tre uger senere af Alvin. Efter at våbnet var blevet lokaliseret, benyttede man etnyt ubemandet undervandsaggregat kaldet Curv. Curv var fuldautomatisk medstore, krabbeagtige kløer, tv-kameraer og projektører. Bomben blev bjerget den 7.april 1966, 80 dage efter ulykken (dok. 107036).

Skøn over bjergede våbendeleEt fuldstændigt skøn over bjergede våbendele kan ikke gives, eftersom de ﬂeste af derelevante dokumenter stadigvæk er klassiﬁcerede eller maskerede. Alligevel kan noglevigtige data og oplysninger trods alt presses ud af de tilgængelige kilder.Vi vil ikke forsøge i dette kapitel at opstille en liste over de bjergede våbendele, somvi har diskuteret på de foregående sider. I stedet vil vi koncentrere os om visse træk,der fremstår som særligt betydningsfulde i denne henseende. Det kan være våbendele,som er bjerget, dele, der ikke er bjerget, og spørgsmål om fortolkningen. Disse trækbliver diskuteret i følgende orden, som er dikteret af de tre hovedsektioner i våbnene:halesektionen, secondary og primary.Bag denne analyse og forhåbentlig i de ﬂeste tilfælde nådigt skjult for læserens øjneligger der en kombination af forskellige metoder, f.eks. analyser af beslutningspro-cessen i København og Washington; analyser af fund og ikkefund af våbenkompo-nenter; vurderinger af type og mængde af ﬁssilt materiale i primaries og secondaries;en sammenligning med lignende ulykker, specielt den i Palomares; samt brug af dehistoriske hjælpevidenskaber på dokumenterne, arkiverne, den bureaukratiske procesog andre omstændigheder.Halesektionerne.For at tage det mest oplagte først, er det uforståeligt, at de,der har hævdet, at SN 78252 lå på havbunden, ikke har bemærket det faktum,at en af de vitale dele af denne bombe, tritiumreservoiret, blev bogført tidligt ieftersøgningsoperationen og identiﬁceret med denne bombe. Dette bevis er noktil at sige os, at alle ﬁre våben blev ødelagt. Tritiumreservoirerne sad i våbneneshalesektion, men tjente det formål at forstærke ﬁssionsprocessen i våbnenesførste trin, primary. Dette gør rede for halesektionen i alle våben uden nogetbehov for at diskutere det yderligere bevis vedrørende faldskærmene, som blotpeger i samme retning.Secondaries.Det mest bemærkelsesværdige er påvisningen af, at det, amerikanerneledte efter i undervandsoperationen, ikke var den meget omtalte bombe SN 78252,men marskalstaven, uran 235-staven i en secondary. Star III-undervandsfartøjetfandt et objekt, der tilsyneladende passede med den beskrivelse, som vi har vredet ud230

af Sandias rapport, dok. 107032, men ved nærmere eftersyn blev det formodentligklart, at dette ikke var den eftersøgte genstand.En AEC-analyse, som citeres i klippet nedenfor, siger, at 85 procent af den uran,der var i tre secondaries, blev bjerget. Når man tager de anstrengelser i betragtning,der blev investeret i at bjerge netop uran 235 fra secondaries, kan det være, at detteprocenttal udelukkende refererer til uran 235 i de ﬁssile kerner af secondaries,men vi kan ikke være sikre. Noget af denne mængde blev tilsyneladende fundetsom intakte kerner, andre dele i små fragmenter. Vi antager, at det ikke altid varmuligt at identiﬁcere disse stykker af uran 235 med noget speciﬁkt våben og måholde muligheden åben for, at de kunne være kommet fra et hvilket som helst afde ﬁre våben.Således udgør det manglende uran 235 fra secondaries måske 15 procent af mæng-den fra tre våben plus 25 procent for de ﬁre våben tilsammen Men vi kan ikke væresikre på, at amerikanerne var i stand til med fuld sikkerhed at sige, fra hvilke våbenhvert og et af de bjergede stykker stammede. Hvis det er korrekt, betyder det, at dehandlede på formodninger mere end sikkerhed, når de kiggede efter et helt stykkeuran på havbunden, selvom de måske har haft supplerende indikationer, som kanhave fået undervandseftersøgningen til at se lovende ud. Dr. Walske ser dog ikkeud til at have troet særlig meget på nødvendigheden og nytten af undervandsef-tersøgningen.Denne analyse af jagten på de ﬁssile kerner i secondaries har mange vigtigekonsekvenser. Lad os nævne blot to af dem. For det første går den stik imodenhver tanke om en eftersøgning af en bombe ved at fortælle os, hvad det varamerikanerne i virkeligheden ledte efter. For det andet er den, ved at give os enantydning af, hvor svært beskadiget secondaries var, primært som et resultat afeksplosionerne, et bevis til støtte for den version, at alle ﬁre primaries blev ødelagti konventionelle eksplosioner, hvorved alt plutonium og uran i primaries blevspredt i partikelform.Vi mener, at så mange dele af secondaries blev bjerget, at det gør det usandsynligt,at SN 78252 ikke skulle have bidraget til denne samling af bjergede genstande,som i AEC’s regnskab udgjorde 94 procent i vægt af tre secondaries, mens vi i detamerikanske luftvåbens beretning hører, at ‘unummererede dele af secondaries blevfundet vidt spredt. Disse dele udgjorde mindre end tre komplette secondaries’.Den stakkels mand, der har anbragt disse tilsyneladende inkonsistente sætninger231

ved siden af hinanden i den korte artikel ‘Broken Arrow – Thule’, kunne ikke ane,med hvilken interesse hans prosa ville blive undersøgt 40 år senere. Overﬂadiskset siger de to sætninger mere eller mindre det samme, men når man bemærker, atluftvåbnets opgørelse alene regner med de unummererede dele, hvorimod AECtaler om [alle?] bjergede komponenter fra secondaries, begynder spørgsmåleneat melde sig.Taget bogstaveligt betyder luftvåbnets beretning, at vi skulle lægge de nummererededele oven i de unummererede, og hvad ville vi så få? 99 procent eller hvad? Som vived, blev en af secondaries fundet relativt intakt og identiﬁceret ved nummer. Deleaf to andre secondaries blev også identiﬁceret ved nummer. Vi er ikke i stand til atsige, om denne tilsyneladende inkonsistens mellem disse to skøn dækker over nogenskjult dybere mening, eller om den er et resultat af manglende omhu. For resten er detslet ikke nødvendigt at løse denne lille gåde. Beviserne for, at alle ﬁre secondaries giki stykker, er under alle omstændigheder overvældende, nogle af dem særdeles megeti stykker, andre ikke så meget.Det afsnit i ‘Broken Arrow – Thule’, som vi har diskuteret her, slutter med en afde sætninger, der igennem årene er blevet brugt af medierne til støtte for tankenom en bombe på havbunden. Den lyder: ‘Ingen dele af den fjerde secondary erblevet identiﬁceret’. Det er vist nok at sige, at det er en logisk fejl heraf at slutte,at så ﬁndes der nok en bombe et sted. Når man i udgangspunktet har ﬁre secon-daries og kan identiﬁcere tre af dem ved hjælp af nummererede dele, og samtidighar mange unummererede dele af secondaries, som man ikke kan identiﬁceremed nogen af de ﬁre våben, så følger det ikke deraf, at ingen dele af den fjerdesecondary er blevet fundet, eller at den fjerde secondary er hel. Disse ‘anonyme’dele kan simpelthen blot ikke henføres til et speciﬁkt våben, hvilket ikke er detsamme, som at de ikke er blevet fundet. De kunne komme fra en hvilken somhelst af de ﬁre bomber.Tag det eksempel, at man taber ﬁre identiske glasvaser fra et ﬂy over det frosne BylotSund og derefter tilføjer en snestorm, nogle eksplosioner, et gigantisk bål og et huli isen. Så starter man en meget omhyggelig eftersøgning efter fragmenter af vaserneog har til sidst bjerget 94 procent af vægten af tre vaser. Ved et lykketræf er man istand til at sætte nogle få af de fundne stykker sammen til tre noget større stykker,som dog ikke passer sammen indbyrdes. Derved har man konstateret, at tre vaser varblevet ødelagt.

Men der ligger stadigvæk en stor dynge glasskår på bordet. Uanset hvor meget mananstrenger sig, har man ikke held til at sætte nogen af disse tilbageværende stykkersammen. Ville man så begynde at tænke, at den fjerde vase stadig var hel? Ville manhævde, at det følger af, at man ikke er i stand til at samle et fjerde fragment, at en helvase eksisterer? Det kunne man selvfølgelig hævde, men det ville være en logisk fejl.Ingen ville formodentlig fremsætte denne påstand, bortset fra den uretfærdige herre,som siger til sin tjener, at nu har han gjort rede for tre vaser, men derefter beskylderham for at have stjålet den fjerde. Hvis man i stedet godt kan lide at tænke på helevaser, ville man sige, at det ikke kunne udelukkes, at en hel vase eksisterede et ellerandet sted.Statistisk er det imidlertid meget mere sandsynligt, at nogle af de uidentiﬁceredestykker af secondaries hørte til den fjerde bombe. Man behøver kun at tænkepå de mange tusinde stykker vraggods, der blev rapporteret fra havbunden, forat indse, hvor usandsynligt det ville være at nå tallet på 94 procent for tre se-condaries uden at inddrage dele fra SN 78252, dele, der ganske vist ikke kunneidentiﬁceres med SN 78252. Men dette var imidlertid ikke noget eneståendefor SN 78252. Som nævnt blev mange småstykker identiﬁceret som hørendetil secondaries, men kunne ikke tilordnes nogen speciﬁk bombe og var i denforstand uidentiﬁcerede.Primaries.Vi har også argumenteret for, at alle ﬁre primaries blev fuldstændig øde-lagt af eksplosionerne af de betydelige mængder af højeksplosivt sprængstof, dervar placeret rundt om den ﬁssile kerne i primaries. Det eneste eventuelle vraggodsfra primaries, som vi er opmærksomme på, er ﬁre stykker skrot, der blev fundet påhavbunden, men ikke bjerget. I Thule har vi, i modsætning til i Palomares, ikke nogenindikationer på, at der blev fundet uidentiﬁcerede fragmenter af det højeksplosivesprængstof fra primaries. Dette er endnu et tegn på eksplosionernes ødelæggende kraftog gør ødelæggelsen ikke blot af primaries, men i varierende grad også af secondariesyderligere plausibel.Et meget kortfattet, men i visse henseende nyttigt overblik over bjergede våbendeleﬁndes i den korte artikel ‘Broken Arrow – Thule’, der er skrevet af Weapon SystemsDivision, Directorate of Nuclear Safety, in USAF Nuclear Safety, Classiﬁed Section,AFRP 122-1, Jul-Aug-Sep 1968, No. 3, Volume 60 (Part 1), pp. 2-5. Oversigten kandownloades fra http://www.dod.mil/pubs/foi/reading_room/133.pdf

nødvendigvis afspejlede hele plutoniumindholdet i våbnene – men måske snarerekunne forstås som et skøn over det oprindelige niveau for plutoniumforureningen iThuleområdet. Vi må indrømme, at vi som udgangspunkt var skeptiske med hensyntil nøjagtigheden af denne mængde som udtryk for det totale indhold af plutoniumi våbnene, men gradvis er vi blevet overbevist om, at tallet 6 kg er en ganske godtilnærmelse eller en ‘rounded-oﬀ value’, som dr. Walske udtrykte det i sit energiskeforsvar for at give dette tal til danskerne – i den lave ende af det virkelige tal, dersandsynligvis er tættere på 7,5 kg.Imidlertid skal Walskes elegante bureaukratiske kompromis og diplomatiske håndværkikke få os til at tro, at Den Hellige Gral ikke eksisterede mere. Tekniske speciﬁkatio-ner vedrørende indholdet af de ﬁre bomber på B-52 blev stadigvæk anset for ‘secretrestricted data’. Dette blev tydeligt illustreret på et møde i Washington i slutningen afaugust 1988 mellem repræsentanter for den danske sundhedsstyrelse og amerikanskeembedsmænd. Mødet vedrørte danske spørgsmål om mængden og karakteren af detudspredte radioaktive materiale, specielt indholdet af bomberne og mængden afplutonium på de vragdele af ﬂy og bomber, der blev sendt tilbage til USA i 1968.En noget oprømt embedsmand fra State Department sagde i en blomstrende demon-stration af diplomatisk omnipotens, ledsaget af melodramatiske fagter, at chancen for,at den danske delegation ville få denne information, var nogenlunde den samme, somat alle iltmolekyler i rummet ville samle sig i et hjørne under loftet. Stadig med lidtkræfter i behold fortsatte embedsmanden med at erklære, at State Department ikkefandt at have nogen forpligtelse til at besvare den danske sundhedsstyrelses spørgsmål,eftersom de i amerikansk forståelse ikke var udtryk for en oﬃciel henvendelse fra dendanske regering gennem de dertil indrettede kanaler.Denne kompromisløse holdning blev imidlertid blødt op syv år senere i nogle fåsætninger iFinal Response to Danish Questions.Hvis disse sætninger havde udgjorten del af et nyfundet håndskriftsfragment af Den Hellige Skrift, antager vi, at derville være vokset en solid eksegetisk litteratur frem omkring dem. Men da denne teksttrods alt ikke stammer fra Gud, men en bureaukratisk maskine, er disse sætningertilsyneladende ikke blevet bemærket så meget, som de måske fortjener.Her er, hvadFinal Responsesiger: ‘At the time of the accident, the US furnished theDanish scientists with a very reasonable estimate – 6 kilograms – of the actual amountof plutonium involved in the four weapons’ (answer 2) og ‘the Danish scientists hadbeen informed as early as April 1968 that the four nuclear weapons involved in the237

Thule accident contained a total of about 6 kg of plutonium’ (answer 9). Når manførst er blevet opmærksom på disse nye formuleringer, er det tydeligt, at de er megetforskellige fra den traditionelle formel, der lyder: ‘The fact that approximately 6 kgof plutonium were involved in the Greenland accident’ (answer 8) (FinalResponse1995).Læseren vil bemærke, at de opﬁndsomme koncipister har moret sig med at ﬂytteordet ‘involved’ rundt i sætningerne som for at undersøge, hvor mange varia-tioner og transformationer dette lille uskyldige ord kunne underkastes, før detfuldstændig mistede sin mening. For at dække denne dristige leg med ordene erde forskellige versioner omhyggeligt placeret i svar, der ligger på sikker afstandfra hinanden.Begrundelsen for den nærmest tvangsprægede brug af ordet ‘involved’ i disse sæt-ninger er tydelig. Det er en lille ansigtsreddende mekanisme, der skal sløre det til-syneladende pinlige faktum, at en 27 år gammel formulering med dogmatisk statuser blevet ændret.Vi bør naturligvis ikke beklage dette bureaukratiske broderi, eftersom slutresultateter yderst tilfredsstillende. Sandsynligvis for første gang i USA’s historie var et oﬃcieltdokument kommet så tæt på at afsløre indholdet af plutonium i konkrete våben, somman kan forvente. De relevante afsnit fortjener en fremkaldelse: ‘Danish scientistshad been informed as early as April 1968 that the four nuclear weapons involved inthe Thule accident contained a total of about 6 kg of plutonium’ og ‘At the time ofthe accident, the US furnished the Danish scientists with a very reasonable estimate– 6 kilograms – of the actual amount of plutonium involved in the four weapons’.Uden tvivl må disse anstrengelser være blevet godkendt af Director of Classiﬁcationi Department of Energy, og de fortjener deres retmæssige plads på DOE’s websitemed dets lange lister af små ting, som man kan sige om kernevåben.Også en anden detalje er værd at notere. Det synes at være meget vigtigt at understrege,at tallet 6 kg (om våbnene) har været brugt hele tiden, lige siden 1968. Det er der en vissandhed i, som vores henvisning til Asker Aarkrogs dagbog viser, og det er selvfølgeliglige så sandt, at yndlingssætningen: ‘The fact that approximately 6 kg of plutoniumwere involved in the Greenland accident’ blev meddelt de danske myndigheder ogvidenskabsmænd i 1968. Brugen af ‘1968’-eksempler i disse sætninger udgør, tror vi,endnu et forsøg på at skabe det indtryk, at alt dette har man sagt mange gange før,238

og at det gentagne gange er blevet bekendtgjort lige siden ulykken, hvilket dog ikkeer tilfældet, da det er noget andet, man har sagt. Den formentlig utilsigtede sideef-fekt af denne argumentationsform er at slippe associationer løs om, at danskerne måvære en smule tungnemme. Det vigtigste er dog sikkert stadigvæk sløringen af, atformuleringen er ny.Man kan konkludere, at dette var et meget velkomment gennembrud i amerikanskeerklæringer om mængden af det plutonium, der var blevet spredt ved Thuleulykken,og det synes samtidig at støtte vores fortolkning af, hvad det var, Walske prøvede atopnå dengang i april 1968.Lige så meget som alt det ovenstående kan være af interesse for aﬁcionados af detdiplomatiske sprogs labyrinter, synes det i praktisk henseende at være et spørgsmålom 1 eller 2 kg plutonium mere eller mindre. For så vidt angår den del, der vedrørerdet diplomatiske sprog, ville Osvald Helmuth og John Wayne sikkert have trukketpå skuldrene.Det er skæbnens ironi, at dr. Walskes opﬁndsomme og vidtskuende kompromisikke har haft den beroligende eﬀekt, som var hensigten. I oﬀentligheden har detteproblem ført til spørgsmål blandt både danskere og grønlændere, fordi almindeligeopslagsværker og DOE’s egen hjemmeside om spørgsmålet til denne dag opererermed 6 kg plutonium pr. våben som minimum. I ﬁre våben ville det betyde 24 kg. PåDOE’s hjemmeside anføres dog i dag også tallet 4 kg for moderne våben. (Disse taltager ikke hensyn til, at man blandede uran 235 og plutonium, og derfor fører detankerne på afveje).Folk ville så begynde at stille spørgsmål. ‘Hvis myndighederne siger, at 6 kg pluto-nium var indblandet i ulykken, og at alle ﬁre våben eksploderede i en konventioneleksplosion, hvor er så de 18 kg blevet af ?’. Dette har ført til en opfattelse af, at derkunne være manglende sammenhæng mellem de oﬃcielle tal og de virkelige tal, og atder enten kunne være mere forurening end meddelt af myndighederne, eller omvendtat nogle af våbnene ikke var blevet ødelagt ved ulykken og derfor stadigvæk kunneligge på havbunden.På den måde er der, til trods for mange oﬃcielle forklaringer gennem årene, stadigvæken opfattelse af, at der måske eksisterer en eller anden uafklaret risiko, enten i form afen højere grad af kontaminering end angivet, eller i form af stadigvæk eksisterendebomber.239

Vi foregiver ikke at vide nøjagtigt, hvor mange kg plutonium der var i bomberne.Det drejer sig i denne rapport ikke om fuldstændig præcision, men om, hvorvidtmængden er tættere på virkeligheden end fantasien. Så længe der er nogen, deropererer med et spænd mellem 6 kg og 24 kg, er der ikke udsigt til, at troværdig-hedskløften mellem regeringsforklaringer og opfattelser i oﬀentligheden forsvinderaf sig selv.Vi mener at have fundet en plutoniummængde tæt på virkeligheden og at havefundet fælles grund – med et epicenter omkring 7,5 kg. Dvs. 7,5 kg i våbnene ogdermed 7,5 kg spredt ved eksplosionerne. Tilnærmelser naturligvis, men tæt på,hvilket betyder, at vi igen kan begynde at tale om realiteter og genetablere nogetaf den tabte tillid.Det er derfor med en vis tilfredshed, at vi er i stand til i denne rapport at fremlæggeet sådant skøn over plutoniummængden, at det måske kan afbøde nogle af de be-kymringer og mistanker, som har været en faktor i Thuleulykkens historie i mere end40 år. For at øge tilliden, få bedre monitering og skabe forbedrede betingelser forforskningen har vi brug for frigivelse af ﬂere data, f.eks. vedrørende slutresultaterneaf målingerne af ﬁltratet på Savannah River, af skrot i igloen på Thule, af ﬂyskrot ialmindelighed og af de bjergede våbendele på Rocky Flats og andre steder (jf. f.eks.dok. 104812 og dok. 104813). Der mangler ikke nogen bombe, men der manglerdokumenter. Heldigvis har DOE erklæret, at forslag fra oﬀentligheden er velkomnemed hensyn til, hvordan ministeriet kan frigive information, der er af legitim interessefor oﬀentligheden og samtidig opretholde kontrol med oplysninger, der er vigtigefor den nationale sikkerhed (DOE 1996; jf. Chu 2009).Den første oplevelse afheurekai denne del af undersøgelsen var resultatet af et simpeltopslag i standardværketWorld Inventory of Plutonium and Highly Enriched Uranium1992:2 kg plutonium i tidlige våben, sagde det (WorldInventory1992 ). Hidtil synesde ﬂeste at have opereret med tallet 6 kg plutonium pr. våben, og der er tilsyneladendeikke nogen, der har lagt mærke til, at DOE i 1994 afklassiﬁcerede tallet 4 kg som detteoretiske minimum for moderne våben, hvilket antagelig betyder våben i 90’erne.Denne information har været frit tilgængelig i omkring et tiår. Det er et godt eksempelpå, hvor opsplittet i specialiserede båse information er blevet.Derefter dukkede andre småstykker frem og pegede i samme retning. De fremlæggesi appendiksets tabel 1. I tabel 2 anføres skøn og målinger for plutonium spredt vedeksplosionerne.240

Det andetheurekakom sent. I slutfasen af undersøgelsen begyndte et af de dokumenter,som historikere godt kan lide at kalde kronjuveler, pludselig at tale. Kronjuvelen vardenne gang to linjer med tre tal i det håndskrevne referat fra et møde i Washingtonden 5. februar 1968 (dok. 107152).På grundlag af disse to linjer nåede vi frem til ca. 7,5 kg for de ﬁre våben.Efter ﬂere årtiers diskussion har vi etableret en plausibel sammenhæng mellem denmængde plutonium 239, som blev spredt i miljøet eller hamret ind i våben- ogﬂyskrot ved de konventionelle eksplosioner i primaries og mængden af plutonium239 i våbnene.Dette er et gennembrud i udforskningen af ulykken, selvom det ikke har været denhøjere videnskab at nå til resultatet. Betydningen ligger i, at den overensstemmelsemellem tallene, der er etableret på grundlag af uafhængige kilder og et lille stykkeucensureret oﬃciel information, kan være med til at fjerne grundlaget for at tvivlepå de oﬃcielle forklaringer om, hvad der skete, og derved starte en proces til genop-bygning af tilliden i dette spørgsmål. Vi kan imidlertid ikke på det grundlag aleneopstille det endelige plutoniumregnskab. Det er en opgave for myndighederne ognaturvidenskaberne.

Forsøget på en historisk rekonstruktion af begivenhederne i Thule i 1968 er gjortmed det formål at afprøve forskellige forklaringer på, hvad der skete med de ﬁrekernevåben, der indgik i ulykken.Til indledning er det vigtigt at bemærke, at vi ikke har noget fuldt kendskab til devåbenkomponenter, som blev bjerget i Thule. Så vidt vi ved, er ingen af de mereomfattende oversigter over bjergede våbendele tilgængelige. Den korte, maskeredeoversigt i Department of Defenses FOIA-læsesal er mildest talt kortfattet, mendog nyttig. Mange af de genstande, der er nævnt i de dokumenter, som er gjorttilgængelige, er maskerede. Maskeringerne har tilsyneladende næsten alle nogetat gøre med våbendesign, våbendata, kommunikation og andre klassiﬁceredeoplysninger.Et af de mest følsomme emner blandt de klassiﬁcerede data var mængden af pluto-nium 239 i de ﬁre våbens primaries. Også mange andre aspekter af våbendesignetblev anset for at være hemmelige. Dette er stadigvæk tilfældet, og de ﬂeste kanformodentlig se berettigelsen af at holde nukleare hemmeligheder tæt til kroppen.Men som vi har vist, så afklassiﬁcerede den amerikanske regering faktisk i 1968,i en let sløret form, et tal for den totale plutoniummængde i våbnene, som varnæsten korrekt.Da dette talt blev oﬀentligt kendt, var der knap nok nogen, der troede på det. Af detkan man tilsyneladende lære, at det er sikkert at oﬀentliggøre sine hemmeligheder,så længe man blot gør nogle mindre vigtige maskerede dokumenter tilgængeligesamtidig. Resultatet af denne intrikate blanding af åbenhed og hemmeligholdelsekan medføre så stor forvirring, at man ikke bliver taget på ordet, især ikke når mansiger sandheden.Paradokset ved hemmeligholdelse i en demokratisk stat er, at hemmeligheder har entendens til at underminere borgernes tillid til den selv samme stat, som eksisterer for atbeskytte dem og har brug for hemmeligheder for at gøre det. Vi bedrager os selv, hvisvi tror, at den subtile balance mellem transparens og hemmeligholdelse kan deﬁneresklart, og at visdommen til at administrere denne balancebona ﬁdei oﬀentlighedensinteresse altid er til stede.

Hvad skete der med bomberne?Det spørgsmål var udgangspunktet for rapporten. Vi har også haft skuﬀelser i voreseftersøgning af bomberne. Ved begyndelsen af undersøgelsen etablerede vi to ‘teorier’som ramme for arbejdet med dokumenterne. De to ‘teorier’ var rene konstruktioner,der var tænkt som enkle redskaber, der skulle hjælpe med at analysere begivenhederne.Efter nogle udkast måtte vi opgive denne metode, da det viste sig, at den blot førtetil unødvendige gentagelser.For at arbejdet i den indledende del af undersøgelsen ikke skal være spildt, vil vi doggive læseren et kort glimt af vores første mislykkede skridt i processen. Vi kaldtede to redskaber for 4-bombeteorien og 1½-bombeteorien for ikke at stå tilbage forBBC og har illustreret dem med ikonerne nedenfor, som viser de tre hoveddele afvåbnene, primary, secondary og halesektionen. De små kryds viser, at der er gjortrede for våbnene, dvs. at de enten er ødelagt eller bjerget.

Her slutter sammenfatningen af beviserne vedrørende de ﬁre kernevåbens skæbne.Påstandene om en ‘manglende bombe’ – som på egne præmisser korrekt burde lydeen ‘manglende secondary’ – er blevet fremsat med regelmæssige mellemrum siden1987. I de senere versioner byggede de på to søjler, 1) at ingen af de unummererededele af secondaries kunne matches med bombe SN 78252, 2) at usikkerhed, rygterog en vis mængde hemmelighedsfuldhed omgav Star III’s dykninger.Anden del af argumentet er nu erstattet af viden. Vi ved, at amerikanerne ledteefter marskalstaven. Uden støtte fra den anden søjle krakelerer den første søjleunder vægten af sin egen logiske fejlslutning og de beviser, der er blevet fremlagti denne rapport.

Om kilderneUdenrigsministerens speciﬁkke spørgsmål til DIIS var, om de 348 dokumenter, somBBC-journalisten Gordon Corera havde modtaget i 2001, indeholdt afgørende nyeoplysninger sammenlignet med de 317 dokumenter, der blev afklassiﬁceret af detamerikanske energiministerium (DOE) fra 1986 og frem, og som blev gjort tilgæn-gelige i september 1994.Der blev ikke fremsat nye dokumentbaserede påstande om bomberne i 2008, oggrundlaget var stort set det samme som de dokumenter, der var blevet gjort tilgængeligeaf DOE i 1994 og brugt i år 2000 i en artikel iJyllands-Posten.BBC’s anden påstandom, at der var blevet tilbageholdt oplysninger vedrørende undervandsundersøgelsensegentlige formål, kan man kalde en ny nyhed, hvis man tænker på mediedækning,men den grundede sig på et gammelt velkendt dokument, der var blevet afklassiﬁcereti februar 1991 og var en del af 317-samlingen.Denne rapport bygger i hovedsagen på 348-samlingen, dvs. de samme amerikanskedokumenter, der i mange tilfælde blev afklassiﬁceret for næsten 20 år siden, menanvender desuden nogle få dokumenter fra danske og andre arkiver. Det nye i dennerapport er med andre ord ikke så meget kilderne som analysen og fortolkningen affor det meste velkendte dokumenter.

faktum, allerede fordi deuterium/tritium-reservoirerne i de ﬁre våbens halesektionerbrækkede af ved nedslaget og blev bjerget tæt ved nedslagsstedet.Vi kan give et klart svar: Der er ikke nogen bombe, der var ikke nogen bombe, ogamerikanerne ledte ikke efter nogen bombe.Vi har fundet stærke indicier for, at alle ﬁre primaries blev ødelagt i konventionelleeksplosioner ved nedslaget. Primaries er bombernes første trin.Det plutonium, der var i de ﬁre våbens primaries, blev spredt i partikelform vedeksplosionerne og den følgende brand.Dette er i alle vigtige henseender sammenligneligt med, hvad der skete i de ganskevist kun lavintensive eksplosioner af det højeksplosive sprængstof i to af bombernei Palomares-ulykken to år tidligere, og stemmer ligeledes ganske godt overens medde konsekvenser, dette havde for secondaries og for karakteren af de spredte aktivepartikler i Palomares.Vi har ligeledes argumenteret for, at alle ﬁre secondaries blev ødelagt, men ikke ialle tilfælde med de samme tilintetgørende konsekvenser for disse sektioner som forprimaries.

Om plutoniumIndtil nu har der været nogen tvivl i oﬀentligheden med hensyn til, om alle ﬁre pri-maries virkelig eksploderede. Denne skepsis skyldtes tanken om, at der var manglendeoverensstemmelse mellem de 24 kg plutonium, som man har ment var nødvendigefor at nå en kritisk masse i de ﬁre primaries tilsammen, og de ca. 6 kg, der ifølgemyndighederne var involveret i ulykken.Skeptikere i oﬀentligheden ville så sige, at enten eksploderede ikke alle ﬁre primaries(hvilket efterlod muligheden for en ‘manglende bombe’), eller at der ikke var gjortkorrekt rede for de formodede 24 kg (med den konsekvens, at kontamineringen varværre, end man indrømmede).Vi mener efter ﬂere årtiers diskussion at have fastslået, at den mængde plutonium239, der blev spredt som meget små partikler ved de konventionelle eksplosioner afvåbnene, nogenlunde svarer til den mængde plutonium 239, som var i våbnene.249

Dette er et gennembrud i udforskningen af ulykken, selvom det ikke var nogenhøjere videnskab at nå frem til dette resultat. Dets vigtighed ligger i, at kor-respondancen mellem tallene kan fjerne grundlaget for at betvivle de oﬃcielleforklaringer om, hvad der skete, og kan markere en ny begyndelse i genopbyg-ningen af tillid i dette spørgsmål. Vi kan imidlertid ikke på det grundlag aleneopstille det endelige plutoniumregnskab. Det er en opgave for myndighederneog naturvidenskaberne.Dette resultat, enkelt som det er, var et afheureka-øjeblikkenei undersøgelsen. Ogsom det sommetider sker, lå løsningen ligefor. Efter i ugevis at have konsulteret lit-teraturen og eksperter på forskellige områder uden resultat vendte vi os endelig tilnedrustningslitteraturen.Som referenceværdi angav den rundt regnet 2 kg plutonium 239 pr. våben. Derefterbegyndte en række andre informationer, der pegede i samme retning, at komme optil overﬂaden.Kronjuvelen i den henseende var to linjer med tre tal i det håndskrevne referat fra etmøde i Washington den 5. februar 1968. På grundlag af disse to linjer nåede vi fremtil ca. 7,5 kg plutonium for de ﬁre våben tilsammen.I 1950’erne og 1960’erne bestod den ﬁssile kerne i våbnene af store mængder uran 235og relativt små mængder plutonium 239. Standardreferenceværdien for plutonium239 i våben af den generation er ca. 2 kg. I senere våben, hvor mængden af uran iblandingen blev formindsket eller fjernet, voksede mindstemængden af plutoniumtil måske 4 kg. Tallet 4 kg for moderne våben blev afklassiﬁceret af de amerikanskemyndigheder i 1994.

Om undervandsoperationen og den ‘manglende komponent’Der er ikke efterladt nogen kernevåben på havbunden i Thule. Der er heller ikkeefterladt nogen secondary i havet. Argumenterne er opregnet i sammenfatningen afbeviser i kapitel 6, blandt dem det faktum, at vægten af næsten tre secondaries (94pct.) blev bjerget og sendt til USA. Mange af secondarystykkerne var små og unum-mererede og blev fundet vidt spredt på isen.At nå frem til samlet 94 procent af vægten af tre secondaries forekommer usandsyn-ligt under omstændighederne, hvis der kun havde været tale om opsamlede stykker250

fra tre våben. Det er meget mere sandsynligt, at tallet på 94 procent blev nået ved atindsamle stykker fra alle ﬁre secondaries.Allerede i april 1968 havde de amerikanske myndigheder sandsynligvis et udmærketbillede af, hvad der var sket med alle ﬁre secondaries. Hvis ikke, ville det være uforstå-eligt, at de kunne bede Sandia Corporation om at fastlægge banerne i vandet i BylotSund for en særlig, særdeles veldeﬁneret våbenkomponent. Kun én komponent, oghelt sikkert fra en secondary. Dette er den anden juvel i undersøgelsen.Vi mener, at amerikanerne søgte efter marskalstaven, den ﬁssile kerne i en secondary,ofte kaldet tændrøret. Genstanden var cylinderformet med afrundede ender.Dens strømningsmodstandskoeﬃcient blev af Sandia Corporation beregnet til atvære 0,6 lige på og 1,0 med siden til. Det kan have været en massiv stav, men deter langt mere sandsynligt, at det var et rør med forseglede ender. Kilderne givermange beviser for, at sådanne stykker blev samlet op på isen i februar og marts1968, og at jagten på resterende stykker fortsatte til slutningen af operationen iaugust 1968.Der er mange beviser på, at marskalstaven indeholdt uran 235. Vi tror, at dokumen-terne henviser til marskalstaven, som en ‘secondary pit’ og en ‘oralloy pit’, selvom dertilsyneladende ikke er nogen eksperter, der husker eller kender denne terminologi.Hvis vi antager, at marskalstaven indeholdt 8 kg uran 235, ville den have et volumenpå ca. 4 dl. En cylinder med dette volumen kunne f.eks. være 50 cm lang med endiameter på 3,3 cm, noget tykkere hvis den var et rør, f.eks. 5,4 cm med en vægtyk-kelse på 1,1 cm.Dette er en ret lille genstand at ﬁnde på havbunden, især hvis man tager i betragtning,at den kunne være gået i stykker og ligge mellem tusindvis af andre stykker skrot efterulykken. Den er dog større end tændrøret i en bil. Vi har derfor valgt at kalde denmarskalstaven. Størrelsen passer bedre.At det virkelig var en genstand af omtrent denne størrelse, som det amerikanske StarIII-undervandsfartøj var på udkig efter, bliver klart i videooptagelserne fra dykningerne,hvor en klo bjerger et objekt, der passer med beskrivelsen. Ved nærmere undersøgelseviste genstanden sig tilsyneladende ikke at være den eftersøgte skat.Endelig må det ikke glemmes, at beslutningstagerne og eftersøgningsholdene ikkekunne være sikre på, at den eftersøgte komponent havde overlevet nedstyrtningen.251

Det må antages, at de har været åbne over for den mulighed, at den kunne være gåeti tusinde stykker eller på anden vis være blevet ødelagt.BBC overdriver undervandsoperationernes konﬁdentialitet. De blev gennemførti henhold til en aftale, der var opnået i en række dansk-amerikanske møder. H.H.Koch, formanden for den danske atomenergikommission, forstod udmærket, atbundundersøgelsen ikke var nogen større operation.Vi kan med andre ord vende tilbage til det tidligere svar i en noget udvidet form: Derer ikke nogen bombe, der var ikke nogen bombe, og amerikanerne ledte ikke efternogen bombe. De ledte efter marskalstaven. Ej heller var der nogen hele stykker afen primary eller en secondary eller en halesektion.Dette er måske stedet for en stille konstatering af, at udenrigsministerens erklæring i1987 om dykningerne, som vi omtalte i indledningen, var fuldstændig korrekt.Amerikanerne ledte altså efter en våbenkomponent, ikke en bombe, og næsten sikkertefter den ﬁssile kerne med uran 235 fra en secondary. De var sandsynligvis overhovedetikke sikre på, at den virkelig var faldet ned på bunden, eller i hvilken tilstand, eller omden i det hele taget stadigvæk eksisterede. Selv i koldt vand forvitrer uran 235. Hvisder har været noget at ﬁnde, fandt de det ikke i de sidste dage af august 1968.En sammenligning med eftersøgningen af en intakt bombe i Palomares to år tidligereleverer endnu et hårdt slag mod ideen om et kernevåben på havbunden i Bylot Sund.Det er åbenlyst, at undervandsoperationen i Thule havde en meget lavere prioritetend den heldigt gennemførte eftersøgning i Palomares.Dette udleder vi både af en analyse af diskussionerne i Washington og af de megetforskellige dimensioner, som de respektive undervandsundersøgelser havde. Enomfattende side track sonar scanning i Bylot Sund i 2003 udført af Danmarks ogGrønlands Geologiske Undersøgelse viste ingen tegn på vraggods fra ulykken, kunen gammel jernramme. Juvelerne var ikke i havet, men i arkiverne.

Rigsarkivetis the Danish National Archives. http://www.sa.dk/content/us/about_us/danish_national_archives.Atomenergikommissionenis the Danish Atomic Energy Commission (1955-1976).http://oldwww.sa.dk/brug_arkivet/rasaml/efter1848/energi/B1129.htm317 Collection. 1994. [A collection of documents released by DOE in September1994. Many of the documents were declassiﬁed in 1988. There are only minorvariations between the 317 Collection and the following 348 Collection].348 Collection. 2001. [An expanded version of the 317 Collection. These docu-ments were handed over to BBC journalist Gordon Corera by DOE in 2001in response to a FOIA request. A copy of this collection was sent to the Dan-ish government in January 2009 and subsequently distributed to members ofParliament and others]. [Document numbers in the text of the report refer tothe 348 Collection. A database of the collection, with excerpts, is available fordownload on www.diis.dk. The documents are available in pdf format on www.thulesagen.dk (Thulesagen.dk)].AEK 26/1 1968. Atomenergikommissionen, 26. januar 1968. Notat vedrørendemøde i atomenergikommissionens mødesal torsdag den 25. januar 1968 kl.9.30. [Minutes from meeting with Dr Walske in Copenhagen]. Copenhagen:Rigsarkivet, 1129 AEK, 1961-1971, journalsager 1966-1970, pk. 270.AEK 29/1 1968. Atomenergikommissionen, 29. januar 1968. Notat vedrørendemøde i atomenergikommissionens mødesal mandag den 29. januar 1968 kl.13.00. [Minutes from Commission meeting in Copenhagen]. Copenhagen:Rigsarkivet, 1129 AEK, 1961-1971, journalsager 1966-1970, pk. 271.AEK 18-19/3 1968. Atomenergikommissionen. Noter fra Pentagon-møde I, 18.marts, og II, 19. marts 1968 [Brief informal notes from Danish-U.S. Meetingin Washington]. Copenhagen: Rigsarkivet, 1129 AEK, 1961-1971, journalsager1966-1970, pk. 271.AEK 28/5 1968. Atomenergikommissionen. Møde med Carl Walske den 28/5-68[Hand-written minutes of meeting with Carl Walske in Copenhagen]. Copen-hagen: Rigsarkivet, 1129 AEK, 1961-1971, journalsager 1966-1970, pk. 271.AEK 18/7 1968. Atomenergikommissionen. Møde med general Glasser den 18/7-68[Hand-written minutes of meeting with General Glasser in Copenhagen]. Co-penhagen: Rigsarkivet, 1129 AEK, 1961-1971, journalsager 1966-1970, pk. 271.255

Albright, David et al. 1993. World inventory of plutonium and highly enricheduranium 1992, SIPRI, Stockholm: Oxford University Press.Albright, David et al. 1996. Plutonium and highly enriched uranium 1996. World in-ventories, capabilities and policies. SIPRI, Stockholm: Oxford University Press.BBC News 13/8 2000. Nuclear bomb ‘lost near Greenland’. 13 August. http://news.bbc.co.uk/2/hi/americas/878907.stmBBC News 14/8 2000. Denmark rejects Greenland nuke report. 14 August. http://news.bbc.co.uk/2/hi/europe/879836.stmBBC News. 2008. Mystery of lost US nuclear bomb. Article by Gordon Corera. 10November. http://news.bbc.co.uk/2/hi/europe/7720049.stmBBC Radio. 2008. Searching for a missing nuke. BBC Radio World Service, 11November. http://www.bbc.co.uk/worldservice/news/2008/11/081111_nu-clear_bomb.shtmlBBC Two. 2008. US ‘abandoned nuclear bomb’. BBC Two Newsnight, 11 Novem-ber. http://news.bbc.co.uk/2/hi/programmes/newsnight/7722204.stmBroken Arrow Aftermath. 1966. USAF Nuclear Safety, Vol. 52. September-Octo-ber: 2-6. [On Palomares; a sort of continuation of Broken Arrow Palomares].Excised version. http://www.dod.mil/pubs/foi/reading_room/134.pdfBroken Arrow Palomares. 1966. USAF Nuclear Safety, Volume 51? [No furtherbibliographic data]: 4-8, 29-37 [1-13 in the pdf ﬁle pagination] [Whole ﬁleis 289 pages and also contains diverse correspondence and telexes, some con-cerning Palomares]. Excised version. http://www.dod.mil/pubs/foi/reading_room/133.pdfBroken Arrow Thule. 1968. USAF Nuclear Safety, Classiﬁed Section, JUL/AUG/SEP, No. 3, Volume 60 (Part 1): 2-5 [17-20 in pdf ﬁle]. Excised version. http://www.dod.mil/pubs/foi/reading_room/133.pdfChu, Steven. 2009. Memorandum for Heads of Departmental Elements, From:Steven Chu, Subject: Freedom of Information Act. June 5. Washington, D.C:The Secretary of Energy. http://www.fas.org/sgp/othergov/doe/foia060509.pdfCrested Ice. 1970. Project Crested Ice: a joint Danish-American report on the crashnear Thule Air Base on 21 January 1968 of a B-52 bomber carrying nuclearweapons. Danish Atomic Energy Commission, Research Establishment Risø,Risø Report No. 213. [Reprint of USAF Nuclear Safety, AFRP 122-1 JAN/FEB/MAR 1970, No. 1, Volume 65 (Part 2) Special Edition, Project CrestedIce].Crested Ice SAC. 1969. Project Crested Ice: Thule nuclear accident, Vols. I-VI,SAC Historical Study #113 (Vol. I) with supporting documents (Vols. II-VI),256

History & Research Division, Headquarters Strategic Air Command, 23 April1969. [Originally classiﬁed secret. The study is still partially withheld. Amongthe supporting documents are the radiological surveys from Thule. Carl Walskesent these to H.H. Koch as enclosures to a letter of 15 April 1968, togetherwith a Sandia report (doc. 106917) on the atmospheric dispersion of plutoniumfrom the Thule crash (Walske-Koch 15/4 1968). The radiological surveys weresent once more to the Danish government in 1988 and declassiﬁed by arrange-ment with the State Department in 1994. The radiological surveys are available,for instance in Rigsarkivet, cf. Walske-Koch 15/4 1968, and at http://handle.dtic.mil/100.2/ADA283578]. [Vol. I is available in a sanitized version at theweb site of the National Security Archive in Washington, D.C.: http://www.gwu.edu/~nsarchiv/nukevault/ebb267/03.pdf. The weapons recovery chapter,‘Picking Up the Pieces’, is especially badly aﬀected by excisions.]Dahlgaard, Henning et al. 2001. Plutonium in the marine environment at Thule,NW-Greenland after a nuclear weapons accident. In Plutonium in the environ-ment, A. Kudo (Ed.). Elsevier.DOE. 1996. ‘Drawing back the curtain of secrecy’: restricted data declassiﬁcationdecisions, 1946 to the present (RDD-3). Washington, D.C.: U.S. Departmentof Energy, Oﬃce of Declassiﬁcation, January 1. https://www.osti.gov/opennet/forms.jsp?formurl=document/rdd-3/rdd-3.html#ZZ0Drell, Sidney & Bob Peurifoy. 1994. Technical Issues of a Nuclear Test Ban. An-nual Review of Nuclear Particle Science, 44: 285-327.DUPI. 1997. Grønland under den kolde krig: Dansk og amerikansk sikkerhed-spolitik 1945-68 [Separate summary: Greenland During the Cold War: Danishand American Security Policy 1945-68. Summary], 2 vols. Copenhagen: DanskUdenrigspolitisk Institut/Danish Institute of International Aﬀairs (DUPI).Eriksson, Mats. 2002. On weapons plutonium in the Arctic environment (Thule,Greenland). Roskilde, Denmark: Risø National Laboratory. http://www.thule-sundhed.dk/Webnodes/download/137Eriksson, Mats. 2005. Hot particles: what are they and do they have any environ-mental importance? IAEA – Marine Environment News, Vol. 3, No. 2, De-cember: 5.Eriksson, Mats et al. 2008. U, Pu, and Am nuclear signatures of the Thule hydrogenbomb debris, Environmental Science & Technology, 42 (13): 4717–4722.Final response. 1995. Final response to Danish questions on B-52 crash [by U.S.Government].FOTAB. 1968. Forbindelsesoﬃcer Thule Airbase [Danish Liaison Oﬃcer]. Co-penhagen: Rigsarkivet, 0301-030 Grønlands Kommando, Forbindelsesoﬃcer257

Thule Airbase 1954-1970. K.A. Sagsakter fortrolige, 1966-1968, K-10. [Afklas-siﬁceret efter redaktionens slutning].GEUS. 2003. Akustisk kortlægning af havbundssedimenterne i Bylot Sound, Thule,[Acoustic mapping of sea bottom sediments in Bylot Sound, Thule]. Rapport2003/103. Copenhagen: Danmarks og Grønlands Geologiske Undersøgelse[Geological Survey of Denmark and Greenland].Grilly, Julie Langham. 1995. Oral History of Julie Langham Grilly. Conducted Febru-ary 3, 1995. Washington, D.C.: DOE, Oﬃce of Human Radiation Experiments.Gregory, Shaun. 1990. The Hidden Cost of Deterrence: Nuclear Weapons Acci-dents, Brassey’s.H.H. Koch notat. 1968. Foreløbigt notat af 5. februar 1968 vedrørende spredtplutonium ved Thule. [Memo concerning dispersed plutonium]. Copenhagen:Rigsarkivet, UM 93.USA.8.c.HIAS. 1988. Telex fra Forsvarskommandoen til Forsvarsministeriet af 18. maj1988. B-52 bombeﬂyulykken ved Thule i januar 1968 [analyse fra Hærens In-geniør og ABC-skole af 16 timers video fra bundundersøgelserne ved Thule[analysis by the Danish Army School of Engineering and NBC Defence of 16hours of video from the sea bottom survey in Thule]]. Declassiﬁed and receivedby DIIS on 30 June 2009.IAEA. 2008. International peer review of the technical content of the projectproposal ‘Thule-2007 – Investigations of radioactive contamination on land’.Vienna: International Atomic Energy Agency. http://www.thulesundhed.dk/Webnodes/download/264J-P 12/8. 2000. Brintbomben ligger der endnu. [The H-bomb is still there]. Jyl-lands-Posten, 12. august. http://jp.dk/indland/article740753.eceJ-P 19/8. 2000 Niels Helveg fastholder forklaring om Thule. [Niels Helveg con-ﬁrms his explanation on Thule]. Jyllands-Posten, 19. august. http://jp.dk/ind-land/article733195.eceKristensen, Hans M. 2008. ‘Non c’è nessuna bomba atomica dispersa in Groen-landia’ [There was no missing nuclear weapon in Greenland]. Interview withHans M. Kristensen on the Italian channel Panorama.it, 12 November. http://blog.panorama.it/mondo/2008/11/12/non-ce-nessuna-bomba-atomica-disper-sa-in-gronlandia/Langham, Wright H. 1972. Trip Report on Foreign Travel (October 25-November15, 1971). March 1.Lind, O.C. et al. 2007. Characterization of U/Pu particles originating from the nu-clear weapon accidents at Palomares, Spain, 1966 and Thule, Greenland, 1968.Science of the Total Environment 376: 294–305.258

NATO. 1996. NATO handbook on the medical aspects of NBC defensive opera-tions. AMedP-6(B) Part I – Nuclear, Annex B, Hazards of nuclear weaponsaccidents. Washington, D.C. http://www.fas.org/nuke/guide/usa/doctrine/dod/fm8-9/1appb.htmNielsen, Sven P. & Per Roos. 2006. Thule-2003: Investigation of Radioactive Con-tamination. Risø-R Report, Risø-R-1549(EN), May. Risø National Laboratory.http://www.thulesundhed.dk/Webnodes/Ris%F8-R-1549EN/138Notits 25/1 1968. Notits af 25. januar 1968 fra P.J.IV om møde i Atomenergikom-missionen med den amerikanske forsvarsministers særlige rådgiver i atomen-ergispørgsmål, dr. Carl Walske.[Memo, Danish Ministry of Foreign Aﬀairs].Copenhagen: Rigsarkivet, UM 93.USA.8.c.Notits 5/2 1968. Notits af 5. februar 1968 om Thule-sagen fra udenrigsministeri-ets afdeling. P.J.IV. [Memo, Danish Ministry of Foreign Aﬀairs]. Copenhagen:Rigsarkivet, UM 93.USA.8.c.Notits 15/3 1968. Notits af 15. marts 1968 om redegørelse fra den svenske Försva-rets Forskningsanstalt om strålingsrisikoen i forbindelse med nedstyrtningenved Thule af amerikansk bombeﬂy, fra udenrigsministeriets afdeling P.J.IV.[Memo, Danish Ministry of Foreign Aﬀairs]. Copenhagen: Rigsarkivet, UM93.USA.8.c.Notits 18/7 1968. Notits af 18. juli 1968 om møde i Atomenergikommissionenom oprydningsarbejdet efter nedstyrtningsulykken ved Thule fra udenrigsmin-isteriets afdeling P.J.IV. [Memo, Danish Ministry of Foreign Aﬀairs]. Copen-hagen: Rigsarkivet, UM 93.USA.8.c.Obama, Barack. 2009. Memorandum for the heads of executive departments andagencies, Subject: Classiﬁed information and controlled unclassiﬁed informa-tion. May 27. Washington, D.C.: The White House.OTA. 1993. Dismantling the bomb and managing the nuclear materials. OTA-O-572. Washington, D.C.: U.S. Congress, Oﬃce of Technology Assessment,September. http://www.fas.org/ota/reports/9320.pdf.Risø. 2005. Thule-2003: Undersøgelse af radioaktiv forurening. DANCEA projektstøttet af Miljøstyrelsen. Status august 2005 [Thule 2003: Investigation intoradioactive contamination]. Risø. http://www.thulesundhed.dk/Webnodes/download/101Some Radiological Aspects. 1968. Some Radiological Aspects of the SAC B-52GBomber Crash at Thule Air Force Base, Greenland, [probably by W.H. Lang-ham], received in the AEK 15 April 1968. Copenhagen: Rigsarkivet, 1129Atomenergikommissionen (AEK), 1961-1971, journalsager 1966-1971, pk.269.259

Thulesagen.dk: Web site with the 348 Collection. [Apparently placed on the sitein 2006-2007. Both pdf versions and OCR scanned html versions of the docu-ments are available. The OCR scanned versions are, of course, not perfect, butstill a great help by making the pdf ﬁles (nearly) full text searchable. Try thissearch string in Google to see how it works: Seaborg site:www.thulesagen.dk]http://www.thulesagen.dk/viewpage.php?page_id=36.Thulesundhed.dk. Web portal with scientiﬁc articles and reports on plutoniumand uranium in the Thule environment. http://www.thulesundhed.dk/Web-nodes/Thule/Videnskabelige+rapporterVantine, Harry C. & Thomas R. Crites. 2002. Relevance of Nuclear WeaponsClean-up Experience to Dirty Bomb Response. Paper presented at AmericanNuclear Society, Sessions on Radiological Terrorism, 2002. Lawrence Liver-more National Laboratory. https://eed.llnl.gov/ans/2002/vantine/vantine_pa-per.phpWalske-Koch 5/4 1968. Letter from Carl Walske to Hans H. Koch. Copenhagen:Rigsarkivet, 1129 Atomenergikommissionen (AEK), 1961-1971, journalsager1966-1971, pk. 271.Walske-Koch 15/4 1968. Letter from Carl Walske to Hans H. Koch, [with 9 en-closures (1 missing) (radiological survey data) [these survey data are found inCrested Ice SAC 1969 as well]. [The missing enclosure is Sandia Corporation’sreport of 12 February 1968 on the atmospheric dispersal of contaminationfrom the Thule crash, which is available in the 317 and 348 collections as doc.106918. Incidentally, Sandia’s report had already been delivered once, by hand,in Copenhagen 13 February 1968 (doc. 106917)]. Copenhagen: Rigsarkivet,1129 Atomenergikommissionen (AEK), 1961-1971, journalsager 1966-1971,pk. 271Walske Letter. 1968. ‘The Walske Letter’: Memorandum from the Departmentof Defense Military Liaison Committee (Carl Walske) to the Atomic EnergyCommission (General Edward B. Giller), March 14. [Speciﬁes safety criteria fornuclear weapons. This entry is for information purposes only. The author hasnot seen the document].Aarkrogs dagbog. 1968. Dagbog udført af A[sker] Aarkrog under ophold påThulebasen. [Diary from Thule by Asker Aarkrog]. Copenhagen: Rigsarkivet,1916 Forskningscenter Risø [Risø National Laboratory], Direktionen: 1968-1969, Materiale vedr. B-52 ﬂystyrt i Grønland. Udskrifter af log mm., pk.108.

��Low Order ExplosionLow explosives change into gases by burning or combustion. These arecharacterized by deﬂagration (burning rapidly without generating a highpressure wave) and a lower reaction rate than high explosives. The overalleffect ranges from rapid combustion to a low-order detonation (generallyless than 2,000 meters per second). Since they burn through deﬂagrationrather than a detonation wave, they are usually a mixture, and are initi-ated by heat and require conﬁnement to create an explosion. Gun powder(black powder) is the only common example.DetonationAlso called an initiation sequence or a ﬁring train, this is the sequence ofevents which cascade from relatively low levels of energy to cause a chainreaction to initiate the ﬁnal explosive material or main charge. They can beeither low- or high-explosive trains. They involve a chemical reaction thatmoves through an explosive material at a velocity greater than the speedof sound in the material. A detonation is a chemical reaction given by anexplosive substance in which a shock wave is formed. High temperatureand pressure gradients are generated in the wave front, so that the chemi-cal reaction is initiated instantaneously. Detonation velocities lie in theapproximate range of 1,400 to 9,000 m/s or 5,000 to 30,000 ft/s.High Order ExplosionHigh explosives are capable of detonating and are used in military ord-nance, blasting and mining, etc. These have a very high rate of reaction, highpressure development, and the presence of a detonation wave that movesfaster than the speed of sound (Mach 1, or 331.46 meters per second, atsea level). ‘High Order Explosion’ also often means that, because the HEcarries all the oxident required for the complete combustion of the explo-sive material in a charge, there is, in fact, a complete oxidation or a HighOrder Explosion of all of the explosive material. Without conﬁnement, theyare compounds which are initiated by shock or heat and have high brisance(the shattering effect of an explosion). Examples include primary explosivessuch as nitroglycerin that can detonate with little stimulus, and secondaryexplosives such as dynamite (trinitrotoluene, TNT) that require a strongshock (from a detonator such as a blasting cap).

Sometimes the reservoir is called a T bottle in the documents. After the Thuleaccident, all four reservoirs were recovered near the impact point. Becausethe tritium in reservoirs decays, a reservoir has to be periodically replaced.This exchange is normally performed at the weapons storage and mainte-nance site. As a result, the reservoir is located outside the ‘physics package’(alternatively, the nuclear explosives package), i.e., the sealed portion includingthe primary/ﬁssion trigger and the secondary/thermonuclear stage. At theproper time for weapons arming, the deuterium-tritium (DT) gas moves viasmall-diameter tubing from the reservoir to the primary.The maybe somewhat exposed location of the reservoir outside the nuclearexplosives package and its relatively low weight appear to offer an explana-tion for why all the reservoirs broke loose from the nuclear package rightaway and were found close to the impact point, whereas some of the heavypieces of secondaries slid 2 miles or more on the ice, with an initial speed ofperhaps close to 300 meters per second.

��U.S. Air Force Fact SheetMARK 28 THERMONUCLEAR BOMBThe Mk-28 ‘hydrogen’ bomb, although ﬁrst produced in 1958, is still an ac-tive weapon. It was designed to be carried by various ﬁghter and bomberaircraft (F-100, F-104, F-105, B-47, B-52 and B-66). The ‘28’ warhead wasalso used in Hound Dog and Mace missiles, which have now been discon-tinued.The Mk-28 is capable of a ground or air burst and may be carriedinternally or externally, with a free-fall or parachute-retarded drop, depend-ing upon its conﬁguration.The Mk-28 employs the ‘Building Block’ principle, permitting various combi-nations of components:B28EX: Carried externally by F-100, F-105 and F-4; no parachute.B28RE: Carried externally; equipped with one 4-foot pilot chute and one28-foot ribbon chute.B28IN: Carried internally by B-52 and F-105; no parachute.B28RI: Carried internally; equipped with one 4-foot pilot parachute, one16.5-foot ribbon extraction chute, one 64-foot solid chute, and one30-inch stabilization chute.B28FI: Carried internally; equipped with one 4-foot pilot chute, one 16-foot chute and one 24-foot chute.