Memo to Chairman Seaborg, Et Al, Subject: Underwater Search for Weapon Debris at Thule, Greenland (Attch: Letter to W L Hancock, Subject: Results of Study to Determine Sea Floor Search Area)

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Mtcroft of tame wvuofmhft Albuquerque Operations Office Albuquerque, Nev Mexico 87115 Re: Results of Study to Determine Sea Floor Search Area for On April 4, 1968, AEC/ALO requested Sandia Corporation to assist in defining an undervater search aria off the coast of Thule AFB, Greenland. A missing weapon part is presumed to be located in the area as the result of a recent B52 aircraft crash. This letter presents the res.ults of theoretical uolervater trajectory studies performed by Division 9324. Several assumptions were necessary in regard to the B52 flight character istics at the time of impact (Foint Zero). These assumptions are as Flight Path Angle Left wing down with aircraft in a gradual left turn Assumed water conditions: Physical characteristics of the missing objetts Spherical Radius of Ends: Cross Sectional Area

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Hydrodynamic characteristics of object: /• Drag Coefficient (end on): 0.6 Drag Coefficient (side on): 1.0 Note: The drag coefficients include cavitation effects. A study to determine the velocity degradation, assuming the object penetrated two feet of ice, showed a loss of approximately 50 fps might be expected (Foint 1). This effect, plus any effect on velocity due to contact with other debris, is adequately covered in the variations of impact conditions The attached chart shows the results of several trajectories and defines a suggested search area with probabilities. The angular limits were determined from the pattern of debris found on the surface of the ice.

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Engelst oversaefctelse af henvendelsen til USA Documents recently declassified and released by the U.S. De partment of Energy concerning the crash of a B—52 at Thule fiFB in 1968 and the subsequent cleanup operation have given rise to a number Of questions. We would greatly appreciate your assistance in the clarification of these questions. Throughout the years there has been a good and positive cooperation between Danish and American authorities in this case. This would undoubtedly also be the case with regard to fhp- enclosed questions, which have arisen due to apparent discrepancies between our previous knowledge and the recently ;i With a view to a deepening or clarification of the questions j; listed hereunder, the Danish authorities are of course wdl— !, ling and ready to assist, if need be, in a meeting. 1. in order to make our records of the 1968 accident as com— jj plete as possible, we kindly ask that the information deleted i from the 317 documents that had been released earlier on - together with a small number of documents that had been with- ; held in toto from, the batch of Doe documents (doc. nr. 0107048, 0106961, 0106965, 0107004, 0104810) - be provided or < explained to Danish authorities — if need be, pn a privileged !; 2. We would like to request a confirmation of the fact that the four bombs on board of the crashed aircraft have, essen tially in their entirety, been found and recovered.3 3. The released documents indicate that U, S. authorities searched in vain for a "missing object" at the crash site in August, 1968. Would it be possible to make publicly avail able information on this object? Xn case this object should be situated on the bottom of the sea, we would like to know about the environmental risks this object poses today on the bottom of the sea. In this respect, reference is made to the ^ letter from. Sandia Corp, to the U.S. Atomic Energy Commission i also like to ask for information about to what extent parts of the wreck and remnants of the bomba still can be found on the bottom of the sea. j

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in t±is light of thisr and takitig into consideration environ mental and health risks, we would like to request that the 1 American authorities ensure that everything which today is j; technically feasible will be undertaken in order to remove Ji any remaining radioactive parts of the wreck that still might ii be found on the bottom of the sea. In this context, we should j; like to solicit your authorities' assessment of whether the |i environmental and health risks entailed by the removal of these remnants might toe out of proportion to the environ— Ji mental effects experienced today. ji j; 4, Proceeding from, the released information that 6 kg of plutonium were involved in the crash, we would appreciate being provided with more detailed facts about both the nature i, and quantity of those substances released at the crash which l involve health or environmental risks - and particularly ra— ; dioactive substances (radionuclides). We would furthermore . i ■nre to know if there was a chance of these substances com bining with each other (chemically) either before or in con- !; nection with the plane crash. ji 5. We would very much appreciate your authorities# assess— j meat of whether the following account of the quantities of plutonium involved in the crash can be confirmed. j Proposal for an account of the plutonium: 1 Plutonium on bomb and aircraft rem nants brought to the USA: Plutonium on the surface of the ice: 3.15 ± 0,63 kg Plutonium bound in the ice: 0.35 ± 0,09 kg Plutonium spread by the wind: unknown The quantity of plutonium on the bottom of the sea has been measured to be 0.5 ± 0.1 kg. It is estimated that this plu— j! toaium contains all the above listed quantity of plutonium bound in the ice, and about 5% of the above listed quantity of plutonium on the surface of the ice, which had not been removed. In this context, we would appreciate being informed i. on the quantity of plutonium found in that snow and ice which j; was brought to the USA, In this regard, we should also like to inquire as to the limits and uncertainties connected to the abovementioned account, particularly as to whether it is possible today to estimate the quantity of plutonium that was spread by the

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Xn this context^ we should finally like to know whether it will be possible to famish a corresponding account for other j; radioactive substances involved (radionuclides). 6. We kindly ask that information on health assessments / examinations (including urine analyses for plutonium) of American personnel participating in the cleanup operation •; after the incident be provided. i We would also like to know whether there are or have been brought to court any lawsuits by American personnel claiming j liability for health injuries suffered in the cleanup oper- ii 7. According to your opinion, would it be possible to draw a parallel to the Ealcsoares, Spain, plane crash of 1966? Have damages to the health ox those participating in the cleanup operation or to the health of the local population been esta- j. 8. We kindly request being informed about to what extent t your authorities informed the representatives ofDenmark, ; already in 1968, about the exact quantity of plutonium i; carried by the four bombs. j9. We should, also like to ask to what extent your records \. confirm that representatives of the Danishauthoritieshave, • at the occasion of an August, 1988 meeting in Washington, ji been informed that it was impossible to provide information about the quantity of plutonium carried by the four nuclear j; weapons, and that it was impossible as well to draw up an j! account of the plutonium involved, since the quantity of plu- jj toni-um contained by those parts of the wreck and those rem— |; pants of the bombs which had been brought back to the USA had j; not been measured. |: Reference is made to the meeting which took place at Oak 23rd, 1988, between representatives of the Danish National Board of Health, RiS0 National Laboratory and others, and j. representatives of the U.S. Department of State, OSAF Head quarters, the U-S. Department of Energy, Oak Ridge Associated Universities and others. [