APPENDIX "A" BACKGROUND AND DISCUSSION 1. It is clear that with the entrance of nuclear weapons ‘ into the realm of megaton yields, new concepts of civilian defense must be formulated which will prepare civilian defense organizations for the destruction which would follow the detonation of such weapons over any portion of the United States. That this problem was recognized both by the AEC and by the Federal Civil Defense Administration is demonstrated in part by exchange of correspondence between the Federal Civil Defense Administrator and the Chairman of the AEC Appendices "B" and "C",. As requested by the Civil Defense Administrator, a "sanitized" version of the motion picture on Operation IVY has been prepared for showing before the group of mayors who will be attending the Mayors! Conference sponsored by the White House on December 14 and 15, DOE ‘ARCHIVES 2. The film a deleted version of the film "Operation Ivy", shows certain of the footage pertaining the Mike Shot of Operation IVY. All information which would give any indication as to the nature of the thermonuclear reaction, including identity of reactants, or the manner in which the reaction is brought about, has been deleted from the film leaving only the clear indication that the detonation was that of a thermonuclear device. While all specific mention of the yield of IVY Mike has been deleted from the film, sufficient information remains to permit calculation of the yield by a technically qualified person. This information has been allowed to remain in the modified version since to remove it would destroy the usefulness of the film. We do not feel that declassification of the yield of the MNixe device, Operation IVY, will adversely affect the 2