73. Aide-Mémoire From the Department of State to the Soviet Embassy1

In its note of March sixth, requesting further clarification of the Kiwi reactor safety experiment, the Soviet Government apparently misinterprets the position taken by the United States Government in its Aide-Mémoire of January 26, 1965.2

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The position of the United States Government is that the Kiwi experiment did not constitute a “nuclear explosion” within the meaning of the Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water. The experiment was a reactor safety test and its technical characteristics are readily distinguishable from a nuclear explosion. Reactors are legitimately present in all parts of the world; accidents in which they burn up or experiments designed to simulate such accidents have never been considered to be nuclear explosions, and consequently are not within the scope of the Treaty.

As a continuation of the discussions in these scientific areas held at the Conference on Peaceful Uses of Atomic Energy last September in Geneva, detailed descriptions and analyses of the Kiwi experiment will be made available to the world scientific community at the International Symposium on Fission Product Release and Transport Under Accident Conditions, at the Oak Ridge Laboratory during the first week of April. The Soviet Union has been invited to send representatives to attend and participate in that meeting and thus will soon have an opportunity to obtain further information concerning that experiment.

  1. Source: Department of State,S/S-I Files: Lot 79 D 246, Miscellaneous Microfilm Files, U.S./U.S.S.R. Conversations. Confidential. A cover memorandum of conversation by Thompson (S/AL), March 30, states that he asked Soviet Ambassador Dobrynin to come to the Department of State to give him the aide-mémoire. Dobrynin said he would transmit it to his government, but he made no comment on it.
  2. Document 67.