133. Telegram 77350 From the Department of State to the Mission to the North Atlantic Treaty Organization1
77350. Subject: TTBT/PNE Round II Negotiations: Letter to NAC. Disto. Geneva for Givan.
1. Request Mission prepare following letter for SYG Luns, with copies to NAC PermReps, via usual secret channels. Please advise Department of date letter circulated.
2. Begin text: This letter summarizes the second round of U.S.-Soviet negotiations on an agreement governing nuclear explosions for peaceful purposes (PNEs) in accordance with Article III of the Threshold Test Ban Treaty (TTBT). The first round of these negotiations, which [Page 443] took place in Moscow from October 7 until November 6, 1974 was summarized in letter to NAC dated 16 January 1975. The second round began in Moscow on 10 February 1975 and closed on March 22 for a working recess of about one month.
3. In Round II the U.S. maintained, as in Round I, its position that to be acceptable a TTBT/PNE agreement must satisfy the following criteria, which were explicitly accepted by the Soviets in Round II:
(A) PNEs must not provide weapon-related benefits otherwise precluded or limited by the TTBT.
(B) The fact that PNE activities are not contributing to such benefits must be adequately verifiable.
(C) The agreement must be consistent with existing treaty obligations, including the Limited Test Ban Treaty (LTBT).
4. The U.S. position on contained PNEs remained as in Round I, namely, that:
(A) In view of the greater uncertainty to be expected in verifying the yields of PNEs (relative to that expected for explosions at specified test sites) with national technical means, contained explosions should be limited to a maximum yield of 100 kilotons.
(B) It is also necessary to verify that the local circumstances are consistent with the stated peaceful purpose.
(C) The primary elements of yield verification for contained explosions are teleseismic measurements, information exchange and observer functions. The information exchange would include advance information on the purpose, date, time, depth, yield, coordinates, and the real geological and geophysical properties of the medium at and near the burst point, to include a description of the geological section, and of the basic physical properties of the lithologically distinct rock units present, such as: density, rock strength, seismic velocity, porosity, degree of water saturation and depth of water table. The statement of purpose would include a project plan, and a schedule of activities related to the event which would include:
(1) A full and clear description of the planned event;
(2) Details on the explosives emplacements;
(3) Planned times of the emplacements;
(4) Planned times of individual and group explosion;
(5) Depths of burial of the explosives;
(6) Relationship to nearby geological features and other relevant features which either influence the objectives of the explosion or constrain the yields, depths or other characteristics.
(D) After the explosions, actual yields and results would be exchanged.
[Page 444]5. The U.S. put forth its position on excavation PNEs as follows:
(A) Limit in the yield of a salvo of 500 kilotons.
(B) An unspecified limit on the yield of individual excavation explosions to be agreed between the sides. The U.S. delegation did not propose a specific number for this limit.
(C) A fission yield limit on each explosive.
(D) A specified minimum depth of burial.
(E) Provision for information exchange and observer functions in order to augment national technical means of verification of all of the above limits. Information exchange would be the same as listed in para 4 (C).
6. By the end of Round II the following Soviet proposals had been made:
(A) A yield limit of 150 kt for single contained events. The Soviets proposed that groups of contained explosions be allowed with aggregate yields larger than the agreed upper limit on single contained explosions if the group array is so designed that each individual explosion in the group can be distinguished and its yield measured by practical verification arrangements. The U.S. agreed to consider this proposal.
(B) A limit of 500 kt for individual excavation explosions, with a small number to be allowed having yields above the limit. No limit on the yield of excavation salvos, although there were indications of flexibility on this point.
(C) The Soviets presented ideas on information exchange, based on the following yield regions:
(1) Yield region one: individual and aggregate yields up to 50–70 kt. Pre-shot information to be provided on date, time, location, aggregate yield and purpose, post shot information or actual yields and results.
(2) Yield region two: Individual and aggregate yields from 50–70 kt to 150 kt. In addition to information exchange for yield region one, information provided in yield region two would include depth, and geological and geophysical data.
(3) Yield region three: Individual yields less than 150 kt, aggregate yields greater than 150 kt. In addition to preceding information, the following additional information would be exchanged: number of explosives, yield of each, and relative positions in space and time.
(4) Yield region four: Aggregate yields greater than 150 kt and at least one individual yield greater than 150 kt. Additional data exchanged for yield region four would include data on possible uncertainty in actual yields.
[Page 445](D) Indicated willingness to accept the U.S. proposals on limiting fission yield and depth of burial, but have not yet indicated what verification provisions would be acceptable.
(E) In contrast to their attitude toward observers in Round I, the Soviets now appear willing to accept observers for at least some PNE events provided that this can be described in a framework of cooperation.
7. The Soviets placed less stress on PNE cooperation than in Round I. The U.S. said that we do not exclude cooperation in principle; however necessary yield limitations and verification provisions must be worked out before proceeding to discuss cooperation.
8. Both sides stated that any PNE activities must take place in compliance with existing treaties, including the LTBT. End text.
9. U.S. Rep at NATO disarmament experts meeting may draw on foregoing in handling agenda item on test ban issues.
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Summary: The Department transmitted the text of a letter to NATO Secretary-General Luns that summarized the second round of PNE negotiations in Moscow.
Source: National Archives, RG 59, Central Foreign Policy File, D750118–0051. Secret; Priority. Drafted by Shea; cleared by Elliott, Molander, Kelly, Davies, Buchheim, Robert Einhorn (ACDA/IR), Edward Ifft (PM/DCA), G. Harlow (OSD), CIA, Lawrence Finch (INR), Roland Kuchel (S/S), and R. Duff (ERDA). Repeated Priority for information to the Mission in Geneva.
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