Foreign Relations of the United States, 1969–1976, Volume E–14, Part 2, Documents on Arms Control and Nonproliferation, 1973–1976

161. National Security Decision Memorandum 304¹

Washington, September 8, 1975.

TO

• The Secretary of Defense
• The Deputy Secretary of State
• The Director, U.S. Arms Control and Disarmament Agency
• The Administrator, Energy Research and Development Administration

SUBJECT

• Instructions for the U.S. Delegation to the PNE Negotiations, Moscow, September 5, 1975

The following instructions have been approved for the negotiations on underground nuclear explosions for peaceful purposes (PNEs) which will resume in Moscow on September 5, 1975. These instructions supplement those contained in NSDM 297.

1. The Delegation should state that the U.S. prefers a 150 KT limit on all individual excavation PNEs and, in this context, would be willing to accept a one megaton limit on the aggregate yield of all PNE salvos. The Delegation should cite the following factors as contributing to this preference:

(a) There would be no need to distinguish between excavation and contained PNEs;

(b) The necessity for stringent verification provisions for excavation PNEs would be lessened; in particular, there would be no need for a fission yield restriction and its attendant melt sample collection;

(c) The public and international acceptance of both the Threshold Test Ban Treaty (TTBT) and the PNE agreement would be enhanced if all individual PNEs were subject to the TTBT yield restriction.

2. For PNE events with yields above 100 KT, observers should be permitted as needed at the discretion of the side verifying the explosion and observers should be permitted for all PNE groups with aggregate yields above 150 KT.

3. To augment verification of individual PNE yields, the Delegation should propose the use of SLIFERs for all PNE groups with aggregate yields above 150 KT.

4. The Delegation should continue to reiterate our position that all PNEs must be fully consistent with existing treaty obligations, including the Limited Test Ban Treaty (LTBT). In addition, it should state that U.S. studies indicate that it does not appear to be possible to carry out major PNE excavation projects without violating the LTBT. In this regard, the Delegation should avoid technical discussions of such matters as differences in interpretation of the LTBT or de minimus radiation standards.

5. The Delegation is authorized at an appropriate time upon approval by Washington to table on an ad referendum basis the draft PNE treaty prepared by the Verification Panel Working Group.

Henry A. Kissinger

1. Summary: Kissinger transmitted the approved instructions for the U.S. delegation to the fourth round of the PNE negotiations in Moscow.

   Source: Ford Library, National Security Council, Institutional Files—NSDMs, Box 61, NSDM 304—Instructions for the U.S. Delegation to the PNE Negotiations, Moscow, 9/5/75. Secret. Copies were sent to Brown and Colby. NSDM 297 is Document 150. The Department transmitted the instructions in telegram 214009 to Moscow, September 9. (National Archives, RG 59, Central Foreign Policy File, D750311–1129) The fourth round of PNE negotiations opened on September 5 and concluded on October 31.