293. National Security Council Under Secretaries Committee Decision Memorandum 221 2


  • The Deputy Secretary of Defense
  • The Assistant to the President for National Security Affairs
  • The Chairman of the Joint Chiefs of Staff
  • The Chairman, Atomic Energy Commission
  • The Director U.S. Arms Control & Disarmament Agency
  • The Science Advisor to the President
  • The Director, United States Information Agency
  • Assistant Director, Bureau of the Budget, Mr. Schlesinger


  • Peaceful Nuclear Explosions and the Limited Test Ban Treaty


  • NSCU/SM 43

The Committee discussed at length the basic issues and underlying differences of view reflected in the Interagency Study Group report. The Committee endorsed the conclusion reached by the Study Group that if the United States wished to fully develop and utilize peaceful nuclear excavation explosions, the Limited Test Ban Treaty would have to be modified. The Committee further agreed that amendment of the Treaty would probably be the best long-term solution. Leaving the timing question open, the Committee agreed that the United States should develop as fully as possible its preferred long-term solution, and its technical rationale.

The Committee thereupon decided that:

a. The AEC will continue the development of the data necessary to evaluate the utility of various objective [Page 2]radioactivity criteria in interim and long-term approaches. (Initial results of the AEC studies to be available by January 15, 1970.)

b. The Interagency Study Group will: (1) examine the initial results of the AEC studies with a view to determining whether acceptable objective criteria are feasible in interim or long-term approaches, and (2) prepare further recommendations for consideration by the Under Secretaries Committee regarding the amendment approach and interim measures (Tentative deadline established of March 1, 1970.)

c. Bilateral technical talks with the USSR on the technology of peaceful nuclear explosions should be resumed at an early date after appropriate consultation with our Allies. The next round of technical talks should take place within the coming months.

It was noted that an early establishment of the “de minimis” criterion for radioactive debris would be useful, despite the essentially political nature of such standards. The “de minimis” criterion could be used as an interim, internal government-wide understanding of what would be permissible under the Limited Test Ban Treaty, and might find utility in interim public interpretation of the LTBT by the U.S. It was further argued by the Legal Adviser that it would be most difficult to sustain a “de minimis” legal case, in view of the Limited Test Ban Treaty’s nature, explicit language and negotiating history, although a rational for a “de minimis” interpretation was also described.

With regard to pending excavation shots related to the new sea-level Atlantic-Pacific Canal, the AEC stated that by conducting only two more key experiments, one of which would be Project Sturtevant, it could resolve the major technical uncertainties relating to Route 25, the only potentially viable route outside of Panama.

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It was noted that in an atmosphere of heightened public concern over activities that affect the environment, even these two PLOWSHARE shots might draw down the already limited level of public tolerance for the entire testing program—both weapons and peaceful. Seeking a Treaty amendment at this time would undoubtedly encounter strong pressure to link this issue with a comprehensive test ban treaty, and with progress by the nuclear powers in other disarmament areas such as SALT and the NPT.

The Committee therefore agreed to ask the Interagency Study Group to address promptly the question of the relative importance of the excavation part of the development of peaceful nuclear explosions, against this background of political risks, both domestic and international.

The Committee agreed to defer action on the AEC’s proposed project Sturtevant.

Arthur A. Hartman
Staff Director
  1. Source: Washington National Records Center, OSD Files: FRC 330–75–89, A–400.112 (Sep–Dec) 1969. Confidential. Prepared by Arthur Hartman.
  2. The memorandum is a record of the decisions reached at the October 14 NSC Under Secretaries Committee meeting, noting that, if the United States intended to continue with the Plowshare program, the LTBT needed to be modified.