[Page 486]

202. Memorandum From Secretary of Energy Schlesinger to President Carter 1

SUBJECT

  • CONTINUED DISCUSSION OF A ZERO-YIELD CTB

Let me continue our discussion, started on the trip from Knoxville,2 regarding permitted experiments under the CTB by pursuing the points developed below.

1. Over many years the underlying thrust in weapons design has been to compensate for volumetric constraints and throw-weight limitations in the U.S. strategic program by developing highly compact, highly sophisticated weapons. Such high sophistication, as in other cases, results in some degree of technical risk. [7 lines not declassified]

2. Why would previously tested and certified weapons need to be retested? In the continued non-nuclear testing of weapons components, it turns out with some regularity that individual components fail or degrade. Even acceptable components may become unavailable as manufacturers shift product lines or go out of business. Materials are altered slightly or may (as with beryllium) be subject to more stringent regulation. The consequence is that new components or different materials have to be integrated into previously deployed weapons designs. Developing weapons remains to a considerable extent an art rather than a science. Weapons designs which seem appropriate, based on computer models, fail to work as predicted when actually tested.

[1 paragraph (16 lines) not declassified]

3. Readiness of material and men is of paramount concern to the military services. For this reason everything from radars to engines to missiles are regularly exercised to demonstrate that they will remain operationally ready. For there to be doubt about nuclear weapons reliability is vastly distressing to the Services. The notion that nuclear weapons might degrade over the years, and have attached to them [Page 487]lower confidence in reliability is disturbing both in military and political terms.

4. Even though we can detect nuclear detonations in hard rock down [less than 1 line not declassified] as a practical matter today [1 line not declassified] This is true if the Soviets make no effort to muffle or decouple weapons tests. The reasons are, first, that the Soviets can test in lower coupling media than hard rock. Second, for true verification we must be able, not only to detect seismic disturbances, but to identify such disturbances as nuclear detonations.

With an improved verification capability (a network of seismic arrays or stations located within the Soviet Union), [1 line not declassified] Even improved verification capability, however, creates problems. As our ability to detect improves, the number of ambiguous events will increase. Indeed, there will be several hundred such ambiguous events each year causing both (possibly undue) military alarm, but certainly political problems.

5. Aside from the technical and security aspect of a zero-yield test ban, the interactions between the non-verifiability of the prospective treaty and the potential non-certifiability of the stockpile will inevitably stir deep Congressional concern—in an atmosphere already stirred by other matters. The Administration has steadily pledged to sign no arms control agreement that cannot be adequately verified, though it has not in the case of the CTB yet stated what threshold is required for adequate verification. Recently, the Senate requested Mr. Warnke to address these concerns in assessing the verifiability of a CTB.3 Given basic suspicion and the strained relations with the Soviet Union, it will be difficult to persuade the Senate to trust the Soviets to comply with the Treaty in [1 line not declassified]

One cannot, of course, decouple the verification issue from the permitted experiments issue. Thus, the prospect that over time the DoE would be unable to certify stockpile reliability will vastly reinforce that concern. [2½ lines not declassified] We, by contrast, would most assuredly not test, and thereby be forced to absorb whatever degradation in reliability occurs because of the unknowns. It will be pointed out that there is an undoubted asym[Page 488]metry between ourselves and the Soviets in that they suffer less from throw-weight limitations, volumetric constraints, and the inherent sophistication that applies to our weapons.

When the partial test ban agreement was signed and approved in 1963, it could be stated that the burden of the agreement fell equally on both sides and the U.S. security position was improved. Given the problems of verification and certification—and the presumed asymmetry between ourselves and the Soviets—that conclusion cannot be readily drawn in the case of the zero-yield test ban. As a result Congressional resistance will be formidable and the arguments sharp. The Chiefs are already on record as opposing such a ban. The laboratories and DoE personnel will be obliged to elucidate the consequences for certification under such a ban. Leaving aside the military questions, the political consequences could hardly be worse.

6. Since (a) some testing will be required to maintain confidence in both weapons reliability and safety, and (b) very low or zero thresholds [less than 1 line not declassified] even under optimistic assumptions about Soviet agreement to on-site seismic detection, I urge you to consider the following course of action.

This alternative approach serves the national security interests of the United States and its allies, takes a reasonable step toward legitimate arms control (no new weapons development), and avoids a protracted and uncertain Congressional debate. The alternative is to indicate American willingness to accept drastic reduction in the presently proposed threshold test ban from 150 KT [less than 1 line not declassified] Such a level is consistent with our existing verification capabilities. Moreover, we should also indicate that, if the Soviets are prepared to allow a network of internal seismic stations or arrays, we could reduce that threshold [less than 1 line not declassified]

Such an approach would be consistent with both certification requirements and our present verification capabilities—and would also put pressure on the Soviets to allow improvements in those verification capabilities. A prudent approach of this sort on arms control would better serve the interests of the nation and would also have a higher chance of success.

  1. Source: Carter Library, National Security Affairs, Brzezinski Material, Subject File, Box 6, Comprehensive Test Ban (CTB), 1–12/78. Secret; Restricted Data. In the upper right-hand corner of the memorandum, Carter wrote “Zbig—You & Jim set up a briefing with a lab director & me. a) I don’t know how device works & b) what Soviet position is on this issue. J.”
  2. No record of this conversation has been found. According to the President’s Daily Diary, Carter was in Tennessee on May 22 to speak to the Tennessee Valley Authority and to address a group of scientists at the Oak Ridge National Laboratory. (Carter Library, Presidential Materials)
  3. Not found.