Foreign Relations of the United States, 1964–1968, Volume XI, Arms Control and Disarmament

251. Memorandum From the Director of the Arms Control and Disarmament Agency (Foster) to the Members of the Committee of Principals¹

Washington, July 2, 1968.

SUBJECT

• Cutoff of the Production of Fissionable Material for Weapon Purposes (U)

For several years the United States has been proposing in Geneva that the nuclear-weapons powers agree to halt the production of fissionable material for nuclear weapons. Since agreement on this proposal would clearly be in the U.S. net interest, we expect to propose it again at the forthcoming ENDC session this summer. The purpose of this memorandum is to propose updating one aspect of the verification arrangements for a cutoff treaty.

The other aspects of the U.S. position on this measure would remain as we have previously described them in Geneva. The plants engaged in production of enriched uranium or plutonium for use in nuclear weapons would either be shut down or their product would be utilized for purposes other than nuclear weapons. Each country would provide a list of all its nuclear facilities to the International Atomic Energy Agency (IAEA) and permit the IAEA to apply safeguards to ascertain that none of the produced fissionable material was being used for nuclear weapons. This would involve a major opening up of the Soviet nuclear energy program to international inspection.

When the United States described this proposal to the ENDC four years ago, we dealt with the possibility of undeclared production facilities by stating, “There would be agreed rights to conduct a limited number of inspections of suspected undeclared facilities on an adversary basis.”² In the light of our current unilateral capabilities in this field, I recommend that we withdraw this 1964 formulation, and rely instead on our unilateral capabilities to verify that other parties to the treaty are not operating significant undeclared nuclear material production facilities. My reasons for this recommendation are as follows:

1. The U.S. has high confidence that it has identified all current Soviet fissionable material production facilities which are capable of making a significant addition to the already large existing Soviet weapons stockpile.

2. [3 lines of source text not declassified]

3. [6 lines of source text not declassified]

4. Such elimination would remove a potentially troublesome discrepancy between the verification arrangements we would be willing to accept for a cutoff and those we have asked other countries to accept under the non-proliferation treaty. It is difficult to justify treaty rights to search for undeclared plants in a country which already has large stockpiles of fissionable materials, when the NPT does not set forth such rights for nations in which a small clandestine plant might be significant.

A more detailed discussion of the proposed modification of verification arrangements will be found at Tab A.

The United States initially proposed the cutoff in 1956³ after determining that such a measure would be in our net interest, and has reaffirmed this proposal on frequent occasions since that time. The relevant factors have recently been reviewed to determine whether that conclusion still obtains, and we have found that it does. The results of these studies are summarized at Tab B.

Accordingly, I recommend for your consideration that when we next propose the cutoff, we authorize the U.S. Delegation to describe the verification arrangements as similar to those of the non-proliferation treaty.

William C. Foster

Tab A⁴

Verification of a Cutoff of the Production of Fissionable Material for Weapon Purposes

The proposed modification in the U.S. position relates only to verification for undeclared plants. No change is proposed in the procedures the U.S. has previously set forth for verification with respect to declared plants. Nevertheless, the latter procedures are also summarized below to facilitate evaluation of the overall verification requirements.

A. Verification for Declared Production Facilities

The United States has proposed that the IAEA would apply safeguards in order to verify compliance with the obligations of the cutoff treaty. These safeguards would be similar to those applied under the non-proliferation treaty. The IAEA would safeguard not only nuclear reactors and uranium enrichment facilities, but also the fissionable material in every other peaceful nuclear facility in each country, in order to ascertain that no fissionable materials produced was being used for nuclear weapons purposes.

While the IAEA has not yet developed detailed procedures for safeguarding either uranium enrichment facilities or shutdown reactors, U.S. and U.K. studies have been made which can provide a basis for IAEA safeguards techniques for such plants. These techniques would be effective in detecting any significant Soviet diversion of fissionable material to weapons use.

On December 2, 1967, President Johnson offered to accept IAEA safeguards on all U.S. nuclear facilities, except those directly related to national security, when NPT safeguards go into effect.⁵

During the last session of the ENDC, several speakers urged the Soviet Union to accept IAEA safeguards on its peaceful nuclear programs. The Soviet delegate replied that such acceptance would not be relevant to the proliferation problem. While the U.S.S.R. has always resisted proposals for inspection on its own territory, the Soviets may find it difficult to explain why they are unwilling to accept relevant inspection for the cutoff proposal when the inspection is essentially the same as the IAEA safeguards which the U.S.S.R. has urged other states to accept under the NPT.

B. Verification for Undeclared Production of Fissionable Material

To verify that other parties to the treaty are not operating significant undeclared nuclear material production facilities, each party would rely on unilateral capabilities. [7-½ lines of source text not declassified]

Since the Soviets would realize that any significant violation would run a very high risk of detection, they can be expected to refrain from violations as long as they want the treaty to continue in force. If the Soviets wanted to terminate the treaty, they probably would find it preferable to do so by use of a treaty withdrawal clause, rather than by risking the onus of being caught in a violation.

An early test of Soviet good-faith compliance with the treaty would be their initial declaration listing their nuclear facilities. If this initial declaration is complete, and coincides with U.S. present highly reliable information on this subject, and the IAEA is permitted to safeguard freely all such Soviet nuclear facilities, it would seem quite unlikely that the Soviets would then attempt to build a new series of clandestine nuclear plants which involve no shipments to or from any of their declared, inspected facilities. If they did build such plants which would add significantly to their already large stockpile, the U.S. would have a very high probability of detecting such a violation.

[1 paragraph (14 lines of source text) not declassified]

A Soviet refusal to permit such a non-intrusive inspection would provide a basis for the U.S. to explain its withdrawal publicly if withdrawal became necessary. The Soviet refusal would be assessed by other states in the light of the U.S.S.R. having already accepted extensive inspection of its nuclear facilities.

Tab B⁶

SUMMARY OF CONCLUSIONS ON THE IMPACT ON U.S. INTERESTS OF A CUTOFF OF PRODUCTION OF FISSIONABLE MATERIALS FOR WEAPONS USES

The U.S. has proposed many times at the ENDC that the nuclear-weapon states halt all production of fissionable material for use in nuclear weapons, and that the U.S. and U.S.S.R. transfer from their weapons stockpiles to peaceful uses agreed amounts of uranium-235 and plutonium. We have said that the U.S. would so transfer 60,000 kg of uranium-235 if the U.S.S.R. would transfer 40,000 kg. We have suggested that this transferred uranium could be obtained by demonstrated destruction of nuclear weapons, and that we would transfer to peaceful uses the associated plutonium from these weapons in amounts to be negotiated with the U.S.S.R. in advance. This combined proposal will be referred to below as the “cutoff-transfer” proposal.

A. Impact on U.S. Strategic Posture

1. U.S. Military Requirements

The U.S. has recently concluded that our military requirements for plutonium can be met by operation of four production reactors at Richland. We have already shut down five plutonium production reactors at this site. Presently planned nuclear weapons requirements can be met from the uranium-235 and plutonium on hand. (This includes weapons in stockpile awaiting retirement and materials in the pipeline.) Reactor development and research are absorbing most of the current plutonium production at Richland. A small amount of plutonium metal is being stockpiled to meet contingency plans. (Three reactors at Savannah River are being used principally for production of tritium. Two similar reactors there have been shut down.)

Based on current plans, U.S. weapons requirements for the mid-1970’s can be met from fissionable materials on hand now. Even with a transfer of 60,000 kg of uranium and agreed amounts of associated plutonium from destroyed weapons to peaceful uses, all strategic U.S. military requirements for the near future can be met from existing stocks.

2. Soviet Military Requirements

It appears that the Soviets could meet their priority strategic requirements from existing stocks, even with a transfer of [1-½ lines of source text not declassified] from destroyed weapons to peaceful uses. However, they would not have enough fissionable material to MIRV their ICBMs and deploy an extensive ABM system.

3. Future Stockpile Comparisons

Recent studies have shown that the earlier a cutoff-transfer measure is implemented, the more it would be to the advantage of the U.S. Such an agreement would be to our advantage now and would remain so until about 1976. Following 1976, the proposed measures would not present a significant military advantage to either country. By that time, both the U.S.S.R. and the U.S. would have accumulated such large stockpiles of fissionable materials that any cutoff of production for weapons uses would be of little military significance.

[1 paragraph (10 lines of source text) not declassified]

A cutoff in 1968 to 1970 would slow down the accumulation of fissionable materials by both countries but would be more advantageous to the U.S. A cutoff in 1972 or later would have only a small effect on the accumulation of that amount of fissionable materials calculated to be necessary for both U.S. and U.S.S.R. top priority and second priority military requirements. A cutoff in 1976 or after would appear to have no direct military effect, because the availability of fissionable materials for military uses will be more than any predicted requirements can utilize.

4. Miscellaneous Aspects

When the U.S. first offered in September 1965 to obtain the 60,000 kg of uranium-235 for transfer from demonstrated destruction of nuclear weapons, it was determined that this could be done [2-½ lines of source text not declassified].

Tritium was dealt with in the U.S. cutoff-transfer position paper of February 15, 1966, along the lines outlined below. There have been no developments since then which call for changing this position.

Since tritium is not a fissionable material, it has not been covered in our past cutoff proposals, and we do not plan to initiate any discussion of tritium. (Of course, nuclear reactors, including tritium production reactors, would be subject to IAEA safeguards under a cutoff agreement.) If the U.S.S.R. should urge limitation of tritium production under the cutoff, however, the U.S. delegation has the following contingency guidance:

If progress in negotiations warrants it, the Delegation may request approval to discuss tritium production limitations with the U.S.S.R. However, the disposition of tritium from weapons submitted for destruction should not be discussed.

It is the U.S. position that enough production of tritium should continue under a cutoff to compensate for the radioactive decay of the tritium in the weapons inventory and the stockpile, and to provide for non-weapons uses. Uranium-235 required to fuel reactors for producing tritium for weapons replenishment would be obtained from existing stockpiles.

A possible limitation on the amount of allowed production of tritium might be obtained by requiring that equivalent amounts of helium-3 be turned in. Results of an AEC study have shown that the decay of tritium is the only practical source of significant quantities of helium-3. However, tritium production rates are highly classified at this time and declassification would be necessary before any discussions that would reveal these rates could take place.

B. Political Considerations Regarding Cutoff-Transfer Proposal

Pressures from the non-nuclear-weapon countries for concrete measures of armaments reduction by the nuclear-weapon powers are likely to increase, particularly during the period when the non-proliferation treaty (NPT) has been signed but not yet ratified by many countries. Key non-nuclear-weapon states will probably demand that the nuclear powers make progress toward disarmament by agreeing to measures that would constitute a “balance of obligations.” While the non-nuclear-weapon nations will be serving their own interests by accession to the NPT, they will nevertheless strongly urge that the nuclear-weapon powers also contribute to the stability of the international scene and take steps to reduce the likelihood of a future nuclear conflict. It is likely that some non-nuclear-weapon states will attempt to make such steps by the nuclear-weapon powers a condition for their signature, ratification, or continued adherence to the NPT.

One measure that the non-nuclear-weapon states have suggested as contributing to a suitable balance of obligations and which the United States has already proposed is a complete cessation of the production of fissionable materials for weapons uses. The destruction of a number of nuclear weapons and the transfer of the resulting fissionable materials to peaceful uses is a related measure which the U.S. has also proposed at the ENDC. These measures would constitute a logical post-NPT approach by the nuclear-weapon powers to a “balance of obligations.”

1. Source: Washington National Records Center, RG 383, Central Policy File: FRC 85 A 83, Committee of Principals Memo dated July 2, 1968 re “Cutoff.” Secret; Limited Distribution.
2. ENDC/134, June 25, 1964. [Footnote in the source text. Regarding this 1964 initiative, see Documents 30, 32, 33, and 35, especially footnote 6 thereto.]
3. Regarding the 1956 initiative, see Foreign Relations, 1955–1957, vol. XX, pp. 320, passim.
4. Secret.
5. See footnote 6, Document 220.
6. Secret; Restricted Data.