PM Files

The Secretary of State to the Chairman of the United States Atomic Energy Commission (Dean)1


Dear Mr. Chairman: International control of atomic energy is on the agenda for this fall’s session of the United Nations General Assembly. In the debates on this agenda item, it is the intention of the United States Government to continue its support of the United Nations plan of control.

In a letter dated April 20, 1950, I asked the Atomic Energy Commission for a current evaluation of the United Nations plan. In a letter dated June 26, 1950 from Sumner T. Pike, Acting Chairman, I received assurance that there have been no new scientific discoveries known to the Commission which altered the situation.

The Commission’s letter, however, identified two technical developments which might have some bearing on control problems and three major changes in the technical situation which have occurred since the plan was developed and approved.

It is important to be certain whether it would be technologically feasible to establish the type of control envisaged in the United Nations plan and, further, whether the plan, once established, would be effective.

One technical development mentioned in the letter indicates that it might be possible to produce not only plutonium from uranium and tritium from lithium, but also U–233 from thorium, without the operation of reactors. The United Nations plan makes no distinction between the controls which the international agency would exercise over uranium and thorium. Since the plan also provides that the international agency would own, operate and manage all facilities that make or produce dangerous quantities of nuclear fuel—which, by definition, includes both fusionable and fissionable materials—it would appear that the United Nations plan would meet the dangers inherent in this possible development. I should like the views of the Commission on this point.

The other technical development mentioned in the letter relates to the possible development of thermonuclear weapons. As the Commission’s letter states, an atomic explosion using plutonium, U–235, or U–233 is necessary to start a thermonuclear reaction. It follows then, if fission weapons were effectively eliminated, no thermonuclear weapon could be made. As for the point that tritium must be considered [Page 83] a “dangerous material”, the United Nations plan gives the agency the power to define “dangerous” materials. If we recall further that the United Nations plan gives to the international control agency the exclusive right to own source material, key substances, nuclear fuel and all facilities that make or produce these in dangerous quantities, it appears that the United Nations plan would effectively meet the dangers from the possible development of thermonuclear weapons. The views of the Commission on this point are also requested.

Mr. Pike’s letter of June 26, 1950, identifies three changes in the technical situation that have occurred since the first use of atomic weapons. In my opinion, the most significant one, from the viewpoint of international control, is the second; namely, the accumulation of stocks of nuclear fuel by more than one country. Apart from the problem of disposing of these stocks once the United Nations plan was accepted, there is the question as to how one can be assured that all accumulated stocks would, in fact, be turned over to international control. If there can be no adequate assurance on this point, it may well be that there is no plan of control, the United Nations or any other, which would prevent atomic weapons from appearing on the international scene without timely warning. I should appreciate the Commission’s advice as to the combination of scientific and technical methods that could be used to determine whether all significant stocks have been turned over to the agency, and the degree of certainty attaching thereto.

If the degree of certainty is very high, the first change in the technical situation mentioned in the letter, namely, the production of atomic weapons by the Soviet Union, can be coped with. Assurance that no stocks of nuclear fuel would be in the possession of any nation after the establishment of the plan could mean that atomic weapons could not get into national hands without warning.

The production of atomic weapons by the Soviet Union raises some problems concerning the establishment of any control system. However, it should be pointed out that during the development of the United Rations plan, it had always been kept in mind that not only the Soviet Union, but other nations would come into possession of atomic weapons. In the detailed spelling out of stages of transition from the present situation to one of international control, which has yet to be done, such capabilities would be taken into account.

The fact that hopes for a rapid development of atomic power have so far not been fulfilled is the third major change identified in the letter. It occurs to me that, among others, the possible development of the electro-nuclear method of generating neutrons might, by easing the uranium supply problem, have a bearing on the prospects for developing [Page 84] atomic power on a substantial scale. If this is so, it is perhaps difficult to improve on the provision incorporated in the United Nations plan designed to give flexibility in this matter to the international control agency, as technical developments might warrant. This provision is contained in Specific Proposal 12, Chapter 4, page 25 of the United Nations plan, which reads:

“The international agency shall keep the production of nuclear fuel, in a form suitable for ready conversion to use in atomic weapons, at the minimum required for efficient operating procedures necessitated by actual beneficial uses, including research and development. The agency shall not be authorized to increase existing stocks of nuclear fuel for any contemplated requirement, except where it is necessary to produce nuclear fuel for use in facilities whose location, design, construction and financing have been definitely decided by the agency and the nation concerned.”

Early receipt of the Commission’s view on the foregoing points would be helpful. The Fifth Regular Session of the General Assembly will be convened on September 19, 1950.

Sincerely yours,

Dean Acheson
  1. Commissioner Gordon E. Dean was appointed Chairman of the United States Atomic Energy Commission effective July 11, 1950.