Foreign Relations of the United States, 1948, General; the United Nations, Volume I, Part 2

Department of State Atomic Energy Files

Memorandum by Mr. R. Gordon Arneson to the Acting Secretary of State

top secret

[Washington,] September 27, 1948.

Memorandum for the Acting Secretary

Subject: U.K. Request for Information on Atomic Weapons

A. Background

1. On September 1 [2], 1948 Admiral Sir Henry Moore handed Secretary Forrestal a note¹ from the U.K. Minister of Defense asking for his views on a proposal to extend the areas of interchange to include information on atomic weapons. To the note was appended a list of specific topics on which information was being sought (Tab A). Copies of the foregoing were given the Department and the AEC a few days later.

2. Certain events antecedent to this request are germane.

a. On March 19, 1948 Donald Maclean informed Mr. Gullion that the U.K. had been engaged on research and development work on atomic weapons since the beginning of 1947.² This information was communicated by Mr. Gullion to the Secretary, yourself, and Carroll Wilson. Shortly thereafter this fact was stated by the U.K. Government in response to a parliamentary question, and stories to the same effect have appeared in both the British and American Press.

b. At a meeting of the American side of CPC on July 6,³ Mr. Lilienthal reported that AEC technicians engaged in discussions with U.K. technicians on Area 8 “Design of Natural Uranium Reactors in which the Power Generated is not Wasted,” observed that the U.K. effort in this area appeared to be directed toward design of reactors for production of plutonium (i.e. power wasted) rather than power reactors (power not wasted). Accordingly the U.S. technicians did not furnish information on this area. The American side CPC concluded that this development should not change the decision spelled out in the January 7 modus vivendi⁴ for exchange of information in nine specified areas.

c. In late July 1948 another group of AEC technicians headed by Cyril Smith went to the U.K. to exchange information in Area 6 “Fundamental Properties of Reactor Materials.” Initial instructions given them by Dr. Fisk, Director of Research, and Carroll Wilson authorized exchange on basic metallurgy of plutonium. On learning of these instructions Senator Hickenlooper, Dr. Bush, and Mr. Carpenter lodged strong objections with Sumner Pike, Acting Chairman of AEC, who telephoned Cyril Smith in London in time to prevent discussion of this subject. As a result of this episode a procedure has been agreed whereby the Military Liaison Committee passes upon all proposed agendas of discussions within the nine areas. Instructions to our representatives in every instance now contain the following statement:

“While recognizing that a distinction between atomic energy matters of military significance and of non-military significance cannot be clearly made, all exchanges shall be further governed by the general criterion that information specifically relating to weapons or to the design or operation of present plants for production of weapons materials or weapons parts is not subject for discussion.”

d. On August 16, Mr. Carpenter stated to Dr. Woodward, Scientific Attaché to British Embassy, that the fact that the U.K. was placing primary emphasis in their reactor program on plutonium production had caused considerable concern to the Joint Congressional Committee and as a result exchange within the nine areas would have to be carefully “policed” to ensure that no substantial amount of information on weapons was exchanged. Mr. Carpenter stated that further expansion of exchange was quite improbable. He also asked whether the U.K. had considered the possibility of carrying on their work on plutonium and weapons production in Canada. Woodward stated that the U.K. Chiefs of Staff considered the U.K. as safe as Canada. (Tab B.⁵)

3. On September 16, Dr. Woodward again met with Carpenter at which time Carpenter expressed concern that the U.K. had gone ahead with weapons manufacture without prior discussion with the U.S. Woodward’s understanding was that the U.K. had undertaken to inform us of any important steps in their program. This they had done. Carpenter was surprised that the U.K. had come in with their request on September 1 [2] for weapons information in view of Carpenter’s statement to Woodward on August 16 that any expansion of areas of exchange was quite improbable. It appears that despite a recommendation from Woodward and the Ambassador not to do so, the Prime Minister directed that the request be submitted through the Military Establishment. (Tab C.⁶)

4. The British request of September 1 is now under consideration by the Jont Chiefs of Staff. In transmitting the request to the Joint Chiefs,⁷ Mr. Carpenter made it clear that he wished to have a preliminary judgment from the Joint Chiefs as regards military aspects but intimated that other factors would have to be given due weight. The Joint Chiefs have not yet come up with a recommendation although they are expected to do so rather soon. Webster (Carpenter’s successor) is anxious that the Joint Chiefs not produce a completely jelled opinion which would be difficult to alter on the basis of any other considerations that need to be taken into account.

B. Comments

1. Mr. Carpenter was clearly in error in stating that the British were committed to discuss with us in advance any plans to manufacture plutonium. Woodward’s interpretation to the effect that the U.K. was obligated to keep us informed is, on the record, the correct one. The British have in fact carried out this obligation by means of notification to Mr. Gullion on the 19th of March.

2. Within the terms of the understandings arrived at in the modus vivendi of January 7 one can find no basis for exchange of information on the basic metallurgy of plutonium. It was generally understood in this Government that information of substantial use in the production of plutonium, and therefore of the weapon, was not to be included in the areas of exchange. On the basis of the present agreement, therefore, it would appear that Senator Hickenlooper, Dr. Bush, and Mr. Carpenter, and finally the Commission itself, were correct in excluding this phase from the areas of exchange. That this is true is corroborated by the British themselves in their note of September 1 (See Tab A). Appended to that note is a list of topics, the first of which is entitled “Areas of Collaboration which would be of Great and Immediate Assistance to our Programme for the Design and Manufacture of Atomic Bombs.” The first item under this heading is “1. The metallurgy and methods of fabrication of plutonium with particular reference to its use in bombs.”

3. Whatever conclusion is ultimately reached on the British request it appears evident that the decision must rest on very broad grounds: whether it is in the security interests of the United States to have the U.K. join forces with us on atomic weapons. Such a decision cannot be taken solely on military grounds although military considerations perhaps loom largest, but must also take into account our political posture as well. Here the shape of our conversations on Western Union would appear particularly important.

4. Henderson (who replaced Maclean as British member of the Joint Secretariat) has spoken to me about the U.K. request on several occasions. He leaves the net impression that the British are anxious to have an early reply. I have told him that it would be most unwise to press too vigorously at this time for a decision. I have reminded him that the present election atmosphere and the simple fact that this is a major decision to be made by the Administration does not favor any quick action. There are indications that this advice has been seriously received, although it is too soon to tell.

5. It may be that if the U.K. does not see any early prospect of favorable action on their September 1 request they may wish to press again for a liberal interpretation of the 9 areas of exchange, particularly on the basic metallurgy of plutonium. In view of the firm opinions held by the Joint Congressional Committee, the Military Establishment, and the AEC on the last item it would appear most unwise for the U.K. to press for information in that field. This is the more so in view of their own admission that information on this matter would be of “great and immediate assistance to our program for the design and manufacture of atomic bombs.” This particular item is a microcosm of the larger request and involves essentially the same broad decision as to whether the United States and the U.K. should enter into a full partnership on atomic weapons.

6. It is suggested that if the British approach you in the near future on any aspect of this problem it might be useful to suggest to them not to become too impatient, that in the very nature of the request a decision may be a long time coming, that we consider they have fully complied with the requirement of keeping us informed of any major development in their work in this field, and that it would be a mistake on their part if discouraged by the prospects of a favorable reply on their request in toto to attempt to press for segments of it, especially basic metallurgy of plutonium.

R. Gordon Arneson

1. Ante, p. 750.
2. Gullion’s memorandum of his March 19 conversation with Maclean is printed, p. 700.
3. For the minutes of the meeting of July 6, see p. 719.
4. Ante, p. 683.
5. Memorandum of conversation not printed.
6. For memorandum of conversation, see p. 755.
7. Carpenter’s memorandum to the Joint Chiefs of Staff, September 14, requesting a preliminary judgment on the British request, has not been found in the files of the Department of State.

   In a memorandum of September 30, Clarence Wendel of the Office of the Under Secretary of State, informed Lovett that William Webster, who had become Chairman of the Military Liaison Committee, had indicated that on the previous day the Joint Chiefs of Staff had gone formally on record as strongly opposed to any expansion of the areas of exchange of information (Department of State Atomic Energy Files). The JCS memorandum to the MLC, September 29, has not been found in the files of the Department of State.