Volume #17 - 821.|
RELATIONS WITH THE UNITED STATES
Memorandum from Defence Liaison (1) Division
to Under-Secretary of State for External Affairs 109
February 10th, 1951|
SOME TECHNICAL AND POLITICAL COMMENTS ON NEVADA ATOMIC TESTS|
It may be worth while to set on paper a few observations suggested by the recent atomic tests held near Las Vegas, Nevada. It should be emphasized that our speculation on the type of explosions that have taken place during these tests is not based on technical knowledge of atomic weapons nor on any restricted information concerning the tests. There have been so many wild statements reported, however, that it is easier to say what the explosions were not than what they were. No doubt Dr. Solandt will in due course have accurate information as to what has been taking place, and some indication of the U.S. Atomic Energy Commission's evaluation of the scientific and military information obtained. This memorandum simply presents a few guesses as to some of the technical and political factors involved.
I. Technical Factors
1. Five explosions have been reported, the first four in two pairs and the fifth separately. Each of the pairs consisted of a relatively mild explosion first, followed within twenty-four hours by a much more powerful one. The fifth explosion appears to have been considerably more powerful than any of the others.
2. While there has been virtually no information released concerning the nature and purpose of the tests, one might speculate somewhat as follows. Earlier tests have been concerned with the atomic weapon as a bomb pure (if one may use the term) and simple. Technical developments have continually been increasing the destructive energy which such a bomb can release, and this trend has been reported periodically to the press. Perhaps the fifth and most powerful of the recent explosions was a test of the most up-to-date weapon of this type.
3. Of late, however, there has been a focusing of interest upon the possible use of atomic bombs as tactical weapons. The two obvious types would be artillery shells and guided missiles. In either case one might expect some sacrifice of power in the interest of effective design of the weapon for tactical use. Very possibly the first four of the present explosions have been tests of weapons of this sort. The milder explosion in each pair might represent primarily a test of the weapon in its nonnuclear aspects with only minimal provision of bomb components for the testing of firing mechanisms, and the subsequent more powerful explosion a fully charged test designed to permit estimation of the weapon's tactical efficiency.
4. Press comment has been concerned with the development of a "limited atomic explosion", suitable for tactical use, with the implication that there is some advantage in having available weapons which release energy in an amount between an ordinary H.E. bomb and a full scale atomic bomb. While it is possible that there might be some military advantage in having a weapon producing less than the full destruction of an atomic bomb as hitherto understood, the use of such a weapon could not, it is believed, represent any appreciable saving in nuclear fuel. A certain critical mass of nuclear fuel is, of course, required for any nuclear explosion, large or small, and for any but the most powerful atomic bombs it is likely that but little more than this minimum is sufficient. The effectiveness of an atomic bomb is in all probability determined primarily by the method whereby the nuclear energy is released and strength of the casing to contain the explosion as long as possible, and only secondarily by the amount of fuel, provided, of course, that this exceeds the aforementioned minimum.
5. In this light, it appears that utilization of scarce nuclear fuel in weapons of less effect than atomic bombs of the type previously tested would not be sufficiently economical to justify a programme for the development of such limited tactical weapons. Hence press suggestions of a "fizzle explosion" weapon would appear to be unjustified or misinformed.
6. The most likely explanation as to what kind of atomic weapon was being tested was implied in General Collins' interview last Monday, February 5, when he volunteered the information that atomic artillery shells are "wholly possible" and "in the not-too-distant future". 110 He added more cautiously that it would be "many years" before guided missiles with atomic warheads would be available, but said that guided missiles themselves would be ready for use "inside of eighteen months". It would therefore appear that the Nevada tests consisted of four tests of a "tactical bomb" followed by one test of the most powerful type of "improved bomb" developed since Bikini.
II. Political Factors
1. Both the Alsops111 and Reston have suggested, in articles that may or may not have been "inspired", that the timing of the Nevada tests was deliberately intended to serve as a reminder to the world at large and the Russians in particular that the main strength of the United States lay at present in its atomic superiority and its superior capacity in inter-continental strategic bombing. The USSR and the People's Government of China have, during the past few months, shown a surprising readiness to take additional risks of an outright war with the United States, and the Nevada tests may be intended to draw attention to the fact that the United States in Korea has, so to speak, been fighting with its right hand tied behind its back.
2. Reston specifically links the tests with the increasing pressure being placed on Yugoslavia by the military build-up in the surrounding satellite states which has led to some apprehension that an attack on Tito might be impending. The Alsops have also mentioned the Yugoslav situation, but have written in more general terms, in an article, attached,t about "Unfreezing the Asset". If "inspired", these articles imply a United States decision to give serious consideration, at least, to using the bomb in the event of a Soviet or satellite attack on Yugoslavia. If such a decision is in fact being considered by the United States Government, it would mean almost as much for Yugoslavia as inclusion in the North Atlantic Treaty. Although relaxation of export controls on strategic materials has been discussed in the North Atlantic Council Deputies, there has been no previous hint of such a strong U.S. policy in support of Tito.
3. One further indication that the Alsop and Reston articles have been inspired is that at least one member of the U.S. Joint Congressional Committee on Atomic Energy has as much as told the press that in private session the Committee had discussed the international effect of the Nevada tests.
4. The tests have no doubt also had a domestic political effect in bolstering U.S. confidence in their own strength, and helping to offset to some extent the Korean reverses, while building up public confidence in the progress of the U.S. Atomic Energy Commission's weapons development programme.
5. We are not suggesting that the Nevada tests were timed solely for political reasons, but only that the timing may also have been convenient for political purposes.112
109 Note marginale :/Marginal note:
110 Voir/See New York Times, February 6, 1951.
111 MM. Joseph et Stewart Alsop, auteurs de « Matter of Fact»
, chronique souscrite au New York Herald Tribune.
112 Note marginale :/Marginal note: