USAEC Meeting 1377
Germantown, Maryland, May 28, 1958, 10:15 A.M.
**Warning** — There are many DELETED items specifying wording of high confidentiality
WEAPONS TEST LIMITATIONS
Mr. Graham reviewed with the representatives of the AEC weapons laboratories several events which had led the Commission to request a meeting with them to discuss the question of weapons test limitations. He pointed out that the General Advisory Committee and the Advisory Committee on Biology and Medicine had considered the subject of weapons tests at their recent meetings. In addition, the current congressional authorization hearings were concerned, in part, with funds to be authorized for the weapons test program. Mr. Graham said the tents had made it evident that future weapons testing was still unresolved. Therefore he and other Commissioners believed it would be helpful if a complete discussion of the subject could be held with representatives from the weapons laboratories. General Starbird added that the Laboratory Directors had, been requested to consider what technical problems were involved and what limitations would result from a decision to test underground only.
Mr. Teller began the discussion by stating that scientists at Livermore Laboratory had concluded that nearly all the information needed by the U. S. about nuclear explosions could be obtained from underground tests and that secret weapons testing is more easily carried out than testing above ground. He said he would favor conducting future weapons tests underground regardless of whether an international test limitation should be agreed upon. He added, however, that before it could be known with certainty that weapons in the megaton range could be successfully tested underground, there would have to be a series of tests gradually increasing in size to the megaton range. In addition, if all tests were conducted underground, there would be no opportunity to test weapons effects or to proof-test anti-ICBM missile systems. Therefore, he recommended that it would be desirable to have some above-ground testing each year but limit each country to tests placing a maximum DELETED of fissionable material in the atmosphere yearly. This amount of above-ground testing, he said, would permit all the diagnostic weapons experimentation necessary for the weapons program. If the maximum amount of fissionable material which could be put into the atmosphere each year by each country were limited DELETED, it would still be possible to conduct valuable above-ground tests, although the amount of information gained would be less, and the results would be limited.
Mr. Brown discussed with the Commissioners the three major types of measurements for a weapons test and how accurate these measurements would be if applied to an underground detonation. He said the yield measurement for the Rainier shot had a margin of error DELETED, but with additional experimentation, this margin could be brought down DELETED. Mr. Teller remarked that weapons yields could not be quite as accurately determined underground as above-ground. However, he said that diagnostic details from direct measurements can be obtained more efficiently and accurately underground than above-ground.
Mr. Brown said that, in his opinion, radio-chemistry measurement techniques for underground tests, although not as accurate as yield measurements, are adequate. Reaction history measurements, he said, can be more accurate underground than above-ground. Mr. Brown said he agreed with Mr. Teller that all necessary above-ground experiments could be conducted within the limitation DELETED DELETED. . . . to keep within this limitation, he said it would probably be required to substitute clean weapons for average weapons shots. Mr. Brown noted special weapons types would have to be developed for effects testing and anti-missile missile warheads to be detonated underground.
Mr. Brown said the best information available to him indicated that weapons DELETED could be tested safely underground, but, as Mr. Teller had stated, the size of the tests would have to be detonated deeper and in much harder rock. There is uncertainty about the effect of such detonations since the transmission of shock would be more direct.
Mr. Sewell reviewed with the Commissioners the advantages of an underground test program over the present series of yearly above-ground test programs. Greater flexibility in scheduling tests and, therefore, more rapid progress in developing new weapons would be possible if the laboratories were not restricted to waiting for only one test series each year. With an underground test program, tests could be conducted periodically throughout the year whenever a weapon under development reached the point where specific test experiments needed to be undertaken. More radical weapons designs could be tested because a laboratory would know that if a particular test failed, a year would not have to lapse before it could conduct another test experiment. This fact could also lead to more rapid progress in weapons development. Costly, full-scale test operations such as are shown in alternate years at the Pacific Proving Grounds could be eliminated. Tests would no longer be dependent upon weather conditions, thus saving additional time and money now consumed in conducting above-ground tests. The cost of digging the tunnel for the Rainier shot price no more than a five-hundred-foot tower for a test device, and the cost of digging new tunnels out from a main one is about one-fourth the cost of the original tunnel, Mr. Sewell said. In addition, public opposition to the tests because of the fallout danger could be eliminated by underground testing.
Mr. Teller stated that conducting all future U.S. weapons tests underground would interfere somewhat with Project PLOWSHARE, the program for developing peaceful uses of nuclear explosive devices.
In response to a question by Mr. Fields, Mr. Sewell said as many DELETED bombs could be detonated in a single mountain.
Mr. Bradbury commented that although the Livermore scientists may be correct in believing that nearly all necessary weapons information could be obtained from underground testing, the U.S. would be challenged if actual experience proves this incorrect. He pointed out that much of this work on megaton weapons now involved detailed improvements of the guns and that with only underground testing, there would be a greater risk of being misled about what the tests demonstrated. Mr. Bradbury said he took the position that a diversified testing program using balloons, towers, and underground tunnels would be preferable to a complete confidential test program.
Mr. Teller remarked that data on a weapons test is most needed when that device misfires and that the diagnostics of such a test could be done as well or better if the shot were underground rather than above ground.
General Starbird pointed out that estimates regarding a major underground test program are being based to a large extent upon extrapolations from the Rainier shot. He said he concurred with Messrs. Bradbury and Graves that the U.S. would face a severe military problem if it agreed to underground testing for all weapons and then discovered that the larger weapons could not be tested underground. He added that the public could not be expected to raise questions about the safety of even underground weapons tests and the danger that the radioactivity created by the detonation might sometimes contaminate water and plant life.
Mr. Graves said he favored using balloons for testing weapons devices and that this valuable testing technique would be lost if all above-ground tests were halted.
Mr. Teller stated that there would be no chance that radioactivity from underground tests could contaminate animals or humans. He said he believed one could be overly cautious about questioning the feasibility of confidential testing.
Mr. Vance referred to a statement by the GAC at their 58th meeting that the Commission must not wait too long in proposing an intermediate position between unlimited testing and a ban on all weapons testing. Alternatives suggested by Mr. Vance included:
- A limitation on the amount of radioactivity released into the atmosphere
- Supervision by the U.N. of all weapons tests
- Complete underground testing of all weapons. Mr. Vance said he favored the confidential testing position because it would be the simplest to establish and end any radioactive contamination of the atmosphere from weapons detonations. He said that public concern with the question makes it an important consideration, even though the Commission recognized that the danger at present is negligible. Mr. Vance said the question he wished the representatives of the laboratories to discuss is what intermediate position would enable the U. S. to continue its weapons development program with the greatest freedom. Mr. Bradbury said it would be challenging to select the best alternative since each would interfere with the possible development under unlimited testing.
Mr. Teller said he believed the most desirable alternative would be to restrict above-ground testing by each country to DELETED fission products released into the atmosphere each year and to require that all other tests be conducted underground. Such a position would have several advantages, he said. It would permit the development of anti-missile missiles, which probably would be impossible if all testing had to be conducted underground. It would also make it quite tricky for nations that do not now have weapons capability to develop weapons. They would be forced to create tiny weapons for underground testing and clean devices for above-ground testing. Finally, an agreement to limit the amount of fissionable material released into the atmosphere would necessitate establishing a mutual inspection system, thus allowing U.S. observers to gain first-hand information about the Soviet weapons program.
Mr. Teller said he would be reluctant to have the U.S. accept more stringent test limitations that the DELETED fission yield per year above ground and unlimited underground testing.
Mr. Vance observed that Mr. Teller’s arguments were quite logical; however, the question of limiting nuclear tests would not necessarily be resolved on a rational or strictly scientific basis. He cited Mr. Hans Bethe’s recent statements that all atomic testing should be halted as a first step in ending the arms race and reducing world tensions. He said these are political judgments, not scientific ones, although a scientist makes them.
Mr. Floberg asked Mr. Teller how possible violations of limitations, such as those he recommended, would be handled. Mr. Teller replied that he would not be too concerned if the offense were in the range DELETED of fission yield put into the atmosphere in a single year DELETED. However, he said violations substantially more significant than this would be a cause for serious concern. He pointed out that all countries carrying out an atmospheric sampling program would know when serious violations had occurred. General Starbird remarked that continued violations of such a limitation might cause neutralist countries to conclude that the restriction was ineffective and demand a complete cessation of all weapons testing.
Mr. Strauss questioned how to complete weapons systems that could be proof-tested underground. Mr. Bradbury said he was not convinced that a final proof test of a missile and warhead was necessary if the two could be adequately tested separately. Mr. Teller said a significant amount of experimentation was still required for an anti-ICBM missile warhead and that some above-ground testing would be necessary.
Mr. Strauss then inquired whether fallout measurement techniques are accurate enough to determine precisely whether a particular country had placed DELETED fission yield in the atmosphere. Mr. Teller replied that this would be possible only if there were mutual inspections within the countries where the tests occurred.
The question of identifying which country particular fallout originated was then discussed by Mr. Strauss and Mr. Teller. Mr. Strauss postulated that a country might detonate several weapons at extremely high altitudes, with the fallout not being detected until a year later. He asked whether it would be possible to determine which country was responsible for those tests accurately. Mr. Teller said satellite counters could detect almost immediately when high-altitude shots have been detonated. Still, the country carrying out the trial could not be positively identified in such cases. He added, however, that scientists could probably make an intelligent guess about the origin of the shots.
Mr. Vance left the meeting briefly during the above discussion. The Commissioners returned to the necessity of proof-testing complete weapons systems. Mr. Graham inquired whether testing missile systems using chemical rather than nuclear warheads would be satisfactory. Mr. Teller said it would be possible to try a missile system without the atomic warhead and determine the performance of such things as the timing of the detonation device. Still, of course, such a test would not provide any information on the effects of a nuclear explosion. Mr. Floberg said he believed there had been many examples of the importance of conducting trials of complete weapons systems, such as submarine torpedos. He was unconvinced that proof-testing the entire missile system would be unnecessary. He said the Psychological factor of working with missiles equipped with nuclear warheads was vital in itself.
Mr. Fields then discussed with Mr. Teller and Mr. Graves when it would be possible to carry out the first diagnostic tests of an anti-ICBM missile. Mr. Brown said the Air Force had mentioned 1960 when such tests might be held; however, the weapons laboratories do not yet know what device might be used. Mr. Teller said the DELETED might be a basis for developing such a weapon, but much more experimentation is required before it can be perfected. Following the detonation DELETED at Operation HARDTACK, it might be possible to conduct further tests of it in 1959. Mr. Graves believed it would probably be 1960 before an anti-ICBM device would be ready for diagnostic testing.
Mr. Strauss concluded the discussion by expressing the Commissioners’ appreciation to Messrs. Teller, Bradbury, Graves, Brown, and Sewell for an enlightening discussion of the test limitations questions.
W B. McCool, Secretary