308. National Intelligence Estimate0
THE SOVIET ATOMIC ENERGY PROGRAM
The Problem
To estimate the current status and probable future course of the Soviet atomic energy program to mid-1968.
Principal Conclusions
Nuclear Testing and Technology
1. The Soviets have a highly developed nuclear weapon technology which differs in design philosophy and emphasis from that of the West. They have tested thermonuclear devices in very high yields (up to 63 megatons) well above any in Western experience, and in this range have achieved an outstanding yield-to-weight performance. They have also shown an excellent performance in thermonuclear devices of lower yields, down to about two megatons. In the submegaton thermonuclear class, [2 lines of source text not declassified] and they have not yet demonstrated a thermonuclear capability in weights below about 600 pounds.
2. The Soviets have conducted many tests below 50 kilotons, some of which may not have been fission devices. Debris from a number of tests in 1961-1962 was not obtained and analysis of those 1962 tests for which debris was obtained has not been completed. In general, data from the 1961-1962 devices analyzed to date do not permit any definitive judgment as to their progress in fission weapon technology, particularly in the very low yield category where evidence of testing may have been [Page 761] missed. They have continued to show interest in unboosted fission devices, although they have also tested many well-boosted devices.
Weapon Stockpiles
3. A small number of individually produced weapons for interim use could be fabricated within a few months after device testing. Thus, a few weapons with very high yields of up to 100 MT could now be available. However, we believe that the Soviet time lag between nuclear tests of a device and initial stockpile entry of a serially produced weaponized version is about two years at a minimum. On this basis, some of the new devices tested in 1961 could be entering stockpile during the latter part of 1963 if a priority development is assumed. It is estimated, however, that this could be done only on a limited scale, and that, in general, the devices tested in 1961-1962 would be stockpiled in 1964 and 1965. We believe that weapons currently stockpiled are derived primarily from devices tested in 1958 or earlier; these weapons range in yield from a few kilotons up to 6 megatons.
Requirements for Further Testing
4. Soviet nuclear weapon technology appears to be highly sophisticated and adequate for present delivery systems, but significant advancements can still be made through further development and testing. Probably one of the strongest requirements is in the area of high-altitude effects of nuclear weapons. The Soviets conducted several such tests in 1961-1962, but probably need additional tests to obtain weapon effects data pertinent to antimissile development and countermeasures. They also lack direct information on effects of high-yield weapons on hardened ground targets and on the effects of lower-yield weapons on deep underwater targets. The Soviets probably also have requirements to conduct further tests to improve yield-to-weight ratios particularly in the lower weight range and to develop new weapon capabilities such as light-weight thermonuclear warheads for smaller missile systems, very small weapons for tactical employment, weapons with enhanced radiation output, and weapons with minimal residual radiation.
5. We believe that the Soviets are continuing a vigorous weapons research and development program, and that they are maintaining a posture to resume nuclear testing promptly if a decision is made.
Fissionable Materials Production
6. We estimate the mid-1963 cumulative Soviet production of fissionable materials at about 15,000 kilograms of plutonium equivalent and 130,000 kilograms of U-235.1 These quantities are somewhat lower [Page 762] than previously estimated for mid-1963, as the result of further analysis and additional evidence. The Soviets are continuing to expand their fissionable material production capability at a significant rate. We estimate that by mid-1968 cumulative production will amount to about 35,000 kilograms of plutonium equivalent and 380,000 kilograms of U-235.
Reactor Development
7. Soviet research reactor development continues to be competent in most areas and is unique in a few. However, the original, unrealistic Soviet nuclear electric program has been abandoned and they are now proceeding with one which is more commensurate with their economic requirements and the state of their reactor technology. Moreover, the Soviets have encountered numerous difficulties with the nuclear propulsion of the icebreaker Lenin, and there is considerable evidence of similar difficulties with Soviet nuclear powered submarines. Soviet work on ion propulsion and nuclear auxiliary power supplied for space applications is continuing, and we believe that they have a program to develop materials suitable for nuclear rocket motors. The Soviet aircraft nuclear propulsion program appears to have been delayed and may have been cut back or even canceled.
[Here follow a 44-page summary, a 33-page Discussion section, and an evaluation of Soviet nuclear tests from August 1949 to December 1962.]
- Source: Johnson Library, National Security File, National Intelligence Estimates, 11-63, USSR. Top Secret; Restricted Data. A table of contents is not printed. A note on the cover sheet reads: “This estimate was prepared and agreed upon by the Joint Atomic Energy Intelligence Committee which is composed of representatives of the Central Intelligence Agency and the intelligence organizations of the Departments of State, Defense, the Army, the Navy, the Air Force, AEC, NSA, and FBI.” The members of the U.S. Intelligence Board concurred except the Assistant Director of the Federal Bureau of Investigation who abstained because the subject was outside his jurisdictions.↩
- See page 35 for the views of the Assistant Chief of Naval Operations (Intelligence). [Footnote in the source text.]↩