Thoughts on Verification of Nuclear Disarmament

It is my pleasure to be here to day to participate in this Conference. My thanks to the organizers for preparing such an interesting agenda on a very difficult topic. My effort in preparing my presentation was performed under the auspices of the U.S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48. And as many of you know Lawrence Livermore National Laboratory is now, as of Oct 1st, under contract to the Lawrence Livermore National Security LLC. There has been a long history of how to view verification of arms control agreements. The basis for verification during the days of SALT was that verification would be based on each country's national technical means. For treaties dealing with strategic missiles this worked well as the individual items subject to verification were of such a size that they were visible by the National Technical Means available at the time. And it was felt that the counting of missiles and launchers could be verified by our National Technical Means. For nuclear testing treaties the use of seismic measurements developed into a capability that was reasonably robust for all but the smallest of nuclear tests. However, once we had the Threshold Test Ban Treaty, there was a significant problem in that the fidelity of the measurements were not sufficient to determine if a test was slightly above the 150 kt limit or slightly below the 150 kt limit. This led some in the US to believe that the Soviet Union was not living up to the TTBT agreement. An on-site verification protocol was negotiated in 1988 and 1989 that allowed the US to make hydrodynamic yield measurements on Soviet tests above 50 kt yield and regional seismic measurements on all tests above 35 kt of yield; and the Soviets to make the same type of measurements on US tests to ensure that they were not over 150 kt. These on-site measurements were considered reasonably intrusive. Again the measurement capability was not perfect and it was expected that occasionally there might be a verification measurement that was slightly above 150 kt. But the accuracy was much improved over the earlier seismic measurements. In fact some of this improvement was because as part of this verification protocol the US and Soviet Union provided the yields of several past tests to improve seismic calibrations. This actually helped provide a much needed calibration for the seismic measurements. It was also accepted that since nuclear tests were to a large part R&D related, it was also expected that occasionally there might be a test that was slightly above 150 kt, as you could not always predict the yield with high accuracy in advance of the test. While one could hypothesize that the Soviets could do a test at some other location than their test sites, if it were even a small fraction of 150 kt it would clearly be observed and would be a violation of the treaty. So the issue of clandestine tests of significance was easily covered for this particular treaty