Over The Horizon

Verification Technology Questioned

The key to international nuclear-capability monitoring lies in detente, not sophisticated technology, according to Allan Krass, professor of physics and science policy at Hampshire College, Massachusetts, who toured Australia and New Zealand recently.

In his book Verification: How Much Is Enough?, Krass advocated the use of "national technical methods" (NTMs) of veri-fication -- such as seismic monitoring of nuclear tests and satellite monitoring to identify new nuclear facilities. In the case of the CIS and US in particular, however, the new spirit of cooperation has rendered such measures more trouble than they are worth.

One example quoted by Krass was the delayed ratification of the Threshold Test Ban Treaty (TTBT). Throughout the 80s, the Reagan administration accused the USSR of probable violation of the 150- kiloton limit for nuclear tests on the grounds of seismic data, and refused to ratify the TTBT until the Soviets accepted an allegedly more accurate on-site yield-measuring technique called CORRTEX.

With CORRTEX, a glass fibre is laid down a bore next to the test, and a light signal is used to measure the rate of destruction of the fibre during the detonation. When the Soviets agreed to allow CORRTEX verification, experiments showed that the CORRTEX method gave results consistent with seismic methods.

The large magnitudes associated with Soviet tests of similar yield to US tests were actually due to the differing geologies of the test sites. When a "bias factor" reflecting those differences was applied to seismic data, the recorded test yields conformed to the threshold limit. With the TTBT now ratified, the use of CORRTEX at any future tests will cost approximately US$10 million a shot, for no measurable increase in accuracy.

One of the problems that Krass identifies with other NTMs, such as satellite surveillance, is that in order for them to be comprehensive and effective they are inevitably expensive. If all the nuclear treaties currently under negotiation are ratified, it is estimated that one-time costs for the US alone would be US$645 million to US$3 billion. Further annual costs would amount to US$200-660 million.

Such a bill is out of reach of all but a few countries, and a strain even for them. Krass predicts greater demands by the US for "burden sharing" in verification. He also points to the underestimation of Iraq's nuclear weapons capabilities, which illustrates the dangers of relying on the intelligence capabilities of a single country, no matter how technically sophisticated they might be.

Krass also notes an interesting problem over and above questions of verification -- what should be done with the fissile material left over from the apparently inevitable dismantling of arms? At present there is no practical use for, or means of disposal of, plutonium. Weapons-grade uranium can be processed and used in reactors, but -- aside from the waste disposal problem -- the effect on the world uranium market of such "weapons dumping" would be catastrophic.

Tony Smith, NZSM Wellington