American satellites last week detected some construction work at the Novaya Zemlya nuclear test site, prompting some to speculate that Russia–which has signed the Comprehensive Test Ban (CTB) treaty–might be preparing to resume nuclear testing. Such charges prompted a speedy Russian denial. First Deputy Atomic Energy Minister Viktor Mikhailov did, however, admit that Russia planned to continue its program of so-called “subcritical” testing. Such tests involve a small amount of fissile material and are designed to bring this material close to–but short of–the state of criticality in which a nuclear chain reaction sustains itself. The explosion they produce is chemical in nature rather than nuclear. Both Russia and the United States have conducted these sorts of tests, ostensibly to verify the safety of their nuclear weapons stockpiles. The most recent American test was conducted on September 27.
Arms control advocates have criticized subcritical tests, claiming that it is very difficult to distinguish them from the slightly larger–and banned–“hydronuclear” tests. These do produce a very low nuclear yield. Scientists use seismic measurements to verify the CTB. While these measurements can usually place an upper limit on the explosive yield of a test with reasonable accuracy, they cannot readily distinguish between very small chemical and nuclear explosions.
The Japanese have criticized both Russia and the United States for conducting subcritical tests. The Hiroshima branch of a Japanese antinuclear group last Saturday sent a letter to Russian President Boris Yeltsin protesting the Russian preparations. The mayors of Hiroshima and Nagasaki strongly condemned the U.S. test. And on Sunday Japanese Prime Minister Keizo Obuchi said Japan wanted to discuss subcritical nuclear tests at the international level (Russian and international media, September 24-27).
ABDUCTORS OF YELTSIN’S CHECHEN ENVOY READY TO SWAP HIM FOR WARTIME LEADER.