Fourth subcritical nuclear test conducted at Nevada Test Site

Sunday, Sept. 27, 1998 | 12:05 p.m.

So-called subcritical experiments are done without nuclear testing since a moratorium that went into effect in 1992, said Robin Staffin, the Energy Department's deputy assistant secretary for research and development in Washington, D.C.

The experiment, at the test site about 85 miles northwest of Las Vegas, is designed to obtain physics information on plutonium samples of varying ages. It was conducted in a series of horizontal tunnels about 960 feet underground.

The experiment remained subcritical, and no self-sustaining nuclear chain reaction occurred, Staffin said.

The DOE conducted two similar experiments last year and another one in March, the first nuclear-related experiments at the Nevada Test Site since the 1992 moratorium went into effect. There is no forecasted termination of the tests.

The DOE contends the experiments are essential to the nation's program to maintain the safety and reliability of the nuclear weapons stockpile in the absence of underground nuclear testing.

In the past, subcritical experiments have drawn protests from anti-nuclear groups who claim the tests are part of a nuclear-testing program.