Scientists conduct subcritical nuclear experiment in Nevada

LAS VEGAS (AP) -- Government scientists conducted an underground nuclear materials experiment Friday at the Nevada Test Site, the National Nuclear Security Administration said.

The subcritical experiment, dubbed Piano, involved detonating high explosives to chart the behavior of plutonium in a non-nuclear explosion. It did not trigger a self-sustaining nuclear reaction, NNSA spokesman Kevin Rohrer said.

Scientists from the Lawrence Livermore National Laboratory in California completed the test at 1:44 p.m. in a cavern 960 feet below ground, Rohrer said. No abnormalities and no surface damage were reported at the vast site, about 85 miles northwest of Las Vegas.

Federal officials say subcritical experiments are essential to maintaining the safety and reliability of the U.S. nuclear arsenal.

Piano was the 20th subcritical experiment since the program began in 1997. The most recent one was called Rocco, conducted on Sept. 26, 2002.

Anti-nuclear groups have criticized subcritical experiments as contrary to the spirit of the 1996 Comprehensive Test Ban Treaty on nuclear arms. The experiments technically do not violate the treaty because no critical mass is formed and there is no full-scale nuclear explosion.

The Bush administration said last year it wants the Nevada Test Site to be prepared to resume full-scale nuclear tests within 18 months -- about half the time it would take to prepare for such experiments today.