U.S. Begins Nuclear Tests in Nevada

The United States began a round of controversial underground nuclear weapons-related tests Wednesday in the Nevada desert, an Energy Department spokeswoman said.

The experiments, announced earlier, were designed to test weapons materials without triggering the kind of nuclear chain reaction prohibited by an international treaty signed last year.

The government exploded a total of 160 pounds of chemicals in a tunnel 960 feet underground, to measure the impact on plutonium under high pressure, said LaTomya Glass, a spokeswoman for the department’s Nevada operations.

Antinuclear groups blasted Wednesday’s so-called subcritical experiment, saying it violated the spirit of the test ban, but the Clinton administration said it had complied with the terms of the pact. The administration said the tests, which involve massive supercomputer calculations, were needed to assess how age would affect the materials in the U.S. nuclear arsenal and predict weapons performance without actual explosions.