A nuclear weapon with a yield of less than 20 kilotons was triggered 1,000 feet beneath the Nevada desert Wednesday in the second announced U.S. test of the year.
A spokesman for the Department of Energy said the test, code-named Tornero, was conducted at 8:45 a.m..
"No radiation leaked into the atmosphere, and the test was a success," the spokesman said.
Six anti-nuclear activists picketed the gates of the Nevada Test Site on Wednesday. One was arrested on charges of trespassing, the government said.