LAS VEGAS, Feb 24: British and US government scientists performed an underground nuclear experiment, short of a nuclear blast, at the Nevada test site this week, the National Nuclear Security Administration said on Friday.

Thursday’s experiment involved detonating high explosives around radioactive material in a vault about 300 metres below ground at a remote part of the desert testing range 135kms northwest of Las Vegas.

No radioactivity was released in the subcritical experiment, said Nancy Tufano, spokeswoman for Bechtel Nevada, a contractor at the nuclear security administration in North Las Vegas. Scientists for the first time posted a nearly eight-minute video Web log of preparations for the experiment.

Tufano described the material tested as specially processed nuclear plutonium, but said she could not disclose the isotope for security reasons.—AP