Global Security Newswire

The United States in November fired its Z machine on a plutonium cache in a fourth test designed to aid in sustaining the U.S. nuclear arsenal, National Nuclear Security Administration insiders told Kyodo News on Friday (see GSN, Jan. 6).

The trial took place on Nov. 16 at the Sandia National Laboratories in New Mexico, the sources said.

The newly revealed Z machine plutonium test was preceded by three similar trials in 2010 and 2011. The device can generate X-rays of unparalleled intensity to mimic the fusion reactions of nuclear warheads; it allows for study of plutonium reactions under high pressure and heat levels like those of a detonating nuclear bomb, according to the National Nuclear Security Administration.

The Z machine experiments supplement a separate series of subcritical nuclear trials, the semiautonomous Energy Department office has said (see GSN, July 20, 2011). The United States conducted its most recent nuclear test detonation 20 years ago. It began the subcritical experiments in 1997 and the additional plutonium trials in 2010 to help ensure the upkeep of its aging nuclear weapons (Kyodo News/Mainichi Daily News, Jan. 7).