Less than Critical

The United States last week conducted a subcritical nuclear experiment to collect data to help the nation maintain a safe and reliable nuclear weapons stockpile, announced the National Nuclear Security Administration, an agency of the Energy Department. Dubbed Pollux, the plutonium-based experiment took place on Dec. 5 at the Nevada National Security Site in southern Nevada, northwest of Las Vegas, according to NNSA. “Challenging subcritical experiments maintain our capabilities to ensure that we can support a safe, secure, and effective stockpile without having to conduct underground testing,” said NNSA Administrator Thomas D’Agostino, in the agency’s Dec. 6 release. The United States last conducted an underground nuclear weapons test in September 1992. A new diagnostic tool used in Pollux “resulted in more data collected in this single experiment” than in all other previous subcritical tests, said NNSA Deputy Administrator for Defense Programs Don Cook. The data help ensure that “computer simulations can accurately predict performance,” of the nuclear weapons, he noted. Subcritical experiments produce no critical mass that would sustain a nuclear chain reaction; thus, there is no nuclear explosion, according to NNSA. Pollux was the 27th subcritical experiment to date. The previous one, Barolo B, took place in February 2011.