美國能源部9月15日實施歐巴馬政府首度臨界前核子試驗Bacchus ，尚有後續

Bacchus Subcritical Experiment Conducted at NNSS

Bacchus, a subcritical experiment, was successfully conducted at 5:35 p.m. on Sept. 15, in an experiment room approximately 963 feet underground at the U1a Complex of the Nevada National Security Site (NNSS).

The experiment, conducted by Los Alamos National Laboratory, was the 24th subcritical experiment conducted to date at the NNSS.

The last experiment was Unicorn, which was conducted on Aug. 30, 2006. Subcritical experiments do not reach "criticality" where a self-sustaining nuclear chain reaction would occur; rather, these experiments examine the behavior of small amounts of plutonium when shocked by chemical high explosives.

Data recovery from the Bacchus experiment was excellent. Several complementary diagnostic tools were used for capturing data. The primary diagnostic tools were two large X-ray machines known as Cygnus, which take radiographs of the shock effects at a precise time following detonation of the chemical high explosives.

Information obtained in these experiments is used in computer models for determining the safety and effectiveness of the nuclear weapons stockpile. Bacchus is the first of three planned experiments in the Barolo series. Barolo A and B are scheduled to be conducted in the first and second quarters of fiscal year 2011.

The period of time between the Unicorn experiment and Bacchus was spent developing procedures and processes and certifying the staff members to start up and operate the current experimental area of the U1a Complex as a Category III nuclear facility. The intent is to maintain the current experimental area, and other areas as they are developed, as Category III nuclear facilities to reduce the effort and time required to field each experiment and thus, greatly reduce the cost to the Stockpile Stewardship Program.

http://nnsa.energy.gov/sites/default/files/nnsa/newsletters/10/NNSA%20NEWS%20SEPTEMBER%202010.pdf