U.S. plans to conduct subcritical nuclear experiments

by Yumi Kanazaki, Staff Writer

On November 19, it was learned that the U.S. Department of Energy is planning to conduct three subcritical nuclear experiments at the Nevada Test Site by September of next year. If carried out, these subcritical experiments would mark the first such tests since August 2006. The U.S. government claims that subcritical nuclear experiments do not violate the Comprehensive Test Ban Treaty (CTBT), as they are not accompanied by nuclear explosions. However, the tests are likely to draw criticism from home and abroad on the grounds that they run counter to the international momentum for the abolition of nuclear weapons.

A spokesman at the Nevada Test Site clearly stated in an interview with the Chugoku Shimbun that the United States is considering a plan to conduct three subcritical nuclear experiments by the end of the 2010 fiscal year in the U.S.--in other words, by September 2010. However, the specific timing for conducting the tests is undecided and the spokesman said that the plan may be changed or cancelled.

According to the spokesman, the subcritical experiments, which aim to "assure the safety, security and reliability of U.S. nuclear weapons," will be overseen by the Los Alamos National Laboratory in New Mexico. The presence of age-related deterioration in the nuclear warheads will be checked by sending shock waves to a small amount of plutonium, with the help of high explosives.

If the United States proceeds with the plan, this will probably invite criticism on the grounds that the execution of these tests contradicts efforts toward nuclear non-proliferation, which have been positioned as an important issue by U.S. President Barack Obama. Such subcritical nuclear experiments might influence discussions about the ratification of the CTBT at the U.S. Senate. Some experts in the U.S. hold the view that the U.S. government could present a useful argument to persuade those opposed to ratification of the CTBT by demonstrating that the nation is able to sustain the performance of its nuclear weapons without nuclear explosions.

The Nevada Test Site, which has an underground facility for subcritical nuclear experiments, is located about 100 kilometers northwest of the city of Las Vegas. In 1992, the United States declared a moratorium on nuclear tests accompanied by nuclear explosions. The nation conducted 23 subcritical nuclear experiments between 1997 and 2006.


Subcritical nuclear experiments
Subcritical nuclear experiments are not accompanied by nuclear explosions, as the small amount of nuclear material used is designed to prevent the critical state in which a chain reaction of nuclear fission occurs. Two of the subcritical nuclear experiments conducted by the United States since 1997 were held in conjunction with the United Kingdom. Russia, too, has conducted subcritical nuclear experiments on the island of Novaya Zemlya in the Arctic zone.

(Originally published on November 20, 2009)