US conducts subcritical nuclear test
The Energy Department has confirmed the United States has carried out a subcritical nuclear experiment at an underground test site in Nevada on Thursday (local time).
The test was aimed at gathering ''scientific data that provides crucial information to maintain the safety and reliability of... nuclear weapons without having to conduct underground nuclear tests,'' the department said.
Some anti-nuclear groups are concerned that the Bush administration is trying to accelerate its efforts to develop new nuclear arms through such tests.
Anti-nuclear groups have criticised and continue to urge Washington to stop the tests, saying they are undermining the Comprehensive Test Ban Treaty on nuclear weapons.
The US argues that subcritical tests are fully consistent with the nuclear test moratorium it has maintained since 1992.
It says the tests do not violate the treaty because they do no involve a nuclear chain reaction and are necessary to ensure the safety of nuclear stockpiles.
The department said the Los Alamos National Laboratory and Britain's Atomic Weapons Establishment ''successfully'' undertook the latest experiment in an underground laboratory of horizontal tunnels about 290 metres beneath the surface.
According to the department, subcritical tests ''examine the behaviour of plutonium as it is strongly shocked by forces produced by chemical high explosives".
''The experiments are subcritical, that is, no critical mass is formed and no self-sustaining nuclear chain reaction can occur, thus, there is no nuclear explosion,'' the department said.
The test, conducted together with Britain, represented the first since May 2004 and the ninth under the administration of President George W Bush.
It was the second carried out with Britain following one in February 2002.