NNSA conducted Pollux, its 27th subcritical explosion test, at its Nevada National Security Site near Las Vegas. The most recent, previous subcritical test in this series, code-named Bartolo B, took place February 2, 2011, said an NNSA press release, further explaining that:
Subcritical experiments examine the behavior of plutonium as it is strongly shocked by forces produced by chemical high explosives. Subcritical experiments produce essential scientific data and technical information used to help maintain the safety and effectiveness of the nuclear weapons stockpile. 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.
Perhaps the first formal objection to the NNSA nuclear weapons test came from the Japan Council Against A & H Bombs (Gensuikyo), which sent a note of protest directly to President Obama, saying:
"Whether it involves an explosion or not, nuclear testing runs counter to the spirit of the Comprehensive Test Ban Treaty (CTBT) and the agreement of achieving the "peace and security of a world without nuclear weapons" reached by the 2010 NPT [Nuclear Proliferation Treaty] Review Conference.
"Your administration seeks non-proliferation of nuclear weapons. But your position of urging most others to renounce nuclear weapons, while continuing your own nuclear tests, does not stand by reason nor is it supported by the world public."-"-
""-In the name of the A-bomb survivors of Hiroshima and Nagasaki and on behalf of the people of Japan, the only A-bombed country, we call on you to cancel all plans of nuclear testing and make a sincere effort to achieve a total ban on nuclear weapons and a world without nuclear weapons.""-
The White House has apparently not yet responded.
On December 5, Gensuikyo wrote the Government of North Korea, urging it to cancel its planned launch of a satellite rocket. North Korea conducted the most recent known nuclear test explosion on May 5, 2009.