Bolstering the safety, security of U.S. nuclear weapons

To improve the safety and security of nuclear weapons, specialists must weigh the risks and benefits of making intrinsic changes to the warheads (possibly degrading their performance) or pursuing external changes such as better access controls, according to experts at a workshop co-sponsored by the American Academy for the Advancement of Science (AAAS) and the Union of Concerned Scientists (UCS).

An AAAS release reports that while improvements such as use of shock- and fire-resistant chemical explosives in the warheads could further decrease the risk of an accidental nuclear detonation or dispersal of plutonium, most of the experts at the workshop were not greatly concerned about the safety level of the current U.S. nuclear arsenal. There was more agreement that the security of the weapons — preventing them from falling into the wrong hands — is a “substantial issue” that deserves more attention.

The experts disagreed, however, on whether some intrinsic changes to the warheads — such as use of self-destruct technologies — were practical. It should be assumed, some suggested, that any stolen weapon can be used to cause a nuclear explosion. Others felt that detonating a stolen weapon would be difficult, given such features as permissive action links (PALs) and arming sequences. Still others held that intrinsic features could add a valuable additional layer of security, reducing the probability and consequences of nuclear use if a weapon was stolen by a terrorist.

A new report summarizes the workshop, which was convened by the AAAS Center for Science, Technology and Security Policy (CSTSP) and the UCS on 12 December 2012. The workshop was conducted on an unclassified basis, under the Chatham House Rule, which encourages a frank exchange of ideas by assuring that participants will not be identified or quoted. Participants included active and retired scientists and engineers from Los Alamos National Laboratory, Lawrence Livermore National Laboratory, and Sandia National Laboratory; government representatives, including those from the (National Nuclear Security Administration (NNSA), the Department of Defense, and the State Department; independent scientists who are members of the JASON group that advises the government on nuclear weapons and other security issues; and experts from academia and nongovernmental organizations.

The release notes that NNSA is seeking to strengthen nuclear weapon safety and security, in particular by adding features to warheads and bombs as part of life-extension programs for these weapons.