An evolving U.S. national policy aims to create a system of nuclear forensics, in which scientific analysis could quickly identify the source of a nuclear attack or attempted attack.
An independent group of nuclear weapons experts said Monday that substantial work remained to be done on a new generation of warheads in order to show, short of underground testing, that the bombs would be reliable.
Amid growing concern that nuclear weapons labs are vulnerable to a terrorist attack, senior Energy Department officials are seriously considering major steps to improve security ? including the removal of plutonium and highly enriched uranium from Lawrence Livermore National Laboratory and other weapons sites.
The United States has regained the capability to make nuclear weapons for the first time in 14 years and has restarted production of plutonium parts for bombs.