"Seven nations--China, France, India, Pakistan, Russia, the United Kingdom, and the United States--possess nuclear weapons. In addition, North Korea tested a nuclear explosive device in 2006 and announced that it had conducted another such test in 2009, and Israel is widely thought to have nuclear weapons. As an aid to Congress in understanding nuclear weapons, nuclear proliferation, and arms control matters, this report describes which agency is responsible for research and development (R&D) of nuclear weapons (i.e., nuclear explosive devices, as distinct from the bombers and missiles that deliver them) in these nations and whether these agencies are civilian or military. It also traces the history of such agencies in the United States from 1942 to the present. This report will be updated annually, or more often as developments warrant."
CRS Report for Congress, R40439
United States. Department of State, Foreign Press Centers, Bureau of Public Affairs: http://www.fpc.state.gov/