"Since 1945, seven nations--China, France, India, Pakistan, Russia, the United Kingdom, and the United States--have developed and currently deploy nuclear weapons. North Korea tested a low-yield nuclear explosive device in October 2006, announced that it had conducted a second nuclear test in May 2009, and announced a third test on February 12, 2013. Israel is generally thought to possess nuclear weapons, although it maintains a policy of ambiguity on this matter. This report describes the organizations controlling research and development (R&D) on nuclear weapons (i.e., nuclear explosive devices, as distinct from the bombers and missiles that carry them) in these nations, and presents a brief history of the organizations controlling nuclear weapons R&D in the United States. It discusses whether these organizations are civilian or military, though in many nations the lines between civilian and military are blurred. This information may be of use to Members of Congress and their staff interested in nuclear weapons, nuclear proliferation, and arms control matters."
CRS Report for Congress, R40439