Global Stocks of Nuclear Explosive Materials

In an exemplary exercise of what might be termed "public intelligence," the Institute for Science and International Security (ISIS) has published a new account of nuclear explosive materials around the world.
The ISIS database provides estimates of national inventories of plutonium and highly enriched uranium (as well as neptunium-237 and americium) for countries from Argentina and Armenia to Vietnam through the end of 2003. More than 50 countries were found to possess five kilograms or more of these materials. Such information is ordinarily very closely held, not only by the foreign governments themselves but also by U.S. government agencies.
"Some agencies would classify all of this stuff," observed a State Department intelligence official seated next to me at the ISIS briefing on September 7 presenting the new estimates. But of course classification renders information unavailable for public deliberation. The purpose of the ISIS publication, in contrast, is "to create a set of data that everyone can use," said ISIS President David Albright.
"We need a common language to discuss this," he said, particularly in light of the threat of diversion of nuclear materials by terrorists. "There is a lot of fissile material in the world," Albright said, noting that ISIS had estimated the production of nearly 4000 tonnes of highly enriched uranium and plutonium, enough for more than 300,000 nuclear weapons.
See "Global Stocks of Nuclear Explosive Materials," Institute for Science and International Security, published September 2005: http://www.isis-online.org/global_stocks/end2003/tableofcontents.html