World Plutonium Inventories
Compiled by Sarah Ong
The Natural Resources Defense Council produced the most recent compilation of data on world plutonium inventories in 1999. According to “World Plutonium Inventories 1999,” the first-ever gram amounts of plutonium were provided to Manhattan Project scientists in 1944. Since World War II, more than 1,200 metric tons of plutonium have been produced in nuclear reactors. Of those 1,200 metric tons, approximately 260 are weapon-grade plutonium containing less than 7 percent Plutonium-240, an isotope with a high spontaneous fission rate. Despite its high Plutonium-240 content, nuclear weapons can be made with reactor-grade plutonium.
At an average of three kilograms per warhead, the world’s approximately 260 tons of weapon-grade plutonium produced since 1945 would be enough for more than 85,000 warheads.
While the inventory of weapon-grade plutonium is unlikely to increase, the operation of the world’s 433 nuclear power reactors means that the amount of reactor-grade plutonium will continue to grow. Most of this civilian plutonium remains in spent fuel rods removed from reactors. However, more than 200 tons of civil plutonium have been separated, just as weapon-grade plutonium is obtained by chemically dividing it from irradiated fuel.
Eighteen to twenty countries have nuclear reactors and spent fuel. Five countries are engaged in commercial reprocessing: France, Britain, Russia, India, and Japan. The U.S. plutonium inventory is the one we know the most about. Of its 85 tons, about 64 are used in current weapons or stored as intact weapon pits. The remaining 21 tons are stored as solutions, scrap, and waste material at Rocky Flats and other Energy Department sites.