" #Japan welcomed the opening of the Nuclear Security Summit with the pledge that it agreed to transfer to the U.S. a (relatively small) part of its #nuclear material: more than 700 pounds of weapons-grade #plutonium and a large quantity of highly enriched uranium, a decades-old research stockpile allegedly of American and British origin, said to be large enough 'to build dozens of nuclear weapons' " https://en.wikipedia.org/wiki/2014_Nuclear_Security_Summit#Japanese_turnover_of_nuclear_material