Japan sends 331 kg of weapons grade plutonium to U.S.: GreenpeaceTOKYO (Reuters) - A ship loaded with weapons-grade plutonium left Japan for the United States on Tuesday in what is the largest such shipment of the highly dangerous material since 1992, the environmental group Greenpeace said. The 331 kg (730 lb) of plutonium, enough to make about 50 nuclear weapons, was taken from a nuclear research center in the port town of Tokai Mura, and left on a British sh
