The Japanese Nuclear Cycle Development Institute says that it has used radioactive materials from Russian nuclear weapons to make fuel for civilian nuclear power plants. Since 1999, the Japanese facility, working in cooperation with Russia's Research Institute for Atomic Reactors, has refined about 20kg plutonium from Russian weapons into MOX fuel. For testing purposes, the MOX fuel has been burned in a Russian built BN-600 fast reactor.
By 2020, the facility is expected to dispose of 20kg of plutonium in this fashion. The resulting MOX fuel will be burned at light water reactors in Japan and elsewhere.