Japan had 48 tons of plutonium as of the end of 2014 and sent 331 kilograms of plutonium to the United States earlier this year. Under the US-Japan reprocessing program (dating from 1988 and to be reviewed in 2018) plutonium extracted from used nuclear fuel is recycled to make plutonium-uranium mixed oxide fuel usable at nuclear power plants. Japan has licensed companies in foreign countries such as Britain and France to produce the so-called MOX fuel. But the plutonium recycling effort has faltered because most of Japan’s nuclear plants have suspended operations due to public safety concerns since the meltdowns at the Fukushima No. 1 plant following the giant earthquake and tsunami in 2011. In 2016, the senior director for arms control and nonproliferation at the National Security Council said the United States would back a change to Japan’s nuclear fuel reprocessing program because Japan has large plutonium stockpiles, which "don’t have a dedicated pathway to use and disposition” and can be used to make nuclear weapons.