After nearly four years of requests from the United States and recent protests from China, Chief Cabinet Secretary Yoshihide Suga confirmed on Wednesday that Japan will return its stockpile of highly concentrated plutonium that was purchased during the 1960s and 1970s from the United States and the United Kingdom.
Japan has told the United States that it will return the weapons-grade plutonium if it receives in return lower-grade plutonium with which to continue research.
Japan purchased enough plutonium to construct 50 nuclear weapons to use for research at Tokai Village, which is over 60 miles north of Tokyo. By 2012, Japan was in possession of 331 kilograms of weapons-grade plutonium.
The plutonium is used in the Fast Critical Assembly (FCA) at the Tokai facility operated by Japan’s Atomic Energy Agency, which is designed to study fast breeder reactors. In fact it is the only critical assembly available to Japan, which may explain some of their lack of willingness to return it.
Japan has resisted repeated requests from the United States since 2010 to return the materials, using their research of fast breeder reactors as justification, but now the Japanese government has decided that continuing to refuse to return the materials could damage relationships with the United States and other nations.
Aside from the highly concentrated plutonium used in the fast critical assembly, Japan also has an estimated inventory of 44 tons of reactor-grade plutonium.
Source: The Japan Times