Saturday, January 28, 2012

Japan's plutonium stockpile builds as nuke fuel cycle policy hits dead end

Japan's stockpile of plutonium had reached 45 metric tons by the end of 2010, inviting suspicion from the international community about what Japan intended to do with the fissile material. As a result, much hope has been pinned on a MOX fuel reactor being built in northern Japan to eventually consume that excess plutonium.

MOX fuel is a mix of plutonium and different uranium oxides produced as waste by conventional reactors, and the Japanese government had hopes that plants that can burn it -- like one now under construction by the firm J-Power in Oma, Aomori Prefecture -- would become the foundations of a new nuclear fuel cycle. That cycle, which would see the spent fuel from conventional nuclear plants used again in MOX-burning plants, has yet to come close to fruition. Meanwhile, reprocessing of spent fuel into plutonium has continued apace, making the entire program a symbol of policy inconsistency.

First of all, the only example of a functioning "full MOX" reactor -- one that burns MOX fuel exclusively -- has been an experimental reactor in France. Furthermore, a MOX fuel reactor core tends to have a smaller margin for error during shutdowns than a uranium-burning core. As such, MOX fuel reactor maker Hitachi-GE Nuclear Energy has said it has increased the capacity of safety valves that bleed off reactor vessel pressure during an emergency by 5 percent and developed high-efficiency control rods -- measures that will allow improvements to existing light boiling water reactors. Read More