28 Mar (NucNet): Japan’s Nuclear Regulation Authority (NRA) has approved a 30-year plan to decommission the prototype Monju fast breeder reactor in Fukui Prefecture, southwest Japan, reports in local media said.
The Japan Atomic Energy Agency (JAEA), Monju’s operator, filed a decommissioning application with the NRA in December 2017, while a basic decommissioning plan was approved by a Japanese government commission in June 2017.
According to the Japanese daily Mainichi, the approved plan calls for dismantling the reactor in four phases, beginning with the removal of 530 spent fuel rods from the reactor core between fiscal 2018 and fiscal 2022 and ending with the demolition of the reactor building by fiscal 2047.
However, Mainichi said the plan does not define how 760 tonnes of radioactive sodium coolant will be extracted from Monju and what the final destination for the spent fuel will be.
Tokyo-based industry group Japan Atomic Industrial Forum said last year that the government has not yet specified any destination for the spent fuel. Jaif said officials will work out details of a transportation plan before the fuel is completely removed from the reactor.
Monju is a 246-MW sodium-cooled fast reactor designed to use mixed fuel rods of uranium and plutonium and to produce more fissile material than it consumes. Monju reached criticality for the first time in 1994, but it has mostly been offline since 1995 when 640 kg of liquid sodium leaked from a cooling system, causing a fire.
Monju was allowed to restart in May 2010 after JAEA carried out a review of the plant’s design, and its safety procedures, which were shown to be inadequate. However, operation was again suspended in August 2010 after a fuel handling machine was dropped into the reactor during a refuelling outage. Japan’s government decided to permanently shut down the reactor in 2016.
Decommissioning and dismantling costs are estimated at $3.2bn.
