TOKYO — Japan’s Nuclear Regulation Authority on Wednesday approved a plan to decommission the trouble-plagued Monju prototype fast-breeder nuclear reactor over the next 30 years.The move paves way for the Japan Atomic Energy Agency to take on the task of scrapping the reactor in Fukui Prefecture in central Japan, although a number of problems remain, including how to remove its sodium coolant and where to take the spent nuclear fuel.
The government originally hoped the Monju reactor would serve as a linchpin for nuclear fuel recycling efforts as it was designed to produce more plutonium than it consumes while generating electricity.
But the reactor has barely operated over the past two decades despite the state investing 1 trillion yen ($9.46 billion) as it experienced a slew of problems, including a leakage of sodium coolant in 1995 and a very high number of equipment inspection failures in 2012. The government decided to scrap the reactor in 2016.
The approved plan calls for dismantling the reactor in four phases, beginning with the removal of 530 spent fuel rods from the reactor core and other places between fiscal 2018 and 2022 and ending with the demolition of the reactor building by fiscal 2047.
The plan does not outline in detail how some 760 tons of radioactive sodium coolant, which demands careful handling as the chemical bursts into flames on contact with air or water, will be extracted.
Where to take the spent fuel also remains undecided, and it could possibly be kept within the facility for an extensive period, as a reprocessing plant within Japan that was scheduled to operate has been scrapped, forcing the agency to look for another handler abroad.
Of the 375 billion yen cost estimated by the state, 150 billion yen will go on the actual scrapping and the rest on managing related facilities.