“There has not been any radiation leakage or environmental problems. We are checking the cause of the trouble,” the utility spokesman said.
The 500 megawatt reactor is one of only nine that continues to operate in Japan and was due to be shut down for maintenance on Dec. 18.
According to the utility company, the reactor had not affected pressure inside the reactor vessel or the operation of the unit.
The spokesman said a valve connected to the reactor’s pressurizer, which maintains pressure inside the reactor vessel to prevent water from boiling, was leaking more amounts of water than normal, leading the utility to decide to shut the reactor. It was confirmed that 30 liters leaked per hour.
Last month, a nuclear reactor at the Genkai nuclear power plant in southern Japan was restarted after it automatically shut down because of a cooling system problem.