FUKUI – A reactor at the Oi nuclear power plant in Fukui Prefecture was manually shut down Saturday night due to a problem with its cooling system, operator Kansai Electric Power Co. and prefectural government officials said.
The Nuclear and Industrial Safety Agency said the problem with the plant’s No. 1 reactor posed no environmental hazard.
Reactor 1 at the Oi plant has been undergoing adjustment procedures prior to commercial operations for an unusually long period of about four months.
According to NISA and Kepco, the pressure inside the accumulator in the reactor’s emergency core cooling system temporarily fell around 10:45 p.m. Friday, setting off an alarm. The accumulator holds coolant to be injected into the reactor in an emergency.
The pressure stabilized, but the utility halted the reactor to find the cause of the problem.
The shutdown prompted Kepco to postpone applying for government permission to resume commercial operations at the reactor, sparking fears of electricity shortages this summer in the Kansai region.
The utility has asked both households and businesses in its service area to cut their power use by 15 percent between July 1 and Sept. 22. Industry sources said Kepco could seek further cuts after the Oi shutdown.