TOKYO — Japan's second-largest nuclear operator said Saturday that it was manually shutting down a reactor in central Japan after a technical malfunction.
No radiation had leaked from the No. 1 Reactor at the Oi Nuclear Power Plant, on the Japan Sea coast, about 250 miles west of Tokyo, said Yoshihiko Kondo, a spokesman for the plant's operator, Kansai Electric Power.
Mr. Kondo said that a loss of pressure had been detected late Friday in an accumulator tank needed to cool the reactor core in an emergency, forcing the utility to shut down the reactor. Workers will begin the shutdown at 1 p.m. Saturday in Japan, and shutdown will be complete by 9 p.m., he said.
The shutdown at Oi just four months after the devastating accident at the Fukushima Daiichi Nuclear Power Plant comes as a blow to an industry struggling to regain public confidence. It also worsens an electricity shortage that has forced several utilities in Japan to require companies to reduce their use by at least 15 percent.
Only 19 of Japan's 54 nuclear reactors are operating, because units shut down for regular maintenance have not been given permission by local governments to restart after the disaster at Fukushima, operated by Japan's largest nuclear operator, Tokyo Electric Power. In the meantime, more reactors have been closing for scheduled maintenance, reducing the number in service across the country.
The 1.17-million-kilowatt Oi No. 1 Reactor, built in 1979, had been in the last stages of a trial run at full output after undergoing scheduled maintenance this year. At Kansai Electric, only four of its 11 reactors are now operating.
