Nuclear reactor in Fukui Pref. halted over glitch

FUKUI, Japan, July 17 Kyodo - A reactor at Kansai Electric Power Co.'s Oi nuclear power plant in Fukui Prefecture has been halted due to a problem with its cooling system and an investigation will be conducted to determine the cause of the glitch, prefectural government officials and the plant's operator said Saturday.
The government's Nuclear and Industrial Safety Agency said the problem with the No. 1 reactor at the plant will not have an adverse effect on the environment. The reactor has been undergoing adjustment procedures prior to commercial operations for an unusually long period of around four months.
According to the agency and Kansai Electric, 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 has stabilized since, but the utility began reducing the power of the reactor at 1 p.m. Saturday and halted it after 8:50 p.m. to determine what caused the problem.
A company official said there is a possibility that nitrogen leaked from a valve of one of four accumulators located inside the reactor's containment vessel, leading to the reduction in pressure.
The trouble prompted Kansai Electric to postpone applying for government permission for resuming the reactor's commercial operations, stoking concern about possible electricity shortages in the Kansai region during the peak summer season.
A senior official at the prefectural government suggested that the suspension of the troubled reactor could last a long time.
''The safety of the reactor must be confirmed under new safety standards that take into consideration the Fukushima Daiichi accident,'' the official said, referring to the ongoing crisis at the nuclear complex in the northeastern region that has been crippled since the March 11 earthquake and tsunami.
The shutdown of the reactor at the Oi plant left in operation only 18 of the 54 reactors in the country that are run by utilities.
If there are further delays in resuming reactors that are currently shut down, all of the reactors in the country could be shut down by April as Japanese law stipulates that nuclear reactors must undergo regular checks after 13 months of operation.
Utilities are facing difficulties in restarting reactors after regular checks because they are unable to secure approval from local municipalities amid worries about safety and they have to pass new stricter safety standards imposed after the nuclear crisis.
Kansai Electric President Makoto Yagi issued a statement, saying, ''We will make utmost efforts to secure additional supply capacity to prevent a situation that leads to a blackout.''
The utility has asked customers, both households and businesses, in its service area in western Japan to reduce power consumption by 15 percent between July 1 and Sept. 22. Industry sources said Kansai Electric could seek further power saving due to the problem at the Oi plant.
The utility has secured the right to receive up to 350,000 kilowatts of electricity from Chugoku Electric Power Co. in the event that an electricity shortage occurs during the period from Saturday to July 31, and the company is in negotiations to receive support in August as well.
The Oi plant's No. 1 unit was halted last December for regular checks and resumed operation in March for adjustment procedures prior to a restart of commercial operations, originally scheduled for April.
The reactor operated at near full capacity for much of the adjustment phase, including at the time the accident occurred Friday night.