Japan's Kansai Electric Power Co. said on Saturday it planned to manually shut down the No.1 reactor at its Ohi nuclear power plant in western Japan's Fukui Prefecture due to technical glitches with its cooling system, Jiji Press reported.

No radiation leakage had occurred and the problem will not have adverse effects on the environment, according to Japan's Nuclear and Industrial Safety Agency.

The pressure inside the accumulator in the reactor's emergency core cooling system temporarily fell on Friday night, setting off an alarm. The accumulator holds coolant to be injected into the reactor in an emergency, Kyodo News said.

The pressure has stabilized since, but the utility will halt the reactor Saturday night to find out what caused the problem.

The reactor has been undergoing final adjustment procedures prior to commercial operations for an unusually long period of about four months. The 1,180,000-kilowatt reactor is equivalent to around 4 percent of the total power output of Kansai Electric.