A nuclear reactor of a power company in Japan was shut down on Saturday after problems started in its cooling system, Xinhua reported.
The No 1 reactor of the Ohi nuclear power plant in western Fukui prefecture was shut down after problems started Friday night. There was however no radiation leakage, Japan's Nuclear and Industrial Safety Agency said.
The 1,180,000-kilowatt reactor has been undergoing final adjustment procedures prior to its commercial operations.
The plant is owned by Kansai Electric Power Co.
Kansai president Makoto Yagi said: "We will make efforts to secure additional supply capacity to prevent a blackout."
The Ohi reactor is one of the 19 reactors in the country that remain active after the twin disasters of earthquake and tsunami in March.