Japan’s Kansai Electric Power Company says, it plans to manually shut down today the Number One reactor at its Ohi power plant because of a technical problem, but no radiation leakage had occurred. Kansai officials said the reactor, located about 350 kilometers west of Tokyo, will be closed for checks after pressure in a tank containing boric acid water fell briefly last night for unknown reasons. The pressure has since come back up to normal.

The shutdown will worsen a power shortage caused by the meltdown of the Tokyo Electric Power Company’s Fukushima Number One plant, hit by the March 11 earthquake and tsunami.