Tokyo Electric Power Co. said Friday it will suspend operations at the only running reactor of the six-reactor Fukushima No. 1 nuclear plant in Fukushima Prefecture, possibly from Monday, to investigate a suspected radioactive water leak.
The utility said it will take necessary steps Sunday and stop the No. 6 reactor.
Operations at five of the plant's six reactors have already been halted due to defects and regular inspections.
The suspension of operations at the last reactor may have a significant impact on the power supply in its service areas, though the utility said it will have other power plants cover the loss while expecting winter power demand to peak in January and February.
The utility suspects the presence of a water leak near a valve attached to a pipe inside the reactor containment vessel.
Up to some 750 liters of water have been draining away every hour and the amount has been gradually increasing, but there is no radiation leak outside of the plant and little immediate impact on the safety operations of the reactor, it claimed.