Two more water leaks were found at the Fukushima No. 1 power plant Monday in addition to 14 found Sunday that prompted Tokyo Electric Power Co. to halt the cooling of reactor 4′s spent-fuel pool for two hours.
The leaks are believed to have been caused by freezing. The leaked water included radioactive water that had been purified, the utility said, adding that the contamination level is low.
The water temperature in the spent-fuel pool remained almost flat at 21 degrees, it said.
The Nuclear and Industrial Safety Agency instructed the utility to investigate the leaks and take preventive steps.
Tepco said Monday that its measures for dealing with the effect of cold weather on piping were insufficient and that it would replace the pipes with polyethylene ones that are wrapped with insulating materials.
Tepco said that around 40 liters of real water leaked from the pool-cooling system at reactor 4 Sunday morning, while probably 600 liters of purified water were found to have leaked from another facility. Water also leaked at other facilities. Another 30 liters leaked Monday, it said.
It is believed the water did not flow into the ocean, it said.
Temperatures in Namie, near the plant, fell below minus 8 early Sunday, Tepco said.