The operator of the crippled Japanese nuclear plant in Fukushima has confirmed that power outages occurred at two reactors last night.
But Tokyo Electric Power Co said it was able to continue the cooling process to bring them under control.
TEPCO said it was investigating the power outages at its No 1 and No 2 reactors in the Daiichi plant in Fukushima, which was badly damaged by the devastating March earthquake and tsunami.
The company is also considering dumping low-level radioactive water into the sea from another nearby plant slightly damaged by the March disasters.
A TEPCO spokesman said it may pump into the ocean about 3,000 tonnes of sea water that washed over the Daini plant after the tsunami.
It is about 10km from the Daiichi plant, where TEPCO is still battling to bring under control the worst nuclear disaster since Chernobyl.
It wants to dump the water from the Daini plant, which is in cold shutdown following the earthquake, to prevent further corrosion of equipment, although there is no immediate need to do so.