Power failure hits Fukushima spent fuel ponds

A power failure at Japan's tsunami-hit Fukushima nuclear plant has affected cooling systems for spent fuel ponds.

A statement from operator Tepco said the cause of the power failure, which began at 18:57 on Monday (09:57 GMT), was still being assessed.

The outage had hit ponds at reactors 1, 3 and 4, it said, but cooling to the reactors themselves was not affected.

There was no immediate danger as it would take four days for the hottest pool to hit safety limits, Tepco said.

"We are trying to restore power by then," Tokyo Electric Power Company (Tepco) spokesman Kenichi Tanabe said.

The temperature in the hottest fuel pond, at Unit 4, was 30.5 degrees Celsius on Tuesday morning, Tepco said, well below the safety limit of 65 degrees.

The two ponds in Units 1 and 3 had lower temperatures and would take even longer to reach the safety limit, the spokesman said.

Another common storage pool was also affected, Japan's NHK reported.