A fire broke out at a Japanese nuclear plant that has been closed since it was damaged by an earthquake in July.
The plant suffered damage in July's strong earthquake
The fire at the Kashiwazaki-Kariwa plant in Niigata prefecture was sparked by a fault in a cooler on the roof of the plant, a spokesman said.
Workers extinguished the flames and there was no danger of a radioactive leak, the spokesman said.
The plant - Japan's largest - has been closed since the area was struck by a magnitude 6.8 earthquake in July.
Shogo Fukuda, a spokesman for Tokyo Electric Power Company, which owns the plant, said that no-one was injured by the fire.
Experts were assessing the extent of the damage and the cause of the fire, he said.
The plant suffered some 50 malfunctions in the July quake, which also left 11 people dead and hundreds injured in the surrounding area.
A team from the UN's nuclear watchdog, the International Atomic Energy Agency, was called in after it emerged that leakages of radioactive material had been much bigger than initially estimated.
But in a report released last month, the team found that the damage was not as extensive as previously thought.
It said that the power station had operated safely both during and after the quake, but that further investigations were needed in case of hidden damage.
The closure of the plant triggered concern about power shortages. It is not yet clear when it will reopen.
Japan is heavily reliant on nuclear power, but the safety of its installations has come under the spotlight in recent years after a string of accidents and mishaps.