Power has been partially restored at Japan's Fukushima nuclear plant's fuel storage pools, allowing two out of four pools to be resupplied with fresh cooling water after some 20 hours.
The plant's operator said it was repairing a broken switchboard that might be the cause of the problem.
Tokyo Electric Power Company (TEPCO) said that pool temperatures at the plant were well within safe levels and that all four pools would remain safe for at least four days without fresh cooling water.
The utility said the reactors were unaffected and no other abnormalities were found.
The Fukushima Dai-ichi nuclear power plant was severely damaged by a 2011 earthquake and resulting tsunami, which caused fuel-storage pools to overheat and three reactor cores to melt, which allowed a leak of radioactive material.
Based on reporting by AP and the BBC