A power cut has left the crippled Fukushima nuclear power plant in Japan without a fresh supply of cooling water to three of its seven fuel pools.

The outage happened on Monday night and is believed to have been caused by a broken switchboard.

Kenichi Tanabe, spokesman for plant operator TEPCO, said the temperatures of all fuel pools had risen by 0.3-0.4 degrees Celsius every hour but were well below the safety limit of 65 degrees.

Masayuki Ono, acting head of TEPCO’s nuclear power and facilities section, told a news conference this morning: “We are prioritising recovering power and restarting operations. But if it takes a long time we can pour cooling water whenever necessary so that the worst case scenario can be avoided.”