Japan fears meltdown as systems fail at second nuclear reactor  

The Guardian has a report on developments in Japan's damaged nuclear infrastructure - Japan nuclear fears as systems fail at second reactor. More at the Washington Post.

Fears of another explosion at a Japanese nuclear plant are growing after officials said the cooling system in a second reactor had failed.

Thousands of people were evacuated on Saturday following an explosion and leak from the Fukushima Daiichi plant, 240 km (150 miles) north of Tokyo.

It was believed the first explosion had been contained and disaster avoided.

But on Sunday the plant operator, Tokyo Electric Power (TEPCO) said radiation levels around the Fukushima Daiichi plant had risen above the safety limit and said the cooling system in the number three reactor had failed.

It was preparing to vent steam to relieve pressure in the reactor and the government had warned of a rise in radiation during the procedure.

Fears of a nuclear fallout were first raised when a massive explosion rocked the Fukushima Daiichi atomic power plant following damage to the number one reactor in Friday's earthquake.

A pall of grey-white smoke rose over the plant, operated by Tokyo Electric Power, and it was reported that four workers had been injured.

Government officials revealed plans to distribute iodine tablets – a treatment for radiation poisoning – to locals while a 20km exclusion zone was set up round the plant.

Residents outside the zone were urged to stay inside, close doors and windows and turn off air conditioning. Scientists had detected eight times the normal radiation levels outside the facility and 1,000 times normal levels inside the affected unit's control room.

Japan's prime minister, Naoto Kan, declared a state of emergency at the crippled unit and at its sister plant, the Fukushima Daini, as engineers tried frantically to determine whether the reactor had gone into meltdown.