Explosion at Japan's nuclear plant

Fukushima, Japan: Raising spectres of the Chernobyl nuclear disaster, one of Japan's quake affected nuclear reactors has suffered an explosion, which has blown the roof off the building that houses it. The risk of a nuclear meltdown in the reactor is palpable.

"We are looking into the cause and the situation and we'll make that public when we have further information," chief cabinet secretary Yukio Edano said.

Edano said an evacuation radius of 10 km (6 miles) from the stricken 40-year-old Daiichi 1 reactor plant in Fukushima prefecture was adequate.

TV footage shows vapour rising from the plant which is located 240 km (150 miles) north of Tokyo.

The blast came even as plant operator Tokyo Electric Power Co (TEPCO) tried desperately to reduce pressures in the core of the reactor.

"An unchecked rise in temperature could cause the core to essentially turn into a molten mass that could burn through the reactor vessel," a Stratfor report said before the explosion. "This may lead to a release of an unchecked amount of radiation into the containment building that surrounds the reactor."