A huge pall of smoke was seen coming from the plant at Fukushima and several workers were injured.
Japanese officials fear a meltdown at one of the plant's reactors after radioactive material was detected outside it.
A huge relief operation is under way after the 8.9-magnitude earthquake and tsunami, which killed more than 600.
Hundreds more people are missing and it is feared about 1,300 may have died. Full Story »