Blast damages roof of Japan nuclear reactor, steam rising

TOKYO - A fresh explosion at Japan's quake-stricken nuclear power plant damaged the roof above its overheating No.2 reactor on Tuesday and steam is rising from the complex, Jiji news agency said.
Authorities at the Fukushima Daiichi complex, damaged in Friday's massive earthquake and tsunami, are trying to prevent meltdowns in all three of the plant's nuclear reactors.
Twice before, there have been explosions which have ripped off some roofing from the plant, but these had not damaged the reactor vessels, authorities have said.