Japan's biggest news service - Nikkei - reports:
An explosion hit the Daiichi No. 3 nuclear plant in Fukushima Monday.
Here is footage:
And here is a before and after photo of number 3 from Japanese television station NHK:
AP/Huffington Post reports:
Japan's chief cabinet secretary says a hydrogen explosion has occurred at Unit 3 of Japan's stricken Fukushima Dai-ichi nuclear plant. The blast was similar to an earlier one at a different unit of the facility.
Yukio Edano says people within a 12-mile (20-kilometer) radius were ordered inside following Monday's. AP journalists felt the explosion 30 miles (50 kilometers) away.
This looks worse than yesterday's explosion at the number 1 reactor.
BBC points out that a meltdown at number 3 could be more serious than number 1, because number 3 uses plutonium as well as uranium:
The plant’s operator says pressure is rising inside reactor No. 3 after it lost its emergency cooling system.
A similar problem led to a blast at the plant’s No. 1 reactor on Saturday. …
But the BBC’s Chris Hogg in Tokyo says the second reactor is a different type which uses MOX (plutonium plus uranium) fuel and the consequences of a problem there are potentially more severe.