Japan: Explosion at Fukushima 3 nuclear reactor, March 14, 2011 (video)

[Video Link] Above, video of the second explosion at Japan's Fukushima Daichi (No. 1) nuclear power plant since the 9.0 earthquake and subsequent tsunami devastated the country. This apparent hydrogen blast involved the plant's troubled No. 3 reactor. A similar explosion happened at the No.1 reactor at the same plant on Saturday. Both blasts tore the roof off of the affected structure, but are believed not to have damaged the reactor core.

Authorities again urged residents in a 20-kilometer radius around the plant to evacuate.

The IAEA confirms that the explosion occurred at 11:01AM local Japan time, roughly two hours prior to the time of this blog post. Here is a related overview/update from the IAEA about the status of Units 1, 2, 3 and 4 at Fukushima Daini nuclear power plant.

From Japan's Kyodo news agency:

Chief Cabinet Secretary Yukio Edano said the plant operator Tokyo Electric Power Co. confirmed that the 11:01 a.m. blast did not damage the container of the No. 3 reactor, allaying concerns that the explosion may have caused a massive release of radioactive substance. TEPCO said three workers, including its employees, were injured by the blast. All of them suffered bruises.

"According to the plant chief's assessment, the container's health has been maintained," Edano told a press conference. "The possibility is low that massive radioactive materials have spattered."

Here is a related report on the incident from Japan's NHK network which says a total of six workers were injured.

Related reading: Boing Boing Science Editor Maggie Koerth-Baker's "explainer" on how nuclear power plants work, and what is going on at the Fukushima sites.