Japanese earthquake causes nuclear emergency - Register

The magnitude 8.9 or 8.8 earthquake that struck northeast Japan at 2:46pm local time has forced the evacuation of thousands from a 3-kilometer radius of a nuclear power plant following a failure in its cooling system, leading to the threat of a fuel-rod meltdown that has yet to be fully mitigated.

According to Japan's Juji Press, the government declared a "nuclear emergency" after emergency diesel backup systems ceased functioning at the Tokyo Electric Power company's Fukushima No. 1 plant in Fukushima Prefecture. The same report indicated the government's concerns at the time that the plant "may not be able to have sufficient reactor cooling functions."

According to an AFP report, the International Atomic Energy Agency's Incident and Emergency Centre has said that they were informed by the Japanese Ministry of Economy, Trade and Industry (METI) that "The four Japanese nuclear power plants closest to the quake have been safely shut down."

METI did not specifically mention which four plants those were, but a later Juji Press report said that in the Fukushima No. 1 plant's No.2 reactor, which had been shut down, water levels had dropped, "posing a threat of a radiation leak," and that the local governement had urged residents within a 2-kilometer radius to evacuate immediately.

A third Juji Press report extended that evacuation radius to 3 kilometers, and noted that Yukio Edano, Japan's Chief Cabinet Secretary – a position that includes press-secretary duties – had urged the 5,862 affected residents to remain calm.

The government also instructed the 45,345 residents within a 10-kilometer radius of the plant to remain in their homes, despite the fact that no radiaton leak had yet been detected.

According to The New York Times, near midnight Friday Japan time, Japanese Trade Ministry officials told Jiji Press that the cooling system was to be reactivated and "should resume normal operations." The Reg however, was unable to find a second source for that report, nor is there any mention of it on the Jiji Press website.

According to Reuters, a spokesman for the World Nuclear Association – a nuclear industry trade group – told them that "We understand this situation is under control," after a battery-powered backup system was brough online and began pumping cooling water back into the affected reactor.

A source familiar with battery-power backup cooling systems, however, told the NYT that such systems typically have enough juice for only about four hours of operation. Should a consistent source of power not be restored by that point, the cooling water would boil away, and a fuel-rod meltdown would likely occur.

In perhaps the oddest detail in this still-developing story, the NYT also reported that "United States Air Force planes based in Japan delivered emergency coolant to the plant, Secretary of State Hillary Rodham Clinton said." ®