SSS 2011-03-14（在线收听）

This is Scientific American's 60-Second Science. I'm Steve Mirsky. This will just take a minute.

"The type of accident that is occurring in Japan is known as the station blackout: loss of off-site AC power—power lines are down—and then a subsequent failure of emergency power on-site, the diesel generators. The station blackout has been one of the great concerns for decades."

Physicist Ken Bergeron, speaking on March 12 during a press briefing. He worked on nuclear reactor accident analysis at Sandia National Laboratories.

"The probability is hard to calculate primarily because of the possibility of what are called common-cause accidents, where the loss of off-site power and of on-site power are caused by the same thing. In this case the earthquake and tsunami. We're hoping that all of the barriers to release of radioactivity will not fail. So far the first barrier, which is the fuel cladding, has apparently failed, because they are detecting cesium. We now have to hope that the subsequent layers, including primarily the containment building, will succeed in preventing release of major amounts of radioactivity."

Thanks for the minute. For Scientific American's 60-Second Science, I'm Steve Mirsky.

For more from Bergeron, see my article on the SciAm Web site "Nuclear Experts Explain Worst-Case Scenario at Fukushima Power Plant"