"WASHINGTON -- One day after deadly tornadoes knocked out power to nuclear reactors in Alabama, the head of the U.S. nuclear safety regulator expressed concern whether backup batteries at sites across the United States have the staying power in a prolonged emergency.
The commission on Thursday was examining whether the 104 U.S. nuclear plants have enough emergency power in place to ensure that safety systems can keep running in extreme blackouts, like when an earthquake and tsunami shut down power to the Fukushima plant in Japan in March.
Senior staff at the Nuclear Regulatory Commission explained that plants have a series of strategies including diesel generators, emergency fuel supplies, back-up batteries and battery rechargers to keep plants going when power gets knocked out.
But commissioners questioned whether enough attention was being paid to the lifespan of batteries used in worst-case scenarios, which are designed to last at least four hours to give plants enough time to get longer-lasting back-ups in place.
'We have lots of examples where it takes longer than four hours to restore offsite power,' said NRC Chairman Gregory Jaczko."