Union of Concerned Scientists Says Nuke Plants Should Have 16 Hours of Reserve Battery Power
Center recommends 24 Hours of Battery Power
These recommendations are in response to the loss of backup power at the Fukushim Daiichi nuclear power facility in Japan. At Fukushima, a powerful earthquake knocked out primary power, and a subsequent tsunami wiped out backup diesel generators. On-site batteries depleted within eight hours, leaving workers with no power to cool the cores of three nuclear reactors. After they ran out of battery power, there was no way to cool the reactors and hydrogen explosions and serious damage resulted at three of the reactors. If U.S. nuclear power plants should lose primary and backup power — as happened in March at the Fukushima Daiichi facility in Japan — batteries are designed to kick in and prevent nuclear fuel from melting.
U.S. nuclear plants are required to maintain two backup diesel generators for each reactor.
At Fukushima, water drained from spent fuel pools and the fuel heated up, releasing intense radiation that hampered work at the site. The exposed fuel also might have triggered the explosions that seriously damaged the buildings housing reactors Units 1, 3 and 4. At the hearing, Lochbaum recommended that U.S. plant operators transfer fuel from water-cooled pools to safer, passively air-cooled storage units called dry casks. A dry cask storage unit at Fukushima, which contains more used fuel than the water pools, has remained safe and has released no radiation despite the disaster.
Wash Post, 5/14/2011)