One of the lesser-noted facts of the Fukushima nuclear disaster—where loss of coolant in spent-fuel pools has resulted in massive radiation releases—is that some fuel at the plant was stored in so-called dry casks, and these casks survived the March 11 earthquake and tsunami intact.
This fact is likely to result in new calls to move some spent fuel out of water pools at reactor sites in the United States—where it is packed more densely than the fuel in the stricken Japanese pools—and into outdoor dry casks, experts say.
"What will likely happen very quickly is that the [Nuclear Regulatory Commission] and utilities will arrive at a consensus that moving fuel to dry storage needs to be accelerated to get as much spent fuel out of the pools as fast as possible," says Ron Ballinger, an MIT nuclear engineer. In Japan, he says, "the dry storage casks weathered the earthquake and tsunami with zero problems."
Until now, U.S. regulators have decided that keeping fuel in pools—and even allowing the fuel to be more densely packed—is safe. Most U.S. nuclear reactors have air-cooled, dry-cask storage for some reactor waste, but generally this is only because the pools cannot fit any more. Older waste that has had a chance to cool for a few years in pools can be moved to dry casks.