U.S. nuclear plants use the same sort of pools to cool spent nuclear-fuel rods as the ones now in danger of spewing radiation at Japan's Fukushima Daiichi plant, only the U.S. pools hold much more nuclear material. That's raising the question of whether more spent fuel should be taken out of the pools at U.S. power plants to reduce risks.
The Japanese plant's pools are far from capacity, but still contain an enormous amount of radioactivity, Lyman said. A typical U.S. nuclear plant would have about 10 times as much fuel in its pools, he said.