In 2006, a National Academy of Sciences committee recommended two simple steps to prevent spent nuclear fuel from catching fire: putting old, cool fuel next to the new, hot fuel discharged from a reactor, and adding sprayers that could dispense water if the cooling water in the pool was lost. But no such action has been taken, either in the United States or in Japan — where the most deadly danger at Fukushima nuclear plant since the recent earthquake and subsequent tsunami has been the risk that uncovered spent fuel in the storage pools would catch fire, spreading radioactive material miles downwind. Nor has much of the older spent fuel been moved out of pools into safer dry casks made of steel and concrete — another possibility to reduce the risk.
Bunn, Matthew. "How We Can Reduce the Risk of Another Fukishima." Washington Post. March 24, 2011.