Fukushima warning: US has 'utterly failed' to address risk of spent fuel
Nuclear experts told Congress Wednesday that spent-fuel pools at US nuclear power plants are fuller than safety suggests they should be. They say the entire US spent-fuel policy should be overhauled in light of the nuclear crisis at Japan's Fukushima plant.
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The risks posed by spent fuel held in such pools are hardly new or unknown. A 2006 study by the National Academy of Sciences (NAS) warned Congress and the Nuclear Regulatory Commission (NRC) that spent fuel pools were vulnerable to terrorist attack, with some nuclear plant designs more than others. With water gone from the pools, the spent fuel could easily catch fire and see "the release of large quantities of radioactive materials to the environment," the study found.Skip to next paragraph
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The NAS report found that another method of storing spent fuel, called "dry cask" storage, did not require on complex power systems. Dry-cask storage involves putting older spent fuel into concrete- and steel-lined cylinders to allow natural air circulation for cooling. Dividing up spent fuel among a large number of such cylinders also makes "it more difficult to attack a large amount of spent fuel at one time" and also reduces "the consequences of such attacks," the report found.
Echoes of that report could be heard in Congress Wednesday, with several experts testifying that finding a new way to deal with spent fuel was a key takeaway from Fukushima.
For instance, the Fukushima General Electric Mark 1 Boiling Water Reactor design, which has a spent-fuel pool near the top of the building where it's easy for loading cranes to access, is one of the most vulnerable reactor designs, some experts say. At least 28 of America's 104 reactors are of that type.
The Fukushima problems of spent-fuel pools located on the same site with the reactors "will undoubtedly lead to a reevaluation of spent nuclear fuel management strategy," said Professor Moniz.
Protection akin to a 'Sears storage shed'
David Lochbaum, a nuclear engineer who spent years working in power plants with the same design as the Fukushima plant, told the Senate Energy and Water Development Appropriations subcommittee today that spent fuel was a huge risk.
While nuclear fuel in the reactor is carefully safeguarded with heavy shielding and multiple redundant cooling systems, that all changes once the still highly radioactive fuel is no longer productive, he said.
"Irradiated fuel sits in temporary spent-fuel pools with almost no protection," he said. "For unfathomable reasons, irradiated fuel is considered benign after it is taken out of the reactor core" even though it will be many years before a final repository can be agreed upon and built.
Today, many US reactor operators' spent-fuel management strategy is "to nearly fill the spent-fuel pools to capacity, and then to transfer fuel into dry-cask storage to provide space for the new fuel discharged from the reactor core," Dr. Lochbaum said at the hearing. But the result is that spent-fuel pools are kept nearly full of highly radioactive fuel, "maintaining the risk at about as high a level as possible."
At many reactor sites today, there is nearly 10 times as much irradiated fuel in the spent fuel pools as in the reactor cores, Lochbaum said. Yet those pools "are not cooled by an array of highly reliable emergency-cooling systems capable of being powered from the grid, diesel generators, or batteries. Instead, the pools are cooled by one regular system sometimes backed up by an alternate makeup system."