The recent nuclear disaster in Japan has exposed two dangers facing reactors in the United States — the complete loss of electrical power and spent fuel pools that are too densely loaded.
Some of the nation’s top nuclear experts and two Central Coast lawmakers testified at a Senate hearing Tuesday in Washington, D.C., about what can be learned from the triple tragedy of a powerful earthquake, tsunamis and nuclear meltdown in Japan.
Lawmakers also warned nuclear industry officials and regulators not to get complacent. The tragedy in Japan showed that multiple disasters can overwhelm safeguards at a nuclear power plant.
“We have just got to respond in a much different way,” said Sen. Barbara Boxer, D-Calif. “We are not humble enough in the face of what Mother Nature can do.”
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Gregory Jaczko, chairman of the Nuclear Regulatory Commission, said most of the problems in Japan were caused by loss of electrical power when the plant was inundated by the tsunamis. Electricity is needed to keep pumps running that cool reactors as well as spent fuel pools.
At Diablo Canyon, each reactor has three diesel generators with seven days’ worth of fuel and enough batteries for eight hours. The plant also has gravity-fed pools that can supply additional cooling water.
James Boyd, vice chairman of the California Energy Commission, said there have also been discussions about bringing in more batteries by helicopter, if needed.
Boyd and many others who testified Tuesday said spent fuel pools are a big worry. Like most plants, Diablo Canyon’s pools are far more densely loaded with used fuel than originally designed.
More than 500 fuel assemblies have been transferred into dry casks at Diablo Canyon, but the two pools still contain some 1,000 assemblies. Dense packing is dangerous because the fuel rods are more likely to catch fire, releasing radiation, if water is lost from the pools.
At the hearing, state Sen. Sam Blakeslee, R-San Luis Obispo, and Rep. Lois Capps, D-Santa Barbara, renewed their pleas to the NRC to stop license renewal of Diablo Canyon until detailed seismic studies are done, peer reviewed and incorporated into the renewal process.
“Failure to do so is unwise and irresponsible,” Capps said. “It will feed public uncertainty about the oversight and safety of nuclear energy. And it could cost taxpayers billions of dollars to once again belatedly address issues that should have been dealt with beforehand.”
Blakeslee also said he is concerned that the NRC is not conducting any safety reviews specifically for Diablo Canyon and California’s other nuclear plant, San Onofre, in the aftermath of the earthquakes in Japan. Diablo Canyon and San Onofre are the only two plants in the nation with very high earthquake risk.
Diablo Canyon’s owner, PG&E, has asked the NRC to delay “the final processing” of the renewal application until the seismic studies are complete. However, in a separate letter to the NRC on Tuesday, the utility made it clear that it does not want any delay in the ongoing safety and environmental reviews of the renewal application.