NRC: Post Fukushima evaluation shows US fuel pools safe
BRATTLEBORO — The Nuclear Regulatory Commission said Monday that spent fuel pools like the one at the Vermont Yankee nuclear power plant can withstand severe earthquakes without breaching.
The draft report from the NRC’s Office of Nuclear Regulatory Research is one of the post-Fukushima evaluations the NRC has ordered for the American nuclear industry.
“It will be used to help inform a future commission decision on whether spent fuel should be moved into dry cask storage more quickly,” said Neil Sheehan, a spokesman for the NRC’s Region 1 office.
Sheehan said that the study put the odds of a serious accident resulting from an earthquake at “one in 10 million.”
In March 2011, the spent fuel pools at several nuclear power plants in Japan survived a major earthquake, but it was the resulting tsunami that created the havoc and near disaster, including the all-important loss of off-site electric power.
“Our detailed analysis showed that even a very strong earthquake has a low probability of damaging the pool studied to the point of losing water,” said Brian Sheron, director of the NRC’s Office of Nuclear Regulatory Research, via a prepared statement.
According to Sheron’s summary, the study including both a ‘full’ spent fuel pool, as is the case at Vermont Yankee, and another with less fuel and more spacing.
Vermont Yankee’s spent fuel pool has been full for several years, with Entergy Nuclear now transferring the oldest fuel in the spent fuel pool into concrete and steel casks, for storage on site.
Even nuclear critics believe that the so-called dry cask storage is safer than the used fuel kept in a giant, water-filled tank.
But two prominent nuclear critics in Vermont both said the report ignored the obvious.
“The NRC is basically saying that the accident at Fukushima did not and cannot happen and should be excluded from any rational discussion. It was the likelihood of a fuel pool breach in Daiichi Unit 4 that caused the U.S. to withdraw all U.S. nationals out to 50 miles,” said Arnie Gundersen, a nuclear engineer with the Burlington consulting group Fairewinds Associates.
“The Daiichi 4 pool was damaged, and later repaired. It was a very close call,” he said.
“Sooner or later, in any foolproof system, the fools are going to exceed the proofs,” he added.
Raymond Shadis, senior technical advisor for the New England Coalition, an anti-nuclear group, said the NRC report should also evaluate truck bomb blast wave, or aircraft impact.
He said that the NRC’s own structural consultant, Robert P. Kennedy, said in another report that the bottom of the Vermont Yankee spent fuel pool could drop out, “leaving 2 million pounds of spent fuel with no shielding.”
“It would instantly become the world’s largest outdoor sterilizer, with a range of over half a mile,” Shadis said.
A seismic event may not be the most likely threat to Yankee’s spent fuel pool, Shadis noted.
He said by the NRC’s own technical calculations, that a spent fuel cask drop from just four feet above the pool bottom would result in the cask going right through it, effectively punching a hole the diameter of the cask — about 11 feet.
“Try replenishing that coolant loss with a fire hose,” he said.
About five years ago, when Entergy Nuclear was first shifting spent fuel into the concrete casks, there was a near miss, when the brakes on the crane lifting the loaded cask almost didn’t stop.
“I would suggest that playing the probabilities card should be way low on NRC’s game plan,” he added.
The NRC is seeking public comment on its spent fuel pool study. The public and interested groups can comment on the study using Docket ID NRC-2013-0136 on the regulations.gov website, and for 30 days following the publication of a notice in the Federal Register, expected shortly.
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