Further study of Vermont Yankee fuel casks proposed
"As Shakespeare would say, 'It's Much Ado About Nothing,'" Krishna Singh, president of Holtec International, told officials from the Nuclear Regulatory Commission last week. Singh said the design change that Holtec adopted for its Hi-Storm multi-use canisters was very minor, and didn't require approval from the Nuclear Regulatory Commission. He said there were "no real technical reasons" for the enforcement action and he said the company believes the changes should be "considered a minor violation if a violation at all."
The NRC officials were non-committal during a meeting at their headquarters last week and said a decision on Holtec's arguments would take up to 60 days. The NRC has not made a final determination on any enforcement action, said Michael Layton, division director of spent fuel management for the NRC. "I encourage you to be candid," he told Singh, saying the NRC had uncovered two apparent violations.
Singh said there was no risk to the public health and safety, and he sharply criticized social media criticisms of the Holtec canisters. "This has been taken to heart," Singh said, and had triggered a "stem to stern" review of Holtec's review policies. The prime concern centers on whether the change has compromised the cask's ability to allow the cooling of the nuclear fuel, since the casks are expected to hold the highly radioactive fuel for at least 100 years, if not longer. But Singh said an analysis of the thermal loads showed that "all regulatory limits are met" with the new design. Only a small percentage of all the pins in the cask were faulty, he said, less than 1 percent. Singh said the additional stainless steel pins at the bottom of the large canister would only help to cool the nuclear fuel.
Loose pins were discovered in a Holtec canister at the San Onfre Nuclear Generating Station in southern California last year, halting the transfer of the highly radioactive fuel from a spent fuel pool to the air and gas-cooled canisters.
The same design canisters were being used at the Vermont Yankee nuclear power plant in Vernon, and last year Entergy Nuclear halted the transfer of fuel using the canisters to inspect the Holtec canisters it had. No problems were discovered in the canisters at Vermont Yankee, but the already loaded canisters could not be easily inspected.
Layton, who led the NRC inspection team, said it was possible the NRC would require additional canister inspections. Layton said he did not believe the Holtec design problems represented an "imminent safety threat, but it may warrant additional inspections."
Raymond Shadis, a technical advisor to the New England Coalition, was among many anti-nuclear activists from California who questioned the safety of the Holtec system. "Holtec would pass off quality control to supplier/manufacturers, but the buck stops with company assembling the canisters. Many small errors can equal a determinate one, so formalities, such as reporting and regulator review must be meticulously observed," Shadis said. He said there should also be an analysis of the impact of a transportation accident involving the multi-purpose canisters.
Singh himself admitted that the company had poor oversight of the manufacturing of the canister components. He said the company had changed its oversight of the manufacturing process, and now had the canisters made adjacent to its Camden, N.J., headquarters, instead of in Pittsburgh. He said the manufacture of the shims or pins had been done "a little too roughly." He said the review of manufacturing process had been "an eye-opener."
"Manufacturing can have insidious problems," he said, and as a result was now requiring his engineers to learn how to weld, to better oversee the manufacture.
"It will never happen again," he said.
Contact Susan Smallheer at email@example.com or 802 254-2311, ext. 154.
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