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NRC, Industry Discuss Details of Fukushima Response

The following story originally appeared in NEI’s Nuclear Energy Overview.

The nuclear industry and NRC staff appear generally to be in alignment on a variety of issues regarding the implementation of orders incorporating safety lessons from the agency’s Fukushima task force, though some differences remain to be worked out.

A public meeting last week of NRC and industry Fukushima response steering committees discussed a variety of topics, including seismic revaluations, filtered vents and land contamination.

“I think we have a path forward,” said Martin Virgilio, the NRC’s deputy executive director for reactor and preparedness programs.

The industry and the agency are working toward agreement on the re-evaluation of plants’ seismic safety margins. The industry emphasized that NRC-prescribed deadlines to conduct the re-evaluations could be met only if the assumptions used and the data collected have reasonable limits that enable the work to be completed in time.

“The plants are very seismically hardy and other issues might be a greater vulnerability than seismic issues,” said David Heacock, president and chief nuclear officer of Dominion Nuclear.

Heacock said that one of the industry’s proposals to meet the NRC’s timeline is to use current seismic site characterization data, instead of recreating the data.

NRC staff said that the agency had taken note of the industry’s stance on how seismic re-evaluations could be most efficiently completed.

“These are all things that have been part of the dialogue, and I agree they are worthwhile for us to consider,” said Michael Johnson, assistant for operations in the NRC’s office of the executive director for operations.

The overall industry approach for responding to the NRC’s Fukushima-related orders and requests for information remains flexibility and redundancy, said Jim Scarola, Progress Energy’s senior vice president and chief nuclear officer.

“Our approach to this all along is the versatility of having different options … When we’re dealing with an event that’s yet to be defined and won’t be defined until the day it occurs, [having] options will be the best approach,” said Scarola.

Industry and NRC representatives also discussed the issue of filtered vents. An order issued March 12 requires reliable hardened—but not necessarily filtered—vents for boiling water reactors with Mark I and Mark II containments. Of the 104 U.S. reactors, 31 use these containment designs.

“We are continuing to assess whether the vents that were required by the order … for [BWR] Mark I and Mark II containment should be filtered,” Virgilio said. “We are committed to provide to the commission our recommendation on this issue in July.”

Virgilio said that the review would be based on “our best engineering” and on lessons learned from Fukushima. In addition, he said, NRC staff will visit European reactors to investigate other countries’ experience with filtered vents. Virgilio added that the agency is interested in alternative approaches to installing filtered vents.

Industry participants said that other safety modifications could result in a level of safety benefit similar to that of filtered vents. “If you are managing a damaged core, managing containment, you are addressing the heart of the issue and there are modifications that are more beneficial than filtration,” said Maria Korsnick, Constellation Energy Nuclear Group’s chief nuclear officer and chief operating officer.

Virgilio said that NRC staff also is working on a paper on the “economic consequences of land contamination” from radioactive materials following a reactor accident. Virgilio said the staff would be working on this paper “in parallel” with its paper on filtered vents. Virgilio added that cost-benefit analysis would be one of the tools used to analyze the land contamination issue.

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