NRC APPROVES RESTART OF NORTH ANNA REACTORS, WILL ENSURE DOMINION MEETS COMMITMENTS
| No. 11-212 | November 11, 2011 |
The Nuclear Regulatory Commission, after careful analysis of inspection findings and related information, has concluded Dominion Generation’s North Anna Unit 1 and 2 reactors can be restarted. The North Anna reactors, in Louisa, Va., have been shut down since Aug. 23, when a magnitude 5.8 earthquake occurred about 11 miles from the plant.
“The earthquake shook the reactors more strongly than the plant’s design anticipated, so Dominion had to prove to us that the quake caused no functional damage to the reactors’ safety systems,” said Eric Leeds, director of the NRC’s Office of Nuclear Reactor Regulation. “We’ve asked Dominion dozens of detailed questions, and our experts have examined Dominion’s answers as well as information from our own inspections. We’re satisfied the plant meets our requirements to restart safely, and we’ll monitor Dominion’s ongoing tests and inspections during startup of both reactors.”
The NRC issued Dominion a letter describing the staff’s review, which started with existing guidance for determining a reactor’s response to an earthquake. The staff used more recent experience, including insights learned from a reactor site in Japan damaged by a 2007 earthquake, in asking Dominion additional questions regarding proper examination of technical areas that included: piping systems, including buried segments; nuclear fuel assemblies; steam generators; pumps and valves; and emergency diesel generators.
The NRC’s independent actions included an Augmented Inspection Team (AIT) that examined the plant shortly after the quake, as well as a restart readiness inspection in mid-October. Both Dominion and NRC’s results showed only minor damage that did not affect North Anna’s safety systems. The NRC held public meetings near the plant on Oct. 3 regarding the AIT’s findings, and on Nov. 1 regarding the restart readiness inspection findings and the staff’s technical review.
The NRC also held a public meeting at the agency’s Rockville, Md., headquarters Sept. 8 regarding Dominion’s initial assessment. On Oct. 21 the staff briefed the Commission regarding the plant’s response to the earthquake.
The NRC has issued Dominion a separate letter documenting the company’s commitment to several additional quake-related actions, including:
• Updating North Anna’s Final Safety Analysis Report to incorporate information from the quake and subsequent analysis;
• Additional characterization of the fault responsible for the Aug. 23 quake, as well as any special ground motion effects at North Anna;
• Re-evaluating plant equipment (including an assessment of potential improvements) identified in earlier seismic reviews; • Developing any needed inspections or evaluations for components within the North Anna reactor vessels; and
• Permanently updating seismic monitoring equipment for the North Anna reactors and dry-cask spent fuel storage facility.
The staff’s letters to Dominion, as well as its technical evaluation, will be available on the NRC’s Virginia quake Web page.
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