North Anna Nuclear Power Station Shut Down Following East Coast Earthquake
Washington, DC—(ENEWSPF)—August 29, 2011. The Nuclear Regulatory Commission (NRC) has dispatched an Augmented Inspection Team to the North Anna nuclear power station to further review the effects of last week’s earthquake, the operators’ response and the plant staff’s activities to check equipment.
Just after 2 p.m. on Tuesday, August 23, an Alert was declared at the North Anna station which is operated by Dominion near Louisa, Va., about 40 miles northwest of Richmond. The station’s two units automatically shut down after the facility lost offsite power. Emergency diesel generators provided power to cool the reactors until offsite power was restored a few hours later. Anna station exited the Alert after offsite power was restored.
The station remains shut down and the company continues to review data from the quake and assess possible effects. No significant damage to safety systems has been identified, but Dominion has reported to the NRC that initial reviews determined the plant may have exceeded the ground motion for which it was designed. This determination is in line with NRC’s preliminary independent analyses, although data is still being collected and analyzed to determine the precise level of shaking that was experienced at key locations within the North Anna facility. The company and the NRC will continue to carefully evaluate information to determine if additional actions may be necessary. NRC regulations require that the station not start up until it can demonstrate that no functional damage occurred to those features needed for continued safe operation.
The NRC initially dispatched a seismic expert and another structural expert to assist the agency’s resident inspectors on site. Further reviews indicated that additional inspection is warranted. The NRC inspection has now been officially classified as an AIT or Augmented Inspection Team.
An AIT is formed by the NRC to review more significant events or issues at NRC-licensed facilities. The AIT will include technical experts from NRC headquarters in Rockville, MD., as well as two additional inspectors from the regional offices in Atlanta. The AIT will be led by NRC Region II Branch Chief Mark Franke and North Anna Senior Resident Inspector Greg Kolcum and will officially begin work at the North Anna station on Tuesday.
“The fact that we’re sending an AIT should not be interpreted to mean that Dominion staff responded inappropriately or that the station is less safe as a result of the quake,” said NRC Region II Administrator Victor McCree. “An AIT provides us with the resources needed to completely understand all the effects at North Anna and gather important information for the NRC’s continuing evaluation of earthquake risk at all U.S. nuclear plants.”
The AIT will hold an exit meeting with the company upon completion of the inspection to discuss its preliminary findings. The AIT will also issue a written report 30 days after the completion of the inspection.