Aug 31, 2011

Earthquake may have exceeded Virginia nuclear plant's safeguards earthquake that prompted the shutdown of a Virginia nuclear power plant last week may have been more severe than the plant’s reactors were designed to withstand, federal regulators said.

The revelation is likely to put increased pressure on the Nuclear Regulatory Commission (NRC) to quickly implement a series of safety recommendations intended in part to protect plants from major natural disasters like earthquakes.

NRC said Monday that its preliminary analysis indicates that the ground motion caused by the magnitude-5.8 earthquake near the North Anna Power Station in Louisa County, Va., exceeded the maximum level the two reactors at the plant were built to handle.

"We have informed the NRC that preliminary reports from instruments show the earthquake potentially exceeded the design basis," Dominion spokesman Ryan Frazier said. "All reports are not final, and probably will not be until the end of the week." Frazier stressed that inspections have found no major damage to the plant. "All safety systems operated as designed and built," he said.

Dominion restored power to the plant late Tuesday night and lifted an emergency alert the following day.

While there have been no reports of major damage at the plant, nuclear critics have pounced on the incident, arguing that it highlights the vulnerability of the U.S. nuclear fleet to major natural disasters.

A federal task force said in a report released last month that the NRC should make wide-ranging improvements to the “existing patchwork of regulatory requirements and other safety initiatives.” The task force was mandated by President Obama in the aftermath of the nuclear disaster at Japan’s Fukushima Daiichi power plant.

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