For decades no U.S. nuclear reactor had ever experienced a earthquake that exceeded what the plant was designed to withstand. That changed on Aug. 23 with the 5.8-magnitude quake that rattled much of the East Coast. Its epicenter was no more than 12 miles south of the North Anna nuclear power station on the shores of Lake Anna in central Virginia.
“Earthquakes aren’t supposed to happen here,” said Jorge Bermudez, a control room supervisor who was on duty when the quake struck.
Yet North Anna became the first nuclear plant to shut down after an earthquake in the 53-year history of commercial nuclear power in the U.S.
Now the plant, designed in the 1970s, will provide an important test case. As The New York Times reports, the North Anna plant will be evaluated by a special team assigned by the Nuclear Regulatory Commission, or NRC, to determine whether nuclear plants in the Northeast are quake-resistant.
“Real-world experience trumps all calculations,” said Roger Hannah, a spokesman for the NRC. “It provides an opportunity to have real empirical data you can put into the equation, rather than something that’s a computer model.”
As The Washington Post reports, an NRC spokesman said seismic monitors estimated that the plant shook at 26 percent of the force of gravity, well above the 18 percent force of gravity standard to which the facility’s containment buildings were designed. The shock was big enough to make 117-ton canisters of spent fuel move a few inches on their storage pad.
The examination of the North Anna plant comes as the NRC itself is coming under closer scrutiny, both because of the Virginia temblor and the meltdown at Japan’s Fukushima Daiichi nuclear plant after it was struck by an earthquake and tsunami in March. Sen. Barbara Boxer, the California Democrat who chairs the Senate’s Environment and Public Works Committee, is among those who have questioned the NRC’s commitment to safety.
Initial indications are that the North Anna plant came through the episode well.
Officials of Dominion Virginia Power, which owns the plant, told NRC inspectors Thursday that they have found no significant damage to safety-related structures or systems.
Company officials told the NRC that one reactor could be restarted as soon as Sept. 22, and the other by Oct. 13. The restarts would require NRC approval, however, and the commission did not indicate when that might happen.
ROBERT T. NELSON
East Coast Quake Raises Safety Concerns About U.S. Nuclear Reactors
Japan Admits Lax Nuke Oversight, Doubles Estimate on Radiation Release
Safety Review to Evaluate U.S. Nuclear Power Plants