Tuesday, October 04, 2011

NRC Discusses Preliminary Results from North Anna Inspections

The U.S. Nuclear Regulatory Commission held a public meeting yesterday to discuss its team’s preliminary inspection results on how the North Anna nuclear plant withstood the August 23 earthquake that rippled throughout the East Coast and the adequacy of the plant’s response.

What did they find?

David Heacock, Dominion’s president and chief nuCaptureclear officer, explains in a short video clip at the meeting:

The plant operated as designed with a few minor equipment problems and the people did a fantastic job operating the plant and safely shutting it down.

Each nuclear plant in the United States is built to safely withstand an earthquake—North Anna is no exception. But Heacock explains how having an additional safety margin helped the plant when the unexpected quake struck.

These plants were designed for a seismic event about the size of this seismic event, but for a much longer duration. Duration is very important. As duration gets longer, more and more energy gets imparted upon the plant. This event lasted about three seconds for the strong shaking, but we’re designed for a minimum of 15 seconds of strong shaking. So this is really about 20 percent of the energy the plant is designed to take.

Next steps: Starting tomorrow for about a 10-day period, the NRC will have a five-member crew conducting a thorough inspection at the site to ensure that all equipment is available and that there isn’t damage to safety equipment before the plant restarts. Last Friday the NRC outlined its post-earthquake requirements, which Dominion must meet before the plant is allowed to restart.

For more information, check out the NRC’s website where you can find current actions at the plant, a chronology of events, and frequently asked questions.

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