Dominion Virginia Power's North Anna Power Station was back at full power on Monday. It's been offline since the Aug. 23 earthquake that shook the East Coast.
The two nuclear reactors at the plant, located about 50 miles northwest of Richmond, Va., and 11 miles from the quake's epicenter, automatically shut down after the 5.8-magnitude earthquake caused ground movement around twice the level for which the plant was designed. Multiple inspections by both Dominion and federal regulators found that the plant's twin 1,800-megawatt reactors and other safety components did not suffer any functional damage.
The plant had some minor damage, ranging from small buckles and cracks in tile floors to damaged bolts on large metal parts that transfer power from transformers to the electrical grid and into homes. The quake also caused 25 massive nuclear storage containers at the plant to shift, but they remained intact.
North Anna was the first operating U.S. nuclear plant to shut down because of an earthquake. Dominion got the go-ahead from the U.S. Nuclear Regulatory Commission to restart the reactors on Nov. 11. According to the NRC's Power Reactor Status Report website, Unit 1 was back at 100 percent on Nov. 18. It said Unit 2 was at 74 percent as of Sunday before ramping up to full power on Monday.
Dominion spokesman Rick Zuercher said both units were actually at full power as of early Saturday.
The company expected it would take about 10 days for the plant to be fully operational as both reactors were restarted in phases and testing of all safety equipment and inspections of containment areas were done during that process.
"It did take us a little longer than we thought," Zuercher said. "We thoroughly inspected that station and found nothing significant and the NRC did its own independent assessment. ... It's very safe to operate."
A problem with an electrical connector, tuning a new turbine and minor pump repairs delayed the restart of the second unit, Zuercher said.
Various groups have said the quake and subsequent shutdown at North Anna Power Station focused attention on the danger of another quake in the area. Some have asked Dominion to retrofit the two reactors at the plant to higher earthquake safety standards.
The NRC has said it plans to order all U.S. plants to update their earthquake risk analyses, a complex exercise that could take two years for some plants. The review, launched well before the East Coast quake and the Japan nuclear disaster in March, marks the first complete update to seismic risk in years for the nation's 104 reactors.
The North Anna reactors are among 27 in the eastern and central U.S. that may need upgrades, according to a preliminary NRC review.
When fully operational, the Virginia facility produces enough energy to power about 450,000 homes. Dominion had been using other power sources in its generation system or buying power while the plant was offline.
The company is weighing the addition of a third reactor at the plant. It will reassess that plan when it receives operating approval from the NRC, expected in 2013.
Dominion Virginia Power is a subsidiary of Richmond-based Dominion Resources Inc., one of the nation's largest producers and transporters of energy and has the nation's largest natural gas storage system. It serves retail customers in 15 states.
Michael Felberbaum can be reached at http://www.twitter.com/MLFelberbaum.