Dominion Resources Inc. successfully restored power to a Virginia nuclear plant knocked offline during yesterday's magnitude-5.8 earthquake, but utilities are now girding for a hurricane this weekend expected to move up the Atlantic Coast.

Hurricane Irene will most likely affect Dominion's 1,598-megawatt Surry Power Station in southeastern Virginia and Progress Energy Inc.'s Brunswick nuclear plant near Southport, N.C., said Roger Hannah, a spokesman for the Nuclear Regulatory Commission.

The storm, packing winds up to 115 mph, has strengthened to a Category 3 hurricane, according to the National Weather Service. The storm is expected to expand early Friday as it leaves the Bahamas, skirting Florida and bearing down on the Carolinas by early Saturday morning (ClimateWire, Aug. 24).

Workers at the Brunswick plant are conducting inspections, "tightening up" equipment, doing security checks and preparing for any damage that might stem from tropical storm-force winds, said Mike Hughes, a spokesman for Progress.

The two-unit Brunswick plant was built in the 1970s and draws cooling water from the Cape Fear River. The plant can withstand a 22-foot storm surge and winds of 128 mph, as well as a magnitude-6.2 earthquake, Hughes said.

Workers at the Surry plant are conducting similar safety measures and plan to reduce power if winds exceed 75 mph, said Jim Norvelle, a spokesman for Dominion. The Surry plant came into operation in the '70s and sits on the south bank of the James River in southeastern Virginia.

Irene is arriving on the heels of yesterday's earthquake, which knocked out off-site power for two reactors at Dominion's North Anna Power Station in Louisa, Va.

Norvelle said power has been restored to the plant, which is located 14 miles from the epicenter of yesterday's temblor. The plant automatically shut down after losing power yesterday, Hannah said (E&ENews PM, Aug. 23).

The North Anna plant was designed to handle a magnitude-6.2 earthquake, Norvelle said. Dominion and NRC are not sure why the plant lost off-site power but say the quake may have damaged equipment in the electrical switchyard, which is needed to provide electricity to the nuclear plant. The North Anna plant is too far inland to be affected by Hurricane Irene, Hannah said.

Federal nuclear regulators are revamping safety requirements for U.S. nuclear reactors to protect them from double threats like the magnitude-9 earthquake and tsunami that struck Japan's Fukushima Daiichi nuclear complex on March 11.

NRC officials are now digesting safety recommendations from an internal task force after inspections revealed that many operators aren't implementing emergency precautions appropriately (Greenwire, June 27).

NRC officials revealed that one diesel generator at the North Anna plant failed to operate yesterday, a finding that garnered alarm from House Natural Resources Committee ranking member Ed Markey (D-Mass.).

"The Fukushima meltdown was a long-distance warning to the U.S. nuclear industry to bolster its safety systems, including backup power reliability and redundancy," Markey said in a statement. "The Virginia earthquake is now our local 911 call to stop delaying the implementation of stricter safety standards."

Markey asked NRC in a letter today to prescribe and enforce maintenance requirements to ensure that generators operate as intended.