An earthquake on Tuesday forced two nuclear reactors to shut down in the town of Mineral, Virginia, at the quake's epicenter, but other plants on the U.S. East Coast were unaffected.
After the magnitude 5.9 earthquake, Dominion Resources shut its North Anna Station nuclear power plant, the Nuclear Regulatory Commission said. The company said there was no "major" damage but it wasn't yet clear when it would be safe to restart the North Anna plant in Mineral, a town north of Richmond and about 83 miles from Washington.
Two reactors at the Mineral plant were stopped after a power outage, the NRC said. Diesel generators kicked in after the plant lost off-site power, a Dominion spokesman said.
The U.S. Geological Survey said the town of Mineral was at the quake's epicenter.
The plant shut down automatically and safely after the quake, and represents no danger to the public, the NRC said.
"The plants were designed for this kind of seismic event," Dominion official David Heacock told CNN.
North Anna is an 1,806-megawatt power plant.
Dominion's two-unit Surry plant in Gravel, Virginia, continued to operate normally.
Tuesday's quake was felt along the East Coast as far north as Canada.
Nine other plants in the region between Virginia and New Jersey declared an "unusual event", the lowest of the NRC's emergency classification ratings, but all continued to operate at full power, including Entergy's Indian Point nuclear plant located north of New York city.
There are 60 nuclear reactors operating along the Eastern Seaboard from Florida to New England.
Concerns have risen about nuclear plant preparedness since a massive March quake and tsunami in Japan crippled reactors at Japan's Fukushima Daiichi plant and led to a meltdown.