Operations at the Exelon Peach Bottom nuclear power plant in Delta, PA, were unaffected by Tuesday's 5.8 magnitude earthquake, a spokesman for the site told Patch. But personnel knew it happened.
"Absolutely we felt it here at Peach Bottom," said Dave Tillman, a spokesman at the plant. "We declared what's called an unusual event. ... That is a procedural declaration—the lowest of our four emergency [declarations]."
The plant is about 20 miles north of Bel Air along the Susquehanna River. It services northern Harford and parts of Cecil County, but a nuclear meltdown could spread as far south as Baltimore.
Three other mid-Atlantic Exelon plants declared a similar emergency: Three Mile Island and Limerick, also in Pennsylvania, and Oyster Creek in New Jersey. The declaration was lifted at about 5:45 p.m.
According to the U.S. Nuclear Regulatory Commission 12 nuclear plants reported unusual events and one, in North Anna, VA, reported an “alert.” Declaring an unusual event triggers certain inspections, said David McIntyre, an NRC spokesman.
“It’s unusual” for so many nuclear facilities to declare an unusual event at once, McIntyre said.
"North Anna declared its Alert, the second-lowest of the NRC’s four emergency classifications, when the plant lost electricity from the grid following the quake just before 2 p.m. Tuesday," according to an NRC press release. "Power is being provided by onsite diesel generators and the plant’s safety systems are operating normally. Plant personnel and NRC resident inspectors are continuing to examine plant conditions.
"NRC staff in the Maryland headquarters felt the quake and immediately began checking with U.S. nuclear power plants," the press release added. "The NRC is in direct communications with North Anna and is coordinating its response with other federal agencies."
A plant walk-down was underway at Peach Bottom "to confirm that the event has not damaged plant equipment or operations," Tillman said. "We're designed for robust seismic activities."
Tillman said there were no evacuations at the plant and it operated at full power throughout the earthquake.
"Nuclear power plants are built to withstand environmental hazards, including earthquakes," according to the NRC press release. "Even those plants that are located outside of areas with extensive seismic activity are designed for safety in the event of such a natural disaster. The NRC requires that safety-significant structures, systems, and components be designed to take into account the most severe natural phenomena historically reported for the site and surrounding area."
"Plants declaring Unusual Events, which indicate a potential decrease in plant safety, include Peach Bottom, Three Mile Island, Susquehanna and Limerick in Pennsylvania; Salem, Hope Creek and Oyster Creek in New Jersey, Calvert Cliffs in Maryland, Surry in Virginia, Shearon Harris in North Carolina and D.C. Cook and Palisades in Michigan. All these plants continue to operate while plant personnel examine their sites."