Operators of the Limerick Generating Station in Pottstown took Unit 1 offline Wednesday morning after an electrical disturbance on the non-nuclear side of the plant, according to Exelon.
Company spokesman Dana Melia said the electrical disturbance caused a loss of power to generator cooling equipment.
Melia said Unit 1 will remain offline until repairs, inspections and testing can be completed.
Limerick’s Unit 2 continues to operate at full power.
Melia said that as a result of the electrical disturbance, an “Unusual Event” was declared at 8:39 a.m. and terminated at 9:46 a.m. An Unusual Event is the lowest of four Nuclear Regulatory Commission emergency classifications.
Melia said Exelon Generation notified all appropriate federal, state and local government officials of the event, and that there is no threat to the health and safety of the public.
A Montgomery County spokesman confirmed local officials were notified of the incident.
“We did get an alert that there was an unusual event over there … there was an explosion inside a protected area of Unit 1, but it does not affect public safety,” said Frank Custer, communications director for Montgomery County.
“This is not an explosion like you would normally think,” said Diane Screnci, senior public affairs officer for the U.S. Nuclear Regulatory Commission in Philadelphia. “It’s more like when your house trips a circuit.”
Screnci said the incident resulted from an electrical fault in a transformer. She said the plant manually shut down the reactor.
“The plant responded as designed. It is stable,” she said. “There was no impact on the public or the workers.”