The Exelon (NYSE:EXC) Limerick Unit 2 nuclear facility power reactor in Montgomery County, Pennsylvania went offline unexpectedly at 9 a.m. on June 1, according to an event report filed with the Nuclear Regulatory Commission (NRC).
The outage was due to an electrical component malfunction that impacted the unit’s recirculating water pumps. The pumps circulate water in the reactor and are not required for safe shutdown, Exelon said.
Technicians will repair the component and fully test the system before returning unit 2 to service, the company said in a news release.
“Limerick Unit 2 was manually scrammed from 100 [percent] power at 0900 [EDT] on 6/1/2016 in accordance with plant procedure OT-112 ‘Unexpected/Unexplained change in core flow’ when both 2A and 2B Recirculation Pump Adjustable Speed Drives (ASDs) tripped due to an electrical fault,” according to the NRC report.
All rods inserted fully on manual scram and the plant is in a normal shutdown electrical line up. Unit 1 was not affected by this event.
The licensee notified local counties and Pennsylvania Emergency Management Agency (PEMA).
The Limerick Generating Station is a dual-unit nuclear power plant with two boiling water reactors (BWRs) located in Limerick Township, Pennsylvania, approximately 35 miles outside of Philadelphia. Each unit can generate roughly 1,100 MW.
In 2014, Exelon received NRC license renewal for the Limerick station, which will allow both units to operate into the 2040s. The license renewal process has since been upheld by a federal appeals court.