The Limerick Generating Station is a nuclear power plant in Pennsylvania located next to the Schuylkill River in Limerick Township, Montgomery County, northwest of Philadelphia. The facility has two General Electric boiling water reactor (BWR) units, cooled by natural draft cooling towers. According to its owner, Constellation Energy, the two units are capable of producing 2,317 megawatts of power, which combined would provide electricity to around 2 million households. Constellation owns and operates this facility following their separation from Exelon Corporation in 2022. With the exception of refueling outages, Limerick Generating Station continuously operates at 100% power. The plant is connected to the grid, and transmits power, via multiple 500kv transmission lines.

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Limerick Generating Station
NRC image of Limerick Generating Station, Units 1 & 2.
Country	United States
Location	Limerick Township, Montgomery County, Pennsylvania
Coordinates	40°13′36″N 75°35′14″W
Status	Operational
Construction began	June 19, 1974 (1974-06-19)
Commission date	Unit 1: February 1, 1986 Unit 2: January 8, 1990
Construction cost	$7.246 billion (2007 USD, Unit 1 only)[1]
Owner(s)	Constellation Energy
Operator(s)	Constellation Energy
Nuclear power station
Reactor type	BWR
Reactor supplier	General Electric
Cooling towers	2 × Natural Draft
Cooling source	Schuylkill River
Thermal capacity	2 × 3515 MWth
Power generation
Units operational	1 × 1130 MW 1 × 1134 MW
Make and model	BWR-4 (Mark II Containment)
Nameplate capacity	2264 MW
Capacity factor	93.77% (2017) 90.85% (lifetime)
Annual net output	19,309 GWh (2021)
External links
Website	Limerick Generating Station
Commons	Related media on Commons
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Limerick is a black start plant, meaning it doesn't require grid power for stator excitation. For critical standby power, Limerick depends on eight Fairbanks Morse 38 8-1/8 diesel engine generator sets that each deliver 3000 kilowatts of power and are capable of achieving rated speed within ten seconds of start.

The cooling towers for the Limerick Generating Station can be seen for miles away in parts of Montgomery, Chester, and Berks counties.

The site was chosen and plans to build the station were announced in 1969, by the Philadelphia Electric Company (now PECO Energy, a subsidiary of Exelon). It is located approximately one mile south of Sanatoga, PA. Community protests by the Keystone Alliance and other delays pushed the start of construction by the Bechtel Power Corporation to June 1974.

Limerick Unit 1 first attained criticality (began producing nuclear power, at limited capacity) on December 22, 1984 and was certified for commercial operation on February 1, 1986.

Limerick Unit 2 attained criticality on August 1, 1989, and commercial operation began on January 8, 1990.^[2]

On July 27, 1994, an F3 tornado struck the area surrounding the Limerick Generating Station. The tornado narrowly missed the station by two miles, but caused considerable damage to a nearby housing development in Limerick Township.^[3]

President George W. Bush visited the Limerick Generating Station in May 2006 to discuss nuclear power and its role in the Advanced Energy Initiative, which he announced at the 2006 State of the Union Address. He toured the facility, including a trip to the control room of the plant.^[4]

On October 20, 2014, the Nuclear Regulatory Commission (NRC) granted extensions for Limerick Units 1 and 2 for another 20 years. The units are now licensed to operate until 2044 and 2049 respectively.^[5]

Unit 2 of the station was scrammed from 100% power to a shutdown on June 1, 2016, at 9 am. The reactor was shut down due to an electrical fault, causing the recirculation pumps to stop. The steam bypass valves that lead to the main condenser were opened and Limerick went through a normal hot shutdown process.^[6]

The Nuclear Regulatory Commission estimates the risk of an earthquake intense enough to cause core damage to every reactor in the U.S. According to the NRC study published in August 2010, Limerick's earthquake risk was calculated at 1 in 18,868.^[8][9] Following the Fukushima Daiichi nuclear disaster in 2011, government regulators announced the plant would undergo further evaluations for seismic activity risk.^[10]

A quarry is located nearby which occasionally does blasting; however, this is done with the consent of plant staff.

The Nuclear Regulatory Commission defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone with a radius of 10 miles (16 km), concerned primarily with exposure to, and inhalation of, airborne radioactive contamination, and an ingestion pathway zone of about 50 miles (80 km), concerned primarily with ingestion of food and liquid contaminated by radioactivity.^[11]

The 2010 U.S. population within 10 miles (16 km) of Limerick was 252,197, an increase of 18.7 percent in a decade, according to an analysis of U.S. Census data for msnbc.com. The 2010 U.S. population within 50 miles (80 km) was 8,027,924, an increase of 6.1 percent since 2000.^[12]

Cities within 50 miles:

• Pennsylvania
  • Philadelphia (28mi/45km)
  • Allentown (27mi/43km)
  • Reading (19mi/31km)
• New Jersey
  • Trenton (Capital) (43mi/69km)
  • Camden (32mi/52km)
• Delaware
  • Wilmington (33mi/53km)

• Nuclear power
• Fricks Locks Historic District
• List of largest power stations in the United States