U.S. Nuclear Plants

Three Mile Island
Pennsylvania

Unit 1 Nuclear system supplied by Babcock and Wilcox
Capacity Net MW(e)	Generation in 2003 Megawatthours	Capacity Factor	Type	On-line Date	License Expiration Date
816	6,197,031	86.5 %	PWR	April 19, 1974	April 19, 2014

PWR= Pressurized Light Water Reactor

Description: The Three Mile Island station is located on 814 acres of an island near the state capitol at Harrisburg. Three Mile Island may be the most widely known nuclear power plant in the United States due to an accident to its number 2 reactor. The second reactor was permanently shut down following an accident on March 28, 1979. A combination of equipment malfunctions and human error led to a loss of coolant. It remains the most significant accident on record at a U.S. nuclear power plant.

Ownership: Three Mile Island (TMI) is owned by Exelon. It is operated by AmerGen Energy Company.

The Impact of the Nuclear Industry on Pennsylvania

Highlights : The First (U.S.) EIA Highlights Shippingport Power Plant
Nuclear-provided Electricity Generation
Competition in the State Electricity Market
Environmental Trends: Emissions levels
Various Links to related sites.

Sources: Capacity, for purposes of this report, is the net summer capability as reported in Energy Information Administration (EIA) survey form 860, "Annual Electric Generator Report." Capacity Factor is a calculation in which the maximum possible generation (based on net summer capability) is divided into the actual generation than multiplied by 100 to get a percentage. Generation is the electricity output reported by plant owners on EIA survey form 902. Type of Unit: All U.S. commercial reactors currently in operation are one of two types: BWR (boiling water reactor) or PWR (pressurized light water reactor). The type is identified in EIA's Nuclear Power Generation and Fuel Cycle Report. Both the On-line Date and the License Expiration Date are reported annually in Information Digest by the U.S. Nuclear Regulatory Commission.

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