The Three Mile Island accident was a partial meltdown of the Three Mile Island, Unit 2 (TMI-2) reactor on the Susquehanna River in Londonderry Township, Pennsylvania, near the Pennsylvania capital of Harrisburg. It began at 4 a.m. on March 28, 1979, and released radioactive gases and radioactive iodine into the environment. It is the worst accident in U.S. commercial nuclear power plant history. On the seven-point International Nuclear Event Scale, it is rated Level 5 – Accident with Wider Consequences.
A pressurized water reactor (PWR) is a type of light-water nuclear reactor. PWRs constitute the large majority of the world's nuclear power plants. In a PWR, the primary coolant (water) is pumped under high pressure to the reactor core where it is heated by the energy released by the fission of atoms. The heated, high pressure water then flows to a steam generator, where it transfers its thermal energy to lower pressure water of a secondary system where steam is generated. The steam then drives turbines, which spin an electric generator. In contrast to a boiling water reactor (BWR), pressure in the primary coolant loop prevents the water from boiling within the reactor. All light-water reactors use ordinary water as both coolant and neutron moderator. Most use anywhere from two to four vertically mounted steam generators; VVER reactors use horizontal steam generators.
The Nuclear Regulatory Commission (NRC) is an independent agency of the United States government tasked with protecting public health and safety related to nuclear energy. Established by the Energy Reorganization Act of 1974, the NRC began operations on January 19, 1975, as one of two successor agencies to the United States Atomic Energy Commission. Its functions include overseeing reactor safety and security, administering reactor licensing and renewal, licensing radioactive materials, radionuclide safety, and managing the storage, security, recycling, and disposal of spent fuel.
The Limerick Generating Station in Pennsylvania is 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. The two units are capable of producing over 2,200 megawatts of power, which combined would provide electricity to over 2 million households. Constellation Energy owns and operates this facility following 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 by several 500kv transmission lines.
Three Mile Island Nuclear Generating Station is a closed nuclear power plant on Three Mile Island in Londonderry Township, Dauphin County, Pennsylvania on Lake Frederic, a reservoir in the Susquehanna River just south of Harrisburg. It has two separate units, TMI-1 and TMI-2.
Oyster Creek Nuclear Power Station was a single unit 636 MWe boiling water reactor power plant in the United States. The plant is located on an 800-acre (3.2 km2) site adjacent to Oyster Creek in the Forked River section of Lacey Township in Ocean County, New Jersey. At the time of its closure, the facility was owned by Exelon Corporation and, along with unit 1 at Nine Mile Point Nuclear Generating Station, was the oldest operating commercial nuclear power plant in the United States. The plant first started commercial operation on December 23, 1969, and is licensed to operate until April 9, 2029, but Oyster Creek was permanently shut down in September 2018. The plant got its cooling water from Barnegat Bay, a brackish estuary that empties into the Atlantic Ocean through the Barnegat Inlet.
Dresden Generating Station is the first privately financed nuclear power plant built in the United States. Dresden 1 was activated in 1960 and retired in 1978. Operating since 1970 are Dresden units 2 and 3, two General Electric BWR-3 boiling water reactors. Dresden Station is located on a 953-acre (386 ha) site in Grundy County, Illinois, at the head of the Illinois River, near the city of Morris. It is immediately northeast of the Morris Operation—the only de facto high-level radioactive waste storage site in the United States. It serves Chicago and the northern quarter of the state of Illinois, capable of producing 867 megawatts of electricity from each of its two reactors, enough to power over one million average American homes.
Braidwood Generating Station is located in Will County in northeastern Illinois, U.S. The nuclear power plant serves Chicago and northern Illinois with electricity. The plant was originally built by Commonwealth Edison company, and subsequently transferred to Com Ed's parent company, Exelon Corporation. Following Exelon's spin-off of their Generation company, the station was transferred to Constellation Energy.
The Byron Nuclear Generating Station is a nuclear power plant located in Ogle County, Illinois, 2 miles (3.2 km) east of the Rock River. The reactor buildings were constructed by Commonwealth Edison and house two Westinghouse Four-Loop pressurized water reactors, Unit 1 and Unit 2, which began operation in September 1985 and August 1987 respectively. The plant is owned and operated by Constellation Energy.
The Robert Emmett Ginna Nuclear Power Plant, commonly known as Ginna, is a nuclear power plant located on the southern shore of Lake Ontario, in the town of Ontario, Wayne County, New York, United States, approximately 20 miles (32 km) east of Rochester, New York. It is a single unit Westinghouse 2-Loop pressurized water reactor, similar to those at Point Beach, Kewaunee, and Prairie Island. Having gone into commercial operation in 1970, Ginna became the second oldest nuclear power reactor, after Nine Mile unit 1, still in operation in the United States when the Oyster Creek power plant was permanently shut down on September 17, 2018.
Peach Bottom Atomic Power Station, a nuclear power plant, is located 50 miles (80 km) southeast of Harrisburg in Peach Bottom Township, York County, Pennsylvania, on the Susquehanna River three miles north of the Maryland border.
The Enrico Fermi Nuclear Generating Station is a nuclear power plant on the shore of Lake Erie near Monroe, in Frenchtown Charter Township, Michigan on approximately 1,000 acres (400 ha). All units of the plant are operated by the DTE Energy Electric Company and owned by parent company DTE Energy. It is approximately halfway between Detroit, Michigan, and Toledo, Ohio. It is also visible from parts of Amherstburg and Colchester, Ontario as well as on the shore of Lake Erie in Ottawa County, Ohio. Two units have been constructed on this site. The first unit's construction started on August 4, 1956 and reached initial criticality on August 23, 1963, and the second unit received its construction permit on September 26, 1972. It reached criticality on June 21, 1985 and was declared commercial on November 18, 1988. The plant is connected to two single-circuit 345 kV Transmission Lines and three 120 kV lines. They are operated and maintained by ITC Transmission.
The Shippingport Atomic Power Station was the world's first full-scale atomic electric power plant devoted exclusively to peacetime uses. It was located near the present-day Beaver Valley Nuclear Generating Station on the Ohio River in Beaver County, Pennsylvania, United States, about 25 miles (40 km) from Pittsburgh.
Quad Cities Generating Station is a two-unit nuclear power plant located near Cordova, Illinois, United States, on the Mississippi River. The two General Electric boiling water reactors give the plant a total gross electric capacity of approximately 1,880 MW. It was named for the nearby cities of Moline, Illinois, Rock Island, Illinois, Davenport, Iowa, East Moline, Illinois, and Bettendorf, Iowa — known as the Quad Cities.
Nuclear power in the United States is provided by 92 commercial reactors with a net capacity of 94.7 gigawatts (GW), with 61 pressurized water reactors and 31 boiling water reactors. In 2019, they produced a total of 809.41 terawatt-hours of electricity, which accounted for 20% of the nation's total electric energy generation. In 2018, nuclear comprised nearly 50 percent of US emission-free energy generation.
The Susquehanna Steam Electric Station, a nuclear power station, is on the Susquehanna River in Salem Township, Luzerne County, Pennsylvania.
Nuclear safety in the United States is governed by federal regulations issued by the Nuclear Regulatory Commission (NRC). The NRC regulates all nuclear plants and materials in the United States except for nuclear plants and materials controlled by the U.S. government, as well those powering naval vessels.
Joseph Mallam Hendrie is a former chairman of the U.S. Nuclear Regulatory Commission (NRC). On August 9, 1977 he was named to a four-year term on the Commission and designated as its chairman by President Jimmy Carter. From 1975 to 1977, Hendrie had served as chairman of the Department of Applied Science at Brookhaven National Laboratory.
The United States Government Accountability Office reported more than 150 incidents from 2001 to 2006 of nuclear plants not performing within acceptable safety guidelines. According to a 2010 survey of energy accidents, there have been at least 56 accidents at nuclear reactors in the United States. The most serious of these was the Three Mile Island accident in 1979. Davis-Besse Nuclear Power Plant has been the source of two of the top five most dangerous nuclear incidents in the United States since 1979. Relatively few accidents have involved fatalities.
This is a history of nuclear power.
