LaSalle County Nuclear Generating Station, located in

Brookfield Township, LaSalle County, Illinois Brookfield Township is located in LaSalle County, Illinois Illinois ( ) is a state in the Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Lo ...

, near Marseilles, southeast of Ottawa, serves

Chicago (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name ...

and

Northern Illinois Northern Illinois is a region generally covering the northern third of the U.S. state of Illinois. The region is by far the most populous of Illinois with nearly 9.7 million residents as of 2010. Economics Northern Illinois is dominated by t ...

with electricity. The plant is owned and operated by

Constellation Energy Constellation Energy Corporation () is an energy company headquartered in Baltimore, Maryland, United States. The company provides electric power, natural gas, and energy management services. It has approximately two million customers across th ...

following separation from Exelon Corporation in 2022. Its Units 1 and 2 began commercial operation in October 1982, and October 1984, respectively. It has two

General Electric General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable en ...

boiling water reactor A boiling water reactor (BWR) is a type of light water nuclear reactor used for the generation of electrical power. It is a design different from a Soviet graphite-moderated RBMK. It is the second most common type of electricity-generating nu ...

s. LaSalle's Unit 1 and Unit 2 together produce 2,320

megawatt The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James ...

s, which is enough electricity for the needs of 2.3 million American homes. Instead of

cooling tower A cooling tower is a device that rejects waste heat to the atmosphere through the cooling of a coolant stream, usually a water stream to a lower temperature. Cooling towers may either use the evaporation of water to remove process heat an ...

s, the station has a man-made cooling lake, which is also a popular fishery —

LaSalle Lake State Fish and Wildlife Area LaSalle Lake State Fish and Wildlife Area is an Illinois state park on in LaSalle County, Illinois, United States. It is a man-made lake, built as a cooling pond A cooling pond is a man-made body of water primarily formed for the purpose of ...

— managed by the

Illinois Department of Natural Resources The Illinois Department of Natural Resources (IDNR) is the code department of the Illinois state government that operates the state parks and state recreation areas, enforces the fishing and game laws of Illinois, regulates Illinois coal mines, ...

Electricity generation

Surrounding population

The Nuclear Regulatory Commission defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone with a radius of , concerned primarily with exposure to, and inhalation of, airborne

radioactive contamination Radioactive contamination, also called radiological pollution, is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids, or gases (including the human body), where their presence is unintended or undesirab ...

, and an ingestion pathway zone of about , concerned primarily with ingestion of food and liquid contaminated by radioactivity. The 2010 U.S. population within of LaSalle was 17,643, an increase of 7.1 percent in a decade, according to an analysis of U.S. Census data for msnbc.com. The 2010 U.S. population within was 1,902,775, an increase of 22.6 percent since 2000. Cities within 50 miles include Joliet (34 miles to city center).

Site area emergency

On February 20, 2006, a "site area emergency" was declared at the plant at 12:28 AM. This was the first SAE declared at a US nuclear plant since 1991. Workers were shutting down Unit 1 for refueling when the plant's turbine control system malfunctioned, SCRAMing the reactor. The reactor had been operating at 6 percent power output at the time. Plant instruments indicated three of 185 control rods used to shut down the reactor were not fully inserted triggering the emergency declaration. After a reset, the plant's instruments indicated that only one control rod was not fully inserted, not three. The emergency ended at 4:27 AM with no damage or release of radioactivity. Post trip evaluations have confirmed that all control rods were fully inserted within four minutes of the reactor SCRAM. A review indicates the problem was with the indication sensors, and that all control rods were fully inserted immediately at the time of the reactor scram. Follow-up evaluations also demonstrated that even if the three subject control rods remained fully withdrawn in a cold shutdown condition, the reactor would have remained adequately shutdown.

Seismic risk

The Nuclear Regulatory Commission's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at LaSalle was 1 in 357,143, according to an NRC study published in August 2010.

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