Callaway Nuclear Generating Station

The Callaway Plant is a nuclear power plant located in Callaway County, Missouri. The plant is Missouri's only nuclear power plant and is close to Fulton, Missouri. The 2767 acre site began operations on December 19, 1984. It generates electricity from one 1,190-megawatt Westinghouse four-loop pressurized water reactor and a General Electric turbine-generator. The Ameren Corporation owns and operates the plant through its subsidiary Ameren Missouri. It is one of several Westinghouse reactors designs called the "Standard Nuclear Unit Power Plant System," or SNUPPS.

The plant produces 1,279 electrical megawatts (MWe) of net power. As of 2019, Callaway has completed five "breaker-to-breaker" runs — operating from one refueling to the next without ever being out of service. It is one of only 26 U.S. reactors to achieve such a feat according to Ameren.

History
On November 19, 2005, its workers finished replacing all four steam generators in 63 days, 13 hours, a world record for a four-loop plant.

In 2014, the Nuclear Regulatory Commission tests found contaminated ground water near the site.

The plant experienced three unplanned shutdowns in 2020. On December 24, 2020, an electric fault on the non-safety main generator caused an extensive outage requiring the replacement of significant components. The components were replaced, inspected, and tested during subsequent months. According to NRC inspection reports, on August 2, 2021, the reactor was restarted. Two days later on August 4, 2021, the main turbine generator was synchronized with the electrical grid and on August 8, the plant reached rated thermal power.

According to Ameren, Callaway accounted for 23% of the utility's generation mix in 2022.

Proposed Unit 2 and cancellation
On July 28, 2008, Ameren Missouri applied to the U.S. Nuclear Regulatory Commission (NRC) for a Combined Construction and Operating License (COL) to build a 1,600-MW Areva Evolutionary Power Reactor. Ameren sought to construct this second reactor in order to meet their projected increase in demand for electricity over the next decade.

In April 2009, the proposal was cancelled. One stumbling block was a law that forbids utilities to charge customers for the interest accrued on a construction loan before a new plant produces electricity. The new nuclear reactor would have cost at least $6 billion.

In April 2012, Ameren Missouri and Westinghouse Electric Company announced their intent to seek federal funding for a new generation of nuclear reactors to be installed at the Callaway site. The U.S. Department of Energy could provide up to $452 million in research and development funds to Westinghouse. The new reactors would be smaller and, the companies claimed, safer in design than any currently operating. Ameren Missouri was to apply to license up five of the 225-megawatt reactors at the Callaway site, more than doubling its current electrical output.

In August 2015, a month after Ameren had announced plans to build solar energy plants in Missouri, all plans to expand nuclear-powered electricity generation at the site were scrapped.

Cooling tower
The cooling tower at Callaway is 553 ft tall. It is 430 feet wide at the base, and is constructed from reinforced concrete. It cools about 585000 gal of water per minute when the plant is operating at full capacity; about 15000 gal of water per minute are lost out the top from evaporation. Another 5000 gal of water are sent to the Missouri River as "blowdown" to flush solids from the cooling tower basin. All water lost through evaporation or blowdown is replaced with water from the river, located five miles from the plant. The temperature of the water going into the cooling tower is 125 °F, and the tower cools it to 95 °F. The tower is designed such that if it were to somehow topple over completely intact, it would not damage any of the critical plant structures.

Surrounding population
The Nuclear Regulatory Commission defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone with a radius of 10 mi, concerned primarily with exposure to, and inhalation of, airborne radioactive contamination; and an ingestion pathway zone of about 50 mi, concerned primarily with ingestion of food and liquid contaminated by radioactivity.

The 2010 population within 10 mi of Callaway was 10,092, an increase of 3.8 percent in a decade, according to an analysis of U.S. Census data for msnbc.com. The 2010 population within 50 mi was 546,292, an increase of 15.0 percent since 2000. Cities within 50 miles include Fulton (11 miles to city center), Jefferson City (26 miles to city center), and Columbia (32 miles to city center).

Seismic risk
In August 2010, the Nuclear Regulatory Commission's estimated that the annual chance that an earthquake might damage the core at Callaway was 1 in 500,000, the lowest probability of any U.S. reactor.