The Callaway Plant is a nuclear power plant located on a 5,228-acre (2,116 ha) site in Callaway County, Missouri, near Fulton, Missouri. It began operating on December 19, 1984. The plant, which is the state's only commercial nuclear unit, has one 1,190-megawatt Westinghouse four-loop pressurized water reactor and a General Electric turbine-generator. It is owned by the Ameren Corporation and operated by subsidiary Ameren Missouri.