|Fig. 1: Ginna nuclear power plant (Source: Wikimedia Commons)|
The Robert Emmet Ginna nuclear power plant, shown in Fig. 1 and commonly known as simply "Ginna", is a single unit nuclear power plant located on 426 acres along the south shore of Lake Ontario in Ontario, New York. It first began generating electricity in June 1970, making it one of the oldest operational nuclear power plants in the United States. Further, as of the October 2016 shutdown of the Fort Calhoun Nuclear Generating Station, Ginna is the smallest operational nuclear power plant in the United States. It contains only one 582 megawatt Westinghouse 2-Loop pressurized water reactor (PWR). Ginna is currently owned and operated by the Exelon Corporation, a Fortune 100 energy company headquartered in Chicago, Illinois.
The plant is named after Robert Emmett Ginna, a longtime official of Rochester Gas and Electric Corporation who became the company's chief executive and chairman in 1957. Mr. Ginna was an early champion of the use of nuclear power, helping to build some of the first nuclear power plants in the United States. He also played a role in persuading the United States government to modify the Atomic Energy Act of 1954 to permit research into utilizing nuclear energy for electricity production. Mr. Ginna retired in 1968, roughly two years before the Ginna plant was commissioned. 
Rochester Gas and Electric constructed the Ginna plant in 1966 - a project that cost roughly $75 million. The company continued to own and operate Ginna for over 30 years, making it the last of New York state's six nuclear power plants to be sold by the utility company that built it. The most notable event at Ginna during Rochester's ownership was a nuclear accident in January 1982, which occurred when a steam generator tube abruptly ruptured. The rupture left five feet of radioactive water on the floor of the building housing the reactor, a small amount of which was turned to radioactive steam by the generator and subsequently leaked into the atmosphere. Although a site emergency was declared, radiation levels in the surrounding area remained well within tolerable levels, reportedly peaking at about 10 millirems per hour. 
In 2004, Rochester sold Ginna to the Constellation Energy Group, which acquired the plant for approximately $401 million. At the time of the acquisition, Constellation Energy also owned and operated two other nuclear power plants: Calvert Cliffs (Lusby, Maryland) and Nine Mile Point (Scriba, New York). The Constellation Energy Group merged with Exelon in 2012, and in 2014 the Nuclear Regulatory Commission (NRC) approved a license transfer that officially made Ginna part of Exelon's nuclear fleet.
Ginna is a two-loop, pressurized water reactor manufactured by the Westinghouse Electric Corporation. Pressurized water reactors are by far the most widely used type of reactor for power generation. These reactors work by using uranium as fuel to create heat in the reactor vessel. Pressurized water is then pumped through the reactor and carries the heat to the steam generator. The steam produced by the steam generator is raised to the main turbine, which ultimately produces electricity. 
In 1996, Rochester Gas and Electric installed two Babcock & Wilson steam generators to replace Ginna's original Westinghouse units. The cost of this replacement was estimated at $115 million. The rationale behind this project was detailed in Rochester Gas & Electric's 1992 Integrated Resource Plan, which explained that replacing the steam generators would reduce annual steam generator repair costs by about $3.4 million.  Years later, this project was a significant factor in the NRC's 2004 decision to extend Ginna's licensed life to 2029. 
The new steam generators also helped Constellation Energy obtain permission to increase Ginna's power output from 495 megawatts to 580. The plant was originally rated at 475 megawatts when it entered service.  By typical estimates, Ginna can provide enough electricity to power roughly 500 homes.
© Chris Sebastian. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 A. Salpukas, "Robert Ginna, 94, A Champion Of Nuclear Power," New York Times, 19 May 96.
 M. Coakley, "Nuclear Leak Peril Discounted," Chicago Tribune, 26 Jan 82.
 "Nuclear Reactor Types," Institution of Electrical Engineers, November 2005.
 K. C. Wade, "Steam Generator Degradation and Its Impact on Continued Operation of Pressurized Water Reactors in the United States," U.S. Energy Information Administration, August 1995.
 M. V. Bonaca, "Report on the Safety Aspects of the License Renewal Application for the R. E. Ginna Nuclear Power Plant," U.S. Advisory Committee on Reactor Safeguards, ACRSR-2073, 23 Apr 04.
 M. L. Wald, "Rochester Utility Sells Nuclear Power Station," New York Times, 26 Nov 03.