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US Nuclear Power Plants

General U.S. Nuclear Info

U.S. electricity from nuclear energy in 2012: 19.0 percent, with 769.3 billion kilowatt-hours generated. 

Number of states with operating reactors: 31, including seven states where nuclear makes up the largest percentage of the electricity generated.

Nuclear industry capacity factor (2012): 86 percent.

Average refueling outage duration (2012): 46 days.

Nuclear safety performance: 

U.S. Nuclear Plant Stats

Number of operating reactors: 100, with 35 boiling water reactors (BWRs) and 65 pressurized water reactors (PWRs).

Longest operating period between refueling outages: LaSalle 1 (Illinois); 739 days; February 2006.

Most electricity generated in a year: 11.8 billion kilowatt-hours at South Texas Project 2 in Texas in 2007.

Largest U.S. nuclear plant: Palo Verde (Arizona), three reactors at 1,311; 1,314; and 1,312 megawatts each, for a total of 3,937 megawatts.

Smallest nuclear plant: Fort Calhoun (Nebraska), one reactor at 478 megawatts.

Newest nuclear plant: Watts Bar 1 (Tennessee), operating license issued June 1996.

Oldest operating nuclear plant: Oyster Creek (New Jersey), operating license issued April 1969.

Nuclear plants under construction: Five, including Summer 2 and 3 (South Carolina); Vogtle 3 and 4 (Georgia); Watts Bar 2 (Tennessee).

Nuclear plant sales: Ownership shares of all or part of 30 nuclear units have been sold since 1999.

License renewal: 73 reactors have received 20-year license renewals to operate for a total of 60 years, 30 reactors have applied for or announced intentions to renew their licenses for another 20 years.

Nuclear power uprates: More than 6,900 megawatts of power uprates have been approved by the NRC since 1977. That is the equivalent of adding seven reactors to the electric grid.

Amount of electricity generated by a 1,000-megawatt reactor at 90 percent capacity factor in one year: 7.9 billion kilowatt-hours—enough to supply electricity for 690,000 households. If generated by other fuel sources, it would require: 

  • Oil: 13.7 million barrels – 1 barrel yields 576 kWh
  • Coal: 3.4 million short tons – 1 ton yields 2,297 kWh
  • Natural Gas: 65.8 billion cubic feet – 100 cubic feet yields 12 kWh

(based on average conversion rates from the Energy Information Administration)

First commercial nuclear plant decommissioned: Shippingport in Pennsylvania began operation in December 1957, shut down in 1982.

U.S. Nuclear Electric Companies

Nuclear plant owners: 81

Nuclear plant operators: 32

Mergers and Acquisitions:

  • Duke Energy merged with Progress Energy in July 2012. The merged company is called Duke Energy and includes Progress Energy’s ownership of five reactors: Brunswick 1 and 2, Crystal River 3, Robinson and Shearon Harris. 
  • Exelon Corporation merged with Constellation Energy in March 2012. The merged company is called Exelon Corporation.  As a result of this transaction, Exelon acquired Constellation's 50.01 percent ownership of Constellation Energy Nuclear Group (CENG), which operates five nuclear plants (Calvert Cliffs 1 & 2, Ginna, Nine Mile Point 1 & 2). EDF owns the remaining 49.99 percent of CENG.
  • TXU Corp./Texas Energy Future Holdings Limited Partnership (TEF), October 2007, 2 reactors total; TXU Corp's new name is Energy Future Holdings Corp. The power generation entity under the merged company is Luminant, which owns and operates the two reactors at Comanche Peak.
  • NRG Energy Inc. purchased Texas Genco LLC in February 2006. They own and operate the two reactors total at South Texas Project.
  • Exelon purchased British Energy's 50 percent interest in AmerGen in December 2003 to operate three reactors: Clinton, Oyster Creek and Three Mile Island.


  • Nuclear Management Co. was formed in February 1999 to operate six plants: Duane Arnold (Iowa), Point Beach (Wis.), Kewaunee (Wis.), Prairie Island (Minn.), Monticello (Minn.) and Palisades (Mich.) Since then, FPL Group (now called NextEra Energy Inc.) acquired and now owns Duane Arnold and Point Beach, operating them through a subsidiary, NextEra Energy Resources LLC. Dominion owns Kewaunee (now shutdown), and Entergy owns and operates Palisades. Xcel Energy's subsidiary, Northern States Power Co., operates Prairie Island and Monticello.