In the United States, nuclear power is provided by 96 commercial reactors with a net capacity of 98gigawatts (GW), with 65pressurized water reactors and 31boiling water reactors. In 2022, they produced a total of 771.5terawatt-hours of electricity, and by 2024 nuclear energy accounted for 18.6% of the nation's total electric energy generation. In 2018, nuclear comprised nearly 50percent of US emission-free energy generation.
As of July2026, 41reactors have been permanently shut down. The United States is the world's largest producer of commercial nuclear power, and in 2013 generated 33% of the world's nuclear electricity. With the past and future scheduled plant closings, China and Russia could surpass the United States in nuclear energy production.
As of January2022, the U.S. Nuclear Regulatory Commission (NRC) had granted license renewals to a total of 94commercial reactors. In early 2014, the NRC prepared to receive the first applications of license renewal beyond 60years of reactor life as early as 2017, a process which by law requires public involvement. Licenses for 22reactors are due to expire before the end of 2029 if no renewals are granted. Pilgrim Nuclear Power Station in Massachusetts was permanently shut down on May31, 2019. Another five aging reactors were permanently closed in 2013 and 2014 before their licenses expired because of high maintenance and repair costs at a time when natural gas prices had fallen: San Onofre2 and3 in California, Crystal River3 in Florida, Vermont Yankee in Vermont, and Kewaunee in Wisconsin. In April2021, New York State permanently closed Indian Point in Buchanan, from New York City.
Most reactors began construction by 1974. But after the Three Mile Island accident in 1979 and changing economics, many planned projects were canceled. More than 100orders for nuclear power reactors, many already under construction, were canceled in the 1970s and 1980s, bankrupting some companies.
In 2006, the Brookings Institution, a public policy organization, stated that new nuclear units had not been built in the United States because of soft demand for electricity, the potential cost overruns on nuclear reactors due to regulatory issues and resulting construction delays.
There was a revival of interest in nuclear power in the 2000s, with talk of a "nuclear renaissance", supported particularly by the Nuclear Power 2010 Program. A number of applications were made, but facing economic challenges, and later in the wake of the 2011 Fukushima Daiichi nuclear disaster, most of these projects have been canceled. Up until 2013, there had also been no ground-breaking on new nuclear reactors at existing power plants since 1977. On October19, 2016, Tennessee Valley Authority's Unit2 reactor at the Watts Bar Nuclear Generating Station became the first US reactor to enter commercial operation since 1996. Then in 2012, the Nuclear Regulatory Commission approved construction of four new reactors at existing nuclear plants. Construction of the Virgil C. Summer Nuclear Generating Station Units2 and3 began on March9, 2013, but was abandoned on July31, 2017, after the reactor supplier Westinghouse filed for bankruptcy protection in March2017. On March12, 2013, construction began on the Vogtle Electric Generating Plant Units3 and4. The target in-service date for Unit3 was originally November2021. Vogtle Unit3 reached "initial criticality" and started service on July31, 2023, while Unit4 entered commercial operation in 2024. These were the first new US commercial reactors to enter operation in more than five years, with a combined gross electrical capacity of 2,500MW. In 2025, nuclear power produced 18% of the country’s electricity.
History
Emergence
Research into the peaceful uses of nuclear materials began in the United States under the auspices of the Atomic Energy Commission, created by the United States Atomic Energy Act of 1946. Medical scientists were interested in the effect of radiation upon the fast-growing cells of cancer, and materials were given to them, while the military services led research into other peaceful uses.
Power reactor research Argonne National Laboratory was assigned by the United States Atomic Energy Commission (AEC) the lead role in developing commercial nuclear energy beginning in the 1940s. Between then and the turn of the 21st century, Argonne designed, built, and operated fourteen reactors at its site southwest of Chicago, and another fourteen reactors at the National Reactor Testing Station (now Idaho National Laboratory) in Idaho. . These reactors included initial experiments and test reactors that were the progenitors of today's pressurized water reactor (including United States naval reactors), boiling water reactor, heavy-water reactor, graphite-moderated reactor, and liquid metal cooled reactor, including the EBR-1, the first reactor in the world to generate electricity. Argonne and a number of other AEC contractors built a total of 52 reactors at the National Reactor Testing Station. Two were never operated; except for the Neutron Radiography Facility, all the other reactors were shut down by 2000.
In the early afternoon of December 20, 1951, Argonne director Walter Zinn and fifteen other Argonne staff members witnessed a row of four light bulbs light up in a nondescript brick building in the eastern Idaho desert. Electricity from a generator connected to Experimental Breeder Reactor I (EBR-I) flowed through them. This was the first time that a usable amount of electrical power had ever been generated from nuclear fission. Only days afterward, the reactor produced all the electricity needed for the entire EBR complex. One ton of natural uranium can produce more than 40 gigawatt-hours of electricity—the equivalent to burning 16,000 tons of coal or 80,000 barrels of oil. More central to EBR-I's purpose than just generating electricity, however, was its role in proving that a breeder reactor could create more nuclear fuel as a byproduct than it consumed during operation. In 1953, tests verified that this was the case.
The United States Navy took leadership early in the development of nuclear power in the US, seeing the opportunity to design ships that could steam around the world at high speeds for several decades without needing to refuel, and the possibility of turning submarines into true full-time underwater vehicles. The Navy assigned then-Captain Hyman Rickover, known for his talents in electrical engineering and propulsion systems in addition to project management, to the AEC to start the Naval Reactors project. Rickover's work with the AEC led to the development of the Pressurized Water Reactor (PWR), the first naval model of which was installed in the submarine , and Rickover became known as the "Father of the Nuclear Navy." A nuclear power plant made the boat capable of operating underwater full-time, which it demonstrated by becoming the first vessel to traverse the North Pole by charting a route underneath the Polar ice cap in August 1958.
Another type of reactor called the Molten-Salt Reactor Experiment was developed at Oak Ridge National Laboratory by Alvin Weinberg in the 1960s. The reactor logged more than 13,000 hours at full power during its brief run from 1965 to 1969, and was able to be shut down and restarted. It achieved all of its objectives, demonstrating the first fission of Uranium-233 for power generation and the feasibility of liquid reactor fuel, as well as greater safety and more efficient fission processes producing less long-lived actinide waste. The molten salt program ended in 1973, with the Atomic Energy Commission deciding to focus on other designs per direction from President Richard Nixon. Both government and industry experts are now reevaluating molten salt technology as an answer to the global energy challenge because it offers modular construction opportunities, produces less long-lived waste, and does not pose the core meltdown or hydrogen explosion risks inherent to water-cooled designs.
Start of commercial nuclear power From the successful naval reactor program, plans were quickly developed for the use of reactors to generate steam to drive turbines turning generators. In April 1957, the SM-1 Nuclear Reactor in Fort Belvoir, Virginia was the first atomic power generator to go online and produce electrical energy to the U.S. power grid. On May 26, 1958, the first commercial nuclear power plant in the United States, Shippingport Atomic Power Station, was opened by President Dwight D. Eisenhower as part of his Atoms for Peace program. As nuclear power continued to grow throughout the 1960s, the Atomic Energy Commission (AEC) anticipated that more than 1,000 reactors would be operating in the United States by 2000.Parker, Larry and Holt, Mark (March 9, 2007). Nuclear power: Outlook for new U.S. reactors CRS Report for Congress. As the industry continued to expand, the AEC's development and regulatory functions were separated in 1974; the Department of Energy absorbed research and development, while the regulatory branch was spun off and turned into an independent commission known as the U.S. Nuclear Regulatory Commission (USNRC or simply NRC).
Pro-nuclear power stance
As of February 2020, Our World In Data stated that "nuclear energy and renewables are far, far safer than fossil fuels as regards human health, safety and carbon footprint," with nuclear energy resulting in 99.8% fewer deaths than brown coal; 99.7% fewer than coal; 99.6% fewer than oil; and 97.5% fewer than gas. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License.
Under President Obama, the Office of Nuclear Energy stated in January 2012 that "Nuclear power has safely, reliably, and economically contributed almost 20% of electrical generation in the United States over the past two decades. It remains the single largest contributor (more than 70%) of non-greenhouse-gas-emitting electric power generation in the United States. Domestic demand for electrical energy is expected to grow by more than 30% from 2009 to 2035. At the same time, most of the currently operating nuclear power plants will begin reaching the end of their initial 20-year extension to their original 40-year operating license, for a total of 60 years of operation." It warned that if new plants do not replace those which are retired then the total fraction of generated electrical energy from nuclear power will begin to decline.
The United States Department of Energy web site states that "nuclear power is the most reliable energy source", and to a great degree "has the highest capacity factor. Natural gas and coal capacity factors are generally lower due to routine maintenance and/or refueling at these facilities while renewable plants are considered intermittent or variable sources and are mostly limited by a lack of fuel (i.e. wind, sun, or water)." Nuclear is the largest source of clean power in the United States, generating more than 800 billion kilowatt-hours of electricity each year and producing more than half of the nation's emissions-free electricity. This avoids more than 470 million metric tons of carbon each year, which is the equivalent of removing 100 million cars off of the road. In 2019, nuclear plants operated at full power more than 93% of the time, making it the most reliable energy source on the power grid. The Department of Energy and its national labs are working with industry to develop new reactors and fuels that will increase the overall performance of nuclear technologies and reduce the amount of nuclear waste that is produced.
Advanced nuclear reactors "that are smaller, safer, and more efficient at half the construction cost of today's reactors" were part of Joe Biden's clean energy proposals when he was candidate for U.S. President prior to 2021.
Opposition to nuclear power