Nuclear power generation in the United States

The United States is one of the world’s largest producers and consumers of energy. The country draws its electricity from a variety of sources, including fossil fuels, nuclear power and renewables. In 2021, the breakdown of electricity production was as follows: 40% natural gas, 19% coal, 20% renewables (hydro, wind, solar and others) and 20% nuclear power [1].

The innovative power plant and reactor projects currently under development demonstrate the country’s commitment to innovation in the nuclear sector. Third- and fourth-generation reactors, such as EPRs, RMAs, RSFs and RNRs, offer promising prospects for the future of nuclear power generation in the United States. They are designed to be safer, more efficient and more sustainable than reactors currently in service. As these technologies advance, they could play a crucial role in diversifying the US energy mix and reducing the country’s carbon footprint.

History of nuclear power generation in the United States

The history of nuclear power in the United States dates back to the 1940s and 1950s, when the country developed the first nuclear weapons and experimental reactors. The first commercial nuclear reactor, Shippingport Atomic Power Station, was commissioned in 1958 in Pennsylvania [2]. Since then, nuclear power has grown significantly, with a period of rapid construction between the 1960s and 1980s.

In 1979, the Three Mile Island nuclear accident in Pennsylvania raised concerns about the safety of nuclear power plants and led to stricter regulations. Despite this, nuclear power generation continued to grow, peaking in 1990 with a generating capacity of around 100 gigawatts (GW) [3].

Since the early 1990s, construction of new nuclear power plants has slowed, mainly due to increased competition from cheaper energy sources and environmental concerns. However, nuclear power generation remains stable, with 93 reactors in operation in 2021, spread across 28 states [4].

Nuclear reactor technologies used in the USA

The majority of nuclear reactors in operation in the United States are pressurized water reactors (PWRs) or boiling water reactors (BWRs) [5]. These second-generation reactors use enriched uranium as fuel and water as moderator and coolant.

PWRs account for around two-thirds of the reactors in operation in the United States [5]. In a PWR, water is kept under high pressure to prevent it turning to steam. The heat produced by nuclear fission is transferred to a secondary circuit via a steam generator, where it is converted into steam to drive a turbine and generate electricity.

BWRs, meanwhile, account for around a third of the reactors operating in the U.S [5]. Unlike PWRs, BWRs allow water to be converted to steam directly in the reactor core. The steam is then routed to a turbine to generate electricity.

Innovative power plant and reactor projects

The United States is currently developing third- and fourth-generation nuclear reactor technologies to improve the safety, efficiency and sustainability of nuclear power generation. Here are a few notable projects:

1. Advanced Pressurized Water Reactors (EPR): These third-generation reactors are designed to be safer and more efficient than traditional PWRs. Westinghouse Electric Company is developing the AP1000, an EPR with a capacity of 1,100 electrical megawatts (MWe) [6]. Two AP1000 units are currently under construction at the Vogtle nuclear power plant in Georgia, with commissioning scheduled for 2022 and 2023 [7].
2. Advanced Modular Reactors (AMRs): AMRs are small nuclear reactors (below 300 MWe) designed to be flexible, safe and economical. NuScale Power, a US company, is developing a 77 MWe AMR using light water as moderator and coolant [8]. NuScale’s first commercial project, the Utah Associated Municipal Power Systems (UAMPS) nuclear power plant, is scheduled to be operational in 2029 [9].
3. Molten-salt reactors (MSRs): RSFs are fourth-generation reactors that use molten salts as fuel and coolant. They offer advantages in terms of safety, efficiency and waste management. Several U.S. companies, including TerraPower and Southern Company, are collaborating to develop a prototype RSF by 2030 [10].
4. Fast breeder reactors (FBRs): FBRs are fourth-generation reactors designed to make more efficient use of nuclear fuel and reduce the amount of radioactive waste. General Electric and Hitachi are jointly developing the PRISM, a 311 MWe sodium-cooled fast breeder reactor [11]. No timetable has yet been set for the construction of a commercial PRISM plant.

Nuclear power plants in the USA

Countries producing nuclear power

Sources :

• [1] U.S. Energy Information Administration (EIA). (2021). Electric Power Monthly. https://www. eia.gov/electricity/monthly/
• [2] U.S. Department of Energy (DOE). (n.d.). Shippingport Atomic Power Station. https://www. energy.gov/ne/shippingport-atomic-power-station
• [3] World Nuclear Association. (2021). Nuclear Power in the USA. https://www.world-nuclear.org/information-library/country-profiles/countries-t-z/usa-nuclear-power.aspx
• [4] U.S. Energy Information Administration (EIA). (2021). How many nuclear power plants are in the United States, and where are they located? https://www.eia.gov/tools/faqs/faq.php?id=207&t=3
• [5] U.S. Nuclear Regulatory Commission (NRC). (2021). Reactor Types. https://www. nrc.gov/reactors/reactor-types.html
• [6] Westinghouse Electric Company. (n.d.). AP1000® Pressurized Water Reactor. https://www.westinghousenuclear.com/new-plants/ap1000-pwr
• [7] Georgia Power. (2021). Plant Vogtle Units 3 and 4. https://www. georgiapower.com/company/plant-vogtle.html
• [8] NuScale Power. (n.d.). NuScale’s Technology. https://www. nuscalepower.com/technology
• [9] NuScale Power. (2021). Carbon Free Power Project. https://www. nuscalepower.com/projects/carbon-free-power-project
• [10] Southern Company. 2021. Advanced Reactor Development. https://www. southerncompany.com/what-doing/energy-innovation/advanced-reactor-development.html
• [11] GE Hitachi Nuclear Energy. (n.d.). PRISM. https://nuclear.gepower.com/build-a-plant/products/nuclear-power-plants-overview/prism