There are 57 nuclear power plants operating in the United States
Electricity generation from commercial nuclear power plants in the United States began in 1958. As of March 2026, the United States had 96 operating commercial nuclear reactors at 57 nuclear power plants in 28 states. The average age of these nuclear reactors is about 44 years old. The oldest operating reactor, Nine Mile Point Unit 1 in New York, began commercial operation in December 1969. The newest reactor to enter commercial service is Unit 4 at the Alvin W. Vogtle Electric Generating Plant in Georgia, which began commercial operation in April 2024.
The number of operating U.S. nuclear reactors and their combined net summer electricity generation capacity was 98,441 megawatts. Although the number of reactors has declined since 2012, power plant uprates—modifications to increase capacity—at individual nuclear power plants have made it possible for the entire operating nuclear reactor fleet to maintain high capacity-utilization rates (or capacity factors).
Nuclear reactors are decommissioned after they are retired from commercial service. According to the U.S. Nuclear Regulatory Commission, 19 commercial nuclear power reactors at 15 sites are in various stages of decommissioning.
28 states have at least one commercial nuclear reactor
Most U.S. commercial nuclear power reactors are located east of the Mississippi River. Illinois has more reactors than any state (11 reactors at 6 plants), and at the end of 2025, it had the largest total nuclear net summer electricity generation capacity, at about 11,592 megawatts (MW). The Grand Gulf Nuclear Station in Port Gibson, Mississippi, has the largest U.S. nuclear reactor, with a net summer electricity generation capacity of about 1,400 MW. The two smallest operating reactors, each with a net summer generation capacity of about 520 MW, are at the Prairie Island nuclear plant in Red Wing, Minnesota.
Many nuclear power plants have more than one reactor
The term power plant refers to an entire facility. A power plant may contain nuclear as well as non-nuclear electricity generating units. Each nuclear reactor located at a commercial nuclear power plant is unique and has its own personnel and equipment. The reactor provides heat to make steam, which drives a turbine that drives the generator that produces electricity.
The number of reactors at U.S. nuclear power plants varies. As of March 2026:
- 22 U.S. nuclear plants had one reactor
- 31 had two reactors
- 3 had three reactors
- 1 had four reactors
Some foreign nuclear power plants have as many as eight reactors.
Nuclear power plants are generally used more intensively than other power plants
For cost and technical reasons, nuclear power plants are generally used more intensively than coal- or natural gas-fired power plants, as measured by electric generation capacity factor. The average annual capacity factor for nuclear power plants in 2025 was 91%, which was higher than the capacity factors for other types of power plants.
Recent U.S. nuclear construction activity welcomes another reactor
The new reactor, Unit 4, reached completion at the Vogtle nuclear plant in Georgia in early 2024. Vogtle is the largest nuclear power plant in the United States, with four reactors and a total 4,530 MW net summer electricity generation capacity.
The NRC issues license applications for new reactors in various stages of review. The NRC application review process can take up to five years to complete. Under current licensing regulations, a company that seeks to build a new reactor can use reactor designs that the NRC has approved. NRC's design certification is independent of its approval of applications to construct or operate new nuclear power plants. When the applicant uses an NRC-certified reactor design, all safety issues related to the design have been resolved, and the focus of NRC's review is the quality of construction. Construction of a nuclear power plant may take five years or more.
EIA projects in the Annual Energy Outlook 2026 Counterfactual Baseline case that total nuclear net summer electricity generation capacity will remain relatively stable, slightly increasing by 99,000 MW in 2050. However, the share of nuclear generation declines from 17% in 2025 to between 12% and 15% by 2050.