The United States operated 96 commercial nuclear reactors at 57 power plants across 28 states as of March 2026, according to industry statistics. Together the fleet provides a combined net summer electricity generation capacity of 98,441 megawatts, making nuclear the largest source of carbon-free electricity in the country.

Reliability remains the fleet's defining feature. The average annual capacity factor for U.S. nuclear plants reached 91 percent in 2025, higher than any other type of power plant. By comparison, the fleet operated at 92 percent in 2024. Capacity factor measures how much electricity a plant actually produces relative to its maximum possible output, and nuclear's consistently high figure reflects the around-the-clock operation that distinguishes it from weather-dependent sources.

That steady output translates into a meaningful share of the grid. Nuclear power accounts for roughly 19 percent of total U.S. electricity generation, a contribution it has maintained for years despite a relatively flat reactor count. The combination of high capacity factors and long operating licenses has kept nuclear central to the U.S. power mix even as the grid adds large amounts of solar, wind, and battery storage. License renewals and uprates are extending the fleet's productive life further into the future.

Source: Nuclear Energy Institute - https://www.nei.org/resources/statistics/us-nuclear-generating-statistics