Nuclear energy is used by 32 countries operating a combined 413 reactors, with a total installed capacity of about 377 gigawatts. The biggest users are a handful of nations that together dominate global output: the United States, China, France, South Korea, and Russia account for roughly 71% of the world’s nuclear generation capacity. But nuclear power isn’t just for governments and utilities. It extends into heavy industry, military applications, and even paper mills.
Countries That Rely on Nuclear Power
The United States is the world’s largest nuclear energy user by a wide margin. Its fleet of 111 reactors produced about 30% of all nuclear electricity generated globally in 2023, and nuclear power supplied 19% of U.S. electricity in 2024. France comes next in terms of dependence: nuclear accounted for nearly 65% of France’s total electricity production in 2024, making it the most nuclear-reliant major economy on earth. China ranks third in total output, with its reactors generating over 433 gigawatt-hours in 2023, though that represented only about 5% of China’s enormous electricity demand.
Beyond those three, significant nuclear fleets operate in South Korea, Russia, Canada, Ukraine, the United Kingdom, Japan, and India. The split between these countries reflects different national strategies. France built its nuclear fleet rapidly in the 1970s and 1980s to reduce oil dependence. The U.S. built most of its plants during the same era but hasn’t added capacity at the same pace since. China, by contrast, is in the middle of the largest nuclear construction boom in history.
China’s Rapid Expansion
China currently operates 58 reactors with about 60 gigawatts of gross capacity, and another 33 reactors are under construction, adding 35 gigawatts more. Between 2019 and 2024, the Chinese government approved 46 new reactors. In April 2025, another ten were greenlit. The China Nuclear Energy Association projects the country will reach 110 gigawatts of nuclear capacity by 2030 and 150 gigawatts by 2035, which would make it the world’s largest nuclear power producer within a decade.
U.S. States With the Highest Nuclear Share
Within the United States, 30 states have operating commercial nuclear plants, but nuclear dependence varies dramatically by state. Twelve states get more than 30% of their electricity from nuclear power. Three states exceed 50%: New Hampshire leads at 61%, followed by South Carolina at 56% and Illinois at 54%. Illinois also has the most reactors of any state (11) and the most nuclear generating capacity at 11.6 gigawatts.
These numbers matter because they show that nuclear energy isn’t spread evenly across the country. In some states it’s the backbone of the grid, while in others it plays no role at all.
Private Companies That Operate Nuclear Plants
Most nuclear reactors in the U.S. are owned and operated by private utilities, not the government. Constellation Nuclear (formerly part of Exelon) is the largest nuclear operator in the country, running plants across multiple states including Braidwood, Byron, Calvert Cliffs, Dresden, LaSalle, Limerick, and Peach Bottom. Duke Energy is another major operator, with plants like Brunswick, Catawba, Harris, McGuire, and Oconee spread across the Carolinas.
In France, the picture is different. Électricité de France (EDF), a state-controlled utility, operates virtually all of the country’s nuclear fleet. South Korea’s plants are run by Korea Hydro and Nuclear Power, a government subsidiary. So while the U.S. model leans heavily on private ownership, most other nuclear nations keep their plants under some degree of state control.
Industries That Use Nuclear Energy Directly
Electricity generation gets the most attention, but nuclear energy also serves heavy industry. The concept isn’t new. In 1964, Norway’s Halden reactor was specifically sited to provide process heat to a nearby paper mill. In Switzerland, the Gösgen reactor still supplies process steam to two neighboring paper mills today.
Research from Idaho National Laboratory identifies several industries that could decarbonize using nuclear heat: petroleum refining, fertilizer and ammonia production, iron and steel manufacturing, methanol production, and chemical processing. The connection point is often hydrogen. Nuclear plants can generate clean hydrogen, which then feeds into refining, ammonia synthesis, and other chemical processes that currently rely on natural gas. Pulp and paper mills can use nuclear process steam directly, while steel and cement operations need the high-temperature heat that advanced reactor designs are being built to provide.
Military and Naval Applications
Nuclear energy powers more than civilian grids. The U.S. Navy operates roughly 80 nuclear-powered vessels, including all of its submarines and aircraft carriers. France, the United Kingdom, Russia, China, and India also operate nuclear-powered naval fleets. These reactors are compact, designed to run for years without refueling, and allow submarines to stay submerged for months at a time. Naval reactors were, in fact, the original application of nuclear fission technology. The first nuclear-powered submarine, USS Nautilus, launched in 1954, predating most commercial nuclear power plants.
Small Modular Reactors and New Users
A new category of nuclear technology is expanding the list of potential users. Small modular reactors, or SMRs, are compact designs that can be factory-built and deployed to remote locations, industrial sites, or small grids where a full-scale plant wouldn’t make sense. Four SMRs are currently in advanced stages of construction in Argentina, China, and Russia, and several countries that have never used nuclear power before are exploring SMR projects.
The appeal for new users is flexibility. An SMR can be sized to power a mining operation, a military base, a data center, or a small island nation. Tech companies including Google, Microsoft, and Amazon have announced agreements or intentions to source nuclear power for their data centers, driven by the enormous and growing electricity demand of artificial intelligence workloads. This represents a shift: for the first time, major private technology firms are becoming direct customers of nuclear energy rather than simply drawing from the grid.