Top Five Nations Dominate 71% Of Global Nuclear Power Capacity

Five countries—United States, France, China, Russia, and South Korea—together account for more than two-thirds of the world’s total nuclear electricity generation capacity, according to International Atomic Energy Agency (IAEA) data as of June 2025. These nations hold 71% of global nuclear capacity, with the United States leading, followed by France, China, Russia, and South Korea. Worldwide, 416 nuclear power reactors operate in 31 countries, with a combined net generating capacity of 376 gigawatts (GW).

The United States began commercial nuclear power generation in the late 1950s with the Shippingport Atomic Power Station in Pennsylvania. Most of its current operating capacity was built between 1967 and 1990. Today, the U.S. operates 94 nuclear reactors, making it the world’s largest producer of nuclear electricity. In 2024, nuclear power contributed 782 gigawatthours (GWh), or 19% of U.S. electricity generation. In 2023, the U.S. share of global nuclear electricity was 30%. The country’s nuclear fleet operates at a high capacity factor of 92% due to improved efficiency in managing both planned and unplanned outages.

France ranks second globally and first in Europe in nuclear capacity, with 57 reactors totaling 63 GW. In 2023, its nuclear plants generated over 320 GWh, which accounted for nearly 65% of the country’s total electricity. Following the global oil crisis in the early 1970s, France rapidly expanded its nuclear program, building 52 reactors between 1975 and 1990 to strengthen energy security.

China has the fastest-growing nuclear sector in the world, commissioning 57 reactors since 1991. According to IAEA, 28 more reactors with a combined capacity of 30 GW are under construction, and when completed, China’s total nuclear capacity will surpass France’s. In 2023, China’s operating reactors produced over 433 GWh, representing about 5% of its total electricity generation. China has acquired nuclear technology from several countries, including France, Canada, and Russia, and has recently adapted the U.S.-based Westinghouse AP1000 reactor design into its own CAP1000 model.

Russia operates 36 nuclear reactors with a total capacity of 27 GW, and another four reactors totaling 4 GW are being built. Rosatom, the state-owned nuclear energy corporation, is modernizing the reactor fleet, replacing older RBMK light-water graphite-cooled units with more efficient VVER-1000 and VVER-1200 light-water designs. Russia is currently the world’s largest exporter of nuclear power technology.

South Korea’s nuclear program, which began in the 1970s, is a key part of its energy security strategy, aimed at reducing dependence on imported fossil fuels. The country operates 26 reactors, with two more under construction. Korea Hydro & Nuclear Power, a state-backed entity, is active internationally, having built the Barakah nuclear plant in the United Arab Emirates and secured the vendor role for the Dukovany plant expansion in the Czech Republic.

These five countries remain central to the global nuclear power landscape, leading in installed capacity, technological development, and international collaboration, while also pursuing strategies shaped by domestic energy needs and global market opportunities.