Nuclear power in France in the context of "Terawatt-hour"

A nuclear power plant (NPP), also known as a nuclear power station (NPS), nuclear generating station (NGS) or atomic power station (APS) is a thermal power station in which the heat source is a nuclear reactor. As is typical of thermal power stations, heat is used to generate steam that drives a steam turbine connected to a generator that produces electricity. As of October 2025, the International Atomic Energy Agency reported that there were 416 nuclear power reactors in operation in 31 countries around the world, and 62 nuclear power reactors under construction.

Most nuclear power plants use thermal reactors with enriched uranium in a once-through fuel cycle. Fuel is removed when the percentage of neutron absorbing atoms becomes so large that a chain reaction can no longer be sustained, typically three years. It is then cooled for several years in on-site spent fuel pools before being transferred to long-term storage. The spent fuel, though low in volume, is high-level radioactive waste. While its radioactivity decreases exponentially, it must be isolated from the biosphere for hundreds of thousands of years, though newer technologies (like fast reactors) have the potential to significantly reduce this. Because the spent fuel is still mostly fissionable material, some countries (e.g. France and Russia) reprocess their spent fuel by extracting fissile and fertile elements for fabrication into new fuel, although this process is more expensive than producing new fuel from mined uranium. All reactors breed some plutonium-239, which is found in the spent fuel, and because Pu-239 is the preferred material for nuclear weapons, reprocessing is seen as a weapon proliferation risk.

Nuclear power plants operate in 31 countries and generate about a tenth of the world's electricity. Most are in Europe, North America and East Asia.The United States is the largest producer of nuclear power, while France has the largest share of electricity generated by nuclear power, at about 65%.

Some countries operated nuclear reactors in the past but currently have no operating nuclear power plants. Among them, Italy closed all of its nuclear stations by 1990 and nuclear power has since been discontinued because of the 1987 referendums. Lithuania closed its nuclear station in 2009 because it was of the dangerous RBMK reactor type. Kazakhstan phased out nuclear power in 1999 but is planning to reintroduce it possibly by 2035 under referendum. Germany operated nuclear plants since 1960 until the completion of its phaseout policy in 2023. Austria (Zwentendorf Nuclear Power Plant) and the Philippines (Bataan Nuclear Power Plant) both built a nuclear plant but never put it in use.

Ukraine operates four nuclear power plants with 15 reactors located in Volhynia and South Ukraine. The total installed nuclear power capacity is over 13 GWe, ranking 7th in the world in 2020. Energoatom, a Ukrainian state enterprise, operates all four active nuclear power stations in Ukraine.In 2019, nuclear power supplied over 20% of Ukraine's energy.

In 2021, Ukraine's nuclear reactors produced 81 TWh — over 55% of its total electricity generation, and the second-highest share in the world, behind only France. The Zaporizhzhia Nuclear Power Plant, the largest nuclear power plant in Europe, is in Ukraine.