Nuclear power plant

A nuclear power plant (NPP),^[1] 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 September 2023^[update], the International Atomic Energy Agency reported that there were 410 nuclear power reactors in operation in 32 countries around the world, and 57 nuclear power reactors under construction.^[2][3][4]

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.^{[citation needed]} 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.

Building a nuclear power plant often spans five to ten years, which can accrue significant financial costs, depending on how the initial investments are financed.^[5] Because of this high construction cost and lower operations, maintenance, and fuel costs, nuclear plants are usually used for base load generation, because this maximizes the hours over which the fixed cost of construction can be amortized.^[6]

Nuclear power plants have a carbon footprint comparable to that of renewable energy such as solar farms and wind farms,^[7][8] and much lower than fossil fuels such as natural gas and coal. Nuclear power plants are among the safest modes of electricity generation,^[9] comparable to solar and wind power plants.^[10]