Nuclear energy, energy that is released in significant amounts in processes that affect atomic nuclei, the dense cores of atoms. One method of releasing nuclear energy is by controlled nuclear fission, used in nuclear power plants around the world. Another method, controlled nuclear fusion, has not yet been perfected. Nuclear bolsters energy security and contributes to addressing climate concerns. In 2023, more than 410 reactors were in operation in over 30 countries, with nuclear energy providing 9% of global electricity supply. Nuclear was the second-largest source of low-emissions electricity after hydropower, producing 20% more than wind and 70% more than solar PV, and also providing heat for industry, district heating and desalination in several countries. Since 1971, nuclear energy has avoided 72 Gt ... Nuclear power plants must be protected since the material inside a nuclear power plant can be used by terrorists. Nuclear power plants have armed guards, many different kinds of fences and barriers, cameras and many controls on who can come into the plant. The first commercial nuclear power stations started operation in the 1950s. Nuclear energy now provides about 9% of the world's electricity from about 440 power reactors. 31 countries generate electricity from nuclear energy. Nuclear provides about one-quarter of the world’s low-carbon electricity.
