radioactive heat

Radioactive heat is generated by the decay of radioactive isotopes. Some isotopes, like uranium-238 and thorium-232, have very long half-lives and are found naturally on Earth, contributing to the planet's internal heat. Other radioactive isotopes are produced in the atmosphere by cosmic rays, such as carbon-14 and tritium.1

In nuclear reactors, nuclear fission releases a significant amount of energy as heat almost instantaneously. The radioactive decay of fission products also generates heat, which must be managed by cooling systems to prevent the fuel from melting. This heat is then used to generate power. Radioactive decay is also a major source of heat within the Earth's interior, influencing geological processes.231