fissiotuote

A fissiotuote, or fission product, is any fragment produced when a heavy atomic nucleus undergoes fission. In a typical fission event, a heavy nucleus such as uranium-235 or plutonium-239 splits into two lighter nuclei, called fission fragments, and may emit prompt neutrons and gamma rays. Most fission products are radioactive and decay to more stable isotopes through beta decay and sometimes gamma emission.

Fission yields are uneven; the two fragments tend to be in the range around mass numbers 95 and 135. Hundreds of different isotopes can be produced, including iodine-131, cesium-137, strontium-90, xenon-133, ruthenium-103, and others. The exact mix depends on the fissile material and the energy of the fission event.

Decay and heat: The fission products contribute to decay heat in cooled spent fuel and to residual radioactivity in the environment after a release. Half-lives vary widely from milliseconds to years; short-lived isotopes dominate early radiological hazards, while long-lived isotopes persist for decades.

Impacts and safety: Containment of fission products is central to nuclear safety. Some isotopes, such as iodine-131, tend to accumulate in specific organs (for example, the thyroid), while others pose external gamma exposure. Management focuses on shielding, containment, cooling, and long-term waste handling.

Applications and regulation: Some fission products have beneficial uses, such as medical isotopes produced in reactors. Most fission products within spent fuel are managed as high-level radioactive waste, requiring cooling, encapsulation, and planned geological disposal. See also: Nuclear fission, Decay heat, Radioactive waste.