Fission products

residual radioactive material following a nuclear blast

Caesium-137 (), cesium-137 (US), or radiocaesium, is a radioactive isotope of caesium that is formed as one of the more common fission products by the nuclear fission of uranium-235 and other fissionable isotopes in nuclear reactors and nuclear weapons. Trace quantities also originate from spontaneous fission ofuranium-238. It is among the most problematic of the short-to-medium-lifetime fission products. Caesium has a relatively low boiling point of and easily becomes volatile when released suddenly at high temperature, as in the case of the nuclear accident and with nuclear explosions, and c

Iodine-131 (131I, I-131) is a radioisotope of iodine discovered by Glenn Seaborg and John Livingood in 1938 at the University of California, Berkeley. It has a radioactive decay half-life of about eight days. It is associated with nuclear energy, medical diagnostic and treatment procedures, and natural gas production. It also plays a major role as a radioactive isotope present in nuclear fission products, and was a significant contributor to the health hazards from open-air atomic bomb testing in the 1950s, and from the Chernobyl disaster, as well as being a large fraction of the contamination

Strontium-90 () is a radioactive isotope of strontium produced by nuclear fission, with a half-life of 28.91years. It undergoes β decay into with a decay energy of 0.546MeV. has applications in medicine and industry and is an isotope of concern in fallout from nuclear weapons, nuclear weapons testing, and nuclear accidents.

product of nuclear fission

Xenon-135 (135Xe) is an unstable isotope of xenon with a half-life of 9.14 hours, decaying to long-lived caesium-135.

Krypton-85 (85Kr) is a radioisotope of krypton, distributed throughout the atmosphere and presently forming about 15 ppt of atmospheric krypton on average.

Iodine-129 (129I) is a long-lived radioisotope of iodine that occurs naturally, but is of greater interest as a man-made nuclear fission product, where it is a potential radiological contaminant. The same contamination, though, together with its long half-life, make it serve as a tracer of environmental processes that have nothing to do with its creation.

Technetium-99 (99Tc) is an isotope of technetium that decays with a half-life of 211,000 years to stable ruthenium-99, emitting beta particles, but effectively no gamma rays. It is the most significant long-lived fission product of uranium fission, and the largest single contributor to the long-lived radioactivity of nuclear waste. Technetium-99 has a fission product yield of 6.0507% for thermal neutron fission of uranium-235.

Critical radionuclides for the long-term safety of nuclear waste repositories

Selenium-79 is a radioisotope of selenium present in spent nuclear fuel and the wastes resulting from reprocessing this fuel. It is one of only seven long-lived fission products. Its fission yield is low (about 0.04%), as it is near the lower end of the mass range for fission products. Its half-life has been variously reported as 650,000 years, 65,000 years, 1.13 million years, 480,000 years, 295,000 years, 377,000 years, and most recently and the best current value, 327,000 years.