Tin (50Sn) is the element with the greatest number of stable isotopes (ten; three of them are potentially radioactive but have not been observed to decay).
In addition, twenty-nine unstable tin isotopes are known, including tin-100 (100Sn) (discovered in 1994)[4] and tin-132 (132Sn), which are both "doubly magic".
In a normal thermal reactor, it has a very low fission product yield; thus, this isotope is not a significant contributor to nuclear waste.
While tin-126's half-life of 230,000 years translates to a low specific activity of gamma radiation, its short-lived decay products, two isomers of antimony-126, emit 17 and 40 keV gamma radiation and a 3.67 MeV beta particle on their way to stable tellurium-126, making external exposure to tin-126 a potential concern.
Thermal reactors, which make up almost all current nuclear power plants, produce it at a very low yield (0.056% for 235U), since slow neutrons almost always fission 235U or 239Pu into unequal halves.