Zirconium-93

⁹³Zr is a radioisotope of zirconium with a half life of 1.53 million years, decaying with a low-energy beta particle to Niobium-93m, which decays with a halflife of 14 years and a low-energy gamma ray to ordinary ⁹³Nb. It is one of only 7 long-lived fission products. The low specific activity and low energy of its radiations limit the radioactive hazards of this isotope.

Nuclear fission produces it at a fission yield of 6.2956%, on a par with the other most abundant fission products. Nuclear reactors usually contain large amounts of zirconium as fuel rod cladding (see Zircaloy), and neutron irradiation of ⁹²Zr also produces some ⁹³Zr, though this is limited by ⁹²Zr's low neutron capture cross section of 0.22 barns.

⁹³Zr also has a low neutron capture cross section of 2.70 barns. Most fission zirconium consists of other isotopes; the other isotope with a significant neutron absorption cross section is ⁹¹Zr with a cross section of 1.24 barns. ⁹³Zr is a less attractive candidate for disposal by nuclear transmutation than are Tc-99 and I-129. Mobility in soil is relatively low, so that geological disposal may be an adequate solution.

ee also

*Isotopes of zirconium
* [http://www.ead.anl.gov/pub/doc/zirconium.pdf ANL fact sheet]