90 Zr
89.9047026 (26)
51.45 (2)
oxide
84 – 99+
91 Zr
90.9056439 (26)
11.22 (2)
oxide
44 – 96+
92 Zr
91.9050386 (26)
17.15 (1)
oxide, metal
80 – 97+
94 Zr
93.9063148 (28)
17.38 (2)
oxide, metal
73 – 98+
96 Zr
95.908275 (4)
2.80 (1)
oxide
53 – 86+
Zirconium has five stable isotopes, of which a few are used for the production of radioisotopes. Although radioactive Zr-95 is a fission product, it can also produced by neutron irradiation of Zr-94. Zr-96 has been used for the production of the radioisotope Zr-97. Zr-90 can be used for the production of the PET isotope Nb-90. Finally, Zr-90 has been proposed for cladding in nuclear fuel. The use of Zr-90 would lower even further the already low neutron absorption cross section of natural Zr that is currently used as fuel cladding.