Yttrium-89
| Y | Y | Y |
The only stable yttrium isotope, 89Y, will be found with yield somewhat less than 1% in a fission product mixture which has been allowed to age for months or years, as the other isotopes have half-lives of 106.6 days or less.
90Sr decays into 90Y which is a beta emitter with a half-life of 2.67 days. 90Y is sometimes used for medical purposes and can be obtained either by the neutron activation of stable 89Y or by using a device similar to a technetium cow.
Read more about this topic: Fission Products (by Element)