Hi, As far as i know, when Co-59 is bombarded with neutron inside the reactor core then Co-60 is produced. What i want to know that what is the origin of the Co-59. Is it one of the products of nuclear fission? if it is so, can you show me the reaction of it. Or is it already exist in the fuel? Since co-59 is a stable isotope, it might be found in the uranium ore and during the enrichment process it may not be extracted.. Thank you in advance..