Making of fission 99Mo from LEU silicide(s): A radiochemists' view

The present-day industrial scale production of 99Mo is fission based and involves thermal-neutron irradiation in research reactors of highly enriched uranium (HEU, > 20 % 235U) containing targets, followed by radiochemical processing of the irradiated targets resulting in the final product: a 99Mo containing chemical compound of molybdenum. In 1978 a program (RERTR) was started to develop a substitute for HEU reactor fuel i.e. a low enriched uranium (LEU, < 20 % 235U) one. In the wake of that program studies were undertaken to convert HEU into LEU based 99Mo production. Both new targets and radiochemical treatments leading to 99Mo compounds were proposed. One of these targets is based on LEU silicide, U3Si2. Present paper aims at comparing LEU U3Si2 and LEU U3Si with another LEU target i.e. target material and arriving at some preferences pertaining to 99Mo production. (author)