Development of a 37-element fuel bundle for the production of molybdenum-99 in CANDU power reactors.

Abstract

In this study, the potential use of CANDU power reactors for the production of Mo-99 is assessed. Five different modifications of a 37-element fuel bundle that could be used for the production of Mo-99 in existing CANDU type power reactors are explored. Since Mo-99 is generated by the fission of U-235 with a fission yield of 6.1%, the proposed designs use enriched uranium in the Mo-99 producing fuel pins. The challenge lies in designing a fuel that is able to produce significant quantities of Mo-99 while having similar neutronics and thermalhydraulic characteristics to the standard CANDU fuel. The proposed designs, when irradiated in the peak power channel of a CANDU core, are shown to produce significant quantities of Mo-99 while maintaining the necessary reactivity and power rating limits. The total Mo-99 production activities are found to be approximately 2335, 2297, 2336, 4131 and 4268 six-day Curies per bundle for Designs 1 to 5, respectively. The yield corresponds to approximately 19% (for Designs 1, 2 and 3) and 34% (for Designs 4 and 5) of the world weekly demand for Mo-99. A production cycle of 6 bundles per week (for Designs 1, 2 and 3), or 3 bundles per week (for Designs 4 and 5) can meet the global demand of Mo-99 medical isotopes.