Impacts of core parameters on the capability of Cf-252 production in an MSR

Californium-252 (Cf-252) is a powerful neutron source for various applications including neutron radiography, reactor startup, cancer therapy, etc. However, the demand for Cf-252 exceeds its supply at present, and therefore becomes one of the most important restrictions on its applications. Molten salt reactor (MSR) has unique ad-vantages of no fuel rod fabrication, online reprocessing and very deep burnup, which permits flexible core design, substantial target loading into the fuel salt and sufficient depletion time, and is therefore expected to provide an effective solution for Cf-252 production. In this study, four different targets (DU, Pu, Am and Cm) and various mole fractions of the Am target in an MSR are proposed to evaluate the Cf-252 conversion capability. The results indicate that an alluring quality factor of Cf-252 with its mass fraction of over 80% in Cf can be obtained for the selected targets. The highest inventory and conversion rate for Cf-252 with the Cm target can achieve about 700 g and 0.14%, respectively, during the first 10-year operation. The Cf-252 production can be further improved with the increased mole fraction of target but with a deteriorated conversion rate of Cf-252 due to the hardened neutron spectrum and the weakened neutron captures of most isotopes in the reaction chains of Cf-252 formation.