Analysis of Th-U and U-Pu fuel cycle in a 2500 MWth molten chloride salt fast reactor

[Background] The molten chloride salt fast reactor (MCFR) has advantages of high solubility of nuclear fuel and fast neutron spectrum, which makes it possible to achieve high breeding and transmutation efficiency. [Purpose] This study aims to investigate the neutronics characteristics of Th-U fuel cycle and U-Pu fuel cycle in a 2500 MWth MCFR, including the critical characteristic, burnup evolution, and breeding and transmutation performance. [Methods] The ²³³U and ²³⁹Pu were used as ignition fuels of Th-U fuel cycle (U3+Th) and U-Pu fuel cycle (Pu9+DU) respectively, and their fertile materials were ²³²Th and depleted uranium (DU), correspondingly. The analysis of the transition modes TRU+Th and TRU+DU with TRU as ignition fuel are also introduced. [Results] Considering the neutron absorption rate of actinides, neutrons produced per fission (ν) and the conversion ratio (CR), nuclear fuel cycle mode of U3+Th needs a variable feed of fissile fuel to maintain the critical operation of the core, whereas Pu9+DU, TRU+DU and TRU+Th can be operated for a long time without on-line refueling, that is 46 a, 50 a and 29 a, respectively. [Conclusions]TRU+Th fuel cycle mode is promising to MCFR due to its high self-sustaining breeding and high effective transmutation. (authors)