Abstract: [Background] ThorCon reactor is a thermal reactor using molten salt (NaF-BeF₂-ThF₄-UF₄) as fuel and coolant and graphite as moderator. Tritium would be produced by nuclear reaction of Be, F in NaF-BeF₂-ThF₄-UF₄ and B graphite, which has strong penetration ability at high temperature, affecting the mechanical properties of the structure and reduce its life. And the tritium is easily changed into trialed water, which may enter the human body, causing internal radiation. [Purpose] This paper aims to predict the production of tritium and its main reaction. [Methods] The tritium production reaction was divided into three types based on the number of intermediate products in the reaction channel, such as producing tritium by nuclear reactions with or without intermediate products and by ternary fission. Three corresponding equations were set up accordingly. [Results] The results showed that the annual tritium production was about 5.444 g, and 88.5% of tritium came from Be. [Conclusion] If the amount of Be can be reduced, the yield of tritium will be greatly reduced.

Key words: ThorCon reactor, Tritium production, NaF-BeF₂-ThF₄-UF₄