Numerical study of tritium transport characteristics in Thorium Molten Salt Reactor with Solid Fuel (TMSR-SF)

Tritium control is one of the most key issues for the development of Molten Salt Reactor (MSR). The tritium transport characteristics in 2MWth Thorium Molten Salt Reactor-Solid Fuel (TMSR-SF) proposed by Shanghai INstitute of Applied Physics (SINAP) is studied in this paper. Three works are conducted: Firstly, an integrated numerical model is established, including tritium production, adsorption, diffusion, corrosion and permeation. Secondly, the Tritium trAnsPort chAracteristics analysiS code (TAPAS) for TMSR-SF is developed and benchmarked. The results prove the fidelity and accuracy of TAPAS. Finally, the distributions of the key variables including TF, T-2 and Cr2+ in TMSR-SF system at both steady and transient state are obtained. In addition, some methods for tritium mitigation are evaluated by TAPAS. Numerical results show that tritium can be efficiently removed from the molten salt via graphite absorption. The amount of T-2 at steady state is two orders of magnitude more than TF. Tritium permeation can be prevented by increasing Li-7 enrichment and reducing redox potential. Tungsten or similar low-permeability material is a candidate for tritium barrier when covered on the surface of the heat exchanger wall. This work provides some valuable considerations for the tritium control in the MSR.