Development of depletion calculation method considering continuous reprocessing and fuel flowing for molten salt reactors analysis

To achieve accurate simulation of the neutronic behavior in liquid-fueled Molten Salt Reactors (MSRs), this paper investigates a flow burnup calculation method of fuel flow effects and continuous refueling processes. Based on a Monte Carlo program, a non-homogeneous burnup matrix reconstruction equation was established according to the flow zones and nuclear reaction rates of the MSR. The Chebyshev Rational Approximation Method (CRAM) was employed to achieve efficient solving of the flowing depletion process. Simultaneously, continuous refueling and continuous reprocessing modules with customizable rates are developed. Using this model to perform numerical simulations on a Single-Fluid Molten Salt Breeder Reactor (MSBR), the results indicate that fuel flow significantly alters the spatial distribution of key nuclides. Specifically, compared to traditional static approximations, the dynamic flow-refueling mode reveals that the equilibrium inventories of short-lived isotopes, such as 135 Xe and 99 Mo, are approximately 60 % and 200 % higher, respectively. The research conclusions confirm that the computational framework constructed in this paper can accurately capture the unique physical characteristics of liquid-fueled reactors, providing a reliable numerical tool for the nuclear analysis and operational optimization of Thorium-based Molten Salt Reactors.