Research and Validation of the Monte Carlo-based Multi-cycle Neutronic Calculation Methodology for High Flux Research Reactor

This paper focuses on the irradiation test in the high-flux research reactor. Based on the Monte Carlo neutron-photon transport-burnup coupling code, the physical processes of the generation, transport, leakage, and deposition of different particles in the global core environment and the local test device environment are studied, and a high-fidelity calculation model of energy deposition that can describe the physical processes of multi loops throughout the core is established based on the repetitive geometric structure. Taking into account the dynamic changes of fuel burnup, control rod position, and their coupling relationship with the particle transport process during the operation of the high-flux research reactor, the whole reactor refueling and fuel management calculations are realized, including multi-type of fuels and burnable poisons. Validation is performed using actual critical rod position, irradiation test assembly power, and point burnup measurement values under different burnup steps. The calculation results show that the error in the core neutron effective multiplication factor (k_eff) is less than 1200 pcm, and the average relative errors between calculated and measured values for irradiation test assembly power and point burnup are both less than 10%, verifying the accuracy of the multi-cycle calculation method.