Research on Preventing Xenon Oscillation in Monte Carlo Burnup Calculation Based on RMC

Monte Carlo burnup calculation suffers from numerical xenon oscillation when its model is huge geometry,refers as weakly coupled neutron transport system.Numerical xenon oscillation brings in error,even aborts burnup calculation.How to effectively prevent such oscillation is a significant topic in Monte Carlo burnup calculation.Forced equilibrium xenon method is effective when the power density used in each burnup step of the calculation keeps constant.This method has been researched and used in RMC,furthermore,some improvement has been complemented to extend range of burnup steps.Some popular international benchmarks,such as BEAVRS,VERA,require simulating burnup problem with variable power history.However,forced equilibrium xenon method inevitably brings error when power density changes by relative small burnup step.To research and develop advanced Monte Carlo simulating ability including high performance of burnup calculation,general equilibrium xenon method based on forced equilibrium method is researched and integrated to RMC.Numerical calculation result verifies that the general equilibrium xenon method is capable of effectively preventing xenon oscillation in Monte Carlo burnup calculation with constant or variable power density in each step.