Weight Windows Variance Reduction in Monte Carlo Particle Transport and Its Application in ITER Shielding Analysis

Radiation shielding is one of the most important points in the research of fusion neutronics.Weight windows variance reduction in Monte Carlo particle transport is an important method to deal with deep penetration problem in shielding calculation.Weight windows variance reduction was studied and implemented in Super Monte Carlo Calculation Program for Nuclear and Radiation Process(SuperMC).The concrete benchmark case and the fusion device shielding analysis case of ITER were selected as benchmark and application cases.Compared with calculated results of MCNP,the deviation of SuperMC met the requirement of deviation limit.With weight windows,the FOM(Figure of Merit)of SuperMC increased obviously.The results indicated the accuracy and feasibility of the method and the code.