An automated weight window generator based on the recursive Monte-Carlo method for use in MC shielding calculations

Abstract

MCNP code provides numerous variance reduction techniques that are mainly used to optimize the analog Monte Carlo simulations. These techniques can reduce the statistical uncertainty of the simulation results while minimizing computational costs. Weight window is one such technique that is commonly used to optimize shielding calculations. However, for complex shielding problems such as deep penetration, the existing MCNP weight window generator is not efficient enough to generate the appropriate weight parameters for the weight window in a single run. To address this issue, an automated algorithm was developed using the code TRAWEI, which is based on recursive Monte Carlo methodology. The TRAWEI code can generate suitable weight values in a single run with less calculation time. This paper focuses on the verification of TRAWEI-generated weights using a simplified cask model. Further, the results of MCNP simulation using TRAWEI-generated weights are compared with those using weights generated by an existing MCNP weight window generator.