Program system for three-dimensional coupled Monte Carlo-deterministic shielding analysis with application to the accelerator-based IFMIF neutron source

A program system for three-dimensional coupled Monte Carlo-deterministic shielding analysis has been developed to solve problems with complex geometry and bulk shield by integrating the Monte Carlo transport code MCNP, the three-dimensional discrete ordinates code TORT and a coupling interface program. A newly-proposed mapping approach is implemented in the interface program to calculate the angular flux distribution from the scored Monte Carlo particle tracks and generate the boundary source file for the use of TORT. Test calculations were performed with comparison to MCNP solutions. Satisfactory agreements were obtained between the results calculated by these two approaches. The program system has been chosen to treat the complicated shielding problem of the accelerator-based IFMIF neutron source. The successful application demonstrates that coupling scheme with the program system is a useful computational tool for the shielding analysis of complex and large nuclear facilities.