Radiation Shielding Analysis for Spent Fuel Salt in Maritime Environments

This study addresses the challenges of radiation shielding for transportation and interim storage of spent nuclear fuel (SNF) salt from molten salt reactors (MSR) in maritime environments. Traditional land-based shielding approaches prove inadequate for maritime settings, where spatial and weight constraints are more stringent. This paper proposes utilizing the flexibility of molten salt to create adaptive shielding configurations compatible with standard cargo containers, streamlining transportation logistics. Advanced Monte Carlo-based simulations are used to analyze a proposed SNF cask concept, focusing on typical shipyard steel (AH32) as the primary shielding material due to its compatibility with maritime infrastructure and adequate attenuation properties. Furthermore, the study applies an approach leveraging an efficiency curve based on global variance reduction to model photon transport. This method enables efficient exploration of a vast parameter space, specifically in cases where only the source spectrum changes, allowing for rapid assessment without the need for further particle transport simulations. Results indicate that the proposed container design meets criticality and radiation safety standards. This work marks a preliminary step toward a comprehensive solution for MSR SNF transport, with future studies planned to further optimize shielding design.