Development of a BIM-based radiation modeling method and its applicability for nuclear facility decommissioning support

Abstract

A BIM-based radiation modeling method has been developed to estimate radiation source strengths from field-measured dose rates. Using an inverse source strength calculation via the point kernel approach, this method integrates geometric and material information extracted from the BIM model. The developed method has been incorporated into a program tool called BIMRAD, and was validated through various sample cases. The estimation accuracy of this method is considered acceptable, aligning with industry conventions regarding uncertainty tolerance. BIMRAD can generate dose rate distributions and assess radiation work exposures throughout different stages of the dismantling process. Additionally, it provides 3D visualizations to enhance the understanding of radiation fields. This tracking simulation eliminates the need for additional dose rate measurements at each dismantling stage, once the source strengths are determined from initial stage measurements. Furthermore, BIMRAD can be utilized to evaluate alternative approaches for component dismantling and work planning during NPP decommissioning, supporting ALARA analyses by enabling users to retain or remove sources and shielding objects as needed.