Adaptive point kernel dose assessment method for cutting simulation on irregular geometries in nuclear facility decommissioning

Nuclear decommissioning tasks involve a large number of cutting activities and many irregular objects are produced. The objective of the paper is to propose a flexible dose assessment method for the cutting of contaminated structures with irregular geometries and radiation source. The method is based on virtual reality technology and Point-Kernel method. The initial geometry is designed with the three-dimensional computer-aided design tools. To simulate a cutting operation on an arbitrary structure, the cutting geometry and the approximate models of the products are built automatically with virtual reality technology. Point kernels are generated within the approximate models, and dose rates are calculated with the Point-Kernel method. In order to improve the dose calculation efficiency while maintaining the accuracy, an adaptive point kernels generation technique that can deal with arbitrary geometries is developed, and the density and distribution of point kernels are adapted to the position of the detecting point. To account for radiation scattering effects, buildup factors are calculated with the Geometric-Progression formula in the fitting function. The effectiveness and superiority of the proposed method were verified by simulating different geometries, and comparing the dose rate results with those derived from VRBM, CIDEC, and MCNP codes.