Benchmarking point-kernel method against Monte Carlo simulations for an ALARA case study in occupational radiation protection

The principle of as low as reasonably achievable (ALARA) is of paramount importance for the radiation protection of workers, and more specifically in the context of the decommissioning of nuclear facilities. For that purpose, several tools have been developed to measure and assess radiation doses to workers, to plan radiological work, and to ensure that safety protocols are followed. Most of these planning tools are based on the well-established point-kernel (PK) method, while others rely on Monte Carlo (MC) simulations. The scope of this paper is to compare, for some case studies, the performance and accuracy of VISIPLAN 4.0, a PK-based tool developed at SCK CEN, with MC simulations, to highlight the advantages and limitations of both methods. The major advantage of PK methods is usually related to their lower computational burden, at the cost of a less accurate assessment of dose values. However, depending on the number of source points chosen for the PK method, the simulation time could be comparable to MC simulations: in the scenarios presented in this paper, the simulation time was comparable to MC simulations when a high number of source points was considered. Moreover, VISIPLAN, on average, overestimated the dose assessment by approximately 50% compared to MC results.