CAD modeling study on FLUKA and OpenMC for accelerator driven system simulation

Accelerator driven system (ADS) is an advanced nuclear system with high inherent safety feature, which can transmute the nuclear waste including minor actinides (MA) and long-lived fission products (LLFPs) into short-lived fission products. In order to accomplish the neutronic simulation in ADS, a conventional way can be divided into two steps, namely the physical process of proton beam bombarding spallation target (FLUKA) and the neutron transport process in subcritical reactor coupling with a spallation neutron source (OpenMC). However, there are some difficulties in the modeling process for ADS, such as the inconsistent modeling process between FLUKA and OpenMC codes, and the error-prone process of constructing complex geometries. Therefore, it is imperative to build a code system that can convert the CAD modeling files into the input cards of Monte Carlo codes. In this context, a code system named CAD-PSFO (FreeCAD based parsing script for FLUKA and OpenMC) has been developed to solve the modeling conversion problem in ADS, in which basic geometry and boolean logic classes have been established with a mapping relationship to FLUKA and OpenMC codes, and ray-casting technology based iteration method has been proposed to solve the problem of higher-order surfaces in complex geometries. Finally, CAD-PSFO has been verified and validated by comparing with a reference model, two benchmarks, and two simulation tests.