OpenMC-Fusion-Benchmarks, a CAD-Based Automated Framework for Fusion Neutronics Validation

Currently, verification and validation (V&V) for fusion neutronics are largely performed manually: analysts convert benchmark models between code input formats and reformat the results for comparison, making the process time consuming, error prone, and hard to reproduce. Existing benchmark suites also rely almost exclusively on constructive solid geometry, thereby excluding from validation much of the practical neutronics workflow, including computer-aided design-based geometries, meshing, and transport on unstructured meshes. We propose a new approach to address these gaps, implemented in the open-source OpenMC-Fusion-Benchmarks (OFB) repository. The OFB provides a code-agnostic, standardized, and human-readable benchmark specification, with geometries supplied as Standard for the Exchange of Product (STEP) model data files and an automated meshing pipeline. The framework is designed to enable the near-fully automated V&V of neutronics codes and methods, from benchmark definition to simulation execution and results comparison. We illustrate the workflow on a representative benchmark and outline the remaining challenges and the future developments aimed at further automating and strengthening the validation of fusion neutronics tools.