ARC-DPA model calibration for simil AIM1 austenitic steel

This study aims to achieve a more accurate assessment of radiation damage in a structural steel for Fast Reactors through model calibration. Molecular Dynamics (MD) simulations were performed to characterise primary radiation damage in a FeCrNi solid-solution modelling the AIM1 austenitic steel. The threshold displacement energy (TDE) was first evaluated for Fe, Cr, and Ni primary knock-on atoms (PKAs) along uniformly distributed directions, providing the basis for quantifying defect production under irradiation. Despite the compositional complexity, the three atomic species exhibit similar behavior, suggesting a limited influence of alloying. The evolution of defect production with increasing PKA energy reveals two distinct regimes: up to about 10 keV, damage is dominated by isolated Frenkel pairs, while at higher energies, extended clustering prevails. Within the first energy regime, the ARC (Athermal Recombination Corrected) model reproduces the MD results more accurately than the traditional NRT approach, highlighting the need to update damage models for a more realistic description of defect production in FeCrNi alloys.