Application of arc-dpa model to estimate the primary radiation damage of structural materials by neutrons and the necessity of rescaling dpa versus final experimental damage correlations

Abstract

The primary radiation damage (PRD) in structural materials is generally assessed in terms of the displacements per atom (dpa). The athermal recombination corrected displacements per atom (arc-dpa) model, used to predict PRD in materials has been incorporated in the Kalpakkam code CRaD. A recent parameterization of the arc-dpa model for various materials by Konobeyev et al. is available. This parameterization has facilitated a comparison between the predictions of the PRD levels in structural materials from NRT and arc-dpa models by using the CRaD code. A reference database of neutron dpa cross sections has been created by CRaD based on these two models by using the data from ENDF/B-VII.1 nuclear data library. The erstwhile design manuals of nuclear systems would have a specified limit of dpa towards life time integrity corresponding to methods and nuclear data used at that time. The new design manuals will have the same engineering damage correlated to the revised value of the dpa corresponding to the use of improved models of dpa and updated nuclear data for the same irradiation conditions. Therefore, the rescaling of dpa versus engineering damage is necessary, as the dpa is presently calculated using improved basic evaluated nuclear data and models for atom-displacement damage. The design life of nuclear systems is determined by the irradiation conditions, but the rescaling of dpa in the correlations of dpa versus damage makes sure that the updated dpa obtained with new data and methods is used correctly in design studies.