Unified theoretical analysis of experimental swelling data for irradiated austenitic and ferritic/martensitic alloys

Abstract

Central concepts in the theory of swelling based on defect reactions are reviewed. The critical radius and critical number of gas atoms, which determine the initiation of swelling, and the ratio of the dislocation and cavity sink strengths, which dictates the swelling rate, are demonstrated to be of great utility in the understanding and control of swelling. Over the past two decades, a large data base has been accumulated covering austenitic and ferritic/martensitic alloys, the leading candidate materials for both fusion and fast fission reactor applications. This collection of data naturally serves as the largest source of information on which to develop and test mechanistic understanding of swelling. Over wide ranges in materials and irradiation parameters, including composition, temperature, damage rate, and helium generation rate, we find that apparently divergent swelling behaviors can be explained in a unified manner within the present theoretical framework. Principles for microstructures that insure swelling resistance, together with results from the necessary confirmatory experiments, are described.