Irradiation effects: modelling and experiments

Work-package WP3 aims at better understanding the microstructural evolution of austenitic stainless steels under irradiation. Such alloys will be used in GenIV prototypes (e.g. ASTRID) for both structures (316 L(N) steels) and cladding (AIM1-type steels). While the structure materials will receive a low irradiation flux and dose during a long time, the core components and the fuel cladding tubes will receive very high irradiation fluences, that in the temperature range of interest (300–700°C) produce new microstructure features, such as new families of precipitates, solute segregations at structural defects, point defect clusters and voids, leading to dimensional changes of the components (swelling). In addition, cladding materials are exposed to higher operating temperatures than structure materials, which brings about an aggravation of corrosion issues in the short term, and a concomitant need for protective coatings. Swelling, corrosion and mechanical issues limiting the lifetime of these materials are strongly related to their microstructure. It is then of prime importance to be able to predict their microstructure evolution.