The microstructure of the materials of the internal structure of Pressurized Water Reactors (PWRs), which play a key role notably in maintaining the fuel assemblies, will evolve under irradiation. A better understanding of these evolutions could allow a better prediction of the behavior in operation of these materials in austenitic stainless steels (Fe-Cr-Ni) of the 300 series, in particular the 304 grade. Swelling is one of these potential evolutions and the question of its existence at high doses is of importance with the aim of extending the operating time of PWRs.
The objective of this work is to provide a better understanding of the mechanisms of swelling and microstructural evolutions through an analytical study of the effect of helium (influence of the rate of helium implanted up to high dose, temperature, and concomitant presence of hydrogen ...). Fine characterizations (grain scale and bottom), coupled with simulations in cluster dynamics, will be carried out on austenitic stainless steels irradiated with ions.
This study will be conducted mainly at the CEA, in the “Service de Recherche en Matériaux et procédés Avancés” (SRMA) and “ Section de Recherches de Métallurgie Physique ” (SRMP). It will benefit from the available ion irradiation devices (JANNuS), microstructural characterizations (notably Transmission Electron Microscopy and Atom Probe Tomography) and modeling (cluster dynamics simulation) tools. It will be supervised by M. Legros (CEMES) and T. Jourdan (SRMP) and driven par J. Malaplate and A. Renault-Laborne (SRMA). This broad subject will allow the candidate to acquire training on the behavior of materials under irradiation and also strong skills in the field of microstructural characterization of materials and simulation.
This subject is aimed at a student in materials science, with skills/appetite in the field of materials characterization and simulation. A Master 2 internship is proposed prior to this subject.