Sujet de thèse: Multi-scale modeling of UO2 plasticity: on the role of irradiation defects.
Ph.D Advisors: Dr. Jonathan Amodeo, Pr. David Rodney.
Funding: CEA Cadarache (Dr. Bruno Michel, Dr. Emeric Bourasseau).
Uranium dioxide (UO2) is used in fuel pellets of nuclear power plants. Its mechanical behavior under irradiation has a major impact on fuel cladding structural integrity assessment under normal and off-normal operating conditions. One issue concerning the fuel mechanical behavior is a detailed understanding of deformation processes at the scale of the microstructure heterogeneity in order to be able to predict stress and strain inside the grains and at their interfaces.</p><p>The main goal of Marion's Ph.D is to develop a constitutive model based on dislocation interactions with irradiation loops. This model is needed to compute inelastic strains induced at high temperature and under irradiation. First, dislocation mobility and reactions between defects will be characterized using the atomic scale LAMMPS molecular dynamics (MD) package. Then, atomistically-informed dislocation dynamics (DD) simulations will be performed at the grain scale to quantify strain hardening induced by irradiation defects using the NUMODIS code.