[SY-B2] Atomic scale calculations of nuclear fuel properties to sustain multiscale modeling of fuel behavior
Invited
Until recently, simulations of the fuel behavior during normal or accidental operation in nuclear reactor were based on rather empirical laws built from numerous experimental observations. Nowadays, simulation codes try to render the underlying physics, and are used to understand the measurements performed during irradiations or post-irradiation experiments. Thus, the fuel modelling and the laws used to predict its behavior must be improved by fundamental researches and feed by results from separate effects experiments. In support to these experiments, multi-scale modelling is an important tool, which aim is to understand the phenomena occurring at the microscopic scale to improve the modelling of the material at the macroscopic scale.
In this presentation, we will show our recent works concerning atomic scale simulations used to improve the knowledge of nuclear fuel properties before and during irradiation. Three points will be emphasized. First, we will present ab initio calculations of point defects in MOX fuels, and how they can be used to determine the elementary mechanisms of atomic diffusion in the irradiated fuel. Then, we will show a study of the energetic and structural properties of grain boundaries in UO2 using classical molecular dynamics. In particular, an interesting correlation observed between cleavage energy and disorientation angle will be shown. And finally, we will present the results of the determination of thermodynamic properties of (U,Pu)O2 through molecular Monte Carlo method. This method appears to be particularly relevant to explore the various cationic configurations available in mixed oxide.
For each examples, we will try to underline the link with experimental works, and to show how our results are included in simulations at higher scales.
In this presentation, we will show our recent works concerning atomic scale simulations used to improve the knowledge of nuclear fuel properties before and during irradiation. Three points will be emphasized. First, we will present ab initio calculations of point defects in MOX fuels, and how they can be used to determine the elementary mechanisms of atomic diffusion in the irradiated fuel. Then, we will show a study of the energetic and structural properties of grain boundaries in UO2 using classical molecular dynamics. In particular, an interesting correlation observed between cleavage energy and disorientation angle will be shown. And finally, we will present the results of the determination of thermodynamic properties of (U,Pu)O2 through molecular Monte Carlo method. This method appears to be particularly relevant to explore the various cationic configurations available in mixed oxide.
For each examples, we will try to underline the link with experimental works, and to show how our results are included in simulations at higher scales.