Study of (U,Pu)O2-x mixed oxide properties using atomistic simulation: impact of irradiation.

Envoyé par JBouchet 
A fully funded PhD position on multi-scale modeling of mixed oxides is open at CEA CADARACHE (Aix en Provence), France. The PhD is expected to start autumn 2021 and lasts three years.


Nowadays, materials models and simulation tools are fully integrated in the experimental study of the behaviour of materials. The modelling has to be performed at the full size object (macroscopic scale) using models whose relevance is demonstrated by simulations performed at lower scales. In this multi-scale approach widely used at the CEA, atomic-scale simulations tend to occupy an increasingly large place due to their solid scientific bases and their broad field of application allowed by high performance computing. Until recently, these simulations were limited to the modelling of single crystal systems without defect. As real materials are most of the time polycrystalline and always contain defects and impurities, atomic scale simulations have to integrate these specificities.
During this thesis, we will try to apply this approach to mixed oxide (U,Pu)O2, currently used as fuels in generation 2 & 3 French nuclear reactors and best candidate for future generation IV fast neutron reactors (FNR). Currently, atomic scale simulation of this material is performed for a perfect crystal with a stoichiometry of two oxygen atoms to one metal atom (U or Pu). To relate to the real fuel material, which is by design hypostoichiometric for FNR, it is necessary to study systems including vacancies. Likewise, to move towards a better knowledge of the irradiated material, we now wish to include irradiation damages (point defects, dislocations, fission products, etc.) directly in our calculations at the atomic scale.
The student will use tools widely applied in material science (molecular dynamics, Monte Carlo, kinetic models, ...). He(She) will work in a scientific environment with extensive expertise on multiscale modelling of materials, and will have the opportunity to publish and to participate to international conferences in the field of materials, to exchange with foreign researchers and / or to share our experience with other areas of activity. In order to compare modelling to the most recent experimental results, this work will be performed in the frame of a close collaboration with the CEA experimenters in charge of fuel characterization.

The position is funded by a grant from CEA (net grant: ~1600 €/month).

The candidates must have a Master degree in quantum or solid-state physics and have strong computational skills. They shall send a CV, a letter of motivation, a transcript of academic results, and two contacts for references to:

Emeric BOURASSEAU (emeric.bourasseau@cea.fr)
CEA
DES/IRESNE/DEC/SESC/LM2C
Institut de recherche sur les systèmes nucléaires pour la production d’énergie bas carbone (IRESNE)

and/or

Johann BOUCHET (johann.bouchet@cea.fr)
CEA
DES/IRESNE/DEC/SESC/LM2C
Institut de recherche sur les systèmes nucléaires pour la production d’énergie bas carbone (IRESNE)