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Molecular dynamics simulation of thermodiffusion in nuclear fuel materials

Vacancy details

General information


The French Alternative Energies and Atomic Energy Commission (CEA) is a key player in research, development and innovation in four main areas :
• defence and security,
• nuclear energy (fission and fusion),
• technological research for industry,
• fundamental research in the physical sciences and life sciences.

Drawing on its widely acknowledged expertise, and thanks to its 16000 technicians, engineers, researchers and staff, the CEA actively participates in collaborative projects with a large number of academic and industrial partners.

The CEA is established in ten centers spread throughout France



Description de l'unité

The Unit of Study and Simulation of the Fuel Behaviour (SESC) is a team of about 70 engineers and researchers as well as ~30 PhD students that hosts each year about 20 trainees: Students from Master and License (Bachelor) of science as well as Engineer schools. This Unit belongs to the Fuel Study Department (DEC) and the IRESNE Institute (Research Institute for Nuclear Systems for Low Carbon Energy Production), a part of the Division of Energies of the French Atomic and Alternative Energy Commission (CEA). The CEA is committed to carrying out the R&D necessary for the implementation of a low-carbon energy mix in France, and as such is positioned at the top of the world rankings for the filing of patents concerning technological innovation for low-carbon energyThe SESC is located at the CEA Cadarache site, the major European research centre devoted to low-carbon energy: nuclear fission and fusion, solar energy and biofuels. The CEA Cadarache is located in the south of France about 40 kilometres from Aix-en-Provence.

Position description


Materials, solid state physics



Job title

Molecular dynamics simulation of thermodiffusion in nuclear fuel materials


Materials science is increasingly relying on multiscale simulation to address the complex in-reactor behaviour of nuclear materials, be it at the scale of the component (continuum mechanics,...), of the grain (phase field, rate theory...) or of the atoms (atomistic simulations). Thermodiffusion in nuclear fuel (UO2) is a phenomenon whose complexity requires such an approach [1].

Contract duration (months)


Job description

During irradiation, the fuel may experience a high thermal gradient that triggers the oxygen atoms migration (thermodiffusion). This phenomenon, inducing changes in the chemical characteristics of the material, is poorly understood at the microscopic level. Its key property, the heat of transport Q*, is an input parameter for the thermodiffusion model of the PLEIADES platform [2]. Unfortunately, it is very difficult to measure and, moreover, strongly affected by the physicochemical in-reactor evolution of the material.

Many atomistic simulations of thermodiffusion have been performed at the laboratory. Several methods for Q* evaluation have been tested; they provide very different results. The internship is aimed at understanding the cause of these discrepancies: simulations on simpler materials and situations will be carried out in the view of a better understanding of the mechanisms and of an improvement of the methods for Q* calculation.

The candidate will have the opportunity to develop skills in Statistical Physics, at and out of equilibrium, as well as in atomistic calculations with standard polyvalent molecular dynamics codes (i.e. LAMMPS) in which the laboratory is expert. Furthermore, these skills can be applied to a large spectrum of materials in various industrial fields such as electrolytic or thermoelectric materials (electronic industry) or liquid mixtures (petrol industry).

This project is connected to the development of the fuel simulation platform (PLEIADES) gathering in a single environment the models corresponding to all the phenomena involved in the material evolution (mechanics, physicochemistry, thermodynamics, neutronics). In this context, the laboratory contributes to the computation of material properties used as input parameters for the platform, based on a multiscale approach coordinating atomistic calculations up to larger scale simulations. This working environment comprising physicists, computer scientists and digital experts all together is a key opportunity to discover a large panel of professions in numerical physics and computer science. This internship offers the opportunity to discover by oneself the way microscopic computational approaches finally helps solving complex practical issues.

Références :
[1] Schelling et al., Journal of Applied Physics, 112:8, 2012.
[2] Konarski et al. Journal of Nuclear Materials 519:104, 2019

Methods / Means

Molecular Dynamics code LAMMPS

Applicant Profile

Master's degree or equivalent in solid state physics, modelling or numerical physics, statistical physics, molecular dynamics

Position location



Job location

France, Provence-Côte d'Azur, Bouches du Rhône (13)


Saint Paul lez Durance

Candidate criteria

Prepared diploma

Bac+5 - Master 2

Recommended training

Master's degree or equivalent in solid state physics, modelling or numerical physics

PhD opportunity



Position start date