General information
Organisation
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
Reference
2024-33352
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
Category
Materials, solid state physics
Contract
Internship
Job title
Molecular dynamics simulation of thermodiffusion in nuclear fuel materials
Subject
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)
6
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. For this reason, the lab is developing atomistic simulations in order predict this parameter.
Several methods of calculating Q* for the oxygen ion using classical molecular dynamics have proved relevant [1]. However, this technique is not a priori suitable for calculating Q* for electronic defects (polarons): quantum calculations are required in principle, but they are too computationally expensive. The aim of the internship is therefore to test classical molecular dynamics methods adapted to the approximate calculation of the electron/hole heat of transport. All necessary parameters will be determined using both quantum and classical calculations.
This topic will enable the candidate to develop general skills in solid state physics, quantum physics, equilibrium and non-equilibrium statistical physics and also in atomistic calculations using versatile DFT (e.g. ABINIT) and molecular dynamics codes (e.g. LAMMPS), in which the laboratory has considerable expertise. These skills can be applied to other physical situations and industrial fields (petroleum fluids, thermoelectric materials, etc.).
This project is linked to the development of the fuel simulation platform (PLEIADES), which brings together in a single environment the models corresponding to all the phenomena involved in material evolution (mechanics, physico-chemistry, thermodynamics, neutronics). In this context, the laboratory contributes to the calculation of material properties used as input parameters for the platform, based on a multiscale approach coordinating atomistic calculations up to larger scale simulations.
This work environment, where physicists, computer scientists and digital experts closely collaborate, is an excellent opportunity to discover a wide range of professions in numerical physics and computer science. Moreover, this internship is an opportunity to see for yourself how microscopic computational approaches ultimately help to solve complex practical problems.
Références :
[1] Bareigts et al. « Molecular dynamics modeling of thermodiffusion in solids with charged defects using uranium dioxide as the case study ». Chemical Engineering Science 281 (2023): 119141. doi.org/10.1016/j.ces.2023.119141.
[2] Konarski et al. Journal of Nuclear Materials 519:104, 2019
Methods / Means
Molecular Dynamics code LAMMPS, ab initio simulation tool ABINIT
Applicant Profile
Master's degree or equivalent in solid state physics, modelling or numerical physics, statistical physics, molecular dynamics
Position location
Site
Cadarache
Job location
France, Provence-Côte d'Azur, Bouches du Rhône (13)
Location
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
Oui
Requester
Position start date
03/01/2024