Modelling and analysis of prospective scenarios for the deployment of hydrogen infrastructure in France and Germany
The use of hydrogen produced by electrolysis or of molecules derived from electrolytic hydrogen (synthetic methanol, synthetic kerosene, etc.) is one of the solutions envisioned to decarbonise certain sectors such as the steel industry and long-distance sea and air transport.
The development of a Europe-wide hydrogen transport infrastructure is considered to facilitate the development of electrolytic hydrogen production on the continent. This infrastructure could provide access to massive underground hydrogen storages unevenly distributed across Europe, facilitate exchanges between regions with high solar or wind energy potential and major industrial hubs and, in certain areas, limit the cost of reinforcing the electricity transmission network.
The goal of the CrossHy project is to analyse the possible deployment pathways for hydrogen transport infrastructure in France and Germany. Two complementary modelling tools (REMix, ANTARES) are going to be used and to develop a European-scale model and a regional-scale model of a cross-border-region.
Regular physical meetings between the French and German research teams are planned during the project; the post-doc will include a 3-month visit to Stuttgart to work and exchange with the DLR team involved in the project.
Decomposition of Fission Fragment Energy from Microscopic Approaches to Provide Input Data for the FIFRELIN Code
The FIFRELIN code (FIssion FRagment Evaporation modeLINg), developed since 2009 at the CEA, simulates the formation and decay of nuclear fission fragments. It contributes to the enrichment of the European nuclear data library JEFF, which is used for reactor simulations. The calculation proceeds in two steps: the generation of fission fragments (with their physical properties), followed by their decay using a Monte Carlo Hauser-Feshbach approach. At the moment of scission into two fragments, the total energy is split between kinetic energy (TKE) and excitation energy (TXE). The TXE is further divided into deformation energy and intrinsic excitation energy, which govern the emission of neutrons and photons. Accurate knowledge of both TXE and TKE is essential to improve FIFRELIN’s performance. Microscopic theoretical approaches (such as Hartree-Fock-Bogoliubov and the Generator Coordinate Method) are used and developed within DES to provide theoretical input supporting evaluated nuclear data. This postdoctoral position aims to use and enhance these models to gain a more detailed understanding of nuclear properties at scission. The desired candidate has several years of experience (3 years or more) in nuclear mean-field theory (such as Hartree-Fock-Bogoliubov, relativistic mean-field, etc.) or in the generator coordinate method.
Study of the Velocity-Vorticity-Pression formulation for discretising the Navier-Stokes equations.
The incompressible Navier-Stokes equations are among the most widely used models to describe the flow of a Newtonian fluid (i.e. a fluid whose viscosity is independent of the external forces applied to the fluid). These equations model the fluid's velocity field and pressure field. The first of the two equations is none other than Newton's law, while the second derives from the conservation of mass in the case of an incompressible fluid (the divergence of velocity vanishes). The numerical approximation of these equations is a real challenge because of their three-dimensional and unsteady nature, the vanishing divergence constraint and the non-linearity of the convection term. Various discretisation methods exist, but for most of them, the mass conservation equation is not satisfied exactly. An alternative is to introduce the vorticity of the fluid as an additional unknown, equal to the curl of the velocity. The Navier-Stokes equations are then rewritten with three equations. The post-doc involves studying this formulation from a theoretical and numerical point of view and proposing an efficient algorithm for solving it, in the TrioCFD code.
VALERIAN: caracterizing electron transport for the ITkPix modules of ATLAS
A precise description of the transport of electrons and photons in matter is crucial in several of the CEA's flagship fields, notably radiation protection and nuclear
instrumentation. Their validation requires dedicated parametric studies and measurements.Given the scarcity of public experimental data, comparisons between calculation codes are also used. The challenge for the coming years is to qualify these codes in a broad energy domain, as certain discrepancies between their results have been identified during preliminary SERMA studies involving the coupled transport of neutrons, photons and electrons. The VALERIAN project involves seizing the opportunity created by a unique data collection Campaign planned for 2025-2026 at the IRFU (DRF) to better characterise these discrepancies. The IRFU has undertaken to check at least 750 pixel modules for the new trajectograph of the ATLAS experiment, as part of the rejuvenation of the large detectors at CERN. Numerous measurements with beta sources will be carried out in 2025-2026 for the qualification of these modules.
Study of the Thermodiffusion of Small Polarons in UO2
The position is published on the CEA website at the following address:
https://www.emploi.cea.fr/job/emploi-post-doctorat-etude-en-ab-initio-de-la-thermodiffusion-des-petits-polarons-dans-UO2-h-f_36670.aspx
Modelling of prospective deployment scenarios for hydrogen in France and Europe M/F
One of the major energy transition leverages at the horizon 2050 is decarbonation of uses such as electricity production, transport or industry. If electrification of some uses is part of the solution, a potential is also foreseen in using decarbonized intermediate vectors such as hydrogen, produced by electrolysis, and which can be leveraged both as an energy vector and as a substitute molecule in carbon-emitting industries like chemistry, steel production, etc.
However, the potential high development of hydrogen creates underlying needs for electricity production, leading to questions about the sustainability aspects of such deployments, a possible criteria when choosing between different possible deployment options.
As part of a “PEPR Hydrogène” research project, the study aims at 1/ developing possible quantitative hydrogen deployment scenarios consistent between different geographic scales (from the French regions to the national and European level), in collaboration with project partners, 2/ assessing the consequences of these scenarios on the European electrical production system and consequently on the characteristics of the electricity used for the hydrogen production – in particular from the sustainability point of view (e.g. electricity cost and greenhouse gas emissions).
Impact of Microstructure in Uranium Dioxide on Ballistic and Electronic Damage
During reactor irradiation, nuclear fuel pellets undergo microstructural changes. Beyond 40 GWd/tU, a High Burnup Structure (HBS) appears at the pellet periphery, where initial grains (~10 µm) fragment into sub-grains (~0.2 µm). In the pellet center, under high temperatures, weakly misoriented sub-grains also form. These changes result from energy loss by fission products, leading to defects such as dislocations and cavities. To study grain size effects on irradiation damage, nanostructured UO2 samples will be synthesized at JRC-K, using flash sintering for high-density pellets. Ion irradiation experiments will follow at JANNuS-Saclay and GSI, with structural characterizations via Raman spectroscopy, TEM, SEM-EBSD, and XRD. The postdoc project will take place at JRC-K, CEA Saclay, and CEA Cadarache under expert supervision.
Thermochemical and thermodynamic study of chloride molten salts
In today’s climate emergency, access to clean and cheap energy is more important than ever. Several ways have been envisaged for several years now, but a number of technological issues still need to be overcome before they can be put into practice, as they represent breakthroughts. Whether for energy storage than for fourth generation nuclear reactors, molten salt environment used as coolant and/or as fuel is highly corrosive requiring a complexe choice of structural materials.
The aim of this subject proposed in the Corrosion and Materials Behavior Section is to study in depth the chemical properties of different chloride molten salts : the basic ternary salt (NaCl-MgCl2-CeCl3) but also the corrosion/fission/activation products that can be produced (MxCly with M=Cr, Fe, Te, Nd, Ni, Mo,…). The activity coefficients and solubility limits of these metallic elements will be determined using various techniques such as electrochemistry and Knudsen cell mass spectrometry. If required, this study can be completed by the phase transition temperature and heat capacity measurements using differential scanning calorimetry.
Optimizing phytotechnologies for the remediation of contaminated nuclear sites
CEA is recruiting a postdoctoral researcher for a research project aimed at optimizing phytotechnologies for the remediation of contaminated nuclear sites. This research is part of the risk management and remediation of contaminated soils, in particular those resulting from the decommissioning of nuclear facilities. The aim of the project is to develop an advanced mechanistic model of soil-plant transfers, in order to gain a better understanding of contaminant mobility in lightly contaminated soils, and to optimize the use of suitable plants to stabilize these contaminants.
Development of new Potassium-ion cells with high performances and low environmental impact
Lithium ion batteries are considered as the reference system in terms of energy density and cycle life and will play a key role in the energetic transition, especially concerning electric vehicles. However, such a technology involves the use of a large amount of critical elements and active materials are synthesised using energy intensive processes.
In this way, our team is developing a new Potassium-ion batteries technology with high performances but with a low environmental impact.
For this innovative and ambitious project, CEA-LITEN (one of the most important research institute in Europe) is looking for a talented post-doctoral researcher in material chemistry. The post-doctoral position is opened for a young researcher with a high scientific level, interested by valorising her/his results through different patents and/or scientific publications.