Bipolar plate design optimization
The large-scale deployment of fuel cells depends on increasing their performance and durability. Here we address these two aspects via the design of the bipolar plates in the fuel cell core.
The design of the membrane-electrode assembly (MEA) is a key and widely studied point for performance and durability. However, the design of the bipolar plates also plays a decisive role and, for the same MEA, can make all the difference. To achieve this, optimising the design of the bipolar plates' active zone and homogeneity zones enables the maximum amount of energy to be extracted for a given configuration, maximising performance while ensuring the homogeneity needed to avoid creating differential degradation, in other words, promoting durability.
Conception and deployment of innovative optimal control strategies for smart energy grids
District heating networks (DHNs) play a vital role in energy transition strategies due to their ability to integrate renewable and waste heat effectively. In France, the national low-carbon strategy emphasizes expanding and optimizing DHNs, including smaller networks with multiple heat sources like solar thermal and storage. Smart control systems, such as model-predictive control (MPC), aim to replace manual, expert-based practices to enhance efficiency. However, deploying advanced control systems on small DHNs remains challenging due to the cost and complexity of hardware and maintenance requirements.
Current industrial solutions for large DHNs leverage mixed-integer linear programming (MILP) for real-time optimization, while smaller networks often rely on rule-based systems. Research efforts focus on simplifying MPC models, utilizing offline pre-calculations, or incorporating machine learning to reduce complexity. Comparative studies assess various control strategies for adaptability, interpretability, and operational performance.
This postdoctoral project aims to advance DHN control strategies by developing, testing, and deploying innovative approaches on a real DHN experimental site. It involves creating and comparing control models, implementing them in a physical simulator, and deploying the most promising solutions. Objectives include optimizing operational costs, improving system robustness, and simplifying deployment while disseminating findings through conferences, publications, and potential patents. The researcher will have access to cutting-edge tools, computational resources, and experimental facilities.
Quasi-particle finite amplitude method applied to the charge exchange process in nuclear strength function models
Quasi-particle finite amplitude method (QFAM) has become the tool of choice to perform fast and accurate calculations of the nuclear strength function. Such a method is particularly interesting when applied to deformed nuclei, where traditional approaches based on large-scale matrix diagonalizations becomes almost intractable.
The goal of the current project is to extend the QFAM code developed at CEA to allow for charge exchange process and to calculate rates of ß- decay for all medium-mass and heavy even-even nuclei between the valley of stability and the neutron drip line using the newly fitted Gogny interactions.
By creating a shared databases of ß- decay rates with collaborators working in other CEA research units, we will perform systematic comparison with existing data in order to identify possible outliers and/or discrepancies.
Influence of concentrated electrolytes on the hydration of ternary binders with reduced carbon footprint
The evolution of the cement industry towards reducing its environmental footprint is expected to lead to the gradual disappearance of high-clinker binders, which are currently used for the conditioning of certain types of radioactive waste, such as evaporator concentrates. In contrast, novel cements (e.g., CEM II/C-M, CEM VI, LC3) are under development or standardization, offering new opportunities to design cement-based matrices with reduced environmental impact. However, their performance needs to be thoroughly evaluated to anticipate their industrial implementation for radioactive waste management.
This project will focus particularly on the influence of key ionic species present in evaporator concentrates on the hydration of ternary binders consisting of clinker, calcined clay, and limestone filler. Experiments will be conducted using non-radioactive surrogates. In addition to commercial cements, laboratory-prepared mixes will be used, allowing for more precise control over the content of clinker and supplementary cementitious materials. To understand the mechanisms involved in ion-induced acceleration or retardation of cement hydration, the hydration rate, phase evolution and microstructure will be investigated using a variety of techniques. The experimental results will then be used as input data for thermodynamic modelling of the hydration of these low-carbon binders by concentrated electrolytes.
This project is aimed at a postdoctoral researcher interested in developing expertise in materials chemistry and thermodynamic modeling, with a focus on advancing low-carbon cement chemistry and exploring new solutions for radioactive waste conditioning. It will be conducted within the framework of the EURAD2 European project at the Design and Characterization of Mineral Materials Laboratory (CEA/LFCM), with opportunities for collaboration with other European laboratories.
Improvement of the AmSel process for americium recovery within TRANSPARANT European project
Uranium and plutonium can already be industrially separated from spent nuclear fuels by the PUREX solvent extraction process. By recovering americium from a PUREX raffinate, the capacity of a deep geological repository can be increased by a factor of up to seven. This separation became feasible by ingeniously combining the selectivity of a suitable extracting agent (TODGA) and a water-soluble complexing agent (PrOH-BPTD). The former co-extracts americium, curium, and lanthanides into the organic phase, rejecting other fission products (FP). The development of this process, called AmSel, was already initiated during previous European projects but the selectivity could be further improved, especially the Cm/Am separation factor. In order to separate those elements, which have very close physico-chemical properties, both the lipophilic extractant molecule in the organic phase and the complexing agent in nitric acid medium should be optimized. Batch extraction tests will be performed in glove boxes in ATALANTE facility at CEA Marcoule with radionuclides of interest (241Am, 244Cm, 152Eu). The behavior of relevant fission products (e. g. Tc, Pd, Zr, Mo, Ru, Sr) both in extraction and stripping conditions will also be evaluated. Experiments using a simulated feed solution containing all elements (including americium) in nominal concentrations will validate the loading capacity and separation performances. The resistance towards radiolysis of the selective ligand used as Am stripping agent in the aqueous phase will be evaluated by in situ alpha irradiations with 241Am in nominal concentration. Degradation will be evaluated by ESI-MS measurements coupled with HPLC to both identify and eventually quantify degradation products and complexes formed with those compounds.
Understanding and modeling of corrosion mechanism for fuel-cladding interaction of 4th generation reactors type SFR
This study takes part in the Sodium-cooled Fast Reactor project. In this context, ferritic or austenitic steel claddings, containing UOX or MOX fuel are subject to corrosion by the elements from the fuel fission. Indeed, this corrosion is the limiting factor for the lifetime of claddings within the reactor and therefore a limiting factor for the reactor efficiency.
Sharp understanding of the corrosion mechanism of these claddings is necessary both to find ways to limit it and secondly to model the corrosion kinetics in order to estimate the lifetime of the pins as a function of reactor parameters (power, cladding temperature, burn up, temperature gradient...).
The objective of this study is then, firstly, to identify the corrosion mechanism from a thermodynamic approach using Thermocalc software as well as from corrosion experiments and from a corrosion kinetics obtention. Then, in a second step, the identified mechanism will be modelled. The corrosion kinetics modelling will permit to predict the material behaviour as a function of temperature and environmental chemistry.
Development of a 2D kinetic model for the high-temperature oxidation of chromia-forming alloys.
For many industrial applications, the high temperature oxidation phenomena of components need to be assessed in order to optimise the design of the component. This is the case, for example, for aircraft engine turbines in the aerospace industry (ambient temperatures of 1000°C), heat exchanger tubes in power plants (temperatures of 300 to 600°C), vitrification pots for long-lived radioactive waste (temperatures in excess of 1000°C), etc. All these applications use Fe-Ni-Cr alloys, the oxidation of which leads to the formation of a layer of chromium oxide, Cr2O3. The development of reliable models and simulation tools for the oxidation of Fe-Ni-Cr alloys at high temperatures (from 350°C) is therefore a major challenge for limiting the costs associated with high-temperature applications.
The post-doc will be divided into two parts: the first will involve using a simulation tool created at the CEA (EKINOX-FeNiCr) and the second will be based on the transition from the 1D model to the 2D model in order to take into account the finite size of components or geometric singularities.
The generality of this subject, which can be applied to many industrial cases, and the detailed understanding of oxidation phenomena will enable the student to move into both academic and industrial research at the end of the post-doctorate.
Post-doctoral position in Solid State Electrochemistry / Ceramic and metallic materials / High temperature corrosion
High-temperature electrochemical solid oxide (SOC) devices (650-850 °C) are considered as one of the most promising technologies thanks to various advantages such as a high efficiency, a relative low cost and a good reversibility in fuel cell (SOFC) and electrolysis (SOEC) operating modes. To better understand and limit metallic interconnect oxidation and chromium evaporation through the use of coatings remains a key challenge for the optimization of the system durability in SOFC and SOEC operation (degradation rate 3000 h). The post-doctoral work represents the main part of this project and is exclusively funded by it. The evaluation of protective coatings and a contact layer will be mainly performed thanks to electrochemical characterizations of performances and durability of the adjacent cell, and post-test microstructural characterizations as well compared to the bare steel. This work should lead to at least 1 publication and 1 presentation at EFCF conference in 2026.
Solid-electrolyte developpement
This post-doctorate position is a part of the ArgyL Carnot project which aims at developping better solid électrolytes for Li batteries. The main goal is to stabilize the Li/electrolyte interface in order to increase the lifetime of these systems that promise better Energy Density than the actual ones.
This project relies on the complementarity between the experimental approach based on the synthesis and on Advanced characterization and the computational simulations.
The post-doctorate will be based at the Materials laboratory where he will be in charge of synthesizing the new electrolyte compositions. He will also take part in the development of a new operando XPS analysis technique on our Nanocharaterization platform. This technique will allow him to probe in real time the interface between Li and electrolyte during cycling.
Finally, he will also interact with the LMPS simulation team who will use the data to feed their ab initio model.
Generative deep-learning modeling and machine-learning potentials for the calculation of atomic-scale transport properties in disordered uranium-plutonium mixed oxides
Machine learning (ML) is now commonly used in materials science to enhance the predictive capabilities of physical models. ML interatomic potentials (MLIP) trained on electronic-structure calculations have become standard tools for conducting efficient yet physically accurate molecular dynamics simulations. More recently, unsupervised generative ML models are being explored to learn hidden property distributions, and generate new atomic structures according to these distributions. This is useful for chemically disordered solid solutions, whose properties depend on the distribution of chemical species in the crystal lattice. In such cases, the number of possible configurations is so large that exhaustive sampling is beyond the capability of conventional methods. An example is U-Pu mixed oxides (MOX), a type of nuclear fuel that can significantly reduce the volume and radiotoxicity of spent-fuel waste. High-entropy alloys are another class of disordered materials that are promising candidates for radiation-resistant nuclear materials.
The goal is to combine MLIPs and generative methods to address atomic transport properties in MOX. The candidate will use in-house ML generative tools to generate representative atomic configurations and build an ab initio database. They will use this database to train a new MLIP for MOX, leveraging the experience gained from developing analogous MLIPs for the pure UO2 and PuO2 oxides. Finally, they will apply the MLIP to calculate atomic diffusion coefficients, crucial for predicting irradiation-induced microstructure evolution and in-reactor behavior.
The work will be conducted at the Nuclear Fuel Department (IRESNE, CEA Cadarache), within a scientific environment characterized by a high level of expertise in materials modelling, and in close collaboration with other CEA teams in the Paris region specialized in ML methods. Results will be disseminated through scientific publications and participation in international conferences