The LANIE laboratory is focused on downscaling the sample purification steps performed by solid-phase extraction chromatography. The strategy is based on the implantation of functionalized polymeric monoliths within the channels of microsystems made of cyclic olefin copolymer (COC), material known to be easy to process but chemically inert. Once this key step is validated, this project aims to set up a comprehensive analytical pipeline in the laboratory, starting from the design, prototyping, and manufacturing of integrated miniaturized extraction devices, up to their de facto implementation for the reduced-scale analysis of U- and Pu- based samples.
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.
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.
Fiber-reinforced ceramic matrix composites (CMCs) are a class of materials that combine good specific mechanical properties (properties relative to their density) with resistance to high temperatures (> 1000 °C), even in oxidizing atmospheres. They are typically composed of a carbon or ceramic fiber reinforcement and a ceramic matrix (carbide or oxide.
The proposed study focuses on the development of a low-matrix oxide/oxide CMC with suitable dielectric, thermal, and mechanical properties.
This study will be conducted in collaboration with several laboratories at CEA Le Ripault.
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.
As part of the Taranis project initiated by Thales and supported by BPI France and in collaboration with numerous scientific partners such as CEA/DAM, CELIA and LULI, work on target design and definition of the laser intended to energy production in direct drive will take place. A prerequisite for this work is to understand the laser-plasma interaction mechanisms that will occur when the laser is coupled with the target. These deleterious mechanisms for the success of fusion experiments can be regulated by the use of so-called “broadband” lasers. In addition, the choice of the laser wavelength used for the target design and the laser architecture must be defined. The objective of the postdoctoral position is to study the growth and evolution of these instabilities (Brillouin, Raman) in the presence of “broadband” lasers both from an experimental and simulation point of view, and thus to be able to define the laser conditions making it possible to reduce these parametric instabilities.
The miniaturisation of analytical steps commonly carried out in laboratories offers many advantages and particularly in the nuclear sector, where the reduction of material consumption and waste production is of major interest. In this context, one of our laboratory’s focus area is the miniaturisation of analytical tools, particularly chromatographic separation techniques. The aim of this project is to reduce the scale of the purification steps of nuclear samples by solid phase extraction chromatography, prior to the analytical processes. Obtaining these miniaturised extraction devices is based on the in situ synthesis and anchoring of monoliths, in the channels of cyclic olefin copolymer (COC) microsystems. Since this material is chemically inert, COC functionalisation strategies are currently under development to covalently graft reactive sites on its surface, before locally anchoring actinide-specific monoliths in the micro-channels. The aim is to design and fabricate chromatographic extraction microsystems in COC, and to implement them for chemical purification and mass spectrometry measurements, both off-line and on-line.
The ELIPSE process developed at the CEA allows the destruction of organic liquids by injection into a high-power plasma.
If the feasibility of destroying different organic components at flow rates of a few liters per hour has now been demonstrated, tests must now be further developed for reference organic liquids appropriately chosen according to existing deposits.
These studies, based on the characterization data of the chosen LORs, will aim to provide detailed process results obtained with the most representative operating conditions, to allow a complete and quantitative evaluation of the process. This will make it possible to establish operating, robustness and endurance data for the process.
This work will include the study of the behavior of radioelements in the process, which will be essential for the nuclearization study: this will involve studying the physico-chemical behavior of actinides during their processing via the use of inactive simulants.