TOMOGLASS: Gamma Emission Tomography Applied to the Radiological Characterization of Glass Residues from the Cold Crucible Vitrification Process
The TOMOGLASS project aims to develop an innovative gamma tomography system capable of operating in high-activity environments to characterize in three dimensions the glass residues resulting from the vitrification process of nuclear waste. The objective is to precisely locate platinum-group inclusions, which are poorly soluble in glass, in order to improve the understanding and control of the process. The system is based on a compact gamma imager integrating high-resolution pixelated CZT detectors, pinhole-type collimation, and mounting on a robotic arm. It will enable multi-isotopic reconstruction using advanced tomographic algorithms. This project is part of the modernization of the La Hague facilities and the integration of digital technologies within the framework of the factory of the future.
The first phase of the project will consist in demonstrating the feasibility of implementing a spectro-imager prototype in a constrained environment, building on existing technological components: detection modules and acquisition electronics based on the HiSPECT technology, and image reconstruction algorithms developed at CEA-Leti. The work will focus on conducting a multi-parameter study through numerical simulations (Monte Carlo calculation code) to design an optimized measurement system, and to generate simulated datasets for various representative measurement configurations. Once the concept has been validated, the work will continue in year N+1 with the assembly of the prototype components and their integration on a robotic arm. Experimental tests may then be carried out to demonstrate the system in a representative environment.
Tools and diagnostic methods for the reuse of electronic components
The Autonomy and Sensor Integration Laboratory (LAIC) at CEA-Leti has the primary mission of developing sensor systems for the digitalization of systems. The team's activities are at the interface of hardware (electronics, optronics, semiconductors), software (artificial intelligence, signal processing), and systems (electronic architecture, mechatronics, multiphysics modeling).
In a context of exponential growth in electronics and scarcity of resources, the reuse of electronic components from end-of-life systems represents a promising avenue to limit environmental impact and support the development of a circular economy. The objective of this project is to develop an advanced diagnostic methodology to assess the health status of electronic components, particularly power components, to reintegrate them into a less constraining second-life cycle.
The postdoctoral researcher will be tasked with developing a comprehensive approach to evaluate the reuse potential of electronic components, with the aim of reintroducing them into second-life cycles. This will include:
- Identifying relevant health indicators to monitor the performance evolution of components (e.g., MOSFETs, IGBTs, capacitors, etc.);
- Setting up test benches and sensors adapted to measure electrical, thermal, or mechanical parameters, with the goal of detecting signs of aging;
- Analyzing degradation modes through experimental tests and failure models;
- Developing algorithms for predicting the remaining useful life (RUL) adapted to different usage scenarios;
- Contributing to scientific publications, the valorization of results, and collaboration with project partners.
Analysis of Gas Effluents for More Eco-Responsible Plasma Etching Processes
Traditionally used fluorinated gases, such as CF4 and C4F8, exhibit extremely high Global Warming Potentials (GWPs), significantly contributing to climate change. To address these environmental challenges, the project aims to promote the use of alternative low-GWP gases in combination with efficient exhaust abatement systems at the reactor outlet, while maintaining high-performance plasma etching processes. In this context, the postdoctoral researcher will be responsible for the analysis and characterization of gaseous species in an industrial plasma etching reactor using mass spectrometry. These measurements will be compared with the gas effluent at the outlet of the pumping and abatement systems. The main objectives are (i) to quantify the Destruction Removal Efficiency (DRE) of high and low GWP fluorocarbon gases during plasma processing and within the pumping and abatement stages, and (ii) to identify and propose innovative, environmentally responsible alternatives to minimize the release of high-GWP gaseous effluents.
Understanding and modeling the thermodynamic and kinetic properties of MOX fuel in future reactors
This study is part of the Sodium-Cooled Fast Reactor projects. Uranium and plutonium dioxide (U,Pu)O2, known as MOX, is the reference fuel. During operation, fuel pellets are subjected to a high thermal gradient that induces mass transport, thermodiffusion, and vaporization phenomena, coupled with irradiation effects. Fuel performance codes are developed to simulate the behavior of fuel rods under nominal and incidental conditions, up to and including meltdown.
The objective of this study is to improve the thermokinetic model of MOX used in these codes. This model is based on the description of the U-Pu-O system using the CALPHAD method, coupled with a database of element mobilities developed using DICTRA software. The description of defects will be extended with the introduction of metal vacancies and oxygen clusters. The description of thermodynamic data (oxygen potential and heat capacity) and the phase diagram will also be improved by taking into account the most recent data. Finally, the mobility database, coupled with the Calphad model, will be improved to better describe diffusion in MOX. New experimental data as well as data calculated using atomic-scale calculation methods (molecular dynamics, ab initio) will be used.
Development of an innovative instrumentation architecture using an array of magneto-resistive sensors to create a fast tomography system for fuel cells
Developing an innovative instrumentation architecture using an array of magneto-resistive sensors to create a rapid tomography system for fuel cells.
The goal is to develop a TRL 4 demonstrator in the laboratory to demonstrate a proof of
concept on a low-temperature fuel cell stack. This will include four measurement boards
with several dozen of synchronized magnetic sensors for simultaneous acquisitions. Experimental results and a description of the instrumentation system will be published. Historical data will be used to validate current density resolution algorithms and compare their performance to solutions based on Physics Informed Neural Network. Estimated current density results will be used for an additional publication.
The instrumentation system will be integrated into a CEA test bench dedicated to optimal control, transient observation, fault detection and exploration of defect propagation phenomena. This approach will offer dynamic and non-invasive observation of current distribution in the fuel cell, thereby improving the understanding of its operation and facilitating the optimization of its performance and lifespan.
Multipoint initiation of explosives. Experiments and simulations.
The design of high-performance and increasingly safe systems requires new solutions for initiating the explosives that make up their charge. One possible approach is to replace the electrical ignition of detonators with optical ignition in order to eliminate the risks associated with parasitic electrical sources.
Another possible way to improve safety is to use multipoint initiation so that the explosive only detonates when all initiation points are activated synchronously.
The objective of the postdoctoral contract will be to conduct an in-depth study of the mechanisms governing multipoint optical initiation. To this end, after conducting exhaustive bibliographic research, the candidate will propose the most relevant configurations and test them both experimentally and by performing hydrodynamic simulations using a code developed at the CEA. Understanding the phenomena involved is essential in order to be able to choose an initiation configuration suited to each need.
Diamond-based electrochemical sensors for monitoring water pollution in urban environments
This postdoctoral position is offered by CEA List as part of the European UrbaQuantum project ("A novel, Integrated Approach to Urban Water Quality Monitoring, Management and Valorisation"), part of the HORIZON-CL6-2024-ZEROPOLLUTION-02 call for projects. The main objective of this project is to develop, in response to climate change, sensors, models, and protocols for better management of the water cycle in urban environments.
At the Sensors and Instrumentation for Measurement Laboratory (LCIM)of CEA List the postdoctoral fellow will contribute to the development of electrochemical sensors based on synthetic diamond and associated measurement protocols for the detection of pollutants such as pharmaceuticals, heavy metals, PFAS, and pesticides. These sensors will be miniaturized and integrated into a microfluidic cell, in partnership with CEA-Leti, then tested under real-world field conditions.
Modelling of Drop Settling and Coalescence in Mixer-Settlers for Liquid–Liquid Extraction
The energy transition toward low-carbon technologies—such as Li-ion batteries, photovoltaics, and wind power—relies heavily on critical materials like rare earth elements (Dy, Nd, Pr) and metals (Co, Ni, Li). However, their extraction raises serious environmental concerns, and their recycling remains limited due to their low concentrations within complex waste streams, making separation particularly challenging.
Liquid–liquid extraction stands out as an effective technique for purifying such mixtures. Yet, its industrial deployment is hindered by an incomplete understanding of the underlying physico-chemical phenomena, particularly in mixer-settlers—compact devices that combine a mixing chamber with a gravity-based settling zone. While widely used for their high efficiency and compact footprint, current models describing these systems remain semi-empirical and focus mainly on the mixing phase, limiting their predictive capabilities at larger scales. Within the framework of the French national PEPR program "Recyclability and Reuse of Materials", the CEA is leading an initiative to develop a digital twin of mixer-settlers. This postdoctoral position contributes to that project, with a focus on modeling the settler unit. The researcher will conduct experiments using well-characterized emulsions injected into a dedicated transparent mock-up, to study droplet sedimentation and track size evolution over time. These experimental data will serve to validate a model that describes the gravitational and hydrodynamic transport of droplets, as well as coalescence and break-up phenomena. Ultimately, this model will be coupled with an existing model of the mixing chamber (currently under development in a parallel PhD project), leading to the creation of a first-generation digital twin of the complete device.
Design and development of a modular high-side test bench for application validation of Grand Gap components
Wide bandgap transistors (GaN, SiC) play a key role in power electronics, but their industrial integration remains hampered by implementation difficulties. The high-side component, within a bridge arm structure, is particularly sensitive to voltage and current transients, which are highly dependent on routing, topology, and switching modes (ZVS, ZCS). Its floating nature makes measurements complex and can disrupt switching during application testing. A methodology adapted to fast transients was developed during a thesis, resulting in a patented test bench for characterizing low-side components. The subject of the postdoctoral research presented here aims to adapt this methodology to high-side components, which are more complex to drive and measure, in order to characterize and model aging due to gate transients under realistic conditions. The test bench will enable the generation of reproducible stress profiles on low-side and high-side components, and the precise measurement of key parameters such as threshold voltage and dynamic instabilities. To achieve these objectives, a new bench will be designed, incorporating specific control and measurement systems, with a view to application testing and targeted aging tests.
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