Development of isotopic and elemental analysis methods on irradiated fuels for the reduction of sample quantities.
The objective of this postdoctoral research is to develop analytical methods for the overall reduction of sample quantities required for high-precision multi-element isotopic analysis (actinides and PF) of spent nuclear fuel, particularly through the use of novel "low-quantity" introduction methods on multi-collector ICPMS. These developments will notably reduce the amount of radioactive waste (consumables and effluents), the dose rate, and the exposure time of analysts/radioactive samples associated with this type of measurements.
To carry out this project, the candidate will conduct analytical developments in a controlled environment to minimize the quantities of elements required for analysis while maintaining or improving uncertainty levels compared to currently available methods.
Miniaturised analytical method dedicated to the screening of candidate molecules for the capture and removal of radionuclides
This project aims at developing a miniaturized multiplex device dedicated to the screening of the chelating ability of potential molecules for the decorporation of certain radionuclides (RN) from the nuclear power industry, for which current treatments are not satisfactory. The objective is to accelerate the identification of the most promising chelating molecules, while benefiting from the advantages of miniaturisation, such as the consumption of very small quantities of molecules and RN. In a previous project, a phosphated monolith of various lengths has been grafted in situ and characterised in capillaries of 100 µm internal diameter. The quantities of UO22+, Zr4+, Sr2+, Co2+, Cs+ and Ag+ immobilised on these monolithic phases have been measured online by coupling to an ICP-MS.Based on this work, the candidate will be responsible for developing and validating the miniaturised screening method with UO22+, for which data and chelating molecules are available, extending the approach primarily to Zr4+, Sr2+, Co2+, and to fabricate the microfluidic device incorporating parallel microchannels, in order to ultimately screen candidate molecules for distinct RNs in a single fluidic microsystem.
Microfluidics applied to the separation of actinides in nuclear samples by chromatography
The main objective of this post-doctoral position is to develop a method for separating the fission products, plutonium and uranium in nuclear samples by chromatography with a resin volume of 200 µL or less. This project is structured around three research axes.
The first one consists in optimising the miniaturised separation method. The resin packing protocol, the pressure applied during the separation and the eluant compositions will be studied by comparing the chromatograms and by calculating the associated decontamination factors. These developments will be carried out using simulated samples first, and then with plutonium-containing samples. Control over the redox adjustment step will be necessary to maximize the decontamination factors. A second development axis will focus on the conception of a user-friendly system, minimizing interventions in the glovebox in order to reduce the user's exposition to ionizing radiation. The experience of the laboratory in terms of experimental setup miniaturisation and micro-fabrication will be useful for this post-doctoral position. The third research axis consists in applying the developments of the first two axes to the determination of isotopic composition of nuclear samples by TIMS or MC-ICP-MS with a per-mil level of uncertainty in a radiation-controlled laboratory.
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.
Separation microsystem coupled to mass spectrometry for on-line purification and characterisation of nuclear samples
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.
Leaching foams to extract metals from electronic waste
The subject is part of the ANR "Foamex" project covering TRL from 1 to 5 and focussing on the development of recycling of some metals from a shred of electronic cards, this recycling being carried out in a fluid foam (minimization of the volume of solvents) that can be considered at the first level as a dynamic chromatography column. The principle is to use the foam as a reservoir containing an acid solution and specific oxidizing agents to dissolve and extract metals in the form of ionic species, a phenomenon enhanced by friction between bubbles and simultaneously to concentrate them via the fluid and mobile liquid/air interfaces by flow.
Development of methods for U quantification in cells after exposure to uranium
This project fits into the transverse Toxicology Program, led by CEA, whose purpose is to address by multidisciplinary approaches, the potential effects on living organisms of elements of strategic interest to the CEA. The objective is to provide some understanding on the mechanisms of uranium toxicity and behavior, in connection with its speciation in cells. Indeed, the radionuclides speciation governs their bioavailability, accumulation, biodistribution, toxicity, detoxification mechanisms and their interaction at the molecular level.
The post-doctoral project (12 months) consists in:
- Developing methods to quantify U accumulated in the cells as well as endogenous content of trace elements after exposure of cells to uranium.
- Developing methods to determine the precise isotopic composition of U in the cells after their exposure.
The candidate will be in charge of developing chemical purification and measurement methods for precise elemental and isotopic analyses. The analyses will be performed using inductively coupled plasma quadrupole mass spectrometer (ICP- MS Q) or inductively coupled plasma multi- collection mass spectrometer of the latest generation (ICP- MS MC), to achieve the lowest level of uncertainties.
Gas sensors based on diamond nanoparticles and nanoporous materials
The aim is to develop surface acoustic wave sensors (SAW) with high sensitivity and high selectivity to gaseous compounds (< 100 ppb). The development strategy involves the use of diamond nanoparticles based guiding layers deposited on the piezoelectric substrate and chemically modified to tune the specificity of the sensors. In order to increase further the selectivity, the sensors will be coupled to specific filters placed before the sensors and based on probe molecules trapped in porous sol-gel based materials and able to react non-reversibly with interferent molecules. The topic includes 4 mains sections: 1) synthesis and functionalisation of diamond nanoparticles, 2) study of probe molecules and immobilisation in porous matrices, 3) study of the filtering capacity of the filters toward relevant interferent species, 4) metrology and calibration of the sensors. This work will be carried out in the "Diamond Sensors Laboratory" as well as laboratoire Francis Perrin both located in CEA Saclay.