Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

PhD : selection by topics

Technological challenges >> Chemistry
2 proposition(s).

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Development of uniform surface sources by functionalization for decommissioning & dismantling

Département Métrologie Instrumentation et Information (LIST)

Laboratoire de Métrologie de l'Activité

01-10-2020

SL-DRT-20-1058

valerie.lourenco@cea.fr

The decommissioning of nuclear installations and the management of the radioactive waste produced during this stage are major concerns for the future, especially with the ageing of the European nuclear plants. Improving the qualification of contamination assessment systems would make it possible to analyse more precisely and ideally identify more quickly the the appropriate waste management channel to help control the resulting costs. The thesis topic focuses on widespread cases where the activity is present on/in surfaces, flat or curved, as well as in pipes. The objective of the thesis is to realize uniform, traceable, flat or cylindrical surface sources, even deformable, with limited radiation attenuation (case of pure beta or alpha emitters). The added value associated with the traceability of these sources lies in the control of the deposited activity level, whatever the radionuclide considered. The approach adopted is the functionalization of a substrate to immobilise and distribute the radionuclides uniformly without excessive attenuation of the radiation emitted, while ensuring that the surface remains non-contaminating. The formation of strong chemical bonds with the surface will guarantee the stability of the layer formed and the chemical affinity with the grafted complexing molecules aims to permanently immobilise the activity. The choice of the functionalization method depends on the substrate on which the bonding takes place (metallic, polymeric, conductive or non-conductive, flexible or rigid). The other end of these molecules can be functionalized to make them specific to the target radionuclides. The tests of surface sources will be carried out first with Am-241, both alpha and low energy gamma emitter and pure beta or not emitters of interest for the elaboration of typical waste spectra. The problem of large surfaces and especially the criterion of source uniformity (variability of surface activity < 10 %, including uncertainties), constrain the method to be used for the functionalization of the surface. The evaluation of the uniformity of the activity distribution over the source surface will be carried out by autoradiography (imaging technique whose signal is proportional to the activity).

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Reliable metal organic frameworks (MOF) and derivatives for radioactive gas detection

Département Métrologie Instrumentation et Information (LIST)

Laboratoire Capteurs et Architectures Electroniques

01-10-2020

SL-DRT-20-1117

guillaume.bertrand@cea.fr

This PhD position will be carried out in the frame of the SPARTE European project, which aims at developing porous scintillators in order to detect radioactive gases. The main goal of this PhD thesis is to explore the rich family of Metal Organic Frameworks (MOFs), and specifically the ones with fluorescent organic building blocks. The study will follow good preliminary results that our team got with Zinc-based MOFs and MOFs derivatives. We would like to extend the scope of these good results to other porous frameworks. Synthesis of new fluorescent ligands will also be considered. Photophysical properties of these materials will also be explored as well as their ability to concentrate and detect radioactive gases. This last measurement will be performed on a unique in the world labmade radioactive-gas bench. The PhD candidate is expected to perform inorganic solvothermal synthesis as well as photophysical characterization. He/she will also work on the radioactive gas bench set up. We wish to recruit somebody with a strong background in inorganic or organic chemistry and an open mind towards material-science technics. This thesis will be performed in two different laboratories, with two technical supervisers (Guillaume BERTRAND - LCAE and Benoît SABOT - LNHB/LMA) and a PhD director (Matthieu HAMEL - LCAE).

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