Reference : UMR8181-OLITOU-004
Workplace : VILLENEUVE D ASCQ
Date of publication : Wednesday, July 27, 2022
Scientific Responsible name : Olivier TOUGAIT
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 October 2022
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
In nuclear power plants, the cladding material undergoes physico-chemical transformations. An internal oxidation layer is formed which is contaminated with radioelements. During the reprocessing of spent fuel, the cladding materials are separated from the dissolution solutions and rinsed. In order to reduce the activity of these shells, it appears interesting to remove this oxidation layer. The objective of this thesis is to study the most promising way to meet these expectations, namely chemical stripping in molten salt media.
This thesis is part of an R&D project dedicated to the study of a way to optimise the management of irradiated assembly materials.
The work of the thesis will focus on laboratory scale studies of oxidation layer dissoluition in molten salt media. The candidate will be responsible for optimising the operating parameters on inactive samples in order to provide the necessary data for the development of a pilot unit. The methodology, already tested, will be based on chemical analysis by ICP-AES, structural analysis by RAMAN spectroscopy and X-ray diffraction, microstructural analysis by optical and electron microscopy (SEM/EDS) and thermal analysis by ATG coupled with mass spectrometry. In order to understand the behaviour of the reagents with irradiated samples, irradiation tests will be performed on the selected salt(s) and the candidate will use simulants to predict the behaviour of the contaminants. Finally, the suitability of the potential salts for cycling as well as the purification of the retained salt from dissolved contaminants will be investigated and a bath recycling route will be proposed and tested via long-term tests.
The person recruited will be part of the Regain R&D project financed under the PIA4-France-Relance programme, which brings together Orano-CEA-CNRS-Framatome and whose objectives are to develop innovative solutions for the reuse, recycling and recovery of zirconium-based materials from the nuclear industry. More specifically, the recruited candidate will work with the researchers specialised in reprocessing by a pyrochemical route of the UCCS (Unité de Catalyse et de Chimie du Solide, UMR CNRS 8181). For the purposes of the project, the selected PhD student will have access to all the materials characterisation platforms and the technology platform dedicated to nuclear materials at the Institut Chevreul.
- Graduate of a general engineering school with a specialisation in process chemistry or materials or a Master's degree in chemistry or materials science preferred but candidates with a Master's degree in physics or process engineering will also be considered.
- Ability to work in research teams with complementary skills as well as independently
- Curiosity, ingenuity and open-mindedness towards other fields,
- A good command of English to communicate results both orally and in writing.
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