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PhD student (M/F) - Impact of irradiation on the chemical durability of U1-xThxO2 and U1-xCexO2sintered pellets

This offer is available in the following languages:
Français - Anglais

Date Limite Candidature : mercredi 14 juillet 2021

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General information

Reference : UMR9012-REJBOD-030
Workplace : ORSAY
Date of publication : Wednesday, June 23, 2021
Scientific Responsible name : Frederico GARRIDO / Claire LE NAOUR, Clotilde GAILLARD
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 October 2021
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly

Description of the thesis topic

The project lies within the framework of the Chemistry of the nuclear fuel cycle and reprocessing of MOX fuels. It deals with the impact of irradiation on the chemical durability of fuels. Indeed, irradiation strongly modifies the microstructure and composition of fuels: fission fragments emitted during the fission, alpha decay of actinides generated by neutron captures and neutron bombardment are responsible for radiation damage on the crystalline structure. Depending on the physical nature of interaction processes (atomic or electronic collisions), irradiation-induced effects can be experimentally simulated by using energetic ion beams. Pellets as model systems (U1-xThxO2, U1-xCexO2, U1-xNdxO2) will be irradiated under various damaging regimes (nuclear or electronic energy loss) at the JANNuS-SCALP facility located at Orsay and at GANIL-Caen, and then submitted to multiparametric dissolution tests to identify and to class contributions from the various relevant parameters. The objective of the PhD work will be to understand the role played by the incorporation of tri- and tetravalent elements embedded in the matrix on the chemical durability of the solid and the impact of irradiation and microstructural modifications on the mechanisms and rates of dissolution processes. Effects of acidity and nature of the solution, redox potential, temperature that influence the uranium speciation will be examined separately. Solid pellets will be characterized by various techniques (SEM, Raman spectroscopy, ion beam analysis) and the solution by ICP-AES and PERALS (Photon Electron Rejecting Liquid Alpha Spectroscopy). Spectroscopic techniques (UV-VIS absorption spectrophotometry, IR spectroscopy, TRLIFS (Time-Resolved-Laser-Induced-Fluorescence Spectroscopy)) will be carried out to carefully characterize the speciation of soluble species.
Research results will be published in peer reviewed scientific journals (A ranking) and the PhD student will be in charge to present results at international conferences.

Work Context

IJClab is a joint research unit of CNRS, Université Paris-Saclay and Université de Paris located on the Orsay campus, recently formed by the merger of 5 laboratories (CSNSM, IMNC, IPNO, LAL and LPT). The PhD student will be a member of the CHIMèNE (Chemistry, Irradiation, Materials, Modelling, Electrochemistry, for Nuclear energy and Environment) and RAPHYNEE (Radiochemistry and Nuclear Physics for Energy and Environment) teams within the Energy and Environment pole. The pole Energy & Environment comprises about 40 chemists and physicists (including permanent researchers, post-docs and doctoral students). The PhD will be conducted in close collaboration with the IP2I at Lyon in the ACE (Aval du Cycle Electronucléaire) team and the LIME team at the ICSM laboratory at Marcoule. The PhD student will be registered at the Doctoral School PHENIICS (ED 576) of the Université Paris-Saclay, in the major Nuclear Energy. The PhD student will work on at the building dedicated to the chemistry of actinides and at the JANNuS-SCALP platform in Orsay Campus.

Constraints and risks

The successful candidate shall be enrolled on a PhD program of the PHENIICS doctoral school (ED 576). Daily work is located at the Orsay campus. Research travels will be necessary to perform experiments at IP2I-Lyon, at the GANIL accelerator located at Caen and at ICSM Marcoule.

Additional Information

The candidate must have a Master degree or an Engineering diploma (with master) in Chemistry of Physico-chemistry, preferably in relation with the nuclear field. The position requires a high level of experimental skills. We are looking for a PhD fellow who will be able to become fully involved with the project, a certain independence of thought, a strong motivation, able to work in a team on multi-disciplinary projects. Good level of communication skills, both oral and written (French and English required) are necessary to perform presentation at progress meetings and conferences and to write articles in scientific journals.

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