jobs

An opportunity for a one year term as researcher is available at the Institut de Chimie Séparative de Marcoule in collaboration with Amphos 21 (Spain) and SKB (Sweden).

This offer is a part of a project developed since ten years at the ICSM, which was generally dedicated to the stability of coffinite mineral (USiO₄) (1-7). A major question was then raised whether coffinitization of the UO₂ will occur under the reducing conditions and silica-rich groundwater encountered in the vicinity of the long-term repository settings of spent nuclear fuel. Therefore, it is crucial to have accurate understanding of the mechanism of alteration and long term behavior of UO₂ in the presence of silicate ions in aqueous solution.

In this project, it is important to assess whether coffinite will control the U-concentration in solution. Two major tasks will be developed:

• a multiparametric study of the kinetics of dissolution of UO₂ in the presence of silicate ions in solution, 
• a thorough examination of the evolution of the solid/solution interface in order to obtain insights about the coffinitization process of UO₂ under various conditions.

Qualifications:

• PhD in inorganic chemistry or materials chemistry, working in controlled area will be greatly appreciated.
• Knowledge of the leaching/dissolution theory and experimental work (kinetics and thermodynamics).
• Strong skills in thermodynamic calculations over the use of the appropriate databases and speciation software.
• Characterization of solids, surfaces and interfaces by techniques such as PXRD, SEM, XPS.
• Ability to communicate in English with the different partners in France, Spain and Sweden.
• Ability for the various aspects of a research project: design of experiments, careful execution of work, interpretation of scientific data, writing of reports and scientific articles, participation in conferences, organizing and conducting meetings, compliance with deadlines.

Contact:

• Prof. Nicolas Dacheux (nicolas.dacheux ad umontpellier.fr)
• Dr. Stéphanie Szenknect (stephanie.szenknect ad cea.fr)

This project aims to develop a new methodology for the characterization of solid-liquid interfaces during the dissolution process, mainly focused on the 3D reconstruction of surfaces on the basis of tilted SEM image series. The 3D images will be recorded regularly during the sample dissolution in order to determine accurately the local quantities of dissolved matter. The studied materials will be model compounds that are of interest in several application fields: catalysis, solid oxide fuel cells, surrogates for the nuclear fuel. They will be chosen in the CeO₂-Nd₂O₃ binary system. This system allows preparing materials with variable crystal structures and microstructures, depending of the sample composition in order to adapt the dissolution kinetics to the sample observation techniques. In parallel with the methodological developments, numerical modelling based on image processing will be developed to link the local dissolved volumes (mainly related with the preferential dissolution) with the dissolution rates measured at the macroscopic scale.

Main responsibilities: As post-doc in this project you are responsible for elaborating the materials, recording the SEM image series and performing further 3D reconstruction, and building/developing the global dissolution model. The experimental results should be used as a basis for understanding and describing the dissolution processes on a submicro-level.

More information: https://euraxess.ec.europa.eu/jobs/254482