Missions

At the CNRS CEMHTI (Extreme Conditions and Materials: High Temperature and Irradiation) laboratory in Orleans, the "Materials and Magnetic Resonance" team is recruiting a researcher to work on the characterisation of materials by NMR spectroscopy and EXAFS (Extended X-Ray Absorption Fine Structure) at high temperature.
The ISAC (Innovative System for Actinide Conversion) project is based on a breakthrough technology: the Molten Salt Reactor (MSR). In this reactor, the fuel is liquid and also acts as a coolant. One of the major features of this reactor is that it is able to store the fuel and actinides almost continuously and to treat/purify the salt in situ. For this reactor to operate optimally, it is necessary to acquire in-depth knowledge of the chemistry and properties of the fuel salt, a multi-component system that exhibits non-ideal behaviour at the high temperatures used in the reactor. The aim of this project is to obtain baseline data and provide tools to predict the properties and behaviour of the salt in the reactor.
Various research projects carried out at the CEMHTI have led to the proposal of an approach combining various experimental analyses, such as EXAFS analysis at high temperature on fluorinated "molten salts" and high-temperature NMR, both using sealed, inert cells that are compatible with actinides, with molecular dynamics calculations. These have enabled different compositions based on 'simulants' and actinides to be analysed. In the case of the reactor designed today, a mixture of chlorides (NaCl-MgCl2-PuCl3-AmCl3) is used. Two approaches will be taken: the first will focus on the simulant system (cerium, lanthanum), enabling the cells to be set up and the various parameters of the experiment (temperature, cycling, duration of the experiment, sensitivity, etc.) to be checked and the second will focus on the transfer to the analysis of the same system but based on actinides. Collaboration with the CEA will make it possible to work in appropriate structures with a good knowledge of nuclear safety issues.
The person recruited will implement and develop the experimental approach in these molten media and will collaborate with the project partners. He/she will work with a doctoral student already recruited for the project, and will participate in scientific meetings and discussions to which he/she will contribute his/her expertise.

Activities

- Preparation of samples, conditioning in specific cells
- Discussion and interpretation of results
- Drafting/participation in the drafting of the experiment project, reports and publications
- Collaboration with ISAC project participants, in particular on the complementarity of numerical and spectroscopic approaches
- Possible travel for meetings or specific experiments on synchrotrons
- Promote results through publications and participation in conferences

Skills

- PhD in chemistry or physics (solid or materials)
- Proficiency in high-temperature experimentation
- Professional experience required: thesis and possible post-doctorates
- Independent control of experiments
- Good knowledge of NMR and EXAFS techniques.
- Mastery of IT tools for formatting and presenting scientific results, calculations and valorisation of experiments.
- Ability to work as part of a team: the post will involve meetings in the laboratory with the project team as well as collaboration with other laboratories.
- Thorough knowledge of health and safety regulations relating to the field of work.
- Promotion of research results orally and/or in writing, and by writing publications.
- Fluency in reading, writing and speaking English.
- Planning and implementation of research work within defined deadlines.

Work Context

The CEMHTI is a CNRS research unit located on two nearby sites (High Temperature and Cyclotron) and employing around 100 people.
The laboratory is developing original expertise and tools at national and international level to study the physico-chemical properties of materials in extreme conditions, particularly in situ.
The person recruited will be based at the laboratory's high-temperature site in the "Materials and Resonances: design, characterisation and applications" MATRMAG team. In addition to NMR measurements, he/she will participate in various EXAFS experiment slots on the SOLEIL (Saclay), ESRF (Grenoble) and Photon Factory (PF) synchrotrons at KEK (Tsukuba, Japan).

Constraints and risks

The activity related to the job profile will require some business travel depending on the health conditions in force.