PhD in Radiochemistry (M/F)

Job Description

Thesis Subject

Mechanistic Study of Radionuclide Lability and Reactive Site Accessibility in Soil Insoluble Organic Matter under NORM/TE-NORM Conditions

Insoluble organic matter represents a major fraction of soil organic carbon and plays an important role in contaminant retention. However, the mechanisms controlling the long-term fate of naturally occurring radionuclides within this matrix remain poorly understood. In particular, the processes responsible for the progressive decrease in their mobility over time (“ageing”) are still largely unknown.

The objective of this PhD project is to determine how the organization and accessibility of reactive sites within insoluble organic matter influence the mobility of naturally occurring radionuclides. The work will combine long-term incubation experiments, the monitoring of radionuclide lability through desorption-based approaches, the characterization of reactive sites using isotopic exchange and solid-state NMR, and the investigation of the influence of microbial activity on the evolution of these properties.

The PhD work will involve:

Setting up controlled incubations of radionuclide-doped insoluble organic matter under environmentally realistic geochemical conditions;
Determining labile and inert radionuclide fractions at different incubation times using complementary desorption methods;
Applying and optimizing a minimally intrusive vapor-phase isotopic exchange method (²H/¹H and/or ³H/¹H) to quantify the accessibility of reactive sites within insoluble organic matter;
Assessing the potential influence of microbial activity through parallel incubations under biologically minimized and biologically stimulated conditions.

Your Work Environment

The PhD project will be primarily carried out at the Subatech laboratory (Nantes, France), in close collaboration with ASNR (LT2S, Cadarache) for desorption and incubation experiments, and with CEA/BIAM for the microbial activity component. At the interface between environmental radiochemistry, soil geochemistry and microbial ecology, this research will contribute to improving our understanding of the mechanisms controlling long-term radionuclide retention in soils impacted by uranium mining activities and, more broadly, in NORM/TE-NORM environments.

The candidate must:
- Hold a Master's degree or equivalent in the field of radiochemistry and/or analytical chemistry.

The candidate must:
- Demonstrate strong motivation, curiosity and autonomy.
- Have a good command of English.
- Be able to write scientific reports and present results orally.
- Be able to work both independently and collaboratively within an international team environment.

Constraints and risks

Work in restricted areas, handling chemicals, field trips

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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