PhD position – Immobilisation of radium (226Ra) and strontium (90Sr) by carbonate minerals

We invite early-career researchers to apply for a PhD position within the joint research project “TRANSFER - Training and Research Academy for Nuclear Safety and Future Expertise on Geological Repository Systems”. As part of a structured doctoral program, you will conduct research on cutting-edge topics related to the disposal of high-level radioactive waste. TRANSFER is jointly funded by the German Federal Ministry for Research, Technology and Space (BMFTR) and the Federal Company for Radioactive Waste Disposal (BGE) and is coordinated by the GFZ German Research Centre for Geosciences.

Your Job

Carbonate minerals are present in many claystone formations and can contribute to the retention of radionuclides through co-precipitation, surface reactions or the formation of solid solutions. The aim of this PhD project is to gain a comprehensive understanding of the retention of the radionuclides 226Ra and 90Sr in carbonate-bearing claystones through a combination of experiments and simulations, and to elucidate the competition between sorption and co-precipitation processes, as well as the reversibility of these processes. Furthermore, the effects of heterogeneities in the mineral composition and distribution on radionuclide migration in clay rocks will be evaluated. The findings will contribute to the improvement of process models for the cross-scale description and simulation of radionuclide migration in the near- and far-field of a geological repository for high-level radioactive waste.

Your main responsibilities within the project will include:

Conducting sorption/desorption experiments to determine the retention of 226Ra and 90Sr in carbonate-bearing claystones and its reversibility
Conducting recrystallisation experiments to investigate the structural uptake of 226Ra into carbonate minerals
Analysing selected samples from sorption and recrystallisation experiments using advanced analytical methods such as Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and synchrotron-based methods (µ-XRF and µ-XRD)
Application of geochemical-thermodynamic modelling to interpret the experiments
Collaboration with modellers (reactive transport) to evaluate the migration behaviour of 226Ra and 90Sr in heterogeneous claystone formations across various spatial and temporal scales
Presentation of results at scientific conferences and in peer-reviewed publications

Your Profile

Master’s degree, Diplom or equivalent in chemistry, radiogeochemistry, environmental chemistry, geochemistry, chemical engineering, mineralogy or related field
Experience of working in wet chemical laboratories
Experience in geochemical or thermodynamic modelling is desirable
Ability to work collaboratively within a multidisciplinary and international team
Very good command of written and spoken English with extensive vocabulary is required (at least B2 level according to the ), ideally supported by a certificate confirming the language level

Our Benefits for You

We work on the very latest issues that impact our society and are offering you the chance to actively help in shaping the change! We offer ideal conditions for you to complete your doctoral degree:

A structured training programme: Within the TRANSFER graduate school on geological disposal, comprising seminars, summer and winter schools, participation in conferences, and the opportunity for research stays at partner institutions, aiming at a comprehensive understanding of nuclear waste management
Team & Environment: You will work in a motivated team with an international and interdisciplinary focus – at one of the largest research institutions in Europe
Research & Infrastructure: You will have access to excellent scientific and technical facilities for your work
Networking & Exchange: You will participate in (international) conferences and project meetings and actively build your scientific network
Supervision & Support: We will accompany your doctoral studies with continuous, expert guidance from your academic supervisor
Annual Leave: You get 30 days of annual leave
Knowledge & Development: Your professional development is important to us – we support you specifically and individually e.g., through training and networking opportunities specifically for doctoral candidates
Health & well-being: Your health is important to us. You can look forward to a comprehensive company health management programme with a wide range of options, including a beach volleyball court, running groups, yoga classes and much more. In addition, our company medical service and an experienced social counselling team are available to assist you on site
Campus experience: Our research campus in the countryside creates ideal conditions for collegial exchange and sporting activities right on site. Our cafeteria offers a wide range of options—you can enjoy a relaxing lunch break with a lake view
Successful start: It is important to us that you quickly settle into the team and are given structured training for your tasks. We also support you from the very beginning and make your start easier with our
Fair remuneration: Depending on your qualifications and assigned responsibilities, you will be classified according to pay group 13 (50%) of the TVöD-Bund. Additionally, you will receive a special payment (“Christmas bonus”). All information about the TVöD-Bund collective agreement can be found on the (pay scale table on page 66 ff. of the PDF download)
Support for international employees: Our International Advisory Service makes it easier for international employees to get started

In addition to exciting tasks and a collegial working environment, we offer you much more:

We welcome applications from people with diverse backgrounds, e.g. in terms of age, gender, disability, sexual orientation / identity, and social, ethnic and religious origin. A diverse and inclusive working environment with equal opportunities in which everyone can realize their potential is important to us.

The following links provide further information on diversity and equal opportunities: and on specific support options:

Place of Employment: Jülich

**Start Date:**To the next possible date

Salary: Pay group 13 (50%) of the TVöD-Bund

Application Deadline: The job will be advertised until the position has been successfully filled.