Stephan Hilpmann (HZDR)

Stephan Hilpmann is a research associate at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), where he has been conducting research at the Institute of Resource Ecology since 2019. After studying chemistry at the Technical University of Dresden, where he earned a bachelor's degree (2016), a master's degree (2018), and finally a doctorate (2023), Hilpmann devoted himself to researching microbial processes in the context of radioactive waste disposal.

His work focuses on the interaction of the anaerobic, sulfate-reducing bacterium Desulfosporosinus hippei with uranium and europium, which is used as an analogue for other radioactive elements. Particularly noteworthy is his discovery of uranium(V) as an intermediate product of microbial reduction, which he was able to detect using synchrotron X-ray spectroscopy. This finding contributes significantly to the understanding of biogeochemical processes in potential final repository environments and supports the development of safe concepts for the long-term storage of radioactive materials.

For his outstanding dissertation, Stephan Hilpmann was awarded the Helmholtz Association's Doctoral Prize in the field of energy research in 2024. In an interview, we talked to him about his work and his motivation.

Interview:

What are you currently working on?

Stephan Hilpmann: 

The safe disposal of heat-generating high-level radioactive waste is one of the greatest challenges facing our society. At our institute, we research relevant physical, chemical, and biological processes that can occur in a repository. This enables us to generate important insights for the most comprehensive and reliable safety assessment of repository systems possible.

I am currently working on the question of how certain radioactive elements and their analogues (especially trivalent lanthanides and actinides) behave on mineral surfaces. Such processes would be important, for example, in a worst-case scenario, i.e., if water were to enter the repository. We are investigating how effectively different types of rock can retain these substances and which factors influence this process.

During my doctoral studies, I previously researched the influence of microbial activity on the migration of radionuclides. Microorganisms naturally occur in deep rock layers and can influence the spread of radionuclides underground.

I find it particularly exciting that I can investigate both biogeochemical and geochemical issues at our institute. This gives me a holistic view of the processes that could take place in a final repository and how they influence safety.

What is your personal motivation?

Stephan Hilpmann: I have always found it fascinating that the profession of researcher enables the creation of new knowledge. It is precisely this new knowledge that is also of utmost importance for final storage research. Many people in Germany are very interested in this topic, as everyone wants to be protected from the dangers of radioactive waste. Being able to contribute to this motivates me greatly.

In addition, working with other scientists, doctoral students, and postdocs is very enriching for me. This exchange provides new food for thought, which greatly benefits my own research. That's why I wouldn't want to give up working in an international team. It is a great enrichment for me, both professionally and personally.

What kind of challenges are ou facing in the near future?

Stephan Hilpmann: As I am still at the beginning of my academic career, my biggest challenge in the near future will be to find my place in the academic world. This includes further developing my academic profile, gaining new research experience, including internationally, and searching for suitable funding opportunities. I plan to apply for various grants and fellowships that will enable me to take these steps. In order to accomplish this alongside my current research, efficient time and resource management is crucial.

If you could make a wish for something for your research, what would you wish for?

Stephan Hilpmann: For my research, I would like to see the results and findings we obtain in the field of final storage research actively incorporated into political decision-making so that a science-based site selection process becomes possible. This is the only way we can determine the safest site for high-level radioactive waste. In general, I would like to see broad social trust in this process, but also in science in general. I believe that a strong interdisciplinary approach is crucial, especially in final repository research, and that this approach should be further expanded in the future in order to provide well-founded answers to these important questions. In addition, I hope to continue my scientific career in the long term and to continue contributing to this important field of research. My goal is to gradually establish myself in the scientific world.

Where do you see your discipline in 5-10 years?

Stephan Hilpmann: In five to ten years, I envision that our research in the field of final repository siting will have provided us with a much deeper understanding of the processes that can occur underground in potential final repository systems. My goal is for our findings to be firmly incorporated into safety analyses by then, thus forming an important basis for site selection in Germany and internationally. An important step in this process will be the creation and expansion of comprehensive databases into which the research results are systematically incorporated and on the basis of which science-based decisions can be made. I hope that my work will contribute to further reducing uncertainties and strengthening society's confidence in the site selection process.

ORCID: 0000-0001-7906-6851