EESS talk on "Leveraging microbial processes to mitigate H2 build-up in radioactive waste repositories"

Nuclear energy is an important part of the global energy supply, but managing its long-lived waste remains a challenge. Deep geological repositories are considered the most reliable solution, yet hydrogen gas (H₂) from the corrosion of steel waste containers can build up and create pressure that threatens the stability of the host rock. Gas-permeable backfill materials can reduce this pressure mechanically, but microbial use of H₂ may offer an additional, cost-effective safety measure. In experiments simulating repository conditions, we found that pressure dropped quickly due to microbial H₂ oxidation involving multiple metabolic pathways. Water and electron acceptor availability were key factors controlling this process. These results highlight the conditions that regulate microbial H₂ oxidation in unsaturated porous media and provide insights for improving safety assessments of geological repositories.

I completed both my bachelor’s and master’s degrees in Energy and Environmental Engineering at INSA Lyon. After an initial research project on the photocatalytic reduction of CO₂ using semiconductors (DTU Department of Energy Conversion and Storage), I realized I was more interested in environmental science, particularly in disentangling biological contributions to environmental cycles. This led me to EPFL, where I conducted my master’s thesis at the River Ecosystems Laboratory, studying the fate of organic matter in alpine catchments as part of the METALP project. Currently, I am a fourth-year PhD student in the Environmental Microbiology Laboratory, where my research focuses on the role of hydrogenotrophic microorganisms as key drivers of long-term stability in deep geological repositories.