crystals

Project: Assessment of microbial impact on mineralogical trapping of radioactive contaminants from groundwaters

The project focuses on understanding of uranium redox and retention pathways during uranium interaction with secondary minerals mediated by abiotic and microbial species in deep granitic rock-groundwater systems relevant to geological repositories for spent nuclear fuel.

Project information

Project manager
Ivan Pidchenko
Participating organizations
Linnaeus University; Swedish Nuclear Fuel and Waste Management Company (SKB)
Financier
EU, Marie Skłodowska-Curie Fellowship (MSCA-IF)
Timetable
1 Jun 2021–31 May 2023
Subject
Environmental Science (Department of Biology and Environmental Science, Faculty of Health and Life Sciences)

More about the project

One of the most serious environmental concerns is the wide occurrence of radionuclides in natural and anthropogenic environments and safe management of spent nuclear fuel (SNF), generated by nuclear facilities. The key factor for the safe operation of a geological repository is an oxygen-free environment in groundwaters to retard the degradation of SNF and release of radioactive constituents. Essential are the minerals precipitating directly from the groundwater flow paths that act as scavengers for contaminants through multiple removal mechanisms. For example, the main constituent of SNF, uranium, and other important trace metals can be trapped by secondary minerals in terrestrial deep surface environments.

Redox processes play key roles in the (bio)geochemical mobility of numerous trace elements including uranium. Uranium redox processes are associated with isotope fractionation of its long-lived radioisotopes 238U and 235U. The isotope fractionation varies in magnitude and direction when mediated either by abiotic species and/or microorganisms. While most studies are done in static laboratory settings or on complex natural systems, multiple effects of abiotic and microbial species on uranium retention and isotope fractionation are not explored. Moreover, dynamic hydrogeochemical parameters are not considered and/or are often difficult to model. These are crucial parameters for the long-term safety assessment safety of deep crystalline rock nuclear repository and require integration of reliable reactive transport models.

The main objective of the project is to increase understanding of uranium redox and retention pathways during uranium interaction with secondary minerals mediated by abiotic and microbial species in deep granitic rock-groundwater systems. The main research tasks of the project will be achieved by implementing a comprehensive experimental approach involving the study of isotope proxies in deep fracture minerals and groundwaters, integration with microbiological studies, synchrotron investigations, and hydrogeochemical modelling, the cross-correlation between natural and laboratory studies. Project results are useful to (bio)geochemists, environmental scientists, site remediation engineers, hydrologists, and microbiologists from academic and industrial fields. The communication, guidance and supporting activities are directly arranged by several environmental agencies and research institutes.

The project is part of the research in the Environmental Geochemistry research group.