Eng. Barriers for Geo. Disposal of Rad. Waste - Microbial interactions & their limits with THM-Chemical Processes at the Canister/Bentonite Interface
Lead Research Organisation:
Newcastle University
Department Name: Sch of Engineering
Abstract
Geological disposal of radioactive waste requires the development of a multi-barrier system to protect the waste in the long term. In this system an impermeable barrier of bentonite clay will surround steel waste canisters. Our previous work examined the geochemistry associated with steel corrosion and its effect on the bentonite's geotechnical properties. While barrier integrity was not considered an issue, results suggested that environments suitable for microbial activity may be possible at barrier interfaces with unknown consequences. This project will investigate the range and environmental limits of microbial interactions within such storage infrastructure, specifically in terms of corrosion, geotechnical properties and general metabolic functions in the context of long term geochemical and physical developments.
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/N509528/1 | 01/10/2016 | 31/03/2022 | |||
| 1948823 | Studentship | EP/N509528/1 | 01/10/2017 | 31/03/2021 | Katie Gilmour |
| Description | Key findings include: identifying indigenous microbes to MX80 bentonite which are thermotolerant / iron-reducing / spore forming. These are ideal candidates for survival in a nuclear waste repository and could interact with clay minerals or canister surface to disrupt the barrier system. Further tests with this community found that it can withstand high salinities of up to seawater level and some species present can survive up to 70C. Microbial secretions and metabolites were found to interact with iron minerals geographically distant from the microbes by being able to travel through pore spaces in the clay (0.02um). There is evidence to suggest these microbial activities can change the redox state and solubility of the iron. It was found that when microbes are liberating silica from the clay matrix - dissolved silica in groundwater was significantly higher when microbes were present. Geomechicanically, the plasticity index of the clay was lower when microbes were present in all scenarios when compared to a sterile control. Therefore this study found that microbes would negatively affect MX80 bentonite in its role as a barrier to nuclear waste - the extent of this is not clear. |
| Exploitation Route | Papers currently being compiled. Research has direct applications to nuclear waste storage and repository construction. |
| Sectors | Construction,Environment,Government, Democracy and Justice,Manufacturing, including Industrial Biotechology |
| Title | Indigenous microbial community of MX80 bentonite after iron-reducing enrichments |
| Description | Sequencing of the indigenous community of MX80 bacteria from both commercial compacted MX80 and raw powder MX80 following iron-reducing enrichments. Available on NCBI, project number: PRJNA594313. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| Impact | Essential for understanding microbial interactions. Increases understanding of which microbes will be present in nuclear waste repository. |
| Description | Pint of Science Festivals (event organiser) |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Public/other audiences |
| Results and Impact | Pint of science is an international festival which takes place every year in May. Over the last three years I have been involved in various roles, including event organiser, event host, "meet the scientist" speaker, and media coordinator. This has allowed me to interact with other scientists from both similar and unrelated fields, and engage with the general public and discuss my research with them. Public interaction resulted in lengthy discussions resulting in increased awareness of nuclear waste storage issues. |
| Year(s) Of Engagement Activity | 2018,2019,2020 |