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Impact of compacted bentonite microbial community on the clay mineralogy and copper canister corrosion: a multidisciplinary approach in view of a safe Deep Geological Repository of nuclear wastes

Marcos F. Martinez-Moreno, Cristina Povedano-Priego, Mar Morales-Hidalgo, Adam Mumford, Jesus Ojeda Ledo Orcid Logo, Fadwa Jroundi, Mohamed L. Merroun

Journal of Hazardous Materials, Volume: 458

Swansea University Authors: Adam Mumford, Jesus Ojeda Ledo Orcid Logo

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Abstract

The Deep Geological Repository (DGR) is the preferred option for the final disposal of high-level radioactive waste. Microorganisms could affect the safety of the DGR by altering the mineralogical properties of the compacted bentonite or inducing the corrosion of the metal canisters. In this work, t...

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Published in: Journal of Hazardous Materials
ISSN: 0304-3894 1873-3336
Published: Elsevier 2023
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa63710
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Abstract: The Deep Geological Repository (DGR) is the preferred option for the final disposal of high-level radioactive waste. Microorganisms could affect the safety of the DGR by altering the mineralogical properties of the compacted bentonite or inducing the corrosion of the metal canisters. In this work, the impact of physicochemical parameters (bentonite dry density, heat shock, electron donors/acceptors) on the microbial activity, stability of compacted bentonite and corrosion of copper (Cu) discs was investigated after one-year anoxic incubation at 30 ºC. No-illitization in the bentonite was detected confirming its structural stability over 1 year under the experimental conditions. The microbial diversity analysis based on 16S rRNA Next Generation Sequencing showed slight changes between the treatments with an increase of aerobic bacteria belonging to Micrococcaceae and Nocardioides in heat-shock tyndallized bentonites. The survival of sulfate-reducing bacteria (the main source of Cu anoxic corrosion) was demonstrated by the most probable number method. The detection of CuxS precipitates on the surface of Cu metal in the bentonite/Cu metal samples amended with acetate/lactate and sulfate, indicate an early stage of Cu corrosion. Altogether, the outputs of this study help to better understand the predominant biogeochemical processes at the bentonite/Cu canister interface upon DGR closure.
Keywords: DGR; compacted bentonite; microbial diversity; sulfate-reducing bacteria; copper corrosion
College: Faculty of Science and Engineering
Funders: The present work was supported by grant RTI2018-101548-B-I00 from MCIN/AEI/10.13039/501100011033 “ERDF A way of making Europe” to MLM from the “Ministerio de Ciencia, Innovación y Universidades” (Spanish Government) and JJO/ADM acknowledge funding from the UK Engineering and Physical Sciences Research Council (EPSRC) DTP, project reference: 2748843.