Modelling key reactive processes relevant to bisulfide transport through highly compacted bentonite
The Canadian deep geological repository (DGR) design consists of copper coated used fuel containers (UFCs) placed within a highly compacted bentonite (HCB) buffer surrounded by a suitable host rock. Although the copper is thermodynamically stable in oxygen-free environments, it is potentially suscep...
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Elsevier
2024-12-01
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| author | Md Abdullah Asad Tarek L. Rashwan Ian L. Molnar Mehran Behazin Peter G. Keech Magdalena M. Krol |
| author_facet | Md Abdullah Asad Tarek L. Rashwan Ian L. Molnar Mehran Behazin Peter G. Keech Magdalena M. Krol |
| author_sort | Md Abdullah Asad |
| collection | DOAJ |
| description | The Canadian deep geological repository (DGR) design consists of copper coated used fuel containers (UFCs) placed within a highly compacted bentonite (HCB) buffer surrounded by a suitable host rock. Although the copper is thermodynamically stable in oxygen-free environments, it is potentially susceptible to microbiologically influenced corrosion from bisulfide (HS-). Therefore, understanding HS- corrosion is important to ensure long-term performance of UFCs. Various reactions in the bentonite barrier of the DGR can affect HS- transport through the HCB and therefore the extent of copper corrosion caused by HS-. Since HS- transport and reactive processes are interconnected, numerical models are required to assess the complex HS- reactive transport dynamics and quantify the influence of reactive processes on HS- transport and corrosion. In this paper, various HS- transport models were coupled with (i) a key geochemical reaction between HS- and iron (i.e., simulating HS- retardation due to iron sulfide formation) or (ii) HS- adsorption. Since HS- is an anion, anion exclusion was also explored. Valuable insight was obtained through validation, comparison, and sensitivity analyses of these models. A comparison between experimental and modelled HS- transport dynamics showed that HS- is being retained by the bentonite due to reactive processes and anion exclusion is occurring. Lastly, HS- transport was simulated for the entire DGR lifespan and was found to be delayed (≈50–800 years) due to FeS formation or HS- adsorption. However, these predicted HS- diffusion delays are relatively short in a DGR lifespan (i.e., 1 million years) and do not impact long-term HS- corrosion. |
| format | Article |
| id | doaj-art-a2a55e8fa31e4a2aa43f0e1212659af7 |
| institution | DOAJ |
| issn | 2590-1230 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Results in Engineering |
| spelling | doaj-art-a2a55e8fa31e4a2aa43f0e1212659af72025-08-20T02:52:27ZengElsevierResults in Engineering2590-12302024-12-012410348610.1016/j.rineng.2024.103486Modelling key reactive processes relevant to bisulfide transport through highly compacted bentoniteMd Abdullah Asad0Tarek L. Rashwan1Ian L. Molnar2Mehran Behazin3Peter G. Keech4Magdalena M. Krol5Department of Civil Engineering, Lassonde School of Engineering, York University, Toronto, Ontario, M3J 1P3, CanadaDepartment of Engineering and Innovation, The Open University, Milton Keynes, MK76AA, United KingdomSchool of Geosciences, University of Edinburgh, Edinburgh, Scotland, EH8 8AQ, United KingdomNuclear Waste Management Organization, Toronto, Ontario, M4T 2S3, CanadaNuclear Waste Management Organization, Toronto, Ontario, M4T 2S3, CanadaDepartment of Civil Engineering, Lassonde School of Engineering, York University, Toronto, Ontario, M3J 1P3, Canada; Corresponding author.The Canadian deep geological repository (DGR) design consists of copper coated used fuel containers (UFCs) placed within a highly compacted bentonite (HCB) buffer surrounded by a suitable host rock. Although the copper is thermodynamically stable in oxygen-free environments, it is potentially susceptible to microbiologically influenced corrosion from bisulfide (HS-). Therefore, understanding HS- corrosion is important to ensure long-term performance of UFCs. Various reactions in the bentonite barrier of the DGR can affect HS- transport through the HCB and therefore the extent of copper corrosion caused by HS-. Since HS- transport and reactive processes are interconnected, numerical models are required to assess the complex HS- reactive transport dynamics and quantify the influence of reactive processes on HS- transport and corrosion. In this paper, various HS- transport models were coupled with (i) a key geochemical reaction between HS- and iron (i.e., simulating HS- retardation due to iron sulfide formation) or (ii) HS- adsorption. Since HS- is an anion, anion exclusion was also explored. Valuable insight was obtained through validation, comparison, and sensitivity analyses of these models. A comparison between experimental and modelled HS- transport dynamics showed that HS- is being retained by the bentonite due to reactive processes and anion exclusion is occurring. Lastly, HS- transport was simulated for the entire DGR lifespan and was found to be delayed (≈50–800 years) due to FeS formation or HS- adsorption. However, these predicted HS- diffusion delays are relatively short in a DGR lifespan (i.e., 1 million years) and do not impact long-term HS- corrosion.http://www.sciencedirect.com/science/article/pii/S2590123024017389Deep geological repositoryUsed nuclear fuelsNumerical modelsReactive processesBisulfide transportSorption |
| spellingShingle | Md Abdullah Asad Tarek L. Rashwan Ian L. Molnar Mehran Behazin Peter G. Keech Magdalena M. Krol Modelling key reactive processes relevant to bisulfide transport through highly compacted bentonite Results in Engineering Deep geological repository Used nuclear fuels Numerical models Reactive processes Bisulfide transport Sorption |
| title | Modelling key reactive processes relevant to bisulfide transport through highly compacted bentonite |
| title_full | Modelling key reactive processes relevant to bisulfide transport through highly compacted bentonite |
| title_fullStr | Modelling key reactive processes relevant to bisulfide transport through highly compacted bentonite |
| title_full_unstemmed | Modelling key reactive processes relevant to bisulfide transport through highly compacted bentonite |
| title_short | Modelling key reactive processes relevant to bisulfide transport through highly compacted bentonite |
| title_sort | modelling key reactive processes relevant to bisulfide transport through highly compacted bentonite |
| topic | Deep geological repository Used nuclear fuels Numerical models Reactive processes Bisulfide transport Sorption |
| url | http://www.sciencedirect.com/science/article/pii/S2590123024017389 |
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