1887
Volume 2, Issue 1
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Abstract

There is significant international consensus that the appropriate approach for long-term management of radioactive waste is disposal in an underground geological disposal facility. The gaps between waste containers and the host rock may be filled with bentonite, which swells to fill the gaps as it absorbs groundwater. Bentonite is soft, absorbing shear displacements in the host rock, and has low permeability, which restricts groundwater flow and hence corrosion of the waste containers. Many experiments have studied localized inflows of water into a region of bentonite pellets. Upward flow against gravity has often been observed. This study attempted to build understanding of this by modelling one experiment. A systematic approach was adopted in which models of increasing complexity were used, with the parameters at earlier stages used as a guide for later stages. Initially, only water flow was considered. Then water absorption and swelling, which lead to stresses and strains, were addressed. On the basis of the understanding developed, a conceptual model that represents the observed behaviour is proposed.

This article is part of the Sustainable geological disposal and containment of radioactive waste collection available at: https://www.lyellcollection.org/topic/collections/radioactive

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2024-03-28
2024-04-24
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References

  1. Åberg, A.2009. Effects of Water Inflow on the Buffer – An Experimental Study. Report SKB R-09-29. Svensk Kärnbränslehantering AB (SKB), Solna, Sweden.
    [Google Scholar]
  2. Carter, M. and Bentley, S.1991. Correlations of Soil Properties. Penetech Press, London.
    [Google Scholar]
  3. COMSOL2019a. Subsurface Flow Module User's Guide, Version 5.5. COMSOL AB, Stockholm.
    [Google Scholar]
  4. COMSOL2019b. Structual Mechanics Module User's Guide, Version 5.5. COMSOL AB, Stockholm.
    [Google Scholar]
  5. Dodd, J., Tsitsopoulos, V., Hoch, A., Holton, D. and Åkesson, M.2019. Modelling Water Transport in Bentonite Pellets: Task 10 of the EBS Task Force. Wood Report RWM007340. Wood, Aberdeen, UK.
    [Google Scholar]
  6. Kröhn, K.-P.2004. Modelling the Re-Saturation of Bentonite in Final Repositories in Crystalline Rock. Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) gGmbHmbH, Cologne, Germany.
    [Google Scholar]
  7. Martikainen, J. and Schatz, T.2018. Initial Buffer and Backfill Wetting: Pellet-Filling Component. Working Report WR-2016-53. Posiva Oy, Eurajoki, Finland.
    [Google Scholar]
  8. Martikainen, J., Laurila, T. and Leino, T.2017. Backfill Pellets Wetting Behavior Tests. Report 15890. Saanio and Riekkola Oy, Helsinki, Finland.
    [Google Scholar]
  9. Mohanty, B.P. 2000. Saturated hydraulic conductivity and soil water retention properties across a soil-slope transition. Water Resource Research, 36, 3311–3324, https://doi.org/10.1029/2000WR900216
    [Google Scholar]
  10. Mohanty, B.P., Ankeny, M.D., Horton, R. and Kanwar, R.S. 1994. Spatial analysis of hydraulic conductivity measured using disc infiltrometers. Water Resource Research, 30, 2489–2498, https://doi.org/10.1029/94WR01052
    [Google Scholar]
  11. Morén, L.2010. Design and Production of the KBS-3 Repository. Report SKB TR-10-12. Svensk Kärnbränslehantering AB (SKB), Solna, Sweden.
    [Google Scholar]
  12. RWM2016. Geological Disposal – Design Status Report. NDA Report NDA/RWM/141. Radioactive Waste Management Ltd (RWM), Didcot, UK.
    [Google Scholar]
  13. Sandén, T. and Börgesson, L.2010. Early Effects of Water Inflow into a Deposition Hole. Laboratory Tests Results. Report SKB R-10-70. Svensk Kärnbränslehantering AB (SKB), Solna, Sweden.
    [Google Scholar]
  14. Sandén, T., Börgesson, L., Dueck, A., Goudarzi, R. and Lönnqvist, M.2008. Deep Repository-Engineered Barrier System: Erosion and Sealing Processes in Tunnel Backfill Materials Investigated in Laboratory. Report SKB R-08-135. Svensk Kärnbränslehantering AB (SKB), Solna, Sweden.
    [Google Scholar]
  15. SKB and Posiva Working Group2017. Safety Functions, Performance Targets and Technical Design Requirements for a KBS-3 V Repository. Conclusions and Recommendations from a Joint SKB and Posiva Working Group. Posiva SKB Report 01. Svensk Kärnbränslehantering AB (SKB)/Posiva Oy Olkiluoto, Solna, Sweden Eurajoki, Finland.
    [Google Scholar]
  16. Stankiewicz, A. and Pamin, J. 2006. Gradient-enhanced Cam-Clay model in simulation of strain localization in soil. Foundations of Civil and Environmental Engineering, 7, 293–318.
    [Google Scholar]
  17. Tsitsopoulos, V., Appleyard, P., Mather, J., Rodriguez Corral, J., Williams, T. and Holton, D.2020. Modelling of the Full-Scale in situ System Test (FISST). Report RWM 009412. Jacobs, London.
    [Google Scholar]
  18. van Genuchten, M.T. 1980. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Science Society of America Journal, 44, 892–898, https://doi.org/10.2136/sssaj1980.03615995004400050002x
    [Google Scholar]
  19. Villar, M.V.2004. Thermo-Hydro-Mechanical Characteristics and Processes in the Clay Barrier of a High Level Radioactive Waste Repository. Informes Técnicos CIEMAT Report 1044. Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid.
    [Google Scholar]
  20. Wood, D.M.1991. Soil Behaviour and Critical State Soil Mechanics. Cambridge University Press, Glasgow, UK.
    [Google Scholar]
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