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Modelling coupled processes in bentonite: recent results from the UK's contribution to the Äspö EBS Task Force

Published online by Cambridge University Press:  05 July 2018

D. Holton ,
S. Baxter  and
A. R. Hoch
D. Holton*
Affiliation:
AMEC, Building 150, Thomson Avenue, Harwell, Didcot, Oxfordshire OX11 0QB, UK
S. Baxter
Affiliation:
AMEC, Building 150, Thomson Avenue, Harwell, Didcot, Oxfordshire OX11 0QB, UK
A. R. Hoch
Affiliation:
AMEC, Building 150, Thomson Avenue, Harwell, Didcot, Oxfordshire OX11 0QB, UK
*
*E-mail: david.holton@amec.com
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Abstract

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A range of potential concepts for the geological disposal of high level wastes and spent fuel are being studied and considered in the UK. These include concepts that use bentonite as a buffer material around the waste containers. The bentonite will be required to fulfil certain safety functions, the most important being (1) to protect the waste containers from detrimental thermal, hydraulic, mechanical and chemical processes; and (2) to retard the release of radionuclides from any waste container that fails. The bentonite should have a low permeability and a high sorption capacity.

These safety functions could be challenged by certain features, events and processes (FEPs) that may occur during the evolution of the disposal system. A consideration of how these FEPs may affect the safety functions can be used to identify and to prioritize the important areas for research on bentonite. We identify these important areas (which include hydration of compacted bentonite, illitization and erosion of bentonite), and describe how they are being investigated in current international research on bentonite.

The Äspö EBS Task Force is a collaborative international project designed to carry out research on bentonite. In 2011, the Nuclear Decommissioning Authority Radioactive Waste Management Directorate joined the EBS Task Force partly to benefit from its collective experience. The work of the EBS Task Force is split into two research subareas: (1) the THM subarea, which includes tasks to understand homogenization of bentonite as it resaturates, to investigate the hydraulic interaction between bentonite and fractured rock, and to model in situ experiments; and (2) the THC subarea, which includes tasks to investigate the issue of understanding transport through bentonite, and to model in situ experiments. In particular, the bentonite rock interaction experiment is a large-scale in situ experiment concerned with understanding groundwater exchange across bentonite rock interfaces, with the objective of establishing better understanding of bentonite wetting. In this paper, we describe our work to model the spatial and temporal resaturation of bentonite buffer in a fractured host rock.

Keywords

events and processes (FEPS)bentoniteengineered barrier system (EBS)coupled processesthermal (T)hydraulic (H)mechanical (M)chemical (C)resaturationbuffer
Type
Research Article
Information
Mineralogical Magazine , Volume 76 , Issue 8 , December 2012 , pp. 3033 - 3043
Creative Commons
Creative Common License - CCCreative Common License - BY
© [2012] The Mineralogical Society of Great Britain and Ireland. This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY) licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2012

References

Alonso, E.E., Gens, A. and Josa, A. (1990) A constitutive model for partially saturated soils. Géotechnique, 40, 405–430.CrossRefGoogle Scholar
Andra (2005) Dossier 2005 Argile: tome architecture and management of a geological repository. Andra report C.RP.ADP.04.0001. Andra, Chatenay- Malabry, FranceGoogle Scholar
Arcos, D., Grandia, F. and Doménech, C. (2006) Geochemical evolution of the near field of a KBS-3 repository. SKB report SKB TR-06–16. SKB, Stockholm.Google Scholar
Bockgård, N., Vidstrand, P., Å kesson, M., Fransson, Å . and Stigsson, M. (2010) Task 8: Modelling the Interaction between Engineered and Natural Barriers - an Assessment of a Fractured Bedrock Description in the Wetting Process of Bentonite at Deposition Tunnel Scale. SKB report 2010–04.14. SKB, Stockholm.Google Scholar
Cliffe, K.A., Holton, D., Houston, P., Jackson, C., Joyce S. and Milne, A. (2011) Conditioning discrete fracture network models of groundwater flow. International Journal of Numerical Analysis and Modeling, 8, 543–565.Google Scholar
Itasca (2011) FLAC3D. Itasca, Minneapolis, USA.Google Scholar
Jackson, C.P., Hoch A.R. and Todman, S. (2000) Selfconsistency of a heterogeneous continuum porous medium representation of a fractured medium. Water Resources Research, 36, 189–202.CrossRefGoogle Scholar
Karnland, O. and Birgersson, M. (2006) Montmorillonite Stability With Special Respect to KBS-3 Conditions. SKB Technical Report TR-06–11. SKB, Stockholm.Google Scholar
Miller, B. and Marcos, N. (2007) Process Report - FEPs and Scenarios for a Spent Fuel Repository at Olkiluoto. Posiva report 2007–12. POSIVA, Eurajoki, Finland.Google Scholar
Nagra (2002) Project Opalinus Clay Safety Report: Demonstration of disposal feasibility for spent fuel, vitrified high-level waste and long lived intermediate- level waste (Enstorgungsnachweis). Nagra Technical Report 02–05. National Cooperative for the Disposal of Radioactive Waste, Wettingen, Switzerland.Google Scholar
Nuclear Decommissioning Authority (2010a) Geological Disposal: Generic Disposal Facility Designs . NDA/RW MD/048 . Nuclear Decommissioning Authority, Harwell, Didcot, Oxfordshire, UK.Google Scholar
Nuclear Decommissioning Authority (2010b) Geological Disposal: Near-field evolution status report . NDA/R WMD/033 . Nuclear Decommissioning Authority, Harwell, Didcot, Oxfordshire, UK.Google Scholar
Nuclear Decommissioning Authority (2010c) Geological Disposal: Generic Disposal System Technical Specification. NDA/RWMD/044. Nuclear Decommissioning Authority, Harwell, Didcot, Oxfordshire, UK.Google Scholar
Pruess, K., Oldenburg, C. and Moridis, G. (1999) TOUGH2 User’s Guide - Version 2.0. Lawrence Berkeley National Laboratory Report LBNL-43134. Lawrence Berkeley National Laboratory, Berkeley, California, USA.Google Scholar
Pusch, R. (2002) The Buffer and Backfill Handbook Part1: Definitions, Basic Relationships, and Laboratory Methods. SKB Technical Report TR- 02–20. SKB, Stockholm.Google Scholar
Rautioaho, E. and Korkiala-Tanttu, L. (2009) Bentomap: Survey of bentonite and tunnel backfill knowledge: State-of-the-art. VTT Working papers 13. VTT, Finland.Google Scholar
Senna, C., Salas, J. and Arcos, D. (2010) Thermo-hydrogeochemical modelling of the bentonite buffer. SKB Technical Report 10–65. SKB, Stockholm.Google Scholar
Serco (2011) ConnectFlow. Verification Document Release 10.1.1.Google Scholar
SKB (2006) Long-term safety for KBS-3 repositories at Forsmark and Laxemar - a first evaluation. Main Report of the SR-Can project, SKB Technical Report 06–09. SKB, Stockholm.Google Scholar
SKB (2010) Buffer backfill and closure process report for the safety assessment SR-Site. SKB Technical Report 10–47. SKB, Stockholm.Google Scholar
Skoczylas, F. (2010) Experimental results using aluminium-Plexiglass’’ tubes (bentonite/argillite interface): 18 Months report. FORGE Report D3.07, 2010.Google Scholar
Steefel, C., Rutqvist, J., Tsang, C-F., Liu, H-H., Sonnenthal, E., Houseworth, J. and Birkholzer, J. (2010) Reactive Transport and Coupled THM Processes in Engineering Barrier Systems. Lawrence Berkeley National Laboratory Report. Lawrence Berkeley National Laboratory, Berkeley, California, USA.Google Scholar
TILA-99 (1999) Safety assessment of spent fuel in Hästholmen, Kivetty, Olkiluoto and Romuvaara. POSIVA Report 99–07.POSIVA, Eurajoki, Finland.Google Scholar
Wilson, J., Savage, D., Bond, A., Watson, S., Pusch R. and Bennett, D. (2010) Bentonite: A Review of Key Properties, Processes and Issues for Consideration in the UK Context. Qunitessa Report QRS-1378ZG-1, Version 1.0.Google Scholar