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Hydro-Mechanical and Chemical-Mineralogical Analyses of the Bentonite Buffer from A Full-Scale Field Experiment Simulating a High-Level Waste Repository

Published online by Cambridge University Press:  01 January 2024

Ann Dueck ,
Lars-Erik Johannesson ,
Ola Kristensson ,
Siv Olsson  and
Anders Sjöland
Ann Dueck
Affiliation:
Clay Technology AB, Ideon Science Park, SE-223 70 Lund, Sweden
Lars-Erik Johannesson
Affiliation:
Clay Technology AB, Ideon Science Park, SE-223 70 Lund, Sweden
Ola Kristensson*
Affiliation:
Clay Technology AB, Ideon Science Park, SE-223 70 Lund, Sweden
Siv Olsson
Affiliation:
Clay Technology AB, Ideon Science Park, SE-223 70 Lund, Sweden
Anders Sjöland
Affiliation:
Swedish Nuclear Fuel and Waste Management Co., Box 250, SE-10124 Stockholm, Sweden
*
* E-mail address of corresponding author: [email protected]
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Abstract

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The effect of exposure to repository-like conditions on compacted Wyoming bentonite was determined by comparing the hydraulic, mechanical, and mineralogical properties of samples from the bentonite buffer of the Canister Retrieval Test (CRT) with those of reference material. The CRT, located at the Swedish Äspö Hard Rock Laboratory (HRL), was a full-scale field experiment simulating conditions relevant for the Swedish, so called KBS-3, concept for disposal of high-level radioactive waste in crystalline host rock. The compacted bentonite, surrounding a copper canister equipped with heaters, had been subjected to heating at temperatures up to 95°C and hydration by natural Na-Ca-Cl type groundwater for almost 5 y at the time of retrieval.

Under the thermal and hydration gradients that prevailed during the test, sulfate in the bentonite was redistributed and accumulated as anhydrite close to the canister. The major change in the exchangeable cation pool was a loss in Mg in the outer parts of the blocks, suggesting replacement of Mg mainly by Ca along with the hydration with groundwater. Close to the Cu canister, small amounts of Cu were incorporated into the bentonite. A reduction of strain at failure was observed in the innermost part of the bentonite buffer, but no influence was noted on the shear strength. No change in swelling pressure was observed, while a modest decrease in hydraulic conductivity was found for the samples with the highest densities. No coupling was found between these changes in the hydro-mechanical properties and the montmorillonite — the X-ray diffraction characteristics, the cation exchange properties, and the average crystal chemistry of the Na-converted <1 μm fractions provided no evidence of any chemical/structural changes in the montmorillonite after the 5 y hydrothermal test.

Keywords

BentoniteField ExperimentHydraulic ConductivityHydrothermalMontmorilloniteHigh-level WasteRepositorySwelling PressureUnconfined Compression
Type
Article
Information
Clays and Clay Minerals , Volume 59 , Issue 6 , December 2011 , pp. 595 - 607
Copyright
Copyright © Clay Minerals Society 2011

References

Ammann, L. Bergaya, F. and Lagaly, G., 2005 Determination of the cation exchange capacity of clays with copper complexes revisited Clay Minerals 40 441–453.CrossRefGoogle Scholar
Belyayeva, N.I., 1967 Rapid method for the simultaneous determination of the exchange capacity and content of exchangeable cations in solonetzic soils Soviet Soil Science 1409–1413.Google Scholar
Birgersson, M. and Karnland, O., 2009 Ion equilibrium between montmorillonite interlayer space and an external solution — consequences for diffusional transport Geochimica et Cosmochimica Acta 73 1908–1923.CrossRefGoogle Scholar
Börgesson, L. Johannesson, L.-E. Sandán, T. and Hernelind, J., 1995 Modelling of the physical behaviour of water saturated clay barriers Laboratory tests, material models and finite element application, SKB Technical Report TR-95-20.Google Scholar
Börgesson, L. Johannesson, L.-E. and Hernelind, J., 2004 Earthquake induced rock shear through a deposition hole Effect on the canister and the buffer. SKB Technical Report TR-04-02.CrossRefGoogle Scholar
Dixon, D.A. Graham, J. and Gray, M.N., 1999 Hydraulic conductivity of clays in confined tests under low hydraulic gradients Canadian Geotechnical Journal 36 815–827.CrossRefGoogle Scholar
Dixon, D. Chandler, N. Graham, J. and Gray, M.N., 2002 Two large-scale sealing tests conducted at Atomic Energy of Canada’s underground research laboratory: the buffercontainer experiment and the isothermal test Canadian Geotechnical Journal 39 503–518.CrossRefGoogle Scholar
Dohrmann, R. and Kaufhold, S., 2010 Determination of exchangeable calcium of calcareous and gypsiferous bentonites Clays and Clay Minerals 58 79–88.CrossRefGoogle Scholar
Dueck, A., 2010 Thermo-mechanical cementation effects in bentonite investigated by unconfined compression tests SKB Technical Report TR-10-41.Google Scholar
Dueck, A. Börgesson, L. and Johannesson, L.-E., 2010 Stress strain relation of bentonite at undrained shear Laboratory tests to investigate the influence of material composition and test technique. SKB Technical Report TR-10-32.Google Scholar
Eng, A., 2008 Canister Retrieval Test, Retrieval phase, Project report, SKB International Progress Report IPR-08-13.Google Scholar
ENRESA (2006) FEBEX Full-scale Engineered Barriers Experiment, Updated Final Report 1994–2004. Publicación TécnicaE NRESA 05-0/2006, Madrid.Google Scholar
Fernández, A.M. and Villar, M.V., 2010 Geochemical behaviour of a bentonite barrier in the laboratory after up to 8 years of heating and hydration Applied Geochemistry 25 809–824.CrossRefGoogle Scholar
Gens, A. Sánchez, M. Guimarães, L. Do, N. Alonso, E.E. Lloret, A. Olivella, S. Villar, M.V. and Huertas, F., 2009 A full-scale in situ heating test for high-level nuclear waste disposal: observations, analysis and interpretation Géotechnique 59 377–399.CrossRefGoogle Scholar
Gómez-Espina, R. and Villar, M.V., 2010 Geochemical and mineralogical changes in compacted MX-80 bentonite submitted to heat and water gradients Applied Clay Science 47 400–408.CrossRefGoogle Scholar
Goudarzi, R. and Börgesson, L., 2006 Canister Retrieval Test, Sensors data report (Period 001026-060501) Report No: 12, SKB International Progress Report IPR-06-35.Google Scholar
Huang, W.-L. Longo, J.M. and Pevear, D.R., 1993 An experimentally derived kinetic model for smectite-to-illite conversion and its use as a geothermometer Clays and Clay Minerals 41 162–177.CrossRefGoogle Scholar
Jackson, M.L., 1975 Soil Chemical Analysis — Advanced Course 2nd edition Wisconsin, USA Madison.Google Scholar
Johannesson, L.-E., 2007 Canister Retrieval Test, Dismantling and sampling of the buffer and determination of density and water ratio, SKB International Progress Report IPR-07-16.Google Scholar
Karnland, O. Sandnén, T. Johannesson, L.-E. Eriksen, T.E. Jansson, M. Wold, S. Pedersen, K. Motamedi, M. and Rosborg, B., 2000 Long term test of buffer material Final report on the pilot parcels. SKB Technical Report TR-00-22.Google Scholar
Karnland, O. and Birgersson, M., 2006 Montmorillonite stability — with special respect to KBS-3 conditions, SKB Technical Report TR-06-11.Google Scholar
Karnland, O. Olsson, S. and Nilsson, U., 2006 Mineralogy and sealing properties of various bentonites and smectiterich clay materials SKB Technical Report TR-06-30.Google Scholar
Karnland, O. Nilsson, U. Weber, H. and Wersin, P., 2008 Sealing ability of Wyoming bentonite pellets foreseen as buffer material — laboratory results Physics and Chemistry of the Earth 33 472–475.CrossRefGoogle Scholar
Karnland, O. Olsson, S. Dueck, A. Birgersson, M. Nilsson, U. Hernan-Håkansson, T. Pedersen, K. Nilsson, S. Eriksen, T. and Rosborg, B., 2009 Long term test of buffer material at the Äspä Hard Rock Laboratory, LOT project Final report on the A2 test parcel. SKB Technical Report TR-09-29.Google Scholar
Meier, L.P. and Kahr, G., 1999 Determination of the cation exchange capacity (CEC) of clay minerals using the complexes of copper(II) ion with triethylenetetramine and tetraethylenepentamine Clays and Clay Minerals 47 386–388.CrossRefGoogle Scholar
Kaufhold, S. and Dohrmann, R., 2007 Implications from the LOT experiment regarding the selection of an optimum HLRW bentonite Clays in Natural and Engineered Barriers for Radioactive Waste Confinement. 3rd International Meeting September 2007, Lille, France, Abstracts 85–86.Google Scholar
Plötze, M. Kahr, G. Dohrmann, R. and Weber, H., 2007 Hydro-mechanical, geochemical and mineralogical characteristics of the bentonite buffer in ahea ter experiment: The HE-B project at the Mont Terri Rock Laboratory Physics and Chemistry of the Earth 32 730–740.CrossRefGoogle 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 TR-06-09.Google Scholar
Villar, M.V. and Lloret, A., 2007 Dismantling of the first section of the FEBEX in situ test: THM laboratory tests on the bentonite blocks retrieved Physics and Chemistry of the Earth 32 716–729.CrossRefGoogle Scholar