Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-26T22:51:16.933Z Has data issue: false hasContentIssue false
  • English
  • Français

Mineralogical investigations of the first package of the alternative buffer material test – II. Exchangeable cation population rearrangement

Published online by Cambridge University Press:  09 July 2018

R. Dohrmann ,
S. Olsson ,
S. Kaufhold  and
P. Sellin
R. Dohrmann*
Affiliation:
Landesamt für Bergbau, Energie und Geologie (LBEG), Stilleweg 2, D-30655 Hannover, Germany Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Stilleweg 2, D-30655 Hannover, Germany
S. Olsson
Affiliation:
Clay Technology AB, IDEON ResearchCenter, SE-22370 Lund, Sweden
S. Kaufhold
Affiliation:
Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Stilleweg 2, D-30655 Hannover, Germany
P. Sellin
Affiliation:
Swedish Nuclear Fuel and Waste Management Co (SKB), Pl 300, SE-57295 Figeholm, Sweden
*
*E-mail: [email protected]
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Bentonites are candidate materials for the encapsulation of radioactive waste. In the ‘Alternative Buffer Material test’ (ABM), compacted ring-shaped blocks of eleven different buffer materials (mainly bentonites) were packed vertically on top of each other with an iron tube as heater in the centre. These buffer materials started with various exchangeable cation populations (ECpopulation). The first ‘ABM package’ was terminated 28 months after installation and the bentonites had been exposed to the maximum temperature (130°C) for about one year. The aim of the present study is first: to describe modification of the cation exchange population, and second to understand the influence of the groundwater on cation exchange at different scales. No significant horizontal variation of any exchangeable cation (EC) was detected between 1 and 7 cm distance from contact with the iron tube. Large total differences of the ECpopulations, however, were observed for the individual blocks after the field experiment (n = 21 blocks) with respect to the composition of the reference materials. The average cation exchange capacity (CEC) values of the analysed bentonites (n = 9 blocks) decreased by 5.5 meq/100 (1.1 – 8.8 meq/100 g) after the experiment. Exchangeable Na+ and Mg2+ decreased on average, whereas Ca2+ increased. This trend was pronounced in the top region of the parcel (upper seven blocks). Although most changes occurred on the large scale of the whole test parcel, small but important changes were also recorded in the vertical direction on the centimetre scale. The observed differences cannot be explained assuming simply that a bentonite reacts only with neighbouring blocks, which would mean that the system was more or less closed. The differences are much larger and the only conclusion from this observation is that the whole package seems to be influenced by the groundwater which was added from a water tank at the experiment site, enabling at least partial equilibration between the different blocks.

Keywords

CECexchangeable cation populationbentonite bufferCu-trien5×calciteethanolic ammonium chloride solutionalteration. URL
Type
Research Article
Information
Clay Minerals , Volume 48 , Issue 2 , May 2013 , pp. 215 - 233
Creative Commons
Creative Common License - CCCreative Common License - BY
Copyright © The Mineralogical Society of Great Britain and Ireland 2013 This is an Open Access article, distributed under the terms of the Creative Commons Attribution license. (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2013

References

Arcos, D., Bruno, J., Benbow, S. & Takase, H. (2000) Behaviour of bentonite accessory minerals during the thermal stage. TR-00-06, Swedish Nuclear Fuel and Waste Management Company (SKB), Stockholm, Sweden, 52 pp. http://www.skb.se/upload/publications/pdf/TR-00-06webb.pdf Google 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
Dixon, D.A., Martino, J.B., Vignal, B., Masumoto, K. & Fujita, T. (2007) Overview of the evolution, performance and state of a bentonite-based tunnel seal after 5 years of operation. Physics and Chemistry of the Earth, 32, 741–752.Google Scholar
Dohrmann, R. (2006) Cation exchange capacity methodology II: proposal for a modified silver-thiourea method. Applied Clay Science, 34, 38–4.10.1016/j.clay.2006.02.009Google Scholar
Dohrmann, R. & Kaufhold, S. (2009) Three new, quick CEC methods for determining the amounts of exchangeable calcium cations in calcareous clays. Clays and Clay Minerals, 57, 338–352.10.1346/CCMN.2009.0570306Google Scholar
Dohrmann, R. & Kaufhold, S. (2010) Determination of exchangeable calcium of calcareous and gypsiferous bentonites. Clays and Clay Minerals, 58, 513–522.10.1346/CCMN.2010.0580108Google Scholar
Dohrmann, R., Genske, D., Karnland, O., Kaufhold, S., Kiviranta, L., Olsson, S., Plötze, M., Sandén, T., Sellin, P., Svensson, D. & Valter, M. (2012a) Interlaboratory exchange of CEC and exchangeable cation results of bentonite buffer material. I. Cu(II)-triethylenetetramine method. Clays and Clay Minerals, 60, 162–175.Google Scholar
Dohrmann, R., Genske, D., Karnland, O., Kaufhold, S., Kiviranta, L., Olsson, S., Plötze, M., Sandén, T., Sellin, P., Svensson, D. & Valter, M. (2012b) Interlaboratory exchange of CEC and exchangeable cation results of bentonite buffer material. II. Alternative methods. Clays and Clay Minerals, 60, 176–185.Google Scholar
Dueck, A., Johannesson, L.-E., Kristensson, O., Olsson, S. & Sjöland, A. (2011) Hydro-mechanical and chemical- mineralogical analyses of the bentonite buffer from a full-scale field experiment simulating a high level waste repository. Clays and Clay Minerals, 59, 595–607.10.1346/CCMN.2011.0590605Google Scholar
Eng, A., Nilsson, U. & Svensson, D. (2007) ä spö Hard Rock Laboratory, Alternative Buffer Material Installation report IPR-07-15, 67 pp., http://skb.se/upload/publications/pdf/ipr-07-15.pdf Google Scholar
Kaufhold, S. & Dohrmann, R. (2003) Beyond the Methylene Blue method: determination of the smectite content using the Cu-trien method. Zeitschrift für Angewandte Geologie, 2, 13–18. ISSN 0044-2259.Google Scholar
Kaufhold, S. & Dohrmann, R. (2008) Detachment of colloids from bentonites in water. Applied Clay Science, 39, 50–59.10.1016/j.clay.2007.04.008Google Scholar
Kaufhold, S. & Dohrmann, R. (2009) Stability of bentonites in salt solutions I sodium chloride. Applied Clay Science, 45, 171–177.10.1016/j.clay.2009.04.011Google Scholar
Kaufhold, S. & Dohrmann, R. (2010a) Stability of bentonites in salt solutions II. Potassium chloride solution – Initial step of illitization? Applied Clay Science, 49, 98–107.10.1016/j.clay.2010.04.009Google Scholar
Kaufhold, S. & Dohrmann, R. (2010b) Effect of extensive drying on the cation exchange capacity of bentonites. Clay Minerals, 45, 441–448.10.1180/claymin.2010.045.4.441Google Scholar
Kaufhold, S. & Dohrmann, R. (2011) Stability of bentonites in salt solutions III Ca-hydroxide solutions. Applied Clay Science, 51, 300–307.10.1016/j.clay.2010.12.004Google Scholar
Kaufhold, S., Dohrmann, R., Koch, D. & Houben, G. (2008) The pH of aqueous bentonite suspensions. Clays and Clay Minerals, 56, 338–343.10.1346/CCMN.2008.0560304Google Scholar
Kaufhold, S., Dohrmann, R., Sandén, T., Sellin, P. & Svensson, D. (2013). Mineralogical investigations of the alternative buffer material test – I. Alteration of bentonites. Clay Minerals, 48, 149–213.10.1180/claymin.2013.048.2.04CrossRefGoogle Scholar
Madsen, F. (1998) Clay mineralogical investigations related to nuclear waste disposal. Clay Minerals, 33, 109–129.10.1180/000985598545318Google Scholar
Meier, L.P. & 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, 386–388.10.1346/CCMN.1999.0470315Google Scholar
Missana, T., Alonso, U., Albarran, N., García-Gutiérrez, M. & Cormenzana, J.-L. (2011) Analysis of colloids erosion from the bentonite barrier of a high level radioactive waste repository and implications in safety assessment. Physics and Chemistry of the Earth, Parts A/B/C, 36, 1607–161.10.1016/j.pce.2011.07.088Google Scholar
Montes-H, G., Fritz, B., Clement, A. & Michau, N. (2005) Modeling of transport and reaction in an engineered barrier for radioactive waste confinement, Applied Clay Science, 29, 155–171.10.1016/j.clay.2005.01.004Google Scholar
Olsson, S. & Karnland, O. (2011) Mineralogical and chemical characteristics of the bentonite in the A2 test parcel of the LOT field experiments at ä spö HRL, Sweden. Physics and Chemistry of the Earth, 36, 1545–1553.Google Scholar
Plötze, M., Kahr, G., Dohrmann, R. & Weber, H. (2007) Hydro-mechanical, geochemical and mineralogical characteristics of the bentonite buffer in a heater experiment. The HE-B project at the Mont Terri rock laboratory. Physics and Chemistry of the Earth, 32, 730–740.Google Scholar
Sanchez, L., Cuevas, J. & Ramirez, S. (2006) Reaction kinetics of FEBEX bentonite in hyper-alkaline conditions resembling the cement-bentonite interface. Applied Clay Science, 33, 125–141.10.1016/j.clay.2006.04.008CrossRefGoogle Scholar
SKB (2007) RD&D Programme 2007. Programme for research, development and demonstration of methods for the management and disposal of nuclear waste. TR-07-12, Swedish Nuclear Fuel and Waste Management Company (SKB), Stockholm, Sweden. http://www.skb.se/upload/publications/pdf/TR-07-12_FUD_2007_eng_webb.pdf Google Scholar
Wersin, P., Johnson, L.H. & McKinley, I.G. (2007) Performance of the bentonite barrier at temperatures beyond 100°C: A critical review. Physics and Chemistry of the Earth, Parts A/B/C, 32, 780–788.10.1016/j.pce.2006.02.051Google Scholar
Yong, R.N. (1999) Editorial. Engineering Geology, 54, 1.10.1016/S0013-7952(99)00054-XGoogle Scholar