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Use of bentonite for isolation of radioactive waste products

Published online by Cambridge University Press:  09 July 2018

R. Pusch
R. Pusch*
Affiliation:
Clay Technology AB and Lund University of Technology, Lund, Sweden
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Abstract

Sodium smectite clay, commercially available in the form of bentonite powder, serves as a very effective water flow barrier and cation exchanger. At bulk densities between 1·9 and 2·2 g/cm3 after water uptake to reach complete saturation, the hydraulic conductivity is of the order of 10−14 to 10−13 m/s. The swelling potential produces a tight contact with confining structures, which makes bentonite ideal as overpack of rock-deposited radioactive canisters and for borehole and shaft sealing. At bulk densities between 1·1 and 1·3 g/cm3, the hydraulic conductivity of smectite gels is still sufficiently low to make them useful as effective grouts for sealing rock fractures. The longevity in a granite environment is very significant and the ultimate transformation residue—hydrous mica (“illite”)—preserves some of the excellent sealing properties of smectites.

Type
Research Article
Information
Clay Minerals , Volume 27 , Issue 3 , September 1992 , pp. 353 - 361
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1992

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