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Long term leachate evolution during flow-through leaching of a vault backfill (NRVB)

Published online by Cambridge University Press:  05 July 2018

E. J. Butcher ,
J. Borwick ,
N. Collier  and
S. J. Williams
E. J. Butcher*
Affiliation:
National Nuclear Laboratory (NNL), Sellafield, Seascale, Cumbria CA20 1PG, UK
J. Borwick
Affiliation:
National Nuclear Laboratory (NNL), Sellafield, Seascale, Cumbria CA20 1PG, UK
N. Collier
Affiliation:
National Nuclear Laboratory (NNL), Sellafield, Seascale, Cumbria CA20 1PG, UK
S. J. Williams
Affiliation:
NDA Radioactive Waste Management Directorate (RWMD), Curie Avenue, Harwell, Didcot, Oxfordshire OX11 0RH, UK
*
*E-mail: ed.j.butcher@nnl.co.uk
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Abstract

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Some of the illustrative concepts for the disposal of intermediate-level waste in a geological disposal facility in the UK employ a cementitious backfill around the waste packages. The concept for higher strength rocks would use a highly alkaline backfill composed of Portland cement (now known as CEM I), hydrated lime and limestone flour, referred to as Nirex reference vault backfill (NRVB).

This paper reports a study of the extensive leaching of cured NRVB in a range of generic leachant compositions (deionized water, 0.1 M and 1 M NaCl solutions) under flow-through conditions using a flexible wall permeameter. The experiments were designed to run for up to two years and to pass at least 1000 volumes of leachant (defined as the cumulative leachate volume produced/NRVB solid specimen volume) through the NRVB samples. Results for the pH evolution profiles of the leachates and the microstructural analysis of the unleached and leached samples are presented.

Keywords

buffering capacityleachingNRVBflow-throughgeological disposal facilityrepositorypH evolutionnear field
Type
Research Article
Information
Mineralogical Magazine , Volume 76 , Issue 8 , December 2012 , pp. 3023 - 3031
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

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