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A model for Redox Control in A Cementitious Repository

Published online by Cambridge University Press:  10 February 2011

T. G. Heath  and
C. J. Tweed
T. G. Heath
Affiliation:
AEA Technology plc, Harwell, Didcot, Oxfordshire, OX11 ORA, UK, cherry.tweed@aeat.co.uk
C. J. Tweed
Affiliation:
AEA Technology plc, Harwell, Didcot, Oxfordshire, OX11 ORA, UK, cherry.tweed@aeat.co.uk
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Abstract

Calculations have been performed to investigate long timescale redox control in a cementitious deep waste repository, once there has been significant corrosion of the steel containers in the near field. The methodology considers reaction of the porewater with redoxsensitive solids. The solids were selected based on considerations of the repository concept, the waste inventory and the processing of the waste into a form suitable for disposal. A number of factors that may affect the redox potential have been considered. Amongst these are the form of the redox-controlling solids, the effect of changes in pH, the effect of sorption onto the cementitious backfill, and the effect of the association of dissolved radionuclides with complexants arising from the degradation of organic wastes. The calculations suggest that for the United Kingdom Nirex Limited (Nirex) disposal concept and inventory, the redox system in the near field of the repository would be controlled by the iron(II)/iron(III) redox couple. This would maintain the redox potential in the repository near field at a low value for timescales in excess of 1 million years.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 556: Symposium QQ – Scientific Basis for Nuclear Waste Management XXII , 1999 , 1245
Copyright
Copyright © Materials Research Society 1999

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References

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