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Chemical durability of vitrified wasteforms: effects of pH and solution composition

Published online by Cambridge University Press:  05 July 2018

C. A. Utton ,
S. W. Swanton ,
J. Schofield ,
R. J. Hand ,
A. Clacher  and
N. C. Hyatt
C. A. Utton
Affiliation:
Immobilisation Science Laboratory, Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK
S. W. Swanton*
Affiliation:
AMEC, B150, Thomson Avenue, Harwell Oxford, Didcot, Oxfordshire OX11 0QB, UK
J. Schofield
Affiliation:
AMEC, B150, Thomson Avenue, Harwell Oxford, Didcot, Oxfordshire OX11 0QB, UK
R. J. Hand
Affiliation:
Immobilisation Science Laboratory, Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK
A. Clacher
Affiliation:
AMEC, B150, Thomson Avenue, Harwell Oxford, Didcot, Oxfordshire OX11 0QB, UK
N. C. Hyatt
Affiliation:
Immobilisation Science Laboratory, Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK
*
*E-mail: steve.swanton@amec.com
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Abstract

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Vitrification is used for the immobilization and conditioning of high-level waste (HLW) arising from the reprocessing of spent nuclear fuel in the UK. Vitrification is also under consideration for the immobilization of certain intermediate-level wastes (ILW), where there may be advantages of volume reduction and removal of uncertainties in long-term waste behaviour, compared to encapsulation in a cement grout. This paper gives an overview of recent work into the chemical durability of UK vitrified wasteforms to inform the technical specification for the disposal facilities for these waste products and the treatment of their long-term behaviour in post-closure performance assessment. This has included: (1) measurements of the initial glass dissolution rates of a simulated HLW Magnox waste glass in a range of groundwater types representative of potential UK host geologies and in simulated high pH near-field porewaters relevant to potential disposal concepts, using Product Consistency Test type-B (PCT-B) at 40°C; and (2) durability testing of three simulant ILW glasses in a saturated calcium hydroxide buffered solution to simulate conditions in cement-based disposal vaults, using PCT-B tests at 50°C.

The experimentally defined initial rate of HLW Magnox waste glass dissolution in a range of simulated groundwater compositions appears to be similar regardless of the ionic strength and major element composition of the solution. The release of caesium from HLW Magnox waste glass appears to be sensitive to solution composition. Caesium is selectively retained in the glass compared to other soluble components in the two low ionic strength solutions, but is released at similar rates to other soluble components in the three groundwaters and Ca(OH)2 solution. Whether this change in caesium retention is an ionic strength effect or is related to changes in the nature of the surface alteration layer formed on the glass, has yet to be established. For HLW Magnox waste glass, dissolution is accelerated at high pH in NaOH solution, however, the presence of calcium acts to mitigate the effects of high pH, at least initially. In Ca(OH)2 solution, calcium is found to react with all the glasses studied leading to the formation of calcium-containing alteration products. The initial dissolution behaviour in Ca(OH)2 solution varies with glass composition and in particular appears to be sensitive to the boron content.

Keywords

high-level waste glassintermediate-level waste glasschemical durability
Type
Research Article
Information
Mineralogical Magazine , Volume 76 , Issue 8 , December 2012 , pp. 2919 - 2930
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

References

Abraitis, P.K., McGrail, B.P., Trivedi, D.P., Livens, F.R. and Vaughan D.J. (2000) Single-pass flow-through experiments on a simulated waste glass in alkaline media at 40ºC. I. Experiments conducted at variable solution flow rate to glass surface area ratio. Journal of Nuclear Materials, 280, 196–205.CrossRefGoogle Scholar
Artinger, R., Buckau, G., Geyer, S., Fritz, P., Wolf, M. and Kim, J.I. (2000) Characterization of groundwater humic substances: influence of sedimentary organic carbon. Applied Geochemistry, 15, 97–116.Google Scholar
ASTM (2008) Standard Test Methods for Determining Chemical Durability of Nuclear, Hazardous, and Mixed Waste Glasses and Multiphase Glass Ceramics: the Product Consistency Test (PCT). C1285-02. American Society for Testing and Materials International, West Conshohocken, Pennsylvania, United States.Google Scholar
Bingham, P.A., Hyatt, N.C., Hand, R.J. and Wilding, C.R. (2009) Glass development for vitrification of wet intermediate level waste (WILW) from decommissioning of the Hinkley Point ‘A’ site. MRS Proceedings, 1124, http://dx.doi.org/10.1557/PROC- 1124-Q03-07.CrossRefGoogle Scholar
Bond, K.A. and Tweed, C. J. (1995) Groundwater Compositions for the Borrowdale Volcanic Group, Boreholes 2, 4 and RCF3, Sellafield, Evaluated using Thermodynamic Modelling. AEA Technology Report NSS/R397.Google Scholar
Curti, E., Crovisier, J.L., Morvan, G. and Karpoff, A.M. (2006) Long-term corrosion of two nuclear waste reference glasses (MW and SON68): a kinetic and mineral alteration study. Applied Geochemistry, 21, 1152–1168.CrossRefGoogle Scholar
Deegan, D., Murray, A., Slaney, B. and Wise, M. (2007) Plasma Vitrification of ILW Sludges. Presented at the UK Decommissioning and Waste Management Conference 16–17.October 2007.Google Scholar
Frugier, P., Chave, T., Gin, S. and Lartigue, J.-E. (2008) Application of the GRAAL model to leaching experiments with SON68 nuclear glass in initially pure water. Journal of Nuclear Materials, 380, 8–21.CrossRefGoogle Scholar
Gaucher, E.C., Blanc, P., Bardot, F., Braibant, G., Buschaert, S., Crouzet, C., Gautier, A., Girard, J-P., Jacquot, E., Lassin, A., Negrel, G., Tournassat, C., Vinsot, A. and Altmann, S. (2006) Modelling the porewater chemistry of the Callovian-Oxfordian formation at the regional scale. Compte Rendus Geoscience, 338, 917–930.CrossRefGoogle Scholar
Gin, S. and Jégou, C. (2001) Limiting mechanisms of borosilicate glass alteration kinetics: effect of glass composition. Pp. 279–282.in: Water-Rock Interaction (RCidu, editor). A.A Balkema, Rotterdam, The Netherlands.Google Scholar
Marivoet, J., Volckaert, G., Labat, S., De Canniére, P., Dierckx, A., Kursten, B., Lemmens, K., Lolivier, P., Mallants, D., Sneyers, A., Valcke, E., Wang, L. and Wemaere, I. (1999) Values for the Near Field Clay Parameters Used in the Performance Assessment of the Geological Disposal of Radioactive Waste in the Boom Clay Formation at the Mol Site, Volumes 1 and 2. SCK CEN Report R-3344.Google Scholar
Nuclear Decommissioning Authority (2010) Geological Disposal: Generic Post-closure Safety Assessment. NDA Report NDA/RWMD/030.Google Scholar
Nuclear Decommissioning Authority and Department of Energy and Climate Change (2011) The 2010 UK Radioactive Waste Inventory. Main Report. Report URN 10D/985, NDA/ST/STY(11)0004.Google Scholar
Press, W.H., Flannery, B.P., Teukolsky S.A. and Vetterling, W. T. (1986) Numerical Recipes - The Art of Scientific Computing. Cambridge University Press, Cambridge.Google Scholar
Scales, C.R. (2011) Characterisation of Simulated Vitrified Magnox Product Manufactured on the VTR. National Nuclear Laboratory Report NNL(10) 10929 Issue 6.Google Scholar
Schofield, J., Clacher, A., Utton, C.A., Swanton, S.W. and Hand, R.J. (2012) Initial Dissolution Rate Measurements for Simulant 25 wt% Waste-loaded Magnox VTR Product in Simulant Water Types. Serco Report Serco/004844/02, Issue 2.Google Scholar
Utton, C.A., Hand, R.J. , Hyatt, N.C. and Swanton, S.W. (2012) Interaction of Vitrified Wastes with NRVB. Serco Report Serco/TAS/ 003133/002 Issue 2.Google Scholar
Zwicky, H.U., Grambow, B., Magrabi, C., Aerne, E.T., Bradley, R., Barnes, B., Graber, Th., Mohos, M. and Werme, L.C. (1989) Corrosion behaviour of British Magnox waste glass in pure water. MRS Proceedings, 127, http://dx.doi.org/10.1557/PROC- 127–129. The AEA Technology, NDA, NNL and Serco Reports listed above are available from the NDA bibliography.CrossRefGoogle Scholar