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Influence of Transition Metal Charge Compensation Species on Phase Assemblage in Zirconolite Ceramics for Pu Immobilisation

Published online by Cambridge University Press:  07 February 2020

L.R. Blackburn
Affiliation:
Immobilisation Science Laboratory, University of Sheffield, Department of Materials Science and Engineering, Sir Robert Hadfield Building, Mappin Street, S13JD, UK
S.K. Sun
Affiliation:
Immobilisation Science Laboratory, University of Sheffield, Department of Materials Science and Engineering, Sir Robert Hadfield Building, Mappin Street, S13JD, UK
L.J. Gardner
Affiliation:
Immobilisation Science Laboratory, University of Sheffield, Department of Materials Science and Engineering, Sir Robert Hadfield Building, Mappin Street, S13JD, UK
E.R. Maddrell
Affiliation:
National Nuclear Laboratory, Workington, Cumbria, CA14 3YQ, UK
M.C. Stennett
Affiliation:
Immobilisation Science Laboratory, University of Sheffield, Department of Materials Science and Engineering, Sir Robert Hadfield Building, Mappin Street, S13JD, UK
N.C. Hyatt*
Affiliation:
Immobilisation Science Laboratory, University of Sheffield, Department of Materials Science and Engineering, Sir Robert Hadfield Building, Mappin Street, S13JD, UK
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Abstract

Immobilisation of Pu in a zirconolite matrix (CaZrTi2O7) is a viable pathway to disposition. A-site substitution, in which Pu4+ is accommodated into the Ca2+ site in zirconolite, coupled with sufficient trivalent M3+/Ti4+ substitution (where M3+ = Fe, Al, Cr), has been systematically evaluated using Ce4+ as a structural analogue for Pu4+. A broadly similar phase assemblage of zirconolite-2M and minor perovskite was observed when targeting low levels of Ce incorporation. As the targeted Ce fraction was elevated, secondary phase formation was influenced by choice of M3+ species. Co-incorporation of Ce/Fe resulted in the stabilisation of a minor Ce-containing perovskite phase at high wasteloading, whereas considerable phase segregation was observed for Cr3+ incorporation. The most favourable substitution approach appeared to be achieved with the use of Al3+, as no perovskite or free CeO2 was observed. However, high temperature treatments of Al containing specimens resulted in the formation of a secondary Ce-containing hibonite phase.

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Articles
Copyright
Copyright © Materials Research Society 2020

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References

Nuclear Decommissioning Authority, NDA Plutonium Options (2008).Google Scholar
Hyatt, N.C., Energy Policy 101, 303 (2017).10.1016/j.enpol.2016.08.033CrossRefGoogle Scholar
Nuclear Decommissioning Authority, NDA Plutonium Topic Strategy: Credible Options Technical Summary (2009).Google Scholar
Stennett, M.C., Hyatt, N.C., Gilbert, M., Livens, F.R., and Maddrell, E.R., in Mater. Res. Soc. Symp. Proc. (2008), pp. 16.Google Scholar
Coelho, A.A., Cheary, R.W., and Smith, K.L., J. Solid State Chem. 129, 346 (1997).10.1006/jssc.1996.7263CrossRefGoogle Scholar
Gatehouse, B.M., Grey, I.E., Hill, R.J., and Rossell, H.J., Acta Cryst. B37, 306 (1981).10.1107/S0567740881002914CrossRefGoogle Scholar
Clark, B.M., Sundaram, S.K., and Misture, S.T., Sci. Rep. 7, 2 (2017).Google Scholar
Ma, S., Ji, S., Liao, C., Liu, C., Shih, K., and He, W., Ceram. Int. 44, 15124 (2018).10.1016/j.ceramint.2018.05.149CrossRefGoogle Scholar
Zubkova, N. V., Chukanov, N. V., Pekov, I. V., Ternes, B., Schüller, W., Ksenofontov, D.A., and Pushcharovsky, D.Y., Zeitschrift Fur Krist. - Cryst. Mater. 233, 463 (2018).10.1515/zkri-2017-2133CrossRefGoogle Scholar
Smith, K.L., Lumpkin, G.R., Blackford, M.G., Day, R.A., and Hart, K.P., J. Nucl. Mater. 190, 287 (1992).10.1016/0022-3115(92)90092-YCrossRefGoogle Scholar
Myhra, S., Bishop, H.E., Rivière, J.C., and Stephenson, M., J. Mater. Sci. 22, 3217 (1987).10.1007/BF01161185CrossRefGoogle Scholar
Li, J., Medina, E.A., Stalick, J.K., Sleight, A.W., and Subramanian, M.A., Prog. Solid State Chem. 44, 107 (2016).10.1016/j.progsolidstchem.2016.11.001CrossRefGoogle Scholar