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A Glass-Encapsulated Ceramic Wasteform for the Immobilization of Chloride-Containing ILW: formation of Halite Crystals by Reaction Between the Glass Encapsulant and Ceramic Host

Published online by Cambridge University Press:  21 March 2011

I. W. Donald
Affiliation:
Materials Science Research Division, AWE, Aldermaston, Berkshire, RG7 4PR, UK
B. L. Metcalfe
Affiliation:
Materials Science Research Division, AWE, Aldermaston, Berkshire, RG7 4PR, UK
R. S. Greedharee
Affiliation:
Materials Science Research Division, AWE, Aldermaston, Berkshire, RG7 4PR, UK
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Abstract

We have developed a calcium phosphate ceramic based on the mineral phases chlorapatite, Ca5(PO4)3Cl, and spodiosite, Ca2(PO4)Cl, which, on the basis of evidence from non-active simulant studies, is expected to provide an extremely effective host for immobilizing the chloride constituents resulting from the pyrochemical reprocessing of Pu. The immobilized product is in the form of a free-flowing, non-hygroscopic powder in which the chlorides are chemically combined within the mineral phases. In order to provide a monolithic wasteform suitable for long term storage, the feasibility of encapsulating this product in a compatible glass is being assessed. The final wasteform will be manufactured by a pressureless sintering route with sodium aluminophosphate based glasses currently being developed for this purpose. These glasses are of particular interest due to a combination of useful properties which include good sintering characteristics, together with excellent chemical durability. We have noted, however, that during sintering the Na present in the glass reacts with the chlorapatite and spodiosite phases to form a dispersion of halite crystals within the final wasteform. The formation of free halite within the wasteform is clearly undesirable, but can be minimized by careful control over the processing parameters, in particular the sintering temperature, or by reducing the chloride loading in the wasteform. The implications of these findings are highlighted and discussed.

Type
Research Article
Copyright
Copyright © Materials Research Society 2002

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References

REFERENCES

1. Donald, I. W., Metcalfe, B. L. and Taylor, R. N. J., J. Mater. Sci., 32 (1997), 5851.Google Scholar
2. Day, D. E., Proc. XIX Int. Cong. Glass, Volume 2, Extended Abstracts, Society of Glass Technology (Sheffield), 2001, pp. 443444.Google Scholar
3. Day, D. E., Ray, C. S., Marasinghe, K., Karabulut, M. and Fang, X., “An alternative host matrix based on iron phosphate glasses for the vitrification of specialized nuclear waste forms”, DOE Project ID No. 55110, 1 June 1998.Google Scholar
4. Marasinghe, G. K., Karabulut, M., Ray, C. S., Day, D. E., Shuh, D. K., Arren, P. G., Saboung, M. L., Grimsditch, M. and Haeffner, D., J. Non-Cryst. Solids, 263&264, (2000), 146.Google Scholar
5. Forsberg, C. W., Beahm, E. C. and Rudolph, J. C., Mat. Res. Soc. Symp. Proc. Vol. 465, MRS, 1997, pp. 131137.Google Scholar
6. Ikeda, Y., Takashima, Y., Kobayashi, H. and Igarashi, H., J. Nucl. Sci Technol., 32 (1995), 68.Google Scholar
7. Donze, S., Montagne, L., Palavit, G. and Antonini, G., Phys. Chem. Glasses, 42, (2001), 133.Google Scholar
8. Donze, S., Montagne, L. and Palavit, G., Chem. Mater., 12, (2000), 1921.Google Scholar
9. Donze, S., Montagne, L., Palavit, G., Zeyer, M. and Jager, C., J. Non-Cryst. Solids, 263&264, (2000), 132.Google Scholar
10. Lewis, M. A., Fischer, D. F. and Smith, L. J., J. Amer. Ceram. Soc., 76, (1993), 2826.Google Scholar
11. Morss, L. R., Stanley, M. L., Tatko, C. D. and Ebert, W. L., Mat. Res. Symp. Proc. Vol. 608, MRS, 2000, pp. 733738.Google Scholar
12. Sinkler, W., O'Holleran, T. P., Frank, S. M., Richmann, M. K. and Johnson, S. G., Mat. Res. Symp. Proc. Vol. 608, MRS, 2000, pp. 423429.Google Scholar
13. Moschetti, T. L., Sinkler, W., DiSanto, T., Noy, M. H., Warren, A. R., Cummings, D., Johnson, S. G., Goff, K. M., Bateman, K. J. and Frank, S. M., Mat. Res. Symp. Proc. Vol. 608, MRS, 2000, pp.577582.Google Scholar
14. Donald, I. W., Brenchley, M. E., Greedharee, R. S. and Metcalfe, B. L., Proc. XVIII Int. Cong. Glass, Symposium on Waste Materials Vitrification and Processing, edited by Choudhary, M. K., Huff, N. T. and Drummond, C. H., American Ceramic Soc (Westerville, Ohio), 1998, pp. 16.Google Scholar
15. Donald, I. W., Metcalfe, B. L., Brenchley, M. E. and Greedharee, R. S., Proc. Int. Conf. Ageing Studies and Lifetime Extension of Materials, edited by Mallinson, L. G., Klewer Academic / Plenum Publishing (New York), 2000, pp. 647652.Google Scholar
16. Donald, I. W., Metcalfe, B. L. and Greedharee, R. S., Proc. Int. Symp. on Crystallization in Glasses and Liquids, edited by Holand, W., Schweiger, M. and Rheinberger, V., Glastech. Ber. Glass Sci. Technol., 73C1, (2000), pp. 7481.Google Scholar
17. Donald, I. W., Metcalfe, B. L., Brenchley, M. E. and Greedharee, R. S., Proc. XIX Int. Cong. Glass, Volume 2, Extended Abstracts, Society of Glass Technology (Sheffield), 2001, pp. 575576 Google Scholar
18. Donald, I. W., Metcalfe, B. L. and Greedharee, R. S., Proc. XIX Int. Cong. Glass, Volume 2, Extended Abstracts, Society of Glass Technology (Sheffield), 2001, pp. 6465.Google Scholar