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Preparation and Characterization of a Calcium Phosphate Ceramic for the Immobilization of Chloride-containing Intermediate Level Waste

Published online by Cambridge University Press:  11 February 2011

Brian L. Metcalfe ,
Ian W. Donald ,
Randy D. Scheele  and
Denis M. Strachan
Brian L. Metcalfe
Affiliation:
Atomic Weapons Establishment, Aldermaston, Berkshire, UK
Ian W. Donald
Affiliation:
Atomic Weapons Establishment, Aldermaston, Berkshire, UK
Randy D. Scheele
Affiliation:
Atomic Weapons Establishment, Aldermaston, Berkshire, UK
Denis M. Strachan
Affiliation:
Atomic Weapons Establishment, Aldermaston, Berkshire, UK
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Abstract

Attention has recently been given to the immobilization of special categories of radioactive wastes, some of which contain high concentrations of actinide chlorides. Although vitrification in phosphate glass has been proposed, this was rejected because of the high losses of chloride through the mobilization of volatile species.

On the basis of non-radioactive and, more recently, radioactive studies, we have shown that calcium phosphate is an effective host for immobilizing the chloride constituents [1]. In this instance, the chlorine is retained as chloride, rather than evolved as a chlorine-bearing gas. The immobilized product is in the form of a free-flowing, non-hygroscopic powder, in which the chlorides are chemically combined within the synthetic mineral phases chlorapatite [Ca5(PO4)3Cl] and spodiosite [Ca2(PO4)Cl]. Data from studies on non-radioactive simulated waste consisting of a mixture of CaCl2 and SmCl3, and radioactive simulated waste composed of CaCl2 with PuCl3 or PuCl3 and AmCl3, are presented and compared.

The XRD data confirm the presence of chlorapatite and spodiosite in the non-radioactive and radioactive materials. The durability of all specimens was measured with a modified MCC-1 test. Normalized releases of Cl after 28 days were 1.6 × 10-3 g m-2 for the non-radioactive specimens and 7 × 10-3 g m-2 for the Pu bearing specimens. Releases of Ca after 28 days were 0.3 × 10-3 and 2.0 × 10-3 g m-2 for the non-radioactive composition and the Pu composition, respectively, whilst release of Pu from the radioactive specimens was higher for the mixed Pu/Am specimen at 1.2 × 10-5g m-2 than for the Pu only specimens. The release of Am from the mixed Pu/Am composition was exceptionally low at 2.4 × 10-7 g m-2. Overall, the release rate data suggest that the ceramics dissolve congruently, followed by precipitation of Sm, Pu and Am as less soluble phases, possibly oxides or phosphates. The differences in behaviour noted between non-radioactive and radioactive specimens are interpreted in terms of the crystal chemistry of the individual systems.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 757: Symposium II – Scientific Basis for Nuclear Waste Management XXVI , 2002 , II6.6
Copyright
Copyright © Materials Research Society 2003

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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. 443–444.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. 131–137.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. 733–738.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. 423–429.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.577–582.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. 1–6.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. 647–652.Google Scholar
16. 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. 575–576.Google Scholar
17. Donald, I. W., Metcalfe, B. L. and Greedharee, R. S., Mat. Res. Symp. Proc. Vol. 713, MRS, 2002, pp.287–293 Google Scholar
18. Donald, I. W., Metcalfe, B. L., Scheele, R. D. and Strachan, D. M., Proc. 10th. Int. Ceramics Congr., 2002, in the press.Google Scholar
19. Senamaud, N., Bernache-Assolant, D., Carpena, J. and Pin, C.,, Mat. Res. Symp. Proc. Vol. 556, MRS, 1999, pp.93–98.Google Scholar
20. Campayo, L., Audubert, F., Lartigue, J. E. and Bernache-Assolant, D., Proc. 10th. Int. Ceramics Congr., 2002, in the press.Google Scholar
21. Kanazawa, T., editor, Inorganic Phosphate Materials, Materials Science Monograph 52, Kodancha (Tokyo), and Elsevier (Amsterdam), 1989, pp. 55–77.Google Scholar
22. Morton, R. D., Norsk Geologisk Tidsskrift, 41, (1961), 223.Google Scholar
23. Narasaraju, T. S. B., Rai, U. S. and Rao, K. K., Indian Journal of Chemistry, 16A, (1978), 952.Google Scholar