Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-25T15:53:08.252Z Has data issue: false hasContentIssue false
  • English
  • Français

Characterization of a Cerium-Rich Pyrochlore-Based Ceramic Nuclear Waste Form

Published online by Cambridge University Press:  11 February 2011

R. Gieré ,
S. Segvich  and
E. C. BUCK
R. Gieré
Affiliation:
Earth&Atmospheric Sciences, Purdue University, West Lafayette, IN 47907–2051, USA; [email protected]
S. Segvich
Affiliation:
Earth&Atmospheric Sciences, Purdue University, West Lafayette, IN 47907–2051, USA; [email protected] Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
E. C. BUCK
Affiliation:
Pacific Northwest National Laboratory, P. O. Box 999, Richland, WA 99352, USA
Get access

Abstract

Titanate ceramics have been proposed as candidate materials for immobilizing excess weapons plutonium. This study focuses on the characterization of a titanate-based ceramic through X-ray diffraction (XRD), electron probe microanalysis, and electron energy-loss spectroscopy (EELS). Three distinct phases have been identified, and their volume fraction was determined from element distribution maps using Scionimage-NIH Analysis software. This analysis revealed that the pyrochlore-group phase betafite (A2Ti2O7) forms the matrix of the ceramic and occupies 90.4% of the volume. Uniformly distributed in this matrix are perovskite (A2Ti2O6) and Hf-enriched rutile (TiO2), which account for 6.4 vol% and 3.1 vol%, respectively. The studied ceramic exhibits a very low porosity (0.3 vol%), which is characterized by small (<6 μm), rounded and isolated voids. In the studied ceramic, A-site cations are represented by Ca, rare earth elements, and Hf. The powder XRD pattern of the ceramic allowed refining the unit cell parameters for the cubic betafite, which is characterized by a cell edge of 10.132±0.003Å. The EELS data indicate that Ce is present as both Ce3+ and Ce4+ in betafite, whereas in perovskite, all Ce is trivalent.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 757: Symposium II – Scientific Basis for Nuclear Waste Management XXVI , 2002 , II6.4
Copyright
Copyright © Materials Research Society 2003

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Ringwood, A.E., Kesson, S.E., Ware, N.G., Hibbesron, W., and Major, A., Immobilisation of high level nuclear reactor wastes in Synroc, Nature 278, 219 (1979).Google Scholar
2. Ringwood, A.E., Kesson, S.E., Reeve, K.D., Levins, D.M., and Ramm, E.J., in Radioactive Waste Forms for the Future, edited by Lutze, W. and Ewing, R.C. (North Holland, Amsterdam, 1988), pp. 233–334.Google Scholar
3. Donald, I.W., Metcalfe, B.L., and Taylor, R.N.J., J. Mat. Sci. 32, 5851 (1997).Google Scholar
4. Vance, E. R., Ball, C. J., Day, R. A., Smith, K. L., Blackford, M. G., Begg, B., and Angel, P. J., J. Alloys Comp. 213/214, 406 (1994).Google Scholar
5. Smith, K.L., Lumpkin, G.R., Blackford, M.G., and Colella, M., in Advances in Environmental Materials, Vol. II: Environmentally Preferred Materials (White, T. and Stegemann, J.A., eds), Mat. Res. Soc. Proc (Singapore), p. 301–316 (2001).Google Scholar
6. Hart, K.P., Zhang, Y., Loi, E., Aly, Z., Stewart, M.W.A., Brownscombe, A., Ebbinghouse, B.B., and Bourcier, W.L. Mat. Res. Soc. Symp. Proc. 608, 353 (2000).Google Scholar
7. Buck, E. C., Chamberlain, D. B., and Gieré, R., Mat. Res. Soc. Symp. Proc. 556, 19 (1999).Google Scholar
8. Gieré, R., Hatcher, C., Reusser, E., and Buck, E., Mat. Res. Soc. Symp. Proc. 713, 303 (2002).Google Scholar
9. Roberts, S.K., Bourcier, W.L., and Shaw, H.F., Radiochim. Acta 88, 539 (2000).Google Scholar
10. Zhang, Y., Bourcier, W.L., Day, R.A., Colella, M., Thomas, B., Aly, Z., Jostsons, A., J. Nuclear Materials 289, 254 (2001).Google Scholar
11. Bakel, A. J., Zyryanov, V.N., Mertz, C. J., Buck, E. C., and Chamberlain, D. B., Mat. Res. Soc. Symp. Proc. 556, 181(1999).Google Scholar
12. Zamoryanskaya, M.V., and Burakov, B.E., Mat. Res. Soc. Symp. Proc. 663, 301 (2001).Google Scholar
13. Pareizs, J.M., and Cozzi, A.D., in Environmental Issues and Waste Management Technologies in the Ceramic and Nuclear Industries V, Ceram. Trans. 107, 617 (2000).Google Scholar
14. Stewart, M.W.A., Vance, E.R., Day, R.A., Leung, S., Brownscombe, A., Carter, M.L., and Ebbinghaus, B.B., in Environmental Issues and Waste Management Technologies in the Ceramic and Nuclear Industries V, Ceram. Trans. 107, 617 (2000).Google Scholar
15. Pouchou, J.L. and Pichoir, F., Rech. Aérosp. 1984–3, 167 (1984).Google Scholar
16. Jollet, F., Petit, T., Gota, S., Thromat, N., Gautier-Soyer, M., and Pasturel, A., J. Phys. Condens. Matter 9, 9393 (1997).Google Scholar
17. Yang, J., Tang, B., and Luo, S., Mat. Res. Soc. Symp. Proc. 663, 333 (2001).Google Scholar
18. ICDD, Powder Diffraction File (Release 1998). Newton Square, PA.Google Scholar
19. Ball, C.J., Buykx, W.J., Dickson, F.J., Hawkins, K., Levins, D.M., Smart, R.St.C., Smith, K.L., Stevens, G.T., Watson, K.G., Weedon, D., and White, T.J. J. Am. Ceram. Soc. 72, 404 (1989).Google Scholar
20. Sasaki, S., Prewitt, C.T., and Bass, J.D., Acta Cryst. C48, 1668 (1997).Google Scholar
21. Howard, C.J., Sabine, T.M., and Dickson, F., Acta Cryst. B47, 462 (1997).Google Scholar