Hostname: page-component-848d4c4894-x24gv Total loading time: 0 Render date: 2024-05-18T21:27:34.828Z Has data issue: false hasContentIssue false
  • English
  • Français

Rietveld Analysis of Phase Separation in Annealed and Leach Tested Cm-Doped Perovskite

Published online by Cambridge University Press:  15 February 2011

T. J. White ,
H. Mitamura  and
T. Tsuboi
T. J. White
Affiliation:
Ian Wark Research Institute, The University of South Australia, Warrendi Road, The Levels SA 5095 Australia
H. Mitamura
Affiliation:
Department of Environmental Safety Research, Japan Atomic Energy Research Institute, Tokai-mura, Ibaraki, 319–11Japan.
T. Tsuboi
Affiliation:
Department of Environmental Safety Research, Japan Atomic Energy Research Institute, Tokai-mura, Ibaraki, 319–11Japan.
Get access

Abstract

A quantitative powder X-ray diffraction study was made of actinide doped perovskite of bulk composition Ca0.98919An0.01081Ti0.98919Al0.01081O3 where An corresponded to approximately equimolar proportions of Cm-244 and Pu-240. Sections of this sample accumulated irradiation doses up to 7.51 × 1017 alpha decay events per gram (± g−1). The damaged samples were treated in two ways. First, to establish the critical temperature for structural recovery under the reducing conditions of geological repositories, isochronal annealing was carried out at 600, 800, 1000 and 1100˚C for 12 hours in graphite crucibles. Two groups of perovskites that had previously sustained doses of 4.5 × 1017 and 7.4 × 1017 ± g−1 were tested in this way. For the former group, these conditions resulted in up to 9 weight percent (wt%) of available actinide separating as a fluorite-type dioxide near the perovskite surface. In the latter group, calcium was reduced to the metal which vaporised, leaving an excess of refractory titanium that crystalised as rutile. Second, material which had sustained doses of 1.6–4.0 × 1017 alpha decays per gram was subjected to an MCC-1 leach test for two months at 90˚C using a pH ∼ 2 solution. Under these conditions surficial perovskite dissolved congruently to release calcium into solution while the titanium reprecipitated as anatase. The implications of these results for the ultimate disposal of perovskite-bearing polyphase nuclear waste ceramics are considered.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 353: Symposium – Scientific Basis for Nuclear Waste Management XVIII , 1994 , 871
Copyright
Copyright © Materials Research Society 1995

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. Nesbitt, H.W. et al., Nature, 289, 358 (1981).Google Scholar
2. Myhra, S. et al., Scientific Basis for Nuclear Waste Management XIII, 249 (1990).Google Scholar
3. White, T. & Mitamura, H., Scientific Basis for Nuclear Waste Management XVI, 109 (1993).Google Scholar
4. White, T. & Mitamura, H., Scientific Basis for Nuclear Waste Management XVII, 299 (1994).Google Scholar
5. Mitamura, H. et al., Scientific Basis for Nuclear Waste Management XVIII, in press (1995).Google Scholar
6. Wyckoff, R.W.G., Crystal Structures, Vol. 1, Krieger Publishing Co., Florida, p. 26 (1982).Google Scholar
7. Hill, R.J. & Howard, C.J., Australian Atomic Energy Commission, AAEC/M112 (1986).Google Scholar
8. Wang, L.M. & Ewing, R.C., MRS Bulletin, XVII, 19 (1992).Google Scholar
9. Howard, C.J. & Sabine, T.M., J. Phys., C7, 3453 (1974).Google Scholar
10. Kastrissios, T. et al., J. Am. Ceram. Soc., 70, C-144, (1987).Google Scholar