Hostname: page-component-586b7cd67f-t8hqh Total loading time: 0 Render date: 2024-11-25T17:30:29.001Z Has data issue: false hasContentIssue false
  • English
  • Français

Element Partitioning in a Pyrochlore-Based Ceramic Nuclear Waste form

Published online by Cambridge University Press:  21 March 2011

R. Gieré ,
C. Hatcher ,
E. Reusser  and
E. C. Buck
R. Gieré
Affiliation:
Earth & Atmospheric Sciences, Purdue University, West Lafayette, IN 47907-1397, USA;[email protected]
C. Hatcher
Affiliation:
Earth & Atmospheric Sciences, Purdue University, West Lafayette, IN 47907-1397, USA;[email protected]
E. Reusser
Affiliation:
Mineralogy & Petrography, ETH-Zentrum, CH-8092 Zürich, Switzerland
E. C. Buck
Affiliation:
Pacific Northwest National Laboratory, P. O. Box 999, Richland, WA 99352, USA
Get access

Abstract

Pyrochlore-rich ceramics containing additional zirconolite, brannerite and rutile have been developed for immobilizing excess weapons plutonium. This study reports data for a ceramic containing small amounts of Al and Mo in addition to the major oxide components of Ti, U, Ca, Hf, Gd and Ce. Hafnium and Gd are added as neutron absorbers, Al and Mo represent impurities. Quantitative electron microprobe data demonstrate that UO2 is strongly partitioned into brannerite (45 wt%), which is present as euhedral crystals with inclusions of unreacted UO2. Pyrochlore forms the groundmass and has an average UO2 content of 28 wt%. Zirconolite contains only 15 wt% UO2, but is significantly more effective in accommodating Hf and Gd than both brannerite and pyrochlore. Zirconolite incorporates U together with Hf and Ce in one structural site, whereas brannerite and pyrochlore accommodate U with Gd in a site that is distinct from that occupied by Hf. Incorporation of Gd into zirconolite takes place via a coupled substitution involving Al, thus explaining the high Al2O3 contents (3 wt%). Molybdenum was not detected in the major oxides, and it might be present in the accessory rutile. Although the studied waste form was designed to incorporate Pu, the present dataset is also valuable because immobilization of highly fissile U (e.g., U-233) might need to be considered in the future.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 713: Symposium JJ – Scientific Basis for Nuclear Waste Management XXV , 2002 , JJ2.4
Copyright
Copyright © Materials Research Society 2002

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. 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 (1994) 406–409.Google Scholar
2. Bakel, A. J., Zyryanov, V.N., Mertz, C. J., Buck, E. C., and Chamberlain, D. B., Mat. Res. Soc. Symp. Proc. 556 (1999), 181–188.Google Scholar
3. Cotton, F. A. and Wilkinson, G. Advanced Inorganic Chemistry, John Wiley & Sons, New York, 1980, 4th ed., pp.824–827.Google Scholar
4. Buck, E. C., Chamberlain, D. B., and Gieré, R., Mat. Res. Soc. Symp. Proc. 556 (1999), 19–26.Google Scholar
5. Pareizs, J.M., and Cozzi, A.D., in Environmental Issues and Waste Management Technologies in the Ceramic and Nuclear Industries V, Ceramic Transactions 107 (2000), 617–624 Google Scholar
6. 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, Ceramic Transactions 107 (2000), 617–624 Google Scholar
7. Pouchou, J.L. and Pichoir, F. Rech. Aérosp 1984–3 (1984) 167–192.Google Scholar
8. ICDD, Powder Diffraction File (Release 1998). Newton Square, PA. Google Scholar
9. Lumpkin, G. R., Smith, K. L., and Gieré, R., Micron 28 (1997) 57–68.Google Scholar
10. Gieré, R., Williams, C. T., and Lumpkin, G. R., Schweizerische Mineralogische und Petrographische Mitteilungen 78 (1998) 433–459.Google Scholar
11. Yang, J. Zhu, X. Tang, B. Luo, S. in Environmental Issues and Waste Management Technologies in the Ceramic and Nuclear Industries V, Ceramic Transactions 107 (2000), 577–583 Google Scholar
12. Gatehouse, B. M., Grey, I. E., Hill, R. J., Rossell, H. J., Acta Cryst B37 (1981) 306–312.Google Scholar
13. Shannon, R.D., Acta Cryst A32 (1976), 751–767.Google Scholar
14. Fortner, J.A., Kropf, A.J., Bakel, A.J., Hash, M.C., Aase, S.B., Buck, E.C., and Chamberlain, D.B., Mat. Res. Soc. Symp. Proc. 608 (2000), 401–406.Google Scholar
15. Vance, E.R., Watson, J.N., Carter, M.L., Day, R.A., Lumpkin, G.R., Hart, K.P., Zhang, Y. McGlinn, P.J., M.Stewart, W.A., and Cassidy, D.J., in Environmental Issues and Waste Management Technologies in the Ceramic and Nuclear Industries V, Ceramic Transactions 107 (2000), 561–568 Google Scholar