Hostname: page-component-586b7cd67f-2brh9 Total loading time: 0 Render date: 2024-11-26T21:35:19.376Z Has data issue: false hasContentIssue false
  • English
  • Français

Electron Microprobe Investigation of Ti-pyrochlore Doped with Pu-238

Published online by Cambridge University Press:  17 March 2011

Maria V. Zamoryanskaya  and
Boris E. Burakov
Maria V. Zamoryanskaya
Affiliation:
Laboratory of Applied Mineralogy and Radiogeochemistry, the V.G. Khlopin Radium Institute, 28, 2-nd Murinskiy ave., St. Petersburg, 194021, Russia, e-mail:, [email protected]
Boris E. Burakov
Affiliation:
Laboratory of Applied Mineralogy and Radiogeochemistry, the V.G. Khlopin Radium Institute, 28, 2-nd Murinskiy ave., St. Petersburg, 194021, Russia, [email protected]
Get access

Abstract

polycrystalline sample of Ti-pyrochlore, (Ca,Gd,Hf,U,Pu)2Ti2O7, doped with approximately 8.7 wt.% 238Pu and 20.0 wt.% 238U, has been studied at different cumulative doses of alpha induced radiation damage using scanning electron microscopy (SEM) and quantitative electron probe microanalysis (EMPA). All analyses of 238Pu-doped Ti-pyrochlore were done for comparison with 239Pu-doped pyrochlore synthesized under similar conditions. Our results suggest that accelerated alpha-induced radiation damage affects not only the crystalline structure of 238Pu-doped pyrochlore, but also causes changes in the chemical composition of the pyrochlore, and as proposed, destruction of pyrochlore-U-Pu solid solution. Numerous inclusions of a separate U-oxide phase were found in the 238Pu-doped pyrochlore crystalline matrix. The inclusions were observed visually using SEM and increased as a function of the cumulative dose. Also, after a cumulative dose of 1.1 × 1025 alpha decays/m3 the pyrochlore became nearly amorphous and inclusions of Hf-Ti-Ca-O phase were found in the crystalline matrix. In all cases separate phases of U-oxide and Hf-Ti-Ca-O were localized in chemically inhomogeneous areas. The results obtained allow us to assume that under self-irradiation the amorphization of Ti-pyrochlore might be accompanied with destruction of single solid solution, (Ca,Gd,Hf,U,Pu)2Ti2O7, into several pyrochlore phases of different chemical composition and precipitation of some amount of Pu and U into separate oxide phases.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 824: Symposium CC – Scientific Basis for Nuclear Waste Management XXVIII , 2004 , CC4.3
Copyright
Copyright © Materials Research Society 2004

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

1. Ebbinghaus, B., VanKonynenburg, R., Ryerson, F. et al., Proc. Int. Symp. WASTE MANAGEMENT'98, Tucson, AZ, USA, 1998, CD-ROM, Rep. 65-04 (1998).Google Scholar
2. Burakov, B., “KRI studies of the U.S. Pu ceramics (B506203),” in Excess Weapons Plutonium Immobilization in Russia, eds. Jardine, L.J., Borisov, G.B., Proc. Meet. for Coordination and Review of Work, St. Petersburg, Russia, Nov. 1-4, 1999, UCRL-ID-138361, 251 (2000).Google Scholar
3. Volkov, Yu., Lukinykh, A., et al., “The effect of 238Pu alfa-decay on the crystalline structure”, in Immobilization of Excess Weapons Plutonium in Russia: A Review of LLNL Contract Work, eds. Jardine, L.J., Borisov, G.B., Proc. Meet. for Coordination and Review of Work, St. Petersburg, Russia, Nov. 13-16, 2000, UCRL-ID-143846, 207 (2001).Google Scholar
4. Burakov, B., Anderson, E., “KRI radiation damage studies of the U.S. Pu ceramics (B506203),” in Immobilization of Excess Weapons Plutonium in Russia: A Review of LLNL Contract Work, eds. Jardine, L.J., Borisov, G.B., Proc. Meet. for Coordination and Review of Work, St. Petersburg, Russia, Nov. 13-16, 2000, UCRL-ID-143846, 229 (2001).Google Scholar