Ion irradiation damage in zirconate and titanate ceramics for Pu disposition

M. W A Stewart, D. Begg, K. Finnie, M. Colella, H. Li, T. I. McLeod, K. L. Smith, Z. Zhang, W. J. Weber, S. Thevuthasan

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

A wasteform must meet several key requirements: (i) aqueous durability as related to a repository environment, the measurement of which must also allow for long-term processes such as radiation damage and annealing; (ii) the compositional flexibility to cope with real waste streams, which are often variable and not well characterised; (iii) the wasteform must be easy to process and the process parameters must be large enough to cope with changes; and, (iv) the waste loading must be high enough to make the wasteform economically viable. In this paper, we discuss the effect of ion irradiation on pyrochlore-rich titanate and defect-fluorite zirconate ceramics designed for plutonium immobilisation. Samples, with Ce as an analogue for Pu, were made via oxide routes and consolidated by cold-pressing and sintering. Ion irradiation damage was carried out with 2 MeV Au2+ ions to a fluence of 5 ions nm-2 in the accelerator facilities within the Environmental Molecular Sciences Laboratory at Pacific Northwest National Laboratory. Irradiated and non-irradiated samples were examined by x-ray diffraction, scanning and transmission electron microscopy, x-ray photoelectron and infra-red spectroscopy, and spectroscopic ellipsometry. Samples underwent accelerated leach testing at pH 1.75 (nitric acid) at 90°C for 28 days. The zirconate samples were more ion-irradiation damage resistant than the titanate samples, showing little change after ion-irradiation whereas the titanate samples formed an amorphous surface layer ∼ 500 nm thick. While all samples had high aqueous durability, the titanate leach rate was ∼ 5 times that of the zirconate. The ion-irradiation increased the leach rate of the titanate without impurities by ∼ 5 times. The difference in the leach rates between irradiated and unirradiated zirconate samples is small. However, the zirconates were less able to incorporate impurities than the titanate ceramics and required higher sintering temperatures, ∼ 1500°C compared to 1350°C for the titanates.

Original languageEnglish
Title of host publicationProceedings of the International Conference on Radioactive Waste Management and Environmental Remediation, ICEM
EditorsG. Benda, F. Sheil
Pages1249-1255
Number of pages7
Volume2
DOIs
Publication statusPublished - 2003
Externally publishedYes
Event9th International Conference on Environmental Remediation and Radioactive Waste Management - Oxford
Duration: 21 Sep 200325 Sep 2003

Other

Other9th International Conference on Environmental Remediation and Radioactive Waste Management
CityOxford
Period21/9/0325/9/03

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ASJC Scopus subject areas

  • Waste Management and Disposal

Cite this

Stewart, M. W. A., Begg, D., Finnie, K., Colella, M., Li, H., McLeod, T. I., Smith, K. L., Zhang, Z., Weber, W. J., & Thevuthasan, S. (2003). Ion irradiation damage in zirconate and titanate ceramics for Pu disposition. In G. Benda, & F. Sheil (Eds.), Proceedings of the International Conference on Radioactive Waste Management and Environmental Remediation, ICEM (Vol. 2, pp. 1249-1255) https://doi.org/10.1115/ICEM2003-4746