Syntheses of titanate-based hosts for the immobilization of Pu(III) and Am(III)
- Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.
Syntheses of novel titanate-based waste forms, potentially suitable for immobilizing Pu(III) and Am(III), have been performed. The dititanate compounds An{sub 2}Ti{sub 2}O{sub 7} (An = Pu or Am) were found to have a monoclinic structure. A series of pyrochlore-type solid solutions between An{sub 2}Ti{sub 2}O{sub 7} and the cubic pyrochlore Ln{sub 2}Ti{sub 2}O{sub 7} (Ln = Gd, Er, or Lu) has been established, and limits of solid solubility for An{sub 2}Ti{sub 2}O{sub 7} were determined. These limits were found to increase as the ionic radius of the lanthanide in the host decreased. Strontium-containing titanate compounds SrAn{sub 2}Ti{sub 4}O{sub 12} were also prepared and were characterized as exhibiting a perovskite-type structure. Such compounds could serve as waste hosts for the immobilization of not only the actinide but also {sup 90}Sr. A 2 month leaching study of Er{sub 1.78}Pu{sub 0.22}Ti{sub 2}O{sub 7} and SrPu{sub 2}Ti{sub 4}O{sub 12} by WIPP A brine was performed. Very low amounts (<1 ppm) of Pu(III) were leached. Although the ionic radius of Np(III) is similar to that of Pu(III) and Am(III), analogous Np compounds could not be prepared in any of the titanate systems investigated.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG05-88ER13865
- OSTI ID:
- 572091
- Report Number(s):
- CONF-961202--
- Country of Publication:
- United States
- Language:
- English
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