Complex fluorite-structured oxides for actinide wastes immobilization
- Igemras, Staromonetny 35, 109017 Moscow (Russian Federation)
- SIA 'Radon', 7-th Rostovsky 2/14, 119121 Moscow (Russian Federation)
Ceramics composed of fluorite-type structure oxides - pyrochlore and murataite, were studied. The samples were produced by melting in air at 1400-1500 deg. C in the system: Ca-Mn-U-REE-Zr-Ti-Al-Fe-O. The phases have nominal formula A{sub 2}B{sub 2}O{sub 7-x} (0<0.5) and A{sub 4}B{sub 2}C{sub 7}O{sub 22}. Sites 'A' in their structures are occupied by Ca, Mn, U, and REEs; 'B' = Ti and Zr; 'C' = Ti, Mn, Al, and Fe. Amounts of these phases varied from 10 to 90 vol.%. The other compounds were perovskite, zirconolite, hibonite, loverengite, rutile, pseudobrookite. Fluorite structure oxides can accommodate large amounts of actinides, rare earths, and contaminants. Uranium enters preferably pyrochlore and murataite as compared to the other actinide-bearing phases. Their lattices incorporate neutron absorber Gd and Hf (geochemical analogue of Zr) prevented the ceramics from auto-criticality. The data suggest ability of pyrochlore-murataite forms to incorporate up to 40 wt% of An-REE fraction of HLW.
- Research Organization:
- American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
- OSTI ID:
- 23142121
- Resource Relation:
- Conference: Global'99: International Conference on Future Nuclear Systems - Nuclear Technology - Bridging the Millennia, Las Vegas, NV (United States), 29 Aug - 3 Sep 1999; Other Information: Country of input: France; 11 refs.; available from American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 (US)
- Country of Publication:
- United States
- Language:
- English
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