Inductive cold crucible melting and characterization of uranium and thorium bearing murataite ceramics
- SIA Radon, 7th Rostovskii lane, 2/14, Moscow 19121 (Russian Federation)
- IGEM RAS, Staromonetnii lane 35, Moscow 119117 (Russian Federation)
Murataite-based ceramics containing 10 wt.% either UO{sub 2} or ThO{sub 2} were produced by inductive cold crucible melting (ICCM) at operating frequencies of 1.76 MHz and 5.28 MHz and examined using X-ray diffraction and scanning and transmission electron microscopy. High specific productivity was achieved. Average melting ratio was 8.3 kWh/kg. We identified three distinct murataite polytypes in the U-bearing ceramics: a five- (5C), eight- (8C), and three-fold (3C) fluorite unit cell composing respectively the core, intermediate and rim zones of the grains. In contrast, in the Th-bearing ceramic one of the polytypes with eight-fold (8C) fluorite unit cell was found to be prevailing over two others (5C and 3C). Computer simulation of the major reflection due to the murataite phase in the Th-bearing sample also exhibits superposition of peaks due to three distinct polytypes but one of them (8C) is predominant. The core zone of the murataite in the U-bearing specimens is characterized by UO{sub 2} concentrations as high as 12.1 wt%, which successively diminishes in concentration through the intermediate zone to the rim, the latter of which contains 5.2 wt% UO{sub 2}. Thorium distribution within the murataite crystals is more uniform. The other phases found in the ceramics are crichtonite, rutile and traces of perovskite, Fe/Mn titanate ilmenite/pyrophanite, zirconolite, and vitreous phase. The difference in phase composition and actinide partitioning in the ceramics is influenced by synthesis conditions. Thus, application of large-scale cold crucibles is a prospective route for the development of industrial-scale process and technology for ceramization of actinide-bearing HLW. The advantage of this method is production of zoned crystals with the highest concentrations of actinides and rare earth elements in the core, effectively isolating these elements from potential leach solutions. (authors)
- Research Organization:
- American Society of Mechanical Engineers (ASME), Three Park Avenue, New York, NY 10016-5990 (United States); Technological Institute of the Royal Flemish Society of Engineers (TI-K VIV), Het Ingenieurshuis, Desguinlei 214, 2018 Antwerp (Belgium); Belgian Nuclear Society (BNS) - ASBL-VZW, c/o SCK-CEN, Avenue Hermann Debrouxlaan, 40 - B-1160 Brussels (Belgium)
- OSTI ID:
- 21156326
- Resource Relation:
- Conference: ICEM'07: 11. International Conference on Environmental Remediation and Radioactive Waste Management, Bruges (Belgium), 2-6 Sep 2007; Other Information: Country of input: France; 23 refs.; Proceedings may be ordered from ASME Order Department, 22 Law Drive, P.O. Box 2300, Fairfield, NJ 07007-2300 (United States)
- Country of Publication:
- United States
- Language:
- English
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