Rheology of simulated radioactive waste slurry and cold cap during vitrification

Journal Article · Fri Jun 08 00:00:00 EDT 2018 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/jace.15755· OSTI ID:1441065

McCarthy, Benjamin P.  ^[1]; George, Jaime L.  ^[1]; Dixon, Derek R.  ^[1]; Wheeler, Michelle ^[1]; Cutforth, Derek A. ^[1]; Hrma, Pavel ^[1]; Linn, Diana ^[2]; Chun, Jaehun ^[2]; Hujova, Miroslava  ^[3]; Kruger, Albert A. ^[4]; Pokorny, Richard  ^[3]

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1. Radiological Materials &, Detection Group Pacific Northwest National Laboratory Richland Washington
2. Materials Sciences Group Pacific Northwest National Laboratory Richland Washington
3. Laboratory of Inorganic Materials Joint Workplace of the University of Chemistry and Technology Prague Prague 6 Czech Republic, The Institute of Rock Structure and Mechanics of the ASCR Prague 8 Czech Republic
4. Office of River Protection U.S. Department of Energy Richland Washington

Abstract During the vitrification of radioactive waste in a Joule‐heated melter, aqueous melter feed slurry forms a cold cap, a reacting and melting material, which floats on the surface of the molten glass. The rheological behavior of the feed affects cold cap formation and shape, and is vital for modeling the feed‐to‐melt conversion process. We used slurry feed simulant and fast‐dried slurry solids representing the cold cap to investigate the rheological behavior of the feed as it transforms into glass. Both low‐temperature and high‐temperature rheometry were performed and a new scheme was applied to estimate the feed viscosity. This study shows that the conversion advances in four sequential stages that form distinct regions in the cold cap: (i) a fast‐spreading boiling slurry from which water evaporates, (ii) a porous solid region (viscosity > 10 ⁸  Pa s) containing reacting solids and molten salts, (iii) a plastic region in which glass‐forming melt connects the refractory solids (~10 ⁸  to ~10 ⁶  Pa s), and (iv) a viscous foam layer in which the viscosity drops from ~10 ⁵  to ~10 ¹  Pa s. The implications for the mathematical modeling of the cold cap are discussed.

• Sponsoring Organization: USDOE
• OSTI ID: 1441065
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Vol. 101 Journal Issue: 11; ISSN 0002-7820
• Publisher: Wiley-Blackwell
• Country of Publication: United States
• Language: English