title: Temperature Distribution within a Cold Cap during Nuclear Waste Vitrification.
abstract: The kinetics of the feed-to-glass conversion affects the waste vitrification rate in an electric glass melter. The primary area of interest in this conversion process is the cold cap, a layer of reacting feed on top of the molten glass. The work presented here provides an experimental determination of the temperature distribution within the cold cap. Because direct measurement of the temperature field within the cold cap is impracticable, an indirect method was developed in which the textural features in a laboratory-made cold cap with a simulated high-level waste feed were mapped as a function of position using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The temperature distribution within the cold cap was established by correlating microstructures of cold-cap regions with heat-treated feed samples of nearly identical structures at known temperatures. This temperature profile was compared with a mathematically simulated profile generated by a cold-cap model that has been developed to assess the rate of glass production in a melter.
authors.affiliation: †Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States.
authors.forename: Derek R
authors.initials: DR
authors.lastname: Dixon
authors.affiliation: †Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Schweiger
authors.affiliation: †Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Riley
authors.affiliation: ‡Department of Chemical Engineering, University of Chemistry and Technology Prague, Technicka 5, 166 28 Prague 6, Czech Republic.
authors.forename: Richard
authors.initials: R
authors.lastname: Pokorny
authors.affiliation: †Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States.
authors.forename: Pavel
authors.initials: P
authors.lastname: Hrma
mesh_terms: D003080:Cold Temperature; D005898:Glass / Q000737:chemistry; D008962:Models, Theoretical; D011850:Radioactive Waste / Q000032:analysis*; D013052:Spectrometry, X-Ray Emission; D058989:Vitrification; D014961:X-Ray Diffraction
chemical_list: D011850:Radioactive Waste