Control of high level radioactive waste-glass melters. Part 5, Modelling of complex redox effects
Slurry Fed Melters (SFM) are being developed in the United States, Europe and Japan for the conversion of high-level radioactive waste to borosilicate glass for permanent disposal. The high transition metal, noble metal, nitrate, organic, and sulfate contents of these wastes lead to unique melter redox control requirements. Pilot waste-glass melter operations have indicated the possibility of nickel sulfide or noble-metal fission-product accumulation on melter floors, which can lead to distortion of electric heating patterns, and decrease melter life. Sulfide formation is prevented by control of the redox chemistry of the melter feed. The redox state of waste-glass melters is determined by balance between the reducing potential of organic compounds in the feed, and the oxidizing potential of gases above the melt, and nitrates and polyvalent elements in the waste. Semiquantitative models predicting limitations of organic content have been developed based on crucible testing. Computerized thermodynamic computations are being developed to predict the sequence and products of redox reactions and is assessing process variations. Continuous melter test results have been compared to improved computer staged-thermodynamic-models of redox behavior. Feed chemistry control to prevent sulfide and moderate noble metal accumulations are discussed. 17 refs., 3 figs.
- Research Organization:
- Westinghouse Savannah River Co., Aiken, SC (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC09-89SR18035
- OSTI ID:
- 10131152
- Report Number(s):
- WSRC-MS-91-101; CONF-9104256-11-Pt.5; ON: DE92009533
- Resource Relation:
- Conference: Symposium on nuclear waste management,Cincinnati, OH (United States),28 Apr - 2 May 1991; Other Information: PBD: [1991]
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
MELTING
THERMODYNAMIC MODEL
HIGH-LEVEL RADIOACTIVE WASTES
VITRIFICATION
REDOX REACTIONS
BOROSILICATE GLASS
SLURRIES
EVAPORATORS
COMPUTER CALCULATIONS
NICKEL SULFIDES
052001
400201
WASTE PROCESSING
CHEMICAL AND PHYSICOCHEMICAL PROPERTIES