High-temperature leaching of an actinide-bearing, simulated high-level waste glass
The chemical durability of a simulated high-level waste glass when exposed to high-temperature geologic solutions was investigated. In this study, simulated high-level waste glass-beads (76 to 68 glass)l doped with technetium, uranium, neptunium, plutonium, curium and americium were leached in deionized water, Waste Isolation Pilot Plant salt brine B, and 0.03M sodium bicarbonate solution at 150 and 250/sup 0/C for 2, 4, 8, 16, and 32 days. The resulting solutions were analyzed for several nonradioactive glass components and for the radioactive dopants. The glass exhibited incongruent leaching behavior, i.e., the normalized releases (g-glass/m/sup 2/) based on the different elements spanned four orders of magnitude. Normalized releases based on boron, molybdenum, sodium, cesium, silicon, and technetium were the same within a factor of three. Most of the nonradioactive components of the glass were released more to the salt brine than to the other two solutions. However, silicon, boron, molybdenum, technetium, and the actinides had their lowest releases in the salt brine. Reaction-layer thickness on the glass surface and weight losses of the glass beads were also smallest in the brine solution. Actinide releases were highest in the sodium bicarbonate solution. Calcium, strontium and barium releases decreased with time and temperature; the releases of most other elements increased with time and temperature. Solubility appears to be limiting the release of most elements. The leachate pH is controlled by chemical species within the original leachant and by species released as the glass leached. Carbonate ion complexes with some elements including uranium, effectively increasing their release. The more soluble elements including sodium, boron, molybdenum and technetium provide an indication of the actual rate of reaction between the glass and water.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 6494366
- Report Number(s):
- PNL-3172; ON: DE83008755
- Resource Relation:
- Other Information: Portions are illegible in microfiche products. Original copy available until stock is exhausted
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
GLASS
LEACHING
TEMPERATURE EFFECTS
AMERICIUM
BORON
BRINES
CESIUM
CURIUM
HIGH-LEVEL RADIOACTIVE WASTES
MOLYBDENUM
NEPTUNIUM
PLUTONIUM
RADIOACTIVE WASTE DISPOSAL
SALT DEPOSITS
SILICON
SIMULATION
SODIUM
SODIUM CARBONATES
TECHNETIUM
UNDERGROUND DISPOSAL
URANIUM
WATER
ACTINIDES
ALKALI METAL COMPOUNDS
ALKALI METALS
CARBON COMPOUNDS
CARBONATES
DISSOLUTION
ELEMENTS
GEOLOGIC DEPOSITS
HYDROGEN COMPOUNDS
MANAGEMENT
MATERIALS
METALS
OXYGEN COMPOUNDS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
SEMIMETALS
SEPARATION PROCESSES
SODIUM COMPOUNDS
TRANSITION ELEMENTS
TRANSPLUTONIUM ELEMENTS
TRANSURANIUM ELEMENTS
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
052002* - Nuclear Fuels- Waste Disposal & Storage
360604 - Materials- Corrosion
Erosion
& Degradation