Nuclear waste glass leaching in a simulated granite repository
Burial experiments of three Savannah River Laboratory (SRL) and three Swedish alkali borosilicate (ABS) simulated nuclear waste glasses were conducted to evaluate the resistance of these glasses to ground water attack under repository-like conditions. Glass samples were buried in the boreholes at a depth of about 350 meters below the surface in the Stripa granite at either ambient mine temperature (8-10/sup 0/C) or 90/sup 0/C. Included in the same boreholes were other potential waste package components. Glasses were also leached in the Stripa ground water contained in a leaching vessel under the laboratory simulation conditions. The leached surfaces were characterized using SEM-EDS, FT-IRRS, SIMS, RBS and optical microscopy. Differences in glass leach rate were observed among the six compositions with SRL 165 + 29.8% TDS being the lowest. Results show that durabilities of the SRL composite nuclear waste glasses were increased by approximately six times when frit 131 was substituted by frit 165. An increase of waste loading of SRL 131 glass from 29.8 to 35 wt% decreases the leachability by a factor of 2. The leach rates of buried samples based on boron extraction at 90/sup 0/C ranged from 0.3-3 ..mu..m/year for the glass/glass interfaces of all glass formulations. These values are at least two orders of magnitude lower than those for glasses leached using MCC-1 static leaching procedures and deionized water. The Stripa repository-like conditions can be simulated in the laboratory using Stripa ground water and high SA/V ratios (greater than or equal to 1.0 cm/sup -1/). Comparison of the laboratory test results with field test results indicates that glass leaching mechanisms were similar under these test conditions.
- Research Organization:
- Florida Univ., Gainesville (USA)
- OSTI ID:
- 7150930
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
BOREHOLES
CAVITIES
DISSOLUTION
GLASS
GRANITES
GROUND DISPOSAL
IGNEOUS ROCKS
LEACHING
MANAGEMENT
MATERIALS
PLUTONIC ROCKS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
ROCKS
SEPARATION PROCESSES
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES