Strontium leachability of hydrofracture grouts for sludge-slurries
This report summarizes the results obtained from a series of experiments performed to determine the strontium leachability of cement-based sludge-slurry hydrofracture grouts. These grouts simulate those that will be used to dispose of the radioactive sludges now stored at Oak Ridge National Laboratory. The hydrofracture process has been used at ORNL since 1966 for the routine disposal of intermediate-level waste solutions. In this process, cement and other additives are mixed with a waste stream to form a grout, which is then injected into a shale bed at a pressure sufficient to cause fracture along the horizontal bedding planes. The injected grout soon hardens, fixing the radionuclides between the layers of the massive Conasauga shale formation. A new hydrofracture facility has been constructed to dispose of residual sludges that have accumulated at ORNL from the NaOH neutralization of acid waste solutions. These sludges will be slurried with bentonite and pumped from the 37-year-old Gunite storage tanks to the holding tanks at the new hydrofracture facility. Pumpable grouts will be prepared by mixing the sludges with cement and other additives prior to injection in the shale bed. The specimens used in the tests reported here were prepared within the working boundary conditions of the rheogram for pumpable hydrofracture grouts. The results of applying the modified IAEA dynamic leach tests to hydrofracture grout specimens showed improved leach resistance (by a factor of 3 to 5 ) as the curing time was increased from 28 to 91 d and a weak trend toward lower leachability as increased amounts of dry solids were added. The Joy-Godbee leach model fit the dynamic leach data successfully in most cases. An apparent diffusion coefficient of 5 x 10/sup -12/ cm/sup 2//s and a moving boundary coefficient of 1 x 0/sup -7/ s/sup -1/ were obtained for one of the best grout compositions when leached in distilled water.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 5255673
- Report Number(s):
- ORNL/TM-8198; ON: DE82009316; TRN: 82-012997
- Resource Relation:
- Other Information: Portions of document are illegible
- Country of Publication:
- United States
- Language:
- English
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36 MATERIALS SCIENCE
HYDRAULIC FRACTURING
GROUTING
RADIOACTIVE WASTE DISPOSAL
STRONTIUM
LEACHING
CEMENTS
EXPERIMENTAL DATA
INTERMEDIATE-LEVEL RADIOACTIVE WASTES
SLUDGES
SLURRIES
UNDERGROUND DISPOSAL
ALKALINE EARTH METALS
BUILDING MATERIALS
COMMINUTION
DATA
DISPERSIONS
DISSOLUTION
ELEMENTS
FRACTURING
INFORMATION
MANAGEMENT
MATERIALS
METALS
MIXTURES
NUMERICAL DATA
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
SEPARATION PROCESSES
SUSPENSIONS
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
052002* - Nuclear Fuels- Waste Disposal & Storage
360604 - Materials- Corrosion
Erosion
& Degradation