Observation of time dependent dispersion in laboratory scale experiments with intact tuff
The migration of radionuclides through intact tuff was studied using tuff from Yucca Mountain, Nevada. The tuff samples were both highly zeolitized ash-fall tuff from the Calico Hills and densely welded devitrified tuff from the Topopah Springs member of the Paintbrush tuff. Tritiated water and pertechnetate were used as conservative tracers. The sorbing tracers {sup 85}Sr, {sup 137}Cs, and {sup 133}Ba were used with the devitrified tuff only. Greater tailing in the elution curves of the densely welded tuff samples was observed that could be fit by adjusting the dispersion coefficient in the conventional Advection Dispersion Equation, ADE. The curves could be fit using time dependent dispersion as was previously observed for sediments and alluvium by Dieulin, Matheron, and de Marsily. The peak of strontium concentration was expected to arrive after 1.5 years based on the conventional ADE and assuming a linear K{sub d} of 26 ml/g. The observed elution had significant strontium in the first sample taken at 2 weeks after injection. The peak in the strontium elution occurred at 5 weeks. The correct arrival time for the strontium peak was achieved using a one dimensional analytic solution with time dependent dispersion. The dispersion coefficient as a function of time used to fit the conservative tracers was found to predict the peak arrival of the sorbing tracers. The K{sub d} used was the K{sub d} determined by the batch method on crushed tuff. 23 refs., 9 figs., 2 tabs.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 137561
- Report Number(s):
- LA-UR-89-3734; CONF-891120-7; ON: DE90003190; TRN: 90:001274
- Resource Relation:
- Journal Volume: 52-53; Journal Issue: 1; Conference: Migration `89: 2nd international conference on chemistry and migration behavior of actinides and fission products in the geosphere, Monterey, CA (United States), 6-10 Nov 1989; Other Information: PBD: 1989
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
99 MATHEMATICS
COMPUTERS
INFORMATION SCIENCE
MANAGEMENT
LAW
MISCELLANEOUS
YUCCA MOUNTAIN
TUFF
SORPTION
STRONTIUM 85
RADIONUCLIDE MIGRATION
CESIUM 137
BARIUM 133
DISPERSIONS
RADIOACTIVITY TRANSPORT
ZEOLITES
WELDING
TRACER TECHNIQUES
SOLUTES
TRITIUM
MINE SHAFTS
HYDRODYNAMICS
TECHNETIUM 95
MATHEMATICAL MODELS
MEASURING METHODS
MEASURING INSTRUMENTS
Yucca Mountain Project