Observation of time dependent dispersion in laboratory scale experiments with intact tuff

Conference · Fri Dec 01 04:00:00 EST 1989

DOI:https://doi.org/10.1524/ract.1991.5253.1.219· OSTI ID:137561

Rundberg, R S; Triay, I R; Ott, M A; Mitchell, A J

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 Lab., 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
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
99 GENERAL AND MISCELLANEOUS
BARIUM 133
CESIUM 137
DISPERSIONS
HYDRODYNAMICS
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MEASURING METHODS
MINE SHAFTS
RADIOACTIVITY TRANSPORT
RADIONUCLIDE MIGRATION
SOLUTES
SORPTION
STRONTIUM 85
TECHNETIUM 95
TRACER TECHNIQUES
TRITIUM
TUFF
WELDING
YUCCA MOUNTAIN
Yucca Mountain Project
ZEOLITES