Transport in unsaturated flow systems using centrifuge techniques
- Washington State Univ., Richland (United States)
This report is a compilation of results from investigations on unsaturated flow and diffusion using the Unsaturated Flow Apparatus (UFA) in combination with other techniques at the Washington State University Tri-Cities Earth and Environmental Sciences Laboratory. These results bear directly on the goals of the Radionuclide Adsorption Workshop concerning experimental determination of unsaturated transport properties as stated in the First Report to the US congress and the US Department of Energy from the Nuclear Waste Technical Review Board. Transport parameters (diffusion coefficients, D({theta}), hydraulic conductivities, K({theta}), and retardation factors, R{sub f}) have been experimentally determined in unsaturated gravel, soil, bentonite and whole rock over a wide range of water contents in order to construct relationships of water content to each parameter for use in modeling of flow and transport in the near-field, far-field, and backfill environments. Once the water content was fixed at the target value and the system had achieved hydraulic steady-state, transport parameters were determined from associated methods, e.g., (1) the electrical conductivity of the sample was measured using a 1 kHz conductivity bridge and the diffusion coefficient calculated from the electrical conductivity using the Nernst-Einstein equation; (2) hydraulic conductivity was determined from the driving force and flux density; (3) the effluent was monitored/collected/analyzed for chemical interactions and retardation effects. These parameters have been investigated on different samples over the past two years since construction of the UFA. Project goals and specific milestones have resulted in diffusion coefficients of unsaturated gravel and soil being the most extensively studied parameter, but the UFA was originally designed to determine retardation factors and transient chemical interactions in unsaturated tuff. 35 refs., 20 figs.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- OSTI ID:
- 139665
- Report Number(s):
- LA-12325-C; CONF-9009350-; ON: DE92041241; TRN: 94:007289
- Resource Relation:
- Conference: DOE/Yucca Mountain site characterization project radionuclide adsorption workshop, Los Alamos, NM (United States), 11-12 Sep 1990; Other Information: PBD: Aug 1992; Related Information: Is Part Of Proceedings of the DOE/Yucca Mountain Site Characterization Project Radionuclide Adsorption Workshop at Los Alamos National Laboratory, September 11--12, 1990; Canepa, J.A.; PB: 238 p.
- Country of Publication:
- United States
- Language:
- English
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