2001 Technical Reports
FY00 Initial Assessments for S-SX Field Invistigation Report(FIR): Simulations of Contaminant Migration with Surface Barriers
M. D. White, M. Oostrom, M. D. Williams, C. R. Cole, M. P. Bergeron
Battelle, Pacific Northwest Division, Richland, WA
PNWD-3111, Battelle, Pacific Northwest Division, Richland, Wa, 2001.
Summary
In support of CH2M Hill Hanford Group, Inc.'s (CHG) preparation of a Field Investigative Report (FIR) for the Hanford Site Single-Shell Tank Waste Management Area (WMA) S-SX, a suite of numerical simulations of flow and solute transport were executed to predict the performance of surface barriers for reducing long-term risks from potential groundwater contamination at the S-SX WMA. The scope and parametric data for these simulations were defined by a modeling data package provided by CHG. This report documents the simulation of fourteen cases invovling two-dimensional cross-sections through the S-SX WMA and one three-dimensional domain of a single tank (quarter symmetry) within the S-SX WMA. The suite of two-dimensional simulations were used to investigate the impact of surface barriers, waterline leaks, clastic dikes, nonuniform inventories, inventories displaced toward the watertable, concentration dependent density and viscosity for the transporting fluid (i.e., water), and meteoric recharge. The three-dimensional simulation was used to investigate the impact of dimensionality on the numerical predictions. Four transported solutes were considered: technetium-99 (Tc-99), cesium-137 (Cs-137), nitrate (NO3), and chromium (Cr).
Rapid Migration of Radionuclides Leaked from High-Level Water Tanks: A Study of Salinity Gradients, Wetted Path Geometry and Water Vapor Transport
A. L. Ward1, G. W. Gee1, J. S. Selker2, C. Cooper3
1Pacific Northwest National Laboratory, Richland, WA
2Oregon State University, Corvallis, OR
3Division of Hydrologic Sciences, Desert Research Institute, Reno, NV
PNNL-65410 Pacific Northwest National Laboratory, Richland WA, 2001
Summary
The basis of this study was the hypothesis that the physical and chemical properties of hypersaline tank waste could lead to wetting front instability and fingered flow following a tank leak. Thus, the goal of this project was to develop an understanding of the impacts of the properties of hypersaline fluids on transport through the unsaturated zone beneath Hanford's Tank Farms. There were three specific objectives (i) to develop an improved conceptualization of hypersaline fluid transport in laboratory (ii) to identify the degree to which field conditions mimic the flow processes observed in the laboratory and (iii) to provide a validation data set to establish the degree to which the conceptual models, embodied in a numerical simulator, could explain the observed field behavior.