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Title: Simulation of unsaturated flow and solute transport at the Las Cruces trench site using the PORFLO-3 computer code

The objective of this work was to test the ability of the PORFLO-3 computer code to simulate water infiltration and solute transport in dry soils. Data from a field-scale unsaturated zone flow and transport experiment, conducted near Las Cruces, New Mexico, were used for model validation. A spatial moment analysis was used to provide a quantitative basis for comparing the mean simulated and observed flow behavior. The scope of this work was limited to two-dimensional simulations of the second experiment at the Las Cruces trench site. Three simulation cases are presented. The first case represents a uniform soil profile, with homogeneous, isotropic hydraulic and transport properties. The second and third cases represent single stochastic realizations of randomly heterogeneous hydraulic conductivity fields, generated from the cumulative probability distribution of the measured data. Two-dimensional simulations produced water content changes that matched the observed data reasonably well. Models that explicitly incorporated heterogeneous hydraulic conductivity fields reproduced the characteristics of the observed data somewhat better than a uniform, homogeneous model. Improved predictions of water content changes at specific spatial locations were obtained by adjusting the soil hydraulic properties. The results of this study should only be considered a qualitative validation of the PORFLO-3 code.more » However, the results of this study demonstrate the importance of site-specific data for model calibration. Applications of the code for waste management and remediation activities will require site-specific data for model calibration before defensible predictions of unsaturated flow and containment transport can be made. 23 refs., 16 figs., 3 tabs.« less
Authors:
;
Publication Date:
OSTI Identifier:
6036996
Report Number(s):
PNL-7562
ON: DE91009730; TRN: 91-010446
DOE Contract Number:
AC06-76RL01830
Resource Type:
Technical Report
Research Org:
Pacific Northwest Lab., Richland, WA (USA)
Sponsoring Org:
DOE; USDOE, Washington, DC (USA)
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; NUCLEAR FACILITIES; RADIOACTIVE WASTE MANAGEMENT; REMEDIAL ACTION; SITE CHARACTERIZATION; P CODES; ACCURACY; BATTELLE PACIFIC NORTHWEST LABORATORIES; BENCHMARKS; COMPUTER CODES; COMPUTERIZED SIMULATION; DOCUMENTATION; ENVIRONMENTAL TRANSPORT; EXPERIMENTAL DATA; FIELD TESTS; FLOW MODELS; GEOLOGY; HANFORD RESERVATION; HYDRAULICS; HYDROLOGY; ITERATIVE METHODS; MASS BALANCE; MASS TRANSFER; METEOROLOGY; NEW MEXICO; NONLINEAR PROBLEMS; PROBABILITY; RADIONUCLIDE MIGRATION; SOILS; TRITIUM; TWO-DIMENSIONAL CALCULATIONS; US NRC; VALIDATION; VERIFICATION; WATER INFLUX; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; DATA; FEDERAL REGION VI; FLUID MECHANICS; HYDROGEN ISOTOPES; INFORMATION; ISOTOPES; LIGHT NUCLEI; MANAGEMENT; MATHEMATICAL MODELS; MECHANICS; NATIONAL ORGANIZATIONS; NORTH AMERICA; NUCLEI; NUMERICAL DATA; ODD-EVEN NUCLEI; RADIOISOTOPES; SIMULATION; TESTING; US DOE; US ERDA; US ORGANIZATIONS; USA; WASTE MANAGEMENT; YEARS LIVING RADIOISOTOPES 052000* -- Nuclear Fuels-- Waste Management; 054000 -- Nuclear Fuels-- Health & Safety