Results of Performance Evaluation Testing of Electrical Leak-Detection Methods at the Hanford Mock Tank Site--FY 2002-2003

Barnett, D. Brent; Gee, Glendon W.; Sweeney, Mark D.; Johnson, Michael D.; Medina, Victor F.; Mendoza, Donaldo P.; Fritz, Brad G.; Khan, Fenton; Daily, William; Fink, James B.; Levitt, Marc T.; Binley, Andrew

doi:10.2172/15010193

Cited by 4 publications

(3 citation statements)

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“…For testing, an electrical tracer (saline solution) was used instead of the real contaminant to preserve the environmental quality of the test site. The test site used for this work is part of the 200 east area in the Hanford site, located near Richland, Washington (additional details about the test site and testing are provided by Barnett et al [2002, 2003]). The near‐surface sediments at the test site consist primarily of fine to coarse‐grained sand with an average fractional porosity of 0.25 to 0.30.…”

Section: Resultsmentioning

confidence: 99%

“…[61] Electrical resistance data were collected during a field experiment that simulated leakage from a large metallic tank. Barnett et al [2002Barnett et al [ , 2003). The near-surface sediments at the test site consist primarily of fine to coarse-grained sand with an average fractional Figure 7 shows the layout at the experimental site.…”

Section: Field Results: Tank Leak Detectionmentioning

confidence: 99%

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Stochastic inversion of electrical resistivity changes using a Markov Chain Monte Carlo approach

et al. 2005

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[1] We describe a stochastic inversion method for mapping subsurface regions where the electrical resistivity is changing. The technique combines prior information, electrical resistance data, and forward models to produce subsurface resistivity models that are most consistent with all available data. Bayesian inference and a Metropolis simulation algorithm form the basis for this approach. Attractive features include its ability (1) to provide quantitative measures of the uncertainty of a generated estimate and (2) to allow alternative model estimates to be identified, compared, and ranked. Methods that monitor convergence and summarize important trends of the posterior distribution are introduced. Results from a physical model test and a field experiment were used to assess performance. The presented stochastic inversions provide useful estimates of the most probable location, shape, and volume of the changing region and the most likely resistivity change. The proposed method is computationally expensive, requiring the use of extensive computational resources to make its application practical.

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Section: Resultsmentioning

confidence: 99%

Section: Field Results: Tank Leak Detectionmentioning

confidence: 99%

Stochastic inversion of electrical resistivity changes using a Markov Chain Monte Carlo approach

et al. 2005

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“…Both the point-electrode and long-electrode configurations have since been tested at the mock tank site as a potential technology for leak detection and monitoring to support tank retrieval operations (Barnett et al 2003), but the technology was not selected for implementation.…”

Section: Synopsis and Implicationsmentioning

confidence: 99%

Vadose Zone Transport Field Study: Summary Report

Ward¹,

Conrad²,

Daily³

et al. 2006

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SummaryA series of field studies were conducted at the Hanford Site, near Richland, Washington, from FY 2000 through FY 2003 at two different locations to develop data sets to test models of flow and transport in the vadose zone. The field studies were also done to investigate advanced monitoring techniques for evaluating flow-and-transport mechanisms and delineating contaminant plumes in the vadose zone at the Hanford Site. The studies were conducted as part of the Groundwater/Vadose Zone Integration Project Science and Technology Project, now known as the Remediation and Closure Science Project, managed by the Pacific Northwest National Laboratory (PNNL) and supported by the U.S. Department of Energy, Richland Operations Office. This report summarizes the key findings from the field studies and demonstrates how data collected from these studies are being used to improve conceptual models and develop numerical models of flow and transport in Hanford's vadose zone. Results from the field studies and associated analysis have appeared in more than 46 publications generated over the past 4 years. These publications include test plans and status reports in addition to numerous technical notes and papers.Two major field campaigns were performed, one at a well injection test site and a second at a clastic dike test site. Both field studies have resulted in field-scale transport parameters for Hanford conditions, which are useful for improving predictions of subsurface flow and transport at the Hanford Site. In addition, advanced geophysical methods, including high resolution electrical resistivity measurements, were successfully tested and are now being deployed at Hanford for subsurface investigations and tank retrieval detection. The most useful information gained from these studies has been a better understanding of flow and transport in the vadose zone, and this has been specifically related to the impact of small-scale stratigraphic features (e.g., sediment layering) on water flow and contaminant transport. Conceptual models have been developed that take into account the lateral spreading of water and contaminants observed in the field studies. Numerical models of unsaturated flow and transport have been revised to account for lateral spreading of subsurface contaminant plumes.The key results from these studies include: 1) Greater understanding of the complexity of plume migration in the vadose zone at Hanford. Finescale geologic heterogeneities, including grain fabric and lamination, were observed to have a strong effect on the large-scale behavior of contaminant plumes, primarily through increased lateral spreading resulting from anisotropy.2) Observations of anion exclusion in Hanford sediments. Anion exclusion is a mechanism by which negatively charged ions are repelled from the surfaces of negatively charged soil particles, thereby increasing their velocity. Thus, the travel time of ions like pertechnetate, the stable form of 99 Tc found in oxidized environments, may decrease over that of unsaturated water f...

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