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Resolving the Impact of Biological Processes on DNAPL Transport in Unsaturated Porous Media through Nuclear Magnetic Resonance Relaxation Time Measurements

Description: This research leads to a better understanding of how physical and biological properties of porous media influence water and dense non-aqueous phase liquid (DNAPL) distribution under saturated and unsaturated conditions. This project exploits the capability of low-field nuclear magnetic resonance (NMR) proton relaxation decay-rate measurements for determining environmental properties affecting DNAPL solvent flow in the subsurface, including determining if DNAPL exist in water-wet or solvent-wet environments, the pore-size distribution of the soils containing DNAPLs, and the impact of biological processes on their transport mechanisms in porous media. Knowledge of the in-situ flow properties and pore distributions of organic contaminants are critical to understanding where and when these fluids will enter subsurface aquifers.
Date: June 1, 2004
Creator: Hertzog, Russel & Geesey, Gill G.
Partner: UNT Libraries Government Documents Department

Multiphase flow in complex fracture apertures under a wide range of flow conditions

Description: The primary purpose of this project is to use a combination of computer modeling and laboratory experiments to obtain a better understanding of multiphase flow in geometrically complex fracture apertures under a wide range of flow conditions. Because traditional grid-based numerical methods perform poorly for multiphase flows with complex dynamic interfaces due to problems such as artificial interface broadening and grid entanglement, the modeling component of the program relies heavily on particle based methods. In particle-based models, the fluid-fluid interfaces move as the particles representing the fluids move--there is no need for explicit interface tracking, and no artificial front broadening. In addition, particle-based methods rigorously conserve mass because each particle represents a fixed mass of fluid and the number of particles does not change unless particles leave or enter the computational domain (to represent fluid flow into or out of the system). Because different model approaches have characteristic strengths and weaknesses, three different classes of particle-based models (lattice Boltzmann, dissipative particle dynamics and smoothed particle hydrodynamics) are being employed in this program. This will allow us to achieve our objective of simulating multiphase/multicomponent flow under a wide range of flow conditions for a wide range of fluid properties.
Date: June 1, 2004
Creator: Meakin, Paul; McCreery, Glenn E. & McEligot, Donald M.
Partner: UNT Libraries Government Documents Department

Applications of the 3-D Deterministic Transport Attila{reg_sign} for Core Safety Analysis

Description: An LDRD (Laboratory Directed Research and Development) project is ongoing at the Idaho National Engineering and Environmental Laboratory (INEEL) for applying the three-dimensional multi-group deterministic neutron transport code (Attila{reg_sign}) to criticality, flux and depletion calculations of the Advanced Test Reactor (ATR). This paper discusses the model development, capabilities of Attila, generation of the cross-section libraries, and comparisons to an ATR MCNP model and future.
Date: October 6, 2004
Creator: Lucas, D.S.; Gougar, D.; Roth, P.A.; Wareing, T.; Failla, G.; McGhee, J. et al.
Partner: UNT Libraries Government Documents Department

Coupling of Realistic Rate Estimates with Genomics for Assessing Contaminant Attenuation and Long-Term Plume Containment

Description: Dissolved dense nonaqueous-phase liquid plumes are persistent, widespread problems in the DOE complex. At the Idaho National Engineering and Environmental Laboratory, dissolved trichloroethylene (TCE) is disappearing from the Snake River Plain aquifer (SRPA) by natural attenuation, a finding that saves significant site restoration costs. Acceptance of monitored natural attenuation as a preferred treatment technology requires direct evidence of the processes and rates of the degradation. Our proposal aims to provide that evidence for one such site by testing two hypotheses. First, we believe that realistic values for in situ rates of TCE cometabolism can be obtained by sustaining the putative microorganisms at the low catabolic activities consistent with aquifer conditions. Second, the patterns of functional gene expression evident in these communities under starvation conditions while carrying out TCE cometabolism can be used to diagnose the cometabolic activity in the aquifer itself. Using the cometabolism rate parameters derived in low-growth bioreactors, we will complete the models that predict the time until background levels of TCE are attained at this location and validate the long-term stewardship of this plume. Realistic terms for cometabolism of TCE will provide marked improvements in DOE's ability to predict and monitor natural attenuation of chlorinated organics at other sites, increase the acceptability of this solution, and provide significant economic and health benefits through this noninvasive remediation strategy. Finally, this project aims to derive valuable genomic information about the functional attributes of subsurface microbial communities upon which DOE must depend to resolve some of its most difficult contamination issues.
Date: June 1, 2005
Creator: Colwell, F. S.; Crawford, R. L. & Sorenson, K.
Partner: UNT Libraries Government Documents Department

Real-Time Soil Characterization and Analysis Systems Used at US Department of Energy Closure Sites in Ohio

Description: The Idaho National Engineering and Environmental Laboratory (INEEL) and the Fernald Environmental Management Project (FEMP) have jointly developed a field-deployed analytical system to rapidly scan, characterize, and analyze surface soil contamination. The basic system consists of a sodium iodide (NaI) spectrometer and global positioning system (GPS) hardware. This hardware can be deployed from any of four different platforms depending on the scope of the survey at hand. These platforms range from a large tractor-based unit (the RTRAK) used to survey large, relatively flat areas to a hand-pushed unit where maneuverability is important, to an excavator mounted system used to scan pits and trenches. The mobile sodium iodide concept was initially developed by the FEMP to provide pre-screening analyses for soils contaminated with uranium, thorium, and radium. The initial study is documented in the RTRAK Applicability Study and provides analyses supporting the field usage of the concept. The RTRAK system produced data that required several days of post-processing and analyses to generate an estimation of field coverage and activity levels. The INEEL has provided integrated engineering, computer hardware and software support to greatly streamline the data acquisition and analysis process to the point where real-time activity and coverage maps are available to the field technicians. On-line analyses have been added to automatically convert GPS data to Ohio State-Plane coordinates, examine and correct collected spectra for energy calibration drifts common to NaI spectrometers, and strip spectra in regions of interest to provide moisture corrected activity levels for total uranium, thorium-232, and radium-226. Additionally, the software provides a number of checks and alarms to alert operators that a hand-examination of spectral data in a particular area may be required. The FEMP has estimated that this technology has produced projected site savings in excess of $34M through FY 2006. Additionally, the INEEL has applied ...
Date: February 25, 2003
Creator: Roybal, L. G.; Carpenter, M. V.; Giles, J. R. & Danahy, R. J.
Partner: UNT Libraries Government Documents Department

Calcite Precipitation and Trace Metal Partitioning in Groundwater and the Vadose Zone: Remediation of Strontium-90 and Other Divalent Metals and Radionuclides in Arid Western Environments

Description: Radionuclide and metal contaminants are present in the vadose zone and groundwater throughout the U.S. Department of Energy (DOE) weapons complex. Demonstrating in situ immobilization of these contaminants in vadose zones or groundwater plumes is a cost-effective remediation strategy. However, the implementation of in situ remediation requires definition of the mechanism that controls sequestration of the contaminants. One such mechanism for metals and radionuclides is co-precipitation of these elements in authigenic calcite and calcite overgrowths. Calcite, a common mineral in many aquifers and vadose zones in the arid western U.S., can incorporate divalent metals such as strontium, cadmium, lead, and cobalt into its crystal structure by the formation of solid solutions. The rate at which trace metals are incorporated into calcite is a function of calcite precipitation kinetics, adsorption interactions between the calcite surface and the trace metal in solution, solid solution properties of the trace metal in calcite, and also the surfaces upon which the calcite is precipitating. A fundamental understanding of the coupling of calcite precipitation and trace metal partitioning and how this may occur in aquifers and vadose environments is lacking. The focus of the research proposed here is to investigate the facilitated partitioning of metal and radionuclides by their coprecipitation with calcium carbonate. Our specific research objectives include: (1) Elucidating the mechanisms and rates of microbially facilitated calcite precipitation and divalent cation adsorption/co-precipitation occurring in a natural aquifer as a result of the introduction of urea. (2) Assessing the effects of spatial variability in aquifer host rock and the associated hydro/biogeochemical processes on calcite precipitation rates and mineral phases within an aquifer.
Date: August 9, 2001
Creator: Smith, Robert W.; Colwell, F. ''Rick'' S.; Ingram, Jani C.; Ferris, F. Grant & Reysenbach, Anna-Louise
Partner: UNT Libraries Government Documents Department

Enhancing Effectiveness of EMSP Projects Through Strong Connections to Site Problems

Description: The Environmental Management Science Program (EMSP) funds basic science research that will lead to reduced remediation cost, schedule, technical uncertainties, and risk for DOE's environmental clean up. The Tanks Focus Area (TFA) has partnered with EMSP to accomplish those same objectives for DOE's largest and most expensive remediation effort--to retrieve and immobilize the highly radioactive wastes that are our nation's chief nuclear defense program legacy. TFA has been tasked to facilitate success of the EMSP investment. The key for EMSP projects to contribute to this remediation effort is communication. First, scientists need to understand much more about how their scientific results would be used than they could ever learn from the original EMSP solicitation or by reading the referenced DOE needs statements. Second, the scientists' results must be communicated to the site problem holders in a usable form and in a timely manner such that important information gaps can still be filled by the EMSP project. Research results can be used in a variety of ways besides deployment of new hardware or a new process. When results are USED the site problem holders become ''users''. The important aspect that research results are to be used is captured in the TFA lexicon for their clients, the DOE sites--''users''. This paper will show, through several examples, significant contributions EMSP scientists have made to solving DOE's high-level waste challenges through direct and enhanced communication with TFA and site users.
Date: February 25, 2002
Creator: Guillen, D. P. & Josephson, G. B.
Partner: UNT Libraries Government Documents Department

Calcite Precipitation and Trace Metal Partitioning in Groundwater and the Vadose Zone: Remediation of Strontium-90 and Other Divalent Metals and Radionuclides in Arid Western Environments

Description: Radionuclide and metal contaminants are present in the vadose zone and groundwater throughout the U.S. Department of Energy (DOE) weapons complex. Demonstrating in situ immobilization of these contaminants in vadose zones or groundwater plumes is a cost-effective remediation strategy. However, the implementation of in situ remediation requires definition of the mechanism that controls sequestration of the contaminants. One such mechanism for metals and radionuclides is co-precipitation of these elements in authigenic calcite and calcite overgrowths. Calcite, a common mineral in many aquifers and vadose zones in the arid western U.S., can incorporate divalent metals such as strontium, cadmium, lead, and cobalt into its crystal structure by the formation of solid solutions. The rate at which trace metals are incorporated into calcite is a function of calcite precipitation kinetics, adsorption interactions between the calcite surface and the trace metal in solution, solid solution properties of the trace metal in calcite, and also the surfaces upon which the calcite is precipitating. A fundamental understanding of the coupling of calcite precipitation and trace metal partitioning and how this may occur in aquifers and vadose environments is lacking. The focus of the research proposed here is to investigate the facilitated partitioning of metal and radionuclides by their coprecipitation with calcium carbonate. Our specific research objectives include: (1) Elucidating the mechanisms and rates of microbially facilitated calcite precipitation and divalent cation adsorption/co-precipitation occurring in a natural aquifer and vadose zone perched water body as a result of the introduction of urea. (2) Assessing the effects of spatial variability in aquifer host rock and the associated hydro/biogeochemical processes on calcite precipitation rates and mineral phases within an aquifer and a vadose zone perched water body.
Date: July 19, 2000
Creator: Smith, Robert W.; Colwell, F. ''Rick'' S.; Ingram, Jani C.; Ferris, F. Grant & Reysenbach, Anna-Louise
Partner: UNT Libraries Government Documents Department

The Nuclear Material Focus Area Roadmapping Process Utilizing Environmental Management Complex-Wide Nuclear Material Disposition Pathways

Description: This paper describes the process that the Nuclear Materials Focus Area (NMFA) has developed and utilizes in working with individual Department of Energy (DOE) sites to identify, address, and prioritize research and development efforts in the stabilization, disposition, and storage of nuclear materials. By associating site technology needs with nuclear disposition pathways and integrating those with site schedules, the NMFA is developing a complex wide roadmap for nuclear material technology development. This approach will leverage technology needs and opportunities at multiple sites and assist the NMFA in building a defensible research and development program to address the nuclear material technology needs across the complex.
Date: February 26, 2002
Creator: Sala, D. R.; Furhman, P. & Smith, J. D.
Partner: UNT Libraries Government Documents Department

HARVESTING EMSP RESEARCH RESULTS FOR WASTE CLEANUP

Description: The extent of environmental contamination created by the nuclear weapons legacy combined with expensive, ineffective waste cleanup strategies at many U.S. Department of Energy (DOE) sites prompted Congress to pass the FY96 Energy and Water Development Appropriations Act, which directed the DOE to: ''provide sufficient attention and resources to longer-term basic science research, which needs to be done to ultimately reduce cleanup costs'', ''develop a program that takes advantage of laboratory and university expertise, and'' ''seek new and innovative cleanup methods to replace current conventional approaches which are often costly and ineffective.'' In response, the DOE initiated the Environmental Management Science Program (EMSP)-a targeted, long-term research program intended to produce solutions to DOE's most pressing environmental problems. EMSP funds basic research to lower cleanup cost and reduce risk to workers, the public, and the environment; direct the nation's scientific infrastructure towards cleanup of contaminated waste sites; and bridge the gap between fundamental research and technology development activities. EMSP research projects are competitively awarded based on the project's scientific, merit coupled with relevance to addressing DOE site needs. This paper describes selected EMSP research projects with long, mid, and short-term deployment potential and discusses the impacts, focus, and results of the research. Results of EMSP research are intended to accelerate cleanup schedules, reduce cost or risk for current baselines, provide alternatives for contingency planning, or provide solutions to problems where no solutions exist.
Date: February 27, 2003
Creator: Guillen, Donna Post; Nielson, R. Bruce; Phillips, Ann Marie & Lebow, Scott
Partner: UNT Libraries Government Documents Department

EVALUATION OF HDPE CONTAINERS FOR MACROENCAPSULATION OF MIXED WASTE DEBRIS

Description: Macroencapsulation is currently available at facilities permitted by the U.S. Environmental Protection agency for the treatment of radioactively contaminated hazardous waste. The U.S. Department of Energy is evaluating the use of high-density polyethylene containers to provide a simpler means of meeting macroencapsulation requirements. Macroencapsulation is used for the purpose of isolating waste from the disposal environment in order to meet the Land Disposal Restriction treatment standards for debris-like waste. The containers being evaluated have the potential of providing a long-term reduction in the leachability and subsequent mobility of both the hazardous and radioactive contaminants in this waste while at the same allowing treatment by the generator as the waste is being generated. While the testing discussed in this paper shows that further developmental work is necessary, these tests also indicate that these containers have the potential to reduce the cost, schedule, and complexity of meeting the treatment standard for mixed waste debris.
Date: February 27, 2003
Creator: Eaton, David; Carlson, Tim; Gardner, Brad; Bushmaker, Robert; Battleson, Dan; Shaw, Mark et al.
Partner: UNT Libraries Government Documents Department