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Modeling and Simulation of Long-Term Performance of Near-Surface Barriers (open access)

Modeling and Simulation of Long-Term Performance of Near-Surface Barriers

Society has and will continue to generate hazardous wastes whose risks must be managed. For exceptionally toxic, long-lived, and feared waste, the solution is deep burial, e.g., deep geological disposal at Yucca Mtn. For some waste, recycle or destruction/treatment is possible. The alternative for other wastes is storage at or near the ground level (in someone’s back yard); most of these storage sites include a surface barrier (cap) to prevent migration of the waste due to infiltration of surface water. The design lifespan for such barriers ranges from 30 to 1000 years, depending on hazard and regulations. In light of historical performance, society needs a better basis for predicting barrier performance over long time periods and tools for optimizing maintenance of barriers while in service. We believe that, as in other industries, better understanding of the dynamics of barrier system degradation will enable improved barriers (cheaper, longer-lived, simpler, easier to maintain) and improved maintenance. We are focusing our research on earthen caps, especially those with evapo-transpiration and capillary breaks. Typical cap assessments treat the barrier’s structure as static prior to some defined lifetime. Environmental boundary conditions such as precipitation and temperature are treated as time dependent. However, other key elements …
Date: February 1, 2003
Creator: Piet, Steven James; Jacobson, Jacob Jordan; Soto, Rafael; Martian, Pete & Martineau, Richard Charles
Object Type: Article
System: The UNT Digital Library
Making Sustainable Decisions Using the KONVERGENCE Framework (open access)

Making Sustainable Decisions Using the KONVERGENCE Framework

Hundreds of contaminated facilities and sites must be cleaned up. “Cleanup” includes decommissioning, environmental restoration, and waste management. Cleanup can be complex, expensive, risky, and time-consuming. Decisions are often controversial, can stall or be blocked, and are sometimes re-done - some before implementation, some decades later. Making and keeping decisions with long time horizons involves special difficulties and requires new approaches, including: • New ways (mental model) to analyze and visualize the problem, • Awareness of the option to shift strategy or reframe from a single decision to an adaptable network of decisions, and • Improved tactical processes that account for several challenges. These include the following: • Stakeholder values are a more fundamental basis for decision making and keeping than “meeting regulations.” • Late-entry players and future generations will question decisions. • People may resist making “irreversible” decisions. • People need “compelling reasons” to take action in the face of uncertainties. Our project goal is to make cleanup decisions easier to make, implement, keep, and sustain. By sustainability, we mean decisions that work better over the entire time-period—from when a decision is made, through implementation, to its end point. That is, alternatives that can be kept “as is” or …
Date: February 1, 2003
Creator: Piet, Steven James; Gibson, Patrick Lavern; Joe, Jeffrey Clark; Kerr, Thomas A; Nitschke, Robert Leon & Dakins, Maxine Ellen
Object Type: Article
System: The UNT Digital Library
Equilibrium in heavy ion collisions (open access)

Equilibrium in heavy ion collisions

We discuss the question of equilibration in heavy ion collisions and how it can be addressed in experiment.
Date: February 1, 2003
Creator: Koch, Volker & Majumder, Abhijit
Object Type: Article
System: The UNT Digital Library
Testing, Modeling, and Monitoring to Enable Simpler, Cheaper, Longer-Lived Surface Caps (open access)

Testing, Modeling, and Monitoring to Enable Simpler, Cheaper, Longer-Lived Surface Caps

Society has and will continue to generate hazardous wastes whose risks must be managed. For exceptionally toxic, long-lived, and feared waste, the solution is deep burial, e.g., deep geological disposal at Yucca Mtn. For some waste, recycle or destruction/treatment is possible. The alternative for other wastes is storage at or near the ground level (in someone’s back yard); most of these storage sites include a surface barrier (cap) to prevent downward water migration. Some of the hazards will persist indefinitely. As society and regulators have demanded additional proof that caps are robust against more threats and for longer time periods, the caps have become increasingly complex and expensive. As in other industries, increased complexity will eventually increase the difficulty in estimating performance, in monitoring system/component performance, and in repairing or upgrading barriers as risks are managed. An approach leading to simpler, less expensive, longer-lived, more manageable caps is needed. Our project, which started in April 2002, aims to catalyze a Barrier Improvement Cycle (iterative learning and application) and thus enable Remediation System Performance Management (doing the right maintenance neither too early nor too late). The knowledge gained and the capabilities built will help verify the adequacy of past remedial decisions, …
Date: February 1, 2003
Creator: Piet, Steven James; Breckenridge, Robert Paul & Burns, Douglas Edward
Object Type: Article
System: The UNT Digital Library
Caustic-Side Solvent Extraction: Prediction of Cesium Extraction for Actual Wastes and Actual Waste Simulants (open access)

Caustic-Side Solvent Extraction: Prediction of Cesium Extraction for Actual Wastes and Actual Waste Simulants

This report presents the work that followed the CSSX model development completed in FY2002. The developed cesium and potassium extraction model was based on extraction data obtained from simple aqueous media. It was tested to ensure the validity of the prediction for the cesium extraction from actual waste. Compositions of the actual tank waste were obtained from the Savannah River Site personnel and were used to prepare defined simulants and to predict cesium distribution ratios using the model. It was therefore possible to compare the cesium distribution ratios obtained from the actual waste, the simulant, and the predicted values. It was determined that the predicted values agree with the measured values for the simulants. Predicted values also agreed, with three exceptions, with measured values for the tank wastes. Discrepancies were attributed in part to the uncertainty in the cation/anion balance in the actual waste composition, but likely more so to the uncertainty in the potassium concentration in the waste, given the demonstrated large competing effect of this metal on cesium extraction. It was demonstrated that the upper limit for the potassium concentration in the feed ought to not exceed 0.05 M in order to maintain suitable cesium distribution ratios.
Date: February 1, 2003
Creator: Delmau, L. H.; Haverlock, T. J.; Sloop, F. V., (Jr.) & Moyer, B. A.
Object Type: Report
System: The UNT Digital Library
CO2 Sequestration and Recycle by Photosynthesis (open access)

CO2 Sequestration and Recycle by Photosynthesis

Visible light-photocatalysis could provide a cost-effective route to recycle CO{sub 2} to useful chemicals or fuels. Research is planned to study the reactivity of adsorbates, their role in the photosynthesis reaction, and their relation to the nature of surface sites during photosynthesis of methanol and hydrocarbons from CO{sub 2}/H{sub 2}O over four types of MCM-41/Al{sub 2}O{sub 3}-supported TiO{sub 2} and CdS catalysts: (1) ion-exchanged metal cations, (2) highly dispersed cations, (3) monolayer sites, and (4) modified monolayer catalysts. TiO{sub 2} was selected since it has exhibited higher activity than other oxide catalysts; CdS was selected for its photocatalytic activity in the visible light region. Al{sub 2}O{sub 3} provides excellent hydrothermal stability. MCM-41 offers high surface area (more than 800 m{sup 2}/g), providing a platform for preparing and depositing a large number of active sites per gram catalyst. The unique structure of these ion exchange cations, highly dispersed cations, and monolayer sites provides an opportunity to tailor their chemical/coordination environments for enhancing visible-light photocatalytic activity and deactivation resistance. The year one research tasks include (1) setting up experimental system, (2) preparing ion-exchanged metal cations, highly dispersed cations, monolayer sites of TiO{sub 2} and CdS, and (3) determination of the dependence of …
Date: February 1, 2003
Creator: Chuang, Steven S.C.
Object Type: Report
System: The UNT Digital Library
'Mini'-Roadmapping - Ensuring Timely Sites' Cleanup / Closure by Resolving Science and Technology Issues (open access)

'Mini'-Roadmapping - Ensuring Timely Sites' Cleanup / Closure by Resolving Science and Technology Issues

Roadmapping is a powerful tool to manage technical risks and opportunities associated with complex problems. Roadmapping identifies technical capabilities required for both project- and program-level efforts and provides the basis for plans that ensure the necessary enabling activities will be done when needed. Roadmapping reveals where to focus further development of the path forward by evaluating uncertainties for levels of complexity, impacts, and/or the potential for large payback. Roadmaps can be customized to the application, a “graded approach” if you will. Some roadmaps are less detailed. We have called these less detailed, top-level roadmaps “mini-roadmaps”. These miniroadmaps are created to tie the needed enablers (e.g., technologies, decisions, etc.) to the functions. If it is found during the mini-roadmapping that areas of significant risk exist, then those can be roadmapped further to a lower level of detail. Otherwise, the mini-roadmap may be sufficient to manage the project / program risk. Applying a graded approach to the roadmapping can help keep the costs down. Experience has indicated that it is best to do mini-roadmapping first and then evaluate the risky areas to determine whether to further evaluate those areas. Roadmapping can be especially useful for programs / projects that have participants from …
Date: February 1, 2003
Creator: Luke, Dale & Murphy, James
Object Type: Article
System: The UNT Digital Library
NOx Solutions for Biodiesel: Final Report; Report 6 in a Series of 6 (open access)

NOx Solutions for Biodiesel: Final Report; Report 6 in a Series of 6

A number of studies have shown substantial particulate matter (PM) reductions for biodiesel, but also a significant increase in nitrogen oxides (NOx) emissions. This study examines a number of approaches for NOx reduction from biodiesel.
Date: February 1, 2003
Creator: McCormick, R. L.; Alvarez, J. R. & Graboski, M. S.
Object Type: Report
System: The UNT Digital Library
Reconnaissance of Field Sites for the Study of Chemical Weathering on the Guayana Shield, South America (open access)

Reconnaissance of Field Sites for the Study of Chemical Weathering on the Guayana Shield, South America

Despite the fact that chemical weathering of silicate rocks plays an important role in the draw-down of CO{sub 2} over geologic time scales (Berner and Berner, 1996), the overall controls on the rate of chemical weathering are still not completely understood. Lacking a mechanistic understanding of these controls, it remains difficult to evaluate a hypothesis such as that presented by Raymo and Ruddiman (1992), who suggested that enhanced weathering and CO{sub 2} draw-down resulting from the uplift of the Himalayas contributed to global cooling during the Cenozoic. At an even more fundamental level, the three to four order of magnitude discrepancy between laboratory and field weathering rates is still unresolved (White et al., 1996). There is as yet no comprehensive, mechanistic model for silicate chemical weathering that considers the coupled effects of precipitation, vadose zone flow, and chemical reactions. The absence of robust process models for silicate weathering and the failure to resolve some of these important questions may in fact be related-the controls on the overall rates of weathering cannot be understood without considering the weathering environment as one in which multiple, time-dependent chemical and physical processes are coupled (Malmstrom, 2000). Once chemical weathering is understood at a mechanistic …
Date: February 1, 2003
Creator: Steefell, C. I.; Viani, B. E.; Ramirez, A. & Lee, K.
Object Type: Report
System: The UNT Digital Library
12th Workshop on Crystalline Silicon Solar Cell Materials and Processes: Summary Discussion Sessions (open access)

12th Workshop on Crystalline Silicon Solar Cell Materials and Processes: Summary Discussion Sessions

This report is a summary of the discussion sessions of the 12th Workshop on Crystalline Silicon Solar Cells and Processes. The theme of the workshop was"Fundamental R&D in c-Si: Enabling Progress in Solar-Electric Technology." This theme was chosen to reflect a concern that the current expansion in the PV energy production may redirect basic research efforts to production-oriented issues. The PV industry is installing added production capacity and new production lines that include the latest technologies. Once the technologies are selected, it is difficult to make changes. Consequently, a large expansion can stagnate the technologies and diminish interest in fundamental research. To prevent the fundamental R&D program from being overwhelmed by the desire to address immediate engineering issues, there is a need to establish topics of fundamental nature that can be pursued by the universities and the research institutions. Hence, one of the objectives of the workshop was to identify such areas for fundamental research.
Date: February 1, 2003
Creator: Sopori, B.; Swanson, D.; Sinton, R. & Tan, T.
Object Type: Article
System: The UNT Digital Library
Assessing the Potential for Renewable Energy on Public Lands (open access)

Assessing the Potential for Renewable Energy on Public Lands

This report represents an initial activity of the Bureau of Land Managements (BLM) proposed National Energy Policy Implementation Plan: identify and evaluate renewable energy resources on federal lands and any limitations on accessing them. Ultimately, BLM will prioritize land-use planning activities to increase industrys development of renewable energy resources. These resources include solar, biomass, geothermal, water, and wind energy. To accomplish this, BLM and the Department of Energys National Renewable Energy Laboratory (NREL) established a partnership to conduct an assessment of renewable energy resources on BLM lands in the western United States. The objective of this collaboration was to identify BLM planning units in the western states with the highest potential for private-sector development of renewable resources. The assessment resulted in the following findings: (1) 63 BLM planning units in nine western states have high potential for one or more renewable energy technologies; and (2) 20 BLM planning units in seven western states have high potential for power production from three or more renewable energy sources. This assessment report provides BLM with information needed to prioritize land-use planning activities on the basis of potential for the development of energy from renewable resources.
Date: February 1, 2003
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Luminosity Increase at the Incoherent Beam-Beam Limit in RHIC (open access)

Luminosity Increase at the Incoherent Beam-Beam Limit in RHIC

N/A
Date: February 1, 2003
Creator: Fischer, W. & Blaskiewicz, M.
Object Type: Report
System: The UNT Digital Library
Evaluation of Fish Movements, Migration Patterns, and Population Abundance with Streamwidth PIT Tag Interrogation Systems, Final Report 2002. (open access)

Evaluation of Fish Movements, Migration Patterns, and Population Abundance with Streamwidth PIT Tag Interrogation Systems, Final Report 2002.

Two remote Streamwidth PIT tag Interrogation systems (SPIs) were operated continuously for over one year to test the feasibility of these systems for generating movement, migration, survival and smolt production estimates for salmonids. A total of 1,588 juvenile (< 100 mm FL) naturally produced salmonids (7 coho salmon, 482 cutthroat trout, and 1,099 steelhead) were PIT tagged above the upstream-most SPI (9 sites approximately 1 linear km each) in Fall 2001. Age at tagging for wild caught cutthroat and steelhead was 1 year. SPIs were operating before any PIT tagged fish were released in the creek. Over 390,000 detections were recorded from October 2001 to 31 July 2002. Efficiencies were site dependent, but overall detection efficiency for the creek was 97% with 95% confidence intervals of 91-100%. PIT tag detection efficiency ranged from 55-100% depending on the SPI and varied throughout the year with average efficiencies of 73% and 89%. SPI efficiency of PIT tag detection was not completely dependent on electronics noise levels or environmental conditions. Fish from all tagging locations were detected at the SPIs. Steelhead and cutthroat trout were primarily detected moving in the Spring (April-June) coincident with the anticipated smolt migration. Steelhead were also detected moving …
Date: February 1, 2003
Creator: Zydlewski, Gayle; Winter, Christiane & McClanahan, Dee
Object Type: Report
System: The UNT Digital Library
Spawning Distribution of Fall Chinook Salmon in the Snake River, Annual Report 2001-2002. (open access)

Spawning Distribution of Fall Chinook Salmon in the Snake River, Annual Report 2001-2002.

None
Date: February 1, 2003
Creator: Garcia, Aaron P.
Object Type: Report
System: The UNT Digital Library
Walla Walla River Basin Screening, Annual Report 2002. (open access)

Walla Walla River Basin Screening, Annual Report 2002.

In order to meet the need for protective fish screening, the Walla Walla County Conservation District (WWCCD) and the Washington Department of Fish and Wildlife (WDFW) formed a partnership to implement the WDFW Cooperative Compliance Review and Cost-Share Program. The program provides technical and financial assistance to irrigators in order to bring existing surface water diversions into compliance with state and federal juvenile fish screen criteria. The Walla Walla basin has two priority salmonid species currently listed as threatened under the Endangered Species Act, the Bull Trout and Mid-Columbia Basin Steelhead. Other partners in this effort include the Washington Department of Ecology, National Marine Fisheries Service, US Fish and Wildlife Service, and the Walla Walla Community College Irrigation Department. A Screening Oversight Committee of representatives from these agencies sets policy and resolves issues.
Date: February 1, 2003
Creator: Ahmann, Audrey & Jones, Rick
Object Type: Report
System: The UNT Digital Library
Contamination Control During In Situ Jet Grouting for Application in a Buried Transuranic Waste Site (open access)

Contamination Control During In Situ Jet Grouting for Application in a Buried Transuranic Waste Site

Engineers at the Idaho National Engineering and Environmental Laboratory (INEEL) have developed means of contamination control associated with jet-grouting buried radioactive mixed waste sites. Finely divided plutonium/americium oxide particulate can escape as the drill stem of the jet-grouting apparatus exits a waste deposit in preparation for insertion in another injection hole. In studying various options for controlling this potential contamination, engineers found that an elaborate glovebox/drill string shroud system prevents contaminants from spreading. Researchers jet-grouted a pit with nonradioactive tracers to simulate the movement of plutonium fines during an actual application. Data from the testing indicate that the grout immobilizes the tracer material by locking it up in particles large enough to resist aerosolization.
Date: February 1, 2003
Creator: Loomis, Guy George & Jessmore, James Joseph
Object Type: Article
System: The UNT Digital Library
2002 Wastewater Land Application Site Performance Reports for the Idaho National Engineering and Environmental Laboratory and Associated Documentation (open access)

2002 Wastewater Land Application Site Performance Reports for the Idaho National Engineering and Environmental Laboratory and Associated Documentation

The 2002 Wastewater Land Application site Performance Reports for the Idaho National Engineering and Environmental Laboratory describe site conditions for the facilities with State of Idaho Wastewater Land Application Permits. Permit-required monitoring data are summarized, and permit exceedences or environmental impacts relating to the operation of the facilities during the 2002 permit year are discussed.
Date: February 1, 2003
Creator: Meachum, Teresa Ray & Lewis, Michael G.
Object Type: Report
System: The UNT Digital Library
Evaluation of Calcine Disposition - Path Forward (open access)

Evaluation of Calcine Disposition - Path Forward

This document describes an evaluation of the baseline and two alternative disposition paths for the final disposition of the calcine wastes stored at the Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory. The pathways are evaluated against a prescribed set of criteria and a recommendation is made for the path forward.
Date: February 1, 2003
Creator: Birrer, Steve
Object Type: Report
System: The UNT Digital Library
U.S. DOE FreedomCAR and Vehicle Technologies Advanced Technology Development Program for Lithium-Ion Batteries: Gen 2 Performance Evaluation Interim Report (open access)

U.S. DOE FreedomCAR and Vehicle Technologies Advanced Technology Development Program for Lithium-Ion Batteries: Gen 2 Performance Evaluation Interim Report

The Advanced Technology Development Program is currently evaluating the performance of the second generation of Lithium-ion cells (i.e., Gen 2 cells). The 18650-size Gen 2 cells consist of a baseline chemistry and one variant chemistry. These cells were distributed over a matrix consisting of three states-of-charge (SOC) (60, 80, and 100% SOC), four temperatures (25, 35, 45, and 55°C), and three life tests (calendar-, cycle-, and accelerated-life). The calendar-life cells are clamped at an opencircuit voltage corresponding to 60% SOC and undergo a once-per-day pulse profile. The cycle-life cells are continuously pulsed using a profile that is centered around 60% SOC. The accelerated-life cells are following the calendar-life test procedures, but using the cycle-life pulse profile. Life testing is interrupted every four weeks for reference performance tests (RPTs), which are used to quantify changes in capacity, resistance, and power. The RPTs consist of a C1/1 and C1/25 static capacity tests, a low-current hybrid pulse power characterization test, and electrochemical impedance spectroscopy at 60% SOC. Capacity-, power-, and electrochemical impedance spectroscopy-based performance results are reported.
Date: February 1, 2003
Creator: Christophersen, Jon P.; Motloch, Chet; Bloom, Ira D.; Battaglia, Vince; Nagasubramanian, Ganesan & Duong, Tien Q.
Object Type: Report
System: The UNT Digital Library
Hydrogen Gas Generation Model for Fuel Based Remote Handled TRU Waste Stored at INEEL (open access)

Hydrogen Gas Generation Model for Fuel Based Remote Handled TRU Waste Stored at INEEL

The Idaho National Environmental and Engineering Laboratory (INEEL) initiated efforts to calculate the hydrogen gas generation in remote-handled transuranic (RH-TRU) containers in order to evaluate continued storage of unvented RH-TRU containers in vaults and to identify any potential problems during retrieval and aboveground storage. A computer code is developed to calculate the hydrogen concentration in the stored RH-TRU waste drums for known configuration, waste matrix, and radionuclide inventories as a function of time.
Date: February 1, 2003
Creator: Khericha, Soli T.; Bhatt, Rajiv N. & Liekhus, Kevin
Object Type: Article
System: The UNT Digital Library
Verification, validation, and predictive capability in computational engineering and physics. (open access)

Verification, validation, and predictive capability in computational engineering and physics.

Developers of computer codes, analysts who use the codes, and decision makers who rely on the results of the analyses face a critical question: How should confidence in modeling and simulation be critically assessed? Verification and validation (V&V) of computational simulations are the primary methods for building and quantifying this confidence. Briefly, verification is the assessment of the accuracy of the solution to a computational model. Validation is the assessment of the accuracy of a computational simulation by comparison with experimental data. In verification, the relationship of the simulation to the real world is not an issue. In validation, the relationship between computation and the real world, i.e., experimental data, is the issue.
Date: February 1, 2003
Creator: Oberkampf, William Louis; Hirsch, Charles (Vrije Universiteit Brussel, Brussels, Belgium) & Trucano, Timothy Guy
Object Type: Report
System: The UNT Digital Library
Radiological Characterization Methodology of INEEL Stored RH-TRU Waste from ANL-E (open access)

Radiological Characterization Methodology of INEEL Stored RH-TRU Waste from ANL-E

An Acceptable Knowledge (AK)-based radiological characterization methodology is being developed for RH TRU waste generated from ANL-E hot cell operations performed on fuel elements irradiated in the EBR-II reactor. The methodology relies on AK for composition of the fresh fuel elements, their irradiation history, and the waste generation and collection processes. Radiological characterization of the waste involves the estimates of the quantities of significant fission products and transuranic isotopes in the waste. Methods based on reactor and physics principles are used to achieve these estimates. Because of the availability of AK and the robustness of the calculation methods, the AK-based characterization methodology offers a superior alternative to traditional waste assay techniques. Using this methodology, it is shown that the radiological parameters of a test batch of ANL-E waste is well within the proposed WIPP Waste Acceptance Criteria limits.
Date: February 1, 2003
Creator: Bhatt, Rajiv N.
Object Type: Article
System: The UNT Digital Library

Current TES Capabilities in TRNSYS

This presentation includes: a brief overview of TRNSYS, a review of current SolarPaces models, potential of other models appropriate for CSP TES, and a review of a project proposal.
Date: February 1, 2003
Creator: Price, H. & Blair, N.
Object Type: Presentation
System: The UNT Digital Library
Neptunium Valence Chemistry in Anion Exchange Processing (open access)

Neptunium Valence Chemistry in Anion Exchange Processing

The current anion resin in use in HB-Line Phase II, Reillex{trademark} HPQ, was tested in the laboratory under expected plant conditions for Np processing and was found to load between 50 and 70 g Np per liter of resin. Losses varied from 0.2 to 15 percent depending on a number of parameters. Hydrazine in the feed at 0.02 to 0.05 M appeared to keep the Np from oxidizing and increasing the losses within four to seven days after the FS addition. Losses of up to three percent were observed five days after FS addition when hydrazine was not used in the feed, compared with 0.3 percent when the feed was loaded immediately after FS addition. Based on these test results the following processing conditions are recommended: (1) Feed conditions: 8 M HNO{sub 3}, 0.02 M hydrazine, 0.05 M excess FS, less than 5 days storage of solution after FS addition. (2) Wash conditions: 100 liters of 8 M HNO{sub 3}, no FS, no hydrazine. (3) Elution conditions: 0.17 M HNO{sub 3}, 0.05 M hydrazine, no FS. (4) Precipitation feed conditions: 0.03 M excess ascorbic acid, no additional hydrazine, no FS, precipitation within three days.
Date: February 1, 2003
Creator: Kyser, Edward
Object Type: Report
System: The UNT Digital Library