Solid-State Fault Current Limiter Development : Design and Testing Update of a 15kV SSCL Power Stack (open access)

Solid-State Fault Current Limiter Development : Design and Testing Update of a 15kV SSCL Power Stack

ABSTRACT The Solid-State Fault Current Limiter (SSCL) is a promising technology that can be applied to utility power delivery systems to address the problem of increasing fault currents associated with load growth. As demand continues to grow, more power is added to utility system either by increasing generator capacity or by adding distributed generators, resulting in higher available fault currents, often beyond the capabilities of the present infrastructure. The SSCL is power-electronics based equipment designed to work with the present utility system to address this problem. The SSCL monitors the line current and dynamically inserts additional impedance into the line in the event of a fault being detected. The SSCL is based on a modular design and can be configured for 5kV through 69kV systems at nominal current ratings of 1000A to 4000A. Results and Findings This report provides the final test results on the development of 15kV class SSCL single phase power stack. The scope of work included the design of the modular standard building block sub-assemblies, the design and manufacture of the power stack and the testing of the power stack for the key functional tests of continuous current capability and fault current limiting action. Challenges and Objectives …
Date: April 30, 2012
Creator: Adapa, Dr. Ram & Piccone, Mr. Dante
Object Type: Report
System: The UNT Digital Library
Efficient and Scalable Retrieval Techniques for Global File Properties (open access)

Efficient and Scalable Retrieval Techniques for Global File Properties

None
Date: April 30, 2012
Creator: Ahn, D H; Brim, M; de Supinski, B R; Gamblin, T; Lee, G L; LeGendre, M P et al.
Object Type: Article
System: The UNT Digital Library
Water-related Issues Affecting Conventional Oil and Gas Recovery and Potential Oil-Shale Development in the Uinta Basin, Utah (open access)

Water-related Issues Affecting Conventional Oil and Gas Recovery and Potential Oil-Shale Development in the Uinta Basin, Utah

Saline water disposal is one of the most pressing issues with regard to increasing petroleum and natural gas production in the Uinta Basin of northeastern Utah. Conventional oil fields in the basin provide 69 percent of Utah?s total crude oil production and 71 percent of Utah?s total natural gas, the latter of which has increased 208% in the past 10 years. Along with hydrocarbons, wells in the Uinta Basin produce significant quantities of saline water ? nearly 4 million barrels of saline water per month in Uintah County and nearly 2 million barrels per month in Duchesne County. As hydrocarbon production increases, so does saline water production, creating an increased need for economic and environmentally responsible disposal plans. Current water disposal wells are near capacity, and permitting for new wells is being delayed because of a lack of technical data regarding potential disposal aquifers and questions concerning contamination of freshwater sources. Many companies are reluctantly resorting to evaporation ponds as a short-term solution, but these ponds have limited capacity, are prone to leakage, and pose potential risks to birds and other wildlife. Many Uinta Basin operators claim that oil and natural gas production cannot reach its full potential until a …
Date: April 30, 2012
Creator: Berg, Michael Vanden; Anderson, Paul; Wallace, Janae; Morgan, Craig & Carney, Stephanie
Object Type: Report
System: The UNT Digital Library
Technology to Facilitate the Use of Impaired Waters in Cooling Towers (open access)

Technology to Facilitate the Use of Impaired Waters in Cooling Towers

The project goal was to develop an effective silica removal technology and couple that with existing electro-dialysis reversal (EDR) technology to achieve a cost effective treatment for impaired waters to allow for their use in the cooling towers of coal fired power plants. A quantitative target of the program was a 50% reduction in the fresh water withdrawal at a levelized cost of water of $3.90/Kgal. Over the course of the program, a new molybdenum-modified alumina was developed that significantly outperforms existing alumina materials in silica removal both kinetically and thermodynamically. The Langmuir capacity is 0.11g silica/g adsorbent. Moreover, a low cost recycle/regeneration process was discovered to allow for multiple recycles with minimal loss in activity. On the lab scale, five runs were carried out with no drop in performance between the second and fifth run in ability to absorb the silica from water. The Mo-modified alumina was successfully prepared on a multiple kilogram scale and a bench scale model column was used to remove 100 ppm of silica from 400 liters of simulated impaired water. Significant water savings would result from such a process and the regeneration process could be further optimized to reduce water requirements. Current barriers to …
Date: April 30, 2012
Creator: Colborn, Robert
Object Type: Report
System: The UNT Digital Library
Final Report for Department of Energy/EERE (for public release) (open access)

Final Report for Department of Energy/EERE (for public release)

Developing CIGS solar cells calls for the understanding of materials and processing in order to translate the record small efficiency to module and the strategy to produce thin cells for materials and processing saving. This project has exploited nanostructuring of CIG solar cells, including nanowires and nanotextured substrates. We showed that nanowires function as well-defined CIGS-CdS p-n junction for understanding the chemical fluctuation, defect formation interface and grain boundary behaviors and the effect of ion diffusion, which are important but complicated issues for solar cell fabrication. We have also demonstrated effective nanoscale photon management on nanotextured substrate to provide opportunity for thin CIGS solar cells. We also developed the scalable methods for producing such nanotextured substrates. The research output in this project helps advancing the CIGS solar cells and broadly other solar cell technologies in cost reduction per unit power.
Date: April 30, 2012
Creator: Cui, Yi
Object Type: Report
System: The UNT Digital Library
Carbon Capture and Sequestration: A Regulatory Gap Assessment (open access)

Carbon Capture and Sequestration: A Regulatory Gap Assessment

Though a potentially significant climate change mitigation strategy, carbon capture and sequestration (CCS) remains mired in demonstration and development rather than proceeding to full-scale commercialization. Prior studies have suggested numerous reasons for this stagnation. This Report seeks to empirically assess those claims. Using an anonymous opinion survey completed by over 200 individuals involved in CCS, it concludes that there are four primary barriers to CCS commercialization: (1) cost, (2) lack of a carbon price, (3) liability risks, and (4) lack of a comprehensive regulatory regime. These results largely confirm previous work. They also, however, expose a key barrier that prior studies have overlooked: the need for comprehensive, rather than piecemeal, CCS regulation. The survey data clearly show that the CCS community sees this as one of the most needed incentives for CCS deployment. The community also has a relatively clear idea of what that regulation should entail: a cooperative federalism approach that directly addresses liability concerns and that generally does not upset traditional lines of federal-state authority.
Date: April 30, 2012
Creator: Davies, Lincoln; Uchitel, Kirsten; Ruple, John & Tanana, Heather
Object Type: Report
System: The UNT Digital Library
Carbon Capture and Sequestration: A Regulatory Gap Assessment (open access)

Carbon Capture and Sequestration: A Regulatory Gap Assessment

Though a potentially significant climate change mitigation strategy, carbon capture and sequestration (CCS) remains mired in demonstration and development rather than proceeding to full-scale commercialization. Prior studies have suggested numerous reasons for this stagnation. This Report seeks to empirically assess those claims. Using an anonymous opinion survey completed by over 200 individuals involved in CCS, it concludes that there are four primary barriers to CCS commercialization: (1) cost, (2) lack of a carbon price, (3) liability risks, and (4) lack of a comprehensive regulatory regime. These results largely confirm previous work. They also, however, expose a key barrier that prior studies have overlooked: the need for comprehensive, rather than piecemeal, CCS regulation. The survey data clearly show that the CCS community sees this as one of the most needed incentives for CCS deployment. The community also has a relatively clear idea of what that regulation should entail: a cooperative federalism approach that directly addresses liability concerns and that generally does not upset traditional lines of federal-state authority.
Date: April 30, 2012
Creator: Davies, Lincoln; Uchitel, Kirsten; Ruple, John & Tanana, Heather
Object Type: Report
System: The UNT Digital Library
High Flux Commercial Illumination Solution with Intelligent Controls (open access)

High Flux Commercial Illumination Solution with Intelligent Controls

This report summarizes the work performed at OSRAM SYLVANIA under US Department of Energy contract DE-EE0003241 for developing a high efficiency LED-based luminaire. A novel light engine module (two versions: standard and super), power supply and luminaire mechanical parts were designed and tested. At steady-state, the luminaire luminous flux is 3156 lumens (lm), luminous efficacy 97.4 LPW and CRI (Ra) 88 at a correlated color temperature (CCT) of 3507K. When the luminaire is fitted with the super version of the light engine the efficacy reaches 130 LPW. In addition, the luminaire is provided with an intelligent control network capable of additional energy savings. The technology developed during the course of this project has been incorporated into a family of products. Recently, the first product in the family has been launched.
Date: April 30, 2012
Creator: Ghiu, Camil
Object Type: Report
System: The UNT Digital Library
Improvement of capabilities of the Distributed Electrochemistry Modeling Tool for investigating SOFC long term performance (open access)

Improvement of capabilities of the Distributed Electrochemistry Modeling Tool for investigating SOFC long term performance

This report provides an overview of the work performed for Solid Oxide Fuel Cell (SOFC) modeling during the 2012 Winter/Spring Science Undergraduate Laboratory Internship at Pacific Northwest National Laboratory (PNNL). A brief introduction on the concept, operation basics and applications of fuel cells is given for the general audience. Further details are given regarding the modifications and improvements of the Distributed Electrochemistry (DEC) Modeling tool developed by PNNL engineers to model SOFC long term performance. Within this analysis, a literature review on anode degradation mechanisms is explained and future plans of implementing these into the DEC modeling tool are also proposed.
Date: April 30, 2012
Creator: Gonzalez Galdamez, Rinaldo A. & Recknagle, Kurtis P.
Object Type: Report
System: The UNT Digital Library
Advanced Production Surface Preparation Technology Development for Ultra-High Pressure Diesel Injection (open access)

Advanced Production Surface Preparation Technology Development for Ultra-High Pressure Diesel Injection

In 2007, An Ultra High Injection Pressure (UHIP) fueling method has been demonstrated by Caterpillar Fuel Systems - Product Development, demonstrating ability to deliver U.S. Environment Protection Agency (EPA) Tier 4 Final diesel engine emission performance with greatly reduced emissions handling components on the engine, such as without NOx reduction after-treatment and with only a through-flow 50% effective diesel particulate trap (DPT). They have shown this capability using multiple multi-cylinder engine tests of an Ultra High Pressure Common Rail (UHPCR) fuel system with higher than traditional levels of CEGR and an advanced injector nozzle design. The system delivered better atomization of the fuel, for more complete burn, to greatly reduce diesel particulates, while CEGR or high efficiency NOx reduction after-treatment handles the NOx. With the reduced back pressure of a traditional DPT, and with the more complete fuel burn, the system reduced levels of fuel consumption by 2.4% for similar delivery of torque and horsepower over the best Tier 4 Interim levels of fuel consumption in the diesel power industry. The challenge is to manufacture the components in high-volume production that can withstand the required higher pressure injection. Production processes must be developed to increase the toughness of the injector …
Date: April 30, 2012
Creator: Grant, Marion B.
Object Type: Report
System: The UNT Digital Library
Building Diagnostic Market Deployment - Final Report (open access)

Building Diagnostic Market Deployment - Final Report

Operational faults are pervasive across the commercial buildings sector, wasting energy and increasing energy costs by up to about 30% (Mills 2009, Liu et al. 2003, Claridge et al. 2000, Katipamula and Brambley 2008, and Brambley and Katipamula 2009). Automated fault detection and diagnostic (AFDD) tools provide capabilities essential for detecting and correcting these problems and eliminating the associated energy waste and costs. The U.S. Department of Energy's (DOE) Building Technology Program (BTP) has previously invested in developing and testing of such diagnostic tools for whole-building (and major system) energy use, air handlers, chillers, cooling towers, chilled-water distribution systems, and boilers. These diagnostic processes can be used to make the commercial buildings more energy efficient. The work described in this report was done as part of a Cooperative Research and Development Agreement (CRADA) between the U.S. Department of Energy's Pacific Northwest National Laboratory (PNNL) and KGS Building LLC (KGS). PNNL and KGS both believe that the widespread adoption of AFDD tools will result in significant reduction to energy and peak energy consumption. The report provides an introduction and summary of the various tasks performed under the CRADA. The CRADA project had three major focus areas: (1) Technical Assistance for Whole …
Date: April 30, 2012
Creator: Katipamula, S. & Gayeski, N.
Object Type: Report
System: The UNT Digital Library
Reuse of Produced Water from CO2 Enhanced Oil Recovery, Coal-Bed Methane, and Mine Pool Water by Coal-Based Power Plants (open access)

Reuse of Produced Water from CO2 Enhanced Oil Recovery, Coal-Bed Methane, and Mine Pool Water by Coal-Based Power Plants

Power generation in the Illinois Basin is expected to increase by as much as 30% by the year 2030, and this would increase the cooling water consumption in the region by approximately 40%. This project investigated the potential use of produced water from CO{sub 2} enhanced oil recovery (CO{sub 2}-EOR) operations; coal-bed methane (CBM) recovery; and active and abandoned underground coal mines for power plant cooling in the Illinois Basin. Specific objectives of this project were: (1) to characterize the quantity, quality, and geographic distribution of produced water in the Illinois Basin; (2) to evaluate treatment options so that produced water may be used beneficially at power plants; and (3) to perform a techno-economic analysis of the treatment and transportation of produced water to thermoelectric power plants in the Illinois Basin. Current produced water availability within the basin is not large, but potential flow rates up to 257 million liters per day (68 million gallons per day (MGD)) are possible if CO{sub 2}-enhanced oil recovery and coal bed methane recovery are implemented on a large scale. Produced water samples taken during the project tend to have dissolved solids concentrations between 10 and 100 g/L, and water from coal beds tends …
Date: April 30, 2012
Creator: Knutson, Chad; Dastgheib, Seyed; Yang, Yaning; Ashraf, Ali; Duckworth, Cole; Sinata, Priscilla et al.
Object Type: Report
System: The UNT Digital Library
Post-Retrofit Residential Assessments (open access)

Post-Retrofit Residential Assessments

This study examined a range of factors influencing energy consumption in households that had participated in residential energy-efficiency upgrades. The study was funded by a grant from the U.S. Department of Energy’s Pacific Northwest National Laboratory and was conducted by faculty and staff of Portland State University Center for Urban Studies and Department of Economics. This work was made possible through the assistance and support of the Energy Trust of Oregon (ETO), whose residential energy-efficiency programs provided the population from which the sample cases were drawn. All households in the study had participated in the ETO Home Performance with Energy Star (HPwES) program. A number of these had concurrently pursued measures through other ETO programs. Post-retrofit energy outcomes are rarely investigated on a house-by-house basis. Rather, aggregate changes are ordinarily the focus of program impact evaluations, with deviation from aggregate expectations chalked up to measurement error, the vagaries of weather and idiosyncrasies of occupants. However, understanding how homes perform post-retrofit on an individual basis can give important insights to increase energy savings at the participant and the programmatic level. Taking a more disaggregated approach, this study analyzed energy consumption data from before and after the retrofit activity and made comparisons …
Date: April 30, 2012
Creator: Lancaster, Ross; Lutzenhiser, Loren; Moezzi, Mithra; Widder, Sarah H.; Chandra, Subrato & Baechler, Michael C.
Object Type: Report
System: The UNT Digital Library
Development and Evaluation of a Novel Integrated Vacuum Carbonate Absorption Process (open access)

Development and Evaluation of a Novel Integrated Vacuum Carbonate Absorption Process

This project was aimed at obtaining process engineering and scale-up data at a laboratory scale to investigate the technical and economic feasibility of a patented post-combustion carbon dioxide (CO{sub 2}) capture process?the Integrated Vacuum Carbonate Absorption Process (IVCAP). Unique features of the IVCAP include its ability to be fully-integrated with the power plant?s steam cycle and potential for combined sulfur dioxide (SO{sub 2}) removal and CO{sub 2} capture. Theoretical and experimental studies of this project were aimed at answering three major technical questions: 1) What additives can effectively reduce the water vapor saturation pressure and energy requirement for water vaporization in the vacuum stripper of the IVCAP? 2) What catalysts can promote CO{sub 2} absorption into the potassium carbonate (PC) solution to achieve an overall absorption rate comparable to monoethanolamine (MEA) and are the catalysts stable at the IVCAP conditions and in the flue gas environment? 3) Are any process modifications needed to combine SO{sub 2} and CO{sub 2} removal in the IVCAP? Lab-scale experiments and thermodynamic and process simulation studies performed to obtain detailed information pertinent to the above three technical questions produced the following results: 1) Two additives were identified that lower the saturation pressure of water vapor …
Date: April 30, 2012
Creator: Lu, Yongqi; Rostam-Abadi, Massoud; Ye, Xinhuai; Zhang, Shihan; Ruhter, David; Khodayari, Arezoo et al.
Object Type: Report
System: The UNT Digital Library
Final Technical Report: Supporting Wind Turbine Research and Testing - Gearbox Durability Study (open access)

Final Technical Report: Supporting Wind Turbine Research and Testing - Gearbox Durability Study

The combination of premature failure of wind turbine gearboxes and the downtime caused by those failures leads to an increase in the cost of electricity produced by the wind. There is a need for guidance to asset managers regarding how to maximize the longevity of their gearboxes in order to help keep the cost of wind energy as low as possible. A low cost of energy supports the US Department of Energy's goal of achieving 20% of the electricity in the United States produced by wind by the year 2030. DNV KEMA has leveraged our unique position in the industry as an independent third party engineering organization to study the problem of gearbox health management and develop guidance to project operators. This report describes the study. The study was conducted in four tasks. In Task 1, data that may be related to gearbox health and are normally available to wind project operators were collected for analysis. Task 2 took a more in-depth look at a small number of gearboxes to gain insight in to relevant failure modes. Task 3 brought together the previous tasks by evaluating the available data in an effort to identify data that could provide early indications …
Date: April 30, 2012
Creator: Malkin, Matthew
Object Type: Report
System: The UNT Digital Library
Ceramic HEPA Filter Program (open access)

Ceramic HEPA Filter Program

Potential benefits of ceramic filters in nuclear facilities: (1) Short term benefit for DOE, NRC, and industry - (a) CalPoly HTTU provides unique testing capability to answer questions for DOE - High temperature testing of materials, components, filter, (b) Several DNFSB correspondences and presentations by DNFSB members have highlighted the need for HEPA filter R and D - DNFSB Recommendation 2009-2 highlighted a nuclear facility response to an evaluation basis earthquake followed by a fire (aka shake-n-bake) and CalPoly has capability for a shake-n-bake test; (2) Intermediate term benefit for DOE and industry - (a) Filtration for specialty applications, e.g., explosive applications at Nevada, (b) Spin-off technologies applicable to other commercial industries; and (3) Long term benefit for DOE, NRC, and industry - (a) Across industry, strong desire for better performance filter, (b) Engineering solution to safety problem will improve facility safety and decrease dependence on associated support systems, (c) Large potential life-cycle cost savings, and (d) Facilitates development and deployment of LLNL process innovations to allow continuous ventilation system operation during a fire.
Date: April 30, 2012
Creator: Mitchell, M A; Bergman, W; Haslam, J; Brown, E P; Sawyer, S; Beaulieu, R et al.
Object Type: Article
System: The UNT Digital Library
China's Rare Earth Industry and Export Regime: Economic and Trade Implications for the United States (open access)

China's Rare Earth Industry and Export Regime: Economic and Trade Implications for the United States

Over the past few years, the Chinese government has implemented a number of policies to tighten its control over the production and export of "rare earths"-a unique group of 17 metal elements on the periodic table that exhibit a range of special properties, such as magnetism, luminescence, and strength. Rare earths are important to a number of high technology industries, including renewable energy and various defense systems. This report examines the economic and trade implications of China's rare earth policies for the United States.
Date: April 30, 2012
Creator: Morrison, Wayne M. & Tang, Rachel
Object Type: Report
System: The UNT Digital Library
DIXI (Dilation x-ray imager) a new/faster gated x-ray imager for the NIF (open access)

DIXI (Dilation x-ray imager) a new/faster gated x-ray imager for the NIF

None
Date: April 30, 2012
Creator: Nagel, S. R.; Hilsabeck, T. J.; Bell, P. M.; Bradley, D. K.; Ayers, M. J.; Barrios, M. A. et al.
Object Type: Article
System: The UNT Digital Library
Closure Report for Corrective Action Unit 574: Neptune, Nevada National Security Site, Nevada (open access)

Closure Report for Corrective Action Unit 574: Neptune, Nevada National Security Site, Nevada

Corrective Action Unit (CAU) 574 is identified in the Federal Facility Agreement and Consent Order (FFACO) as 'Neptune' and consists of the following two Corrective Action Sites (CASs), located in Area 12 of the Nevada National Security Site: (1) CAS 12-23-10, U12c.03 Crater (Neptune); and (2) CAS 12-45-01, U12e.05 Crater (Blanca). This Closure Report presents information supporting closure of CAU 574 according to the FFACO (FFACO, 1996 [as amended March 2010]) and the Streamlined Approach for Environmental Restoration Plan for CAU 574 (U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office [NNSA/NSO], 2011). The following activities were performed to support closure of CAU 574: (1) In situ external dose rate measurements were collected using thermoluminescent dosimeters at CAS 12-45-01, U12e.05 Crater (Blanca). (2) Total effective dose rates were determined at both sites by summing the internal and external dose rate components. (3) A use restriction (UR) was implemented at CAS 12-23-10, U12c.03 Crater (Neptune). Areas that exceed the final action level (FAL) of 25 millirems per year (mrem/yr) based on the Occasional Use Area exposure scenario are within the existing use restricted area for CAU 551. The 25-mrem/yr FAL is not exceeded outside the existing CAU 551 UR …
Date: April 30, 2012
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
An arbuscular mycorrhizal fungus modifies the soil microbial community and nitrogen cycling during litter decomposition (open access)

An arbuscular mycorrhizal fungus modifies the soil microbial community and nitrogen cycling during litter decomposition

None
Date: April 30, 2012
Creator: Nuccio, E E; Hodge, A; Pett-Ridge, J; Herman, D J; Weber, P & Firestone, M K
Object Type: Article
System: The UNT Digital Library
Majorana Electroformed Copper Mechanical Analysis (open access)

Majorana Electroformed Copper Mechanical Analysis

The MAJORANA DEMONSTRATOR is a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay. The DEMONSTRATOR will utilize ultra high purity electroformed copper for a variety of detector components and shielding. A preliminary mechanical evaluation was performed on the Majorana prototype electroformed copper material. Several samples were removed from a variety of positions on the mandrel. Tensile testing, optical metallography, scanning electron microscopy, and hardness testing were conducted to evaluate mechanical response. Analyses carried out on the Majorana prototype copper to this point show consistent mechanical response from a variety of test locations. Evaluation shows the copper meets or exceeds the design specifications.
Date: April 30, 2012
Creator: Overman, Nicole R.; Overman, Cory T.; Kafentzis, Tyler A.; Edwards, Danny J. & Hoppe, Eric W.
Object Type: Report
System: The UNT Digital Library
Investigating the effects of proton exchange membrane fuel cell conditions on carbon supported platinum electrocatalyst composition and performance (open access)

Investigating the effects of proton exchange membrane fuel cell conditions on carbon supported platinum electrocatalyst composition and performance

Changes that carbon-supported platinum electrocatalysts undergo in a proton exchange membrane fuel cell environment were simulated by ex situ heat treatment of catalyst powder samples at 150 C and 100% relative humidity. In order to study modifications that are introduced to chemistry, morphology, and performance of electrocatalysts, XPS, HREELS and three-electrode rotating disk electrode experiments were performed. Before heat treatment, graphitic content varied by 20% among samples with different types of carbon supports, with distinct differences between bulk and surface compositions within each sample. Following the aging protocol, the bulk and surface chemistry of the samples were similar, with graphite content increasing or remaining constant and Pt-carbide decreasing for all samples. From the correlation of changes in chemical composition and losses in performance of the electrocatalysts, we conclude that relative distribution of Pt particles on graphitic and amorphous carbon is as important for electrocatalytic activity as the absolute amount of graphitic carbon present
Date: April 30, 2012
Creator: Patel, A.; Artyushkova, K.; Atanassov, P.; Colbow, V.; Dutta, M.; Harvey, D. et al.
Object Type: Article
System: The UNT Digital Library
Advanced High-Temperature Reactor Dynamic System Model Development: April 2012 Status (open access)

Advanced High-Temperature Reactor Dynamic System Model Development: April 2012 Status

The Advanced High-Temperature Reactor (AHTR) is a large-output fluoride-salt-cooled high-temperature reactor (FHR). An early-phase preconceptual design of a 1500 MW(e) power plant was developed in 2011 [Refs. 1 and 2]. An updated version of this plant is shown as Fig. 1. FHRs feature low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. The AHTR is designed to be a “walk away” reactor that requires no action to prevent large off-site releases following even severe reactor accidents. This report describes the development of dynamic system models used to further the AHTR design toward that goal. These models predict system response during warmup, startup, normal operation, and limited off-normal operating conditions. Severe accidents that include a loss-of-fluid inventory are not currently modeled. The scope of the models is limited to the plant power system, including the reactor, the primary and intermediate heat transport systems, the power conversion system, and safety-related or auxiliary heat removal systems. The primary coolant system, the intermediate heat transport system and the reactor building structure surrounding them are shown in Fig. 2. These systems are modeled in the most detail because the passive interaction of the primary system with the …
Date: April 30, 2012
Creator: Qualls, A.L.; Cetiner, M.S. & Wilson, T.L., Jr.
Object Type: Report
System: The UNT Digital Library
Driving Down HB-LED Costs: Implementation of Process Simulation Tools and Temperature Control Methods of High Yield MOCVD Growth (open access)

Driving Down HB-LED Costs: Implementation of Process Simulation Tools and Temperature Control Methods of High Yield MOCVD Growth

The overall objective of this multi-faceted program is to develop epitaxial growth systems that meet a goal of 75% (4X) cost reduction in the epitaxy phase of HB-LED manufacture. A 75% reduction in yielded epitaxy cost is necessary in order to achieve the cost goals for widespread penetration of HB-LED’s into back-lighting units (BLU) for LCD panels and ultimately for solid-state lighting (SSL). To do this, the program will address significant improvements in overall equipment Cost of Ownership, or CoO. CoO is a model that includes all costs associated with the epitaxy portion of production. These aspects include cost of yield, capital cost, operational costs, and maintenance costs. We divide the program into three phases where later phases will incorporate the gains of prior phases. Phase one activities are enabling technologies. In collaboration with Sandia National Laboratories we develop a Fluent-compatible chemistry predictive model and a set of mid-infrared and near-ultraviolet pyrometer monitoring tools. Where previously the modeling of the reactor dynamics were studied within FLUENT alone, here, FLUENT and Chemkin are integrated into a comprehensive model of fluid dynamics and the most advanced transport equations developed for Chemkin. Specifically, the Chemkin model offered the key reaction terms for gas-phase …
Date: April 30, 2012
Creator: Quinn, William
Object Type: Report
System: The UNT Digital Library