An Innovative Ceramic Corrosion Protection System for Zircaloy Cladding (open access)

An Innovative Ceramic Corrosion Protection System for Zircaloy Cladding

Light Water reactor (LWR) fuel performance is currently limited by thermal, chemical and mechanical constraints associated with the design, fabrication, and operation of the fuel in incore operation. Corrosion of the zirconium based (Zircaloy-4) alloy cladding of the fuel is a primary limiting factor. Recent success at the University of Florida in developing thin ceramic films with great adhesive properties for metal substrates offers an innovative breakthrough for eliminating a major weakness of the Zircaloy clad. ?The University of Florida proposes to coat the existing Zircaloy clad tubes with a ceramic coating for corrosion protection. An added bonus of this approach would be the implementation of a boron-containing burnable poison outer layer will also be demonstrated as part of the ceramic coating development. In this proposed effort, emphasis will be on the ceramic coating with only demonstration of feasibility on the burnable outer coating approach. This proposed program i s expected to give a step change (approximately a doubling) in clad lifetime before failure due to corrosion. In the development of ceramic coatings for Zircaloy-4 clad, silicon carbide and zirconium carbide coatings will first be applied to Zircaloy-4 coupons and cladding samples by thermal assisted chemical vapor deposition, plasma assisted …
Date: February 19, 2003
Creator: Baney, Ronald H.; Tulenko, James S.; Butt, D.; Demkowicz, P.; Fuchs, G.; Schoessow, G. et al.
Object Type: Report
System: The UNT Digital Library
Rheology Modifiers for Radioactive Waste Slurries (open access)

Rheology Modifiers for Radioactive Waste Slurries

The goals of this study were to determine if trace levels of chemical additives could be used to reduce the rheological characteristics of radioactive waste slurries, identify potential chemical additives for this work and future testing, test a limited set of chemical additive candidates on simulated radioactive wastes, and develop advanced techniques to visualize the internal slurry structure and particle-particle interaction within the slurry.
Date: February 19, 2003
Creator: Calloway, T.B. Jr.
Object Type: Article
System: The UNT Digital Library
A High-Wavenumber Viscosity for High-Resolution Numerical Methods (open access)

A High-Wavenumber Viscosity for High-Resolution Numerical Methods

Numerical simulations of compressible flows are commonly based on the Euler equations when effects of viscosity are thought to be negligible. These equations admit singular solutions, even in cases where the initial and boundary conditions are smooth. So-called ''Euler solvers'' rely on numerical dissipation, explicitly or implicitly present in the scheme, to regularize the problem, such that physical solutions are selected.
Date: February 19, 2003
Creator: Cook, A & Cabot, W H
Object Type: Report
System: The UNT Digital Library
Technical Status Report for US Wind Farmers Network (open access)

Technical Status Report for US Wind Farmers Network

The theme of the work in this quarter was community-based wind and locally owned wind projects. The work Windustry has done is just beginning to touch the heart of the matter for a hugely interested audience of rural landowners and rural communities. We revised and published a Windustry Newsletter on two farmer owned wind projects called Minwind I and Minwind II. This article was largely researched and written last quarter but the principal individuals that organized the wind projects didn't want any more farmers calling them up than they already had, so they urged us to put a hold on the article or not publish it. This presented a unique problem for Windustry. Up to this point, we had not dealt with generating too much attention for a wind energy project. The story of a group of farmers and individuals pooling their resources for two locally owned commercial-scale wind projects is very compelling and the organizers of the projects were getting a great deal of attention from other farmers that want more details on the project. However, the organizers committed a large amount of their own resources toward the set up of this project which took many hours with their …
Date: February 19, 2003
Creator: Daniels, Lisa
Object Type: Report
System: The UNT Digital Library
Effect of surface carbon structure on the electrochemical performance of LiFePO{sub 4} (open access)

Effect of surface carbon structure on the electrochemical performance of LiFePO{sub 4}

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Date: February 19, 2003
Creator: Doeff, Marca M.; Hu, Yaoqin; McLarnon, Frank & Kostecki, Robert
Object Type: Article
System: The UNT Digital Library
Modeling of the Savannah River Site High Level Waste Evaporator Systems (open access)

Modeling of the Savannah River Site High Level Waste Evaporator Systems

Three evaporators are used to reduce the volume of waste in the waste tank farm at the Savannah River Site (SRS). Evaporators are crucial operation in the SRS waste processing and management system. Using the Aspen Custom Modeler(TM) (ACM) software package marketed by Aspen Technology, Inc., the evaporator dynamic flowsheet models have been constructed to simulate the behavior of the evaporator systems. The evaporator models are used to assist operations and planning. The models account for the basic arrangement and flowpath for the evaporators: (1) Feed system, (2) Concentrate system, (3) Overheads system, and (4) Steam system. This paper provides a detailed description of the model development and presents the result of a typical simulation scenario.
Date: February 19, 2003
Creator: Hang, T.
Object Type: Article
System: The UNT Digital Library
Development of an Initial Simulant for the Idaho Tank Farm Solids (open access)

Development of an Initial Simulant for the Idaho Tank Farm Solids

The goal of this task was to develop the methodology for producing a suitable simulant for waste solids and the fabrication of an initial simulant for use in the demonstrations and testing performed as part of the down-select process for disposition of INTEC tank waste. The analytical results from WM-182 and WM-183 tank samples were used as the basis for this work.
Date: February 19, 2003
Creator: Harbour, J.R.
Object Type: Report
System: The UNT Digital Library
Evaporative Deposition of Aluminum Coatings and Shapes with Grain Size Control (open access)

Evaporative Deposition of Aluminum Coatings and Shapes with Grain Size Control

The direct deposition of coatings with variable cross-section profiles presents a challenge for the use of physical vapor deposition technology. Coatings with constant and variable cross-section profiles are of interest for advancing the evaluation of material behavior under extreme loading conditions, as for example under high strain rate. The synthesis of a variable cross-section profile by design in the as-deposited condition requires process innovation. It is demonstrated that a thickness gradient in cross-section can be produced when the substrate is exposed to a highly collimated evaporation source. The exposure is governed using a variable position shutter as driven by a computer-controlled stepper motor. An example is shown for aluminum deposition in which the coating thickness varies linearly from one plateau to another forming a wedge shape. To deposit a controlled grain size in coatings as these wedge shapes, first requires an understanding of the affect of time at temperature. An examination of aluminum coatings with constant cross-section reveals that ideal-grain growth behavior is observed from the micron-to-millimeter scale for depositions at temperatures in excess of half the melt point.
Date: February 19, 2003
Creator: Jankowski, Alan Frederic & Hayes, Jeffrey P.
Object Type: Article
System: The UNT Digital Library
High Strain Rate-High Strain Response of an Ultrahigh Carbon Steel Containing 1.3% C and 3% SI (open access)

High Strain Rate-High Strain Response of an Ultrahigh Carbon Steel Containing 1.3% C and 3% SI

The mechanical response of a UHCS-1.3C material deformed at approximately 3000 s{sup -1} to large strains (60%) has been studied. The influence of three different heat treatments, which resulted in pearlitic, martensitic and tempered martensitic microstructures, on the stress-strain response has also been examined. Failure, at both the macroscopic and the microscopic levels, and the ability of the material to absorb energy in compression have been evaluated. Failure for all heat treatments occurred due to shear localization. However, in the pearlitic condition, extensive buckling of the carbide plates was observed and the UHCS-1.3C material exhibited significant potential for compressive ductility (>60%) and energy absorption due to the distributed buckling of these plates. In the pearlitic condition, localization occurred due to adiabatic shear bands, in which austenite formed. Subsequent cooling produced a divorced-eutectoid transformation with associated deformation, which resulted in a microstructure consisting of 50 to 100 nm sized grains. The results show the large potential for use of UHCS in applications involving dynamic loading.
Date: February 19, 2003
Creator: Lesuer, D R; Syn, C K; Sherby, O M & Kum, D W
Object Type: Article
System: The UNT Digital Library
Stodolsky's theorem and neutrino oscillation phases-for pedestrians. (open access)

Stodolsky's theorem and neutrino oscillation phases-for pedestrians.

Neutrino oscillations are experimentally observable only as a result of interference between neutrino states with different masses and the same energy. All interference effects between neutrino states having different energies are destroyed by the interaction between the incident neutrino and the neutrino detector. Erroneous results are frequently obtained by neglecting the neutrino-detector interactions.
Date: February 19, 2003
Creator: Lipkin, H. J.
Object Type: Report
System: The UNT Digital Library
Melt Rate Testing for the DWPF: Summary of FY02 Testing (open access)

Melt Rate Testing for the DWPF: Summary of FY02 Testing

A study performed in FY01 recommended that the Defense Waste Process Facility (DWPF) replace Frit 200 with Frit 320 for the processing of sludge batch 2 (SB2) to improve melt rate (Lambent et al., 2001) contingent upon additional testing which included slurry feeding. The FY02 melt rate program was developed to support this recommendation as well as to investigate alternative methods of improving melt rate above and beyond a change in frit composition. The integrated program was primarily based on a sound testing methodology from which the frit change was recommended. In addition, the program included the development of additional tools to provide further insight into melt rate enhancements. The overall strategy of the FY02 testing program was to design suites of melt rate tests based on recommendations from previous work that provided insight into other methods of improving melt rate for the DWPF. The objectives of the FY02 testing program included how melt rate might be influenced by increases in waste loading, differences in frit particle size, the use of batch chemicals rather than a pre-fabricated frit, and the impact of uranium. This report summarizes the equipment development and setup, procedures, and results of this testing, and includes recommendations …
Date: February 19, 2003
Creator: Lorier, T.H.
Object Type: Report
System: The UNT Digital Library
Methodology for Evaluation of Diagnostic Performance (open access)

Methodology for Evaluation of Diagnostic Performance

The proliferation of expensive technology in diagnostic medicine demands objective, meaningful assessments of diagnostic performance. Receiver Operating Characteristic (ROC) analysis is now recognized widely as the best approach to the task of measuring and specifying diagnostic accuracy (Metz, 1978; Swets and Pickett, 1982; Beck and Schultz, 1986; Metz, 1986; Hanley, 1989; Zweig and Campbell, 1993), which is defined as the extent to which diagnoses agree with actual states of health or disease (Fryback and Thornbury, 1991; National Council on Radiation Protection and Measurements, 1995). The primary advantage of ROC analysis over alternative methodologies is that it separates differences among diagnostic decisions that are due to actual differences in discrimination capacity from those that are due to decision-threshold effects (e.g., ''under-reading'' or ''over-reading''). An ROC curve measures diagnostic accuracy by displaying True Positive Fraction (TPF: the fraction of patients actually having the disease in question that is diagnosed correctly as ''positive'') as a function of False Positive Fraction (FPF: the fraction of patients actually without the disease that is diagnosed incorrectly as ''positive''). Different points on the ROC curve--i.e., different compromises between the specificity and the sensitivity of a diagnostic test, for a given inherent accuracy--can be achieved by adopting different …
Date: February 19, 2003
Creator: Metz, Charles E.
Object Type: Report
System: The UNT Digital Library
Low Voltage Spatial Light Modulator (open access)

Low Voltage Spatial Light Modulator

This project studied the feasibility of a Low-Voltage actuator technology that promises to reduce the switched voltage requirements and linearize the response of spatial light modulators. We created computer models that demonstrate substantial advantages offered by this technology, and fabricated and tested those devices. SLMs are electro-optic devices for modulating the phase, amplitude or angle of light beams, laser or other. Applications for arrays of SLMs include turbulence correction for high-speed optical communications, imaging through distorting media, input devices for holographic memories, optical manipulation of DNA molecules, and optical computers. Devices based on micro electro-mechanical systems (MEMS) technology have recently become of special interest because of their potential for greatly improved performance at a much lower cost than piezoelectric or liquid crystal based devices. The new MEMS-based SLM devices could have important applications in high-speed optical communication and remote optical sensing, in support of DoD and DOE missions. Virtually all previously demonstrated MEMS SLMs are based on parallel-plate capacitors where an applied voltage causes a mirror attached to a suspended electrode to move towards a fixed electrode. They require relatively high voltages, typically on the order of 100 V, resulting in (1) large transistor sizes, available only from specialized foundries …
Date: February 19, 2003
Creator: Papavasiliou, A
Object Type: Report
System: The UNT Digital Library
Evaluation of slurry injection technology for management of drilling wastes. (open access)

Evaluation of slurry injection technology for management of drilling wastes.

Each year, thousands of new oil and gas wells are drilled in the United States and around the world. The drilling process generates millions of barrels of drilling waste each year, primarily used drilling fluids (also known as muds) and drill cuttings. The drilling wastes from most onshore U.S. wells are disposed of by removing the liquids from the drilling or reserve pits and then burying the remaining solids in place (called pit burial). This practice has low cost and the approval of most regulatory agencies. However, there are some environmental settings in which pit burial is not allowed, such as areas with high water tables. In the U.S. offshore environment, many water-based and synthetic-based muds and cuttings can be discharged to the ocean if discharge permit requirements are met, but oil-based muds cannot be discharged at all. At some offshore facilities, drilling wastes must be either hauled back to shore for disposal or disposed of onsite through an injection process.
Date: February 19, 2003
Creator: Veil, J. A. & Dusseault, M. B.
Object Type: Report
System: The UNT Digital Library
Analysis of Induced Gas Releases During Retrieval of Hanford Double-Shell Tank Waste (open access)

Analysis of Induced Gas Releases During Retrieval of Hanford Double-Shell Tank Waste

Checklist for Technical Peer Review for PNNL-13782 Rev. 1 as requested to ensure that software used to support the DSA is compliant with software QA requirements. Radioactive waste is scheduled to be retrieved from Hanford double-shell tanks AN-103, AN-104, AN-105 and AW-101 and transferred to the vitrification plant beginning in about 2009. Retrieval may involve decanting the supernatant liquid and/or mixing the waste with jet pumps. In these four tanks, which contain relatively large volumes of retained gas, both operations are expected to induce buoyant displacement gas releases that can potentially raise the tank headspace hydrogen concentration to a level very near the lower flammability limit. This report describes the theory and detailed physical models for both the supernatant decant and jet mixing processes and presents the results from applying the models to these operations in the four tanks. The technical bases for input parameter distributions are elucidated.
Date: February 19, 2003
Creator: Wells, Beric E.
Object Type: Report
System: The UNT Digital Library
Pultonium Colloid-Facilitated Transport in the Environment - Experimental and Transport Modeling Evidence for Plutonium Migration Mechanisms (open access)

Pultonium Colloid-Facilitated Transport in the Environment - Experimental and Transport Modeling Evidence for Plutonium Migration Mechanisms

Natural inorganic colloids (< 1 micron particles) found in groundwater can sorb low-solubility actinides and may provide a pathway for transport in the subsurface. For example, Kerting et al found that Pu, associated with colloids fraction of the groundwater, was detected over 1 km away from the underground nuclear test at the Nevada Test Site (NTS) where it was originally deposited 28 years earlier. However, laboratory experiments have not identified the mechanisms by which Pu may sorb to colloids or exist as its own colloid and travel relatively unimpeded in the subsurface. Some data suggest that Pu sorption to colloids is a very fast process while desorption is very slow or simply does not occur. Slow desorption of Pu from colloids could allow Pu sorbed to a colloid to travel much farther than if sorption were an equilibrium process. However, PU sorption (and particularly desorption) data in the literature are scant and sometimes contradictory. In some cases, Pu desorption is rather fast, with rates dependent on colloid mineralogy. Moreover, the effect of sorption and desorption kinetics (as well as other mechanisms) on colloid-facilitated transport at the field scale has not been thoroughly evaluated. This is, in part, due to limitations …
Date: February 19, 2003
Creator: Zavarin, M.; Maxwell, R. M.; Kersting, A. B.; Zhao, P.; Sylwester, E. R.; Allen, P. G. et al.
Object Type: Article
System: The UNT Digital Library