Age-Related Degradation of Structures and Passive Components at Nuclear Power Plants. (open access)

Age-Related Degradation of Structures and Passive Components at Nuclear Power Plants.

None
Date: April 2, 2000
Creator: Braverman, J. I.
Object Type: Article
System: The UNT Digital Library
Effects of Parametric Variations on Seismic Analysis Methods for Non-Classically Damped Coupled Systems (open access)

Effects of Parametric Variations on Seismic Analysis Methods for Non-Classically Damped Coupled Systems

A comprehensive benchmark program was developed by Brookhaven National Laboratory (BNL) to perform an evaluation of state-of-the-art methods and computer programs for performing seismic analyses of coupled systems with non-classical damping. The program, which was sponsored by the US Nuclear Regulatory Commission (NRC), was designed to address various aspects of application and limitations of these state-of-the-art analysis methods to typical coupled nuclear power plant (NPP) structures with non-classical damping, and was carried out through analyses of a set of representative benchmark problems. One objective was to examine the applicability of various analysis methods to problems with different dynamic characteristics unique to coupled systems. The examination was performed using parametric variations for three simple benchmark models. This paper presents the comparisons and evaluation of the program participants' results to the BNL exact solutions for the applicable ranges of modeling dynamic characteristic parameters.
Date: April 2, 2000
Creator: Xu, J. & Degrassi, G.
Object Type: Article
System: The UNT Digital Library
Keys to successful D and D technology Deployments at the INEEL (open access)

Keys to successful D and D technology Deployments at the INEEL

Seven improved decontamination and decommissioning (D&D) technologies were successfully deployed at the Idaho National Engineering and Environmental Laboratory (INEEL) during the Accelerated Site Technology Deployment (ASTD) Integrated Decontamination and Decommissioning (ID&D) project. The use of these improved technologies saved the INEEL $462K in fiscal year 1999, and is projected to save about $14M over the next ten years. Since deploying new technologies on D&D projects shows great potential for cost-savings, factors that led to successful deployment have been documented. These factors are described here as they apply to the seven deployments at the INEEL to assist with deployments at other DOE sites.
Date: April 2, 2000
Creator: Smith, A. M.; Meservey, R. H. & Shoemaker, H.
Object Type: Article
System: The UNT Digital Library
A Machine Approach for Field Weakening of Permanent-Magnet Motors (open access)

A Machine Approach for Field Weakening of Permanent-Magnet Motors

The commonly known technology of field weakening for permanent-magnet (PM) motors is achieved by controlling the direct-axis current component through an inverter, without using mechanical variation of the air gap, a new machine approach for field weakening of PM machines by direct control of air-gap fluxes is introduced. The demagnetization situation due to field weakening is not an issue with this new method. In fact, the PMs are strengthened at field weakening. The field-weakening ratio can reach 1O:1 or higher. This technology is particularly useful for the PM generators and electric vehicle drives.
Date: April 2, 2000
Creator: Hsu, J.S.
Object Type: Article
System: The UNT Digital Library
Overview of the use of ATHENA for thermal-hydraulic analysis of systems with lead-bismuth coolant (open access)

Overview of the use of ATHENA for thermal-hydraulic analysis of systems with lead-bismuth coolant

The INEEL and MIT are investigating the suitability of lead-bismuth cooled fast reactor for producing low-cost electricity as well as for actinide burning. This paper is concerned with the general area of thermal-hydraulics of lead-bismuth cooled reactors. The ATHENA code is being used in the thermal-hydraulic design and analysis of lead-bismuth cooled reactors. The ATHENA code was reviewed to determine its applicability for simulating lead-bismuth cooled reactors. Two modifications were made to the code as a result of this review. Specifically, a correlation to represent heat transfer from rod bundles to a liquid metal and a void correlation based on data taken in a mixture of lead-bismuth and steam were added the code. The paper also summarizes the analytical work that is being performed with the code and plans for future analytical work.
Date: April 2, 2000
Creator: Davis, C. B. & Shieh, A. S.
Object Type: Article
System: The UNT Digital Library
Proton Boron Colliding Beams for Nuclear Fusion. (open access)

Proton Boron Colliding Beams for Nuclear Fusion.

None
Date: April 2, 2000
Creator: Ruggiero, A. G.
Object Type: Article
System: The UNT Digital Library
SCDAP/RELAP5 modeling of fluid heat transfer and flow losses through porous debris in a light water reactor (open access)

SCDAP/RELAP5 modeling of fluid heat transfer and flow losses through porous debris in a light water reactor

The SCDAP/RELAP5 code is being developed at the Idaho National Engineering and Environmental Laboratory under the primary sponsorship of the U.S. Nuclear Regulatory Commission (NRC) to provide best-estimate transient simulations of light water reactor coolant systems during severe accidents. This paper describes the modeling approach used in the SCDAP/RELAP5 code to calculate fluid heat transfer and flow losses through porous debris that has accumulated in the vessel lower head and core regions during the latter stages of a severe accident. The implementation of heat transfer and flow loss correlations into the code is discussed, and calculations performed to assess the validity of the modeling approach are described. The different modes of heat transfer in porous debris include: (1) forced convection to liquid, (2) forced convection to gas, (3) nucleate boiling, (4) transition boiling, (5) film boiling, and (6) transition from film boiling to convection to vapor. The correlations for flow losses in porous debris include frictional and form losses. The correlations for flow losses were integrated into the momentum equations in the RELAP5 part of the code. Since RELAP5 is a very general non-homogeneous non-equilibrium thermal-hydraulics code, the resulting modeling methodology is applicable to a wide range of debris thermal-hydraulic …
Date: April 2, 2000
Creator: Harvego, E. A. & Siefken, L. J.
Object Type: Article
System: The UNT Digital Library
SCDAP/RELAP5 modeling of movement of melted material through porous debris in lower head (open access)

SCDAP/RELAP5 modeling of movement of melted material through porous debris in lower head

A model is described for the movement of melted metallic material through a ceramic porous debris bed. The model is designed for the analysis of severe accidents in LWRs, wherein melted core plate material may slump onto the top of a porous bed of relocated core material supported by the lower head. The permeation of the melted core plate material into the porous debris bed influences the heatup of the debris bed and the heatup of the lower head supporting the debris. A model for mass transport of melted metallic material is applied that includes terms for viscosity and turbulence but neglects inertial and capillary terms because of their small value relative to gravity and viscous terms in the momentum equation. The relative permeability and passability of the porous debris are calculated as functions of debris porosity, particle size, and effective saturation. An iterative numerical solution is used to solve the set of nonlinear equations for mass transport. The effective thermal conductivity of the debris is calculated as a function of porosity, particle size, and saturation. The model integrates the equations for mass transport with a model for the two-dimensional conduction of heat through porous debris. The integrated model has …
Date: April 2, 2000
Creator: Siefken, L. J. & Harvego, E. A.
Object Type: Article
System: The UNT Digital Library
Structural Response of Degraded Reinforced Concrete Components. (open access)

Structural Response of Degraded Reinforced Concrete Components.

None
Date: April 2, 2000
Creator: Braverman, J. I.
Object Type: Article
System: The UNT Digital Library
Aquifer Transport of Th, U, Ra, and Rn In Solution and Colloids (open access)

Aquifer Transport of Th, U, Ra, and Rn In Solution and Colloids

The ability to safely store radioactive materials for long periods of time depends on our understanding of the conditions that mobilize the nuclei, which requires an understanding of the mechanisms of dissolution and transport in aquifers. The objective of this research was to gain an understanding of the dissolution and transport of naturally occurring uranium, thorium, and their radioactive daughter products in groundwater systems without using injected tracers or accidental contaminants. The study involved analyses of groundwater in and around the Brookhaven National Laboratory site and the water supply system. A theoretical model of continuous flow was developed considering chemical, physical, and geologic properties. This is the first model of water transport in the vadose zone and the groundwater table with water-rock interactions supplying insight into the problems of mobilization and precipitation. We derived clear theoretical predictions on U and Th behavior in groundwater. The combination of sound theory and good data was successful. Most of the variation in uranium isotopes was due to the original imprint of near-surface weathering and not to water-rock reactions at depth. It was shown that high radon content was not due to micropores in the minerals but a reflection of thorium precipitation on surfaces …
Date: April 2, 2001
Creator: Wasserburg, G. J.
Object Type: Report
System: The UNT Digital Library
(De)Constructing dimensions (open access)

(De)Constructing dimensions

We construct renormalizable, asymptotically free, four dimensional gauge theories that dynamically generate a fifth dimension.
Date: April 2, 2001
Creator: Arkani-Hamed, Nima; Cohen, Andrew G. & Georgi, Howard
Object Type: Article
System: The UNT Digital Library
Dynamic neurotransmitter interactions measured with PET (open access)

Dynamic neurotransmitter interactions measured with PET

Positron emission tomography (PET) has become a valuable interdisciplinary tool for understanding physiological, biochemical and pharmacological functions at a molecular level in living humans, whether in a healthy or diseased state. The utility of tracing chemical activity through the body transcends the fields of cardiology, oncology, neurology and psychiatry. In this, PET techniques span radiochemistry and radiopharmaceutical development to instrumentation, image analysis, anatomy and modeling. PET has made substantial contributions in each of these fields by providing a,venue for mapping dynamic functions of healthy and unhealthy human anatomy. As diverse as the disciplines it bridges, PET has provided insight into an equally significant variety of psychiatric disorders. Using the unique quantitative ability of PET, researchers are now better able to non-invasively characterize normally occurring neurotransmitter interactions in the brain. With the knowledge that these interactions provide the fundamental basis for brain response, many investigators have recently focused their efforts on an examination of the communication between these chemicals in both healthy volunteers and individuals suffering from diseases classically defined as neurotransmitter specific in nature. In addition, PET can measure the biochemical dynamics of acute and sustained drug abuse. Thus, PET studies of neurotransmitter interactions enable investigators to describe a multitude …
Date: April 2, 2001
Creator: Schiffer, W. K. & Dewey, S. L.
Object Type: Book
System: The UNT Digital Library
Experimental Results in Support of Simulating Progressive Crush in Carbon-Fiber Textile Composites (open access)

Experimental Results in Support of Simulating Progressive Crush in Carbon-Fiber Textile Composites

This report summarizes the findings of an experimental program conducted to support the modeling of the crush behavior of triaxial braid carbon fiber composites. The matrix material as well as braided panels and tubes were characterized in order to determine material properties, to assess failure modes, and to provide a test bed for new analytical and numerical tools developed specifically for braided composites. The matrix material selected by the ACC was an epoxy vinyl ester (Ashland Hetron 922). Tensile tests were used to compare two formulations-one used by the ACC and one recommended by the resin supplier. The latter was a faster reacting system and gelled in one-third the time of the ACC formulation. Both formulations had an average elongation at failure that was only half of the resin supplier's reported value. Only one specimen of each type came close to the reported elongation value and it was shown that failure invariably initiated at both surface and internal defects. Overall, the tensile properties of the two formulations were nearly identical, but those of the ACC system were more consistent. The properties of the ACC matrix formulation were measured in tension, shear, and compression and the average properties obtained in these …
Date: April 2, 2001
Creator: DeTeresa, S J; Allison, L M; Cunningham, B J; Freeman, DC; Saculla, M D; Sanchez, R J et al.
Object Type: Report
System: The UNT Digital Library
Mechanisms of dislocation reduction in GaN using an intermediate temperature interlayer (open access)

Mechanisms of dislocation reduction in GaN using an intermediate temperature interlayer

None
Date: April 2, 2001
Creator: Bourret-Courchesne, E.D.; Yu, K.M.; Benamara, M.; Liliental-Weber, Z. & Washburn, J.
Object Type: Article
System: The UNT Digital Library
Production and application of synthetic precursors labeled with carbon-11 and fluorine-18 (open access)

Production and application of synthetic precursors labeled with carbon-11 and fluorine-18

It is evident from this chapter that there is enormous flexibility both in the selection of the nature of the radioisotope and ways to generate it, as well as in the selection of the labeling precursor to appropriately attach that radioisotope to some larger biomolecule of interest. The arsenal of radiolabeling precursors now available to the chemist is quite extensive, and without a doubt will continue to grow as chemists develop new ones. However, the upcoming years will perhaps reflect a greater effort in refining existing methods for preparing some of those precursors that are already available to us. For example, the use of solid-phase reactions to accomplish in a single step what would normally take several using conventional solvent-based reactions has already been shown to work in many occasions. The obvious advantage here is that processes become more amenable to system automation thus affording greater reliability in day-to-day operations. There are perhaps other technologies in science that have yet to be realized by the chemist in the PET laboratory that could provide a similar or even a greater benefit. One only needs to be open to new ideas, and imaginative enough to apply them to the problems at hand.
Date: April 2, 2001
Creator: Ferrieri, R. A.
Object Type: Book
System: The UNT Digital Library
Quantitative Estimation of Trace Chemicals in Industrial Effluents with the Sticklet Transform Method (open access)

Quantitative Estimation of Trace Chemicals in Industrial Effluents with the Sticklet Transform Method

Application of a novel transform operator, the Sticklet transform, to the quantitative estimation of trace chemicals in industrial effluent plumes is reported. The sticklet transform is a superset of the well-known derivative operator and the Haar wavelet, and is characterized by independently adjustable lobe width and separation. Computer simulations demonstrate that they can make accurate and robust concentration estimates of multiple chemical species in industrial effluent plumes in the presence of strong clutter background, interferent chemicals and random noise. In this paper they address the application of the sticklet transform in estimating chemical concentrations in effluent plumes in the presence of atmospheric transmission effects. They show that this transform retains the ability to yield accurate estimates using on-plume/off-plume measurements that represent atmospheric differentials up to 10% of the full atmospheric attenuation.
Date: April 2, 2001
Creator: Mehta, N C; Scharlemann, E T & Stevens, C G
Object Type: Article
System: The UNT Digital Library
Representative sampling using single-pulse laser ablation withinductively coupled plasma mass spectroscopy (open access)

Representative sampling using single-pulse laser ablation withinductively coupled plasma mass spectroscopy

Single pulse laser ablation sampling with inductively coupled plasma mass spectrometry (ICP-MS) was assessed for accurate chemical analysis. Elemental fractionation (e.g. Pb/U), the quantity of ablated mass (crater volume), ICP-MS intensity and the particle contribution (spike signal) during single pulse ablation of NIST 610 glass were investigated. Pb/U fractionation significantly changed between the first and second laser pulse and showed strong irradiance dependence. The Pb/U ratio obtained by the first pulse was usually higher than that of the second pulse, with the average value close to the representative level. Segregation during laser ablation is proposed to explain the composition change between the first and second pulse. Crater volume measurements showed that the second pulse produced significantly more ablated mass. A roll-off of the crater depth occurred at {approx}750 GW/cm{sup 2}. The absolute ICP-MS intensity from the second pulse showed no correlation with crater depth. Particle induced spikes on the transit signal showed irradiance and elemental species dependence.
Date: April 2, 2001
Creator: Liu, Haichen; Mao, Xianglei & Russo, Richard E.
Object Type: Article
System: The UNT Digital Library
Solid Solubilities of Pu, U, Gd and Hf in Candidate Ceramic Nuclear Wasteforms (open access)

Solid Solubilities of Pu, U, Gd and Hf in Candidate Ceramic Nuclear Wasteforms

This goal of this research project was to determine the solid solubility of Pu, U, Gd, and Hf in candidate ceramics for immobilization of high-level nuclear waste. The experimental approach was to saturate each phase by adding more than the solid solubility limit of the given cation, using a nominated substitution scheme, and then analyzing the candidate phase that formed to evaluate the solid solubility limit under firing conditions. Confirmation that the solid solution limit had been reached insofar as other phases rich in the cation of interest was also required. The candidate phases were monazite, titanite, zirconolite, perovskite, apatite, pyrochlore, and brannerite. The valences of Pu and U were typically deduced from the firing atmosphere, and charge balancing in the candidate phase composition as evaluated from electron microscopy, although in some cases it was measured directly by x-ray absorption and diffuse reflectance spectroscopies (for U). Tetravalent Pu and U have restricted (< 0.1 formula units) solid solubility in apatite, titanite, and perovskite. Trivalent Pu has a larger solubility in apatite and perovskite than Pu4+. U3+ appears to be a credible species in reduced perovskite with a solubility of {approximately} 0.25 f.u. as opposed to {approximately} 0.05 f.u. for U4+. …
Date: April 2, 2001
Creator: Vance, Eric R.; Carter, M. L.; Lumpkin, G. R.; Day, R. A. & Begg, B. D.
Object Type: Report
System: The UNT Digital Library
STRATEGIES FOR QUANTIFYING PET IMAGING DATA FROM TRACER STUDIES OF BRAIN RECEPTORS AND ENZYMES. (open access)

STRATEGIES FOR QUANTIFYING PET IMAGING DATA FROM TRACER STUDIES OF BRAIN RECEPTORS AND ENZYMES.

A description of some of the methods used in neuroreceptor imaging to distinguish changes in receptor availability has been presented in this chapter. It is necessary to look beyond regional uptake of the tracer since uptake generally is affected by factors other than the number of receptors for which the tracer has affinity. An exception is the infusion method producing an equilibrium state. The techniques vary in complexity some requiring arterial blood measurements of unmetabolized tracer and multiple time uptake data. Others require only a few plasma and uptake measurements and those based on a reference region require no plasma measurements. We have outlined some of the limitations of the different methods. Laruelle (1999) has pointed out that test/retest studies to which various methods can be applied are crucial in determining the optimal method for a particular study. The choice of method will also depend upon the application. In a clinical setting, methods not involving arterial blood sampling are generally preferred. In the future techniques for externally measuring arterial plasma radioactivity with only a few blood samples for metabolite correction will extend the modeling options of clinical PET. Also since parametric images can provide information beyond that of ROI analysis, …
Date: April 2, 2001
Creator: Logan, J.
Object Type: Book
System: The UNT Digital Library
Time-Accurate Computation of Viscous Flow Around Deforming Bodies Using Overset Grids (open access)

Time-Accurate Computation of Viscous Flow Around Deforming Bodies Using Overset Grids

Dynamically evolving boundaries and deforming bodies interacting with a flow are commonly encountered in fluid dynamics. However, the numerical simulation of flows with dynamic boundaries is difficult with current methods. We propose a new method for studying such problems. The key idea is to use the overset grid method with a thin, body-fitted grid near the deforming boundary, while using fixed Cartesian grids to cover most of the computational domain. Our approach combines the strengths of earlier moving overset grid methods for rigid body motion, and unstructured grid methods for Aow-structure interactions. Large scale deformation of the flow boundaries can be handled without a global regridding, and in a computationally efficient way. In terms of computational cost, even a full overset grid regridding is significantly cheaper than a full regridding of an unstructured grid for the same domain, especially in three dimensions. Numerical studies are used to verify accuracy and convergence of our flow solver. As a computational example, we consider two-dimensional incompressible flow past a flexible filament with prescribed dynamics.
Date: April 2, 2001
Creator: Fast, P & Henshaw, W D
Object Type: Article
System: The UNT Digital Library
Water Velocity Measurement on an Extended-Length Submerged Bar Screen at John Day Dam (open access)

Water Velocity Measurement on an Extended-Length Submerged Bar Screen at John Day Dam

This report describes a study of water velocity around an extended-length submerged bar screen (ESBS) at John Day Dam. The study was conducted for the U.S. Army Corps of Engineers by AScI Corporation and MEVATEC Corporation in March of 2000. This report was prepared by Pacific Northwest National Laboratory. ESBS are being studied as one method for diverting juvenile migrating fish from the dam's turbine intakes into the gate well and through the juvenile fish bypass channels.
Date: April 2, 2001
Creator: Weiland, Mark A. & Escher, Charles
Object Type: Report
System: The UNT Digital Library
Water Velocity Measurement on an Extended-Length Submerged Bar Screen at John Day Dam (open access)

Water Velocity Measurement on an Extended-Length Submerged Bar Screen at John Day Dam

This report describes a study of water velocity around an extended-length submerged bar screen (ESBS) at John Day Dam. The study was conducted for the U.S. Army Corps of Engineers by AScI Corporation and MEVATEC Corporation in March of 2000. This report was prepared by Pacific Northwest National Laboratory. ESBS are being studied as one method for diverting juvenile migrating fish from the dam's turbine intakes into the gate well and through the juvenile fish bypass channels.
Date: April 2, 2001
Creator: Weiland, Mark A
Object Type: Report
System: The UNT Digital Library
Construction Site Storm Water Sampling California's New Construction Sampling and Analysis Requirements (open access)

Construction Site Storm Water Sampling California's New Construction Sampling and Analysis Requirements

The California State Water Resources Control Board (State Board) originally issued a National Pollutant Discharge System (NPDES) permit for storm water discharges associated with construction activities in 1992. This NPDES permit was issued as a general permit, applicable throughout the state (with certain exceptions). The general construction permit was made site-specific by a discharger-developed Storm Water Pollution Prevention Plan (SWPPP). As with most NPDES construction storm water permits, monitoring requirements were limited to inspections. Sampling and analysis of discharges was not specifically required, but a Regional Water Quality Control Board (Regional Board) could require additional monitoring. In 1999, the State -Board revised and reissued its construction general permit. While the 1999 permit significantly enhanced the erosion and sediment control descriptions and requirements, and expanded the inspection program, sampling and analysis was still not required. Environmental advocacy groups took exception to the absence of sampling requirements and sought relief in court to add sampling and analysis. In 2001, the State Board in response to the court order adopted a resolution requiring sampling and analysis of construction site runoff under two conditions. Turbidity and/or sediment sampling is required when construction site runoff enters water bodies determined to impaired for sediment or turbidity. …
Date: April 2, 2002
Creator: Forrest, C.L. & Mathews, S.
Object Type: Article
System: The UNT Digital Library
Damage Mechanisms of Filled Siloxanes for Predictive Multiscale Modeling of Aging Behavior (open access)

Damage Mechanisms of Filled Siloxanes for Predictive Multiscale Modeling of Aging Behavior

Predictions of component performance versus lifetime are often risky for complex materials in which there may be many underlying aging or degradation mechanisms. In order to develop more accurate predictive models for silica-filled siloxane components, we are studying damage mechanisms over a broad range of size domains, linked together through several modeling efforts. Atomistic and molecular dynamic modeling has elucidated the chemistry of the silica filler to polymer interaction, as this interaction plays a key role in this material's aging behavior. This modeling work has been supported by experimental data on the removal of water from the silica surface, the effect of the surrounding polymer on this desiccation, and on the subsequent change in the mechanical properties of the system. Solid State NMR efforts have characterized the evolution of the polymer and filler dynamics as the material is damaged through irradiation or desiccation. These damage signatures have been confirmed by direct measurements of changes in polymer crosslink density and filler interaction as measured by solvent swelling, and by mechanical property tests. Data from the changes at these molecular levels are simultaneously feeding the development of age-aware constitutive models for polymer behavior. In addition, the microstructure of the foam, including under …
Date: April 2, 2002
Creator: Balazs, B; Maxwell, R; de Teresa, S; Dinh, L & Gee, R
Object Type: Article
System: The UNT Digital Library