PR-EDB: Power Reactor Embrittlement Database - Version 3 (open access)

PR-EDB: Power Reactor Embrittlement Database - Version 3

The aging and degradation of light-water reactor pressure vessels is of particular concern because of their relevance to plant integrity and the magnitude of the expected irradiation embrittlement. The radiation embrittlement of reactor pressure vessel materials depends on many factors, such as neutron fluence, flux, and energy spectrum, irradiation temperature, and preirradiation material history and chemical compositions. These factors must be considered to reliably predict pressure vessel embrittlement and to ensure the safe operation of the reactor. Large amounts of data from surveillance capsules are needed to develop a generally applicable damage prediction model that can be used for industry standards and regulatory guides. Furthermore, the investigations of regulatory issues such as vessel integrity over plant life, vessel failure, and sufficiency of current codes, Standard Review Plans (SRPs), and Guides for license renewal can be greatly expedited by the use of a well-designed computerized database. The Power Reactor Embrittlement Database (PR-EDB) is such a comprehensive collection of data for U.S. designed commercial nuclear reactors. The current version of the PR-EDB lists the test results of 104 heat-affected-zone (HAZ) materials, 115 weld materials, and 141 base materials, including 103 plates, 35 forgings, and 3 correlation monitor materials that were irradiated in …
Date: March 1, 2008
Creator: Wang, Jy-An John & Subramani, Ranjit
Object Type: Report
System: The UNT Digital Library
Photo-Activated Low Temperature, Micro Fuel Cell Power Source (open access)

Photo-Activated Low Temperature, Micro Fuel Cell Power Source

A Key objective of this program is to identify electrodes that will make it possible to significantly reduce the operating temperature of micro-SOFC and thin film-based SOFCs. Towards this end, efforts are directed towards: (a) identifying the key rate limiting steps which limit presently utilized electrodes from performing at reduced temperatures, as well as, (b) investigating the use of optical, as opposed to thermal energy, as a means for photocatalyzing electrode reactions and enabling reduced operating temperatures. During Phase I, the following objectives were achieved: (a) assembly and testing of our unique Microprobe Thin Film Characterization System; (b) fabrication of the model cathode materials system in thin film form by both PLD and ink jet printing; and (c) the successful configuration and testing of the model materials as cathodes in electrochemical cells. A further key objective (d) to test the potential of illumination in enhancing electrode performance was also achieved.
Date: March 30, 2007
Creator: Tuller, Harry L.
Object Type: Report
System: The UNT Digital Library
Public Health-Related Impacts of Climate Change in California (open access)

Public Health-Related Impacts of Climate Change in California

In June 2005 Governor Arnold Schwarzenegger issued Executive Order S-3-05 that set greenhouse gas emission reduction targets for California, and directed the Secretary of the California Environmental Protection Agency to report to the governor and the State legislature by January 2006 and biannually thereafter on the impacts to California of global warming, including impacts to water supply, public health, agriculture, the coastline, and forestry, and to prepare and report on mitigation and adaptation plans to combat these impacts. This report is a part of the report to the governor and legislature, and focuses on public health impacts that have been associated with climate change. Considerable evidence suggests that average ambient temperature is increasing worldwide, that temperatures will continue to increase into the future, and that global warming will result in changes to many aspects of climate, including temperature, humidity, and precipitation (McMichael and Githeko, 2001). It is expected that California will experience changes in both temperature and precipitation under current trends. Many of the changes in climate projected for California could have ramifications for public health (McMichael and Githeko, 2001), and this document summarizes the impacts judged most likely to occur in California, based on a review of available peer-reviewed …
Date: March 2006
Creator: Drechsler, Deborah M.; Motallebi, Nehzat; Kleeman, Michael; Cayan, Dan; Hayhoe, Katherine; Kalkstein, Laurence S. et al.
Object Type: Report
System: The UNT Digital Library
HYDROGEN EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF FORGED STAINLESS STEELS (open access)

HYDROGEN EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF FORGED STAINLESS STEELS

The effect of hydrogen on the fracture toughness properties of Types 304L, 316L and 21-6-9 forged stainless steels was investigated. Fracture toughness samples were fabricated from forward-extruded forgings. Samples were uniformly saturated with hydrogen after exposure to hydrogen gas at 34 MPa or 69 and 623 K prior to testing. The fracture toughness properties were characterized by measuring the J-R behavior at ambient temperature in air. The results show that the hydrogen-charged steels have fracture toughness values that were about 50-60% of the values measured for the unexposed steels. The reduction in fracture toughness was accompanied by a change in fracture appearance. Both uncharged and hydrogen-charged samples failed by microvoid nucleation and coalescence, but the fracture surfaces of the hydrogen-charged steels had smaller microvoids. Type 316L stainless steel had the highest fracture toughness properties and the greatest resistance to hydrogen degradation.
Date: March 28, 2008
Creator: Morgan, M
Object Type: Article
System: The UNT Digital Library
Downregulation of Protein 4.1R impairs centrosome function,bipolar spindle organization and anaphase (open access)

Downregulation of Protein 4.1R impairs centrosome function,bipolar spindle organization and anaphase

Centrosomes nucleate and organize interphase MTs and areinstrumental in the assembly of the mitotic bipolar spindle. Here wereport that two members of the multifunctional protein 4.1 family havedistinct distributions at centrosomes. Protein 4.1R localizes to maturecentrioles whereas 4.1G is a component of the pericentriolar matrixsurrounding centrioles. To selectively probe 4.1R function, we used RNAinterference-mediated depletion of 4.1R without decreasing 4.1Gexpression. 4.1R downregulation reduces MT anchoring and organization atinterphase and impairs centrosome separation during prometaphase.Metaphase chromosomes fail to properly condense/align and spindleorganization is aberrant. Notably 4.1R depletion causes mislocalizationof its binding partner NuMA (Nuclear Mitotic Apparatus Protein),essential for spindle pole focusing, and disrupts ninein. Duringanaphase/telophase, 4.1R-depleted cells have lagging chromosomes andaberrant MT bridges. Our data provide functional evidence that 4.1R makescrucial contributions to centrosome integrity and to mitotic spindlestructure enabling mitosis and anaphase to proceed with the coordinatedprecision required to avoid pathological events.
Date: March 17, 2006
Creator: Spence, Jeffrey R.; Go, Minjoung M.; Bahmanyar, S.; Barth,A.I.M. & Krauss, Sharon Wald
Object Type: Article
System: The UNT Digital Library
A CCD Camera with Electron Decelerator for Intermediate Voltage Electron Microscopy (open access)

A CCD Camera with Electron Decelerator for Intermediate Voltage Electron Microscopy

Electron microscopists are increasingly turning to Intermediate Voltage Electron Microscopes (IVEMs) operating at 300 - 400 kV for a wide range of studies. They are also increasingly taking advantage of slow-scan charge coupled device (CCD) cameras, which have become widely used on electron microscopes. Under some conditions CCDs provide an improvement in data quality over photographic film, as well as the many advantages of direct digital readout. However, CCD performance is seriously degraded on IVEMs compared to the more conventional 100 kV microscopes. In order to increase the efficiency and quality of data recording on IVEMs, we have developed a CCD camera system in which the electrons are decelerated to below 100 kV before impacting the camera, resulting in greatly improved performance in both signal quality and resolution compared to other CCDs used in electron microscopy. These improvements will allow high-quality image and diffraction data to be collected directly with the CCD, enabling improvements in data collection for applications including high-resolution electron crystallography, single-particle reconstruction of protein structures, tomographic studies of cell ultrastructure and remote microscope operation. This approach will enable us to use even larger format CCD chips that are being developed with smaller pixels.
Date: March 17, 2008
Creator: Downing, Kenneth H; Downing, Kenneth H. & Mooney, Paul E.
Object Type: Article
System: The UNT Digital Library
Center-stabilized Yang-Mills Theory:Confinement and Large N Volume Independence (open access)

Center-stabilized Yang-Mills Theory:Confinement and Large N Volume Independence

We examine a double trace deformation of SU(N) Yang-Mills theory which, for large N and large volume, is equivalent to unmodified Yang-Mills theory up to O(1/N{sup 2}) corrections. In contrast to the unmodified theory, large N volume independence is valid in the deformed theory down to arbitrarily small volumes. The double trace deformation prevents the spontaneous breaking of center symmetry which would otherwise disrupt large N volume independence in small volumes. For small values of N, if the theory is formulated on R{sup 3} x S{sup 1} with a sufficiently small compactification size L, then an analytic treatment of the non-perturbative dynamics of the deformed theory is possible. In this regime, we show that the deformed Yang-Mills theory has a mass gap and exhibits linear confinement. Increasing the circumference L or number of colors N decreases the separation of scales on which the analytic treatment relies. However, there are no order parameters which distinguish the small and large radius regimes. Consequently, for small N the deformed theory provides a novel example of a locally four-dimensional pure gauge theory in which one has analytic control over confinement, while for large N it provides a simple fully reduced model for Yang-Mills theory. …
Date: March 21, 2008
Creator: Unsal, Mithat; /SLAC /Stanford U., Phys. Dept.; Yaffe, Laurence G. & /Washington U., Seattle
Object Type: Article
System: The UNT Digital Library
Low Mach Number Modeling of Type Ia Supernovae. II. EnergyEvolution (open access)

Low Mach Number Modeling of Type Ia Supernovae. II. EnergyEvolution

The convective period leading up to a Type Ia supernova (SNIa) explosion is characterized by very low Mach number flows, requiringhydrodynamical methods well-suited to long-time integration. We continuethe development of the low Mach number equation set for stellar scaleflows by incorporating the effects of heat release due to externalsources. Low Mach number hydrodynamics equations with a time-dependentbackground state are derived, and a numerical method based on theapproximate projection formalism is presented. We demonstrate throughvalidation with a fully compressible hydrodynamics code that this lowMach number model accurately captures the expansion of the stellaratmosphere as well as the local dynamics due to external heat sources.This algorithm provides the basis for an efficient simulation tool forstudying the ignition of SNe Ia.
Date: March 28, 2006
Creator: Almgren, Ann S.; Bell, John B.; Rendleman, Charles A. & Zingale,Mike
Object Type: Article
System: The UNT Digital Library
Microbunching and Beam Break Up in DUV FEL Accelerator (open access)

Microbunching and Beam Break Up in DUV FEL Accelerator

We present the results of electron beam longitudinal modulation studies in the DUV-FEL accelerator. For bunch length determination we used the 'zero-phasing' method, based on a measurement of the chirped electron bunch energy spectra. The measurements revealed a spiky structure in the longitudinal phase space [1]. A model based on space charge effect is considered [2] to explain of the obtained phenomena. The analysis of the energy spectra has shown a sensitivity of the structure to the electron beam peak current, energy and longitudinal non-uniformity of the RF gun drive laser. Analytical calculations have demonstrated a qualitative agreement with experimental observations. Several experiments have been made to compare with theory; measured results are reviewed in this paper. The obtained effect is briefly discussed in relation to high brightness accelerators.
Date: March 17, 2008
Creator: Shaftan, T.; Carr, L.; Loos, H.; Sheehy, B.; Graves, William S.; Huang, Z. et al.
Object Type: Article
System: The UNT Digital Library
Fox-2 Splicing Factor Binds to a Conserved Intron Motif to PromoteInclusion of Protein 4.1R Alternative Exon 16 (open access)

Fox-2 Splicing Factor Binds to a Conserved Intron Motif to PromoteInclusion of Protein 4.1R Alternative Exon 16

Activation of protein 4.1R exon 16 (E16) inclusion during erythropoiesis represents a physiologically important splicing switch that increases 4.1R affinity for spectrin and actin. Previous studies showed that negative regulation of E16 splicing is mediated by the binding of hnRNP A/B proteins to silencer elements in the exon and that downregulation of hnRNP A/B proteins in erythroblasts leads to activation of E16 inclusion. This paper demonstrates that positive regulation of E16 splicing can be mediated by Fox-2 or Fox-1, two closely related splicing factors that possess identical RNA recognition motifs. SELEX experiments with human Fox-1 revealed highly selective binding to the hexamer UGCAUG. Both Fox-1 and Fox-2 were able to bind the conserved UGCAUG elements in the proximal intron downstream of E16, and both could activate E16 splicing in HeLa cell co-transfection assays in a UGCAUG-dependent manner. Conversely, knockdown of Fox-2 expression, achieved with two different siRNA sequences resulted in decreased E16 splicing. Moreover, immunoblot experiments demonstrate mouse erythroblasts express Fox-2, but not Fox-1. These findings suggest that Fox-2 is a physiological activator of E16 splicing in differentiating erythroid cells in vivo. Recent experiments show that UGCAUG is present in the proximal intron sequence of many tissue-specific alternative exons, and …
Date: March 1, 2006
Creator: Ponthier, Julie L.; Schluepen, Christina; Chen, Weiguo; Lersch,Robert A.; Gee, Sherry L.; Hou, Victor C. et al.
Object Type: Article
System: The UNT Digital Library
High-Strength / High Alkaline Resistant Fe-Phosphate Glass Fibers as Concrete Reinforcement (open access)

High-Strength / High Alkaline Resistant Fe-Phosphate Glass Fibers as Concrete Reinforcement

Calcium-iron-phosphate glasses were developed whose chemical durabilities in alkaline solutions (pH 13) were comparable or superior to those of commercial alkaline-resistant (AR) silica-based glasses. However, the tensile strength of Ca-Fe-phosphate fibers, after being exposed to alkaline environments, including wet Portland cement pastes, is lower than that of current AR silicate fibers. Another series of Ca-Fe-phosphate glasses were developed with excellent chemical durability in strong acidic solutions (H2SO4, HF), indicating potential applications where silica-based fibers degrade very quickly, including E-glass. The new Ca-Fe-phosphate glasses can be melted and processed 300 to 500°C lower than silica-based glasses. This offers the possibility of manufacturing glass fibers with lower energy costs by 40-60% and the potential to reduce manufacturing waste and lower gas emissions. It was found that Ca-Fe-phosphate melts can be continuously pulled into fibers depending on the slope of the viscosity-temperature curve and with viscosity ~100 poise, using multi-hole Pt/Rh bushings.
Date: March 31, 2008
Creator: Velez, Mariano
Object Type: Report
System: The UNT Digital Library
POTENTIAL FOR HYDROGEN BUILDUP IN HANFORD SEALED AIR FILLED NUCLEAR STORAGE VESSELS (open access)

POTENTIAL FOR HYDROGEN BUILDUP IN HANFORD SEALED AIR FILLED NUCLEAR STORAGE VESSELS

None
Date: March 11, 2008
Creator: BE, HEY
Object Type: Report
System: The UNT Digital Library
NAWIG News: The Quarterly Newsletter of the Native American Wind Interest Group, Spring 2008 (open access)

NAWIG News: The Quarterly Newsletter of the Native American Wind Interest Group, Spring 2008

The United States is home to more than 700 American Indian tribes and Native Alaska villages and corporations located on 96 million acres. Many of these tribes and villages have excellent wind resources that could be commercially developed to meet their electricity needs or for electricity export. The Wind Powering America program engages Native Americans in wind energy development, and as part of that effort, the NAWIG newsletter informs readers of events in the Native American/wind energy community. This issue features an interview with Steven J. Morello, director of DOE's newly formed Office of Indian Energy Policy and Programs, and a feature on the newly installed Vestas V-47 turbine at Turtle Mountain Community College.
Date: March 1, 2008
Creator: Baranowski, R.
Object Type: Report
System: The UNT Digital Library
Parameter identification for the electrical modeling of semiconductor bridges. (open access)

Parameter identification for the electrical modeling of semiconductor bridges.

Semiconductor bridges (SCBs) are commonly used as initiators for explosive and pyrotechnic devices. Their advantages include reduced voltage and energy requirements and exceptional safety features. Moreover, the design of systems which implement SCBs can be expedited using electrical simulation software. Successful use of this software requires that certain parameters be correctly chosen. In this paper, we explain how these parameters can be identified using optimization. We describe the problem focusing on the application of a direct optimization method for its solution, and present some numerical results.
Date: March 1, 2005
Creator: Gray, Genetha Anne
Object Type: Report
System: The UNT Digital Library
Materials Evaluation Test Series (METS) 04, 05, and 06 (open access)

Materials Evaluation Test Series (METS) 04, 05, and 06

The purpose of this work is to examine the environmental, safety, health and operational aspects of detonating a confined explosive test apparatus that has been designed to maximize the dynamics of impact on beryllium metal components for Contained Firing Facility (CFF) applications. A combination of experimental collection and evaluation methods were designed and implemented to provide an evaluation of immediately postdetonation by-products reflecting a potential worst-case scenario beryllium aerosolization explosive event. The collective Material Evaluation Test Series (METS) 04 - 06 provided explosive devices designed to scale for the dedicated METS firing tank that would provide a post-detonation internal environment comparable to the CFF. The experimental results provided appropriate information to develop operational parameters to be considered for conducting full-scale beryllium-containing experimental tests with similar designs within CFF and B801A. These operational procedures include the inclusion of chelating agents in pre-shot CFF cardboard containers with a minimum of 600 gallons content, an extended time period post-test before purging the CFF chamber, and an adaptation of approaches toward applications of the scrubber and HEPA systems during the post-shot sequence for an integrated environmental, safety, and health approach. In addition, re-entry and film retrieval procedures will be adapted, in line with abatement …
Date: March 23, 2006
Creator: Zalk, D.; Ingram, C.; Simmons, L.; Arganbright, R.; Lyle, J. & Wong, K.
Object Type: Report
System: The UNT Digital Library
Rainwater Wildlife Area, Watershed Management Plan, A Columbia Basin Wildlife Mitigation Project, 2002. (open access)

Rainwater Wildlife Area, Watershed Management Plan, A Columbia Basin Wildlife Mitigation Project, 2002.

This Management Plan has been developed by the Confederated Tribes of the Umatilla Indian Reservation (CTUIR) to document how the Rainwater Wildlife Area (formerly known as the Rainwater Ranch) will be managed. The plan has been developed under a standardized planning process developed by the Bonneville Power Administration (BPA) for Columbia River Basin Wildlife Mitigation Projects (See Appendix A and Guiding Policies Section below). The plan outlines the framework for managing the project area, provides an assessment of existing conditions and key resource issues, and presents an array of habitat management and enhancement strategies. The plan culminates into a 5-Year Action Plan that will focus our management actions and prioritize funding during the Fiscal 2001-2005 planning period. This plan is a product of nearly two years of field studies and research, public scoping, and coordination with the Rainwater Advisory Committee. The committee consists of representatives from tribal government, state agencies, local government, public organizations, and members of the public. The plan is organized into several sections with Chapter 1 providing introductory information such as project location, purpose and need, project goals and objectives, common elements and assumptions, coordination efforts and public scoping, and historical information about the project area. Key …
Date: March 1, 2002
Creator: Childs, Allen B.
Object Type: Report
System: The UNT Digital Library
The Life-cycle of Operons (open access)

The Life-cycle of Operons

Operons are a major feature of all prokaryotic genomes, buthow and why operon structures vary is not well understood. To elucidatethe life-cycle of operons, we compared gene order between Escherichiacoli K12 and its relatives and identified the recently formed anddestroyed operons in E. coli. This allowed us to determine how operonsform, how they become closely spaced, and how they die. Our findingssuggest that operon evolution may be driven by selection on geneexpression patterns. First, both operon creation and operon destructionlead to large changes in gene expression patterns. For example, theremoval of lysA and ruvA from ancestral operons that contained essentialgenes allowed their expression to respond to lysine levels and DNAdamage, respectively. Second, some operons have undergone acceleratedevolution, with multiple new genes being added during a brief period.Third, although genes within operons are usually closely spaced becauseof a neutral bias toward deletion and because of selection against largeoverlaps, genes in highly expressed operons tend to be widely spacedbecause of regulatory fine-tuning by intervening sequences. Althoughoperon evolution may be adaptive, it need not be optimal: new operonsoften comprise functionally unrelated genes that were already inproximity before the operon formed.
Date: March 15, 2007
Creator: Price, Morgan N.; Arkin, Adam P. & Alm, Eric J.
Object Type: Article
System: The UNT Digital Library
Stark Tuning of Donor Electron Spins of Silicon (open access)

Stark Tuning of Donor Electron Spins of Silicon

We report Stark shift measurements for {sup 121}Sb donor electron spins in silicon using pulsed electron spin resonance. Interdigitated metal gates on top of a Sb-implanted {sup 28}Si epi-layer are used to apply electric fields. Two Stark effects are resolved: a decrease of the hyperfine coupling between electron and nuclear spins of the donor and a decrease in electron Zeeman g-factor. The hyperfine term prevails at X-band magnetic fields of 0.35T, while the g-factor term is expected to dominate at higher magnetic fields. A significant linear Stark effect is also resolved presumably arising from strain.
Date: March 23, 2006
Creator: Bradbury, Forrest R.; Tyryshkin, Alexei M.; Sabouret, Guillaume; Bokor, Jeff; Schenkel, Thomas & Lyon, Stephen A.
Object Type: Article
System: The UNT Digital Library
Computational Neutronics Methods and Transmutation Performance Analyses for Fast Reactors (open access)

Computational Neutronics Methods and Transmutation Performance Analyses for Fast Reactors

The once-through fuel cycle strategy in the United States for the past six decades has resulted in an accumulation of Light Water Reactor (LWR) Spent Nuclear Fuel (SNF). This SNF contains considerable amounts of transuranic (TRU) elements that limit the volumetric capacity of the current planned repository strategy. A possible way of maximizing the volumetric utilization of the repository is to separate the TRU from the LWR SNF through a process such as UREX+1a, and convert it into fuel for a fast-spectrum Advanced Burner Reactor (ABR). The key advantage in this scenario is the assumption that recycling of TRU in the ABR (through pyroprocessing or some other approach), along with a low capture-to-fission probability in the fast reactor’s high-energy neutron spectrum, can effectively decrease the decay heat and toxicity of the waste being sent to the repository. The decay heat and toxicity reduction can thus minimize the need for multiple repositories. This report summarizes the work performed by the fuel cycle analysis group at the Idaho National Laboratory (INL) to establish the specific technical capability for performing fast reactor fuel cycle analysis and its application to a high-priority ABR concept. The high-priority ABR conceptual design selected is a metallic-fueled, 1000 …
Date: March 1, 2007
Creator: Ferrer, R.; Asgari, M.; Bays, S. & Forget, B.
Object Type: Report
System: The UNT Digital Library
Evidence for production of single top quarks (open access)

Evidence for production of single top quarks

We present first evidence for the production of single top quarks in the D0 detector at the Fermilab Tevatron p{bar p} collider. The standard model predicts that the electroweak interaction can produce a top quark together with an antibottom quark or light quark, without the antiparticle top quark partner that is always produced from strong coupling processes. Top quarks were first observed in pair production in 1995, and since then, single top quark production has been searched for in ever larger datasets. In this analysis, we select events from a 0.9 fb{sup -1} dataset that have an electron or muon and missing transverse energy from the decay of a W boson from the top quark decay, and two, three, or four jets, with one or two of the jets identified as originating from a b hadron decay. The selected events are mostly backgrounds such as W+jets and t{bar t} events, which we separate from the expected signals using three multivariate analysis techniques: boosted decision trees, Bayesian neural networks, and matrix element calculations. A binned likelihood fit of the signal cross section plus background to the data from the combination of the results from the three analysis methods gives a cross …
Date: March 1, 2008
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type: Article
System: The UNT Digital Library
TRITIUM MOVEMENT AND ACCUMULATION IN THE NGNP SYSTEM INTERFACE AND HYDROGEN PLANT (open access)

TRITIUM MOVEMENT AND ACCUMULATION IN THE NGNP SYSTEM INTERFACE AND HYDROGEN PLANT

Tritium movement and accumulation in the Next Generation Nuclear Plant (NGNP) employing either a high-temperature electrolysis (HTE) process or a thermochemical water-splitting Sulfur-Iodine (SI) process to produce hydrogen is estimated by a numerical code, THYTAN, as a function of design, operational and material parameters. Estimated tritium concentrations in the hydrogen product and in the process chemicals of the hydrogen plant using the HTE process are slightly higher than the limit in drinking water defined by the U.S. Environmental Protection Agency (EPA) and in effluent at the boundary of an unrestricted area defined by the U.S. Nuclear Regulatory Commission (NRC), respectively. Estimated tritium concentrations in the NGNP using the SI hydrogen production process are significantly higher, and are largely affected by undetermined parameters (i.e., tritium permeability of heat exchanger materials, hydrogen concentration in the helium energy transport fluids, equilibrium constant of the tritium isotope exchange reaction between HT and H{sub 2}SO{sub 4}). These parameters should be measured or estimated in the near future, as should the tritium generation and release rate from the NGNP nuclear reactor core. Decreasing the tritium permeation rate between the primary and secondary heat transport circuits is an effective measure to decrease the tritium concentrations in the …
Date: March 20, 2008
Creator: Sherman, S
Object Type: Article
System: The UNT Digital Library
Greening the U.S. House of Representatives (open access)

Greening the U.S. House of Representatives

The Greening the Capitol initiative was launched in March, 2007 with the threefold goals of making the U.S. House of Representatives: 1) carbon neutral within 18 months, 2) reducing energy use by 50percent in ten years, and 3) becoming a model of sustainable operations. We report on the recommendations to meet these goals, looking at the targets of opportunity at the Capitol Power Plant, the existing buildings, and the overall operations of the complex. Our findings have shown that these goals are achievable, and that through an integrated approach the savings in carbon and energy can be met. Specific examples include the lighting retrofits in the House offices, parking areas, and the Capitol dome; the retrofits to the HVAC systems and controls, including duct sealing, improving the efficiency of the energy and water use in the food service areas; and improved operations of the steam and chilled water distribution system. A key aspect has been better tracking and feedback to the building operators of the actual energy consumption. We report on the technical opportunities presented by these historic and symbolic buildings in becoming models of sustainability.
Date: March 1, 2008
Creator: Diamond, Rick; Diamond, Rick & Payne, Christopher
Object Type: Article
System: The UNT Digital Library
Assessment of Crack Detection in Heavy-Walled Cast Stainless Steel Piping Welds Using Advanced Low-Frequency Ultrasonic Methods (open access)

Assessment of Crack Detection in Heavy-Walled Cast Stainless Steel Piping Welds Using Advanced Low-Frequency Ultrasonic Methods

Studies conducted at the Pacific Northwest National Laboratory in Richland, Washington, have focused on assessing the effectiveness and reliability of novel approaches to nondestructive examination (NDE) for inspecting coarse-grained, cast stainless steel reactor components. The primary objective of this work is to provide information to the U.S. Nuclear Regulatory Commission on the effectiveness and reliability of advanced NDE methods as related to the inservice inspection of safety-related components in pressurized water reactors (PWRs). This report provides progress, recent developments, and results from an assessment of low frequency ultrasonic testing (UT) for detection of inside surface-breaking cracks in cast stainless steel reactor piping weldments as applied from the outside surface of the components. Vintage centrifugally cast stainless steel piping segments were examined to assess the capability of low-frequency UT to adequately penetrate challenging microstructures and determine acoustic propagation limitations or conditions that may interfere with reliable flaw detection. In addition, welded specimens containing mechanical and thermal fatigue cracks were examined. The specimens were fabricated using vintage centrifugally cast and statically cast stainless steel materials, which are typical of configurations installed in PWR primary coolant circuits. Ultrasonic studies on the vintage centrifugally cast stainless steel piping segments were conducted with a 400-kHz …
Date: March 1, 2007
Creator: Anderson, Michael T.; Crawford, Susan L.; Cumblidge, Stephen E.; Denslow, Kayte M.; Diaz, Aaron A. & Doctor, Steven R.
Object Type: Report
System: The UNT Digital Library
Flashing Slurry Releases (open access)

Flashing Slurry Releases

The Hanford K Basin Closure Project involves the retrieval, transfer and processing of radioactive contaminated slurries containing partially corroded spent nuclear fuel from the K Basin spent fuel pools. The spent fuel is primarily metallic fuel from the operation of the Hanford reactors. The Sludge Treatment Project is being designed to treat and package this material in preparation for ultimate disposal. The processing of the contaminated slurries includes further corrosion of the remaining uncorroded uranium metal in a large heated vessel to form a more stable metal oxide for packaging and storage.
Date: March 14, 2007
Creator: Schmitt, Bruce E. & Young, Jonathan
Object Type: Article
System: The UNT Digital Library