Domain-wall oscillations studies by time-resolved soft x-ray mircorscopy (open access)

Domain-wall oscillations studies by time-resolved soft x-ray mircorscopy

Fast magnetization dynamics in the micro- and nanometer regime are an interesting field of research. On these length scales magnetic structures can be designed to contain a single vortex or a single domain wall. Both size and speed of these patterns are of great interest in todays research for prospective non-volatile data storage devices. Especially the possibility to move domain-walls by spin-polarized current gained a lot of interest. Magnetic configurations can be imaged by soft X-ray magnetic microscopy with a spatial resolution down to 15 nm. By a stroboscopic pump and probe measurement scheme a temporal resolution below 100 ps is achieved. This provides the opportunity to directly image changes in magnetic domains and domain-wall motion. We image oscillations of a single domain wall in a confining potential in time steps of 200 ps by time resolved X-ray microscopy at the full-field soft X-ray transmission microscope at the Advanced Light Source in Berkeley (beamline 6.1.2). Domain walls are prepared in permalloy nanostructures with a restoring potential. The oscillation of a 180{sup o} domain wall is triggered by nanosecond current pulses. The spin-polarized current and the accompanying Oersted field can contribute to the motion of the wall. By analysis of the …
Date: March 25, 2009
Creator: Bocklage, L.; Kruger, B.; Eiselt, R.; Bolte, M.; Fischer, P. & Meier, G.
Object Type: Article
System: The UNT Digital Library
EMSL Operations Manual (open access)

EMSL Operations Manual

This manual is a general resource tool to assist EMSL users and Laboratory staff within EMSL locate official policy, practice and subject matter experts. It is not intended to replace or amend any formal Battelle policy or practice. Users of this manual should rely only on Battelle’s Standard Based Management System (SBMS) for official policy. No contractual commitment or right of any kind is created by this manual. Battelle management reserves the right to alter, change, or delete any information contained within this manual without prior notice.
Date: March 25, 2009
Creator: Foster, Nancy S.
Object Type: Report
System: The UNT Digital Library
Energy Supply- Production of Fuel from Agricultural and Animal Waste (open access)

Energy Supply- Production of Fuel from Agricultural and Animal Waste

The Society for Energy and Environmental Research (SEER) was funded in March 2004 by the Department of Energy, under grant DE-FG-36-04GO14268, to produce a study, and oversee construction and implementation, for the thermo-chemical production of fuel from agricultural and animal waste. The grant focuses on the Changing World Technologies (CWT) of West Hempstead, NY, thermal conversion process (TCP), which converts animal residues and industrial food processing biproducts into fuels, and as an additional product, fertilizers. A commercial plant was designed and built by CWT, partially using grant funds, in Carthage, Missouri, to process animal residues from a nearby turkey processing plant. The DOE sponsored program consisted of four tasks. These were: Task 1 Optimization of the CWT Plant in Carthage - This task focused on advancing and optimizing the process plant operated by CWT that converts organic waste to fuel and energy. Task 2 Characterize and Validate Fuels Produced by CWT - This task focused on testing of bio-derived hydrocarbon fuels from the Carthage plant in power generating equipment to determine the regulatory compliance of emissions and overall performance of the fuel. Task 3 Characterize Mixed Waste Streams - This task focused on studies performed at Princeton University to better …
Date: March 25, 2009
Creator: Miller, Gabriel
Object Type: Report
System: The UNT Digital Library
Hydrogen Production by Water Dissociation Using Ceramic Membranes - Annual Report for Fy 2008. (open access)

Hydrogen Production by Water Dissociation Using Ceramic Membranes - Annual Report for Fy 2008.

The objective of this project is to develop dense ceramic membranes that, without using an external power supply or circuitry, can produce hydrogen via coal/coal gas-assisted water dissociation. This project grew from an effort to develop a dense ceramic membrane for separating hydrogen from gas mixtures such as those generated during coal gasification, methane partial oxidation, and water-gas shift reactions. That effort led to the development of various cermet (i.e., ceramic/metal composite) membranes that enable hydrogen production by two methods. In one method, a hydrogen transport membrane (HTM) selectively removes hydrogen from a gas mixture by transporting it through either a mixed protonic/electronic conductor or a hydrogen transport metal. In the other method, an oxygen transport membrane (OTM) generates hydrogen mixed with steam by removing oxygen that is generated through water splitting. This project focuses on the development of OTMs that efficiently produce hydrogen via the dissociation of water. Supercritical boilers offer very high-pressure steam that can be decomposed to provide pure hydrogen by means of OTMs. Oxygen resulting from the dissociation of steam can be used for coal gasification, enriched combustion, or synthesis gas production. Hydrogen and sequestration-ready CO{sub 2} can be produced from coal and steam by using …
Date: March 25, 2009
Creator: Balachandran, U.; Dorris, S. E.; Emerson, J. E.; Lee, T. H.; Lu, Y.; Park, C. Y. et al.
Object Type: Report
System: The UNT Digital Library
Identification and Characterization of Hydrogeologic Units at the Nevada Test Site Using Geophysical Logs: Examples from the Underground Test Area Project (open access)

Identification and Characterization of Hydrogeologic Units at the Nevada Test Site Using Geophysical Logs: Examples from the Underground Test Area Project

The diverse and complex geology of the Nevada Test Site region makes for a challenging environment for identifying and characterizing hydrogeologic units penetrated by wells drilled for the U.S. Department of Energy, National Nuclear Security Administration, Underground Test Area (UGTA) Environmental Restoration Sub-Project. Fortunately, UGTA geoscientists have access to large and robust sets of subsurface geologic data, as well as a large historical knowledge base of subsurface geological analyses acquired mainly during the underground nuclear weapons testing program. Of particular importance to the accurate identification and characterization of hydrogeologic units in UGTA boreholes are the data and interpretation principles associated with geophysical well logs. Although most UGTA participants and stakeholders are probably familiar with drill hole data such as drill core and cuttings, they may be less familiar with the use of geophysical logs; this document is meant to serve as a primer on the use of geophysical logs in the UGTA project. Standard geophysical logging tools used in the UGTA project to identify and characterize hydrogeologic units are described, and basic interpretation principles and techniques are explained. Numerous examples of geophysical log data from a variety of hydrogeologic units encountered in UGTA wells are presented to highlight the use …
Date: March 25, 2009
Creator: Lance Prothro, Sigmund Drellack, Margaret Townsend
Object Type: Report
System: The UNT Digital Library
Influence of ammonium availability on expression of nifD and amtB genes during biostimulation of a U(VI) contaminated aquifer: implications for U(VI) removal and monitoring the metabolic state of Geobacteraceae (open access)

Influence of ammonium availability on expression of nifD and amtB genes during biostimulation of a U(VI) contaminated aquifer: implications for U(VI) removal and monitoring the metabolic state of Geobacteraceae

The influence of ammonium availability on bacterial community structure and the physiological status of Geobacter species during in situ bioremediation of uranium-contaminated groundwater was evaluated. Ammonium concentrations varied by 2 orders of magnitude (<4 to 400 ?M) across the study site. Analysis of 16S rRNA sequences suggested that ammonium may have been one factor influencing the community composition prior to acetate amendment with Rhodoferax species predominating over Geobacter species with higher ammonium and Dechloromonas species dominating at the site with lowest ammonium. However, once acetate was added and dissimilatory metal reduction was stimulated, Geobacter species became the predominant organisms at all locations. Rates of U(VI) reduction appeared to be more related to acetate concentrations rather than ammonium levels. In situ mRNA transcript abundance of the nitrogen fixation gene, nifD, and the ammonium transporter gene, amtB, in Geobacter species indicated that ammonium was the primary source of nitrogen during uranium reduction. The abundance of amtB was inversely correlated to ammonium levels, whereas nifD transcript levels were similar across all sites examined. These results suggest that nifD and amtB expression are closely regulated in response to ammonium availability to ensure an adequate supply of nitrogen while conserving cell resources. Thus, quantifying nifD …
Date: March 25, 2009
Creator: Mouser, Paula J.; N'Guessan, A. Lucie; Elifantz, Hila; Holmes, Dawn E.; Williams, Kenneth H; Wilkins, Michael J. et al.
Object Type: Article
System: The UNT Digital Library
JV Task 119 - Effects of Aging on Treated Activated Carbons (open access)

JV Task 119 - Effects of Aging on Treated Activated Carbons

For both the United States and Canada, testing has been under way for electric utilities to find viable and economical mercury control strategies to meet pending future mercury emission limits. The technology that holds the most promise for mercury control in low-chlorine lignite to meet the needs of the Clean Air Act in the United States and the Canada-Wide Standards in Canada is injection of treated activated carbon (AC) into the flue gas stream. Most of the treated carbons are reported to be halogenated, often with bromine. Under a previous multiyear project headed by the Energy & Environmental Research Center (EERC), testing was performed on a slipstream unit using actual lignite-derived flue gas to evaluate various sorbent technologies for their effectiveness, performance, and cost. Testing under this project showed that halogenated ACs performed very well, with mercury capture rates often {ge} 90%. However, differences were noted between treated ACs with respect to reactivity and capacity, possibly as a result of storage conditions. Under certain conditions (primarily storage in ambient air), notable performance degradation had occurred in mercury capture efficiency. Therefore, a small exploratory task within this project evaluated possible differences resulting from storage conditions and subsequent effects of aging that …
Date: March 25, 2009
Creator: Olson, Edwin; Hamre, Lucinda; Pavlish, John & Mibeck, Blaise
Object Type: Report
System: The UNT Digital Library
MODELING THE IMPACT OF ELEVATED MERCURY IN DEFENSE WASTE PROCESSING FACILITY MELTER FEED ON THE MELTER OFF-GAS SYSTEM - PRELIMINARY REPORT (open access)

MODELING THE IMPACT OF ELEVATED MERCURY IN DEFENSE WASTE PROCESSING FACILITY MELTER FEED ON THE MELTER OFF-GAS SYSTEM - PRELIMINARY REPORT

The Defense Waste Processing Facility (DWPF) is currently evaluating an alternative Chemical Process Cell (CPC) flowsheet to increase throughput. It includes removal of the steam-stripping step, which would significantly reduce the CPC processing time and lessen the sampling needs. However, its downside would be to send 100% of the mercury that come in with the sludge straight to the melter. For example, the new mercury content in the Sludge Batch 5 (SB5) melter feed is projected to be 25 times higher than that in the SB4 with nominal steam stripping of mercury. This task was initiated to study the impact of the worst-case scenario of zero-mercury-removal in the CPC on the DWPF melter off-gas system. It is stressed that this study is intended to be scoping in nature, so the results presented in this report are preliminary. In order to study the impact of elevated mercury levels in the feed, it is necessary to be able to predict how mercury would speciate in the melter exhaust under varying melter operating conditions. A homogeneous gas-phase oxidation model of mercury by chloride was developed to do just that. The model contains two critical parameters pertaining to the partitioning of chloride among HCl, …
Date: March 25, 2009
Creator: Zamecnik, J. & Choi, A.
Object Type: Report
System: The UNT Digital Library
Novel Intergrated Process to Process to Produce Fuels from Coal and Other Carbonaceous Feedstocks (open access)

Novel Intergrated Process to Process to Produce Fuels from Coal and Other Carbonaceous Feedstocks

BioConversion Technology, LLC has developed a novel gasifier design that produces a clean, medium to high BTU synthesis gas that can be utilized for a variety of applications. The staged, indirectly heated design produces high quality synthesis gas without the need for costly pure oxygen. This design also allows for extreme flexibility with respect to feedstocks (including those with high moisture contents) in addition to high throughputs in a small gasifier footprint. A pilot scale testing project was proposed to assist BCT with commercializing the process. A prototype gasifier constructed by BCT was transported to WRI for installation and testing. After troubleshooting, the gasifier was successfully operated with both coal and biomass feedstocks. Instrument upgrades are recommended for further testing.
Date: March 25, 2009
Creator: Lucero, Andrew
Object Type: Report
System: The UNT Digital Library
TANK 12 SLUDGE CHARACTERIZATION AND ALUMINUM DISSOLUTION DEMONSTRATION (open access)

TANK 12 SLUDGE CHARACTERIZATION AND ALUMINUM DISSOLUTION DEMONSTRATION

A 3-L sludge slurry sample from Tank 12 was characterized and then processed through an aluminum dissolution demonstration. The dominant constituent of the sludge was found to be aluminum in the form of boehmite. The iron content was minor, about one-tenth that of the aluminum. The salt content of the supernatant was relatively high, with a sodium concentration of {approx}7 M. Due to these characteristics, the yield stress and plastic viscosity of the unprocessed slurry were relatively high (19 Pa and 27 cP), and the settling rate of the sludge was relatively low ({approx}20% settling over a two and a half week period). Prior to performing aluminum dissolution, plutonium and gadolinium were added to the slurry to simulate receipt of plutonium waste from H-Canyon. Aluminum dissolution was performed over a 26 day period at a temperature of 65 C. Approximately 60% of the insoluble aluminum dissolved during the demonstration, with the rate of dissolution slowing significantly by the end of the demonstration period. In contrast, approximately 20% of the plutonium and less than 1% of the gadolinium partitioned to the liquid phase. However, about a third of the liquid phase plutonium became solubilized prior to the dissolution period, when the …
Date: March 25, 2009
Creator: Reboul, S; Michael Hay, M; Kristine Zeigler, K & Michael Stone, M
Object Type: Report
System: The UNT Digital Library
CZT Virtual Frisch-grid Detector: Principles and Applications (open access)

CZT Virtual Frisch-grid Detector: Principles and Applications

Cadmium Zinc Telluride (CdZnTe or CZT) is a very attractive material for using as room-temperature semiconductor detectors, because it has a wide bandgap and a high atomic number. However, due to the material's poor hole mobility, several special techniques were developed to ensure its suitability for radiation detection. Among them, the virtual Frisch-grid CZT detector is an attractive option, having a simple configuration, yet delivering an outstanding spectral performance. The goal of our group in Brookhaven National Laboratory (BNL) is to improve the performance of Frisch-ring CZT detectors; most recently, that effort focused on the non-contacting Frisch-ring detector, allowing us to build an inexpensive, large-volume detector array with high energy-resolution and a large effective area. In this paper, the principles of virtual Frisch-grid detectors are described, especially BNL's innovative improvements. The potential applications of virtual Frisch-grid detectors are discussed, and as an example, a hand-held gamma-ray spectrometer using a CZT virtual Frischgrid detector array is introduced, which is a self-contained device with a radiation detector, readout circuit, communication circuit, and high-voltage supply. It has good energy resolution of 1.4% (FWHM of 662-keV peak) with a total detection volume of {approx}20 cm{sup 3}. Such a portable inexpensive device can be used …
Date: March 24, 2009
Creator: Cui,Y.; Bolotnikov, A.; Camarda, G.; Hossain, A. & James, R. B.
Object Type: Article
System: The UNT Digital Library
A dedicated superbend x-ray microdiffraction beamline for materials, geo-, and environmental sciences at the advanced light source (open access)

A dedicated superbend x-ray microdiffraction beamline for materials, geo-, and environmental sciences at the advanced light source

A new facility for microdiffraction strain measurements and microfluorescence mapping has been built on beamline 12.3.2 at the advanced light source of the Lawrence Berkeley National Laboratory. This beamline benefits from the hard x-radiation generated by a 6 T superconducting bending magnet (superbend) This provides a hard x-ray spectrum from 5 to 22 keV and a flux within a 1 mu m spot of ~;;5x109 photons/ s (0.1percent bandwidth at 8 keV). The radiation is relayed from the superbend source to a focus in the experimental hutch by a toroidal mirror. The focus spot is tailored bytwo pairs of adjustable slits, which serve as secondary source point. Inside the lead hutch, a pair of Kirkpatrick-Baez (KB) mirrors placed in a vacuum tank refocuses the secondary slit source onto the sample position. A new KB-bending mechanism with active temperature stabilization allows for more reproducible and stable mirror bending and thus mirror focusing. Focus spots around 1 um are routinely achieved and allow a variety of experiments, which have in common the need of spatial resolution. The effective spatial resolution (~;;0.2 mu m) is limited by a convolution of beam size, scan-stage resolution, and stage stability. A four-bounce monochromator consisting of two …
Date: March 24, 2009
Creator: Lawrence Berkeley National Laboratory. Advanced Light Source.
Object Type: Article
System: The UNT Digital Library
DOE A9024 Final Report Functional and Nanoscale Materials Systems: Frontier Programs of Science at the Frederick Seitz Materials Research Laboratory (open access)

DOE A9024 Final Report Functional and Nanoscale Materials Systems: Frontier Programs of Science at the Frederick Seitz Materials Research Laboratory

The scientific programs of the FSMRL supported under the DOE A9024 Grant consisted of four interdisciplinary research clusters, as described. The clusters were led by Professors Tai Chiang (Physics), Jeffrey Moore (Chemistry), Paul Goldbart (Physics), and Steven Granick (Materials Science and Engineering). The completed work followed a dominant theme--Nanoscale Materials Systems--and emphasized studies of complex phenomena involving surfaces, interfaces, complex materials, dynamics, energetics, and structures and their transformations. A summary of our key accomplishments is provided for each cluster.
Date: March 24, 2009
Creator: Lewis, Jennifer A.
Object Type: Report
System: The UNT Digital Library
Environmental Management System Plan (open access)

Environmental Management System Plan

Executive Order 13423, Strengthening Federal Environmental, Energy, and Transportation Management establishes the policy that Federal agencies conduct their environmental, transportation, and energy-related activities in a manner that is environmentally, economically and fiscally sound, integrated, continually improving, efficient, and sustainable. The Department of Energy (DOE) has approved DOE Order 450.1A, Environmental Protection Program and DOE Order 430.2B, Departmental Energy, Renewable Energy and Transportation Management as the means of achieving the provisions of this Executive Order. DOE Order 450.1A mandates the development of Environmental Management Systems (EMS) to implement sustainable environmental stewardship practices that: (1) Protect the air, water, land, and other natural and cultural resources potentially impacted by facility operations; (2) Meet or exceed applicable environmental, public health, and resource protection laws and regulations; and (3) Implement cost-effective business practices. In addition, the DOE Order 450.1A mandates that the EMS must be integrated with a facility's Integrated Safety Management System (ISMS) established pursuant to DOE P 450.4, 'Safety Management System Policy'. DOE Order 430.2B mandates an energy management program that considers energy use and renewable energy, water, new and renovated buildings, and vehicle fleet activities. The Order incorporates the provisions of the Energy Policy Act of 2005 and Energy Independence and …
Date: March 24, 2009
Creator: Fox, Robert; Thorson, Patrick; Horst, Blair; Speros, John; Rothermich, Nancy & Hatayama, Howard
Object Type: Report
System: The UNT Digital Library
Harnessing microbial subsurface metal reduction activities to synthesise nanoscale cobalt ferrite with enhanced magnetic properties (open access)

Harnessing microbial subsurface metal reduction activities to synthesise nanoscale cobalt ferrite with enhanced magnetic properties

Nanoscale ferrimagnetic particles have a diverse range of uses from directed cancer therapy and drug delivery systems to magnetic recording media and transducers. Such applications require the production of monodisperse nanoparticles with well-controlled size, composition, and magnetic properties. To fabricate these materials purely using synthetic methods is costly in both environmental and economical terms. However, metal-reducing microorganisms offer an untapped resource to produce these materials. Here, the Fe(III)-reducing bacterium Geobacter sulfurreducens is used to synthesize magnetic iron oxide nanoparticles. A combination of electron microscopy, soft X-ray spectroscopy, and magnetometry techniques was employed to show that this method of biosynthesis results in high yields of crystalline nanoparticles with a narrow size distribution and magnetic properties equal to the best chemically synthesized materials. In particular, it is demonstrated here that cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles with low temperature coercivity approaching 8 kOe and an effective anisotropy constant of {approx} 10{sup 6} erg cm{sup -3} can be manufactured through this biotechnological route. The dramatic enhancement in the magnetic properties of the nanoparticles by the introduction of high quantities of Co into the spinel structure represents a significant advance over previous biomineralization studies in this area using magnetotactic bacteria. The successful production of …
Date: March 24, 2009
Creator: Coker, Victoria S.; Telling, Neil D.; van der Laan, Gerrit; Pattrick, Richard A.D.; Pearce, Carolyn I.; Arenholz, Elke et al.
Object Type: Article
System: The UNT Digital Library
Overview of Results from the National Spherical Torus Experiment (NSTX) (open access)

Overview of Results from the National Spherical Torus Experiment (NSTX)

None
Date: March 24, 2009
Creator: Gates, D. A.; Ahn, J.; Allain, J.; Andre, R.; Bastasz, R.; Bell, M. et al.
Object Type: Report
System: The UNT Digital Library
Point Defect Characterization in CdZnTe (open access)

Point Defect Characterization in CdZnTe

Measurements of the defect levels and performance testing of CdZnTe detectors were performed by means of Current Deep Level Transient Spectroscopy (I-DLTS), Transient Charge Technique (TCT), Current versus Voltage measurements (I-V), and gamma-ray spectroscopy. CdZnTe crystals were acquired from different commercial vendors and characterized for their point defects. I-DLTS studies included measurements of defect parameters such as energy levels in the band gap, carrier capture cross sections, and defect densities. The induced current due to laser-generated carriers was measured using TCT. The data were used to determine the transport properties of the detectors under study. A good correlation was found between the point defects in the detectors and their performance.
Date: March 24, 2009
Creator: Gul, R.; Li, Z.; Bolotnikov, A.; Keeter, K.; Rodriguez, R. & James, R.
Object Type: Article
System: The UNT Digital Library
Post-Closure Inspection Letter Report for Corrective Action Units on the Nevada Test Site (open access)

Post-Closure Inspection Letter Report for Corrective Action Units on the Nevada Test Site

None
Date: March 24, 2009
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
RAPID MEASUREMENTS OF NEPTUNIUM OXIDATION STATES USING CHROMATOGRAPHIC RESINS (open access)

RAPID MEASUREMENTS OF NEPTUNIUM OXIDATION STATES USING CHROMATOGRAPHIC RESINS

The Savannah River Site's (SRS) H-Canyon facility uses ceric ammonium nitrate (CAN) to separate impure neptunium (Np) from a high sulfate feed stream. The material is processed using a two-pass solvent extraction purification which relies on CAN to oxidize neptunium to Np(VI) during the first pass prior to extraction. Spectrophotometric oxidation-state analyses normally used to validate successful oxidation to Np(VI) prior to extraction were compromised by this feed stream matrix. Therefore, a rapid chromatographic method to validate successful Np oxidation was developed using Eichrom Industries TRU and TEVA{reg_sign} resins. The method was validated and subsequently transferred to existing operations in the process analytical laboratories.
Date: March 24, 2009
Creator: Diprete, D; C Diprete, C; Mira Malek, M & Eddie Kyser, E
Object Type: Article
System: The UNT Digital Library
A Spatially Resolving X-ray Crystal Spectrometer for Measurement of Ion-temperature and Rotation-velocity Profiles on the AlcatorC-Mod Tokamak (open access)

A Spatially Resolving X-ray Crystal Spectrometer for Measurement of Ion-temperature and Rotation-velocity Profiles on the AlcatorC-Mod Tokamak

A new spatially resolving x-ray crystal spectrometer capable of measuring continuous spatial profiles of high resolution spectra (λ/dλ > 6000) of He-like and H-like Ar Kα lines with good spatial (~1 cm) and temporal (~10 ms) resolutions has been installed on the Alcator C-Mod tokamak. Two spherically bent crystals image the spectra onto four two-dimensional Pilatus II pixel detectors. Tomographic inversion enables inference of local line emissivity, ion temperature (Ti), and toroidal plasma rotation velocity (vφ) from the line Doppler widths and shifts. The data analysis techniqu
Date: March 24, 2009
Creator: Hill, K. W.; Bitter, M. L.; Scott, S. D.; Ince-Cushman, A.; Reinke, M.; Rice, J. E. et al.
Object Type: Report
System: The UNT Digital Library
Technical Review of Law Enforcement Standards and Guides Relative to Incident Management (open access)

Technical Review of Law Enforcement Standards and Guides Relative to Incident Management

In an effort to locate potential law enforcement-related standards that support incident management, a team from the Pacific Northwest National Laboratory (PNNL) contacted representatives from the National Institute of Standards-Office of Law Enforcement Standards (NIST-OLES), National Institute of Justice (NIJ), Federal Bureau of Investigation (FBI), Secret Service, ASTM International committees that have a law enforcement focus, and a variety of individuals from local and regional law enforcement organizations. Discussions were held with various state and local law enforcement organizations. The NIJ has published several specific equipment-related law enforcement standards that were included in the review, but it appears that law enforcement program and process-type standards are developed principally by organizations that operate at the state and local level. Input is provided from state regulations and codes and from external non-government organizations (NGOs) that provide national standards. The standards that are adopted from external organizations or developed independently by state authorities are available for use by local law enforcement agencies on a voluntary basis. The extent to which they are used depends on the respective jurisdictions involved. In some instances, use of state and local disseminated standards is mandatory, but in most cases, use is voluntary. Usually, the extent to which …
Date: March 24, 2009
Creator: Stenner, Robert D.; Salter, R.; Stanton, J. R. & Fisher, D.
Object Type: Report
System: The UNT Digital Library
Uncertainty Quantification Approaches for Advanced Reactor Analyses. (open access)

Uncertainty Quantification Approaches for Advanced Reactor Analyses.

The original approach to nuclear reactor design or safety analyses was to make very conservative modeling assumptions so as to ensure meeting the required safety margins. Traditional regulation, as established by the U. S. Nuclear Regulatory Commission required conservatisms which have subsequently been shown to be excessive. The commission has therefore moved away from excessively conservative evaluations and has determined best-estimate calculations to be an acceptable alternative to conservative models, provided the best-estimate results are accompanied by an uncertainty evaluation which can demonstrate that, when a set of analysis cases which statistically account for uncertainties of all types are generated, there is a 95% probability that at least 95% of the cases meet the safety margins. To date, nearly all published work addressing uncertainty evaluations of nuclear power plant calculations has focused on light water reactors and on large-break loss-of-coolant accident (LBLOCA) analyses. However, there is nothing in the uncertainty evaluation methodologies that is limited to a specific type of reactor or to specific types of plant scenarios. These same methodologies can be equally well applied to analyses for high-temperature gas-cooled reactors and to liquid metal reactors, and they can be applied to steady-state calculations, operational transients, or severe accident …
Date: March 24, 2009
Creator: Briggs, L. L.
Object Type: Report
System: The UNT Digital Library
Co-ordination of the International Network of Nuclear Structure and Decay Data Evaluators; Summary Report of an IAEA Technical Meeting (open access)

Co-ordination of the International Network of Nuclear Structure and Decay Data Evaluators; Summary Report of an IAEA Technical Meeting

The IAEA Nuclear Data Section convened the 18th meeting of the International Network of Nuclear Structure and Decay Data Evaluators at the IAEA Headquarters, Vienna, 23 to 27 March 2009. This meeting was attended by 22 scientists from 14 Member States, plus IAEA staff, concerned with the compilation, evaluation and dissemination of nuclear structure and decay data. A summary of the meeting, recommendations/conclusions, data centre reports, and various proposals considered, modified and agreed by the participants are contained within this document. The International Network of Nuclear Structure and Decay Data (NSDD) Evaluators holds biennial meetings under the auspices of the IAEA, and consists of evaluation groups and data service centres in several countries. This network has the objective of providing up-to-date nuclear structure and decay data for all known nuclides by evaluating all existing experimental data. Data resulting from this international evaluation collaboration is included in the Evaluated Nuclear Structure Data File (ENSDF) and published in the journals Nuclear Physics A and Nuclear Data Sheets (NDS).
Date: March 23, 2009
Creator: Abriola, D. & Tuli, J.
Object Type: Report
System: The UNT Digital Library
Development of Functionally Graded Materials for Manufacturing Tools and Dies and Industrial Processing Equipment (open access)

Development of Functionally Graded Materials for Manufacturing Tools and Dies and Industrial Processing Equipment

Hot forming processes such as forging, die casting and glass forming require tooling that is subjected to high temperatures during the manufacturing of components. Current tooling is adversely affected by prolonged exposure at high temperatures. Initial studies were conducted to determine the root cause of tool failures in a number of applications. Results show that tool failures vary and depend on the operating environment under which they are used. Major root cause failures include (1) thermal softening, (2) fatigue and (3) tool erosion, all of which are affected by process boundary conditions such as lubrication, cooling, process speed, etc. While thermal management is a key to addressing tooling failures, it was clear that new tooling materials with superior high temperature strength could provide improved manufacturing efficiencies. These efficiencies are based on the use of functionally graded materials (FGM), a new subset of hybrid tools with customizable properties that can be fabricated using advanced powder metallurgy manufacturing technologies. Modeling studies of the various hot forming processes helped identify the effect of key variables such as stress, temperature and cooling rate and aid in the selection of tooling materials for specific applications. To address the problem of high temperature strength, several advanced …
Date: March 23, 2009
Creator: Lherbier, Louis, W.; Novotnak, David, J.; Herling, Darrell, R. & Sears, James, W.
Object Type: Report
System: The UNT Digital Library