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A New Innovative Spherical Cermet Nuclear Fuel Element to Achieve an Ultra-Long Core Life for use in Grid-Appropriate LWRs
Spherical cermet fuel elements are proposed for use in the Atoms For Peace Reactor (AFPR-100) concept. AFPR-100 is a small-scale, inherently safe, proliferation-resistant reactor that would be ideal for deployment to nations with emerging economies that decide to select nuclear power for the generation of carbon-free electricity. The basic concept of the AFPR core is a water-cooled fixed particle bed, randomly packed with spherical fuel elements. The flow of coolant within the particle bed is at such a low rate that the bed does not fluidize. This report summarizes an approach to fuel fabrication, results associated with fuel performance modeling, core neutronics and thermal hydraulics analyses demonstrating a ~20 year core life, and a conclusion that the proliferation resistance of the AFPR reactor concept is high.
Date:
December 1, 2007
Creator:
Senor, David J.; Painter, Chad L.; Geelhood, Ken J.; Wootan, David W.; Meriwether, George H.; Cuta, Judith M. et al.
Object Type:
Report
System:
The UNT Digital Library
Environmentally Benign Stab Detonators
The coupling of energetic metallic multilayers (a.k.a. flash metal) with energetic sol-gel synthesis and processing is an entirely new approach to forming energetic devices for several DoD and DOE needs. They are also practical and commercially viable manufacturing techniques. Improved occupational safety and health, performance, reliability, reproducibility, and environmentally acceptable processing can be achieved using these methodologies and materials. The development and fielding of this technology will enhance mission readiness and reduce the costs, environmental risks and the necessity of resolving environmental concerns related to maintaining military readiness while simultaneously enhancing safety and health. Without sacrificing current performance, we will formulate new impact initiated device (IID) compositions to replace materials from the current composition that pose significant environmental, health, and safety problems associated with functions such as synthesis, material receipt, storage, handling, processing into the composition, reaction products from testing, and safe disposal. To do this, we will advance the use of nanocomposite preparation via the use of multilayer flash metal and sol-gel technologies and apply it to new small IIDs. This work will also serve to demonstrate that these technologies and resultant materials are relevant and practical to a variety of energetic needs of DoD and DOE. The goal …
Date:
July 7, 2006
Creator:
Gash, A. E.
Object Type:
Report
System:
The UNT Digital Library
Control of a high beta maneuvering reentry vehicle using dynamic inversion.
The design of flight control systems for high performance maneuvering reentry vehicles presents a significant challenge to the control systems designer. These vehicles typically have a much higher ballistic coefficient than crewed vehicles like as the Space Shuttle or proposed crew return vehicles such as the X-38. Moreover, the missions of high performance vehicles usually require a steeper reentry flight path angle, followed by a pull-out into level flight. These vehicles then must transit the entire atmosphere and robustly perform the maneuvers required for the mission. The vehicles must also be flown with small static margins in order to perform the required maneuvers, which can result in highly nonlinear aerodynamic characteristics that frequently transition from being aerodynamically stable to unstable as angle of attack increases. The control system design technique of dynamic inversion has been applied successfully to both high performance aircraft and low beta reentry vehicles. The objective of this study was to explore the application of this technique to high performance maneuvering reentry vehicles, including the basic derivation of the dynamic inversion technique, followed by the extension of that technique to the use of tabular trim aerodynamic models in the controller. The dynamic inversion equations are developed for …
Date:
May 1, 2005
Creator:
Watts, Alfred Chapman
Object Type:
Report
System:
The UNT Digital Library
Assessment of Next Generation Nuclear Plant Intermediate Heat Exchanger Design.
The Next Generation Nuclear Plant (NGNP), which is an advanced high temperature gas reactor (HTGR) concept with emphasis on production of both electricity and hydrogen, involves helium as the coolant and a closed-cycle gas turbine for power generation with a core outlet/gas turbine inlet temperature of 900-1000 C. In the indirect cycle system, an intermediate heat exchanger is used to transfer the heat from primary helium from the core to the secondary fluid, which can be helium, nitrogen/helium mixture, or a molten salt. The system concept for the vary high temperature reactor (VHTR) can be a reactor based on the prismatic block of the GT-MHR developed by a consortium led by General Atomics in the U.S. or based on the PBMR design developed by ESKOM of South Africa and British Nuclear Fuels of U.K. This report has made an assessment on the issues pertaining to the intermediate heat exchanger (IHX) for the NGNP. A detailed thermal hydraulic analysis, using models developed at ANL, was performed to calculate heat transfer, temperature distribution, and pressure drop. Two IHX designs namely, shell and straight tube and compact heat exchangers were considered in an earlier assessment. Helical coil heat exchangers were analyzed in the …
Date:
October 17, 2008
Creator:
Majumdar, S.; Moisseytsev, A. & Natesan, K.
Object Type:
Report
System:
The UNT Digital Library
Measurement of Fast Voltage Transients in High-Performance Nb3Sn Magnets
The Superconducting Magnet group at Lawrence Berkeley National Laboratory has been developing Nb{sub 3}Sn high-field accelerator magnet technology for the last fifteen years. In order to support the magnet R&D effort, we are developing a diagnostic system that can help identify the causes of performance limiting quenches by recording small flux-changes within the magnet prior to quench-onset. These analysis techniques were applied to the test results from recent Nb{sub 3}Sn magnets. This paper will examine various types of events and their distinguishing characteristics. The present measurement techniques are discussed along with the design of a new data acquisition system that will substantially improve the quality of the recorded signals.
Date:
June 1, 2008
Creator:
Lietzke, A. F.; Sabbi, G. L.; Ferracin, P.; Caspi, S.; Zimmerman, S.; Joseph, J. et al.
Object Type:
Article
System:
The UNT Digital Library
New American Home 2009 (Brochure)
This brochure details the New American Home 2009, which demonstrates the use of innovative building materials, cutting-edge design, and the latest construction techniques.
Date:
December 1, 2008
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Mechanical and charge transport properties of alkanethiol self-assembled monolayers on Au (111) surface: The Role of Molecular Tilt
The relationship between charge transport and mechanical properties of alkanethiol self-assembled monolayers (SAM) on Au(111) films has been investigated using an atomic force microscope with a conductive tip. Molecular tilts induced by the pressure applied by the tip cause stepwise increases in film conductivity. A decay constant {beta} = 0.57 {+-} 0.03 {angstrom}{sup -1} was found for the current passing through the film as a function of tip-substrate separation due to this molecular tilt. This is significantly smaller than the value of {approx} 1 {angstrom}{sup -1} found when the separation is changed by changing the length of the alkanethiol molecules. Calculations indicate that for isolated dithiol molecules S-bonded to hollow sites, the junction conductance does not vary significantly as a function of molecular tilt. The impact of S-Au bonding on SAM conductance is discussed.
Date:
November 12, 2007
Creator:
Mulleregan, Alice; Qi, Yabing; Ratera, Imma; Park, Jeong Y.; Ashby, Paul D.; Quek, Su Ying et al.
Object Type:
Article
System:
The UNT Digital Library
THz radiation as a bunch diagnostic forlaser-wakefield-accelerated electron bunches
Experimental results are reported from two measurementtechniques (semiconductor switching and electro-optic sampling) thatallow temporal characterization of electron bunches produced by alaser-driven plasma-based accelerator. As femtosecond electron bunchesexit the plasma-vacuum interface, coherent transition radiation (at THzfrequencies) is emitted. Measuring the properties of this radiationallows characterization of the electron bunches. Theoretical work on theemission mechanism is represented, including a model that calculates theTHz waveform from a given bunch profile. It is found that the spectrum ofthe THz pulse is coherent up to the 200 mu m thick crystal (ZnTe)detection limit of 4 THz, which corresponds to the production of sub-50fs (root-mean-square) electron bunch structure. The measurementsdemonstrate both the shot-to-shot stability of bunch parameters that arecritical to THz emission (such as total charge and bunch length), as wellas femtosecond synchrotron between bunch, THz pulse, and laserbeam.
Date:
February 15, 2006
Creator:
van Tilborg, J.; Schroeder, C. B.; Filip, C. V.; Toth, Cs.; Geddes, C. G. R.; Fubiani, G. et al.
Object Type:
Article
System:
The UNT Digital Library
Solar Advisor Model User Guide for Version 2.0
The Solar Advisor Model (SAM) provides a consistent framework for analyzing and comparing power system costs and performance across the range of solar technologies and markets, from photovoltaic systems for residential and commercial markets to concentrating solar power and large photovoltaic systems for utility markets. This manual describes Version 2.0 of the software, which can model photovoltaic and concentrating solar power technologies for electric applications for several markets. The current version of the Solar Advisor Model does not model solar heating and lighting technologies.
Date:
August 1, 2008
Creator:
Gilman, P.; Blair, N.; Mehos, M.; Christensen, C.; Janzou, S. & Cameron, C.
Object Type:
Report
System:
The UNT Digital Library
Initial Operation of the High Temperature Electrolysis Integrated Laboratory Scale Experiment at INL
An integrated laboratory scale, 15 kW high-temperature electrolysis facility has been developed at the Idaho National Laboratory under the U.S. Department of Energy Nuclear Hydrogen Initiative. Initial operation of this facility resulted in over 400 hours of operation with an average hydrogen production rate of approximately 0.9 Nm3/hr. The integrated laboratory scale facility is designed to address larger-scale issues such as thermal management (feed-stock heating, high-temperature gas handling), multiple-stack hot-zone design, multiple-stack electrical configurations, and other “integral” issues. This paper documents the initial operation of the ILS, with experimental details about heat-up, initial stack performance, as well as long-term operation and stack degradation.
Date:
June 1, 2008
Creator:
Stoots, C. M.; O'Brien, J. E.; Condie, K. G.; Herring, J. S. & Hartvigsen, J. J.
Object Type:
Article
System:
The UNT Digital Library
Radiation Doses to Hanford Workers from Natural Potassium-40
The chemical element potassium is an essential mineral in people and is subject to homeostatic regulation. Natural potassium comprises three isotopes, 39K, 40K, and 41K. Potassium-40 is radioactive, with a half life of 1.248 billion years. In most transitions, it emits a β particle with a maximum energy of 0.560 MeV, and sometimes a gamma photon of 1.461 MeV. Because it is ubiquitous, 40K produces radiation dose to all human beings. This report contains the results of new measurements of 40K in 248 adult females and 2,037 adult males performed at the Department of Energy Hanford Site in 2006 and 2007. Potassium concentrations diminish with age, are generally lower in women than in men, and decrease with body mass index (BMI). The average annual effective dose from 40K in the body is 0.149 mSv y−1 for men and 0.123 mSv y−1 women respectively. Averaged over both men and women, the average effective dose per year is 0.136 mSv y−1. Calculated effective doses range from 0.069 to 0.243 mSv y−1 for adult males, and 0.067 to 0.203 mSv y−1 for adult females, a roughly three-fold variation for each gender. The need for dosimetric phantoms with a greater variety of BMI values …
Date:
February 13, 2009
Creator:
Strom, Daniel J.; Lynch, Timothy P. & Weier, Dennis R.
Object Type:
Report
System:
The UNT Digital Library
Transmission Electron Microscopy Study of Nonpolar a-Plane GaNGrown by Pendeo-Epitaxy on (112_0) 4H-SiC
Pendeo-epitaxy has been applied to nonpolar a-plane GaN layers in order to observe if such process will lead to defect reduction in comparison with direct growth on this plane. Uncoalesced and coalesced a-plane GaN layers with thicknesses 2{micro}m and 12{micro}m, respectively have been studied by conventional and high resolution electron microscopy. The following structural defects have been observed in pendeo-epitaxial layers: (1) basal stacking faults, (2) threading dislocations and (3) prismatic stacking faults. Drastic decrease of threading dislocation density and stacking faults have been observed in 'wing' areas with respect to 'seed' areas. Cross-section images reveal cracks and voids at the areas where two coalesced wings meet each other. High resolution electron microscopy shows that the majority of stacking faults are low-energy planar defects of the types I{sub 1}, I{sub 2} and I{sub 3}. The I{sub 3} type basal stacking fault, predicted theoretically, has been observed experimentally for the first time.
Date:
March 10, 2005
Creator:
Zakharov, D. N.; Liliental-Weber, Z.; Wagner, B.; Reitmeier, Z. J.; Preble, E. A. & Davis, R. F.
Object Type:
Article
System:
The UNT Digital Library
GNEP ? Material Transportation, Storage & Disposal Analysis FY-07 Summary Report
None
Date:
October 4, 2007
Creator:
Halsey, W.; Wigeland, R.; Nutt, M.; Bauer, T.; Smith, J. D.; Sorensen, K. et al.
Object Type:
Report
System:
The UNT Digital Library
Three-dimensional lithographically-defined organotypic tissue arrays for quantitative analysis of morphogenesis and neoplastic progression
Here we describe a simple micromolding method to construct three-dimensional arrays of organotypic epithelial tissue structures that approximate in vivo histology. An elastomeric stamp containing an array of posts of defined geometry and spacing is used to mold microscale cavities into the surface of type I collagen gels. Epithelial cells are seeded into the cavities and covered with a second layer of collagen. The cells reorganize into hollow tissues corresponding to the geometry of the cavities. Patterned tissue arrays can be produced in 3-4 h and will undergo morphogenesis over the following one to three days. The protocol can easily be adapted to study a variety of tissues and aspects of normal and neoplastic development.
Date:
February 13, 2008
Creator:
Nelson, Celeste M.; Inman, Jamie L. & Bissell, Mina J.
Object Type:
Article
System:
The UNT Digital Library
Z' Coupling Information From LHeC
None
Date:
April 4, 2008
Creator:
Rizzo, Thomas G.
Object Type:
Article
System:
The UNT Digital Library
Real Time Dynamics of Laser Activated Interface Processes at the Molecular Scale
Nanotechnology is one of the most interesting and challenging frontiers of science and technology. We are motivated by the belief that progress will come from improved understanding and control of structure, dynamics and reactivity at interfaces. First, we provide a summary of our projects and key findings. The following pages provide a more detailed account.
Date:
December 30, 2007
Creator:
Borguet, Eric
Object Type:
Report
System:
The UNT Digital Library
R. Bruce Merrifield and Solid-Phase Peptide Synthesis: A Historical Assessment
Bruce Merrifield, trained as a biochemist, had to address three major challenges related to the development and acceptance of solid-phase peptide synthesis (SPPS). The challenges were (1) to reduce the concept of peptide synthesis on a insoluble support to practice, (2) overcome the resistance of synthetic chemists to this novel approach, and (3) establish that a biochemist had the scientific credentials to effect the proposed revolutionary change in chemical synthesis. How these challenges were met is discussed in this article.
Date:
December 4, 2007
Creator:
Mitchell, A R
Object Type:
Article
System:
The UNT Digital Library
Solar Advisor Model; Session: Modeling and Analysis
This project supports the Solar America Initiative by: (1) providing a consistent framework for analyzing and comparing power system costs and performance across the range of solar technologies and markets, PV, solar heat systems, CSP, residential, commercial and utility markets; (2) developing and validating performance models to enable accurate calculation of levelized cost of energy (LCOE); (3) providing a consistent modeling platform for all TPP's; and (4) supporting implementation and usage of cost models.
Date:
April 1, 2008
Creator:
Blair, N.
Object Type:
Presentation
System:
The UNT Digital Library
Strategic Plan for Sustainable Energy Management and Environmental Stewardship for Los Angeles Unified School District
This Strategic Plan for Sustainable Energy Management and Environmental Stewardship states goals, measures progress toward goals and how actions are monitored to achieve continuous improvement for the Los Angeles Unified School District.
Date:
November 1, 2007
Creator:
Walker, A.; Beattie, D.; Thomas, K.; Davis, K.; Sim, M. & Jhaveri, A.
Object Type:
Report
System:
The UNT Digital Library
Superconducting solenoids for an international muon coolingexperiment
None
Date:
August 3, 2002
Creator:
Green, M.A. & Rey, J.M.
Object Type:
Article
System:
The UNT Digital Library
State-of-the-Art Beta Detection and Dosimetry
The research funded by this NEER grant establishes the framework for a detailed understanding of the challenges in beta dosimetry, especially in the presence of a mixed radiation field. The work also stimulated the thinking of the research group which will lead to new concepts in digital signal processing to allow collection of detection signals and real-time analysis such that simultaneous beta and gamma spectroscopy can take place. The work described herein (with detail in the many publications that came out of this research) was conducted in a manner that provided dissertation and thesis topics for three students, one of whom was completely funded by this grant. The overall benefit of the work came in the form of a dramatic shift in signal processing that is normally conducted in analog pulse shape analysis. Analog signal processing was shown not to be feasible for this type of work; digital signal processing was a must. This, in turn, led the research team to a new understanding of pulse analysis, one in which expands the state-of-the-art in simultaneous beta and gamma spectroscopy with a single detector.
Date:
August 15, 2008
Creator:
Hamby, David M.
Object Type:
Report
System:
The UNT Digital Library
LLNL Facility Screening Report (SCR) for B362
None
Date:
September 14, 2007
Creator:
Cooper, G
Object Type:
Report
System:
The UNT Digital Library
Differentiating neutrino models on the basis of $\theta_{13}$ and lepton flavor violation
The authors show how models of neutrino masses and mixings can be differentiated on the basis of their predictions for {theta}{sub 13} and lepton flavor violation in radiative charged lepton decays and {mu} - e conversion. They illustrate the lepton flavor violation results for five predictive SO(10) SUSY GUT models and point out the relative importance of their heavy right-handed neutrino mass spectra and {theta}{sub 13} predictions.
Date:
March 1, 2008
Creator:
Albright, Carl H.
Object Type:
Article
System:
The UNT Digital Library
Resonant Soft X-Ray Contrast Variation Methods as Composition-Specific Probes of Thin Polymer Film Structure
We have developed complementary soft x-ray scattering and reflectometry techniques that allow for the morphological analysis of thin polymer films without resorting to chemical modification or isotopic 2 labeling. With these techniques, we achieve significant, x-ray energy-dependent contrast between carbon atoms in different chemical environments using soft x-ray resonance at the carbon edge. Because carbon-containing samples absorb strongly in this region, the scattering length density depends on both the real and imaginary parts of the atomic scattering factors. Using a model polymer film of poly(styrene-b-methyl methacrylate), we show that the soft x-ray reflectivity data is much more sensitive to these atomic scattering factors than the soft x-ray scattering data. Nevertheless, fits to both types of data yield useful morphological details on the polymer?slamellar structure that are consistent with each other and with literature values.
Date:
April 4, 2008
Creator:
Welch, Cynthia; Welch, Cynthia F.; Hjelm, Rex P.; Mang, Joseph T.; Hawley, Marilyn E.; Wrobleski, Debra A. et al.
Object Type:
Article
System:
The UNT Digital Library