Ductility Characterization of U-6Nb and Ta-W Alloys (open access)

Ductility Characterization of U-6Nb and Ta-W Alloys

We have previously evaluated the ductility behaviors of U-6Nb and pure Ta. One important observation was that both alloys have very stable necking ductility independent of test conditions. In contrast, uniform ductility varied significantly depending upon strain rates and temperatures. In general, higher strain rate and lower temperature reduce the uniform ductility. Using literature data, we have developed two dynamic ductility models to predict the ductility behaviors of pure-Ta and water-quenched U-6Nb respectively under extreme conditions. In this study we further evaluate the aging effect on U-6Nb and the W-addition effect on Ta. For U-6Nb, the objective is to determine whether or not the ductility degradation by low-temperature aging mostly measured in quasi-static condition can still be observed under dynamic loading (high strain rate) condition. For Ta-W alloys, the focus is to identify the key control parameter so that the optimal condition of high-strength/high-ductility of Ta-10W can be achieved for certain defense-related applications.
Date: September 15, 2006
Creator: Sun, T & Cervantes, O
Object Type: Article
System: The UNT Digital Library
Development of Historical Water Table Maps of the 200 West Area of the Hanford Site (1950-1970) (open access)

Development of Historical Water Table Maps of the 200 West Area of the Hanford Site (1950-1970)

A series of detailed historical water-table maps for the 200-West Area of the Hanford Site was made to aid interpretation of contaminant distribution in the upper aquifer. The contaminants are the result of disposal of large volumes of waste to the ground during Hanford Site operations, which began in 1944 and continued into the mid-1990s. Examination of the contaminant plumes that currently exist on site shows that the groundwater beneath the 200-West Area has deviated from its pre-Hanford west-to-east flow direction during the past 50 years. By using historical water-level measurements from wells around the 200-West Area, it was possible to create water-table contour maps that show probable historic flow directions. These maps are more detailed than previously published water-table maps that encompass the entire Hanford Site.
Date: September 15, 2006
Creator: Kinney, Teena M. & McDonald, John P.
Object Type: Report
System: The UNT Digital Library
Preliminary Safety Evaluation of the Advanced Burner Test Reactor. (open access)

Preliminary Safety Evaluation of the Advanced Burner Test Reactor.

Results of a preliminary safety evaluation of the Advanced Burner Test Reactor (ABTR) pre-conceptual design are reported. The ABTR safety design approach is described. Traditional defense-in-depth design features are supplemented with passive safety performance characteristics that include natural circulation emergency decay heat removal and reactor power reduction by inherent reactivity feedbacks in accidents. ABTR safety performance in design-basis and beyond-design-basis accident sequences is estimated based on analyses. Modeling assumptions and input data for safety analyses are presented. Analysis results for simulation of simultaneous loss of coolant pumping power and normal heat rejection are presented and discussed, both for the case with reactor scram and the case without reactor scram. The analysis results indicate that the ABTR pre-conceptual design is capable of undergoing bounding design-basis and beyond-design-basis accidents without fuel cladding failures. The first line of defense for protection of the public against release of radioactivity in accidents remains intact with significant margin. A comparison and evaluation of general safety design criteria for the ABTR conceptual design phase are presented in an appendix. A second appendix presents SASSYS-1 computer code capabilities and modeling enhancements implemented for ABTR analyses.
Date: September 15, 2006
Creator: Dunn, F. E.; Fanning, T. H. & Cahalan, J. E.
Object Type: Report
System: The UNT Digital Library
Fluctuations and Gibbs-Thomson Law - the Simple Physics. (open access)

Fluctuations and Gibbs-Thomson Law - the Simple Physics.

Crystals of slightly soluble materials should be subject of relatively weak attachment/detachment fluctuations on their faces so that steps on that faces have low kink density. These steps are parallel to the most close packed lattice rows and form polygons on a crystal surface. The process responsible for implementation of the classical Gibbs-Thomson law (GTL) for the polygonal step (in two dimensions, 2D) is kink exchange between the step corners. For the 3D crystallites, this mechanism includes step exchange. If these mechanisms do not operate because of slow fluctuations the GTL is not applicable. Physics of these processes and conditions for the GTL applicability are discussed on a simple qualitative level.
Date: September 15, 2006
Creator: Chernov, A. A.; De Yoreo, J. J. & Rashkovich, L. N.
Object Type: Article
System: The UNT Digital Library
CH-TRU Waste Content Codes (CH-TRUCON) (open access)

CH-TRU Waste Content Codes (CH-TRUCON)

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container. Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 …
Date: September 15, 2006
Creator: Westinghouse TRU Solutions LLC
Object Type: Report
System: The UNT Digital Library
Installation of 200 kW UTC PC-25 Natural Gas Fuel Cell At City of Anaheim Police Station (open access)

Installation of 200 kW UTC PC-25 Natural Gas Fuel Cell At City of Anaheim Police Station

The City of Anaheim Public Utilities Department (Anaheim) has been providing electric service to Anaheim residents and businesses for over a century. As a city in a high-growth region, identifying sources of reliable energy to meet demand is a constant requirement. Additionally, as more power generation is needed, locating generating stations locally is a difficult proposition and must consider environmental and community impacts. Anaheim believes benefits can be achieved by implementing new distributed generation technologies to supplement central plants, helping keep pace with growing demand for power. If the power is clean, then it can be delivered with minimal environmental impact. Anaheim started investigating fuel cell technology in 2000 and decided a field demonstration of a fuel cell power plant would help determine how the technology can best serve Anaheim. As a result, Anaheim completed the project under this grant as a way to gain installation and operating experience about fuel cells and fuel cell capabilities. Anaheim also hopes to help others learn more about fuel cells by providing information about this project to the public. Currently, Anaheim has hosted a number of requested tours at the project site, and information about the project can be found on Anaheim Public …
Date: September 15, 2006
Creator: Predisik, Dina
Object Type: Report
System: The UNT Digital Library
Fuel Cell Demonstration Program - Central and Remote Sites 2003 (open access)

Fuel Cell Demonstration Program - Central and Remote Sites 2003

In an effort to promote clean energy projects and aid in the commercialization of new fuel cell technologies, the Long Island Power Authority (LIPA) initiated a Fuel Cell Demonstration Program in 1999 with six month deployments of Proton Exchange Membrane (PEM) non-commercial Beta model systems at partnering sites throughout Long Island. These projects facilitated significant developments in the technology, providing operating experience that allowed the manufacturer to produce fuel cells that were half the size of the Beta units and suitable for outdoor installations. In 2001, LIPA embarked on a large-scale effort to identify and develop measures that could improve the reliability and performance of future fuel cell technologies for electric utility applications and the concept to establish a fuel cell farm (Farm) of 75 units was developed. By the end of October of 2001, 75 Lorax 2.0 fuel cells had been installed at the West Babylon substation on Long Island, making it the first fuel cell demonstration of its kind and size anywhere in the world at the time. Designed to help LIPA study the feasibility of using fuel cells to operate in parallel with LIPA's electric grid system, the Farm operated 120 fuel cells over its lifetime of …
Date: September 15, 2006
Creator: Brun, Gerald
Object Type: Report
System: The UNT Digital Library
Perrhenate and Pertechnetate Behavior on Iron and Sulfur-Bearing Compounds. (open access)

Perrhenate and Pertechnetate Behavior on Iron and Sulfur-Bearing Compounds.

Investigations on the behavior of the radioactive element technetium frequently use a stable isotope of rhenium as an analogue. This is justified by citing the elements similar radii and major oxidation states of +7 and +4. However, at least one study [1] has shown this analogy to be imperfect. Therefore, one goal of our study is to compare the adsorption behavior of perrhenate and pertechnetate (the major forms of Re and Tc in natural waters) on a number of different mineral surfaces. Quantum mechanical calculations were performed on the adsorption of these two anions on a series of iron oxides and sulfides. With these calculations, we gain insight into any differences between the anions adsorption behavior, including geometry, adsorption energies, and electronic structure such as density of states and orbital shapes and energies at the adsorption site. Differences between interactions on terraces and step edges, the effects of co-adsorbates such as Na{sup +} or H{sup +}, and possible reduction mechanisms are also explored. The influence of water was calculated using homogeneous dielectric fluids and explicit water molecules. As a complement to the calculations, batch sorption tests are in progress involving ReO{sub 4}{sup -}/TcO{sub 4}{sup -} solution in contact with Fe …
Date: September 15, 2006
Creator: Anderson, B. E.; Becker, U.; Helean, K. B. & Ewing, R. C.
Object Type: Report
System: The UNT Digital Library
Characterization of Suspect Fuel Rod Pieces from the 105 K West Basin (open access)

Characterization of Suspect Fuel Rod Pieces from the 105 K West Basin

This report provides physical and radiochemical characterization results from examinations and laboratory analyses performed on ~0.55-inch diameter rod pieces found in the 105 K West (KW) Basin that were suspected to be from nuclear reactor fuel. The characterization results will be used to establish the technical basis for adding this material to the contents of one of the final Multi-Canister Overpacks (MCOs) that will be loaded out of the KW Basin in late FY2006 or at a later time depending on project priorities. Fifteen fuel rod pieces were found during the clean out of the KW Basin. Based on lack of specific credentials, documentation, or obvious serial numbers, none of the items could be positively identified nor could their sources or compositions be described. Item weights and dimensions measured in the KW Basin indicated densities consistent with the suspect fuel rods containing uranium dioxide (UO2), uranium metal, or being empty. Extensive review of the Hanford Site technical literature led to the postulation that these pieces likely were irradiated test fuel prepared to support of the development of the Hanford “New Production Reactor,” later called N Reactor. To obtain definitive data on the composition of the suspect fuel, 4 representative fuel …
Date: September 15, 2006
Creator: Delegard, Calvin H.; Schmidt, Andrew J.; Pool, Karl N. & Thornton, Brenda M.
Object Type: Report
System: The UNT Digital Library
A Five-Level Cascade Multilever Invertor Three-Phase Motor Drive Using a Single DC Source (open access)

A Five-Level Cascade Multilever Invertor Three-Phase Motor Drive Using a Single DC Source

A method is presented showing that a 5-level cascade multilevel inverter for a three-phase permanent magnet synchronous motor drive can be implemented using only a single DC link to supply a standard 3-leg inverter along with three full H-bridges supplied by capacitors. It is shown that the capacitor voltages can be regulated while achieving an output voltage waveform that is 20% greater than that obtained using the standard 3-leg inverter alone. Finally conditions are given in terms of the power factor and modulation index that determine when the capacitor voltage can regulated.
Date: September 15, 2006
Creator: Chiasson, J.N. (Univ. Tennessee-Knoxville)
Object Type: Report
System: The UNT Digital Library
CHARACTERIZATION TESTING AND ANALYSIS OF SINGLE CELL SO2 DEPOLARIZED ELECTROLYZER (open access)

CHARACTERIZATION TESTING AND ANALYSIS OF SINGLE CELL SO2 DEPOLARIZED ELECTROLYZER

This document reports work performed at the Savannah River National Laboratory (SRNL) that further develops the use of a proton exchange membrane or PEM-type electrochemical cell to produce hydrogen via SO{sub 2}-depolarized water electrolysis. This work was begun at SRNL in 2005. This research is valuable in achieving the ultimate goal of an economical hydrogen production process based on the Hybrid Sulfur (HyS) Cycle. The HyS Process is a hybrid thermochemical cycle that may be used in conjunction with advanced nuclear reactors or centralized solar receivers to produce hydrogen by water-splitting. Like all other sulfur-based cycles, HyS utilizes the high temperature thermal decomposition of sulfuric acid to produce oxygen. The unique aspect of HyS is the generation of hydrogen in a water electrolyzer that is operated under conditions where dissolved sulfur dioxide depolarizes the anodic reaction, resulting in substantial voltage reduction. Sulfur dioxide is oxidized at the anode, producing sulfuric acid that is sent to the acid decomposition portion of the cycle. The focus of this work was to conduct single cell electrolyzer tests in order to prove the concept of SO{sub 2}-depolarization and to determine how the results can be used to evaluate the performance of key components of …
Date: September 15, 2006
Creator: Steimke, J & Timothy Steeper, T
Object Type: Report
System: The UNT Digital Library
Pysico-chemical properties of hydrophobic ionic liquids containing1-octylpyridinium, 1-octyl-2-methylpyridinium or1-octyl-4-methylpyridinium cations (open access)

Pysico-chemical properties of hydrophobic ionic liquids containing1-octylpyridinium, 1-octyl-2-methylpyridinium or1-octyl-4-methylpyridinium cations

This paper reports synthesis of some ionic liquids based on cations 1-octylpyridinium, 1-octyl-2-methylpyridinium or 1-octyl-4-methylpyridinium and anions dicyanamide [N(CN)2]-, bis(trifluoromethylsulfonyl)imide [Tf2N]-, bis(pentafluoroethylsulfonyl)imide [BETI]-, trifluoromethyl sulfonate [TfO]-, nonafluorobutyl sulfonate [NfO]-, tetrafluoroborate [BF4]-, trifluorophenylborate [BF3Ph]- or hexafluoroarsenate [AsF6]-. Melting points, decomposition temperatures, densities, mutual solubilities with water, and viscosities have been measured. Unlike similar ionic liquids containing imidazolium cations, pyridinium ionic liquids studied here are nearly immiscible in water. Viscosities are similar and water content is slightly lower than those for ionic liquids containing imidazolium cations.
Date: September 15, 2006
Creator: Papaiconomou, Nicolas; Salminen, Justin; Lee, Jong-Min & Prausnitz, John M.
Object Type: Article
System: The UNT Digital Library
Climate Change Fuel Cell Program (open access)

Climate Change Fuel Cell Program

A 200 kW, natural gas fired fuel cell was installed at the Richard Stockton College of New Jersey. The purpose of this project was to demonstrate the financial and operational suitability of retrofit fuel cell technology at a medium sized college. Target audience was design professionals and the wider community, with emphasis on use in higher education. ''Waste'' heat from the fuel cell was utilized to supplement boiler operations and provide domestic hot water. Instrumentation was installed in order to measure the effectiveness of heat utilization. It was determined that 26% of the available heat was captured during the first year of operation. The economics of the fuel cell is highly dependent on the prices of electricity and natural gas. Considering only fuel consumed and energy produced (adjusted for boiler efficiency), the fuel cell saved $54,000 in its first year of operation. However, taking into account the price of maintenance and the cost of financing over the short five-year life span, the fuel cell operated at a loss, despite generous subsidies. As an educational tool and market stimulus, the fuel cell attracted considerable attention, both from design professionals and the general public.
Date: September 15, 2006
Creator: Gitchell, Alice M.
Object Type: Report
System: The UNT Digital Library
An Integrated Hydrogen Production-CO2 Capture Process from Fossil Fuel (open access)

An Integrated Hydrogen Production-CO2 Capture Process from Fossil Fuel

None
Date: September 15, 2006
Creator: Wang, Z. & Bota, K. B.
Object Type: Report
System: The UNT Digital Library
DoD Climate Change Fuel Cell Program (open access)

DoD Climate Change Fuel Cell Program

This report discusses the first year of operation of a fuel cell power plant located at the Ocean County College, Toms River, New Jersey. PPL EnergyPlus, LLC installed the plant under a contract with Ocean County College. A DFC{reg_sign}300 fuel cell, manufactured by Fuel Cell Energy, Inc. of Danbury, CT was selected for the project. The fuel cell successfully operated from January 1, 2004 to December 31, 2004. This report discusses the performance of the plant during this period. Ocean County College's decision to contract for use of a fuel cell at the college reflects the institution's commitment to managing energy costs, exercising environmental leadership, and leveraging innovative technologies to accomplish its energy and environmental goals. Ocean County College's director of facilities was interested in finding new energy cost reduction opportunities that could build on the institution's growing reputation for commitment to energy efficiency and environmental quality while exploring new technologies. This combination of goals positioned Ocean County College to value the prospect of installing a fuel cell as a demonstration project that could deliver on its commitment. PPL EnergyPlus, LLC developed the project and Millennium Builders, a PPL company, was chosen as the general contractor for the project. PPL …
Date: September 15, 2006
Creator: Olsen, Ken
Object Type: Report
System: The UNT Digital Library
Fuel Cell Demonstration Program (open access)

Fuel Cell Demonstration Program

In an effort to promote clean energy projects and aid in the commercialization of new fuel cell technologies the Long Island Power Authority (LIPA) initiated a Fuel Cell Demonstration Program in 1999 with six month deployments of Proton Exchange Membrane (PEM) non-commercial Beta model systems at partnering sites throughout Long Island. These projects facilitated significant developments in the technology, providing operating experience that allowed the manufacturer to produce fuel cells that were half the size of the Beta units and suitable for outdoor installations. In 2001, LIPA embarked on a large-scale effort to identify and develop measures that could improve the reliability and performance of future fuel cell technologies for electric utility applications and the concept to establish a fuel cell farm (Farm) of 75 units was developed. By the end of October of 2001, 75 Lorax 2.0 fuel cells had been installed at the West Babylon substation on Long Island, making it the first fuel cell demonstration of its kind and size anywhere in the world at the time. Designed to help LIPA study the feasibility of using fuel cells to operate in parallel with LIPA's electric grid system, the Farm operated 120 fuel cells over its lifetime of …
Date: September 15, 2006
Creator: Brun, Gerald
Object Type: Report
System: The UNT Digital Library
Inhibition of TGFbeta1 Signaling Attenutates ATM Activity inResponse to Genotoxic Stress (open access)

Inhibition of TGFbeta1 Signaling Attenutates ATM Activity inResponse to Genotoxic Stress

Ionizing radiation causes DNA damage that elicits a cellular program of damage control coordinated by the kinase activity of ataxia telangiectasia mutated protein (ATM). Transforming growth factor {beta}1 (TGF{beta}), which is activated by radiation, is a potent and pleiotropic mediator of physiological and pathological processes. Here we show that TGF{beta} inhibition impedes the canonical cellular DNA damage stress response. Irradiated Tgf{beta}1 null murine epithelial cells or human epithelial cells treated with a small molecule inhibitor of TGF{beta} type I receptor kinase exhibit decreased phosphorylation of Chk2, Rad17 and p53, reduced {gamma}H2AX radiation-induced foci, and increased radiosensitivity compared to TGF{beta} competent cells. We determined that loss of TGF{beta} signaling in epithelial cells truncated ATM autophosphorylation and significantly reduced its kinase activity, without affecting protein abundance. Addition of TGF{beta} restored functional ATM and downstream DNA damage responses. These data reveal a heretofore undetected critical link between the microenvironment and ATM that directs epithelial cell stress responses, cell fate and tissue integrity. Thus, TGF{beta}1, in addition to its role in homoeostatic growth control, plays a complex role in regulating responses to genotoxic stress, the failure of which would contribute to the development of cancer; conversely, inhibiting TGF{beta} may be used to advantage in …
Date: September 15, 2006
Creator: Kirshner, Julia; Jobling, Michael F.; Pajares, Maria Jose; Ravani, Shraddha A.; Glick, Adam B.; Lavin, Martin J. et al.
Object Type: Article
System: The UNT Digital Library
Appendix A; Appendix B (open access)

Appendix A; Appendix B

This is the summary page for the technical and other reports on the DOE Cooperative Agreement DE-FC36-94CH10604 for the period of January 1, 2000 to December 31, 2004. The progress, technical and other reports and publications are consolidated by the contracting year and also by the cooperative agreement tasks. The listing sorted by tasks is also sub-sorted by fiscal year for easier navigation. These listings are given in appendix A and Appendix B of this summary report. Individual report files are located in each fiscal year directory (i.e., FY00, FY01, etc. up to FY04). The complete listing and report files are also posted on the web site and is fully navigable by these two criteria. The web site is at: http://www.ceere.org/beep/beep{_}pubsanddownloads.html. More significant and less obvious part of deliverables are applications of this research, which are used in everyday operations of NFRC, software tools and manufacturers design practice, which has significantly changed as a result of this and related research efforts.
Date: September 15, 2006
Creator: Curcija, Dragan C.
Object Type: Report
System: The UNT Digital Library
Fuel Cell Applied Research Project (open access)

Fuel Cell Applied Research Project

Since November 12, 2003, Northern Alberta Institute of Technology has been operating a 200 kW phosphoric acid fuel cell to provide electrical and thermal energy to its campus. The project was made possible by funding from the U.S. Department of Energy as well as by a partnership with the provincial Alberta Energy Research Institute; a private-public partnership, Climate Change Central; the federal Ministry of Western Economic Development; and local natural gas supplier, ATCO Gas. Operation of the fuel cell has contributed to reducing NAIT's carbon dioxide emissions through its efficient use of natural gas.
Date: September 15, 2006
Creator: Richardson, Lee
Object Type: Report
System: The UNT Digital Library
Novel Smart Windows Based on Transparent Phosphorescent OLEDs (open access)

Novel Smart Windows Based on Transparent Phosphorescent OLEDs

In this program, Universal Display Corporation (UDC) and Princeton University developed the use of white transparent phosphorescent organic light emitting devices (PHOLEDs{trademark}) to make low-cost ''transparent OLED (TOLED) smart windows'', that switch rapidly from being a highly efficient solid-state light source to being a transparent window. PHOLEDs are ideal for large area devices, and the UDC-Princeton team has demonstrated white PHOLEDs with efficiencies of >24 lm/W at a luminance of 1,000 cd/m{sup 2}. TOLEDs have transparencies >70% over the visible wavelengths of light, but their transparency drops to less than 5% for wavelengths shorter than 350 nm, so they can also be used as ultraviolet (UV) light filters. In addition to controlling the flow of UV radiation, TOLEDs coupled with an electromechanical or electrically activated reflecting shutter on a glass window can be employed to control the flow of heat from infrared (IR) radiation by varying the reflectance/transparency of the glass for wavelengths greater than 800nm. One particularly attractive shutter technology is reversible electrochromic mirrors (REM). Our goal was therefore to integrate two innovative concepts to meet the U.S. Department of Energy goals: high power efficiency TOLEDs, plus electrically controlled reflectors to produce a ''smart window''. Our efforts during this …
Date: September 15, 2006
Creator: D'Andrade, Brian & Forest, Stephen
Object Type: Report
System: The UNT Digital Library
A Cone Jet-Finding Algorithm for Heavy Ion Collisions at LHC Energies (open access)

A Cone Jet-Finding Algorithm for Heavy Ion Collisions at LHC Energies

Standard jet finding techniques used in elementary particle collisions have not been successful in the high track density of heavy-ion collisions. This paper describes a modified cone-type jet finding algorithm developed for the complex environment of heavy-ion collisions. The primary modification to the algorithm is the evaluation and subtraction of the large background energy, arising from uncorrelated soft hadrons, in each collision. A detailed analysis of the background energy and its event-by-event fluctuations has been performed on simulated data, and a method developed to estimate the background energy inside the jet cone from the measured energy outside the cone on an event-by-event basis. The algorithm has been tested using Monte-Carlo simulations of Pb+Pb collisions at {radical}s = 5.5 TeV for the ALICE detector at the LHC. The algorithm can reconstruct jets with a transverse energy of 50 GeV and above with an energy resolution of {approx} 30%.
Date: September 15, 2006
Creator: Blyth, S; Horner, M J; Awes, T; Cormier, T; Gray, H; Klay, J L et al.
Object Type: Article
System: The UNT Digital Library
Control Rod Studies for Enigma Configurations. (open access)

Control Rod Studies for Enigma Configurations.

None
Date: September 15, 2006
Creator: Aliberti, G.; Taiwo, T. A.; Palmiotti, G.; Tommasi, J. & Jacqmin,R.
Object Type: Report
System: The UNT Digital Library
Neutronic assessment of stringer fuel assembly design for liquid-salt-cooledvery high temperature reactor (LS-VHTR). (open access)

Neutronic assessment of stringer fuel assembly design for liquid-salt-cooledvery high temperature reactor (LS-VHTR).

Neutronic studies of 18-pin and 36-pin stringer fuel assemblies have been performed to ascertain that core design requirements for the Liquid-Salt Cooled Very High Temperature Reactor (LS-VHTR) can be met. Parametric studies were performed to determine core characteristics required to achieve a target core cycle length of 18 months and fuel discharge burnup greater than 100 GWd/t under the constraint that the uranium enrichment be less than 20% in order to support non-proliferation goals. The studies were done using the WIMS9 lattice code and the linear reactivity model to estimate the core reactivity balance, fuel composition, and discharge burnup. The results show that the design goals can be met using a 1-batch fuel management scheme, uranium enrichment of 15% and a fuel packing fraction of 30% or greater for the 36-pin stringer fuel assembly design.
Date: September 15, 2006
Creator: Szakaly, F. J.; Kim, T. K. & Taiwo, T. A.
Object Type: Report
System: The UNT Digital Library
First Operation of a Free-Electron Laser Generating GW Power Radiation at 32-Nm Wavelength (open access)

First Operation of a Free-Electron Laser Generating GW Power Radiation at 32-Nm Wavelength

Many scientific disciplines ranging from physics, chemistry and biology to material sciences, geophysics and medical diagnostics need a powerful X-ray source with pulse lengths in the femtosecond range. This would allow, for example, time-resolved observation of chemical reactions with atomic resolution. Such radiation of extreme intensity, and tunable over a wide range of wavelengths, can be accomplished using high-gain free-electron lasers (FEL). Here we present results of the first successful operation of an FEL at a wavelength of 32 nm, with ultra-short pulses (25 fs FWHM), a peak power at the Gigawatt level, and a high degree of transverse and longitudinal coherence. The experimental data are in full agreement with theory. This is the shortest wavelength achieved with an FEL to date and an important milestone towards a user facility designed for wavelengths down to 6 nm. With a peak brilliance exceeding the state-of-the-art of synchrotron radiation sources by seven orders of magnitude, this device opens a new field of experiments, and it paves the way towards sources with even shorter wavelengths, such as the Linac Coherent Light Source at Stanford, USA, and the European X-ray Free Electron Laser Facility in Hamburg, Germany.
Date: September 15, 2006
Creator: Ayvazian, V.; Baboi, N.; Bahr, J.; Balandin, V.; Beutner, B.; Brandt, A. et al.
Object Type: Article
System: The UNT Digital Library