NIF Power Conditioning System Testing at LLNL (open access)

NIF Power Conditioning System Testing at LLNL

The National Ignition Facility (NIF) is now under construction at the Lawrence Livermore National Laboratory (LLNL). The Power Conditioning System (PCS) for NIF, when completed will consist of a 192 nearly identical 2 megajoule capacitor storage banks driving 7680 two meter long flashlamps. A fully integrated single-module test facility was completed in August of 2000 at LLNL. The purpose to the Test Facility is to conduct Reliability and Maintainability (RAM) testing of a true ''First Article'' system (built to the final drawing package as opposed to a prototype). The test facility can be fired once every ten minutes with a total peak output current of 580kA with a pulse width of 400us. To date over 4000 full power shots have been conducted at this facility.
Date: June 5, 2001
Creator: Fulkerson, E S; Newton, M; Hulsey, s; Hammon, J & Moore, W
Object Type: Article
System: The UNT Digital Library
Automated Test System for NIF Flashlamps (open access)

Automated Test System for NIF Flashlamps

This paper describes design and operation of the flashlamp test system, used to evaluate the primary laser flashlamps on the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) in Livermore, California. The tester delivers repetitive high voltage pulses to a series pair of flashlamps at levels closely simulating those encountered in normal operation. Each lamp pair is subjected to a pre-ionization and main pulse shot sequence, with two minute intervals between shots. This capability allows the manufacturer to test and evaluate the flashlamps for infant mortality and longevity before delivery to NIF. All operations are under computer control with fully automated test and data acquisition capabilities requiring minimal operator input. The system is designed to operate continuously. Typical pre-ionization and main pulse outputs are: (1) Pre-ionization Pulse--V{sub chg} = 27kV, I{sub peak} = 3kA, E = 2.4kJ; Pulse Width--(10%-90%) - 200us; Main Pulse--V{sub chg} = 23kV, I{sub peak} - 24kA, E - 78.6kJ; and Pulse Width--(10%-90%) - 350us.
Date: June 5, 2001
Creator: da Silva, T; Creely, P; Hammon, J; Shaw, R; Boyle, R T & Fulkerson, E S
Object Type: Article
System: The UNT Digital Library
Secondary Uranium-Phase Paragenesis and Incorporation of Radionuclides into Secondary Phase (open access)

Secondary Uranium-Phase Paragenesis and Incorporation of Radionuclides into Secondary Phase

The purpose of this analysis/model report (AMR) is to assess the potential for uranium (U) (VI) compounds, formed during the oxidative corrosion of spent uranium-oxide (UO{sub 2}) fuels, to sequester certain radionuclides and, thereby, limit their release. The ''unsaturated drip tests'' being conducted at Argonne National Laboratory (ANL) provide the basis of this AMR (Table 1). The ANL drip tests on spent fuel are the only experiments on fuel corrosion from which solids have been analyzed for trace levels of radionuclides. Brief summaries are provided of the results from other selected corrosion and dissolution experiments on spent UO{sub 2} fuels, specifically those conducted under nominally oxidizing conditions. Discussions of the current understanding of thermodynamic and kinetic properties of U(VI) compounds is provided in order to outline the scientific basis for modeling precipitation and dissolution of potential radionuclide-bearing phases under repository-relevant conditions. Attachment I provides additional information on corrosion mechanisms and behaviors of radionuclides in the tests at ANL. Attachment II reviews occurrence, formation, and alteration (collectively known as paragenesis) of naturally occurring U(VI) minerals because natural mineral occurrences can be used to assess the possible long-term behaviors of U(VI) compounds formed in short-term laboratory experiments and to extrapolate experimental results …
Date: June 5, 2001
Creator: Finch, R.
Object Type: Report
System: The UNT Digital Library
10 (micro)m and 5 (micro)m Pinhole-Assisted Point-Projection Backlit Imaging for NIF (open access)

10 (micro)m and 5 (micro)m Pinhole-Assisted Point-Projection Backlit Imaging for NIF

Pinhole-assisted point-projection backlighting with 10{micro}m and 5 {micro}m pinholes placed a small distance of order 1 mm away from the backlighter produces images with large field of view and high resolution. Pinholes placed closely to high-power backlighter sources can vaporize and close due to x-ray driven ablation, thereby limiting the usefulness of this method. A study of streaked 1-D backlit imaging of 25 {micro}m W wires using the OMEGA laser is presented. The pinhole closure timescale for 10 {micro}m pinholes placed 0.45 mm and 1 mm distant from the backlighter is 1.3 ns and 2.2 ns, respectively. Similar timescales for 5 {micro}m pinholes is also presented. Successful wire imaging prior to pinhole closure is clearly demonstrated.
Date: June 5, 2001
Creator: Bullock, A. B.; Landen, O. L. & Bradley, D. K.
Object Type: Article
System: The UNT Digital Library
An overview of the Argonne National Laboratory fast critical experiments 1963-1990. (open access)

An overview of the Argonne National Laboratory fast critical experiments 1963-1990.

None
Date: June 5, 2001
Creator: LeSage, L.G.
Object Type: Report
System: The UNT Digital Library
Strange Goings on in Quark Matter. (open access)

Strange Goings on in Quark Matter.

We review recent work on how the superfluid state of three flavor quark matter is affected by non-zero quark masses and chemical potentials. The study of hadronic matter at high baryon density has recently attracted a lot of interest. At zero baryon density chiral symmetry is broken by a quark-anti-quark condensate. At high density condensation in the quark-anti-quark channel is suppressed. Instead, attractive interactions in the color anti-symmetric quark-quark channel favor the formation of diquark condensates. As a consequence, cold dense quark matter is expected to be a color superconductor. The symmetry breaking pattern depends on the density, the number of quark flavors, and their masses. A particularly symmetric phase is the color-flavor-locked (CFL) phase of three flavor quark matter. This phase is believed to be the true ground state of ordinary matter at very large density.
Date: June 5, 2001
Creator: Schafer, T.
Object Type: Article
System: The UNT Digital Library
Manganin Gauge and Reactive Flow Modeling Study of the Shock Initiation of PBX 9501 (open access)

Manganin Gauge and Reactive Flow Modeling Study of the Shock Initiation of PBX 9501

A series of 101mm diameter gas gun experiments was fired using manganin pressure gauges embedded in the HMX-based explosive PBX 9501 at initial temperatures of 20 C and 50 C. Flyer plate impact velocities were chosen to produce impact pressure levels in PBX 9501 at which the growth of explosive reaction preceding detonation was measured on most of the gauges and detonation pressure profiles were recorded on some of the gauges placed deepest into the explosive targets. All measured pressure histories for initial temperatures of 25 C and 50 C were essentially identical. Measured run distances to detonation at several input shock pressures agreed with previous results. An existing ignition and growth reactive flow computer model for shock initiation and detonation of PBX 9501, which was developed based on LANL embedded particle velocity gauge data, was tested on these pressure gauge results. The agreement was excellent, indicating that the embedded pressure and particle velocity gauge techniques yielded consistent results.
Date: June 5, 2001
Creator: Tarver, C M; Forbes, J W; Garcia, F & Urtiew, P A
Object Type: Article
System: The UNT Digital Library
Automatic Extraction of Closed Pixel Clusters for Target Cueing in Hyperspectral Images (open access)

Automatic Extraction of Closed Pixel Clusters for Target Cueing in Hyperspectral Images

Traditional algorithms for automatic target cueing (ATC) in hyperspectral images, such as the RX algorithm, treat anomaly detection as a simple hypothesis testing problem. Each decision threshold gives rise to a different set of anomalous pixels. The clustered Rx algorithm generates target cues by grouping anomalous pixels into spatial clusters, and retaining only those clusters that satisfy target specific spatial constraints. It produces one set of target cues for each of several decision thresholds, and conservatively requires {Omicron}(K{sup 2}) operations per pixel, where K is the number of spectral bands (which varies from hundreds to thousands in hyperspectral images). A novel ATC algorithm, known as ''Pixel Cluster Cueing'' (PCC), is discussed. PCC groups pixels into clusters based on spectral similarity and spatial proximity, and then selects only those clusters that satisfy target-specific spatial constraints as target cues. PCC requires only {Omicron}(K) operations per pixel, and it produces only one set of target cues because it is not an anomaly detection algorithm, i.e., it does not use a decision threshold to classify individual pixels as anomalies. PCC is compared both computationally and statistically to the RX algorithm.
Date: June 5, 2001
Creator: Paglieroni, D W & Perkins, D E
Object Type: Article
System: The UNT Digital Library
The Specification of Source-to-source Transformations for the Compile-time Optimization of Parallel Object-oriented Scientific Applications (open access)

The Specification of Source-to-source Transformations for the Compile-time Optimization of Parallel Object-oriented Scientific Applications

The performance of object-oriented applications in scientific computing often suffers from the inefficient use of high-level abstractions provided by underlying libraries. Since these library abstractions are not part of the programming language itself there is no compiler mechanism to respect their semantics and thus to perform appropriate optimizations, e.g., array semantics within object-oriented array class libraries which permit parallel optimizations inconceivable to the serial compiler. We have presented the ROSE infrastructure as a tool for automatically generating library-specific preprocessors. These preprocessors can perform sematics-based source-to-source transformations of the application in order to introduce high-level code optimizations. In this paper we outline the design of ROSE and focus on the discussion of various approaches for specifying and processing complex source code transformations. These techniques are supposed to be as easy and intuitive as possible for the ROSE users, i.e. for the designers of the library-specific preprocessors.
Date: June 5, 2001
Creator: Quinlan, D & Kowarschik, M
Object Type: Article
System: The UNT Digital Library
Modeling The Effect of Drifts on the Edge, Scrape-Off Layer, and Divertor Plasma in DIII-D (open access)

Modeling The Effect of Drifts on the Edge, Scrape-Off Layer, and Divertor Plasma in DIII-D

Simulations of plasmas with a DIII-D shape indicate plasma drifts are important at power levels near the L- to H-mode plasma transition. In addition to enhancing plasma flows in the divertor region, drifts are found to play a key role in establishing highly sheared radial electric fields in the edge of the confined plasma, for the physics of the high confinement operating mode (H-mode). Measurements of the plasma structure in the vicinity of the X-point of DIII-D indicate the importance of drifts on plasma flow between the scrape-off layer (SOL) and closed field lines. The large electric fields provide large flows around the X-point, and these are conjectured to play a role in the transition from L- to H-mode confinement. These results indicate the relevance of modeling the edge and SOL plasmas of present tokamak devices using models which include E x B, {del}B, and pressure gradient drifts. The results of simulation of specific DIII-D discharges is reported in this paper. They start with discussion of the simulation of an Ohmic discharge in Section 2, including a study of the effect of varying several operational parameters. Simulation of a higher triangularity L-mode discharge is discussed in Section, and a summary …
Date: June 5, 2001
Creator: Porter, G. D.; Boedo, J. A.; Groebner, R. J.; Carlstrom, T. N.; Rognlien, T. D.; Rensink, M. E. et al.
Object Type: Article
System: The UNT Digital Library
Shock Initiation of UF-TATB at 250(degree)C (open access)

Shock Initiation of UF-TATB at 250(degree)C

The shock initiation properties of pure ultrafine grade triaminotrinitrobenzne (UF-TATB) pressed to an initial density of 1.80 g/cm{sup 3} and fired at ambient temperature and 250 C are reported. Embedded manganin pressure gauges are used to measure the pressure histories during the buildup to detonation at several input pressures. The ambient temperature results confirm previous run distance to detonation versus shock pressure results. UF-TATB at 250 C is shown to be much more shock sensitive than it is at ambient temperature. At high impact pressures, the shock sensitivity of UF-TATB at 250 C approaches that of HMX-based explosives under ambient conditions. Ignition and Growth reactive flow models are developed for UF-TATB at both temperatures to allow predictions to be made for other scenarios.
Date: June 5, 2001
Creator: Urtiew, P A; Forbes, J W; Garcia, F & Tarver, C M
Object Type: Article
System: The UNT Digital Library
A New Technique for Troubleshooting Large Capacitive Energy Storage Banks (open access)

A New Technique for Troubleshooting Large Capacitive Energy Storage Banks

The Power Conditioning System (PCS) of the National Ignition Facility (NIF) like many pulse power systems relies on large numbers of inductively isolated high voltage capacitors configured in parallel for energy storage. When an energy storage capacitor fails in such a capacitor bank, there is often little or no external indication showing which capacitor failed. Identifying the failed component can be a time consuming and potentially hazardous operation. Conventional methods using capacitance meters require that each capacitor be disconnected and tested independently. They have developed a new non-invasive technique (i.e. no dismantling of the bank is required) that greatly improves personnel safety as well reducing troubleshooting time.
Date: June 5, 2001
Creator: Fulkerson, S E & Hammon, J
Object Type: Article
System: The UNT Digital Library
Standard Formats for Atomic Data: the APED (open access)

Standard Formats for Atomic Data: the APED

Standardized formats for atomic data used in calculating emission from a collisionally-ionized plasma are described. The formats use the astronomical-standard FITS format, and are extendible to other purposes, such as photoionization data. The formats emphasize storing references to the original data source and keeping the data in as-received form, to aid in checking against the original literature.
Date: June 5, 2001
Creator: Smith, R K; Brickhouse, N S; Liedahl, D A & Raymond, J C
Object Type: Article
System: The UNT Digital Library
Depleted uranium hexafluoride management program : data compilation for the Portsmouth site. (open access)

Depleted uranium hexafluoride management program : data compilation for the Portsmouth site.

This report is a compilation of data and analyses for the Portsmouth site, near Portsmouth, Ohio. The data were collected and the analyses were done in support of the U.S. Department of Energy (DOE) 1999 Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride (DOE/EIS-0269). The report describes the affected environment at the Portsmouth site and summarizes potential environmental impacts that could result from conducting the following depleted uranium hexafluoride (UF{sub 6}) management activities at the site: continued cylinder storage, preparation of cylinders for shipment, conversion, and long-term storage. DOE's preferred alternative is to begin converting the depleted UF{sub 6} inventory as soon as possible to either uranium oxide, uranium metal, or a combination of both, while allowing for use of as much of this inventory as possible.
Date: June 5, 2001
Creator: Hartmann, H. M.
Object Type: Report
System: The UNT Digital Library
Depleted uranium hexafluoride management program : data compilation for the K-25 site. (open access)

Depleted uranium hexafluoride management program : data compilation for the K-25 site.

This report is a compilation of data and analyses for the K-25 site on the Oak Ridge Reservation, Oak Ridge, Tennessee. The data were collected and the analyses were done in support of the U.S. Department of Energy (DOE) 1999 Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride (DOE/EIS-0269). The report describes the affected environment at the K-25 site and summarizes the potential environmental impacts that could result from continued cylinder storage and preparation of cylinders for shipment at the site. It is probable that the cylinders at the K-25 site will be shipped to another site for conversion. Because conversion and long-term storage of the entire inventory at the K-25 site are highly unlikely, these data are not presented in this report. DOE's preferred alternative is to begin converting the depleted uranium hexafluoride inventory as soon as possible to either uranium oxide, uranium metal, or a combination of both, while allowing for use of as much of this inventory as possible.
Date: June 5, 2001
Creator: Hartmann, H. M.
Object Type: Report
System: The UNT Digital Library
Plasma Profile and Shape Optimization for the Advanced Tokamak Power Plant, ARIES-AT (open access)

Plasma Profile and Shape Optimization for the Advanced Tokamak Power Plant, ARIES-AT

An advanced tokamak plasma configuration is developed based on equilibrium, ideal-MHD stability, bootstrap current analysis, vertical stability and control, and poloidal-field coil analysis. The plasma boundaries used in the analysis are forced to coincide with the 99% flux surface from the free-boundary equilibrium. Using an accurate bootstrap current model and external current-drive profiles from ray-tracing calculations in combination with optimized pressure profiles, beta(subscript N) values above 7.0 have been obtained. The minimum current drive requirement is found to lie at a lower beta(subscript N) of 5.4. The external kink mode is stabilized by a tungsten shell located at 0.33 times the minor radius and a feedback system. Plasma shape optimization has led to an elongation of 2.2 and triangularity of 0.9 at the separatrix. Vertical stability could be achieved by a combination of tungsten shells located at 0.33 times the minor radius and feedback control coils located behind the shield. The poloidal-field coils were optimized in location and current, providing a maximum coil current of 8.6 MA. These developments have led to a simultaneous reduction in the power plant major radius and toroidal field.
Date: June 5, 2001
Creator: Kessel, C. E.; Mau, T. K.; Jardin, S. C. & Najmabadi, F.
Object Type: Report
System: The UNT Digital Library
Security Implications of Typical Grid Computing Usage Scenarios (open access)

Security Implications of Typical Grid Computing Usage Scenarios

A Computational Grid is a collection of heterogeneous computers and resources spread across multiple administrative domains with the intent of providing users uniform access to these resources. There are many ways to access the resources of a Computational Grid, each with unique security requirements and implications for both the resource user and the resource provider. A comprehensive set of Grid usage scenarios are presented and analyzed with regard to security requirements such as authentication, authorization, integrity, and confidentiality. The main value of these scenarios and the associated security discussions are to provide a library of situations against which an application designer can match, thereby facilitating security-aware application use and development from the initial stages of the application design and invocation. A broader goal of these scenarios are to increase the awareness of security issues in Grid Computing.
Date: June 5, 2001
Creator: Humphrey, Marty & Thompson, Mary R.
Object Type: Article
System: The UNT Digital Library
Insulated Concrete Homes Increase Durability and Energy Efficiency (open access)

Insulated Concrete Homes Increase Durability and Energy Efficiency

New houses designed by Mercedes Homes in Melbourne, Florida, with technical support from the U.S. Department of Energy's Building America Program, save their homeowners money by using energy efficient features such as a high performance heat pump and solar control glazing to reduce cooling costs.
Date: June 5, 2001
Creator: America, Building; Hendron, B. & Poole, L.
Object Type: Book
System: The UNT Digital Library
PowerGuard Advanced Manufacturing, PVMaT Phase II Technical Progress Report; 1 July 1999--30 September 2000 (open access)

PowerGuard Advanced Manufacturing, PVMaT Phase II Technical Progress Report; 1 July 1999--30 September 2000

This project introduced incremental improvements to PowerGuard system components and manufacturing processes to significantly reduce the costs of a PowerGuard system. The improvement resulted in a lower cost, higher impact PV product. During Phase II, these accomplishments have resulted in: A production rate of greater than 400 PowerGuard tiles per shift (20 MW/year) manufacturing capacity; 57% cost reduction for PowerGuard tile; UL listing for four additional PowerGuard tiles configurations; Improved quality of finished goods due to improved tooling and processes in manufacturing, simultaneously improving throughput and lowering cost of $3.80Wp for large systems. In Phase III of this contract, PowerLight will continue efforts to improve the manufacturing processes for PowerGuard. Specific performance objectives during phase III are as follows: Demonstrate system cost reduction from $3.80/Wp to $3.05/Wp for large systems; Establish or assess the performance of dedicated PowerGuard PV module plant capacity of 2 MW per year; Complete wind tunnel testing of all design refinements; Produce an installation manual and training program for installing PowerGuard systems; Establish performance of manufacturing modifications based on assessment of commercial systems which incorporate the new features and processes; and Finalize UL, International Conference of Building Officials (ICBO), and international listings of PowerGuard improvements. These …
Date: June 5, 2001
Creator: Dinwoodie, T. L. & Botkin, J.
Object Type: Report
System: The UNT Digital Library