States

Physics modeling of tandem mirror devices with high-field test cell inserts (open access)

Physics modeling of tandem mirror devices with high-field test cell inserts

Recently developed plasma physics models of tandem mirror operation with a high-field technology test cell insert in the central cell are described in detail. These models have been incorporated in the TMRBAR tandem mirror reactor physics code. Results of a benchmark case for the code models against previous analysis of the MFTF - ..cap alpha.. /sup +/ T configuration are given. A brief users guide to the new TMRBAR with the test cell models is also presented. Some description of the applications of the models to MFTF - ..cap alpha.. /sup +/ T and FPD - II + T configurations is made. References are given to separate reports on these studies.
Date: April 15, 1985
Creator: Fenstermacher, M. E. & Campbell, R. B.
Object Type: Report
System: The UNT Digital Library
Improved Approach to Characterizing and Presenting Streak Camera Performance (open access)

Improved Approach to Characterizing and Presenting Streak Camera Performance

The performance of a streak camera recording system is strongly linked to the technique used to amplify, detect and quantify the streaked image. At the Lawrence Livermore National Laboratory (LLNL) streak camera images have been recorded both on film and by fiber-optically coupling to charge-coupled devices (CCD's). During the development of a new process for recording these images (lens coupling the image onto a cooled CCD) the definitions of important performance characteristics such as resolution and dynamic range were re-examined. As a result of this development, these performance characteristics are now presented to the streak camera user in a more useful format than in the past. This paper describes how these techniques are used within the Laser Fusion Program at LLNL. The system resolution is presented as a modulation transfer function, including the seldom reported effects that flare and light scattering have at low spatial frequencies. Data are presented such that a user can adjust image intensifier gain and pixel averaging to optimize the useful dynamic range in any particular application.
Date: July 15, 1985
Creator: Wiedwald, J. D. & Jones, B. A.
Object Type: Article
System: The UNT Digital Library
Status report on the Los Alamos National Laboratory Ion Beam Facility (open access)

Status report on the Los Alamos National Laboratory Ion Beam Facility

The Ion Beam Facility operated for 6000 machine hours last year, ranging in energy from 300 Kev to 24 Mev. Improvements include cryopumps replacing diffusion pumps, a rebuilding of the tandem chopper electronics and the vertical's corona charging system. Methane molecules were successfully accelerated by the vertical in quantities of hundreds of nanoamperes. Two replacement magnet power supplies on the tandem and a completely new capacitor shell regulator on the vertical are soon to be installed.
Date: November 15, 1985
Creator: Woods, R.; Tesmer, J.; Rowton, L.; Ingalls, W.; Chaparro, G.; Goosney, G. et al.
Object Type: Article
System: The UNT Digital Library
Fabrication of Separator Demonstration Facility process vessel (open access)

Fabrication of Separator Demonstration Facility process vessel

The process vessel system is the central element in the Separator Development Facility (SDF). It houses the two major process components, i.e., the laser-beam folding optics and the separators pods. This major subsystem is the critical-path procurement for the SDF project. Details of the vaious parts of the process vessel are given.
Date: January 15, 1985
Creator: Oberst, E.F.
Object Type: Report
System: The UNT Digital Library
Magnetic shielding for the long-pulse, pure-beam source neutralizers on the MFTF-B (open access)

Magnetic shielding for the long-pulse, pure-beam source neutralizers on the MFTF-B

Present ion sources produce deuterium ions plus small amounts of impurity ions including oxygen. The oxygen current is readily trapped by the Mirror Fusion Test Facility-B (MFTF-B) plasma and represents a severe energy loss mechanism. A pure-beam source-neutralizer has been designed by LLNL for the MFTF-B. This concept uses momentum separation by closely coupling an electromagnet to the source to purify the beam. This design requires a low pressure in the neutralizer, implying a long length and a large diameter for high conductance. Present designs require a 55-in. diameter by 60-in. long magnetically shielded region. This shield encloses the source and the separator magnet, and acts as the neutralizer duct for the beam. The fringe fields from the MFTF-B magnets penetrate the pure-beam neutralizer along the beamline axis. Field strengths on the order of three hundred gauss must be reduced to less than 6 gauss axial and 0.2 gauss transverse to the beam. Conventional single and double layer shielding designs require excessive amounts of permeable material. Multiple layer shields using a soft iron outer shield with a highly permeable inner shield require a 4 3/4-in.-thick outer shield. We have rejected this as a possible shielding solution. Active shielding, using two …
Date: November 15, 1985
Creator: Kerns, J.; Stone, R.; Fabyan, F. & Martin, D.
Object Type: Article
System: The UNT Digital Library
Application of structural-mechanics methods to the design of large tandem-mirror fusion devices (MFTF-B). Revision 1 (open access)

Application of structural-mechanics methods to the design of large tandem-mirror fusion devices (MFTF-B). Revision 1

The Mirror Fusion Test Facility (MFTF-B) at Lawrence Livermore National Laboratory requires state-of-the-art structural-mechanics methods to deal with access constraints for plasma heating and diagnostics, alignment requirements, and load complexity and variety. Large interactive structures required an integrated analytical approach to achieve a reasonable level of overall system optimization. The Tandem Magnet Generator (TMG) creates a magnet configuration for the EFFI calculation of electromagnetic-field forces that, coupled with other loads, form the input loading to magnet and vessel finite-element models. The analytical results provide the data base for detailed design of magnet, vessel, foundation, and interaction effects. 13 refs.
Date: August 15, 1985
Creator: Karpenko, V.N. & Ng, D.S.
Object Type: Article
System: The UNT Digital Library
Investigation of component failures in downhole geothermal pumping systems. Final report (open access)

Investigation of component failures in downhole geothermal pumping systems. Final report

This study investigated component failures in electric, downhole submersible pumps which prevented the attainment of one year continuous downhole running times in geothermal wells at temperatures up to 375/sup 0/F. The feasibility of a pressurized motor to prevent brine intrusion was investigated, as well as improved pothead and packoff designs, and brine scale buildup on impeller sleeve bearings and thrust washers. (ACR)
Date: March 15, 1985
Creator: Werner, Douglas K.
Object Type: Report
System: The UNT Digital Library
Malignant melanoma at a scientific laboratory (open access)

Malignant melanoma at a scientific laboratory

The general consensus of the seven reviewers is that occupational exposures at Lawrence Livermore National Laboratory have not been established as a causal factor for the observed excess of malignant melanoma. Several observations support the impression that some or all of the observed melanoma excess may be attributable to intense surveillance and enhanced detection of early stage melanoma lesions. Since the incidence of melanomas among Laboratory employees has not diminished, an early harvesting effect is unlikely. This suggests the distinct possibility that localized, in situ melanomas that would normally not be detected are being reported, and that in the absence of this enhanced detection, many of these early stage lesions would show little or no clinical progression. This phenomenon would explain the continued high incidence of melanomas in the absence of a physical or chemical inciting cause. A key point in this reasoning is the issue of the rate of growth of early stage melanomas, and this point remains a key question for study. Even if the observed excess cannot be explained by detection bias, the reviewers agree that the Austin and Reynolds' study does not make a convincing case for occupational factors being a cause of the high melanoma …
Date: November 15, 1985
Creator: Shy, C.M.; Checkoway, H. & Marshall, E.G.
Object Type: Report
System: The UNT Digital Library
Scoping studies of vapor behavior during a severe accident in a metal-fueled reactor (open access)

Scoping studies of vapor behavior during a severe accident in a metal-fueled reactor

Scoping calculations have been performed examining the consequences of fuel melting and pin failures for a reactivity-insertion type accident in a sodium-cooled, pool-type reactor fueled with a metal alloy fuel. The principal gas and vapor species released are shown to be Xe, Cs,and bond sodium contained within the fuel porosity. Fuel vapor pressure is insignificant, and there is no energetic fuel-coolant interaction for the conditions considered. Condensation of sodium vapor as it expands into the upper sodium pool in a jet mixing regime may occur as rapidly as the vapor emerges from the disrupted core (although reactor-material experiments are needed to confirm these high condensation rates). If the predictions of rapid direct-contact condensation can be verified experimentally for the sodium system, the implication is that the ability of vapor expansion to perform appreciable work on the system is largely eliminated. Furthermore, the ability of an expanding vapor bubble to transport fuel and fission product species to the cover gas region where they may be released to the containment is also largely eliminated. The radionuclide species except for fission gas are largely retained within the core and sodium pool.
Date: April 15, 1985
Creator: Spencer, B.W. & Marchaterre, J.F.
Object Type: Article
System: The UNT Digital Library
Economic requirements for competitive laser fusion power production (open access)

Economic requirements for competitive laser fusion power production

An economic model of a laser fusion commercial power plant is used to identify the design and operating regimes of the driver, target and reaction chamber that will result in economic competitiveness with future fission and coal plants. We find that, for a plant with a net power of 1 GW/sub e/, the cost of the driver must be less than $0.4 to 0.6 B, and the recirculating power fraction must be less than 25%. Target gain improvements at low driver energy are the most beneficial but also the most difficult to achieve. The optimal driver energy decreases with increasing target technology. The sensitivity of the cost of electricity to variations in cost and performance parameters decreases with increasing target technology. If chamber pulse rates of a few Hz can be achieved, then gains of 80 to 100 will be sufficient, and higher pulse rates do not help much. Economic competitiveness becomes more difficult with decreasing plant size. Finally, decreasing the cost of the balance of plant has the greatest beneficial effect on economic competitiveness. 6 refs., 5 figs., 2 tabs.
Date: November 15, 1985
Creator: Hogan, W. J. & Meier, W. R.
Object Type: Article
System: The UNT Digital Library
Concept for the intrinsic dielectric strength of electrical insulation materials (open access)

Concept for the intrinsic dielectric strength of electrical insulation materials

A concept is described for a possible definition of the intrinsic dielectric strength of insulating materials, which can be considered as a fundamental material property similar to other material properties, such as Young's modulus, index of refraction, and expansion coefficients. The events leading to the recognition of this property are reported, and the property is defined. This intrinsic dielectric strength concept should facilitate interpretation of results from accelerated and/or natural aging programs intended to predict electrical insulation service life of encapsulants in photovoltaic modules. As a practical application, this new concept enabled a possible explanation of the cause of failures in buried high-voltage cables with polyethylene insulation, and a possible explanation of the causes of electrical trees in polyethylene; these also are described.
Date: April 15, 1985
Creator: Cuddihy, E. F.
Object Type: Report
System: The UNT Digital Library
1 to 2 GeV/c beam line for hypernuclear and kaon research (open access)

1 to 2 GeV/c beam line for hypernuclear and kaon research

A kaon beam line operating in the range from 1.0 to 2.0 GeV/c is proposed. The line is meant for kaon and pion research in a region hitherto inaccessible to experimenters. Topics in hypernuclear and kaon physics of high current interest include the investigation of doubly strange nuclear systems with the K/sup -/,K/sup +/ reaction, searching for dibaryon resonances, hyperon-nucleon interactions, hypernuclear ..gamma.. rays, and associated production of excited hypernuclei. The beam line would provide separated beams of momentum analyzed kaons at intensities greater than 10/sup 6/ particles per spill with a momentum determined to one part in a thousand. This intensity is an order of magnitude greater than that currently available. 63 references.
Date: February 15, 1985
Creator: Chrien, R. E.
Object Type: Report
System: The UNT Digital Library
Theoretical aspects of magnetic helicity (open access)

Theoretical aspects of magnetic helicity

None
Date: April 15, 1985
Creator: Hammer, J. H.
Object Type: Article
System: The UNT Digital Library
Integrating quality assurance and research and development (open access)

Integrating quality assurance and research and development

Quality assurance programs cannot be transferred from one organization to another without attention to existing cultures and traditions. Introduction of quality assurance programs constitutes a significant change and represents a significant impact on the organizational structure and operational mode. Quality assurance professionals are change agents, but do not know how to be effective ones. Quality assurance as a body of knowledge and experience can only become accepted when its practitioners become familiar with their role as change agents. 8 references.
Date: February 15, 1985
Creator: Dronkers, J.J.
Object Type: Article
System: The UNT Digital Library
Interim Storage Facility decommissioning. Final report (open access)

Interim Storage Facility decommissioning. Final report

Decontamination and decommissioning of the Interim Storage Facility were completed. Activities included performing a detailed radiation survey of the facility, removing surface and imbedded contamination, excavating and removing the fuel storage cells, restoring the site to natural conditions, and shipping waste to Hanford, Washington, for burial. The project was accomplished on schedule and 30% under budget with no measurable exposure to decommissioning personnel.
Date: March 15, 1985
Creator: Johnson, R. P. & Speed, D. L.
Object Type: Report
System: The UNT Digital Library
Progress in inertial fusion at LLNL (open access)

Progress in inertial fusion at LLNL

Experiments at LLNL using the 10 TW Novette laser have led to significantly increased understanding of laser/plasma coupling. Tests using 1.06 ..mu..m, 0.53 ..mu..m and 0.26 ..mu..m light have shown increased light absorption, increased efficiency of conversion to x-rays, and decreased production of suprathermal electrons as the wavelength of the incident light decreases. The data indicate that stimulated Raman scattering is the source of the excessive hot electrons and that the effect can be controlled by the proper selection of laser frequency and target material. The control of these effects has led to achievement of higher inertial fusion target compressions and to production of the first laboratory x-ray laser.
Date: April 15, 1985
Creator: Storm, E.
Object Type: Article
System: The UNT Digital Library
Flow characteristics of the Cascade granular blanket (open access)

Flow characteristics of the Cascade granular blanket

Analysis of a single granule on a rotating cone shows that for the 35/sup 0/ half-angle, double-cone-shaped Cascade chamber, blanket granules will stay against the chamber wall if the rotational speed is 50 rpm or greater. The granules move axially down the wall with a slight (5-mm or less) sinusoidal oscillation in the circumferential direction. Granule chute-flow experiments confirm that two-layered flow can be obtained when the chute is inclined slightly above the granular material angle of repose. The top surface layer is thin and fast moving (supercritical flow). A thick bottom layer moves more slowly (subcritical flow controlled at the exit) with a velocity that increases with distance from the bottom of the chute. This is a desirable velocity profile because in the Cascade chamber about one-third of the fusion energy is deposited in the form of x rays and fusion-fuel-pellet debris in the top surface (inner-radius) layer.
Date: April 15, 1985
Creator: Pitts, J.H. & Walton, O.R.
Object Type: Article
System: The UNT Digital Library
Shape memory alloy seals for geothermal applications (open access)

Shape memory alloy seals for geothermal applications

A shape memory radial seal was fabricated with a ''U'' cross section. Upon heating the seal recovered its original ''V'' shape and produced a high pressure seal. The sealing pressure which can be developed is approximately 41 MPa (60,000 psi), well in excess of the pressure which can be produced in conventional elastomeric seals. The low modulus martensite can conform readily to the sealing surface, and upon recovery produce a seal capable of high pressure fluid or gas confinement. The corrosion resistance of nickel-titanium in a broad range of aggressive fluids has been well established and, as such, there is little doubt that, had time permitted, a geothermal pump of flange fluid tried would have been successful.
Date: September 15, 1985
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Recondensation of vaporized material in the Cascade ICF reactor (open access)

Recondensation of vaporized material in the Cascade ICF reactor

In the Cascade inertial fusion reactor, the innermost blanket zone consists of solid granules of C or BeO. The x rays from a fusion pulse of 300 MJ will vaporize up to 1 kg of material. The temperature of this vaporized material may reach 1 to 2 electron volts. The CONRAD code was used to calculate the energy and mass exchange between this hot plasma and the cold wall until complete recondensation of the material reduces the chamber particle density to 3 x 10 V cm T, which is required for propagation of the next laser pulse. Our calculations indicate that recondensation times are in the few to tens of milliseconds range even if only the first layer of granules is available for recondensation. Gas flow calculations indicate that several layers of granules should be available for recondensation. We discuss phenomenology, not currently in the CONRAD model, that could lead to increased recondensation times. 17 refs., 5 figs.
Date: November 15, 1985
Creator: Hogan, William J. & Peterson, Robert R.
Object Type: Article
System: The UNT Digital Library
Technical considerations for flexible piping design in nuclear power plants (open access)

Technical considerations for flexible piping design in nuclear power plants

The overall objective of this research project is to develop a technical basis for flexible piping designs which will improve piping reliability and minimize the use of pipe supports, snubbers, and pipe whip restraints. The current study was conducted to establish the necessary groundwork based on the piping reliability analysis. A confirmatory piping reliability assessment indicated that removing rigid supports and snubbers tends to either improve or affect very little the piping reliability. A couple of changes to be implemented in Regulatory Guide (RG) 1.61 and RG 1.122 aimed at more flexible piping design were investigated. It was concluded that these changes substantially reduce calculated piping responses and allows piping redesigns with significant reduction in number of supports and snubbers without violating ASME code requirements.
Date: March 15, 1985
Creator: Lu, S.C. & Chou, C.K.
Object Type: Article
System: The UNT Digital Library
Development of the cascade inertial-confinement-fusion reactor (open access)

Development of the cascade inertial-confinement-fusion reactor

Cascade, originally conceived as a football-shaped, steel-walled reactor containing a Li/sub 2/O granule blanket, is now envisaged as a double-cone-shaped reactor containing a two-layered (three-zone) flowing blanket of BeO and LiAlO/sub 2/ granules. Average blanket exit temperature is 1670/sup 0/K and gross plant efficiency (net thermal conversion efficiency) using a Brayton cycle is 55%. The reactor has a low-activation SiC-tiled wall. It rotates at 50 rpm, and the granules are transported to the top of the heat exchanger using their peripheral speed; no conveyors or lifts are required. The granules return to the reactor by gravity. After considerable analysis and experimentation, we continue to regard Cascade as a promising reactor concept with the advantages of safety, efficiency, and low activation.
Date: April 15, 1985
Creator: Pitts, J.H.
Object Type: Article
System: The UNT Digital Library
Numerical determination of injector design for high beam quality (open access)

Numerical determination of injector design for high beam quality

The performance of a free electron laser strongly depends on the electron beam quality or brightness. The electron beam is transported into the free electron laser after it has been accelerated to the desired energy. Typically the maximum beam brightness produced by an accelerator is constrained by the beam brightness deliverd by the accelerator injector. Thus it is important to design the accelerator injector to yield the required electron beam brightness. The DPC (Darwin Particle Code) computer code has been written to numerically model accelerator injectors. DPC solves for the transport of a beam from emission through acceleration up to the full energy of the injector. The relativistic force equation is solved to determine particle orbits. Field equations are solved for self consistent electric and magnetic fields in the Darwin approximation. DPC has been used to investigate the beam quality consequences of A-K gap, accelerating stress, electrode configuration and axial magnetic field profile.
Date: October 15, 1985
Creator: Boyd, J.K.
Object Type: Article
System: The UNT Digital Library
Optimum ranges for x-ray thickness measurements (open access)

Optimum ranges for x-ray thickness measurements

Film thicknesses can be measured by two x-ray methods: x-ray absorption (gauging or radiography) and x-ray fluorescence. Optimization of both methods is discussed.
Date: October 15, 1985
Creator: Ryon, R.W.
Object Type: Article
System: The UNT Digital Library
Analysis of plutonium gamma-ray spectra by small portable computers (open access)

Analysis of plutonium gamma-ray spectra by small portable computers

A sophisticated program for isotopic analysis of plutonium gamma-ray spectra using small computers has been developed. It is implemented on a DEC LSI-11/2 configured in a portable unit without a mass storage device for use by IAEA inspectors in the field. Only the positions of the 148-keV /sup 241/Pu and 208-keV /sup 237/U peaks are needed as input. Analysis is completed in 90 seconds by fitting isotopic component response functions to peak multiplets. 9 refs., 2 figs., 1 tab.
Date: May 15, 1985
Creator: Ruhter, W.; Gunnink, R.; Camp, D. & DeCarolis, M.
Object Type: Article
System: The UNT Digital Library