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Cause of pitting in beryllium (open access)

Cause of pitting in beryllium

Light microscopy, bare-film radiography, secondary ion mass spectroscopy, electron microprobe and physical testing were used to examine beryllium specimens exhibiting a stratified, pitted, pattern after chemical milling. The objective was to find the cause of this pattern. Specimens were found to have voids in excess of density specification allowances. These voids are attributed, at least in part, to the sublimation of beryllium fluoride during the vacuum hot pressing operation. The origin of the pattern is attributed to these voids and etching out of fines and associated impurities. Hot isostatic pressing with a subsequent heat treatment close residual porosity and dispersed impurities enough to correct the problem.
Date: April 16, 1982
Creator: Kershaw, R. P.
System: The UNT Digital Library
Bumps and poles in the S-matrix: A systematic study of 0 sup ++ and 2 sup ++ mesons plus a molecule approach to the E(1420) in the K K. pi. system (open access)

Bumps and poles in the S-matrix: A systematic study of 0 sup ++ and 2 sup ++ mesons plus a molecule approach to the E(1420) in the K K. pi. system

The goal of Hadron Spectroscopy is to find the spectrum of states formed by color singlet arrangements of quarks and gluons. Ideally these spectral states are associated with poles of the scattering matrix of hadrons which are the decay channels of the states. For example the {rho} meson is the lowest q{bar q} s-wave, spin one color singlet state and decays into {pi}{sup +}{pi}{sup -}. Since the {rho}decays in a relative p-wave, one finds the {rho} pole in the I = 1 p-wave {pi}{pi} phase shifts. There are forces between quarks and gluons which do not manifest themselves as true resonances and thus cannot be described by a Breit-Wigner pole. I will give some examples that are not Breit-Wigner poles of the scattering matrix but are important bumps in meson production. 22 refs., 10 figs.
Date: November 16, 1989
Creator: Longacre, R. S.
System: The UNT Digital Library
RODCON: a finite difference heat conduction computer code in cylindrical coordinates (open access)

RODCON: a finite difference heat conduction computer code in cylindrical coordinates

RODCON, a finite difference computer code, was developed to calculate the internal temperature distribution of the fuel rod simulator (FRS) for the Core Flow Test Loop (CFTL). RODCON solves the implicit, time-dependent forward-differencing heat transfer equation in 2-dimensional (Rtheta) cylindrical coordinates at an axial plane with user specified radial material zones and surface conditions at the FRS periphery. Symmetry of the boundary conditions of coolant bulk temperatures and film coefficients at the FRS periphery is not necessary.
Date: September 16, 1980
Creator: Conklin, J. C.
System: The UNT Digital Library
Probing the possibility of a /sup 12/C/sup 13/C abundance gradient from observations of interstellar CH/sup +/ (open access)

Probing the possibility of a /sup 12/C/sup 13/C abundance gradient from observations of interstellar CH/sup +/

I have performed high signal-to-noise (SN /equals/ 300 to 500) observations of interstellar CH/sup /plus// at Lick Observatory and at CTIO of the reddened, early-type stars HD 183143, HD 24432, and HD 157038 in an effort to probe the existence of a /sup 12/C/sup 13/C abundance gradient in our Galaxy.
Date: September 16, 1987
Creator: Hawkins, I.
System: The UNT Digital Library
Small Angle Physics at CDF: A Progress Report (open access)

Small Angle Physics at CDF: A Progress Report

In 1989 CDF collected data in special high beta runs with a trigger selecting elastic and inelastic events in order to measure the total cross section ({sigma}{sub tot}) and the differential elastic cross section (d{sigma}{sub el}/dt). Data were taken at cms energies of 300, 540, 1000 and 1800 GeV. A double arm magnetic spectrometer located along the beam pipe tags the particles scattered at very small angles and tracking detectors surrounding the interaction point reveal particles produced at larger angles. We discuss the status of the analysis of elastic and inelastic events with emphasis on the event selection and the background subtraction. 5 refs., 14 figs., 3 tabs.
Date: December 16, 1989
Creator: Paoletti, Riccardo
System: The UNT Digital Library
Comparative analysis of internal fuel motion in annular fuel designs (open access)

Comparative analysis of internal fuel motion in annular fuel designs

In this paper, the whole-core reactivity consequences of internal fuel motion in three annular fuel designs during a hypothetical 3 dollars/s transient overpower (TOP) accident are compared to determine the effect of geometric design variations. The PINEX-2 and PINEX-3 experiments were performed in the TREAT reactor using annular fuel pins irradiated in GETR. This paper investigates three combinations of solid and annular axial blankets and fission gas plena: top annular blanket and plenum, bottom annular blanket and plenum, and both top and bottom (dual) annular blankets and plena. The dual plena design case showed a significant decrease in internal fuel motion over the single plenum design cases.
Date: September 16, 1983
Creator: Smith, D. E.
System: The UNT Digital Library
New concept for a high-power beam dump (open access)

New concept for a high-power beam dump

A new concept for a dump for the ion and neutral beams used in the controlled nuclear fusion program uses thin sheets of a refractory metal such as tungsten formed into troughs having semi-circular cross sections. High-velocity water flowing circumferentially removes heat by subcooled nucleate boiling. Possible advantages are modular construction, lower water-pumping power, and a lower pressure drop than in conventional beam dumps. An example design calculation is shown for a dump capable of absorbing an incident flux of 10 kW/cm/sup 2/.
Date: April 16, 1980
Creator: Moir, R.W. & Taylor, C.E.
System: The UNT Digital Library
Magnetic shielding tests for MFTF-B neutral beamlines (open access)

Magnetic shielding tests for MFTF-B neutral beamlines

A test program to determine the effectiveness of various magnetic shielding designs for MFTF-B beamlines was established at Lawrence Livermore National Laboratory (LLNL). The proposed one-tenth-scale shielding-design models were tested in a uniform field produced by a Helmholtz coil pair. A similar technique was used for the MFTF source-injector assemblies, and the model test results were confirmed during the Technology Demonstration in 1982. The results of these tests on shielding designs for MFTF-B had an impact on the beamline design for MFTF-B. The iron-core magnet and finger assembly originally proposed were replaced by a simple, air-core, race-track-coil, bending magnet. Only the source injector needs to be magnetically shielded from the fields of approximately 400 gauss.
Date: November 16, 1983
Creator: Kerns, J.; Fabyan, J.; Wood, R. & Koger, P.
System: The UNT Digital Library
Richtmyer-Meshkov instabilities in stratified fluids (open access)

Richtmyer-Meshkov instabilities in stratified fluids

We present an analytic theory of Richtmyer-Meshkov instabilities in an arbitrary number N of stratified fluids subjected to a shock. Following our earlier work on Rayleigh-Taylor instabilities, the theory assumes incompressible flow in which a shock is treated an impulsive acceleration, g = ..delta.. v delta(tau/sub s), ..delta..v being the jump velocity induced in the system by a shock at time tau/sub s/. We discuss the special cases N = 2 and N = 3, and illustrate both Rayleigh-Taylor and Richtmyer-Meshkov instabilities by examples patterned after inertial confinement fusion implosions.
Date: December 16, 1983
Creator: Mikaelian, K.O.
System: The UNT Digital Library
Acceleration of compact torus plasma rings in a coaxial rail-gun (open access)

Acceleration of compact torus plasma rings in a coaxial rail-gun

We discuss here theoretical studies of magnetic acceleration of Compact Torus plasma rings in a coaxial, rail-gun accelerator. The rings are formed using a magnetized coaxial plasma gun and are accelerated by injection of B/sub theta/ flux from an accelerator bank. After acceleration, the rings enter a focusing cone where the ring is decelerated and reduced in radius. As the ring radius decreases, the ring magnetic energy increases until it equals the entering kinetic energy and the ring stagnates. Scaling laws and numerical calculations of acceleration using a O-D numerical code are presented. 2-D, MHD simulations are shown which demonstrate ring formation, acceleration, and focusing. Finally, 3-D calculations are discussed which determine the ideal MHD stability of the accelerated ring.
Date: May 16, 1985
Creator: Hartman, C. W.; Hammer, J. H. & Eddleman, J.
System: The UNT Digital Library
Management of solid waste (open access)

Management of solid waste

Compliance with the latest regulatory requirements addressing disposal of radioactive, hazardous, and sanitary solid waste requires the application of numerous qualitative and quantitative criteria in the selection, design, and operation of solid waste management facilities. Due to the state of flux of these regulatory requirements from EPA and NRC, several waste management options were identified as being applicable to the management of the various types of solid waste. This paper highlights the current regulatory constraints and the design and operational requirements for construction of both storage and disposal facilities for use in management of DOE-ORO solid waste. Capital and operational costs are included for both disposal and storage options.
Date: April 16, 1980
Creator: Thompson, W.T. & Stinton, L.H.
System: The UNT Digital Library
Inspection methods for safeguards systems at nuclear facilities (open access)

Inspection methods for safeguards systems at nuclear facilities

A project team at Lawrence Livermore National Laboratory has been developing inspection procedures and training materials for the NRC inspectors of safeguards systems at licensed nuclear facilities. This paper describes (1) procedures developed for inspecting for compliance with the Code of Federal Regulations, (2) training materials for safeguards inspectors on technical topics related to safeguards systems, such as computer surety, alarm systems, sampling techniques, and power supplies, and (3) an inspector-oriented methodology for evaluating the overall effectiveness of safeguards systems.
Date: October 16, 1981
Creator: Minichino, C. & Richard, E.W.
System: The UNT Digital Library
Three wavelength optical alignment of the Nova laser (open access)

Three wavelength optical alignment of the Nova laser

The Nova laser, presently under construction at Lawrence Livermore National Laboratory, will be capable of delivering more than 100 kJ of focused energy to an Inertial Confinement Fusion (ICF) target. Operation at the fundamental wavelength of the laser (1.05 ..mu..m) and at the second and third harmonic will be possible. This paper will discuss the optical alignment systems and techniques being implemented to align the laser output to the target at these wavelengths prior to each target irradiation. When experiments require conversion of the laser light to wavelengths of 0.53 ..mu..m and 0.35 ..mu..m prior to target irradiation, this will be accomplished in harmonic conversion crystals located at the beam entrances to the target chamber. The harmonic alignment system will be capable of introducing colinear alignment beams of all three wavelengths into the laser chains at the final spatial filter. The alignment beam at 1.05 ..mu..m will be about three cm in diameter and intense enough to align the conversion crystals. Beams at 0.53 ..mu..m and 0.35 ..mu..m will be expanded by the spatial filter to full aperture (74 cm) and used to illuminate the target and other alignment aids at the target chamber focus. This harmonic illumination system will …
Date: November 16, 1983
Creator: Swift, C. D.; Bliss, E. S.; Jones, W. A. & Seppala, L. G.
System: The UNT Digital Library
Implicit methods in particle simulation (open access)

Implicit methods in particle simulation

This paper surveys recent advances in the application of implicit integration schemes to particle simulation of plasmas. The use of implicit integration schemes is motivated by the goal of efficiently studying low-frequency plasma phenomena using a large timestep, while retaining accuracy and kinetics. Implicit schemes achieve numerical stability and provide selective damping of unwanted high-frequency waves. This paper reviews the implicit moment and direct implicit methods. Lastly, the merging of implicit methods with orbit averaging can result in additional computational savings.
Date: March 16, 1982
Creator: Cohen, B.I.
System: The UNT Digital Library
Electroweak symmetry breaking: Higgs/whatever (open access)

Electroweak symmetry breaking: Higgs/whatever

In the first of these two lectures the Higgs mechanism is reviewed in its most general form, which does not necessarily require the existence of Higgs bosons. The general consequences of the hypothesis that electroweak symmetry breaking is due to the Higgs mechanism are deduced just from gauge invariance and unitarity. In the second lecture the general properties are illustrated with three specific models: the Weinberg-Salam model, its minimal supersymmetric extension, and technicolor. The second lecture concludes with a discussion of the experiment signals for strong WW scattering, whose presence or absence will allow us to determine whether the symmetry breaking sector lies above or below 1 TeV. 57 refs.
Date: October 16, 1989
Creator: Chanowitz, Michael S.
System: The UNT Digital Library
Projections of transport scaling laws for small toroidal reactors (open access)

Projections of transport scaling laws for small toroidal reactors

Transport in present day Spheromaks is dominated by impurity radiation. Fortunately, this is largely from oxygen and carbon, not metal vapor from the walls of the vessel on plasma guns and it is expected this loss can be eliminated by improved technique. The formation and gross MHD stability properties of these plasmas are quite well understood and so the reactor predictions depend on estimates of the energy loss rates from the plasma. In the absence of significant experimental data one is driven to consider other related devices. Tokamaks show classical ion transport, scaling with 1/B/sup 2/, but anomalous electron transport which is very insensitive to magnetic field, the well known Alcator scaling. The scaling of the Spheromak to a reactor size still produces favorable Q values with these pessimistic results. The reactor is small, with power output in the 10 to 50 MW range, but this could be deployed as a multiple unit power station, with good reliability due to the duplication, or as a small power unit for a ship or remote site. It also makes an attractive test reactor for the near term.
Date: November 16, 1981
Creator: McNamara, B.
System: The UNT Digital Library
Breeder reactor fuel fabrication system development (open access)

Breeder reactor fuel fabrication system development

Significant progress has been made in the design and development of remotely operated breeder reactor fuel fabrication and support systems (e.g., analytical chemistry). These activities are focused by the Secure Automated Fabrication (SAF) Program sponsored by the Department of Energy to provide: a reliable supply of fuel pins to support US liquid metal cooled breeder reactors and at the same time demonstrate the fabrication of mixed uranium/plutonium fuel by remotely operated and automated methods.
Date: July 16, 1981
Creator: Bennett, D.W.; Fritz, R.L.; McLemore, D.R. & Yatabe, J.M.
System: The UNT Digital Library
Improving the bulk laser-damage resistance of KDP by baking and pulsed-laser irradiation (open access)

Improving the bulk laser-damage resistance of KDP by baking and pulsed-laser irradiation

Isolated bulk damage centers are produced when KDP crystals are irradiated by 1-ns 1064-nm pulses. We have tested about 100 samples and find the median threshold to be 7 J/cm/sup 2/ when the samples are irradiated only once at each test volume (1-on-1 tests). The median threshold increased to 11 J/cm/sup 2/ when the test volumes were first subjected to subthreshold laser irradiation (n-on-1 tests). We baked several crystals at temperatures from 110 to 165/sup 0/C and remeasured their thresholds. Baking increased thresholds in some crystals, but did not change thresholds of others. The median threshold of baked crystals ranged from 8 to 10 J/cm/sup 2/ depending on the baking temperature. In crystals that had been baked, subthreshold irradiation produced a large change in the bulk damage threshold, and reduced the volume density of damage centers relative to the density observed in unbaked crystals. The data are summarized in the table.
Date: September 16, 1981
Creator: Swain, J.E.; Stokowski, S.E.; Milam, D. & Rainer, F.
System: The UNT Digital Library
Inertial-confinement-fusion targets (open access)

Inertial-confinement-fusion targets

Inertial confinement fusion (ICF) targets are made as simple flat discs, as hollow shells or as complicated multilayer structures. Many techniques have been devised for producing the targets. Glass and metal shells are made by using drop and bubble techniques. Solid hydrogen shells are also produced by adapting old methods to the solution of modern problems. Some of these techniques, problems and solutions are discussed. In addition, the applications of many of the techniques to fabrication of ICF targets is presented.
Date: November 16, 1981
Creator: Hendricks, C.D.
System: The UNT Digital Library
Acceptable residual magnetic fields in the background of a gas neutralizer (open access)

Acceptable residual magnetic fields in the background of a gas neutralizer

An approximate method is described to evaluate the maximum acceptable residual magnetic field in the background of a neutral beam. 5 refs., 8 figs.
Date: October 16, 1987
Creator: Fink, J.H.
System: The UNT Digital Library
A reservoir management plan (open access)

A reservoir management plan

There are numerous documented cases of extraction of fluids from the ground causing surface subsidence. The cases include groundwater, oil and gas, as well as geothermal fluid withdrawal. A recent comprehensive review of all types of man-induced land subsidence was published by the Geological Survey of America. At the early stages of a geothermal power development project it is standard practice in most countries for an environmental impact report to be required. The possibility of geothermal subsidence has to be addressed, and usually it falls on the geophysicists and/or geologists to make some predictions. The advice given is vital for planning the power plant location and the borefield pipe and drain layout. It is not so much the vertical settlement that occurs with subsidence but the accompanying horizontal ground strains that can do the most damage to any man-made structure.
Date: June 16, 1989
Creator: Allis, R.G.
System: The UNT Digital Library
Hyper-filter-fluorescer spectrometer for fusion x-ray diagnostics (open access)

Hyper-filter-fluorescer spectrometer for fusion x-ray diagnostics

The filter-fluorescer spectrometer (FFS) is a powerful tool for measuring x-ray spectrum from high fluence x-ray sources. However, this technique is limited to energies less than 120 keV, because there are no practical absorption edges available above this energy. In this paper, we present a new method of utilizing the filter-fluorescer system for x-ray spectral measurement above 120 keV. The new apparatus is called hyper-filter-fluorescer spectrometer (HFFS).
Date: June 16, 1981
Creator: Wang, C. L.
System: The UNT Digital Library
Environmental impact of a teratogenic actinide: a case study of americium-241 (open access)

Environmental impact of a teratogenic actinide: a case study of americium-241

Americium-241 is widely used as a radiation source, but it also has some potential risk if taken into the body. Although the radiotoxicity of americium-241 is small compared to other transuranic actinides, its effects on the reproductive system and on development of the placenta are more damaging than the effects of plutonium-239. A previous report based on a worst-case scenario involving a hypothetical fire accident in a contaminated facility indicated that there could have been a significant impact on nearby residents from a unit release of americium-241 via atmospheric dispersion. However, because the facility is located in a rural region where most drinking water supplies are drawn from private wells, it is believed that deposition of americium-241 from the atmosphere might also have impacts via the groundwater pathway by infiltration of rainwater. In this analysis, a three-dimensional analytical mathematical model is used to assess several aspects of americium-241 contamination of groundwater, including radioactive transformation, advection, dispersion, and soil sorption. Simulation results indicate that no significant radiological impacts would occur to the nearby residents via the groundwater pathway. 15 refs., 2 figs., 2 tabs.
Date: October 16, 1985
Creator: Wang, J. & Yang, J.Y.
System: The UNT Digital Library
Demountable vacuum seals for fusion reactor applications (open access)

Demountable vacuum seals for fusion reactor applications

Demountable vacuum seals for fusion reactor applications must be compatible with the reactor environment, easily scalable, very reliable and readily maintained by remote handling methods. We are investigating gate valves as well as flanges in our efforts to provide such seals. They are all metal and scalable without becoming massive and require no axial fasteners. Preliminary tests on an initial 30 cm aluminum flange using no soft metal coatings or gaskets have given several vacuum tight closures. Weld fatigue of this preliminary design caused degradation of the seal with further cycling to leakage levels of 10/sup -6/ Tl/sec, which is acceptable with differential pumping for either valves or flanges. Additional flange pairs using slightly altered geometry, fabrication techniques, and seal plating materials will be tested and reported on.
Date: October 16, 1987
Creator: Batzer, T. H. & Call, W. R.
System: The UNT Digital Library