3-D hybrid PIC code to model the tilt mode in FRCs (open access)

3-D hybrid PIC code to model the tilt mode in FRCs

The results from QN3D are presented. QN3D is a 3-dimensional hybrid particle-in-cell code designed to run efficiently on the Cray-2 Multiprocessor. The chief application has been to the tilt mode instability in FRCs. QN3D accepts as input, the magnetic field, the ion particle density and the ion temperature on a two-dimensional r-z grid. These quantities are interpolated to the rest of the cartesian grid under the assumption of azimuthal symmetry. The particles are initialized with random numbers chosen according to the particle distributions input from the equilibrium code. The runs done here used equilibria computed by EQV, a kinetic equilibrium code.
Date: June 1, 1987
Creator: Horowitz, E. J. & Shumaker, D. E.
System: The UNT Digital Library
Acceleration to hypervelocities using minimum energy concepts (open access)

Acceleration to hypervelocities using minimum energy concepts

Experiments have begun at Los Alamos to assess the potential of using spheromaks to transfer energy from large, slow moving metal walls to much smaller, faster moving less massive walls so as to achieve hypervelocities in the 20 to 60 km/s range. A large plate transfers energy to the spheromak during a slow compression. The spheromak then releases this energy in a much shorter time to the small plate, accelerating it to much higher velocity. It has been estimated that velocity gains in excess of 4 (V/sub final/ ..-->.. 20 km/s) can be achieved in a practical single stage experiment.
Date: June 1, 1987
Creator: Marklin, G.
System: The UNT Digital Library
Adiabatic supernova expansion into the circumstellar medium (open access)

Adiabatic supernova expansion into the circumstellar medium

We perform one dimensional numerical simulations with a Lagrangian hydrodynamics code of the adiabatic expansion of a supernova into the surrounding medium. The early expansion follows Chevalier's analytic self-similar solution until the reverse shock reaches the ejecta core. We follow the expansion as it evolves towards the adiabatic blast wave phase. Some memory of the earlier phases of expansion is retained in the interior even when the outer regions expand as a blast wave. We find the results are sensitive to the initial configuration of the ejecta and to the placement of gridpoints. 6 refs., 2 figs.
Date: June 8, 1987
Creator: Band, D.L. & Liang, E.P.
System: The UNT Digital Library
Aging degradation of cast stainless steels: Effects on mechanical properties (open access)

Aging degradation of cast stainless steels: Effects on mechanical properties

A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water operating conditions. Mechanical property data are presented from Charpy-impact, tensile, and J-R curve tests for several heats of cast stainless steel aged up to 10,000 h at 450, 400, 350, 320, and 290/sup 0/C. The results indicate that thermal aging increases the tensile strength and decreases the impact energy, J/sub IC/, and tearing modulus of the steels. Also, the ductile-to-brittle transition curve shifts to higher temperatures. The fracture toughness results are consistent with the Charpy-impact data, i.e., the relative reduction in J/sub IC/ is similar to the relative decrease in impact energy. The ferrite content and concentration of C in the steel have a strong effect on the overall process of low-temperature embrittlement. The low-carbon CF-3 steels are the most resistant and Mo-containing CF-8M steels are most susceptible to embrittlement. Weakening of the ferrite/austenite phase boundaries by carbide precipitates has a significant effect on the kinetics and extent of embrittlement of the high-carbon CF-8 and CF-8M steels, particularly after aging at temperatures greater than or equal to400/sup 0/C. The influence of N content and distribution of ferrite on loss of toughness …
Date: June 1, 1987
Creator: Chopra, O. K. & Chung, H. M.
System: The UNT Digital Library
Aging of Electric Motors in Nuclear Power Plants (open access)

Aging of Electric Motors in Nuclear Power Plants

Motor degradation due to aging and service wear decreases reliability and increases the potential for failure during nuclear plant accident and post accident conditions. The impact of motor failures on plant safety is an important concern among the nuclear utilities and the government agency regulating this industry. Economic impacts, relating to plant availability and safety, as well as corrective maintenance, have prompted utilities to improve their maintenance programs to mitigate such aging effects. 2 refs., 3 figs.
Date: June 1, 1987
Creator: Subudhi, Mano & Taylor, John H.
System: The UNT Digital Library
Los Alamos Transuranic Waste Size Reduction Facility (open access)

Los Alamos Transuranic Waste Size Reduction Facility

The Los Alamos Transuranic (TRU) Waste Size Reduction Facility (SRF) is a production oriented prototype. The facility is operated to remotely cut and repackage TRU contaminated metallic wastes (e.g., glove boxes, ducting and pipes) for eventual disposal at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico. The resulting flat sections are packaged into a tested Department of Transportation Type 7A metal container. To date, the facility has successfully processed stainless steel glove boxes (with and without lead shielding construction) and retention tanks. We have found that used glove boxes generate more cutting fumes than do unused glove boxes or metal plates - possibly due to deeply embedded chemical residues from years of service. Water used as a secondary fluid with the plasma arc cutting system significantly reduces visible fume generation during the cutting of used glove boxes and lead-lined glove boxes. 2 figs., 1 tab.
Date: June 1, 1987
Creator: Harper, J. & Warren, J.
System: The UNT Digital Library
An analysis of loss of offsite power with a PWR at shutdown (open access)

An analysis of loss of offsite power with a PWR at shutdown

In many Probabilistic Risk Assessments (PRAs), loss of offsite power (LOOP) when a nuclear power plant is operating was found to be a significant contributor to core damage. The purpose of this study is to provide an analysis of a loss of offsite power event that occurs while a PWR is shut down. The importance of such an analysis was recognized as part of a study to evaluate the core damage frequency due to a loss of decay heat removal capability during an outage. 5 refs., 1 fig.
Date: June 1, 1987
Creator: Chu, T. L.; Yoon, W. H. & Fitzpatrick, R. G.
System: The UNT Digital Library
Analysis of pressure, enthalpy and CO/sub 2/ transients in well BR21, Ohaaki, New Zealand (open access)

Analysis of pressure, enthalpy and CO/sub 2/ transients in well BR21, Ohaaki, New Zealand

Numerical studies are undertaken, which incorporate both double porosity and noncondensible gas effects, to determine the characteristics of the reservoir near well BR21 of Ohaaki geothermal field, New Zealand. It is shown that the application of numerical techniques to analyze two-phase well data can provide valuable information that may not otherwise be obtained. Numerical techniques allow more of the true reservoir complexities to be included, further constraining the results. The model developed adequately matches observed pressure, enthalpy and flowing CO/sub 2/ mass fraction while providing estimates of important reservoir parameters.
Date: June 1, 1987
Creator: Gaulke, S. W. & Bodvarsson, G. S.
System: The UNT Digital Library
Analysis of surface contaminants on beryllium and aluminum windows (open access)

Analysis of surface contaminants on beryllium and aluminum windows

An effort has been made to document the types of contamination which form on beryllium window surfaces due to interaction with a synchrotron radiation beam. Beryllium windows contaminated in a variety of ways (exposure to water and air) exhibited surface powders, gels, crystals and liquid droplets. These contaminants were analyzed by electron diffraction, electron energy loss spectroscopy, energy dispersive x-ray spectroscopy and wet chemical methods. Materials found on window surfaces include beryllium oxide, amorphous carbon, cuprous oxide, metallic copper and nitric acid. Aluminum window surface contaminants were also examined.
Date: June 1, 1987
Creator: Gmur, N.F.
System: The UNT Digital Library
Application of a two fluid theoretical plasma transport model on current tokamak reactor designs. [TIBER II Engineering Test Reactor] (open access)

Application of a two fluid theoretical plasma transport model on current tokamak reactor designs. [TIBER II Engineering Test Reactor]

In this work, the new theoretical transport models to TIBER II design calculations are described and the results are compared with recent experimental data in large tokamaks (TFTR, JET). Tang's method is extended to a two-fluid model treating ions and electrons separately. This allows for different ion and electron temperatures, as in recent low-density experiments in TFTR, and in the TIBER II design itself. The discussion is divided into two parts: (1) Development of the theoretical transport model and (2) calibration against experiments and application to TIBER II.
Date: June 1, 1987
Creator: Ibrahim, E. & Fowler, T.K.
System: The UNT Digital Library
Beam dynamics in the SLC final focus system (open access)

Beam dynamics in the SLC final focus system

The SLC luminosity is reached by colliding beams focused to about 2 ..mu..m transverse sizes. The Final Focus System (FFS) must enable, beyond its basic optical design, the detection and correction of errors accumulated in the system. In this paper, after summarizing the design, we review the sensitivity to such errors and the ability to correct them. The overall tuning strategy involves three phases: single beam spot minimization, steering the beams in collision and luminosity optimization with beam-beam effects.
Date: June 1, 1987
Creator: Bambade, P.S.
System: The UNT Digital Library
Calculation of MCPR (minimum critical power ratio) for BWR transients using the BNL plant analyzer (open access)

Calculation of MCPR (minimum critical power ratio) for BWR transients using the BNL plant analyzer

The critical power ratio (CPR) is used for determining the thermal limits of boiling water reactors. In this study, critical power ratios for a series of transients run on the Brookhaven Plant Analyzer (BPA) (1) have been calculated. The transients include nominal base case simulations, simulations with variations in relief valve setpoints and the number of failed feedwater heaters, simulations at the 100% power, 75% flow point on the extended load line of the MEOD, and a simulation with partial feedwater heating. The plant represented with the BPA is a BWR/4 rated at 3293 MW with a 6.38 m (251'') vessel. Data were obtained by the Plant Analyzer Development Group at BNL from a variety of sources describing the Browns Ferry Plant.
Date: June 1, 1987
Creator: Horak, W. C. & Diamond, D. J.
System: The UNT Digital Library
Combined seismic and hydraulic method of modeling flow in fractured low permeability rocks (open access)

Combined seismic and hydraulic method of modeling flow in fractured low permeability rocks

Modeling flow of ground water in hard rocks where a network of fractures provides the dominant flow paths is a major problem. This paper summarizes a program of investigations currently underway in this laboratory to characterize the geometry of fractured rocks and develop methods of handling flow in such systems. Numerical models have been developed to investigate flow behavior in two- and three-dimensional fracture networks. The results demonstrate the insights that can be gained from modeling studies of fractured rocks. A key problem is gathering the necessary data on fracture geometry. Investigations have been started to determine how vertical seismic profiling (VSP) might be improved and applied to this problem. A VSP experiment in The Geysers geothermal field in northern California, where fracture orientation is known, produced shear wave splitting and velocity anisotropy in agreement with theory. The results suggest the potential application of 3-component, multi-source VSP data in determining fracture orientation and average spacing. We believe a combination of seismic and hydraulic methods can greatly enhance an understanding of fluid flow and transport in low permeability rock systems where fractures provide the dominant paths. 40 refs, 16 figs., 4 tabs.
Date: June 1, 1987
Creator: Witherspoon, P. A.; Long, J. C. S.; Majer, E. L. & Myer, L. R.
System: The UNT Digital Library
Composite weak bosons at supercolliders (open access)

Composite weak bosons at supercolliders

Following a brief survey of nongauge interactions of composite W and Z from a theoretical viewpoint, we point out some of conspicuous signatures of compositeness at supercolliders, in particular W..gamma.. and Z..gamma.. production through q anti q by interactions of dimension six. In these processes, a suppression factor 1/..lambda../sup 2/ due to compositeness scale ..lambda.. is largely compensated by longitudinal polarizations of W and Z, allowing us to probe up to high values of ..lambda... 10 refs., 3 figs.
Date: June 1, 1987
Creator: Suzuki, Mahiko
System: The UNT Digital Library
A conceptual design of Final Focus Systems for linear colliders (open access)

A conceptual design of Final Focus Systems for linear colliders

Linear colliders are a relatively recent development in the evolution of particle accelerators. This report discusses some of the approaches that have been considered for the design of Final Focus Systems to demagnify the beam exiting from a linac to the small size suitable for collisions at the interaction point. The system receiving the most attention is the one adopted for the SLAC Linear Collider. However, the theory and optical techniques discussed should be applicable to the design efforts for future machines.
Date: June 1, 1987
Creator: Brown, K.L.
System: The UNT Digital Library
Correlation between annealing and irradiation behavior of dispersion fuels: Final report. [U/sub 3/Si/sub x/, U/sub 6/Mn, U/sub 3/SiAl, U/sub 6/Fe, U/sub 75/Ga/sub 10/Si/sub 15/, U/sub 75/Ga/sub 15/Ge/sub 10/] (open access)

Correlation between annealing and irradiation behavior of dispersion fuels: Final report. [U/sub 3/Si/sub x/, U/sub 6/Mn, U/sub 3/SiAl, U/sub 6/Fe, U/sub 75/Ga/sub 10/Si/sub 15/, U/sub 75/Ga/sub 15/Ge/sub 10/]

Studying the effects of annealing of scaled-down dispersion fuel plates is an important part of the data base for fuel performance. One of the most critical aspects of fuel performance is the stability of a fuel/matrix dispersion which is usually measured by volumetric changes of the fuel zone. A correlation has been proposed that fission-induced amorphization is responsible for the instability of the fuel and that such transformations can be predicted by the thermodynamic properties of the fuel. It is proposed that annealing studies may be used as a screening test for new fuels for which no thermodynamic properties have been measured and/or no irradiation data are available. Estimations of irradiation performance could be obtained faster and without the expense of irradiating the fuels under investigation. Miniature fuel plates were fabricated by standard procedures and annealed at 400/sup 0/C for up to 1981 hrs in a resistance wound furnace. At periodic intervals the plates were removed and the fuel zone volumes were calculated based on immersion density measurement data. 7 refs., 1 tab.
Date: June 1, 1987
Creator: Wiencek, T. C. & Domagala, R. F.
System: The UNT Digital Library
A creep measurement of unidirectional epoxy-fiberglass rod (open access)

A creep measurement of unidirectional epoxy-fiberglass rod

A creep measurement was made to prove the capability of a unidirectionally reinforced, epoxy-fiberglass rod to hold stable dimensions in compression over a 10 year period, during which operating temperatures of 40/sup 0/C (104/sup 0/F) could occur. This material has a high modulus of elasticity in tension and compression (approx.6 x 10/sup 6/ psi) and strengths in excess of 100,000 psi. Its high strength and low thermal conductivity in the range from 300K to cryogenic temperatures make it ideally suited for cryogenic supports. The sample was tested in compression at 52 MPa (7500 psi) at 40/sup 0/C for 1000 hours. The measured fractional deflection due to creep after 1000 hours was 3 x 10/sup -5/. Extrapolation of the data to 10 years under the test load of 52 MPa predicts a fractional deflection of 6 x 10/sup -5/. The low stress level was appropriate to a conservative design for the dipole magnet support struts for the Superconducting Super Collider cryostat (alternate design), an application requiring long-term accurate positioning of the magnet. The struts carry the weight of the magnet, at liquid helium temperature, to the base at ambient temperature. An elevated ambient standby or storage temperature is the critical temperature …
Date: June 1, 1987
Creator: Munshi, N. A. & Wolgast, R. C.
System: The UNT Digital Library
CRITIC-I: Instrumented lithium oxide irradiation: Part 1, Lithium oxide fabrication and characteristics (open access)

CRITIC-I: Instrumented lithium oxide irradiation: Part 1, Lithium oxide fabrication and characteristics

Fine-grained, sinterable lithium oxide powder was prepared by high-temperature vacuum calcination of molten lithium carbonate. The product was ball milled, cold pressed, and fired in an oxygen atmosphere. The fired density, grain size, and surface roughness varied widely with firing schedule. Most variations were attributed to moisture content. Rings of high-density, sintered lithium oxide will be used in an in-reactor experiment to measure tritium release. 2 refs., 8 figs., 1 tab.
Date: June 1, 1987
Creator: Applegate, D.S. & Poeppel, R.B.
System: The UNT Digital Library
Detecting beauty baryons and heavy beauty mesons with the J/PSI trigger (open access)

Detecting beauty baryons and heavy beauty mesons with the J/PSI trigger

The combination of a vertex detector with a J/PSI trigger should enable one to measure the masses and lifetimes of various beauty baryons and heavy beauty mesons at the SSC or Tevatron II.
Date: June 1, 1987
Creator: Bigi, I. I. & Clavelli, L.
System: The UNT Digital Library
Diagnostic technique for monitoring high temperature plasma dynamics (open access)

Diagnostic technique for monitoring high temperature plasma dynamics

A preliminary design for the adaptation of a pinhole experiment (PINEX) technique to the monitoring of the dynamics of high temperature plasmas is described. Specifically, this imaging technique uses a thick aperture, an efficient radiation converter, and highly intensified television cameras to provide real-time viewing of radiation sources such as the neutron emissions from d-d and d-t fusion reactions in controlled thermonuclear research devices. The neutron emission strengths, R approx. 5 x 10/sup 15/ n/s, recently achieved at the Tokamak Fusion Test Reactor (TFTR) and the Joint European Torus (JET) should be sufficient for 3 to 6-cm spatial resolution and 10 to 100-ms time resolution using such a system. Such information should be useful for on-line optimization of the plasma and for quantitative evaluation of its performance.
Date: June 1, 1987
Creator: Lumpkin, A. H. & Pappas, D. S.
System: The UNT Digital Library
Diffusion studies in amorphous NiZr alloys (open access)

Diffusion studies in amorphous NiZr alloys

Tracer impurity and self diffusion measurements have been made on amorphous (a-) NiZr alloys using radioactive tracer, Secondary Ion Mass Spectrometry and Rutherford backscattering techniques. The temperature dependence of diffusion in a-NiZr can be represented in the form D = D/sub 0/exp(-Q/kT), with no structural relaxation effects being observed. The mobility of an atom in a-NiZr increased dramatically with decreasing atomic radius of the diffusing atom and also with decreasing Ni content for Ni concentrations below approx. =40 at. %. These diffusion characteristics in a-NiZr are remarkably similar to those in ..cap alpha..-Zr and ..cap alpha..-Ti. These mechanisms assume that Zr and Ti provide a close packed structure, either crystalline or amorphous, through which small atoms diffuse by an interstitial mechanism and large atoms diffuse by a vacancy mechanism. 12 refs., 2 figs., 2 tabs.
Date: June 1, 1987
Creator: Hahn, H.; Averback, R. S.; Hoshino, K. & Rothman, S. J.
System: The UNT Digital Library
Economics of Induction Linac Drivers for Radiation Sources (open access)

Economics of Induction Linac Drivers for Radiation Sources

Recent developments in high reliability components for linear induction accelerators (LIA) make possible the use of LIAs as large-scale, economical sources of radio-frequency (rf) power for many applications. One particularly attractive example of interest to high energy physicists is a ''two-beam accelerator'' version of a linear e/sup +/-e/sup -/ collider at TeV energies in which the LIA is configured as a monolithic relativistic klystron operating at 10 to 12 GHz. Another example of keen interest to the fusion community is the use of the LIA to drive a free-electron laser operating at 200 to 500 GHz for use in heating fusion plasma via electron resonance cyclotron heating. This paper briefly describes several potential uses of LIA radiation sources. It discusses the physical basis for scaling our present experience with LIAs to the operating characteristics applicable to large-scale sources of rf power and synchrotron radiation. 14 refs., 6 figs., 1 tab.
Date: June 15, 1987
Creator: Barletta, W. A.
System: The UNT Digital Library
Effects of steam-liquid counterflow on pressure transient data from two-phase geothermal reservoirs (open access)

Effects of steam-liquid counterflow on pressure transient data from two-phase geothermal reservoirs

Numerical studies are performed to investigate the effects localized feedzones on the pressure transients in two-phase reservoirs. It is shown that gravity effects can significantly affect the pressure transients, because of the large difference in the density of liquid water and vapor. Production from such systems enhances steam/liquid water counterflow and expands the vapor-dominated zone at the top of the reservoir. Subcooled liquid regions develop in the center of the reservoir due to gravity drainage of cooler liquid water. The vapor zone will act as a constant pressure boundary and help stabilize the decline in the system. It is shown that the pressure transients at observation wells depend greatly on the location (depth) of the major feedzone; if this is not accounted for, large errors in deduced reservoir properties will result. At shallow observation points pressures may actually increase as a result of enhanced steam upflow due to production at a deep feedzone. 12 refs., 17 figs.
Date: June 1, 1987
Creator: Bodvarsson, G.S.; Cox, B.L. & Ripperda, M.
System: The UNT Digital Library
Electronic excitation and ion source optimization (open access)

Electronic excitation and ion source optimization

The electronic excitation cross sections leading to H/sub 2/(v'') molecules are discussed. The effect of shortening the length of the first chamber of a tandem configuration for the purpose of reducing the atomic concentration is shown to enhance the extracted current density.
Date: June 29, 1987
Creator: Hiskes, J.R. & Lietzke, A.F.
System: The UNT Digital Library