54 Matching Results

Search Results

Collective behavior in recent laser-plasma experiments

Description: The absorption of 1.06 ..mu.. light focused on small C/sub 8/H/sub 8/ discs has been measured in the intensity range of 10/sup 15/ - 10/sup 17/ W/cm. The data confirms the importance of collective plasma effects in determining the absorption of intense light. The measured absorption efficiencies are in the range of 30 to 40 percent, and the scattered light has a polarization dependence. The measured absorptions are shown to be inconsistent with classical inverse bremsstrahlung. Both the magnitude of the absorption and the observed polarization dependence of the scattered light are shown to be consistent with recent calculations of light absorption via collective processes. Comparisons are made, and improved models of the light absorption are discussed with reference to the data. In addition, the heated electron energies deduced from the x-ray data are consistent with those expected via collective processes.
Date: June 7, 1976
Creator: Kruer, W. L.; Haas, R. A.; Mead, W. C.; Phillion, D. W. & Rupert, V. C.
Partner: UNT Libraries Government Documents Department

Cylindrical and spherical solitons. [Soliton observation in cold single-species plasma]

Description: The recent prediction and observation of cylindrical and spherical ion acoustic solitons in a cold, single species plasma are reviewed. The properties of these higher dimensional solitons are quite different from their planar counterpart since the amplitude increases, the width decreases, and the propagation speed increases as the soliton moves inward. Although the results for two- and three-dimensional solitons are obtained numerically, early time solutions can be found analytically and compared with numerical solutions. An interesting phenomenon, which is an integral part of these higher dimensional solitons, is the presence of a wake. Although the amplitude of this wake is very small, it can carry considerable momentum since it extends over a large spatial region.
Date: June 1, 1976
Creator: Maxon, S.
Partner: UNT Libraries Government Documents Department

Reactor scram experience for shutdown system reliability analysis. [BWR; PWR]

Description: Scram experience in a number of operating light water reactors has been reviewed. The date and reactor power of each scram was compiled from monthly operating reports and personal communications with the operating plant personnel. The average scram frequency from ''significant'' power (defined as P/sub trip//P/sub max greater than/ approximately 20 percent) was determined as a function of operating life. This relationship was then used to estimate the total number of reactor trips from above approximately 20 percent of full power expected to occur during the life of a nuclear power plant. The shape of the scram frequency vs. operating life curve resembles a typical reliability bathtub curve (failure rate vs. time), but without a rising ''wearout'' phase due to the lack of operating data near the end of plant design life. For this case the failures are represented by ''bugs'' in the plant system design, construction, and operation which lead to scram. The number of scrams would appear to level out at an average of around three per year; the standard deviations from the mean value indicate an uncertainty of about 50 percent. The total number of scrams from significant power that could be expected in a plant designed for a 40-year life would be about 130 if no wearout phase develops near the end of life.
Date: June 1, 1976
Creator: Edison, G. E.; Pugliese, S. L. & Sacramo, R. F.
Partner: UNT Libraries Government Documents Department

Potential for fissile breeding with the fusion-fission hybrid reactor

Description: The general features of the mirror reactor design are discussed. Details of the blanket-coil geometry are shown. The inside face of the blanket segments are divided into individual pressure vessels. These submodules contain fissile breeding material located directly behind the first wall, a fusile breeding material behind the fertile breeder, and then coolant inlet and outlet plena. Two blankets are examined and compared in this study. One contains natural uranium plus 7 wt. percent Mo, the second contains thorium metal. The performance of these blankets is discussed. (MOW)
Date: June 10, 1976
Creator: Bender, D. J. & Lee, J. D.
Partner: UNT Libraries Government Documents Department

Design techniques and measured performance for a uniformly-pumped 4-cm diameter rod amplifier

Description: A solid-state laser rod amplifier of moderate aperture achieving a high degree of spatial gain uniformity has been constructed and its performance evaluated. Digital and analogue techniques were used to optimize the amplifier design for performance in a laser fusion application. Results of simple 2-D computer simulations and experimental evaluations of amplifier performance are presented.
Date: June 30, 1976
Creator: Linford, G. J. & Yarema, S. M.
Partner: UNT Libraries Government Documents Department

Tritium containment and blanket design challenges for a 1 GWe mirror fusion central power station

Description: Tritium containment and removal problems associated with the blanket and power-systems for a mirror fusion reactor are identified and conceptual process designs are devised to reduce emissions to the environment below 1 Ci/day. The blanket concept development proceeds by starting with this emission goal of 1 Ci/day and working inward to the blanket. At each decision point, worker safety, operational labor costs, and capital cost tradeoffs are contrasted. The conceptual design uses air for the reactor hall with a continuous catalytic oxidizer-molecular sieve adsorber cleanup system to maintain a 40 ..mu..Ci/m/sup 3/ tritium level (5 ..mu..Ci/m/sup 3/ HTO) against 180 Ci/day leakage from reactor components, energy recovery systems, and process piping. This blanket contains submodules with Li/sub 2/Be/sub 2/O/sub 3/--Be for tritium breeding and submodules with Be for mostly energy production. Tritium production in both is handled by separately containing this breeding material and scavenging this container with lithium vapor-doped helium gas stream.
Date: June 1, 1976
Creator: Galloway, T. R.
Partner: UNT Libraries Government Documents Department

Minicomputer based, controlled materials information system

Description: The LLL, Materials Management Group and Data Processing Services have developed a transaction-oriented, minicomputer system for the management of the Laboratory's controlled materials. The system consists of a multi-vendor hardware system designed for ease of operation, maximum reliability, and quick response and the requirements imposed on the hardware and software systems are discussed.
Date: June 1, 1976
Creator: Roberts, N.; Jessen, T.; Meadors, O. & Seibel, D.
Partner: UNT Libraries Government Documents Department

X-ray instrumentation in the LLL Laser-Fusion Program

Description: The LLL Laser-Fusion Program includes an active experimental effort to measure the distributions in energy, space and time of pulses of soft x-rays (.2 to 10 keV) radiated by laser-induced plasmas. Requirements for high resolution in these measurements clearly preclude the use of conventional x-ray diagnostic techniques. The following examples from our program of advanced x-ray instrument development are described. (1) Wavelength-dispersive spectrographs with fractional-electron volt resolution at several keV and imaging systems with 3 micron resolution over a 100 micron source. (2) Advanced solid state x-ray sensors that recover data from these instruments in a more expedient manner than photographic film. (3) Microcomputer-controlled stand-alone spectrograph data systems and minicomputer-based integrated systems that can deal with the large array of data generated by the high resolution instruments. (4) An electrostatically-deflected x-ray streak camera with moderate spectral and spatial resolution and a timing resolution of better than 15 ps.
Date: June 23, 1976
Creator: Koppel, L. N.
Partner: UNT Libraries Government Documents Department

MX magnet system. [Electrical and engineering design characteristics]

Description: A conceptual drawing of the MX experiment is given. The central feature of the MX is a large superconducting magnet. The magnet parameters and conductor parameters are listed. The electrical and engineering design of the magnet is given.
Date: June 24, 1976
Creator: Bulmer, R. H.; Calderon, M. O.; Cornish, D. N.; Kozman, T. A. & Sackett, S. J.
Partner: UNT Libraries Government Documents Department

Fueling, heating, and leaking of plasma in mirror reactors

Description: The principles of mirror machine confinement are reviewed with emphasis on the physical process of neutral beam injection and plasma end leakage. The characteristics of efficient neutral beam injectors and direct energy convertors for the plasma and leakage are described.
Date: June 25, 1976
Creator: Carlson, G. A. & Moir, R. W.
Partner: UNT Libraries Government Documents Department

Measurements of neutron-induced fission cross-section ratios involving isotopes of uranium and plutonium. [0. 001 to 30 MeV, cross sections]

Description: A procedure, called the threshold cross section method was applied to our experimental data involving four uranium (/sup 233/U /sup 234/U, /sup 236/U, and /sup 238/U) and five plutonium (/sup 239/Pu, /sup 240/Pu, /sup 241/Pu, /sup 242/Pu, and /sup 244/Pu) isotopes to determine ratios of fission cross sections relative to /sup 235/U. The data were gathered using ionization fission chambers and the time-of-flight technique at the LLL 100-MeV electron linear accelerator: measurements span the neutron energy range of 0.001 to 30 MeV. Experimental uncertainties common to past measurements were either eliminated or significantly reduced in this study by use of the threshold method, thereby making higher accuracies possible. The cross section ratios are absolute in the sense that they do not depend on the work of others. Results from our ratios involving /sup 233/U, /sup 235/U, /sup 238/U, and /sup 239/Pu are used to illustrate this method.
Date: June 8, 1976
Creator: Behrens, J. W. & Carlson, G. W.
Partner: UNT Libraries Government Documents Department

Spectrophotometric determination of uranium in nuclear waste

Description: A spectrophotometric method for determining uranium in nuclear waste was developed using 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (bromo-PADAP). By extracting the color into Aliquat-336 it was possible to accurately measure U at the 1 ..mu..g level. No significant interferences were observed from 34 interfering ions when a tri-n-octylphosphine oxide (TOPO) pre-extraction of U was used. The effect of pH, color development time, bromo-PADAP concentration, and Aliquat-336 concentration were determined. The method was applied to the analysis of alkaline solutions, filtered solids, sludges, and salt cake nuclear waste forms. The standard deviation for the method with a TOPO pre-extraction was +-3.7 percent.
Date: June 1, 1976
Creator: Winters, W. I.
Partner: UNT Libraries Government Documents Department

Proceedings of a seminar on the potential for LMFBR boiling detection by acoustic/neutronic monitoring, Argonne, Illinois, April 8--9, 1976

Description: A seminar involving ten technical presentations by principal investigators was held to assess the current scope of ERDA-sponsored programs to determine the feasibility of sodium-boiling detection in LMFBRs and to establish areas in need of additional research and development. The consensus was that (1) feasibility of boiling detection by acoustic, neutronic, and acoustic/neutronic monitors has been demonstrated in U.S. and European programs; (2) additional research and development is needed in areas of reactor noise, cavitation, and the effects of noncondensible gases on sound source levels and transmission; (3) the role of acoustic/neutronic monitors from the standpoint of reactor surveillance rather than reactor safety is a viable approach to be adapted; and, in particular (4) a need exists for an operational LMFBR demonstration system. Each paper has been separately abstracted and indexed. (DG)
Date: June 1, 1976
Creator: Carey, W. M. & Albrecht, R. W.
Partner: UNT Libraries Government Documents Department

Some techniques for the solidification of radioactive wastes in concrete

Description: Some techniques for the solidification of radioactive wastes in concrete are discussed. The sources, storage, volume reduction, and solidification of liquid wastes at Brookhaven National Laboratory (BNL) using the cement-vermiculite process is described. Solid waste treatment, shipping containers, and off-site shipments of solid wastes at BNL are also considered. The properties of low-heat-generating, high-level wastes, simulating those in storage at the Savannah River Plant (SRP), solidified in concrete were determined. Polymer impregnation was found to further decrease the leachability and improve the durability of these concrete waste forms.
Date: June 1, 1976
Creator: Colombo, P & Neilson, R Jr
Partner: UNT Libraries Government Documents Department

Use of program GEOTHM to design and optimize geothermal power cycles

Description: The Lawrence Berkeley Laboratory program GEOTHM has been under development for nearly two years. GEOTHM will design and optimize a wide variety of thermodynamic cycles. The most recent improvements in the GEOTHM program are included. These improvements include: a model for concentrated saline brines and a single step cycle optimization process. Geothermal power cycles are given as examples.
Date: June 1, 1976
Creator: Pines, H. S. & Green, M. A.
Partner: UNT Libraries Government Documents Department

Calculation of magnetic fields for engineering devices

Description: The methodology of magnet technology and its application to various engineering devices are discussed. Magnet technology has experienced a rigid growth in the past few years as a result of the advances made in superconductivity, numerical methods and computational techniques. Included are discussions on: (1) mathematical models for solving magnetic field problems; (2) the applicability, usefulness, and limitations of computer programs that utilize these models; (3) examples of application in various engineering disciplines; and (4) areas where further contributions are needed.
Date: June 1, 1976
Creator: Colonias, J. S.
Partner: UNT Libraries Government Documents Department

Barrelet zeros and elastic. pi. /sup +/p partial waves. [1. 2 to 2. 2 GeV, partial-wave amplitudes]

Description: A procedure is proposed for constructing low-order partial-wave amplitudes from a knowledge of Barrelet zeros near the physical region. The method is applied to the zeros already obtained for elastic ..pi../sup +/p scattering data between 1.2 and 2.2 GeV cm energies. The partial waves emerge with errors that are straight-forwardly related to the accuracy of the data and satisfy unitarity without any constraint being imposed. There are significant differences from the partial waves obtained by other methods; this can be partially explained by the fact that no previous partial-wave analysis has been able to solve the discrete ambiguity. The cost of the analysis is much less.
Date: June 1, 1976
Creator: Chew, D. M. & Urban, M.
Partner: UNT Libraries Government Documents Department

Optimizing kaon production

Description: Kaon production data is examined with the view toward producing high quality beams in the future. Emphasis is placed upon the low momentum region, below 1 GeV/c, where the behavior of the kaon momentum spectrum is shown to be dominated by strongly momentum dependent kinematic factors. No complete experimental survey of production cross sections at different incident proton energies exists from a single apparatus. Information on relative production yields for different proton energies is important in the choice of parameters for an accelerator constructed primarily as a source of kaons. Data from different accelerators do exist and have been compiled. The key element in understanding how to present the data from different laboratories in a consistent way is an analysis of the effects of target material, target size, and production angle. This analysis not only enables a unification of the data but also indicates simple, useful and powerful principles about optimizing target efficiency. A summary is presented of existing kaon production facilities in the United States. These are all at proton accelerators. The possibility of using electron accelerators as kaon sources is examined. It is found that secondary beam fluxes can be obtained at electron linacs which are comparable to those obtained at proton synchrotrons.
Date: June 1, 1976
Creator: Berley, D.
Partner: UNT Libraries Government Documents Department

Geothermal studies in northern Nevada

Description: The Lawrence Berkeley Laboratory (LBL) and University of California (UCB), under the auspices of the U.S. Energy Research and Development Administration, are conducting field studies at potential geothermal resource areas in north-central Nevada. The goal of the LBL-UCB program is to develop and evaluate techniques for the assessment of the resource potential of liquid-dominated systems. Field studies presently being conducted in northern Nevada incorporate an integrated program of geologic, geophysical, and geochemical surveys leading to heat flow measurements, and eventually to deep (1.5 to 2 km) confirmatory drill holes. Techniques evaluated include geophysical methods to measure contrasts in electrical resistivity and seismic parameters. Geochemical studies have emphasized techniques to disclose the pathways of water from its meteoric origin into and through the hydrothermal systems. Geochemical and radiometric analyses also help to provide a baseline upon which the effects of future geothermal development may be superimposed.
Date: June 1, 1976
Creator: Wollenberg, H. A.
Partner: UNT Libraries Government Documents Department

Computerized mass spectrometer data system at LLL

Description: The data systems on the three mass spectrometers at LLL are computer-controlled, pulse-counting systems synchronized to a repeatedly swept magnetic field. The data are accumulated in the memory of the computer or in a Nuclear Data ND 180 in a multi-scaler mode of operation. This mode of data acquisition allows a continuous check of the background stability and makes tune-up easier. But the main benefit is a reduction in the required ion emission rate stability. By the use of standards to set the system dead time, we have been able to utilize the sensitivity of a pulse counting system without the expense of exotic equipment.
Date: June 30, 1976
Creator: Friesen, R. D. & Dupzyk, R. J.
Partner: UNT Libraries Government Documents Department

Multiple sine wave excitation of a hard spring oscillator

Description: The vibration testing of non-linear systems has not received much attention in the literature. Frequently, linear procedures are used in the hope that large differences between the linear and non-linear responses will not occur. This may be valid for certain small ranges of the non-linearity and for a single harmonic component excitation. However, for multi-component periodic inputs, there is very little guidance in the literature for even a qualitative evaluation of the probable response. With multi-component periodic inputs, it has been shown that sub-combination frequencies can occur in cubic non-linear systems. Under these conditions, large responses can develop. The critical nature of the development of the large response has not been discussed. This is the subject of this paper. The qualitative response of a two component sine wave applied to a hard spring oscillator is shown.
Date: June 1, 1976
Creator: Curreri, J R & Bezler, P
Partner: UNT Libraries Government Documents Department

Some aspects of vibration control support design

Description: The effectiveness and optimal placement of vibration control supports in reactor piping systems is discussed. Transfer matrix methods were used to evaluate some typical simple systems and the results are presented.
Date: June 1, 1976
Creator: Bezler, P. & Curreri, J. R.
Partner: UNT Libraries Government Documents Department