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An Aerial Radiological survey of the Alvin W. Vogtle Nuclear Plant and surrounding area, Waynesboro, Georgia: Date of survey: August--September 1988

Description: An Aerial Radiological Survey was conducted during the period of August 24 to September 14, 1988 over an area of approximately 310 square kilometers (120 square miles) surrounding the Alvin W. Vogtle Nuclear Plant. The Vogtle Nuclear Plant is located near Augusta, Georgia, along the Savannah River and adjacent to the Savannah River Site (SRS). Several anomalous areas were identified in the portion of the survey extending into the SRS perimeter. The dominant isotopes found in these areas were cesium-137 and cobalt-60. All of these man-made anomalies identified by the aerial measurements were attributed to SRS processing. For the remainder of the survey area, the inferred radiation exposure rates generally varied from 6 to 10 microroentgens per hour ({mu}R/h), which was found to be due to naturally occurring uranium, thorium, and radioactive potassium gamma emitters. The reported exposure rate values included an estimated cosmic ray contribution of 3.6 {mu}R/h. Soils samples and pressurized ion chamber measurements were obtained at three locations within the survey boundaries to support the aerial data. The exposure rate values obtained from these groundbased measurements were in agreement with the corresponding inferred aerial values. 6 refs., 13 figs., 4 tabs.
Date: September 1, 1990
Partner: UNT Libraries Government Documents Department

MGA (Multi-Group Analysis): A gamma-ray spectrum analysis code for determining plutonium isotopic abundances

Description: Nondestructive measurements of x-ray and gamma-ray emissions can be used to analyze a sample for plutonium. This report describes the methods and algorithms we have developed for analyzing gamma-ray spectra obtained by using a germanium detector system to accurately determine the relative abundances of various actinide isotopes in a sample. Our methodology requires no calibrations and can be used to measure virtually any size and type of plutonium sample. Measurement times can be as short as a few minutes; measurements are frequently accurate to within 1%. Our methods have been programmed into a computerized analysis code called MGA (Multi-Group Analysis). Our current versions can be run on personal computers (IBM type) and on the DEC VAX microcomputer. Spectral analysis times are usually far less than a minute. 28 refs., 26 figs., 1 tab.
Date: April 3, 1990
Creator: Gunnink, R
Partner: UNT Libraries Government Documents Department

Far-field dispersal modeling for fuel-air-explosive devices

Description: A computer model for simulating the explosive dispersal of a fuel agent in the far-field regime is described and is applied to a wide variety of initial conditions to judge their effect upon the resulting fuel/air cloud. This work was directed toward modeling the dispersal process associated with Fuel-Air-Explosives devices. The far-field dispersal regime is taken to be that time after the initial burster charge detonation in which the shock forces no longer dominate the flow field and initial canister and fuel mass breakup has occurred. The model was applied to a low vapor pressure fuel, a high vapor pressure fuel and a solid fuel. A strong dependence of the final cloud characteristics upon the initial droplet size distribution was demonstrated. The predicted fuel-air clouds were highly non-uniform in concentration. 18 refs., 86 figs., 4 tabs.
Date: May 1, 1990
Creator: Glass, M.W.
Partner: UNT Libraries Government Documents Department

Numerical simulation of the mitigating effects of an LNG vapor fence

Description: FEM3A, a fully three-dimensional numerical model for simulating the atmospheric dispersion of heavy gases involving complex geometry, has been used to investigate the mitigating effects of a vapor fence for LNG storage areas. In this paper, a brief description of the numerical model used to perform such calculations is given, the problem being simulated is described, and an intercomparison among the results from numerical simulations (with and without the vapor fence) and field data (with vapor fence) is made. The numerical results indicate that, with the present fence configuration, the maximum concentration on the cloud centerline was reduced by a factor of two or more within 250 m behind the fence, and the downwind distance to the 2.5% concentration was reduced from 365 m to 230 m. However, a vapor fence could also cause the vapor cloud to linger considerably longer in the source area, thus increasing the potential for ignition and combustion within the vapor fence and the area nearby over time. 8 refs., 10 figs.
Date: May 1, 1990
Creator: Chan, S.T.
Partner: UNT Libraries Government Documents Department

Models for multimegawatt space power systems

Description: This report describes models for multimegawatt, space power systems which Sandia's Advanced Power Systems Division has constructed to help evaluate space power systems for SDI's Space Power Office. Five system models and models for associated components are presented for both open (power system waste products are exhausted into space) and closed (no waste products) systems: open, burst mode, hydrogen cooled nuclear reactor -- turboalternator system; open, hydrogen-oxygen combustion turboalternator system; closed, nuclear reactor powered Brayton cycle system; closed, liquid metal Rankine cycle system; and closed, in-core, reactor therminonic system. The models estimate performance and mass for the components in each of these systems. 17 refs., 8 figs., 15 tabs.
Date: June 1, 1990
Creator: Edenburn, M.W.
Partner: UNT Libraries Government Documents Department

F111 Crew Escape Module pilot parachute

Description: A successfully deployment of a parachute system highly depends on the efficiency of the deployment device and/or method. There are several existing methods and devices that may be considered for a deployment system. For the F111 Crew Escape Module (CEM), the recovery parachute system deployment is initiated by the firing of a catapult that ejects the complete system from the CEM. At first motion of the pack, a drogue gun is fired, which deploys the pilot parachute system. The pilot parachute system then deploys the main parachute system, which consists of a cluster of three 49-ft diameter parachutes. The pilot parachute system which extracts the F111 Crew Escape Module recovery parachute system must provide reasonable bag strip velocities throughout the flight envelope (10 psf to 300 psf). The pilot parachute system must, therefore, have sufficient drag area at the lower dynamic pressures and a reduced drag area at the high end of the flight envelope. The final design that was developed was a dual parachute system which consists of a 5-ft diameter guide surface parachute tethered inside a 10-ft diameter flat circular parachute. The high drag area is sustained at the low dynamic pressures by keeping both parachutes intact. The drag area is reduced at the higher extreme by allowing the 10-ft parachute attachment to fail. The discussions to follow describe in detail how the system was developed. 4 refs., 10 figs., 2 tabs.
Date: January 1, 1991
Creator: Tadios, E.L.
Partner: UNT Libraries Government Documents Department

Analysis of frit by sodium peroxide fusion and flow injection analysis

Description: Test runs for the immobilization of radioactive wastes in glass are now underway at the TNX Facility of the Savannah River Site. The wastes are immobilized by the Integrated Defense Waste Processing Facility Melter System (IDMS) process. The IDMS makes a borosilicate glass. To make the glass, certain quantities of boron and silicate must be maintained in the melter. The silicate is added to the melter in a substance called frit. To determine the amount of frit to add, it is necessary to calculate the percent silicate in the frit. The present method of determining the silicate content of frit has yielded inconsistent results. The focus of this project was to develop and implement a new process for determining the silicate content of frit. The author chose to achieve this goal using a colormetric method.
Date: January 1, 1990
Creator: Walker, N. & Whitaker, M.
Partner: UNT Libraries Government Documents Department

Gamma-ray and neutron leakage spectra calculated for unshieled reactors

Description: The spectra of neutrons and gamma rays escaping from unshielded reactors have been calculated for a number of simplified cases. Such spectra are important in connection with reactors operating in space orbit around the earth, which would normally have little or no heavy shielding. Reactors in space, such as the Soviet RORSAT spacecraft. Knowledge of the characteristics of their leakage spectra may be useful in understanding or minimizing such interference. The Monte Carlo Neutron-Photon (MCNP) code developed at Los Alamos has been used in these calculations. In the cases considered here the critical assembly is assumed to have spherically symmetrical geometry, with a central core of fissionable material surrounded by one or more shells of other material. The outer shells considered include beryllium, beryllium oxide, sodium, potassium, lithium, lithium hydride, and iron. The results obtained, presented as graphs, show that a number of materials that may be used in space reactors should lead to distinctive gamma-ray and neutron leakage spectra. Measurements of such spectra might well be useful in characterizing an unknown reactor type. 16 refs., 33 figs.
Date: May 1, 1990
Creator: Terrell, J.
Partner: UNT Libraries Government Documents Department

Criticality experiments with neutron flux traps containing voids

Description: A research program was initiated for the US Department of Energy (DOE) by the Sandia National Laboratory Transportation Systems Development Department in 1982 to provide benchmark type experimental criticality data in support of the design and safe operations of nuclear fuel transportation systems. The overall objective of the program is to identify and provide the experimental data needed to form a consistent, firm, and complete data base for verifying calculational models used in the criticality analyses of nuclear transport and related systems. 2 refs., 6 figs., 7 tabs.
Date: April 1, 1990
Creator: Bierman, S.R.
Partner: UNT Libraries Government Documents Department

Twinning, texture and constitutive relations for explosively formed jets

Description: We have used crystallographic-texture calculations to simulate the evolution of preferred grain orientations, and the corresponding changes in anisotropic plasticity, during explosively-driven liner collapse in metallic shaped-charge jets. For hcp metals, twinning tends to be an important deformation mechanism, and twinning is known to be strongly influenced by shocks. We consider cases of enhanced and inhibited twinning for titanium and titanium-alloys; the consequences of these treatments for the evolution of plasticity in early jet formation are discussed. 10 refs., 3 figs., 1 tab.
Date: January 1, 1989
Creator: Schiferl, S.K.
Partner: UNT Libraries Government Documents Department

A study of chromium carbide precipitation at interphase boundaries in stainless steel welds

Description: Sensitization is a deleterious process which can occur in stainless steels. It is caused by grain boundary or phase boundary precipitation of chromium carbides and the resulting formation of a chromium depleted zone adjacent to these boundaries. The carbides in question actually have the composition (Cr,Fe){sub 23}C{sub 6} (usually written M{sub 23}C{sub 6}), and precipitate in the temperature range 450--900{degree}C. Since a minimum chromium content is required to maintain the passive film necessary for resistance to electrochemical attack, the result of chromium depletion is that the steel becomes sensitized'' to possible intergranular corrosion. Sensitization often occurs as a result of welding operations. The material close to the fusion line reaches temperatures within the sensitization range. This region is called the heat affected zone (HAZ). Since many welds are multi-pass welds, the actual weld bead of one pass may lie in the heat affected zone of the next pass. The weld bead of the first pass might therefore be sensitized. Furthermore there are applications where welds will be exposed to sensitizing temperatures for very long periods of time, such as welded labels on retrievable nuclear waste containers. For these reasons the sensitization behavior of the actual weld-bead microstructures must be understood. It has been known for many years that duplex stainless steels (steels with both ferrite and austenite phases present at room temperature) have superior resistance to intergranular corrosion. A model has been proposed to explain the sensitization behavior of these alloys. This work will be concerned with testing the validity of aspects of this model using transmission electron microscopy and further understanding of the sensitization process in duplex stainless steel welds. 52 refs., 23 figs.
Date: April 1, 1990
Creator: Willis, C.F.
Partner: UNT Libraries Government Documents Department

LLE (Laboratory for Laser Energetics) review

Description: This volume of the LLE Review, covering the period July--September 1990, contains articles in two main sections: the OMEGA Upgrade and Advanced Technology Developments. The first article in Section 1 describes the changes in the overall system design of the 60-beam OMEGA Upgrade since the release of the OMEGA Upgrade Preliminary Design Document in October 1989. It is followed by an article that presents results of an investigation into stimulated rotational Raman scattering as it relates to the propagation of high-fluence ultraviolet laser beams in the OMEGA Upgrade. The third article is a report on the energy-transport measurements made on the multisegmented amplifier (MSA), built as a prototype amplifier for the original OMEGA Upgrade system configuration. The final article in Section 1 describes the design of the 20-cm-clear-aperture, single-segmented amplifier (SSA), which will be the final amplifier in the current OMEGA Upgrade system configuration. Section 2 presents the results to date of an intensive in-house effort at LLE to develop the various optical coatings required for the OMEGA Upgrade.
Date: January 1, 1990
Creator: Kumpan, S.A. (ed.)
Partner: UNT Libraries Government Documents Department

300 Area process trench sediment analysis report

Description: This report describes the results of a sampling program for the sediments underlying the Process Trenches serving the 300 Area on the Hanford reservation. These Process Trenches were the subject of a Closure Plan submitted to the Washington State Department of Ecology and to the US Environmental Protection Agency in lieu of a Part B permit application on November 8, 1985. The closure plan described a proposed sampling plan for the underlying sediments and potential remedial actions to be determined by the sample analyses results. The results and proposed remedial action plan are presented and discussed in this report. 50 refs., 6 figs., 8 tabs.
Date: December 1, 1987
Creator: Zimmerman, M.G. & Kossik, C.D.
Partner: UNT Libraries Government Documents Department

Writing parallel, discrete-event simulations in ModSim: Insight and experience

Description: The Time Warp Operating System (TWOS) has been the focus of much research in parallel simulation. A new language, called ModSim, has been developed for use in conjunction with TWOS. The coupling of ModSim and TWOS provides a tool to construct large, complex simulation models that will run on several parallel and distributed computer systems. As part of the Griffin Project'' underway here at Los Alamos National Laboratory, there is strong interest in assessing the coupling of ModSim and TWOS from an application-oriented perspective. To this end, a key component of the Eagle combat simulation has been implemented in ModSim for execution on TWOS. In this paper brief overviews of ModSim and TWOS will be presented. Finally, the compatibility of the computational models presented by the language and the operating system will be examined in light of experience gained to date. 18 refs., 4 figs.
Date: September 11, 1989
Creator: Rich, D.O. & Michelsen, R.E.
Partner: UNT Libraries Government Documents Department

Design of long induction linacs

Description: A self-consistent design strategy for induction linacs is presented which addresses the issues of brightness preservation against space charge induced emittance growth, minimization of the beam breakup instability and the suppression of beam centroid motion due to chromatic effects (corkscrew) and misaligned focusing elements. A simple steering algorithm is described that widens the effective energy bandwidth of the transport system.
Date: September 6, 1990
Creator: Caporaso, G.J. & Cole, A.G.
Partner: UNT Libraries Government Documents Department

Application of linear magnetic loss model of ferrite to induction cavity simulation

Description: A linear, frequency independent model of the rf properties of unbiased, soft ferrite has been implemented in finite-difference, time-domain, electromagnetic simulation code AMOS for the purposes of studying linac induction cavities. The simple model consists of adding a magnetic conductivity term ({sigma}{sub m}H) to Faraday's Law. The value of {sigma}{sub m} that is appropriate for a given ferrite at a particular frequency is obtained via an rf reflection experiment on a very thin ferrite toroid in a shorted coaxial line. It was found that in the frequency range 100 to 1000 MHz, the required value of {sigma}{sub m} varies only slightly (<10%), and so we approximated it as a frequency independent parameter in AMOS. A description of the experimental setup and the technique used to extract the complex {mu} from the measurements is described. The model has been used to study the impedances of the DARHT induction cavity, and comparisons between these experimental measurements and AMOS calculations is presented. Implementation of a frequency dependent version of this model in AMOS is being pursued, and a discussion of this effort is given.
Date: September 5, 1990
Creator: DeFord, J.F. & Kamin, G.
Partner: UNT Libraries Government Documents Department

Texture-induced anisotropy and high-strain rate deformation in metals

Description: We have used crystallographic texture calculations to model anisotropic yielding behavior for polycrystalline materials with strong preferred orientations and strong plastic anisotropy. Fitted yield surfaces were incorporated into an explicit Lagrangian finite-element code. We consider different anisotropic orientations, as well as different yield-surface forms, for Taylor cylinder impacts of hcp metals such as titanium and zirconium. Some deformed shapes are intrinsic to anisotropic response. Also, yield surface curvature, as distinct from strength anisotropy, has a strong influence on plastic flow. 13 refs., 5 figs.
Date: January 1, 1990
Creator: Schiferl, S.K. & Maudlin, P.J.
Partner: UNT Libraries Government Documents Department

The Sandia Transportable Triggered Lightning Instrumentation Facility

Description: Development of the Sandia Transportable Triggered Lightning Instrumentation Facility (SATTLIF) was motivated by a requirement for the in situ testing of munitions storage bunker. Transfer functions relating the incident flash currents to voltages, currents, and electromagnetic field values throughout the structure will be obtained for use in refining and validating a lightning response computer model of this type of structure. A preliminary shakedown trial of the facility under actual operational conditions was performed during the summer of 1990 at the Kennedy Space Center's (KSC) rocket-triggered lightning test site in Florida. A description is given of the SATTLIF, which is readily transportable on a single flatbed truck or by aircraft, and its instrumentation for measuring incident lightning channel currents and the responses of systems under test. Measurements of return-stroke current peaks obtained with the SATLLIF are presented. Agreement with data acquired on the same flashes with existing KSC instrumentation is, on average, to within {approximately}7 percent. Continuing currents were measured with a resolution of {approximately}2.5 A. This field trial demonstrated the practicality of using a transportable triggered lightning facility for specialized test applications. 5 refs., 12 figs., 1 tab.
Date: January 1, 1991
Creator: Schnetzer, G.H. & Fisher, R.J.
Partner: UNT Libraries Government Documents Department

Damage to metallic samples produced by measured lightning currents

Description: A total of 10 samples disks of 2024-T3 aluminum and 4130 ferrous steel were exposed to rocket-triggered lightning currents at the Kennedy Space Center test site in Florida during the summer of 1990. The experimental configuration was arranged so that the samples were not exposed to the preliminary streamer, wire-burn, or following currents that are associated with an upward-initiated rocket-triggered flash but which are a typical of naturally initiated lightning. Return-stroke currents and continuing currents actually attaching to the sample were measured, augmented by close-up video recordings of approximately 3 feet of the channel above the sample and by 16-mm movies with 5-ms resolution. From these data it was possible to correlate individual damage spots with streamer, return-stroke, and continuing currents that produced them. Substantial penetration of 80-mil aluminum was produced by a continuing current of submedian amplitude and duration, and full penetration of a 35-mil steel sample occurred under an eightieth percentile continuing current. The primary purpose of the data acquired in these experiments is for use in improving and quantifying the fidelity of laboratory simulations of lighting burnthrough. 9 refs., 8 figs.
Date: January 1, 1991
Creator: Fisher, R.J. & Schnetzer, G.H.
Partner: UNT Libraries Government Documents Department

Total-dose radiation hardness assurance for space electronics

Description: An improved standard total-dose test method is described to qualify electronics for a low-dose radiation environment typical of space systems. The method consists of {sup 60}Co irradiation at a dose rate of 1--3 Gy(Si)/s (100--300 rad(Si)/s) and a subsequent 373 K (100{degree}C) bake. New initiatives in radiation hardness assurance are also briefly discussed, including the Qualified Manufacturers List (QML) test methodology and the possible use of 1/f noise measurements as a nondestructive screen for oxide-trap charge related failure. 8 refs.
Date: January 1, 1990
Creator: Winokur, P.S. & Fleetwood, D.M.
Partner: UNT Libraries Government Documents Department

Theory of harmonic radiation using a single-electron source model

Description: Significant progress has recently been made toward the understanding of the various mechanisms that generate harmonic radiation in plane-polarized free electron lasers. Within the context of a single-frequency coherent-spontaneous emission model, a distributed transverse source function for a single electron has been derived. This source is multiply peaked, with the number of peaks being equal to the harmonic number. The peaks and nulls in the radiation source are analogous to the radiation peaks seen in the spontaneous radiation pattern of a single electron. When the distributed source function is averaged over transverse space, the simplified one-dimensional results are recovered. The distributed source function model predicts the generation of even harmonic radiation with odd-symmetry in the electron wiggle plane (for electrons traveling along the wiggler axis) and odd harmonic radiation patterns with even transverse symmetry. A method for modeling the multi-pole nature of the harmonic radiation on a discrete grid is described. When the transverse electron beam distribution is slowly varying, all the harmonics can be adequately modeled with multi-poles having only a few peaks. This model has been incorporated into the 3-D FEL simulation code FELEX. Simulations of the Los Alamos and Stanford FEL oscillators have been performed. How the harmonic transverse spatial electric field profiles change for different operating conditions is examined. 11 refs., 5 figs.
Date: January 1, 1989
Creator: Schmitt, M.J. & Elliott, C.J.
Partner: UNT Libraries Government Documents Department

Cumulative beam breakup in radio-frequency linacs

Description: An analytic model of cumulative beam breakup has been developed which is applicable to both low-velocity ion and high-energy electron linear accelerators. The model includes arbitrary velocity, acceleration, focusing, initial conditions, beam-cavity resonances, and variable cavity geometry and spacing along the accelerator. The model involves a continuum approximation'' in which the transverse kicks in momentum imparted by the cavities are smoothed over the length of the linac. The resulting equation of transverse motion is solved via the WKBJ method. Specific examples are discussed which correspond to limiting cases of the solution. 16 refs.
Date: January 1, 1990
Creator: Bohn, C.L. & Delayen, J.R.
Partner: UNT Libraries Government Documents Department