Publications

As part of the Strategic Petroleum Reserve (SPR), the Weeks Island oil storage site is a converted salt mine that contains approximately 73 million barrels of oil overlying 0.5 million barrels of brine. The oil is contained on two levels of the converted mine which are connected by a number of shafts and openings. Oil recycle exercises are periodically conducted to test the oil fill and withdrawal systems in which oil is simultaneously injected and withdrawn from two different locations in the lower level, and brine may be transported around the lower level of the mine by the movement of the oil. 11 refs., 16 figs.

An expert system developed to provide assistance to those involved with the creation, modification, interpretation and maintenance of Sandia's Engineering Procedures is described. 6 refs., 2 figs.

The Engineering Graphics System (EGS) is a computer program for use on Digital Equipment Corporation VAXstation color workstations. Its purpose is to manage and plot sets of engineering analysis data for use in reports and presentations. It is capable of producing nearly any type of x-y plot from a set of tabulated data. After the plot curves have been retrieved from the tabulated data, EGS can be used to interactively modify the appearance of the plot for use in a report or presentation. Modifications appear on the workstation display exactly as they appear on final hardcopy, which avoids costly iterations. Hardcopy plots can be made on two different black and white laser printers and on two different color printers, and plots can be converted for use by the Interleaf technical publishing software. 222 figs.

Power deposition measurements have been carried out on the ALT-II toroidal belt pump limiter and the inner bumper limiter in TEXTOR for Ohmic, neutral beam and RF heated discharges. Two infrared cameras and the ALT-II thermocouple array indicate that {lambda}{sub E} remains unchanged (7 mm) in the presence of beams but increases to 10 mm with ICRH. The heating distribution is less uniform on the bumper limiter than on ALT-II, which potentially could explain the differences seen in graphite surface pumping. 9 refs., 3 figs., 1 tab.

The operation of TORE SUPRA at full power (25MW, 30s) has led to the design of a full set of actively pumped carbon limiters to remove at least 8MW and to partially control the particle balance. An interim version is now installed, composed of 5 vertical and one horizontal outboard (OPL) pump limiters, semi-inertially water cooled. The latter is a result of a collaboration between the US DOE and the Association EUR-CEA, it is fully instrumented and therefore can serve as a reference for the final design. Ohmic discharges (1.85T, 740kA, 8.5s) in helium have been used to test the thermal load on and the particle exhaust efficiency of the OPL. In these experiments the plasma is formed on the inner wall (R = 232 cm, a = 76 cm) and subsequently displaced (6 cm) outward, early on the current plateau, to lean on the OPL (R = 238 cm, a = 75 cm). In addition to the limiters above, a non-pumped outboard (ONLP) limiter of identical shape to the OPL served to produce similar discharges for better comparison and determination of particle control. A comparison is made hereafter of the thermal load and particle pumping effects on the OPL when the plasma is in contact either with the OPL/ONPL alone or with the OPL and the vertical limiters together. 3 refs., 1 fig., 2 tabs.

Particle collection, removal, and exhaust by the toroidal belt pump limiter ALT-III have been measured in deuterium discharges with co-, counter-, and balanced injection of 48 keV neutral hydrogen particles. Particle collection increases from 50-80 A to 150-320 A during 1.2 MW of co- or counter-injection or 2.4 MW of balanced injection. The removal rate for pumping at two of the eight blades (3 of 15 scoops) reaches 2.7 Torr-l/s with a removal efficiency of nearly 45%. Extrapolating these results to a full belt with 15 scoops and eight pumps yields 140 amps of removal. This compares favorably with the maximum injectable current of 50 A and suggests that ALT-II with full pumping can provide sufficient exhaust during NI heating. 4 figs.

The microstructure and mechanical properties of high purity aluminum implanted with 20 at. % oxygen to a depth of roughly 500 nm and subjected to various thermal histories have been examined. Transmission electron microscopy and Rutherford-backscattering spectrometry were used to characterize the depth and nature of the implanted zone. As implanted, the material appears to contain a homogeneous distribution of disordered precipitates with sizes of 1.5-3.5 nm. Annealing at 450 or 550{degree}C/1 hr induces ordering of the precipitates but only causes slight coarsening. Ultra-low load identation hardness testing was used to probe the mechanical response of the surface-modified material. The data from the hardness tests were interpreted through the use of a finite-element model; the results indicate the flow stresses of an implanted and annealed layer are as high as 1600 MPa. The as-implanted material is much harder, approaching 3300 MPa. The degree of strengthening expected for the as-implanted and post-annealed material on the basis of the observed microstructure was estimated using several micromechanical models, and the results conform to the findings from indentation testing. 9 refs., 5 figs.

It has been observed on TEXTOR that in low density discharges the electrons gain enough energy to emit relativistic synchrotron radiation in the 3--6 {mu}m IR-range, and this radiation is due to electrons with energies up to 30 MeV. The momentum in perpendicular direction amounts to about 1/10 of the longitudinal one. The total number of runaways is of the order of 10{sup 16} electrons, and they carry a current of about 20% of the total plasma current. 3 refs., 1 fig.

The surface properties of symmetric microphase separated diblock copolymers of polystyrene (PS) and polymethylmethacrylate (PMMA) were investigated using X-ray photoelectron spectroscopy (XPS), the specular reflectivity of neutrons and secondary ion mass spectrometry (SIMS). PS, the lower surface energy component, exhibited a preferential affinity for the free surface. For copolymers that are far from the bulk microphase separation transition (MST), the surface consists of a layer of pure PS. When the system is close to the MST the surface is a mixture of PS and PMMA. The PS surface excess can be described by a N-{sup 1/2} dependence, where N is the number if segments that comprise the copolymer chain. It is shown that the surface undergoes an ordering transition at a temperature T{sub s} that is above that of the bulk MST. The ordering of the bulk lamellar morphology is induced by an ordering at the surface. This is analogous to the ferromagnetic order observed in systems such as Gd at temperatures above the bulk Curie temperature. The results here are discussed in light of previous work on copolymer surfaces and in light of mean field theory. 31 refs., 8 figs.

Oxygen ion beam bombardment has been studied as a means for incorporating oxygen into thin films of Y-Ba-Cu-oxide either by enhancing the transport of oxygen to substrates during ion-beam sputtering, or by direct incorporation of oxygen by ion-assisted deposition. Optical emission spectroscopy was used to study the ion-beam bombardment of bulk superconducting targets as the oxygen content of the ion beam was varied between 0% (pure argon) and 100% oxygen. This showed that oxygen did not directly combine with metallic elements in the target to increase the oxygen content of the stream of particles moving toward the substrate. The oxygen content of the sputter beam did, however, change the relative emission intensity from the various target components. Addition of a second ion beam directing an oxygen beam toward the substrate as the film is grown, caused large variations in the stoichiometry of the deposited films. At low ion currents, no increase in the oxygen content of the films was detected, while at relatively high currents, the oxygen incorporation increased. However, the sputtering of the metallic components of the film increased, leading to very low growth rates. 8 refs., 5 figs.

Intense beams of light ions are being developed at Sandia National Laboratories as a promising driver option for Inertial Confinement Fusion (ICF) implosions. The Particle Beam Fusion Accelerator II (PBFA II) will provide the physics basis for light-ion-beam driven ICF targets. Recent progress made in ion beam generation focusing on PBFA II has led to a record 5.4 TW/cm{sup 2} peak focal intensity with {gt}80 kJ proton energy delivered to a 6-mm diameter sphere. The driver-development program on PBFA II is reviewed. A design concept for a light ion beam driver for the Laboratory Microfusion Facility is also presented. 34 refs., 9 figs., 1 tab.

In an earlier paper, we reported that it is possible to train a first-order multi-layer feedforward network with backpropagation to classify raw 8-bit images of vehicles. We concluded that a linear feedforward network is capable of within-class generalization when trained with perspective views taken every 10{degree}, but it is incapable of one-class generalization. This paper describes the results of a set of experiments to train a feedforward network with second-order inputs to perform one-class classification on image data. We compare the results of the first-order network and the second-order network and show that the second order network is better able to generalize as a one-class classifier. 7 refs., 6 figs.

Short communication.

Ion beam studies on radiation enhanced sublimation (RES) have shown that above 800{degree} C energetic ions incident on graphite produce erosion in the form of carbon atoms with thermal energies and that the erosion rate rises roughly exponentially with temperature. Until recently, the question remained whether RES would scale linearly with flux over three to four orders of magnitude to the plasma edge fluxes in CIT and ITER, where the predicted erosion rates would severely limit the designs for plasma-facing components. Also, RES and carbon self-sputtering may also be involved in the carbon blooms'' observed in TFTR and JET. The data reported here from PISCES, a plasma source at UCLA, are the first RES data at fluxes approaching the plasma edge conditions in a large tokamak and they show little reduction from a direct linear dependence upon flux. Erosion rates measured by weight loss are reported for POCO graphite exposed to helium plasmas for a temperature range from 900--2000{degree} C, ion energies of 30--300 eV, ion fluxes of 1--6 {times} 10{sup 18} cm{sup {minus}2} s{sup {minus}1}, densities of 2--10 {times} 10{sup 12} cm{sup {minus}3} and electron temperatures of 4-10 eV. For these conditions, the amount of redeposition and carbon self-sputtering was minimal. Over 1700{degree} C, there is evidence of electron emission from the sample. 26 refs., 4 figs., 1 tabs.

Silicon power diodes, transistors, thyristors and other devices can be damaged by elevated temperatures, temperature cycling, and radiation. In this paper we discuss the vulnerability of devices that integrate bipolar and MOSFET (metal-oxide-semiconductor-field-effect transistor) devices onto a single chip. Such devices offer the advantages of good current carrying capability that is characteristic of bipolar structures and high impedance control nodes that are characteristic of MOSFET devices. Devices located near a space-based fission power source will be subjected to high temperatures, temperature cycling, naturally occurring radiation, radiation from the reactor; and these devices may be subjected to radiation from or caused by weapons used to attack the power source. Damaging radiation includes electrons and protons trapped in naturally occurring radiation belts, electrons pumped into these belts as a result of nuclear explosions, cosmic rays, neutrons from the reactor, and high energy photons (gamma rays and x-rays). 3 refs., 2 figs.

We consider problems related to the computation of Hermite and Smith normal forms of integer matrices, and more generally matrices over a principal ideal ring. First, we show that if the matrix A is m {times} n, with rank m and integer entries bounded in absolute value by T, then the Hermite normal form can be computed in O(m{sup 2}nB(m log(mT))) bit operations, where B(t) denotes a function that bounds the time required to perform the extended Euclidean algorithm on two t bit integers. Furthermore we show that the Smith normal form can be computed in O(m{sup 3}nB(m log(mT))log(mT)) bit operations. In the second part of the paper we apply fast matrix multiplication techniques to the problem of triangularizing a matrix over a ring using elementary column operations. We also prove that matrix inversion and multiplication are equivalent in complexity over an arbitrary Principal Ideal Domain, generalizing a result of Bunch and Hopcroft. We then apply our general results to obtain an algorithm for triangularizing integer matrices that has a faster running timer than the known Hermite normal form algorithms. The triangular matrix that is computed has small entries like the Hermite normal form, and will suffice for many applications. In the last part of the paper, we discuss a probabilistic method for calculating Smith normal forms. 17 refs.

We have examined several crystals belonging to the Tl-2122 structure type (Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub 8} with c = 29{angstrom}), and have shown that cation solid solution occurs. Such cation disorder appears to be responsible for the observed small differences in lattice parameters reported by various investigators and to contribute towards the substantial variation in the superconducting transition temperatures. 10 refs., 2 tabs.

Nuclear power plants present the fire protection community with unique challenges. In addition to the traditional concerns of life safety and property loss prevention, nuclear safety analysts must also be concerned with the impact of fires on the safe operability of the nuclear reactor. Safe shutdown equipment must be protected from fire damage. When nuclear power plants were first designed and built, fire safety considerations were based primarily on the same criteria applied to general industrial facilities, primarily those concerning life safety and property loss prevention. This practice continued until 1975 when the Brown's Ferry nuclear reactor site experienced a severe cable tray fire. The fire burned for over seven hours, due in part to the reluctance of on-site personnel to use water on the fire for fear of shorting out critical electrical circuits. 4 figs.

The radiation spectrum constituents of interest to microelectronics are prompt gamma or x-ray, total dose, neutrons (or protons), and cosmic radiation. Each of these constituents has a unique effect upon microelectronic components and requires unique techniques to improve the microelectronic radiation tolerance to such an exposure. This paper reviews the radiation effects associated with the natural space and nuclear reactor radiation environment, that is to say, total dose, neutrons, and cosmic rays. 2 refs., 6 figs.

Shock-induced reaction synthesis (SRS) is used for solid state processing of Ni-Al, Ni-Si, and Nb-Si type compounds, starting with elemental powder mixtures. The constituent elemental powders are blended in different stoichiometries and packed at 65% density in stainless steel capsules. A steel flyer plate, accelerated by the detonation of an explosive, impacts the powder containing capsules embedded in a steel recovery fixture backed by a momentum trap. The shock wave generated upon impact triggers a self-sustaining, exothermic reaction between the elemental powder constituents, thereby synthesizing the compound and at the same time consolidating the porous mass into 12mm diameter by 5mm thick compacts. The characteristics of the SRS technique and the structural features of the shock synthesized products will be discussed. 18 refs., 11 figs.

Preliminary BUCKSHOT simulations of a recirculating linear accelerator have been made. Two accelerator configurations have been examined for a variety of beam currents (10-40 kA). The first configuration is an attempt to simulate conditions accessible to near-term experiments. The second configuration tries to mock up a next generation application type machine. 3 figs.

Hypervelocity launchers are used to study the high-pressure equation of state of materials in regimes inaccessible by other methods. Two-stage light gas guns have been extremely useful for these applications, but have a practical velocity limit of about 8--9 km/s for impact studies. In this paper, we describe a three-stage launcher consisting of a two-stage light gas gun combined with a third-stage railgun, which overcomes previous velocity limitations pertaining to two-stage guns. This launcher is being developed for operation to 15 km/s and has achieved projectile velocities of 7.2 km/s to date. 10 refs., 9 figs., 1 tab.

The in-plane linear elastic constants of woven fabric are determined in terms of the specific fabric microstructure. The fabric is assumed to be a spatially periodic interlaced network of orthogonal yarns and the individual yarns are modeled as extensible elastica. These results indicate that a significant coupling of bending and stretching effects occurs during deformation. Results of this theoretical analysis compare favorable with measured in-plane elastic constants for Vincel yarn fabrics. 17 refs., 2 figs., 1 tab.

The utility of the magnetically insulated transmission line oscillator (MILO) as a high power microwave source depends on how efficiently power can be extracted from it. We have designed a slow-wave stepped transformer for the purpose of axially extracting microwave power from a 3.6 GHz coaxial MILO. The slow-wave transformer design was optimized using particle-in-cell simulation, and tested in experiments performed on the HPM Simulation Division's GEMINI and GYPSY water Blumlein pulse power sources. In this paper we summarize the slow-wave stepped transformer design, and describe MILO axial power extraction experiments which yielded up to 300 MW of radiated power. 10 refs., 4 figs., 2 tabs.

This presentation is a case study of the system that was developed to move data between our mainframe HRIS and the REGISTRAR. It not only contains a description of the system itself but of the factors that come into play in deciding whether to implement a system at all and in deciding what kind of system to implement.

Heavy particle radiation can produce upsets in digital circuits as well as trigger burn out or breakdown in power MOSFETs and MNOS nonvolatile memories. Latch-up may also be stimulated by heavy ions. This report covers work done on the effects of heavy particle radiation on PN junctions, CMOS inverters, CMOS latch, MOSFET and non-volatile memories. 15 refs., 3 figs.

In this study, we explored several ways of extending SP-100 reactor technology to higher power levels. One approach was to use the reference SP-100 pin design and increase the fuel pin length and the number of fuel pins as needed to provide higher capability. The impact on scaling of a modified and advanced SP-100 reactor technology was also explored. Finally, the effect of using alternative power conversion subsystems, with SP-100 reactor technology was investigated. One of the principal concerns for any space-based system is mass; consequently, this study focused on estimating reactor, shield, and total system mass. The RSMASS code (Marshall 1986) was used to estimate reactor and shield mass. Simple algorithms developed at NASA Lewis Research Center were used to estimate the balance of system mass. Power ranges from 100 kWe to 10 MWe were explored assuming both one year and seven years of operation. Thermoelectric, Stirling, Rankine, and Brayton power conversion systems were investigated. The impact on safety, reliability, and other system attributes, caused by extending the technology to higher power levels, was also investigated. 6 refs., 4 figs., 3 tabs.

Outlier samples can have very detrimental effects on the performances of multivariate calibration methods, as these methods are generally not very robust. Often, the software implementations of these methods do not check for outliers. If outliers are not detected, invalid predictions may result. This paper illustrates some simple exploratory procedures for detecting outliers with examples from near-infrared and mid-infrared spectroscopy using partial least-squares regression as the calibration method. 8 refs., 9 figs., 1 tab.

The experiments described here indicate when one of Nature's best fractals -- the Brownian trail -- becomes nonfractal. In most ambient fluids, the trail of a Brownian particle is self-similar over many decades of length. For example, the trail of a submicron particle suspended in an ordinary liquid, recorded at equal time intervals, exhibits apparently discontinuous changes in velocity from macroscopic lengths down to molecular lengths: the trail is a random walk with no velocity memory'' from one step to the next. In ideal Brownian motion, the kinks in the trail persist to infinitesimal time intervals, i.e., it is a curve without tangents. Even in real Brownian motion in a liquid, the time interval must be shortened to {approximately}10{sup {minus}8}s before the velocity appears continuous. In sufficiently rarefied environments, this time resolution at which a Brownian trail is rectified from a curve without tangents to a smoothly varying trajectory is greatly lengthened, making it possible to study the kinetic regime by dynamic light scattering. Our recent experiments with particles in a plasma have demonstrated this capability. In this regime, the particle velocity persists over a finite step length'' allowing an analogy to an ideal gas with Maxwell-Boltzmann velocities; the particle mass could be obtained from equipartition. The crossover from ballistic flight to hydrodynamic diffusion was also seen. 8 refs., 1 fig.

The MELCOR computer code, which has been developed at Sandia National Laboratories for the US Nuclear Regulatory Commission as a tool for calculating realistic estimates of severe accident consequences and source terms, has been used to analyze a series of containment issues for station blackout sequences for the Grand Gulf Nuclear Power Plant. The results indicate that there is a limited time interval in which the drywell atmosphere would be flammable, and that this would only occur if the vacuum breaker were to stick open within a narrow time window. If burning does occur during this time, it appears quite likely that it would not pose a threat to the drywell wall. The main conclusion from this study is that the drywell atmosphere is not very likely to be flammable for a station blackout sequence. 1 ref. (S.J.)

The influence of postweld heat treatment (PWHT) on the structure, mechanical properties and fracture characteristics of pulsed, Nd: YAG laser welds in a Ti-14.8 wt % Al-21.3 wt % Nb titanium aluminide has been investigated. Significant microstructure variations within the fusion zone (FZ) of all heat-treated welds were attributed primarily to the influence of local compositional fluctuations on decomposition of the metastable-{beta} microstructure present in the as-welded FZ. An increase in PWHT temperature promoted a decrease in the maximum FZ hardness and an increase in the longitudinal-weld bend ductility. Correspondingly, the proportion of ductile tearing to cleavage fracture within the FZ increased with an increase in PWHT temperature. 8 refs., 6 figs.

A matched chirp transform (MCT) method for detecting a dispersive electromagnetic pulse is described. The unique feature of this transform is that it gives a distribution of signal amplitude over time rather than frequency, thereby simplifying signal detection and identification in the case described here. In the MCT method, the incoming signal is matched to a set of signal segments that chirp in accordance with an expected model of the dispersive medium. The performance of the MCT method is compared to that of a standard periodogram method of frequency measurement.

In previous RADLAC-II beam propagation experiments, stable propagation over a Nordsieck length, in full pressure Albuquerque air (p {approximately}640 Torr) was observed. In these experiments, high transverse momentum resulted in a large equilibrium radius and thus a long betatron wavelength. Following the completion of the RADLAC-II upgrade, a new set of experiments with a small diameter (d {approximately}2 cm), high current (I {approximately}40 kA), low transverse momentum ({beta}{perpendicular} {approximately}0.2) should be possible. The development of time-resolved diagnostics, data analysis codes, and the formulation of output from theoretical calculations in a format as seen by these diagnostics in the lab continues to be a major source of effort in the program. 2 figs.

The final link in the High-Power Microwave (HPM) coupling chain is the distribution of energy on printed-circuit (pc) boards. This distribution is a critical part of the total problem, because the bottom line for damage or upset is what occurs at the component level. Like ports-of-entry (POE's), board coupling paths have their own transfer functions. Since most pc boards are not designed to operate at microwave frequencies, these transfer functions can be very complicated. In addition, active elements on the board are likely to make this part of the problem non-linear. 3 refs., 5 figs.

This paper reports the changes caused by fast neutrons and 200 MeV protons in the electrical properties of high electron mobility transistors (HEMT). A larger gate voltage was required after irradiation with neutron fluences in the 1E14 to 2E15 n/cm{sup 2} range and 200 MeV proton fluences in the 1E14 to 1E15 p/cm{sup 2} range than was required prior to irradiation to obtain the same value of I{sub ds}. The increase in gate voltage required to compensate for a fluence of 1E15 protons/cm{sup 2} was up to four times as great as that required to compensate for the same fluence of neutrons. All devices showed microwave gain (s21) after exposure to 6E14 particles/cm{sup 2} if the gate bias was adjusted to maintain the pre-irradiation value of I{sub ds}. Gamma irradiation at 5E7 rads(GaAs) had no detectable effect on the devices. 8 refs., 6 figs., 1 tab.

Concerns about low-{gamma} relativistic electron beams (REB) being initially injected into the RLA and about energy spreads due to degradation of the accelerating cavity repeating pulse shapes have resulted in our designing a new 4-MV, 20-kA injector, improving the 24-switch trigger system for the ET-2 cavity, and identifying critical factors in the cavity design that affect the pulse shape. We summarize the Metglas inductively isolated, stacked cavity injector design and report on the improvements (completed and proposed) for the ET-2 cavity pulsed power. 7 refs., 6 figs.

Three prototype zinc/bromine batteries were evaluated a Sandia during the last year. The objectives of these tests were to determine performance, cycle life, durability of the auxiliary components, and failure mechanisms. All three were deliverables from a Sandia development contract with Energy Research Corporation (ERC). The test results were communicated to ERC along with suggestions for improving battery design and reliability. 3 figs., 2 tabs.

Zinc/bromine flow batteries are being developed for vehicular and utility load leveling applications by Johnson Controls Co. and Energy Research Corp. under DOE sponsorship. Problems that have been encountered with the zinc/bromine battery are loss of coulombic efficiency brought about by permeation of bromine through the separator and limited life caused by attack of the bromine-containing electrolyte on plastic parts, particularly the flow frame. In this paper, we show that large decreases in the bromine transport rates through microporous separators can be achieved with only a minimal loss of conductivity and identify a chemically stable replacement for PVC, a flowframe material. 4 figs., 1 tab.

The working group on electrical breakdown in vacuum was charged with considering all possible mechanisms by which electrical breakdown might occur either through the vacuum or along insulator bushings in large area electron beam emitter assemblies. It was understood that present systems need to be scaled up, by an order of magnitude or more in both beam area and total energy, to meet demands for higher power and larger size machines, and that increases in the e-beam current density and transport efficiency are also sought. A consideration of the consequences of such a scale-up was pertinent to many of the topics listed in the working-group agenda. Our group attempted to address each of these topics. 18 refs.

Whenever a new elastomer is formulated or an old formulation is modified, it is important to estimate the material's anticipated lifetime in various use environments. For extended lifetimes (years) this often requires the application of accelerated aging techniques which typically involve the modelling of results obtained at higher-than-ambient environmental stress levels. For many practical applications of elastomers, air is present during environmental exposures -- this usually implies that important oxidation effects underly the degradation of the material. Unfortunately, exposure of elastomers to air during aging often results in inhomogeneously oxidized samples, a complication which impacts attempts both to understand the oxidation process and to extrapolate accelerated exposures to long-term conditions. As has been clear for many years, in order to confidently extrapolate shorter-term accelerated simulations to long-term, air-aging conditions, one must be able to monitor and quantitatively understand diffusion-limited oxidation effects. In this review we will highlight some of the recent developments in both experimental techniques and theoretical modelling of relevance to this goal. 28 refs., 12 figs.

The discrete ordinates (S{sub N}) method, first developed for stellar atmospheres, has been used extensively on various other radiation transport problems. In reactor analysis the method is generally used to generate parameters for design models based on more approximate but less expensive methods (such as diffusion theory) so that the spatial-spectrum coupling is represented accurately on a microscopic reaction rate level. It has a decisive advantage over Monte Carlo methods in computing the pin and assembly power profiles. In shielding problems where the penetration of the radiation can be deep, the method is used widely in design calculations. In oil-well logging problems which also involve deep penetration and have a stringent accuracy requirement on the detector responses, the method complements the Monte Carlo techniques. Recently, the discrete ordinates method with appropriate cross sections has been used in coupled photon-electron transport problems. In this paper the basic method is briefly reviewed, its applications illustrated, its merits and pitfalls discussed, and the recent advances in the attendant numerical techniques which have enhanced the capabilities of the method are enumerated. 28 refs., 1 fig.

During severe light water reactor accidents like Three-Mile Island (TMI-2), the reactor core can suffer considerable damage. Of interest here are melt progression, oxidation and gas phase natural convection in the reactor core after the fuel rods suffer a significant loss of geometry. This study describes a two-dimensional porous medium model that considers the motion of three fields: vapor, melt, and solid. A base case solution is described and the effects of oxidation, melt relocation, and Fe-Zr interactions are discussed. 16 refs., 7 figs.

Materials Control techniques are utilized to provide assurance that nuclear materials are being handled properly. In the event that materials are improperly handled or potentially malevolent activities utilizing nuclear materials are initiated, the materials control approach should provide a real-time indication to allow a rapid mitigating response. The appropriate response can range from correcting an inadvertent error to preventing an intentional insider-perpetrated incident. This paper is directed at the use of materials control techniques to deter and detect insider malevolence. 1 fig.

A two-part polyurethane foam has been tested in the laboratory and in the field to assess its utility in controlling lost circulation encountered when drilling geothermal wells. A field test was conducted in The Geysers in January, 1988, to evaluate the chemical formulation and downhole tool used to deploy the chemicals. Although the tool apparently functioned properly in the field test, the chemicals failed to expand sufficiently downhole, instead forming a dense polymer that may be ineffective in sealing loss zones. Subsequent laboratory tests conducted under simulated downhole conditions indicate that the foam chemical undergo sever mixing with water in the wellbore, which disturbs the kinetics of the chemical reaction more than was previously contemplated. The results indicate that without significant changes in the foam chemical formulation or delivery technique, the foam system will be ineffective in lost circulation control except under very favorable conditions. 4 refs., 6 figs., 2 tabs.

Results of fixed-bed hydropyrolysis and low temperature hydrogenation tests with a selection of coals and dispersed catalysts are described. Tar yields greater than 60% have been achieved in hydropyrolysis using sulphided molybdenum (Mo) with Mo concentrations as low as 0.1% daf coal for a number of bituminous coals. The hydrogenation tests indicated that the threshold temperature with these catalysts for oil generation from bituminous coals is 350{degree}C. 16 refs., 2 figs., 2 tabs.

We have developed a fast parallel version of an existing synthetic aperture radar (SAR) simulation program, SRIM. On a 1024-processor NCUBE hypercube it runs an order of magnitude faster than on a CRAY X-MP or CRAY Y-MP processor. This speed advantage is coupled with an order of magnitude advantage in machine acquisition cost. SRIM is a somewhat large (30,000 lines of Fortran 77) program designed for uniprocessors; its restructuring for hypercube provides new lessons in the task of altering older serial programs to run well on modern parallel architectures. We describe the techniques used for parallelization, and the performance obtained. Several novel parallel approaches to problems of task distribution, and direct output were required. These techniques increase performance and appear to have general applicability for massive parallelism. We describe the hierarchy necessary to dynamically manage (i.e., load balance) a large ensemble. The ensemble is used in a heterogeneous manner, with different programs on different parts of the hypercube. The heterogeneous approach takes advantage of the independent instruction streams possible on MIMD machines. 18 refs., 7 figs., 4 tabs.

The Buckshot code is a gridless particle simulation code which is used extensively at Sandia to study relativistic electron beam propagation in the ion-focused regime. The present version of the code evaluates the force on a particle by summing over all the other particles, thus the execution time is proportional to N{sup 2} where N is the number of simulation particles. A new gridless field solver has been developed with time scaling of N log N and the breakeven point between the old and new code is around N = 64 on the Cray X-MP computer. For N = 1000, the new solver is about nine times faster than the old version. The new solver is based on a solution of the two-dimensional Poisson equation which if Fourier decomposed in the azimuthal direction and the solution of the radial equation is represented by integrals over the charge density. These integrals are then replaced by sums over the simulation particles which are assumed to be point particles. The near-field singularity is removed by the Fourier decomposition so long as the number of Fourier modes is much less than the number of simulation particles. The algorithm is written in such a way that the field due to a given species is Fourier decomposed with respect to the center of mass of that species, thus it is possible to study linear and nonlinear ion hose physics with a very small number of azimuthal modes. Typically M = 2 is found to be sufficient for most IFR problems. The old and new solvers have been compared and the agreement is excellent. 2 refs., 3 figs.

It has been shown that a constant axial magnetic field does not affect the growth rate of the ion hose instability. However, if the field is allowed to vary in time, on the ion motion time scale, it is expected that particle orbits will be affected in a way that will result in a time varying beam wavelength. This can lead to detuning of the instability. Results of the rigid model with a time varying field of strength similar to the channel strength, show a significant decrease in the growth of the instability. Also, simulations using the BUCKSHOT code confirm the small effect of a steady magnetic field on hose growth and show a significant decrease in growth with a time varying field. 3 figs.

Sandia National Laboratories (SNL) has been involved in the evaluation of the sodium/sulfur technology for several years. Until recently, the effort concentrated on the performance of single cells. Recently, the evaluation of 4-cell string was initiated. The majority of the activity during the past two years has focused on cells from Chloride Silent Power, Limited (CSPL). To date, four groups of PB cells and 4-cell strings, which consisted of PB cells, have been evaluated. The first group of ten cells delivered to Sandia were on test for approximately one year. The majority of these cells failed due to corrosion problems in the sulfur seal. However, two cells completed over 800 cycles, and one of these cells completed nearly 1600 cycles. 4 figs., 1 tab.

A high detectivity infrared photodiode was constructed using an InAs{sub 0.15}Sb{sub 0.85}/InSb strained-layer superlattice (SLS). The surface passivated device exhibited detectivities {ge} 1 {times} 10{sup 10} cm{radical}Hz/W at wavelengths {le} 10 {mu}m. This device demonstrates the feasibility of a long wavelength, photovoltaic infrared detector technology based on InAsSb SLSs. 8 refs., 4 figs.

The Borehole Directional Radar System is a high-power, high- resolution tool that is being developed to locate lithologic layers of fractures away from a wellbore. The prototype is a 50-kW peak- power pulsed directional radar system that determines fracture location by transmitting powerful radar pulses, 8 nanoseconds in length, in a known direction from a borehole. The frequency spectrum of the pulses ranges up to the VHF band, which is between 30 and 300 MHz. The transmitter and receiver rotate in place, permitting the tool to scan for fractures in all directions from the borehole. Because discontinuities in the rock interrupt and reflect radar signals, signals that return to the tool's receiving antenna indicate fractures. The distance of the fracture from the borehole is determined by the time delay of the return signal. The radio frequency signal is sampled and transmitted to the surface by wireline at audio frequencies, and then reconstructed at the surface using a personal computer. The key to the tool's potential is its ability to accurately measure distance and direction of a lithologic discontinuity underground. This paper presents field test results that show the capabilities of the tool for locating lithological discontinuities up to 10.5 m (34.5 ft) away from a wellbore. Unique features of the system are discussed. Potential applications of the system are described, such as locating gas and oil reservoirs below a salt dome and possibly detecting a blow-out well with or without casing. 10 refs., 8 figs.

An empirical scaling relationship between the mean electric field and the breakdown time has been found. Many divergent sets of data were used from breakdown experiments on power lines, laser-triggered switches, trigatrons, e-beam triggered gaps, sharp-point electrode to plane gaps, and uniform field gaps. This relationship builds on the Felsenthal and Proud data and extends their breakdown time delay (formative time) data by three orders of magnitude and into the region of interest for triggered gas switching. The data indicates that electrically triggered gaps, laser-triggered gaps, and untriggered gaps are governed by the same time-delay processes. Predictions can be made of trigger gap geometry, trigger delays, and trigger polarity effects. Breakdown delays of sub-centimeter-long to at least 8-meter-long gaps in air with either high or low field-enhanced electrodes are described by this equation. In addition, this relationship appears to be valid for a variety of gases and even accurately predicts the breakdown delay of mixtures of air and SF/sub 6/. 13 refs., 12 figs., 1 tab.

Recovery of impact loaded samples is extremely difficult owing to the highly destructive post-shock environment. A variety of techniques have been introduced to accomplish this task for both organic and inorganic samples. The design principles underlying these techniques and the practical limitations encountered in applications are described. 3 figs.

Over the past several decades, many researchers have contributed to present understanding of the flashover of electrically stressed insulators in vacuum, and a wealth of theories have been proposed to explain the many surprising attributes of this complex breakdown mechanism. Surface flashover appears to comprise at least two distinct phenomena which can be distinguished as being cathode-initiated or anode-initiated, with the former having received by far the most attention. Several models describing cathode-initiated flashover have been built on the pioneering work of Boersch and coworkers, published in 1963, and credit the breakdown mechanism to the action of an intense secondary-electron-emission avalanche on the insulator surface. Other researchers consider the electron avalanche to be only partially, if at all, responsible, and invoke various hot-carrier effects in the insulator bulk, the surface interfacial region, or in a layer of gas adsorbed on the insulator surface. Anode-initiated flashover, which contends with the cathode-initiated variety for the breakdown of insulators of conventional design, is thought to involve bulk breakdown in a way related to treeing failure. In spite of the considerable effort applied to understanding vacuum surface flashover, no single theory appears capable of explaining all the data, and new and often unexpected observations continue to be made. 42 refs., 6 figs.

The need for ever-increasing miniaturization of airborne instrumentation through the use of surface mounted components closely placed on printed circuit boards highlights problems with traditional board cleaning methods. The reliability of assemblies which have been cleaned with vapor degreasing and spray cleaning can be seriously compromised by residual contaminants leading to solder joint failure, board corrosion, and even electrical failure of the mounted parts. In addition, recent government actions to eliminate fully halogenated chlorofluorocarbons (CFC) and chlorinated hydrocarbons from the industrial environment require the development of new cleaning materials and techniques. This paper will discuss alternative cleaning materials and techniques and results that can be expected with them. Particular emphasis will be placed on problems related to surface-mounted parts. These new techniques may lead to improved circuit reliability and, at the same time, be less expensive and less environmentally hazardous than the traditional systems. 5 refs.

The Recirculating Linear Accelerator (RLA) uses ion-focusing to provide the radial confinement of the beam. At the ends of the ion- channel racetrack, a ramped vertical magnetic field will be required to keep the beam in the channel. A sector field, whose strength increases with distance from the channel axis, has been proposed to provide an energy bandwidth for the transport system. This manuscript reports on design studies for coil systems that produce the required fields. It also describes particle simulations in the combined IFR-B-field transport system to address the issues of energy bandwidth and emittance growth. 4 refs., 6 figs.

Are single event upsets an important vulnerability or lethality issue for strategic systems Neutron-induced single events have become a part of the vulnerability analysis for nuclear weapon environments, but there has been no serious consideration of proton-induced single events from neutron particle beam environments. Is this appropriate This paper examines this concept.

As a result of the popularity of using HyperCard to rapidly prototype equipment and computer interfaces on Macintosh personal computers, the need ensued to evaluate prototype usability by collecting subjects' interactive performance data in real-time. Sandia National Laboratories, in collaboration with Stone Design Software, has developed ProtoTymer, a HyperCard stack that can time and record users' interactive sessions with prototypes developed using HyperCard. While operating in the background, ProtoTymer records the times, locations, and targets (objects clicked) of a subject's inputs during an interactive session. At the conclusion of the session, the resultant data file can be reviewed, summarized, printed, or transferred to a spreadsheet for statistical or graphical analysis. This paper describes ProtoTymer's design approach, features, limitations, and considerations for future versions. 2 refs., 4 figs.

TORE SUPRA is a fairly large supra conducting Tokamak (R = 2.350 m and r = 0.800 m) and has an original goal to withstand a large power removal (25 MW) during a 30 second long pulse. The monitoring of the plasma density and of the particle balance will be partially controlled by the pump limiter system. Depending on the amount of convected plasma power on these limiter and of the upgrading of the total injected power, the limiters are designed to remove in excess of 8 MW at steady state. 3 refs., 4 figs.

We compare the hydrogen assisted cracking resistance of wrought PH 13-8 Mo stainless steel alloyed with 0.4 to 1.0 wt.% palladium to the conventional alloy when aged to yield strengths of 1170--1250 MPa. Pd is found both in solid solution in the martensitic phase and also in the form of randomly distributed, incoherent PdAl precipitates in the modified alloy. Interfacial segregation of Pd to grain boundaries and lath boundaries is not observed. Intergranular hydrogen cracking is suppressed with Pd in slow strain rate tests conducted during electrochemical hydrogen charging of precharged samples. Hydrogen permeation analyses indicate that hydrogen ingress is not inhibited by Pd but that bulk diffusion rates are lowered relative to the conventional alloy. These results are consistent with the creation of a strong hydrogen trap, most likely the uniformly distributed PdAl phase, which lowers the levels of interfacially segregated hydrogen. 15 refs.

From an interplay between theory based on the effective-medium scheme and experiments, an extremely simple picture has evolved which is capable of describing a vast number of experimental quantities related to interaction of hydrogen with metals, especially the trapping of hydrogen at defects. It is shown that the trap strengths are determined mainly by the interstitial electron density, and any open structures in the lattice leads to a trap, with the vacancies and voids being the strongest traps. It is also found theoretically and experimentally that up to six hydrogen atoms can be accommodated in a vacancy, and the change in trap strengths with occupancy has been determined. Recent results for the trapping of deuterium to defects in Pd are discussed. 29 refs., 5 figs.

Recent experimental works on the effect of dose rate on the total dose failure threshold of MOS devices have shown that the failure level is strategic environments may be less than the failure level measured in the laboratory by a factor of 3 to 10. This difference in dose rate response raises concerns about using laboratory sources to predict the radiation hardness in strategic environments. A solution to the problem of determining the total dose hardness of piece parts is to perform lot acceptance testing at relevant dose rates such that the time dependent effects can be directly observed. A low cost method of measuring the total dose hardness of piece parts in the laboratory at requisite dose rates is presented. 11 refs., 5 figs.

The propulsion working fluid for the containment closure used at the Nevada Test Site consists of a mixture of a driver gas and the hot detonation products from the shaped charge that cuts the wall of the storage vessel. Nitrogen had always been used as the driver gas. However, helium gas, because of its superior propulsion characteristics, has enabled us to design considerably heavier and stronger gates. Operational times can be equal to or less than operational times when nitrogen gas was used. Assume, maintaining the same functional time, that an appreciably stronger steel/aluminum composite gate is designed and developed. The gate consists of two 3/4-in.-thick, high-strength 4340 circular steel plates imbedded in the two sides of the 7075-T73 aluminum forging. Mechanical circular keys are used to ensure the effective transfer of horizontal shear loads from aluminum to steel. Three point bending experiments on small composite beams were conducted to determine the effectiveness of the mechanical keying system. Also explored was structural adhesive used as a bonding and shear transfer mechanism. 4 refs., 8 figs., 1 tab.

The Seismic Verification Program at Sandia focuses on designing and building seismic monitoring systems which could be deployed within the Soviet Union. To support this effort, Sandia also is involved in developing and testing seismic components, and in evaluating system performance and new monitoring techniques. Seismic studies conducted under the latter task concentrate on analyzing regional seismic signals, recorded within 2000 km of the source. In-country monitoring stations would be able to exploit these regional signals to improve on the capabilities of external stations at teleseismic ranges. The principal advantages which regional signals offer are greater amplitudes and broader frequency bands. However, such signals are more complex and less well understood than teleseismic records. Ongoing studies at Sandia will help define the performance which can be expected from an in-country network. Other studies are testing new monitoring concepts which may further improve in-country capabilities. This presentation gives a brief overview of some of these projects.

Two important areas of hydrogen combustion with uncertainties are identified: (1) high-temperature combustion and (2) flame acceleration and deflagration-to-detonation transition (DDT). The uncertainties associated with high-temperature combustion may affect phenomena in a least four different accident scenarios: the in-cavity oxidation of combustible gases produced by core-concrete interactions, the combustion of hydrogen following high pressure melt ejection, the possibility of local detonations, and combustion in the BWR Mark I and Mark II secondary containments. The uncertainty in the area of DDT has increased importance due to recent experimental results that show that the detonability limit is nominally at or near the flammability limit for some mixture conditions. How these uncertainties may affect various accident scenarios is discussed and recommendations are made to reduce these uncertainties. 35 refs., 8 figs., 2 tabs.

In this work high frequency SPICE models were developed to simulate the hysteresis and saturation effects of toroidal shaped ferrite core inductors and transformers. The models include the nonlinear, multi-valued B-H characteristic of the core material, leakage flux, stray capacitances, and core losses. The saturation effects were modeled using two diode clamping arrangements in conjunction with nonlinear dependent sources. Two possible controlling schemes were developed for the saturation switch. One of the arrangements used the current flowing through a series RC branch to control the switch, while the other used a NAND gate. The NAND gate implementation of the switch proved to be simpler and the parameters associated with it were easier to determine from the measurements and the B-H characteristics of the material. Lumped parameters were used to simulate the parasitic effects. Techniques for measuring these parasitic are described. The models were verified using manganese-zinc ferrite-type toroidal cores and they have general applicability to all circuit analysis codes equivalent function blocks such as multipliers, adders, and logic components. 7 refs., 22 figs.

Knowledge of coal molecular structure is important in the understanding of coal reactivity. Computer-aided Molecular Design (CAMD) has been used to create and study three-dimensional models of several postulated coal structures (Given, Wiser, Solomon, and Shinn). Using molecular dynamics calculations, the minimum-energy conformations for each structural model have been compared. The physical densities of the minimum-energy conformations have been calculated, and are in agreement with experimental evidence. The frequencies of cross-linking hydrogen bonds have been evaluated for these structures. Finally, we have also begun to use CAMD to study model polymeric compounds, whose structure and reactivity may give new insights into coal conversion processes. 15 refs., 5 figs., 2 tabs.

Transient burning of TiH/sub X//KClO/sub 4/ in a closed system is formulated including the effect of condensed species. Thermodynamic properties are evaluated using both BLAKE and TIGER computer codes. Three different equations of state for gaseous species are used and their effect on the burning rate is evaluated. For more accurate transient burning analysis, a pressure dependent covolume for gaseous species is generated. The effect of pressure dependent covolume as well as the condensed species on transient burning is evaluated. Both parameters are found to be important when the burning rate at high loading densities in a closed system is considered. At high loading densities, condensed species become important not only because of the their effect on thermodynamic properties but also due to the volume occupied by these species. 11 refs., 2 figs., 2 tabs.

The winding process is encountered frequently in manufacturing, such as winding of polymer films and paper, laminated pressure vessel construction, and the manufacture of wound capacitors. The winding of capacitors will typically involve hundreds of plies of conductor and dielectric wound over a core. Due to the large number of layers, the calculation of the mechanical studies within a wound capacitor is a significant computational task. The focus of Part II of this paper is the formulation and application of optimization techniques for the design of wound capacitors. The design criteria to be achieved is a specified uniform wound tension in a capacitor. The paper will formulate an optimization statement of the wound capacitor design problem, develop a technique for reducing the numerical calculation required to repeatedly analyze the capacitor as required by the optimization algorithm, and apply the technique to an example. 4 refs., 13 figs., 4 tabs.

Horizontal stress directions (azimuths) determined from anelastic strain recovery (ASR) and differential strain curve analyses (DSCA) were compared with those from wellbore breakouts detected by borehole televiewer and oriented caliper logs. The ASR/DSCA techniques appear to be more sensitive then the log techniques and provided stress azimuth predictions at depth intervals where the log data did not. Stress azimuth determinations were also made from other core analyses techniques, which, like ASR/DSCA, are associated with the formation of stress release microcracks. Preliminary insights were obtained in the applicability of these other techniques. This work provides information on the stresses at two well sites 3.6 miles apart in Western Colorado; and showing the comparative data in this context provides information on how to apply these techniques and provides an understanding of the apparent influence of geologic effects (topography, depositional environment) on the stresses. 28 refs., 10 figs., 3 tabs.

This paper discusses a new telerobotic control concept which couples human supervisory commands with computer reasoning. The control system is responsive and accomplishes an operator's commands while providing obstacle avoidance and stable controlled interactions with the environment in the presence of communication time delays. This provides a system which not only assists the operator in accomplishing tasks but modifies inappropriate operator commands which can result in safety hazards and/or equipment damage. Research and development of this concept is being carried out in the Telerobotics Research Laboratory at Sandia National Laboratories. 12 refs., 4 figs.

After a decade of photovoltaic system research, most system related issues have been successfully resolved. Current system research activities are now oriented toward maintaining and updating the comprehensive database on system performance established by previous research efforts, integrating new components into system designs, and transferring the accumulated information to industry and users of the technology. This paper presents a brief overview of the status of system research in the United States, emphasizing three key activities - field evaluation, balance-of-system hardware development, and technology transfer. 5 refs., 2 tabs.

Over the past decade, Sandia National Laboratories has managed the Department of Energy (DOE)-sponsored programs for the development of the sodium/sulfur battery technology. Two DOE offices have provided support for these programs: the Office of Energy Storage and Distribution (OESD) and the Office of Transportation Systems (OTS). The ultimate goal of these ongoing efforts is to develop and demonstrate high performance, cost-effective systems suitable for both stationary and mobile applications. A part of Sandia's responsibility is to evaluate the status of the technologies and to address specific problems that are encountered during the development process. The number and level of effort devoted to these tasks are scaled such that the funding emphasis is given to the contracted engineering development programs. Two of the major safety-related concerns with sodium/sulfur EV batteries are the potential consequences associated with large temperature increases and vehicle accidents. The first three tasks represent Sandia's initial effort to help identify effective methods to limit the temperature rise in the battery during both expected and unexpected conditions and to assess one possible result of a vehicle accident. Descriptions of each task along with selected results are given in the following sections. 4 figs., 2 tabs.

With increasing demands on system requirements, designers must look for new alternatives to successfully complete their goals. One alternative that offers designers many benefits is ASICs. They maximize device functionality while minimizing system space. Also as operating frequencies approach gigahertz speeds, ASICs allow specialized placement of functional blocks on chip to minimize propagation delays of the signal. At Sandia, we found these requirements forcing us to look at ASICs fabricated in GaAs.

The supercomputer industry is at a crossroads. While its traditional markets have become relatively mature, the industry is becoming more competitive, especially with the challenge from Japan. The industry can either fight over this stable market or dramatically expand the market. The choice is obvious, but what are these new markets and how to approach them. This paper addresses these issues. First, it explains how the traditional definition of a supercomputer seriously constrains its market. An alternate definition opens up a much larger, emerging market. Second, it describes a market segmentation two barriers preventing customer in these new segments from using supercomputing and describes mechanisms to reduce and/or eliminate these barriers. Third, it discusses the portfolio analysis strategy to determine the markets in these new segments on which to concentrate. Obviously, parts of manufacturing are key targets. Finally, it draws some conclusions in terms of two scenarios -- one which describes a healthy, growing US supercomputer industry, the alternative showing the industry rapidly following the footsteps of the US consumer electronics industry. 6 refs.

Thin cathode coatings have been shown to be effective in suppressing pulsed breakdown in vacuum. Coatings are normally plastics, although some inorganics have been used. Thicknesses range from on the order of a micron to several mils (1 mil = 25.4 /mu/m). Pulse lengths from 10 ns to more than 1 /mu/s have been studied. 2 refs., 3 figs.

Data from an array of sixteen electric-field sensors have been used to evaluate the potential benefits to lightning warning systems of processing ''old'' data as well as data from off-site sensors. These specific topics are approached from a broad decision-theoretic viewpoint. 4 refs., 10 figs.

Low coulombic efficiencies of zinc/bromine redox batteries have been attributed to migration of bromine and negatively charged bromine moieties through the microporous separator used to separate the catholyte from the anolyte. While it has been demonstrated that improvements in coulombic efficiency can be achieved by replacing the microporous separator with a cationic ion exchange membrane, these membranes are expensive and/or not sufficiently conductive to be practicable. We have found that the rate of bromine permeation can be reduced by two orders of magnitude with minimal decreases in conductivity by impregnating commercial microporous polyethylene type separators with sulfonated polysulfone, a cationic polyelectrolyte that was developed in earlier work for other redox storage batteries. 5 refs., 1 fig., 1 tab.

The phenomenon of molten fuel-coolant interaction (FCI) is of considerable interest in many industrial processes where hot molten material may come in contact with water, including the pulp and paper, aluminum, steel, and nuclear power industries. The nature of the FCIs can range from mild film boiling, through energetic boiling, up to a violent vapor explosion. In the nuclear power industry, FCIs are of interest because of their possible consequences during hypothetical light water reactor core meltdown accidents. These interactions may occur under a variety of conditions either within the reactor vessel or in the reactor cavity. The IFCI computer code is being developed to investigate the FCI problem at large scale using a two-dimensional, four-field hydrodynamic framework and physically based models. IFCI will be capable of treating all major FCI processes in an integrated manner. The hydrodynamic method and physical models used in IFCI are discussed. Results from a test problem simulating a generic pouring mode experiment are presented. 39 refs., 10 figs., 1 tab.

Design and analysis of spacecraft power systems have been difficult to perform because of the lack of circuit level models for nonlinear inductive elements. This paper reviews some of the models which have been proposed, their limitations, and applications. An improved saturation dependent model will be described. The model has been implemented in SPICE and with a commercial circuit program and demonstrated to be satisfactory in both implementations. 3 refs., 9 figs.

Vibration testing in a centrifuge acceleration field (up to 50 gs) can be accomplished in either of two axes relative to the centrifuge acceleration with a modified, commercially available, electrodynamic shaker and the use of a specially designed orthogonal motion converter. Fixing the shaker armature axis in-line with the centrifuge arm (head towards the pivot) keeps the inertial forces on the head in the one direction which can be offset with servo controlled pneumatic bags located beneath the shaker head. Testing in an axis perpendicular to the principal axis is accomplished with the orthogonal motion converter which is driven by the shaker head. Copyright © 1989 Society of Automotive Engineers, Inc.

For estimating the global elasto-plastic structural response of critical concrete structures subjected to an aircraft crash, the time dependent impact force of a flat rigid barrier against a normally impacting aircraft was first evaluated and then the response, to the impact force, was calculated. In this approach, a significant problem was to determine the impact force for the aircraft against a rigid target. A review of the method proposed to determine the impact forces showed that all were based on analytical methods. However, in these analytical methods, there were many assumptions and many questions remained to be answered. Because of the uncertainty involved in the analytical prediction of the impact force, a full- scale aircraft impact test was performed and an extensive suite of response measurements was obtained. In this paper, these measurements are analyzed to evaluate the impact force accurately. Also, the results were used to evaluate existing analytical methods for prediction of the impact force. 7 refs., 10 figs.

The hydrostatic pressure dependence of the /beta/ molecular relaxation process of polyvinylidene fluoride (PVDF) has been investigated to 20 kbar. This relaxation is known to have a strong influence on the electrical and mechanical properties of PVDF. The observed large slowing down of the relaxation process is discussed in terms of the Vogel/endash/Fulcher equation. There is an increase in both the energy barrier to dipolar motion and the reference temperature (T/sub 0/) for the kinetic relaxation process which represents the ''static'' dipolar freezing temperature for the process.

Whether upgrading or developing a security system, investing in a solid state video recorder may prove to be quite prudent. Even though the initial cost of a solid state recorder may be more expensive, when comparing it to a disc recorder it is practically maintenance free. Thus, the cost effectiveness of a solid state video recorder over an extended period of time more than justifies the initial expense. This document illustrates the use of a solid state video recorder as a direct replacement. It replaces a mechanically driven disc recorder that existed in a synchronized video recording system. The original system was called the Universal Video Disc Recorder System. The modified system will now be referred to as the Solid State Video Recording System. 5 figs.

Past experience in addressing the insider threat has led to the development of general principles for mitigating the insider threat while minimizing adverse impacts on site operations. Among the general principles developed was the requirement for real time tracking of personnel and material. A real time system for personnel and material tracking will aid in mitigating the insider threat by providing critical information regarding the movement and location of personnel and material. In addition, this system can provide an early detection mechanism for potential insider actions. This paper describes the development, operation, and performance of a technology-based system which utilizes radio frequency transmitters to achieve the real time tracking of personnel and material. The major elements of this system are personnel tracking credential which cannot be removed from an authorized individual without an alarm being sounded, and material control device which is utilized to control and monitor access to material. These elements form an insider protection system through the use of software which establishes the ''rules'' under which the system will operate. The performance of this system has been evaluated under both laboratory and operational settings in order to: (1) demonstrate the system's ability to successfully control access to material and areas by personnel, and (2) provide information regarding the status of materials in transit and storage. 3 refs., 1 fig.

The problem of determining the mechanical states inside wound capacitor rolls is addressed through the application of two dimensional, linear elasticity. Allowances are made for heterogeneous wound construction of the capacitor, orthotropic material behavior of the capacitor constituents, and arbitrary winding tension. A key element in the formulation is the derivation of material properties for a wound, orthotropic layer which is equivalent in behavior to a stack of dissimilar plies such as are actually wound on the capacitor simultaneously during one turn of the mandrel. The dissimilar plies are necessary by virtue of the conductor and dielectric materials which must be present in a capacitor. The derivation of predictive equations is based on winding the equivalent layer on an appropriate mandrel, followed by a recovery of the individual ply responses. The capability to explicitly calculate the winding tensions which would be necessary to produce a required wound tension dependence upon capacitor radius is also developed. Numerical results for typical capacitor design and construction are presented, and justification for the application of optimization theory in capacitor development is demonstrated. 4 refs., 5 figs.

The Nuclear Engineering Department of National Tsing Hua University organized a workshop on Severe Accident Management. The workshop was sponsored by Taiwan Power Company and was held at Taipei, Taiwan from July 31 to August 11, 1989. The topics covered in the workshop included the general in-vessel LWR severe accident phenomena, containment responses and performances under severe accident conditions, results of Level 1 PRAs of three Nuclear Power Plants at Taiwan, and also two lectures related to the NUREG-1150 report just published by US NRC. This presentation covers these two lectures.

Recent experiences in operating nuclear plants in the United States have demonstrated the need for an in situ cable condition monitoring technique that can assess whether installed, low-voltage, unshielded cables have local damage that could compromise their ability to function under normal and accident service conditions. This paper summarizes current US programs that have been initiated to develop a technological basis for monitoring cables with local degradation. 7 refs.

An axial flow turbine mass model has been developed and used to study axial flow turbines for space power systems. Hydrogen, helium-xenon, hydrogen-water vapor, air, and potassium vapor working fluids have been investigated to date. The impact of construction material, inlet temperature, rotational speed, pressure ratio, and power level on turbine mass and volume has been analyzed. This paper presents the turbine model description and results of parametric studies showing general design trends characteristic of any axial flow machine. Also, a comparison of axial flow turbine designs using helium-xenon mixtures and potassium vapor working fluids, which are used in Brayton and Rankine space power systems, respectively, is presented. 9 refs., 4 figs., 2 tabs.

Energetic fuel-coolant interactions may occur in a nuclear reactor in the event that molten fuel comes in contact with the reactor coolant water. Reliable mechanistic models of these interactions have yet to be developed and so relatively simple thermodynamic models have been proposed for estimating the conversion of thermal energy to mechanical work. The present paper outlines a generalized thermodynamic model for fuel-coolant interactions which accounts for variable thermodynamic properties as well as the effect of latent heat in the fuel. The variable property model is shown to provide an upper bound (most conservative) estimate of the conversion efficiency compared to other formulations appearing in the literature. 7 refs., 5 figs.

Unconfined heterogeneous two-phase detonations in liquid droplet-air mixtures are investigated. The liquid fuel is placed in a V-shaped channel and is dispersed into the atmosphere to form a cloud by an explosive detonating cord laid along the bottom vertex of the channel. An aerosol cloud 7 m high by about 1.5 m averaged width can be generated in this way with a typical mass ratio of fuel to explosive charge of 150. In the present study the length of channel used is typically 10 m giving a detonable fuel-air cloud of about 100 m/sup 3/. The propylene-oxide driver and the test fuel are disseminated simultaneously. Detonation in the propylene-oxide section is initiated by the sheet explosive and the detonation then transmits from this driver section into the rest of the cloud formed from the test fuel. For insensitive fuels requiring a larger cloud dimension, two parallel fuel troughs spaced 1.2 m apart are used. It is found that propylene-oxide and nitrated hydrocarbon fuels detonate quite readily. For the case of propylene-oxide, significant vaporization of the aerosol is observed prior to initiation so that detonation is essentially in the gas phase. 15 refs., 4 figs.

We find a strong correlation between the preirradiation 1/f noise of pMOS transistors and their radiation hardness. This suggests that current fluctuations may provide a useful, nondestructive probe of defects in MOS devices. 18 refs., 4 figs., 1 tab.

It is shown how standard ..delta..Vth and mobility measurements made on otherwise identical n- and p-channel transistors can be combined to accurately estimate radiation-induced ..delta..V/sub ot/ and ..delta..V/sub it/. Applications of the method are described. 12 refs., 2 figs.

Nuclear microprobe analysis (NMA) is a unique form of microbeam analysis in that it combines high lateral resolution with the high depth resolution techniques of conventional ion beam analysis (IBA) to nondestructively determine sample composition in three dimensions. By using depth sensitive IBA techniques (e.g., Rutherford Backscattering Spectrometry (RBS), Enhanced Backscattering Spectrometry (EBS) or Elastic Recoil Detection (ERD)), NMA finds its greatest utility in analyses requiring the following information: (1) 1--100 ppM sensitivity, (2) nondestructive three-dimensional depth profiling, and (3) quantitative light element analysis (e.g., the first two rows of the periodic table). This paper demonstrates the continuing evolution of NMA capabilities through two examples. First, the unique capabilities afforded NMA are shown in a simple yet accurate method to measure both oxygen and metal atom concentrations in Y-Ba-Cu-O alloys with micro-area ion beam analysis. Second, a NMA of buried tungsten lines in a silicon wafer demonstrates the complementary nature of information determined by NMA and scanning electron microscopy (SEM). 9 refs., 2 figs.

The ASSESS Neutralization Analysis module (Neutralization) is part of Analytic System and Software for Evaluation of Safeguards and Security, ASSESS, a vulnerability assessment tool. Neutralization models a fire fight engagement security inspectors (SIs) and adversaries. Results are based on probability of neutralization, P(N), which estimates the likelihood that SIs will win, given that SIs interrupt the attackers and begin an armed engagement. The calculating engine of the module is the Brief Adversary Threat Loss Estimator, BATLE. Engagements can have as many as thirty combatants on a side. Reinforcements may be introduced or combatant characteristics may be changed as many as ten times in one engagement. Inputs may be made with or without programmed guidance to the user. Combatant characteristics come from a modifiable library. Seven different characteristics can be independently specified for each combatant. Graphs of time distributions and studies of the sensitivity of P(N) to any combatant characteristic of either SIs or adversaries can be requested. Output files from Neutralization are used by Outsider Analysis to produce probability of security system win. 4 refs., 12 figs., 2 tabs.

The Facility Descriptor (Facility) module is part of the Analytic System and Software for Evaluating Safeguards and Security (ASSESS). Facility is the foundational software application in the ASSESS system for modelling a nuclear facility's safeguards and security system to determine the effectiveness against theft of special nuclear material. The Facility module provides the tools for an analyst to define a complete description of a facility's physical protection system which can then be used by other ASSESS software modules to determine vulnerability to a spectrum of insider and outsider threats. The analyst can enter a comprehensive description of the protection system layout including all secured areas, target locations, and detailed safeguards specifications. An extensive safeguard component catalog provides the reference data for calculating delay and detection performance. Multiple target locations within the same physical area may be specified, and the facility may be defined for two different operational states such as dayshift and nightshift. 6 refs., 5 figs.

Past experience in addressing the insider threat has led to the development of general principles for mitigating the insider threat while minimizing adverse impacts on site operations. Among the general principles developed was the requirement for real time tracking of personnel and material. A real time system for personnel and material tracking will aid in mitigating the insider threat by providing critical information regarding the movement and location of personnel and material. In addition, this system can provide an early detection mechanism for potential insider actions. This paper describes the development, operation, and performance of a technology-based system which utilizes radio frequency transmitters to achieve the real time tracking of personnel and material. The major elements of this system are a personnel tracking credential which cannot be removed from an authorized individual without an alarm being sounded, and a material control device which is utilized to control and monitor access to material. These elements form an insider protection system through the use of software which establishes the ''rules'' under which the system will operate. The performance of this system has been evaluated under both laboratory and operational settings in order to: (1) demonstrate the system's ability to successfully control access to material and areas by personnel, and (2) provide information regarding the status of materials in transit and storage. 3 refs., 1 fig.

Monte Carlo methods are used in a variety of applications such as risk assessment, probabilistic safety assessment, and reliability analysis. While Monte Carlo methods are simple to use, their application can be laborious. A new microcomputer software package has been developed that substantially reduces the effort requires to conduct Monte Carlo analyses. The Sensitivity and Uncertainty Analysis Shell (SUNS) is a software shell in the sense that a wide variety of application model can be incorporated into it. SUNS offers several useful features including a menu-driven environment, a flexible input editor, both Monte Carlo and Latin Hypercube sampling, the ability to perform both repeated trials and parametric studies in a single run, and both statistical and graphical output. SUNS also performs all required file management functions. 9 refs., 6 figs., 1 tab.

Inorganic thin films with molecular sieving properties have been formed by embedding microcrystals of zeolite Y and chabazite in a glassy silica matrix. The silica matrix was derived from sols prepared from tetraethylorthosilicate hydrolyzed under either acidic or basic conditions in alcoholic solution. Dip-coating, deposition of suspensions, or coating of zeolite dispersions with the glassy silica matrix were used to create the zeolite-silica films. The access of different probe molecules into the zeolitic part of the thin film was examined with in situ FTIR techniques and temperature-programmed-desorption studies. With all combinations of deposition techniques and silica matrices, the resulting films showed the molecular sieving properties of the parent zeolite. © 1989, Elsevier Science & Technology. All rights reserved.

Stand-off hypervelocity particle shields offer potential weight savings of an order of magnitude or more over conventional homogeneous armors. Based on an earlier complete model for the design and optimization of a stand-of shield system, a more restricted model appropriate for retrofit shields is described. Procedures to minimize the shield mass are provided, and scaling laws for many of the important parameter relationships are illustrated. 6 refs., 5 figs.