Publications

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. 13 figs.

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 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.

Our division is charged with instrumentation development in support of underground testing. We find it necessary to be able to evaluate the performance of waveform digitizing systems with sampling rates from a few kilohertz to more than a gigahertz. We have been developing an integrated system which can provide quantitative results on the performance of systems and subsystems. Here we describe a system which is controlled by a Microvax II with instrumentation control through the IEEE-488 buss. The evaluation procedures are aimed at being consistent with a new Trial Waveform Digitizer Standard generated by the Waveform Measurements and Analysis committee appointed by the Instrumentation and Measurement Society of IEEE. This standard has been recently accepted by the IEEE and will be published in the next few months. Attention is given to the accurate measurement of effective-bit performance and differential nonlinearity of waveform digitizers. 3 refs., 14 figs.

Static and dynamic analyses of an impact limiter for a spent fuel cask have been performed using the finite element analysis code PRONTO2D (Taylor and Flanagan, 1987). The impact limiter contained wood as the energy absorbing material, with the wood confined by a cylindrical metal outer skin and sixteen metal stiffeners (gussets). The object of these analyses was to determine how the wood interacts with the metal stiffeners and to determine if the impact limiter would behave differently under static versus dynamic loading conditions. Originally, the metal gusset strength was assumed to be limited by the elastic buckling load. Further analysis showed that the gusset strength was not limited to the elastic buckling load and that each gusset contributed significantly to the impact limiter's strength. The current analyses investigated the strength of a flat plate or gusset used in impact limiter systems. 3 refs., 6 figs.

A two-dimensional synthetic aperture radar (SAR) phase correction algorithm is described as a natural extension of a one-dimensional technique developed previously. It embodies many similarities to phase gradient speckle imaging and incorporates improvements in phase estimation. Diffraction limited performance has been obtained on actual SAR imagery regardless of scene content or phase error structure. The algorithm is computationally efficient, robust, and easily implemented on a general purpose computer or special purpose hardware. 13 refs., 1 fig.

We describe a Silicon-on-Insulator (SOI) structure for high voltage BICMOS uniquely suited to the use of porous silicon (PS). In this SOI structure, bulk, high speed bipolar devices are readily integrated with CMOS high voltage and logic devices (smart power). To investigate the processing compatibility of PS with this structure, we measured breakdown strength and etch rate of thermally treated PS in 7:1 buffered oxide etch (BOE) and determined that they can approach values typical of thermal silicon oxides/nitrides. 7 refs., 2 figs.

The solidification behavior of Alloy 718 and other Nb-bearing austenitic superalloys has been examined using an integrated analytical approach. All alloys of this type begin solidification with the formation of Nb-lean austenitic dendrites. Interdendritic eutectic-type solidification constituents involving MC-type carbides and a Nb-rich Laves phase occur in these alloys. The ..gamma../Laves eutectic constituent terminates solidification in these alloys. Nb is the dominant element in the evolution of solidification microstructure with C and Si affecting the amounts of ..gamma../MC and ..gamma../Laves constituent observed. Simple solidification models predict reasonably well the amount of eutectic constituent observed. 11 refs., 9 figs., 2 tabs.

An entry control system (ECS) allows the movement of authorized personnel and material through normal routes while detecting and delaying movement of unauthorized personnel and contraband. This paper presents an overview of several unique design and operating principles used in the implementation of a positive identity entry control system utilizing proximity cards. The system design incorporates distributed processing to support geographically separated entry points and redundancy such that no single point failure will shut down operations. The functionality and integration of the photo identification system, the visitor authorization system, and the access control and contraband detection systems will be discussed. Systems unique features such as temporary badge issue for lost or forgotten badges at entry points using video lookup, visitor processing, and ergonomic and environmental considerations for the design of the proximity card based entry lane will be covered. 6 figs.

Effective implementation of an insider protection program in light of the new directives can be accomplished through sound planning and a strong management commitment to meaningful improvements. Good planning, with a firm set of goals and objectives that have reasonable milestones, are essential elements in the effective implementation of new requirements. This paper describes a structured approach to achieving effective and acceptable program implementation.

Analysis of the electrohydrodynamic (EHD) equations of motion of a planar liquid-lithium surface in the presence of a normal electric field suggest that liquid lithium may provide a large-area ion source for intense ion-beam diodes. Such sources are being developed for the Particle Beam Fusion Accelerator II at Sandia National Laboratories. In this paper, theoretical and experimental studies of the planar EHD ion source will be reviewed. When a planar liquid surface is subjected to an electric field of sufficient magnitude, EHD instabilities produce an array of cusps on the surface. The electric field enhancement at the apex of each cusp is sufficient to permit field evaporation of ions. The time delay between application of the electric field and ion emission depends on the magnitude and rate of increase of the applied electric field, and on the initial amplitude of the surface perturbation. Above 10 MV/cm, theory indicates that field emission will occur on a nanosecond time scale and that the characteristic spacing of emitters will be less than one micrometer. At these fields, the source should have an intrinsic divergence of less than 6 mrad and the effects of space charge from neighboring emitters should not inhibit emission significantly. Experimental measurements of wavelength and cusp-formation-times for water and ethanol at electric fields near the critical field for instability have agreed well with theory. 11 refs., 4 figs.

Bipolaronic superconductivity requires two exceptional circumstances. First, at least some charge carriers must form bipolarons. Second, these bipolarons must be mobile (move coherently). However, beyond quasi-one-dimensional electronic systems, bipolarons have heretofore always been found to be ''small.'' Small (bi)polarons are very compact (bi)polarons that localize rather than move coherently. Thus, small bipolarons are not suitable carriers for bipolaronic superconductivity. However, in analogy with the case of large polarons, less compact bipolarons, ''large'' bipolarons, are expected to be mobile. These observations lead one to ask if and when large bipolarons can form in multi-dimensional electronic systems. Here the results of studies of the formation, motion and superconductivity of large bipolarons are summarized. 5 refs.

The realization that structures in Nature often can be described by Mandelbrot's ''fractals'' has led to a revolution in many areas of physics. The interaction of waves with fractal systems has, understandably, become intensely studied since scattering is the method of choice to probe delicate fractal structures such as chainlike particle aggregates. Not all of these waves are electromagnetic: neutron scattering, for example, is an important complementary tool to structural studies by x-ray and light scattering. Since the phenomenology of small-angle neutron scattering (SANS), as it is applied to fractal systems, is identical to that of small-angle x-ray scattering (SAXS), it falls within the scope of this Working Paper. 9 refs.

Sandia National Laboratories, in conjunction with its participation in the American National Standards Institute (ANSI) writing groups, has undertaken to provide an experimental and analytical basis for the design of components of radioactive materials packages to resist normal transport shock and vibration loads. Previous efforts have resulted in an overly conservative shock spectra description of the loads in the tie-downs and cask attachment points anticipated during normal shipment. The present effort is aimed at predicting the actual loads so that the design basis can be accurately determined. This goal is being accomplished with road simulator and over-the-road tests and the development of an analytical model. This model is used to parametrically evaluate and envelop the transportation systems' responses. The parameters to be varied include damping, stiffness, geometry, and cargo mass. The over-the-road tests provide operational data that are used to validate the selection of environments for the road simulator tests. The road simulator tests provide verification for the model. This verification is accomplished since the road simulator tests provide not only the system response which can be measured in over-the-road tests but also the system input. Finally, when the model has been verified, it can be used to vary parameters to envelop a wide range of normal transport conditions.

Sandia National Laboratories has developed a variety of command, control, and display systems for a broad spectrum of users. This paper briefly describes the latest systems developed for the Department of Energy (DOE), the Department of Defense (DOD), and the Department of State (DOS) applications. Applications covered vary from relatively small facilities to large complex sites. 3 refs., 6 figs.

Novel methods/techniques for the detection of explosives are briefly described. The methods include vapor detection, preconcentrators, chemiluminescence detectors and microwave detectors. (CBS)

An inherent aspect of active array radars is the use of large numbers -- typically hundreds -- of transmit/receive (T/R) modules. The implementation of this technology at Sandia has created new challenges for the tester designer. Foremost among these challenges is the need to design T/R module testers which can accommodate such large numbers of devices-under-test (DUTs). This task is complicated by the fact that state-of-the-art T/R modules are extremely sophisticated and require a broad spectrum of tests for adequate evaluation. The Sandia T/R module operates in Ku band and consists of a transmitter, receiver, programmable phase shifter, programmable attenuator, modulator, switched limiter, and gate-array controller. The programmable phase shifter is common to both the transmitter and receiver, but the attenuator is unique to the receiver. The instruments required for the tests include a network analyzer, a spectrum analyzer, a noise figure meter, a peak-power meter, and an automated tuner system. The key to a successful tester is in integrating all of the above instruments such that the desired measurements can all be performed from a single, two-port, tester-to-DUT connection. The natural consequence of such a design is that some measurements will have to be de-embedded from the integrated test setup. This paper addresses both the tester's instrument integration and the resulting de-embedding concerns. 2 figs.

In the past several years a wealth of decay data has been obtained and reported, much of it in ''Decay Data of the Transactinium Nuclides'', IAEA Technical Reports Series No. 261 (1986). The decay data for the daughters of /sup 238/U have been notable by their absence in such compilations; and since there is a need for such data, a set of experiments has been performed to measure the gamma-ray emission probabilities. Uranium samples of known mass and isotopic concentration in aqueous solution are analyzed with a high-purity germanium gamma-ray spectrometer. Various samples have also in solution multi-line calibration sources with well-known relative intensities. The well-known emission probabilities of the /sup 235/U gamma rays are used to provide an absolute intensity reference. Since self-absorption of the sample is included in the effective detector efficiency, there is not need for a separate calculation of this absorption. Gamma-ray emission probabilities for the energy range 63 to 1938 keV are reported. Sources of error, including those in the efficiency curve, are discussed. 11 refs., 5 figs., 4 tabs.

Thirty-nine (39) bipolar device lots (195 devices) were tested for peak photocurrent. Difference in average photocurrent between lots of same device types was less than a factor of three in all cases. 4 figs.

Lot acceptance tests are evaluated for nonhardened CMOS devices for low total-dose space applications. Examples are presented for cases in which gate- or field-oxide leakage dominates device response. 12 refs., 3 figs.

Spent fuel transportation casks have arrived at final destinations with removable surface contamination levels in excess of regulatory limits, although pre-transport surveys indicated removable contamination levels were well below these limits. The control of this in-transit ''weeping'' of surface contamination on pool-loaded spent fuel transport casks is of particular concern to both the US Department of Energy (DOE) and the US Nuclear Regulatory Commission (NRC). Weeping, also known as sweating, is the transformation of fixed radioactive particulates on an exterior surface of transport cask to a removable state. Weeping has been observed sometime after a cask is removed from a fuel pool and decontaminated. The weeping phenomenon is countered by time-consuming operational constraints and procedures which have a significant impact on cask turnaround times and occupational exposures at transport facilities. Further, the arrival of a contaminated cask results in negative public perceptions that are inconsistent with DOE and NRC goals. The objectives in resolving the technical issue of weeping are to identify specific causes of the weeping phenomenon, then to implement new cask design requirements and supporting operational procedures which will limit or inhibit the accumulation, retention, and in-transit conversion of fixed surface contamination. 6 figs., 1 tab.

To protect a security instrument such as a television camera from subversion by signal substitution, the data from the instrument are digitized and submitted to an authenticator. The digital data may then be transmitted in the clear over a non-secure medium. Appended to the data is a 10-bit authentication value based on the values of the data and a random authentication number. At the receiving end, the data are submitted to an identical authenticator. If it produces the same authentication value, the data are authentic. Such a scheme can only work if the instrument, the authenticator, and the link between them can be protected from tampering. This paper describes a tamper resistant container designed to protect a data authenticator and television camera against an adversary having sophisticated resources and complete design information. The container's design includes active elements to detect and report intrusion attempts in real time. It also includes passive elements to indicate upon later inspection that the container had been violated. 1 ref., 2 figs.

Considerable interest has been generated within the past several years concerning the use of new generation video motion detection (VMD) systems as exterior intrusion sensors. The new generation VMD systems advertise advanced video signal processing techniques and algorithms which are aimed at rejecting nuisance alarm sources inherent to the uncontrolled exterior environment. Older generation VMD systems used in an exterior environment tend to have high nuisance alarm rates. The high nuisance alarm rates of the older systems made them generally unacceptable for use as an exterior sensor. This paper discusses the results of continued field testing of new generation VMD systems. Field tests were conduced in an exterior perimeter zone application and an application looking at the exterior entrance of a building. Test results include each VMD system's detection capabilities and nuisance alarm characteristics for each particular application. Also site considerations such as lighting, cameras and zone layouts for exterior video motion detection are discussed. 1 ref., 14 figs., 1 tab.

The piezoelectric polymer, polyvinylidene di-fluoride (PVDF or PVF2), properly processed by the proprietary Bauer technique, is a material for a transducing element that can be used for a wide variety of stress, pressure, or temperature related measurements. Its versatility as a sensor requires especially careful attention to the special requirements for associated gauge packaging, installation, signal conditioning, recording, and analysis that are imposed by the particular diverse test conditions. Most applications reported to date have been for tests performed under laboratory conditions. But, the PVDF sensor has also been successfully used for stress wave measurement under adverse and often hostile field test conditions that require the use of lengthy transmission lines and allow only limited recording capability. This paper discusses one crucial aspect of field application -- measuring system characterization, and correction of signals distorted by systems of marginal frequency capability. 11 refs., 7 figs.

Radiation effects on polymers in the presence of air are characterized by complicated phenomena such as dose-rate effects and post-irradiation degradation. Most applications of polymeric materials in radiation environments involve air atmospheres. Taking account of oxidation effects and time-dependent phenomena is a necessity for understanding materials changes which occur during aging, and for dealing with issues of materials lifetime prediction, aging monitoring, materials selection, and material stabilization. Time-dependent radiation-degradation effects can be understood mechanistically in terms of: (1) features of the free radical chain-reaction chemistry underlying the oxidation, and (2) oxygen diffusion effects. A profiling technique has been developed to study heterogeneous degradation resulting from oxygen diffusion, and kinetic schemes have been developed to allow long-term aging predictions from short-term high-dose-rate experiments. These methodologies have been successfully applied for predicting degradation rates of a number of different materials under ambient nuclear environments. Low molecular weight additives which act either as free-radical scavengers or else as energy-scavengers are effective as stabilizers in radiation-oxidation environments. Non-radical oxidation mechanisms, involving species such as ozone, can also be important in the radiation-oxidation of polymers. 14 refs., 13 figs.

A comprehensive stress analysis was performed for a bimaterial plate subjected to a uniform change of temperature. The steel and brass portions of the specimen were bonded along a common edge. Whole-field measurements were made by high-sensitivity moire interferometry. A companion finite element numerical analysis of a similar body was conducted to help interpret the experimental results. The experiments documented a strong free-edge effect along the entire perimeter of the joint, an effect akin to a line singularity along the perimeter. High stresses in the edge-effected zone were determined from measurements, and enormous stress gradients were deduced by analysis. The largest stresses were found at the corner, where two edge-effected zones intersected. 5 refs., 8 figs.

Advanced titanium-aluminum intermetallic alloys (often simply called titanium aluminides) have certain properties which make them potentially attractive as advanced aerospace alloys. In order to utilize these alloys in engineering applications, it is necessary to process the alloys in a variety of ways including casting, hot forming and welding. All of these processes modify the microstructure of the alloy, which in turn directly influences the properties. The key to optimizing the alloy's properties is to control the microstructure by careful control of the processing parameters. Control for the microstructure requires a thorough understanding of the evolution of the microstructure, including elemental partitioning between the various phases which form in the alloy. Analytical electron microscopy (AEM) is an ideal way to characterize the microstructures on a fine spatial scale. Such high spatial resolution microanalysis is required to understand the microstructural evolution in these alloys. In this case, the alloy is a Nb modified Ti/sub 3/Al, and the partitioning behavior of interest is between a variety of ternary phases which are produced as a function of alloy cooling rate from a single homogeneous high temperature ..beta.. phase. The Nb is added to the alloy to enhance its performance, primarily through an improvement in ductility. In this work, the details of the procedure for quantitative analysis of these alloys are presented.

An applied B-field ion diode on PBFA II has produced a 17 TW proton beam for investigation of beam generation and transport physics pertinent to inertial confinement fusion experiments. Power was fed to the diode via two conical self-magnetically-insulated transmission lines that incorporated plasma opening switches. The diode utilized a pair of B-field coils in disc shaped cathodes to produce a 3 T axial B-field that insulated the 16 mm anode-cathode gap from electron loss. The 15-cm-radius anode was configured with a 5.5-cm-tall curved ion emitting region. A 2.6 MA ion beam originated from this region, was accelerated to 6 MV in the anode-cathode gap, and then transported ballistically toward the axis in a current neutralizing gas cell. The best transport (75%) occurred with narrow 5.5-cm-tall anode sources in which a 180 kJ proton beam was observed within 1.2 cm of the diode centerline. The FWHM of the beam focused at the centerline of the diode was 5 to 7 mm. This beam gave a peak proton power density of approximately 5 TW/cm/sup 2/. 12 refs., 8 figs.

The finite control volume method (FCVM) was successfully used to calculate both laminar and turbulent buoyancy driven flow of air in a square enclosure for Ra = 10/sup 3/ to 10/sup 8/. For laminar flow, comparisons of the computed solution with both experimental data and other numerical solutions are in excellent agreement. Comparisons of selected velocities and average Nusselt numbers with a ''benchmark'' solution presented by deVahl Davis are consistently within 4%. For turbulent flow, the agreement with another numerical solution is generally good, considering the large difference in the number of nodes employed. The agreement with extrapolated experimental correlations for the average Nusselt number was acceptable. 20 refs., 4 figs., 2 tabs.