Publications

MOS oxides have been fabricated by oxidation of silicon in N{sub 2}O. Processes studied include oxidation in N{sub 2}O alone, and two-step oxidation in O{sub 2} followed by N{sub 2}O. For both oxides, a nitrogen-rich layer with a peak N concentration of {approximately} 0.5 at. % is observed at the Si-SiO{sub 2} interface with SIMS. Electrical characteristics of N{sub 2}O oxides, such as breakdown and defect generation, are generally improved, especially for the two-step process. Drawbacks typically associated with NH{sub 3}-nitrided oxides such as high fixed oxide charge and enhanced electron trapping, are not observed in N{sub 2}O oxides, which is probably due to their smaller nitrogen content.

The Explosive Inventory and Information System (EIS) is being developed and implemented by Sandia National Laboratories (SNL) to incorporate a cradle to grave structure for all explosives and explosive containing devices and assemblies at SNL from acquisition through use, storage, reapplication, transfer or disposal. The system does more than track all material inventories. It provides information on material composition, characteristics, shipping requirements; life cycle cost information, plan of use; and duration of ownership. The system also provides for following the processes of explosive development; storage review; justification for retention; Resource, Recovery and Disposition Account (RRDA); disassembly and assembly; and job description, hazard analysis and training requirements for all locations and employees involved with explosive operations. In addition, other information systems will be provided through the system such as the Department of Energy (DOE) and SNL Explosive Safety manuals, the Navy`s Department of Defense (DoD) Explosive information system, and the Lawrence Livermore National Laboratories (LLNL) Handbook of Explosives.

This paper describes a method of reducing the mechanical stress caused when a ferrite pot core is encapsulated in a rigid epoxy. the stresses are due to the differences of coefficient of thermal expansion between the two materials. A stress relief medium, phenolic micro-balloon-filled, syntactic polysulfide, is molded into the shape of the pot core. The molded polysulfide is bonded to the core prior to encapsulation. The new package design has made a significant difference in the ability to survive temperature cycles.

This paper provides an overview of the methodology used in a probabilistic transportation risk assessment conducted to assess the probabilities and consequences of inadvertent dispersal of radioactive materials arising from severe transportation accidents. The model was developed for the Defense Program Transportation Risk Assessment (DPTRA) study. The analysis incorporates several enhancements relative to previous risk assessments of hazardous materials transportation including newly-developed statistics on the frequencies and severities of tractor semitrailer accidents and detailed route characterization using the 1990 Census data.

Protecting sensitive items from undetected tampering in an unattended environment is crucial to the success of non-proliferation efforts relying on the verification of critical activities. Tamper Indicating Packaging (TIP) technologies are applied to containers, packages, and equipment that require an indication of a tamper attempt. Examples include: the transportation and storage of nuclear material, the operation and shipment of surveillance equipment and monitoring sensors, and the retail storage of medicine and food products. The spectrum of adversarial tampering ranges from attempted concealment of a pin-hole sized penetration to the complete container replacement, which would involve counterfeiting efforts of various degrees. Sandia National Laboratories (SNL) has developed a technology base for advanced TIP materials, sensors, designs, and processes which can be adapted to various future monitoring systems. The purpose of this technology base is to investigate potential new technologies, and to perform basic research of advanced technologies. This paper will describe the theory of TIP technologies and recent investigations of TIP technologies at SNL.

Becoming aware of the significant events of the past four years and their effect on the expectations to international safeguards, it is necessary to reflect on which direction the development of nuclear safeguards in a new era needs to take and the implications. The lime proven monitoring techniques, based on quantitative factor`s and demonstrated universal application, have shown their merit. However, the new expectations suggest a possibility that a future IAEA safeguards system could rely more heavily on the value of a comprehensive, transparent and open implementation regime. Within such a regime, the associated measures need to be determined and technological support identified. This paper will identify the proven techniques which, with appropriate implementation support, could most quickly make available additional measures for a comprehensive, transparent and open implementation regime. In particular, it will examine the future of Integrated Monitoring Systems and Remote Monitoring in international safeguards, including technical and other related factors.

The upgrade of the TEXTOR tokamak at KFA Juelich was recently completed. This upgrade extended the TEXTOR pulse length from 5 seconds to 10 seconds. The auxiliary heating was increased to a total of 8.0 MW through a combination of neutral beam injection and radio frequency heating. Originally, the inertially cooled armor tiles of the full toroidal belt Advanced Limiter Test -- II (ALT-II) were designed for a 5-second operation with total heating of 6.0 MW. The upgrade of TEXTOR will increase the energy deposited per pulse onto the ALT-II by about 300%. Consequently, the graphite armor tiles for the ALT-II had to be redesigned to avoid excessively high graphite armor surface temperatures that would lead to unacceptable contamination of the plasma. This redesign took the form of two major changes in the ALT-II armor tile geometry. The first design change was an increase of the armor tile thermal mass, primarily by increasing the radial thickness of each tile from 17 mm to 20 mm. This increase in the radial tile dimension reduces the overall pumping efficiency of the ALT-II pump limiter by about 30%. The reduction in exhaust efficiency is unfortunate, but could be avoided only by active cooling of the ALT-II armor tiles. The active cooling option was too complicated and expensive to be considered at this time. The second design change involved redefining the plasma facing surface of each armor tile in order to fully utilize the entire surface area. The incident charged particle heat flux was distributed uniformly over the armor tile surfaces by carefully matching the radial, poloidal and toroidal curvature of each tile to the plasma flow in the TEXTOR boundary layer. This geometry redefinition complicates the manufacturing of the armor tiles, but results in significant thermal performance gains. In addition to these geometry upgrades, several material options were analyzed and evaluated.

Disposition of electric vehicle (EV) batteries after they have reached the end of their useful life is an issue that could impede the widespread acceptance of EVs in the commercial market. This is especially true for advanced battery systems where working recycling processes have not as yet been established. The DOE sponsors an Ad Hoc Electric Vehicle Battery Readiness Working Group to identify barriers to the introduction of commercial EVs and to advise them of specific issues related to battery reclamation/recycling, in-vehicle battery safety, and battery shipping. A Sub-Working Group on the reclamation/recycle topic has been reviewing the status of recycling process development for the principal battery technologies that are candidates for EV use from the near-term to the long-term. Recycling of near-term battery technologies, such as lead-acid and nickel/cadmium, is occurring today and it is believed that sufficient processing capacity can be maintained to keep up with the large number of units that could result from extensive EV use. Reclamation/recycle processes for midterm batteries are partially developed. Good progress has been made in identifying processes to recycle sodium/sulfur batteries at a reasonable cost and pilot scale facilities are being tested or planned. A pre-feasibility cost study on the nickel/metal hydride battery also indicates favorable economics for some of the proposed reclamation processes. Long-term battery technologies, including lithium-polymer and lithium/iron disulfide, are still being designed and developed for EVs, so descriptions for prototype recycling processes are rather general at this point. Due to the long time required to set up new, full-scale recycling facilities, it is important to develop a reclamation/recycling process in parallel with the battery technologies themselves.

The Safeguards Information Management System initiative is a program of the Department of Energy`s (DOE) Office of Arms Control and Nonproliferation aimed at supporting the International Atomic Energy Agency`s (IAEA) efforts to strengthen safeguards through the enhancement of information management capabilities. The DOE hopes to provide the IAEA with the ability to correlate and analyze data from existing and new sources of information, including publicly available information, information on imports and exports, design information, environmental monitoring data, and non-safeguards information. The first step in this effort is to identify and define IAEA requirements. In support of this, we have created a users` requirements document based on interviews with IAEA staff that describes the information management needs of the end user projected by the IAEA, including needs for storage, retrieval, analysis, communication, and visualization of data. Also included are characteristics of the end user and attributes of the current environment. This paper describes our efforts to obtain the required information. We discuss how to accurately represent user needs and involve users for an international organization with a multi-cultural user population. We describe our approach, our experience in setting up and conducting the interviews and brainstorming sessions, and a brief discussion of what we learned.

An input shaping scheme originally used to slew flexible beams via a tabletop D.C. motor is modified for use with an industrial-type, hydraulic-drive robot. This trajectory generation method was originally developed to produce symmetric, rest-to-rest maneuvers of flexible rotating rods where the angular velocity vector and gravitational vector were collinear. In that configuration, out-of-plane oscillations were excited due to centripetal acceleration of the rod. The bang-coast-bang acceleration profile resulted in no oscillations in either plane at the end of the symmetric slew maneuver. In this paper, a smoothed version of the bang-coast-bang acceleration is used for symmetric maneuvers where the angular velocity vector is orthogonal to the gravitational vector. Furthermore, the hydraulic robot servo dynamics are considered explicitly in determining the input joint angle trajectory. An instrumented mass is attached to the tip of a flexible aluminum rod. The first natural frequency of this system is about 1.0Hz. Joint angle responses obtained with encoder sensors are used to identify the servo actuator dynamics.

Multidimensional thermal/chemical modeling is an essential step in the development of a predictive capability for cookoff of energetic materials in systems subjected to abnormal thermal environments. COYOTE II is a state-of-the-art two- and three-dimensional finite element code for the solution of heat conduction problems including surface-to-surface thermal radiation heat transfer and decomposition chemistry. Multistep finite rate chemistry is incorporated into COYOTE II using an operator-splitting methodology; rate equations are solved element-by-element with a modified matrix-free stiff solver, CHEMEQ. COYOTE II is purposely designed with a user-oriented input structure compatible with the database, the pre-processing mesh generation, and the post-processing tools for data visualization shared with other engineering analysis codes available at Sandia National Laboratories. As demonstrated in a companion paper, decomposition during cookoff in a confined or semi-confined system leads to significant mechanical behavior. Although mechanical effect are not presently considered in COYOTE II, the formalism for including mechanics in multidimensions is under development.

The molecular-scale species distributions and intermediate-scale structure of silicate sols influence the microstructures of the corresponding thin films prepared by dip-coating. Using multi-step hydrolysis procedures, the authors find that, depending on the sequence and timing of the successive steps, the species distributions (determined by {sup 29}Si NMR) and intermediate scale structure (determined by SAXS) can change remarkably for sols prepared with the same nominal composition. During film formation, these kinetic effects cause differences in the efficiency of packing of the silicate species, leading to thin film structures with different porosities.

VISAR (Velocity Interferometer System for Any Reflector) is a specialized Doppler interferometer system that is gaining world-wide acceptance as the standard for shock phenomena analysis. The VISAR`s large power and cooling requirements, and the sensitive and complex nature of the interferometer cavity has restricted the traditional system to the laboratory. This paper describes the new portable VISAR, its peripheral sensors, and the role it played in optically measuring ground shock of an underground nuclear detonation (UGT). The Solid State VISAR uses a prototype diode pumped Nd:YAG laser and solid state detectors that provide a suitcase-size system with low power requirements. A special window and sensors was developed for fiber optic coupling (1 kilometer long) to the VISCAR. The system has proven itself as reliable, easy to use instrument that is capable of field test use and rapid data reduction using only a notebook personal computer (PC).

The improvements in purity of molding materials, the IC wafer passivation layers, and manufacturing quality have resulted over the last decade in extremely high reliability in commercial IC packages. In contrast the ceramic/hermetic package world is suffering from limited availability of the newest IC chips, higher cost, larger size, and decreasing quality and fewer manufacturing lines. Traditional manufacturing line qualification tests are a good start for conversion to commercial plastic parts. However, the use of standard sensitive test chips instead of product die is necessary to perform affordable, quantitative evaluations. These test chips have many integrated sensors measuring chemical, mechanical, thermal, and electrical degradation caused by manufacturing and the package environment. Besides visual, electrical test, and burn-in little has been documented on 100% nondestructive screening of plastic molded parts. Based on realistic process control and system engineer cultural expectations, user screening is necessary. Nondestructive tests of moisture and temperature excursion susceptibility are described.

Abstract not provided.

Short communication.

System behaviors can be accurately simulated using artificial neural networks (ANNs), and one that performs well in simulation of structural response is the radial basis function network. A specific implementation of this is the connectionist normalized linear spline (CNLS) network, investigated in this study. A useful framework for ANN simulation of structural response is the recurrent network. This framework simulates the response of a structure one step at a time. It requires as inputs some measures of the excitation, and the response at previous times. On output, the recurrent ANN yields the response at some time in the future. This framework is practical to implement because every ANN requires training, and this is executed by showing the ANN examples of correct input/output behavior (exemplars), and requiring the ANN to simulate this behavior. In practical applications, hundreds or, perhaps, thousands, of exemplars are required for ANN training. The usual laboratory and non-neural numerical applications to be simulated by ANNs produce these amounts of information. Once the recurrent ANN is trained, it can be provided with excitation information, and used to propagate structural response, simulating the response it was trained to approximate. The structural characteristics, parameters in the CNLS network, and degree of training influence the accuracy of approximation. This investigation studies the accuracy of structural response simulation for a single-degree-of-freedom (SDF), nonlinear system excited by random vibration loading. The ANN used to simulate structural response is a recurrent CNLS network. We investigate the error in structural system simulation.

We are improving the understanding of pulsed-power-driven ion diodes using measurements of the charged particle distributions in the diode anode-cathode (AK) gap. We measure the time - and space-resolved electric field in the AK gap using Stark-shifted Li I 2s-2p emission. The ion density in the gap is determined from the electric field profile and the ion current density. The electron density is inferred by subtracting the net charge density, obtained from the derivative of the electric field profile, from the ion density. The measured electric field and charged particle distributions are compared with results from QUICKSILVER, a 3D particle-in-cell computer code. The comparison validates the fundamental concept of electron build-up in the AK gap. However, the PBFA II diode exhibits considerably richer physics than presently contained in the simulation, suggesting improvements both to the experiments and to our understanding of ion diode physics.

The Arrhenius relation predicts a linear relation between log of time to property change and inverse absolute temperature, with the Arrhenius activation energy E{sub a} given from the slope. For a nitrile rubber, Arrhenius behavior is observed for elongation vs air-oven aging temperature, with a E{sub a} of 22 kcal/mol. Confidence in extrapolation to low temperatures can be increased by measuring oxygen consumption. From 95 to 52 C, the E{sub a} for oxygen consumption is identical to that for elongation; however, below 52 C, the E{sub a} for oxygen consumption drops slightly to 18 kcal/mol, indicating that the extrapolation assumption probably overestimates the tensile property lifetime by a factor of about 2 at 23 C.

Prosperity Games are an outgrowth and adaptation of move/countermove and seminar War Games. Prosperity Games are simulations that explore complex issues in a variety of areas including economics, politics, sociology, environment, education and research. These issues can be examined from a variety of perspectives ranging from a global, macroeconomic and geopolitical viewpoint down to the details of customer/supplier/market interactions in specific industries. All Prosperity Games are unique in that both the game format and the player contributions vary from game to game. This report documents the Prosperity Game conducted under the sponsorship of the Electronic Industries Association. Almost all of the players were from the electronics industry. The game explored policy changes that could enhance US competitiveness in the manufacturing of consumer electronics. Four teams simulated a presidentially appointed commission comprised of high-level representatives from government, industry, universities and national laboratories. A single team represented the foreign equivalent of this commission, formed to develop counter strategies for any changes in US policies. The deliberations and recommendations of these teams provide valuable insights as to the views of this industry concerning policy changes, foreign competition, and the development, delivery and commercialization of new technologies.

An assessment of the long term containment capabilities of a possible nuclear waste disposal site requires both an understanding of the hydrogeology of the region under consideration and an assessment of the uncertainties associated with this understanding. Stochastic simulation - the generation of random {open_quotes}realizations{close_quotes} of the regions hydrogeology, consistent with the available information, provides a way to incorporate various types of uncertainty into a prediction of a complex system response such as site containment capability. One statistical problem in stochastic simulation is: What features of the data should be {open_quotes}mimicked{close_quotes} in the realizations? The answer can depend on the application. A discussion is provided of some of the more common data features used in recent applications. These features include spatial covariance functions and measures of the connectivity of extreme values, as examples. Trends and new directions in this area are summarized including a brief description of some statistics (the features) presently in experimental stages.

This report describes the Height of Charge measurement for the Middle Key 4 test conducted at the FCDNA Permanent High Explosives Test Site (PHETS) on 17 September, 1993. The object of the measurement was to monitor remotely the change in the height of the explosive charge suspended above the test pad once the site had been evacuated until detonation. Should the measurement have shown that the charge changed height by more than 15cm then a hold in the test was to be called so that a height adjustment in the suspension system could be made. The measurement system consisted of a remotely placed video camera linked to the test control center-based measurement computer via a fiber optical video data link, a pole mounted stationary reference target, and a target mounted on the charge bag. Measurement of the change in height was determined using image analysis software on frame grabbed images. Measurements indicate that the charge bag did not deviate from the initial surveyed height of 1747cm by more than 1cm between the last measurement made by the survey crew until detonation 40 minutes later.

Vehicle lateral dynamics are affected by vehicle mass, longitudinal velocity, vehicle inertia, and the cornering stiffness of the tires. All of these parameters are subject to variation, even over the course of a single trip. Therefore, a practical lateral control system must guarantee stability, and hopefully ride comfort, over a wide range of parameter changes. This paper describes a robust controller which theoretically guarantees stability over a wide range of parameter changes. The robust controller is designed using a frequency domain transfer function approach. An uncertainty band in the frequency domain is determined using simulations over the range of expected parameter variations. Based on this bound, a robust controller is designed by solving the Nevanlinna-Pick interpolation problem. The performance of the robust controller is then evaluated over the range of parameter variations through simulations.

HEISHI is a Fortran computer model designed to aid in analysis, prediction, and optimization of fuel characteristics for use in Space Nuclear Thermal Propulsion (SNTP). Calculational results include fission product release rate, fuel failure fraction, mode of fuel failure, stress-strain state, and fuel material morphology. HEISHI contains models for decay chain calculations of retained and released fission products, based on an input power history and release coefficients. Decay chain parameters such as direct fission yield, decay rates, and branching fractions are obtained from a database. HEISHI also contains models for stress-strain behavior of multilayered fuel particles with creep and differential thermal expansion effects, transient particle temperature profile, grain growth, and fuel particle failure fraction. Grain growth is treated as a function of temperature; the failure fraction depends on the coating tensile strength, which in turn is a function of grain size. The HEISHI code is intended for use in analysis of coated fuel particles for use in particle bed reactors; however, much of the code is geometry-independent and applicable to fuel geometries other than spherical.

Aging Aircraft NDI Validation Center (AANC) was established by the FAA Technical Center (FAATC) at Sandia National Laboratories in August of 1991. The Validation Center supports the inspection portion of the FAA`s National Aging Aircraft Program which was mandated by Congress in the 1988 Aviation Safety Act. The ultimate customers of the AANC include the FAA, airframe and engine manufacturers, airlines, and third party maintenance facilities. One goal of the AANC is to provide independent validation of technologies intended to enhance the structural inspection of aging commuter and transport aircraft. Another goal is to assist in transferring emerging inspection technology from other parts of the FAA`s program to the aircraft industry. The deliverables from both these activities are an assessment of the reliability and cost benefits of an inspection technology as applied to a particular inspection or class of inspections. The validation process consists of a quantitative and systematic assessment of the reliability and cost/benefits on a Nondestructive Inspection (NDI) process. A NDI process is defined as the NDI systems and procedures used for inspections. This includes the NDI operator, inspection environment, and the object being inspected. The phases of the validation process are: 1. Conceptual, 2. Preliminary design, 3. Final design, and 4. Field implementation. The AAANC usually gets involved in the validation process during Phases 2 and 3. The Center supports field trials with a full array of test specimens and established procedures for conducting the trials. Phase 4 reliability includes field trials using independent inspectors either at the Center`s hangar or at outside maintenance facilities. Three activities are summarized below where inspection technology has been validated in the field. These are: (1) eddy current inspection reliability experiment; (2) magneto optic imager validation; and (3) inspection tool improvement.