Publications

This paper documents an investigation of approaches to improving the quality of Pro/Engineer-created solid model data for use by downstream applications. The investigation identified a number of sources of problems caused by deficiencies in Pro/Engineer`s geometric engine, and developed prototype software capable of detecting many of these problems and guiding users towards simplified, useable models. The prototype software was tested using Sandia production solid models, and provided significant leverage in attacking the simplification problem.

The CONTAIN 2.0 computer code is an integrated analysis tool used for predicting the physical conditions, chemical compositions, and distributions of radiological materials inside a containment building following the release of material from the primary system in a light-water reactor accident. It can also predict the source term to the environment. CONTAIN 2.0 is intended to replace the earlier CONTAIN 1.12, which was released in 1991. The purpose of this Code Manual is to provide full documentation of the features and models in CONTAIN 2.0. Besides complete descriptions of the models, this Code Manual provides a complete description of the input and output from the code. CONTAIN 2.0 is a highly flexible and modular code that can run problems that are either quite simple or highly complex. An important aspect of CONTAIN is that the interactions among thermal-hydraulic phenomena, aerosol behavior, and fission product behavior are taken into account. The code includes atmospheric models for steam/air thermodynamics, intercell flows, condensation/evaporation on structures and aerosols, aerosol behavior, and gas combustion. It also includes models for reactor cavity phenomena such as core-concrete interactions and coolant pool boiling. Heat conduction in structures, fission product decay and transport, radioactive decay heating, and the thermal-hydraulic and fission product decontamination effects of engineered safety features are also modeled. To the extent possible, the best available models for severe accident phenomena have been incorporated into CONTAIN, but it is intrinsic to the nature of accident analysis that significant uncertainty exists regarding numerous phenomena. In those cases, sensitivity studies can be performed with CONTAIN by means of user-specified input parameters. Thus, the code can be viewed as a tool designed to assist the knowledge reactor safety analyst in evaluating the consequences of specific modeling assumptions.

This report provides a summary of the Pulser In a Chip 9000-Discretionary LDRD. The program began in January of 1997 and concluded in September of 1997. The over-arching goal of this LDRD is to study whether laser diode triggered photoconductive semiconductor switches (PCSS) can be used to activate electro-optic devices such as Q-switches and Pockels cells and to study possible laser diode/switch integration. The PCSS switches we used were high gain GaAs switches because they can be triggered with small amounts of laser light. The specific goals of the LDRD were to demonstrate: (1) that small laser diode arrays that are potential candidates for laser-switch integration will indeed trigger the PCSS switch, and (2) that high gain GaAs switches can be used to trigger optical Q-switches in lasers such as the lasers to be used in the X-1 Advanced Radiation Source and the laser used for direct optical initiation (DOI) of explosives. The technology developed with this LDRD is now the prime candidate for triggering the Q switch in the multiple lasers in the laser trigger system of the X-1 Advanced Radiation Source and may be utilized in other accelerators. As part of the LDRD we developed a commercial supplier. To study laser/switch integration we tested triggering the high gain GaAs switches with: edge emitting laser diodes, vertical cavity surface emitting lasers (VCSELs), and transverse junction stripe (TJS) lasers. The first two types of lasers (edge emitting and VCSELs) did activate the PCSS but are harder to integrate with the PCSS for a compact package. The US lasers, while easier to integrate with the switch, did not trigger the PCSS at the US laser power levels we used. The PCSS was used to activate the Q-switch of the compact laser to be used in the X-1 Advanced Radiation Source.

During November/96 to April/97 Sandia National Laboratories provided consulation, data collection, analysis and project documentation to the U.S. Army for a series of four geothermal exploratory slimholes drilled on the McGregor Range approximately 25 miles north of El Paso, Texas. This drilling was directed toward evaluating a potential reservoir for geothermal power generation in this area, with a secondary objective of assessing the potential for direct use applications such as space heating or water de-salinization. This report includes: representative temperature logs from the wells; daily drilling reports; a narrative account of the drilling and testing; a description of equipment used; a summary and preliminary interpretation of the data; and recommendations for future work.

The WCEDS prototype software system was developed to investigate the usefulness of waveform correlation methods for CTBT monitoring. The WCEDS prototype performs global seismic event detection and has been used in numerous experiments. This report documents the software system design, presenting an overview of the system operation, describing the system functions, tracing the information flow through the system, discussing the software structures, and describing the subsystem services and interactions. The effectiveness of the software design in meeting project objectives is considered, as well as opportunities for code refuse and lessons learned from the development process. The report concludes with recommendations for modifications and additions envisioned for regional waveform-correlation-based detector.

This report presents a detailed analysis of the results from fatigue studies of wind turbine blade composite materials carried out at Montana State University (MSU) over the last seven years. It is intended to be used in conjunction with the DOE/MSU composite Materials Fatigue Database. The fatigue testing of composite materials requires the adaptation of standard test methods to the particular composite structure of concern. The stranded fabric E-glass reinforcement used by many blade manufacturers has required the development of several test modifications to obtain valid test data for materials with particular reinforcement details, over the required range of tensile and compressive loadings. Additionally, a novel testing approach to high frequency (100 Hz) testing for high cycle fatigue using minicoupons has been developed and validated. The database for standard coupon tests now includes over 4,100 data points for over 110 materials systems. The report analyzes the database for trends and transitions in static and fatigue behavior with various materials parameters. Parameters explored are reinforcement fabric architecture, fiber content, content of fibers oriented in the load direction, matrix material, and loading parameters (tension, compression, and reversed loading). Significant transitions from good fatigue resistance to poor fatigue resistance are evident in the range of materials currently used in many blades. A preliminary evaluation of knockdowns for selected structural details is also presented. The high frequency database provides a significant set of data for various loading conditions in the longitudinal and transverse directions of unidirectional composites out to 10{sup 8} cycles. The results are expressed in stress and strain based Goodman Diagrams suitable for design. A discussion is provided to guide the user of the database in its application to blade design.

An efficient method is presented for calculation of RMS von Mises stresses from stress component transfer functions and the Fourier representation of random input forces. An efficient implementation of the method calculates the RMS stresses directly from the linear stress and displacement modes. The key relation presented is one suggested in past literature, but does not appear to have been previously exploited in this manner.

This study is the second phase in a combined analytical and experimental effort to characterize and improve the ride quality of the Department of Energy tractor/trailer. The discussion includes a brief overview of the finite element model of the vehicle and experimental road and modal test results. A novel system identification approach is used, employing both lab-based modal tests, and modal data derived using the Natural Excitation Technique (NExT), a scheme that utilizes the roadway surface as a natural forcing function. The use of a cab isolation system is investigated with the computer model for purposes of improving the ride quality of the vehicle. To validate these analytical predictions, an engineering prototype vehicle was developed, which included a cab isolation system, to experimentally assess ride quality. Ride quality improvements due to the addition of the isolation system are then assessed both experimentally and analytically, and the results are compared.

The predictive modeling of vibration of many structural systems is crippled by an inability to predictively model the mechanics of joints. The lack of understanding of joint dynamics is evidenced by the substantial uncertainty of joint compliances in the numerical models and by the complete inability to predict joint damping. The lore is that at low amplitudes, joint mechanics are associated with Coulomb friction and stick-slip phenomena and that at high amplitudes, impact processes result in dissipation as well as shift of energy to other frequencies. Inadequate understanding of the physics precludes reliable predictions. In this introductory work, joint compliance is studied in both a numerical and experimental setting. A simple bolted interface is used as the test article and compliance is measured for the joint in both compression and in tension. This simple interface is shown to exhibit a strong non-linearity near the transition from compression to tension (or vice-versa). Modeling issues pertaining to numerically solving for the compliance are addressed. It is shown that the model predicts the experimental strains and compliance fairly well. It will be seen that the joint behavior is a mechanical analogy to a diode. In compression, the joint is very stiff, acting almost as a rigid link, while in tension the joint is soft, acting as a soft spring. Although there have been many other studies performed on bolted joints, the variety of joint geometries has demonstrated large variations in behavior. This study is an attempt to quantify the behavior of typical joints found in today`s weapon systems.

Cl{sub 2}-based Inductively Coupled Plasmas with low additional dc self- biases(-100V) produce convenient etch rates(500-1500 A /min) for GaN, AlN, InN, InAlN and InGaN. A systematic study of the effects of additive gas(Ar, N{sub 2}, H{sub 2}), discharge composition and ICP source power and chuck power on etch rate and surface morphology has been performed. The general trends are to go through a maximum in etch rate with percent Cl{sub 2} in the discharge for all three mixtures, and to have an increase(decrease) in etch rate with source power(pressure). Since the etching is strongly ion-assisted, anisotropic pattern transfer is readily achieved. Maximum etch selectivities of approximately 6 for InN over the other nitrides were obtained.

This paper describes a modular approach for computing redundant robot kinematics. First some conventional redundant control methods are presented and shown to be `passive control laws`, i.e. they can be represented by a network consisting of passive elements. These networks are then put into modular form by applying scattering operator techniques. Additional subnetwork modules can then be added to further shape the motion. Modules for obstacle detection, joint limit avoidance, proximity sensing, and for imposing nonlinear velocity constraints are presented. The resulting redundant robot control system is modular, flexible and robust.

This paper describes a modeling technique for single-agent reactive systems, that is influenced by the modeling paradigm of Parnas as well as by the synchronous paradigms of LUSTRE and ESTEREL. In this paradigm, single-agent reactive systems are modeled in a universe having a discrete clock. This discretization of time greatly reduces the temporal complexity of the model. According to the author, the advantage of this reduction in temporal complexity is that the resulting model is in many ways better suited to automated software construction and analysis techniques (e.g., deductive synthesis, transformation, and verification) than models that are based on continuous representations of time.

Effective management of DOE`s transportation operations requires better data than are currently available, a more integrated management structure for making transportation decisions, and decision support tools to provide needed analysis capabilities. This paper describes a vision of an advanced logistics management system for DOE, and the rationale for developing improved modeling and simulation capability as an integral part of that system. The authors illustrate useful types of models through four examples, addressing issues of transportation package allocation, fleet sizing, routing/scheduling, and emergency responder location. The overall vision for the advanced logistics management system, and the specific examples of potential capabilities, provide the basis for a conclusion that such a system would meet a critical DOE need in the area of radioactive material and waste transportation.

Sandia was presented with an opportunity in 1993 to design containers for the long term storage and transport of fissile material. This program was undertaken at the direction of the US Department of Energy and in cooperation with Lawrence Livermore National Laboratory and Los Alamos National Laboratory which were tasked with developing the internal fixturing for the contents. The hardware is being supplied by Allied Signal Federal Manufacturing and Technologies, and the packaging will occur at Mason and Hangar Corporation`s Pantex Plant. The unique challenge was to design a container that could be sealed with the fissile material contents; and, anytime during the next 50 years, the container could be transported with only the need for the pre-shipment leak test. This required not only a rigorous design capable of meeting the long term storage and transportation requirements, but also resulted in development of a surveillance program to ensure that the container continues to perform as designed over the 50-year life. This paper addresses the design of the container, the testing that was undertaken to demonstrate compliance with US radioactive materials transport regulations, and the surveillance program that has been initiated to ensure the 50-year performance.

The authors propose a general technique called solution decomposition to devise approximation algorithms with provable performance guarantees. The technique is applicable to a large class of combinatorial optimization problems that can be formulated as integer linear programs. Two key ingredients of the technique involve finding a decomposition of a fractional solution into a convex combination of feasible integral solutions and devising generic approximation algorithms based on calls to such decompositions as oracles. The technique is closely related to randomized rounding. The method yields as corollaries unified solutions to a number of well studied problems and it provides the first approximation algorithms with provable guarantees for a number of new problems. The particular results obtained in this paper include the following: (1) The authors demonstrate how the technique can be used to provide more understanding of previous results and new algorithms for classical problems such as Multicriteria Spanning Trees, and Suitcase Packing. (2) They show how the ideas can be extended to apply to multicriteria optimization problems, in which they wish to minimize a certain objective function subject to one or more budget constraints. As corollaries they obtain first non-trivial multicriteria approximation algorithms for problems including the k-Hurdle and the Network Inhibition problems.

The Waste Isolation Pilot Plant (WIPP) Compliance Certification Application (CCA) Performance Assessment (PA) used a relational database that was originally designed only to supply the input parameters required for implementation of the PA codes. Reviewers used the database as a point of entry to audit quality assurance measures for control, traceability, and retrievability of input information used for analysis, and output/work products. During these audits it became apparent that modifications to the architecture and scope of the database would benefit the EPA regulator and other stakeholders when reviewing the recertification application. This paper contains a discussion of the WPP PA CCA database and lessons learned for designing a database.

When implementing a Quality Assurance (QA) program, compliance and cost must be balanced. A QA program must be developed that hits the mark in terms of adequate control and documentation, but does not unnecessarily expand resources. As the Waste Isolation Pilot Plant (WIPP) has moved towards certification, Sandia National Laboratories has learned much about balancing compliance and costs. Some of these lessons are summarized here.

The Yucca Mountain Project conducted a Single Heater Test (SHT) in the Exploratory Studies Facility at Yucca Mountain. During the nine month-long heating phase, approximately 4 m{sup 3} of in situ, fractured, 92% saturated, welded tuff was heated to temperatures above 100 C by a 5 m long, 3.8 kW, horizontal, line heater. In this paper, the thermal data collected during the test (Sandia National Laboratories, 1997) are compared to three numerical simulations (Sobolik et al., 1996) in order to gain insight into the coupled thermal-hydrologic processes. All three numerical simulations rely on the Equivalent Continuum Model (ECM) for reasons of computational efficiency. The ECM assumes that the matrix and the fractures are in thermodynamic equilibrium which allows the thermal and hydrologic properties of the matrix and the fractures to be combined into single, bulk values. The three numerical simulations differ only in their bulk permeabilities and are referred to as the High, Low and Matrix Permeability Models, respectively. In the Matrix Permeability Model, the system behaves as an unfractured porous medium with the properties of the rock matrix.

Movement of water through fractures plays an important role in performance assessments of the potential high-level nuclear waste repository at Yucca Mountain, Nevada. The magnitude and frequency of water flowing through individual fractures impacts predictions of the near-field environment and waste-package corrosion. Discrete fracture flow paths, referred to as ``weeps``, have been derived from dual continuum models of fracture flow. The required parameters include the geometric fracture spacing, an assumed width of each weep, and a scaling factor that accounts for reduced flow between fracture and matrix elements in dual continuum models. The formulation provides a convenient means to determine discrete weep spacing and flow rates that are mathematically consistent with the dual continuum model. Specific applications and examples related to seepage into drifts are also discussed.

This paper presents simulations of unsaturated groundwater flow and radionuclide transport at Yucca Mountain using the numerical codes TOUGH2 and FEHM. The simulations test the proposed methodology for coupling flow and transport in the upcoming Total Systems Performance Assessment and Viability Assessment (TSPA-VA). The simulations also reveal the sensitivity of transport results to different weighting schemes for hydraulic conductivities used in liquid flux calculations. Results indicate that coupling TOUGH2 and FEHM is a viable method for simulating flow and transport at Yucca Mountain when a modified upstream weighting scheme is used to simulate the flow fields.

The Russian-US joint program on the safety of nuclear materials was initiated in response to the 1993 Tomsk-7 accident. The bases for this program are the common technical issues confronting the US and Russia in the safe management of excess weapons grade nuclear materials. The US and Russian weapons dismantlement process is producing hundreds of tons of excess Pu and HEU fissile materials. The US is on a two path approach for disposition of excess Pu: (1) use Pu in existing reactors and/or (2) immobilize Pu in glass or ceramics followed by geologic disposal. Russian plans are to fuel reactors with excess Pu. US and Russia are both converting and blending HEU into LEU for use in existing reactors. Fissile nuclear materials storage, handling, processing, and transportation will be occurring in both countries for tens of years. A table provides a history of the major events comprising the Russian-US joint program on the safety of nuclear materials. A paper delineating program efforts was delivered at the SPECTRUM '96 conference. This paper provides an update on program activities since then.

Direct metal deposition technologies produce complex, near net shape components from CAD solid models. Most of these techniques fabricate a component by melting powder in a laser weld pool, rastering this weld bead to form a layer, and additively constructing subsequent layers. Powder feed material in these processes results in near net shape, high strength components, with the ability to blend materials for novel properties. This talk will describe a new direct metal deposition process, known as 3DWire, whereby a small diameter wire is used instead of powder as the feed material to fabricate components. This allows for faster deposition rates, smoother surface finishes, and easy material handling. Currently, parts are being fabricated from 308L stainless steel and Aermet{reg_sign} 100. Microscopy studies show the 3DWire parts to be fully dense with fine microstructural features. Initial mechanical tests show stainless steel parts to have good strength values ({sigma}{sub y} = 58 ksi, {sigma}{sub ult} = 95 ksi, 87 HRB) with retained ductility (65%).

This paper presents a model developed for predicting the mechanical response of inelastic media with heterogeneous microstructure. Particular emphasis is given to the development of microstructural damage along grains. The model is developed within the concepts of continuum mechanics, with special emphasis on the development of internal boundaries in the continuum by utilizing fracture mechanics-based cohesive zone models. In addition, the grains are assumed to be characterized by nonlinear viscoplastic material behavior. Implementation of the model to a finite element computational algorithm is also briefly described, and example solutions are obtained. Finally, homogenization procedures are discussed for obtaining macroscopic damage dependent mechanical constitutive equations that may then be utilized to construct a well-posed boundary value problem for the macroscopically homogenized damage dependent medium.

Rigid polyurethane foams are frequently used as encapsulants to isolate and support thermally sensitive components within weapon systems. When exposed to abnormal thermal environments, such as fire, the polyurethane foam decomposes to form products having a wide distribution of molecular weights and can dominate the overall thermal response of the system. Mechanical response of the decomposing foam, such as thermal expansion under various loading conditions created by gas generation, remains a major unsolved problem. A constitutive model of the reactive foam is needed to describe the coupling between mechanical response and chemical decomposition of foam exposed to environments such as fire. Towards this end, a reactive elastic-plastic constitutive model based on bubble mechanics describing nucleation, decomposition chemistry, and elastic/plastic mechanical behavior of rigid polyurethane foam has been developed. A local force balance, with mass continuity constraints, forms the basis of the constitutive model requiring input of temperature and the fraction of the material converted to gas. This constitutive model provides a stress-strain relationship which is applicable for a broad class of reacting materials such as explosives, propellants, pyrotechnics, and decomposing foams. The model is applied to a block of foam exposed to various thermal fluxes. The model is also applied to a sphere of foam confined in brass. The predicted mechanical deformation of the foam block and sphere are shown to qualitatively agree with experimental observations.

Determination of product species, equations-of-state (EOS) and thermochemical properties of high explosives and pyrotechnics remains a major unsolved problem. Although, empirical EOS models may be calibrated to replicate detonation conditions within experimental variability (5--10%), different states, e.g. expansion, may produce significant discrepancy with data if the basic form of the EOS model is incorrect. A more physically realistic EOS model based on intermolecular potentials, such as the Jacobs Cowperthwaite Zwisler (JCZ3) EOS, is needed to predict detonation states as well as expanded states. Predictive capability for any EOS requires a large species data base composed of a wide variety of elements. Unfortunately, only 20 species have known JCZ3 molecular force constants. Of these 20 species, only 10 have been adequately compared to experimental data such as molecular scattering or shock Hugoniot data. Since data in the strongly repulsive region of the molecular potential is limited, alternative methods must be found to deduce force constants for a larger number of species. The objective of the present study is to determine JCZ3 product species force constants by using a corresponding states theory. Intermolecular potential parameters were obtained for a variety of gas species using a simple corresponding states technique with critical volume and critical temperature. A more complex, four parameter corresponding state method with shape and polarity corrections was also used to obtain intermolecular potential parameters. Both corresponding state methods were used to predict shock Hugoniot data obtained from pure liquids. The simple corresponding state method is shown to give adequate agreement with shock Hugoniot data.

Sandia embarked on its first exercise in corporate strategic planning during the winter of 1989. The results of that effort were disseminated with the publication of Strategic Plan 1990. Four years later Sandia conducted their second major planning effort and published Strategic Plan 1994. Sandia`s 1994 planning effort linked very clearly to the Department of Energy`s first strategic plan, Fueling a Competitive Economy. It benefited as well from the leadership of Lockheed Martin Corporation, the management and operating contractor. Lockheed Martin`s corporate success is founded on visionary strategic planning and annual operational planning driven by customer requirements and technology opportunities. In 1996 Sandia conducted another major planning effort that resulted in the development of eight long-term Strategic Objectives. Strategic Plan 1997 differs from its predecessors in that the robust elements of previous efforts have been integrated into one comprehensive body. The changes implemented so far have helped establish a living strategic plan with a stronger business focus and with clear deployment throughout Sandia. The concept of a personal line of sight for all employees to this strategic plan and its objectives, goals, and annual milestones is becoming a reality.

A buckling calculation procedure based on the method of quadratic components is presented. Recently developed for simulating the motion of rotating flexible structures, the method of quadratic components is shown to be applicable to buckling problems with either conservative or nonconservative loads. For conservative loads, stability follows from the positive definiteness of the system`s stiffness matrix. For nonconservative loads, stability is determined by solving a nonsymmetric eigenvalue problem, which depends on both the stiffness and mass distribution of the system. Buckling calculations presented for a cantilevered beam are shown to compare favorably with classical results. Although the example problem is fairly simple and well-understood, the procedure can be used in conjunction with a general-purpose finite element code for buckling calculations of more complex systems.

The Waste Isolation Pilot Plant (WIPP) in southeast New Mexico has been studied as a transuranic waste repository for the past 23 years. During this time, an extensive site characterization, design, construction, and experimental program was completed to provide in-depth understanding of the dominant processes that are most likely to influence the containment of radionuclides for 10,000 years. The success of the program, however, is defined by the regulator in the context of compliance with performance criteria, rather than by the in-depth technical understanding typical of most scientific programs. The WIPP project was successful in making a transformation from science to compliance by refocusing and redirecting programmatic efforts toward the singular goal of meeting regulatory compliance requirements while accelerating the submittal of the Compliance Certification Application (CCA) by two months from the April 1994 Disposal Decision Plan (DDP) date of December 1996, and by reducing projected characterization costs by more than 40%. This experience is unparalleled within the radioactive waste management community and has contributed to numerous lessons learned from which the entire community can benefit.

The Waste Isolation Pilot Plant (WIPP) in southeast New Mexico has been studied as a transuranic waste repository for the past 23 years. During this time, an extensive site characterization, design, construction, and experimental program was completed, which provided in-depth understanding of the dominant processes that are most likely to influence the containment of radionuclides for 10,000 years. Nearly 1,500 parameters were developed using information gathered from this program; the parameters were input to numerical models for WIPP Compliance Certification Application (CCA) Performance Assessment (PA) calculations. The CCA probabilistic codes frequently require input values that define a statistical distribution for each parameter. Developing parameter distributions begins with the assignment of an appropriate distribution type, which is dependent on the type, magnitude, and volume of data or information available. The development of the parameter distribution values may require interpretation or statistical analysis of raw data, combining raw data with literature values, scaling of lab or field data to fit code grid mesh sizes, or other transformation. Parameter development and documentation of the development process were very complicated, especially for those parameters based on empirical data; they required the integration of information from Sandia National Laboratories (SNL) code sponsors, parameter task leaders (PTLs), performance assessment analysts (PAAs), and experimental principal investigators (PIs). This paper, Part 1 of two parts, contains a discussion of the parameter development process, roles and responsibilities, and lessons learned. Part 2 will discuss parameter documentation, traceability and retrievability, and lessons learned from related audits and reviews.

The Waste Isolation Pilot Plant (WIPP) in southeast New Mexico has been studied as a transuranic waste repository for the past 23 years. During this time, an extensive site characterization, design, construction, and experimental program was completed, which provided in depth understanding of the dominant processes that are most likely to influence the containment of radionuclides for 10,000 years. Nearly 1,500 parameters were developed using information gathered from this program and were input to numerical models for WIPP Compliance Certification Application (CCA) Performance Assessment (PA) calculations. The CCA probability models require input parameters that are defined by a statistical distribution. Developing parameters begins with the assignment of an appropriate distribution type, which is dependent on the type, magnitude, and volume of data or information available. Parameter development may require interpretation or statistical analysis of raw data, combining raw data with literature values, scaling laboratory or field data to fit code grid mesh sizes, or other transformations. Documentation of parameter development is designed to answer two questions: What source information was used to develop this parameter? and Why was this particular data set/information used? Therefore, complete documentation requires integrating information from code sponsors, parameter task leaders, performance assessment analysts, and experimental principal investigators. This paper, Part 2 of 2 parts, contains a discussion of the WIPP CCA PA Parameter Tracking System, document traceability and retrievability, and lessons learned from related audits and reviews.

The design of an effective physical protection system (PPS) includes the determination of the PPS objectives, the initial design of a PPS, the evaluation of the design, and probably, the redesign or refinement of the system. To develop the objectives, the designer must begin by gathering information about facility operation and conditions, such as a comprehensive description of the facility, operating conditions, and the physical protection requirements. The designer then needs to define the threat. This involves considering factors about potential adversaries: class of adversary, adversary`s capabilities, and range of adversary`s tactics. Next, the designer should identify targets. Determination of whether or not the materials being protected are attractive targets is based mainly on the ease or difficulty of acquisition and desirability of the material. The designer now knows the objectives of the PPS, that is, ``what to protect against whom.`` The next step is to design the system by determining how best to combine such elements as fences, vaults, sensors and assessment devices, entry control devices, communication devices, procedures, and protective force personnel to meet the objectives of the system. Once a PPS is designed, it must be analyzed and evaluated to ensure it meets the PPS objectives. Evaluation must allow for features working together to ensure protection rather than regarding each feature separately. Due to the complexity of the protection systems, an evaluation usually requires modeling techniques. If any vulnerabilities are found, the initial system must be redesigned to correct the vulnerabilities and a reevaluation conducted. After the system is installed, the threat and system parameters may change with time. If they do, the analysis must be performed periodically to ensure the system objectives are still being met.

A split Hopkinson bar technique has been developed to evaluate the performance of accelerometers that measure large amplitude pulses. An evaluation of this technique has been conducted in the Mechanical Shock Laboratory at Sandia National Laboratories (SNL) to determine its use in the practical calibration of accelerometers. This evaluation consisted of three tasks. First, the quartz crystal was evaluated in a split Hopkinson bar configuration to evaluate the quartz gage`s sensitivity and frequency response at force levels of 18,000, 35,000 and 53,000 N at ambient temperature, {minus}48 C and +74 C. Secondly, the fly away technique was evaluated at shock amplitudes of 50,000, 100,000, 150,000 and 200,000 G (1 G = 9.81 m/s{sup 2}) at ambient temperature, {minus}48 C and +74 C. Lastly, the technique was performed using a NIST calibrated reference accelerometer. Comparisons of accelerations calculated from the quartz gage data and the measured acceleration data have shown very good agreement. Based on this evaluation, the authors expect this split Hopkinson fly away technique to be certified by the SNL Primary Standards Laboratory.

Many dynamical systems tested in the field and the laboratory display significant nonlinear behavior. Accurate characterization of such systems requires modeling in a nonlinear framework. One construct forming a basis for nonlinear modeling is that of the artificial neural network (ANN). However, when system behavior is complex, the amount of data required to perform training can become unreasonable. The authors reduce the complexity of information present in system response measurements using decomposition via canonical variate analysis. They describe a method for decomposing system responses, then modeling the components with ANNs. A numerical example is presented, along with conclusions and recommendations.

Sandia National Laboratories and Tracor Applied Sciences have developed a proof-of-concept Expert System for the automatic detection and diagnosis of several important problems in geothermal drilling. The system is designed to detect loss of circulation, influx, loss of pump efficiency, and sensor problems. Data from flow sensors (including the rolling float meter), the pump stroke counter and other sensors are processed and examined for deviations from expected patterns. The deviations from expected patterns. The deviations are transformed into evidence for a Bayesian Network (a probabilistic reasoning tool), which estimates the probability of each fault. The results are displayed by a Graphical User Interface, which also allows the user to see data related to a specific fault. The prototype was tested on real data, and successfully detected and diagnosed faults.

This paper presents the results of tests performed on a variety of electrochemical microactuators and arrays of these actuators fabricated in the SUMMiT process at the U.S. Department of Energy`s Sandia National Laboratories. These results are intended to aid designers of thermally actuated mechanisms, and they apply to similar actuators made in other polysilicon MEMS processes such as the MUMPS process. Measurements include force and deflection versus input power, maximum operating frequency, effects of long term operation, and ideal actuator and array geometries for different applications` force requirements. Also, different methods of arraying these actuators together are compared. It is found that a method using rotary joints, enabled by the advanced features of the SUMMiT fabrication process, is the most efficient array design. The design and operation of a thermally actuated stepper motor is explained to illustrate a useful application of these arrays.

The response of a system containing an energetic material (EM) to an abnormal thermal environment is termed cookoff. To predict the violence of reaction of confined energetic materials during cookoff requires a description of the relevant physical processes that occur on time scales Ranging from days to submicroseconds. The time-to-ignition can be characterized accurately using heat transfer with chemistry and quasistatic mechanics. After ignition the energetic material deflagrates on a millisecond time scale. During this time the mechanical processes become dynamic. If the confinement survives burning then accelerated deflagration can lead to shock formation and deflagration to detonation transition. The focus of this work is the dynamic combustion regime in the millisecond time domain. Due to the mathematical stiffness of the chemistry equations and the prohibitively fine spatial resolution requirements needed to resolve the structure of the flame, an interface tracking approach is used to propagate the burn front. Demonstrative calculations are presented that illustrate the dynamic interaction of the deflagrating energetic material with its confinement.

A high consequence system is often defined as one in which the potential exists for severe or catastrophic accidents. Familiar examples include nuclear power plants, airline and other mass transportation, dams and reservoirs, and large-scale food processing. Many manufacturing systems also qualify as high consequence systems. Much of the authors` experience with high consequence systems derives from work associated with the surveillance and dismantlement of nuclear weapons for the US Department of Energy. With such operations, there exists a risk of high explosive detonation accompanied by radiological dispersal and, potentially, nuclear detonation. Analysis of major industrial accidents such as Three Mile Island, Chernobyl and Bhopal have revealed that these incidents were not attributable to a single event or direct cause, but were the result of multiple factors that combined to create a condition ripe for an accident. In each case, human error was a critical factor contributing to the accident. Consequently, many authors have emphasized the need for greater appreciation of systematic factors and in particular, human activities. This paper discusses approaches used in hazard analysis of US nuclear weapons operations to assess risk associated with human factors.

The authors report on an integrated program to understand the fundamentals of LiMn{sub 2}O{sub 4} performance as a cathode for lithium ion rechargeable batteries. Specifically, this program is designed to address the effects of doping on the crystal chemistry, lattice constants, and electrochemical performance. The work is being expanded to include studies on LiCoO{sub 2} and LiNiO{sub 2}.

The authors conducted experiments that monitored the response of heated, confined energetic materials in both fixed-volume and fixed-load configurations. They studied a variety of HMX-based materials, looking at the effects of particle size and binders. The {beta}-{delta} phase transition near 170 C led to a more reactive state. Materials that underwent complete transition in the fixed-load experiments (allowed to expand fully to accommodate the 5% volume increase) cooked off faster than those in the fixed-volume configuration.

International relations are often devoted to establishing agreements that define, control, or regulate issues of potential conflict or dispute. These agreements span a full range of national and international issues from human rights to resource allocations and national security. The scope of these agreements can vary from bilateral arrangements to global treaties or control regimes. In many cases, elements of the agreement are monitored to verify compliance or increase confidence among parties that the terms of the agreement are being met. This article outlines options for cooperation on the Korean peninsula that could build confidence and reduce tension. The role of monitoring technology in helping to implement such agreements is also described.

The Federal Aviation Administration`s Airworthiness Assurance NDI Validation Center (AANC) and the Center for Aviation Systems Reliability (CASR) are currently working to develop a liquid penetrant inspection (LPI) system evaluation capability that will support the needs of the penetrant manufacturers, commercial airline industry and the FAA. The main focus of this facility is to support the evaluation of penetrant inspection materials, penetrant systems and to apply resources to support industry needs. This paper discusses efforts to create such a facility and an initial project to produce fatigue crack specimens for evaluation of Type 1 penetrant sensitivities.

One role of the Intelligent Robotics and System Center (ISRC) at Sandia National Laboratories is to address certain aspects of Sandia`s mission to design, manufacture, maintain, and dismantle nuclear weapon components. Hazardous materials, devices, and environments are often involved. Because of shrinking resources, these tasks must be accomplished with a minimum of prototyping, while maintaining high reliability. In this paper, the authors describe simulation, off-line programming/planning, and related tools which are in use, under development, and being researched to solve these problems at the ISRC.

A technique is presented to simultaneously diffuse boron and phosphorus in silicon, and grow an in-situ passivating oxide in a single furnace step. It is shown that limited solid doping sources made from P and B Spin-On Dopant (SOD) films can produce optimal n{sup +} and p{sup +} profiles simultaneously without the deleterious effects of cross doping. A high quality passivating oxide is grown in-situ beneath the thin ({approximately} 60 {angstrom}) diffusion glass, resulting in low J{sub o} values below 100 fA/cm{sup 2} for transparent ({approximately} 100 {Omega}/{open_square}) phosphorus and boron diffusions. For the first time it is shown that impurities present in the boron SOD film can be effectively filtered out by employing separate source wafers, resulting in bulk lifetimes in excess of 1 ms for the sample wafers. The degree of lifetime degradation in the sources is related to the gettering efficiency of boron in silicon. This novel simultaneous diffusion, in-situ oxidation, impurity filtering and gettering technique was successfully used to produce 20.3% Fz, and 19.1% Cz solar cells, in one furnace step.

A survey of US system integrators, charge controller manufacturers, and battery manufacturers was conducted in 1996 to determine market and application trends. This survey was sponsored by the USDOE. Results from 21 system integrators show a 1995 PV battery sales of $4.76 million. Using the survey results, a top down market analysis was conducted with a total predicted US battery market of $34.7 million and a world wide market of US $302 million. The survey also indicated that 71% (of dollars) were spent on VRLA and 29% on flooded lead-acid batteries. Eighty percent of charge controllers were ON-OFF, vs. PWM or constant voltage.

The Department of Energy (DOE) national laboratories have one of the longest and most consistent histories of supercomputer use. The authors summarize the architecture of DOE`s new supercomputers that are being built for the Accelerated Strategic Computing Initiative (ASCI). The authors then argue that in the near future scaled-down versions of these supercomputers with petaflop-per-weekend capabilities could become widely available to hundreds of research and engineering departments. The availability of such computational resources will allow simulation of physical phenomena to become a full-fledged third branch of scientific exploration, along with theory and experimentation. They describe the ASCI and other supercomputer applications at Sandia National Laboratories, and discuss which lessons learned from Sandia`s long history of supercomputing can be applied in this new setting.

Composite doublers are gaining popularity for their ability to repair and reinforce commercial aircraft structures and it is anticipated that the potential cost savings may spur wider use of this technology. But before composite doublers can be accepted by the civil aviation industry, inspection techniques must be developed to verify the integrity of the doubler and the parent material under the doubler. The Federal Aviation Administration Airworthiness Assurance NDI Validation Center (AANC) is currently developing test methods to inspect aircraft structures under composite doublers using low kilovoltage radiography. This paper documents the radiographic techniques developed by the AANC which have been found to give the best contrast of the radiographic image with reduced image distortion.

In this report, a study of wave propagation and damping in a fluid loaded Flexural Plate Wave (FPW) sensor is presented. Previous to this study, it was believed that supersonic radiation was the dominate mechanism of loss in FPW devices. However, because no previous theory had been developed to explain finite length effects, this belief was never challenged. In this paper, it will be shown that the dominate mechanism of damping is not only due to supersonic radiation, but is also due to a fluid/structure resonance arising from finite length effects. The two-dimensional equations of motion for a single port FPW sensor plate are derived and coupled to the equations of motion for a viscous Newtonian fluid. These coupled equations are solved by using a wave number transform approach. This approach captures dynamics due to source terms at infinity. The resulting solution is comprised of terms derived by Wenzel, plus additional terms representing diffracted wave dynamics. The displacement field above the plate is then determined by using the Helmholtz integral equation.

In 1995, Salt River Project (SRP), a public power utility located in Phoenix, Arizona, collaborated with the Electric Power Research Institute (EPRI) and Sandia National Laboratories (Sandia) to initiate a photovoltaic (PV) power system with battery energy storage to match PV output with residential customer peak energy demand periods. The PV power system, a 2.4kW PV array with 25.2kWh of energy storage, was designed and installed by Southwest Technology Development Institute (SWTDI) at an SRP-owned facility, known as the Chandler Research House during August 1995. This paper presents an overview of the system design, operation and performance. 3 refs., 2 figs., 2 tabs.

The Ministry of the Russian Federation for Atomic Energy (MINATOM) and the US Department of Energy (DOE) are engaged in joint, cooperative efforts to reduce the likelihood of nuclear proliferation by enhancing Material Protection, Control and Accounting (MPC&A) systems in both countries. Mayak Production Association (MPA) is a major Russian nuclear enterprise within the nuclear complex that is operated by MINATOM. This paper describes the nature, scope, and status of the joint, cooperative efforts to enhance existing MPC&A systems at MPA. Current cooperative efforts are focused on enhancements to the existing MPC&A systems at four plants that are operated by MPA and that produce, process, handle and/or store proliferation-sensitive nuclear materials.

PV hybrid electric power systems can offer an economically competitive alternative to engine generator (genset) systems in many off-grid applications. Besides the obvious `green` advantages of producing less noise and emissions, the PV hybrid can, in some cases, offer a lower life-cycle cost (LCC) then the genset. This paper evaluates the LCC of the 9.6 kWp PV hybrid power system installed by the National Park Services (NPS) at Pinnacles National Monument, CA. NPS motivation for installation of this hybrid was not based on economics, but rather the need to replace two aging diesel gensets with an alternative that would be quieter, fuel efficient, and more in keeping with new NPS emphasis on sustainable design and operations. In fact, economic analysis shows a lower 20-year LCC for the installed PV hybrid than for simple replacement of the two gensets. The analysis projects are net savings by the PV hybrid system of $83,561 and over 162,000 gallons of propane when compared with the genset-only system. This net savings is independent of the costs associated with environmental emissions. The effects of including emissions costs, according to NPS guidelines, is also discussed. 5 refs., 2 figs., 3 tabs.