Publications

The electronics industry has relied heavily upon the use of soldering for both package construction and circuit assembly. The solder attachment of devices onto printed circuit boards and ceramic microcircuits has supported the high volume manufacturing processes responsible for low cost, high quality consumer products and military hardware. Defects incurred during the manufacturing process are minimized by the proper selection of solder alloys, substrate materials and process parameters. Prototyping efforts are then used to evaluate the manufacturability of the chosen material systems. Once manufacturing feasibility has been established, service reliability of the final product is evaluated through accelerated testing procedures.

To deliver high bandwidth, a ubiquitous inter-/intra-building cable plant consisting of single mode and multimode fiber as well as twisted pair copper is required. The selection of the ``glue`` to transport and interconnect distributed LANs with central facility resources over a pervasive cable plant is the focus of this paper. A description of the traditional problems that must be overcome to provide very high bandwidth beyond the narrow confines of a computer center is given. The applicability of Asynchronous Transfer Mode (ATM) switching (interconnection) and Synchronous Optical NETwork (SONET) (transport) for high bandwidth delivery is described using the environment and requirements of Sandia National Laboratories. Other methods for distributing high data rates are compared and contrasted. Sandia is implementing a standards based foundation utilizing a pervasive single mode fiber cable plant, SONET transport, and ATM switching to meet the goals of gigabit networking.

The intent of this report is to examine the performance of the Deployable Seismic Verification System (DSVS) developed by the Department of Energy (DOE) through its national laboratories to support monitoring of underground nuclear test treaties. A DSVS was installed at the Pinedale Seismic Research Facility (PSRF) near Boulder, Wyoming during 1991 and 1992. This includes a description of the system and the deployment site. System performance was studied by looking at four areas: system noise, seismic response, state of health (SOH) and operational capabilities.

The three papers in this report were presented at the second international workshop to feature the Waste Isolation Pilot Plant (WIPP) Materials Interface Interactions Test (MIIT). This Workshop on In Situ Tests on Radioactive Waste Forms and Engineered Barriers was held in Corsendonk, Belgium, on October 13--16, 1992, and was sponsored by the Commission of the European Communities (CEC). The Studiecentrum voor Kernenergie/Centre D`Energie Nucleaire (SCK/CEN, Belgium), and the US Department of Energy (via Savannah River) also cosponsored this workshop. Workshop participants from Belgium, France, Germany, Sweden, and the United States gathered to discuss the status, results and overviews of the MIIT program. Nine of the twenty-five total workshop papers were presented on the status and results from the WIPP MIIT program after the five-year in situ conclusion of the program. The total number of published MIIT papers is now up to almost forty. Posttest laboratory analyses are still in progress at multiple participating laboratories. The first MIIT paper in this document, by Wicks and Molecke, provides an overview of the entire test program and focuses on the waste form samples. The second paper, by Molecke and Wicks, concentrates on technical details and repository relevant observations on the in situ conduct, sampling, and termination operations of the MIIT. The third paper, by Sorensen and Molecke, presents and summarizes the available laboratory, posttest corrosion data and results for all of the candidate waste container or overpack metal specimens included in the MIIT program.

This paper is an introductory discussion of stress pulse phenomena in simple solids and fluids. Stress pulse phenomena is a very rich and complex field that has been studied by many scientists and engineers. This paper describes the behavior of stress pulses in idealized materials. Inviscid fluids and simple solids are realistic enough to illustrate the basic behavior of stress pulses. Sections 2 through 8 deal with the behavior of pressure pulses. Pressure is best thought of as the average stress at a point. Section 9 deals with shear stresses which are most important in studying solids.

Sandia National Laboratories, New Mexico, conducts the Utility Battery Storage Systems Program, which is sponsored by the US Department of Energy`s Office of Energy Management. As a part of this program, four utility-specific systems studies were conducted to identify potential battery energy storage applications within each utility network and estimate the related benefits. This report contains the results of these systems studies.

Solid state silicon-29 nuclear magnetic resonance (NMR) spectroscopy has been used to characterize the formation of high pressure silica polymorphs and amorphous material associated with the shocked Coconino Sandstone from Meteor Crater, Arizona. Five samples of the sandstone were obtained from several locations at the crater to represent a range of shock conditions associated with the hypervelocity impact of a 30 m-diameter meteorite. The NMR spectra for these powdered materials exhibit peaks assigned to quartz, coesite, stishovite, and glass. A new resonance in two of the moderately shocked samples is also observed. This resonance has been identified as a densified form of amorphous silica with silicon in tetrahedra with one hydroxyl group. Such a phase is evidence for a shock-induced reaction between quartz and steam under high pressure conditions.

Sandia has developed an advanced operational control system approach, called Graphical Programming, to design and operate robot systems in unstructured environments. This Graphical Programming approach produces robot systems that are faster to develop and use, safer in operation, and cheaper overall than altemative teleoperation or autonomous robot control systems. This approach uses 3-D visualization and simulation software with intuitive operator interfaces for the programming and control of complex robotic systems. Supervisor software modules allow an operator to command and simulate complex tasks in a graphic preview mode and, when acceptable, command the actual robots and monitor their motions with the graphic system. Graphical Programming Supervisors maintain registration with the real world and allow the robot to perform tasks that cannot be accurately represented with models alone by using a combination of model and sensor-based control. All of these capabilities when combined result in a flexible system which is readily able to meet the demands called for in construction automation. This paper describes the Graphical Programming approach, several example control systems that use Graphical Programming, key features necessary for implementing successful Graphical Programming systems, and specific examples of applying these systems to robotic operations.

High spatial resoslution x-ray microanalysis in the analytical electron microscope (AEM) can be used to determine chemical composition on spatial scales of < 50 nm. Simple scattering models have the drawback of being incapable of treating electron scattering in inhomogeneous specimens, such as at phase interfaces or grain boundary segregation. The best method for calculating electron scattering and x-ray generation function is by Mone Carlo methods. Two examples are discussed: a phase interface in an Fe-Ni-Cr alloy, and grain boundary segregation using a 0.3 nm Cu slab in a 25 nm Al film (the slab is parallel to incident electron beam). It is concluded that high spatial resolution x-ray microanalysis can achieve near atomic resolution, but that massively parallel Monte Carlo models for electron scattering and a well characterized electron beam are needed.

Under a Cooperative Agreement between the Commission of European Communities (CEC) and the U. S. Department of Energy (DOE), the Joint Research Centre, (JRC) ISPRA, and Sandia National Laboratories (SNL) have been cooperating in the development of Containment and Surveillance equipment for a number of years. With recent technology advancements, this cooperation is expanding into the areas of Data Authentication, Safeguards Data Networks, Integrated Systems, and Image Processing. This paper will describe recently expanded efforts in connecting the Integrated Monitoring System designed by SNL to the Computer Aided Video Surveillance System designed by JRC. An SNL Modular Video Authentication System was furnished to test in the video circuitry of the Computer Aided Video Surveillance System. The two systems will remain at JRC for demonstrations, training, and future development activities.

Effective application of pan-tilt cameras in alarm assessment systems requires that the overall system design be such that any threat for which the system is designed will be within the field of view of the camera for a sufficiently long time for the assessment of the alarm to be performed. The assessment of alarms in large, unobstructed areas requires a different type of analysis than traditionally used for clear zones between fences along fixed perimeters where an intruder`s possible location is well defined. This paper presents a design methodology which integrates the threat characteristics, sensor detection pattern, system response time, and optics geometry considerations to identify all feasible locations for camera placement for effective assessment of large, unobstructed areas. The methodology also can be used to evaluate tradeoffs among these various considerations to improve candidate designs.

In this study we have developed the techniques to investigate the hydrodynamic response of high-strength ceramics by mixing these powders with copper powder, preparing compacts, and performing shock compression tests on these mixtures. Hydrodynamics properties of silicon carbide, titanium diboride, and boron carbide to 30 GPa were examined by this method, and hydrodynamic compression data for these ceramics have been determined. We have concluded, however, that the measurement method is sensitive to sample preparation and uncertainties in shock wave measurements. Application of the experimental technique is difficult and further efforts are needed.

Developments are reported in both experimental and numerical capabilities for characterizing the debris spray produced in penetration events. We have performed a series of high-velocity experiments specifically designed to examine the fragmentation of the projectile during impact. High-strength, well-characterized steel spheres (6.35 mm diameter) were launched with a two-stage light-gas gun to velocities in the range of 3 to 5 km/s. Normal impact with PMMA plates, thicknesses of 0.6 to 11 mm, applied impulsive loads of various amplitudes and durations to the steel sphere. Multiple flash radiography diagnostics and recovery techniques were used to assess size, velocity, trajectory and statistics of the impact-induced fragment debris. Damage modes to the primary target plate (plastic) and to a secondary target plate (aluminum) were also evaluated. Dynamic fragmentation theories, based on energy-balance principles, were used to evaluate local material deformation and fracture state information from CTH, a three-dimensional Eulerian solid dynamics shock wave propagation code. The local fragment characterization of the material defines a weighted fragment size distribution, and the sum of these distributions provides a composite particle size distribution for the steel sphere. The calculated axial and radial velocity changes agree well with experimental data, and the calculated fragment sizes are in qualitative agreement with the radiographic data. A secondary effort involved the experimental and computational analyses of normal and oblique copper ball impacts on steel target plates. High-resolution radiography and witness plate diagnostics provided impact motion and statistical fragment size data. CTH simulations were performed to test computational models and numerical methods.

Today`s integrated circuits are so complex that it is often necessary to have access to the layouts and schematics when performing voltage contrast, cross sectioning, light emission, mechanical probing, optical beam induced current, and even simple SEM and Optical Examination. To deal with these issues, Sandia National Laboratories is developing an advanced failure analysis laboratory networking scheme to provide computer control, layout navigation, schematic navigation, and report generation on each of the major pieces of failure analysis equipment. This concept is known as an Integrated Diagnostic Environment or IDE. An integrated diagnostic environment is an environment where failure analysis equipment is computer-controlled and linked by a high speed network. The network allows CAD databases to be shared between instruments, improving the failure analyst`s productivity on each analysis task. At Sandia, we are implementing this concept using SUN Sparcstation computers running Schlumberger`s IDE software. To date, we have incorporated our electron beam prober and light emission system into the environment. We will soon add our scanning optical microscope and focused ion beam system and eventually add our optical microscope and microprobe station into the network. There are a number of issues to consider when implementing an Integrated Diagnostic Environment; these are discussed in detail in this paper.

This paper describes the development and use of the Multi-Axis Seam racking (MAST) sensor for tracking seams or other features in real-time. Four independent, spatially-distributed electric fields are used to sense changes in the relative position of the sensor and the workpiece. The MAST sensor is very inexpensive compared with commercially available seam tracking sensors. It can be used in systems to perform cost-effective small-lot manufacturing operations in a faster, more consistent manner. The MAST sensor is used in an automated system for dispensing braze paste during a rocket nozzle fabrication process.

Short communication.

The ability for a communications network to realize arbitrary communications patterns can be expensive both in terms of hardware and in terms of system software. One might instead ask whether a system can be built which performs well for a given application program. In this paper we look at the question of when a set of communications patterns is suitable for fast realization on a given network. In particular we look at which patterns are realizable quickly on a mesh. Contrary to common wisdom, transpose is efficiently realizable on a mesh. However, some other important patterns such as shuffle are not.

The Milling Assistant (MA) programming system demonstrates the automated development of tool paths for Numerical Control (NC) machine tools. By integrating a Case-Based Reasoning decision processor with a commercial CAD/CAM software, intelligent tool path files for milled and point-to-point features can be created. The operational system is capable of reducing the time required to program a variety of parts and improving product quality by collecting and utilizing ``best of practice`` machining strategies.

The US Department of Energy (DOE) is sponsoring the Utility Battery Storage Systems Program at Sandia National Laboratories and its contractors. This program is specifically aimed at developing battery energy storage systems for electric utility applications commencing in the mid to late 1990s. One factory-integrated utility battery system and three battery technologies: sodium/sulfur, zinc/bromine, and lead-acid are being developed under this program. In the last few years the emphasis of this program has focused on battery system development. This emphasis has included greater interactions with utilities to define application requirements. Recent activities have identified specific applications of battery energy storage in certain utility systems and quantified the value of these applications to these utility companies. In part due to these activities, battery energy storage is no longer regarded by utilities as a load-leveling resource only, but as a multifunction, energy management resource.

The US Department of Energy is sponsoring the development of battery energy storage systems for electric utilities. An important part of this DOE program is the engineering of the battery subsystem. Because lower costs are possible and less space is required compared with conventional battery technologies, two advanced battery systems are being developed: sodium/sulfur and zinc/bromine. A brief description of the development approach being followed along with the current status of the sodium/sulfur technology is described in this paper. Of immediate relevance, a factory integrated modular sodium/sulfur system has been designed that incorporates many of the advantages of this technology. Each module (designated as NAS-P{sub AC}) combines a 600-kWh sodium/sulfur battery, a 300 kW power converter and a control system. In addition to the potential for low life-cycle cost, other specific benefits include excellent portability and an installed system-level footprint that is about 20% of an equivalent system using lead-acid batteries. The sodium/sulfur battery is designed to deliver its rated energy for 1500 cycles or 5 years of maintenance-free operation.

Sandia National Laboratories determined that the most effective method to address records management initiatives would be through a single, comprehensive facilities wide records inventory and retention schedule project. The logistic of such an undertaking (estimated at 425,000 linear feet) are demanding. The relatively short time frame required for completion and the project`s size called for sound, up front planning by Sandia and ultimately the support of an outside contractor for qualified resources to execute the plan.

Development of a high-temperature, superconducting, synchronous motor for large applications (>1000 HP) could offer significant electrical power savings for industrial users. Presently 60% of all electric power generated in the United States is converted by electric motors. A large part of two power is utilized by motors 1000 HP or larger. The use of high-temperature superconducting materials with critical temperatures above that of liquid nitrogen (77 K) in the field winding would reduce the losses in these motors significantly, and therefore, would have a definite impact on the electrical power usage in the US. These motors will be 1/3 to 1/2 the size of conventional motors of similar power and, thus, offer potential savings in materials and floor space. The cooling of the superconducting materials in the field windings of the rotor presents a unique application of cryogenic engineering. The rotational velocity results in significant radial pressure gradients that affect the flow distribution of the cryogen. The internal pressure fields can result in significant nonuniformities in the two-phase flow of the coolant. Due to the variable speed design, the flow distribution has the potential to change during operation. A multiphase-flow computer model of the cryogenic cooling is developed to calculate the boiling heat transfer and phase distribution of the nitrogen coolant in the motor. The model accounts for unequal phase velocities and nonuniform cooling requirements of the rotor. The unequal radial pressure gradients in the inlet and outlet headers result in a larger driving force for flow in the outer cooling channels. The effect of this must be accounted for in the design of the motor. Continuing improvements of the model will allow the investigation of the transient thermal issues associated with localized quenching of the superconducting components of the motor.

The deliverability of a reservoir depends primarily on its permeability, which, in many reservoirs, is controlled by a combination of natural fractures and the in situ stresses. Therefore it is important to be able to predict which parts of a basin are most likely to contain naturally fractured strata, what the characteristics of those fractures might be, and what the most likely in situ stresses are at a given location. This paper presents a set of geologic criteria that can be superimposed onto factors, such as levels of maturation and porosity development, in order to predict whether fractures are present once the likelihood of petroleum presence and reservoir development have been determined. Stress causes fracturing, but stresses are not permanent. A natural-fracture permeability pathway opened by one system of stresses may be held open by those stresses, or narrowed or even closed by changes of the stress to an oblique or normal orientation. The origin of stresses and stress anisotropies in a basin, the potential for stress to create natural fractures, and the causes of stress reorientation are examined in this paper. The appendices to this paper present specific techniques for exploiting and characterizing natural fractures, for measuring the present-day in situ stresses, and for reconstructing a computerized stress history for a basin.

By extracting and analyzing measurement (variables) data from portal metal detectors whenever possible instead of the more typical ``alarm``/``no-alarm`` (attributes or binomial) data, we can be more informed about metal detector health with fewer tests. This testing methodology discussed in this report is an alternative to the typical binomial testing and in many ways is far superior.

Varistor material is currently supplied by a single commercial source. The chem-prep varistor process was developed as a backup/replacement. With the transfer of the process to the production facility, studies were made to verify that the process is stable in manufacturing. Process variables are the precursors oxalic acid, NaOH, and ZnCl{sub 2}. Process stability was determined by comparing assay uncertainty region with precipitant/ZnCl{sub 2} compositional region meeting electrical and physical property specifications. Assay variability was assessed by conducting a round robin; standard deviations of repeated assays of the same sample was 0.1 wt% by the same labs; 0.1-0.4 wt% among laboratories. A mixture experiment was then conducted to assess the effects of the precipitants/ZnCl{sub 2} on breakdown field, nonlinearity coefficient, and bulk density. Results indicate that the chem-prep process can be stable; however the nominal target composition was on the edge of the composition region, and it was moved to the center of the large region with acceptable electrical and physical properties. Tests of unpotted component rods made from the new composition met all specifications. 8 refs, 10 figs, 10 tabs.

A summary is presented of the results of a number of studies conducted prior to March 1992 that have led to a conceptual model describing how the porosity (and therefore the permeability) of waste and backfill in a Waste Isolation Pilot Plant disposal room changes with time and also describes how results from calculations involving mathematical models of these processes are used to provide input into performance assessment of the repository. Included in the report are descriptions of essential material response or constitutive models that include the influence of gas generation and the response of simple gas-pressurized cracks and fractures in salt, marker beds, and clay seams. Two-dimensional versus three-dimensional disposal room configurations and descriptions of the differences between numerical codes are also discussed. Calculational results using the mathematical models for disposal room response are described, beginning with closure of empty rooms and becoming progressively more complex. More recent results address some of the effects of gas generation in a room containing waste and backfill and intersected by a gas permeable marker bed. Developments currently in progress to improve the evaluation of the disposal room performance are addressing the coupling between brine flow and closure and the two-dimensional capability for analyzing a complete panel of rooms. Next, a method is described for including disposal room closure results into performance assessment analyses that determine if the repository is in compliance with regulatory standards. The coupling is accomplished using closure surfaces that describe the relationship among porosity, total amount of gas in the repository, and time. A number of conclusions about room response and recommendations for further work are included throughout the report.

The transverse motion of a projectile in an electromagnetic induction launcher is considered. The equations of motion for translation and rotation are derived assuming a rigid projectile and a flyway restoring force per unit length that is proportional to the local displacement. Transverse forces and torques due to energized coils are derived for displaced or tilted projectile elements based on a first order perturbation method. The resulting equations of motion for a rigid projectile composed of multiple elements in a multi-coil launcher are analyzed as a coupled oscillator system of equations and a simple stability condition is derived. The equations of motion are incorporated into the 2-D Slingshot code and numerical solutions for the transverse motion are obtained. For the 20 meter navy launcher parameters we find that stability is achieved with a flyway spring constant of k {approx} 1{times} 10{sup 8} N/m{sup 2}. For k {approx} 1.5 {times} 10{sup 8} N/m{sup 2} and sample coil misalignment modeled as a sine wave of I mm amplitude at wavelengths of one or two meters, the projectile displacement grows to a maximum of 4 mm. This growth is due to resonance between the natural frequency of the Projectile transverse motion and the coil displacement wavelength. This resonance does not persist because of the changing axial velocity. Random coil displacement is also found to cause roughly the same projectile displacement. For the maximum displacement a rough estimate of the transverse pressure is 50 bars.

Uncertainty and sensitivity analysis techniques based on Latin hypercube sampling, partial correlation analysis, stepwise regression analysis and examination of scatterplots are used in conjunction with the BRAGFLO model to examine two phase flow (i.e., gas and brine) at the Waste Isolation Pilot Plant (WIPP), which is being developed by the US Department of Energy as a disposal facility for transuranic waste. The analyses consider either a single waste panel or the entire repository in conjunction with the following cases: (1) fully consolidated shaft, (2) system of shaft seals with panel seals, and (3) single shaft seal without panel seals. The purpose of this analysis is to develop insights on factors that are potentially important in showing compliance with applicable regulations of the US Environmental Protection Agency (i.e., 40 CFR 191, Subpart B; 40 CFR 268). The primary topics investigated are (1) gas production due to corrosion of steel, (2) gas production due to microbial degradation of cellulosics, (3) gas migration into anhydrite marker beds in the Salado Formation, (4) gas migration through a system of shaft seals to overlying strata, and (5) gas migration through a single shaft seal to overlying strata. Important variables identified in the analyses include initial brine saturation of the waste, stoichiometric terms for corrosion of steel and microbial degradation of cellulosics, gas barrier pressure in the anhydrite marker beds, shaft seal permeability, and panel seal permeability.

Satellite servicing is in many ways analogous to subsea robotic servicing in the late 1970`s. A cost effective, reliable, telerobotic capability had to be demonstrated before the oil companies invested money in deep water robot serviceable production facilities. In the same sense, aeronautic engineers will not design satellites for telerobotic servicing until such a quantifiable capability has been demonstrated. New space servicing systems will be markedly different than existing space robot systems. Past space manipulator systems, including the Space Shuttle`s robot arm, have used master/slave technologies with poor fidelity, slow operating speeds and most importantly, in-orbit human operators. In contrast, new systems will be capable of precision operations, conducted at higher rates of speed, and be commanded via ground-control communication links. Challenges presented by this environment include achieving a mandated level of robustness and dependability, radiation hardening, minimum weight and power consumption, and a system which accommodates the inherent communication delay between the ground station and the satellite. There is also a need for a user interface which is easy to use, ensures collision free motions, and is capable of adjusting to an unknown workcell (for repair operations the condition of the satellite may not be known in advance). This paper describes the novel technologies required to deliver such a capability.

A numerical method to simulate viscous diffusion of vorticity using vortex blobs (i.e., without a grid) is presented. The method consists of casting the effects of viscous diffusion into an effective ``diffusion velocity`` at which vortex blobs convect. The diffusion velocity was proposed previously by Ogami and Akamatsu, but they did not consider the effects of the divergence of the diffusion velocity. In fact, the diffusion velocity is highly non-solenoidal, which significantly affects the area over which a vortex blob diffuses. A formulation is presented that relates the area expansion to the diffusion velocity divergence. By taking into account the area expansion, more accurate simulations of diffusion are obtained, as demonstrated by a comparison of numerical and analytical diffusion solutions. Results from simulations show that vortex areas expand significantly in regions of large vorticity gradients. As a result of the area expansion, adjacent vortices remain overlapped, thereby maintaining smooth solution fields. The non-solenoidal diffusion velocity method is easily implemented in vortex blob algorithms, thus facilitating the development of vortex methods to simulate flows with finite Reynolds numbers.

Designed experiments were employed to characterize a process for etching phosphorus doped polycrystalline silicon with HBr in a close-coupled ECR plasma reactor configured for 200 mm wafers. A fractional factorial screening experiment was employed to determine the principal input factors and the main etch effects. Linear models of the process responses indicate RF power, O{sub 2} flow rate, and the position of the resonance zone (with respect to the wafer) as the three strongest factors influencing process performance. Response surfaces generated using data from a follow-on response surface methodology (RSM) experiment predicted an optimum operating region characterized by relatively low RF power, a small O{sub 2} flow, and a resonance zone position close to the wafer. The optimized process demonstrated a polysilicon etch rate of 270 nm/min, an etch rate non-uniformity of 2.2% (1s), an etch selectivity to oxide greater than 100:1, and anisotropic profiles. Particle test results for the optimized process indicated that careful selection of the O{sub 2} fraction is required to avoid polymer deposition and particle formation.

Before disposing of transuranic radioactive waste in the Waste Isolation Pilot Plant (WIPP), the United States Department of Energy (DOE) must evaluate compliance with applicable long-term regulations of the United States Environmental Protection Agency (EPA). Sandia National Laboratories is conducting iterative performance assessments (PAs) of the WIPP for the DOE to provide interim guidance while preparing for a final compliance evaluation. This volume of the 1992 PA contains results of uncertainty and sensitivity analyses with respect to migration of gas and brine from the undisturbed repository. Additional information about the 1992 PA is provided in other volumes. Volume 1 contains an overview of WIPP PA and results of a preliminary comparison with 40 CFR 191, Subpart B. Volume 2 describes the technical basis for the performance assessment, including descriptions of the linked computational models used in the Monte Carlo analyses. Volume 3 contains the reference data base and values for input parameters used in consequence and probability modeling. Volume 4 contains uncertainty and sensitivity analyses with respect to the EPA`s Environmental Standards for the Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Radioactive Wastes (40 CFR 191, Subpart B). Finally, guidance derived from the entire 1992 PA is presented in Volume 6. Results of the 1992 uncertainty and sensitivity analyses indicate that, conditional on the modeling assumptions and the assigned parameter-value distributions, the most important parameters for which uncertainty has the potential to affect gas and brine migration from the undisturbed repository are: initial liquid saturation in the waste, anhydrite permeability, biodegradation-reaction stoichiometry, gas-generation rates for both corrosion and biodegradation under inundated conditions, and the permeability of the long-term shaft seal.

Experiment results are presented for unconfined compressive strength and elastic moduli of tuffaceous rocks from Busted Butte near Yucca Mountain, Nevada. The data have been compiled for the Yucca Mountain Site Characterization Project Site and Engineering Properties Data Base. Experiments were conducted on water-saturated specimens of the potential nuclear waste repository horizon Topopah Spring Member tuff (thermal/mechanical unit TSw2). The influence of strain rate on mechanical properties of the tuff was examined by loading six specimens in uniaxial compression at a strain rate of 10{sup {minus}9} s{sup {minus}1}. The experiments performed under ambient pressure and temperature conditions and conformed to Technical Procedure 91, titled ``Unconfined Compression Experiments at 22{degrees}C and a Strain Rate of 10{sup {minus}9} s{sup {minus}1}.`` The mean and standard deviation values of ultimate strength, Young`s modulus and Poisson`s ratio determined from these experiments are 85.4{plus_minus}21.7 MPa, 33.9{plus_minus}4.6 GPa, and 0.09{plus_minus}0.07, respectively.

Thermomechanical models are being developed to support the design of an Exploratory Studies Facility (ESF) and a potential high-level nuclear waste repository at Yucca Mountain, Nevada. These models are used for preclosure design of underground openings, such as access drifts, emplacement drifts, and waste emplacement boreholes; and in support of postclosure issue resolution relating to waste canister performance, disturbance of the hydrological properties of the host rock, and overall system performance assessment. For both design and performance assessment, the purpose of using models in analyses is to better understand and quantify some phenomenon or process. Therefore, validation is an important process that must be pursued in conjunction with the development and application of models. The Site Characterization Plan (SCP) addressed some general aspects of model validation, but no specific approach has, as yet, been developed for either design or performance assessment models. This paper will discuss a proposed process for thermomechanical model validation and will focus on the use of laboratory and in situ experiments as part of the validation process. The process may be generic enough in nature that it could be applied to the validation of other types of models, for example, models of unsaturated hydrologic flow.

Basaltic volcanism has been identified as a possible future event initiating a release of radionuclides from a potential repository at the proposed Yucca Mountain high-level waste repository site. The performance assessment method set forth in the Site Characterization Plan (DOE, 1988) requires that a set of scenarios encompassing all significant radionuclide release paths to the accessible environment be described. This report attempts to catalogue the details of the interactions between the features and processes produced by basaltic volcanism in the presence of the presumed groundwater flow system and a repository structure, the engineered barrier system (EBS), and waste. This catalogue is developed in the form of scenarios. We define a scenario as a well-posed problem, starting from an initiating event or process and proceeding through a logically connected and physically possible combination or sequence of features, events, and processes (FEPs) to the release of contaminants.

Sandia National Laboratories—a Department of Energy multiprogram national laboratory—has for over four decades applied its talents, tools, and techniques to solving technological problems of national scale. This publication provides information of interest about Sandia National Laboratories and the work being done there.

Commercial applications for advanced rechargeable batteries are constantly increasing. These applications include electric vehicles, large scale energy storage at electric utilities, storage of electrical energy produced by renewable energy resources such as solar or wind generators, and consumer electronics. Commercially available batteries are not able to meet the performance and/or cost requirements of many of these applications. To be successful, advanced battery technology need different combinations of high energy and power densities, long life, low cost, and little or no maintenance. In addition. completely safe operation must be assured.

There are many remote applications which require the dexterous manipulation of tools and materials in the field. These tasks range from the assembly and maintenance of space structures to the characterization and retrieval of hazardous materials here on Earth. Operations which involve the dexterous manipulation of hazardous materials in the field have, in the past, been completed by technicians. Use of humans in such hazardous operations is under increased scrutiny due to high costs and low productivity associated with providing protective clothing and environments. Traditional remote manual field operations have, unfortunately, proven to have very low productivity when compared with unencumbered human operators. Recent advances in the integration of sensors and computing into the control of remotely operated equipment have shown great promise for reducing the cost of remote systems while providing faster and safer remote systems. This paper discusses applications of such advances to remote field operations.

The Facilities Organization at Sandia has undergone many changes in the past five years. Management has made a commitment to improve the matrix management system and apply quality principles to the organization. This management commitment enabled Facilities to use project management tools for defining and documenting Facilities key processes. The resulting documentation included implementation plans for defining participant roles and responsibilities, identifying critical success factors, measuring performance, and ensuring continuous improvement. All of this resulted in benefits that demonstrate the value of project management and show how project management and quality are intertwined.

Centrifugally-cast concrete liners applied to the interiors of plain steel pipe sections were tested for corrosion performance in brine solutions. An American Petroleum Institute (API) standard concrete, with and without additions of a styrene-butadiene copolymer latex, was subjected to simulated service and laboratory tests. Simulated service tests used a mechanically pumped test manifold containing sections of concrete-lined pipe. Linear polarization probes embedded at steel-concrete interfaces tracked corrosion rates of these samples as a function of exposure time. Laboratory tests used electrochemical impedance spectroscopy to study corrosion occurring at the steel-concrete interfaces. Electron probe microanalysis (EPMA) determined ingress and distribution of damaging species, such as Cl, in concrete liners periodically returned from the field. Observations of concrete-liner fabrication indicate that latex loading levels were difficult to control in the centrifugal-casting process. Overall, test results indicate that latex additions do not impart significant improvements to the performance of centrifugally cast liners and may even be detrimental. Corrosion at steel-concrete interfaces appears to be localized and the area fraction of corroding interfaces can be greater in latex-modified concretes than in API baseline material. EPMA shows higher interfacial Cl concentration in the latex-modified concretes than in the API standard due to rapid brine transport through cracks to the steel surface.

A multimechanism constitutive model of creep has been developed which incorporates the workhardening and recovery transient creep behavior. This model has been applied to the creep of polycrystalline halite. The specific application of the model is in the calculation of the closure of underground rooms in layered salt deposits. Through the use of finite element calculations, this model, with appropriate laboratory material parameters and a Tresca flow potential, has predicted the measured closure of a number of large in situ experimental rooms.

Alkali metal heat-pipe receivers have been identified as a desirable interface to couple a Stirling-cycle engine with a parabolic dish solar concentrator. The reflux receiver provides power nearly isothermally to the engine heater heads while de-coupling the heater head design from the solar absorber surface design. The independent design of the receiver and engine heater head leads to high system efficiency. Heat pipe reflux receivers have been demonstrated at approximately 30 kW{sub t} power throughput by others. This size is suitable fm engine output powers up to 10 kW{sub e}. Several 25-kW{sub e}, Stirling-cycle engines exist, as well as designs for 75-kW{sub t} parabolic dish solar concentrators. The extension of heat pipe technology from 30 kW{sub t} to 75 kW{sub t} is not trivial. Heat pipe designs are pushed to their limits, and it is critical to understand the flux profiles expected from the dish, and the local performance of the wick structure. Sandia has developed instrumentation to monitor and control the operation of heat pipe reflux receivers to test their throughput limits, and analytical models to evaluate receiver designs. In the past 1.5 years, several heat pipe receivers have been tested on Sandia`s test bed concentrators (TBC`s) and 60-kW{sub t} solar furnace. A screen-wick heat pipe developed by Dynatherm was tested to 27.5 kW{sub t} throughput. A Cummins Power Generation (CPG)/Thermacore 30-kW{sub t} heat pipe was pushed to a throughput of 41 kW{sub t} to verify design models. A Sandia-design screen-wick and artery 75-kW{sub t} heat pipe and a CPG/Thermacore 75-kW{sub t} sintered-wick heat pipe were also limit tested on the TBC. This report reviews the design of these receivers, and compares test results with model predictions.

This paper compares the solderability performance and corrosions ion protection effectiveness of electroless tin coatings versus organic azole films after exposure to a series of humidity and thermal (lead-free solders) cycling conditions. The solderability of immersion tin is directly related to the tin oxide growth on the surface and is not affected by the formation of Sn-Cu intermetallic phases as long as the intermetallic phase is protected by a Sn layer. For a nominal tin thickness of 60{mu}inches, the typical thermal excursions associated with assembly are not sufficient to cause the intermetallic phase to consume the entire tin layer. Exposure to humidity at moderate to elevated temperatures promotes heavy tin oxide formation which leads to solderability loss. In contrast, thin azole films are more robust to humidity exposure; however upon heating in the presence of oxygen, they decompose and lead to severe solderability degradation. Evaluations of lead-free solder pastes for surface mount assembly applications indicate that immersion tin significantly improves the spreading of Sn:Ag and Sn:Bi alloys as compared to azole surface finishes.

A variety of industrial-standard and experimental concretes are being evaluated for use in brine disposal pipelines operated by the US Strategic Petroleum Reserve (SPR). This paper reports on interim performance results from on-going studies involving an American Petroleum Institute (API) standard calcium silicate-based (CS) concrete and a commercially available calcium aluminate-based (CA) concrete. Samples exposed to non-flowing SPR brine in the field were returned to the laboratory at regular intervals for analysis. Electron probe microanalysis (EPMA) determined the depth of brine penetration and the amount of concrete deterioration. Corrosion occurring at steel pipe/concrete interfaces during exposure to simulated brine has been studied on laboratory-constructed specimens using electrochemical impedance spectroscopy (EIS).

In December 1991, the Strategic Defense Initiative Organization (SDIO) decided to investigate the possibility of a US launch of a Russian Topaz II space nuclear power system. The primary mission goal would be to demonstrate and evaluate Nuclear Electric Propulsion technology to establish a capability for future civilian and military missions. A preliminary nuclear safety assessment, involving selected safety analyses, was initiated to determine whether or not a space mission could be conducted safely and within budget constraints. This paper describes the preliminary safety assessment results and the nuclear safety program now being established for the Nuclear Electric Propulsion Space Test Program (NEPSTP).

The PANDA code was used to develop an equation of state (EOS) for iron. Separate EOS tables were constructed for four solid phases and the fluid phase. The phase diagram and multiphase EOS table were then computed using the free energies. Results are in good agreement with thermophysical, static compression, phase boundary, and shock-wave measurements. Predicted pressures for the shock-induced {epsilon}-{gamma} and {gamma}-liquid transitions agree with those determined from sound speed measurements. Predicted melting temperatures fall in between two recent sets of experimental data which sharply disagree with one another.

Extensive work has been performed in the past which demonstrates that various metal alloys can be used to detect different toxic, hazardous, and flammable gases. Work has been performed using Pd, Pt, Ir, PdNi, PdAg and Pt/Pd for detecting things such as Hydrogen, Hydrazine, Hydrogen Sulfide, Deuterium, Tritium, Ethanol and Hexane. Perhaps the most familiar is the use of Pd and PdNi for the detection of Hydrogen. These devices work by examining the effect of the gases on the material properties of the metal alloys. Two of the most common material properties examined in these sensors are the resistance of thin film resistors, and the flatband or threshold voltage shifts of MOS structures fabricated with a particular alloy as the gate material. While research into these sensing techniques has shown much promise, few manufacturable, fieldable devices have resulted. These sensing techniques are prone to drift problems due to temperature variations, and typically have large sample to sample variations in performance due to process control issues. Typically, these sensors require significant external instrumentation for measurement and control, making the systems large and expensive. Sandia National Laboratories has designed, fabricated and demonstrated complete functionality of a generic microelectronic based smart sensor platform intended to effectively exploit the research mentioned above into high performance, manufacturable, fieldable devices. This smart sensor platform technology fabricates 2 {mu}m CMOS digital and analog control electronics, sensing elements, and temperature control elements on the same silicon integrated circuit. Our initial demonstration of this technology incorporates PdNi as the sensing alloy for the detection of hydrogen.

The RADionuclide Transport, Removal, And Dose (RADTRAD) code is designed for US Nuclear Regulatory Commission (USNRC) use to calculate the radiological consequences to the offsite population and to control room operators following a design-basis accident at Light Water Reactor (LWR) power plants. This code utilizes updated reactor accident source terms published in draft NUREG-1465, ``Accident Source Terms for Light-Water Nuclear Power Plants.`` The code will track the transport of radionuclides as they are released from the reactor pressure vessel, travel through the primary containment and other buildings, and are released to the environment. As the radioactive material is transported through the primary containment and other buildings, credit for several removal mechanisms may be taken including sprays, suppression pools, overlying pools, filters, and natural deposition. Simple models are available for these different removal mechanisms that use, as input, information about the conditions in the plant and predict either a removal coefficient ({lambda}) or decontamination factor. The user may elect to use these models or input a single value for a removal coefficient or decontamination factor.

A preconceptual design for an Accelerator Production of Tritium (APT) facility is currently under development by several national laboratories in conjunction with industry. The design consists of an accelerator that bombards a spallation target with high energy protons. Neutrons are produced in the spallation target and are absorbed in a blanket material to produce tritium. Two spallation targets are currently under investigation: (1) a tungsten neutron source target and (2) a lead neutron source target. In the tungsten target the neutrons are captured in helium-3, which is circulated through the system, thus producing tritium. The lead target is surrounded with a lithium-aluminum blanket and the tritium is produced in the lithium-6. The investigation of possible radiological impacts on the public is being performed as a part of the safety evaluations of the preconceptual design. These studies include the estimation of releases of radioactive materials from the two spallation targets and the possible impacts on the public.

A research and development program is being conducted by the University of Kentucky/Center for Applied Energy Research, Sandia National Laboratories, LDP Associates and CONSOL Inc. to improve current coal liquefaction technology by physical and chemical pretreatments of the coal and recycle oil. These pretreatment steps include: (1) agglomeration of the coal with ash-containing recycle oil to simultaneously reject coal ash and recycle-oil ash, (2) fluid coking of the distillation bottoms (ash-purge) stream and recycle of the coker overhead, (3) dewaxing of the distillate portion of the recycle oil, and (4) low-severity hydrotreatment of the coker overhead and dewaxed oil using hydrogen from an in-situ water-gas shift reaction. These pretreatment steps will remove the ash and unconverted coal, reducing the ash load in the system and simultaneously recovering the maximum amount of organics. Dewaxing and hydrotreatment will yield a high-quality recycle oil distillate. These pretreatment steps are being evaluated technically and economically to develop an improved conceptual liquefaction process. The baseline process to which the improved process will be compared is the Two-Stage Liquefaction Process as it was practiced at the Wilsonville, AL, USA Advanced Coal Liquefaction Test Facility.