The U.S. Department of Energy`s Office of Technology Development has been developing robotics and automation technologies for the clean-up and handling of hazardous and radioactive waste through one of its major elements, Cross Cutting and Advanced Technology development. CC&AT university research and development programs recognize the strong technology, base resident in the university community and sponsor a focused technology research and development program which stresses close interaction between the university sector and the DOE community. This report contains a compilation of research articles by each of 14 principle investigators supported by CC&AT to develop robotics and automation technologies for the clean-up and handling of hazardous and radioactive waste. This research has led to innovative solutions for waste clean-up problems, and it has moved technology out of university laboratories into functioning systems which has allowed early evaluation by site technologists.
We present a motion planner for the classical mover`s problem in three dimensions that is both resolution-complete and efficient in that it has performance commensurate with task difficulty. It is based on the SANDROS search strategy, which uses a hierarchical, multi-resolution representation of the configuration space along with a generate-and-test paradigm for solution paths. This planner can control the trade-offs between the computation resource and algorithmic completeness/solution path quality, and thus can fully utilize the available computing power. It is useful for navigation of mobile robots, submarines and spacecraft, or part motion feasibility in assembly planning.
A percolation model is developed which accounts for most known features of the process of porous glass membrane preparation by selective dissolution of multi-component glasses. The model is founded within tile framework of the classical percolation theory, wherein the components of a glass are represented by random sites on a suitable lattice. Computer simulation is used to mirror the generation of a porous structure during the dissolution process, reproducing many of the features associated with the phenomenon. Simulation results evaluate the effect of the initial composition of the glass on the kinetics of the leaching process as well as the morphology of the generated porous structure. The percolation model establishes the porous structure as a percolating cluster of unreachable constituents in the glass. The simulation algorithm incorporates removal of both, the accessible leachable components in the glass as well as the independent clusters of unreachable components not attached to the percolating cluster. The dissolution process thus becomes limited by the conventional site percolation thresholds of the unreachable components (which restricts the formation of the porous network), as well as the leachable components (which restricts the accessibility of the solvating medium into the glass). The simulation results delineate the range of compositional variations for successful porous glass preparation and predict the variation of porosity, surface area, dissolution rates and effluent composition with initial composition and time. Results compared well with experimental studies and improved upon similar models attempted in die past.
Emissive flat panel display systems operating in full color demand higher performance at low voltages (ca. 501000 V) from cathodoluminescent (CL) phosphors than cathode ray tubes require. Hydrothermal synthesis has been suggested as a route to phosphors with improved efficiencies, lower voltage thresholds, and increased saturation power. This hypothesis was tested in europium-doped yttrium orthovanadate (YVO{sub 4}:Eu), an efficient, red emitting CL phosphor. The CL efficiency of YVO{sub 4}:Eu crystallized from aqueous solution at 200{degrees}C is relatively low until it is annealed. The distribution of particle sizes in the low-temperature phosphor is similar to that in material made via a solid-state route, but crystallites remain much smaller (ca. 400 {Angstrom}) until they are annealed. These observations, along with the anomalously strong dependence of CL intensity on europium concentration, support a model in which efficiency principally depends on crystallite size. CL efficiency of both solid state and hydrothermal YVO{sub 4}:Eu increases with voltage at constant power. Surface-bound electrons are likely the dominant influence on efficiency at voltages near threshold. Saturation power is independent of synthetic route. It is apparent that the CL properties of hydrothermally synthesized YVO{sub 4}:Eu are essentially the same as those of YVO{sub 4}:Eu produced via conventional, high-temperature routes.
To address the need for a fast path planner, we present a learning algorithm that improves path planning by using past experience to enhance future performance. The algorithm relies on an existing path planner to provide solutions difficult tasks. From these solutions, an evolving sparse work of useful robot configurations is learned to support faster planning. More generally, the algorithm provides a framework in which a slow but effective planner may be improved both cost-wise and capability-wise by a faster but less effective planner coupled with experience. We analyze algorithm by formalizing the concept of improvability and deriving conditions under which a planner can be improved within the framework. The analysis is based on two stochastic models, one pessimistic (on task complexity), the other randomized (on experience utility). Using these models, we derive quantitative bounds to predict the learning behavior. We use these estimation tools to characterize the situations in which the algorithm is useful and to provide bounds on the training time. In particular, we show how to predict the maximum achievable speedup. Additionally, our analysis techniques are elementary and should be useful for studying other types of probabilistic learning as well.
The contact between an obsidian flow and a steep-walled tuff canyon was examined as an analogue for a high-level waste repository. The analogue site is located in the Valles Caldera in New Mexico, where a massive obsidian flow filled a paleocanyon in the Battleship Rock Tuff. The obsidian flow provided a heat source, analogous to waste panels or an igneous intrusion in a repository, and caused evaporation and migration of water. The tuff and obsidian samples were analyzed for major and trace elements and mineralogy by INAA, XRF, x-ray diffraction, and scanning electron microscopy and electron microprobe. Samples were also analyzed for D/H and {sup 39}Ar/{sup 40}Ar isotopic composition. Overall, the effects of the heating event seem to have been slight and limited to the tuff nearest the contact. There is some evidence of devitrification and migration of volatiles in the tuff within 10 m of the contact, but variations in major and trace element chemistry are small and difficult to distinguish from the natural (pre-heating) variability of the rocks.
The sorption of Cs and Cd on model soil minerals was examined by complementary analytical and experimental procedures. X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) spectroscopy were used to characterize the chemical and physical nature of Cs-reacted soil minerals. Cd and Cs adsorption isotherms for kaolinite were also measured at variable pH and temperature to establish likely reaction stoichiometries, while atomic force microscopy (AFM) was used to characterize the microtopography of the clay surface. XPS analyses of Cs-exchanged samples show that Cs is sorbed at mineral surfaces and at the interlayer site of smectite clays, although the spectral resolution of XPS analyses is insufficient to differentiate between basal, edge or interlayer sites. {sup 133}Cs MAS-NMR results also show that Cs is adsorbed primarily in an interlayer site of montmorillonite and on edge and basal sites for kaolinite. Cd adsorption isotherms on kaolinite were found to be additive using Al{sub 2}0{sub 3} + Si0{sub 2} Cd binding constants. AFM quantification of kaolinite crystallites suggest that edges comprise up to 50% of the BET surface area, and are consistent with NMR and surface charge results that Cs an Cd adsorption occur primarily at edge sites.
Sandia National Laboratories has worked with Synthetica Technologies and Manufacturing and Technology Conversion International (MTCl) to demonstrate the applicability of their commercial steam reforming technologies for treating DOE low-level mixed wastes. Previously, Synthetica successfully demonstrated destruction of a Sandia formulated lab trash simulant. During November 1994 Synthetica did not adequately process the aqueous halogenated organic liquid mixed waste simulant (MWTP-2110) formulated by the DOE Mixed Waste Integrated Program (MWIP). Testing at MTCl is ongoing and initial results appear to be favorable. Approximately 200 lbs each of the MWIP aqueous halogenated organic liquids (MWTP-2110), and absorbed aqueous and organic liquids (MWTP-3113/3114) simulants have been processed. At 1650{degree}F, destruction efficiencies of greater than 99% were obtained for tetrachloroethylene, toluene, and 1,2 dichlorobenzene. Product cases consisted primarily of H{sub 2}, C0{sub 2}, CO, and CH{sub 4} and had higher heating values of up to 355 BTU/SCF. Conclusions concerning the suitability of the MTCI process for treating DOE mixed wastes will be drawn upon the completion of testing.
Public concerns about surface water quality and its impact on health issues have put a premium on the ability to predict surface and groundwater quality in urban areas. The movement of toxins and nutrients in urban areas is largely controlled by interactions with soil and aquifer minerals along hydrologic pathways. Despite progress in theoretical modeling of the effects of these interactions on water chemistry, it is presently impossible to predict overall trends in urban water quality. Determining the controls on stream water chemistry is problematic due to the interplay between different hydrologic reservoirs which cannot be easily observed or measured. Natural tracers, such as dissolved ions and isotopes, provide an indirect method for observing subsurface interactions and are useful for time series analysis of stream water composition. Ionic species are generally nonconservative components because of chemical reactions and are thus useful for discerning the overall discharge chemistry affected by the relationship.
The primary purpose of this paper is to provide a careful evaluation of the diffusion velocity concept with regard to its ability to predict the diffusion of vorticity near a moving wall. A computer code BDIF has been written which simulates the evolution of the vorticity field near a wall of infinite length which is moving in an arbitrary fashion. The simulations generated by this code are found to give excellent results when compared to several exact solutions. We also outline a two-dimensional unsteady viscous boundary layer model which utilizes the diffusion velocity concept and is compatible with vortex methods. A primary goal of this boundary layer model is to minimize the number of vortices generated on the surface at each time step while achieving good resolution of the vorticity field near the wall. Preliminary results have been obtained for simulating a simple two-dimensional laminar boundary layer.
Sol-gel processing has been widely used in the preparation of lead zirconate titanate (PZT) thin films. The authors have applied this methodology to the formation of lead magnesium niobate (PMN) spin-cast deposited thin films. Since there is a limited number of soluble, commercially available compounds, the authors have recently synthesized a series of novel metal alkoxides for use as precursors for generation of PMN thin films and powders. The process for generation of the perovskite phase of these PMN powders and films are reported.
The numerical code TOUGH2 was used to assess alternative conceptual models of fracture flow. The models that were considered included the equivalent continuum model (ECM) and the dual permeability (DK) model. A one-dimensional, layered, unsaturated domain was studied with a saturated bottom boundary and a constant infiltration at the top boundary. Two different infiltration rates were used in the studies. In addition, the connection areas between the fracture and matrix elements in the dual permeability model were varied. Results showed that the two conceptual models of fracture flow produced different saturation and velocity profiles-even under steady-state conditions. The magnitudes of the discrepancies were sensitive to two parameters that affected the flux between the fractures and matrix in the dual permeability model: (1) the fracture-matrix connection areas and (2) the capillary pressure gradients between the fracture and matrix elements.
This paper discusses, in a general way, the influence of technology on the economy. The target audience is engineers who are involved in technology development but who are not especially familiar with economics. The measure used for describing the health of an economy is productivity. The impact of technological developments on productivity is discussed.
Hazardous materials management includes interactions among materials, personnel, facilities, hazards, and processes of various groups within a DOE site`s environmental, safety & health (ES&H) and line organizations. Although each group is charged with addressing a particular aspect of these properties and interactions, the information it requires must be gathered into a coherent set of common data for accurate and consistent hazardous material management and regulatory reporting. It is these common data requirements which the Cradle-to-Grave Tracking and Information System (CGTIS) is designed to satisfy. CGTIS collects information at the point at which a process begins or a material enters a facility, and maintains that information, for hazards management and regulatory reporting, throughout the entire life-cycle by providing direct on-line links to a site`s multitude of data bases to bring information together into one common data model.
The RADTRAN computer code for transportation risk analysis, which has been under continuous development at Sandia National Laboratories since 1977, has evolved from a purely research tool into a publicly available with a variety of applications. This expansion of the user community has substantially increased the need to make the system easier to use without decreasing its capabilities or the quality of output. A large set of modifiable RADTRAN input files has been available via TRANSNET for several years. One approach to assisting the user involves adding annotations/information to each of these files. A second approach is providing additional help in building new/modifying old input files. Keeping the proposed information/annotation files separate from but closely coupled to the modifiable input files within the TRANSNET shell system allows the modifiable input files to remain as regular input files while providing rapid, automatic access to, useful information about the analysis. In this way, the sample input files remain intact as regular RADTRAN input files and any files generated using associated on-line menus or editors may be readily converted into new input files. A single sample file is selected and used as an example to illustrate the prototype help features.
Scenario development for the system performance assessment of the Yucca Mountain Site Characterization Project defines a scenario as a well-posed problem connecting an initiating event with radionuclide release to the accessible environment by a logical and physically possible combination or sequence of features, events, and processes. Drawing on the advice and assistance of the Project`s principal investigators (PIs), a collection of release scenarios initiated by the nominal ground-water flow occurring in the vicinity of the potential Yucca Mountain high-level-waste repository is developed and described in pictorial form. This collection of scenarios is intended to provide a framework to assist PIs in recognizing essential field and calculational analyses, to assist performance assessment in providing guidance to site characterization, and to continue the effort to exhaustively identify all features, events, and processes important to releases. It represents a step in the iterative process of identifying what details of the potential site are important for safe disposal. 67 refs.
Correct operation of an information system requires a balance of ``surety`` domains -- access control (confidentiality), integrity, utility, availability, and safety. However, traditional approaches provide little help on how to systematically analyze and balance the combined impact of surety requirements on a system. The key to achieving information system surety is identifying, prioritizing, and mitigating the sources of risk that may lead to system failure. Consequently, the authors propose a risk assessment methodology that provides a framework to guide the analyst in identifying and prioritizing sources of risk and selecting mitigation techniques. The framework leads the analyst to develop a risk-based system model for balancing the surety requirements and quantifying the effectiveness and combined impact of the mitigation techniques. Such a model allows the information system designer to make informed trade-offs based on the most effective risk-reduction measures.
The agile manufacturing paradigm engenders many new concepts and work approaches for manufacturing operations. A technology often invoked in the concept of agility is modeling and simulation. Few would disagree that modeling and simulation holds the potential to substantially reduce the product development cycle and lead to improve product reliability and performance. Advanced engineering simulation can impact manufacturing in three areas: process design, product design, and process control. However, despite that promise, the routine utilization of modeling and simulation by industry within the design process is very limited. Advanced simulation is still used primarily in a troubleshooting mode examining design or process problems after the fact. Sandia National Laboratories has been engaged in the development of advanced engineering simulation tools for many years and more recently has begun to focus on the application of such models to manufacturing processes important for the defense industry. These efforts involve considerable interaction and cooperative research with US industry. Based upon this experience, this presentation examines the elements that are necessary for advanced engineering simulation to become an integral part of the design process.
This paper presents experimental data and computational modeling for a well-defined glass material. The experimental data cover a wide range of strains, strain rates, and pressures that are obtained from quasi-static compression and tension tests, split Hopkinson pressure bar compression tests, explosively driven flyer plate impact tests, and depth of penetration ballistic tests. The test data are used to obtain constitutive model constants for the improved Johnson-Holmquist (JH-2) brittle material model. The model and constants are then used to perform computations of the various tests.
At Sandia National Laboratories in Albuquerque, the author designed and fabricated a precision wire feeder to be used with high energy density (electron beam and laser beam) welding for weld joints where filler wire might be needed to fill a gap or to adjust the chemical composition so that a crack-free weld could be made. The wire feeder incorporates a 25,000 step-per-revolution motor to power a urethane-coated drive roll. A microprocessor-based controller provides precise control of the motor and allows both continuous and pulsed feeding of the wire. A unidirectional 0.75-in.-dia ball bearing is used to press the wire against the drive roll. A slight constant backward tension is maintained on the wire spool by a Bodine torque motor. A Teflon tube is used to guide the wire from the drive roll to the vicinity of the weld, where a hypodermic needle is used to aim the wire into the weld pool. The operation of the wire feeder was demonstrated by feeding a 10-mil-dia, Type 304 stainless steel wire into a variety of CO{sub 2} laser beam welds. The resulting welds are smooth and continuous, and the welds are considered to be completely satisfactory for a variety of applications.
Several government agencies and industrial sectors have recognized the need for, and payoff of, investing in the methodologies and associated technologies for improving the product realization process. Within the defense community as well as commercial industry, there are three major needs. First, they must reduce the cost of military products, of related manufacturing processes, and of the enterprises that have to be maintained. Second, they must reduce the time required to realize products while still applying the latest technologies. Finally, they must improve the predictability of process attributes, product performance, cost, schedule and quality. They must continue to advance technology, quickly incorporate their innovations in new products and in processes to produce them, and they need to capitalize on the raw computational power and communications bandwidth that continues to become available at decreasing cost. Sandia National Laboratories initiative is pursuing several interrelated, key concepts and technologies in order to enable such product realization process improvements: model-based design; intelligent manufacturing processes; rapid virtual and physical prototyping; and agile people/enterprises. While progress in each of these areas is necessary, this paper only addresses a portion of the overall initiative. First a vision of a desired future capability in model-based design and virtual prototyping is presented. This is followed by a discussion of two specific activities parametric design analysis of Synthetic Aperture Radars (SARs) and virtual prototyping of miniaturized high-density electronics -- that exemplify the vision as well as provide a status report on relevant work in progress.
One of the tasks of the Lethality Group within US Army Space and Strategic Defense Command (USASSDC) is the development of a capability to simulate various missile intercept scenarios using computer codes. Currently under development within USASSDC and its various contractor organizations is a group of codes collected under a master code called PEGEM for Post Event Ground Effects Model. Among the various components of the code are modules which are used to predict atmospheric dispersion and transport of particles or droplets following release at the altitude specified in the missile intercept scenario. The atmospheric transport code takes into account various source term data from the intercept such as: initial cloud size; droplet or particle size distribution; and, total mass of agent released. An ongoing USASSDC experimental program termed Crystal Mist involved release of precision glass beads under various altitude and meteorological conditions to assist in validation and refinement of various codes that are components of PEGEM used to predict particle atmospheric transport and diffusion following a missile intercept. Here, soda-lime glass beads used in the Crystal Mist series of atmospheric transport and diffusion tests were characterized by scanning electron microscopy and automated image processing routines in order to fully define their size distributions and morphology. Four bead size classifications ranging from a median count diameter of 45 to 200 micrometers were found to be approximately spherical and to fall within the supplier`s sizing specifications. Log-normal functions fit to the measured size distributions resulted in geometric standard deviations ranging from 1.08 to 1.12, thereby fulfilling the field trial requirements for a relatively narrow bead size distribution.
A novel, folded compact range configuration has been developed at the Sandia National Laboratories compact range antenna and radar cross section measurement facility, operated by the Radar/Antenna Department 2343, as a means of performing indoor, environmentally-controlled, far-field simulations of synthetic aperture radar (SAR) coherent change detection (CCD) measurements. This report describes the development of the folded compact range configuration, as well as the initial set of coherent change detection measurements made with the system. These measurements have been highly successful, and have demonstrated the viability of the folded compact range concept in simulating SAR CCD measurements. It is felt that follow-on measurements have the potential of contributing significantly to the body of knowledge available to the scientific community involved in CCD image generation and processing, and that this tool will be a significant aid in the research and development of change detection methodologies.
This report summarizes a number of research efforts completed over the past 20 years in the El Paso del Norte region to characterize pollution sources and air quality trends. The El Paso del Norte region encompasses the cities of El Paso, Texas and Ciudad Juarez, Chihuahua and is representative of many US-Mexico border communities that are facing important air quality issues as population growth and industrialization of Mexican border communities continue. Special attention is given to a group of studies carried out under special US Congressional funding and administered by the US Environmental Protection Agency. Many of these studies were fielded within the last several years to develop a better understanding of air pollution sources and trends in this typical border community. Summary findings from a wide range of studies dealing with such issues as the temporal and spatial distribution of pollutants and pollution potential from both stationary and mobile sources in both cities are presented. Particular emphasis is given to a recent study in El Paso-Ciudad Juarez that focussed on winter season PM{sub 10} pollution in El Paso-Ciudad Juarez. Preliminary estimates from this short-term study reveal that biomass combustion products and crustal material are significant components of winter season PM{sub 10} in this international border community.
This report summarizes the activities of a Lab Directed Research and Development (LDRD) Project to investigate the viability of asynchronous transfer mode (ATM) switching technology in the local area network (LAN) environment. A number of ATM based LANs were constructed and their performance capabilities were measured. The summary report notes the measurements and lessons learned from the two-year effort.
In today`s world, accurate finite-element simulations of large nonlinear systems may require meshes composed of hundreds of thousands of degrees of freedom. Even with today`s fast computers and the promise of ever-faster ones in the future, central processing unit (CPU) expenditures for such problems could be measured in days. Many contemporary engineering problems, such as those found in risk assessment, probabilistic structural analysis, and structural design optimization, cannot tolerate the cost or turnaround time for such CPU-intensive analyses, because these applications require a large number of cases to be run with different inputs. For many risk assessment applications, analysts would prefer running times to be measurable in minutes. There is therefore a need for approximation methods which can solve such problems far more efficiently than the very detailed methods and yet maintain an acceptable degree of accuracy. For this purpose, we have been working on two methods of approximation: neural networks and spring-mass models. This paper presents our work and results to date for spring-mass modeling and analysis, since we are further along in this area than in the neural network formulation. It describes the physical and numerical models contained in a code we developed called STRESS, which stands for ``Spring-mass Transient Response Evaluation for structural Systems``. The paper also presents results for a demonstration problem, and compares these with results obtained for the same problem using PRONTO3D, a state-of-the-art finite element code which was also developed at Sandia.
Traditional approaches to the assessment of information systems have treated system security, system reliability, data integrity, and application functionality as separate disciplines. However, each areas requirements and solutions have a profound impact on the successful implementation of the other areas. A better approach is to assess the ``surety`` of an information system, which is defined as ensuring the ``correct`` operation of an information system by incorporating appropriate levels of safety, functionality, confidentiality, availability, and integrity. Information surety examines the combined impact of design alternatives on all of these areas. We propose a modelling approach that combines aspects of fault trees and influence diagrams for assessing information surety requirements under a risk assessment framework. This approach allows tradeoffs to be based on quantitative importance measures such as risk reduction while maintaining the modelling flexibility of the influence diagram paradigm. This paper presents an overview of the modelling method and a sample application problem.
A thermomechanical analysis of a continuous fiber metal matrix composite (MMC) subjected to cyclic loading is performed herein. The analysis includes the effects of processing induced residual thermal stresses, matrix inelasticity, and interface cracking. Due to these complexities, the analysis is performed computationally using the finite element method. Matrix inelasticity is modelled with a rate dependent viscoplasticity model. Interface fracture is modelled by the use of a nonlinear interface constitutive model. The problem formulation is summarized, and results are given for a four-ply unidirectional SCS-6/{beta}21S titanium composite under high temperature isothermal mechanical fatigue. Results indicate rate dependent viscoplasticity can be a significant mechanism for dissipating the energy available for damage propagation, thus contributing to improved ductility of the composite. Results also indicate that the model may be useful for inclusion in life prediction methodologies for MMC`s.
In this paper a brief description of dynamic techniques commonly available for determining material property studies is presented. For many impact applications, the material generally experiences a complex loading path. In most cases, the initial loading conditions can be represented by the shock commonly referred to as the Hugoniot state. Subsequent loading or release structure, i.e., off-Hugoniot states would however be dependent on the physical processes dominating the material behavior. The credibility of the material model is tested by the accuracy of predictions of off-Hugoniot states. Experimental techniques commonly used to determine off-Hugoniot states are discussed in this survey.
There has been some concern that, as nuclear power plants age, protective measures taken to control and minimize the impact of fire may become ineffective, or significantly less effective, and hence result in an increased fire risk. One objective of the Fire Vulnerability of Aged Electrical Components Program is to assess the effects of aging and service wear on the fire vulnerability of electrical equipment. An increased fire vulnerability of components may lead to an overall increase in fire risk to the plant. Because of their widespread use in various electrical safety systems, electromechanical relays were chosen to be the initial components for evaluation. This test program assessed the impact of operational and thermal aging on the vulnerability of these relays to fire-induced damage. Only thermal effects of a fire were examined in this test program. The impact of smoke, corrosive materials, or fire suppression effects on relay performance were not addressed in this test program. The purpose of this test program was to assess whether the fire vulnerability of electrical relays increased with aging. The sequence followed for the test program was to: identify specific relay types, develop three fire scenarios, artificially age several relays, test the unaged and aged relays in the fire exposure scenarios, and compare the results. The relays tested were Agastat GPI, General Electric (GE) HMA, HGA, and HFA. At least two relays of each type were artificially aged and at least two relays of each type were new. Relays were operationally aged by cycling the relay under rated load for 2,000 operations. These relays were then thermally aged for 60 days with their coil energized.
An approach is described for performing scoping calculations of radionuclide release fractions from target materials being considered for use in the Accelerator Production of Tritium (APT) project, and some illustrative results are presented. The releases are evaluated for postulated accident scenarios involving severe overheating of either of two neutron source target materials, tungsten and lead. The potential for vaporization of radionuclides produced by spallation and neutron capture reactions is evaluated using a model that includes production of volatile species by reaction with steam, hydrogen, and/or oxygen. Emphasis is on release from the neutron source materials themselves, with a more limited treatment being given for radionuclides produced in other parts of the target/blanket assemblies. In the tungsten neutron source target, the low rate of diffusion within the tungsten is shown to limit releases of even volatile species to small values in a chemically inert or reducing environment. However, oxidative ablation of tungsten could permit considerably larger releases of volatile species in steam-rich or oxygen-rich environments. Tungsten radionuclides would dominate the source term for accident conditions considered the most plausible. For the lead neutron source target, the releases are predicted to be dominated by mercury radionuclides. Quantitative source term evaluation for this target is complicated because, in any accident sufficiently severe to be of much concern, lead melting will likely result in loss of target geometry. Hence, results presented for release from the lead must be carefully qualified. Extensive parametric results are presented for release from both neutron source materials. These results may be used to perform scoping estimates of radionuclide releases for additional APT accident scenarios as the controlling parameters for these scenarios become better defined.
The majority of all oil well footage drilled is in shales and other clay-bearing rocks. The mechanical strength of these formations usually is not an issue as regards their fast penetration by the drill bit. The difficulties associated with these formations arise due to the chemically reactive nature of such formations, causing the cuttings to stick to the bit. This causes a decrease in the rate of penetration of the drill bit and also has a detrimental effect on the state of the wellbore. This report presents a radical approach to preventing the adherence of shale cuttings to the bit. It consists of applying a direct electrical potential between the rock and the bit while drilling, while making the latter the cathode. Due to the process of electro-osmosis that occurs in shales, this results in the migration of a thin layer of water to the interface between the metal body (cathode) and the rock (anode). It has been demonstrated that this layer of water at the interface aids in the penetration of single-point indenters and also facilitates their withdrawal. Interfacial friction between a shale and a metal body was reduced, as was the tendency of shale cuttings to adhere to the metal surface. All of these combined to cause significant increases in the rate of penetration of a cathodic bit, as compared to the case when no potential was applied. It has been shown that when the bit was made the cathode, the maximum advantage was obtained when drilling conditions got worse, making it ideally suited for field applications. It was also shown that in the time intervals relevant to drilling operations, an amount of water sufficient to provide a coating on the bit was migrated out of a shale. It is believed that since the contact between the metal and the shale completes the electrical circuit to produce the driving force, this technique should work under most operating conditions. 63 refs.
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. The goal of this program is to assist industry in developing cost-effective battery systems as a utility resource option by 2000. Sandia is responsible for the engineering analyses, contracted development, and testing of rechargeable batteries and systems for utility energy storage applications. This report details the technical achievements realized during fiscal year 1994.
The purpose of this document is to describe a qualitative risk assessment process that supplements the requirements of DOE/AL 5481.1B. Although facility managers have a choice of assessing risk either quantitatively or qualitatively, trade offs are involved in making the most appropriate choice for a given application. The results that can be obtained from a quantitative risk assessment are significantly more robust than those results derived from a qualitative approach. However, the advantages derived from quantitative risk assessment are achieved at a greater expenditure of money, time and convenience. This document provides the elements of a framework for performing a much less costly qualitative risk assessment, while retaining the best attributes of quantitative methods. The approach discussed herein will; (1) provide facility managers with the tools to prepare consistent, site wide assessments, and (2) aid the reviewers who may be tasked to evaluate the assessments. Added cost/benefit measures of the qualitative methodology include the identification of mechanisms for optimally allocating resources for minimizing risk in an expeditious, and fiscally responsible manner.
The Plasma Technology Directory has two main goals: (1) promote, coordinate, and share plasma technology experience and equipment within the Department of Energy; and (2) facilitate technology transfer to the commercial sector where appropriate. Personnel are averaged first by Laboratory and next by technology area. The technology areas are accelerators, cleaning and etching deposition, diagnostics, and modeling.
This paper presents a concept for fusing 3-dimensional image reconnaissance data with LADAR imagery for aim point refinement. The approach is applicable to fixed or quasi-fixed targets. Quasi-fixed targets are targets that are not expected to be moved between the time of reconnaissance and the time of target engagement. The 3-dimensional image data is presumed to come from standoff reconnaissance assets tens to hundreds of kilometers from the target area or acquisitions prior to hostilities. Examples are synthetic aperture radar (SAR) or stereoprocessed satellite imagery. SAR can be used to generate a 3-dimensional map of the surface through processing of data acquired with conventional SAR acquired using two closely spaced, parallel reconnaissance paths, either airborne or satellite based. Alternatively, a specialized airborne SAR having two receiving antennas may be used for data acquisition. The data sets used in this analysis are: (1) LADAR data acquired using a Hughes-Danbury system flown over a portion of Kirtland AFB during the period September 15--16, 1993; (2) two pass interferometric SAR data flown over a terrain-dominated area of Kirtland AFB; (3) 3-dimensional mapping of an urban-dominated area of the Sandia National Laboratories and adjacent cultural area extracted from aerial photography by Vexcel Corporation; (4) LADAR data acquired at Eglin AFB under Wright Laboratory`s Advanced Technology Ladar System (ATLAS) program using a 60 {mu}J, 75 KHz Co{sub 2} laser; and (5) two pass interferometric SAR data generated by Sandia`s STRIP DCS (Data Collection System) radar corresponding to the ATLAS LADAR data. The cultural data set was used in the urban area rather than SAR because high quality interferometric SAR data were not available for the urban-type area.
Finite Element Analysis capability for application to welding has been developed and enhanced during a two year Cooperative Research and Development Agreement(CRADA) between Pratt & Whitney, United Technologies Research Center, and Sandia National Laboratories. Because of the nature of electron beam welding at Pratt & Whitney -- set-up is time consuming, the parts to be welded are complicated, and experimentation is costly -- finite element analysis has found many potential applications. The results of most interest in these analyses are the residual stress and final distortion of the component. The work has made use of the Sandia finite element codes JACQ3D, for thermal analysis, and JAS3D, for mechanical analysis. Both codes use an efficient, non-linear conjugate gradient solution technique, which enables large problems to be solved on engineering workstations. This presentation describes several technical challenges that were overcome in the application of the Sandia codes to this class of problems. Stress and distortion results predicted for an electron beam weld of a PW4000 gas turbine engine drum rotor will also be discussed.
Selecting a risk-based tool to aid in decision making is as much of a challenge as properly using the tool once it has been selected. Failure to consider customer and stakeholder requirements and the technical bases and differences in risk-based decision making tools will produce confounding and/or politically unacceptable results when the tool is used. Selecting a risk-based decisionmaking tool must therefore be undertaken with the same, if not greater, rigor than the use of the tool once it is selected. This paper presents a process for selecting a risk-based tool appropriate to a set of prioritization or resource allocation tasks, discusses the results of applying the process to four risk-based decision-making tools, and identifies the ``musts`` for successful selection and implementation of a risk-based tool to aid in decision making.
Safety is of paramount concern in todays high technology environment. Because of technological advances, there are numerous situations (high consequence operations) for which the implications of a safety failure are so severe that extreme attention to safety systems is essential. Some of those situations are: nuclear weapon detonation safety, nuclear reactor safety, dam safety, mass transit transportation safety, and hazardous materials transportation and handling safety. In each case, specific safety systems, human control, and administrative procedures have been designed to give a high level of assurance against disasters. In an overview sense, safety concepts can be divided into two broad approaches: active safety and passive safety. Active safety systems, in general, are based on the need for ``functioning`` elements (operating motors, operator action, etc.) and safety may be based in a large measure on ``reliability`` data (historical records of the operability success of components). Passive safety basically depends on non-functionality.
With the infusion of information technologies into product development and production processes, effective management of product data is becoming essential to modern production enterprises. When an enterprise-wide Product Data Manager (PDM) is implemented, PDM designers must satisfy the requirements of individual users with different job functions and requirements, as well as the requirements of the enterprise as a whole. Concern must also be shown for the interrelationships between information, methods for retrieving archival information and integration of the PDM into the product development process. This paper describes a user-driven approach applied to PDM design for an agile manufacturing pilot project at Sandia National Laboratories that has been successful in achieving a much faster design-to-production process for a precision electro mechanical surety device.
As industries position themselves for the competitive markets of today, and the increasingly competitive global markets of the 21st century, agility, or the ability to rapidly develop and produce new products, represents a common trend. Agility manifests itself in many different forms, with the agile manufacturing paradigm proposed by the Iacocca Institute offering a generally accepted, long-term vision. In its many forms, common elements of agility or agile manufacturing include: changes in business, engineering and production practices, seamless information flow from design through production, integration of computer and information technologies into all facets of the product development and production process, application of communications technologies to enable collaborative work between geographically dispersed product development team members and introduction of flexible automation of production processes. Industry has rarely experienced as dramatic an infusion of new technologies or as extensive a change in culture and work practices. Human factors will not only play a vital role in accomplishing the technical and social objectives of agile manufacturing. but has an opportunity to participate in shaping the evolution of industry paradigms for the 21st century.
The purpose of an intelligent alarm analysis system is to provide complete and manageable information to a central alarm station operator by applying alarm processing and fusion techniques to sensor information. This paper discusses the sensor fusion approach taken to perform intelligent alarm analysis for the Advanced Exterior Sensor (AES). The AES is an intrusion detection and assessment system designed for wide-area coverage, quick deployment, low false/nuisance alarm operation, and immediate visual assessment. It combines three sensor technologies (visible, infrared, and millimeter wave radar) collocated on a compact and portable remote sensor module. The remote sensor module rotates at a rate of 1 revolution per second to detect and track motion and provide assessment in a continuous 360` field-of-regard. Sensor fusion techniques are used to correlate and integrate the track data from these three sensors into a single track for operator observation. Additional inputs to the fusion process include environmental data, knowledge of sensor performance under certain weather conditions, sensor priority, and recent operator feedback. A confidence value is assigned to the track as a result of the fusion process. This helps to reduce nuisance alarms and to increase operator confidence in the system while reducing the workload of the operator.
Sandia National Laboratories faces institutional challenges that are unique in its history. Never before have the national laboratories been viewed so critically, and never before has their role been the subject of such study and debate. At the same time, the opporunities to render `exceptional service in the national interest` have never been greater. The business of Sandia today and into the foreseeable future will rely on a strong, integrated technical foundation, represented most fundamentally by its core competencies. While is is impossible to foresee precisely what missions Sandia will pursue many years from now, one thing is clear: Central to its service to the nation will be the application of science-based engineering skills to the stewardship of the nuclear weapons stockpile. Whether on not the nation ever builds a new nuclear weapon, those that remain in stockpile will require continuous stewardship based on the integration of scientific understanding with experienced systems engineering. Sandia`s steadfast commitment to DOE`s stockpile stewardship mission will also be evident in the production of limited numbers of certain vital weapon components as the weapons production complex is realigned. Complementing this enduring responsibility will be expanded missions in energy, environment, and economic competitiveness. The work for other federal agencies will be jointly sponsored under high-level agreements with DOE. Multi-institutional teams will become a common way of doing business. The multiprogram laboratory model will evolve toward a new model of multi-laboratory programs addressing major national needs. Sandia will be a distinct and important component of an integrated system of national laboratories.
Extreme UltraViolet Lithography (EUVL) seeks to apply radiation in a wavelength region centered near 13 nm to produce microcircuits having features sizes 0.1 micron or less. A critical requirement for the commercial application of this technology is the development of an economical, compact source of this radiation which is suitable for lithographic applications. A good candidate is a laser-plasma source, which is generated by the interaction of an intermediate intensity laser pulse (up to 10{sup 12} W/cm{sup 2}) with a metallic target. While such a source has radiative characteristics which satisfy the needs of an EUVL source, the debris generated during the laser-target interaction strikes at the economy of the source. Here, the authors review the use of concepts and computer modeling, originally developed for hypervelocity impact analysis, to study this problem.
Anderson, D.J.; Cranwell, R.M.; Iman, R.; Van Buren, P.D.
Environmental regulations are encouraging the development of new environmentally conscious manufacturing (ECNP processes. However, the quality and reliability of these processes and hardware produced must be understood prior to implementing these new technologies in factories. Furthermore, military hardware fabrication is governed by standards and specifications that frequently mandate the use of older, less environmentally friendly processes or materials, or prohibit the use of new ECM processes without advance military approvaL Sandia National Laboratories, with industrial and military partners, have developed methodologies for evaluating and qualifying new ECM processes for military and commercial applications, and have piloted these methodologies in qualifying new, low-residue soldering technologies and materials.
The characteristics of a piezoresistive accelerometer in shock environments are being studied at Sandia National Laboratories in the Mechanical Shock Testing Laboratory. A Hopkinson bar capability has been developed to extend our undemanding of the piezoresistive accelerometer, in two mechanical configurations, in the high frequency, high shock environments where measurements are being made. Two different Hopkinson bar materials are being used: Titanium and beryllium The in-axis performance of the piezoresistive accelerometer for frequencies of dc-10 kHz and shock magnitudes of up to 150,000 g as determined from measurements with a titanium Hopkinson bar are presented. The beryllium Hopkinson bar configuration is described. Preliminary in-axis characteristics of the piezoresistive accelerometer at a nominal shock level of 50,000 g for a frequency range of DC-30 kHz determined from the beryllium bar are presented.
The goal of assembly sequencing is to plan a feasible series of operations to construct a product from its individual parts. Previous research has thoroughly investigated assembly sequencing under the assumption that parts have nominal geometry. This paper considers the case where parts have toleranced geometry. Its main contribution is an efficient procedure that decides if a product admits an assembly sequence with infinite translations that is feasible for all possible instances of the components within the specified tolerances. If the product admits one such sequence, the procedure can also generate it. For the cases where there exists no such assembly sequence, another procedure is proposed which generates assembly sequences that are feasible only for some values of the toleranced dimensions. If this procedure produces no such sequence, then no instance of the product is assemblable. Finally, this paper analyzes the relation between assembly and disassembly sequences in the presence of toleranced parts. This work assumes a simple, but non-trivial tolerance language that falls short of capturing all imperfections of a manufacturing process. Hence, it is only one step toward assembly sequencing with toleranced parts.
There has been some interest lately in the need for ``authenticated signalling``, and the development of signalling specifications by the ATM Forum that support this need. The purpose of this contribution is to show that if authenticated signalling is required, then supporting signalling facilities for directory services (i.e. key management) are also required. Furthermore, this contribution identifies other security related mechanisms that may also benefit from ATM-level signalling accommodations. For each of these mechanisms outlined here, an overview of the signalling issues and a rough cut at the required fields for supporting Information Elements are provided. Finally, since each of these security mechanisms are specified by a number of different standards, issues pertaining to the selection of a particular security mechanism at connection setup time (i.e. specification of a required ``Security Quality of Service``) are also discussed.
A feasibility test on remote monitoring of unattended sensors was conducted by Sandia National Laboratories (SNL) and the Japan Atomic Energy Research Institute (JAERI) under a bilateral agreement between the U.S. Arms Control and Disarmament Agency (ACDA) and JAERI. The Containment and Surveillance Data Authenticated Communication (CASDAC) system developed by JAERI for nuclear safeguards and physical protection is a prototype system for remote monitoring of sensor status through the international telephone network. Sensor inputs to the CASDAC system are provided by prototype tamper-protected sensor enclosures developed by SNL on behalf of ACDA. The CASDAC system normally operates on a polling basis from the central control console at JAERI, but data transmission may also be initiated from the remote read unit at SNL when a sensor activation is detected. All transmission data are encrypted. Statistics concerning reliability, time delay for anomaly detection, and records of all sensor activations were accumulated since May 1992. This paper describes the objectives and preliminary evaluation of the accumulated data. The U.S. Defense Nuclear Agency (DNA) funded the experiment at SNL to obtain information about the potential of CASDAC for use in Chemical Weapons Convention (CWC) applications.