The US Department of Energy`s Office of Technology Development (OTD) has sponsored the development of the Generic Intelligent System Controller (GISC) for application to remote system control. Of primary interest to the OTD is the development of technologies which result in faster, safer, and cheaper cleanup of hazardous waste sites than possible using conventional approaches. The objective of the GISC development project is to support these goals by developing a modular robotics control approach which reduces the time and cost of development by allowing reuse of control system software and uses computer models to improve the safety of remote site cleanup while reducing the time and life cycle costs.
Stimulated reactions on Pt(111) surfaces containing coadsorbates have been probed using laser resonance-enhanced multiphoton ionization (REMPI) spectroscopy of the neutral products. In particular, the electron stimulated dissociation products of NO{sub 2}(a) coadsorbed with up to 0.75 ML of atomic O on Pt(111) has been studied. The coadsorbed O causes a large enhancement of the specific dissociation yield, a narrowing of the NO translational energy, a reduction of the NO internal energy, and the release of the O dissociation fragment into the gas phase. Reactive scattering between coadsorbates has also been studied. Specifically, NO{sub 2}(d) production has been observed during electron-beam irradiation of NO coadsorbed with O{sub 2} on Pt(1211). The NO{sub 2}(d) was indirectly observed as NO({upsilon}=5) and O({sup 3}P{sub J}) gas phase photodissociation fragments. We assign NO{sub 2} production to an electron-stimulated surface reaction involving a collision between energetic O atoms and adsorbed NO.
Heat-Pipe reflux receivers have been identified as a desirable interface to couple a Stirling engine with a parabolic dish solar concentrator. The reflux receiver provides power uniformly and nearly isothermally to the engine heater heads while de-coupling the heater head design from the solar absorber surface design. Therefore, the heat pipe reflux receiver allows the receiver and heater head to be independently thermally optimized, leading to high receiver thermal transport efficiency. Dynatherm Corporation designed and fabricated a screen-wick heat-pipe receiver for possible application to the Cummins Power Generation, Inc. first-generation 4 kW{sub e} free-piston dish-Stirling system, which required up to 30 kW{sub t}. The receiver features a composite absorber wick and a homogeneous sponge-wick on the aft dome to provide sodium to the absorber during hot restarts. The screen wick is attached to the absorber dome by spot welds. Refluxing troughs collect the condensate in a cylindrical condenser and return it directly to the absorber surface. The receiver was fabricated and lamp tested to 16 kW{sub t} throughput by Dynatherm. The receiver has been tested on Sandia`s 60 kW{sub t} solar furnace to a throughput power of 27.5 kW{sub t} and vapor space temperature up to 780{degrees}C. Infrared thermography was used to monitor the entire absorber dome for impending dryout while the receiver was tested. The receiver was started using solar input, without the assistance of electrical pre-heaters. The power was extracted with a gas-gap cold-water calorimeter to simulate the operation of a Stirling engine. The receiver design, thermal performance analysis, flux distribution analysis, test results, and post-test analysis are presented. 11 refs.
Nuclear thermal propulsion systems are envisioned as a fast and efficient form of transportation for the exploration of space. Several nuclear reactor concepts have been proposed. This document discusses SAFSIM (System Analysis Flow SIMulator) which is an engineering computer program that allows the fluid mechanic, heat transfer, and reactor dynamic simulation of the entire propulsion system. SAFSIM currently contains three basic physics modules: (1) fluid mechanics, (2) heat transfer, and (3) reactor dynamics. All three modules are coupled to allow the prediction of system performance. The analyst can employ any or all of the physics modules as the problem dictates.
A summary of the plans to test a prestressed concrete containment vessel (PCCV) model to failure is provided in this paper. The test will be conducted as a part of a joint research program between the Nuclear Power Engineering Corporation (NUPEC), the United States Nuclear Regulatory Commission (NRC), and Sandia National Laboratories (SNL). The containment model will be a scaled representation of a PCCV for a pressurized water reactor (PWR). During the test, the model will be slowly pressurized internally until failure of the containment pressure boundary occurs. The objectives of the test are to measure the failure pressure, to observe the mode of failure, and to record the containment structural response up to failure. Pre- and posttest analyses will be conducted to forecast and evaluate the test results. Based on these results, a validated method for evaluating the structural behavior of an actual PWR PCCV will be developed. The concepts to design the PCCV model are also described in the paper.
The transient transmission of laser activity cavity materials has been measured when they are subjected to 20 ms, fat, and nominal $3 nuclear radiation pulses from Sandia National Laboratories ACRR reactor. Infrasil and 7940 fused silica, and AR and high reflectance coatings have been transient tested at 1.06, 1.73, and 2.03 microns for gamma doses ranging from 0.3 to 0.65 Mrad and neutron fluences ranging from 4.0 to 1.5 10{sup 14} n/cm{sup 2}. pulse widths range from 12 to 250 ms. Transient absorption in 7940 silica and the AR coatings is less than the noise for the conditions of this experiment. At the wavelengths listed above the upper bound for the absorption coefficient of 17940 is 0.00158 cm{sup {minus}1} for single pulse operation. The reflectivity of the HR coating does not change when it is irradiated. Infrasil has both a transient and a permanent induced absorption when it is subjected to radiation. For single pulse operation the absorption coefficients at 1.06, 1.73, and 2.03 microns are 0.0115, 0.0026, and 0.0039 cm{sup {minus}1}, respectively.
The Naval Surface Weapons Laboratory has constructed a small electrical subsystem for the purpose of evaluating electrical upset from various electromagnetic sources. The subsystem consists of three boxes, two of which are intended to be illuminated by electromagnetic waves. The two illuminated boxes are connected by two unshielded cable bundles. The goal of the Navy test series is to expose the subsystem to electromagnetic illumination from several different types of excitation, document upset levels, and compare the results. Before its arrival at Sandia National Laboratories (SNL) the system was illuminated in a mode stirred chamber and in an anechoic chamber. This effort was a continuation of that test program. The Sandia tests involved the test methodology referred to as bulk current injection (BCI). Because this is a poorly-shielded, multiple-aperture system, the method was not expected to compare closely to the other test methods. The test results show that. The BCI test methodology is a useful test technique for a subset of limited aperture systems; the methodology will produce incorrect answers when used improperly on complex systems; the methodology can produce accurate answers on simple systems with a well-controlled electromagnetic topology. This is a preliminary study and the results should be interpreted carefully.
This report describes how small threaded fasteners should be used in threaded connections. Considerable test experience gives many insights into how small threaded fasteners should be used. The test evidence is summarized in this report. The test methods and procedures are described for tension tests to determine strength and ductility. Small threaded fasteners have been used successfully for many years in Sandia applications. Problems have been encountered in manufacturing parts using three fasteners. This report addresses these manufacturing problems and offers recommendations in five areas: (1) design and layout of threaded connections, (2) required depths for tapped holes, (3) characteristics of mating (clamped) surfaces, (4) tensile strength testing procedures and lengths of engagement needed to achieve the full tensile strength of these small fasteners, and (5) installation procedures. 15 refs.
This document serves as the proceedings for the annual project review meeting held by Sandia National Laboratories` Photovoltaic Technology and Photovoltaic Evaluation Departments. It contains information supplied by organizations making presentations at the meeting, which was held July 14--15, 1992 at the Sheraton Old Town Hotel in Albuquerque, New Mexico. Overview sessions covered the Department of Energy (DOE) program, including those at Sandia and the National Renewable Energy Laboratory (NREL), and non-DOE programs, including the EPRI concentrator collector program, The Japanese crystalline silicon program, and some concentrating photovoltaic activities in Europe. Additional sessions included papers on Sandia`s Photovoltaic Device Fabrication Laboratory`s collaborative research, cell processing research, the activities of the participants in the Concentrator Initiative Program, and photovoltaic technology evaluation at Sandia and NREL.
Laser ablation studies of copper oxide using fiber optics to deliver the radiation have been made. A tapered fiber with a 600 micron input and a 200 micron output is used. For continuous operation the damage threshold at the input end is observed to be 2.5 mJ. The Dektak traces indicate the output beem is spatially uniform.
The purification of pyrite (FeS{sub 2}) used in Li-alloy/FeS{sub 2} thermal batteries by the physical process of flotation was evaluated for reduction of the quartz impurity. The process was compared to the standard process of leaching with concentrated hydrofluoric acid. Flotation was an attractive alternative because it avoided many of the safety and environmental concerns posed by the use of concentrated HF. The effects of particle size and initial purity of the pyrite feed material upon the final purity and yield of the product concentrate were examined for batch sizes from 3.5 kg to 921 kg. Feed materials as coarse as 8 mm and as fine as -325 mesh were treated; the coarse pyrite was ground wet in a rod mill or dry in a vibratory mill to -230 mesh prior to flotation. Both the HF-leached and the flotation-treated pyrite were leached with HCI (1:1 v/v) to remove acid-soluble impurities. The flotation-purified pyrite concentrates were formulated into catholytes; their electrochemical performance was evaluated in both single cells and 5-cell batteries for comparison to data generated under the same discharge conditions for catholytes formulated with HF/HCI-purified pyrite.
Diethyltoluenediamine (DETDA) (Ethyl Corp.`s Ethacure 100) was evaluated as a curing agent to replace methylenedianiline (MDA) (Shell`s Agent Z), which is a suspected carcinogen. Shell Z and Ethacure 100 are used to cure Epon 828 epoxy resin for encapsulation of headers for thermal batteries at Sandia. The physical properties of the alumina-filled epoxies cured with Shell Z and Ethacure 100 were characterized to determine if the material strengths were comparable. The study also included epoxies that were aged at 130{degrees}C for one month, to simulate storage at 40{degrees}C for 25 years. Properties that were measured included tensile strength, elastic modulus, shear strength, butt tensile strength, and elongation. The. specific heats of the alumina-filled epoxies were measured for use in thermal-modeling programs for thermal batteries. Batteries built with the Ethacure 100-cured epoxy encapsulation were aged for up to one year at 74{degrees}C and were subjected to severe (1,800 g/50 ms) lateral shock to test the adhesion to the stainless steel header.
Preliminary experiments on the transmission properties of optical fibers exposed to nuclear radiations has been performed. Three wavelengths, 400, 1730 and 2030 nm, were observed for silica fibers. The long term goal of this effort is to develop a method using fiber optics to determine transmission and reflection properties of laser cavity components while being exposed to nuclear radiations. 5 refs.
The aqueous concentration of a radionuclide is one factor that determines the rate at which the radionuclide might be transported away from a nuclear waste repository should a repository breach occur. This study documents research examining the solubility of plutonium in a brine composition of interest for performance assessment for the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico. Solutions starting with five different forms of plutonium, Pu(III), Pu(IV), Pu(IV)-polymer, Pu(V), and Pu(VI), were allowed to equilibrate in a brine with composition similar to that measured from the Culebra Member of the Rustler Formation in the Air Intake Shaft to the WIPP. Nearsteady-state conditions were reached within a year of reaction time. The resulting concentrations represent an upper bound on the amount of plutonium that can remain dissolved in solution under the experimental conditions (e.g., exclusive of colloids) and can thus be transported with the aqueous phase.
The Integral Effects Test (IET) series was designed to investigate the effects of subcompartment structures on direct containment heating (DCH). Scale models of the Zion reactor pressure vessel (RPV), cavity, instrument tunnel, and subcompartment structures were constructed in the Surtsey Test Facility at Sandia National Laboratories. The RPV was modelled with a melt generator that consisted of a steel pressure barrier, a cast MgO crucible, and a thin steel inner liner. The melt generator/crucible had a hemispherical bottom head containing a graphite limiter plate with a 4 cm exit hole to simulate the ablated hole in the RPV bottom head that would be formed by tube ejection in a high pressure melt ejection (HPME) accident. The reactor cavity model contained an amount of water (3.48 kg) that was scaled to condensate levels in the Zion plant. Iron oxide, aluminum, chromium thermite (43 kg) was used to simulate molten corium. The driving gas was 440 g{center_dot}moles of steam at an initial absolute pressure of 7.1 MPa in IET-1 and 477 g{center_dot}moles of steam at an initial pressure of 6.3 MPa in IET-1R. Steam blowdown entrained debris into the Sorts vessel resulting in a peak pressure increase in Sorts of 98 kPa in IET-1 and 110 kPa in IET-1R. The total debris mass ejected into the Sorts vessel was 43.0 kg in IET-1, compared to 36.2 kg in IET-1R. The Sorts vessel had been previously inerted with N{sub 2}. The total quantity of hydrogen produced by steam/metal reactions was 223 g{center_dot}moles in IET-1 and 252 g{center_dot}moles in IET-1R.
The purpose of this study is to investigate transient pressure loads form hydrogen combustion. Specifically, this study relates pressure loads to variations in mixture and initial conditions, mixture heterogeneities, ignition location, and variations in geometry. This study has shown that initial conditions and variations in mixture have a large effect upon the adiabatic isochoric complete combustion, detonation, and reflected detonation pressures. An inert gas layer between a detonable gas mixture and surface can give rise to reflected pressures higher than in the homogeneous case. A deflagration-to-detonation transition (DDT) event near a surface gives rise to higher reflected pressures, and lower impulses, than if the DDT occurred far from the surface. Edges and corners focus detonation waves, which increases both pressures and impulses over those seen from a normally reflected detonation. The loads at points behind an obstacle is less than the load that would be seen if the obstacle were not there.
The Transportation Systems Center at Sandia Laboratory performs research, development, and implementation of technologies that enhance the safe movement of people, goods, and information. Our focus is on systems engineering. However, we realize that to understand the puzzle, you must also understand the pieces. This brochure describes some of the activities currently underway at the Center and presents the breadth and depth of our capabilities. Please contact the noted, individuals for more, information.
The mission of our Center is to enhance the security, prosperity and well-being of our citizens by the application of a security systems approach incorporating the concepts of protection-in-depth, balance, and cost-effective protection. We will build upon the expertise gained through decades of providing security for the DOE nuclear weapons complex and DoD nuclear weapons storage facilities and solve security problems of national importance. Our mission will be accomplished while: Enhancing our ability to fulfill our role as the lead DOE Laboratory in physical security R&D; enhancing our ability to fulfill our role in nuclear weapons surety; enhancing our ability to respond to security requests from other federal, state,, and local agencies; and providing taxpayers a substantial return on investment, both directly in cost savings and indirectly in leveraged benefits. A brief description of research on security systems is described.
The 34-meter Test Bed is a research-oriented, variable-speed vertical-axis wind turbine located at the USDA Agricultural Research Station in Bushland, Texas. Sandia National Laboratories designed and built this machine to perform research in structural dynamics, aerodynamics, and fatigue. Testing to determine its performance in various wind conditions and rotation rates has been ongoing for over three years. This report documents a broad range of test data and includes comparisons to analytical results.
Mechanical properties of the tuffaceous rocks within Yucca Mountain are needed for near and far-field modeling of the potential nuclear waste repository. If the mechanical properties are significantly anisotropic (i.e., direction-dependent), a more complex model is required. Relevant data from tuffs tested in earlier studies indicate that elastic and strength properties are anisotropic. This scoping study confirms the elastic anisotropy and concludes some tuffs are transversely isotropic. An approach for sampling and testing the rock to determine the magnitude of the anisotropy is proposed.
This report describes an assessment of the long-term performance of a repository system that contains deeply buried highly radioactive waste; the system is assumed to be located at the potential site at Yucca Mountain, Nevada. The study includes an identification of features, events, and processes that might affect the potential repository, a construction of scenarios based on this identification, a selection of models describing these scenarios (including abstraction of appropriate models from detailed models), a selection of probability distributions for the parameters in the models, a stochastic calculation of radionuclide releases for the scenarios, and a derivation of complementary cumulative distribution functions (CCDFs) for the releases. Releases and CCDFs are calculated for four categories of scenarios: aqueous flow (modeling primarily the existing conditions at the site, with allowances for climate change), gaseous flow, basaltic igneous activity, and human intrusion. The study shows that models of complex processes can be abstracted into more simplified representations that preserve the understanding of the processes and produce results consistent with those of more complex models.
Accurate alignment and focus of mirror facets are critical for the integration of concentrators and receivers in many of the low-cost stretched-membrane concentrators currently under development. In this report, the theoretical development of computer software that traces light rays from a source to a facet of a point-focusing solar concentrator and then to a target is given. Examples of approaches for the alignment of faceted point-focusing solar concentrators, which make use of targets generated by this computer program, are also presented.
This review of ongoing research at Sandia National Laboratory in the areas of nuclear weapons development and testing, arms control. As a multiprogram laboratory, their core competencies make special contributions in other areas of national importance. Work on US DOE programs is presented on the following subjects: robots; computers: arms control; nuclear weapons reliability; fusion research; solar energy; semiconductor detectors; radioactive waste management; nuclear explosion detection; and others. The laboratories strategic plan and other management methods are outlined. (GHH)
The efficient operation of a Stirling engine requires the application of a high heat flux to the relatively small area occupied by the heater head tubes. Previous attempts to couple solar energy to Stirling engines generally involved directly illuminating the heater head tubes with concentrated sunlight. In this study, operation of a 75-kW{sub t} sodium reflux pool-boiler solar receiver has been demonstrated and its performance characterized on Sandia's nominal 75-kW{sub t} parabolic-dish concentrator, using a cold-water gas-gap calorimeter to simulate Stirling engine operation. The pool boiler (and more generally liquid-metal reflux receivers) supplies heat to the engine in the form of latent heat released from condensation of the metal vapor on the heater head tubes. The advantages of the pool boiler include uniform tube temperature, leading to longer life and higher temperature available to the engine, and decoupling of the design of the solar absorber from the engine heater head. The two-phase system allows high input thermal flux, reducing the receiver size and losses, therefore improving system efficiency. The receiver thermal efficiency was about 90% when operated at full power and 800{degree}C. Stable sodium boiling was promoted by the addition of 35 equally spaced artificial cavities in the wetted absorber surface. High incipient boiling superheats following cloud transients were suppressed passively by the addition of small amounts of xenon gas to the receiver volume. Stable boiling without excessive incipient boiling superheats was observed under all operating conditions. The receiver developed a leak during performance evaluation, terminating the testing after accumulating about 50 hours on sun. The receiver design is reported here along with test results including transient operations, steady-state performance evaluation, operation at various temperatures, infrared thermography, x-ray studies of the boiling behavior, and a postmortem analysis.
This report describes a hardware implementation of a fast fourier transform (FFT) based real time data compression system. The system is currently configured to compress and analyze airborne vehicle vibration data but it can be utilized for compressing any one- dimensional data stream. The algorithm uses a two-stage process to compress successive stationary time periods of input data. The first stage compresses data by transforming continuous blocks of 2048 points to the frequency domain using Welch's method. The second stage provides further compression by logarithmically averaging adjacent frequency bins of the transformed signal. These compression techniques result in a bandwidth savings from 8:1 to 64:1 per channel compared to strictly analog or digital transmission techniques. The complete technique as well as the hardware used to implement it is described in detail in this report.