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Jump to search filtersA simple description of flow instability with application to a packed bed
A simplified explanation for gas flow instability in parallel heated channels is presented with specific applications to channels containing packed beds of power-producing particles. The explanation captures the basic governing physics of the viscosity-driven instability and hopefully removes some of the misconceptions surrounding this issue. Simple illustrative calculations, steady-state and transient, using the SAFSIM computer program are included in the explanation. The explanation points out that flow instability is common to any and all gas flow systems with parallel heated channels, that the addition of flow resistance to the entrance of a channel mitigates flow instability, and that instabilities do not occur instantaneously.
Six degree of freedom fine motion positioning stage based on magnetic levitation
Arling, R.W.; Kohler, S.M.
The design of a magnetically suspended six degree of freedom positioning system capable of nanometer positioning is presented. The sample holder is controlled in six degrees of freedom (DOF) over 300 micrometers of travel in X, Y and Z directions. A design and control summary, and test results indicating stability and power dissipation are included in the paper. The system is vacuum compatible, uses commercially available materials, and requires minimal assembly and setup.
Concepts for operational period panel seal design at the Waste Isolation Pilot Plant
Concepts for underground panel or drift seals at the Waste Isolation Pilot Plant are developed to satisfy sealing requirements of the operational period. The concepts are divided into two groups. In the ``NOW`` group, design concepts are considered in which a sleeve structure is installed in the panel access immediately after excavation and before waste is emplaced. In the ``LATER`` group, no special measures are taken during excavation or before waste emplacement; the seal is installed at a later date, perhaps up to 35 years after the drift is excavated. Three concepts are presented in both the NOW and LATER groups. A rigid sleeve, a yielding sleeve, and steel rings with inflatable tubes are proposed as NOW concepts. One steel ring concept and two concrete monoliths are proposed for seals emplaced in older drifts. Advantages and disadvantages are listed for each concept. Based on the available information, it appears most feasible to recommend a LATER concept using a concrete monolith as a preferred seal for the operational period. Each concept includes the potential of remedial grout and/or construction of a chamber that could be used for monitoring leakage from a closed panel during the operational period. Supporting in situ demonstrations of elements of the concepts are recommended.
Shock compression properties of silicon carbide
Grady, D.E.; Kipp, M.E.
An investigation of the shock compression and release properties of silicon carbide ceramic has been performed. A series of planar impact experiments has been completed in which stationary target discs of ceramic were struck by plates of either similar ceramic or other appropriate material at velocities up to 2.2 km/s with a propellant gun facility. The particle velocity history at the interface between the back of the target ceramic and a lithium-fluoride window material was measured with laser velocity interferometry (VISAR). Impact stresses achieved in these experiments range between about 10 and 50 GPa. Numerical solutions and analytic methods were used to determine the dynamic compression and release stress-strain behavior of the ceramic. Further analysis of the data was performed to determine dynamic strength and compressibility properties of silicon carbide.
The CAESAR project: Experimental and modeling investigations of methane reforming in a CAtalytically Enhanced Solar Absorption Receiver on a parabolic dish
Muir, J.F.; Hogan Jr., R.E.; Skocypec, R.D.; Buck, R.
A joint US/Federal Republic of Germany (FRG) project has successfully tested a unique solar-driven chemical reactor in the CAtalytically Enhanced Solar Absorption Receiver (CAESAR) experiment. The CAESAR test was a {open_quotes}proof-of-concept{close_quotes} demonstration of carbon-dioxide reforming of methane in a commercial-scale, solar, volumetric receiver/reactor on a parabolic dish concentrator. The CAESAR design; test facility and instrumentation; thermal and chemical tests; and analysis of test results are presented in detail. Numerical models for the absorber and the receiver are developed and predicted performance is compared with test data. Post test analyses to assess the structural condition of the absorber and the effectiveness of the rhodium catalyst are presented. Unresolved technical issues are identified and future development efforts are recommended.
Hydrous metal oxide catalysts for oxidation of hydrocarbons
This report describes work performed at Sandia under a CRADA with Shell Development of Houston, Texas aimed at developing hydrous metal oxide (HMO) catalysts for oxidation of hydrocarbons. Autoxidation as well as selective oxidation of 1-octene was studied in the presence of HMO catalysts based on known oxidation catalysts. The desired reactions were the conversion of olefin to epoxides, alcohols, and ketones, HMOs seem to inhibit autoxidation reactions, perhaps by reacting with peroxides or radicals. Attempts to use HMOs and metal loaded HMOs as epoxidation catalysts were unsuccessful, although their utility for this reaction was not entirely ruled out. Likewise, alcohol formation from olefins in the presence of HMO catalysts was not achieved. However, this work led to the discovery that acidified HMOs can lead to carbocation reactions of hydrocarbons such as cracking. An HMO catalyst containing Rh and Cu that promotes the reaction of {alpha}-olefins with oxygen to form methyl ketones was identified. Although the activity of the catalyst is relatively low and isomerization reactions of the olefin simultaneously occur, results indicate that these problems may be addressed by eliminating mass transfer limitations. Other suggestions for improving the catalyst are also made. 57 refs.
Mission hazard assessment for STARS Mission 1 (M1) in the Marshall Islands area
Outka, D.E.; Lafarge, R.A.
A mission hazard assessment has been performed for the Strategic Target System Mission 1 (known as STARS M1) for hazards due to potential debris impact in the Marshall Islands area. The work was performed at Sandia National Laboratories as a result of discussion with Kwajalein Missile Range (KMR) safety officers. The STARS M1 rocket will be launched from the Kauai Test Facility (KTF), Hawaii, and deliver two payloads to within the viewing range of sensors located on the Kwajalein Atoll. The purpose of this work has been to estimate upper bounds for expected casualty rates and impact probability or the Marshall Islands areas which adjoin the STARS M1 instantaneous impact point (IIP) trace. This report documents the methodology and results of the analysis.
Fire hazards analysis for the Center for National Security and Arms Control (CNSAC) Facility
This Fire Hazards Analysis is sponsored by Plant Engineering and is prepared to support the Safety Assessment for the CNSAC Facility. This is a preliminary fire hazards analysis of a yet to be constructed facility and is based upon the current building design and the current understanding of the potential occupancy hazards. The governing occupancy for this building is personnel offices. The CNSAC facility will be dedicated primarily to two activities: (1) arms control and verification technology and (2) intelligence. This report supplements the Safety Assessment for the CNSAC facility and follows the guidance of DOE Memorandum EH-31.3 and meets the objectives of paragraph 4 of DOE Order 5480.7A, ``Fire Protection.`` This analysis demonstrates that under ``worst case`` assumptions a fire in the CNSAC facility will result in consequences which are below DOE offsite guidelines for accident conditions. This report is based upon preliminary design information and any major changes to the building design may require additional analyses.
Conceptual plan: Two-Phase Flow Laboratory Program for the Waste Isolation Pilot Plant
The Salado Two-Phase Flow Laboratory Program was established to address concerns regarding two-phase flow properties and to provide WIPP-specific, geologically consistent experimental data to develop more appropriate correlations for Salado rock to replace those currently used in Performance Assessment models. Researchers in Sandia`s Fluid Flow and Transport Department originally identified and emphasized the need for laboratory measurements of Salado threshold pressure and relative permeability. The program expanded to include the measurement of capillary pressure, rock compressibility, porosity, and intrinsic permeability and the assessment of core damage. Sensitivity analyses identified the anhydrite interbed layers as the most likely path for the dissipation of waste-generated gas from waste-storage rooms because of their relatively high permeability. Due to this the program will initially focus on the anhydrite interbed material. The program may expand to include similar rock and flow measurements on other WIPP materials including impure halite, pure halite, and backfill and seal materials. This conceptual plan presents the scope, objectives, and historical documentation of the development of the Salado Two-Phase Flow Program through January 1993. Potential laboratory techniques for assessing core damage and measuring porosity, rock compressibility, capillary and threshold pressure, permeability as a function of stress, and relative permeability are discussed. Details of actual test designs, test procedures, and data analysis are not included in this report, but will be included in the Salado Two-Phase Flow Laboratory Program Test Plan pending the results of experimental and other scoping activities in FY93.
Sandia equation of state data base: seslan File
Kerley, G.I.; Christian-Frear, T.L.
Sandia National Laboratories maintains several libraries of equation of state tables, in a modified Sesame format, for use in hydrocode calculations and other applications. This report discusses one of those libraries, the seslan file, which contains 78 tables from the Los Alamos equation of state library. Minor changes have been made to these tables, making them more convenient for code users and reducing numerical difficulties that occasionally arise in hydrocode calculations.
Burnup Credit Validation of SCALE-4 Using Light-Water-Reactor Criticals
Bowman, S.M.; Hermann, O.W.; Brady, M.C.
The ANSI/ANS 8.1 criticality safety standard recommends validation and benchmarking of the calculational methods used in evaluating criticality safety limits for away-from-reactor applications. The lack of critical experiments with burned light-water reactor (LWR) fuel in racks or in casks necessitates the validation of burnup credit methods by comparison with LWR core criticals. These benchmarks are relevant because they test a methodology`s ability to predict spent fuel isotopic and to evaluate the reactivity effects of heterogeneities and strong absorbers. Data are available to perform analyses at precise state points. As part of the Burnup Credit Analysis Verification (BCAV) Task, the U.S. Department of Energy has sponsored analysis of selected reactor core critical configurations from commercial pressurized-water-reactors (PWRs). The initial analysis methodology used the SCALE-4 code system to analyze a set of reactor critical configurations from Virginia Power`s Slurry and North Anna reactors. However, the analysis procedure was complex and included the calculation of lumped fission products. The methodology has since been revised to simplify both the data requirements and the calculational procedure for the criticality analyst. This revised methodology is validated here by a comparison with three reactor critical configurations from Tennessee Valley Authority`s Sequoyah Unit 2 Cycle 3 and two from Virginia Power`s Slurry Unit 1 Cycle 2.
The Mobil Integrated C{sup 3} (command control and communications) and Security System
Eras, A.; Brown, R.D.
The current political and economic situations suggest that significant reductions of nuclear forces outside the US will continue. This implies that in times of crisis the rapid deployment of nuclear weapons into a theater may be required. This paper describes a proposed Mobile Integrated C{sup 3} and Security System (MICSS). The MICSS, together with associated personnel, could satisfy the command and control and security requirements of a deployed nuclear operation. Rapid deployment poses unique nuclear weapon surety difficulties that must be overcome for the operation to be effective and survivable. The MICSS must be portable, reliable, limited in size, and easily emplaced to facilitate movement, reduce the possibility of detection, and minimize manpower requirements. The MICSS will be based on existing technology. Sandia has designed prototype mobile command centers for the military. These command centers are based on an approach that stresses modularity, standards, and the use of an open architecture. Radio, telephone, satellite communications, communication security, and global positioning system equipment has been successfully integrated into the command centers. Sandia is also supporting the development of portable security systems for the military. These systems are rapidly deployable and mission flexible and are capable of intrusion detection, area and alarm display, night assessment, and wireless sensor communications. This paper is organized as follows: Background information about the prototype mobile command centers will be presented first. Background information about portable security systems concepts will then be given. Next, an integrated communications and security system will be presented, and finally, the design and status of a prototype MICSS will be described.
Micro-radiosurgery: a new concept for radiotherapy based upon low energy, ion-induced nuclear reactions
Nuclear Inst. and Methods in Physics Research, B
Traditionally, proton radiotherapy has required the use of high energy proton beams (50-200 MeV) which can penetrate into a patient's body to the site of a tumor that is to be destroyed through irradiation. However, substantial damage is still done to healthy tissue along the path of the incident proton beam, as much as 30% of that done at the tumor site. We propose a new concept for the production and delivery of energetic protons for use in medical radiotherapy, based upon the fact that low energy, ion-induced nuclear reactions can produce radiation products suitable for use in radiotherapy applications. By employing specially fabricated "conduit needles" to deliver beams of energetic ions to selected target materials plugging the end of the needle, ion beam-induced nuclear reactions can be generated at the needle tip, emitting reaction-specific radiation products directly at the tumor site. In this paper, we show that the 13.6 MeV protons produced by the d(3He, p)4He nuclear reaction can deliver a lethal dose (7 krad) of radiation to a 4.4 mm diameter sphere of tissue in only 30 s using a 1 μA, 800 keV 3He ion beam. If also proven clinically feasible, the use of low energy, ion-induced nuclear reactions would allow the utilization of relatively inexpensive, compact, low energy ion accelerators for proton radiotherapy and minimize unintended radiation damage to healthy tissue by providing much greater precision in controlling the irradiated volume. © 1993.
Propagation of transient signals from a spherical source in a half-space with surface layers
Norwood, F.R.
The title problem is of particular interest for the analysis of seismic signals arising from underground nuclear explosions. Previous attempts at the solution have indicated that, although cylindrical symmetry exists, conventional methods cannot be applied because of the existence of plane and spherical boundaries. The present paper develops a ray-grouping technique for finding the solution to the title problem. This technique allows the separation of the problem into a series of canonical problems. Each such problem deals with a given boundary condition (e.g., continuity conditions at a material interface). Using this technique, one may follow waves along ray paths. It is easy to identify, after n reflections, (a) rays which arrive simultaneously at a given point and (b) the terms in the solution which need to be included at a given time. It is important to note that a cylindrical coordinate system is not employed, even though the problem is axially symmetric. Instead, the equations are carefully transformed making it possible to use a Cartesian coordinate system. This results in a spectral representation of the solution in terms of algebraic expressions in lieu of Bessel functions.
Thermal coating development for impulse drying
Journal of Thermal Spray Technology
A plasma-sprayed coating has been developed for the heated surface of rolls used in a new energy-efficient paper drying process, known as"Impulse Drying," which could save the US paper industry an estimated $800 million annually in reduced energy costs. Because impulse drying rolls operate at substantially higher surface temperatures than conventional drying rolls, the thermal properties of the roll surface must be carefully tailored to control energy transfer to the paper and thus prevent sheet delamination or other undesirable effects. To meet this requirement, a plasma-sprayed thermal barrier coating has been developed to control thermal mass, heat transfer, and steam infiltration. A coated test platen significantly outperformed a comparable uncoated steel platen in preliminary experiments with a heavyweight grade of paper on a laboratory-scale impulse drying simulator. Based on these results, the coating was then tested on the roll of a pilot-scale impulse dryer. Compared to conventional wet pressing, linerboard that was impulse dried with the coated test roll showed marked improvements in water removal as well as improved physical properties, such as density and specific elastic modulus. The successful prototype coating design has three plasma-sprayed layers that are deposited sequentially: a nickel alloy bond coat, a thick, 17% porous zirconia thermal barrier, and a thin, 5 to 7% porous zirconia top coat. © 1993 ASM International.
Some parametric flow analyses of a particle bed fuel element
Parametric calculations are performed, using the SAFSIM computer program, to investigate the fluid mechanics and heat transfer performance of a particle bed fuel element. Both steady-state and transient calculations are included, addressing such issues as flow stability, reduced thrust operation, transpiration drag, coolant conductivity enhancement, flow maldistributions, decay heat removal, flow perturbations, and pulse cooling. The calculations demonstrate the dependence of the predicted results on the modeling assumptions and thus provide guidance as to where further experimental and computational investigations are needed. The calculations also demonstrate that both flow instability and flow maldistribution in the fuel element are important phenomena. Furthermore, results are encouraging that geometric design changes to the element can significantly reduce problems related to these phenomena, allowing improved performance over a wide range of element power densities and flow rates. Such design changes will help to maximize the operational efficiency of space propulsion reactors employing particle bed fuel element technology. Finally, the results demonstrate that SAFSIM is a valuable engineering tool for performing quick and inexpensive parametric simulations addressing complex flow problems.
Metallurgical evaluation of SRAM II/SRAM A programmer base plates
Ten MC4073/4369 programmer base plates were analyzed. This component, a programmer base plate for the SRAM II (and later the SRAM A), is specified as a Grade C quality casting made of aluminum Alloy A356, heat treated to the T6 condition. A concern was expressed regarding the choice of an A356 casting for this application, given the complexity and severity of the loading environment. Preliminary tests and analyses suggested that the design was adequate, but noted the uncertainty involved in a number of their underlying assumptions. The uncertainty was compounded by the discovery that the casting used in the original series of mechanical tests failed. In this investigation, several production castings were examined and found to be of a quality superior to that required under current specifications. Their defect content and microstructure were studied and compared with published data to establish a mechanical property data base. The data base was supplemented with a series of X-direction static tests, which characterized the loading environment and measured the overall casting performance. It was found that the mechanical properties of the supplied castings were adequate for the anticipated X-direction loading environment, but the component is not over-designed. The established data base further indicates that a reduction in casting quality to the allowable level could result in failure of the component. Recommendations were made including (1) change the component specification to require higher casting quality in highly stressed areas, (2) supplement the inspection procedures to ensure adequate quality in critical regions, (3) alter the component design to reduce the stress levels in the mounting feet, (4) substitute a modified A356 alloy to improve the mechanical properties and their consistency, and (5) more thoroughly establish a data base for the mechanical property consequences of levels and configurations of casting defects.
Maintenance manual for the Beneficial Uses Shipping System cask. Revision 1
Bronowski, D.R.; Yoshimura, H.R.
This document is the Maintenance Manual for the Beneficial Uses Shipping System (BUSS) cask. These instructions address requirements for maintenance, inspection, testing, and repair, supplementing general information found in the BUSS Safety Analysis Report for Packaging (SARP), SAND 83-0698. Use of the BUSS cask is authorized by the Department of Energy (DOE) and the Nuclear Regulatory Commission (NRC) for the shipment of special form cesium chloride or strontium flouride capsules.
Programmer`s manual for CAMCON: Compliance Assessment Methodology CONtroller
CAMCON, the Compliance Assessment Methodology CONtroller, is an analysis system that assists in assessing the compliance of the Waste Isolation Pilot Plant (WIPP) with applicable long-term regulations of the US Environmental Protection Agency, including Subpart B of the Environmental Standards for the Management and Disposal of spent Nuclear Fuel, High-Level and Transuranic Radioactive Wastes, 40 CFR 191 and 40CFR268.6, which is the portion of the Land Disposal Restrictions implementing the Resource, Conservative, and Recovery Act of 1976, as amended that states the conditions for disposal of hazardous chemical wastes. This manual provides an architectural overview of the CAMCON system. Furthermore this manual presents guidelines and presents suggestions for programmers developing the many different types of software necessary to investigate various events and physical processes of the WIPP. These guidelines include user interface requirements, minimum quality assurance requirements, coding style suggestions, and the use of numerous software libraries developed specifically for or adapted for the CAMCON system.
Initial field testing definition of subsurface sealing and backfilling tests in unsaturated tuff; Yucca Mountain Site Characterization Project
Fernandez, J.A.; Case, J.B.; Tyburski, J.R.
This report contains an initial definition of the field tests proposed for the Yucca Mountain Project repository sealing program. The tests are intended to resolve various performance and emplacement concerns. Examples of concerns to be addressed include achieving selected hydrologic and structural requirements for seals, removing portions of the shaft liner, excavating keyways, emplacing cementitious and earthen seals, reducing the impact of fines on the hydraulic conductivity of fractures, efficient grouting of fracture zones, sealing of exploratory boreholes, and controlling the flow of water by using engineered designs. Ten discrete tests are proposed to address these and other concerns. These tests are divided into two groups: Seal component tests and performance confirmation tests. The seal component tests are thorough small-scale in situ tests, the intermediate-scale borehole seal tests, the fracture grouting tests, the surface backfill tests, and the grouted rock mass tests. The seal system tests are the seepage control tests, the backfill tests, the bulkhead test in the Calico Hills unit, the large-scale shaft seal and shaft fill tests, and the remote borehole sealing tests. The tests are proposed to be performed in six discrete areas, including welded and non-welded environments, primarily located outside the potential repository area. The final selection of sealing tests will depend on the nature of the geologic and hydrologic conditions encountered during the development of the Exploratory Studies Facility and detailed numerical analyses. Tests are likely to be performed both before and after License Application.
Waste component recycle, treatment, and disposal integrated demonstration (WeDID) nuclear weapon dismantlement activities
Wheelis, W.T.
One of the drivers in the dismantlement and disposal of nuclear weapon components is Envirorunental Protection Agency (EPA) guidelines. The primary regulatory driver for these components is the Resource Conservation Recovery Act (RCRA). Nuclear weapon components are heterogeneous and contain a number of hazardous materials including heavy metals, PCB`S, selfcontained explosives, radioactive materials, gas-filled tubes, etc. The Waste Component Recycle, Treatment, Disposal and Integrated Demonstration (WeDID) is a Department of Energy (DOE) Environmental Restoration and Waste Management (ERWM) sponsored program. It also supports DOE Defense Program (DP) dismantlement activities. The goal of WeDID is to demonstrate the end-to-end disposal process for Sandia National Laboratories designed nuclear weapon components. One of the primary objectives of WeDID is to develop and demonstrate advanced system treatment technologies that will allow DOE to continue dismantlement and disposal unhindered even as environmental regulations become more stringent. WeDID is also demonstrating waste minimization techniques by recycling a significant weight percentage of the bulk/precious metals found in weapon components and by destroying the organic materials typically found in these components. WeDID is concentrating on demonstrating technologies that are regulatory compliant, are cost effective, technologically robust, and are near-term to ensure the support of DOE dismantlement time lines. The waste minimization technologies being demonstrated by WeDID are cross cutting and should be able to support a number of ERWM programs.
Interactive Collaborative Environments (ICE) in the design to manufacturing process
Interactive Collaborative Environments (ICE) technologies allow teames at separate locations to work concurrently on joint problem solving. Examples of ICE use include engineers simultaneously viewing and manipulating the same CAD application to discuss design/production changes and trade-offs. This concept was demonstrated in March of 1992 between AT&T, Shreveport Works and Holmdel. In May 1992, Sandia National Laboratories demonstrated a platform independent version of application sharing code using the workstations and application software available at AT&T, Shreveport Works. AT&T and Sandia are currently negotiating future work agreements. In addition, Sandia has provided demonstrations and created pilot project links for internal Sandia use, and for communication with other facilities, e.g. Los Alamos National Laboratories and Sandia, California location. ICE can also be used to link up suppliers and customers, even in different companies. Anywhere team members are separated geographically, or even between building and facilities at a particular site, ICE can improve remote problem solving, cutting down on delays and miscommunication flascoes.
The detection of organosphosphonates by polymer films on a surface acoustic wave device and a micromirror fiberoptic sensor
Applied Biochemistry and Biotechnology
There is a need for sensitive detection of organophosphonates by inexpensive, portable instruments. Two kinds of chemical sensors, based on surface acoustic wave (SAW) devices and fiberoptic micromirrors, show promise for such sensing systems. Chemically sensitive coatings are required for detection, and data for thin films of the polymer polysiloxane are reported for both kinds of physical transducers. Both kinds of sensors are shown to be capable of detecting concentrations of diisopropylmethylphosphonate (DIMP) down to 1 ppm. © 1993 Humana Press Inc.
Energy dispersive x-ray spectrometers in ultrahigh vacuum environments
The combination of an energy dispersive x-ray spectrometer (EDS) with the ultrahigh vacuum environment of many modern electron microscopes requires the spectrometer designer to take extra precautions and presents the microscopist with the additional option of utilizing windowless spectrometers for light element detection while not worrying about contamination of the detector. UHV is generally defined as a pressure of better than 10{sup {minus}7} Pa and is necessary to prevent specimen modification by the components of the vacuum. UHV may also be defined as an environment in which the time to form a monolayer on the specimen is equal to or longer than the usual time for a laboratory measurement. This report examines performance of energy dispersion x-ray spectrometers in UHV.