Sealing methods and materials currently used in salt and potash industries were surveyed to determine if systems analogous to the shaft seal design proposed for the Waste Isolation Pilot Plant (WIPP) exist. Emphasis was first given to concrete and then expanded to include other materials. Representative case studies could provide useful design, construction, and performance information for development of the WIPP shaft seal system design. This report contains a summary of engineering and construction details of various sealing methods used by mining industries for bulkheads and shaft liners. Industrial experience, as determined from site visits and literature reviews, provides few examples of bulkheads built in salt and potash mines for control of water. Sealing experiences representing site-specific conditions often have little engineering design to back up the methods employed and even less quantitative evaluation of seal performance. Cases examined include successes and failures, and both contribute to a database of experiences. Mass salt-saturated concrete placement under ground was accomplished under several varied conditions. Information derived from this database has been used to assess the performance of concrete as a seal material. Concrete appears to be a robust material with successes in several case studies. 42 refs.
This report presents the results of instrumentation measurements and observations made during construction of the North Ramp Starter Tunnel (NRST) of the Exploratory Studies Facility (ESF). The information in this report was developed as part of the Design Verification Study, Section 8.3.1.15.1.8 of the Yucca Mountain Site Characterization Plan (DOE 1988). The ESF is being constructed by the US Department of Energy (DOE) to evaluate the feasibility of locating a potential high-level nuclear waste repository on lands within and adjacent to the Nevada Test Site (NTS), Nye County, Nevada. The Design Verification Studies are performed to collect information during construction of the ESF that will be useful for design and construction of the potential repository. Four experiments make up the Design Verification Study: Evaluation of Mining Methods, Monitoring Drift Stability, Monitoring of Ground Support Systems, and The Air Quality and Ventilation Experiment. This report describes Sandia National Laboratories` (SNL) efforts in the first three of these experiments in the NRST.
This international directory of more than 500 photovoltaic-related manufacturers is intended to guide potential users of photovoltaics to sources for systems and their components. Two indexes help the user to locate firms and materials. A glossary describes equipment and terminology commonly used in the photovoltaic industry.
Sandia National Laboratories and Industrial Solar Technology are cost-sharing development of advanced parabolic trough technology. As part of this effort, several configurations of an IST solar collector were tested to determine the collector efficiency and thermal losses with black chrome and black nickel receiver selective coatings, combined with aluminized film and silver film reflectors, using standard Pyrex{reg_sign} and anti-reflective coated Pyrex{reg_sign} glass receiver envelopes. The development effort has been successful, producing an advanced collector with 77% optical efficiency, using silver-film reflectors, a black nickel receiver coating, and a solgel anti-reflective glass receiver envelope. For each receiver configuration, performance equations were empirically derived relating collector efficiency and thermal losses to the operating temperature. Finally, equations were derived showing collector performance as a function of input insolation value, incident angle, and operating temperature.
Solar Kinetics, Inc., has been developing a point-focus concentrating photovoltaic module and tracker system under contract to Sandia National Laboratories. The primary focus of the contract was to achieve a module design that was manufacturable and passed Sandia`s environmental testing. Nine modules of two variations were assembled, tested, and characterized in Phase 1, and results of these tests were promising, with module efficiency approaching the theoretical limit achievable with the components used. The module efficiency was 11.9% at a solar irradiance of 850 W/sq m and an extrapolated cell temperature of 25 C. Improvements in module performance are anticipated as cell efficiencies meet their expectations. A 2-kW tracker and controller accommodating 20 modules was designed, built, installed, and operated at Solar Kinetics` test site. The drive used many commercially available components in an innovative arrangement to reduce cost and increase reliability. Backlash and bearing play were controlled by use of preloaded, low slip-stick, synthetic slide bearings. The controller design used a standard industrial programmable logic controller to perform ephemeris calculations, operate the actuators, and monitor encoders.
The objective of the workshop was to promote discussions between experts and research managers on developing approaches for assessing the impact of DOE`s basic energy research upon the energy mission, applied research, technology transfer, the economy, and society. The purpose of this impact assessment is to demonstrate results and improve ER research programs in this era when basic research is expected to meet changing national economic and social goals. The questions addressed were: (1) By what criteria and metrics does Energy Research measure performance and evaluate its impact on the DOE mission and society while maintaining an environment that fosters basic research? (2) What combination of evaluation methods best applies to assessing the performance and impact of OBES basic research? The focus will be upon the following methods: Case studies, User surveys, Citation analysis, TRACES approach, Return on DOE investment (ROI)/Econometrics, and Expert panels. (3) What combination of methods and specific rules of thumb can be applied to capture impacts along the spectrum from basic research to products and societal impacts?
The specific contact resistivity of Cu with ({alpha} + {beta})-Ta, TiN, {alpha}-W, and amorphous-Ta{sub 36}Si{sub 14}N{sub 50} barrier films is measured using a novel four-point-probe approach. Geometrically, the test structures consist of colinear sets of W-plugs to act as current and voltage probes that contact the bottom of a planar Cu/barrier/Cu stack. Underlying Al interconnects link the plugs to the current source and voltmeter. The center-to-center distance of the probes ranges from 3 to 200 {micro}m. Using a relation developed by Vu et al., a contact resistivity of roughly 7 {times} 10{sup {minus}9} {Omega} cm{sup 2} is obtained for all tested barrier/Cu combinations. By reflective-mode small-angle X-ray scattering, the similarity in contact resistivity among the barrier films may be related to interfacial impurities absorbed from the deposition process.
Fine-grained and coarse-grained aluminas containing either equiaxed or elongated grain structures were fabricated from commercial-purity and high-purity alumina powders. Compared to the high-purity aluminas, the commercial-purity aluminas having a coarse grain size and elongated grain structures exhibited significantly more pronounced flaw tolerance and T-curve behavior. T-curve behavior determined from indentation strength tests suggested that only the coarse- grained, elongated-grain alumina had a T-curve sufficient to cause stable crack extension prior to failure, a requirement for any observable improvement in reliability. In the high-purity aluminas as well as the fine-grained commercial-purity aluminas, however, it is likely that little or no stable extension occurs prior failure, suggesting that strength in these materials is dependent on the critical flaw size. Strength tests on polished specimens showed the commercial-purity aluminas had a lower means strength than the high- purity aluminas and the coarse-grained aluminas exhibited a lower mean strength compared to the fine-grained aluminas. An analysis of the mean strength versus grain size revealed that the differences in critical flaw size alone could not account for the differences in mean strength. Instead, a combination of changes in flaw size as well as T-curve behavior were shown to be responsible for the differences in strength and flaw tolerance. T-curve behavior was also found to have a profound influence on the strength variability of alumina. For example, the Weibull modulus for the coarse-grained, commercial- purity alumina was almost twice that of the fine-grained, high-purity material. Tests with indented specimens conclusively demonstrated that improvements in reliability in these materials are not due solely to changes in the critical flaw size distribution but rather a combination of flaw size distribution and T-curve behavior.
The dynamic performance of a 250 Hz resonant plate shock system which simulates pyrotechnic shock environments on micro-electrical components is evaluated. A series of experiments recording strain rate histories and acceleration time histories at several plate locations were conducted. This empirical data is used to compare the analytical results obtained from a finite element based numerical simulation. The comparison revealed a good correlation between experimental and analytical results.
Simulations of soil-heated vapor extraction have been performed to evaluate the NAPL removal performance as a function of borehole vacuum. The possibility of loss of NAPL containment, or NAPL migration into the unheated soil, is also evaluated in the simulations. A practical warning sign indicating migration of NAPL into the unheated zone is discussed.
Hydrogen is readily incorporated into GaN and related alloys during wet and dry etching, chemical vapor deposition of dielectric overlayers, boiling in water and other process steps, in addition to its effects during MOCVD or MOMBE growth. The hydrogen is bound at defects or impurities and passivates their electrical activity. Reactivation occurs at 450-550{degrees}C, but evolution from the crystal requires much higher temperatures ({ge} 800{degrees}C).
We have studied the formation of Fe clusters in inverse micelles. We have characterized the clusters with respect to size with transmission electron microscopy (TEM) and with respect to chemical composition with Mossbauer spectroscopy, electron diffraction, and x-ray photoelectron spectroscopy (XPS). In addition, we have tested these iron based clusters for catalytic activity in a model hydrogenolysis reaction. The formation of ultra-small metal particles is of particular interest in the area of chemical catalysis. The clusters are high surface area, highly dispersed, unsupported materials. In addition, catalytic enhancement due to unique material properties (i.e. quantum size effects) is possible. Metal clusters prepared by a number of techniques have been studied as potential catalysts. Reactant adsorption and the reactivity in various processes depends strongly on particle size. We are studying iron clusters as potential catalysts in hydrogenation reactions, Fischer-Tropsch synthesis, and coal liquefaction.
We have refined the structures for YBa{sub 2}Cu{sub 2.94}Ni{sub 0.06}O{sub y} (2% Ni) and YBa{sub 2}Cu{sub 2.80}Ni{sub 0.20}O{sub y} (6.67% Ni) at y {approximately} 6.95 and y {approximately} 6.5 contents. Oxygen was reduced by two independent methods: quenching from 690{degrees}C and oxygen gettering at 450{degrees}C. Cu-0 bond lengths were calculated based on Rietveld structure refinements for the various samples; they indicate the likely occupancy of Ni in the plane (Cu2) site of the 123 superconductor.
Cathodoluminescent (CL) phosphors with improved low-voltage characteristics are needed for use in emissive flat panel displays. Conventional high-temperature methods for phosphor synthesis yield large polycrystalline grains that must be pulverized prior to screen deposition. Grinding has been implicated in reducing phosphor efficiency by causing surface contamination and defects. Hydrothermal synthesis has been used to improve the quality of ceramic powders by producing fine, well-formed crystallites without grinding. Two green-emitting phosphors, Y{sub 3}Al{sub 5}O{sub 12}:Tb (YAG:Tb) and NaY(WO{sub 4}){sub 2}:Tb, were used to test the effects of hydrothermal. synthesis on grain size and morphology, and on low-voltage CL properties. YAG:Th prepared hydrothermally consisted of submicron crystallites with a typical garnet habit. The CL efficiency of hydrothermally synthesized YAG:Tb (3 lm/W at 800 V) was comparable to that of equivalent YAG:Tb compositions prepared via high-temperature solid state reaction. In comparison, CL intensities of Gd{sub 3}Ga{sub 5}O{sub l2}:Tb were slightly better (3.5 lm/W at 800 V), while those of NaY(WO{sub 4}){sub 2}:Tb were approximately 1/100th that of YAG:Tb. Both CL and photoluminescence data show that the difference in the cathodoluminescence of YAG and NaY(WO{sub 4}){sub 2} can be understood in terms of differences in the mechanism of activation.
Due to their wide band gaps and high dielectric constants, the group III-nitrides have made significant impact on the compound semiconductor community as blue and ultraviolet light emitting diodes (LEDs) and for their potential use in laser structures and high temperature electronics. Processing of these materials, in particular wet and dry etching, has proven to be extremely difficult due to their inert chemical nature. We report electron cyclotron resonance (ECR) etch rates for GaN, InN, AlN, In{sub (x)}Ga{sub (1-x)}Ni and In{sub (x)}Al{sub (1-x)}N as a function of temperature, rf-power, pressure, and microwave power. Etch conditions are characterized for rate, profile, and sidewall and surface morphology. Atomic force microscopy (AFM) is used to quantify RMS roughness of the etched surfaces. We observe consistent trends for the InAlN films where the etch rates increase with increasing concentration of In. The trends are far less consistent for the InGaN with a general decrease in etch rate as the In concentration is increased.
Recent geologic and geophysical investigations within the Albuquerque Basin have shed light on the potentially seismogenic sources that might affect Sandia National Laboratories, New Mexico (SNL/NM), a multi-disciplinary research and engineering facility of the US Department of Energy (DOE). This paper presents a summary of potentially seismogenic sources for SNL/NM, emphasizing those sources within approximately 8 kilometers (km) of the site. Several significant faults of the central Rio Grande rift transect SNL/NM. Although progress has been made on understanding the geometry and interactions of these faults, little is known of the timing of most recent movement or on recurrent intervals for these faults. Therefore, whether particular faults or fault sections have been active during the Holocene or even the late Pleistocene is undocumented. Although the overall subdued surface expression of many of these faults suggests that they have low to moderate slip rates, the proximity of these faults to critical (e.g., nuclear) and non-critical (e.g., high-occupancy, multistory office/light lab) facilities at SNL/NM requires their careful examination for evaluation of potential seismic hazard.
Remote monitoring systems presently operating in facilities in a number of countries around the world are providing valuable information on the installation and operation of such systems. Results indicate they are performing reliably. While the technology for remote monitoring exists today, it may be some time before numerous constraints on implementation can be resolved. However, the constraints should not prevent the designing of systems that can be used for remote monitoring. Selection of the proper technology path for future development should include a flexible approach to front-end detection, data formats, data processing, and other areas. A brief description of two of the existing remote monitoring systems, and some general recommendations for future remote monitoring systems, will be presented.
A number of different disposition alternatives are being considered and include facilities which provide for long-ten-n and interim storage, convert and stabilize fissile materials for other disposition alternatives, immobilize fissile material in glass and/or ceramic material, fabricate fissile material into mixed oxide (MOX) fuel for reactors, use reactor based technologies to convert material into spent fuel, and dispose of fissile material using a number of geologic alternatives. Particular attention will be given to the reactor alternatives which include existing, partially completed, advanced or evolutionary LWRs and CANDU reactors. The various reactor alternatives are all very similar and include processing which converts Pu to a usable form for fuel fabrication, a MOX fuel fab facility located in either the US or in Europe, US LWRs or the CANDU reactors and ultimate disposal of spent fuel in a geologic repository. This paper focuses on how the objectives of reducing security risks and strengthening arms reduction and nonproliferation will be accomplished and the possible impacts of meeting these objectives on facility operations and design. Some of the areas in this paper include: (1) domestic and international safeguards requirements, (2) non-proliferation criteria and measures, (3) the threat, and (4) potential proliferation risks, the impacts on the facilities, and safeguards and security issues unique to the presence of Category 1 or strategic special nuclear material.
A system has been developed by Sandia National Laboratories (SNL) as part of the joint laboratory project with Los Alamos National Laboratory and Argonne National Laboratory-West (ANL-W). The objective is to provide support for Safeguards and Security and Nuclear Materials Control and Accountability within the DOE complex. Since its original design PAMTRAK has been enhanced to include material monitoring, personnel monitoring, and video surveillance. Material monitoring is provided by the WATCH (Wireless Alarm Transmission of Container Handling) subsystem by performing continuous surveillance via constantly monitored Tamper Indicating Devices of all material not directly involved in the fuel manufacturing process. Personnel tracking uses radio frequency and infrared sensors to detect unauthorized access to restricted areas and to enforce constant monitoring of containers or other objects within a ``region of interest`` in a storage vault or other restricted area. Advantages of combining these sensor subsystems include reducing personnel radiation exposure by extending the time between required physical inventory intervals as well as adding robustness to existing security measures. PAMTRAK is being demonstrated as part of the integrated materials monitoring and accounting system in the Fuels and Manufacturing Facility (FMF) located at ANL-W. This paper will describe the technologies employed for installation of the system by SNL, as well as the operational issues involved in using the system at ANL-W.
Long-term repository assessment must consider the processes of (1) gas generation, (2) room closure and expansions due to salt creep, and (3) multiphase (brine and gas) fluid flow, as well as the complex coupling between these three processes. The mechanical creep closure code SANCHO was used to simulate the closure of a single, perfectly sealed disposal room filled with water and backfill. SANCHO uses constitutive models to describe salt creep, waste consolidation, and backfill consolidation, Five different gas-generation rate histories were simulated, differentiated by a rate multiplier, f, which ranged from 0.0 (no gas generation) to 1.0 (expected gas generation under brine-dominated conditions). The results of the SANCHO f-series simulations provide a relationship between gas generation, room closure, and room pressure for a perfectly sealed room. Several methods for coupling this relationship with multiphase fluid flow into and out of a room were examined. Two of the methods are described.
Many studies employ multiple measurement instruments such as human raters, observers, judges, or mechanical gauges to record subject data. It is well known that the consistency of these instruments, commonly called rater reliability, limits the extent to which conclusions should be drawn from the observed data. However, the degree to which rater reliability limits conclusions has traditionally been assessed in only subjective manners. In this paper, a method is developed for objectively quantifying the impact of rate reliability on the statistical analysis of data from a commonly used collection scheme. This method allows the inclusion of a reliability index in statistical power calculations and is an invaluable tool in the planning of experiments.
The Laboratories Services Division of Sandia National Laboratories includes a wide variety of operations such as environmental, safety and health, safeguards and security, facilities, logistics, and sites planning and integration. In the face of declining budgets and increasing requirements, the Management Team needed some tools to assist in negotiating with customers and regulators and in consistently and cost-effectively managing all work performed and/or managed by the Division. The Integrated Services Management System (ISMS) was developed as a series of processes to provide these tools. The Laboratory Integration and Prioritization System (LIPS) was selected as the prioritization methodology for ISMS. The pilot application phase was begun in February 1994 and addressed planning of work and resources for FY95. Extensive training was provided for the Activity Data Sheet (ADS) preparers and the teams which would score each of the activities. After preparation of the ADSs, they were scored by the scoring teams. A division-wide review board reviewed all of the ADSs to ensure consistency of scoring across all of the functional areas. The lessons that were learned from the pilot application were evaluated and improvements incorporated for the FY96 planning and application. The improvements included upgrading the training, providing expert facilitation for scoring boards, modification of the scoring instructions to better represent local situations, and establishing an Validation Board with more authority and accountability to provide quality assurance. The participants in the LIPS process have agreed that no major bases were uncovered, imperfect prioritizations are better than no data, all work packages can be scored and ranked, including core activities, results were objective and quantifiable, and decisions could be made using technically defensible bases.
Customers of Asynchronous Transfer Mode (ATM) services may need a variety of data authenticity and privacy assurances. Cryptographic methods can be used to assure authenticity and privacy, but are hard to scale for implementation at high speed. The incorporation of these methods into computer networks can severely impact functionality, reliability, and performance. To study these trade-offs, a prototype encryptor/decryptor was developed. This effort demonstrated the viability of implementing certain encryption techniques in high speed networks. The research prototype processes ATM cells in a SONET OC-3 payload. This paper describes the functionality, reliability, security, and performance design trade-offs investigated with the prototype.
New developments in dry and wet etching, ohmic contacts and epitaxial growth of Ill-V nitrides are reported. These make possible devices such as microdisk laser structures and GaAs/AlGaAs heterojunction bipolar transistors with improved InN ohmic contacts.