Distributed point-focusing solar concentrators are being developed for dish-Stirling systems and other applications. Many of these concentrators make use of faceted mirrors that have to be accurately aligned. Some of the solar concentrator designs use stretched-membrane facets that also require focusing. Accurate mirror alignment and focus of faceted solar concentrators have two benefits. First, the concentration ratio of the concentrator/receiver (collector) system is improved with accurate alignment and focus. The receiver aperture diameter can therefore be smaller, thereby reducing thermal losses from the receiver and improving the overall efficiency of the collector. Second, and perhaps more importantly, flux intensities on the receiver can be sensitive to facet alignment and focus. In this paper, the theory and practical application of an alignment and focusing technique are presented. In the technique, light from an artificial source is reflected from the concentrator`s facets to a target. From basic geometric principles, the shape and location of the reflected light on the target can be predicted. Alignment is accomplished by adjusting the facets aim so that the reflected image falls on the predetermined location. To focus a stretched-membrane facet, the reflected image size is adjusted to match that of the target. The governing equations used to draw the alignment targets are developed and the practical application of the technique to the alignment and focus of the Cummins Power Generation, Inc. CPG-460 are presented. Alignment uncertainty associated with this technique on the CPG-460 is also discussed.
This report gives a brief description of the development activities for the MC3994 and MC3994A relays, including their mechanical and electrical characteristics. The basic details of the design were presented in SAND85-1288, {open_quotes}Characteristics and Development Report for the MC3593 and MC3594 Relays.{close_quotes} This report also summarizes test results and describes the tests that were performed to ensure that the MC3994 and MC3994A had adequate design margin in accordance with the capability drawing requirements.
In this paper, we report on a project to develop a unified approach for building a library of collective communication operations that performs well on a cross-section of problems encountered in real applications. The target architecture is a two-dimensional mesh with worm-hole routing, but the techniques also apply to higher dimensional meshes and hypercubes. The approach differs from traditional library implementations in that we address the need for implementations that perform well for various sized vectors and grid dimensions, including non-power-of-two grids. We show how a general approach to hybrid algorithms yields performance across the entire range of vector lengths. Moreover, many scalable implementations of application libraries require collective communication within groups of nodes. Our approach yields the same kind of performance for group collective communication. Results from the Intel Paragon system are included.
This report revises the original report that was published in 1980. Some of the topics covered in the earlier report were provisional and it is now practicable to reexamine them using new or revised geotechnical data and that obtained from SPR cavern operations, which involves 16 new caverns. Revised structure maps and sections show interpretative differences as compared with the 1980 report and more definition in the dome shape and caprock structural contours, especially a major southeast-northwest trending anomalous zone. The original interpretation was of westward tilt of the dome, this revision shows a tilt to the southeast, consistent with other gravity and seismic data. This interpretation refines the evaluation of additional cavern space, by adding more salt buffer and allowing several more caverns. Additional storage space is constrained on this nearly full dome because of low-lying peripheral wetlands, but 60 MMBBL or more of additional volume could be gained in six or more new caverns. Subsidence values at Bryan Mound are among the lowest in the SPR system, averaging about 11 mm/yr (0.4 in/yr), but measurement and interpretation issues persist, as observed values are about the same as survey measurement accuracy. Periodic flooding is a continuing threat because of the coastal proximity and because peripheral portions of the site are at elevations less than 15 ft. This threat may increase slightly as future subsidence lowers the surface, but the amount is apt to be small. Caprock integrity may be affected by structural features, especially the faulting associated with anomalous zones. Injection wells have not been used extensively at Bryan Mound, but could be a practicable solution to future brine disposal needs. Environmental issues center on the areas of low elevation that are below 15 feet above mean sea level: the coastal proximity and lowland environment combined with the potential for flooding create conditions that require continuing surveillance.
Sandia National Laboratories, mission is to solve important problems in the areas of national defense, energy security, environmental integrity, and industrial technology. The Laboratories` strategy for accomplishing this mission is to conduct research to provide an understanding of the important physical phenomena underlying any problem, and then to construct validated computational models of the phenomena which can be used as tools to solve the problem. In the course of implementing this strategy, Sandia`s technical staff has produced a wide variety of numerical problem-solving tools which they use regularly in the design, analysis, performance prediction, and optimization of Sandia components, systems and manufacturing processes. This report provides the relevant technical and accessibility data on the numerical codes used at Sandia, including information on the technical competency or capability area that each code addresses, code ``ownership`` and release status, and references describing the physical models and numerical implementation.
The Department of Energy Order 5500.3A requires facility-specific hazards assessments be prepared, maintained, and used for emergency planning purposes. This hazards assessment document describes the chemical and radiological hazards associated with the Simulation Technology Laboratory, Building 970. The entire inventory was screened according to the potential airborne impact to onsite and offsite individuals. The air dispersion model, ALOHA, estimated pollutant concentrations downwind from the source of a release, taking into consideration the toxicological and physical characteristics of the release site, the atmospheric conditions, and the circumstances of the release. The greatest distances at which a postulated facility event will produce consequences exceeding the ERPG-2 and Early Severe Health Effects thresholds are 78 and 46 meters, respectively. The highest emergency classification is a Site Area Emergency. The Emergency Planning Zone is 100 meters.
The purpose of this report is to assess the availability of technologies to seal underground openings. The technologies are needed to seal the potential high-level radioactive waste repository at Yucca Mountain. Technologies are evaluated for three basic categories of seal components: backfill (general fill and graded fill), bulkheads, and grout curtains. Not only is placement of seal components assessed, but also preconditioning of the placement area and seal component durability. The approach taken was: First, review selected sealing case histories (literature searches and site visits) from the mining, civil, and defense industries; second, determine whether reasonably available technologies to seal the potential repository exist; and finally, identify deficiencies in existing technologies. It is concluded that reasonably available technologies do exist to place backfill, bulkheads, and grout curtains. Technologies also exist to precondition areas where seal components are to be placed. However, if final performance requirements are stringent for these engineered structures, some existing technologies may need to be developed. Deficiencies currently do exist in technologies that demonstrate the long-term durability and performance of seal components. Case histories do not currently exist that demonstrate the placement of seal components in greatly elevated thermal and high-radiation environments and in areas where ground support (rock bolts and concrete liners) has been removed. The as-placed, in situ material properties for sealing materials appropriate to Yucca Mountain are not available.
A comprehensive laboratory investigation is determining the mechanical properties of tuffs for the Yucca Mountain Site Characterization Project (YMP). Most recently, experiments have been performed on tuff samples from a series of drill holes along the planned alignment of the Exploratory Study Facilities (ESF) north ramp. Unconfined compression and indirect tension experiments were performed and the results are being analyzed with the help of bulk property information. The results on samples from eight of the drill holes are presented. In general, the properties vary widely, but are highly dependent on the sample porosity. The developed relationships between mechanical properties and porosity are powerful tools in the effort to model the rock mass response of Yucca Mountain to the emplacement of the potential high-level radioactive waste repository.
Experimental results are presented for bulk and mechanical properties measurements on specimens of the Paintbrush tuff recovered from borehole USW NRG-6 at Yucca Mountain, Nevada. Measurements have been performed on four thermal/mechanical units, TCw, PTn, TSw1 and TSw2. On each specimen the following bulk properties have been reported: dry bulk density, saturated bulk density, average grain density, and porosity. Unconfined compression to failure, confined compression to failure, and indirect tensile strength tests were performed on selected specimens recovered from the borehole. In addition, compressional and shear wave velocities were measured on specimens designated for unconfined compression and confined compression experiments. Measurements were conducted at room temperature on nominally water saturated specimens; however, some specimens of PTn were tested in a room dry condition. The nominal strain rate for the fracture experiments was 10{sup -5} s {sup -1}.
The mismatch control technique that is used to simplify model equations of motion in order to determine analytic optimal control laws is extended using neighboring extremal theory. The first variation optimal control equations are linearized about the extremal path to account for perturbations in the initial state and the final constraint manifold. A numerical example demonstrates that the tuning procedure inherent in the mismatch control method increases the performance of the controls to the level of a numerically-determined piecewise-linear controller.
The Department of Energy (DOE) is required to prepare and submit Site Treatment Plans (STPS) pursuant to the Federal Facility Compliance Act (FFCAct). Although the FFCAct does not require that disposal be addressed in the STPS, the DOE and the States recognize that treatment of mixed low-level waste will result in residues that will require disposal in either low-level waste or mixed low-level waste disposal facilities. As a result, the DOE is working with the States to define and develop a process for evaluating disposal-site suitability in concert with the FFCAct and development of the STPS. Forty-nine potential disposal sites were screened; preliminary screening criteria reduced the number of sites for consideration to twenty-six. The DOE then prepared fact sheets for the remaining sites. These fact sheets provided additional site-specific information for understanding the strengths and weaknesses of the twenty-six sites as potential disposal sites. The information also provided the basis for discussion among affected States and the DOE in recommending sites for more detailed evaluation.
Cores containing natural fractures were obtained from drillholes UE 25 NRG-4 and USW NRG-6 at Yucca Mountain, Nevada. Seven selected fractures were sheared at constant normal stress, either 5 or 10 MPa, in the air-dry condition. Detailed profilometer data were collected from each fracture surface before testing. The tests yielded the normal closure as a function of normal stress, and the shear stress and dilation as a function of shear offset. The constitutive properties resulting from the measurements were: normal stiffness, shear stiffness, shear strength and coefficient of friction, and dilation. Peak friction ranged from 0.89 to 1.11; residual friction ranged from 0.76 to 1.00. The lowest initial dilation angle was found to be 5.29{degrees} and the highest was 11.28{degrees}. The roughness characteristics of the fracture surfaces agree qualitatively with the simple mathematical model of Brown (1994) derived from fracture data in many other rock types.
The Yucca Mountain Site Characterization Project has been assigned the task of determining the suitability of the Yucca Mountain site. Among the concerns being investigated, the characterization of the mechanical properties of the fractures present in the host rock had direct relevance to repository design, and the pre- and post-closure performance assessment. Cores from drillholes NRG-4 and NRG-6 containing natural fractures were obtained from the Sample Management Facility at Yucca Mountain, Nevada. Seven selected fracture were sheared at constant normal stress, either 5 or 10 MPa, in the as-received condition (air-dry). Detailed profilometer data was collected from each fracture surface before testing. The tests yielded the normal closure as a function of normal stress, and the shear stress and dilation as a function of shear offset. The constitutive properties resulting from the measurements were: normal stiffness, shear stiffness, shear strength and coefficient of friction, and dilation. Peak friction ranged from 0.89 to 1.11; residual friction ranged from 0.76 to 1.00. The lowest initial dilation angel was found to be 5.29{degree} and the highest was 11.28{degree}. The roughness characteristics of the fracture surfaces agree qualitatively with the simple mathematical model of Brown (1984) derived from fracture data in many other rock types.
Design alternatives for the International Atomic Energy Agency`s Spent Fuel Attribute Tester (SFAT) were evaluated using radiation transport calculations. Several design changes were recommended and implemented in a new SFAT device. The new SFAT was tested on September 8 and 9, 1993, at the Industrial Power Company, Ltd. intermediate spent fuel storage facility in Olkiluoto, Finland. The new SFAT performed very well. The results of the tests are compared with predictions made during the SFAT optimization study.
On August 4, 1994, a Pollution Prevention Opportunity Assessment (PPOA) for the Print Shop was initiated by Print Shop Manager Bruce Fetzer and the Pollution Reduction Group (PRG).
The fatigue analysis of a wind turbine component typically uses representative samples of cyclic loads to determine lifetime loads. In this paper, several techniques currently in use are compared to one another based on fatigue life analyses. The generalized Weibull fitting technique is used to remove the artificial truncation of large-amplitude cycles that is inherent in relatively short data sets. Using data from the Sandia/DOE 34-m Test Bed, the generalized Weibull file technique is shown to be excellent for matching the body of the distribution of cyclic loads and for extrapolating the tail of the distribution However, the data also illustrate that the fitting technique is not a substitute for an adequate data base.
This report summarizes the environmental surveillance activities conducted by Sandia National Laboratories, the US Environmental Protection Agency, and Reynolds Electrical and Engineering Company for the Tonopah Test Range operated by Sandia National Laboratories. Sandia National Laboratories` responsibility for environmental monitoring results extend to those activities performed by Sandia National Laboratories or under its direction. Results from other environmental monitoring activities are included to provide a measure of completeness in reporting. Other environmental compliance programs such as the National Environmental Policy Act of 1969, environmental permits, and environmental restoration and waste management programs are also included in this report, prepared for the US Department of Energy in compliance with DOE Order 5400.1.
The MELCOR computer code has been used to model four of the large-scale aerosol behavior experiments conducted in the Containment System Test Facility (CSTF) vessel. Tests AB5, AB6 and AB7 of the ABCOVE program simulate the dry aerosol conditions during a hypothetical severe accident in an LMFBR. Test LA2 of the LACE program simulates aerosol behavior in a condensing steam environment during a postulated severe accident in an LWR with failure to isolate the containment. The comparison of code results to experimental data show that MELCOR is able to correctly predict most of the thermal-hydraulic results in the four tests. MELCOR predicts reasonably well the dry aerosol behavior of the ABCOVE tests, but significant disagreements are found in the aerosol behavior modelling for the LA2 experiment. These results tend to support some of the concerns about the MELCOR modelling of steam condensation onto aerosols expressed in previous works. During these analyses, a limitation in the MELCOR input was detected for the specification of the aerosol parameters for more than one component. A Latin Hypercube Sampling (LHS) sensitivity study of the aerosol dynamic constants is presented for test AB6. The study shows the importance of the aerosol shape factors in the aerosol deposition behavior, and reveals that MELCOR input/output processing is highly labor intensive for uncertainty and sensitivity analyses based on LHS.