Publications

The goal of the Stretched-Membrane Dish Program is the development of a dish solar concentrator fabricated with a single optical element capable of collecting 60 kWt. Solar Kinetics, Inc., has constructed a prototype 7-meter dish to demonstrate the manufacturability and optical performance of this innovative design. The reflective surface of the dish consists of a plastically deformed metal membrane with a separate reflective polymer membrane on top, both held in place by a low-level vacuum. Sandia conducted a test program to determine the on-sum performance of the dish. The vacuum setting was varied 8.9- to 17. 2-cm of water column and the vertex to target distance was varied over a range of 15.24 cm to evaluate beam quality. The optimal setting for the vacuum was 11.4 centimeters of water column with the best beam quality of 6.4 centimeters behind the theoretical focal point of the dish. Flux arrays based on slope error from the CIRCE2 computer code were compared to the measured flux array of the dish. The uniformly distributed slope error of 2.3 milliradians was determined as the value that would produce a modeled array with the minimum mean square difference to the measured array. Cold water calorimetry measured a power of 23.3 {plus minus} .3 kWt. Reflectivity change from an initial value of 88.3% to 76.7% over a one year period. 12 refs.

Pulsed high field magnet coils are an integral part of the applied-B ion diode used in the light ion Inertial Confinement Fusion program at Sandia National Laboratories. Several factors have contributed in recent years to the need for higher magnetic fields of these applied-B ion diodes. These increased magnetic field requirements have precipitated the development of better engineering tools and techniques for use in the design of applied-B ion diodes. This paper describes the status of the applied-B ion diode engineering at Sandia. The design process and considerations are discussed. A systematic approach for maximizing the field achievable from a particular coil system consisting of the capacitor bank, the feeds, and the coil is presented. A coupled electromechanical finite element analysis is also described.

Rock mechanisms parameters such as the in situ stresses, elastic properties, failure characteristics, and poro-elastic response are important to most completion and stimulation operations. Perforating, hydraulic fracturing, wellbore stability, and sand production are examples of technology that are largely controlled by the rock mechanics of the process. While much research has been performed in these areas, there has been insufficient application that research by industry. In addition, there are new research needs that must be addressed for technology advancement.

We describe the use of the object-oriented language C++ in the development of a hydrocode simulation system, PCTH. The system is designed to be horizontally and vertically portable from low-end workstations to next generation massively parallel supercomputers. The development of the PCTH system and the issues and rationale considered in moving to the object oriented paradigm will be discussed.

The goals and time constraints of developing the next generation shock code, RHALE++, for the Computational Dynamics and Adaptive Structures Department at Sandia National Laboratories have forced the development team to closely examine their program development environment. After a thorough investigation of possible programming languages, the development team has switched from a FORTRAN programming environment to C++. This decision is based on the flexibility, strong type checking, and object-oriented features of the C++ programming language. RHALE++ is a three dimensional, multi-material, arbitrary Lagrangian Eulerian hydrocode. Currently, RHALE++ is being developed for von Neumann, vector, and MIMD/SIMD computer architectures. Using the object oriented features of C++ facilitates development on these different computer architectures since architecture dependences such as inter processor communication, can be hidden in base classes. However, the object oriented features of the language can create significant losses in efficiency and memory utilization. Techniques, such as reference counting, have been developed to address efficiency problems that are inherent in the language. Presently, there has been very little efficiency loss realized on SUN scalar and nCUBE massively parallel computers; however, although some vectorization has been accomplished on CRAY systems, significant efficiency losses exist. This paper presents the current status of using C++ as the development language for RHALE++ and the efficiency that has been realized on SUN, CRAY, and nCUBE systems.

Depleted uranium (DU) is used in high level radioactive waste transport containers as a gamma shield. The mechanical response of this material has generally not been included in calculations intended to assure that these casks will maintain their containment function during all normal use and accident conditions. If DU could be qualified as a structural component, the thickness of other materials (e.g. stainless steel) in the primary containment boundary could be reduced, thereby allowing a reduction in cask mass and/or an increase in payload capacity. This study was conducted to determine the mechanical behavior of a range of DU alloys in order to extend the limited set of mechanical properties reported in the literature. These mechanical properties were used as the basis for finite element calculations to quantify the potential for claiming structural credit for DU.

Variations of bed void fraction in a full-scale, reacting, fixed-bed coal gasifier have been deduced from measured axial pressure profiles obtained during gasification of seven coal types ranging from lignite to bituminous. Packed-bed pressure correlations were used to calculate the void fractions based on monotonic polynomial fits of measured pressure profiles. Insights into the fixed-bed combustion processes affected by the void distribution were obtained by a one-dimensional, steady-state, fixed-bed combustion model. Predicted temperature profiles from this model compare reasonably well to experimental data. The bed void distributions are not linear but are perturbed by vigorous reactions in the devolatilization and oxidation zones. Results indicate that a dramatic increase in temperature and associated gas release causes the bed to expand and the gas void space to increase. Increased void space localized in the combustion zone causes the steep temperature gradient to decrease and the location of the maximum temperature to shift. Also, large feed gas flow rates cause the void fraction in the ash zone to increase.

Crosshole shear-wave seismic surveys have been used to monitor the distribution of injected air in the subsurface during an in situ air stripping waste remediation project at the Savannah River site in South Carolina. To remove the contaminant, in this case TCE`s from a leaking sewer line, two horizontal wells were drilled at depths of 20 m and 52 m. Air was pumped into the lower well and a vacuum was applied to the upper well to extract the injected air. As the air passed through the subsurface, TCE`s were dissolved into the gas and brought out the extraction well. Monitoring of the air injection by crosshole shear wave seismics is feasible due to the changes in soil saturation during injection resulting in a corresponding change in seismic velocities. Using a downhole shear-wave source and clamped downhole receiver, two sets of shear-wave data were taken. The first data were taken before the start of air injection, and the second taken during. The difference in travel times between the two data sets were tomographically inverted to obtain velocity differences. Velocity changes ranging up to 3% were mapped corresponding to saturation changes up to 24%. The distribution of these changes shows a desaturation around the position of the injection well with a plume extending in the direction of the extraction well. Layers with higher clay content show distinctively less change in saturation than the regions with higher sand content.

Numerical optimization has been successfully used to obtain optimal designs in a more efficient and structured manner in many industries. Optimization of sizing variables is already a widely used design tool and even though shape optimization is still an active research topic, significant successes have been achieved for many structural analysis problems. The transportation cask design problem seems to have the formulation and requirements to benefit from numerical optimization. Complex structural, thermal and radiation shielding analyses associated with cask design constraints can be integrated and automated through numerical optimization to help meet the growing needs for safe and reliable shipping containers. Improved overall package safety and efficiency with cost savings in the design and fabrication can also be realized. Sandia National Laboratories (SNL) has the opportunity to be a significant contributor in the development of new sophisticated transportation cask design tools. Current state-of-the-art technology at SNL in the areas of structural mechanics, thermal mechanics, numerical analysis, adaptive finite element analysis, automatic mesh generation, and transportation cask design can be combined to enhance current industry-standard cask design and analysis techniques through numerical optimization.

This report describes in details the operations necessary to perform a test on the Sandia National Laboratories 18-Inch Actuator. This report is to sever as a training aid for personnel learning to operate the Actuator. A complete description of the construction and operation of the Actuator is also given. The control system, data acquisition system, and high-pressure air supply system are also described. Detailed checklists, with an emphasis on safety, are presented for test operations and for maintenance.

The Hazardous Material Identification Process is a guide to pre-characterization of excess weapon hardware for environmental and safety hazards prior to introduction of the hardware into a waste stream. A procedure for planning predisposal processing of hardware for declassification, demilitarization, and separation/expenditure of certain hazards is included. Final characterization of the resultant waste streams is left to the cognizant waste management agency or organization.

The 2-D code MAGIC and TRAJ have been used for extensive studies of diode, IFR channel, and accelerating gap problems in the recirculating linear accelerator (RLA). Typical beam parameters use 10--20 kA, 3--4 MeV. This report summarizes recent results from these simulations. We have also designed possible injectors for the proposed BOLT experiment, with typical beams at 100 A, 1.0--1.5 MeV. Finally, we discuss some preliminary diode runs of proposed 100 MV, 500 kA accelerator using the SMILE/HERMES method of adding voltages from many cavities across a single immersed diode gap. 8 refs.

This report describes the progress of the three-dimensional mesh generation research, using plastering, during the 1990 fiscal year. Plastering is a 3-D extension of the two-dimensional paving technique. The objective is to fill an arbitrary volume with hexahedral elements. The plastering algorithm`s approach to the problem is to remove rows of elements from the exterior of the volume. Elements are removed, one level at a time, until the volume vanishes. Special closure algorithms may be necessary at the center. The report also discusses the common development environment and software management issues. 13 refs.

The AL-SX/2 and AL-SX/3 are recently certified Type B shipping containers for tritium reservoirs. Both containers consist of an outer stainless steel drum overpack and sealed stainless steel containment vessel. WR reservoirs provide containment of tritium for normal conditions of transport. In accident conditions the containment vessel of the AL-SX must contain the tritium. A variety of reservoirs and materials will be packaged inside the containment vessel. These materials must not produce high pressure gas products that exceed the internal pressure capability of the vessel if the container is in an accident involving fire. This report summarizes outgassing tests performed on various organic materials. Tests of commonly used materials show that increased pressure due to outgassing is not a problem at elevated temperatures that simulate an accident. This report summarizes outgassing tests performed on various materials that may be packaged inside the AL-SX during shipment. These materials (except the getter) are normally a part of the reservoir shipping configuration. The objective of the tests was to determine the temperature that these materials begin to generate high pressure gaseous products.

During June and July 1991, the Sandia Transportable Lightning Instrumentation Facility (SATTLIF) was fielded at the Department of Defense (DoD) Security Operations Test Site (SOTS) at Ft. McClellan, Alabama. Nine negative cloud-to-ground lightning flashes were artifically triggered to designated locations on Igloo 2, a weapons storage bunker specially prepared to allow instrumentation access to various of its structural and electrical system elements. Simultaneous measurements of the incident flash currents and responses at 24 test points within the igloo and its grounding counterpoise network were recorded under lightning attachments to the front and rear air terminals of the structure`s lightning protection system. In Volume I the test is described in detail. The measured data are summarized and discussed. Appendix A contains the full set of recorded incident flash currents, while Appendix B presents the set of largest responses measured at each test point, for both front and rear attachments to the structure. As part of these tests, 0.050-in-thick stainless steel, 0.08-in copper, and 0.08-in titanium samples were exposed to triggered flash currents. In this way, damage spots created by direct-strike triggered lightning have been obtained, along with the measurement of the return-stroke and continuing currents that produced them. These data points, along with similar ones on aluminum and ferrous steel obtained during 1990 will be used as benchmarks against which to quantify the fidelity of burnthrough testing achievable Sandia`s advanced laboratory lightning simulator.

A channel ions can focus and guide a relativistic electron beam. This report discuses the generation of plasma channels using magnetically confined low energy electron beams in a low pressure gas. The most significant advantages of these channels are that any gas can be ionized and that they can easily be made to follow a curved path. The major advantages are that the channel is less well confined than a laser produced channel and that a small solenoidal magnetic field is required. This report is intended to be a guide for those technicians and scientists who need to assemble and operate an e-beam generated plasma channel system. Hardware requirements are discussed in detail. There are brief discussions of operating techniques, channel diagnostic, and channel characteristics.

This report contains viewgraphs on topics in the following areas: plasma facing components (PFC) operation in devices; disruption studies; laboratory PFM and high heat flux research; R&D for future machines; and neutron effects on thermonuclear materials.

Data are presented from the 18 W/m{sup 2} Mockup for Defense High-Level Waste, a very large scale in situ test fielded underground at the Waste Isolation Pilot Plant (WIPP). These data include selected fielding information, test configuration, instrumentation activities, and comprehensive results from a large number of gages. The results in this report give measured data from the thermal response gages, i.e., thermocouples, flux meters, and heater power gages emplaced in the test. Construction of the test began in June 1984; gage data in this report cover the complete test duration, that is, to June 1990.

The objective of this project is to apply Sandia`s expertise and technology towards the development of stimulation diagnostic technology in the areas of in situ stress, natural fracturing, stimulation processes and instrumentation systems. Initial work has concentrated on experiment planning for a site where hydraulic fracturing could be evaluated and design models and fracture diagnostics could be validated and improved. Important issues have been defined and new diagnostics, such as inclinometers, identified. In the area of in situ stress, circumferential velocity analysis is proving to be a useful diagnostic for stress orientation. Natural fracture studies of the Frontier formation are progressing; two fracture sets have been found and their relation to tectonic events have been hypothesized. Analyses of stimulation data have been performed for several sites, primarily for in situ stress information. Some new ideas in stimulation diagnostics have been proposed; these ideas may significantly improve fracture diagnostic capabilities.

The Nuclear Waste Repository Technology Department at Sandia National Laboratories (SNL) is investigating the suitability of Yucca Mountain as a potential site for underground burial of nuclear wastes. One element of the investigations is to assess the potential long-term effects of groundwater flow on the integrity of a potential repository. A number of computer codes are being used to model groundwater flow through geologic media in which the potential repository would be located. These codes compute numerical solutions for problems that are usually analytically intractable. Consequently, independent confirmation of the correctness of the solution is often not possible. Code verification is a process that permits the determination of the numerical accuracy of codes by comparing the results of several numerical solutions for the same problem. The international nuclear waste research community uses benchmarking for intercomparisons that partially satisfy the Nuclear Regulatory Commission (NRC) definition of code verification. This report presents the results from the COVE-2A (Code Verification) project, which is a subset of the COVE project.

The Yucca Mountain Site Characterization Project is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level nuclear waste repository. Site characterization includes surface-based and underground testing. Analyses have been performed to design site characterization activities with minimal impact on the ability of the site to isolate waste, and on tests performed as part of the characterization process. One activity of site characterization is the construction of an Exploratory Studies Facility, which may include underground shafts, drifts, and ramps, and the accompanying ponds used for the storage of sewage water and muck water removed from construction operations. The information in this report pertains to the two-dimensional numerical calculations modelling the movement of sewage and settling pond water, and the potential effects of that water on repository performance and underground experiments. This document contains information that has been used in preparing Appendix I of the Exploratory Studies Facility Design Requirements document (ESF DR) for the Yucca Mountain Site Characterization Project.

The Yucca Mountain Site Characterization Project (YMP) is conducting studies to determine whether the Yucca Mountain site in southern Nevada will meet regulatory criteria for a potential mined geologic disposal system for high-level radioactive waste. Data gathered as part of these studies must be compiled and tabulated in a controlled manner for use in design and performance analyses. An integrated data management system has been developed to facilitate this process; this system relies on YMP participants to share in the development of the database and to ensure the integrity of the data. The site and Engineering Properties Database (SEPDB) is unique in that, unlike most databases where one data set is stored for use by one defined user, the SEPDB stores different sets of data which must be structured so that a variety of users can be given access to the information. All individuals responsible for activities supporting the license application should, to the extent possible,work with the same data and the same assumptions. For this reason, it is important that these data sets are readily accessible, comprehensive, and current. The SEPDB contains scientific and engineering data for use in performance assessment and design activities. These data sets currently consist of geologic, hydrologic, and rock properties information from drill holes and field measurements. The users of the SEPDB include engineers and scientists from several government research laboratories (Lawrence Livermore National Laboratory, Los Alamos National Laboratory, and Sandia National Laboratories), the US Geological Survey, and several government contractors. This manuscript describes the detailed requirements, contents, design, and status of the SEPDB, the procedures for submitting data to and/or requesting data from the SEPDB, and a SEPDB data dictionary (Appendix A) for defining the present contents.

Midway Valley, located at the eastern base of Yucca Mountain, Nye County, Nevada, has been identified as a possible location for the surface facilities of a potential high-level nuclear-waste repository. This structural and topographic valley is bounded by two north- trending, down-to-the-west normal faults: the Paintbrush Canyon fault on the east and the Bow Ridge fault on the west. Surface and near-surface geological data have been acquired from Midway Valley during the past three years with particular emphasis on evaluating the existence of Quaternary faults. A detailed (1:6000) surficial geological map has been prepared based on interpretation of new and existing aerial photographs, field mapping, soil pits, and trenches. No evidence was found that would indicate displacement of these surficial deposits along previously unrecognized faults. However, given the low rates of Quaternary faulting and the extensive areas that are covered by late Pleistocene to Holocene deposits south of Sever Wash, Quaternary faulting between known faults cannot be precluded based on surface evidence alone. Middle to late Pleistocene alluvial fan deposits (Unit Q3) exist at or near the surface throughout Midway Valley. Confidence is increased that the potential for surface fault rupture in Midway Valley can be assessed by excavations that expose the deposits and soils associated with Unit Q3 or older units (middle Pleistocene or earlier).

The US Department of Energy (DOE) has developed a site characterization plan (SCP) to collect detailed information on geology, geohydrology, geochemistry, geoengineering, hydrology, climate, and meteorology (collectively referred to as ``geologic information``) of the Yucca Mountain site. This information will be used to determine if a mined geologic disposal system (MGDS) capable of isolating high-level radioactive waste without adverse effects to public health and safety over 10,000 years, as required by regulations 40 CFR Part 191 and 10 CFR Part 60, could be constructed at the Yucca Mountain site. Forecasts of future climates conditions for the Yucca Mountain area will be based on both empirical and numerical techniques. The empirical modeling is based on the assumption that future climate change will follow past patterns. In this approach, paleclimate records will be analyzed to estimate the nature, timing, and probability of occurrence of certain climate states such as glacials and interglacials over the next 10,000 years. For a given state, key climate parameters such as precipitation and temperature will be assumed to be the same as determined from the paleoclimate data. The numerical approach, which is the primary focus of this paper, involves the numerical solution of basic equations associated with atmospheric motions. This paper describes these equations and the strategy for solving them to predict future climate conditions around Yucca Mountain.

The Strategic Defense Initiative Organization (SDIO) decided to investigate the possibility of launching a Russian Topaz 11 space nuclear power system. A preliminary safety assessment was conducted to determine whether or not a space mission could be conducted safely and within budget constraints. As part of this assessment, a safety policy and safety functional requirements were developed to guide both the safely assessment and future Topaz II activities. A review of the Russian flight safety program was conducted and documented. Our preliminary safety assessment included a top level event tree, neutronic analysis of normal and accident configurations, an evaluation of temperature coefficients of reactivity, a reentry and disposal analysis, and analysis of postulated launch abort impact accidents, and an analysis of postulated propellant fire and explosion accidents. Based on the assessment, it appears that it will be possible to safely launch the Topaz II system in the US with some possible system modifications. The principal system modifications will probably include design changes to preclude water flooded criticality and to assure intact reentry.