The purpose of this report is to provide general approaches and concepts that can be applied in validation of models used in performance assessment of high-level waste (HLW) repositories. The approaches are based on a validation strategy that Sandia National Laboratories has implemented as participants in the International Transport Validation Study (INTRAVAL). This strategy focuses on the demonstration that performance assessment models are adequate representations of the real systems they are intended to represent, given the pertinent regulatory requirements rather than proving absolute correctness from the purely scientific point of view. Positions that are taken consist of the following: due to the relevant time and space scales, models that are used to assess the performance of a HLW repository can never be validated; therefore, validation is a process that consists of building confidence in these models and not providing "validated" models; in this context, model validation includes comparisons to "reality," however, adequacy for the given purpose is the overall goal; comparisons to "reality" consist of comparing model predictions against laboratory and field experiments, natural analogues, and site-specific information; when comparing experimental data to model predictions, a model can be either "invalid" or "not invalid," based on the null hypothesis concept, however, confidence in the model arises in finding a model to be "not invalid" over a wide range of conditions; an attempt should be made to consider in the validation process all plausible conceptual models; and when comparing experimental data to model predictions, a logical systematic approach should be followed. This report discusses the definition of validation in the context of performance assessment for HLW repositories, the need for validation, an approach to validation, and an approach to comparing model predictions with experimental data proposed by the authors.
During 1990, the Sandia Transportable Triggered Lightning Instrumentation Facility (SATTLIF) was designed, fabricated, and fielded at the Kentucky Space Center (KSC) rocket-triggered lighting test range in Florida. In preparation for lighting tests of a specially fitted munitions storage bunker during 1991, instrumentation for directly measuring lightning channel currents and response currents in structures was evaluated and demonstrated to function well. A set of 77-mil-thick 2024-T3 aluminum and 35-mil-thick 4130 steel metallic samples was exposed to measured triggered lighting flash currents. The resultant damage spots on these specimens represent the first such data points produced by known lighting currents. They are intended for use as benchmarks against which to improve and quantify the fidelity of laboratory simulations of lightning penetration. Two particularly significant results were obtained. In the first, a damage spot of approximately 0.3-inch diameter and >0.01-inch depth was produced by a continuing current of well less than median-level severity that transferred less than 13.6 coulombs of charge. In the second case, one of the steel samples was virtually burned through under a return-stroke/continuing current combination transferring an eightieth percentile charge of approximately 49 coulombs. Photographic evidence of upward-going streamers preceding return strokes initiated by dart leaders was also obtained and is presented. 17 refs., 34 figs., 4 tabs.
In September 1990, the President's Office of Science and Technology released a document that bears on the future of our nation's technological vigor and economic performance. Entitled, US Technology Policy, it is a statement of a set of broad principles that will constitute the federal government's technology policy for the 1990s. One of the leading principles of this policy is the imperative for cooperation and teamwork among government, industry, and academia, including an active, partnership role for the national laboratories in the mainstream US technology community. Until now, the nation's technology policy has never been explicit, although a tacit technology policy of one sort or another has at all times been in effect. The federal government has consistently been willing to create and fund institutions and programs to promote important national technology goals. Historical examples of such sponsorship include atomic energy, agriculture, aeronautics and space, energy, and medicine. The recognition in US Technology Policy that government has an active role to play in fostering technology development is a particularly significant admission. The vision of a partnership between the federal government and the private sector, as the policy outlines, provides a foundation upon which the national laboratories of the Department of Energy (DOE) can build to play a stronger role in enhancing US economic competitiveness. 6 refs.
A number of metal oxides were evaluated for their ability to immobilize molten LiCl-KCl eutectic in electrolyte-binder (EB) mixes used in thermally activated batteries. These metal oxides included fumed silicas, alumina, and a titania (all prepared by steam hydrolysis of the halides), floated silicas, MgO, and an alumina molecular sieve. The characteristics of the EB powders that were used as metrics were flow properties, homogeneity, BET surface area, particle-size distribution, and moisture content. The characteristics of EB pellets used as metrics were deformation at 530{degrees}C under an applied pressure and tendency for electrolyte leakage at 400{degrees}C. Many of the same characterization techniques used for EB powders were applied to the LiCl-KCl eutectic, its component halides, and the metal oxides as well. The reproducibility of the properties of several of the standard Sandia EB mixes was evaluated for materials prepared at a number of thermal-battery manufacturing facilities following the same processing procedures. 13 refs., 14 figs., 18 tabs.
An investigation of the impact of thermal aging on the flammability of two common types of nuclear grade electrical cables has been performed. Four large-scale flammability tests were performed with each of the two cable types tested in both an unaged (i.e., new off the reel) and a thermally aged (artificially aged) condition. In all cases, the fire was observed to consume virtually all of the combustible cable jacket and insulation material present. However, for both cable types tested, the thermal aging process caused a decrease in the cable flammability as demonstrated by decreases in the rate of fire growth, peak fire intensity, total heat released and near fire temperatures. This result is consistent with past cable aging studies because it has been observed that the thermal aging process will drive off certain of the more volatile constituents of a polymeric material. Presumably, when these aged materials are subjected to a fire, the evolution of volatile combustible gases is reduced as compared to the unaged materials, and hence, flammability is reduced. The results of these tests indicate that, at least for the two cable types tested, the evaluation of cable flammability using unaged cable samples will remain a conservative indicator of cable flammability in a thermally aged condition.
This investigation involves the development of a general two- dimensional continuum model to describe jointed rock mass. Chen recently developed a model for the analysis of rock mass containing two orthogonal joint sets. Development of the orthogonal joint set model followed the general formulation of Morland and the special single joint set implementation of Morland`s model by Thomas. Although the orthogonal joint set model has proven useful for analyzing field-scale problems, it remains restrictive in terms of the general field conditions. In this paper, the orthogonal joint set model has been extended to a more general model where the orthogonality restriction has been relaxed. Fundamental approaches remain the same for both models. However, as the general model becomes capable of treating physically more complicated problems, it becomes mathematically more complex. This complexity provides the potential to study more completely the interaction of various parameters representing the characteristics of jointed rock mass behavior. The equation governing the solution of the problem has been given, and example problems have been solved. The behavior of the rock mass predicted by the orthogonal joint set model has been compared to the general model. This model has been developed to aid in characterizing the site of the repository at Yucca Mountain, Nevada, for the potential geologic disposal of radioactive waste. Disposal of high-level nuclear waste is currently being considered by the Yucca Mountain Project, administered by the Nevada Operations Office of the US Department of Energy.
The distribution of moisture beneath a two-dimensional strip source is analyzed by applying the quasi-linear approximation. The source is described by specifying either the moisture content or the infiltration rate. A water table is specified at some depth, D, below the surface, the depth varying from shallow to semi-infinite. Numerical solutions are determined, via the boundary integral equation method, as a function of material sorptivity, {alpha}, the width of the strip source, 2L, and the depth to the water table. The moisture introduced at the source is broadly spread below the surface when {alpha}L {much_lt} 1, for which absorption by capillary forces is dominant over gravity-induced flow. Conversely, the distribution becomes finger-like along the vertical when {alpha}L {much_gt} 1, where gravity is dominant over absorption. For a source described by specifying the moisture content, the presence of a water table at finite depth influences the infiltration through the source when {alpha}D is less than about 4; infiltration rates obtained when the water table depth is semi-infinite are of sufficient accuracy for greater values of {alpha}D. When the source is described by a specified infiltration flux, the maximum allowable value of this flux for which the material beneath the source remains unsaturated is determined as a function of nondimensional sorptivity and depth to the water table. 30 refs., 16 figs., 2 tabs.
This report presents a summary of the conduct and findings of the Exploratory Shaft Alternatives Study. The study basis and findings are presented in sufficient detail to allow the Department of Energy to make an informed decision as to the Exploratory Shaft Facility (ESP)/Repository design option to be used as the basis for resumption of ESF Title 2 design. As a result of the desire for a rigorous, logically defensible analysis and the complexity of the required evaluation, a multi-attribute utility analysis was used as the primary decision-aiding tool. Over 2500 regulations, requirements and concerns were considered under four broad objectives. The analysis resulted in the ranking of 34 options, in accordance with the extent to which each option could achieve the objectives. Additional findings regarding design features that were identified as key elements in an options ability to provide good overall performance are also discussed. 4 figs., 9 tabs.
The objective of this work was to investigate whether a subsurface plume may be detected and followed using crosshole and surface-to-borehole electromagnetic geophysical techniques. both of these techniques were experimentally demonstrated to be feasible. The presence of the injected plume was easily detected with these methods but additional work must be done to refine the techniques. 5 refs., 15 figs., 1 tab.
The USDOE initiated the Production Risk Evaluation Program (PREP) at Sandia National Laboratories (SNL) to assess quantitatively the potential for serious production disruption as the result of random failures, accidents, natural disasters, or sabotage at its facilities. SNL developed a procedure incorporating both network and fault tree models that identifies production vulnerabilities. For each production step, a steady-state flow model computers the "critical time,'' which is the maximum period a step can be shut down without preventing the system from achieving production goals. The critical time is then used in fault tree analysis to determine the failure modes that can stop the process for longer than this period. Modular logic modeling is used for constructing the fault trees. Equipment restorable within its critical time need not be considered critical even though it may perform significant work. This paper focuses on sabotage, but the methodology is applicable to analyzing the other production system vulnerabilities mentioned above. The PREP models can be used to identify those plant areas to which a saboteur would need to gain access. A security strategy using graded protection based on a PREP analysis potentially could reduce security costs. PREP methods also provide quantitative insights to develop protection measures that do not infringe upon the liberties of personnel or complicate work practices.
Environmentally Conscious Manufacturing (ECM) refers to those processes that reduce the harmful environmental impacts of manufacturing, including minimization of hazardous waste, reduction of energy consumption, improvement of materials utilization efficiency, and improvement of operational safety. Approaches involve substitution of non-hazardous for hazardous materials, replacement of existing processes with new, waste-free processes, and increased use of recycle. Reducing waste at the source, through ECM, saves energy and money -- and provides value-added for the production and process. End-of-the-pipe treatment is much more expensive than waste minimization and ECM. Protecting the environment by reducing or eliminating waste is industrially efficient. Industry must create cleaner processes and products that contribute to profitability, rather than just focusing on pollution control. By expanding the return-on-investment equation, it can be shown that manufacturing products without producing hazardous wastes will result in an increase in industrial competitiveness. The optimum time to consider waste minimization is when a manufacturing process is first conceived. A significant and economically beneficial goal would be the development of zero effluent or closed loop manufacturing processes. Several programs at Sandia National Laboratories (SNL) are addressing the issues of waste minimization and pollution prevention through the application of ECM. Many of these programs involve collaboration with other national laboratories, industry, universities, and the production agencies. The following sections will provide a synopsis of Sandia's activities in ECM. 14 refs.
Polyurethane foams are dispensed into firesets to protect their electrical integrity under extreme environmental conditions. Although the production process has generally high precision, reliability problems have been identified. Preliminary results from a research program involving the use of rapid infrared sensors combined with multivariate analysis to monitor the blend of raw materials in near real time are presented. Two distinct regions of the infrared spectrum are considered. The mid infrared region is shown to make sufficiently precise concentration predictions while the near infrared region will require more experimentation. Both infrared regions will be considered for pilot and/or plant scale studies in order to completely specify the infrared sensor. The concentration predictions from the infrared sensor will be used in a closed loop control system in order to improve the reliability of the process.
The gas-generation characteristics of contact-handled transuranic waste from Rocky Flats Plant (RFP) and Idaho National Engineering Laboratory (INEL) will be tested at the Waste Isolation Pilot Plant (WIPP) in a series of bin-scale experiments. Bin-scale experiments are necessary because the extreme heterogeneity of CH TRU waste precludes adequate simulation of the waste in the laboratory. A stratified random sample of waste drums will be selected from the collection of drums at RFP and INEL that can be certified for shipment to the WIPP by August 1991. Before the waste is emplaced in the bins, 11 physical characteristics expected to control gas- generation behavior will be measured. These 11 controlling variables'' are expected to apply to all existing and future transuranic waste throughout the Department of Energy complex. Experiments will examine gas generation by radiolysis, microbial degradation, corrosion, and any synergistic mechanisms under many of the environmental conditions that will or may occur in the WIPP repository during the next 10,000 years. Because gas-generation behavior will be interpreted in terms of the controlling variables, gas generation by existing RFP/INEL waste that is not currently shippable, existing waste at other sites, and future waste can be predicted from the results of the WIPP bin-scale experiments. The results of the bin-scale experiments will support the WIPP Project's evaluation of compliance with 40 CFR 191, 40 CFR 268, and the National Environmental Policy Act. 55 refs., 13 figs., 18 tabs.
A series of impact experiments on polymethyl methacrylate (PMMA) manufactured by Polycast Technology Corporation has recently been completed using a light gas gun. The intent of this work was to compare these Hugoniot data with those data from a previous study on PMMA manufactured by Rohm and Haas. The results show that there are no significant differences in Hugoniot parameters for the two materials in the pressure range of 1.9 to 6.9 GPa. 8 refs., 10 figs., 3 tabs.
This report describes the current status and recent progress in the Advanced Handling Technology Project (AHTP) initiated to explore the use of advanced robotic systems and handling technologies to perform automated cask handling operations at radioactive waste handling facilities, and to provide guidance to cask designers on the impact of robotic handling on cask design. Current AHTP tasks have developed system mock-ups to investigate robotic manipulation of impact limiters and cask tiedowns. In addition, cask uprighting and transport, using computer control of a bridge crane and robot, were performed to demonstrate the high speed cask transport operation possible under computer control. All of the current AHTP tasks involving manipulation of impact limiters and tiedowns require robotic operations using a torque wrench. To perform these operations, a pneumatic torque wrench and control system were integrated into the tool suite and control architecture of the gantry robot. The use of captured fasteners is briefly discussed as an area where alternative cask design preferences have resulted from the influence of guidance for robotic handling vs traditional operations experience. Specific robotic handling experiences with these system mock-ups highlight a number of continually recurring design principles: (1) robotic handling feasibility is improved by mechanical designs which emphasize operation with limited dexterity in constrained workspaces; (2) clearances, tolerances, and chamfers must allow for operations under actual conditions with consideration for misalignment and imprecise fixturing; (3) successful robotic handling is enhanced by including design detail in representations for model-based control; (4) robotic handling and overall quality assurance are improved by designs which eliminate the use of loose, disassembled parts. 8 refs., 15 figs.
A dynamic finite element analysis was performed to study the penetration mechanics of a commercial fastener called Metal-Tack{reg sign}. This study evaluated the fastener and identified parametric changes required for attachment to AISI 1070 steel (R{sub c} = 26), a material harder than the fastener was designed for. A set of baseline calculations was performed to evaluate the fastener's performance in yellow brass, a much softer material. The analysis indicated that a driving energy of 3.03 ft{center dot}lbs was required to drive the tack into yellow brass. Excellent correlation of this model with experimental data provided confidence for applying the model to AISI 1070 steel. Tack performance was investigated with respect to variations in driving energy and tack strength. The results demonstrated that increasing driving energy was not sufficient for a successful attachment in the steel. An increase in tack strength was also required. Higher tack strength was obtained by increasing the heat treat specification of the tack material, Carpenter R.D.S. steel, to obtain a hardness of R{sub c} = 60. With this increase in strength and a driving energy of 20.8 ft{center dot}lb, the results indicated that the tack would attach but develop high plastic strain (21.5%) during attachment. The calculations were confirmed with tests using a high energy pyrotechnic driver developed to attach the tack. Finally, a geometry modification intended to reduce stress concentrations in the tack was evaluated experimentally but not computationally. The experimental results indicated an improvement in the tack strength and attachment quality. 4 refs., 19 figs., 4 tabs.
This report describes an automatic calibration system used in the calibration of all precision AC calibrators. The system includes an AC-DC Transfer Standard, a DC Voltage Standard, and a high-resolution digital multimeter, with an IBM-XT Personal Computer for data acquisition and analysis. Specialized instrumentation and measurement techniques make it possible to achieve high accuracy measurements with repeatability. 5 refs., 3 figs.
The Formerly Utilized Sites Remedial Action Program has updated an extensive objective concentration factor and biological half-life data base from the international marine radioecological literature. A microcomputer-based data management system has been implemented to provide statistical and graphic summaries of these data. The data base is constructed in a manner which allows subsets to be sorted using a number of interstudy variables such as organism category, tissue/organ category, geographic location (for in situ studies), and several laboratory-related conditions (e.g., exposure time and exposure concentrator). This report updates earlier reviews, and provides summaries of the tabulated data. In addition to the concentration factor/biological half-life data base, we provide an outline of other published marine radioecological works. Our goal is to present these data in a form that enables those concerned with predictive assessment of radiation dose in the marine environment to make a more judicious selection of data for a given application. 588 refs., 18 figs., 3 tabs.
The Pre-Tiger Team Self-Assessment (PTTSA) Report identified findings with respect to the way Sandia National Laboratories (SNL), Albuquerque, (including Tonopah Test Range (TTR) and Kauai Test Facility (KTF)) conducts its environment, safety, and health (ES H) activities. It presented Action Plan Requirements (APR) addressing these findings. The purpose of this PTTSA Action Plan Report is to assist in managing these action plan requirements by collecting, prioritizing, and estimating required resources. The specific objectives addressed by this report include: collection of requirements for the resolution of the findings presented in the PTTSA Report; consolidation of proposed Action Plan Requirements into logical Action Plan groupings for efficiency of resolution; categorization of Action Plans according to severity of the hazards represented by the findings; provision of a basis for long-range planning and issues management; documentation of the status of the proposed corrective actions; establishment of traceability of the corrective action to the original problem or issue; and integration of these plans into the existing ES H structure. The Action Plans in this report are an intermediate step between the identification of a problem or a finding in the PTTSA Report and the execution of the solution. They consist of requirements for solution, proposed actions, and an estimate of the time and (where applicable) resources required to develop the solution. This report is an input to the process of planning, resource commitment, development, testing, implementation, and maintenance of problem resolution. 2 figs.
This handbook outlines the basic job of guest editors for the HEART Conference proceedings, published by the DoD Nuclear Information and Analysis Center in the Journal of Radiation Effects, Research and Engineering. Suggestions are offered for procedures to aid the editors, authors, reviewers, and the publisher in assuring that the journal communicates clearly, concisely, and honestly.
The output intensity of a laser can be expressed in the form I{sub out} = Ag{sub 0}I{sub s} + BI{sub s}. The constants A and B are independent of the pump rate for laser systems with nonsaturable losses, but both g{sub 0}I{sub s} and I{sub s} can depend upon the pump rate. Methods for determining the pump rate dependence of g{sub 0}I{sub s} and I{sub s} are given for experiments in which the pump rate varies continuously. 6 refs., 1 fig.
A towed linear hydrophone array is subject to snakelike bending. If the array were processed as if it were truly linear, poor array gain coupled with a degraded source bearing estimate would result. The signal phase errors produced by sensor position uncertainty in passive sonar arrays are similar to those observed in Synthetic Aperture Radar (SAR) imagery. The Phase Gradient Autofocus (PGA) Algorithm has been shown to be a robust and effective method used to extract degrading phase errors prevalent in SAR imagery. This report shows that with slight modifications, the PGA algorithm can be applied to correct phase errors resulting from sensor position uncertainty introduced into linear-passive arrays. The results of the technique applied to simulated linear array data is also presented. 9 refs., 8 figs.
This document describes the NEFTRAN II (NEtwork Flow and TRANsport in Time-Dependent Velocity Fields) computer code and is intended to provide the reader with sufficient information to use the code. NEFTRAN II was developed as part of a performance assessment methodology for storage of high-level nuclear waste in unsaturated, welded tuff. NEFTRAN II is a successor to the NEFTRAN and NWFT/DVM computer codes and contains several new capabilities. These capabilities include: (1) the ability to input pore velocities directly to the transport model and bypass the network fluid flow model, (2) the ability to transport radionuclides in time-dependent velocity fields, (3) the ability to account for the effect of time-dependent saturation changes on the retardation factor, and (4) the ability to account for time-dependent flow rates through the source regime. In addition to these changes, the input to NEFTRAN II has been modified to be more convenient for the user. This document is divided into four main sections consisting of (1) a description of all the models contained in the code, (2) a description of the program and subprograms in the code, (3) a data input guide and (4) verification and sample problems. Although NEFTRAN II is the fourth generation code, this document is a complete description of the code and reference to past user`s manuals should not be necessary. 19 refs., 33 figs., 25 tabs.
The spatial correlation structure of volcanic tuffs at and near the site of the proposed high-level nuclear waste repository at Yucca Mountain, Nevada, is estimated using samples obtained from surface outcrops and drill holes. Data are examined for four rock properties: porosity, air permeability, saturated hydraulic conductivity, and dry bulk density. Spatial continuity patterns are identified in both lateral and vertical (stratigraphic) dimensions. The data are examined for the Calico Hills tuff stratigraphic unit and also without regard for stratigraphy. Variogram models fitted to the sample data from the tuffs of Calico Hills indicate that porosity is correlated laterally over distances of up to 3000 feet. If air permeability and saturated conductivity values are viewed as semi-interchangeable for purposes of identifying spatial structure, the data suggest a maximum range of correlation of 300 to 500 feet without any obvious horizontal to vertical anisotropy. Continuity exists over vertical distances of roughly 200 feet. Similar variogram models fitted to sample data taken from vertical drill holes without regard for stratigraphy suggest that correlation exists over distances of 500 to 800 feet for each rock property examined. Spatial correlation of rock properties violates the sample-independence assumptions of classical statistics to a degree not usually acknowledged. In effect, the existence of spatial structure reduces the ``equivalent`` number of samples below the number of physical samples. This reduction in the effective sampling density has important implications for site characterization for the Yucca Mountain Project.
The US Department of Energy (DOE) is responsible for designing, obtaining a license for, and constructing a geologic repository for the disposal of commercial high-level radioactive waste. The candidate repository site is currently at Yucca Mountain in Nevada. Part of DOE`s responsibility is to assess compliance with the appropriate environmental regulations, including the Environmental Protection Agency`s containment requirements in 40 CFR Part 191. Sandia National Laboratories (SNL) and Pacific Northwest Laboratories (PNL) have been contracted to aid DOE in the assessment of total systems performance. SNL has been tasked with evaluating and comparing the performance assessment methodologies developed by PNL and SNL, as applied to one conceptual model. In this report, SNL has attempted to reproduce, by way of a benchmark exercise, the results of PNL`s preliminary risk assessment of the proposed repository at Yucca Mountain. In general, the results of the PNL analysis and the SNL benchmark of that analysis agreed quite well, in terms of both ground-water flow and transport of unretarded radionuclides. The largest discrepancy between the analyses was noted for transport of retarded radionuclides, and was the result of different techniques for calculating retardation factors. 27 refs., 28 figs., 17 tabs.
The objective of this work is to develop a general method for remotely sensing the presence of tunneling activities using one or more boreholes and a combination of surface sources. New techniques for tunnel detection and location of tunnels containing no metal and of tunnels containing only a small diameter wire have been experimentally demonstrated. A downhole magnetic dipole and surface loop sources were used as the current sources. The presence of a tunnel causes a subsurface scattering of the field components created by the source. Ratioing of the measured responses enhanced the detection and location capability over that produced by each of the sources individually. 4 refs., 18 figs., 2 tabs.
As part of Sandia National Laboratories` (SNL) pollution prevention program a system is under development to track the movement of hazardous and radioactive materials from procurement, through use, to final disposition. The information provided by this system will improve the flow and enhance the quality of data, avoid duplication of effort, facilitate timely and accurate reporting, better support the information needs of various Environmental, Safety, and Health (ES&H) programs, and allow waste to be minimized more effectively. Such a comprehensive system will incorporate information from other sources and build upon existing databases. The component include the Chemical Information System/Material Safety Data Sheet (CIS/MSDS) system installed by AT&T Bell Laboratories (AT&T-BL) at SNL in Livermore, along with a barcode chemical waste tracking system already in operation at SNL in Albuquerque. Also being developed in Albuquerque are Process Waste Assessments, a radioactive material tracking system, and a radioactive/mixed waste tracking system. A SNL and AT&T-BL joint project is addressing how PWAs will link raw materials to waste streams. With a ``cradle-to-grave`` tracking system, it is possible to assess both financial and environmental life cycle costs. Once in place, this information will improve long-run efficiency and environmental protection, and provide benefits exceeding the initial demands placed upon personnel.
Knowledge of the solubility of gases in pure water and sodium chloride brine is required for the evaluation of gas-liquid behavior associated with numerous processes in the chemical, biological, and geological sciences and in chemical engineering. Modelling of multiphase flow and transport processes used to simulate fluid behavior in geological media requires suitable and accurate gas solubility data, especially when applied to potential nuclear waste repositories such as WIPP. This report contains a critical evaluation of data available in the literature and provides compiled data sets for the solubility of hydrogen, nitrogen, methane, and carbon dioxide gases in pure water and in sodium chloride brine. Mole fraction gas solubilities are presented as functions of temperature and pressure. To evaluate the influence of electrolyte content of the aqueous solution upon the gas solubility, Sechenov coefficients are provided for several concentrated sodium chloride solution. An estimate of the solubility of hydrogen in 5 N sodium chloride brine as a function of pressure exhibits a solubility at 40 MPa that is one fifth the value observed for pure water at the same pressure.
In this paper, a design methodology is presented for assessing drift stability for a potential high-level radioactive waste repository. Excavation stability is required during construction, emplacement, retrieval (if required) and closure phases to ensure worker health and safety, and to prevent development of potential pathways for radionuclide migration in the post-closure period. Requirements for the design, site conditions and stresses are considered in the methodology. Methods for evaluating empirical and analytical results in order to estimate ground support requirements are outlined.
Large computational physics codes are increasing in complexity as customers demand improved physics packages and more flexible algorithms and problem specifications. It is not uncommon for a code to exceed one hundred thousand lines of FORTRAN, and some codes are much larger. This poses a considerable challenge for program management. The Computational Physics Research and Development Division at Sandia National Laboratories is aggressively pursuing C++ as the language of choice for new coding efforts. We feel that we cannot meet the stringent customer requirements and delivery schedules we now face with either FORTRAN77 or Fortran-90. 8 refs., 3 tabs.
Cleaning, plating, and painting are chemically intensive processes that involve toxic and potentially carcinogenic materials that pose a significant threat to the environment. EPA/OSHA, the Clean Air Act, and the Montreal Protocol are forcing development of environmentally sound materials and processes. A review is given of the materials and processes that are under investigation that will minimize the environmental impact of these operations. 7 refs.
The Recirculating Linear Accelerator (RLA) is returning to operation with a new relativistic electron beam (REB) injector and a modified accelerating cavity. Upon completion of our pulsed-power test program, we will capture the injected beam on an Ion Focussed Regime (IFR) guiding channel in either a spiral or a closed racetrack drift tube. The relativistic beam will recirculate for four passes through two accelerating cavities, in phase with the ringing cavity voltage, and increase to 8--12 MeV before being extracted. We designed the METGLAS ribbon-wound core, inductively isolated, four-stage injector to produce beam parameters of 4 MeV. 10--20 kA, and 40--55 ns FWHM. The three-line radial cavity is being modified to improve the 1-MV accelerating pulse shape while an advanced cavity design study is in progress. This is a continuation of the Sandia National Laboratory program to develop compact, high-voltage gradient, linear induction accelerators. The RLA concept is based on guiding an injected REB with an IFR channel. This channel is formed from a plasma created with a low energy electron beam inside a beam line containing about 2 {times} 10{sup {minus}4} Torr of argon. The REB is injected onto the IFR channel and is transported down the beamline through a water dielectric accelerating cavity based on the ET-2 design. If the round-tip path of the beam matches the period of the cavity, the REB can be further accelerated by the ringing waveform on every subsequent pass. We have installed the new REB injector because we need a higher amplitude, longer duration., flat-topped pulse shape with a colder beam than that produced by the previous injector. We made extensive use of computer simulations in the form of network solver and electrostatic field stress analysis codes to aid in the design and modifications for the new RLA. The pulsed-power performance of the RLA injector and cavity and the associated driving hardware are discussed.
A major center with emphasis on validation of nondestructive inspection techniques for aging aircraft, the Aging Aircraft NDI Development and Demonstration Center (AANC), has been funded by the FAA at Sandia National Laboratories. The Center has been assigned specific tasks in developing techniques for the nondestructive inspection of static engine parts, assessing inspection reliability (POD experiments), developing test beds for nondestructive inspection validation, maintaining a FAA library of characterized aircraft structural test specimens, and leasing a hangar to house a high flight cycle transport aircraft for use as a full scale test bed. 3 refs.
This paper describes procedure used to produce a test-validated finite element model of a three-stage solid propellant booster system. A series of system-level modal tests were performed for several inert and live propellant configurations. Test-analysis models (TAMs) were used to provide pretest support of the live propellant system tests. Confidence in the model was established by a test-analysis correlation procedure. Optimization techniques were used to determine appropriate model updates. 11 refs., 8 figs., 3 tabs.
Soldering is often referred to as a mature technology whose fundamentals were established long ago. Yet a multitude of soldering problems persist, not the least of which are related to the wetting and spreading of solder. The Buff-Goodrich approach to thermodynamics of capillarity is utilized in a review of basic wetting principles. These thermodynamics allow a very compact formulation of capillary phenomena which is used to calculate various meniscus shapes and wetting forces. These shapes and forces lend themselves to experimental techniques, such as the sessile drop and the Wilhelmy plate, for measuring useful surface and interfacial energies. The familiar equations of Young, Wilhelmy, and Neumann are all derived with this approach. The force-energy duality of surface energy is discussed and the force method is developed and used to derive the Herring relations for anisotropic surfaces. The importance of contact angle hysteresis which results from surface roughness and chemical inhomogeneity is presented and Young's equation is modified to reflect these ever present effects. Finally, an analysis of wetting with simultaneous metallurigical reaction is given and used to discuss solder wetting phenomena. 60 refs., 13 figs.
Titanium dioxide (TiO{sub 2}) is a known photocatalyst for solar detoxification of water containing organic contaminants including PCB's and dioxins. Unfortunately, the UV light used by the photocatalyst only comprises about 4% of the strong spectrum. Metalloporphyrins strongly absorb in the visible and near infrared region. Using visible light, we have investigated Ni(II) uroporphyrin (NiUroP), Sn(IV)Cl{sub 2} uroporphyrin (SnUroP) and Sn(IV)Cl{sub 2} tetrakis(p-carboxyphenyl) porphyrin (SnTCPP) as possible enhancers of destruction of a model organic compound, salicylic acid (SA), by means of photosensitization of colloidal TiO{sub 2} particles. All three porphyrins are found to adsorb reversibly onto the colloidal TiO{sub 2} upon variation of pH. Adsorption of porphyrins results in the increased colloidal stability of fine TiO{sub 2} particles in the pH range 5--8. While NiUroP on TiO{sub 2} does not show any enhancement of photodestruction, the adsorption of SnUroP increases the destruction rate compared to that of the bare TiO{sub 2} surface. The effect of ambient oxygen on the observed photolability of the Sn porphyrins and enhancement of photodestruction of SA was also investigated. SnTCPP does not photodecompose upon illumination either in the presence or absence of TiO{sub 2}, but neither does it bind to the photocatalyst at pH 6. At pH 4.5 it adsorbs onto TiO{sub 2} but it also photodecompose at this pH. We are attempting to stabilize the adsorbed porphyrins by adding suitable peripheral substituents onto the porphyrin macrocycle. 27 refs., 6 figs.
We have designed and tested a system for applying a ramped vertical magnetic field for turning the electron beam in the IFR Recirculating Linear Accelerator. The field is highly uniform over two Gaussian beam radii, and can be adjusted for a large radial gradient for increased energy bandwidth. The system includes shielding of the current-carrying rods to protect the pulser from REB induced fields and to reduce the effect of REB images on the beam transport to negligible levels. The system has been tested on the IBEX accelerator with > 95% peak current transport and > 90% charge transport through a 90{degree} turn. 2 refs., 6 figs.
The cleaning efficiency of five alternative solvents for chlorofluorocarbons (CFCs) and chlorohydrocarbons (CHCs) used in the manufacture of certain electronic components was studied. These solvents were evaluated in the first phase of a two-phase program to remove various manufacturing contaminants such as oils, greases, mold release, and body oils. Results have shown that EXXATE 1000 and EC-7 were able to effectively remove these contaminants from copper board substrates. 4 refs., 5 figs., 1 tab.
Eight Gulf Coast salt domes have emerged as candidate sites for possible expansion of the Strategic Petroleum Reserve (SPR) to one billion barrels. Two existing SPR sites, Big Hill, TX, and Weeks Island, LA, are among the eight that are being considered. To achieve the billion barrel capacity, some 25 new leached caverns would be constructed, and would probably be established in two separate sites in Louisiana and Texas because of distribution requirements. Geotechnical factors involved in siting studies have centered first and foremost on cavern integrity and environmental acceptability, once logistical suitability is realized. Other factors have involved subsidence and flooding potential, loss of coastal marshlands, seismicity, brine injection well utility, and co-use by multiple operators. 5 refs., 11 figs., 2 tabs.
Hertel, E.S.; Chhabildas, L.C.; Yarrington, L.; Hill, S.A.
A series of numerical simulations has been performed using the multi-dimensional hydrodynamics code CTH to computationally determine a ballistic limit for a Whipple bumper shield. The ballistic limit is generally characterized as a critical diameter such that particle diameters greater than the ballistic limit will generate debris clouds that will penetrate the rear wall and particle diameters less than the ballistic limit will not. The particular shield design used for these analyses is defined as a 1.27 mm bumper, a 102 mm void space, and a 3.18 mm rear wall. Since debris shape is expected to be a contributing factor in the impact phenomena, two different shapes are considered for the numerical simulations. The particle shapes considered were flat plates of constant 1 mm thickness and varying diameters and spheres of varying diameters. The critical diameter (ballistic limit) was determined over the velocity range 4 km/s to 15 km/s for both geometries. 13 refs., 2 figs.
In response to a request from the US Government, Sandia National Laboratories has developed an instrumentation system to monitor the conditions along an underwater, rotating drive shaft. It was desired to study the structural integrity and signal acquisition capabilities of the Shaft Instrumentation System (SIS) in an environment which closely simulates the actual deployment conditions. In this manner, the SIS response to ill-defined conditions, such as flow field turbulence or temperature fluctuations, could be determined. An Underwater Spin Facility was developed in order to verify the operation of the instrumentation and telemetric data acquisition system in a combined environment of external pressure, transient axial loads and centrifugal force. The main components of the Underwater Spin Facility are a large, five foot diameter pressure vessel, a dynamically sealed shaft, a drive train assembly and a shaker table interface which is used to apply the axial loads. This paper presents a detailed description of the design of the Underwater Spin Facility. It also discusses the SIS certification test program in order to demonstrate the successful performance of the Underwater Spin Facility. 8 refs., 10 figs.
There are three aspects to an environmentally safe battery. The first deals with the manufacturing process, the second with the use of environmentally friendly materials, and the third with the disposal and/or recycling of spent units. In this paper, several ongoing programs at Sandia National Laboratories that relate to the environmentally conscious manufacturing of batteries, are discussed. The solvent substitution/elimination program is a two-pronged effort, aimed at identifying new solvents which are compatible with the environment, while at the same time developing dry process cleaning technology. The joining program is evaluating new solvents for flux removal as well as the development of fluxless soldering processes. In the area of welding, new cleaning processes are under study. Chemical microsensors are under development that are capable of identifying and quantifying single chemical species. These sensors have been used to monitor and improve processes using toxic/hazardous solvents. 1 ref., 1 fig.
Phased-array antenna systems are well known for rapid beam steering and their ability to bring high power to the target. Such systems are also quite complex and heavy, which have limited their usefulness. The issues of weight, size, power use, and complexity have been addressed through a system named COMPASS (Coherent Optical Monolithic Phased Array Steering System). All phased-array antenna systems need: (1) small size; (2) low power use; (3) high-speed beam steering; and (4) digitally-controlled phase shifting. COMPASS meets these basic requirements, and provides some very desirable additional features. These are: (1) phase control separate from the transmit/receive module; (2) simple expansion to large arrays; (3) fiber optic interconnect for reduced sensitivity to EMI; (4) an intrinsically radiation-hard GaAs chip; and (5) optical power provided by a commercially available continuous wave (CW) laser. 4 refs., 8 figs.
Titanium alloys offer desirable properties that make them attractive candidates for tribological applications. Their surface-related properties, however, such as coefficient of friction and wear rate, are less than optimum and must be improved by surface modification. To increase the tribological properties of Ti-6Al-4V, a high temperature ion implantation method, employing a high current density beam (e.g., 500 {mu}A/cm{sup 2}) of nitrogen (N) ions is being developed, where surface temperatures greater than 1000{degrees}C can be obtained. A systematic study was performed with N implantation at temperatures from 400{degrees} to >1000{degrees}C, and to a range of doses from 0.1--1.0{times}10{sup 18} N{sub 2}{sup +}--N{sup +}/cm{sup 2}. Microstructure characterization by Rutherford Backscattering Spectroscopy (RBS) and Glancing Incidence X-ray Diffraction (GID) was performed to determine N distribution and compound formation. RBS analysis showed enhanced N penetrations (i.e., greater than 0.3 {mu}m) for the 800{degrees} and 1000{degrees}C implantations, with the deepest penetration (about 3.5 atomic percent N remaining at 0.75 {mu}m) for the 1000{degrees}C treatment. GID indicated TiN and Ti{sub 2}N concentrations were the greatest for the 800{degrees}C implantation treatment. 11 refs., 4 figs.
The debonding rates of H-passivated P and As in silicon have been observed to be very sensitive to the concentration of majority and minority charge carriers. A theoretical study of the stable and metastable configurations of the {l brace}P,H{r brace} and {l brace}As,H{r brace} pairs in the 0 and +1 charge states has been carried out at the near-ab-initio Hartree-Fock level. These calculations show that the lowest-energy configuration in the 0 charge state is the highest-energy configuration in the +1 charge state and vice-versa. This bistability of donor-hydrogen pairs implies that H cannot remain in place upon change of charge state, whether 0 {r arrow} +1 or +1 {r arrow} 0. Quantitative differences between the P and the As cases are qualitatively consistent with the observed differences in the temperature dependence of the debonding rates of {l brace}P,H{r brace} and {l brace}As,H{r brace}. 14 refs., 1 fig.
The usefulness of neutron radiography as a nondestructive engineering tool is heavily dependent on how a neutron reaches the image plane. Neutron interactions such as scattering and absorption, within a neutron radiography facility or a test part, affect the contrast of the resulting image generated by the process. It is important that the radiographer has a general understanding of how neutrons interact with matter to produce a quality image utilizing a neutron beam. 4 refs.
The distribution of copper aluminum thin films is examined with respect to how the copper can influence electromigration behavior. Al-Cu thin films annealed in the single phase region, to just below the solvus {theta}-phase Al{sub 2}Cu precipitates at the aluminum grain boundaries. The grain boundaries between precipitates are depleted in copper. Al-Cu thin films heat treated at lower temperatures, within the two phase region, also have {theta}-phase precipitates at the grain boundaries but the aluminum grain boundaries continuously become enriched in copper, perhaps due to the formation of a thin coating of {theta}-phase at the grain boundary. Here, it is proposed that electromigration behavior of aluminum is improved by adding copper because the {theta}-phase precipitates may hinder aluminum diffusion along the grain boundaries. It was also found that resistivity of Al-Cu thin films decrease during accelerated electromigration testing prior to failure. Pure Al films did not exhibit this behavior. The decrease is resistivity is attributed to the redistribution of copper from the aluminum grain matrix to the {theta}-phase precipitates growing at the grain boundaries thereby reducing the number of defects in the microstructure. 34 refs., 12 figs.
The large deformation elastic response of a plane woven Kevlar fabric is investigated analytically and experimentally. The analysis assumes the undeformed geometry to be a sequence of interlaced arcs of circles which reverse at each yarn midpoint, ad each yarn is modeled as an extensible elastical subject to certain compatibility conditions. Deflection-force relations for the fabric are determined in terms of the initial weave geometry and the elastic properties of the individual yarns. The theoretical results agree well with the results of experiments performed on a fabric woven from 400 denier Kevlar yarns under conditions of uniaxial loading in both warp and fill directions. 13 refs., 4 figs.