Publications

A novel technique has been developed for the synthesis of homogeneous, weakly agglomerated highly filterable Pb(Zr, Ti)O{sub 3} (PZT) powders. PZT 95/5 based ceramics were fabricated from these powders to determine interrelationships among microstructure, dielectric properties and pressure induced ferroelectric (FE) to antiferroelectric (AFE) phase transitions. Initial measurements indicate that microstructure has a substantial effect on hydrostatic depoling characteristics. While smaller grain size materials and higher switching pressures, subtleties in microstructure, which may include entrapped porosity, resulted in a more diffuse depoling characteristic. In addition, greater than 90% dense materials were obtained at process temperatures as low at 900{degrees}C. were only 30% of the values of PZT 95/5 fired at 1300{degrees}C, the dielectric constants of the 900{degrees}C materials were almost a factor of two higher. Backscattered electron Kikuchi pattern analysis determined that adjacent, nonlinear, irregularly shaped domain structures observed by electron channel imaging were 109{degrees} domains.

Specimens were tested from four thermal-mechanical units, namely Tiva Canyon (TCw), Paintbrush Tuff (PTn), and two Topopah Spring units (TSw1 and TSw2), and from two lithologies, i.e., welded devitrified (TCw, TSw1, TSw2) and nonwelded vitric tuff (PTn). Thermal conductivities in W(mk){sup {minus}1} averaged over all boreholes, ranged (depending upon temperature and saturation state) from 1.2 to 1.9 for TCw, from 0.4 to 0.9 for PTn, from 1.0 to 1.7 for TSw1, and from 1.5 to 2.3 for TSw2. Mean coefficients of thermal expansion were highly temperature dependent and values, averaged over all boreholes, ranged (depending upon temperature and saturation state) from 6.6 {times} 10{sup {minus}6} to 49 {times} 10{sup {minus}6} C{sup {minus}1} for TCw, from the negative range to 16 {times} 10{sup {minus}6} {center_dot} {degree}C{sup {minus}1} for PTn, from 6.3 {times} 10{sup {minus}6} to 44 {times} 10{sup {minus}6} C{sup {minus}1} for TSw1, and from 6.7 {times} 10{sup {minus}6} to 37 {times} 10{sup {minus}6} {center_dot} {degree}C{sup {minus}1} for TSw2. Mean values of thermal capacitance in J/cm{sup 3}K (averaged overall specimens) ranged from 1.6 J to 2.1 for TSw1 and from 1.8 to 2.5 for TSw2. In general, the lithostratigraphic classifications of rock assigned by the USGS are consistent with the mineralogical data presented in this report.

Under the sponsorship of the US Department of Energy`s Office of Utility Technologies, the Energy Storage Systems Analysis and Development Department at Sandia National Laboratories (SNL) contracted Frost and Sullivan to conduct a market feasibility study of energy storage systems. The study was designed specifically to quantify the battery energy storage market for utility applications. This study was based on the SNL Opportunities Analysis performed earlier. Many of the groups surveyed, which included electricity providers, battery energy storage vendors, regulators, consultants, and technology advocates, viewed battery storage as an important technology to enable increased use of renewable energy and as a means to solve power quality and asset utilization issues. There are two versions of the document available, an expanded version (approximately 200 pages, SAND97-1275/2) and a short version (approximately 25 pages, SAND97-1275/1).

The DEBRIS Late Phase Melt Progression Model is an assembly of models, embodied in a computer code, which is designed to treat late-phase melt progression in dry rubble (or debris) regions that can form as a consequence of a severe core uncover accident in a commercial light water nuclear reactor. The approach is fully two-dimensional, and incorporates a porous medium modeling framework together with conservation and constitutive relationships to simulate the time-dependent evolution of such regions as various physical processes act upon the materials. The objective of the code is to accurately model these processes so that the late-phase melt progression that would occur in different hypothetical severe nuclear reactor accidents can be better understood and characterized. In this report the models and correlations incorporated and used within the current version of DEBRIS are described. These include the global conservation equations solved, heat transfer and fission heating models, melting and refreezing models (including material interactions), liquid and solid relocation models, gas flow and pressure field models, and the temperature and compositionally dependent material properties employed. The specific models described here have been used in the experiment design analysis of the Phebus FPT-4 debris-bed fission-product release experiment. An earlier DEBRIS code version was used to analyze the MP-1 and MP-2 late-phase melt progression experiments conducted at Sandia National Laboratories for the US Nuclear Regulatory Commission.

Geothermal, or ground-source, heat pumps (GHP) are much more efficient than air-source units such as conventional air conditioners. A major obstacle to their use is the relatively high initial cost of installing the heat-exchange loops into the ground. In an effort to identify drivers which influence installation cost, a number of site visits were made during 1996 to assess the state-of-the-art in drilling for GHP loop installation. As an aid to quantifying the effect of various drilling-process improvements, we constructed a spread-sheet based on estimated time and material costs for all the activities required in a typical loop-field installation. By substituting different (improved) values into specific activity costs, the effect on total project costs can be easily seen. This report contains brief descriptions of the site visits, key points learned during the visits, copies of the spread-sheet, recommendations for further work, and sample results from sensitivity analysis using the spread-sheet.

Galerkin approximations and finite element methods for operator equations of the form Lu = f play an important role in the theory of numerical differential equations. This report summarizes some of the approximation-theoretic and numerical issues encountered in solving operator equations of the form Lu = f. Particular emphasis is placed on Galerkin and finite element approximations using multiwavelets. Examples are used to illustrate some of the issues.

Determining the quantity of deuterium in an erbium deuteride (ErD{sub 2}) film is essential for assessing the quality of the hydriding process but is a challenging measurement to make. First, the ideal gas law cannot be applied directly due to high temperature (950{degrees}C) and low temperature (25{degrees}C) regions in the same manifold. Additionally, the metal hydride does not release all of the deuterium rapidly upon heating and metal evaporation occurs during extended heating periods. Therefore, the method developed must provide a means to compensate for temperature inhomogeneities and the amount of deuterium retained in the metal film while heating for a minimal duration. This paper presents two thermal desorption methods used to evaluate the kinetics and equilibria of the deuterium desorption process at high temperatures (950{degrees}C). Of primary concern is the evaluation of the quantity of deuterium remaining in these films at the high temperature. A multiple volume expansion technique provided insight into the kinetics of the deuterium evolution and metal evaporation from the film. Finally a repeated pump-down approach yielded data that indicated approximately 10% of the deuterium is retained in the metal film at 950{degrees}C and approximately 1 Torr pressure. When the total moles of deuterium determined by this method were divided by the moles of erbium determined by ICP/AES, nearly stochiometric values of 2:1 were obtained for several erbium dideuteride films. Although this work presents data for erbium and deuterium, these methods are applicable to other metal hydrides as well.

There is an active literature on the simulation of cutting processes through finite element methods. Such efforts are motivated by the enormous economic importance of machining processes and the desire to adjust processes so as to optimize product and throughput, but suffer from some difficulties inherent to the finite element method. An alternative approach, which appears to overcome most of those difficulties, is that of Smooth Particle Hydrodynamics (SPH).Though some finite element work is reviewed here, the focus of this paper is on the demonstration of the SPH technique of to simulate orthogonal cutting.

This report contains the notes from the second session of the 1997 IEEE Nuclear and Space Radiation Effects Conference Short Course on Applying Computer Simulation Tools to Radiation Effects Problems. Part A discusses the physical phenomena modeled in radiation transport codes and various types of algorithmic implementations. Part B gives examples of how these codes can be used to design experiments whose results can be easily analyzed and describes how to calculate quantities of interest for electronic devices.

To properly determine what is needed in a structural health monitoring system, actual operational structures need to be studied. We have found that to effectively monitor the structural condition of an operational structure four areas must be addressed: determination of damage-sensitive parameters, test planning, information condensation, and damage identification techniques. In this work, each of the four areas has been exercised on an operational structure. The structures studied were all be wind turbines of various designs. The experiments are described and lessons learned will be presented. The results of these studies include a broadening of experience in the problems of monitoring actual structures as well as developing a process for implementing such monitoring systems.

As part of the joint U.S. and Republic of Kazakstan nuclear Material Protection, Control, and Accounting (MPC{ampersand}A) program, the U.S. Department of Energy (DOE) is providing assistance at four nuclear facilities in Kazakstan. These facilities are the Ulba Metallurgical Plant, the National Nuclear Center (NNC) Institute of Atomic Energy at Kurchatov (IAE-K), the Mangyshlak Atomic Energy Complex (BN-350) Reactor, and the NNC Institute of Atomic Energy at Almaty (IAE-A). This paper describes the DOE MPC{ampersand}A physical protection program at each of the facilities.

Remote monitoring is not a new technology, and its application to safeguards relevant activities has been examined for a number of years. On behalf of the US Department of Energy and international partners, remote monitoring systems have been emplaced in nuclear facilities and laboratories in various parts of the world. The experience gained from these field trials of remote monitoring systems has shown the viability of the concept of using integrated monitoring systems. Although a wide variety of sensors has been used in the remote monitoring field trials conducted to date, the possible range of instrumentation that might be used has scarcely been touched. As the technology becomes widespread, large amounts of data will become available to inspectors responsible for safeguards activities at the sites. Effective use of remote monitoring will require processing, archiving, presenting, and assessing of these data. To provide reasonable efficiency in the application of this technology, data processing should be done in a careful and organized manner. The problem will be not an issue of poring over scant records but of surviving under a deluge of information made possible by modern technology. Fortunately, modern technology, which created the problem of the data glut, is available to come to the assistance of those inundated by data. Apart from the technological problems, one of the most important aspects of remote monitoring is the potential constraint related to the transmission of data out of a facility or beyond national borders. Remote monitoring across national borders can be seriously considered only in the context of a comprehensive, transparent, and open implementation regime.

Because of the need to significantly extend the lifetimes of weapons, and because of potential implications of environmental O-ring failure on degradation of critical internal weapon components, the authors have been working on improved methods of predicting and verifying O-ring lifetimes. In this report, they highlight the successful testing of a new predictive method for deriving more confident lifetime extrapolations. This method involves ultrasensitive oxygen consumption measurements. The material studied is an EPDM formulation use for the environmental O-ring the W88. Conventional oven aging (155 C to 111 C) was done on compression molded sheet material; periodically, samples were removed from the ovens and subjected to various measurements, including ultimate tensile elongation, density and modulus profiles. Compression stress relaxation (CSR) measurements were made at 125 C and 111 C on disc shaped samples (12.7 mm diameter by 6 mm thick) using a Shawbury Wallace Compression Stress Relaxometer MK 2. Oxygen consumption measurements were made versus time, at temperatures ranging from 160 C to 52 C, using chromatographic quantification of the change in oxygen content caused by reaction with the EPDM material in sealed containers.

Task T-222 of the International Thermonuclear Experimental Reactor (ITER) program addresses the manufacturing and testing of permanent components for use in the ITER divertor. Thermalhydraulic and critical heat flux performance of the heat sinks proposed for use in the divertor vertical target are part of subtask T-222.4. As part of this effort, two single channel, medium scale, bare copper alloy, hypervapotron mockups were designed, fabricated, and tested using the EB-1200 electron beam system. The objectives of the effort were to develop the design and manufacturing procedures required for construction of robust high heat flux (HHF) components, verify thermalhydraulic, thermomechanical and critical heat flux (CHF) performance under ITER relevant conditions, and perform analyses of HHF data to identify design guidelines and failure criteria and possibly modify any applicable CHF correlations. The design, fabrication, and finite element modeling of two types of hypervapotrons are described; a common version already in use at the Joint European Torus (JET) and a new attached fin design. HHF test data on the attached fin hypervapotron will be used to compare the CHF performance under uniform heating profiles on long heated lengths with that of localized, highly peaked, off nominal profiles.

Federal R and D must be principally focused on solving public problems that the marketplace is failing to address. With few exceptions programs must be supported by roadmaps that show how the R and D is linked to public outcomes. Federal R and D and those who perform it must be judged in terms of the public outcomes. The overarching issues of federal R and D policy, what it should address, how to manage it, who should perform it, how to perform it, what works best, etc. are highly complex and lack a strong theoretical foundation. (In fact, the linear, assembly-line model used by policymakers is wrong.) It is time that policymakers recognize and acknowledge the uncertainty of their work and conduct a wide array of policy experiments (the authors consider SEMATECH such an experiment) that are supported by public outcome metrics. In addition to making federal R and D better address public needs, such an approach to policy making could raise the public`s interest in T and S policy. Of course, as in any experiment the results may be measured and if failures aren`t observed, it is likely that policies lack vision and imagination. It is time to abandon the budget driven federal R and D system where performers of federal R and D are treated as constituents, and replace it with a public problem--public outcome driven system where public problems are prioritized and the budget is distributed to agencies according to these priorities.

Contacts from the functional switch assembly have been examined for a series of MC2969 stronglinks varying from 9 to 14 years of age. Wear tracks are apparent on the contacts as a result of oxide removal by wiping action as the switch is exercised. Typical contaminants observed on the contacts include C, O, S, Cl, F and Si, all of which vary with position on the contacts. All of the contacts show segregation of Ag into the near-surface region. Measurement of the local contact resistance on the ends of the contacts provide resistance values that are reasonable for this material, but with variation among contacts as a result of changes in the local surface chemistry.

Evaluation of flooded lead-acid, Valve Regulated Lead-Acid (VRLA), and advanced batteries is being performed in the power sources testing labs at Sandia National Laboratories (SNL). These independent, objective tests using computer-controlled testers capable of simulating application-specific test regimes provide critical data for the assessment of the status of these technologies. Several different charge/discharge cycling regimes are performed. Constant current and constant power discharge tests are conducted to verify capacity and measure degradation. A utility test is imposed on some units which consists of partial depths of discharge (pulsed constant power) cycles simulating a frequency regulation operating mode, with a periodic complete discharge simulating a spinning reserve test. This test profile was developed and scaled based on operating information from the Puerto Rico Electric Power Authority (PREPA) 20 MW battery energy storage system. Another test conducted at SNL is a photovoltaic battery life cycle test, which is a partial depth of discharge test (constant current) with infrequent complete recharges that simulates the operation of renewable energy systems. This test profile provides renewable system designers with critical battery performance data representative of field conditions. This paper will describe the results of these tests to date, and include analysis and conclusions.

Maximizing the reclamation/recycle of electric-vehicle (EV) batteries is considered to be essential for the successful commercialization of this technology. Since the early 1990s, the US Department of Energy has sponsored the ad hoc advanced battery readiness working group to review this and other possible barriers to the widespread use of EVs, such as battery shipping and in-vehicle safety. Regulation is currently the main force for growth in EV numbers and projections for the states that have zero-emission vehicle (ZEV) programs indicate about 200,000 of these vehicles would be offered to the public in 2003 to meet those requirements. The ad hoc Advanced Battery Readiness Working Group has identified a matrix of battery technologies that could see use in EVs and has been tracking the state of readiness of recycling processes for each of them. Lead-acid, nickel/metal hydride, and lithium-ion are the three EV battery technologies proposed by the major automotive manufacturers affected by ZEV requirements. Recycling approaches for the two advanced battery systems on this list are partly defined, but could be modified to recover more value from end-of-life batteries. The processes being used or planned to treat these batteries are reviewed, as well as those being considered for other longer-term technologies in the battery recycling readiness matrix. Development efforts needed to prepare for recycling the batteries from a much larger EV population than exists today are identified.

Effective communication among air safety professionals is only as good as the information being communicated. Data sharing cannot be effective unless the data are relevant to aviation safety problems, and decisions based on faulty data are likely to be invalid. The validity of aviation safety data depends on satisfying two primary characteristics. Data must accurately represent or conform to the real world (conformance), and it must be relevant or useful to addressing the problems at hand (utility). The FAA, in efforts to implement the Safety Performance Analysis System (SPAS), identified significant problems in the quality of the data which SPAS and FAA air safety professionals would use in defining the state of aviation safety in the US. These finding were reinforced by Department of Transportation Inspector General and General Accounting Office investigations into FAA surveillance of air transport operations. Many recent efforts to improve data quality have been centered on technological solutions to the problems. They concentrate on reducing errors in the data (conformance), but they cannot adequately address the relationship of data to need (utility). Sandia National Laboratories, working with the FAA`s Airport and Aircraft Safety Research and Development Division and the Flight Standards Service, has been involved in four programs to assist FAA in addressing their data quality problems. The Sandia approach has been data-driven rather than technology-driven. In other words, the focus has been on first establishing the data requirements by analyzing the FAA`s surveillance and decision-making processes. This process analysis looked at both the data requirements and the methods used to gather the data in order to address both the conformance and utility problems inherent in existing FAA data systems. This paper discusses Sandia`s data quality programs and their potential improvements to the safety analysis processes and surveillance programs of the FAA.

Ceramic materials are used extensively in non-nuclear components in the weapons stockpile including neutron tubes, firing sets, radar, strong link and weak link assemblies, batteries, and current/voltage stacks. Ceramics also perform critical functions in electronics, passively as insulators and actively as resistors and capacitors. Glass and ceramic seals also provide hermetic electrical feedthroughs in connectors for many weapons components. The primary goal of the ceramic material lifetime prediction program is to provide the enhanced surveillance program with the capability to specify the reliability and lifetimes of glass and ceramic-containing components under conditions typical of the stockpile environment. The authors have studied the reliability and subcritical crack growth (SCG) behavior of 94% alumina (Al{sub 2}O{sub 3}), which is likely the most common ceramic in the stockpile. Measurements have been made on aluminas manufactured by four war reserve qualified vendors (Coors, Wesgo, AlSiMag, and Diamonite). These materials are expected to be representative of typical product obtained from vendors who have supplied alumina for weapons components during the past several decades.

The solid lubricant used most extensively in strong links throughout the enduring stockpile contains MoS{sub 2}, which is known to react with oxygen and water vapor resulting in a change in the material`s friction and wear behavior. The authors have examined the frictional behavior of this lubricant as a function of oxidation, in support of efforts to quantify the impact of changes in the material on the dynamic behavior of the MC2969 strong link. Their results show that the friction response of oxidized lubricant is strongly influenced by the amount of burnishing performed on the lubricant after deposition. Low levels of burnish leave a thick film, of which only the near surface degrades during oxidation. Rapid wear of the oxidized material leaves a surface whose properties are the same as non-oxidized material. Higher levels of burnish leave a thinner film of lubricant such that the entire film may be oxidized. The friction coefficient on this surface reaches a steady state value greater than that of non oxidized material. In addition to these fundamental differences in steady state behavior, they have shown that the initial friction coefficient on oxidized surfaces is related to the amount of sulfide converted to sulfate, regardless of the oxidation conditions used. Measurements on parts returned from the stockpile show that the friction behavior of aged hardware is consistent with the behavior observed on controlled substrates containing thin lubricant films.

Information flowing on communication buses is ordinarily ``non-random`` in the sense that data entities are not equally likely and independent. This is because they have relationships to each other and to physical occurrences to which they may be responding. Random data would convey no information or meaning. From a different viewpoint, there can be applications for creating randomness characteristics, and four of these are described in this paper. Two examples derive from cryptology and the other two from safety. One cryptology application described is the generation of random numbers for use as, for example, keys, hash functions, nonces, and seeds. The other is for inter-message ``padding`` to resist traffic analysis by masking when data are being transmitted and when the channel is conveying no information. One of the safety applications described is the ``unique signal`` approach used in modern nuclear weapon electrical safety. The other is the use of unique signals as non-weapon critical-operation control functions. Both of these safety applications require provisions to help assure randomness characteristics in any inadvertently occurring inputs. In order to satisfy these cryptology and safety needs, communication strategies are described that generate or selectively encourage independent (unrelated) symbols or messages.

The employment of Laser Beam Welding (LBW) for many traditional arc welding applications is often limited by the inability of LBW to compensate for variations in the weld joint gap. This limitation is associated with fluctuations in the energy transfer efficiency along the weld joint. Since coupling of the laser beam to the workpiece is dependent on the maintenance of a stable absorption keyhole, perturbations to the weld pool can lead to decreased energy transfer and resultant weld defects. Because energy transfer in arc welding does not similarly depend on weld pool geometry, it is expected that combining these two processes together will lead to an enhanced fusion welding process that exhibits the advantages of both arc welding and LBW. Laser assisted non-consumable arc welds have been made on thin section aluminum. The welds combine the advantages of arc welding and laser welding, with enhanced penetration and fusion zone size. The use of a pulsed Nd:YAG laser with the combined process appears to be advantageous since this laser is effective in removing the aluminum oxide and thereby allowing operation with the tungsten electrode negative. The arc appears to increase the size of the weld and also to mitigate hot cracking tendencies that are common with the pulsed Nd:YAG laser.

In support of efforts to model the performance of the MC2969 strong link for stockpile life extension, the kinetics of oxidation of the MoS{sub 2} based solid lubricant coating have been determined. The lubricant oxidation is primarily influenced by the extent of burnishing of the coating after application and curing. The activation energy for lubricant oxidation is low and agrees well with reported values for MoS{sub 2} coatings and particles. The type of substrate material and the amount of H{sub 2}O vapor present have little influence on the oxidation kinetics, but do affect the chemical species found on the surface, including sulfate species which enhance substrate corrosion. The analysis of field returned hardware shows oxidation levels within the range of those obtained throughout the oxidation study.

This report addresses the problem of selection of lidar parameters, namely wavelengths for absorption lidar and excitation fluorescence pairs for fluorescence lidar, for optimal detection of species. Orthogonal spectra and cross sections are used as mathematical representations which provide a quantitative measure of species distinguishability in mixtures. Using these quantities, a simple expression for the absolute error in calculated species concentration is derived and optimization is accomplished by variation of lidar parameters to minimize this error. It is shown that the optimum number of wavelengths for detection of a species using absorption lidar (excitation fluorescence pairs for fluorescence lidar) is the same as the number of species in the mixture. Each species present in the mixture has its own set of optimum wavelengths. There is usually some overlap in these sets. The optimization method is applied to two examples, one using absorption and the other using fluorescence lidar, for analyzing mixtures of four organic compounds. The effect of atmospheric attenuation is included in the optimization process. Although the number of optimum wavelengths might be small, it is essential to do large numbers of measurements at these wavelengths in order to maximize canceling of statistical errors.