Publications

This talk is about leadership. Leaders are people at every level in an organization who believe in change and are energized by it. They understand the difficult realities of competitive existence. They motivate and challenge. They provide positive reinforcement -- but are never satisfied with their achievements because opportunities for further improvement are never exhausted. Today, leadership is more important than ever because operating environments are changing at an unprecedented rate. The causes are geopolitical, economic, technological, etc. In fact, everything we know about nature tells us that change is inevitable. History shows quite clearly that human progress is not possible without change. Yet, humans crave stability and permanence. As a consequence, success often leads to complacency. But, demise is inevitable for those who protect the status quo. There exists a growing national awareness that global competitive pressures are forcing on American industry the need for ever higher levels of performance. And, similar forces are necessitating improved performance in DOE's nuclear weapons complex. Today, quality takes on a much larger meaning than it has traditionally. It is attention to cost, schedule and product performance that characterize the modern Quality ethic. This paper discusses the manager's role and the new Quality philosophy. 11 figs.

Coupled thermal-structural finite element calculations of a reflux pool-boiler solar receiver were performed to characterize the operating stresses and to address issues affecting the service life of the receiver. Analyses performed using shell elements provided information for receiver material selection and design optimization. Calculations based on linear elastic fracture mechanics principles were performed using continuum elements to assess the vulnerability of a seam-weld to fatigue crack growth. All calculations were performed using ABAQUS, a general purpose finite element code, and elements specifically formulated for coupled thermal-structural analysis. Two materials were evaluated: 316L SS and Haynes 230 alloys. The receiver response was simulated for a combination of structural and thermal loads that represent the startup and operating conditions of the receiver. For both materials, maximum stresses in the receiver developed shortly after startup due to uneven temperature distribution across the receiver surface. The largest effective stress was near yield in the 316L SS receiver and below 39 percent of yield in the Haynes 230 receiver. The calculations demonstrated that stress reductions of over 25 percent could be obtained by reducing the aft dome thickness to one closer to the absorber. The fatigue calculations demonstrated that the stress distribution near the seam-weld notch depends primarily on the structural load created by internal pressurization of the receiver rather than the thermal, indicating that the thermal loads can be neglected when assessing the stress intensity near the seam-weld notch. The stress intensity factor, computed using the J-integral method and crack opening-displacement field equations, was significantly below the fatigue threshold for most steels. The calculations indicated that the weld notch was always loaded in compression, a condition which is not conducive to fatigue crack growth. 15 refs., 30 figs., 3 tabs.

Algorithms for the authentication of byte sequences are described. The algorithms are designed to authenticate data in the Storage, Retrieval, Analysis, and Display (SRAD) Test Data Archive of the Radiation Effects and Testing Directorate (9100) at Sandia National Laboratories, and may be used in similar situations where authentication of stored data is required. The algorithms use a well-known error detection method called the Cyclic Redundancy Check (CRC). When a byte sequence is authenticated and stored, CRC bytes are generated and attached to the end of the sequence. When the authenticated data is retrieved, the authentication check consists of processing the entire sequence, including the CRC bytes, and checking for a remainder of zero. The error detection properties of the CRC are extensive and result in a reliable authentication of SRAD data.

Monitoring wellhead pressure evolution is the best method of detecting crude oil leaks in SPR caverns while oil/brine interface depth measurements provide additional insight. However, to fully utilize the information provided by these interface depth measurements, a thorough understanding of how the interface movement corresponds to cavern phenomena, such as salt creep, crude oil leakage, and temperature equilibration, as well as to wellhead pressure, is required. The time evolution of the oil/brine interface depth is a function of several opposing factors. Cavern closure due to salt creep and crude oil leakage, if present, move the interface upward. Brine removal and temperature equilibration of the oil/brine system move the interface downward. Therefore, the relative magnitudes of these factors determine the net direction of interface movement. Using a mass balance on the cavern fluids, coupled with a simplified salt creep model for closure in SPR caverns, the movement of the oil/brine interface has been predicted for varying cavern configurations, including both right-cylindrical and carrot-shaped caverns. Three different cavern depths and operating pressures have been investigated. In addition, the caverns were investigated at four different points in time, allowing for varying extents of temperature equilibration. Time dependent interface depth changes of a few inches to a few feet were found to be characteristic of the range of cases studied. 5 refs, 19 figs., 1 tab.

In two earlier reports, we derived a time-temperature-dose rate superposition methodology, which, when applicable, can be used to predict cable degradation versus dose rate, temperature and exposure time. This methodology results in long-term predictive capabilities at the low dose rates appropriate to ambient nuclear power plant aging environments. The methodology was successfully applied to numerous important cable materials used in nuclear applications and the extrapolated predictions were verified by comparisons with long-term (7 to 12 year) results for similar or identical materials aged in nuclear environments. In this report, we test the methodology on three crosslinked polyolefin (CLPO) and two ethylene propylene rubber (EPR) cable insulation materials. The methodology applies to one of the CLPO materials and one of the EPR materials, allowing predictions to be made for these materials under low dose-rate, low temperature conditions. For the other materials, it is determined that, at low temperatures, a decrease in temperature at a constant radiation dose rate leads to an increase in the degradation rate for the mechanical properties. Since these results contradict the fundamental assumption underlying time-temperature-dose rate superposition, this methodology cannot be applied to such data. As indicated in the earlier reports, such anomalous results might be expected when attempting to model data taken across the crystalline melting region of semicrystalline materials. Nonetheless, the existing experimental evidence suggests that these CLPO and EPR materials have substantial aging endurance for typical reactor conditions. 28 refs., 26 figs., 3 tabs.

Effective sealing of the Waste Isolation Pilot Plant (WIPP) shafts will be required to isolate defense-generated transuranic wastes from the accessible environment. Shafts penetrate water-bearing hard rock formations before entering a massive creeping-salt formation (Salado) where the WIPP is located. Short and long-term seals are planned for the shafts. Short-term seals, a composite of concrete and bentonite, will primarily be located in the hard rock formations separating the water-bearing zones from the Salado Formation. These seals will limit water flow to the underlying long-term seals in the Salado. The long-term seals will consist of lengthly segments of initially unsaturated crushed salt. Creep closure of the shaft will consolidate unsaturated crushed salt, thereby reducing its permeability. However, water passing through the upper short-term seals and brine inherent to the salt host rock itself will eventually saturate the crushed salt and consolidation could be inhibited. Before saturating, portions of the crushed salt in the shafts are expected to consolidate to a permeability equivalent to the salt host rock, thereby effectively isolating the waste from the overlying water-bearing formations. A phenomenological model is developed for the coupled mechanical/hydrologic behavior of sealed WIPP shafts. The model couples creep closure of the shaft, crushed salt consolidation, and the associated reduction in permeability with Darcy's law for saturated fluid flow to predict the overall permeability of the shaft seal system with time. 17 refs., 6 figs., 1 tab.

The Strategic Petroleum Reserve (SPR), a 600 million barrel crude oil reserve stored primarily in caverns leached in Gulf Coast salt domes, is maintained by the US Department of Energy (DOE). As part of a continuing program to monitor and characterize changes in the oil stored in the reserve, SPR caverns are periodically sampled at varying depths. Several different kinds of samples are withdrawn including pressurized samples, which enable a determination of the oil's vapor pressure and gas/oil ratio. These two parameters are particularly important to drawdown strategies because if the oil contains significant amounts of gas (therefore having a high vapor pressure and gas/oil ratio), additional equipment and decreased removal rates may be required during drawdown. Past pressurized sampling data was wrought with inconsistencies due to improper pressurized sampling and sample analysis techniques. This report documents the findings of an investigation taken to determine the source of the problems in the existing pressurized sampling and sample analysis methods and to establish reliable and cost effective methods of performing these tasks. In particular, flow-through pressurized sampling technology was found to be the most appropriate method of obtaining reliable samples. The gravity transfer method was found to be the most reliable method of moving the sample from the flow-through tool to a transportation container. In regards to sample analysis, it is recommended that gas chromatography replace the antiquated Podbielniak method, that the gas/oil ratio be measured via standard techniques rather than calculated using equations of state, and that a standard method be used to measure the sample's vapor pressure in a constant temperature PVT cell. 24 refs., 33 figs.

Anoxic corrosion and microbial degradation of contact-handled transuranic waste may produce sufficient quantities of gas over a long time period to generate high pressure in the disposal rooms at the Waste Isolation Pilot Plant (WIPP) repository. Dissipation of pressure by outward gas flow will be inhibited by the low permeability of the surrounding rock and by capillary forces that resist gas penetration into this water-saturated rock. Threshold pressure is the gas pressure required to overcome capillary resistance to initial gas penetration and to the development of interconnected gas pathways that would outward gas flow. The primary objectives of this study are to estimate the magnitude of threshold pressure in the bedded salt that surrounds the WIPP repository and to evaluate the role this parameter plays in controlling the outward flow of waste-generated gas. 54 refs., 9 figs., 4 tabs.

The Heat Source/Radioisotopic Thermoelectric Generator shipping container is a Type B packaging design currently under development by Los Alamos National Laboratory. Type B packaging for transporting radioactive material is required to maintain containment and shielding after being exposed to the normal and hypothetical accident environments defined in Title 10 Code of Federal Regulations Part 71. A combination of testing and analysis is used to verify the adequacy of this package design. This report documents the test program portion of the design verification, using several prototype packages. Four types of testing were performed: 30-foot hypothetical accident condition drop tests in three orientations, 40-inch hypothetical accident condition puncture tests in five orientations, a 21 psi external overpressure test, and a normal conditions of transport test consisting of a water spray and a 4 foot drop test. 18 refs., 104 figs., 13 tabs.

This report describes high voltage dc breakdown tests on various PtAu and Au thick film hybrid microcircuits on alumina (Al{sub 2}O{sub 3}). Samples were prepared with current thick film design and manufacturing rules. The purpose was to determine the voltage margins between current design rules and typical applied voltages on real circuits. We also analyzed what happened during a breakdown event. We used a versatile computer-controlled test set to obtain breakdown data. This showed that design conductors 10 mil wide with equal design spaces on alumina and coated with a fired protective glaze (DuPont 9137) had the highest breakdown values (2700 Vdc). Bare design circuits and Au conductor crossover features had a lower breakdown value (1400 to 1600 Vdc). Both these values are well above logic circuit applied voltages ({le}50v). This may account for the excellent field performance obtained to date. Ambient humidity changes to 43% R.H. and voltage rise rates between 3 and 2300 V/sec had little influence on breakdown values ({le}200 Vdc). Voltage breakdown values were little influenced by our two geometries: point-to-line samples which simulated corners and long parallel line samples. Breakdown behaved like a spark in air rather than an arc. Breakdown in glaze went through it to air rather than along the glaze/alumina interface. The spark was found to be similar to lightning in that it consisted of a string of current pulses lasting a total of 1 to 2 seconds. Spark locations were from surface asperities or defects near but not at the point of minimum optically measured separation. Hence, we found that circuits made using current design rules for hybrid microcircuit manufacture are adequate or conservative as regards safe margins against logic voltage dc breakdown to the extent studied here. 13 refs., 19 figs.

Electromagnetic Interference (EMI) problems have resulted in the redesign of the SANDAC V computer case and shielding of its connecting cables. In this report are detailed discussions on the use of computer models and of the tests performed to solve the EMI problems. Included is documentation on the specific changes made to the SANDAC V computer case and the shielding done on the connecting cables. Also documented are the current EMI capabilities relative to MIL Std. 461.

This report represents the first quarterly submittal of data by Sandia National Laboratories (SNL) for the Department Of Energy (DOE) Headquarters Performance Indicator Program. Secretary of Energy Notice (SEN-29-91) directed that a Department-wide uniform systems of Performance Indicators (PIs) for trending and analyzing operational data to help assess and support progress in improving performance and in strengthening line management control of operations relating to environmental, safety, and health activities'' be developed. Trending and analysis of data depicting the performance of facilities is an essential element in creating a culture of continuous improvement,'' where performance gains are maintained and deteriorating environmental, safety, and health conditions are identified early. In addition, good practices that can benefit other DOE operations areas should be identified. The program defines 21 Pi's grouped into four broad areas: (1) personnel safety; (2) operational incidents; (3) environmental releases (normal operations); and (4) management (including waste generation). SNL is required to submit data on 21 PIs for four facilities/reporting elements that were selected by DOE at Albuquerque and Livermore. 31 figs.

In the certification of packages for transport of radioactive material, the issue of slapdown must be addressed. Slapdown is a secondary impact of the body caused by rotational accelerations induced during eccentric primary impact. In this report, several parameters are evaluated that affect slapdown severity of packages for the transport of nuclear material. The nose and tail accelerations in a slapdown event are compared to those experienced by the same cask in a side-drop configuration, in which there is no rotation, for a range of initial impact angles, impact limiter models, and friction coefficients for two existing cask geometries. In some cases, the rotation induced during a shallow-angle impact is sufficient to cause accelerations at the tail during secondary impact to be greater than those at the nose during initial impact. Furthermore, both nose and tail accelerations are often greater than the side-on accelerations. The results described here have been calculated using the code SLAPDOWN, which approximates the impact response of deformable bodies. Finally, SLAPDOWN has been used to estimate the coefficient of friction acting at the nose and tail for one particular cask during one specific slapdown drop test by comparison of results with experimental data. 2 refs., 16 figs., 3 tabs.

Two methods for modeling arbitrary narrow apertures in finite- difference time-domain (FDTD) codes are presented in this paper. The first technique is based on the hybrid thin-slot algorithm (HTSA) which models the aperture physics using an integral equation approach. This method can model slots that are narrow both in width and depth with regard to the FDTD spatial cell, but is restricted to planar apertures. The second method is based on a contour technique that directly modifies the FDTD equations local to the aperture. The contour method is geometrically more flexible than the HTSA, but the depth of the aperture is restricted to the actual FDTD mesh. A technique to incorporate both narrow-aperture algorithms into the FDTD code, TSAR, based on a slot data file'' is presented in this paper. Results for a variety of complex aperture contours are provided, and limitations of the algorithms are discussed.

The results of a Sandia National Laboratories program to design and develop a high-current thermal battery for the Hypersonic Weapons Technology Program are presented. The feasibility of a 200 A, 150 s, 12 Vdc primary battery was demonstrated under ambient conditions. New header feedthrough design concepts were used, and new internal current collectors and internal power leads were considered. The Li(Si)/LiBr-LiCl-LiF/FeS{sub 2} electrochemical system has shown exceptional performance at the high-current operation conditions. A high-rate Zinc/Silver Oxide secondary cell was also evaluated, and the results are presented in this report. These cells exhibited excellent high-rate discharge performance. 5 refs., 19 figs., 8 tabs.

A Performance Assessment Calculational Exercise for 1990 (PACE-90) was coordinated by the Yucca Mountain Site Characterization Project Office for a total-system performance-assessment problem. The primary objectives of the exercise were to develop performance-assessment computational capabilities of the Yucca Mountain Project participates and to aid in identifying critical elements and processes associated with the calculation. The problem defined for PACE-90 was simulation of a ``nominal case`` groundwater flow and transport of a selected group of radionuclides through a portion of Yucca Mountain. Both 1-D and 2-D calculations were run for a modeling period of 100,000 years. The nuclides used, {sup 99}Tc, {sup 135}Cs, {sup 129}I, and {sup 237}Np, were representative of ``classes`` of long-lived nuclides expected to be present in the waste inventory. Movement of the radionuclides was simulated through a detailed hydrostratigraphy developed from Yucca Mountain data specifically for this exercise. The results showed that, for the specified conditions with the conceptual models used in the problem, no radioactive contamination reached the water table, 230 m below the repository. However, due to the unavailability of sufficient site-specific data, the results of this exercise cannot be considered a comprehensive total-system- performance assessment of the Yucca Mountain site as a high-level- waste repository. 46 refs., 94 figs., 19 tabs.

Hydrogen is highly mobile in Si and vitreous SiO₂, and it reacts strongly with dangling bonds residing on Si and O atoms. These interactions have important consequences for metal-oxide- semiconductor structures, with noteworthy effects including the passivation of electrically active defects, mediation of radiation sensitivity, chemical passivation of etched Si surfaces, and still poorly understood effects on epitaxial growth from H-containing media. Despite the significance of these H reactions, fundamental understanding of them has remained seriously deficient; the H bonding energies have been known semiquantitatively at best, and the detailed reaction paths and rate-determining energetics of intermediate states have remained largely speculative. We are addressing these issues through a coordinated program of experiment and theory with the goal of a unified, quantitatively predictive understanding.

A semiconductor laser coupled to an external cavity is investigated using a composite-cavity mode approach. Strong frequency hopping for small cavity length changes is obtained, indicating instability of the laser operation against cavity lengths fluctuations.

Results have been obtained on hydrogen dose, dose rate and substrate temperature dependence for hydrogen-assisted thermal donor formation in Czochralski Si. The study combined ion implantation and hydrogen plasma exposure to inject hydrogen, and infrared absorption and spreading resistance probe measurements to detect the donors. Near surface donor concentrations increase with dose and temperature between 350 and 400°C. The penetration depth for thermal donor formation exhibits a $\sqrt{t}$ dependence, and a thermal activation energy of 1.5 ± 0.2 eV.

Adhesion between diamond films synthesized by a CVD method and tungsten has been investigated by a scratch and pull testing methods. Diamond films have been deposited at temperatures from 1173 to 1323 K with a growth rate ranging from 0.2 to 0.45 μm/hour. The films are highly crystalline and are dominated by (100) faces at low temperatures, changing to (111) at higher temperatures. Grain size and residual stress in the films increases with increasing deposition temperature. X-ray diffraction shows the expected diamond diffraction peaks plus peaks attributed to WC and W₂C. Raman spectroscopy shows a sharp diamond band for all of the films, with a small broad peak, attributed to amorphous carbon. There is no distinct correlation between diamond/amorphous carbon intensity with deposition temperature. Scratch adhesion testing shows the expected failure mode for brittle coatings, but can not be quantified because of severe degradation of the diamond stylus tip. Sebastion pull testing shows that the failure mode of the films correlates with deposition temperature, but specific adhesion strength values do not. Efforts are continuing to correlate adhesion strength with deposition and structural parameters of the diamond films.

Rational interpolation is frequently useful for generating functions which have an extended range over an abbreviated domain of definition. A simple technique for continued fraction interpolating function evaluation can easily be modified to obtain the function's derivative. This is a useful technique for developing numerical solutions for certain stiff partial differential equations. 9 refs., 2 figs.

This 1990 report contains monitoring data from routine radiological and nonradiological environmental surveillance activities. Summaries of significant environmental compliance programs in progress such as National Environmental Policy Act (NEPA) documentation, environmental permits, environmental restoration, and various waste management programs for Sandia National Laboratories in Albuquerque (SNL, Albuquerque) are included. The maximum offsite dose impact was calculated to be 2.0 {times} 10{sup {minus}3} mrem. The total 50-mile population received a collective dose of 0.82 person-rem during 1990 from SNL, Albuquerque, operations. As in the previous year, the 1990 SNL operations had no adverse impact on the general public or on the environment. This report is prepared for the US Department of Energy in compliance with DOE Order 5400.1. 97 refs., 30 figs., 137 tabs.

There is no routine radioactive emission from Sandia National Laboratories, Tonopah Test Range (SNL, TTR). However, based on the types of test activities such as air drops, gun firings, ground- launched rockets, air-launched rockets, and other explosive tests, possibilities exist that small amounts of depleted uranium (DU) (as part of weapon components) may be released to the air or to the ground because of unusual circumstances (failures) during testing. Four major monitoring programs were used in 1990 to assess radiological impact on the public. The EPA Air Surveillance Network (ASN) found that the only gamma ({gamma}) emitting radionuclide on the prefilters was beryllium-7 ({sup 7}Be), a naturally-occurring spallation product formed by the interaction of cosmic radiation with atmospheric oxygen and nitrogen. The weighted average results were consistent with the area background concentrations. The EPA Thermoluminescent Dosimetry (TLD) Network and Pressurized Ion Chamber (PIC) reported normal results. In the EPA Long-Term Hydrological Monitoring Program (LTHMP), analytical results for tritium ({sup 3}H) in well water were reported and were well below DOE-derived concentration guides (DCGs). In the Reynolds Electrical and Engineering Company (REECo) Drinking Water Sampling Program, analytical results for {sup 3}H, gross alpha ({alpha}), beta ({beta}), and {gamma} scan, strontium-90 ({sup 90}Sr) and plutonium-239 ({sup 239}Pu) were within the EPA's primary drinking water standards. 29 refs., 5 figs., 15 tabs.

PC-1D is a software package for personal computers that uses finite-element analysis to solve the fully-coupled two-carrier semiconductor transport equations in one dimension. This program is particularly useful for analyzing the performance of optoelectronic devices such as solar cells, but can be applied to any bipolar device whose carrier flows are primarily one-dimensional. This User's Guide provides the information necessary to install PC-1D, define a problem for solution, solve the problem, and examine the results. Example problems are presented which illustrate these steps. The physical models and numerical methods utilized are presented in detail. This document supports version 3.1 of PC-1D, which incorporates faster numerical algorithms with better convergence properties than previous versions of the program. 51 refs., 17 figs., 5 tabs.

The disappearance of isocyanate groups in 20 lb/ft{sup 3} rigid polyurethane encapsulating foam (44402-20) was monitored by FTIR spectroscopy leading to an activation energy of 4 kcal/mole. The disappearance of isocyanates can be due to either crosslinking reactions or gas production. Attempting to separate these two reaction paths, we measured the gel time and volume change during cure leading to activation energies of 5 and 6 kcal/mole for the crosslinking and foaming mechanisms respectively. 3 refs., 16 figs.

This study examined the feasibility of the Safety Engineering Reactor for Accident Phenomenology (SERAPH), a research reactor with the capability to perform a wide array of safety experiments important in the design of commercial nuclear reactors. The study proceeded in two phases. In Phase 1, the experimental needs were examined and a wide-ranging survey of many fuel/coolant options for the SERAPH driver reactor was done. In Phase 2, the most promising candidates identified in Phase 1 were studied in more detail. A reactor with heavy-water coolant, BeO-PuO{sub 2} fuel matrix, and a standard pin geometry was found to have the required experiment capabilities while using relatively current technology. A reactor with helium coolant, BeO-PuO{sub 2} fuel matrix, and a unique geometrical configuration was found to have significantly higher capabilities but with greater technical risk. 5 refs., 34 figs., 36 tabs.

This report describes the results of high temperature steam testing and submergence testing of 12 different cable products that are representative of typical cables used inside containments of US light water reactors. Both tests were performed after the cables were exposed to simultaneous thermal and radiation aging, followed by exposure to loss-of-coolant accident simulations. The results of the high temperature steam test indicate the approximate thermal failure thresholds for each cable type. The results of submergence test indicate that a number of cable types can withstand submergence at elevated temperature, even after exposure to a loss-of-coolant accident simulation. 4 refs., 6 figs., 9 tabs.

This work documents a comparison of sensitivity and uncertainty analysis techniques that are likely to be used in support of repository performance assessments to determine compliance with the Nuclear Regulatory Commission (NRC) and the Environmental Protection Agency (EPA) regulations for high-level radioactive waste (HLW) repositories. A variety of parameter estimation and sensitivity analysis techniques were applied to a model of the Avra Valley aquifer, Arizona. Two approaches to sensitivity analyses were used, statistical and deterministic; these were applied to evaluate the sensitivity of the ground water travel time to changes in transmissivity. The effect of different boundary conditions on the calculated sensitivity derivatives was also evaluated. Parameter estimates and estimation errors were obtained via geostatistical and inverse techniques. The throughput'' of the kriging techniques suggests that the mean estimates derived from these techniques are frequently off the mark'' or inconsistent with the conceptual model. With no screening of the input parameter estimates for realism, non- conservative travel time estimates were obtained. The differential analysis sensitivity technique is shown to be dependent on the choice of design point, providing only a local measure of the sensitivity. The statistical approach to sensitivity identifies parameters which are both sensitive and uncertain, i.e., it shows when the uncertainty in a model parameter is important. Sensitivity estimates are also shown to be dependent on the choice of boundary conditions used. 92 refs., 55 figs., 13 tabs.

This report describes an architecture for compiling and representing electronic documents in a framework which accommodates knowledge about how the documents are composed, organized, and correlated. A general concept of referenceability is employed. While the concept is relevant to a wide range of application areas, it is described in familiar terms of an electronic document comprised of related textual information and graphics. The concept is applicable to all classes of objects which, together with their references, constitute the electronic document. The documents may themselves contain references to other documents, as well as to constituent object classes such as textual components, figures, footnotes, subject indexes, and the like. The objects and references can be dynamically combined according to a total logical structure representable within a window environment. The framework supports automatic resolution of references and display of related document objects through intercommunicating windows which constitute a relevant user view of a document. 6 refs., 9 figs.

This document describes the NEFTRAN-S computer code and is intended to provide the reader with enough information to use the code. NEFTRAN-S was developed for the United States Environmental Protection Agency for the assessment of ground-water flow and radionuclide transport from radioactive waste disposal in geologic formations. NEFTRAN-S is a successor to the NEFTRAN code. The code was developed in conjunction with NEFTRAN-2, which was developed recently for the United States Nuclear Regulatory Commission. As a result, some of the features contained in NEFTRAN-2 have been included in NEFTRAN-S. In particular, NEFTRAN-S includes an exponential-leach-rate source, decoupled time steps for source and transport, and an option for inputting pore-water velocities. Features unique to NEFTRAN-S include a user-friendly format for use on personal computers and coupling with statistical sampling and analysis using the SUNS software shell. This document was written to provide a comprehensive discussion of the NEFTRAN-S code including its history, the theory, its use and examples of possible applications. Minimal reference to previous documents is intended. 25 refs., 132 figs., 30 tabs.

The default format for the storage of x,y data for use with the UFO code is described. The format assumes that the data stored in a file is a matrix of values; two columns of this matrix are selected to define a function of the form y = f(x). This format is specifically designed to allow for easy importation of data obtained from other sources, or easy entry of data using a text editor, with a minimum of reformatting. This format is flexible and extensible through the use of inline directives stored in the optional header of the file. A special extension of the format implements encoded data which significantly reduces the storage required as compared wth the unencoded form. UFO supports several extensions to the file specification that implement execute-time operations, such as, transformation of the x and/or y values, selection of specific columns of the matrix for association with the x and y values, input of data directly from other formats (e.g., DAMP and PFF), and a simple type of library-structured file format. Several examples of the use of the format are given.

This report documents the findings of an experimental investigation of the effects of thermal aging on the fire damageability of electric cables. Two popular types of nuclear qualified cables were evaluated. For each cable type, both unaged (i.e., new off the reel) and thermally aged samples were exposed to steady-state elevated temperature environments until conductor-to-conductor electrical shorting was observed. Plots of the time to electrical failure versus the exposure temperature were developed and thermal damage thresholds were determined. For one cable type, the thermally aged cables were less vulnerable to thermal damage than were the unaged samples as demonstrated by an increase in the thermal damage threshold for the aged samples, and an extended survival time at exposure temperatures above the damage threshold for aged samples compared to unaged samples. For the second cable, the threshold of thermal damage was lowered somewhat by the aging process, an indication of an increased vulnerability to thermal damage due to aging. However, for the higher temperature exposures, no statistical difference between the damage times for aged and unaged cable samples was noted. For both cable types, the changes in the thermal damage threshold observed were not considered significant in terms of fire risk. 4 refs., 9 figs., 8 tabs.

The thrust of this progress report deals with the significant advances we have made in the past few months toward optimal radiating efficiency and optimal directionality from antenna arrays that fit inside a 5.5 in.-OD tool. The reasons spawning this development effort on antennas are the many uses for underground radar systems that can be built around such high-performance antennas. Targets of interest include large man-made voids, natural voids in strata, fractures zones in hard rock, edges and internal faults in salts domes and glaciers, etc. Recent progress includes observation of the radiation patterns of several dipole arrays which we designed to fit within a 5.5-inch OD borehole tool and to radiate efficiently at wavelengths in the band from 0.4 meter to 2 meters with optimal directionality. Front-to-back ratios of 15 dB are consistently observed in the horizontal plane of these arrays. These antennas are observed to radiate with high efficiencies, less than 1 dB loss, into air at 1.3 meter wavelength. 18 figs.

This report describes the finite difference computer code ZEPHYR3D, which is designed to solve three-dimensional, transient incompressible flow problems. ZEPHYR3D includes an energy equation that allows coupled thermal/fluid problems to be solved with the limits of the Boussinesq approximation. It also includes an implementation of the Smagorinsky subgrid scale turbulence model, which allows ZEPHYR3D to perform large eddy simulation of turbulent flows. This report includes the mathematical and numerical basis for ZEPHYR3D, a user's guide, and several example/benchmark problems. These problems include flow over a backward-facing step, free convection in an enclosure, and the collapse of a mixed region in a stratified environment. 22 refs., 32 figs., 2 tabs.

Early in 1990, J. A. Wilder, Supervisor of Sandia National Laboratories (SNLA), Division 2565 requested that a meeting of the scientists and engineers responsible for developing and producing switch tubes be set up to discuss in a semi-formal way the science and technology of switch tubes. Programmatic and administrative issues were specifically exempted from the discussions. L. Beavis, Division 7471, SNL and A. Shuman, EG G, Salem were made responsible for organizing a program including the materials and processes of switch tubes. The purpose of the Switch Tube Advanced Technology meeting was to allow personnel from Allied Signal Kansas City Division (AS/KCD); EG G, Salem and Sandia National Laboratories (SNL) to discuss a variety of issues involved in the development and production of switch tubes. It was intended that the formal and informal discussions would allow a better understanding of the production problems by material and process engineers and of the materials and processes by production engineers. This program consisted of formal presentations on May 23 and informal discussions on May 24. The topics chosen for formal presentation were suggested by the people of AS/KCD, EG G, Salem, and SNL involved with the design, development and production of switch tubes. The topics selected were generic. They were not directed to any specific switch tube but rather to all switch tubes in production and development. This document includes summaries of the material presented at the formal presentation on May 23.

The diffraction patterns produced by passing a laser beam through two different types of flowing gases are calculated. The first type of flow consists of periodic lines of gas flowing transverse to the beam's propagation. The second flow is turbulent. The measurable parameters in the diffraction patterns are derived and related to the gas temperature, pressure, velocity, and (in the case of the turbulent flow) to the flow's structure constant. A discussion on using the photorefractive effect to study turbulent flows is also given. In the latter case a method that relates the flow's structure constant to the decay time of the photorefractive crystal is given. 24 refs., 11 figs.

NEFTRAN-S was developed by Sandia National Laboratories for the United States Environmental Protection Agency as part of a program providing technical support for re-promulgation of the standard 40 CFR 191. The code is intended to provide realistic estimates of releases to the environment that could result from disposal of radioactive waste in geologic subsurfaces. One of the geologic environments that will be considered by the EPA in their analyses is unsaturated tuff. The information given in this report is intended to provide a conceptual model for the NEFTRAN-S code for calculations involving a generic site in unsaturated tuff. Information about the phenomena expected to dominate transport and methods for modeling transport in an unsaturated medium are presented. NEFTRAN-S calculations using this conceptual model are compared to TOSPAC calculations for three possible infiltration rates. TOSPAC is the code currently used in performance assessment for an unsaturated tuff site at Yucca Mountain in Nevada. 14 refs., 21 figs., 22 tabs.

The prediction of the chemical alteration of cementitious sealing materials and other cementitious components such as liners in the tuffaceous environment of Yucca Mountain is an essential element in understanding the longevity of these materials. This study uses a chemical equilibrium model to obtain information about the chemical reaction of ground water with concretes. Because concretes, cements, and grouts are metastable assemblages, it is expected that these materials will dissolve, cause secondary precipitations and react with the environment. These reactions will alter the porosity and hydraulic conductivity of the concretes. While the importance of these chemical and conductivity changes has not been completely assessed, this study provides insight into the importance of this chemical alteration.

Radiation measurement have been used for many years to aid in the characterization, handling, and processing of spent nuclear fuel. Applications have included radiation protection, international safeguards, fissile content estimation for reprocessing, and verification of records and calculations. The application of radiation measurements to support the identification of spent fuel assemblies for loading into burnup credit'' transport casks is of interest in the cask development program. A possible alternative to measurements is to use the administrative controls and operational procedures that have been used at reactor sites that make use of burnup credit for spent fuel storage. Experience at such sites needs to be carefully analyzed for its applicability to the misloading and misidentification probabilities. Since there are over 40,000 spent fuel assemblies stored at more than one hundred locations in the US, it is important to determine carefully the necessity for and applicability of any measurement requirement. It is imperative that any measurement system selected be as simple, inexpensive, quick, and non-intrusive as possible. In this report we will consider the information available from measurements of spent fuel that has cooled for more than ten years and examine the possible application of existing instrumentation to verifying the loading of burnup credit casks.

Sandia National Laboratories is conducting long-term aging research on representative samples of nuclear power plant Class 1E cables to determine the suitability of these cables for extended life (beyond the 40-year design basis) and to assess various cable condition monitoring techniques for predicting remaining cable life. This paper provides some results of mechanical measurements that were performed on cross-linked polyolefin (XLPO) cables and cable materials aged at relatively mild, simultaneous thermal and radiation exposure conditions for period of up to nine months. The mechanical measurements discussed in this paper include tensile strength, ultimate elongation, hardness, and compressive modulus. The modulus measurements were performed using an indenter developed at Franklin Research Center under EPRI sponsorship.

Sandia National Laboratories, Albuquerque, manages the Utility Battery Exploratory Technology Development Program, which is sponsored by the US Department of Energy's Office of Energy Management. In this capacity, Sandia is responsible for the engineering analyses and development of advanced rechargeable batteries for stationary energy storage applications. This report details the technical achievements realized during fiscal year 1990. 82 figs., 40 tabs.

This document presents the quality assurance (QA) philosophy and procedures for software used by the Performance Assessment Division of the Nuclear Waste Technology Department (NWTD) of Sandia National Laboratories, which directly supports the Waste Isolation Pilot Plant (WIPP). Software procedures described herein will be incorporated into the general Performance Assessment Quality Assurance Procedures (QAP 2-2) and will apply to all Sandia and Sandia contractor activities related to Performance Assessment (except where the contractor has its own NWTD-approved QA procedures). This report presented the philosophy behind the QA procedures, provides the standards adopted for Performance Assessment software, discusses the implementation of these standards, and summarizes the software executive package, CAMCON, which aids in implementing the standards. 24 refs., 6 figs., 5 tabs.

Our charged particle simulation models a relativistic electron beam for which the field solution is local and thus requires no grid. We have implemented the simulation on a CRAY and on two parallel machines, a nCUBE 2 and Connection Machine. We present implementation details and contrast the approaches necessary for the three architectures. On the parallel machines a dynamic load-balancing problem arises because the beam grows uniformly in one dimension from a few hundred to hundreds of thousands of particles as the simulation progresses. We discuss a folded Gray-code mapping of the processors to the length scale of the simulation that expands (or shrinks) as the beam changes length so as to minimize inter-processor communication. This improves the efficiency of the nCUBE version of the simulation which runs at 10x the speed of the vectorized CRAY version.

Surry was used as a representative dry containment plant for the evaluation of possible ways that containment performance could be improved. Sensitivity studies using the NUREG-1150 models and methodologies were used to estimate the reduction of risk potentials resulting from bypass scrubbing and DCH partial depressurization. These studies showed that the greatest reduction of risk occurs when bypass releases are mitigated by scrubbing or prevented. High-pressure DCH are also important. The CONTAIN code was used to estimate reduction in peak containment pressure resulting from mitigation actions including venting, partial depressurization and {approximately}3 bar with igniters. Limited studies of the benefits of venting and inerting were made, but additional investigations are needed to complete this area of investigation. A brief discussion regarding concepts to mitigate the consequences of bypass is presented. CONTAIN-code calculations were performed to investigate the possible overpressurization of the containment for the station blackout scenario. 30 refs., 24 figs., 17 tabs.

Analytical equations for explosively accelerated flyer plates are used to generate graphical solutions to flyer problems. Given the problem geometrical configuration, explosive weight, flyer weight, tamping weight and Gurney velocity, the graphical representation of the calculated data allows for a fast approximation of the final or maximum flyer velocity. The graphical solution for flyer velocity is particularly useful when a computer is not available. The graphical analysis scheme can be used with any explosive, tamper and flyer materials. Analytical data are presented for grazing, spherical, cylindrical, open, symmetric and asymmetric sandwich explosive configurations. 13 refs., 7 figs., 4 tabs.

Al with additions of Cu is commonly used as the conductor metallizations for integrated circuits (ICs). As the packing density of ICs increases, interconnect lines are required to carry ever higher current densities. Consequently, reliability due to electromigration failure becomes an increasing concern. Cu has been found to increase the lifetimes of these conductors, but the mechanism by which electromigration is improved is not yet fully understood. In order to evaluate certain theories of electromigration it is necessary to have a detailed description of the Cu distribution in the Al microstructure, with emphasis on the distribution of Cu at the grain boundaries. In this study analytical electron microscopy (AEM) has been used to characterize grain boundary regions in an Al-2 wt.% Cu thin film metallization on Si after a variety of thermal treatments. The results of this study indicate that the Cu distribution is dependent on the thermal annealing conditions. At temperatures near the θ phase (CuAl₂) solvus, the Cu distribution may be modelled by the collector plate mechanism, in which the grain boundary is depleted in Cu relative to the matrix. At lower temperatures, Cu enrichment of the boundaries occurs, perhaps as a precursor to second phase formation. Natural cooling from the single phase field produces only grain boundary depletion of Cu consistent with the collector-plate mechanism. The kinetic details of the elemental segregation behavior derived from this study can be used to describe microstructural evolution in actual interconnect alloys.

A 70/30 wt% salt/bentonite mixture is shown to be preferable to pure crushed salt as backfill for disposal rooms in the Waste Isolation Pilot Plant (WIPP). This report discusses several selection criteria used to arrive at this conclusion: the need for low permeability and porosity after closure, chemical stability with the surroundings, adequate strength to avoid shear erosion from human intrusion, ease of emplacement, and sorption potential for brine and radionuclides. Both salt and salt/bentonite are expected to consolidate to a final state of impermeability (i.e., {le} 10{sup {minus}18}m{sup 2}) adequate for satisfying federal nuclear regulations. Any advantage of the salt/bentonite mixture is dependent upon bentonite's potential for sorbing brine and radionuclides. Estimates suggest that bentonite's sorption potential for water in brine is much less than for pure water. While no credit is presently taken for brine sorption in salt/bentonite backfill, the possibility that some amount of inflowing brine would be chemically bound is considered likely. Bentonite may also sorb much of the plutonium, americium, and neptunium within the disposal room inventory. Sorption would be effective only if a major portion of the backfill is in contact with radioactive brine. Brine flow from the waste out through highly localized channels in the backfill would negate sorption effectiveness. Although the sorption potentials of bentonite for both brine and radionuclides are not ideal, they are distinctly beneficial. Furthermore, no detrimental aspects of adding bentonite to the salt as a backfill have been identified. These two observations are the major reasons for selecting salt/bentonite as a backfill within the WIPP. 39 refs., 16 figs., 6 tabs.

Microporous polymers are useful for applications as diverse as separation membranes and physical supports for chemically active species. One of the most important preparation methods employs thermal demixing of solution. Differences in the morphology of thermally demixed 2 wt% solutions of PAN in maleic anhydride cannot be explained by existing models, which are based on phase diagrams. An explanation based on degradation of the polymer is not supported by GPC, NMR, or FTIR experiments. We speculate that the physical structure of the polymer in solution, involving either intramolecular dimensions or intermolecular aggregation, has an important effect on the morphology.

A new technique for tunnel detection and location has recently been theoretically modeled and experimentally demonstrated. The objective of this research is to develop a general method for remotely detecting the presence of unauthorized tunneling activities using one or more boreholes and a surface source. A line current or dipole-dipole array, positioned on or near the surface of the earth, is used as the TE current source. Subsurface electric and magnetic field measurements are made in a borehole that is situated near a suspected tunnel location. The presence of a tunnel causes subsurface scattering of the field components created by the source. Both the electric and magnetic field strength and phase data is perturbed by the presence of a nearby tunnel. The scattered fields are observed on both sides of the tunnel relative to the source position. This paper will describe the development electromagnetic scattering models using a buried cylinder to represent a tunnel. A homogeneous whole-space model will be used. 5 refs., 20 figs.

Eight samples of 4.5 in. steel oil well drill pipe which had perforated or fractured in use were analyzed to determine the reasons for failure. These pipe sections were used for drilling in the Permian Basin fields of southeastern New Mexico and western Texas. Six of the eight samples failed by a common mechanism: stress corrosion cracks initiated at the insides of the pipes at the bottoms of large corrosion blisters which formed under a plastic protective layer. Stress corrosion cracking (SCC) was driven by a differential oxygen concentration cell between the drilling fluid (high oxygen) and the bottom of the blisters (low oxygen). The stress corrosion process occurs by a film rupture-plastic slip-electrochemical dissolution mechanism. Thus crack propagation rates may be altered by chemical modification of drilling fluids. Additional crack extension occurred by fatigue in some samples; the extent of fatigue cracking apparently was determined by the later cyclic history of the pipe. Treatment of the drilling fluids to lower the oxygen concentration and thus the driving force for SCC has been shown to decrease drill pipe loss by perforation in limited drilling to date. 16 refs., 8 figs.