Publications

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.

Accomodation of lattice mismatch is investigated for the case of large (ε{lunate}>0.02) mismatch. In particular, the regime where the separation D between misfit dislocations is much less than the strained layer thickness h is considered here. The conventional Matthews-Blakeslee mechanism for creation of misfit dislocations is found to be inadequate for the case of large lattice relaxation owing to interactions amongst the misfit dislocations at the interface. According to St. Venant's principle, the stress fields of the dislocation network are screened beyond a distance D from the dislocation cores. This observation has several consequences, including large densities of threading dislocations and the "melting" of moderately relaxed heterointerfaces at conventional semiconductor growth temperatures. A number of experimental observations may be explained via these models. © 1991.

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.

Large-scale numerical simulations of turbulent flow past bare and appended submarine hulls have been completed with FIDAP versions 4.5 and 5.0. A standard k-ε turbulence model was employed to resolve the near-body flow field for all numerical calculations. Results from these simulations (profile plots and wake surveys of velocity, pressure and turbulent kinetic energy -- hull pressures and shear stresses -- total drag) are compared with data from dynamically similar experiments. The Reynolds number, based upon model length, for both simulation and experiment was 1.2 x 10⁷. Agreement between untuned numerical predictions and experimental data is remarkably close for several model geometries. In other cases, quantitative differences are attributed to the choice of turbulence model and the numerical implementation of boundary conditions.

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.

Reflux solar receivers for dish-Stirling electric power generation systems are currently being investigated by several companies and laboratories. In support of these efforts, the AEETES thermal performance numerical model has been developed to predict thermal performance of pool-boiler and heat-pipe reflux receivers. The formulation of the AEETES numerical model, which is applicable to axisymmetric geometries with asymmetric incident fluxes, is presented in detail. Thermal efficiency predictions agree to within 4.1% with test data from on-sun tests of a pool-boiler reflux receiver. Predicted absorber and sidewall temperatures agree with thermocouple data to within 3.3.% and 7.3%, respectively. The importance of accounting for the asymmetric incident fluxes is demonstrated in comparisons with predictions using azimuthally averaged variables. The predicted receiver heat losses are characterized in terms of convective, solar and infrared radiative, and conductive heat transfer mechanisms. 27 refs., 9 figs., 4 tabs.

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 ~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.

Difficulties in the accurate heat transfer computation of high speed, blunt body flows have been encountered by numerous researchers. The primary reason for these difficulties has been shown to be the grid dependency of the wall flux quantities. Obviously, the accuracy of the computed heat fluxes will, to a certain extent, depend on the particular numerical scheme employed. This article will be limited to the investigation of the flux vector splitting technique. An attempt has been made to develop procedures which will provide guidelines for selecting appropriate grid systems and, in particular, the grid line distribution near the surface for accurate heat transfer computations. The results have clearly shown the dependency of the heat flux quantities on the grid system. In addition, it is shown that changes in flow Mach number and/or Reynolds number may require further refinement of the grid system.

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.

We present an algorithm for the QR factorization of a dense matrix without column pivoting on a hypercube multiprocessor. The algorithm combines the optimal numerical efficiency of Householder reflections with the excellent communication properties of the torus wrap mapping. Analytical results indicate that the communication cost for this algorithm is less than that for other common approaches. Numerical results on an nCUBE 2 confirm the efficiency of our technique. 23 refs., 5 figs., 1 tab.

This memorandum is a synopsis of the description and operation of the equipment used, and the events occurring during the calibration of an accelerometer on the 1000 G centrifuge. 2 refs., 1 tab.

The objective of this study was to perform a systematic sampling of the intergranular brines that slowly weep'' from four of the main stratigraphic units exposed in the WIPP. This information was added to the data base on brine compositions used in performance assessment and also employed in characterizing Salado Formation hydrology at the repository horizon. Concentrations of Na, K, Mg, Ca, Cl, SO₄, and Br were all highly variable. It was also established that this variability reflects neither post-excavation evaporation nor imprecision in the analytical techniques. Compositional variability on the length scale of a few tens of centimeters is as large as that found over several hundreds of meters. Stratigraphy did not appear to exert any control over weep brine compositions. Programmatically relevant applications of these results are: (1) a valid performance assessment must consider the possibility of a wide range of brines, rather than carry out evaluations using a single best'' average brine, and (2) the Salado appears not to function as a continuous aquifer since brines originating millions of years ago have failed to homogenize though separated by only short distances.

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.

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.

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.

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.

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, α, 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 αL $\ll$ 1, for which absorption by capillary forces is dominant over gravity-induced flow. Conversely, the distribution becomes finger-like along the vertical when αL $\gg$ 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 αD is less than about 4; infiltration rates obtained when the water table depth is semi-infinite are of sufficient accuracy for greater values of αD. 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.

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.

This report discusses the cycloaliphatic epoxide that is UV cured to create protective coatings. Mechanical and electrical properties are briefly discussed.

Sandia National Laboratories is currently assessing whether the Waste Isolation Pilot Plant (WIPP) complies with the Environmental Protection Agency's Environmental Standards for the Management and Disposal of Spent Nuclear Fuel, High-Level, and Transuranic Radioactive Wastes. Assessing compliance of a geologic repository requires the use of many different types of computer modeling programs. For this task, Sandia is developing a controller, CAMCON (Compliance Assessment Methodology CONtroller), which is a software package consisting of a suite of procedural files that control the flow of data between a computational data base and various modeling programs. CAMCON prompts the analyst for specifics about modeling needs, such as code name(s) and number of runs, thus providing a flexible, yet semi-automated framework in which analysts can select the code(s) best suited for a particular problem. CAMCON also incorporates quality assurance features.

Melt-grown crystals in the Tl-Ca-Ba-Cu-O system with the same structure type can have substantial differences in the superconducting transition, both in width and onset temperature. These differences are attributed to stoichiometry variations arising from cation site substitution. Magnetization and electrical resistivity data are presented which emphasize the extreme sensitivity of the superconductivity to the exact stoichiometry in this system. High quality single crystals exhibit large flux creep due to a weak pinning potential for magnetic flux lines. Flux pinning and thus the critical current density are shown to be significantly enhanced by irradiation with high-energy protons or neutrons. © 1991.

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.

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.

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.

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.

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.

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.

Tests have been conducted on bench-scale heat-pipe solar receivers to explore methods of constructing wicks. The primary objective was to develop a wick structure that was easy to fabricate and was capable of transporting liquid sodium over long distances against hydrostatic and frictional pressure drops. One of the wicks tested in this program was able to lift sodium 45 cm by capillary pumping alone to cool a 3-cm×10-cm area subjected to an average flux of 50 W/cm².

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.

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.

Short communication.

Short communication.

The electron photo-excitation from the K- state and its subsequent trapping by K+ state is probably at the origin of the silicon dangling bonds (K0) formation during broad-band UV illumination of the N-rich amorphous silicon nitride films. Because the photo-excited electron will move towards the metal electrode the positive charge is expected to accumulate near the nitride-silicon interface with illumination time. Our data also suggest that the N-H group may be at the origin of the nitrogen dangling bonds creation in N-rich films. © 1991 Elsevier Science Publishers B.V. All rights reserved.

Engineers invest several years becoming skilled in the many disciplines necessary to effectively carry out analysis, design and development. This typically includes math, physics, computer science, and special study in their core area of expertise. However, once promoted into management, engineers use less and less of these hard-earned technical skills and find themselves operating in nontechnical arenas in which they have little or no formal training. (The formal training that they do get is often through company-sponsored courses, lacking both the rigor and cohesiveness that they have grown accustomed to in their engineering curriculum.) Often, what they are exposed to are continually varying management doctrines that resemble the flavor of the month, each laying claim to the true secrets of motivation, productivity, and organizational competitiveness. Under such circumstances, it is difficult for the neophyte manager to sort out fact from fancy, and help from hype. It therefore would be helpful to put such theories in perspective and present them in a form most easily digested by technical managers, i.e., from an analytical point of view. This paper attempts to do just that. There are many factors that influence a manager's career progression. One of the most rational factors is how the manager's actions affect the productivity of his or her group. This paper focuses on principles and techniques that a manager can, and should, employ to improve group productivity and enhance his or her opportunities for further advancement.

A hydraulic fracture stimulation conducted during 1983-1984 in non-marine, deltaic, Mesaverde strata at a depth of 7100 ft (2164 m) was cored in a deviated well in 1990. The observed fracture consists of two fracture intervals, both containing multiple fracture strands (30 and 8, respectively). While the core had separated across many of the fracture strands during coring, the rock remained intact across 20 of the strands, preserving materials within the fractures. Nine of the remaining intact strands were split open, revealing abundant gel residue on the surfaces of every fracture examined. Of 7 strands associated with major bedding planes, 4 displayed offsets of 1-3 mm at the planes and 3 strands had their growth terminated at the planes, showing the importance of bedding (petrophysical heterogeneities) on fracture propagation. Implications of all these findings for hydraulic fracture design and analysis are also addressed.

The Space Exploration Initiative (SEI) seeks to reestablish a U. S. program of manned and unmanned space exploration. The President has called for a program which includes a space station element, a manned habitation of the moon, and a human exploration of Mars. The NASA Synthesis Group has developed four significantly different architectures for the SEI program. One key element of a space exploration effort is the power required to support the missions. The Power Specialty Team of the Synthesis Group was tasked with assessing and evaluating the power requirements and candidate power technologies for such missions. Inputs to the effort came from existing NASA studies as well as other government agency inputs such as those from DOD and DOE. In addition, there were industry and university briefings and results of solicitations from the AIAA and the general public as a part of the NASA outreach effort. Because of the variety of power needs in the SEI program, there will be a need for multiple power system technologies including solar, nuclear and electrochemical. Due to the high rocket masses required to propel payloads to the moon and beyond to Mars, there is great emphasis placed on the need for high power density and high energy density systems. Power system technology development work is needed and results will determine the ultimate technology selections.

Shockwave techniques have been used for decades to study the dynamic states of matter in temperature and pressure regimes inaccessible by other methods. These techniques have been employed in a wide variety of scientific, military, and commercial applications. A principal scientific objective has been to determine high-pressure equations of state (EOS) to ultra-high pressures; pressures of tens of Mbar have been reported for several materials. Most recently, these methods have been used for studies of thermophysical properties under shock compression, including phase transition kinetics, and mechanical properties, such as the high-pressure yield strength. In this paper, a brief discussion of recent developments in high velocity launchers is given. Advances in techniques for subjecting materials to a wide range of loading conditions is presented, including selected illustrations of shockwave measurements to Mbar pressures. 54 refs.

The modern investigation of the thermochemical behavior of salt started in the mid-1930's and, for what appears to be a very narrow discipline, salt mechanics'' has acquired considerable technical depth and sophistication. The last three decades have been especially productive in constitutive model development and laboratory investigations of time-dependent creep behavior. This has been largely due to anticipated use of domal or bedded salt deposits as sites for radioactive waste repositories and to expanded need for hydrocarbon and feedstock storage caverns. Salt is an interesting material, in that it is metal like''; and, therefore, constitutive modeling can draw upon a large body of metal deformation information to arrive at appropriate models of behavior. Testing apparatus and methods have centered on either uniaxial or triaxial compression to obtain steady state and transient creep responses. Flow and fracture potentials have been defined. Validation attempts of the models against field data, although limited, have proved promising. 27 refs.

Typical aerospace joints lead to apertures which are very narrow and thick. We develop a systematic analytical treatment of this type of aperture (precise conditions of validity given in the text), although the results are also applicable to apertures on a thin conducting body. An antenna integral equation with an equivalent antenna radius is used to describe the voltage across a narrow and thick aperture in a perfectly conducting plane. The result shows the voltage across the aperture has very high Q (quality-factor) resonances, because the equivalent radius is exponentially small. Transmitted power also exhibits similar behavior. When metallic and gasket losses are included, a nonlocal antenna model together with a local transmission line model is used to describe the voltage across the aperture. Good metallic walls, such as aluminum, are found to significantly reduce the penetration of an aperture of typical dimensions. Gaskets with relatively small loss tangents also result in significant penetration reductions. A simple transmission line with uniform loading is used to approximate the governing equation described in. In the lossless limit and for moderate fatness parameter this simple transmission line model is comparable in accuracy to King's three-term theory. The loading of the bolts or hinges is demonstrated to act in many cases as a short. Finally, the low frequency penetration for a narrow slot aperture of arbitrary depth is characterized by the equivalent polarizabilities (dominating longitudinal component) as a function of the ratio of the depth to the width and ratio of the length to the width. A general relationship is shown to exist between the equivalent radius and the transverse line dipole moments of a slot aperture with depth. The longitudinal equivalent polarizabilities of antennas and slot apertures are used to derive a coupling energy bound for a step function EMP. 9 refs., 8 figs.

Recent reevaluation of the neutron displacement damage function for silicon qualifies it as a sensor for spectra determinations. This development is especially useful in the critical energy region from 0.2 to 2.0 MeV where, in the absence of fission foils, there is a shortage of response functions needed to define spectra satisfactorily. This paper describes how silicon bipolar devices can be used to improve neutron spectra determinations and therefore to better predict the displacement damage induced in devices. © 1991 IEEE

Gas conductivities of narrow natural fractures in sandstone and chalk were measured under varying stress and pore pressure conditions and showed a decrease in conductivity with increasing net stress. Natural fractures in mudstones exhibited continuously decreasing conductivity upon application of stress, so that correlatable conductivity data could not be obtained. Effective-stress-law behavior for the sandstone and chalk fractures were examined, giving α values in the range of 0.8-1.06, where α is the parameter in the effective-stress law, σ - αP. The value of α for the fracture in chalk was nearly constant, but the values for the fracture in sandstone tended to decrease with increasing stress. Transition Reynold's numbers and turbulence factors for flow through the chalk and sandstone fractures were determined, yielding turbulence factors ranging from 6.0-20×106 ft-1 (2.0-6.6×10-5 cm-1) for differently stressed fractures. The entire flow behavior of these natural fractures, including conductivity, effective-stress law, and turbulence, is controlled by stress and pore pressure. As a result, pressure depletion during production will significantly change the productivity of a reservoir with similar natural fractures.

This report is an overview of advanced nonvolatile memory technologies. The memory technologies discussed are: floating gate nonvolatile memory technologies; SNOS nonvolatile technology; ferroelectric technology; and thin film magnetic memories.

We present a method to conservatively estimate MOS hardness in space that shares the same technical basis as MIL-STD 883C, Test Method 1019.4, but permits greater latitude in part selection for low-dose space systems. Cobalt-60 irradiation at 50–300 rad(Si)/s followed by 25°C anneal is shown to provide an effective test of oxide-charge related failures at low dose rates that is considerably less conservative than Method 1019.4. For MOS devices with gate oxides thinner than 100 nm, we show that an elevated temperature “rebound test” generally is not required for systems with total dose requirements less than 5 krad(Si). For thicker gate oxides and/or higher-dose system requirements, rebound testing per Method 1019.4 generally is required to ensure that devices do not fail in space due to interface-trap effects. © 1991 IEEE

Changes in brine and gas permeability of rock salt as a result of nearby excavation (mine-by) have been measured from the underground workings of the WIPP facility. Prior to the mine-by, the formation responds as a porous medium with a very low brine permeability, a significant pore (brine) pressure and no measurable gas permeability. The mine-by excavation creates a dilated, partially saturated zone in the immediate vicinity of the excavation with an increased permeability to brine and a measurable permeability to gas. The changes in hydrologic properties are discussed in the context of pore structure changes.

For several years Phillips Petroleum Company has been waterflooding portions of the Ekofisk Field reservoir for purposes of enhanced oil recovery. Boreholes drilled in waterflooded portions of the reservoir have encountered poor core recoveries and highly fractured rock (poor core recoveries and highly fractured zones were not uncommon in the Ekofisk reservoir before waterflooding, however). Results of laboratory compression tests designed to simulate production-related compaction and subsequent waterflooding indicate that injection pressures currently used to inject seawater into the reservoir are high enough to induce shear failure in high porosity reservoir chalks. A model of chalk deformation explains brittle failure of chalk that has been subjected to stresses well in excess of yield stress.

The Sandia National Laboratories Pre-Tiger Team Self-Assessment Report contains an introduction that describes the three sites in Albuquerque, New Mexico, Kauai, Hawaii, and Tonopah, Nevada, and the activities associated therewith. The self-assessment was performed October 1990 through December 1990. The paper discusses key findings and root causes associated with problem areas; environmental protection assessment with respect to the Clean Air Act, Clean Water Act, Comprehensive Environmental Response, Compensation, and Liability Act and the Superfund amendments, Resource Conservation and Recovery Act; and other regulatory documents; safety and health assessment with respect to organization administration, quality assurance, maintenance, training, emergency preparedness, nuclear criticality safety, security/safety interface, transportation, radiation protection, occupational safety, and associated regulations; and management practices assessment. 5 figs. (MHB)

Large two- and three-dimensional simulations of shock wave physics problems constitute a major expense in ongoing research efforts at Sandia National Laboratories. Massively parallel computing may provide a solution. A simplified version of the production hydrocode CTH, in current use at Sandia National Laboratories, has been successfully developed for the Connection Machine. The parallel version, named PCTH, solves problems in multi-fluid shock wave physics. The development of the Connection Machine code is described and initial performance statistics are presented. These are compared with similar results for the CRAY Y-MP and nCUBE2. 7 refs., 3 figs., 1 tab.

A Low Altitude High Speed Cargo (LAHSC) parachute is being developed for deployment at velocities up to 250 knots at 300 ft altitude. The LAHSC parachute will decelerate and turnover a load to a 40 to 60 ft/sec vertical velocity at first vertical at approximately 30 ft AGL. The acceleration limit is 5 g's. Main chute cargo extraction will be necessary. A single parachute will be utilized for a 7500 lb load, and clusters will be used for larger loads. The 64-gore, 70-ft-dia parachute has a ring-slot/solid construction with a flare at the skirt to aid the inflation. This paper describes the parachute, the design process and testing to date. Model parachutes have been tested in wind tunnels and in free flight. A single full-scale parachute has been tested at low speeds with conventional load extraction, and with a vertical trajectory at deployment. 5 refs., 18 figs., 3 tabs.

High-speed water-entry is a very complex, dynamic process. As a first attempt at modeling the process, a numerical solution was developed at Sandia National Laboratories for predicting the forces and moments acting on a body with a steady supercavity, that is, a cavity which extends beyond the base of the body. The solution is limited to supercavities on slender, axisymmetric bodies at small angles of attack. Limited data were available with which to benchmark the axial force predictions at zero angle of attack. Even less data were available with which to benchmark the pitching moment and normal force predictions at nonzero angles of attack. A water tunnel test was conducted to obtain force and moment data on a slender shape. This test produced limited data because of waterproofing problems with the balance. A new balance was designed and a second water tunnel test was conducted at Tracor Hydronautics, Inc. This paper describes the numerical solution, the experimental equipment and test procedures, and the results of the second test. 8 refs., 11 figs.

Path planning among movable obstacles is a practical problem that is in need of a solution. An efficient heuristic algorithm is presented that uses a generate-and-test paradigm: a good candidate path is hypothesized by a global planner and subsequently verified by a local planner. In the process of formalizing the problem, a technique for modeling object interactions through contact is presented. The algorithm has been tested on a variety of examples, and was able to generate solutions within 10 s on a 17-MIPS Sun Sparc workstation.

A high-resolution capacitive image sensing technique for measuring edge and surface profiles during manufacturing processes has been invented. A prototype device utilizing this technique consists of two 500-μm-diameter electrodes fabricated on a printed circuit board with a 250-μm gap between them. As the device is mechanically scanned over the workpiece, the spatial variations in the edge or surface to be measured interfere with an electric field imposed between the electrodes, altering the mutual capacitance. The sensor functions as a near-field proximity sensor producing range images of surface imperfections. This sensor has been used in applications requiring a preview image of burns on the edge of a machined part and other processes requiring an inspection image after automated deburring operations.

A series of haptic exploratory procedures (EPs) implemented for a multifingered, articulated, sensate robot hand is discussed. These EPs are designed to extract specific tactile and kinesthetic information from an object via their purposive invocation by an intelligent robotic system. Taken together, they form an active robotic touch perception system. This system utilizes a PUMA 560 robot arm, a JPL/Stanford robot hand with joint torque sensing in the fingers, a wrist force/torque sensor, and a 256-element spatially resolved fingertip tactile array. The EPs are described, and experimental results are given.

An analysis is made of the experimental results of a minimum-time trajectory control scheme for a two-link flexible robot. An offline optimization routine determines a minimum-time, straight-line tip trajectory which stays within the torque constraints of the motors and ends with no vibrational transients. An efficient finite-element model is used in the optimization to approximate the flexible arm dynamics. The control strategy described is used to determine the feedback gains for the position, velocity, and strain gage signals from a quadratic cost criterion based on the finite-element model linearized about the straight-line tip trajectory. These feedback signals are added to the modeled torque values obtained from the optimization routine and used to control the robot arm actuators. The results indicate that this combination of model-based and error-driven control strategies achieves a closer tracking of the desired trajectory and a better handling of modeling errors than either strategy alone.