This study investigates the high frequency response of Faraday effect optical fiber current sensors that are bandwidth-limited by the transit time of the light in the fiber. Mathematical models were developed for several configurations of planar (collocated turns) and travelling wave (helical turns) singlemode fiber sensor coils, and experimental measurements verified the model predictions. High frequency operation above 500 MHz, with good sensitivity, was demonstrated for several current sensors; this frequency region was not previously considered accessible by fiber devices. Planar fiber coils in three configurations were investigated: circular cross section with the conductor centered coaxially; circular cross section with the conductor noncentered; and noncircular cross section with arbitrary location of the conductor. The helical travelling wave fiber coils were immersed in the dielectric of a coaxial transmission line to improve velocity phase matching between the field and light. Three liquids (propanol, methanol, and water) and air were used as transmission line dielectric. Complete models, which must account for liquid dispersion and waveguide dispersion from the multilayer dielectric in the transmission line, were developed to describe the Faraday response of the travelling wave sensors. Other travelling wave current sensors with potentially greater Faraday sensitivity, wider bandwidth and smaller size are investigated using the theoretical models developed for the singlemode fibers coils.
The U.S. Department of Energy (DOE) is responsible for disposing of a variety of radioactive and mixed wastes, some of which are considered special-case waste because they do not currently have a clear disposal option. It may be possible to dispose of some of the DOE`s special-case waste using greater confinement disposal techniques at the Nevada Test Site (NTS). The DOE asked Sandia National Laboratories to investigate this possibility by performing system configuration analyses. The first step in performing system configuration analyses is to estimate the characteristics of special-case waste that might be destined for disposal at the NTS. The objective of this report is to characterize this special-case waste based upon information available in the literature. No waste was sampled and analyzed specifically for this report. The waste compositions given are not highly detailed, consisting of grains and curies of specific radionuclides per cubic meter. However, such vague waste characterization is adequate for the purposes of the system configuration task. In some previous work done on this subject, Kudera et al. [1990] identified nine categories of special-case radioactive waste and estimated volumes and activities for these categories. It would have been difficult to develop waste compositions based on the categories proposed by Kudera et al. [1990], so we created five groups of waste on which to base the waste compositions. These groups are (1) transuranic waste, (2) fission product waste, (3) activation product waste, (4) mobile/volatile waste, and (5) sealed sources. The radionuclides within a given group share common characteristics (e.g., alpha-emitters, heat generators), and we believe that these groups adequately represent the DOE`s special-case waste potentially destined for greater confinement disposal at the NTS.
The purpose of the Reactor Pressure vessel Thermal Annealing Workshop was to provide a forum for US utilities and interested parties to discuss relevant experience and issues and identify potential solutions/approaches related to: An understanding of the potential benefits of thermal annealing for US commercial reactors; on-going technical research activities; technical aspects of a generic, full-scale, in-place vessel annealing demonstration; and the impact of economic, regulatory, and technical issues on the application of thermalannealingtechnology to US plants. Experts from the international nuclear reactor community were brought together to discuss issues regarding application of thermal annealing technology in the US and identify the steps necessary to commercialize this technology for US reactors. These proceedings contain all presentation materials discussed during the Workshop. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.
This SAND report summarizes the work completed for a Novel Project Research and Development LDRD project. In this research effort, new mathematical techniques from the theory of nonlinear generalized functions were applied to compute solutions of nonlinear hyperbolic field equations in nonconservative form. Nonconservative field equations contain products of generalized functions which are not defined in classical mathematics. Because of these products, traditional computational schemes are very difficult to apply and can produce erroneous numerical results. In the present work, existing first-order computational schemes based on results from the theory of nonlinear generalized functions were applied to simulate numerically two model problems cast in nonconservative form. From the results of these computational experiments, a higher-order Godunov scheme based on the piecewise parabolic method was proposed and tested. The numerical results obtained for the model problems are encouraging and suggest that the theory of nonlinear generalized functions provides a powerful tool for studying the complicated behavior of nonlinear hyperbolic field equations.
In situ design verification activities are being conducted in the North Ramp Starter Tunnel of the Yucca Mountain Project Exploratory Studies Facility. These activities include: monitoring the construction blasting, evaluating the damage to the rock mass associated with construction, assessing the rock mass quality surrounding the tunnel, monitoring the performance of the installed ground support, and monitoring the stability of the tunnel. In this paper, examples of the data that have been collected and preliminary conclusions from the data are presented.
The authors consider the following problem that arises in assembly planning: given an assembly, identify a subassembly that can be removed as a rigid object without disturbing the rest of the assembly. This is the assembly partitioning problem. Specifically, they consider planar assemblies of simple polygons and subassembly removal paths consisting of a single finite translation followed by a translation to infinity. They show that such a subassembly and removal path can be determined in O(n{sup 1.46}N{sup 6}) time, where n is the number of polygons in the assembly and N is the total number of edges and vertices of all the parts together. They then extend this formulation to removal paths consisting of a small number of finite translations, followed by a translation to infinity. In this case the algorithm runs in time polynomial in the number of parts, but exponential in the number of translations a path may contain.
Magnetoluminescence determined conduction-band and valence-band dispersion curves are presented for n-type InGaAs/GaAs stained-single-quantum well structures. The magnetic field range was 0 to 30 tesla, and the temperature varied between 4.2 and 77.4 K.
Effects of frequency, temperature and hydrostatic pressure on dielectric properties, molecular relaxations, and phase transitions of PVDF and a copolymer with 30 mol % trifluoroethylene are discussed. Pressure causes large slowing down of the {beta} molecular relaxations as well as large increases in the, ferroelectric transition temperatures and melting points, but the magnitudes of the effects are different for the different transitions. These effects can be understood in terms of pressure-induced hindrance of the molecular motions and/or reorientations. A unique application of these polymers as time-resolved dynamic stress gauges based on PVDF studies under very high pressure shock compression is discussed.
Design improvements for the International Atomic Energy Agency`s Spent Fuel Attribute Tester, recommended on the basis of an optimization study, were incorporated into a new instrument fabricated under the Finnish Support Programme. The new instrument was tested at a spent fuel storage pool on September 8 and 9, 1993. The result of two of the measurements have been compared with calculations. In both cases the calculated and measured pulse height spectra in good agreement and the {sup 137}Cs gamma peak signature from the target spent fuel element is present.
NATO and former Warsaw Pact nations have agreed to allow overflights of their countries in the interest of easing world tension. The United States has decided to implement two C-135 aircraft with a Synthetic Aperture Radar (SAR) that has a 3-meter resolution. This work is being sponsored by the Defense Nuclear Agency (DNA) and will be operational in Fall 1995. Since the SAR equipment must be exportable to foreign nations, a 20-year-old UPD-8 analog SAR system was selected as the front-end and refurbished for this application by Loral Defense Systems. Data processing is being upgraded to a currently exportable digital design by Sandia National Laboratories. Amplitude and phase histories will be collected during these overflights and digitized on VHS cassettes. Ground stations will use reduction algorithms to process the data and convert it to magnitude-detected images for member nations. System Planning Corporation is presently developing a portable ground station for use on the demonstration flights. Aircraft integration into the C-135 aircraft is being done by the Air Force at Wright-Patterson AFB, Ohio.
We describe the design and fabrication of two types of solid state moisture sensors, and discuss the results of an evaluation of the sensors for the detection of trace levels of moisture in semiconductor process gases. The first sensor is based on surface acoustic wave (SAW) technology. A moisture sensitive layer is deposited onto a SAW device, and the amount of moisture adsorbed on the layer produces a proportional shift in the operating frequency of the device. Sensors based on this concept have excellent detection limits for moisture in inert gas (100 ppb) and corrosive gas (150 ppb in HCl). The second sensor is a simple capacitor structure that uses porous silicon as a moisture-sensitive dielectric material. The detection limits of these sensors for moisture in inert gas are about 700 ppb prior to HCl exposure, and about 7 ppm following HCl exposure.
Several basic reasons are given to support the position that an integrated, systems methodology entailing probabilistic assessment offers the best means for addressing the problems in software safety. The recognized hard problems in software safety, or safety per se, and some of the techniques for hazard identification and analysis are then discussed relative to their specific strengths and limitations. The paper notes that it is the combination of techniques that will lead to safer systems, and that more experience, examples, and applications of techniques are needed to understand the limits to which software safety can be assessed. Lastly, some on-going project work at Sandia National Laboratories on developing a solution methodology is presented
The Australian Safeguards Office (ASO) and the US Department of Energy (DOE) have sponsored work under a bilateral agreement to implement a Remote Monitoring System (RMS) at an Australian nuclear site operated by the Australian Nuclear Science and Technology Organization (ANSTO). The RMS, designed by Sandia National Laboratories (SNL), was installed in February 1994 at the Dry Spent Fuel Storage Facility (DSFSF) located at Lucas Heights, Australia. The RMS was designed to test a number of different concepts that would be useful for unattended remote monitoring activities. The DSFSF located in Building 27 is a very suitable test site for a RMS. The RMS uses a network of low cost nodes to collect data from a number of different sensors and security devices. Different sensors and detection devices have been installed to study how they can be used to complement each other for C/S applications. The data collected from the network will allow a comparison of how the various types of sensors perform under the same set of conditions. A video system using digital compression collects digital images and stores them on a hard drive and a digital optical disk. Data and images from the storage area are remotely monitored via telephone from Canberra, Australia and Albuquerque, NM, USA. These remote monitoring stations operated by ASO and SNL respectively, can retrieve data and images from the RMS computer at the DSFSF. The data and images are encrypted before transmission. The Remote Monitoring System field tests have been operational for six months with good test results. Sensors have performed well and the digital images have excellent resolution. The hardware and software have performed reliably without any major difficulties. This paper summarizes the highlights of the prototype system and the ongoing field tests.
An important aspect of insider protection in production facilities is the monitoring of the movement of special nuclear material (SNM) and personnel. One system developed at Sandia National Labs for this purpose is the Personnel and Material Tracking System (PAMTRAK). PAMTRAK can intelligently integrate different sensor technologies and the security requirements of a facility to provide a unique capability in monitoring and tracking SNM and personnel. Currently many sensor technologies are used to track the location of personnel and SNM inside a production facility. These technologies are generally intrusive; they require special badges be worn by personnel, special tags be connected to material, and special detection devices be mounted in the area. Video technology, however, is non-intrusive because it does not require that personnel wear special badges or that special tags be attached to SNM. Sandia has developed a video-based image processing system consisting of three major components: the Material Monitoring-Subsystem (MMS), the Personnel Tracking Subsystem (PTS) and the Item Recognition Subsystem (IRS). The basic function of the MMS is to detect movements of SNM, that occur in user-defined regions of interest (ROI) from multiple cameras; these ROI can be of any shape and size. The purpose of the PTS is to track location of personnel in an area using multiple cameras. It can also be used to implement the two-person rule or to detect unauthorized personnel in a restricted area. Finally, the IRS can be used for the recognition and inventory of SNM in a working area. It can also generate a log record on the status of each SNM. Currently the MMS is integrated with PAMTRAK to complement other monitoring technologies in the system. The paper will discuss the system components and their implementations, and describe current enhancements as well as future work.
Sticky foam is an extremely tacky, tenacious material used to entangle and impair an individual. It was developed at Sandia National Laboratories (SNL) in the late 1970`s for usage in nuclear safeguards and security applications. In late 1992, the National Institute of Justice (NIJ), the research arm of the Department of Justice, began a project with SNL to determine the applicability of sticky foam for law enforcement usage. The objectives of the project were to develop a dispenser capable of firing sticky foam, to conduct an extensive toxicology review of sticky foam (formulation SF-283), to test the developed dispenser and sticky foam effectiveness on SNL volunteers acting out prison and law enforcement scenarios, and to have the dispenser and sticky foam further evaluated by correctional representatives. This paper discusses the results of the project.
MOS oxides have been fabricated by oxidation of silicon in N{sub 2}O. Processes studied include oxidation in N{sub 2}O alone, and two-step oxidation in O{sub 2} followed by N{sub 2}O. For both oxides, a nitrogen-rich layer with a peak N concentration of {approximately} 0.5 at. % is observed at the Si-SiO{sub 2} interface with SIMS. Electrical characteristics of N{sub 2}O oxides, such as breakdown and defect generation, are generally improved, especially for the two-step process. Drawbacks typically associated with NH{sub 3}-nitrided oxides such as high fixed oxide charge and enhanced electron trapping, are not observed in N{sub 2}O oxides, which is probably due to their smaller nitrogen content.
The Explosive Inventory and Information System (EIS) is being developed and implemented by Sandia National Laboratories (SNL) to incorporate a cradle to grave structure for all explosives and explosive containing devices and assemblies at SNL from acquisition through use, storage, reapplication, transfer or disposal. The system does more than track all material inventories. It provides information on material composition, characteristics, shipping requirements; life cycle cost information, plan of use; and duration of ownership. The system also provides for following the processes of explosive development; storage review; justification for retention; Resource, Recovery and Disposition Account (RRDA); disassembly and assembly; and job description, hazard analysis and training requirements for all locations and employees involved with explosive operations. In addition, other information systems will be provided through the system such as the Department of Energy (DOE) and SNL Explosive Safety manuals, the Navy`s Department of Defense (DoD) Explosive information system, and the Lawrence Livermore National Laboratories (LLNL) Handbook of Explosives.
This paper describes a method of reducing the mechanical stress caused when a ferrite pot core is encapsulated in a rigid epoxy. the stresses are due to the differences of coefficient of thermal expansion between the two materials. A stress relief medium, phenolic micro-balloon-filled, syntactic polysulfide, is molded into the shape of the pot core. The molded polysulfide is bonded to the core prior to encapsulation. The new package design has made a significant difference in the ability to survive temperature cycles.
This paper provides an overview of the methodology used in a probabilistic transportation risk assessment conducted to assess the probabilities and consequences of inadvertent dispersal of radioactive materials arising from severe transportation accidents. The model was developed for the Defense Program Transportation Risk Assessment (DPTRA) study. The analysis incorporates several enhancements relative to previous risk assessments of hazardous materials transportation including newly-developed statistics on the frequencies and severities of tractor semitrailer accidents and detailed route characterization using the 1990 Census data.
Protecting sensitive items from undetected tampering in an unattended environment is crucial to the success of non-proliferation efforts relying on the verification of critical activities. Tamper Indicating Packaging (TIP) technologies are applied to containers, packages, and equipment that require an indication of a tamper attempt. Examples include: the transportation and storage of nuclear material, the operation and shipment of surveillance equipment and monitoring sensors, and the retail storage of medicine and food products. The spectrum of adversarial tampering ranges from attempted concealment of a pin-hole sized penetration to the complete container replacement, which would involve counterfeiting efforts of various degrees. Sandia National Laboratories (SNL) has developed a technology base for advanced TIP materials, sensors, designs, and processes which can be adapted to various future monitoring systems. The purpose of this technology base is to investigate potential new technologies, and to perform basic research of advanced technologies. This paper will describe the theory of TIP technologies and recent investigations of TIP technologies at SNL.
Becoming aware of the significant events of the past four years and their effect on the expectations to international safeguards, it is necessary to reflect on which direction the development of nuclear safeguards in a new era needs to take and the implications. The lime proven monitoring techniques, based on quantitative factor`s and demonstrated universal application, have shown their merit. However, the new expectations suggest a possibility that a future IAEA safeguards system could rely more heavily on the value of a comprehensive, transparent and open implementation regime. Within such a regime, the associated measures need to be determined and technological support identified. This paper will identify the proven techniques which, with appropriate implementation support, could most quickly make available additional measures for a comprehensive, transparent and open implementation regime. In particular, it will examine the future of Integrated Monitoring Systems and Remote Monitoring in international safeguards, including technical and other related factors.