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Analyses of containment structures with corrosion damage
Corrosion damage to a nuclear power plant containment structure can degrade the pressure capacity of the vessel. For the low-carbon, low- strength steels used in containments, the effect of corrosion on material properties is discussed. Strain-to-failure tests, in uniaxial tension, have been performed on corroded material samples. Results were used to select strain-based failure criteria for corroded steel. Using the ABAQUS finite element analysis code, the capacity of a typical PWR Ice Condenser containment with corrosion damage has been studied. Multiple analyses were performed with the locations of the corrosion the containment, and the amount of corrosion varied in each analysis.
Date:
December 31, 1996
Creator:
Cherry, J.L.
Object Type:
Article
System:
The UNT Digital Library
Analysis and design methodology for the development of optimized, direct-detection CO{sub 2} DIAL receivers
The analysis methodology and corresponding analytical tools for the design of optimized, low-noise, hard target return CO{sub 2} Differential Absorption Lidar (DIAL) receiver systems implementing both single element detectors and multi-pixel imaging arrays for passive/active, remote-sensing applications are presented. System parameters and components composing the receiver include: aperture, focal length, field of view, cold shield requirements, image plane dimensions, pixel dimensions, pixel pitch and fill factor, detection quantum efficiency, optical filter requirements, amplifier and temporal sampling parameters. The performance analysis is accomplished by calculating the system`s CO{sub 2} laser range response, total noise, optical geometric form factor and optical resolution. The noise components include speckle, photon noise due to signal, scene and atmospheric background, cold shield, and electronic noise. System resolution is simulated through cascaded optical transfer functions and includes effects due to atmosphere, optics, image sampling, and system motion. Experimental results of a developmental single-element detector receiver designed to detect 100 ns wide laser pulses (10 - 100 kHz pulse repetition rates) backscattered from hard-targets at nominal ranges of 10 km are presented. The receiver sensitivity is near-background noise limited, given an 8.5-11.5 {mu}m radiant optical bandwidth, with the total noise floor spectrally white for maximum pulse averaging efficiency.
Date:
December 31, 1996
Creator:
Cooke, B.J.; Laubscher, B.E. & Cafferty, M.
Object Type:
Article
System:
The UNT Digital Library
Analysis and performance of adjacent-cell preconditioners for accelerating multidimensional transport calculations
The formal development of the Adjacent-cell Preconditioner (AP) and its implementation in the TORT code are briefly reviewed. Based on earlier experience with diffusion type acceleration, and excellent results in slab geometry the reciprocal averaging formula is used to mix the preconditioner elements across material and mesh discontinuities. Numerical testing of the method employing the Burre Suite of Test Problems (BSTeP), a collection of 144 cases covering a wide range in parameter space, using AP, Partial Current Rebalance (PCR), and TWODANT`s Diffusion Synthetic Acceleration (DSA) is presented. While AP outperforms the other two methods for the majority of the cases included in BSTeP it consumes many more iterations than can be explained by spectral analysis of the homogeneous model problem in cases with sharp material discontinuity. In order to verify this undesirable behavior and explore potential remedies a model problem, the Periodic Horizontal Interface (PHI), is developed that permits discontinuity of nuclear properties and cell height across the interface. Fourier mode decomposition is applied to AP with the reciprocal averaging mixing formula for the PHI configuration and shown to possess a spectral radius that approaches unity as the material discontinuity gets larger. The question of whether an unconditionally stable AP …
Date:
December 31, 1996
Creator:
Azmy, Y.Y.
Object Type:
Article
System:
The UNT Digital Library
Analysis and simulation of a small-angle neutron scattering instrument on a 1 MW long pulse spallation source
We studied the design and performance of a small-angle neutron scattering (SANS) instrument for a proposed 1 MW, 60 Hz long pulsed spallation source at the Los Alamos Neutron Science Center (LANSCE). An analysis of the effects of source characteristics and chopper performance combined with instrument simulations using the LANSCE Monte Carlo instrument simulations package shows that the T{sub 0} chopper should be no more than 5 m from the source with the frame overlap and frame definition choppers at 5.6 and greater than 7 m, respectively. The study showed that an optimal pulse structure has an exponential decaying tail with {tau} {approx} 750 {mu}s. The Monte Carlo simulations were used to optimize the LPSS SANS, showing that an optimal length is 18 m. The simulations show that an instrument with variable length is best to match the needs of a given measurement. The performance of the optimized LPSS instrument was found to be comparable with present world standard instruments.
Date:
December 31, 1996
Creator:
Olah, G.A.; Hjelm, R.P. & Lujan, M. Jr.
Object Type:
Article
System:
The UNT Digital Library
Analysis of cloud radiative forcing and feedback in a climate GCM. Final report
The principal objectives of the research supported at the Goddard Institute for Space Studies (GISS) by the Atmospheric Radiation Measurement (ARM) Program for a three year period commencing September 1990, were: (1) to improve and validate the radiation parameterizations in the GISS GCM through model intercomparisons with line-by-line calculations and through comparisons with ARM observations; (2) to improve the GISS GCM diagnostic output to enable more effective comparisons to global cloud/radiation data sets; and (3) to use ARM data to develop improved parameterization of clouds in the GCM and to study the interaction of dynamics and radiation. The ARM Program support has made it possible to establish and support an active and productive research group at GISS specializing in radiative transfer and cloud process modeling in support of improving the performance of a climate GCM.
Date:
December 31, 1996
Creator:
Lacis, A.
Object Type:
Report
System:
The UNT Digital Library
Analysis of costs-benefits tradeoffs of complex security systems
Essential to a systems approach to design of security systems is an analysis of the cost effectiveness of alternative designs. While the concept of analysis of costs and benefits is straightforward, implementation can be at the least tedious and, for complex designs and alternatives, can become nearly intractable without the help of structured analysis tools. PACAIT--Performance and Cost Analysis Integrated Tools--is a prototype tool. The performance side of the analysis collates and reduces data from ASSESS, and existing DOE PC-based security systems performance analysis tool. The costs side of the analysis uses ACE, an existing DOD PC-based costs analysis tool. Costs are reported over the full life-cycle of the system, that is, the costs to procure, operate, maintain and retire the system and all of its components. Results are collected in Microsoft{reg_sign} Excel workbooks and are readily available to analysts and decision makers in both tabular and graphical formats and at both the system and path-element levels.
Date:
December 31, 1996
Creator:
Hicks, M. J.
Object Type:
Article
System:
The UNT Digital Library
Analysis of ultra-relativistic charged particle beam and stretched wire measurement interactions with cylindrically symmetric structures
The beam impedance and wakefield are quantities which describe the stability of charged particles in their trajectory within an accelerator. The stretched wire measurement technique is a method which estimates the beam impedance and wakefield. Definitions for the beam impedance, the wakefield, and the stretched wire measurement are presented. A pillbox resonator with circular beampipes is studied for its relatively simple profile and mode structure. Theoretical predictions and measurement data are presented for the interaction of various charged particle beams and center conductor geometries between the cavity and beampipe. Time domain predictions for the stretched wire measurement and wakefield are presented and are shown to be a linear interaction.
Date:
December 31, 1996
Creator:
Deibele, C.E.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Annealing studies of visible light emission from silicon nanocrystals produced by implantation
The annealing behavior of silicon implanted SiO{sub 2} layers is studied using continuous and time-gated photoluminescence (PL). Two PL emission bands are observed. A band centered at 560 nm is present in as implanted samples and it is still observed after 1000 {degrees}C annealing. The emission time is fast (0.2 -2 ns). A second band centered at 780 nm further increases when hydrogen annealing was performed. The emission time is long (1 {mu}s - 0.3 ms).
Date:
December 31, 1996
Creator:
Ghislotti, G.; Nielsen, B. & Di Mauro, L.F.
Object Type:
Article
System:
The UNT Digital Library
Annual site environmental report for calendar year 1996
The Western Area Power Administration (Western) has established a formal environmental protection, auditing, monitoring, and planning program. Western markets power from 56 hydroelectric power generating plants in its service area. Additionally, Western markets the US entitlement from the Navajo coal-fired plant near Page, Arizona. The significant environmental projects and issues Western was involved with in 1996 are discussed in this report.
Date:
December 31, 1996
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Anthropology and decision making about chronic technological disasters: Mixed waste remediation on the Oak Ridge Reservation
This paper discusses two related case studies of decision making about the remediation of mixed (hazardous and radioactive) wastes on the Oak Ridge Reservation in Tennessee. The three goals of the paper are to (1) place current decision-making efforts in the varied and evolving social, political, regulatory, economic, and technological contexts in which they occur; (2) present definitions and attributes of {open_quotes}successful{close_quotes} environmental decision making from the perspectives of key constituency groups that participate in decision making; and (3) discuss the role of anthropology in addressing environmental decision making. Environmental decision making about remediation is extraordinarily complex, involving human health and ecological risks; uncertainties about risks, technological ability to clean up, the financial costs of clean up; multiple and sometimes conflicting regulations; social equity and justice considerations; and decreasing budgets. Anthropological theories and methods can contribute to better understanding and, potentially, to better decision making.
Date:
December 31, 1996
Creator:
Wolfe, A.K. & Schweitzer, M.
Object Type:
Article
System:
The UNT Digital Library
{anti p} and {anti {Lambda}} production in Si+Au collisions at the AGS
{anti {ital p}} and {anti {Lambda}} production in central Si + Au collisions has been measured by E589 at the BNL-AGS. Preliminary {ital m}{sub {perpendicular}} spectra are presented for {anti {ital p}}`s and {anti {Lambda}}`s. The {ital dn/dy} distribution for {anti {ital p}}`s is also presented. Based on the {anti {ital p}} and {anti {Lambda}} measurements, {anti {Lambda}}/{anti {ital p}} ratios are calculated in the rapidity range of 1.1-1.5.
Date:
December 31, 1996
Creator:
Wu, Yuedong & Collaboration, E802 /E859
Object Type:
Article
System:
The UNT Digital Library
Antihydrogen production and precision experiments
The study of CPT invariance with the highest achievable precision in all particle sectors is of fundamental importance for physics. Equally important is the question of the gravitational acceleration of antimatter. In recent years, impressive progress has been achieved in capturing antiprotons in specially designed Penning traps, in cooling them to energies of a few milli-electron volts, and in storing them for hours in a small volume of space. Positrons have been accumulated in large numbers in similar traps, and low energy positron or positronium beams have been generated. Finally, steady progress has been made in trapping and cooling neutral atoms. Thus the ingredients to form antihydrogen at rest are at hand. Once antihydrogen atoms have been captured at low energy, spectroscopic methods can be applied to interrogate their atomic structure with extremely high precision and compare it to its normal matter counterpart, the hydrogen atom. Especially the 1S-2S transition, with a lifetime of the excited state of 122 msec and thereby a natural linewidth of 5 parts in 10{sup 16}, offers in principle the possibility to directly compare matter and antimatter properties at a level of 1 part in 10{sup 16}.
Date:
December 31, 1996
Creator:
Nieto, M. M.; Goldman, T. & Holzscheiter, M. H.
Object Type:
Article
System:
The UNT Digital Library
Antiproton production in 11.7 AGeV/c Au+Au collisions from E866
We present antiproton production in 11.7 AGeV/c Au+Au collisions measured in a wide transverse-mass coverage from the AGS-E866 experiment. We show indications for strong absorption effects of antiprotons in Au+Au collisions through comparison with p+A and Si+A collisions, and centrality dependence in Au+Au collisions.
Date:
December 31, 1996
Creator:
Sako, Hiroyuki & Collaboration, E866
Object Type:
Article
System:
The UNT Digital Library
Application of MCNP{trademark} to storage facility dose rate assessment
The MCNP code is widely used in the determination of neutral particle dose rate analyses. In this paper we examine the application of MCNP to several storage facilities containing special nuclear material, SNM, wherein the neutron dose rate is the primary quantity of interest. In particular, we describe the special geometry, modeling assumptions, and physics considerations encountered in each of three applications.
Date:
December 31, 1996
Creator:
Urban, W. T.; Roberts, R. R.; Estes, G. P. & Taylor, W. M.
Object Type:
Article
System:
The UNT Digital Library
Application of metallic nanoparticle suspensions in advanced cooling systems
In the development of energy-efficient heat transfer fluids that are required in many cooling applications, low thermal conductivity is a primary limitation. However, it is well known that at room temperature, metals in solid form have orders-of-magnitude higher thermal conductivities than those of fluids. Therefore, the thermal conductivities of fluids that contain suspended solid metallic particles are expected to be significantly enhanced over those of conventional heat transfer fluids. In fact, numerous theoretical and experimental studies of the effective thermal conductivity of dispersions that contain solid particles have been conducted since Maxwell`s theoretical was published more than 100 years ago. However, all of the studies on thermal conductivity of suspensions have been confined to millimeter- or micrometer-sized particles.
Date:
December 31, 1996
Creator:
Lee, S. & Choi, S. U. S.
Object Type:
Article
System:
The UNT Digital Library
Application of small specimens to fracture mechanics characterization of irradiated pressure vessel steels
In this study, precracked Charpy V-notch (PCVN) specimens were used to characterize the fracture toughness of unirradiated and irradiated reactor pressure vessel steels in the transition region by means of three-point static bending. Fracture toughness at cleavage instability was calculated in terms of elastic-plastic K{sub Jc} values. A statistical size correction based upon weakest-link theory was performed. The concept of a master curve was applied to analyze fracture toughness properties. Initially, size-corrected PCVN data from A 533 grade B steel, designated HSST Plate O2, were used to position the master curve and a 5% tolerance bound for K{sub Jc} data. By converting PCVN data to IT compact specimen equivalent K{sub Jc} data, the same master curve and 5% tolerance bound curve were plotted against the Electric Power Research Institute valid linear-elastic K{sub Jc} database and the ASME lower bound K{sub Ic} curve. Comparison shows that the master curve positioned by testing several PCVN specimens describes very well the massive fracture toughness database of large specimens. These results give strong support to the validity of K{sub Jc} with respect to K{sub Ic} in general and to the applicability of PCVN specimens to measure fracture toughness of reactor vessel steels in particular. …
Date:
December 31, 1996
Creator:
Sokolov, M. A.; Wallin, K. & McCabe, D. E.
Object Type:
Article
System:
The UNT Digital Library
Application of stochastic differential geometry to the term structure of interst rates in developed markets
This paper deals with further developments of the new theory that applies stochastic differential geometry (SDG) to dynamics of interest rates. We examine mathematical constraints on the evolution of interest rate volatilities that arise from stochastic differential calculus under assumptions of an arbitrage free evolution of zero coupon bonds and developed markets (i.e., none of the party/factor can drive the whole market). The resulting new theory incorporates the Heath-Jarrow-Morton (HJM) model of interest rates and provides new equations for volatilities which makes the system of equations for interest rates and volatilities complete and self consistent. It results in much smaller amount of volatility data that should be guessed for the SDG model as compared to the HJM model. Limited analysis of the market volatility data suggests that the assumption of the developed market is violated around maturity of two years. Such maturities where the assumptions of the SDG model are violated are suggested to serve as boundaries at which volatilities should be specified independently from the model. Our numerical example with two boundaries (two years and five years) qualitatively resembles the market behavior. Under some conditions solutions of the SDG model become singular that may indicate market crashes. More detail …
Date:
December 31, 1996
Creator:
Taranenko, Y. & Barnes, C.
Object Type:
Article
System:
The UNT Digital Library
Application of the smart portal in transportation
Under a program sponsored by the Department of Energy, the Oak Ridge complex is developed a ``Portal-of-the-Future``, or ``smart portal``. This is a security portal for vehicular traffic which is intended to quickly detect explosives, hidden passengers, etc. It uses several technologies, including microwaves, weigh-in-motion, digital image processing, and electroacoustic wavelet-based heartbeat detection. A novel component of particular interest is the Enclosed Space Detection System (ESDS), which detects the presence of persons hiding in a vehicle. The system operates by detecting the presence of a human ballistocardiographic signature. Each time the heart beats, it generates a small but measurable shock wave that propagates through the body. The wave, whose graph is called a ballistocardiogram, is the mechanical analog of the electrocardiogram, which is routinely used for medical diagnosis. The wave is, in turn, coupled to any surface or object with which the body is in contact. If the body is located in an enclosed space, this will result in a measurable deflection of the surface of the enclosure. Independent testing has shown ESDS to be highly reliable. The technologies used in the smart portal operate in real time and allow vehicles to be checked through the portal in much less …
Date:
December 31, 1996
Creator:
Kercel, S. W.; Baylor, V. M.; Dress, W. B.; Hickerson, T. W.; Jatko, W. B.; Labaj, L. E. et al.
Object Type:
Article
System:
The UNT Digital Library
Applications of the thermogravimetric analysis in the study of fossil fuels
Thermogravimetric analysis (TGA) of coal and resid liquids and coal and resid solid residues, produced in coal liquefaction and coal- derived resid hydroprocessing in SCTBR (short contact time batch reactor), provides a sensitive, rapid, reproducible means of studying kinetics and mechanisms of fossil fuel conversion processes. SimDis TGA and custom built TGA system for distillation provide unique means to characterize liquid fuels for boiling point distribution. TGA provides information about various weight loss processes that can be a reflection of physical and chemical structure of fossil fuel samples. This technique can also yield TG scanning parameters, such as volatile matter, fixed carbon, ash, etc., for monitoring the conversion processes. One example is onset and rate of retrograde reactions during coal liquefaction.
Date:
December 31, 1996
Creator:
Huang, He; Wang, Keyu; Wang, Shaojie; Klein, M. T. & Calkins, W. H.
Object Type:
Article
System:
The UNT Digital Library
Applications of virtual reality to nuclear safeguards and non-proliferation
This paper presents several applications of virtual reality relevant to the areas of nuclear safeguards and non-proliferation. Each of these applications was developed to the prototype stage at Sandia National Laboratories` Virtual Reality and Intelligent Simulation laboratory. These applications include the use of virtual reality for facility visualization, training of inspection personnel, and security and monitoring of nuclear facilities.
Date:
December 31, 1996
Creator:
Stansfield, S.
Object Type:
Article
System:
The UNT Digital Library
Approaches for preventing and mitigating accidental gaseous chemical releases
This paper presents a review of approaches to prevent and mitigate accidental releases of toxic and flammable gases. The prevention options are related to: choosing safer processes and materials, preventing initiating events, preventing or minimizing releases, and preventing human exposures. the mitigation options include: secondary confinement, de-inventory, vapor barriers, and water sprays/monitors. Guidelines for the design and operation of effective post-release mitigation systems are also presented.
Date:
December 31, 1996
Creator:
Fthenakis, V. M.
Object Type:
Article
System:
The UNT Digital Library
Approaches to accident analysis in recent US Department of Energy environmental impact statements
A review of accident analyses in recent US Department of Energy (DOE) Environmental Impact Statements (EISs) was conducted to evaluate the consistency among approaches and to compare these approaches with existing DOE guidance. The review considered several components of an accident analysis: the overall scope, which in turn should reflect the scope of the EIS; the spectrum of accidents considered; the methods and assumptions used to determine frequencies or frequency ranges for the accident sequences; and the assumption and technical bases for developing radiological and chemical atmospheric source terms and for calculating the consequences of airborne releases. The review also considered the range of results generated with respect to impacts on various worker and general populations. In this paper, the findings of these reviews are presented and methods recommended for improving consistency among EISs and bringing them more into line with existing DOE guidance.
Date:
December 31, 1996
Creator:
Mueller, C.; Folga, S. & Nabelssi, B.
Object Type:
Article
System:
The UNT Digital Library
An articulatorily constrained, maximum entropy approach to speech recognition and speech coding
Hidden Markov models (HMM`s) are among the most popular tools for performing computer speech recognition. One of the primary reasons that HMM`s typically outperform other speech recognition techniques is that the parameters used for recognition are determined by the data, not by preconceived notions of what the parameters should be. This makes HMM`s better able to deal with intra- and inter-speaker variability despite the limited knowledge of how speech signals vary and despite the often limited ability to correctly formulate rules describing variability and invariance in speech. In fact, it is often the case that when HMM parameter values are constrained using the limited knowledge of speech, recognition performance decreases. However, the structure of an HMM has little in common with the mechanisms underlying speech production. Here, the author argues that by using probabilistic models that more accurately embody the process of speech production, he can create models that have all the advantages of HMM`s, but that should more accurately capture the statistical properties of real speech samples--presumably leading to more accurate speech recognition. The model he will discuss uses the fact that speech articulators move smoothly and continuously. Before discussing how to use articulatory constraints, he will give a …
Date:
December 31, 1996
Creator:
Hogden, J.
Object Type:
Report
System:
The UNT Digital Library
Ash and pulverized coal deposition in combustors and gasifiers. Quarterly technical progress report, July 1, 1996--September 30, 1996
The computational model for simulating particle motions in turbulent flows was further developed and used to analyze the transport and dispersion of particles in a recirculating flow region. The model for resuspension of particles from surfaces in a gas flow is also further developed; it accounts for the surface adhesion as well as hydrodynamic forces and torques. It includes effects of the structure of near wall turbulent flows as well as surface roughness. In addition, a direct numerical simulation procedure for analyzing the particle removal process in turbulent gas flows is also developed. The sublayer model for evaluating the particle deposition in turbulent flows is being extended to include the effect of particle rebound. Further progress was also made in the experimental study of glass fiber transport and deposition in the aerosol wind tunnel.
Date:
December 31, 1996
Creator:
Ahmadi, G.
Object Type:
Report
System:
The UNT Digital Library