Resource Type

RAMI modeling of plant systems for proposed tritium production and extraction facilities (open access)

RAMI modeling of plant systems for proposed tritium production and extraction facilities

The control of life-cycle cost is a primary concern during the development, construction, operation, and decommissioning of DOE systems and facilities. An effective tool that can be used to control these costs, beginning with the design stage, is called a reliability, availability, maintainability, and inspectability analysis or, simply, RAMI for short. In 1997, RAMI technology was introduced to the Savannah River Site with applications at the conceptual design stage beginning with the Accelerator Production of Tritium (APT) Project and later extended to the Commercial Light Water Reactor (CLWR) Tritium Extraction Facility (TEF) Project. More recently it has been applied to the as-build Water Treatment Facilities designed for ground water environmental restoration. This new technology and database was applied to the assessment of balance-of-plant systems for the APT Conceptual Design Report. Initial results from the Heat Removal System Assessment revealed that the system conceptual design would cause the APT to fall short of its annual production goal. Using RAM technology to immediately assess this situation, it was demonstrated that the product loss could be gained back by upgrading the system's chiller unit capacity at a cost of less than $1.3 million. The reclaimed production is worth approximately $100 million. The RAM …
Date: April 5, 2000
Creator: Blanchard, A.
System: The UNT Digital Library
Soil sample preparation using microwave digestion for uranium analysis (open access)

Soil sample preparation using microwave digestion for uranium analysis

A new sample preparation procedure has been developed for digestion of soil samples for uranium analysis. The technique employs a microwave oven digestion system to digest the sample and to prepare it for separation chemistry and analysis. The method significantly reduces the volume of acids used, eliminates a large fraction of acid vapor emissions, and speeds up the analysis time. The samples are analyzed by four separate techniques: Gamma Spectrometry, Alpha Spectroscopy using the open digestion method, Kinetic Phosphorescence Analysis (KPA) using open digestion, and KPA by Microwave digestion technique. The results for various analytical methods are compared and used to confirm the validity of the new procedure. The details of the preparation technique along with its benefits are discussed.
Date: April 5, 2000
Creator: Mohagheghi, Amir H.; Preston, Rose; Akbarzadeh, Mansoor & Bakhtiar, Steven
System: The UNT Digital Library
100% foundry compatible packaging and full wafer release and die separation technique for surface micromachined devices (open access)

100% foundry compatible packaging and full wafer release and die separation technique for surface micromachined devices

A completely foundry compatible chip-scale package for surface micromachines has been successfully demonstrated. A pyrex (Corning 7740) glass cover is placed over the released surface micromachined die and anodically bonded to a planarized polysilicon bonding ring. Electrical feedthroughs for the surface micromachine pass underneath the polysilicon sealing ring. The package has been found to be hermetic with a leak rate of less than 5 x 10{sup {minus}8} atm cm{sup {minus}3}/s. This technology has applications in the areas of hermetic encapsulation and wafer level release and die separation.
Date: April 6, 2000
Creator: Oliver, Andrew D. & Matzke, Carolyn M.
System: The UNT Digital Library
Assessment of Cable Aging Using Condition Monitoring Techniques (open access)

Assessment of Cable Aging Using Condition Monitoring Techniques

Electric cables in nuclear power plants suffer degradation during service as a result of the thermal and radiation environments in which they are installed. Instrumentation and control cables are one type of cable that provide an important role in reactor safety. Should the polymeric cable insulation material become embrittled and cracked during service, or during a loss-of-coolant-accident (LOCA) and when steam and high radiation conditions are anticipated, failure could occur and prevent the cables from fulfilling their intended safety function(s). A research program is being conducted at Brookhaven National Laboratory to evaluate condition monitoring (CM) techniques for estimating the amount of cable degradation experienced during in-plant service. The objectives of this program are to assess the ability of the cables to perform under a simulated LOCA without losing their ability to function effectively, and to identify CM techniques which may be used to determine the effective lifetime of cables. The cable insulation materials tested include ethylene propylene rubber (EPR) and cross-linked polyethylene (XLPE). Accelerated aging (thermal and radiation) to the equivalent of 40 years of service was performed, followed by exposure to simulated LOCA conditions. The effectiveness of chemical, electrical, and mechanical condition monitoring techniques are being evaluated. Results indicate …
Date: April 6, 2000
Creator: Grove, E.; Lofaro, R.; Soo, P.; Villaran, M. & Hsu, F.
System: The UNT Digital Library
Calibration of parallel kinematic devices using sequential determination of kinematic parameters (open access)

Calibration of parallel kinematic devices using sequential determination of kinematic parameters

In PKM Machines, the Cartesian position and orientation of the tool point carried on the platform is obtained from a kinematic model of the particular machine. Accurate positioning of these machines relies on the accurate knowledge of the parameters of the kinematic model unique to the particular machine. The parameters in the kinematic model include the spatial locations of the joint centers on the machine base and moving platform, the initial strut lengths, and the strut displacements. The strut displacements are readily obtained from sensors on the machine. However, the remaining kinematic parameters (joint center locations, and initial strut lengths) are difficult to determine when these machines are in their fully assembled state. The size and complexity of these machines generally makes it difficult and somewhat undesirable to determine the remaining kinematic parameters by direct inspection such as in a coordinate measuring machine. In order for PKMs to be useful for precision positioning applications, techniques must be developed to quickly calibrate the machine by determining the kinematic parameters without disassembly of the machine. A number of authors have reported techniques for calibration of PKMs (Soons, Masory, Zhuang et. al., Ropponen). In two other papers, the authors have reported on work …
Date: April 6, 2000
Creator: JOKIEL JR.,BERNHARD; BIEG,LOTHAR F. & ZIEGERT,JOHN C.
System: The UNT Digital Library
Characterization of Thermal Sprayed Aluminum and Stainless Steel Coatings for Clean Laser Enclosures (open access)

Characterization of Thermal Sprayed Aluminum and Stainless Steel Coatings for Clean Laser Enclosures

Surfaces of steel structures that enclose high-fluence, large-beam lasers have conventional and unconventional requirements. Aside from rust prevention, the surfaces must resist laser-induced degradation and the contamination of the optical components. The latter requires a surface that can be precision cleaned to low levels of particulate and organic residue. In addition, the surface treatment for the walls should be economical to apply because of the large surface areas involved, and accommodating with intricate joint geometries. Thermal sprayed coatings of aluminum (Al) and stainless steel are candidate surface materials. Coatings are produced and characterized for porosity, smoothness, and hardness. These properties have a bearing on the cleanliness of the coating. The laser resistance of Al and 3 16L coatings are given. The paper summarizes the characterization of twin-wire-arc deposited Al, high-velocity-oxygen-fueled (HVOF) deposited Al, flame-sprayed 316L, and HVOF deposited316L. The most promising candidate coating is that of HVOF Al. This Al coating has the lowest porosity (8%) compared the other three coatings and relatively low hardness (100 VHN). The as-deposited roughness (Ra) is 433 pinches, but after a quick sanding by hand, the roughness decreased to 166 pinches. Other post-coat treatments are discussed. HVOF aluminum coatings are demonstrated. Al coatings are …
Date: April 6, 2000
Creator: Chow, R; Decker, T A; Gansert, R V & Gansert, D
System: The UNT Digital Library
Control of the interparticle spacing in gold nanoparticle superlattices (open access)

Control of the interparticle spacing in gold nanoparticle superlattices

The authors have investigated the formation of 2-D and 3-D superlattices of Au nanoclusters synthesized in nonionic inverse micelles, and capped with alkyl thiol ligands, with alkane chains ranging from C{sub 6} to C1{sub 18}. The thiols are found to play a significant role in the ripening of these nanoclusters, and in the formation of superlattices. Image processing techniques were developed to reliably extract from transmission electron micrographs (TEMs) the particle size distribution, and information about the superlattice domains and their boundaries. The latter permits one to compute the intradomain vector pair correlation function, from which one can accurately determine the lattice spacing and the coherent domain size. From these data the gap between the particles in the coherent domains can be determined as a function of the thiol chain length. It is found that as the thiol chain length increases, the nanoclusters become more polydisperse and larger, and the gaps between particles within superlattice domains increases. Annealing studies at elevated temperatures confirm nanocluster ripening. Finally, the effect of the particle gaps on physical properties is illustrated by computing the effective dielectric constant, and it is shown that the gap size now accessible in superlattices is rather large for dielectric …
Date: April 6, 2000
Creator: Martin,James E.; Wilcoxon, Jess P.; Odinek, Judy G. & Provencio, Paula P.
System: The UNT Digital Library
Nanofabricated SiO{sub 2}-Si-SiO{sub 2} Resonant Tunneling Diodes (open access)

Nanofabricated SiO{sub 2}-Si-SiO{sub 2} Resonant Tunneling Diodes

Resonance Tunneling Diodes (RTDs) are devices that can demonstrate very high-speed operation. Typically they have been fabricated using epitaxial techniques and materials not consistent with standard commercial integrated circuits. The authors report here the first demonstration of SiO{sub 2}-Si-SiO{sub 2} RTDs. These new structures were fabricated using novel combinations of silicon integrated circuit processes.
Date: April 6, 2000
Creator: Fleming, James G.; Chow, Kai-Cheung & Lin, Shawn-Yu
System: The UNT Digital Library
The Potential of Fast Ignition and Related Experiments With a Petawatt Laser Facility (open access)

The Potential of Fast Ignition and Related Experiments With a Petawatt Laser Facility

A model of energy gain induced by fast ignition of thermonuclear burn in compressed deuterium-tritium fuel, is used to show the potential for 300x gain with a driver energy of 1 M J, if the National Ignition Facility (NIF) were to be adapted for fast ignition. The physics of fast ignition has been studied using a petawatt laser facility at the Lawrence Livermore National Laboratory. Laser plasma interaction in a preformed plasma on a solid target leads to relativistic self-focusing evidenced by x-ray images. Absorption of the laser radiation transfers energy to an intense source of relativistic electrons. Good conversion efficiency into a wide angular distribution is reported. Heating by the electrons in solid density CD{sub 2} produces 0.5 to 1/keV temperature, inferred from the D-D thermo-nuclear neutron yield.
Date: April 6, 2000
Creator: Key, M. H.; Campbell, E. M.; Cowan, T. E.; Hatchett, S. P.; Henry, E. A.; Koch, J. A. et al.
System: The UNT Digital Library
RECENT WORK ON RENORMALIZATION GROUP FOR THE COLORED GLASS CONDENSATE. (open access)

RECENT WORK ON RENORMALIZATION GROUP FOR THE COLORED GLASS CONDENSATE.

None
Date: April 6, 2000
Creator: McLerran, L.
System: The UNT Digital Library
Report of the 1997 National Conference of Black Physics Students (open access)

Report of the 1997 National Conference of Black Physics Students

The 1997 National Conference of Black Physics Students (NCBPS) was hosted by the Department of Physics, Massachusetts Institute of Technology. The meeting occurred in February 1997. The focus of the Conference was on the diversity of research and career options available with a background in physics. The number of Black graduate and undergraduate students attending 1997 NCBPS was 210. The majority of the undergraduate students were from Historically Black Colleges and Universities. The largest contingency of Black graduate students was from Hampton University. The program included student research presentations, symposia by MIT faculty and Black physicists. This is a report of the participants in the conference and the topics covered. Also, tours of specific sites are mentioned.
Date: April 6, 2000
Creator: McIntyre, Dr. Cynthia R.
System: The UNT Digital Library
Salinas - An implicit finite element structural dynamics code developed for massively parallel platforms (open access)

Salinas - An implicit finite element structural dynamics code developed for massively parallel platforms

As computational needs for structural finite element analysis increase, a robust implicit structural dynamics code is needed which can handle millions of degrees of freedom in the model and produce results with quick turn around time. A parallel code is needed to avoid limitations of serial platforms. Salinas is an implicit structural dynamics code specifically designed for massively parallel platforms. It computes the structural response of very large complex structures and provides solutions faster than any existing serial machine. This paper gives a current status of Salinas and uses demonstration problems to show Salinas' performance.
Date: April 6, 2000
Creator: BHARDWAJ, MANLJ K.; REESE,GARTH M.; DRIESSEN,BRIAN; ALVIN,KENNETH F. & DAY,DAVID M.
System: The UNT Digital Library
Superlattices of platinum and palladium nanoparticles (open access)

Superlattices of platinum and palladium nanoparticles

The authors have used a nonionic inverse micelle synthesis technique to form nanoclusters of platinum and palladium. These nanoclusters can be rendered hydrophobic or hydrophilic by the appropriate choice of capping ligand. Unlike Au nanoclusters, Pt nanoclusters show great stability with thiol ligands in aqueous media. Alkane thiols, with alkane chains ranging from C{sub 6} to C{sub 18} were used as hydrophobic ligands, and with some of these they were able to form 2-D and/or 3-D superlattices of Pt nanoclusters as small as 2.7 nm in diameter. Image processing techniques were developed to reliably extract from transmission electron micrographs (TEMs) the particle size distribution, and information about the superlattice domains and their boundaries. The latter permits one to compute the intradomain vector pair correlation function of the particle centers, from which they can accurately determine the lattice spacing and the coherent domain size. From these data the gap between the particles in the coherent domains can be determined as a function of the thiol chain length. It is found that as the thiol chain length increases, the gaps between particles within superlattice domains increases, but more slowly than one might expect, possibly indicating thiol chain interdigitation.
Date: April 6, 2000
Creator: Martin, James E.; Wilcoxon, Jess P.; Odinek, Judy G. & Provencio, Paula P.
System: The UNT Digital Library
Thermal chain model of electro- and magnetorheology (open access)

Thermal chain model of electro- and magnetorheology

Steady shear 3-D simulations of electro- and magnetorheology in a uniaxial field are presented. These large scale simulations are three dimensional, and include the effect of Brownian motion. In the absence of thermal fluctuations, the expected shear thinning viscosity is observed in steady shear, and a striped phase is seen to rapidly form in a uniaxial field, with a shear slip zone in each sheet. However, as the influence of Brownian motion increases, the fluid stress decreases, especially at lower Mason numbers, and the striped phase eventually disappears, even when the fluid stress is still high. To account for the uniaxial steady shear data the author proposes a microscopic chain model of the role played by thermal fluctuations on the rheology of ER and MR fluids that delineates the regimes where an applied field can impact the fluid viscosity, and gives an analytical prediction for the thermal effect.
Date: April 6, 2000
Creator: Martin, James E.
System: The UNT Digital Library
Acceleration for a High Energy Muon Collider (open access)

Acceleration for a High Energy Muon Collider

The authors describe a method for designing the acceleration systems for a muon collider, with particular application and examples for a high energy muon collider. This paper primarily concentrates on design considerations coming from longitudinal motion, but some transverse issues are briefly discussed.
Date: April 7, 2000
Creator: Berg, J. S.
System: The UNT Digital Library
Focusing and Acceleration of Bunched Beams (open access)

Focusing and Acceleration of Bunched Beams

A new approach to solving the kinetic equation for the beam distribution function, (very useful from the practical point of view), is discussed, in which the authors also obtain a complement to the Skrinsky's condition for the self-focused bunched beam. This problem belongs to the theory of nonlinear systems in which both regular and chaotic motion is possible. The kinetic approach, based on Vlasov-Poisson equations, are used to investigate the focusing and acceleration of bunched beam. Special attention is given to the studies of stability in a bunched beam by means of the two norm, which may be used to describe t!he motion of high-energy particles.
Date: April 7, 2000
Creator: Parsa, Z. & Zadorozhny, V.
System: The UNT Digital Library
HIGH ENERGY PHYSICS POTENTIAL AT MUON COLLIDERS (open access)

HIGH ENERGY PHYSICS POTENTIAL AT MUON COLLIDERS

In this paper, high energy physics possibilities and future colliders are discussed. The {mu}{sup +} {mu}{sup {minus}} collider and experiments with high intensity muon beams as the stepping phase towards building Higher Energy Muon Colliders (HEMC) are briefly reviewed and encouraged.
Date: April 7, 2000
Creator: Parsa, Z.
System: The UNT Digital Library
Recirculating Acceleration (open access)

Recirculating Acceleration

This paper compares various types of recirculating accelerators, outlining the advantages and disadvantages of various approaches. The accelerators are characterized according to the types of arcs they use: whether there is a single arc for the entire recirculator or there are multiple arcs, and whether the arc(s) are isochronous or non-isochronous.
Date: April 7, 2000
Creator: Berg, J. S.; Garren, A. A. & Johnstone, C.
System: The UNT Digital Library
Risk-Based Management of Contaminated Groundwater: The Role of Geologic Heterogeneity, Exposure and Cancer Risk in Determining the Performance of Aquifer Remediation (open access)

Risk-Based Management of Contaminated Groundwater: The Role of Geologic Heterogeneity, Exposure and Cancer Risk in Determining the Performance of Aquifer Remediation

The effectiveness of aquifer remediation is typically expressed in terms of a reduction in contaminant concentrations relative to a regulated maximum contaminant level (MCL), and is usually confined by sparse monitoring data and/or simple model calculations. Here, the effectiveness of remediation is examined from a risk-based perspective that goes beyond the traditional MCL concept. A methodology is employed to evaluate the health risk to individuals exposed to contaminated household water that is produced from groundwater. This approach explicitly accounts for differences in risk arising from variability in individual physiology and water use, the uncertainty in estimating chemical carcinogenesis for different individuals, and the uncertainties and variability in contaminant concentrations within groundwater. A hypothetical contamination scenario is developed as a case study in a saturated, alluvial aquifer underlying a real Superfund site. A baseline (unremediated) human exposure and health risk scenario, as induced by contaminated groundwater pumped from this site, is predicted and compared with a similar estimate based upon pump-and-treat exposure intervention. The predicted reduction in risk in the remediation scenario is not an equitable one--that is, it is not uniform to all individuals within a population and varies according to the level of uncertainty in prediction. The importance of …
Date: April 7, 2000
Creator: Maxwell, R. M.; Carle, S. F. & Tompson, A. F. B.
System: The UNT Digital Library
Modeling Creep Rupture of Zirconium Alloys (open access)

Modeling Creep Rupture of Zirconium Alloys

Safe interim dry storage of spent nuclear fuel (SNF) must be maintained for a minimum of twenty years according to the Code of Federal Regulations. The most important variable that must be regulated by dry storage licensees in order to meet current safety standards is the temperature of the SNF. The two currently accepted models to define the maximum allowable storage temperature for SNF are based on a diffusion controlled cavity growth (DCCG) failure mechanism for the cladding. Although these models are based on the same fundamental failure theory (DCCG), the researchers who developed the models made different assumptions, including selection of some of the most critical variables in the DCCG failure equation. These inconsistencies are discussed together with recommended modifications to the failure models based on recent data.
Date: April 8, 2000
Creator: Rosen, R.S. & Hayes, T.A.
System: The UNT Digital Library
Recent developments in understanding five-power-law creep in metals (open access)

Recent developments in understanding five-power-law creep in metals

This work describes recent advances on the effects of subgrain boundaries on elevated-temperature plasticity. Particular attention is devoted to recent developments regarding internal back-stresses. This will include discussions of recent convergent beam electron diffraction (CBED) experiments on metals to evaluate internal stresses in association with dislocation heterogeneities.
Date: April 8, 2000
Creator: Kassner, M E; Perez-Prado, M-T; Rosen, R S & Bergsma, S C
System: The UNT Digital Library
Steady State Creep of Zirconium at High and Intermediate Temperatures (open access)

Steady State Creep of Zirconium at High and Intermediate Temperatures

Creep of zirconium and zirconium alloys has been labeled ''anomalous.'' Researchers often report that zirconium and its alloys never reach true steady state creep and have stress exponents that continuously change with stress and temperature. Many varied interpretations have been offered explaining the creep behavior of zirconium. Some have suggested that creep is diffusion controlled, while others maintain that creep is dislocation glide controlled. Cumulative zirconium creep data will be presented based on an extensive literature review. An interpretation of results will be presented and compared to previous interpretations.
Date: April 8, 2000
Creator: Rosen, R.S. & Hayes, T.A.
System: The UNT Digital Library
Engineering Modeling of the Pine Bluff Arsenal Supercritical Water Oxidation Reactor (open access)

Engineering Modeling of the Pine Bluff Arsenal Supercritical Water Oxidation Reactor

None
Date: April 9, 2000
Creator: Rice, Steven F.; Wu, Benjamin C.; Winters, William S. & Robinson, Crane D.
System: The UNT Digital Library
The Advanced Petroleum-Based Fuels Program Evaluation of EC-Diesel and Diesel Particulate Filters in Southern California Vehicle Fleets (open access)

The Advanced Petroleum-Based Fuels Program Evaluation of EC-Diesel and Diesel Particulate Filters in Southern California Vehicle Fleets

The EC-Diesel and particulate filter combination greatly reduced the particulate matter, hydrocarbon, and carbon monoxide emissions of all vehicles tested in the program to date. Particulate matter reductions greater than 98% were achieved. For several vehicles tested, the PM and HC emissions were less than background levels. Based on preliminary statistical analysis, there is 95%+ confidence that EC-D and particulate filters reduced emissions from three different types of vehicles. A fuel consumption penalty was not detectable using the current test procedures and chassis dynamometer laboratory. Test vehicles equipped with the CRT and DPX particulate filters and fueled with EC-Diesel fuel have operated reliably during the program start-up period.
Date: April 10, 2000
Creator: unknown
System: The UNT Digital Library