Resource Type

New Pellet Injection Schemes on DIII-D (open access)

New Pellet Injection Schemes on DIII-D

The pellet fueling system on DIII-D has been modified for injection of deuterium pellets from two vertical ports and two inner wall locations on the magnetic high-field side (HFS) of the tokamak. The HFS pellet injection technique was first employed on ASDEX-Upgrade with significant improvements reported in both pellet penetration and fueling efficiency. The new pellet injection schemes on DIII-D required the installation of new guide tubes. These lines are {approx_equal}12.5 m in total length and are made up of complex bends and turns (''roller coaster'' like) to route pellets from the injector to the plasma, including sections inside the torus. The pellet speed at which intact pellets can survive through the curved guide tubes is limited ({approx_equal}200-300 m/s for HFS injection schemes). Thus, one of the three gas guns on the injector was modified to provide pellets in a lower speed regime than the original guns (normal speed range {approx_equal}500 to 1000 m/s). The guide tube installations and gun modifications are described along with the injector operating parameters, and the latest test results are highlighted.
Date: November 13, 1999
Creator: Anderson, P. M.; Baylor, L. R.; Combs, S. K.; Foust, C. R.; Jernigan, T. C. & Robinson, J. I.
System: The UNT Digital Library
The technical basis for air pathway assessment of resuspended radioactive aerosols: LLNL experiences at seven sites around the world (open access)

The technical basis for air pathway assessment of resuspended radioactive aerosols: LLNL experiences at seven sites around the world

There is a large uncertainty in quantifying the inhalation pathway and the aerosol emission rate in human health assessments of radioactive-contamination sites. The need for site-specific assessments led to formation of our team of specialists at LLNL, who have participated in numerous field campaigns around the world. Our goal was to obtain all the information necessary for determining potential human exposures and to estimate source terms for turbulent transport of the emissions during both normal and disturbed soil conditions. That is, measurements were made of the key variables to quantify the suspended aerosols at the actual contamination sites, but different scenarios for habitation, site management, and site cleanup were included. The most notable locations of these site-investigations were the Marshall Islands (Bikini, Enewetak, and Rongelap), Nevada Test Site (GMX, Little Feller, Palanquin, and Plutonium Valley), Tonopah (Nevada--site of Roller Coaster), Savannah River Lab (South Carolina--H-Area site), Johnston Island (cleanup of rocket-impact site), Chernobyl (Ukraine--grass field end sandy beach sites near Nuclear Power Plant Unit 4), and Palomares (Spain--site of aircraft accident). This discussion will review the variables quantified, methods developed, general results, uncertainty of estimations, and recommendations for future research that are a result of our experience in these field …
Date: September 1, 1993
Creator: Shinn, J. H.
System: The UNT Digital Library
Proceedings of the opportunities in the synfuels industry (open access)

Proceedings of the opportunities in the synfuels industry

World interest in coal-based synthetic fuels technology is like a roller coaster ride. Interest soars when energy prices are high or world oil supplies are threatened. When energy is inexpensive and oil is plentiful, interest plummets. However, some people remain undaunted by the ups and downs of the synfuels industry. They cling tenaciously to the idea that coal-based synthetic fuels are the world`s energy future. They are the select group attending the SynOps `92 symposium in Bismarck, North Dakota. SynOps `92 participants represent an extraordinary combination of visionaries and practical thinkers. They believe the ``coal refinery`` concept will eventually provide the most efficient and productive use of our coal resources. They know that coal is a valuable resource which can be used to produce a huge variety of valuable nonfuel products. They also recognize that until technology can make alternative fuels economically feasible, the world will continue to rely heavily on fossil fuels--especially coal, the world`s most abundant energy resource. Individual papers have been entered.
Date: December 31, 1992
Creator: unknown
System: The UNT Digital Library
Sensitivity of numerical dispersion modeling to explosive source parameters (open access)

Sensitivity of numerical dispersion modeling to explosive source parameters

The calculation of downwind concentrations from non-traditional sources, such as explosions, provides unique challenges to dispersion models. The US Department of Energy has assigned the Atmospheric Release Advisory Capability (ARAC) at the Lawrence Livermore National Laboratory (LLNL) the task of estimating the impact of accidental radiological releases to the atmosphere anywhere in the world. Our experience includes responses to over 25 incidents in the past 16 years, and about 150 exercises a year. Examples of responses to explosive accidents include the 1980 Titan 2 missile fuel explosion near Damascus, Arkansas and the hydrogen gas explosion in the 1986 Chernobyl nuclear power plant accident. Based on judgment and experience, we frequently estimate the source geometry and the amount of toxic material aerosolized as well as its particle size distribution. To expedite our real-time response, we developed some automated algorithms and default assumptions about several potential sources. It is useful to know how well these algorithms perform against real-world measurements and how sensitive our dispersion model is to the potential range of input values. In this paper we present the algorithms we use to simulate explosive events, compare these methods with limited field data measurements, and analyze their sensitivity to input parameters. …
Date: February 13, 1991
Creator: Baskett, R.L. (EG and G Energy Measurements, Inc., Pleasanton, CA (USA)) & Cederwall, R.T. (Lawrence Livermore National Lab., CA (USA))
System: The UNT Digital Library
Evaluation of the Atmospheric Release Advisory Capability emergency response model for explosive sources (open access)

Evaluation of the Atmospheric Release Advisory Capability emergency response model for explosive sources

The Atmospheric Release Advisory Capability (ARAC) at the Lawrence Livermore National Laboratory (LLNL) uses a modeling system to calculate the impact of accidental radiological or toxic releases to the atmosphere anywhere in the world. Operated for the US Departments of Energy and Defense, ARAC has responded to over 60 incidents in the past 18 years, and conducts over 100 exercises each year. Explosions are one of the most common mechanisms by which toxic particulates are injected into the atmosphere during accidents. Automated algorithms with default assumptions have been developed to estimate the source geometry and the amount of toxic material aerosolized. The paper examines the sensitivity of ARAC`s dispersion model to the range of input values for explosive sources, and analyzes the model`s accuracy using two field measurement programs.
Date: October 7, 1993
Creator: Baskett, R. L.; Freis, R. P. & Nasstrom, J. S.
System: The UNT Digital Library
Springlake Park: An Oklahoma City Playground Remembered (open access)

Springlake Park: An Oklahoma City Playground Remembered

Article explores the establishment of Springlake Park in Oklahoma City, the owners who ran it, and its eventual downfall. William C. Boone examines the activities that kept the park booming and the reasons for its closing.
Date: Spring 1991
Creator: Boone, William C.
System: The Gateway to Oklahoma History
An updated summary of MATHEW/ADPIC model evaluation studies (open access)

An updated summary of MATHEW/ADPIC model evaluation studies

This paper summarizes the major model evaluation studies conducted for the MATHEW/ADPIC atmospheric transport and diffusion models used by the US Department of Energy's Atmospheric Release Advisory Capability. These studies have taken place over the last 15 years and involve field tracer releases influenced by a variety of meteorological and topographical conditions. Neutrally buoyant tracers released both as surface and elevated point sources, as well as material dispersed by explosive, thermally bouyant release mechanisms have been studied. Results from these studies show that the MATHEW/ADPIC models estimate the tracer air concentrations to within a factor of two of the measured values 20% to 50% of the time, and within a factor of five of the measurements 35% to 85% of the time depending on the complexity of the meteorology and terrain, and the release height of the tracer. Comparisons of model estimates to peak downwind deposition and air concentration measurements from explosive releases are shown to be generally within a factor of two to three. 24 refs., 14 figs., 3 tabs.
Date: May 1, 1990
Creator: Foster, Kevin T. & Dickerson, Marvin H.
System: The UNT Digital Library
Advances in technology transfer at Federal Facilities (open access)

Advances in technology transfer at Federal Facilities

The Hanford Site, located in the southeast portion of the state of Washington, is a 1450-hectare (560 square miles) reservation that was selected by the US Government in 1942 for production of the world`s first nuclear weapons materials. For more than 40 years, defense production operations at Hanford generated hazardous and radioactive materials and wastes that for the most part remain there today. Environmental restoration of the Hanford Site is the primary mission of the Westinghouse Hanford Company (WHC) and it is also the thrust of the Tri-Party agreement among the US Environmental Protection Agency, the Washington State Department of Ecology and the US Department of Energy. Restoration will require treatment of about 1400 individual locations that are contaminated by chemically hazardous wastes, radioactive wastes, non-hazardous wastes and mixed hazardous and radioactive wastes. These locations include burial sites, storage facilities, obsolete buildings, settling ponds, waste cribs and large and small areas of near-surface and deep soil contamination. Burial trenches contain an estimated 109,000 cubic meters of low-level solid wastes contaminated with hazardous chemicals and radioactive materials. Approximately 450 sites were contaminated by discharge of liquids to the ground and there are about 250 additional areas where waste materials were spilled. …
Date: November 1, 1994
Creator: Silva, R. R. Jr.
System: The UNT Digital Library
Remedial Actions of Nuclear Safety Shot Sites: Double Tracks and Clean Slates (open access)

Remedial Actions of Nuclear Safety Shot Sites: Double Tracks and Clean Slates

Remedial actions of plutonium (Pu)-contaminated soils are in the preliminary stages of development at the Nevada Test Site (NTS). Interim clean-up actions were completed at the Double Tracks and Clean Slate 1 safety shot sites in 1996 and 1997, respectively. Soil at both sites, with a total transuranic activity greater than 20 picoCuries per gram (pCi/g), was excavated and shipped to the NTS for disposal. Characterization and assessment efforts were initiated at the Double Tracks site in 1995, and the clean-up of this site as an interim action was completed in 1996. Clean-up of this site consisted of taking site-specific data and applying rationale for dose and risk calculations in selecting parameter values for the interim corrective action level. The remediation process included excavating and stockpiling the contaminated soil and loading the soil into supersacks with approximately 1,513 cubic meters (53,500 cubic feet) being shipped to the NTS for disposal. In 1997, remediation began on the Clean Slate 1 site on which characterization had already been completed using a very similar approach; however, the site incorporated lessons learned, cost efficiencies, and significant improvements to the process. This paper focuses on those factors and the progress that has been made in …
Date: March 1, 1998
Creator: Sanchez, M.; Shotton, M. & Lyons, C.
System: The UNT Digital Library
1972-1997, Twenty-five years of energy and environmental history : lessons learned. (open access)

1972-1997, Twenty-five years of energy and environmental history : lessons learned.

Given the events of the past 25 years concerning energy and environmental issues and our reaction to them, what lessons can we learn? First, the individual American consumer wants and expects energy to be a stable commodity with low prices and easy availability. As evidenced by the heated debate over increasing the federal gasoline tax by $.05 per gallon (which would still leave Americans paying only one-third of what Europeans pay for gasoline), increases in energy prices elicit very strong public and political opposition. As further evidence, it has been argued that the general public support of the Gulf War was due, in part, to a recognition of the need to maintain a stable source of cheap oil from the region. The American public wants to maintain the benefits of cheap and abundant energy and expects its political leaders to make it happen. A second lesson is that if constraints on the energy supply do occur (e.g., the OPEC-imposed oil embargo) ardor environmental impacts from energy use do appear to be significant (e.g., SO{sub 2} and CO{sub 2} emissions), the preference is for a technology fix rather than a behavioral change. This is evidenced by our reliance on moving low-sulfur …
Date: December 17, 1997
Creator: Drucker, H.
System: The UNT Digital Library
Basis for the power supply reliability study of the 1 MW neutron source (open access)

Basis for the power supply reliability study of the 1 MW neutron source

The Intense Pulsed Neutron Source (IPNS) upgrade to 1 MW requires new power supply designs. This paper describes the tools and the methodology needed to assess the reliability of the power supplies. Both the design and operation of the power supplies in the synchrotron will be taken into account. To develop a reliability budget, the experiments to be conducted with this accelerator are reviewed, and data is collected on the number and duration of interruptions possible before an experiment is required to start over. Once the budget is established, several accelerators of this type will be examined. The budget is allocated to the different accelerator systems based on their operating experience. The accelerator data is usually in terms of machine availability and system down time. It takes into account mean time to failure (MTTF), time to diagnose, time to repair or replace the failed components, and time to get the machine back online. These estimated times are used as baselines for the design. Even though we are in the early stage of design, available data can be analyzed to estimate the MTTF for the power supplies.
Date: July 1, 1993
Creator: McGhee, D. G. & Fathizadeh, M.
System: The UNT Digital Library
Projected Consequence for Potential Sabotage Events Related to Spent Fuel Shipments (open access)

Projected Consequence for Potential Sabotage Events Related to Spent Fuel Shipments

There is a growing interest in understanding the potential consequences of malevolent acts against shipments of nuclear waste and/or material. Recently, Sandia National Laboratories (SNL) conducted a study' to evaluate the potential source terms available for release in a sabotage event for spent fuel shipments. Using these source terms, we developed an approach to assess the potential radiological consequences of the hypothesized events and to compare them to consequences of transportation accidents involving the same types of shipments. Our analysis showed that there could be orders of magnitude differences in consequence for urban, suburban, and rural events. Sabotage consequences could be orders of magnitude higher than those of transportation accidents with a probability of 10{sup {minus}12} or higher and be similar to events with a probability less than 10{sup {minus}12}. Also, explosive-induced buoyancy would disperse the source further out than a non-buoyant release in a transportation accident, which, therefore, would have a higher dose near the release point.
Date: August 18, 1999
Creator: Shyr, Lih-Jenn; Neuhauser, Sieglinde; Mills, Scott & Massey, Charles
System: The UNT Digital Library
Expanding Grof's Concept of the Perinatal: Deepening the Inquiry into Frightening Near-Death Experiences (open access)

Expanding Grof's Concept of the Perinatal: Deepening the Inquiry into Frightening Near-Death Experiences

Study suggesting that in order to explain the phenomenology of perinatal experience, as described in the work of Stanislav Grof, we must hypothesize that the patient in these instances has expanded beyond the individual subject.
Date: Winter 1996
Creator: Bache, Christopher M.
System: The UNT Digital Library
Materials and superconducting electronics (open access)

Materials and superconducting electronics

This report consists of a dialog by Dr. James L. Smith at the Superconducting Digital Circuits and Systems Conference. (JL)
Date: January 1, 1991
Creator: Smith, J.L.
System: The UNT Digital Library
Photodisintegration of the deuteron at high energy (open access)

Photodisintegration of the deuteron at high energy

Measurements of the angular distribution for the {gamma}d{yields}+pn reaction were performed at SLAC for photon energies between 0.7 and 1.8 GeV (experiment NE8) and between 1.6 and 4.4. GeV (experiment NE17). The final results for experiment NE8 will be presented, but only preliminary results for NE17 will be discussed. The data at {theta}{sub cm} = 90{degrees} appear to follow the constituent counting rules. The angular distribution at high photon energies exhibit large values of the cross section at forward angles. There is evidence that the cross section may also be large at backward angles and high energies.
Date: January 1, 1992
Creator: Holt, R. J.
System: The UNT Digital Library
The design and implementation of an operational model evaluation system. Revision 1 (open access)

The design and implementation of an operational model evaluation system. Revision 1

The complete evaluation of an atmospheric transport and diffusion model typically includes a study of the model`s operational performance. Such a study very often attempts to compare the model`s calculations of an atmospheric pollutant`s temporal and spatial distribution with field experiment measurements. However, these comparisons tend to use data from a small number of experiments and are very often limited to producing the commonly quoted statistics based on the differences between model calculations and the experimental measurements (fractional bias, fractional scatter, etc.). This paper presents initial efforts to develop a model evaluation system geared for both the objective statistical analysis and the subjective visualization of the interrelationships between a model`s calculations and the appropriate field measurement data.
Date: June 1, 1995
Creator: Foster, K. T.
System: The UNT Digital Library
The Hanford Summit and Sustainable Development (open access)

The Hanford Summit and Sustainable Development

Since the days of the Manhattan Project of World War II, the economic well being of the Tri-Cities (Pasco, Kennewick, and Richland) of Washington State has been tied to the US Department of Energy missions at the nearby Hanford Site. As missions at the Site changed, so did the well being of the region. The Hanford Site is now poised to complete its final mission, that of environmental restoration. When restoration is compiled, the Site may be closed and the effect on the local economy will be devastating if action is not taken now. To that end, economic diversification and transition are being planned. To facilitate the process, the Hanford Site will become a sustainable development demonstration project -- a project with regional, national, and international application.
Date: May 1, 1994
Creator: Sullivan, C. T.
System: The UNT Digital Library
Manufacturing diamond films using copper vapour lasers (open access)

Manufacturing diamond films using copper vapour lasers

Fifty nanosecond pulses of visible light have been used to produce hard, hydrogen-free diamond-like-carbon (DLC) films at irradiances between 5 x 10{sup 8} and 5 x 10{sup 10} W/cm{sup 2} The films were characterized by a number of techniques including: Raman spectroscopy, Electron Energy Loss Spectroscopy (EELS), atomic force microscopy, and spectroscopic ellipsometry. The cost for manufacturing DLC with high average power, high-pulse repetition frequency, visible light is low enough to compete with other diamond thin film production methods.
Date: January 8, 1996
Creator: McLean, M., LLNL
System: The UNT Digital Library
Polymerization of bis(triethoxysilyl)ethenes. The impact of substitution geometry on the formation of ethenyl- and vinylidene-bridged polysilsesquioxanes (open access)

Polymerization of bis(triethoxysilyl)ethenes. The impact of substitution geometry on the formation of ethenyl- and vinylidene-bridged polysilsesquioxanes

Preparation of organically-bridged polysilsesquioxanes has been achieved by polymerizing organic monomers with two or more trialkoxysilyl groups per monomer repeat unit. The nature of the organic bridging group has been shown to strongly impact the final properties (surface area, pore size, and thermal stability) of the end product. For example, rigid arylene bridging groups have been shown to give rise to materials with high surface areas with a relatively large contribution from micropores (< 20 {angstrom}). The length of alkylene-bridging groups can be used to control the size and dispersity of pores in hydrocarbon-bridged xerogels. In this study, the authors have examined the preparation of ethylene-bridged polysilsesquioxanes from the E-(1) and Z-(2) isomers of 1,2-bis(triethoxysilyl)ethene and vinylidene-bridged polysilsesquioxanes from 1,1-bis(triethoxysilyl)ethene-(3). This study was intended to determine the effects of substitution geometry about the carbon-carbon double bond on the condensation chemistry of the monomers and on the resulting architectures of the final materials.
Date: July 1, 1998
Creator: Carpenter, J. P.; Yamanaka, S. A.; McClain, M. D.; Loy, D. A.; Greaves, J. & Shea, K. J.
System: The UNT Digital Library
Hanford Site sustainable development initiatives (open access)

Hanford Site sustainable development initiatives

Since the days of the Manhattan Project of World War II, the economic well being of the Tri-Cities (Pasco, Kennewick, and Richland) of Washington State has been tied to the US Department of Energy missions at the nearby Hanford Site. As missions at the Site changed, so did the economic vitality of the region. The Hanford Site is now poised to complete its final mission, that of environmental restoration. When restoration is completed, the Site may be closed and the effect on the local economy will be devastating if action is not taken now. To that end, economic diversification and transition are being planned. To facilitate the process, the Hanford Site will become a sustainable development demonstration project.
Date: May 1, 1994
Creator: Sullivan, C. T.
System: The UNT Digital Library
Parallel Simulation of Three-Dimensional Free Surface Fluid Flow Problems (open access)

Parallel Simulation of Three-Dimensional Free Surface Fluid Flow Problems

Simulation of viscous three-dimensional fluid flow typically involves a large number of unknowns. When free surfaces are included, the number of unknowns increases dramatically. Consequently, this class of problem is an obvious application of parallel high performance computing. We describe parallel computation of viscous, incompressible, free surface, Newtonian fluid flow problems that include dynamic contact fines. The Galerkin finite element method was used to discretize the fully-coupled governing conservation equations and a ''pseudo-solid'' mesh mapping approach was used to determine the shape of the free surface. In this approach, the finite element mesh is allowed to deform to satisfy quasi-static solid mechanics equations subject to geometric or kinematic constraints on the boundaries. As a result, nodal displacements must be included in the set of unknowns. Other issues discussed are the proper constraints appearing along the dynamic contact line in three dimensions. Issues affecting efficient parallel simulations include problem decomposition to equally distribute computational work among a SPMD computer and determination of robust, scalable preconditioners for the distributed matrix systems that must be solved. Solution continuation strategies important for serial simulations have an enhanced relevance in a parallel coquting environment due to the difficulty of solving large scale systems. Parallel computations …
Date: October 14, 1999
Creator: Baer, Thomas A.; Subia, Samuel R. & Sackinger, Philip A.
System: The UNT Digital Library
Role of nuclear binding in the EMC effect (open access)

Role of nuclear binding in the EMC effect

We present a new derivation of the convolution formula for the contributions of nuclear binding to the structure functions measured in the deep inelastic scattering of leptons from nuclei. The derivation, which is manifestly covariant, gives a new binding correction. This new correction, which depends on the mass of the recoiling nucleon fragments, gives corrections that are numerically significant, and that improve the agreement between theory and experiment at large x. We conclude that nuclear binding effects may be sufficient to explain the European-Muon-Collaboration effect at large x.
Date: October 1, 1991
Creator: Gross, Franz & Gross, Franz
System: The UNT Digital Library
A brief history in time of ion traps and their achievements in science (open access)

A brief history in time of ion traps and their achievements in science

None
Date: November 1, 1994
Creator: Holzscheiter, M. H.
System: The UNT Digital Library
Ninth target fabrication specialists` meeting: Proceedings (open access)

Ninth target fabrication specialists` meeting: Proceedings

This report contains a collection of viewgraphs and short papers on target fabrication for inertial confinement purposes.
Date: December 31, 1993
Creator: unknown
System: The UNT Digital Library