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Motion Planning for a Direct Metal Deposition Rapid Prototyping System (open access)

Motion Planning for a Direct Metal Deposition Rapid Prototyping System

A motion planning strategy was developed and implemented to generate motion control instructions from solid model data for controlling a robotically driven solid free-form fabrication process. The planning strategy was tested using a PUMA type robot arm integrated into a LENS{trademark} (Laser Engineered Net Shape) system. Previous systems relied on a series of x, y, and z stages, to provide a minimal coordinated motion control capability. This limited the complexity of geometries that could be constructed. With the coordinated motion provided by a robotic arm, the system can produce three dimensional parts by ''writing'' material onto any face of existing material. The motion planning strategy relied on solid model geometry evaluation and exploited robotic positioning flexibility to allow the construction of geometrically complex parts. The integration of the robotic manipulator into the LENS{trademark} system was tested by producing metal parts directly from CAD models.
Date: October 18, 1999
Creator: AMES,ARLO L.; HENSINGER,DAVID M. & KUHLMANN,JOEL L.
Object Type: Article
System: The UNT Digital Library
DESIGN AND ANALYSIS OF THE SNS CCL HOT MODEL WATER COOLING SYSTEM USING THE SINDA/FLUINT NETWORK MODELING TOOL (open access)

DESIGN AND ANALYSIS OF THE SNS CCL HOT MODEL WATER COOLING SYSTEM USING THE SINDA/FLUINT NETWORK MODELING TOOL

This report presents results for design and analysis of the hot model water cooling system for the Spallation Neutron Source (SNS) coupled-cavity linac (CCL). The hot model, when completed, will include segments for both the CCL and coupled-cavity drift-tube linac (CCDTL). The scope of this report encompasses the modeling effort for the CCL portion of the hot model. This modeling effort employed the SINDA/FLUINT network modeling tool. This report begins with an introduction of the SNS hot model and network modeling using SINDA/FLUINT. Next, the development and operation of the SINDA/FLUINT model are discussed. Finally, the results of the SINDA/FLUINT modeling effort are presented and discussed.
Date: November 1, 1999
Creator: AMMERMAN, C. & BERNARDIN, J.
Object Type: Report
System: The UNT Digital Library
Evaluation of cracking in the 241-AZ tank farm ventilation line at the Hanford Site (open access)

Evaluation of cracking in the 241-AZ tank farm ventilation line at the Hanford Site

In the period from April to October of 1988, a series of welding operations on the outside of the AZ Tank Farm ventilation line piping at the Hanford Site produced unexpected and repeated cracking of the austenitic stainless steel base metal and of a seam weld in the pipe. The ventilation line is fabricated from type 304L stainless steel pipe of 24 inch diameter and 0.25 inch wall thickness. The pipe was wrapped in polyethylene bubble wrap and buried approximately 12 feet below grade. Except for the time period between 1980 and 1987, impressed current cathodic protection has been applied to the pipe since its installation in 1974. The paper describes the history of the cracking of the pipe, the probable cracking mechanisms, and the recommended future action for repair/replacement of the pipe.
Date: October 20, 1999
Creator: ANANTATMULA, R.P.
Object Type: Article
System: The UNT Digital Library
Corrosion of Uranium in Desert Soil, with Application to GCD Source Term M (open access)

Corrosion of Uranium in Desert Soil, with Application to GCD Source Term M

Uranium fragments from the Sandia Sled Track were studied as analogues for weapons components and depleted uranium buried at the Greater Confinement Disposal (GCD) site in Nevada. The Sled Track uranium fragments originated as weapons mockups and counterweights impacted on concrete and soil barriers, and experienced heating and fragmentation similar to processes thought to affect the Nuclear Weapons Accident Residues (NWAR) at GCD. Furthermore, the Sandia uranium was buried in unsaturated desert soils for 10 to 40 years, and has undergone weathering processes expected to affect the GCD wastes. Scanning electron microscopy, X-ray diffraction and microprobe analyses of the fragments show rapid alteration from metals to dominantly VI-valent oxy-hydroxides. Leaching studies of the samples give results consistent with published U-oxide dissolution rates, and suggest longer experimental periods (ca. 1 year) would be required to reach equilibrium solution concentrations. Thermochemical modeling with the EQ3/6 code indicates that the uranium concentrations in solutions saturated with becquerelite could increase as the pore waters evaporate, due to changes in carbonate equilibria and increased ionic strength.
Date: September 1, 1999
Creator: ANDERSON, HOWARD L.; BACA, JULIANNE; KRUMHANSL, JAMES L.; STOCKMAN, HARLAN W. & THOMPSON, MOLLIE E.
Object Type: Report
System: The UNT Digital Library
STATUS OF THE ACCELERATOR PRODUCTION OF TRITIUM (APT) PROJECT (open access)

STATUS OF THE ACCELERATOR PRODUCTION OF TRITIUM (APT) PROJECT

None
Date: November 1, 1999
Creator: ANDERSON, J. L.; LISOWSKI, P. W. & AL, ET
Object Type: Article
System: The UNT Digital Library
Plutonium reclamation facility (PRF), building 236-Z layup plan (open access)

Plutonium reclamation facility (PRF), building 236-Z layup plan

This document reviews each system inside PRF to determine the operation and maintenance requirements necessary to maintain safe and predictable system performance for facility systems needed to remain operational while minimizing the maintenance and surveillance being performed. Also covered are the actions required to place PRF in a safe layup configuration while minimizing hazards and taking into account the need for reactivation of certain equipment when cleanup work commences in the future.
Date: April 6, 1999
Creator: ANDERSON, R.N.
Object Type: Report
System: The UNT Digital Library
Evaluation of the Cask Transportation Facility Modifications (CTFM) compliance to DOE order 6430.1A (open access)

Evaluation of the Cask Transportation Facility Modifications (CTFM) compliance to DOE order 6430.1A

This report was prepared to evaluate the compliance of Cask Transportation Facility Modifications (CTFM) to DOE Order 6430.1A.
Date: July 14, 1999
Creator: ARD, K.E.
Object Type: Report
System: The UNT Digital Library
DEVELOPMENT OF REMOTE MONITORING SYSTEM FOR THE UNATTENDED MODE NDA IN PFPF (open access)

DEVELOPMENT OF REMOTE MONITORING SYSTEM FOR THE UNATTENDED MODE NDA IN PFPF

None
Date: November 1, 1999
Creator: ASAKURA, K.; OHTANI, T. & AL, ET
Object Type: Article
System: The UNT Digital Library
Bipolaron Hopping Conduction in Boron Carbides (open access)

Bipolaron Hopping Conduction in Boron Carbides

The electrical conductivities of boron carbides, B{sub 12+x}C{sub 3{minus}x} with 0.1 < x < 1.7, between 300 and 1200K suggest the hopping of a nearly temperature-independent density of small (bi)polarons. The activation energies of the nobilities are low, {approx} 0.16 eV, and are nearly independent of the composition. At lower temperatures, conductivities have non-Arrhenius temperature dependencies and strong sensitivity to carbon concentration. Percolative aspects of low-temperature hopping are evident in this sensitivity to composition. Boron carbides' Seebeck coefficients are anomalous in that (1) they are much larger than expected from boron carbides' large carrier densities and (2) they depend only weakly on the carrier density. Carrier-induced softening of local vibrations gives contributions to the Seebeck coefficient that mirror the magnitudes and temperature dependencies found in boron carbides.
Date: September 20, 1999
Creator: ASELAGE, TERRENCE L.; EMIN, D. & MCCREADY, STEVEN S.
Object Type: Article
System: The UNT Digital Library
MIL-L-87177 and CLT:X-10 Lubricants Improve Electrical Connector Fretting Corrosion Behavior (open access)

MIL-L-87177 and CLT:X-10 Lubricants Improve Electrical Connector Fretting Corrosion Behavior

We have conducted a fretting research project using MIL-L-87177 and CLT: X-10 lubricants on Nano-miniature connectors. When they were fretted without lubricant, individual connectors first exceeded our 0.5 ohm failure criteria from 2,341 to 45,238 fretting cycles. With additional fretting, their contact resistance increased to more than 100,000 ohms. Unmodified MIL-L-87177 lubricant delayed the onset of first failure to between 430,000 and over 20,000,000 fretting cycles. MIL-L-87177 modified by addition of Teflon powder delayed first failure to beyond 5 million fretting cycles. Best results were obtained when Teflon was used and also when both the straight and modified lubricants were poured into and then out of the connector. CLT: X-10 lubricant delayed the onset of first failure to beyond 55 million cycles in one test where a failure was actually observed and to beyond 20 million cycles in another that was terminated without failure. CLT: X-10 recovered an unlubricated connector driven deeply into failure, with six failed pins recovering immediately and four more recovering during an additional 420 thousand fretting cycles. MIL-L-87177 was not able to recover a connector under similar conditions.
Date: October 12, 1999
Creator: AUKLAND,NEIL R. & HANLON,JAMES T.
Object Type: Article
System: The UNT Digital Library
Dose commitments due to radioactive releases from nuclear power plant sites in 1992. Volume 14 (open access)

Dose commitments due to radioactive releases from nuclear power plant sites in 1992. Volume 14

Population and individual radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1992. Fifty-year dose commitments for a 1-year exposure from both liquid and atmospheric releases were calculated for four population groups (infant, child, teenager, and adult) residing between 2 and 80 km from each of 72 reactor sites. This report tabulates the results of these calculations, showing the dose commitments for both water and airborne pathways for each age group and organ. Also included for each of the sites is an estimate of individual doses, which are compared with 10 CFR Part 50, Appendix I, design objectives. The total collective dose commitments (from both liquid and airborne pathways) for each site ranged from a high of 3.7 person-rem to a low of 0.0015 person-rem for the sites with plants in operation and producing power during the year. The arithmetic mean was 0.66 person-rem. The total population dose for all sites was estimated at 47 person-rem for the 130-million people considered at risk. The individual dose commitments estimated for all sites were below the 10 CFR 50, Appendix I, design objectives.
Date: March 1, 1996
Creator: Aaberg, R. L. & Baker, D. A.
Object Type: Report
System: The UNT Digital Library
Definition of Intrusion Scenarios and Example Concentration Ranges for the Disposal of Near-Surface Waste at the Hanford Site (open access)

Definition of Intrusion Scenarios and Example Concentration Ranges for the Disposal of Near-Surface Waste at the Hanford Site

The US Department of Energy (DOE) is in the process of conducting performance assessments of its radioactive waste sites and disposal systems to ensure that public health and safety are protected, the environment is preserved, and that no remedial actions after disposal are required. Hanford Site low-level waste performance assessments are technical evaluations of waste sites or disposal systems that provide a basis for making decisions using established criteria. The purpose of this document is to provide a family of scenarios to be considered when calculating radionuclide exposure to individuals who may inadvertently intrude into near-surface waste disposal sites. Specific performance assessments will use modifications of the general scenarios described here to include additional site/system details concerning the engineering design, waste form, inventory, and environmental setting. This document also describes and example application of the Hanford-specific scenarios in the development of example concentration ranges for the disposal of near-surface wastes. The overall goal of the example calculations is to illustrate the application of the scenarios in a performance assessment to assure that people in the future cannot receive a dose greater than an established limit. 24 refs., 2 figs., 5 tabs.
Date: October 1990
Creator: Aaberg, R. L. & Kennedy, W. E., Jr.
Object Type: Report
System: The UNT Digital Library
Radiation dose assessment methodology and preliminary dose estimates to support US Department of Energy radiation control criteria for regulated treatment and disposal of hazardous wastes and materials (open access)

Radiation dose assessment methodology and preliminary dose estimates to support US Department of Energy radiation control criteria for regulated treatment and disposal of hazardous wastes and materials

This report provides unit dose to concentration levels that may be used to develop control criteria for radionuclide activity in hazardous waste; if implemented, these criteria would be developed to provide an adequate level of public and worker health protection, for wastes regulated under U.S, Environmental Protection Agency (EPA) requirements (as derived from the Resource Conservation and Recovery Act [RCRA] and/or the Toxic Substances Control Act [TSCA]). Thus, DOE and the US Nuclear Regulatory Commission can fulfill their obligation to protect the public from radiation by ensuring that such wastes are appropriately managed, while simultaneously reducing the current level of dual regulation. In terms of health protection, dual regulation of very small quantities of radionuclides provides no benefit.
Date: July 1, 1995
Creator: Aaberg, R. L.; Baker, D. A.; Rhoads, K.; Jarvis, M. F. & Kennedy, W. E. Jr.
Object Type: Report
System: The UNT Digital Library
The comparison of element partitioning in two types of thermal treatment facilities and the effects on potential radiation dose (open access)

The comparison of element partitioning in two types of thermal treatment facilities and the effects on potential radiation dose

The US Department of Energy (DOE) is performing a technical analysis to support the potential development of risk-based, numerical radiological control criteria (RCC) for mixed waste from DOE operations. As part of the technical analysis, potential future radiation doses are being calculated for workers at thermal treatment facilities and members of the public residing near such facilities. This study compared two types of thermal treatment systems: a conventional combustion chamber with excess air, represented by a rotary kiln with afterburner, and an oxygen-deficient pyrolysis unit, represented by a plasma arc furnace. The purpose of the first part of this study is to estimate the partitioning for significant radionuclides and elements in the two types of thermal treatment systems. Excess-air systems are generally found to produce heavy-metal chlorides, oxides, and sulfates; plasma-arc systems tend to produce more volatile free metals. This difference causes a change in source term dominance from halide volatility to free metal volatility. Chemical thermodynamic methodology is used to estimate partitioning in the two treatment systems. The second part of the study examines how the potential radiation dose to workers handling residue materials is affected by partitioning of radionuclides at the different types of facilities.
Date: May 1, 1995
Creator: Aaberg, R. L.; Burger, L. L.; Baker, D. A.; Wallo, A., III; Vazquez, G. A. & Beck, W. L.
Object Type: Report
System: The UNT Digital Library
Hydrogeologic characterization of the cretaceous-tertiary Coastal Plain sequence at the Savannah River Site (open access)

Hydrogeologic characterization of the cretaceous-tertiary Coastal Plain sequence at the Savannah River Site

Several hydrostratigraphic classification schemes have been devised to describe the hydrogeology at the Savannah River Site SRS. Central to these schemes is the one-to-one fixed relationship between the hydrostratigraphic units and the lithostratigraphic units currently favored for the Site. This fixed relationship has proven difficult to apply in studies of widely separated locations at the Site due to the various facies observed in the updip Coastal Plain sequence. A detailed analysis and synthesis of the geophysical, core, and hydrologic data available from more than 164 deep wells from 23 cluster locations both on the Site and in the surrounding region was conducted to provide the basis for a hydrostratigraphic classification scheme which could be applied to the entire SRS region. As a result, an interim hydrostratigraphic classification was developed that defines the regional hydrogeologic characteristics of the aquifers underlying the Site (Aadland et al., 1990). The hydrostratigraphic code accounts for and accommodates the rapid lateral variation in lithofacies observed in the region, and eliminates all formal'' connection between the hydrostratigraphic nomenclature and the lithostratigraphic nomenclature. The code is robust and can be made as detailed as is needed to characterize the aquifer units and aquifer zones described in Site-specific studies. …
Date: January 1, 1990
Creator: Aadland, R. K.
Object Type: Article
System: The UNT Digital Library
Classification of hydrostratigraphic units at the Savannah River Site, South Carolina (open access)

Classification of hydrostratigraphic units at the Savannah River Site, South Carolina

A detailed synthesis of the hydrologic, geophysical and core data from wells penetrating the updip Mesozoic-Cenozoic Coastal Plain sequence at and near the Savannah River Site (SRS) was conducted to define and classify the hydrostratigraphic units. The purpose of the study was to give the SRS a single unified hydrostratigraphic classification that defines and addresses the hydrogeologic characteristics of the aquifers underlying the site. The characterization, areal distribution and classification of the aquifer and aquifer systems gives SRS the tools to evaluate ground water movement and contaminant transport in a comprehensive regional context. An alpha-numeric nomenclature has been temporarily adopted in this report for classifying the aquifers and aquifer systems at SRS. Formal geographic names for the aquifers and aquifer systems will be proposed in the near future but must be agreed upon and ratified by the South Carolina Hydrostratigraphic Subcommittee which was in part organized for the purpose. The classification utilizes a hierarchy of terms ranked at three levels: Aquifer Systems that transmit ground water regionally; Aquifer Units which are mappable units > 400 square miles in area; and Aquifer Zones that differentiate aquifers internally on the basis of locally significant characteristics.
Date: December 1, 1990
Creator: Aadland, R. K. & Bledsoe, H. W.
Object Type: Report
System: The UNT Digital Library
Classification of hydrostratigraphic units at the Savannah River Site, South Carolina (open access)

Classification of hydrostratigraphic units at the Savannah River Site, South Carolina

A detailed synthesis of the hydrologic, geophysical and core data from wells penetrating the updip Mesozoic-Cenozoic Coastal Plain sequence at and near the Savannah River Site (SRS) was conducted to define and classify the hydrostratigraphic units. The purpose of the study was to give the SRS a single unified hydrostratigraphic classification that defines and addresses the hydrogeologic characteristics of the aquifers underlying the site. The characterization, areal distribution and classification of the aquifer and aquifer systems gives SRS the tools to evaluate ground water movement and contaminant transport in a comprehensive regional context. An alpha-numeric nomenclature has been temporarily adopted in this report for classifying the aquifers and aquifer systems at SRS. Formal geographic names for the aquifers and aquifer systems will be proposed in the near future but must be agreed upon and ratified by the South Carolina Hydrostratigraphic Subcommittee which was in part organized for the purpose. The classification utilizes a hierarchy of terms ranked at three levels: Aquifer Systems that transmit ground water regionally; Aquifer Units which are mappable units > 400 square miles in area; and Aquifer Zones that differentiate aquifers internally on the basis of locally significant characteristics.
Date: December 1, 1990
Creator: Aadland, R. K. & Bledsoe, H. W.
Object Type: Report
System: The UNT Digital Library
Hydrostratigraphy of the General Separations Area, Savannah River Site (SRS), South Carolina (open access)

Hydrostratigraphy of the General Separations Area, Savannah River Site (SRS), South Carolina

Detailed analysis and synthesis of geophysical, core, and hydrologic data from 230 wells were used to delineate the hydrostratigraphy and aquifer characteristics of the General Separations Area at SRS. The study area is hydrologically bounded on the north and northwest by Upper Three Runs Creek (UTRC) and on the south by Fourmile Branch (FB). The Cretaceous-Tertiary sedimentary sequence underlying the study area is divided into two Aquifer Systems; in ascending order, Aquifer Systems I and 11. The study concentrated on Aquifer System U, which includes all the Tertiary sediments above the Black Mingo Group (Paleocene) to the water table. This report includes a series of lithostratigraphic cross-sections, piezometric gradient profiles, head ratio contour maps, aquifer isopach maps, and potentiometric surface maps which illustrate the aquifer characteristics of the study area.
Date: January 1, 1991
Creator: Aadland, R. K.; Harris, M. K.; Lewis, C. M.; Gaughan, T. F. & Westbrook, T. M.
Object Type: Report
System: The UNT Digital Library
Hydrostratigraphy of the General Separations Area, Savannah River Site (SRS), South Carolina (open access)

Hydrostratigraphy of the General Separations Area, Savannah River Site (SRS), South Carolina

Detailed analysis and synthesis of geophysical, core, and hydrologic data from 230 wells were used to delineate the hydrostratigraphy and aquifer characteristics of the General Separations Area at SRS. The study area is hydrologically bounded on the north and northwest by Upper Three Runs Creek (UTRC) and on the south by Fourmile Branch (FB). The Cretaceous-Tertiary sedimentary sequence underlying the study area is divided into two Aquifer Systems; in ascending order, Aquifer Systems I and 11. The study concentrated on Aquifer System U, which includes all the Tertiary sediments above the Black Mingo Group (Paleocene) to the water table. This report includes a series of lithostratigraphic cross-sections, piezometric gradient profiles, head ratio contour maps, aquifer isopach maps, and potentiometric surface maps which illustrate the aquifer characteristics of the study area.
Date: January 1, 1991
Creator: Aadland, R. K.; Harris, M. K.; Lewis, C. M.; Gaughan, T. F. (Westinghouse Savannah River Co., Aiken, SC (United States)) & Westbrook, T. M. (Dames and Moore, Atlanta, GA (United States))
Object Type: Report
System: The UNT Digital Library
Lithological and hydrological characteristics of the tertiary hydrostratigraphic systems of the general separations area at the Savannah River Site (open access)

Lithological and hydrological characteristics of the tertiary hydrostratigraphic systems of the general separations area at the Savannah River Site

The General Separations Area (GSA) is an approximately 15-square-mile area near the geographic center of the Savannah River Site (SRS). The SRS is located in the Upper Atlantic Coastal Plain physiographic province of South Carolina on the Aiken Plateau at an elevation of approximately 300 feet above mean sea level. The sedimentary sequence of the GSA comprises unconsolidated sediments ranging in age from Cretaceous to Holocene with isolated zones of consolidated sediments. The Tertiary sediments are composed of sand, silt, clay, and calcareous materials of varying composition. The alpha-numeric hydrostratigraphic nomenclature proposed by Aadland (1990) is used herein. The Tertiary-age lithostratigraphic sequence at the GSA is composed predominantly of terrigenous clastics interspersed with carbonate-rich clastics and limestones. The calcareous lithologies are discontinuous and divided into a lower and upper zone. 15 refs., 2 figs.
Date: January 1, 1990
Creator: Aadland, R.K. (Westinghouse Savannah River Co., Aiken, SC (USA)); Harris, M.K. & Westbrook, T.M. (Dames and Moore, Atlanta, GA (USA))
Object Type: Article
System: The UNT Digital Library
Application of imitation steam'' systems to hot water district heating and cooling systems (open access)

Application of imitation steam'' systems to hot water district heating and cooling systems

Pequod Associates, Inc. and District Energy St. Paul, Inc. installed a pilot project of an innovative District Heating technology through a contract with the US DOE. This applied research was funded by the Energy Research and Development Act (94--163) for District Heating and Cooling Research. The experimental design is an intervention technique that permits hot water district heating systems to connect to buildings equipped with steam heating systems to connect to buildings equipped with steam heating systems. This method can substantially reduce conversion costs in many older buildings. The method circulates Imitation Steam, which is moist hot air, as a heating medium in standard steam radiators and steam heating coils. Based on the operation of the system during the 1989--90 and 1990--91 winter heating seasons, we conclude the following: the basic concept of using Imitation Steam was proved feasible. The performance of the system can be improved beyond the levels achieved in this installation. Imitation Steam did not cause significant corrosion in the piping system. The technology can be used by other district heating systems to lower conversion costs and increase market penetration. Among the additional benefits from this technology are: eliminating old, inefficient boilers; lower maintenance costs; improved fuel …
Date: October 1, 1991
Creator: Aalto, P.J. & Chen, D.B.
Object Type: Report
System: The UNT Digital Library
Dealing with duplicate regulations and conflicting jurisdictions (open access)

Dealing with duplicate regulations and conflicting jurisdictions

There are a number of situations where mixed wastes are regulated by dual regulations and regulators. This presentation attempts to show where such duplication exists and how it evolved historically through legislative actions. The presentation includes a discussion of strategies that have been used to deal with the problems that result from duplicate regulations and jurisdictional conflicts. The RCRA and AEA regulations are really more similar than dissimilar. There are significant issues that must be worked through with the regulators. It is most important to work with your regulators early in process. The following are suggestions for dealing with the regulators. (1) Know the regulations in advance of discussions. (2) Begin dialogue with the regulator(s) as early as possible and get to know the people you will be dealing with -- and let them know you. (3) Explain the technical/regulatory issues/problems that you face at your facility in sufficient detail that they are clearly understood, and work with the regulator(s) to reasonably address them in the language/requirements of the permit. (4) Always attempt to comply with the regulations first before going in with a variance request -- document your efforts, and be honest with your assessment of issues. (5) Don't …
Date: January 1, 1991
Creator: Aamodt, P. L.
Object Type: Article
System: The UNT Digital Library
Fundamental studies of fusion plasmas (open access)

Fundamental studies of fusion plasmas

The major portion of this program is devoted to critical ICH phenomena. The topics include edge physics, fast wave propagation, ICH induced high frequency instabilities, and a preliminary antenna design for Ignitor. This research was strongly coordinated with the world's experimental and design teams at JET, Culham, ORNL, and Ignitor. The results have been widely publicized at both general scientific meetings and topical workshops including the speciality workshop on ICRF design and physics sponsored by Lodestar in April 1992. The combination of theory, empirical modeling, and engineering design in this program makes this research particularly important for the design of future devices and for the understanding and performance projections of present tokamak devices. Additionally, the development of a diagnostic of runaway electrons on TEXT has proven particularly useful for the fundamental understanding of energetic electron confinement. This work has led to a better quantitative basis for quasilinear theory and the role of magnetic vs. electrostatic field fluctuations on electron transport. An APS invited talk was given on this subject and collaboration with PPPL personnel was also initiated. Ongoing research on these topics will continue for the remainder fo the contract period and the strong collaborations are expected to continue, enhancing …
Date: May 26, 1992
Creator: Aamodt, R. E.; Catto, P. J.; D'Ippolito, D. A.; Myra, J. R. & Russell, D. A.
Object Type: Report
System: The UNT Digital Library
Fundamental studies of fusion plasmas (open access)

Fundamental studies of fusion plasmas

Work on ICRF interaction with the edge plasma is reported. ICRF generated convective cells have been established as an important mechanism for influencing edge transport and interaction with the H-mode, and for controlling profiles in the tokamak scrape-off-layer. Power dissipation by rf sheaths has been shown to be significant for some misaligned ICRF and IIBW antenna systems. Near-field antenna sheath work has been extended to the far-field case, important for experiments with low single pass absorption. Impurity modeling and Faraday screen design support has been provided for the ICRF community. In the area of core-ICRF physics, the kinetic theory of heating by applied ICRF waves has been extended to retain important geometrical effects relevant to modeling minority heated tokamak plasmas, thereby improving on the physics base that is standard in presently employed codes. Both the quasilinear theory of ion heating, and the plasma response function important in wave codes have been addressed. In separate studies, it has been shown that highly anisotropic minority heated plasmas can give rise to unstable field fluctuations in some situations. A completely separate series of studies have contributed to the understanding of tokamak confinement physics. Additionally, a diffraction formalism has been produced which will be …
Date: April 27, 1993
Creator: Aamodt, R. E.; Catto, P. J.; D'Ippolito, D. A.; Myra, J. R. & Russell, D. A.
Object Type: Report
System: The UNT Digital Library