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4 MW Fast Wave Current Drive Upgrade for DIII-D (open access)

4 MW Fast Wave Current Drive Upgrade for DIII-D

The DIII-D program has just completed a major addition to its ion cyclotron range of frequency (ICRF) systems. This upgrade project added two new fast wave current drive (FWCD) systems, with each system consisting of a 2 MW, 30 to 120 MHz transmitter, ceramic insulated transmission lines and tuner elements, and water-cooled four-strap antenna. With this addition of 4 MW of FWCD power to the original 2 MW, 30 to 60 MHz capability, experiments can be performed that will explore advanced tokamak plasma configurations by using the centrally localized current drive to effect current profile modifications.
Date: September 1, 1994
Creator: Callis, R. W.; Cary, W. P. & Baity, F. W.
System: The UNT Digital Library
An 8-meter-long coupled cavity RFQ linac (open access)

An 8-meter-long coupled cavity RFQ linac

A model has been constructed of an 8-m-long high energy (7 MeV) Radio-Frequency Quadrupole (RFQ) to prove the concept of a resonantly coupled RFQ. The model consists of four 2-in-long RFQ segments resonantly coupled together. A small gap (3 mm) between the vane tips, at the segment joints, provides capacitive coupling. This model is of a RFQ designed for a proposed Los Alamos Accelerator Performance Demonstration Facility (APDF). The RFQ, as designed, will operate cw at 350 kHz and accelerate a 100-mA beam of protons to 7 MeV.
Date: September 1, 1994
Creator: Young, L. M.
System: The UNT Digital Library
1987 Overview of the free-piston Stirling technology for space power application (open access)

1987 Overview of the free-piston Stirling technology for space power application

An overview is presented of the National Aeronautics and Space Administration (NASA) Lewis Research Center free-piston Stirling engine activities directed toward space-power application. Free-piston Stirling technology is applicable for both solar and nuclear powered systems. As such, NASA Lewis serves as the project office to manage the newly initiated NASA SP-100 Advanced Technology Program. This 5-yr program provides the technology thrust for providing significant component and subsystem options for increased efficiency, reliability and survivability, and power output growth at reduced specific mass. One of the major elements of the program is the development of advanced power conversion concepts of which the Stirling cycle is a viable growth candidate. Under this program the status of the 25 kWe opposed-piston Space Power Demonstrator Engine (SPDE) is presented. Included in the SPDE discussion are comparisons between predicted and experimental engine performance, enhanced performance resulting from regenerator modification, increased operating stroke brought about by isolating the gas bearing flow between the displacer and power piston, identifying excessive energy losses and recommending corrective action, and a better understanding of linear alternator design and operation. Technology work is also conducted on heat exchanger concepts, both design and fabrication, to minimize the number of joints as well …
Date: September 1, 1994
Creator: Slaby, J. G. & Alger, D. L.
System: The UNT Digital Library
1994 Department of Energy Records Management Conference (open access)

1994 Department of Energy Records Management Conference

The Department of Energy (DOE) Records Management Group (RMG) provides a forum for DOE and its contractor personnel to review and discuss subjects, issues, and concerns of common interest. This forum will include the exchange of information, and interpretation of requirements, and a dialog to aid in cost-effective management of the DOE Records Management program. This report contains the contributions from this forum.
Date: September 1, 1994
Creator: unknown
System: The UNT Digital Library
21PF overpacks: Phenolic-foam induced corrosion (open access)

21PF overpacks: Phenolic-foam induced corrosion

The 21PF overpack was developed in the 1960s and approved for use in the 1970s by the US Department of Transportation (DOT). This package, used for the transport of uranium hexafluoride enriched >1%, has had a history of severe metal corrosion, water ingress, and subsequent leakage. Problems associated with corrosion and water leaking from 21PF overpacks caused the DOT to seek public comments and to undertake rulemaking action. As a result, the DOT required modifications and refurbishment of existing overpacks, and specification changes for the fabrication of new 21PF overpacks. Recent studies conducted by the roofing industry indicate that phenolic foam has caused severe corrosion in metal roofing structures, and its use is being curtailed. These findings need to be explored in order to determine if phenolic foam in 21PF overpacks causes corrosion and compromises the package integrity. Metallic corrosion induced by phenolic foam may affect the continued use of the 21PF overpack because damage to the structural integrity of the metal parts of the packaging will affect its ability to meet design specifications.
Date: September 1, 1994
Creator: Kovac, F. M.
System: The UNT Digital Library
Accident analysis for US fast burst reactors (open access)

Accident analysis for US fast burst reactors

In the US fast burst reactor (FBR) community there has been increasing emphasis and scrutiny on safety analysis and understanding of possible accident scenarios. This paper summarizes recent work in these areas that is going on at the different US FBR sites. At this time, all of the FBR facilities have or in the process of updating and refining their accident analyses. This effort is driven by two objectives: to obtain a more realistic scenario for emergency response procedures and contingency plans, and to determine compliance with changing regulatory standards.
Date: September 1, 1994
Creator: Paternoster, R.; Flanders, M. & Kazi, H.
System: The UNT Digital Library
Acoustic emission sensor radiation damage threshold experiment (open access)

Acoustic emission sensor radiation damage threshold experiment

Determination of the threshold for damage to acoustic emission sensors exposed to radiation is important in their application to leak detection in radioactive waste transport and storage. Proper response to system leaks is necessary to ensure the safe operation of these systems. A radiation impaired sensor could provide ``false negative or false positive`` indication of acoustic signals from leaks within the system. Research was carried out in the Radiochemical Technology Division at Oak Ridge National Laboratory to determine the beta/gamma radiation damage threshold for acoustic emission sensor systems. The individual system consisted of an acoustic sensor mounted with a two part epoxy onto a stainless steel waveguide. The systems were placed in an irradiation fixture and exposed to a Cobalt-60 source. After each irradiation, the sensors were recalibrated by Physical Acoustics Corporation. The results were compared to the initial calibrations performed prior to irradiation and a control group, not exposed to radiation, was used to validate the results. This experiment determines the radiation damage threshold of each acoustic sensor system and verifies its life expectancy, usefulness and reliability for many applications in radioactive environments.
Date: September 1, 1994
Creator: Beeson, K. M. & Pepper, C. E.
System: The UNT Digital Library
Additional degrees of freedom in skyrmion motion (open access)

Additional degrees of freedom in skyrmion motion

The authors consider the quantization of chiral solitons with baryon number B > 1. Classical solitons are obtained within the framework of a variational approach. From the form of the soliton solution it can be seen that besides the group of symmetry describing transformations of the configuration as a whole there are additional symmetries corresponding to internal transformations. Taking into account the additional degrees of freedom leads to some sort of spin alignment for light nuclei and gives constraints on their spectra.
Date: September 1, 1994
Creator: Musatov, I.; Nikolaev, V. & Tkachev, O.
System: The UNT Digital Library
Advance plant severe accident/thermal hydraulic issues for ACRS (open access)

Advance plant severe accident/thermal hydraulic issues for ACRS

The ACRS has been reviewing various advance plant designs for certification. The most active reviews have been for the ABWR, AP600, and System 80+. We have completed the reviews for ABWR and System 80+ and are presently concentrating on AP600. The ACRS gave essentially unqualified certification approval for the two completed reviews, yet,,during the process of review a number of issues arose and the plant designs changed somewhat to accommodate some of the ACRS concerns. In this talk, I will describe some of the severe accident and thermal hydraulic related issues we discussed in our reviews.
Date: September 1, 1994
Creator: Kress, T. S.
System: The UNT Digital Library
Advanced fission and fossil plant economics-implications for fusion (open access)

Advanced fission and fossil plant economics-implications for fusion

In order for fusion energy to be a viable option for electric power generation, it must either directly compete with future alternatives or serve as a reasonable backup if the alternatives become unacceptable. This paper discusses projected costs for the most likely competitors with fusion power for baseload electric capacity and what these costs imply for fusion economics. The competitors examined include advanced nuclear fission and advanced fossil-fired plants. The projected costs and their basis are discussed. The estimates for these technologies are compared with cost estimates for magnetic and inertial confinement fusion plants. The conclusion of the analysis is that fusion faces formidable economic competition. Although the cost level for fusion appears greater than that for fission or fossil, the costs are not so high as to preclude fusion`s potential competitiveness.
Date: September 1, 1994
Creator: Delene, J. G.
System: The UNT Digital Library
Aeolian removal of dust from radiator surfaces on Mars (open access)

Aeolian removal of dust from radiator surfaces on Mars

Simulated radiator surfaces made of arc-textured copper and niobium-one percent-zirconium, and ion beam textured graphite and carbon-carbon composite were fabricated and their integrated spectral emittance characterized from 300 to 3000 K. A thin layer of aluminum oxide, basalt, or iron (III) oxide dust was then deposited on them, and they were subjected to low pressure winds in the Martian Surface Wind Tunnel. It has been found that dust deposited on simulated radiator surfaces may or may not seriously lower their integrated spectral emittance, depending upon the characteristics of the dust. With Al{sub 2}O{sub 3} there is no appreciable degradation of emittance on a dusted sample, with basaltic dust there is a 10-20 percent degradation, and with Fe{sub 2}O{sub 3} a 20-40 percent degradation. It was also found that very high winds on dusted highly textured surfaces can result in their abrasion. Degradation in emittance due to abrasion was found to vary with radiator material. Arc-textured copper and Nb-1%Zr was found to be more susceptible to emittance degradation than graphite or carbon-carbon composite. The most abrasion occurred at low angles, peaking at the 22.5{degrees} test samples.
Date: September 1, 1994
Creator: Gaier, J. R.; Perez-Davis, M. E.; Rutledge, S. K. & Hotes, D.
System: The UNT Digital Library
Air sampling at Oak Ridge National Laboratory (open access)

Air sampling at Oak Ridge National Laboratory

New and more detailed requirements for air sampling and real-time monitoring made it necessary to review and update ORNL`s air sampling/monitoring program. As the first step in upgrading the air sampling/monitoring program, an evaluation of facilities indicated that over half of ORNL`s present inventory of real-time air monitors should be eliminated or replaced by air samplers. Secondly, users and owners had to be educated concerning the capabilities, recommended uses, and relative merits of air samplers and real-time monitors. Finally, specifications were written for both high- and low-volume air samplers, based on ORNL`s specific needs. Two types of air samplers are being constructed for use at ORNL, with each unit costing under $1,000.
Date: September 1, 1994
Creator: Gregory, D. C.
System: The UNT Digital Library
ALCHEMI of Fe-doped B2-ordered NiAl alloys with different doping levels (open access)

ALCHEMI of Fe-doped B2-ordered NiAl alloys with different doping levels

The ALCHEMI technique yields exact expressions for best-fit parameters in terms of ionization localization constants and site distributions of 3 elements distributed over two sublattices. In this paper, a graphical plotting technique is applied to Fe-doped NiAl B2-ordered alloys Ni{sub 0.5-x}Fe{sub x}Al{sub 0.5}, with x=0.02 or 0.10. The thin foil samples were examined in an electron microscope with an x-ray spectrometer.
Date: September 1, 1994
Creator: Anderson, I. M.; Bentley, J. & Duncan, A. J.
System: The UNT Digital Library
Alloying effects on the high-temperature oxidation resistance of Cr-Cr{sub 2}Nb (open access)

Alloying effects on the high-temperature oxidation resistance of Cr-Cr{sub 2}Nb

Alloying effects on the high-temperature oxidation resistance of Cr-Cr{sub 2}Nb were examined on the basis of isothermal exposures to air at 950 C. Additions of either Re and Al or Fe, Ni, and Al had relatively little effect on weight gains relative to the Cr-6% Nb binary alloy. One alloying element that improved the mechanical behavior of Cr-Cr{sub 2}Nb alloys substantially increased the oxidation rates and spallation susceptibilities of Cr-6 and -12% Nb alloys. However, the addition of another element completely offset these deleterious effects. The presence of this latter element resulted in the best overall oxidation behavior (in terms of both weight gains and spallation tendencies) of all Cr-Cr{sub 2}Nb compositions. Its beneficial effect can be attributed to improvement in the oxidation resistance of the Cr-rich phase.
Date: September 1, 1994
Creator: Tortorelli, P. F. & DeVan, J. H.
System: The UNT Digital Library
Alternative barrier layers for surface covers in dry climates (open access)

Alternative barrier layers for surface covers in dry climates

Surface covers are one of the most widespread remediation and waste management options in all climates. Barrier layers to limit percolation through cover systems are principal features of engineered, multi-component cover designs. Conventional barrier layer components developed for humid climates have limitations in dry climates. One alternative barrier layer is a capillary barrier, which consists of a fine-over-coarse soil arrangement. The capacity of capillary barrier to laterally divert downward moving water is the key to their success. Another alternative is a dry barrier, in which atmospheric air is circulated through a coarse layer within the cover to remove water vapor. Incorporating a coarse layer which stores water for subsequent removal by air flow reduces the requirements for the air flow velocity and increases the applicability of the dry barrier.
Date: September 1, 1994
Creator: Stormont, J. C.
System: The UNT Digital Library
Alternative power generation concepts for space (open access)

Alternative power generation concepts for space

With the advent of the NASA Space Station, there has emerged a general realization that large quantities of power in space are necessary and, in fact, enabling. This realization has led to the examination of alternative options to the ubiquitous solar array/battery power system. Several factors led to the consideration of solar dynamic and nuclear power systems. These include better scaling to high power levels, higher efficiency conversion and storage subsystems, and lower system specific mass. The objective of this paper is to present the results of trade and optimization studies that high-light the potential of solar and nuclear dynamic systems relative to photovoltaic power systems.
Date: September 1, 1994
Creator: Brandhorst, H. W., Jr.; Juhasz, A. J. & Jones, B. I.
System: The UNT Digital Library
Amorphization of sapphire during ion beam mixing (open access)

Amorphization of sapphire during ion beam mixing

Earlier studies indicated that implantation of zirconium into sapphire at room temperature produced an amorphous layer at a critical composition of approximately 6.5% (cation). Further insight into the amorphization of sapphire has been provided by ion beam mixing studies. Bi-layer couples of {approx}80 nm thick polycrystalline ZrO{sub 2} films deposited on the (0001) face of {alpha}-Al{sub 2}O{sub 3} single crystals were irradiated to 4 {times} 10{sup 16} ions/cm{sup 2} with Kr (475 keV, 20{degree}C), or Cr (340 keV, 20{degree}C or {approx}900{degree}C). Transmission electron microscopy showed the unirradiated couples to have sharp, planar interfaces between the films and substrates. Recoil mixing by both ion species gave Zr concentrations greater than 10% (cation) to depths of 10-20 nm. An amorphous layer containing Zr was present at the interface for samples irradiated at room temperature. The sample mixed at the elevated temperature contained a sharp interface similar to the as-deposited sample. The present results suggest that both irradiation-produced damage (defects) and certain chemical species are required to amorphize sapphire.
Date: September 1, 1994
Creator: Joslin, D. L.; McHargue, C. J.; White, C. W. & Evans, N. D.
System: The UNT Digital Library
Analytic Perturbation Analysis of Discrete Event Dynamic Systems (open access)

Analytic Perturbation Analysis of Discrete Event Dynamic Systems

This paper considers a new Analytic Perturbation Analysis (APA) approach for Discrete Event Dynamic Systems (DEDS) with discontinuous sample-path functions with respect to control parameters. The performance functions for DEDS usually are formulated as mathematical expectations, which can be calculated only numerically. APA is based on new analytic formulas for the gradients of expectations of indicator functions; therefore, it is called an analytic perturbation analysis. The gradient of performance function may not coincide with the expectation of a gradient of sample-path function (i.e., the interchange formula for the gradient and expectation sign may not be valid). Estimates of gradients can be obtained with one simulation run of the models.
Date: September 1, 1994
Creator: Uryasev, S.
System: The UNT Digital Library
Analytical characterization of high-level mixed wastes using multiple sample preparation treatments (open access)

Analytical characterization of high-level mixed wastes using multiple sample preparation treatments

The Analytical Chemistry Laboratory at the Pacific Northwest Laboratory in Richland, Washington, is actively involved in performing analytical characterization of high-level mixed waste from Hanford`s single shell and double shell tank characterization programs. A full suite of analyses is typically performed on homogenized tank core samples. These analytical techniques include inductively-coupled plasma-atomic emission spectroscopy, total organic carbon methods and radiochemistry methods, as well as many others, all requiring some type of remote sample-preparation treatment to solubilize the tank sludge material for analysis. Most of these analytical methods typically use a single sample-preparation treatment, inherently providing elemental information only. To better understand and interpret tank chemistry and assist in identifying chemical compounds, selected analytical methods are performed using multiple sample-preparation treatments. The sample preparation treatments used at Pacific Northwest Laboratory for this work with high-level mixed waste include caustic fusion, acid digestion, and water leach. The type of information available by comparing results from different sample-prep treatments includes evidence for the presence of refractory compounds, acid-soluble compounds, or water-soluble compounds. Problems unique to the analysis of Hanford tank wastes are discussed. Selected results from the Hanford single shell ferrocyanide tank, 241-C-109, are presented, and the resulting conclusions are discussed.
Date: September 1, 1994
Creator: King, A. G.; Baldwin, D. L.; Urie, M. W. & McKinley, S. G.
System: The UNT Digital Library
Application of a dimensionless parameter model for Laser Beam Welding (open access)

Application of a dimensionless parameter model for Laser Beam Welding

A new dimensionless parameter model for continuous wave laser welding that relates the size of the weld to the energy absorbed by the part is described. The model has been experimentally validated previously through calorimetric determinations of the net heat input and metallographic measurements of the weld size. It will be shown that both the melting efficiency and energy transfer efficiency for LBW are quite variable and need to be considered when selecting processing conditions. Specific applications will be detailed in order to observe the simplicity and value of the model in laser weld process development. It will be shown that by using certain dimensionless parameters one can determine the energy transfer efficiency and thereby correctly select processing conditions that more fully utilize the available laser output power. In applications where minimizing heat input to the surrounding weldment is paramount, the dimensionless parameters can be used to select conditions that maximize melting efficiency.
Date: September 1, 1994
Creator: Fuerschbach, P. W.
System: The UNT Digital Library
Application of diode lasers to the isotopically selective determination of uranium in oxides by optogalvanic spectroscopy (open access)

Application of diode lasers to the isotopically selective determination of uranium in oxides by optogalvanic spectroscopy

We have observed isotopically selective diode laser-excited optogalvanic effects in uranium at 778.42 and 776.19 nm. The samples were natural abundance uranium oxide, as well as depleted (0.3% {sup 235}U), natural (0.7% {sup 235}U) and enriched (9.75% {sup 235}U) uranium metal or powders. The measurements were carried out in a demountable-cathode glow discharge cell. Preliminary evaluations of precision for uranium isotopic ratios measured using this technique suggest that it should have broad analytical applications for uranium and other amenable actinides or lanthanides.
Date: September 1, 1994
Creator: Young, J. P.; Barshick, C. M.; Shaw, R. W. & Ramsey, J. M.
System: The UNT Digital Library
Application of spectral line shapes to the study of high density ICF plasmas (open access)

Application of spectral line shapes to the study of high density ICF plasmas

Spectral line broadening manifests itself in the study of high density inertial confinement fusion (ICF) plasmas in two important ways. First, comparison between measured and calculated lineshapes of individual spectral lines or groups of lines is used to diagnose plasma conditions in dense ICF plasmas, particularly in implosions. Secondly, through the emission and absorption coefficients spectral lineshapes serve as important inputs to plasma spectroscopy simulation codes which calculate simulated spectra from ICF targets. We discuss recent results from each of these areas. With regard to lineshape diagnostics, the advent of generalized line broadening codes has allowed the line profiles of complex multielectron emitters to be considered for diagnostic purposes. Particular example of this is the use of Ar He-{beta} and its associated dielectronic satellites as a diagnostic of T{sub e} and N{sub e}, as well as the development of Ne-like Xe line broadening as a density diagnostic. With respect to simulation codes, the implementation of detailed lineshapes in calculations of this type is in many ways in its infancy. We present here examples of cases where effects related to spectral lineshapes such as continuum lowering and line transfer of Stark broadened lines are important so as to provide a stimulus …
Date: September 1, 1994
Creator: Keane, C. J.; Hammel, B. A.; Langer, S. H.; Lee, R. W.; Calisti, A.; Godbert, L. et al.
System: The UNT Digital Library
Applications of classical detonation theory (open access)

Applications of classical detonation theory

Classical detonation theory is the basis for almost all calculations of explosive systems. One common type of calculation is of the detailed behavior of inert parts driven by explosive, predicting pressures, velocities, positions, densities, energies, etc as functions of time. Another common application of the theory is predicting the detonation state and expansion isentrope of a new explosive or mixtures, perhaps an explosive that has not yet been made. Both types of calculations are discussed.
Date: September 1, 1994
Creator: Davis, W. C.
System: The UNT Digital Library
Approaches to the design of structural ceramics incorporating whiskers and particulate phases (open access)

Approaches to the design of structural ceramics incorporating whiskers and particulate phases

Advances in the technologically and commercially important areas of energy production and conversion, transportation, chemical processing, manufacturing, electronics, and communications are predicted upon the development of materials with greatly improved performance. Many of these components will be exposed to tensile stresses, and possibly quite high temperatures, which will require that the materials be designed to (1) achieve greater fracture resistance, (2) resist deformation at elevated temperatures, and (3) achieve the main component function. Here, theoretical modeling and observations of crack propagation in ceramics and composites are combined to identify and characterize mechanisms that contribute to fracture resistance and strength. Materials processing studies can then be employed to (1) develop the microstructural features suggested by the models and (2) understand the mechanisms involved in the generation of such microstructures. In this paper, the authors address how these various aspects can be used to enhance the mechanical performance of zirconia toughened ceramics (specifically involving transformation toughening) and whisker-reinforced ceramics with comments on other composites incorporating other discontinuous phases.
Date: September 1, 1994
Creator: Becher, P. F.; Lin, H. T.; Hsueh, C. H.; Alexander, K. B.; Warwick, W. H. & Waters, S. B.
System: The UNT Digital Library