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in creator/contributor: "Trester, P.W."

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Changes in near-surface microstructure of metallic limiters following one year of service in Doublet III

The structural alloys Ta-10W, Mo, and Inconel X-750 were used for plasma limiters during the 3-MW ohmic heating experiments of the Doublet III tokamak. Post-service examinations of these limiters are reviewed. Near-surface melting, cracking, and microstructural changes are shown and discussed. During III service, elements from other metallic components were transported by the plasma and deposited on the limiter surface; significantly, high concentrations of Ni, Fe, Mo, and C were detected in th… more

Date: August 1, 1981

Creator: Trester, P. W.; Sevier, D. L. & Sabado, M. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Determination of a permissible size flaw in the Doublet III toroidal field coil

The thick plates of copper alloy 155 used for toroidal field coils (B-coils) in Doublet III contain material flaws that originated during the manufacturing of the plate stock. The methodology is reviewed in which detailed stress analysis, fracture mechanics, and fatigue testing are used to determine what size material flaws are permissible within the finger-joint region of the B-coil for a specified service life of 100,000 cycles under the maximum operating field of 40 kG. This paper presents t… more

Date: October 1, 1979

Creator: Reis, E. E.; Sweig, R. A. & Trester, P. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mechanical properties considerations for use of epoxy insulators and bonded joints in neutral beam ion sources

In the Doublet III (D-III) neutral beam injectors, cast, rigid-epoxy insulators are joined to the AISI 304 stainless steel corona rings with semi-rigid epoxy adhesive. Selected mechanical properties of these materials were measured between 11/sup 0/C and 65/sup 0/C, well below the material temperature limits, to identify the trends and to confirm adequate mechanical strength for the insulators. Significant creep deformation was measured at 22/sup 0/C. Empirical relationships were developed to p… more

Date: October 1, 1981

Creator: Doll, D. W.; Trester, P. W. & Staley, H. G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Improved performance of TiC-coated graphite limiters by surface texturing

TicC-coated graphite limiters are currently in wide use as tokamak limiters. These limiters usually suffer a groove type of damage caused by plasma disruptions. A surface texturing treatment is described that reduces the occurrence of this type of damage.

Date: January 1, 1983

Creator: Whitley, J. B.; Mattox, D. M.; Trester, P. W. & Emerson, L. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Doublet III limiter performance and implications for mechanical design and material selection for future limiters

The plasma limiter system for Doublet III is described. Initially, high-Z materials, Ta-10W for the primary limiter and Mo for the backup limiters, were selected as the most attractive metallic candidates from the standpoint of thermal and structural properties. For the purpose of evaluating the effect of material Z on plasma performance, the nonmagnetic, Ni-base alloy Inconel X-750 was selected for a medium-Z limiter material. Graphite, a low-Z material, will likely be the next limiter materia… more

Date: October 1, 1979

Creator: Sabado, M. M.; Marcus, F. B.; Trester, P. W. & Wesley, J. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Metallurgical Bonding Development of V-4Cr-4Ti Alloy for the DIII-D Radiative Divertor Program

General Atomics (GA), in conjunction with the Department of Energy`s (DOE) DIII-D Program, is carrying out a plan to utilize a vanadium alloy in the DIII-D tokamak as part of the DIII-D Radiative Divertor (RD) upgrade. The V-4Cr-4Ti alloy has been selected in the U.S. as the leading candidate vanadium alloy for fusion applications. This alloy will be used for the divertor fabrication. Manufacturing development with the V-4Cr-4Ti alloy is a focus of the DIII-D RD Program. The RD structure, part … more

Date: June 1, 1998

Creator: Smith, J. P.; Johnson, W. R. & Trester, P. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Boron carbide-based coatings on graphite for plasma facing components

In the effort to evaluate boron-rich coatings as plasma facing surfaces in fusion devices, a new process for applying boron carbide (B{sub 4}C) coatings to graphite was developed. The process entails eutectic melting of the carbon (C) substrate surface with a precursor layer of B{sub 4}C particles. Adherent coatings were achieved which consisted of two layers: a surface layer and a graded penetration zone in the outer portion of the substrate. The surface-layer microstructure was multiphase and… more

Date: January 1, 1994

Creator: Valentine, P. G.; Trester, P. W.; Winter, J.; Linke, J.; Duwe, R.; Wallura, E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Utilization of vanadium alloys in the DIII-D Radiative Divertor Program

Vanadium alloys are attractive candidate structural materials for fusion power plants because of their potential for minimum environmental impact due to low neutron activation and rapid activation decay. They also possess favorable material properties for operation in a fusion environment. General Atomics (GA), in conjunction with Argonne National Laboratory (ANL) and Oak Ridge National Laboratory (ORNL), has developed a plan for the utilization of vanadium alloys as part of the Radiative Diver… more

Date: October 1995

Creator: Smith, J. P.; Johnson, W. R.; Stambaugh, R. D.; Trester, P. W.; Smith, D. & Bloom, E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Hydrogen production by the GA sulfur-iodine process: a progress report

The progress of the overall total development effort of the General Atomic (GA) sulfur-iodine thermochemical water-splitting cycle over the last two years is summarized. The major accomplishments have been: significant improvements in the chemistry of the process; development, review, and revision of an engineering flowsheet, resulting in a thermal process efficiency of 47%; screening, identification, and testing of potential materials-of-construction for the corrosive process fluids; small-sca… more

Date: May 1, 1980

Creator: Besenbruch, G.E.; McCorkle, K.H.; Norman, J.H.; O'Keefe, D.R.; Schuster, J.R.; Trester, P.W. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Performance of V-4Cr-4Ti materials exposed to the DIII-D tokamak environment.

No Description Available.

Date: October 17, 2001

Creator: Tsai, H.; Johnson, W. R.; Yan, Y.; Trester, P. W.; Bozek, A.; King, J. F. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Vanadium alloys for the radiative divertor program of DIII-D

Vanadium alloys provide an attractive solution for fusion power plants as they exhibit a potential for low environmental impact due to low level of activation from neutron fluence and a relatively short half-life. They also have attractive material properties for use in a reactor. General Atomics along with Argonne National Laboratory (ANL) and Oak Ridge National Laboratory (ORNL), has developed a plan to utilize vanadium alloys as part of the Radiative Divertor Project (RDP) modification for t… more

Date: October 1, 1995

Creator: Smith, J. P.; Johnson, W. R.; Stambaugh, R. D.; Trester, P. W.; Smith, D. & Bloom, E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Tensile and impact properties of V-4Cr-4Ti alloy heats 832665 and 832864.

Two large heats of V-4Cr-4Ti alloy were produced in the United States in the past few years. The first, 832665, was a 500 kg heat procured by the U.S. Department of Energy for basic fusion structural materials research. The second, 832864, was a 1300 kg heat procured by General Atomics for the DIII-D radiative divertor upgrade. Both heats were produced by Oremet-Wah Chang (previously Teledyne Wah Chang of Albany). Tensile properties up to 800 C and Charpy V-notch impact properties down to liqui… more

Date: November 8, 1999

Creator: Bray, T. S.; Tsai, H.; Nowicki, L. J.; Billone, M. C.; Smith, D. L.; Johnson, W. R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Status report on sulfur iodine thermochemical water-splitting cycle

Major process improvements which had been identified in an earlier phase of this program were investigated and their feasibility demonstrated. The engineering process flowsheet was revised to incorporate the newest process improvements. It is now being used for an estimate of hydrogen production cost from the General Atomic Company (GAC) cycle. An energy storage cycle for a solar adaptation of the sulfur-iodine cycle has been identified and is being evaluated along with features particularly co… more

Date: November 1, 1981

Creator: Besenbruch, G.E.; Brown, L.C.; Yoshimoto, M.; Norman, J.H.; O'Keefe, D.R.; Endo, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Performance of V-4Cr-4Ti Alloy Exposed to the JFT-2M Tokamak Environment

A long-term test has been conducted in the JFT-2M tokamak fusion device to determine the effects of environmental exposure on the mechanical and chemical behavior of a V-4Cr-4Ti alloy. Test specimens of the alloy were exposed in the outward lower divertor chamber of JFT-2M in a region away from direct contact with the plasma and were preheated to 300 C just prior to and during selected plasma discharges. During their nine-month residence time in JFT-2M, the specimens experienced approximately 2… more

Date: October 1, 1999

Creator: Johnson, W. R.; Trester, P. W.; Sengoku, S.; Ishiyama, S.; Fukaya, K.; Eto, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fabrication and Repair of Ion Source Components in the 80 keV Neutral Beam Lines for DIII-D

OAK-B135 After 8 years of operation, leaks began to develop in critical components of the ion sources of the 80 keV neutral beam lines in DIII-D. Operational adjustments were made that seemed to remedy the problems, but five years later leaks began occurring again, this time with greater frequency. Failures occurred in the stainless steel bellows and molybdenum rails of the grid rail modules as well as in the Langmuir probes. Failure analyses identified several root causes of the leaks and oper… more

Date: October 1, 2003

Creator: Grunloh, H. J.; Busath, J. L.; Callis, R. W.; Chiu, H. K.; DiMartino, M.; Hong, R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department