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Collaboration on Modeling of Ion Bernstein Wave Antenna Array and Coupling to Plasma on Tokamak Fusion Text Reactor. Final report

Description: This proposal was peer reviewed and funded as a Collaboration on ''Low Phase Speed Radio Frequency Current Drive Experiments at the Tokamak Fusion Test Reactor''. The original plans we had were to carry out the collaboration proposal by including a post doctoral scientist stationed at PPPL. In response to a 60+% funding cut, all expenses were radically pruned. The post doctoral position was eliminated, and the Principal Investigator (T. Intrator) carried out the brunt of the collaboration. Visits to TFTR enabled T. Intrator to set up access to the TFTR computing network, database, and get familiar with the new antennas that were being installed in TFTR during an up to air. One unfortunate result of the budget squeeze that TFTR felt for its last year of operation was that the experiments that we specifically got funded to perform were not granted run time on TFTR., On the other hand we carried out some modeling of the electric field structure around the four strap direct launch Ion Bernstein Wave (IBW) antenna that was operated on TFTR. This turned out to be a useful exercise and shed some light on the operational characteristics of the IBW antenna and its coupling to the plasma. Because of this turn of events, the project was renamed ''Modeling of Ion Bernstein Wave Antenna Array and Coupling to Plasma on Tokamak Fusion Test Reactor''.
Date: June 1, 2000
Creator: Intrator, T.
Partner: UNT Libraries Government Documents Department

A Fast Shutdown Technique for Large Tokamaks

Description: A practical method is proposed for the fast shutdown of a large ignited tokamak. The method consists of injecting a rapid series of 30-50 deuterium pellets doped with a small ( 0.0005%) concentration of Krypton impurity, and simultaneously ramping the plasma current and shaping fields down over a period of several seconds using the poloidal field system. Detailed modeling with the Tokamak Simulation Code using a newly developed pellet mass deposition model shows that this method should terminate the discharge in a controlled and stable way without producing significant numbers of runaway electrons. A partial prototyping of this technique was accomplished in TFTR.
Date: September 1, 1999
Creator: Fredrickson, E.; Schmidt, G.L.; Hill, K.; Jardin, S.C. & al, et
Partner: UNT Libraries Government Documents Department

Safety of magnetic fusion facilities: Volume 2, Guidance

Description: This document provides guidance for the implementation of the requirements identified in Vol. 1 of this Standard. This guidance is intended for the managers, designers, operators, and other personnel with safety responsibilities for facilities designated as magnetic fusion facilities. While Vol. 1 is generally applicable in that requirements there apply to a wide range of fusion facilities, this volume is concerned mainly with large facilities such as the International Thermonuclear Experimental Reactor (ITER). Using a risk-based prioritization, the concepts presented here may also be applied to other magnetic fusion facilities. This volume is oriented toward regulation in the Department of Energy (DOE) environment.
Date: July 1, 1995
Partner: UNT Libraries Government Documents Department

Apparatus and method for extracting power from energetic ions produced in nuclear fusion

Description: This invention is comprised of an apparatus and method of extracting power from energetic ions produced by nuclear fusion in a toroidal plasma to enhance respectively the toroidal plasma current and fusion reactivity. By injecting waves of predetermined frequency and phase traveling substantially in a selected poloidal direction within the plasma, the energetic ions become diffused in energy and space such that the energetic ions lose energy and amplify the waves. The amplified waves are further adapted to travel substantially in a selected toroidal direction to increase preferentially the energy of electrons traveling in one toroidal direction which, in turn, enhances or generates a toroidal plasma current. In an further adaptation, the amplified waves can be made to preferentially increase the energy of fuel ions within the plasma to enhance the fusion reactivity of the fuel ions. The described direct, or in situ, conversion of the energetic ion energy provides an efficient and economical means of delivering power to a fusion reactor.
Date: December 31, 1993
Creator: Fisch, N.J. & Rax, J.M.
Partner: UNT Libraries Government Documents Department

Compact tokamak reactors part 2 (numerical results)

Description: The authors describe a numerical optimization scheme for fusion reactors. The particular application described is to find the smallest copper coil spherical tokamak, although the numerical scheme is sufficiently general to allow many other problems to be solved. The solution to the steady state energy balance is found by first selecting the fixed variables. The range of all remaining variables is then selected, except for the temperature. Within the specified ranges, the temperature which satisfies the power balance is then found. Tests are applied to determine that remaining constraints are satisfied, and the acceptable results then stored. Results are presented for a range of auxiliary current drive efficiencies and different scaling relationships; for the range of variables chosen the machine encompassing volume increases or remains approximately unchanged as the aspect ratio is reduced.
Date: October 21, 1996
Creator: Wiley, J.C.; Wootton, A.J. & Ross, D.W.
Partner: UNT Libraries Government Documents Department

Numerical Study of Microwave Reflectometry in Plasmas with 2D Turbulent Fluctuations

Description: This paper describes a numerical study of the role played by 2D turbulent fluctuations in microwave reflectometry -- a radar technique for density measurements using the reflection of electromagnetic waves from a plasma cutoff. The results indicate that, if the amplitude of fluctuations is below a threshold which is set by the spectrum of poloidal wavenumbers, the measured backward field appears to originate from a virtual location behind the reflecting layer, and to arise from the phase modulation of the probing wave, with an amplitude given by 1D geometric optics. These results suggest a possible scheme for turbulence measurements in tokamaks, where the backward field is collected with a wide aperture antenna, and the virtual reflecting layer is imaged onto the plane of an array of detectors. Such a scheme should be capable of providing additional information on the nature of the short-scale turbulence observed in tokamaks, which still remains one of the unresolved issues in fusion research.
Date: February 1, 1998
Creator: Mazzucato, E.
Partner: UNT Libraries Government Documents Department

Hydrodynamic effects of eroded materials on response of plasma-facing component during a tokamak disruption

Description: Loss of plasma confinement causes surface and structural damage to plasma-facing materials (PFMs) and remains a major obstacle for tokamak reactors. The deposited plasma energy results in surface erosion and structural failure. The surface erosion consists of vaporization, spallation, and liquid splatter of metallic materials, while the structural damage includes large temperature increases in structural materials and at the interfaces between surface coatings and structural members. Comprehensive models (contained in the HEIGHTS computer simulation package) are being used self-consistently to evaluate material damage. Splashing mechanisms occur as a result of volume bubble boiling and liquid hydrodynamic instabilities and brittle destruction mechanisms of nonmelting materials. The effect of macroscopic erosion on total mass losses and lifetime is evaluated. The macroscopic erosion products may further protect PFMs from severe erosion (via the droplet-shielding effect) in a manner similar to that of the vapor shielding concept.
Date: October 25, 1999
Creator: Hassanein, A. & Konkashbaev, I.
Partner: UNT Libraries Government Documents Department

Possible applications of powerful pulsed CO{sub 2}-lasers in tokamak reactors

Description: Applications of powerful pulsed CO{sub 2}-lasers for injection of fuel tablets or creation of a protective screen from the vapor of light elements to protect against the destruction of plasma-facing components are discussed, and the corresponding laser parameters are determined. The possibility of using CO{sub 2}-lasers in modeling the phenomena of powerful and energetic plasma fluxes interaction with a wall, as in the case of a plasma disruption, is considered.
Date: August 1, 1998
Creator: Nastoyashchii, A.F.; Morozov, I.N. & Hassanein, A.
Partner: UNT Libraries Government Documents Department

Diagnostic of the spatial and velocity distribution of alpha particles in tokamak fusion reactor using beat-wave generated lower hybrid wave. Progress report, 1994--1995

Description: The alpha particle population from fusion reactions in a DT tokamak reactor can have dramatic effects on the pressure profiles, energetic particle confinement, and the overall stability of the plasma; thus leading to important design consideration of a fusion reactor based on the tokamak concept. In order to fully understand the effects of the alpha population, a non-invasive diagnostic technique suitable for use in a reacting plasma environment needs to be developed to map out both the spatial and velocity distribution of the alphas. The proposed experimental goals for the eventual demonstration of LH wave interaction with a fast ion population is given in the reduced 3 year plan in table 1. At present time the authors are approaching the 8th month in their first year of this project. Up to now, their main effort has been concentrated in the operation of the two beat wave sources in burst mode. The second priority in the experimental project is the probe diagnostics and computer aided data acquisition system. The progress made so far is given, and they are ready to perform the beat-wave generated lower hybrid wave experiment. Some theoretical calculation had been reported at APS meetings. More refined theoretical models are being constructed in collaboration with Drs. J. Rogers and E. Valeo at PPPL.
Date: March 5, 1995
Creator: Hwang, D.Q.; Horton, R.D. & Evans, R.
Partner: UNT Libraries Government Documents Department

Prospects for Tokamak Fusion Reactors

Description: This paper first reviews briefly the status and plans for research in magnetic fusion energy and discusses the prospects for the tokamak magnetic configuration to be the basis for a fusion power plant. Good progress has been made in achieving fusion reactor-level, deuterium-tritium (D-T) plasmas with the production of significant fusion power in the Joint European Torus (up to 2 MW) and the Tokamak Fusion Test Reactor (up to 10 MW) tokamaks. Advances on the technologies of heating, fueling, diagnostics, and materials supported these achievements. The successes have led to the initiation of the design phases of two tokamaks, the International Thermonuclear Experimental Reactor (ITER) and the US Toroidal Physics Experiment (TPX). ITER will demonstrate the controlled ignition and extended bum of D-T plasmas with steady state as an ultimate goal. ITER will further demonstrate technologies essential to a power plant in an integrated system and perform integrated testing of the high heat flux and nuclear components required to use fusion energy for practical purposes. TPX will complement ITER by testing advanced modes of steady-state plasma operation that, coupled with the developments in ITER, will lead to an optimized demonstration power plant.
Date: April 1, 1995
Creator: Sheffield, J. & Galambos, J.
Partner: UNT Libraries Government Documents Department

Progress in Compact Toroid Experiments

Description: The term "compact toroids" as used here means spherical tokamaks, spheromaks, and field reversed configurations, but not reversed field pinches. There are about 17 compact toroid experiments under construction or operating, with approximate parameters listed in Table 1.
Date: September 1, 2002
Creator: Dolan, Thomas James
Partner: UNT Libraries Government Documents Department

A Model of Plasma Rotation in the Livermore Spheromak for the Regimes of Large Connection Lengths

Description: A model is suggested that predicts the velocity and geometrical characteristics of the plasma rotation in the Livermore spheromak. The model addresses the ''good confinement'' regimes in this device, where the typical length of magnetic field lines before their intersection with the wall (this length is called ''connection length'' below) becomes large enough to make the parallel heat loss insignificant. In such regimes, the heat flux is determined by the transport across toroidally-averaged flux surfaces. The model is based on the assumption that, entering the good confinement regime, does not automatically mean that the connection length becomes infinite, and perfect flux surfaces are established. It is hypothesized that connection length remains finite, albeit large in regard to the parallel heat loss. The field lines are threading the whole plasma volume, although it takes a long distance for them to get from one toroidally-averaged flux surface to another. The parallel electron momentum balance then uniquely determines the distribution of the electrostatic potential between these surfaces. An analysis of viscous stresses shows that the toroidal flow is much faster than the poloidal flow. It is shown that the rotation shear usually exceeds by a factor of a few the characteristic growth rate of drift waves, meaning that suppression of the transport caused by the drift turbulence may occur, and a transport barrier with respect to this transport mechanism may be formed. The model may be useful for assessing the plasma rotation in other spheromaks and, possibly, reversed-field pinches and field-reversed configurations provided a certain set of applicability conditions (Sec. II) is fulfilled.
Date: January 3, 2007
Creator: Ryutov, D
Partner: UNT Libraries Government Documents Department

Design sensitivities and trade offs

Description: This paper contains viewgraphs on comparisons between INTOR-like tokamak reactors. Benchmark modes and optimization modes are discussed. Cost-benefit analysis is considered. (LSP)
Date: January 1, 1987
Creator: Reid, R.L.
Partner: UNT Libraries Government Documents Department

TPSS plasma engineering studies: profile effects and plasma power balance

Description: A computationally fast profile-averaged, steady-state plasma model has been developed to allow studies of radial effects in ignited and driven tokamak systems. This code was used to search for the smallest size tokamak consistent with power balance calculations. (MOW)
Date: January 1, 1985
Creator: Borowski, S.K. & Strickler, D.J.
Partner: UNT Libraries Government Documents Department

Impurity and particle control for INTOR

Description: The INTOR impurity control system studies have been focused on the development of an impurity control system which would be able to provide the necessary heat removal and He pumping while satisfying the requirements for (1) minimum plasma contamination by impurities, (2) reasonable component lifetime (approx. 1 year), and (3) minimum size and cost. The major systems examined were poloidal divertors and pumped limiters. The poloidal divertor was chosen as the reference option since it offered the possibility of low sputtering rates due to the formation of a cool, dense plasma near the collector plates. Estimates of the sputtering rates associated with pumped limiters indicated that they would be too high for a reasonable system. Development of an engineering design concept was done for both the poloidal divertor and the pumped limiter.
Date: February 1, 1985
Creator: Post, D.
Partner: UNT Libraries Government Documents Department

Fusion Engineering Device (FED) first wall/shield design

Description: The torus of the Fusion Engineering Device (FED) is comprised of the bulk shield and its associated spool lstructure and support system, the first wall water-cooled panel and armor systems, and the pumped limiter. The bulk shielding is provided by ten shield sectors that are installed in the spool structure in such a way as to permit extraction of the sectors through the openings between adjacent toroidal field coils with a direct radial movement. The first wall armor is installed on the inboard and top interior walls of these sectors, and the water-cooled panels are installed on the outboard interior walls and the pumped limiter in the bottom of the sectors. The overall design of the first wall and shield system is described in this paper.
Date: January 1, 1981
Creator: Sager, P.H.; Fuller, G.; Cramer, B.; Davisson, J.; Haines, J. & Kirchner, J.
Partner: UNT Libraries Government Documents Department

Optimization of a bundle divertor for FED

Description: Optimal double-T bundle divertor configurations have been obtained for the Fusion Engineering Device (FED). On-axis ripple is minimized, while satisfying a series of engineering constraints. The ensuing non-linear optimization problem is solved via a sequence of quadratic programming subproblems, using the VMCON algorithm. The resulting divertor designs are substantially improved over previous configurations.
Date: January 1, 1982
Creator: Hively, L.M.; Rothe, K.E. & Minkoff, M.
Partner: UNT Libraries Government Documents Department

Engineering considerations in the selection of the tokamak to follow the Tokamak Fusion Test Reactor (TFTR)

Description: The tokamak to follow the Tokamak Fusion Test Reactor (TFTR) should satisfy two important objectives. First, it should be a significant step in physics and engineering goals in order to maintain the level of progress which the US has established as the world leader in fusion energy development. The second objective should be to provide the information necessary to support the strategy and goals of the long-range Department of Energy (DOE) Fusion Program. In their Comprehensive Program Management Plan, the DOE identifies the need for a reactor technology program in the 1990s in which the major goal is to prove engineering feasibility. In this paper, the specific engineering needs are identified which have been developed through the tokamak design studies over the past decade. On the basis of these needs, it appears that several options are available for the next tokamak to follow TFTR. The final choice of the concept will involve consideration of the technical needs and the reality of the Fusion Program budget.
Date: January 1, 1983
Creator: Shannon, T.E.
Partner: UNT Libraries Government Documents Department