skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Structural design of the superconducting Poloidal Field coils for the Tokamak Physics Experiment

Abstract

The Tokamak Physics Experiment concept design uses superconducting coils made from cable-in-conduit conductor to accomplish both magnetic confinement and plasma initiation. The Poloidal Field (PF) magnet system is divided into two subsystems, the central solenoid and the outer ring coils, the latter is focus of this paper. The eddy current heating from the pulsed operation is excessive for a case type construction; therefore, a ``no case`` design has been chosen. This ``no case`` design uses the conductor conduit as the primary structure and the electrical insulation (fiberglass/epoxy wrap) as a structural adhesive. The model integrates electromagnetic analysis and structural analysis into the finite element code ANSYS to solve the problem. PF coil design is assessed by considering a variety of coil current wave forms, corresponding to various operating modes and conditions. The structural analysis shows that the outer ring coils are within the requirements of the fatigue life and fatigue crack growth requirements. The forces produced by the Toroidal Field coils on the PF coils have little effect on the maximum stresses in the PF coils. In addition in an effort to reduce the cost of the coils new elongated PF coils design was proposed which changes the aspect ratiomore » of the outer ring coils to reduce the number of turns in the coils. The compressive stress in the outer ring coils is increased while the tensile stress is decreased.« less

Authors:
;
Publication Date:
Research Org.:
Lawrence Livermore National Lab., CA (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
10125308
Report Number(s):
UCRL-JC-114266; CONF-931018-84
ON: DE94007078; TRN: 94:004578
DOE Contract Number:
W-7405-ENG-48; AC02-76CH03073
Resource Type:
Conference
Resource Relation:
Conference: Symposium on fusion engineering,Hyannis, MA (United States),11-15 Oct 1993; Other Information: PBD: 6 Oct 1993
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; SUPERCONDUCTING COILS; COMPUTER-AIDED DESIGN; TOKAMAK DEVICES; MECHANICAL STRUCTURES; FINITE ELEMENT METHOD; A CODES; 700430; MAGNET COILS AND FIELDS

Citation Formats

O`Connor, T.G., and Zbasnik, J.P.. Structural design of the superconducting Poloidal Field coils for the Tokamak Physics Experiment. United States: N. p., 1993. Web.
O`Connor, T.G., & Zbasnik, J.P.. Structural design of the superconducting Poloidal Field coils for the Tokamak Physics Experiment. United States.
O`Connor, T.G., and Zbasnik, J.P.. Wed . "Structural design of the superconducting Poloidal Field coils for the Tokamak Physics Experiment". United States. doi:. https://www.osti.gov/servlets/purl/10125308.
@article{osti_10125308,
title = {Structural design of the superconducting Poloidal Field coils for the Tokamak Physics Experiment},
author = {O`Connor, T.G. and Zbasnik, J.P.},
abstractNote = {The Tokamak Physics Experiment concept design uses superconducting coils made from cable-in-conduit conductor to accomplish both magnetic confinement and plasma initiation. The Poloidal Field (PF) magnet system is divided into two subsystems, the central solenoid and the outer ring coils, the latter is focus of this paper. The eddy current heating from the pulsed operation is excessive for a case type construction; therefore, a ``no case`` design has been chosen. This ``no case`` design uses the conductor conduit as the primary structure and the electrical insulation (fiberglass/epoxy wrap) as a structural adhesive. The model integrates electromagnetic analysis and structural analysis into the finite element code ANSYS to solve the problem. PF coil design is assessed by considering a variety of coil current wave forms, corresponding to various operating modes and conditions. The structural analysis shows that the outer ring coils are within the requirements of the fatigue life and fatigue crack growth requirements. The forces produced by the Toroidal Field coils on the PF coils have little effect on the maximum stresses in the PF coils. In addition in an effort to reduce the cost of the coils new elongated PF coils design was proposed which changes the aspect ratio of the outer ring coils to reduce the number of turns in the coils. The compressive stress in the outer ring coils is increased while the tensile stress is decreased.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Oct 06 00:00:00 EDT 1993},
month = {Wed Oct 06 00:00:00 EDT 1993}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • The Tokamak Physics Experiment (TPX) will have a poloidal field system capable of full inductive operation poloidal for approximately a 20-s flattop and, with superconducting toroidal and poloidal field coils and non-inductive current drive, it will be capable of true steady-state operation. The poloidal field design is based on the ideal MHD equilibrium model as implemented in the TEQ code developed at LLNL. The PF coils are arranged in an up-down symmetric configuration, external to the TF coils. The TPX diverted plasma will have an aspect ratio of 4.5 and is highly shaped with a nominal elongation of 2 andmore » triangularity of approximately 0.8 as measured at the separatrix. The tokamak design is based on a high-current (q{sub {psi}}=3) plasma scenario and a low current scenario. Each scenario has an operational flexibility requirement which is defined as a region of plasma pressure and inductivity ({beta}{sub N} {minus} l{sub i}) space, where the plasma shape is constrained to keep the divertor configuration operational. Single-null plasma configurations are feasible, even with the same divertor hardware, by operating the PF coils asymmetrically. Recently applied optimization techniques have improved the capability of the PF system without additional cost.« less
  • A new-type Poloidal Field (PF) Coil power supply for future Tokamak reactors, aimed at removing the disturbance to the utility power system and reducing the power supply capacity, is proposed. PF power supply requires reductions of the capacity and the enormous regenerative power, by introducing a superconducting coil to the power supply. The new scheme of the circuit is described. After analyzing the start-up scenario of ITER, the concept of the new system is demonstrated.
  • Poloidal field (PF) coils in tokamaks are required to induce and initially heat the plasma as well as to stabilize it in an equilibrium position. The primary need for superconducting PF coils of subdivided high currents cable is to minimize the charging and discharging voltages and to reduce the ac losses during pulsing cycles. In this paper, pulsed coils developed or under development are briefly described to realize that the present effort is insufficient for the design of near future tokamak reactors.
  • The protection problems of superconducting coils in a large tokamak device are delineated. Effects of the plasma discharge on the first wall, the induced voltage, and the temperature rise during the quench of a superconducting coil, as well as the mechanical load on coils due to their mutual interaction under normal or fault conditions, are discussed. Various design choices and protection schemes are used to ensure the integrity of the coils during quench. For the Oak Ridge EPR design, a scheme of connecting symmetrically-located toroidal field coils in groups and isolating and discharging the fault coil only gives satisfactory results.
  • The protection problems of superconducting coils in a large tokamak device are delineated. Effects of the plasma discharge on the first wall, the induced voltage, and the temperature rise during the quench of a superconducting coil, as well as the mechanical load on coils due to their mutual interaction under normal or fault conditions, have been studied. Various design choices and protection schemes are used to ensure the integrity of the coils during quench. For the Oak Ridge Experimental Power Reactor design, a scheme of connecting symmetrically located toroidal field coils in groups isolates and discharges the fault coil only,more » giving satisfactory results.« less