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PLT toroidal field coil power tests

Description: The PLT toroidal field coil power tests were initiated in October, 1974 to gain information in several areas. The most important objectives during the tests were the verification of deflections and stresses as predicted by Frankenberg and Smith. Also, the stability of the toroidal field coils against radial self-field loading was to be determined. Lastly, the predicted thermal characteristics of the coils were to be verified. (auth)
Date: November 1, 1975
Creator: Marino, R.; Citrolo, J. & Frankenberg, J.
Partner: UNT Libraries Government Documents Department

Analytic solutions for constant tension coil shapes

Description: An analytical solution of the differential equation describing the shape of a flexible filamentary conductor (incapable of supporting bending stresses) in a toroidal magnetic field has been obtained. The solution derives from a series expansion of modified Bessel functions of integer order. The characteristics of toroidal field magnets for proposed tokamak devices are obtainable by term by term integration of the solution series. General expressions are given for the following coil characteristics: the conductor turn length, the solenoid inductance, the area enclosed by the coil and the coil support dimensions. For several particular cases of interest these coil characteristics are obtained as closed form analytical formula. (auth)
Date: January 1, 1976
Creator: Gralnick, S.L. & Tenney, F.H.
Partner: UNT Libraries Government Documents Department

Design and fabrication of the PDX poloidal field solenoid utilizing fiberglass reinforced epoxy

Description: This paper discusses the basic design of the Poloidal Field Solenoid Coil. It will be mainly concerned with the more unique features of the Solenoid such as the copper coil windings and the design of the epoxy-glass structural support mandrels. The center solenoid coil of the PDX machine consists of five different coil systems (OH No. 8, No. 9; NF No. 11; DF No. 7; EF Solenoid and CF No. 9). Three concentric fiberglass reinforced epoxy cylinders fabricated in- house will act as mandrels to support and to house the coils that will result as an integral unit. (auth)
Date: November 1, 1975
Creator: Young, K.S.C.
Partner: UNT Libraries Government Documents Department

Structural safety features for superconducting magnets

Description: A survey has been carried out for various potential structural safety problems of superconducting fusion magnets. These areas include: (1) Stresses due to inhomogeneous temperature distributions in magnets where normal regions have been initiated. (2) Stress distributions and yield forces due to cracks and failed regions. (3) Superconducting magnet response due to seismic excitation. These analyses have been carried out using a variety of large capacity finite element computer codes that allow for the evaluation of stresses in elastic or elastic-plastic zones and around singularities in the magnet structure. Thus far, these analyses have been carried out on UWMAK-I type magnet systems. (auth)
Date: January 1, 1975
Creator: Lehner, J.; Reich, M.; Powell, J.; Bezler, P.; Gardner, D.; Yu, W. et al.
Partner: UNT Libraries Government Documents Department

Mechanical design of a 250 kilogauss solenoidal magnet

Description: The mechanical design and construction of a 5 cm bore, 23 cm long solenoidal magnet operated at 250 kilogauss is described. The magnet provides confining field for a plasma heated by a CO$sub 2$ laser. Radial diagnostic ports with a clear aperture of 0.41 cm allow viewing access near the magnet midplane. The on-axis field homogeneity is within 5 percent over a central length of 12 cm. The magnet sustained 500 to 1000 pulses at the highest field levels before catastrophic failure. (auth)
Date: December 1, 1975
Creator: Bonanos, P.
Partner: UNT Libraries Government Documents Department

PDX vacuum vessel stress analysis

Description: A stress analysis of PDX vacuum vessel is described and the summary of results is presented. The vacuum vessel is treated as a toroidal shell of revolution subjected to an internal vacuum. The critical buckling pressure is calculated. The effects of the geometrical discontinuity at the juncture of toroidal shell head and cylindrical outside wall, and the concavity of the cylindrical wall are examined. An effect of the poloidal field coil supports and the vessel outside supports on the stress distribution in the vacuum vessel is determined. A method evaluating the influence of circular ports in the vessel wall on the stress level in the vessel is outlined. (auth)
Date: January 1, 1975
Creator: Nikodem, Z.D.
Partner: UNT Libraries Government Documents Department

Summary of existing superconducting magnet experience and its relevance to the safety of fusion magnet

Description: A comprehensive summary of experience with over twenty superconducting magnet systems has been collected through visits to and discussions about existing facilities including, for example, the bubble chamber magnets at Brookhaven National Laboratory, Argonne National Laboratory and Fermi National Accelerator Laboratory, and the large superconducting spectrometer at Stanford Linear Accelerator Center. This summary includes data relating to parameters of these magnets, magnet protection methods, and operating experiences. The information received is organized and presented in the context of its relevance to the safe operation of future, very large superconducting magnet systems for fusion power plants. (auth)
Date: January 1975
Creator: Hsieh, S. Y.; Allinger, J.; Danby, G.; Keane, J.; Powell, J. & Prodell, A.
Partner: UNT Libraries Government Documents Department

Superconducting coil protection

Description: The protection system is based on a two-phase construction program. Phase I is the development of a reliable hardwired relay control system with a digital loop utilizing firmware and a microprocessor controller. Phase II is an expansion of the digital loop to include many heretofore unmonitored coil variables. These new monitored variables will be utilized to establish early quench detection and to formulate confirmation techniques of the quench detection mechanism. Established quench detection methods are discussed and a new approach to quench detection is presented. The new circuit is insensitive to external pulsed magnetic fields and the associated induced voltages. Reliability aspects of the coil protection system are discussed with respect to shutdowns of superconducting coil systems. Redundance and digital system methods are presented as related topics. (auth)
Date: January 1, 1975
Creator: Woods, E.L.
Partner: UNT Libraries Government Documents Department

Optimization of the ECT background coil

Description: This study was begun to optimize the Eccentric Coil Test (ECT) background coil. In the course of this work a general optimization code was obtained, tested, and applied to the ECT problem. So far this code has proven to be very satisfactory. The results obtained with this code and earlier codes have illustrated the parametric behavior of such a coil system and that the optimum for this type system is broad. This study also shows that a background coil with a winding current density of less than 3000 A/cm$sup 2$ is not feasible for the ECT models presented in this paper. (auth)
Date: January 1, 1975
Creator: Ballou, J. K. & Luton, J. N.
Partner: UNT Libraries Government Documents Department

Magnetic field shielding system in a tokamak experimental power reactor (EPR): concept and calculations

Description: A poloidal magnetic field shielding system is proposed for a tokamak EPR. This coil system minimizes the pulsed poloidal field that intersects the TF (toroidal field) coils and hence reduces the risk of superconductor quenching and structural failure of the coils. Based on an idealized shielding model, we have determined the configurations for the OH (ohmic heating), the S-VF (shield- vertical field), and the T-VF (trimming-vertical field) coils in a typical tokamak EPR. It is found that the pulsed poloidal field strength is greatly reduced in the TF coil region. The overall requirement in stored plasma and vertical field energy is also substantially reduced when compared with conventional EPR designs. Use of this field shielding system is expected to enhance reliability of the superconducting TF coils in a tokamak EPR. (auth)
Date: January 1, 1975
Creator: Peng, Y.K.M.; Marcus, F.B.; Dory, R.A. & Moore, J.R.
Partner: UNT Libraries Government Documents Department

Energy system for the generation of divertor magnetic fields in the PDX fusion research device

Description: One of the major problems encountered in the development of Tokamak type fusion reactors is the presence of impurities in the plasma. The PDX device is designed to study the operation of poloidal magnetic field divertors and consequent magnetic limiters for controlling and reducing the amount of impurities. A system of coils placed at specific locations produces a required field configuration for the poloidal divertor. This paper describes the system of energy supplies required and the interrelations of field coil currents during plasma current initiation, growth and steady state. (auth)
Date: January 1, 1975
Creator: Turitzin, N.M.
Partner: UNT Libraries Government Documents Department

Letter report for the superconducting magnet development program, September 1, 1975--December 1, 1975

Description: Brief discussions are given on the following topics: (1) program objectives, (2) implementation of the program, (3) program Staff as of 1 Dec. 1975, (4) subprogram reports, (5) list of major purchases, (6) list of new proposals under consideration, and (7) visitors. (auth)
Date: February 1, 1976
Partner: UNT Libraries Government Documents Department

Elastic stability and vibration of toroidal magnets for fusion reactors. Final report

Description: The vibration and elastic stability of a set of discrete superconducting toroidal field magnets arranged to form a ''bumpy'' torus is examined. The mutual destabilizing magnetic forces between magnet pairs are calculated using a numerical differential inductance technique. It is shown that the mutual attractive magnetic forces can produce elastic buckling of the entire toroidal set. The vibration modes of the set are also found as functions of the coil current. The response of the set of magnets to an earthquake type motion of the toroidal base is calculated. The calculations have been incorporated in a computer code which accompanies the report. Measurements are made of the lateral stiffness of a flexible, planar, superconducting coil between two rigid coils in series. These tests show a dramatic decrease in the natural bending frequency with subsequent elastic instability or ''buckling'' at a critical value of the current in the coils. These observations support a magnetoelastic analysis which shows that proposed designs, of toroidal field coils for Tokamak fusion reactors, have insufficient lateral support for mechanical stability of the magnets. (auth)
Date: September 1, 1975
Creator: Moon, F.C. & Swanson, C.
Partner: UNT Libraries Government Documents Department

Toroidal field coils for the PDX machine

Description: This paper describes the engineering design features of the TF coils for the PDX machine. Included are design details of the electrical insulation, water cooling, and coil segment joint which allows access to the central machine area. A discussion of the problems anticipated in the manufacture and the planned solutions are presented. (auth)
Date: January 1, 1975
Creator: Bushnell, C.W.
Partner: UNT Libraries Government Documents Department

Center column design of the PLT

Description: The center column of the PLT machine is a secondary support member for the toroidal field coils. Its purpose is to decrease the bending moment at the nose of the coils. The center column design was to have been a stainless steel casting with the toroidal field coils grouped around the casting at installation, trapping it in place. However, the castings developed cracks during fabrication and were unsuitable for use. Installation of the coils proceeded without the center column. It then became necessary to redesign a center column which would be capable of installation with the toroidal field coils in place. The final design consists of three A-286 forgings. This paper discusses the final center column design and the influence that new knowledge, obtained during the power tests, had on the new design. (auth)
Date: January 1, 1975
Creator: Citrolo, J. & Frankenberg, J.
Partner: UNT Libraries Government Documents Department

Application data for the PLT stabilizing field rectifier

Description: This paper describes the 12-pulse stabilizing field rectifier used for vertical field production in the Princeton Large Torus (PLT). It is essential that the rectifier be reliable, and protect itself from all faults including induced transient overvoltage produced by switching and plasma instabilities. To this end, computer simulations were run to insure protection under various fault conditions. (auth)
Date: November 1, 1975
Creator: Bronner, G.; Murray, J.G. & Oliaro, G.E.
Partner: UNT Libraries Government Documents Department

Superconducting magnet development program progress report, July 1974--June 1975

Description: During FY 1975, the superconducting magnet development program at the Lawrence Livermore Laboratory was primarily directed toward the development of multifilamentary Nb$sub 3$Sn conductor for large CTR machines. It was secondarily concerned with preliminary work for the MX experiment and with the acquisition of additional testing facilities. Among the significant achievements was the construction and operation of a 27-cm-bore coil to its short-sample limit of 7-T at the windings. The coil was wound with a 100-m length of 67,507- filament Nb$sub 3$Sn conductor. (auth)
Date: October 24, 1975
Creator: Cornish, D.N.; Harvey, A.R.; Nelson, R.L.; Taylor, C.E. & Zbasnik, J.P.
Partner: UNT Libraries Government Documents Department

Uncertainties in calculated heating and radiation damage in the toroidal field coil of a tokamak experimental power reactor due to neutron cross-section errors

Description: Calculated results are presented of the uncertainties in the neutron scalar flux, the energy deposition per unit volume, and the displacements per atom in the toroidal field coil of a tokamak experimental power reactor due to neutron cross-section errors in iron and carbon which are major constituents of the blanket-shield-coil configuration considered. The calculations were carried out using perturbation theory to obtain sensitivity profiles for the various cross sections of interest, and these profiles were then combined with cross- section error estimates, including correlations, to obtain the uncertainties. Each of the three responses--the neutron scalar flux, the energy deposition per unit volume, and the displacements per atom--is found to be very sensitive to the cross sections in the energy group which contains the source (approximately 14 MeV since a D-T source is assumed), and each of the responses is found to have a relative standard deviation of approximately 100 percent due to neutron cross- section errors in iron.
Date: March 1, 1976
Creator: Alsmiller, R.G. Jr.; Barish, J. & Weisbin, C.R.
Partner: UNT Libraries Government Documents Department

Scaling relations for eddy current phenomena

Description: Formulas are given for various electromagnetic quantities for coils in the presence of conductors, with the scaling parameters factored out so that small-scale model experiments can be related to large-scale apparatus. Particular emphasis is given to such quantities as eddy current heating, forces, power, and induced magnetic fields. For axially symmetric problems, closed-form integrals are available for the vector potential and all the other quantities obtainable from it. For unsymmetrical problems, a three-dimensional relaxation program can be used to obtain the vector potential and then the derivable quantities. Data on experimental measurements are given to verify the validity of the scaling laws for forces, inductances, and impedances. Indirectly these also support the validity of the scaling of the vector potential and all of the other quantities obtained from it. (auth)
Date: November 1, 1975
Creator: Dodd, C.V. & Deeds, W.E.
Partner: UNT Libraries Government Documents Department

Toroidal field coils for the Princeton Divertor Experiment

Description: The toroidal field coils for the Princeton Divertor Experiment (PDX) and their supporting structure are described. The special demountable nature of the coils and the problems which result from this feature are discussed. The procedures for assembly and fabrication of the coils are presented. (auth)
Date: October 1, 1975
Creator: Citrolo, J.C. & Bushnell, C.W.
Partner: UNT Libraries Government Documents Department

Magnetic braiding due to weak asymmetry

Description: Magnetic surfaces for a plasma with a helical current perturbation approximately epsilon$sup 2$ are destroyed by toroidal effects or by a second current perturbation, of incommensurate helicity, and the behavior of magnetic field lines becomes stochastic in layers of relative width epsilon$sup -$/sup l/ exp (-$pi$/2 epsilon). (auth)
Date: January 1, 1976
Creator: Rechester, A.B. & Stix, T.H.
Partner: UNT Libraries Government Documents Department

Calculation of electromagnetic fields and forces in coil systems of arbitrary geometry

Description: A computer program, EFFI, is described which calculates the electric and magnetic fields due to an arbitrary spatial distribution of current-carrying circular loops, circular arcs, and straight lines. The electric field is assumed to arise solely from the time variation of the magnetic field, and the magnetic field due to the changing electric field is assumed to be negligible. In addition, the conductor bundle elements (loops, arcs, lines) are assumed to be absent. Electric and magnetic flux lines and magnetic forces and inductances are also calculated by the program. The algorithm used in the code, which is based on a combination of direct and numerical integration using the Biot-Savart law, is discussed. The methods used to maintain accuracy in calculating fields within the conductor bundle, in particular, are detailed. Several examples are then presented to illustrate the input and output features as well as the accuracy obtained and the running time required. (auth)
Date: November 14, 1975
Creator: Sackett, S.J.
Partner: UNT Libraries Government Documents Department