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Current Averaging and Coil Segmentation in the Protection of Large Toroidal Superconducting Magnet Systems

  • H. T. Yeh
  • J. N. Luton
  • J. E. Simpkins
Part of the Advances in Cryogenic Engineering book series (ACRE, volume 21)

Abstract

Table I compares several designs of the superconducting toroidal magnet arrays required to confine the plasma in a large fusion Tokamak device [1–3]. Because of the high magnetic field and large plasma volume required in a power reactor, the magnetic energy stored in the toroidal field is very large. In order to avoid quenching—whether it is due to flux jumps, conductor motion, or other causes— before the design current is reached, cryostatic stabilization is usually preferred. Although there are some advantages, from the viewpoint of coil protection, to having a large number of coils in the torus, the actual number will probably be determined by factors such as field ripple in the plasma, manufacturing cost, access space, etc.
Table I

Comparison of Toroidal Field Coil Parameters in Various Power Reactor Designs

 

This work

UWMAK-I[1]

ORNL(1971)[2]

Princeton [3]

Number of coils

24

12

48

48

Conductor

NbTi-Cu

NbTi-Cu

NbTi-Cu

Nb3Sn

Stabilization

Cryostatic

Cryostatic

Cryostatic

Dynamic

Major radius, m

10

13

10.5

10.5

Central field

4

3.82

3.7

6

Maximum field in winding, T

8

8.66

8

16

Coil shape

Circular

D

Circular

D

Inner diameter, m

10

12.2, 20

11.2

12,19

Operating current, A

5000

10,212

5000

10,000s

Average current density

    

in winding, 107 x A/m2

1.7

1.318

1.55

2.1

Energy stored in torus,

    

1010 J

3.367

28

4

25

† Average current density in conductor.

The use of twenty-four coils seems to represent a plausible compromise of these factors. Because of the close proximity of a large number of coils, the inductive coupling plays a rather important role in the electrical behavior ofz the coils of such a close-packed toroidal array.

Keywords

Circuit Breaker Current Average External Resistor Toroidal Field Hall Probe 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    University of Wisconsin Fusion Feasibility Study Group, “A Wisconsin Toroidal Fusion Reactor Design” (UWMAK-I), University of Wisconsin, Madison, Wisconsin (1974).Google Scholar
  2. 2.
    M. S. Lubell, W. F. Gauster, K. R. Efferson, A. P. Fraas, H. M. Long, J. N. Luton, C. E. Parker, D. Steiner, and W. C. T. Stoddart, IAEA III:433 (1971).Google Scholar
  3. 3.
    R. G. Mills (ed.), A Fusion Power Plant, MATT-1050, Princeton University, Plasma Physics Laboratory (1974).Google Scholar
  4. 4.
    P. N. Haubenreich and M. Roberts (eds.), “ORMAK F/BX, A Tokamak Fusion Test Reactor,” ORNL-TM4634 (1974).Google Scholar
  5. 5.
    J. File, in: A Fusion Power Plant (R. G. Mills, ed.), MATT-1050, Princeton University, Plasma Physics Laboratory (1974), Chap. 13.Google Scholar
  6. 6.
    B. J. Maddock and G. B. James, in: Proc. IEE 115:543 (1968).Google Scholar

Copyright information

© Springer Science+Business Media New York 1960

Authors and Affiliations

  • H. T. Yeh
    • 1
  • J. N. Luton
    • 1
  • J. E. Simpkins
    • 1
  1. 1.Thermonuclear DivisionOak Ridge National LaboratoryOak RidgeUSA

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