JPS596486B2 - Superconducting coil manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing large-sized superconducting coils used in nuclear fusion devices, energy storage devices, and the like.

The use of superconducting coils as a component of energy storage devices and magnetic field generators for nuclear fusion reactors is being considered, but the size of superconducting coils is gigajoule (GJ=109 J) or larger.

FIG. 1 is a partially cutaway perspective view of a pancake-shaped superconducting coil, which is a type of large-sized superconducting coil. It has a structure in which a plurality of superconducting wires 2 are stacked and fixed in a winding frame 5 via interlayer spacers 4.
Both the turns and layers are electrically insulated by interturn spacers 3 and interlayer spacers 4, and interlayer spacers 4 form gaps 6 through which a cooling medium such as liquid helium flows. This gap 6 has the role of allowing air bubbles of the cooling medium generated on the surface of the superconducting wire 2 to escape, and the role of supplying the cooling medium. FIG. 2 is a cross-sectional view of a disk-shaped superconducting coil, which is a type of large superconducting coil. In this superconducting coil 1, a plurality of coil grooves 8 are formed on both sides of a plate-shaped holding member 1 made of metal or an insulator. A superconducting disk 2 formed by providing a coil groove and storing a superconducting wire 2 in the coil groove.
It is assembled by stacking a plurality of 00 and tightening them with bolts 9 and nuts 10.

The disk-shaped superconducting coil 1 includes a circular coil 1 shown in FIG. 3a, similar to the pancake-shaped superconducting coil shown in FIG.
This is the racetrack coil 1 shown in FIG. b or the D-type coil 1 shown in FIG. 3c (7). A solder type superconducting wire is considered to be optimal as the large current capacity superconducting wire 2 used in these large superconducting coils.

FIGS. 4a and 4b are perspective views of solder-type superconducting wires, in which an aggregate 14 of a plurality of superconducting strands 13 is placed in a groove 12 cut in a normal-conducting metal base material 11 with solder (metallic material such as Pb-Sn). It is configured to be fixed by an adhesive 15.

The normally conductive metal base material 11 is made of copper or aluminum, which has a low electrical resistivity at extremely low temperatures (for example, liquid helium temperature of 4.2), and copper is currently often used.

The superconducting wire 13 may be a superconductor itself such as Nb-Ti or Nb3Sn, but it may also be a superconductor coated with copper or aluminum, or an ultra-fine superconductor in which multiple superconducting filaments are embedded in a normal conductive metal such as copper. It may be a multicore superconducting wire or an ultrafine multicore twisted superconducting wire in which the superconducting filament is twisted and embedded in a normal conducting metal. The superconducting strand assembly 14 is produced by rolling a hollow stranded wire in which the superconducting strands 13 are arranged on the same circumference in cross section, as shown in a perspective view in FIG. 5a, for example. A flat aggregate 14 as shown in b can be easily obtained.

Although the above-mentioned aggregate 14 is a band-shaped twisted wire, a band-shaped braided wire may be used instead of the band-shaped twisted wire.

Note that although the superconducting wire 2 shown in FIG. 4 is provided with a groove 12, it is a superconducting wire in which a superconducting wire assembly 14 is fixed with solder to the side surface of a rectangular normal-conducting metal substrate 11 without a groove. It can also be used.

Next, a conventional method for manufacturing superconducting coils will be described. Solder 1 superconducting wire 13 into groove 12 of normal conductive metal base material 11
A superconducting coil 1 is formed by winding the superconducting wire 2 manufactured by fixing the superconducting wires 5 into the shape shown in FIG.
The bending of the superconducting wire during coil winding is a flat twist in the pancake-shaped superconducting coil shown in FIG. 1, and an edge twist in the disk-shaped superconducting coil shown in FIG. The superconducting coil 1 used in energy storage devices and nuclear fusion reactors is gigantic and has an energy of more than gigajoules.
The superconducting wire 2 wound around this has large dimensions, for example, outer dimensions of 10 mf and 60 mu, which can carry a large current, for example, 30,000 amperes. When winding such a large superconducting wire 2 into the shape shown in Fig. 3, if the minimum bending radius of the coil is 1 m, for example, 0.5 (f) for a flat weiss and 3 (f) for an edge weiss. (
:f) distortion occurs in the superconducting wire 2.

Distortion is particularly large in edge-weiss bending. This distortion of the superconducting wire during coil winding greatly reduces the superconducting current capacity of the superconducting wire 13, which is a basic component of the superconducting wire 2, and as a result, the magnetic field created by the superconducting coil 1 is lower than the design value. It can be significantly reduced.

In particular, when the superconductor is a compound such as Nb3Sn, the deterioration of superconducting properties is significant. This invention was made in order to eliminate the drawbacks of the conventional method of manufacturing a superconducting coil as described above, and when the superconducting wire 2 is deformed by winding, the solder 15 is in a molten state. By avoiding the addition of strain to the superconducting strands 13, it is possible to provide a large superconducting coil that is used in energy storage devices and nuclear fusion reactors without deteriorating its superconducting properties.

FIG. 6 shows an embodiment of the method for manufacturing a superconducting coil according to the present invention.

The superconducting wire 2 supplied from the wire drum 16 is wound around a coil former 17 and formed into a coil. Coil winding form 1
A heating device 18 is provided adjacent to the superconducting wire 7 to heat the superconducting wire 2 so that the superconducting wire 2 is wound onto a coil former while keeping the solder 15, which is a component thereof, in a molten state. In this way, even if the superconducting wire 2 is deformed by winding, the superconducting wire 13, which is a component thereof, will not be distorted at all. This is because the solder 15 in a molten state has completely lost its adhesion, so the superconducting wires 13 are not bonded to each other, or the superconducting wires and the normal conductive metal base 11 are not bonded and the superconducting wires are not bonded to each other. This is because the line assembly 14 can be freely deformed. The superconducting wire that has been wound into a coil former and has finished its deformation is cooled naturally or, if necessary, forcedly cooled to solder 15.
solidifies again, regains its adhesion, and returns to its original state as a superconducting wire. As described above, according to the present invention, since it is impossible to generate the distortion that occurs when the superconducting wire 13 is wound while being fixed to the normal conductive metal base material 11, it is possible to create a superconducting coil without deterioration of superconducting properties. can be provided.

Although FIG. 6 shows the case of manufacturing the circular coil shown in FIG. 3a, the racetrack coil shown in FIG. 3b,
The invention can be applied as is to the production of the COD type coil shown in FIG. 3 or the pancake type coil shown in FIG.

It goes without saying that the heating device may be a heating furnace using a normal heater, or other induction heating devices or a method such as electrical heating in which a current is passed through an appropriate portion of the superconducting wire. In the above-mentioned superconducting coil, the superconducting wire 2 was passed through the heating device 18 and wound around the coil winding die 17, but the superconducting wire 2 can also be wound into a substantially coil shape and then formed into a superconducting coil.

This method is particularly effective for disk-shaped superconducting coils. As described above, according to the present invention, in manufacturing a superconducting coil formed by winding solder-type superconducting wire, the solder is kept in a molten state when the superconducting wire is deformed by winding, so that the superconducting A large superconducting coil can be manufactured without strain being applied to the strands and without deterioration of superconducting properties.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway view of a pancake-shaped superconducting coil, Figure 2
3 is a perspective view showing the shape of the superconducting coil, FIG. 4 is a perspective view of a solder-type superconducting wire, and FIG. 5 is a perspective view showing stranded wires and strip-shaped stranded wires.
FIG. 6 is a diagram showing an embodiment of the superconducting coil manufacturing method of the present invention.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a superconducting coil comprising winding a superconducting wire in which a superconducting wire is fixed with a metallic adhesive on the surface of a normal-conducting metal base material, wherein the superconducting wire is heated to form the metallic material. A method for manufacturing a superconducting coil, characterized in that the adhesive is wound in a molten state. 2. A method for manufacturing a superconducting coil in which a superconducting wire having a superconducting wire fixed to the surface of a normal-conducting metal base material with a metallic adhesive is wound, the superconducting wire being heated to melt the metallic adhesive. 1. A method for manufacturing a superconducting coil, comprising: winding the superconducting coil into a substantially coil shape, and then forming the coil into a predetermined coil shape.