Superconducting cable, coil, cable structure, and nuclear fusion reactor

Abstract

A superconducting cable (10) includes: a plurality of flexible superconductors (11) that are stacked in a stacking direction orthogonal to the extending direction of the superconducting cable (10); at least one flexible first reinforcing wire (21) that extends in the extending direction of the superconducting cable (10) and that overlaps the plurality of superconductors (11) in the stacking direction; a first securing member (30A) that holds a first held portion (21a), which is a portion of the first reinforcing wire (21) in the extending direction of the superconducting cable (10); and a second securing member (30B) that holds a second held portion (21a), which is another portion of the first reinforcing wire (21) in the extending direction of the superconducting cable (10). According to this structure, hoop stress acting on the superconductors (11) can be reduced by the first reinforcing wire (21).

Description

Superconducting Cable, Coil, Cable Structure, and Fusion Reactor

[0001] The present disclosure relates to a superconducting cable, a coil, a cable structure, and a fusion reactor.

[0002] Patent Documents 1 and 2 below disclose a superconducting cable applicable to the coils of a fusion reactor. This superconducting cable has a plurality of stacked superconductors. When forming a coil with the superconducting cable, it is necessary to bend the superconducting cable along the shape of the coil. In Patent Documents 1 and 2, a positional deviation of the plurality of superconductors in their stretching direction is allowed, and thereby the flexibility of the superconducting cable is obtained.

[0003] Japanese Unexamined Patent Application Publication No. 2019-102298 Japanese Unexamined Patent Application Publication No. 2024-011246

[0004] When an electric current flows through the coil, a Lorentz force directed outward in the radial direction acts on the superconductor. And a tensile force (hoop stress) caused by this Lorentz force acts on the superconductor. If the hoop stress becomes excessive, there is a concern about damage to the superconductor.

[0005] (1) An example of the superconducting cable proposed in the present disclosure includes a plurality of superconductors each extending in a first direction, laminated in a second direction orthogonal to the first direction, and having flexibility; at least one first reinforcing wire extending in the first direction, overlapped with the plurality of superconductors in the second direction, and having flexibility; a first fixing member holding a first held portion that is a part of the reinforcing member in the first direction; and a second fixing member holding a second held portion that is another part of the reinforcing member in the first direction.

[0006] According to this structure, by fixing the positions of the two fixing members, the elongation of the superconducting cable between them can be suppressed. As a result, the tensile stress (hoop stress) acting on the superconductor can be reduced.

[0007] (2) Another example of a superconducting cable proposed in this disclosure comprises a plurality of flexible superconductors, each extending in a first direction and stacked in a second direction perpendicular to the first direction; at least one flexible first reinforcing wire, extending in the first direction and superimposed on the plurality of superconductors in the second direction; and a plurality of protective members, each formed in a tubular shape, surrounding the plurality of superconductors and the at least one reinforcing wire, and aligned in the first direction.

[0008] This structure allows the movement of the superconductor inside the protective member (movement of the superconductor due to the Lorentz force) to be suppressed by the first reinforcing wire. As a result, the hoop stress acting on the superconductor can be reduced.

[0009] This is a perspective view showing an example of the superconducting cable proposed in this disclosure. This is a perspective view of the superconducting cable shown in Figure 1A from a different angle. This is an exploded perspective view of the superconducting cable. This is a cross-sectional view along the line IIIa-IIIa shown in Figure 1A. This is a cross-sectional view along the line IIIb-IIIb shown in Figure 1B. This is a cross-sectional view along the line IV-IV shown in Figure 1A. This is a schematic diagram showing an enlarged cross-section of the superconducting tape depicted in Figure 3A. This is a diagram showing an example of a cable structure including the superconducting cable proposed in this disclosure. In this structure, the superconducting tape is drawn out from the superconducting cable. This is an exploded perspective view of the cable structure shown in Figure 6. This is a cross-sectional view along the line VI-VI shown in Figure 6. This is a schematic diagram showing an enlarged cross-section of the superconducting tape depicted in Figure 8. This is a diagram showing another example of a cable structure including the superconducting cable proposed in this disclosure. In this structure, two superconducting cables are connected. This is an exploded view of the cable structure shown in Figure 10. This is an exploded perspective view of the superconducting cable shown in Figure 10. This is a cross-sectional view along the line XIII-XIII shown in Figure 10. This is a schematic diagram showing an enlarged cross-section of the superconducting tape depicted in Figure 13. This is a diagram showing a pancake coil composed of superconducting cables. This is a plan view showing an example of a coil support. This is a perspective view of the coil support shown in Figure 16A. This is a schematic diagram of the superconducting cable housed in the housing of the coil support.

[0010] The superconducting cables, coils, cable structures, and nuclear fusion reactors proposed in this disclosure will be described below. As an example of a superconducting cable, the superconducting cable 10 shown in Figures 1A to 5 will be described.

[0011] The superconducting cable 10 is used, for example, in a coil in a nuclear fusion reactor. The superconducting cable 10 is attached to a coil support (for example, the coil support 90 shown in Figures 16A and 16B) to form a coil. Once mounted on the coil support, the superconducting cable 10 is bent to match its shape. The types of nuclear fusion reactors are not particularly limited, but include, for example, helical fusion reactors and tokamak fusion reactors.

[0012] Furthermore, the superconducting cable 10 is not limited to nuclear fusion reactors, but may also be used in coils of rotary motors, linear motors, generators, magnetic resonance imaging (MRI) devices, nuclear magnetic resonance measuring devices (NMR) devices, and the like.

[0013] [Superconducting Tape] The superconducting cable 10 has a plurality of superconducting tapes 11, as shown in Figure 3A. The plurality of superconducting tapes 11 are stacked in a direction perpendicular to the extension direction of the superconducting cable 10 (Y1-Y2 in Figure 2, etc.) (the Z1-Z2 direction in Figure 3A). Hereinafter, this Z1-Z2 direction will be referred to as the "tape stacking direction". For example, several tens to several hundred superconducting tapes 11 are stacked in the tape stacking direction. The superconducting tape 11 is a wire whose thickness in the stacking direction is smaller than its width (size in the direction perpendicular to the extension direction of the cable 10). The thickness of the superconducting tape 11 may be, for example, less than 1 / 5 of its width. The thickness of the superconducting tape 11 may be less than 1 / 10 of its width. Note that the superconducting tape 11 is an example of the superconductor of the claim.

[0014] Each superconducting tape 11 is flexible. That is, the thickness and material of the superconducting tape 11 are set so that the superconducting tape 11 can be bent to conform to the shape of the coil. Also, two superconducting tapes 11 that overlap in the tape stacking direction are in contact with each other but are not fixed to each other. Therefore, these two superconducting tapes 11 are allowed to be misaligned in the direction of extension of the superconducting cable 10. This ensures flexibility in the entire bundle of multiple superconducting tapes 11 (the bundle B1 of superconducting tapes 11). (Hereafter, the bundle B1 of multiple superconducting tapes 11 will be referred to as the "tape bundle.") In addition, the multiple superconducting tapes 11 can be bent in the width direction of the superconducting cable 10 (the X1-X2 direction in Figure 1, a direction perpendicular to both the tape stacking direction and the extension direction of the superconducting cable 10) to conform to the shape of the coil.

[0015] Each superconducting tape 11, as shown in Figure 5, has a base material 11b and a superconducting layer 11d formed on the base material 11b. The material of the base material 11b is a metal, for example, a nickel alloy mainly composed of nickel. The material of the base material 11b may also contain chromium or molybdenum as additive elements.

[0016] The superconducting layer 11d is formed, for example, from a high-temperature superconducting material. The high-temperature superconducting material may contain, for example, rare earth elements such as yttrium (Y) and gadollium (Gd), as well as barium (Ba), copper (Cu), and oxygen (O). Such a superconducting material is sometimes referred to as REBCO. The material of the superconducting layer 11d is not limited to this; for example, it may be a bismuth-based oxide or a niobium alloy.

[0017] As shown in Figure 5, the superconducting tape 11 may have an intermediate layer 11c and a protective layer 11e in addition to the substrate 11b and the superconducting layer 11d. The intermediate layer 11c is a base layer formed between the substrate 11b and the superconducting layer 11d for forming the superconducting layer 11d. Examples of materials for the intermediate layer 11c include laminated films such as aluminum oxide film, yttrium oxide film, magnesium oxide film, or selenium oxide film. The protective layer 11e is provided to protect the surface of the superconducting layer 11d. The protective layer 11e is made of a material with higher electrical conductivity than the substrate 11b. Silver is an example of a material for the protective layer 11e. The superconducting tape 11 may also have a stabilizing film 11a that covers its entire surface. The stabilizing film 11a is also made of a material with high electrical conductivity. For example, copper can be used as the material for the stabilizing film 11a.

[0018] As shown in Figure 5, the multiple superconducting tapes 11 may include a superconducting tape 11_1 in which the superconducting layer 11d is located on the upper side of the substrate 11b, and a superconducting tape 11_2 in which the superconducting layer 11d is located on the lower side of the substrate 11b. These two superconducting tapes 11_1 and 11_2 may be arranged alternately. In other words, the pair of superconducting tapes 11_1 and 11_2 may be arranged so that their superconducting layers 11d face each other. This arrangement of superconducting tapes 11_1 and 11_2 reduces the electrical resistance between the connecting superconducting tape and superconducting tape 11_1, which will be described later. In this specification, when describing the two superconducting tapes 11_1 and 11_2 without distinction, the reference numeral 11 is used for the superconducting tape.

[0019] [First Reinforcement Wire] As shown in Figure 3A, the superconducting cable 10 has a plurality of first reinforcement wires 21. The first reinforcement wires 21 are, for example, tape-shaped. That is, the thickness of each first reinforcement wire 21 is sufficiently smaller than the width of the first reinforcement wire 21 (size in the X1-X2 direction). The first reinforcement wires 21 have a width greater than, for example, the superconducting tape 11. The first reinforcement wires 21 cover the outside of the tape bundle B1 and the outside of the cooling pipe 41 (upper side in Figure 3A), which will be described later.

[0020] Unlike the example shown in Figure 3A, the width of the first reinforcing wire 21 may correspond to the width of the superconducting tape 11, or it may be smaller than the width of the superconducting tape 11.

[0021] Multiple first reinforcing wires 21 are positioned on one side (the Z1 side in Figure 3) of the superconducting tape bundle B1 in the tape stacking direction. Multiple first reinforcing wires 21 are stacked in the tape stacking direction. For example, several to several dozen first reinforcing wires 21 are stacked in the tape stacking direction. Also, the first reinforcing wires 21 are in contact with the superconducting tape 11 located in the uppermost layer. When the superconducting cable 10 is bent to match the shape of a coil (see Figure 15), multiple first reinforcing wires 21 are located on the outside of the superconducting tape 11.

[0022] The first reinforcing wire 21 is positioned inside the cylindrical protective member 50 (see Figure 3A) together with the superconducting tape 11 and the cooling pipe 41. The total thickness of the multiple first reinforcing wires 21 may correspond to the distance L1 between the upper wall 51a of the protective member 50 and the superconducting tape 11. This suppresses the movement of the superconducting tape 11 inside the protective member 50 (movement in the tape stacking direction). A small gap may be provided between the upper wall 51a of the protective member 50 and the first reinforcing wire 21.

[0023] When the superconducting cable 10 is installed in a coil and current flows through the superconducting tape 11, a Lorentz force acts on the superconducting tape 11, pushing it outward from the coil (in the Z1 direction in Figure 3A). When the superconducting tape 11 is pushed outward, tensile stress (hoop stress) acts on the superconducting tape 11. Excessive stress can lead to damage to the superconducting tape 11. In the superconducting cable 10, multiple first reinforcing wires 21 are positioned between the upper wall 51a of the protective member 50 and the superconducting tape 11, reducing the gap between the upper wall 51a of the protective member 50 and the superconducting tape 11. Therefore, the spreading of the superconducting tape 11 caused by the Lorentz force (the movement of the superconducting tape 11 within the protective member 50) can be suppressed by the first reinforcing wires 21. As a result, the hoop stress acting on the superconducting tape can be reduced.

[0024] The first reinforcing wire 21 is, for example, a thin metal sheet. The material for the first reinforcing wire 21 is preferably one that has high tensile strength and high thermal conductivity. The strength of the first reinforcing wire 21 against tensile stress is preferably greater than or substantially the same as the strength of each superconducting tape 11. For example, stainless steel or beryllium copper can be used as the material for the first reinforcing wire 21.

[0025] Each first reinforcing wire 21 is formed to be flexible. For example, the thickness of each first reinforcing wire 21 is set so that each first reinforcing wire 21 is flexible. The thickness of the first reinforcing wire 21 may be, for example, 0.1 mm to 2.0 mm. The thickness of the first reinforcing wire 21 may be, for example, 0.1 mm to 1.0 mm.

[0026] Furthermore, although the two overlapping first reinforcing wires 21 in the tape lamination direction are in contact with each other, they are not fixed to each other. Therefore, the two overlapping first reinforcing wires 21 are allowed to be misaligned in the direction of extension of the superconducting cable 10. This ensures flexibility in the multiple laminated first reinforcing wires 21. In other words, the multiple first reinforcing wires 21 can be bent in the tape lamination direction to match the shape of the coil. In addition, the first reinforcing wires 21 can also be bent in a direction that intersects both the tape lamination direction and the extension direction of the superconducting cable 10 (direction X1 or X2 in Figure 1) to match the shape of the coil.

[0027] The first reinforcing wire 21 does not necessarily have to be in the shape of a tape. For example, the first reinforcing wire 21 may be a cable having a circular cross-section. In this case, multiple first reinforcing wires 21 may be arranged along the surface of the superconducting tape 11 in the uppermost layer.

[0028] As shown in Figure 3A, the superconducting cable 10 may have a plurality of second reinforcing wires 22 on the side opposite the first reinforcing wire 21, with the superconducting tape 11 in between. These second reinforcing wires 22 will be described in detail later.

[0029] [Cooling Piping] As shown in Figure 3A, the superconducting cable 10 has cooling piping 41 arranged along the tape bundle B1. The cooling piping 41 is a flow path for a refrigerant that lowers the temperature of the superconducting tape 11 to a temperature below the critical temperature. As the refrigerant, for example, liquid helium, liquid hydrogen, or liquid nitrogen may be used.

[0030] As shown in Figure 3A, the superconducting cable 10 has a plurality of cooling pipes 41. The plurality of cooling pipes 41 are arranged in the tape stacking direction. In the example shown in Figure 3A, two cooling pipes 41 are arranged in the tape stacking direction. These cooling pipes 41 are adjacent to the tape bundle B1 in the width direction (X1-X2 direction) of the superconducting cable 10. The number of cooling pipes 41 may be one or more than two. The number of cooling pipes 41 may be set according to the number of superconducting tapes 11 to be stacked, the diameter of each cooling pipe 41, and the size of the superconducting cable 10.

[0031] The cooling pipes 41 are also flexible. In other words, the wall thickness and material of the cooling pipes 41 are set so that they are flexible. Flexible bellows-type pipes (corrugated pipes) may be used as the cooling pipes 41. With this configuration, the protrusions of the bellows of one cooling pipe 41 fit into the recesses of the bellows of the other cooling pipe 41, making it more difficult for the cooling pipes 41, 41 to move in the first direction. As a result, when the superconducting cable 10 is bent, displacement of the cooling pipes 41, 41 within the protective member 50 is suppressed.

[0032] These two cooling pipes 41 may be connected via a folded portion at their ends. Alternatively, these two cooling pipes 41 may form a single pipe. In contrast, the ends of the two cooling pipes 41 may be drawn out in the width direction of the superconducting cable 10.

[0033] [Cylindrical Protective Members] As shown in Figure 1A, the superconducting cable 10 has a plurality of protective members 50 arranged in the direction of extension of the superconducting cable 10. Each protective member 50 is cylindrical. The superconducting tape 11, the reinforcing wires 21 and 22, and the cooling pipe 41 are passed inside the plurality of protective members 50. This makes it possible to prevent the superconducting tape 11, the reinforcing wires 21 and 22, and the cooling pipe 41 from separating, for example, during the coil manufacturing process.

[0034] As shown in Figure 2, each protective member 50 has a first partial protective member 51 and a second partial protective member 52. The two partial protective members 51 and 52 are combined to form a cylindrical protective member 50 having a substantially rectangular cross-section. The fact that the protective member 50 has a substantially rectangular cross-section makes it easy to arrange multiple superconducting cables 10 at high density.

[0035] As shown in Figure 3A, the first partial protective member 51 has an upper wall 51a and side walls 51b and 51c. The upper wall 51a is a wall located in the tape stacking direction relative to the first reinforcing wire 21 and the superconducting tape 11. The side walls 51b and 51c are walls located in the width direction of the superconducting cable 10 relative to the superconducting tape 11 and the cooling pipe 41. The second partial protective member 52 has a lower wall 52a and side walls 52b and 52c. The lower wall 52a is a wall located on the opposite side from the upper wall 51a, with the second reinforcing wire 22 and the superconducting tape 11 in between. The side walls 52b and 52c are located in the width direction of the superconducting cable 10 relative to the superconducting tape 11 and the cooling pipe 41. The second partial protective member 52 is fitted inside the first partial protective member 51.

[0036] The width of the first reinforcing wire 21 described above corresponds to the overall width of the cooling pipe 41 and the superconducting tape 11, and covers the outside of the cooling pipe 41 and the outside of the superconducting tape 11 (upper side in Figure 3A). Similarly, the width of the tape-shaped second reinforcing wire 22 also corresponds to the overall width of the cooling pipe 41 and the superconducting tape 11, and covers the inside of the cooling pipe 41 and the inside of the superconducting tape 11 (lower side in Figure 3A). The superconducting tape 11, the cooling pipe 41, and the reinforcing wires 21 and 22 are housed inside the protective member 50, which has a rectangular cross-section, without creating any wasted space. Inside the protective member 50, the superconducting tape 11, the cooling pipe 41, and the reinforcing wires 21 and 22 are housed with gaps large enough to allow low-melting-point metals such as U-alloy or solder to be poured in.

[0037] The partial protective members 51 and 52 are preferably formed by sheet metal processing. That is, a single metal sheet may be punched to obtain multiple intermediate parts. Then, each intermediate part may be bent to obtain multiple partial protective members 51 and 52. This reduces the cost required to manufacture the partial protective members 51 and 52. As the material for the partial protective members 51 and 52, for example, stainless steel, copper, or aluminum may be used. The manufacturing method of the partial protective members 51 and 52 is not limited to this, and they may be formed by casting, for example.

[0038] The first partial protective member 51 and the second partial protective member 52 are connected to each other so that their relative positions can change. In detail, as shown in Figure 3A, the side wall 51b of the first partial protective member 51 and the side wall 52b of the second partial protective member 52 are connected by a connecting shaft 59b. Also, the side wall 51c of the first partial protective member 51 and the side wall 52c of the second partial protective member 52 are connected by a connecting shaft 59c. The connecting shafts 59b and 59c are positioned so that their axes are aligned with the width direction of the superconducting tape 11. The relative positions of the two partial protective members 51 and 52 can change around the connecting shafts 59b and 59c. This allowance for changes in relative position allows the superconducting cable 10 to be easily bent in the tape lamination direction to conform to the shape of the coil.

[0039] In the direction of extension of the superconducting cable 10, a gap G1 (see Figure 1A) is maintained between the side walls 51b, 51c, 52b, and 52c of two adjacent protective members 50. This gap G1 increases as it moves away from the position of the connecting shafts 59b and 59c. In other words, the width of the side walls 51b and 51c in the direction of extension of the superconducting cable 10 decreases as it moves away from the position of the connecting shafts 59b and 59c. Similarly, the width of the side walls 52b and 52c in the direction of extension of the superconducting cable 10 also decreases as it moves away from the position of the connecting shafts 59b and 59c. This makes it possible to suppress interference between two adjacent protective members 50 when the superconducting cable 10 is bent in the tape lamination direction to match the shape of the coil.

[0040] The connecting shafts 59b and 59c are threaded and, as shown in Figure 3A, are fixed to the threaded holes 52g formed in the second partial protective member 52. A clearance T is ensured between the inner surface of the hole in the first partial protective member 51 and the connecting shafts 59b and 59c. This clearance T increases the degree of freedom for changing the relative position of the partial protective members 51 and 52. Unlike the example shown in Figure 3A, the connecting shafts 59b and 59c may be fixed to the first partial protective member 51. In this case, a clearance T may be ensured between the connecting shafts 59b and 59c and the hole formed in the second partial protective member 52.

[0041] As shown in Figure 3A, the ends of the connecting shafts 59b and 59c do not protrude from the side surface of the first partial protective member 51. That is, the lengths of the connecting shafts 59b and 59c are set so that they fit within the outer shape defined by the protective member 50. With this structure, when multiple superconducting cables 10 are arranged on a coil support, interference between the connecting shafts 59b and 59c and other superconducting cables 10 can be suppressed.

[0042] The structure of the protective member 50 is not limited to the example described above. For example, the connecting shafts 59b and 59c do not necessarily have to be used to connect the two partial protective members 51 and 52. For example, one of the two partial protective members 51 and 52 may have an engaging portion (e.g., a protrusion), and the other may have an engaged portion, such as a recess or hole, into which the engaging portion catches.

[0043] The partial protection members 51 and 52 may be combined with each other in a direction orthogonal to the tape lamination direction (the X1 - X2 direction shown in FIG. 3A, etc.). In this case, the first partial protection member 51 has, for example, an upper wall, a lower wall, and a right side wall (the wall on the X1 side), and these three walls may open in a direction orthogonal to both the extending direction of the superconducting cable 10 and the tape lamination direction (the X2 direction in FIG. 3A). Further, the second partial protection member 52 has, for example, an upper wall, a lower wall, and a left side wall (the wall on the X2 side), and these three walls may open in a direction orthogonal to both the extending direction of the superconducting cable 10 and the tape lamination direction (the X1 direction in FIG. 3A).

[0044] Also, in the example shown in FIG. 3A, the protection member 50 was constituted by combining two partial protection members 51 and 52. However, the protection member 50 may be a single cylindrical member. Such a protection member 50 may also be formed by sheet metal working.

[0045] Also, in the example shown in FIG. 1A, etc., there is substantially no gap between the upper walls 51a of two adjacent protection members 50. However, a gap may also be secured between these two upper walls 51a. For example, a plurality of protection members 50 may be arranged at regular intervals in the extending direction of the superconducting cable 10.

[0046] [Second Reinforcing Wire] As shown in FIG. 3A, the superconducting cable 10 has a plurality of second reinforcing wires 22. The plurality of second reinforcing wires 22 are arranged on the opposite side (the Z2 side in FIG. 3A) of the first reinforcing wire 21 with the superconducting tape 11 interposed therebetween. The second reinforcing wire 22 may be in contact with the superconducting tape 11 located in the lowermost layer. When the superconducting cable 10 is bent in accordance with the shape of the coil, the second reinforcing wire 22 is located inside the superconducting tape 11.

[0047] The second reinforcing wire 22 may be in a tape shape, similar to the first reinforcing wire 21. That is, the thickness of each second reinforcing wire 22 is sufficiently smaller than the width of the second reinforcing wire 22 (size in the X1 - X2 direction). In the example shown in Fig. 3A, the number of the second reinforcing wires 22 is less than the number of the first reinforcing wires 21. The number of the first reinforcing wires 21 and the number of the second reinforcing wires 22 may be the same, that is, the thicknesses of the stacked first reinforcing wires 21 and the stacked second reinforcing wires 22 may be the same. Also, in an example, the thicknesses of the reinforcing wires 21 and 22 may be similar. Thereby, the number of types of components of the superconducting cable 10 can be reduced, and the manufacturing process of the superconducting cable 10 can be simplified. Note that the thicknesses of the reinforcing wires 21 and 22 may be different. For example, the thickness of the first reinforcing wire 21 may be larger than the thickness of the second reinforcing wire 22. By doing so, the strength of the superconducting cable 10 can be further increased by the first reinforcing wire 21.

[0048] The second reinforcing wire 22 is, for example, a thin metal plate. As the material of the second reinforcing wire 22, similar to the first reinforcing wire 21, stainless steel, beryllium copper, etc. can be used. The second reinforcing wire 22 is formed to have flexibility. For example, the thickness is set so that the second reinforcing wire 22 has flexibility. The thickness of the second reinforcing wire 22 may be, for example, 0.1 millimeter to 2.0 millimeters. The thickness of the second reinforcing wire 22 may be, for example, 0.1 millimeter to 1.0 millimeter.

[0049] [Pressing Structure] The superconducting cable 10 may have a pressing structure that presses a plurality of superconducting tapes 11 against the first reinforcing wire 21. As shown in Fig. 3B, the superconducting cable 10 has a pressing screw 56 and a support plate 57 as a pressing structure. The superconducting cable 10 has a plurality of support plates 57 arranged side by side in its stretching direction. Each support plate 57 is disposed between the lower wall 52a of the protection member 50 and the second reinforcing wire 22.

[0050] As shown in Figure 3B, a screw hole is formed in the support plate 57. A pressure screw 56 is inserted into this screw hole. A hole 52h is formed in the lower wall 52a of the second portion protective member 52 to expose the screw hole of the support plate 57. The pressure screw 56 pushes the second reinforcing wire 22 toward the superconducting tape 11. As a result, the superconducting tape 11 is pressed against the first reinforcing wire 21, eliminating the gap between the multiple superconducting tapes 11 and the multiple first reinforcing wires 21. As a result, for example, when a Lorentz force acts on the superconducting tape 11, it is possible to suppress changes in the position of the superconducting tape 11 in the tape stacking direction. In addition, since the second reinforcing wire 22 is positioned between the pressure screw 56 and the superconducting tape 11, the force acting from the pressure screw 56 on the superconducting tape 11 can be distributed. Furthermore, this pressure structure can suppress changes in the position of the protective member 50 in the extension direction of the superconducting cable 10.

[0051] As shown in Figure 1B, each protective member 50 may be provided with, for example, multiple pressure screws 56 (four pressure screws 56 in Figure 1B). Some of the pressure screws 56 may be located on the inside of the superconducting tape 11 (the lower side in Figure 3B). The remaining pressure screws 56 may be located on the inside of the cooling pipe 41 (the lower side in Figure 3B).

[0052] In the initial state, that is, before the superconducting cable 10 is bent to match the shape of the coil, the pressure screw 56 does not need to be tightened. This allows the relative positions of the multiple superconducting tapes 11 and the multiple first reinforcing wires 21 in the stretching direction of the superconducting cable 10 to change easily. As a result, the superconducting cable 10 can be easily bent. After the superconducting cable 10 has been bent to match the shape of the coil, the pressure screw 56 may be tightened.

[0053] As shown in Figure 3B, the end of the pressure screw 56 does not protrude from the lower surface of the second protective member 52. That is, the length of the pressure screw 56 is set so that the entire pressure screw 56 fits within the outer shape defined by the protective member 50. With this structure, when multiple superconducting cables 10 are arranged on the coil support, interference between the pressure screw 56 and other superconducting cables 10 can be suppressed.

[0054] The superconducting cable 10 does not necessarily have a support plate 57 as a pressurized structure. In this case, a screw hole for inserting a pressurized screw 56 may be formed in the lower wall 52a of the second portion protective member 52.

[0055] Furthermore, the pressurizing structure is not limited to the pressurizing screw 56 and the support plate 57. For example, a protrusion (e.g., a leaf spring portion) that presses the second reinforcing wire 22 may be formed on the protective member 50.

[0056] Furthermore, the superconducting cable 10 does not necessarily have a pressurized structure including a pressurized screw 56 and a support plate 57. In this case, the superconducting cable 10 does not necessarily have a second reinforcing wire 22.

[0057] [Fixing Members] As shown in Figure 1A, the superconducting cable 10 has two fixing members 30A and 30B that are located apart in the direction of extension of the superconducting cable 10. Each fixing member 30A and 30B holds a portion of the first reinforcing wire 21 in the direction of extension of the superconducting cable 10. Specifically, as shown in Figure 2, the multiple first reinforcing wires 21 have a held portion 21a at their ends. The held portion 21a is the portion that extends beyond the end of the superconducting tape 11 and the protective member 50. The first fixing member 30A holds this held portion 21a. The multiple first reinforcing wires 21 also have a held portion 21a at the opposite end. The second fixing member 30B holds this held portion 21a.

[0058] In the following explanation, if these two fixing members 30A and 30B are not distinguished, the reference numeral 30 will be used for both fixing members 30A and 30B.

[0059] When the superconducting cable 10 is mounted on the coil, these two fixing members 30A and 30B may be fixed to the coil support (for example, the coil support 90 shown in Figure 16A). The fixing members 30A and 30B may be welded to the coil support, for example. The fixing members 30A and 30B may be fixed to the coil support by fasteners such as screws or bolts. When the fixing members 30A and 30B are fixed to the coil support, the change in the distance between the two fixing members 30A and 30B is restricted, and the elongation of the superconducting cable 10 is limited. As a result, even when a Lorentz force acts on the superconducting tape 11, the hoop stress acting on the superconducting tape 11 can be reduced.

[0060] Furthermore, the fixing member 30 does not necessarily have to be directly fixed to the coil support. That is, the fixing member 30 may be indirectly fixed to the coil support via other components (for example, the fixing member 30 of another superconducting cable 10).

[0061] Each fixing member 30 holds a second reinforcing wire 22 in addition to the first reinforcing wire 21. As shown in Figure 2, each of the multiple second reinforcing wires 22 also has a held portion 22a at both ends. The held portion 22a is the portion that extends beyond the end of the superconducting tape 11 and the protective member 50. Each fixing member 30A and 30B holds this held portion 22a.

[0062] As described above, the protective member 50 is provided with a pressurizing structure (pressurizing screw 56 and support plate 57) for pushing the superconducting tape 11 toward the first reinforcing wire 21. This pressurizing structure can reduce the gaps between members arranged inside the protective member 50. For example, it can reduce the gaps between multiple superconducting tapes 11 and the gaps between multiple first reinforcing wires 21. As a result, the movement of the superconducting tape 11 caused by the Lorentz force acting on it can be reduced.

[0063] It should be noted that such a pressurizing structure is not necessarily provided on all protective members 50. In other words, the pressurizing structure may be provided only on some of the protective members 50 that are separated in the stretching direction.

[0064] [Details of Fixing Members] Each fixing member 30 may have, for example, a main body 31, a cover 32, a pressing member 33, and a connecting pin 34, as shown in Figure 2. These are made of metal. For example, these materials may be stainless steel or beryllium copper.

[0065] As shown in Figure 4, the main body 31 has a first groove 31a, a second groove 31b, and a third groove 31c. The first groove 31a extends in the direction of extension of the superconducting cable 10. The second groove 31b extends from the first groove 31a to one side in the tape stacking direction (upward in Figure 4). The third groove 31c extends from the first groove 31a to the other side in the tape stacking direction (downward in Figure 4). That is, the second groove 31b and the third groove 31c extend in different directions from the first groove 31a. For example, both a plurality of first reinforcing lines 21 and a plurality of second reinforcing lines 22 are arranged in the first groove 31a. A plurality of first reinforcing lines 21 and a portion of the plurality of second reinforcing lines 22 are arranged in the second groove 31b, and the remainder of the plurality of first reinforcing lines 21 and a plurality of second reinforcing lines 22 are arranged in the third groove 31c.

[0066] The cover 32 is attached to the side of the main body 31 and closes the grooves 31a, 31b, and 31c. The cover 32 may be fixed to the main body 31 with screws, for example.

[0067] The fixing member 30 and the reinforcing wires 21 and 22 are fixed to each other in such a way that changes in their relative positions in the extension direction of the superconducting cable 10 are restricted. Specifically, as shown in Figure 4, holes 31d, 21c, and 22c are formed in the main body 31, the first reinforcing wire 21, and the second reinforcing wire 22, passing through them in the tape lamination direction. Connecting pins (connectors) 34 are inserted into these through holes 31d, 21c, and 22c. This restricts changes in the relative positions of the held portions 21a and 22a of the reinforcing wires 21 and 22 and the superconducting tape 11 in the extension direction of the superconducting cable 10.

[0068] In the example shown in Figure 4, one connecting pin 34 is used to fix the fixing member 30 to the held parts 21a and 22a. However, there may be two or more connecting pins 34. In this case, the force acting between each connecting pin 34 and the reinforcing wires 21 and 22 when hoop stress acts on the superconducting tape 11 can be reduced. As yet another example, screws or bolts may be used to fix each fixing member 30 to the held parts 21a and 22a. Also, the held parts 21a and 22a may be welded to the fixing member 30.

[0069] As shown in Figure 4, the pressing member (intervening member) 33 is positioned in the second groove 31b and the third groove 31c of the main body 31 together with the held portions 21a and 22a of the reinforcing wires 21 and 22. The pressing member 33 is pressed against the held portions 21a and 22a of the reinforcing wires 21 and 22 by fixing screws 35 (see Figure 1A) fitted from the outside of the main body 31. This fixes the relative position between the held portions 21a and 22a and the main body 31.

[0070] The pressing member 33 may be used in the process of attaching the fixing member 30 to the reinforcing wires 21 and 22. For example, after fitting the held portions 21a and 22a of the reinforcing wires 21 and 22 into the grooves 31a, 31b, and 31c of the main body 31, the held portions 21a and 22a are fixed to the main body 31 by the pressing member 33 and fixing screws 35. After that, the superconducting cable 10 is curved to follow the coil. As a result, the positions of the multiple first reinforcing wires 21 and the multiple second reinforcing wires 22 change in accordance with the curve. After that, if the tips of the reinforcing wires 21 and 22 protrude above or below the grooves 31b and 31c, the protruding portions are cut off. At this time, through holes 21c and 22c (see Figure 4) may be formed in the first reinforcing wire 21 and the second reinforcing wire 22. These through holes 21c and 22c are formed at positions corresponding to the through hole 31d of the main body 31. Finally, the connecting pins 34 are inserted into the through holes 31d, 21c, and 22c. This ensures that the through holes 21c and 22c are formed in positions suitable for the curvature of the superconducting cable 10.

[0071] Furthermore, after the connecting pins 34 are inserted into the through holes 31d, 21c, and 22c and the fixing member 30 and the reinforcing wires 21 and 22 are positioned relative to each other, the pressing member 33 may be removed. Alternatively, as another example of the assembly process, the through holes 21c and 22c may be formed in the reinforcing wires 21 and 22 first, then the holding portions 21a and 22a of the reinforcing wires 21 and 22 may be fitted into the grooves 31c, 31b, and 31c of the fixing member 30, and finally the connecting pins 34 may be inserted into the through holes 31d, 21c, and 22c. In this case, the pressing member 33 may not necessarily be used.

[0072] As shown in Figure 1A, the size W1 of the fixing member 30 in the width direction of the superconducting cable 10 and the size W2 of the protective member 50 in the same direction may be substantially the same. For example, the size W1 of the fixing member 30 may be less than 1.2 times the size W2 of the protective member 50. Similarly, the size W3 of the fixing member 30 in the tape lamination direction and the size W4 of the protective member 50 in the same direction may be substantially the same. For example, the size W3 of the fixing member 30 may be less than 1.2 times the size W4 of the protective member 50. This makes it possible to suppress interference between the fixing members 30A and 30B and surrounding members, making it easier to construct a coil with multiple superconducting cables 10.

[0073] Furthermore, a fixing member for holding the first reinforcing wire 21 may be provided not at the end of the superconducting cable 10, but in the middle of the superconducting cable 10. This fixing member may be located between two adjacent protective members 50 in the extending direction of the superconducting cable 10. This fixing member may be fixed to the first reinforcing wire 21 by fasteners such as screws, pins, or bolts so as to restrict changes in the relative position between the fixing member and the first reinforcing wire 21. This fixing member may then be fixed directly or indirectly to the coil support. In this case, the fixing member 30 described above may also be provided at the end of the superconducting cable 10.

[0074] [Cable Structure for Drawing Superconducting Tape] This section describes a cable structure for drawing superconducting tape in the width direction from a superconducting cable. Figures 6 to 9 show examples of cable structures. Figure 6 is a perspective view of cable structure 100, and Figure 7 is an exploded perspective view of cable structure 100. Figure 8 is a cross-sectional view taken along the line VIII-VIII shown in Figure 6. Figure 9 is a schematic diagram showing an enlarged view of the cross-section of the superconducting tape depicted in Figure 8.

[0075] In the following, the same reference numerals are used for the parts, components, and elements described with reference to Figures 1A to 5. In the structures shown in Figures 6 to 9, items not described may be the same as those described in Figures 1A to 5.

[0076] As shown in Figure 6, the cable structure 100 includes a superconducting cable 10A and a superconducting tape 11A (see Figure 8) connected to the superconducting cable 10A. Hereinafter, this will be referred to as the connecting superconducting tape 11A. The connecting superconducting tape 11A is connected to external devices such as an external power supply or a coil protection circuit. The connecting superconducting tape 11A extends in a direction intersecting the extension direction of the superconducting cable 10A and the tape stacking direction (the width direction of the superconducting tape 11). Multiple connecting superconducting tapes 11A are stacked in the tape stacking direction to form one tape bundle B2. The cable structure 100 has multiple tape bundles B2 (three tape bundles B2) arranged in the extension direction of the superconducting cable 10A. In this way, multiple tape bundles B2 are connected to the superconducting cable 10A, so that the electrical resistance between the superconducting cable 10 and external devices such as an external power supply can be reduced. The connecting superconducting tape 11A is a wire whose thickness in the lamination direction is smaller than its width (size in the direction perpendicular to the extension direction of the cable 10). The thickness of the connecting superconducting tape 11A may be, for example, less than 1 / 5 of its width. The thickness of the connecting superconducting tape 11A may also be less than 1 / 10 of its width. Note that the connecting superconducting tape 11A is an example of the connecting superconductor described in the claim.

[0077] In the superconducting cable 10A, the portion where the superconducting tape 11 and the connecting superconducting tape 11A are connected will be referred to below as the connection region C (see Figure 6). In the connection region C, one or more connecting superconducting tapes 11A are inserted between two superconducting tapes 11 that overlap in the tape stacking direction. For example, as shown in Figure 9, the superconducting tapes 11 and the connecting superconducting tapes 11A are arranged alternately in the tape stacking direction.

[0078] In the superconducting cable 10A, similar to the structure shown in Figure 5, the multiple superconducting tapes 11 have superconducting tapes 11_1 in which the superconducting layer 11d is located on the upper side of the base material 11b, and superconducting tapes 11_2 in which the superconducting layer 11d is located on the lower side of the base material 11b. These two superconducting tapes 11_1 and 11_2 are arranged alternately. In the connection region C shown in Figure 6, one of the two superconducting tapes 11_1 and 11_2 is cut. For example, as shown in Figure 9, in the connection region C, superconducting tape 11_2 is cut, and only superconducting tape 11_1 remains. Then, a connecting superconducting tape 11A is inserted between the two superconducting tapes 11_1. In the connecting superconducting tape 11A, similar to the cut superconducting tape 11_2, the superconducting layer 11d is located on the lower side of the base material 11b.

[0079] According to this connection method, the superconducting tape 11 and the connecting superconducting tape 11A form a pair in which there is no substrate 11b between their superconducting layers 11d, 11d. For example, in Figure 9, there is no substrate 11b between the superconducting layer 11d of the superconducting tape 11_1 drawn at the bottom and the superconducting layer 11d of the connecting superconducting tape 11A drawn above it. Therefore, the electrical resistance between these two superconducting layers 11d can be reduced. In this connection method, it is preferable that the superconducting tape 11_1 and the superconducting tape 11_2 are acid-treated beforehand. By removing the oxide layer formed on the stabilizing film 11a through acid treatment, the electrical resistance between these two superconducting layers 11d can be further reduced.

[0080] As shown in Figure 6, the superconducting cable 10A has protective members 50A in the connection region C. In the example shown in Figure 6, three protective members 50A are arranged in the direction of extension of the superconducting cable 10A. As shown in Figure 7, the connection portion between the superconducting tape 11 and the connecting superconducting tape 11A, the cooling pipe 41, and the reinforcing wires 21 and 22 are arranged inside the protective members 50A.

[0081] An opening 50e (see Figure 6) is formed on the side of the protective member 50A. The connecting superconducting tape 11A is inserted into this opening 50e. As shown in Figure 7, the protective member 50A has a first partial protective member 53 and a second partial protective member 54. The two partial protective members 53 and 54 constitute a cylindrical protective member 50A having a substantially rectangular cross-section.

[0082] As shown in Figure 8, the first partial protective member 53 has an upper wall 53a and side walls 53b and 53c. The upper wall 53a is a wall located in the tape stacking direction with respect to the first reinforcing wire 21 and the superconducting tape 11. An opening 53e is formed in the side wall 53b. The second partial protective member 54 has a lower wall 54a and side walls 54b and 54c. The lower wall 54a is a wall located on the opposite side from the upper wall 53a, with the reinforcing wires 21 and 22 and the superconducting tape 11 in between. An opening 54e (see Figure 7) is formed in the lower wall 54a and the side walls 54b and 54c. The openings 53e and 54e are combined to form an opening 50e of the protective member 50A that opens in the width direction of the superconducting cable 10A.

[0083] Note that the structure of the partial protective members 53 and 54 is not limited to the example described here. For example, as in the example described with reference to Figure 1A, the partial protective members 53 and 54 may be combined with each other in a direction perpendicular to the tape stacking direction (the X1-X2 direction shown in Figure 6, etc.). In this case, the first partial protective member 53 has, for example, an upper wall, a lower wall, and a right side wall (the wall on the X1 side), and these three walls may open in a direction perpendicular to both the extension direction of the superconducting cable 10A and the tape stacking direction (the X2 direction). The second partial protective member 54 has, for example, an upper wall, a lower wall, and a left side wall (the wall on the X2 side), and these three walls may open in a direction perpendicular to both the extension direction of the superconducting cable 10A and the tape stacking direction (the X1 direction). In this case, the upper wall of the first partial protective member 53 and the upper wall of the second partial protective member 54 may be connected, and the lower wall of the first partial protective member 53 and the lower wall of the second partial protective member 54 may be connected. In addition, openings may be formed in the side walls of the partial protective members 53 and 54 for passing the connecting superconducting tape 11A through.

[0084] The protective member 50A is also provided with the aforementioned pressurizing structure. Specifically, as shown in Figure 8, a pressurizing screw 56 and a support plate 57 are provided on the protective member 50A. This pressurizing structure ensures tight adhesion between the superconducting tape 11 and the connecting superconducting tape 11A.

[0085] The protective member 50A may be provided with a pressure screw 56 located on the underside of the superconducting tape 11 (one side in the tape stacking direction) and a pressure screw 56 located on the underside of the cooling pipe 41. In this case, the pressure screw 56 located on the underside of the superconducting tape 11 may apply a higher pressure to the second reinforcing wire 22 than the pressure screw 56 located on the underside of the cooling pipe 41. This can increase the adhesion between the superconducting tape 11 and the connecting superconducting tape 11A.

[0086] The superconducting cable 10A does not necessarily have a support plate 57 as a pressurized structure. In this case, a screw hole for inserting a pressurized screw 56 may be formed in the lower wall 54a of the second partial protective member 54.

[0087] As shown in Figure 6, the superconducting cable 10A also has a fixing member 30. The connection region C is provided at the end of the superconducting tape 11. The fixing member 30 is provided in the portion of the superconducting tape 11 that extends beyond the end in the direction of extension of the superconducting tape 11. The connection region C and the fixing member 30 are in close proximity, and no other protective member is placed between the protective member 50A that constitutes the connection region C and the fixing member 30.

[0088] As shown in Figure 6, a cooling pipe 41 may be drawn out from the end of the superconducting cable 10A. The superconducting cable 10A has two cooling pipes 41, similar to the superconducting cable 10 shown in Figure 1, etc. In the cable structure 100, the two cooling pipes 41 pass between the protective member 50A and the fixing member 30 located at the end and extend in the width direction (X1 direction) of the superconducting cable 10A. In this case, a refrigerant may be supplied to one of the two cooling pipes 41, and the refrigerant may be discharged from the other cooling pipe 41.

[0089] [Cable structure for connecting two superconducting cables] Figures 10 to 14 are diagrams illustrating a cable structure for connecting two superconducting cables. Figure 10 is a perspective view of the cable structure 200. Figure 11 is an exploded view of the cable structure shown in Figure 10. Figure 12 is an exploded perspective view of the superconducting cable shown in Figure 10. Figure 13 is a cross-sectional view taken along the line XIII-XIII shown in Figure 10. Figure 14 is a schematic diagram showing an enlarged view of the cross-section of the superconducting tape depicted in Figure 13.

[0090] In the following, the same reference numerals are used for the parts, components, and elements described with reference to Figures 1 to 9. In the cable structures shown in Figures 10 to 14, items not described may be the same as those described in Figures 1 to 9.

[0091] The cable structure 200 has two superconducting cables 10B and 10C and a connecting superconducting tape 11B (see Figures 13 and 14) that connects them. The superconducting cables 10B and 10C are adjacent to each other in their width direction (X1-X2 direction). The superconducting cables 10B and 10C have a superconducting tape 11, a protective member 50, reinforcing wires 21 and 22, and a fixing member 30, similar to the superconducting cable 10 exemplified in Figure 1A, etc. Furthermore, the superconducting cables 10B and 10C have a connection region C at the end of the superconducting tape 11. The superconducting tapes 11 of the superconducting cables 10B and 10C are connected via the connecting superconducting tape 11B in the connection region C.

[0092] As shown in Figure 11, the cable structure 200 has multiple tape bundles B3 (three tape bundles B3), each composed of multiple connecting superconducting tapes 11B. Since the two superconducting cables 10B and 10C are connected to each other via multiple tape bundles B3 in this way, the electrical resistance between the two superconducting cables 10B and 10C can be reduced. The superconducting cables 10B and 10C have protective members 50A in the connection region C. In the connection region C, three protective members 50A are arranged in the direction of extension of the superconducting cables 10B and 10C. The number of protective members 50A constituting the connection region C may be less than three or more than three.

[0093] As shown in Figure 11, an opening 50e is formed on the side of the protective member 50A. The superconducting cables 10B and 10C are arranged such that this opening 50e faces the superconducting cables 10B and 10C in the width direction (X1-X2 direction). The tape bundle B3 is connected to the superconducting tape 11 of the superconducting cables 10B and 10C through this opening 50e.

[0094] As shown in Figure 13, the superconducting cables 10B and 10C have cooling pipes 41. The superconducting tapes 11 are positioned between the cooling pipes 41 of each superconducting cable 10B and 10C.

[0095] In the connection region C, one or more connecting superconducting tapes 11B are inserted between two superconducting tapes 11 that are aligned in the tape stacking direction. For example, as shown in Figure 14, the superconducting tapes 11 and the connecting superconducting tapes 11B are arranged alternately in the tape stacking direction.

[0096] Similar to the structure shown in Figure 5, in the superconducting cables 10B and 10C, the multiple superconducting tapes 11 include superconducting tape 11_1 in which the superconducting layer 11d is located on the upper side of the base material 11b, and superconducting tape 11_2 in which the superconducting layer 11d is located on the lower side of the base material 11b. These two superconducting tapes 11_1 and 11_2 are arranged alternately. In the connection region C of the superconducting cables 10B and 10C, one of the two superconducting tapes 11_1 and 11_2 is cut. For example, as shown in Figure 14, in the connection region C, superconducting tape 11_2 is cut, and only superconducting tape 11_1 remains. A connecting superconducting tape 11B is then inserted between the two superconducting tapes 11_1 which are arranged in the tape stacking direction. In each connecting superconducting tape 11B, the superconducting layer 11d is located on the lower side of the base material 11b, similar to the cut superconducting tape 11_2.

[0097] According to this connection method, the superconducting tape 11 and the connecting superconducting tape 11B form a pair in which there is no substrate 11b between their superconducting layers 11d. For example, as shown in Figure 14, in both the superconducting cables 10B and 10C, there is no substrate 11b between the superconducting layer 11d of the superconducting tape 11_1 drawn at the bottom and the superconducting layer 11d of the connecting superconducting tape 11A drawn above it. Therefore, the electrical resistance between these two superconducting layers 11d can be reduced.

[0098] The protective member 50A is also provided with the aforementioned pressurizing structure. Specifically, as shown in Figure 13, a pressurizing screw 56 and a support plate 57 are provided on the protective member 50A. This pressurizing structure increases the adhesion between the superconducting tape 11 and the connecting superconducting tape 11B.

[0099] Furthermore, the superconducting cables 10B and 10C do not necessarily have a support plate 57 as a pressurized structure. In this case, a screw hole for inserting a pressurized screw 56 may be formed in the lower wall 54a of the second portion protective member 54.

[0100] As shown in Figure 10, the superconducting cables 10B and 10C also have fixing members 30. The fixing members 30 are provided on the portion of the superconducting tape 11 that extends beyond the end in the direction of extension of the superconducting cables 10B and 10C. A connection region C is provided between the fixing member 30 of the superconducting cable 10B and the fixing member 30A of the superconducting cable 10C. Each fixing member 30 and the connection region C are in close proximity. That is, no other protective member is placed between the protective member 50A that constitutes the connection region C and the fixing member 30. This makes it possible to suppress misalignment between the connection region C of the superconducting cable 10B and the connection region C of the superconducting cable 10C.

[0101] In the example shown in Figure 10, etc., the superconducting cable 10B extends from the fixing member 30 in the Y2 direction, while the superconducting cable 10C extends from the fixing member 30 in the Y1 direction. That is, the superconducting cables 10B and 10C extend from the fixing member 30 in opposite directions. However, the extension directions of these two superconducting cables 10B and 10C are not limited to this. For example, the two superconducting cables 10B and 10C may extend from the fixing member 30 in the same direction. For example, both of the two superconducting cables 10B and 10C may extend from their respective fixing members 30 in the Y1 direction. In this case as well, the two superconducting cables 10B and 10C may be arranged so that the openings 50e of their protective members 50A face each other, and the superconducting tapes 11 of the superconducting cables 10B and 10C may be electrically connected to each other via the superconducting tape 11B.

[0102] In Figure 11, multiple protective members 50A (three protective members 50A in Figure 11) with openings 50e are arranged in a continuous sequence. However, the multiple protective members 50A, 50A, 50A with openings 50e do not necessarily have to be arranged in a continuous sequence. That is, a protective member 50 without an opening 50e, as shown in Figure 1A, may be placed between two adjacent protective members 50A. Also, in Figure 11, the openings 50e are provided in the three protective members 50A closest to the fixing member 30 in both the superconducting cables 10B and 10C. However, for example, protective members 50A with openings 50e may be placed in the 2nd, 4th, and 6th positions from the protective member closest to the fixing member 30, while protective members 50 without openings 50e may be placed in the 1st, 3rd, and 5th positions. In this way, the position of the openings 50e can be adjusted, increasing the degree of freedom in the electrical connection of the cables 10B and 10C.

[0103] As yet another example, a single protective member may have multiple openings 50e aligned in the direction of extension of the superconducting cable 10. This reduces the number of parts.

[0104] [Pancake Coil] Figure 15 shows a pancake coil 300 having the cable structure 100 illustrated in Figure 6, etc. and the cable structure 200 illustrated in Figure 10, etc.

[0105] The pancake coil 300 has two superconducting cables 10E and 10F. The first superconducting cable 10E is wound around the center line C1 of the coil 300. The second superconducting cable 10F is wound around the center line C1 of the coil 300. The first superconducting cable 10E and the second superconducting cable 10F constitute the first and second layers, respectively, which are superimposed in the direction of the center line C1. Each superconducting cable 10E and 10F is wound such that the first reinforcing wire 21 (see Figure 3A) is located on the outside of the coil 300 relative to the superconducting tape 11.

[0106] Furthermore, these two superconducting cables 10E and 10F have a cable structure 100 at their ends, as illustrated in Figure 6, etc. Specifically, a connecting superconducting tape 11A is connected to the ends of the superconducting cables 10E and 10F. Cooling pipes 41 are also drawn out from the ends of each superconducting cable 10E and 10F. In the example shown in Figure 15, the cable structure 100 is located in the center of the coil 300.

[0107] Furthermore, these two superconducting cables 10E and 10F have a cable structure 200 at the end opposite to the cable structure 100, as illustrated in Figure 10, etc. In the example shown in Figure 15, the cable structure 200 is provided on the outer circumference of the coil 300. That is, these two superconducting cables 10E and 10F are connected at the outer circumference of the coil 300 via a connecting superconducting tape 11B (see Figure 11).

[0108] The coil 300 is placed on a coil support (not shown). The fixing members 30, which are provided at the ends of the superconducting cables 10E and 10F, are fixed to this coil support. The superconducting cables 10E and 10F placed on the coil support can be fixed to each other and to the coil support by pouring a low-melting-point metal such as U-alloy or solder into the gaps between the superconducting cables 10E and 10F.

[0109] [Coils in a Fusion Reactor] Figures 16A and 16B show examples of coil supports. The coil support 90 shown in these figures constitutes a helical-type fusion reactor. The coil support 90, together with a bracket that confines the plasma, is housed in a vacuum vessel.

[0110] As shown in Figure 16A, the coil support 90 is double-helix in shape. That is, the coil support 90 has two coil housings 91A and 91B formed along a torus plane centered on the vertical center line C2. Multiple hollow tubes 91a to 91d (see Figure 16B) are formed in each of the coil housings 91A and 91B. Multiple superconducting cables 10, 10A, 10B, and 10C described above are arranged in each of these hollow tubes 91a to 91d.

[0111] Figure 17 is a schematic diagram showing an example of a superconducting cable 10 arranged in a housing 91A. As shown in the figure, multiple superconducting cables 10 are arranged in hollow tubes 91a and 91b formed in the housing 91A. The inside of these hollow tubes 91a and 91b may be filled with a low-melting-point metal. In this way, an uninsulated coil is realized in which multiple superconducting cables 10 are short-circuited with the low-melting-point metal. As the low-melting-point metal, for example, a U-alloy 78 with a melting point of about 78 degrees can be used.

[0112] As shown in Figure 16B, the coil support 90 may have coil housings 92A, 92B, 93A, and 93B for forming an annular vertical magnetic field coil centered on the vertical centerline C2. The coil housings 92A and 92B are formed inside the torus. The housings 93A and 93B are formed outside the torus. A superconducting cable 10 or the like is also housed in the hollow tube formed inside these coil housings.

[0113] [Summary] (1) As described above, the superconducting cable 10 has a plurality of flexible superconducting tapes 11 that are stacked in a tape stacking direction perpendicular to the extension direction of the superconducting cable 10, at least one flexible first reinforcing wire 21 that extends in the extension direction of the superconducting cable 10, is superimposed on the plurality of superconducting tapes 11 in the tape stacking direction, a first fixing member 30A that holds a first held portion 21a which is a part of the first reinforcing wire 21 in the extension direction of the superconducting cable 10, and a second fixing member 30B that holds a second held portion 21a which is another part of the first reinforcing wire 21 in the extension direction of the superconducting cable 10. With this superconducting cable 10, the extension of the superconducting cable 10 between them can be suppressed by fixing the positions of the two fixing members 30A and 30B. As a result, even when a Lorentz force acts on the superconducting tape 11, the hoop stress acting on the superconducting tape 11 can be reduced.

[0114] (2) In the superconducting cable of (1), the first retained portion 21a of the first reinforcing wire 21 is the portion that extends beyond the ends of the plurality of superconducting tapes 11 toward one side in the extension direction of the superconducting cable 10.

[0115] (3) In the superconducting cable of (2), the second retained portion 21a of the first reinforcing wire 21 is the portion that extends beyond the ends of the plurality of superconducting tapes 11 toward the opposite side of the extension direction of the superconducting cable 10.

[0116] (4) The superconducting cable 10 described in any of (1) to (3) includes a plurality of first reinforcing wires 21 which are stacked in the tape stacking direction and which allow for relative misalignment in the stretching direction of the superconducting cable 10. This structure makes it possible to more effectively suppress the elongation of the superconducting cable 10. In addition, it is possible to ensure the flexibility of the superconducting cable 10.

[0117] (5) The superconducting cable 10 described in any of (1) to (4) further includes a second reinforcing wire 22 which is positioned on the opposite side of the first reinforcing wire 21, with a plurality of superconducting tapes 11 in between.

[0118] (6) The superconducting cable 10 described in any of (1) to (5) has a cylindrical protective member 50. The multiple superconducting tapes 11 and the first reinforcing wire 21 are arranged inside the protective member 50. This makes it possible to suppress the separation of the multiple superconducting tapes 11 and the reinforcing wire 21.

[0119] The superconducting cable 10 described in (7) and (6) includes a plurality of protective members 50 arranged in the direction of extension of the superconducting cable 10. This allows the flexibility of the superconducting cable 10 to be maintained.

[0120] (8) The coil proposed in this disclosure comprises a coil support 90 and a plurality of superconducting cables 10 arranged along the coil support 90. A first fixing member 30A and a second fixing member 30B are fixed directly or indirectly to the coil support 90. This makes it possible to suppress changes in the distance between the fixing members 30A and 30B when current is passed through the superconducting tape 11.

[0121] (9) The cable structure 200 proposed in this disclosure (see Figure 10) has two superconducting cables 10B and 10C. Each superconducting cable 10B and 10C has a connection region C. The connection region C of one superconducting cable 10B and the connection region C of the other superconducting cable 10C are aligned in the width direction of the superconducting tape 11 and are connected to each other via the connecting superconducting tape 11B. With this, the superconducting cables 10B and 10C can be connected without causing interference between the fixing member 30 of the superconducting cable 10B and the fixing member 30 of the superconducting cable 10C.

[0122] (10) As described above, the superconducting cable 10 comprises a plurality of flexible superconducting tapes 11 that are stacked in the tape stacking direction, a first reinforcing wire 21 that extends in the extension direction of the superconducting cable 10 and is superimposed on the plurality of superconducting tapes 11 in the tape stacking direction and is flexible, and a plurality of protective members 50 that are each formed in a cylindrical shape and surround the plurality of superconducting tapes 11 and the first reinforcing wire 21 and are aligned in the extension direction of the superconducting cable 10. With this superconducting cable 10, the movement of the superconducting tapes 11 inside the protective members 50 (movement caused by the Lorentz force) can be suppressed by the first reinforcing wire 21. As a result, the hoop stress acting on the superconducting tapes 11 can be reduced.

[0123] In the superconducting cable of (11) and (10), each of the multiple protective members 50 has a first partial protective member 51 and a second partial protective member 52 that are combined with each other to form a cylindrical shape. The first partial protective member 51 and the second partial protective member 52 are connected to each other so that their relative positions change in accordance with the curvature of the superconducting cable 10. This makes it possible to easily bend the superconducting cable 10 to match the shape of the coil.

[0124] In the superconducting cable of (12) and (11), the first partial protective member 51 and the second partial protective member 52 are formed of sheet metal. This makes it easier to manufacture the protective member 50.

[0125] The superconducting cable 10 described in any of (13), (10), to (12) is arranged inside a plurality of protective members 50 and has a cooling pipe 41 that extends along a plurality of superconducting tapes 11. This structure makes it possible to suppress the separation of the plurality of superconducting tapes 11, the reinforcing wire 21, and the cooling pipe 41.

[0126] The superconducting cable 10 described in any of (14), (10), to (13) has a first reinforcing wire 21 which has a retained portion 21a that extends beyond the ends of the plurality of superconducting tapes 11. A fixing member 30 is attached to the retained portion 21a.

[0127] (15) The coil proposed in this disclosure comprises a coil support 90 and a plurality of superconducting cables 10 as described in any of (10) to (14) arranged along the coil support 90.

[0128] (16) The cable structures (100 and 200) proposed in this disclosure include superconducting cables 10, 10A, 10B, and 10C as described in any of (10) to (14), a plurality of connecting superconducting tapes 11A and 11B extending in the width direction of the superconducting tape 11 and stacked in the tape stacking direction, and a pressure screw 56 provided on the protective member 50A. Each connecting superconducting tape 11A and 11B is positioned between two superconducting tapes 11 that overlap in the tape stacking direction. The pressure screw 56 applies pressure in the tape stacking direction to the plurality of superconducting tapes 11 and the plurality of connecting superconducting tapes 11A and 11B. This ensures good adhesion between the superconducting tape 11 and the connecting superconducting tapes 11A and 11B, and reduces electrical resistance between them.

[0129] In the structure of (16), the two superconducting cables may be connected in their extension direction. That is, the cable structure proposed in this disclosure may include a first superconducting cable comprising one or more superconducting tapes 11 stacked in the tape stacking direction, a second superconducting cable comprising one or more superconducting tapes 11 stacked in the tape stacking direction, and a pressurizing structure provided on a protective member. The first superconducting cable and the second superconducting cable may face each other in their extension direction. A connection region may be formed inside the protective member in which at least a portion of one or more superconducting tapes of the first superconducting cable and at least a portion of one or more superconducting tapes of the second superconducting cable overlap each other. The pressurizing structure may apply pressure to the connection region in the tape stacking direction. This ensures close contact between the first superconducting cable 11 and the second superconducting cable and reduces electrical resistance between them.

[0130] In the cable structure of (17) and (16), a second reinforcing wire 22 is placed between the pressure screw 56 and the multiple superconducting tapes 11, extending in the direction of extension of the superconducting cable 10 and being flexible. This allows the force acting from the pressure screw 56 to be distributed by the second reinforcing wire 22.

[0131] (18) The fusion reactor proposed in this disclosure has a coil as described in (8) or (15).

[0132] [Other] The superconducting cables, coils, cable structures, and fusion reactors proposed in this disclosure are not limited to the examples described above, and various modifications may be made.

[0133] For example, the superconducting cable 10 had a plurality of stacked first reinforcing wires 21. However, the number of first reinforcing wires 21 may be just one. Also, the superconducting cable 10 had a plurality of stacked second reinforcing wires 22. However, the number of second reinforcing wires 22 may also be just one.

[0134] Furthermore, the superconducting cable 10 had a plurality of protective members 50 arranged in the direction of extension of the superconducting cable 10. Instead of such protective members 50, the superconducting cable 10 may have a tube extending in the direction of extension of the superconducting cable 10.

[0135] Furthermore, the superconducting cables 10B and 10C are connected by one or more connecting superconducting tapes 11B that extend in the width direction of the superconducting cables 10B and 10C and are laminated in the tape lamination direction. However, the two superconducting cables 10 may be connected to each other in the direction in which they extend. In this case, at least a portion of one or more superconducting tapes of the first superconducting cable and at least a portion of one or more superconducting tapes of the second superconducting cable form a connection region (not shown) where they overlap each other. The pressurizing structure provided in the protective member applies pressure to the connection region in the tape lamination direction. In this way, the two superconducting cables can be connected in the direction in which they extend.

[0136] Furthermore, the superconductors in the superconducting cables and cable structures proposed in this disclosure do not necessarily have to be in the form of a tape. For example, the superconductor may be a wire having a circular cross-section. Alternatively, the superconductor may be a wire whose thickness in the lamination direction is greater than its width (size in the direction perpendicular to the cable's extension direction).

[0137] 10, 10A, 10B, 10C, 10E, 10F: Superconducting cable, 11, 11_1, 11_2: Superconducting tape, 11A, 11B: Connecting superconducting tape, 11a: Stabilizing film, 11b: Substrate, 11c: Intermediate layer, 11d: Superconducting layer, 11e: Protective layer, 21: First reinforcing wire, 21a: Retained part, 21a: Retained part, 21c: Through hole, 22: Second reinforcing wire, 22a: Retained part, 22c: Hole, 30, 30A, 30B: Fixing member, 31: Main body part, 31a: First groove, 31b: Second groove, 31 c: Third groove, 31c: Through hole, 32: Cover, 33: Pressing member, 34: Connecting pin, 35: Fixing screw, 41: Cooling pipe, 50・50A: Protective member, 50e: Opening, 51・52・53・54: Partial protective member, 53a: Upper wall, 53b: Side wall, 53e: Opening, 54a: Lower wall, 54b・54c: Side wall, 56: Pressure screw, 57: Support plate, 90: Coil support, 100・200: Cable structure, 300: Pancake coil, B1・B2・B3: Tape bundle, C: Connection area.

Claims

1. A superconducting cable comprising: a plurality of flexible superconductors, each extending in a first direction and stacked in a second direction perpendicular to the first direction; at least one flexible first reinforcing wire, extending in the first direction and overlapping the plurality of superconductors in the second direction; a first fixing member holding a first retained portion which is a part of the first reinforcing wire in the first direction; and a second fixing member holding a second retained portion which is another part of the first reinforcing wire in the first direction.

2. The superconducting cable according to claim 1, wherein the first retained portion of the at least one first reinforcing wire is the portion that extends beyond the position of the first end of the plurality of superconductors toward one side in the first direction.

3. The superconducting cable according to claim 2, wherein the second retained portion of the at least one first reinforcing wire is the portion that extends beyond the position of the second end of the plurality of superconductors toward the opposite side of the first direction from the one side.

4. The superconducting cable according to claim 1, wherein the at least one first reinforcing wire comprises a plurality of first reinforcing wires stacked in the second direction and allowing for relative misalignment in the first direction.

5. The superconducting cable according to claim 1, further comprising at least one second reinforcing wire positioned on the opposite side of the at least one first reinforcing wire, with respect to the plurality of superconductors.

6. The superconducting cable according to claim 1, further comprising at least one cylindrical protective member, wherein the plurality of superconductors and the at least one first reinforcing wire are arranged inside the at least one cylindrical protective member.

7. The superconducting cable according to claim 6, wherein the at least one protective member includes a plurality of protective members arranged in the first direction.

8. A coil comprising a coil support and a superconducting cable according to claim 1, arranged along the coil support, wherein the first fixing member and the second fixing member are fixed to the coil support.

9. A cable structure according to claim 1, comprising: a first superconducting cable which is a superconducting cable as described in claim 1; a second superconducting cable which is a superconducting cable as described in claim 1; and a connecting superconductor, wherein each of the first superconducting cable and the second superconducting cable has a connection region in a part of the first direction, and the connection region of the first superconducting cable and the connection region of the second superconducting cable are aligned in the width direction of the superconductor and are connected to each other via the connecting superconductor.

10. A superconducting cable comprising: a plurality of flexible superconductors, each extending in a first direction and stacked in a second direction perpendicular to the first direction; at least one flexible first reinforcing wire, extending in the first direction and superimposed on the plurality of superconductors in the second direction; and a plurality of protective members, each formed in a tubular shape, surrounding the plurality of superconductors and the at least one first reinforcing wire, and aligned in the first direction.

11. The superconducting cable according to claim 10, wherein each of the plurality of protective members has a first partial protective member and a second partial protective member that are combined with each other to form a cylindrical shape, and the first partial protective member and the second partial protective member are connected to each other so that the relative positions of the first partial protective member and the second partial protective member change in accordance with the curvature of the superconducting cable.

12. The superconducting cable according to claim 11, wherein at least one of the first partial protective member and the second partial protective member is formed of sheet metal.

13. The superconducting cable according to claim 10, further comprising at least one cooling pipe disposed inside the plurality of protective members and extending along the plurality of superconductors.

14. The superconducting cable according to claim 10, wherein the at least one first reinforcing wire has a retained portion that extends beyond the ends of the plurality of superconductors, and a fixing member is attached to the retained portion.

15. A coil having a coil support and a superconducting cable according to claim 10, arranged along the coil support.

16. A cable structure comprising: a superconducting cable as described in claim 10; one or more connecting superconductors; and a pressurizing structure provided on the protective member, wherein each of the one or more connecting superconductors is positioned between two superconductors aligned in the second direction, and the pressurizing structure applies pressure in the second direction to the plurality of superconductors and the plurality of connecting superconductors.

17. The cable structure according to claim 16, wherein at least one second reinforcing wire extending in the first direction and having flexibility is disposed between the pressurized structure and the plurality of superconductors.

18. A superconducting cable according to claim 1 or 10, wherein each of the plurality of superconductors is a superconducting tape.

19. A fusion reactor having the coil described in claim 8 or 15.

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