Superconducting magnet, plasma device, nuclear fusion apparatus, and coil guide for superconducting magnet

Abstract

Disclosed are a superconducting magnet, a plasma device, a nuclear fusion apparatus, and a coil guide for the superconducting magnet, which make it possible to maintain two or more coils in a pre-designed positional relationship. The present disclosure is a superconducting magnet comprising: a first coil and a second coil which each include a superconducting material; a first coil guide which has a first housing part in which the first coil is housed; and a second coil guide which has a second housing part in which the second coil is housed. The first housing part has a helical shape disposed in a state of surrounding the circumference of a torus space, the second coil guide is indirectly or directly attached to the first coil guide, and the second housing part has a helical shape disposed, along the first housing part, in a state of being separated from the first housing part.

Description

Superconducting Magnet, Plasma Device, Fusion Device, and Coil Guide for Superconducting Magnet

[0001] This application discloses a superconducting magnet, a plasma device, a fusion device, and a coil guide for a superconducting magnet.

[0002] As a coil included in a magnetic confinement type fusion device, there is a helical coil wound in a spiral shape so as to surround the periphery of a toroidal space (see Patent Document 1).

[0003] In addition, there is a helical fusion reactor in which a set of sub-helical coils are arranged along a main helical coil (see Non-Patent Document 1). Non-Patent Document 1 describes that a current flowing in a direction opposite to that of the main helical coil is passed through a set of sub-helical coils.

[0004] Japanese Patent Application Laid-Open No. 11-8148

[0005] Nagato YANAGI, et al., “NITA Coil-Innovation for Enlarging the Blanket Space in the Helical Fusion Reactor)”, Plasma and Fusion Research, The Japan Society of Plasma Science and Nuclear Fusion Research, 2016, Volume 11, P.2405034-1 - P.2405034-4

[0006] A magnetic confinement type fusion device is a device that continuously generates a fusion reaction by confining plasma using magnetic field lines.

[0007] Non-Patent Document 1 described above states that the blanket space inside the toroid can be expanded by passing a current flowing in a direction opposite to that of the main helical coil through a set of sub-helical coils.

[0008] However, Non-Patent Document 1 does not specifically mention how to realize and maintain the positional relationship between the main helical coil and the sub-helical coil.

[0009] Therefore, this application discloses a superconducting magnet, a plasma device, a nuclear fusion device, and a coil guide for a superconducting magnet, which are capable of maintaining two or more coils in a pre-designed positional relationship.

[0010] To solve the above problems, in this disclosure, a second coil guide, which forms a spiral-shaped second storage portion, is indirectly or directly attached to a first coil guide, which forms a spiral-shaped first storage portion arranged to surround the torus space, and which forms a spiral-shaped second storage portion arranged along the first storage portion.

[0011] More specifically, the present disclosure provides a superconducting magnet comprising a first coil and a second coil containing a superconducting material, a first coil guide having a first housing portion housing the first coil, and a second coil guide having a second housing portion housing the second coil, wherein the first housing portion has a helical shape arranged to surround a torus space, the second coil guide is attached indirectly or directly to the first coil guide, and the second housing portion has a helical shape spaced apart from the first housing portion and arranged along the first housing portion.

[0012] If the superconducting magnet is configured such that the second coil guide is attached to the first coil guide, it is possible to maintain the positional relationship between the first coil housed in the first housing of the first coil guide and the second coil housed in the second housing of the second coil guide in a pre-designed positional relationship.

[0013] The second coil guide may be attached to the first coil guide via a first cover that covers the first housing. Even if the second coil guide is attached to the first coil guide via the first cover, it is possible to maintain the positional relationship between the first coil housed in the first housing of the first coil guide and the second coil housed in the second housing of the second coil guide in a pre-designed positional relationship.

[0014] Furthermore, the first coil guide may have a first peripheral edge and a second peripheral edge located on the opposite side of the first peripheral edge via a first housing portion, and the first housing portion may include a first groove in which a first portion of the first coil is housed, a second groove in which a second portion of the first coil is housed, and a partition plate disposed between the first groove and the second groove. This makes it possible to provide structural reinforcement with the partition plate.

[0015] Furthermore, at least one of the first coil and the second coil may include a superconducting wire formed by laminating multiple superconducting tapes, and a protective member arranged to surround the superconducting wire and extending in the direction of the superconducting wire's extension. This makes it easier to house the coil in the coil guide's storage section.

[0016] Furthermore, a hollow space may be interposed between the second housing section and the first housing section. This makes it possible to reduce the weight of the coil guide.

[0017] Furthermore, the first containment section may be located between the torus space and the second containment section. This makes it possible to generate the magnetic field for confining the plasma in the torus space using a coil housed in the first containment section.

[0018] Furthermore, the direction of the first current flowing through the first coil and the direction of the second current flowing through the second coil may be opposite to each other. This makes it possible to expand the blanket space inside the torus space when used in a nuclear fusion device.

[0019] Furthermore, this disclosure may also refer to a plasma device or nuclear fusion device equipped with a superconducting magnet as described above.

[0020] Furthermore, the present disclosure may also provide a coil guide for a superconducting magnet, comprising: a first coil guide having a first housing portion for housing a first coil containing a superconducting material; and a second coil guide having a second housing portion for housing a second coil containing a superconducting material, wherein the first housing portion has a helical shape arranged to surround a torus space, and the second coil guide is indirectly or directly attached to the first coil guide, and the second housing portion has a helical shape spaced apart from the first housing portion and arranged along the first housing portion.

[0021] According to this disclosure, it is possible to maintain two or more coils in a pre-designed positional relationship.

[0022] Figure 2 is a cross-sectional perspective showing an example of the configuration of a magnetic field confinement fusion device according to one embodiment. Figure 3 is a perspective showing an example of the structure of a superconducting magnet according to one embodiment. Figure 4 is a cross-sectional view in a direction perpendicular to the extending direction of the superconducting magnet shown in Figure 2. Figure 3 is an explanatory diagram showing an example of the structure of a superconducting wire included in the coil shown in Figure 3. Figure 4 is an explanatory diagram showing the state in which the superconducting wire shown in Figure 4 is held by a protective member according to this embodiment. Figure 3 is an enlarged cross-sectional view of part A. Figure 3 is an enlarged cross-sectional view of part B. Figure 4 is a perspective view showing a first example of the superconducting magnet shown in Figure 2 attached to a vertical field coil. Figure 9 is a perspective view showing a second example of the superconducting magnet shown in Figure 2 attached to a vertical field coil. Figure 10 is a first diagram showing a modified coil guide and lid. Figure 11 is a second diagram showing a modified coil guide and lid. Figure 12 is a third diagram showing a modified coil guide and lid. Figure 13 is a fourth diagram showing a modified coil guide and lid. Figure 14 is an external view of the coil according to the modified coil. Figure 15 is an internal structure diagram of the coil according to the modified coil. Figure 16 shows a modified example of the structure of a superconducting cable.

[0023] <Definition of Terms> First, we will explain the definitions of the terms used in this application.

[0024] A "nuclear fusion device" is a device that uses nuclear fusion reactions to generate energy and extract it into the environment.

[0025] A "magnetic confinement fusion device" is a nuclear fusion device that employs a method of confining the plasma used to generate a nuclear fusion reaction using magnetic field lines. Magnetic confinement methods include various types, such as "tokamak type" and "helical type," depending on the shape of the magnetic field lines. In this application, the term "magnetic confinement method" is used as a general term for all methods of confining plasma using magnetic field lines.

[0026] In magnetic confinement fusion devices, coils are wound around a torus space to confine the plasma. Fusion devices in which the shape of these coils forms a spiral that encloses the torus space are called "helical" fusion devices.

[0027] In this application, superconductors that exhibit superconductivity at temperatures above 77K are referred to as high-temperature superconductors. Hereafter, the terms "superconducting magnet," "superconductor," "superconducting tape wire," or "superconducting wire" may be used, but all of these refer to materials that include high-temperature superconductors.

[0028] A superconducting tape wire (more specifically, a high-temperature superconducting tape wire) is a tape material in which a superconducting layer (more specifically, a high-temperature superconducting layer) is formed on a metal tape approximately 100 micrometers thick. When superconducting tape wire is used as a coil, multiple superconducting tape wires are stacked and bundled together to form a superconducting wire (more specifically, a high-temperature superconducting wire), and a superconducting wire formed into a coil shape is called a superconducting coil (more specifically, a high-temperature superconducting coil). In the following, the term "coil" will be used simply, but unless otherwise specified, "coil" will mean "high-temperature superconducting coil".

[0029] Furthermore, as will be explained in detail below, when used in applications such as nuclear fusion reactors and high-energy particle accelerators, it is necessary to generate a strong magnetic field. For this reason, the term "coil" in this application may refer to a laminated coil in which multiple superconducting wires are wound in a stacked manner.

[0030] In this application, a "superconducting magnet" used in a plasma device or nuclear fusion device is a structure that includes a coil for generating a magnetic field to confine the plasma, and a coil guide for shaping and maintaining the coil in a helical form. As will be explained below, if the coil guide itself has a helical coil shape, the "superconducting magnet" itself can also be considered a "coil." However, in this application, a coil refers to a linear material in which a superconducting wire made of a superconducting material is protected by a protective member, and the coil and coil guide will be explained separately.

[0031] In the following embodiments, the coil that generates a magnetic field for confining the plasma in a torus space is referred to as the "main coil" or "main helical coil." On the other hand, a coil that is spaced apart from the main helical coil and positioned along it is referred to as a "sub-coil" or "sub-helical coil." The "sub-coil" is a coil that has an auxiliary function for expanding the blanket space and can also be called an "auxiliary coil" or "auxiliary helical coil." The "sub-coil" can also be used to perform a rescue operation that controls the operating current of the main helical coil to prevent quenching of the main helical coil.

[0032] <Magnetic Confinement Fusion Device> Figure 1 is a cross-sectional perspective view showing an example of the configuration of a magnetic confinement fusion device, which is one embodiment of the device. The fusion device 100 shown in Figure 1 is a magnetic confinement fusion device, more specifically, a helical-type fusion device.

[0033] Figure 1 shows the X, Y, and Z directions. The X, Y, and Z directions intersect each other. In the example shown in Figure 1, the X, Y, and Z directions are orthogonal to each other.

[0034] The nuclear fusion apparatus 100 comprises a vacuum vessel 2, a blanket 3, a divertor 5, a superconducting magnet 40, and a cryostat 7. Each of the blanket 3, divertor 5, superconducting magnet 40, and cryostat 7 is located inside the vacuum vessel 2. The divertor 5 is located inside the blanket 3.

[0035] Vacuum vessel 2 is a container for housing components necessary for continuously generating a nuclear fusion reaction. Nuclear fusion reactions use hydrogen isotopes, such as deuterium and tritium, as raw materials. Therefore, the inside of vacuum vessel 2 needs to be maintained in an ultra-high vacuum state (for example, 10⁻⁵ Pa or less) before the operation of the nuclear fusion plasma begins.

[0036] Blanket 3 is a component that constitutes the flow path for the liquid metal 6. The fusion plasma 4 forms an annular (torus shape) in the X-Y plane, which includes the X and Y directions in Figure 1. In the following description, "torus space 4S" refers to the torus-shaped space in which the fusion plasma 4 is confined when the fusion device 100 shown in Figure 1 is in operation.

[0037] The blanket 3 is positioned to sandwich the fusion plasma 4 in either the X or Y direction. In other words, when the fusion device 100 is in operation, the fusion plasma 4 (or torus space 4S) is sandwiched between the blanket 3 in either the X or Y direction.

[0038] In the example shown in Figure 1, the liquid metal 6 flowing inside the blanket 3 is irradiated with neutrons generated by the fusion plasma 4. In other words, the blanket 3 has the function of receiving and shielding from the neutrons generated by the fusion plasma 4.

[0039] The liquid metal 6 acts as a coolant, transferring the heat generated by neutron irradiation to the outside. In other words, the blanket 3 has the function of transferring the thermal energy generated by neutron irradiation to the outside (for example, power generation equipment such as a turbine generator) via the coolant (liquid metal 6).

[0040] Furthermore, when irradiated with neutrons, the liquid metal 6 acts as a fuel source, generating tritium, which is the fuel for the nuclear fusion reaction. Tritium is produced by a spallation reaction caused by neutron irradiation of the lithium contained in the liquid metal 6. In other words, the blanket 3 functions as a raw material supply route for generating the fuel for the nuclear fusion reaction.

[0041] The diverter 5 is a component (heat-receiving device) provided in a portion of the blanket 3 where the divertor plasma 5P contacts. A part of the fusion plasma 4 is connected to a part of the surface of the blanket 3 by magnetic field lines. This is called the divertor plasma. Charged particles in the plasma move along the magnetic field lines. The diverter 5 suppresses the intrusion of impurities into the fusion plasma 4 as charged particles by utilizing this property of the charged particles.

[0042] The diverter 5 is disposed between the blanket 3 and the fusion plasma 4. Therefore, the distance between the diverter 5 and the fusion plasma 4 is short. Thus, as the material constituting the diverter 5, a non-magnetic austenitic steel described later is preferable.

[0043] The superconducting magnet 40 is a component (superconducting electromagnet) for generating magnetic field lines for maintaining the fusion plasma 4 in a pre-designed shape. The superconducting magnet 40 includes a coil formed of a superconducting wire and a coil guide for shaping and maintaining the coil in a designed shape. Details of the superconducting magnet 40 will be described later.

[0044] The cryostat 7 is a container for housing the superconducting magnet 40. Also, the cryostat 7 is a heat shield for maintaining the superconducting state of the superconducting magnet 40.

[0045] <Superconducting Magnet> Figure 2 is a perspective view showing a structural example of the superconducting magnet of the present embodiment. Figure 3 is a cross-sectional view of the superconducting magnet extending in a spiral shape. The cross-section shown in Figure 3 is a cross-sectional view in a direction orthogonal to the extending direction of the superconducting magnet.

[0046] In the following description, directions such as the X direction, Y direction, and Z direction may be used. For example, in FIG. 3, the X direction and Y direction are shown. The X direction and Y direction intersect each other. The X direction and Y direction shown in FIG. 3 do not necessarily coincide with the X direction and Y direction shown in FIGS. 1 and 2. In the examples described below, the X direction is orthogonal to the Y direction. Hereinafter, an X-Y plane including the X direction and Y direction is used as a reference plane, and the Z direction orthogonal to the X-Y plane is described as the thickness direction. In the case of the example shown in FIG. 3, the superconducting magnet 40 extends in the Y direction. Also, the X direction shown in FIG. 3 may be referred to as the width direction of the superconducting magnet 40. However, as shown in FIG. 2, the superconducting magnet 40 has an overall toroidal shape. Therefore, the X direction and Y direction change depending on the position of the cross section. On the other hand, the X-Y plane and the Z direction do not change depending on the position of the cross section.

[0047] As shown in FIG. 2, the superconducting magnet 40 extends spirally. The superconducting magnet 40 included in the fusion device 100 (see FIG. 1) of the present embodiment has a superconducting magnet 40A and a superconducting magnet 40B that extend spirally. In other words, the fusion device 100 of the present embodiment includes a superconducting magnet 40 having a double helical structure.

[0048] In the following description, the detailed structure will be described using the superconducting magnet 40A as a representative example. However, the superconducting magnet 40A and the superconducting magnet 40B have the same structure as each other. Therefore, in the following description, the description of the superconducting magnet 40A can be read as the superconducting magnet 40B.

[0049] As shown in FIG. 3, the superconducting magnet 40A has a coil 41 and a coil 42, a coil guide 43, a lid portion 44, a coil guide 45, and a lid portion 46. Each of the coil guide 43, the lid portion 44, the coil guide 45, and the lid portion 46 is made of steel (for example, stainless steel).

[0050] Each of coils 41 and 42 is an electric wire containing a superconducting material. As will be described in more detail later, each of coils 41 and 42 is a superconducting coil containing multiple stacked superconducting tape wires. An example of the structure of a superconducting wire in which multiple superconducting tape wires are stacked will be described later.

[0051] Coil 41 is the main coil for generating a magnetic field to confine the plasma to a torus space. Coil 42, on the other hand, is a sub-coil positioned separately from and alongside the main coil 41. The sub-coil 42 is an auxiliary coil with an auxiliary function for expanding the blanket space. Coil 42 can also be used to perform a rescue operation, controlling the operating current of coil 41 to prevent quenching of coil 41.

[0052] The coil 42 is positioned spaced apart from the coil 41 and along the coil 41.

[0053] During operation of the nuclear fusion device 100 (see Figure 1), current flows through coil 41 and coil 42, respectively. More specifically, as schematically shown in Figure 2, the direction of the current C41 flowing through coil 41 (see Figure 3) and the direction of the current C42 flowing through coil 42 (see Figure 3) are opposite to each other.

[0054] Furthermore, the value of the current C41 flowing through the main coil, coil 41, is greater than the value of the current C42 flowing through the subcoil, coil 42. As in this embodiment, coils 41 and 42 are arranged along each other, and by flowing current C42 in the opposite direction to the direction in which current C41 flows, the distance between the fusion plasma 4 and the blanket 3 inside the torus space 4S shown in Figure 1 (hereinafter referred to as the blanket space) can be expanded. The blanket space has the role of receiving the kinetic energy of neutrons generated in the fusion reaction and converting it into heat, producing tritium, which is a fusion fuel, through the spallation reaction caused by neutrons striking lithium (brooding blanket), or shielding against neutrons and gamma rays (shielding blanket). For this reason, increasing the blanket space is preferable from the viewpoint of improving fuel production performance, improving the efficiency of heat exchange, or improving shielding performance.

[0055] Thus, by arranging the sub-coil 42 along the extension direction of the main coil 41, the electromagnetic characteristics can be improved (in other words, electromagnetic benefits can be obtained). In this case, the following factors are important in order to obtain the electromagnetic effect as designed.

[0056] In other words, it is important that the positional relationship between coil 41 and coil 42 is within the design tolerance range. For the positional relationship between coil 41 and coil 42 to be within the design tolerance range, it is preferable that the translational properties of coil 41 and coil 42 (that one coil 41 and coil 42 are positioned along the other) are ensured. For this reason, it is preferable that the shapes of coil 41 and coil 42 are as designed. Therefore, a technology is needed to form each of coil 41 and coil 42 as designed. Alternatively, a technology is needed to maintain the formed coils 41 and coil 42 so that they do not deform.

[0057] As a result of the above considerations, the inventors of this invention obtained the superconducting magnet 40 of this embodiment. In the superconducting magnet 40 of this embodiment, as shown in Figure 3, the main coil (coil 41) and sub-coil (coil 42) are each housed in coil guides 43 and 45. Coil 41 can be easily formed into the designed shape by winding it inside the housing portion 41H of coil guide 43. Similarly, coil 42 can be easily formed into the designed shape by winding it inside the housing portion 42H of coil guide 45.

[0058] Furthermore, the coil guide 45 for the sub-coil is fixed to a cover portion 44 which is fixed to the coil guide 43 for the main coil. This makes it possible to maintain the molded coils 41 and 42 so that they do not deform. In addition, coils 41 and 42 can be separated from each other within the design tolerance.

[0059] Furthermore, the coil guide 43 for the main coil, the cover portion 44, and the coil guide 45 for the sub-coil are each formed as separate components and fixed together by fastening means such as bolts or welding. In this case, the coil 41 can be wound around the coil guide 43 before the cover portion 44 and the coil guide 45 are attached, making the winding of the coil 41 easier.

[0060] The coil guide 43, lid 44, coil guide 45, and lid 46 will be described in detail below.

[0061] As shown in Figure 3, the coil guide 43 includes a housing portion 41H in which the coil 41 is housed. The housing portion 41H is a groove formed along the extending direction of the coil guide 43. The coil 41 is wound within the housing portion 41H, which is a groove. Within the housing portion 41H, the coil 41 is wound in a stacked manner.

[0062] In the example shown in Figure 3, five layers of coil 41 are stacked in the thickness direction (Z direction in Figure 3) of the coil guide 43. In the width direction (X direction in Figure 3) of the coil guide 43, the coil 41 is wound around the housing section 41H in four rows. Note that the number of layers and rows of coil 41 are not limited to the example shown in Figure 3, and various modifications are possible. In the following explanation, the terms "number of layers" and "number of rows" may also be used, as well as "number of turns". "Number of turns" is the product of "number of layers" and "number of rows".

[0063] The housing section 41H has a helical shape and is arranged to surround the torus space 4S (see Figure 1). Since the coil 41 is wound around the helical-shaped housing section 41H, the coil 41 itself also has a helical shape. In this embodiment, where the coil 41 is wound around the housing section 41H which is a groove, the shape of the coil 41 can be easily made helical by making the shape of the housing section 41H helical in advance.

[0064] Furthermore, a large current flows through the coil 41 used in the superconducting magnet 40 for nuclear fusion. The electromagnetic force generated due to the large current flowing through the coil 41 is also applied to the coil 41 itself. In the case of a structure in which the coil 41 is wound within a groove-like housing 41H, as in this embodiment, deformation or displacement of the coil 41 can be suppressed even when a large electromagnetic force is generated. Therefore, the strength and distribution of the magnetic field generated by flowing a large current through the coil 41 are stable within a range that has been designed in advance (including an allowable margin).

[0065] In the example shown in Figure 3, the coil guide 43 has a peripheral edge portion 43PF1 and a peripheral edge portion 43PF2 located on the opposite side of the peripheral edge portion 43PF1 via a housing portion 41H. The housing portion 41H includes a groove TR1 in which the first portion of the coil 41 is housed and a groove TR2 in which the second portion of the coil 41 is housed. The housing portion 41H may also include a partition plate 43PW positioned between groove TR1 and groove TR2.

[0066] In the example shown in Figure 3, the housing portion 41H of the coil guide 43 is divided into a plurality of grooves (groove TR1 and groove TR2), and a partition plate 43PW is provided between the plurality of grooves. In this case, the external force applied to the coil 41 can be dispersed via the partition plate 43PW, thereby improving the durability of the superconducting magnet 40 against electromagnetic force.

[0067] The lid portion 44 is a cover member that covers the housing portion 41H. The housing portion 41H (specifically groove TR1 and groove TR2) is entirely covered by the lid portion 44. The lid portion 44 is also positioned to cover the entire coil guide 43. The coil guide 43 and the lid portion 44 are, for example, welded together. In the example shown in Figure 3, the lid portion 44 is welded to the peripheral edge portion 43PF1, the peripheral edge portion 43PF2, and the partition plate 43PW, respectively.

[0068] By covering the entire housing section 41H with the lid 44, damage to the coil 41 when attaching the coil guide 45 on the coil guide 43 can be prevented. Furthermore, by fixing the coil guide 43 and the lid 44 by welding, the lid 44 is firmly fixed to the coil guide 43. In this embodiment, since it is necessary to attach the coil guide 45 on the lid 44, it is preferable that the coil guide 43 and the lid 44 are firmly fixed together.

[0069] Furthermore, as shown in Figure 3, the lid portion 44 is fixed not only to the peripheral portion 43PF1 and the peripheral portion 43PF2 but also to the partition plate 43PW, thereby reinforcing the strength of the partition plate 43PW against external forces generated by passing current through the coil 41 (for example, an external force acting in the X direction as shown in Figure 3).

[0070] As shown in Figure 3, the coil guide 45 has a housing portion 42H in which the coil 42 is housed. The housing portion 42H is a groove formed along the extending direction of the coil guide 45. The coil 42 is wound within the housing portion 42H, which is a groove. Within the housing portion 42H, the coil 42 is wound in a stacked manner.

[0071] In the example shown in Figure 3, two layers of coil 41 are stacked in the thickness direction (Z direction in Figure 3) of the coil guide 45. In the width direction (X direction in Figure 3) of the coil guide 45, the coil 42 is wound around the housing section 42H in four rows. Note that the number of layers and rows of coil 42 are not limited to the example shown in Figure 3, and various modifications are possible.

[0072] However, as described above, coil 41 is the main coil for generating a magnetic field to confine the plasma in a torus space. On the other hand, coil 42 is a sub-coil for improving the electromagnetic properties of the superconducting magnet 40. For this reason, in this embodiment, the number of turns of coil 41 is greater than the number of turns of coil 42. In other words, the depth of the grooves constituting the housing portion 42H of the coil guide 45 is shallower than the depth of the grooves (grooves TR1 and TR2, respectively) constituting the housing portion 41H of the coil guide 43.

[0073] By reducing the number of turns of the sub-coil, coil 42, the size of the coil guide 45 can be reduced. In this embodiment, as described above, since coil 42 is housed in the housing portion 42H of the coil guide 45, it is easy to maintain the positional relationship between coil 41 and coil 42. In other words, in this embodiment, it is easy to control the distance between coil 41 and coil 42 to an appropriate value. Therefore, the number of turns of coil 42 can be reduced, and the size of the coil guide 45 can be reduced.

[0074] Furthermore, as shown in Figure 3, in this embodiment, a hollow space 47 is interposed between the housing portion 42H and the lid portion 44. The presence of the hollow space 47 between the housing portion 42H and the lid portion 44 is preferable because it allows for a reduction in the overall weight of the coil guide 45.

[0075] However, as a modification of this embodiment, there is a case in which the hollow space 47 is not interposed between the housing portion 42H and the lid portion 44. For example, when the distance D1 between coil 41 and coil 42 is a very small value (for example, when the distance D1 is less than the thickness T1 of two layers of coil 42), the effect of weight reduction is small even if a hollow space 47 is provided. In this case, a coil guide 45 with a structure that does not provide a hollow space 47, as shown in Figure 3, is used.

[0076] On the other hand, in this embodiment, as shown in Figure 3, the separation distance D1 is greater than or equal to the thickness T1 of two layers of the coil 42. Therefore, the weight reduction effect by providing the hollow space 47 is significant.

[0077] As described above, in this embodiment, the superconducting magnet 40 has coils 41 and 42 arranged along each other, and by flowing current C42 (see Figure 2) in the opposite direction to the direction in which current C41 (see Figure 2) flows, the blanket space inside the torus space 4S can be expanded. In this case, the sub-coil coil 42 is arranged outside the main coil coil 41. In other words, as shown in Figure 3, the housing section 41H is located between the torus space 4S and the housing section 42H.

[0078] The lid portion 46 is a cover member that covers the housing portion 42H. The housing portion 42H is entirely covered by the lid portion 46. However, the lid portion 46 selectively covers the portion of the coil guide 45 that overlaps with the housing portion 42H. The portion of the coil guide 45 that does not overlap with the housing portion 42H is exposed from the lid portion 46. The coil guide 45 and the lid portion 46 are, for example, welded together.

[0079] By covering the entire housing section 42H with the lid 46, damage to the coil 42 can be prevented when attaching the superconducting magnet 40 to the vertical field coil shown in Figures 8 and 9, which will be described later. If attachment of the superconducting magnet to the vertical field coil, etc., as described later is not considered, a modified structure in which the lid 46 is not attached can be considered.

[0080] In the example shown in Figure 3, the coil guide 45 comprises a main body portion 45B including a housing portion 42H, and a flange portion 45F protruding from the main body portion. The main body portion 45B is the part of the coil guide 45 that is positioned on the coil guide 43 (more specifically, on the lid portion 44). The width of the main body portion 45B (length in the X direction in Figure 3) is the same as the width of the coil guide 43 (length in the X direction in Figure 3).

[0081] The flange portion 45F protrudes from the main body portion 45B in the X direction. The flange portions 45F are located on both sides of the main body portion 45B. The flange portions 45F are formed at the position furthest from the cover portion 44 of the coil guide 45.

[0082] <Examples of Coil Structures> Next, examples of the structures of coil 41 and coil 42 shown in Figure 3 are described. In this embodiment, coil 41 and coil 42 are shown as having the same structure, but in this disclosure, they do not have to have the same structure. In the following description, coil 41 will be taken up as a representative example, but in the following description, the term "coil 41" can be replaced with "coil 42".

[0083] Figure 4 is an explanatory diagram showing an example of the structure of the superconducting wire included in the coil shown in Figure 3. As shown in Figure 4, the coil 41 is a superconducting wire 10 that includes a plurality of stacked superconducting tape wires 11 and a metal strip 12 wound around the stack 11A of the plurality of superconducting tape wires 11. Figure 4 illustrates a state in which 152 superconducting tape wires 11 are stacked, but the number of stacked superconducting tape wires is not limited to the example shown in Figure 4 and can be determined according to the size of the coil or the specification of the current value to be passed through the coil. For example, as a modification of this embodiment, the number of stacks of the stack 11A of superconducting tape wires 11 may be 151 or less, or 153 or more.

[0084] The superconducting tape wire 11 is a tape wire in which a superconducting layer (more specifically, a high-temperature superconducting layer) is formed on a metal tape of about several tens of micrometers in thickness. The thickness and width of the superconducting tape wire 11 are examples, and various modifications can be applied. Each of the multiple superconducting tape wires 11 is not bonded to each other, but is stacked in a manner that allows them to shift relative to one another. This makes it possible to form the superconducting wire 10, which is a stack 11A of multiple superconducting tape wires 11, into a shape such as a coil. Although not shown in the figures, as a modification from Figure 4, the stack 11A of multiple superconducting tape wires 11 may be bound together using a wire or the like (not shown). In this case, the handling of the stack 11A is improved. On the other hand, from the viewpoint of improving the degree of freedom of movement of the multiple superconducting tape wires 11 within the tube made of the metal strip 12, it is preferable that the stack 11A of multiple superconducting tape wires 11 is not bound together as in this embodiment.

[0085] A laminate 11A of multiple superconducting tape wires 11 is inserted into a metal strip 12 that is molded into a tube shape. In the example shown in Figure 4, the thickness of the metal strip 12 is, for example, about 100 μm to several hundred μm, and the width is about 3 to 5 mm. Also, in the cross-sectional view shown in Figure 3, which will be described later, the metal strip 12 is molded to form a cylindrical shape. Hereinafter, the structure composed of the metal strip 12 may be referred to as a tube. The outer diameter of the tube is, for example, 23 mm, and the inner diameter is, for example, 22 mm. The tube is a cylindrical metal body, but with this thickness, it is possible to mold the tube into a coil shape. The metal strip 12 functions as a binding member that bundles the laminate 11A of multiple superconducting tape wires 11 together so that they do not scatter. However, each of the multiple superconducting tape wires 11 can move to some extent freely within the tube formed by the metal strip 12.

[0086] In the example shown in Figure 4, the shape of the metal strip 12 surrounding the laminate 11A is spring-shaped, with gaps between adjacent metal strips 12. In some cases, after winding a coil around the coil guide 43 or coil guide 45 shown in Figure 2, the laminate 11A of multiple superconducting tape wires 11 may be molded using a molding member. In this case, an opening is required to introduce the molding member into the tube of the metal strip 12. As shown in Figure 4, if gaps are provided between adjacent metal strips 12, the molding member can be introduced through these gaps to mold the laminate 11A of multiple superconducting tape wires 11.

[0087] As shown in Figure 4, the superconducting wire 10 has cooling tubes 13 and spacers 14 positioned next to the laminate 11A of superconducting tape wires 11. In the example shown in Figure 4, multiple (two in Figure 4) cooling tubes 13 and multiple (two in Figure 4) spacers 14 are positioned next to the laminate 11A of multiple superconducting tape wires 11.

[0088] The cooling tube 13 is a tube that serves as a flow path for the refrigerant and is arranged along the laminate 11A of multiple superconducting tape wires 11. Liquid hydrogen or gaseous helium at a temperature of approximately 20 K (Kelvin) flows through the cooling tube 13 as a refrigerant. The outer diameter of the cooling tube 13 is, for example, 8 mm, and the inner diameter is, for example, 7 mm. The wall thickness of the cooling tube 13 is 1 mm. With this thickness, even if the cooling tube 13 is a metal pipe, it can be deformed to conform to the shape of the superconducting wire 10. In addition, a bellows-shaped pipe may be used from the viewpoint of improving the flexibility of the cooling tube 13. As in this embodiment, by arranging the cooling tube 13 next to the laminate 11A of superconducting tape wires 11, the cooling efficiency of the superconducting tape wires 11 can be improved.

[0089] The spacer 14 is, for example, a wire. The spacer 14 is provided to prevent misalignment from occurring within the tube made of the metal strip 12 in relation to the positional relationship between the laminate 11A of the superconducting tape wires 11 and the plurality of cooling tubes 13.

[0090] The spacer 14 is made of, for example, copper. The spacer 14 may come into contact with the superconducting tape wire 11. For this reason, it is preferable to use a copper wire as the spacer 14 so as not to interfere with the electrical properties of the superconducting tape wire 11.

[0091] The wire diameter of the spacer 14 is, for example, about 2 mm to 3 mm. In the example shown in Figure 4, one spacer 14 is placed in the space surrounded by two cooling tubes 13 and a laminate 11A of superconducting tape wires 11, and another spacer 14 is placed in the space surrounded by two cooling tubes 13 and a metal strip 12.

[0092] However, the number and linearity of the spacers 14 can be modified in various ways depending on the location or cross-sectional area of ​​the space created within the tube. For example, if a gap is created between the metal strip 12 and the laminate 11A of superconducting tape wires 11, the spacers 14 can be inserted into the gap.

[0093] Similarly, there are various variations in the presence and number of cooling tubes 13. For example, in the case of a small superconducting wire with approximately 30 layers of superconducting tape wire 11, cooling tubes 13 may not be provided. Also, there may be one cooling tube 13, or three or more cooling tubes 13.

[0094] Each of the superconducting tape wires 11, the laminate 11A, the cooling tubes 13, and the spacers 14 is inserted into a tubular metal strip 12. Since two cooling tubes 13 and two spacers 14 are arranged inside the tube, the shape of the laminate 11A of superconducting tape wires 11 is such that one side of the laminate 11A has a cross-sectional shape that follows the inner wall of the tube. Since each of the multiple superconducting tape wires 11 is laminated in a state where they are not bonded to each other and can be shifted relative to each other, it is possible to deform them into the shape shown in Figure 4 without any prior molding.

[0095] Another method involves directly winding the superconducting wire 10 shown in Figure 4 onto the housing portion (housing portion 41H or housing portion 42H shown in Figure 3) of the coil guide (coil guide 43 or coil guide 45 shown in Figure 3) to form a coil shape. However, when the superconducting wire 10 is directly wound onto the core material of the coil, the superconducting wire 10 may be damaged during the winding process. Also, when winding multiple layers of superconducting wire 10 onto the housing portion of the coil guide, the positions of the stacked superconducting wires 10 may shift.

[0096] Therefore, from the viewpoint of suppressing damage to the superconducting wire 10, or from the viewpoint of improving the shape retention of the superconducting wire 10 after it has been formed into a coil shape, it is preferable that each of the coils 41 and 42 is equipped with a protective member 200 arranged to surround the superconducting wire 10, as shown in Figure 5.

[0097] Figure 5 is an explanatory diagram showing the superconducting wire shown in Figure 4 being held by the protective member according to this embodiment. Figure 6 is an enlarged cross-sectional view of part A in Figure 5. Figure 7 is an enlarged cross-sectional view of part B in Figure 5.

[0098] As shown in Figure 5, the protective member 200 of this embodiment has a plurality of blocks 20 for holding a superconducting wire 10, which is a linear material, so as to surround it, and wires 30 that engage with the plurality of blocks 20. In Figure 5, there are three visible wires 30, but in this embodiment, the protective member 200 has, for example, four wires 30. Each of the plurality of wires 30 is made of metal. Examples of metal materials that make up the wires 30 include so-called stainless steel (e.g., SUS304), titanium (Ti), or titanium alloys. The diameter of the wires 30 is, for example, about 2 mm.

[0099] The protective member 200 of this embodiment is divisible into a plurality of blocks 20, and the plurality of blocks 20 are connected via wires 30. Therefore, when winding the protective member 200 (in other words, the linear material with the protective member) holding the superconducting wire 10 around, for example, the core material of a coil, gaps can be created at the boundaries of the plurality of blocks 20 as needed. This makes it possible to deform the protective member 200 and wind it around the housing portion 41H (or housing portion 42H) of the coil guide 43 (or coil guide 45) shown in Figure 3. In other words, the plurality of blocks 20 have a structure that can be deformed like a spine.

[0100] The wire 30 functions as a reinforcing member to prevent damage to the superconducting wire 10 caused by tensile forces when the superconducting wire 10 housed in the protective member 200 is wound around the coil guide 43 (see Figure 2) or coil guide 45 (see Figure 2). For this reason, the wire 30 is arranged to extend in the same direction as the extension direction of the superconducting wire (in the case of Figure 5, the X direction). At least one wire 30 is sufficient, but as shown in Figure 5, it is preferable to have multiple wires 30 in order to increase the reinforcing strength of the superconducting wire 10.

[0101] Each of the multiple blocks 20 includes, as shown in Figure 5, a holding space 21 for holding the superconducting wire 10, a roof portion 22 covering the holding space 21, a bottom portion 23 located on the opposite side of the roof portion 22 via the holding space 21, and a side wall portion 24 connected to the roof portion 22 and the bottom portion 23, respectively.

[0102] Each of the roof portion 22, bottom portion 23, and side wall portion 24 is made of a metal material. Examples of metal materials that make up the roof portion 22, bottom portion 23, and side wall portion 24 include titanium (Ti) or titanium alloys. In particular, in the case of protective members for linear materials through which large currents flow, such as the superconducting wire 10, it is preferable that the material be non-magnetic. Considering the hardness, workability, and non-magnetic properties of the material, in addition to the titanium alloys mentioned above, stainless steel (e.g., SUS304) can also be used to form the roof portion 22, bottom portion 23, and side wall portion 24.

[0103] Each of the multiple blocks 20 is assembled to surround the superconducting wire 10. Furthermore, each of the multiple blocks 20 extends in the direction of extension of the superconducting wire 10 (the X direction in the example shown in Figure 5). Additionally, the multiple blocks 20 are arranged along the direction of extension of the superconducting wire 10 (the X direction in the example shown in Figure 5).

[0104] Furthermore, lead members 50 are positioned at the ends of the array of multiple blocks 20. The laminate 11A of the superconducting tape wires 11 of the superconducting wire 10 is electrically connected to the lead members 50. The lead members 50 include, for example, an upper plate 51 and a lower plate 52. The laminate 11A of the superconducting tape wires 11 of the superconducting wire 10 is sandwiched and fixed between the upper plate 51 and the lower plate 52 of the lead members 50. The current flowing through the coil 41 is supplied to the superconducting wire 10 via the lead members 50.

[0105] As shown in Figure 6, the coil 41 is wound in multiple layers within the housing section 41H. Although Figure 6 shows two layers, in this embodiment, it is stacked in five layers as shown in Figure 3. The stacked structure of the coil 41 shown in Figures 3 and 6 is obtained by winding the coil 41, to which the protective member 200 consisting of multiple blocks 20 shown in Figure 5 is attached, along the groove TR1 (in other words, the housing section 41H) shown in Figure 3.

[0106] The shape of the groove TR1 (in other words, the housing portion 41H) is pre-formed to conform to the shape of the block 20 of the protective member 200 that forms the outer shape of the coil 41. As a result, as shown in Figure 6, the gap (clearance) between the laminated coil 41 and the housing portion 41H can be reduced. This allows for high-precision positioning of the superconducting wire 10 in the housing portion 41H after the coil 41 has been wound around it, in this embodiment. In other words, the coil 41 can be easily formed into the designed shape by winding it inside the housing portion 41H of the coil guide 43. Furthermore, the small gap (clearance) between the laminated coil 41 and the housing portion 41H prevents deformation of the coil 41 after it has been formed.

[0107] Similarly, as shown in Figure 7, the coil 42 is wound in multiple layers within the housing 42H. In the examples shown in Figures 3 and 7, the coil 42 is stacked in two layers. The stacked coil structure shown in Figures 3 and 7 is obtained by winding the coil 42, to which the protective member 200 consisting of multiple blocks 20 shown in Figure 5 is attached, along the housing 42H shown in Figure 3.

[0108] The shape of the housing portion 42H is pre-formed to conform to the shape of the block 20 of the protective member 200 that forms the outer shape of the coil 42. Therefore, as shown in Figure 7, the gap (clearance) between the laminated coil 42 and the housing portion 42H can be reduced. As a result, in this embodiment, the position of the superconducting wire 10 in the housing portion 42H after the coil 42 has been wound can be positioned with high precision. In other words, the coil 42 can be easily formed into the designed shape by winding it inside the housing portion 42H of the coil guide 45. Furthermore, the small gap (clearance) between the laminated coil 42 and the housing portion 42H prevents deformation of the coil 42 after it has been formed.

[0109] Thus, according to this embodiment, the molding accuracy and shape retention of coil 41 and coil 42 can be improved, and the electromagnetic characteristics already described can be stably improved.

[0110] <Vertical Field Coil> Next, we will describe the state in which the superconducting magnet 40 shown in Figure 2 is attached to a vertical field coil. Figure 8 is a perspective view showing a first example of the state in which the superconducting magnet shown in Figure 2 is attached to a vertical field coil. Figure 9 is a perspective view showing a second example of the state in which the superconducting magnet shown in Figure 2 is attached to a vertical field coil.

[0111] As shown in Figures 8 and 9, the nuclear fusion apparatus 100 has a plurality of vertical field coils 60 in addition to the superconducting magnet 40 described using Figure 2. The vertical field coils 60 are coils that generate a magnetic field extending in the vertical direction.

[0112] In this embodiment, the superconducting magnet 40 and the multiple vertical field coils 60 are described separately. However, since each of the multiple vertical field coils 60 is a coil for generating a magnetic field to control the plasma, the superconducting magnet 40 and the multiple vertical field coils 60 shown in Figure 8 or Figure 9 can also be defined together as the superconducting magnet.

[0113] The vertical field coil 60 includes an upper outer coil 61 attached to the outside and top of the superconducting magnet 40, a lower outer coil 62 attached to the outside and bottom of the superconducting magnet 40, an upper inner coil 63 attached to the inside and top of the superconducting magnet 40, and a lower inner coil 64 attached to the inside and bottom of the superconducting magnet 40.

[0114] The superconducting magnet 40 is fixed to each of the multiple vertical field coils 60. The fixing method is not particularly limited, but for example, a portion of the coil guide 45 and the cover portion 46 of the superconducting magnet 40 is welded to the vertical field coil 60.

[0115] In this embodiment, the superconducting magnet 40 and the multiple vertical field coils 60 are manufactured separately and fixed together by welding. This is preferable in the following respects.

[0116] In the process of assembling the superconducting magnet 40, a winding machine (not shown) is used to wind the coil 41 onto the coil guide 43 shown in Figure 3, and then the coil 42 onto the coil guide 45. At this time, if the multiple vertical field coils 60 shown in Figure 8 or Figure 9 and the coil guide 45 shown in Figure 3 are formed as a single unit, winding the coil 42 becomes difficult.

[0117] On the other hand, as in this embodiment, when the superconducting magnet 40 and the multiple vertical field coils 60 are manufactured as separate components, the coils 42 can be wound around the coil guide 45 before the multiple vertical field coils 60 are fixed to the coil guide 45. Therefore, the winding work of the coils 42 is easy.

[0118] Furthermore, the superconducting magnet 40 and the multiple vertical field coils 60 are heavy. Therefore, when winding the coils with the superconducting magnet 40 and the multiple vertical field coils 60 integrated together, it is necessary to support the heavy objects while winding the coils.

[0119] On the other hand, as in this embodiment, when the superconducting magnet 40 and the multiple vertical field coils 60 are manufactured as separate components, only the superconducting magnet 40 needs to be supported when winding the coils. Therefore, the weight load on the equipment performing the winding work can be reduced.

[0120] Each of the superconducting magnets 40 and the multiple vertical field coils 60 shown in Figures 8 and 9 is supported on a base plate fixed to a frame (not shown). The coil winding operation is performed, for example, with the superconducting magnet 40 supported on the base plate.

[0121] Coils 41, 42 and the vertical field coil 60 are connected to a predetermined power source (not shown), allowing current to flow as indicated by the arrows labeled C41 and C42 in Figure 2. Coils 41, 42 and the vertical field coil 60 are located inside a cryostat 7, and by placing the inside of the cryostat 7 at an extremely low temperature (e.g., 4K, 20K), they become superconducting, allowing current to flow up to the critical current. The predetermined power source refers to a power supply unit for supplying appropriate power to the coils, and examples include power converters, transformers, and various other power supply equipment that convert power supplied from the in-house power system laid out inside the building of the fusion apparatus 100. The in-house power supply system that supplies power to the power supply unit is connected to an external power supply system and the in-house main generator, etc. When the fusion device 100 is generating power, the power generated by the in-house main generator is supplied to various electrical equipment in the in-house, such as the power supply units for coils 41 and 42 and the power supply unit for the vertical field coil 60. When the fusion device 100 is not generating power, power supplied from the external power supply system is supplied to the various electrical equipment in the in-house.

[0122] Coils 41, 42 and the vertical field coil 60 can be connected to a single power supply unit. This configuration reduces the number of components compared to having multiple power supply units for the coils, enabling a more compact fusion device 100. In this case, the power supply unit can be connected to coil 41, and the circuit can be configured to return to the power supply unit via coil 42, the upper outer coil 61, the lower outer coil 62, the upper inner coil 63, and the lower inner coil 64.

[0123] Furthermore, the fusion device 100 can also be equipped with multiple power supply units. For example, if there are two power supply units, the first power supply unit is connected to coil 41 and a first circuit is configured so that the power returns to the first power supply unit via coil 42, some of the superconducting wires (coils) constituting the upper outer coil 61, some of the superconducting wires (coils) constituting the lower outer coil 62, the upper inner coil 63, and the lower inner coil 64. The second power supply unit can be configured to return to the second power supply unit via the remaining superconducting wires (coils) constituting the upper outer coil 61 and the remaining superconducting wires (coils) constituting the lower outer coil 62. By configuring it in this way, the controllability of the magnetic axis of the magnetic field generated in the fusion device 100 is improved. Also, in this case, the capacity of the second power supply unit can be made less than the capacity of the first power supply unit to stably control the magnetic field. By configuring it in this way, a fusion device 100 with low power consumption in order to generate a stable magnetic field can be realized. For example, the capacity of the first power supply unit is 150kA and the capacity of the second power supply unit is 25kA.

[0124] Furthermore, coils 41 and 42, the upper outer coil 61, the lower outer coil 62, the upper inner coil 63, and the lower inner coil 64 are each connected to separate power supply units, which can then constitute the first, second, third, and fourth circuits, respectively. This configuration improves the controllability of the magnetic axis of the magnetic field generated within the fusion device 100.

[0125] The present invention is not limited to the embodiments and examples described above, and can be modified in various ways without departing from its spirit. For example, the detailed structures of coils 41 and 42 described with reference to Figures 4 to 7 are just examples, and various modifications can be applied.

[0126] Furthermore, there are various modifications to the shape of the coil guide 43 and the coil guide 45 shown in Figure 3, for example.

[0127] Figure 10 is the first diagram showing modified coil guides 43, 45 and lid 44. The coil guide 43 described above may omit the partition plate 43PW, for example, as shown in Figure 10. The coil guide 45 may also be configured not to form a hollow space 47, for example, as shown in Figure 10. If the coil guide 45 does not form a hollow space 47, the coil guide 45 can also perform the function of the lid 44, making it possible to omit the lid 44, as shown in Figure 10. Even if at least one of the coil guides 43 and 45 is modified in this way, it is possible to maintain the positional relationship between the coil 41 housed in the housing portion 41H of the coil guide 43 and the coil 42 housed in the housing portion 42H of the coil guide 45.

[0128] Figure 11 is a second diagram showing a modified example of the coil guides 43, 45 and the cover portion 44. The hollow space 47 described above may be formed by the cover portion 44 instead of the coil guide 45, as shown in Figure 11. In this case, the cover portion 44 will have a U-shaped cross-section. Even when the cover portion 44 forms the hollow space 47, it is possible to maintain the positional relationship between the coil 41 housed in the housing portion 41H of the coil guide 43 and the coil 42 housed in the housing portion 42H of the coil guide 45.

[0129] Incidentally, since the coils 41 and 42 are wound in a spiral shape to surround the torus space 4S, the stacking direction of the superconducting tape wire 11 laminate 11A does not necessarily have to coincide with the direction of the center of the torus space 4S. For example, if the stacking direction of the superconducting tape wire 11 laminate 11A coincides with the principal normal vector of the curve drawn by the coils 41 and 42, the deformation force acting on the superconducting tape wire 11 in the in-plane direction can be suppressed. In this way, to tilt the stacking direction of the superconducting tape wire 11 laminate 11A with respect to the direction of the center of the torus space 4S, the bottom surfaces of the housing portions 41H and 42H formed by the coil guides 43 and 45 can be tilted.

[0130] Figure 12 is a third figure showing modified coil guides 43, 45 and lid 44. In the modified form shown in Figure 12, the bottom surface of the housing portion 41H of the coil guide 43 is inclined with respect to the direction of the center of the torus space 4S. For example, by forming the housing portion 41H of the coil guide 43 in this way, it is possible to make the stacking direction of the laminated body 11A of the superconducting tape wire 11 of the coil 41 coincide with the principal normal vector of the curve drawn by the coil 41. When the stacking direction of the laminated body 11A of the superconducting tape wire 11 of the coil 41 coincides with the principal normal vector of the curve drawn by the coil 41, it is possible to suppress the deformation force acting on the superconducting tape wire 11 of the coil 41 in the in-plane direction. Furthermore, even with such modified forms, it is possible to maintain the positional relationship between the coil 41 housed in the housing portion 41H of the coil guide 43 and the coil 42 housed in the housing portion 42H of the coil guide 45.

[0131] Figure 13 is a fourth figure showing modified configurations of the coil guides 43, 45 and the lid portion 44. In the modified configuration shown in Figure 13, both the bottom surface of the housing portion 41H of the coil guide 43 and the bottom surface of the housing portion 42H of the coil guide 45 are inclined with respect to the direction of the center of the torus space 4S. For example, by forming the housing portion 41H of the coil guide 43 and the housing portion 42H of the coil guide 45 in this manner, it becomes possible to make the stacking direction of the laminated body 11A of the superconducting tape wires 11 of each coil 41, 42 coincide with the principal normal vector of the curve drawn by each coil 41, 42. When the stacking direction of the laminated body 11A of the superconducting tape wires 11 of each coil 41, 42 coincides with the principal normal vector of the curve drawn by each coil 41, 42, it becomes possible to suppress the deformation force acting on the superconducting tape wires 11 of each coil 41, 42 in the in-plane direction. Furthermore, even with such modified configurations, it is possible to maintain the positional relationship between the coil 41 housed in the housing portion 41H of the coil guide 43 and the coil 42 housed in the housing portion 42H of the coil guide 45.

[0132] Furthermore, although various modifications have been described above, a part of the embodiment can be applied in combination with other embodiments. For example, the above embodiment or modification is not limited to one with two coils, but may have three or more coils. Also, this embodiment may be understood as a superconducting magnet 40 alone, a plasma device using the superconducting magnet 40, or a coil guide for the superconducting magnet 40.

[0133] Furthermore, although this embodiment illustrates coils 41 and 42 formed by a laminate 11A of stacked superconducting tape wires 11, the disclosure is not limited to this form. Coils formed by non-laminated wires may be housed in the coil guides 43 and 45.

[0134] Furthermore, although this embodiment shows an example where the coil guides 43 and 45 are separate components, the disclosure is not limited to this form. The coil guides 43 and 45 may be molded as a single unit.

[0135] <Modifications of the coil> In this embodiment, coils 41 and 42 are shown as being formed by winding a metal strip 12 around a laminate 11A of superconducting tape wires 11, but this disclosure is not limited to such forms. Coils 41 and 42 may be, for example, the following forms.

[0136] Figure 14 is an external view of a modified coil (hereinafter referred to as the "superconducting cable"). Figure 15 is an internal structure diagram of the modified coil. The superconducting cable H10 in this modified version is a superconducting coil that can be used in the nuclear fusion device 100, similar to the coils 41 and 42 in the above embodiment, and includes a plurality of stacked superconducting tape wires, etc.

[0137] For example, as shown in Figure 14, the superconducting cable H10 has a plurality of protective members H50 arranged in the direction of extension of the superconducting cable H10. Each protective member H50 is formed in a cylindrical shape with a substantially rectangular cross-section by combining a first partial protective member H51 and a second partial protective member H52 and connecting them with connecting shafts H59b and H59c. The fact that the protective members H50 have a substantially rectangular cross-section makes it easy to arrange multiple superconducting cables H10 at high density.

[0138] Inside the protective member H50, a superconducting tape H11, reinforcing wires H21 and H22, and a cooling pipe H41 are arranged. The superconducting tape H11, like the superconducting tape wire 11 in the above embodiment, is flexible so that it can be bent along the shape of a coil, and for example, tens to hundreds of sheets are stacked in the tape stacking direction without being fixed to each other. This ensures the flexibility of the entire stack of superconducting tape H11. The reinforcing wires H21 and H22 are also tape-shaped like the superconducting tape H11, and several to tens of sheets are stacked in the tape stacking direction. The cooling pipe H41 is also flexible. The reinforcing wires H21 and H22 are arranged inside the protective member H50 so as to sandwich the superconducting tape H11 and the cooling pipe H41, protecting the superconducting tape H11 and the cooling pipe H41.

[0139] The superconducting cable H10 has such a structure, and multiple block-shaped protective members H50 arranged along the longitudinal direction of the superconducting cable H10 house the superconducting tape H11, reinforcing wires H21, H22, etc., inside without being fixed to each other. As a result, the superconducting cable H10 exhibits flexibility that allows it to be bent along the shape of the coil.

[0140] Note that the structure of the superconducting cable H10 is not limited to the form shown in Figure 15. Figure 16 shows a modified example of the structure of the superconducting cable H10. The structure of the superconducting cable H10 may include, for example, a pressure screw H56 for pressurizing the superconducting tape H11, as shown in Figure 16.

[0141] Even when using such a superconducting cable H10, it is possible to maintain the superconducting cable H10 housed in the coil guide 43 and coil guide 45 in the pre-designed positional relationship.

[0142] 2... Vacuum vessel 3... Blanket 4... Fusion plasma 4S... Torus space 5... Diverter 5P... Diverter plasma 6... Liquid metal 7... Cryostat 10... Superconducting wire 11... Superconducting tape wire 11A... Laminate 12... Metal strip 13... Cooling tube 14... Spacer 20... Block 21... Holding space 22... Roof section 23... Bottom section 24... Side wall section 30... Wire 40, 40A, 40B... Superconducting magnet 41, 42... Coil 41H, 42H... Housing section 43, 45... Coil guide 43PF1, 43PF2... Peripheral section 43PW... Partition plate 44, 46... Lid section 46W... Welding material 45B... Main body section 45F...Flange section 47...Hollow space 50...Lead member 51...Upper plate 52...Lower plate 52...Coil 60...Vertical field coil 61...Upper outer coil 62...Lower outer coil 63...Upper inner coil 64...Lower inner coil 100...Fusion device 200...Protective member C41, C42...Current D1...Separation distance TR1, TR2...Groove H10...Superconducting cable H11...Superconducting tape H21, H22...Reinforcement wire H41...Cooling pipe H50...Protective member H51...First part protective member H52...Second part protective member H56...Pressure screw H59b, H59c...Connecting shaft

Claims

1. A superconducting magnet comprising: a first coil and a second coil containing a superconducting material; a first coil guide having a first housing portion in which the first coil is housed; and a second coil guide having a second housing portion in which the second coil is housed, wherein the first housing portion has a helical shape arranged to surround a torus space; the second coil guide is attached indirectly or directly to the first coil guide; and the second housing portion has a helical shape spaced apart from the first housing portion and arranged along the first housing portion.

2. The superconducting magnet according to claim 1, wherein the second coil guide is attached to the first coil guide via a first lid that covers the first housing portion.

3. The superconducting magnet according to claim 1 or 2, wherein the first coil guide has a first peripheral portion and a second peripheral portion located on the opposite side of the first peripheral portion via the first housing portion, and the first housing portion includes a first groove in which a first portion of the first coil is housed, a second groove in which a second portion of the first coil is housed, and a partition plate disposed between the first groove and the second groove.

4. The superconducting magnet according to any one of claims 1 to 3, wherein at least one of the first coil and the second coil includes a superconducting wire in which a plurality of superconducting tapes are laminated, and a protective member arranged to surround the superconducting wire and extending in the direction in which the superconducting wire extends.

5. A superconducting magnet according to any one of claims 1 to 4, wherein a hollow space is interposed between the second housing and the first housing.

6. The superconducting magnet according to any one of claims 1 to 5, wherein the first housing is located between the torus space and the second housing.

7. The superconducting magnet according to any one of claims 1 to 6, wherein the direction of the first current flowing through the first coil and the direction of the second current flowing through the second coil are opposite to each other.

8. A plasma apparatus comprising a superconducting magnet according to any one of claims 1 to 7.

9. A nuclear fusion apparatus comprising a superconducting magnet according to any one of claims 1 to 7.

10. A coil guide for a superconducting magnet, comprising: a first coil guide having a first housing portion for housing a first coil containing a superconducting material; and a second coil guide having a second housing portion for housing a second coil containing a superconducting material, wherein the first housing portion has a helical shape arranged to surround the periphery of a torus space; and the second coil guide is attached indirectly or directly to the first coil guide, and the second housing portion has a helical shape spaced apart from the first housing portion and arranged along the first housing portion.

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