Helical-type nuclear fusion reactor, vacuum vessel of helical-type nuclear fusion reactor and maintenance method of helical-type nuclear fusion reactor

Abstract

To provide a helical-type nuclear fusion reactor capable of improving efficiency of blanket maintenance / replacement work.SOLUTION: A blanket 50 includes a plurality of module assemblies 50A arranged in a circumferential direction Dr around a vertical center line C1 of a helical coil 30, and each of the plurality of module assemblies 50A includes a plurality of blanket modules 51. Each blanket module 51 is movable upward from a gap A formed in the helical coil 30. A vacuum vessel 20 has an openable / closable movable cover 21 covering an upper side of the helical coil 30 and the plurality of module assemblies 50A. The movable cover 21 is so configured that the entire movable cover 21 moves integrally when the movable cover 21 is opened and closed.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a helical fusion reactor, a vacuum vessel for a helical fusion reactor, and a maintenance method for a helical fusion reactor. [Background technology]

[0002] A helical fusion reactor includes a helical coil made of superconducting wires, a cryostat that insulates the helical coil, and a blanket placed inside the helical coil. The blanket functions to breed tritium, shield against radiation, and convert neutron kinetic energy into thermal energy. Radiation and particles from the plasma enter the blanket and deteriorate the blanket material. Therefore, the blanket requires periodic maintenance and replacement. Non-Patent Document 1 below proposes a blanket composed of multiple modules (blanket modules). Multiple blanket modules are combined together to form a single module assembly. Multiple module assemblies are then arranged around a vertical centerline of the fusion reactor to form a ring-shaped blanket. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] J. Miyazawa, T. Goto, Y. Hamaji and MI Kobayashi, "Coordinated design of the cartridge-type blanket and the ceramic pebble divertor for the helical reactor FFHR-b3", Nuclear Fusion, International Atomic Energy Agency, 18th November 2021, 61, 126062 (2021) Summary of the Invention [Problem to be solved by the invention]

[0004] The helical coils and blanket are placed inside the vacuum vessel. To maintain or replace the blanket, the blanket module must be removed from the vacuum vessel and a new blanket module must be transported inside the vacuum vessel. In order to realize a commercial fusion reactor, the efficiency of such maintenance work is an important issue. [Means for solving the problem]

[0005] An example of a helical-type fusion reactor proposed in this disclosure includes a helical coil, a blanket at least a portion of which is disposed inside the helical coil, and a vacuum vessel containing the helical coil and the blanket. The blanket includes a plurality of module assemblies arranged in a circumferential direction around a centerline along the vertical direction of the helical coil. Each of the plurality of module assemblies includes a plurality of blanket modules. Each blanket module is movable upward through a gap formed in the helical coil. The vacuum vessel includes an openable and closable movable cover covering the upper sides of the helical coil and the plurality of module assemblies. The movable cover is configured so that the entire movable cover moves integrally when opened or closed.

[0006] An example of a helical fusion reactor proposed in this disclosure includes a helical coil, a blanket at least a portion of which is disposed inside the helical coil, and a vacuum vessel containing the helical coil and the blanket. The helical coil includes a first coil upper half, a second coil upper half, and a third coil upper half, which are arranged in a circumferential direction around a centerline of the helical coil along a vertical direction and located above a horizontal plane passing through the center of the helical coil. The blanket includes a plurality of module assemblies arranged in the circumferential direction, each of which includes a plurality of blanket modules. The plurality of module assemblies includes a first module assembly located between the first coil upper half and the second coil upper half in a plan view of the helical coil, and a second module assembly located between the second coil upper half and the third coil upper half in a plan view of the helical coil. The vacuum vessel has an openable and closable movable cover covering at least the top sides of the first module assembly and the second module assembly. The movable cover is configured so that the entire movable cover moves integrally when opened or closed. In this structure, the vacuum vessel may have a plurality of movable covers, and these movable covers may entirely cover the helical coil and the plurality of module assemblies.

[0007] One example of a vacuum vessel proposed in this disclosure is a vacuum vessel for accommodating the helical coil and the blanket in a helical fusion reactor. In the helical fusion reactor, at least a portion of the blanket is disposed inside the helical coil, and the blanket has a plurality of module assemblies arranged in a circumferential direction around a centerline extending vertically through the helical coil, each of the plurality of module assemblies including a plurality of blanket modules, each of which is movable upward through a gap formed in the helical coil. The vacuum vessel has an openable and closable movable cover covering the upper sides of the helical coil and the plurality of module assemblies, and the movable cover is configured so that the entire movable cover moves integrally when opened or closed.

[0008] One example of a vacuum vessel proposed in this disclosure is a vacuum vessel for accommodating the helical coil and the blanket in a helical fusion reactor. In the helical fusion reactor, at least a portion of the blanket is disposed inside the helical coil. The helical coil includes a first coil upper half, a second coil upper half, and a third coil upper half, which are arranged in a circumferential direction around a centerline along the vertical direction of the helical coil and located above a horizontal plane passing through the center of the helical coil. The blanket has a plurality of module assemblies arranged in the circumferential direction, each of which includes a plurality of blanket modules. The plurality of module assemblies includes a first module assembly located between the first coil upper half and the second coil upper half in a plan view of the helical coil, and a second module assembly located between the second coil upper half and the third coil upper half in a plan view of the helical coil. The vacuum vessel has an openable and closable movable cover covering at least the upper sides of the first module assembly and the second module assembly. The movable cover is configured so that the entire movable cover moves integrally when opened or closed. In this structure, the vacuum vessel may have a plurality of movable covers, and the plurality of movable covers may entirely cover the helical coil and the plurality of module assemblies.

[0009] A maintenance method proposed in the present disclosure is a maintenance method for a helical-type fusion reactor in which at least a portion of a blanket is disposed inside a helical coil, the helical coil and the blanket are housed in a vacuum vessel, the vacuum vessel has a movable cover covering the upper side of the helical coil, and the outer periphery of the movable cover is joined to another part of the vacuum vessel. The maintenance method includes the steps of moving a release device along the outer periphery of the movable cover to release the joining between the outer periphery of the movable cover and the other part of the vacuum vessel, opening the movable cover, and using a transport system to pull up a blanket module constituting the blanket from a gap formed in the helical coil.

[0010] According to the above-described helical fusion reactor, vacuum vessel of the helical fusion reactor, and maintenance method of the helical fusion reactor, the blanket maintenance and replacement work can be made more efficient than, for example, a structure in which one movable cover is provided per module assembly. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view showing an example of a helical-type nuclear fusion reactor proposed in the present disclosure. FIG. [Figure 2] 1 is a perspective view of the interior of a fusion reactor bioshield, with half of the bioshield removed. [Figure 3] FIG. 3 is a perspective view of the vacuum vessel and the like shown in FIG. 2, viewed obliquely from below. [Figure 4] FIG. 2 is a perspective view showing a state in which a movable cover of the vacuum vessel is open. [Figure 5] FIG. 2 is an exploded perspective view of the vacuum vessel and the reactor body M housed therein. [Figure 6A] FIG. 2 is a plan view of the vacuum vessel. [Figure 6B] FIG. 2 is a perspective view showing a main part of a vacuum vessel. [Figure 7A] FIG. 2 is a perspective view showing a part of the furnace body. [Figure 7B] FIG. 7B is a perspective view showing the side opposite to the part shown in FIG. 7A. [Figure 8] FIG. 2 is a perspective view showing the module assembly separated from the cryostat. [Figure 9A] 1 is a perspective view showing the helical coil and the module assembly assembled together, with the cryostat omitted in this view. [Figure 9B] FIG. 9B is a perspective view showing the side opposite to the part shown in FIG. 9A. [Figure 10A] FIG. 2 is a perspective view showing a part of a helical coil. [Figure 10B] FIG. 2 is a plan view showing a part of a helical coil. [Figure 10C] FIG. 10B is a view of the part shown in FIG. 10A viewed in the horizontal direction. [Figure 11] FIG. 2 is an exploded perspective view of the upper pool, module assembly, and lower pool. [Figure 12] FIG. [Figure 13A] FIG. 1 is a plan view of two adjacent module assemblies. [Figure 13B] FIG. 2 is a perspective view showing the underside of the module assembly. [Figure 14] 14 is a cross-sectional view of the module assembly and helical coil taken along line XIV-XIV shown in FIG. 13A. [Figure 15A] FIG. 1 is a perspective view showing a portion of a plurality of blanket modules that make up a module assembly. [Figure 15B] FIG. 15B is a perspective view showing the two blanket modules shown in FIG. 15A combined together. [Figure 16] FIG. 1 is a perspective view showing a portion of a plurality of blanket modules that make up a module assembly. [Figure 17] FIG. 10 is a perspective view for explaining a sliding mechanism of a blanket module provided on the upper wall of the cryostat. [Figure 18] FIG. 1 is a flow chart for explaining a maintenance method for a nuclear fusion reactor. DETAILED DESCRIPTION OF THE INVENTION

[0012] The helical fusion reactor, the vacuum vessel of the helical fusion reactor, and the blanket replacement method proposed in this disclosure will be described below. In this specification, the helical fusion reactor 10 shown in FIG. 1 etc. will be described as an example of the helical fusion reactor proposed in this disclosure.

[0013] The reactor body M (see FIG. 5) housed in the vacuum vessel 20 has a helical coil 30. Line C1 shown in FIG. 5 is the center line of the helical coil 30 along the vertical direction, and in the following description, this center line C1 will be referred to as the "vertical center line." The direction indicated by the arrow Dr in FIG. 5 is the circumferential direction around the vertical center line C1, and this direction will be referred to as the "circumferential direction of the reactor body."

[0014] [Overall nuclear fusion reactor] 1, the helical fusion reactor 10 includes the above-mentioned vacuum vessel 20, multiple plasma heating devices 2, a fuel circulation system 3, a liquid breeder circulation system 4, and a bioshield 5. The helical fusion reactor 10 may be installed on land or mounted on a ship.

[0015] A fusion reactor main body M (see FIG. 4) including a helical coil 30, a blanket 50, and the like, which will be described later, is disposed inside the vacuum vessel 20. As shown in FIG. 3, a plurality of vacuum pumps 6 are connected to the bottom of the vacuum vessel 20. The vacuum pumps 6 are, for example, cryopumps, but are not necessarily limited to this. As shown in FIG. 4, the vacuum vessel 20 has a movable cover 21 and a cylindrical outer peripheral wall 22. The movable cover 21 can be opened and closed to allow for maintenance work on the blanket 50 (see FIG. 8) and the like that constitute the reactor main body M. The structure of the vacuum vessel 20 will be described in detail later.

[0016] The plasma heating device 2 is a device for heating plasma, and may be a radio-frequency heating device, a neutral particle injection device, or the like. An electron cyclotron heating device may be used as the radio-frequency heating device, but other types of heating devices may also be used. As shown in FIG. 2, the plasma heating device 2 has a plurality of pipes 2a. The pipes 2a may be connected to the outer peripheral wall 22 of the vacuum vessel 20.

[0017] The fuel circulation system 3 supplies fuel for the nuclear fusion reaction to the reactor body M. The fuel is mainly tritium and deuterium. The fuel circulation system 3, for example, solidifies these fuels as pellets (hydrogen pellets) and injects them into the reactor body M. The fuel circulation system 3 also purifies, compresses, and solidifies gas generated in the blanket 50 (more specifically, gas generated from the liquid breeder material described below), and injects this as fuel into the reactor body M again. As shown in FIG. 2, the fuel circulation system 3 has a plurality of injectors 3a arranged around the vacuum vessel 20. The injectors 3a may be connected to the outer peripheral wall 22 of the vacuum vessel 20.

[0018] The helical fusion reactor 10 utilizes a liquid metal that functions as a breeding material for tritium and as a coolant for the blanket 50. Examples of the liquid metal that can be used include, but are not limited to, liquid lithium, a tin-lead-lithium alloy, and a lithium-lead alloy. The liquid breeder circulation system 4 supplies the liquid metal (liquid breeder) to the upper side of the blanket 50 of the reactor body M.

[0019] The liquid breeder circulation system 4 recovers the liquid breeder that has passed through the blanket 50 from the underside of the blanket 50 and passes it through a heat exchanger 4a (see FIG. 2) and a tritium recovery unit 4b (see FIG. 2). The liquid breeder circulation system 4 then supplies the liquid breeder to the blanket 50 again. The liquid breeder circulation system 4 has a plurality of supply pipes 4c (see FIG. 6B). The supply pipes 4c are connected to the movable cover 21 of the vacuum vessel 20.

[0020] As shown in FIG. 2, the vacuum vessel 20 and the reactor main body M are placed in a bioshield 5 for shielding against radiation and the like. A storage chamber 5a is provided in the bioshield 5 for storing the blanket modules 51 retrieved from the reactor main body M. A transfer system 70 for the blanket modules 51 is installed in the bioshield 5. The removal of the blanket modules 51 from the fusion reactor main body M and the transfer of the blanket modules 51 to the storage chamber 5a are carried out by this transfer system 70. This transfer system 70 will also be described in detail later.

[0021] [Fusion reactor body] As shown in Fig. 7A, the fusion reactor body M has a helical coil 30, a cryostat 40, and a breeder blanket 50. The fusion reactor body M also has an upper pool 61 and a lower pool 62 (see Fig. 11). Fig. 7A shows only a part (50A) of the breeder blanket 50. The parts shown in Fig. 7A are arranged in the circumferential direction Dr of the reactor body M to form an annular breeder blanket 50.

[0022] [Helical coil] As shown in FIG. 10A, the helical coil 30 has a coil support 31. The coil support 31 is double-helix shaped. That is, the coil support 31 has two coil housings 31A and 31B formed along a torus surface centered on a vertical center line C1. Each of the coil housings 31A and 31B has, for example, a plurality of hollow tubes 31a to 31d formed therein. Each of these hollow tubes 31a to 31d houses a superconducting wire (not shown) and a cooling tube (not shown) that serves as a flow path for a refrigerant. For example, liquid helium, liquid hydrogen, liquid nitrogen, water, or the like can be used as the refrigerant.

[0023] The structure of the coil housings 31A and 31B is not limited to the example described here. For example, the helical coil 30 does not need to include cooling pipes. In this case, the hollow tubes 31a to 31d may be filled with a refrigerant. In addition, in the example shown in FIG. 10A, four hollow tubes 31a to 31d are formed in each of the coil housings 31A and 31B, but the number may be less than or more than three.

[0024] As shown in Fig. 10A, the furnace body M has annular vertical magnetic field coils 32A, 32B, 33A, and 33B centered on a vertical center line C1. The vertical magnetic field coils 32A and 32B are formed inside the helical coil 30. The vertical magnetic field coils 33A and 33B are formed outside the helical coil 30. Each of the vertical magnetic field coils 32A, 32B, 33A, and 33B has a coil housing. A superconducting wire (not shown) and a cooling pipe (not shown) for cooling the superconducting wire are housed in a hollow tube formed inside these coil housings.

[0025] [Cryostat] 7A, the cryostat 40 has an upper wall 41 that covers the upper side of the helical coil 30. The cryostat 40 also has an inner wall 42 that is disposed inside the helical coil 30 (on the side of the vertical center line C1) and an outer wall 43 that is disposed outside the helical coil 30 (on the opposite side of the helical coil 30 from the inner wall 42). The cryostat 40 also has a bottom wall 44 that is disposed below the helical coil 30.

[0026] The furnace body M may have n modules. Each module constitutes a portion of the entire furnace body M corresponding to 360 / n degrees. In FIG. 7A, only one module is shown. In the furnace body M, the portions shown in FIG. 7A are arranged in the circumferential direction Dr of the furnace body M to constitute an annular furnace body M (see FIG. 5). Therefore, in a plan view of the furnace body M, the top wall 41 and the bottom wall 44 are annular with the vertical center line C1 as the center, and the inner wall 42 and the outer wall 43 are cylindrical and surround the vertical center line C1.

[0027] As will be described later, the blanket 50 has a plasma-facing wall 50W (see FIG. 11) at its lower part. The plasma-facing wall 50W is disposed inside the helical coil 30 and has a cylindrical shape extending along the circumferential direction Dr of the reactor body M. As shown in FIG. 14, the cryostat 40 has an inner shielding wall 45. The inner shielding wall 45 is formed between the plasma-facing wall 50W and the helical coil 30. The inner shielding wall 45 prevents the helical coil 30 from being irradiated with radiation and particles generated from the plasma.

[0028] The inner shielding wall 45 forms a sealed space isolated from the vacuum vessel 20 between itself and the other walls of the cryostat 40 (i.e., the top wall 41, the inner wall 42, the outer wall 43, and the bottom wall 44). This ensures a high degree of vacuum within the vacuum vessel 20, i.e., in the space inside the plasma-facing wall 50W where plasma is generated. In addition, the helical coil 30 can be insulated from other spaces within the vacuum vessel 20.

[0029] [blanket] The blanket 50 has module assemblies 50A (see FIG. 11). n module assemblies 50A are arranged in the circumferential direction Dr of the reactor body M to form an annular blanket 50 centered on the vertical center line C1 (two module assemblies 50A are arranged in FIG. 13A). In the example described herein, the blanket 50 has ten module assemblies 50A. These ten module assemblies 50A may have the same structure.

[0030] The number of module assemblies 50A may be less than 10 or more than 10. The number of module assemblies 50A may be changed according to the size of the furnace body M and the pitch of the helical coil 30 (the distance between the upper half portions 30a of the coil, which will be described later).

[0031] Each module assembly 50A has m blanket modules 51_1 to 51_9 (see FIG. 12). The m blanket modules 51_1 to 51_9 may have different shapes. In the example described in this specification, each module assembly 50A has nine blanket modules 51. The shapes of the first to ninth blanket modules 51_1 to 51_9 are designed so that they can pass between two adjacent coil upper halves 30a.

[0032] In the following, when these nine blanket modules 51_1 to 51_9 are not to be distinguished from one another, the blanket modules will be referred to as "51."

[0033] 12, each blanket module 51 has, at its bottom, a module lower portion 52. The module lower portion 52 functions as part of an annular plasma-facing wall 50W centered on a vertical centerline C1. Each blanket module 51 has, at its top, a module upper portion 53 supported by the upper wall 41 of the cryostat 40. Each blanket module 51 has a flow path portion 54 extending from the module upper portion 53 toward the module lower portion 52.

[0034] The plasma-facing wall 50W is annular and centered on the vertical center line C1 of the reactor body M. The module lower parts 52 of m blanket modules 51 constituting one module assembly 50A are combined with each other to form a portion of the annular plasma-facing wall 50W (a plasma-facing wall having a width corresponding to 360 / n degrees). As described above, in the example described in this specification, the blanket 50 has 10 module assemblies 50A. Therefore, the module lower parts 52 of each blanket module 51 are combined with each other to form a width corresponding to 36 degrees of the entire plasma-facing wall 50W.

[0035] The number of blanket modules 51 may be less than 9 or more than 9. The number of blanket modules 51 may be changed depending on the size and shape of the module assembly 50A.

[0036] [Structures related to the flow of liquid breeding materials] The interior of each blanket module 51 is configured so that liquid breeding material flows from the module upper portion 53 to the module lower portion 52. As shown in FIG. 11, a liquid breeding material supply port 53a is formed in the module upper portion 53. The supply port 53a is formed on the upper surface of the module upper portion 53. The reactor body M has multiple upper pools 61. The positions of the multiple upper pools 61 correspond to the positions of the multiple module assemblies 50A, respectively. The liquid breeding material is supplied to the upper pool 61 from outside the vacuum vessel 20 through supply pipes 4c (see FIG. 6B). The upper pool 61 is connected to the supply ports 53a of the blanket modules 51 and supplies the liquid breeding material to each blanket module 51. The bottom of the upper pool 61 may be formed with multiple connection pipes 61a (see FIG. 11) connected to the supply ports 53a of the blanket modules 51.

[0037] The flow path 54 (see FIG. 12) between the upper module 53 and the lower module 52 is tubular, and the liquid breeding material flows inside it. The lower module 52 is configured so that the liquid breeding material passes through the inside of the lower module 52 and is exposed from the surface 52g (see FIG. 14, the surface facing the plasma) of the lower module 52. (In FIG. 14, arrow F indicates part of the flow of the leaked liquid breeding material.)

[0038] The module lower portion 52 may be made of, for example, a porous material. The liquid breeding material that has passed through the flow path 54 passes through the porous module lower portion 52 and is exposed from the surface 52g of the module lower portion 52, forming a free surface. This liquid breeding material can therefore function as the first wall. Examples of materials that can be used for the porous module lower portion 52 include titanium, a titanium alloy, and high-manganese steel.

[0039] 14, a lower pool 62 that is open upward is disposed below the module assembly 50A. The opening of the lower pool 62 may be fitted into the lower end of the module assembly 50A. An opening 44a (see FIG. 14) is formed in the bottom wall 44 of the cryostat 40, and the lower pool 62 may be fitted into this opening 44a from below.

[0040] As shown in Figure 14, the liquid breeding material leaking from the surface 52g of the module lower part 52 flows into this lower pool 62. A discharge pipe 62a (see Figure 11) is connected to the lower pool 62. As shown in Figure 3, the discharge pipe 62a may extend from an opening formed in the outer peripheral wall 22 of the vacuum vessel 20 to the outside of the vacuum vessel 20. The liquid breeding material discharged from the lower pool 62 is sent to the heat exchanger 4a and the tritium recovery device 4b (see Figure 2) installed outside the vacuum vessel 20.

[0041] As shown in Figure 13B, multiple blanket modules 51 are combined with each other and have openings 55a formed at their lower ends. (Hereinafter, these openings will be referred to as "discharge openings.") These discharge openings 55a facilitate the smooth flow of liquid breeding material from the surface 52g of the module lower part 52 to the lower pool 62. Furthermore, helium ash and other materials from the divertor plasma formed near the discharge openings 55a of the module lower part 52 can be efficiently discharged to the lower pool 62 together with the liquid breeding material.

[0042] The discharge opening 55a is formed between two adjacent lower coil halves 30b of the helical coil 30. Here, the lower coil halves 30b are portions located below a horizontal plane P1 (see FIG. 10C) passing through the vertical center of the helical coil 30. A gap is formed between the two adjacent lower coil halves 30b. The discharge opening 55a may be formed so that its width increases toward the radially outer side of the reactor body M, in accordance with the gap formed between the two lower coil halves 30b. This allows for smooth flow of the liquid breeding material.

[0043] [Removing the blanket module] Radiation and particles from the plasma enter the lower module 52 of the blanket module 51 and deteriorate the material of the lower module 52. Therefore, periodic replacement and maintenance work is required for the blanket module 51. To make this work more efficient, each blanket module 51 can be moved upward through a gap A (see FIG. 10B) formed in the helical coil 30.

[0044] Specifically, as shown in FIGS. 10B and 10C, the helical coil 30 has multiple coil upper halves 30a arranged in the circumferential direction Dr of the reactor body M. Here, the coil upper halves 30a are portions located above a horizontal plane P1 (see FIG. 10C) passing through the vertical center of the helical coil 30. A gap A (see FIG. 10B) is formed between two adjacent coil upper halves 30a. In a plan view of the helical coil 30, multiple module assemblies 50A are respectively disposed in the multiple gaps A. Each blanket module 51 can be moved upward through this gap A. Furthermore, a blanket module 51 after maintenance or a new blanket module 51 can be moved downward through this gap A.

[0045] [An opening corresponding to gap A is formed in the upper wall of the cryostat] As described above, the upper wall 41 of the cryostat 40 covers the upper side of the helical coil 30. As shown in Fig. 8, the upper wall 41 has an opening 41a formed therein that corresponds to the gap A. The blanket module 51 can be moved up and down through this opening 41a.

[0046] [Bottom of the 1st and 2nd blanket modules] 15A is a module disposed closer to one of the two adjacent coil upper halves 30a. The module lower portion 52 of the first blanket module 51_1 protrudes by a width W1 beyond the flow path portion 54 in the circumferential direction Dr of the reactor body M. As shown in FIG. 9A, the module lower portion 52 is located below the coil upper half portion 30a and overlaps with the coil upper half portion 30a in a plan view of the helical coil 30.

[0047] 15B, the second blanket module 51_2 is combined with the first blanket module 51_1 in the radial direction of the reactor body M. The module lower portion 52 of the first blanket module 51_1 has a substantially U-shape that opens toward the vertical center line C1. In contrast, the module lower portion 52 of the second blanket module 51_2 has a substantially U-shape that opens toward the opposite side (outward) from the vertical center line C1. These two module lower portions 52 are combined with each other to form an annular shape in a cross-sectional view taken along the vertical center line C1.

[0048] The module lower portion 52 of the second blanket module 51_2 protrudes by a width W2 beyond the flow path portion 54 in the circumferential direction Dr of the reactor body M. The module lower portion 52 is located below the coil upper half portion 30a and overlaps with the coil upper half portion 30a in a plan view of the helical coil 30.

[0049] The overhangs (W1 and W2) of the module lower portions 52 of the first and second blanket modules 51_1 and 51_2 can substantially eliminate the gap between the plasma-facing walls 50W formed by two adjacent module assemblies 50A.

[0050] In order to move the first and second blanket modules 51_1 and 51_2 upward from the gap A of the helical coil 30 (in other words, the opening 41a of the cryostat 40), it is necessary to move the blanket modules 51_1 and 51_2 in the circumferential direction Dr of the reactor body M. This movement can be achieved by a first transfer mechanism 71 (see FIG. 3 ) of a transfer system 70 installed in the bioshield 5.

[0051] [Top of the 1st and 2nd blanket modules] A module upper portion 53 of the first blanket module 51_1 is located above the coil upper half portion 30a and overlaps with the coil upper half portion 30a when the helical coil 30 is viewed from above. A flow path portion 54 of the first blanket module 51_1 is disposed along the side surface of the coil upper half portion 30a.

[0052] The module upper portion 53 of each blanket module 51 is supported by the edge of an opening 41a formed in the top wall 41 of the cryostat 40. As shown in FIG. 17 , the top wall 41 may be provided with a slide mechanism that slides the module upper portion 53 in the radial direction of the reactor body M. The slide mechanism may be configured with, for example, a feed screw. For example, a feed screw 49 may be installed in the top wall 41, and a threaded hole 53e may be formed in the module upper portion 53. This slide mechanism allows, for example, the first blanket module 51_1 to move in the radial direction of the reactor body M.

[0053] By combining the radial movement of this blanket module 51, the circumferential movement of the furnace body M in the circumferential direction Dr, and the tilting of the blanket module 51 by the winding device described later, each blanket module 51 can move in the vertical direction while avoiding interference with the upper half of the coil 30a.

[0054] When the first and second blanket modules 51_1 and 51_2 are combined, the module top 53 of the second blanket module 51_2 is supported above the module top 53 of the first blanket module 51_1. Since the module tops 53 of the two blanket modules 51 overlap in this manner, multiple module tops 53 can be supported on the edge of the opening 41a of limited size.

[0055] 15A, a plurality of guided portions 53d may be formed in the module upper portion 53. Each guided portion 53d may be a convex portion protruding downward from the module upper portion 53 or a convex portion protruding from the module upper portion 53 in the circumferential direction Dr of the reactor body M. The guided portions 53d fit into guide portions (concave portions) formed in the upper wall 41 of the cryostat 40, and fix the position of each blanket module 51 at a predetermined appropriate position.

[0056] [Third and fifth blanket modules] 16 are modules arranged on the opposite side of the first and second blanket modules 51_1 and 51_2 in the circumferential direction Dr of the reactor body M. That is, the blanket modules 51_3 and 51_5 are modules arranged closer to the other of the two adjacent coil upper half portions 30a.

[0057] 16, the module lower portion 52 of the fifth blanket module 51_5 has a generally U-shape that opens toward the vertical centerline C1. In contrast, the module lower portion 52 of the third blanket module 51_3 has a generally U-shape that opens toward the opposite side (outward) from the vertical centerline C1. These two module lower portions 52 are combined with each other to form an annular shape in a cross-sectional view taken along the vertical centerline C1.

[0058] 16, the module lower portion 52 of the third blanket module 51_3 protrudes by a width W3 beyond the flow path portion 54. The module lower portion 52 of the fifth blanket module 51_5 protrudes by a width W5. As shown in FIG. 9B, these two module lower portions 52 are located below the coil upper half portion 30a and overlap with the coil upper half portion 30a in a plan view of the helical coil 30.

[0059] The overhangs (W3 and W5) of the module lower portions 52 of the third and fifth blanket modules 51_3 and 51_5 can substantially eliminate the gap between the plasma-facing walls 50W formed by two adjacent module assemblies 50A.

[0060] More specifically, it is possible to substantially eliminate gaps between the module lower portions 52 of the first and second blanket modules 51_1 and 51_2 of one module assembly 50A of two adjacent module assemblies 50A and the module lower portions 52 of the third and fifth blanket modules 51_3 and 51_5 of the other module assembly 50A. This allows the annular plasma-facing wall 50W centered on the vertical center line C1 to be composed only of the blanket modules 51 that can be lifted upward.

[0061] In order to move the third and fifth blanket modules 51_3 and 51_5 upward from the helical coil 30, it is necessary to move the blanket modules 51_3 and 51_5 in the circumferential direction Dr of the reactor body M. This movement can also be achieved by the first transfer mechanism 71 (see FIG. 3 ) of the transfer system 70 installed in the bioshield 5.

[0062] [Top of the third blanket module] 9B, at least a portion of the module upper portion 53 of the third blanket module 51_3 is located above and overlaps with the coil upper half portion 30a. Similarly, a portion of the module upper portion 53 of the fifth blanket module 51_5 is also located above and overlaps with the coil upper half portion 30a.

[0063] The module upper portion 53 of the third blanket module 51_3 is also supported by the edge of an opening 41a formed in the top wall 41 of the cryostat 40. A slide mechanism for sliding the module upper portion 53 of the third blanket module 51_3 may be provided on the top wall 41. The slide mechanism may be constituted by, for example, a feed screw 49. For example, the feed screw 49 may be installed on the top wall 41, and a threaded hole 53e may be formed in the module upper portion 53. This slide mechanism allows the third blanket module 51_3 to move in the radial direction of the reactor body M.

[0064] Similar to the first and second blanket modules 51_1 and 51_2 described above, when the third and fifth blanket modules 51_3 and 51_5 are combined, the module top portion 53 of the fifth blanket module 51_5 is supported above the module top portion 53 of the third blanket module 51_3 (see FIG. 16). Since the module top portions 53 of the two blanket modules 51 overlap in this manner, multiple module top portions 53 can be supported on the edge of the opening 41a of limited size.

[0065] [Other blanket modules] As shown in Figure 13A, the other blanket modules 51 (i.e., the fourth, sixth to ninth blanket modules 51) are arranged between the first and second blanket modules 51_1 and 51_2 installed near one coil upper half 30a and the third and fifth blanket modules 51_3 and 51_5 installed near the other coil upper half 30a.

[0066] Unlike the blanket modules 51 arranged on both sides thereof (i.e., the first to third and fifth blanket modules 51), the fourth and sixth to ninth blanket modules 51 do not need to have the above-mentioned overhangs (W1 to W3, W5). Therefore, the fourth and sixth to ninth blanket modules 51 may be able to move straight up and down.

[0067] [Distance between two adjacent module assemblies] The blanket 50 has n (ten in the example described herein) module assemblies 50A that make one revolution in the circumferential direction Dr of the reactor body M centered on the vertical center line C1. Each module assembly 50A has m (nine in the example described herein) blanket modules 51. The module lower parts 52 of the m blanket modules 51 are combined with each other to form a plasma-facing wall 50W having a width corresponding to 360 / n degrees (36 degrees in the example described herein) around the vertical center line C1.

[0068] Therefore, as shown in Figure 14, when focusing on the cross section of two adjacent module assemblies 50A, the side surfaces 52a and 52b (see Figure 9A) of the lower module part 52 of one module assembly 50A and the side surfaces 52c and 52e (see Figure 9B) of the lower module part 52 of the other module assembly 50A are close to each other. Here, "side surfaces close to each other" means that there is no gap exceeding the clearance required for manufacturing. There does not need to be a blanket between the side surfaces 52a and 52b and the side surfaces 52c and 52e that does not allow upward movement.

[0069] Furthermore, the surface 52g (surface facing the plasma) of the module lower part 52 of one module assembly 50A and the surface 52g of the module lower part 52 of the other module assembly 50A form a continuous curved surface in the circumferential direction Dr of the reactor body M. This allows the liquid breeding material leaking from the surface 52g to flow smoothly to the discharge opening 55a formed at the lower end of the module assembly 50A.

[0070] 7B, the blanket 50 may have a test module 59. Unlike the above-described blanket module 51, this test module 59 may be slidable in the radial direction of the reactor body M. An end 59a (an end closer to the plasma) of this test module 59 does not protrude beyond the position of a surface 52g of the module lower portion 52 into the inside of the helical coil 30.

[0071] The structure of the blanket 50 is not limited to the example described here. For example, each module assembly 50A may have a blanket module that forms part of the plasma-facing wall 50W and is slidable in the radial direction of the reactor body M. That is, the module assembly 50A may have a blanket module 51 that can be pulled upward through the gap A of the helical coil 30, and a blanket module that can be slidable in the radial direction of the reactor body M. In this case, an opening for removing this blanket module from the vacuum vessel 20 may be formed in the outer peripheral wall 22 of the vacuum vessel 20.

[0072] [Vacuum vessel movable cover] 4, the vacuum vessel 20 has an openable and closable movable cover 21 that covers the upper sides of the helical coil 30, the cryostat 40, the blanket 50, etc. The movable cover 21 covers all of the n module assemblies 50A that are arranged in the circumferential direction Dr of the reactor main body M. In other words, the movable cover 21 covers the reactor main body M over an angular range of 360 degrees centered on the vertical center line C1.

[0073] 4, the movable cover 21 may be supported via a hinge 29a disposed on the outside of the outer periphery 21a of the movable cover 21. The movable cover 21 opens and closes around this hinge 29a.

[0074] As shown in Fig. 4, a structure 29 that supports the movable cover 21 is installed inside the bioshield 5. The structure 29 supports the movable cover 21 via hinges 29a. An example of the structure 29 is a columnar structure that stands along the outside of the outer wall 22 of the vacuum vessel 20, but the structure is not limited to the example shown in Fig. 4.

[0075] When the movable cover 21 is opened or closed, the entire movable cover moves integrally around the hinge 29a. This structure makes the opening and closing of the movable cover more efficient than, for example, a structure in which multiple movable covers are arranged above n module assemblies 50A.

[0076] 3, a transfer system 70 is provided above the vacuum vessel 20. The opening and closing of the movable cover 21 may be achieved by this transfer system 70. For example, one or more engaged portions 21d (see FIG. 6B) may be provided on the upper surface of the movable cover 21. The transfer system 70 may hook a hook (engagement portion) provided at the tip of a wire 73a onto the engaged portion 21d, and lift up the portion of the movable cover 21 opposite the structure 29.

[0077] The support structure and opening / closing method of movable cover 21 are not limited to the examples described here. For example, movable cover 21 may be supported without hinge 29a. In this case, movable cover 21 may be movable up and down, for example, by conveyance system 70, while maintaining the entire movable cover 21 in a horizontal position.

[0078] [Connection and release of the movable cover and outer wall] As shown in Fig. 6B, the outer peripheral edge 21a of the movable cover 21 may be airtightly joined to, for example, the upper edge 22a of the outer peripheral wall 22 of the vacuum vessel 20. The outer peripheral edge 21a of the movable cover 21 may be a ring portion that extends radially outward. The upper edge 22a of the outer peripheral wall 22 may also be a ring portion that extends radially outward. These two ring portions (21a and 22a) may be welded together. This ensures the airtightness of the vacuum vessel 20.

[0079] 6B, the vacuum vessel 20 may be provided with a release device 27 that releases the connection between the movable cover 21 and the outer peripheral wall 22. If the movable cover 21 and the outer peripheral wall 22 are welded together, the release device 27 may be, for example, a cutting machine that cuts off the welded portion.

[0080] The release device 27 may be movable along the outer peripheral edge 21a of the movable cover 21. As shown in FIG. 6B , the vacuum vessel 20 may have, for example, a guide 22b extending along the outer peripheral edge 21a of the movable cover 21. This guide 22b may be fixed to the top of the outer peripheral wall 22 and formed around the entire circumference of the vacuum vessel 20. The release device 27 may be movable along this guide 22b over 360 degrees in the circumferential direction Dr of the furnace body M. The release device 27 may move along the guide 22b while releasing the joint between the movable cover 21 and the outer peripheral wall 22, i.e., while cutting the welded portion. By using such a release device 27, the operation of opening the movable cover 21 can be performed efficiently.

[0081] If the end (the outermost part in the radial direction) of the ring portion, which is the outer peripheral edge 21a of the movable cover 21, is welded to the end of the ring portion, which is the upper edge 22a of the outer peripheral wall 22, the release device 27 (cutting machine) cuts off only that end. This makes it possible to separate the movable cover 21 from the outer peripheral wall 22. When re-fixing the movable cover 21 to the outer peripheral wall 22, the remainder of the ring portion, which is the outer peripheral edge 21a of the movable cover 21, may be welded to the remainder of the end of the ring portion, which is the upper edge 22a of the outer peripheral wall 22. This allows the movable cover 21 to be used repeatedly.

[0082] The release device 27 may be configured so that its position can be adjusted in the radial direction of the furnace body M. This allows the position of the release device 27 to be moved closer to the outer peripheral edge 21a of the movable cover 21, for example, when the distance between the guide 22b and the outer peripheral edge 21a increases as a result of repeated opening and closing of the movable cover 21.

[0083] 6A, the vacuum vessel 20 may be provided with a joining device 28 that joins the movable cover 21 and the outer peripheral wall 22. The joining device 28 may be, for example, a welding machine that welds the outer peripheral edge 21a (ring portion) of the movable cover 21 and the upper edge 22a (ring portion) of the outer peripheral wall 22 together.

[0084] Like the release device 27, the joining device 28 may also be movable along the outer peripheral edge 21a of the movable cover 21. For example, the joining device 28 may also be movable 360 ​​degrees in the circumferential direction Dr of the furnace body M along a guide 22b extending along the outer peripheral edge 21a of the movable cover 21. The joining device 28 may move along the guide 22b while joining the movable cover 21 and the outer peripheral wall 22, i.e., while welding them together. By using such a joining device 28, the operation of closing the movable cover 21 can be performed efficiently.

[0085] The joining device 28 may be configured so that its position can be adjusted in the radial direction of the furnace body M. This allows the position of the joining device 28 to be moved closer to the outer peripheral edge 21a of the movable cover 21, for example, when the distance between the guide 22b and the outer peripheral edge 21a increases as a result of repeated opening and closing of the movable cover 21.

[0086] [Other structures of the vacuum vessel] The structure of the vacuum vessel 20 is not limited to the above example. For example, in Fig. 6A etc., only one joining device 28 is shown, but multiple joining devices 28 may be movable along the guide 22b. Similarly, in Fig. 6A etc., multiple release devices 27 may be movable along the guide 22b. This allows the opening and closing operations of the movable cover 21 to be performed more efficiently.

[0087] In yet another example, the ring portion of the outer peripheral edge 21a of the movable cover 21 and the ring portion of the upper edge 22a of the outer peripheral wall 22 may be fastened with a bolt. In this case, a device (robot) that fastens and unfastens the bolt may be used as the release device 27 and the joining device 28. In this case, too, this device may be movable along the guide 22b.

[0088] 5, one movable cover 21 covers the entire circumference of the reactor body M in the circumferential direction Dr of the reactor body M. However, the vacuum vessel 20 may have multiple movable covers that are lined up in the circumferential direction Dr of the reactor body M and connected to each other. Each movable cover may cover the upper sides of two adjacent module assemblies 50A.

[0089] That is, the first movable cover may cover the upper sides of two adjacent module assemblies 50A (first and second module assemblies 50A). The first movable cover may be configured to move as a whole when opened or closed. A second movable cover disposed adjacent to the first movable cover may also cover the upper sides of two adjacent module assemblies 50A (third and fourth module assemblies 50A). The second movable cover may be configured to move as a whole when opened or closed. For example, the vacuum vessel 20 may have two movable covers. In this case, one movable cover may cover half of the n module assemblies 50A, and the other movable cover may cover the remaining half. This structure also makes it possible to more efficiently open and close the movable covers than, for example, a structure in which one movable cover covers only one module assembly 50A.

[0090] When the outer peripheral edge 21a of the movable cover 21 and the upper edge 22a of the outer peripheral wall 22 are released from each other, for example, when the welded portion is cut, dust and scraps are generated. The vacuum vessel 20 may be provided with a device for absorbing such dust and scraps. For example, such an absorbing device may also be movable along the guide 22b. Alternatively, the absorbing device may be suspended by the conveying system 70, and its position may move along the outer peripheral edge 21a of the movable cover 21.

[0091] [Relationship between the piping supplying liquid breeding material and the movable cover] As shown in Figure 6B, multiple connecting pipes 21c are fixed to the movable cover 21. The connecting pipes 21c move integrally with the movable cover 21 when the movable cover 21 is opened or closed. The multiple connecting pipes 21c are respectively located above the n module assemblies 50A (more specifically, above the upper pool 61). Liquid propagation material is supplied to each module assembly 50A through these connecting pipes 21c.

[0092] As described above, the liquid breeding material circulation system 4 has a plurality of supply pipes 4c (see FIG. 6B). The supply pipes 4c extend from the outside to the inside of the bioshield 5 in the radial direction of the reactor body M. The ends of the plurality of supply pipes 4c are connected to a plurality of connecting pipes 21c, respectively.

[0093] The end of the supply pipe 4c may be detachable from the connecting pipe 21c. For example, flanges may be formed on the end of the supply pipe 4c and the end of the connecting pipe 21c, and these two flanges may be fastened together with bolts. In this case, the helical fusion reactor 10 may have a remotely operated robot (not shown) for fastening and loosening the bolts. This remotely operated robot may be controllable from outside the bioshield 5. This remotely operated robot may also be movable in the circumferential direction Dr of the reactor body M, for example, along guides 22b formed along the outer peripheral wall 22 of the vacuum vessel 20.

[0094] 6A, in a plan view of the vacuum vessel 20, the entire connecting pipe 21c is located inside the outer circumferential edge 21a of the movable cover 21. The supply pipe 4c is movable in the radial direction of the furnace body M. More specifically, the end of the supply pipe 4c (the connection portion with the connecting pipe 21c) is movable to the outside of the outer circumferential edge 21a of the movable cover 21. This movement of the supply pipe 4c may be achieved, for example, by a transport system 70, which will be described later.

[0095] [Transportation system] As shown in FIG. 3, the transport system 70 may be, for example, a crane. The transport system 70 has a moving device 73 equipped with a hoisting device for a wire 73a. Each blanket module 51 is hooked onto an engagement portion (hook) provided at the tip of the wire 73a. The transport system 70 also has a first transport mechanism 71 and a second transport mechanism 72, as shown in FIG. 2. The first transport mechanism 71 moves the blanket module 51 above the reactor body M. The second transport mechanism 72 moves the blanket module 51 from a position above the reactor body M to the storage chamber 5a of the blanket module 51 installed in the bioshield 5.

[0096] As shown in Fig. 3, the first transport mechanism 71 has a rotating support rail 71a and a traveling rail 71b. The rotating support rail 71a may be, for example, annular about a vertical center line C1. Both ends of the traveling rail 71b are supported by the rotating support rail 71a, and the traveling rail 71b may be rotatable in the circumferential direction Dr of the furnace body M. The moving device 73 is supported by the traveling rail 71b and is movable in the radial direction of the furnace body M.

[0097] Such a first transfer mechanism 71 allows the blanket module 51 to be moved not only in the vertical direction but also in the circumferential direction Dr of the furnace body M. This makes it easy to move the blanket module 51 to an appropriate position between two adjacent coil upper halves 30a (FIG. 10B). For example, it becomes possible to move the above-mentioned first to third and fifth blanket modules 51_1, 51_2, 51_3, and 51_5 in the circumferential direction Dr of the furnace body M.

[0098] 15A and 16, a plurality of engaged portions 53c are preferably formed on the module upper portion 53 of each blanket module 51. A plurality of winding devices are preferably mounted on the moving device 73. A plurality of engaging portions (hooks) provided at the ends of a plurality of wires 73a extending from the winding devices may be respectively connected to the plurality of engaged portions 53c.

[0099] The number of engaged portions 53c of the module upper portion 53 may be, for example, three. The three engaged portions 53c are preferably spaced apart in the circumferential direction Dr of the reactor body M and in the radial direction of the reactor body M. This makes it possible to control the attitude of each blanket module 51 when moving the blanket module 51. The number of engaged portions 53c is not limited to three.

[0100] For example, it is possible to tilt the blanket module 51 with respect to the vertical center line C1. More specifically, it is possible to tilt the blanket module 51 in the radial direction of the reactor body M, or to tilt the blanket module 51 in the circumferential direction Dr of the reactor body M. This makes it easier to avoid interference between the blanket module 51 and other components.

[0101] The supply pipe 4c of the liquid breeding material circulation system 4 may also be movable by this first transport mechanism 71. For example, an engagement portion may be provided on the supply pipe 4c. The first transport mechanism 71 may then move the position of the supply pipe 4c so that the end of the supply pipe 4c (the connection portion with the connecting pipe 21c) moves to the outside of the outer circumferential edge 21a of the movable cover 21. In this case, the supply pipe 4c may have an expansion joint along its length that allows its length to be adjusted.

[0102] As shown in Fig. 2, the second transport mechanism 72 may have a running rail 72a. The running rail 72a extends from a position above the vacuum vessel 20 to the storage chamber 5a. A running rail 71b (see Fig. 3), which is rotatable along the rotation support rail 71a, can be aligned in a straight line with the running rail 72a. In this state, the moving device 73 can move between the running rail 71b and the running rail 72a.

[0103] This allows the blanket module 51, which has been lifted up from the reactor main body M by the first transfer mechanism 71, to be transferred to the storage chamber 5a. Conversely, the blanket module 51 stored in the storage chamber 5a can be moved from the storage chamber 5a to the reactor main body M.

[0104] [Maintenance work] The maintenance work for the blanket module 51 will be described below.

[0105] First, a remote-controlled robot is used to disconnect the multiple supply pipes 4c from the connecting pipes 21c of the movable cover 21 (S101). Then, the first transfer mechanism 71 is used to move the supply pipes 4c in the radial direction of the furnace body M until their ends are moved to the outside of the outer circumferential edge 21a of the movable cover 21 (S102).

[0106] Next, the release device 27 is driven to cut the weld between the movable cover 21 and the outer peripheral wall 22 (S103). At this time, the release device 27 is controlled to move around the outer peripheral edge 21a of the movable cover 21 once. If the vacuum vessel 20 has multiple release devices 27, they may be driven simultaneously. Then, the movable cover 21 is opened (S104). The opening operation of the movable cover 21 may be performed by, for example, the first transfer mechanism 71 of the transfer system 70.

[0107] Next, the upper pool 61 attached to the module assembly 50A to be maintained is separated from the module assembly 50A using the first transport mechanism 71 (S105). This upper pool 61 may be moved to the storage chamber 5a using, for example, the first transport mechanism 71 and the second transport mechanism 72.

[0108] Next, the nine blanket modules 51 constituting the module assembly 50A to be maintained are sequentially separated from the reactor body M (S106). The separated blanket modules 51 are moved to the storage chamber 5a using the first transport mechanism 71 and the second transport mechanism 72 (S107).

[0109] 13A, the blanket modules 51 may be numbered 1 to 9. The numbers assigned to the blanket modules 51 correspond to the subscripts of the symbols assigned to the blanket modules 51. In S106, of the nine blanket modules 51, the blanket modules 51 are separated in order, starting with the blanket module 51 arranged closer to the center in the circumferential direction Dr of the reactor body M. For example, the nine blanket modules 51 may be separated from the reactor body M in the order of the ninth blanket module 51_9, the eighth blanket module 51_8, the seventh blanket module 51_7, and so on.

[0110] After the blanket modules 51 closer to the center are separated, the blanket modules 51 arranged on the outer sides in the circumferential direction Dr of the reactor body M may be separated. For example, the fifth blanket module 51_5, the fourth blanket module 51_4, the third blanket module 51_3, the second blanket module 51_2, and the first blanket module 51_1, each having a module lower part 52 located below the coil upper half part 30a, are separated in this order.

[0111] The operation of inserting the blanket modules 51 into the reactor body M may be performed in the reverse order of the order shown in Fig. 18. That is, the blanket modules 51 are inserted between two adjacent coil upper half portions 30a in order starting from the blanket module 51 arranged on the outer side in the circumferential direction Dr of the reactor body M. That is, the first blanket module 51_1, the second blanket module 51_2, the third blanket module 51_3, the fourth blanket module 51_4, and the fifth blanket module 51_5, each having a module lower portion 52 located below the coil upper half portion 30a, are inserted in this order.

[0112] Thereafter, the blanket modules 51 closer to the center are inserted between the coil upper half portions 30a. That is, the sixth blanket module 51_6, the seventh blanket module 51_7, the eighth blanket module 51_8, and the ninth blanket module 51_9 are inserted between the coil upper half portions 30a in this order.

[0113] The inner shielding wall 45 of the cryostat 40 may have a guide surface that guides the module lower portion 52 of the blanket module 51. The guide surface may be an inclined surface that is inclined so that the module lower portion 52 of the blanket module 51 moves in an appropriate direction.

[0114] [Summary 1] As described above, the blanket 50 has a plurality of module assemblies 50A arranged in the circumferential direction Dr around the vertical centerline C1 of the helical coil 30, and each of the plurality of module assemblies 50A includes a plurality of blanket modules 51. Each blanket module 51 is movable upward through a gap A formed in the helical coil 30. The vacuum vessel 20 has an openable and closable movable cover 21 that covers the helical coil 30 and the upper sides of the plurality of module assemblies 50A. The movable cover 21 is configured so that the entire movable cover 21 moves integrally when opened or closed. This structure improves the efficiency of opening and closing the movable cover 21. Therefore, blanket maintenance and replacement work can be performed more efficiently than in a structure in which one movable cover is provided per module assembly.

[0115] As described above, the helical coil 30 includes the first coil upper half 30a, the second coil upper half 30a, and the third coil upper half 30a, which are aligned in the circumferential direction Dr about the vertical centerline C1 of the helical coil 30 and located above a horizontal plane P1 passing through the center of the helical coil 30. The multiple module assemblies 50A include a first module assembly 50A located between the first coil upper half 30a and the second coil upper half 30a in a plan view of the helical coil 30, and a second module assembly 50A located between the second coil upper half 30a and the third coil upper half 30a in a plan view of the helical coil 30. The vacuum vessel 20 has an openable and closable movable cover 21 covering the top sides of the first module assembly 50A and the second module assembly 50A. This structure also improves the efficiency of opening and closing the movable cover 21 compared to a structure in which one movable cover is provided per module assembly. In this structure, the vacuum vessel 20 may have a plurality of movable covers 21, which may be combined to cover the entire furnace body M. In this case, two adjacent movable covers may be capable of being opened and closed independently.

[0116] The maintenance method described above includes the steps of moving the release device 27 along the outer peripheral edge 21a of the movable cover 21 to release the connection between the outer peripheral edge 21a of the movable cover 21 and another part (the outer peripheral wall 22) of the vacuum vessel 20, opening the movable cover 21, and using the transport system 70 to lift the blanket modules 51 that make up the blanket 50 from the gaps formed in the helical coil 30. In this method, the release device 27 that can move along the outer peripheral edge 21a of the movable cover 21 is used, which makes it possible to efficiently open the movable cover 21 and, as a result, to efficiently perform blanket maintenance and replacement work.

[0117] [Summary 2] As described above, the blanket 50 includes n module assemblies 50A that make one revolution around the vertical centerline C1 of the helical coil 30. Each of the n module assemblies 50A includes m blanket modules 51. The lower module parts 52 of the m blanket modules 51 in each module assembly 50A are combined with each other to form a plasma-facing wall 50W having a length corresponding to 360 / n degrees around the centerline C1. All of the m blanket modules 51 in each module assembly 50A are movable upward through gaps formed in the helical coil 30 (gaps A between adjacent coil upper halves 30a). With this structure, the upwardly movable blanket modules 51 alone can form an annular plasma-facing wall 50W centered on the vertical centerline C1.

[0118] The helical coil 30 includes a first coil upper half 30a and a second coil upper half 30a that are adjacent to each other in the circumferential direction Dr around a center line C1 that is aligned vertically with the helical coil 30 and are located above a horizontal plane P1 that passes through the center of the helical coil 30. The blanket 50 includes multiple module assemblies 50A aligned in the circumferential direction Dr of the reactor body M, and each of the multiple module assemblies 50A includes multiple blanket modules 51. The first module assembly 50A is disposed between the first coil upper half 30a and the second coil upper half 30a in a plan view of the helical coil 30 and is movable upward between them. The multiple blanket modules 51 that make up the first module assembly 50A include first and second blanket modules 51_1 and 51_2 at one end of the reactor body M in the circumferential direction Dr, and form part of the plasma-facing wall 50W. Module lower portions 52 of the first and second blanket modules 51_1 and 51_2 are located below the first coil upper half portion 30a. The blanket modules 51 also have third and fifth blanket modules 51_3 and 51_5 at opposite ends, which form another part of the plasma-facing wall 50W. Module lower portions 52 of the blanket modules 51_3 and 51_5 are located below the second coil upper half portion 30a.

[0119] According to this structure, the number of blanket modules that need to be slid in the radial direction of the reactor body M during maintenance and replacement work of the blanket modules 51 can be reduced or eliminated.

[0120] In addition, in this structure, the module lower portions 52 of the first and second blanket modules 51_1 and 51_2 protrude to one side in the circumferential direction Dr of the reactor body M beyond the flow path portion 54. The module lower portions 52 of the third and fifth blanket modules 51_3 and 51_5 protrude to the opposite side in the circumferential direction Dr of the reactor body M beyond the flow path portion 54. This structure can reduce the gap between two adjacent module assemblies 50A.

[0121] The helical coil 30 includes a first coil upper half 30a and a second coil upper half 30a that are adjacent to each other in the circumferential direction around a centerline C1 that is aligned vertically with the helical coil 30 and are located above a horizontal plane P1 that passes through the center of the helical coil 30. The blanket 50 includes multiple module assemblies 50A arranged in the circumferential direction, each including multiple blanket modules 51. Each of the multiple module assemblies 50A is configured so that liquid propagation material flows from the top to the bottom of the module assembly 50A. One of the multiple module assemblies 50A, the first module assembly 50A, is disposed between the first coil upper half 30a and the second coil upper half 30a. The multiple blanket modules 51 of the first module assembly 50A are combined with each other to form a discharge opening 55a at their lower ends. The lower pool 62 is located below the discharge opening 55a.

[0122] This structure can smooth the flow of liquid breeding material from the surface 52g of the module lower part 52 to the lower pool 62. In addition, helium ash and the like from the divertor plasma formed near the discharge opening 55a of the module lower part 52 can be efficiently discharged to the lower pool 62 together with the liquid breeding material.

[0123] The helical coil 30 also includes two coil lower halves 30b that are located below the horizontal plane P1 and adjacent to each other in the circumferential direction. The lower pool 62 is disposed between the two coil lower halves 30b. This allows the distance between the module lower part 52 and the lower pool 62 to be reduced.

[0124] It should be noted that the helical fusion reactor, the vacuum vessel of the helical fusion reactor, and the blanket replacement method proposed in this disclosure are not limited to the examples described with reference to FIGS.

[0125] In the example described above, the lower part of the blanket module 51 (module lower part 52) ​​is disposed inside the helical coil 30, and the upper part (module upper part 53) is supported on the upper side of the upper wall 41 of the cryostat 40. However, the arrangement of the blanket module 51 is not limited to this, and for example, the entire blanket module 51 may be disposed inside the helical coil 30. [Explanation of symbols]

[0126] 2: plasma heating device, 3: fuel circulation system, 3a: injector, 4: liquid breeder circulation system, 4a: heat exchanger, 4b: tritium recovery device, 4c: supply pipe, 5: bioshield, 5a: storage chamber, 6: vacuum pump, 10: helical fusion reactor, 21: movable cover, 21a: outer periphery, 21c: connecting pipe, 21d: engaged part, 22: outer periphery wall, 22a: upper edge, 22b: guide, 27: release device, 28: joining device, 29: structure, 29a: hinge, 30: helical coil, 30a: upper half of coil, 30b: lower half of coil, 31: coil support, 31A, 31B: coil housing, 31a to 31d: hollow tube, 32A, 32B, 33A, 33B: vertical magnetic field coil, 40: cryostat, 41: upper wall, 41a: opening, 42: inner Wall, 43: outer wall, 44: bottom wall, 44a: opening, 45: inner shielding wall, 49: feed screw, 50: breeding blanket, 50A: module assembly, 50W: plasma-facing wall, 51, 51_1 to 51_9: blanket module, 52: lower module part, 52a, 52b, 52c, 52e: side, 52g: surface, 53: upper module part, 53a: supply port, 53c: engaged part , 53d: guided portion, 53e: screw hole, 54: flow path portion, 55a: discharge opening, 59: test module, 61: upper pool, 61a: connecting pipe, 62: lower pool, 62a: discharge pipe, 70: conveying system, 71: first conveying mechanism, 71a: rotating support rail, 71b: running rail, 72: second conveying mechanism, 72a: running rail, 73: moving device, 73a: wire, A: gap.

Claims

1. A helical coil; a blanket at least partially disposed inside the helical coil; a vacuum vessel containing the helical coil and the blanket; and the blanket has a plurality of module assemblies arranged in a circumferential direction around a centerline along a vertical direction of the helical coil, each of the plurality of module assemblies including a plurality of blanket modules; Each blanket module is movable upward through a gap formed in the helical coil; the vacuum vessel has an openable and closable movable cover covering the helical coil and the upper sides of the plurality of module assemblies, The movable cover is configured so that the entire movable cover moves integrally when the movable cover is opened or closed. Helical fusion reactor.

2. A helical coil; a blanket at least partially disposed inside the helical coil; a vacuum vessel containing the helical coil and the blanket; and the helical coil includes a first coil upper half, a second coil upper half, and a third coil upper half that are aligned in a circumferential direction around a center line of the helical coil along a vertical direction and are positioned above a horizontal plane that passes through a center of the helical coil, the blanket has a plurality of module assemblies arranged in the circumferential direction, each of the plurality of module assemblies including a plurality of blanket modules; the plurality of module assemblies include a first module assembly located between the first coil upper half and the second coil upper half in a plan view of the helical coil, and a second module assembly located between the second coil upper half and the third coil upper half in a plan view of the helical coil, the vacuum vessel has an openable and closable movable cover covering at least the first module assembly and the second module assembly from above; The movable cover is configured so that the entire movable cover moves integrally when the movable cover is opened or closed. Helical fusion reactor.

3. a cryostat housing the helical coil; the cryostat has an upper wall covering an upper side of the helical coil; a plurality of openings are formed in the upper wall, and positions of the plurality of openings correspond to positions of the plurality of module assemblies, respectively; The plurality of module assemblies are movable upwardly through the plurality of openings.

3. A helical-type nuclear fusion reactor according to claim 1 or 2.

4. The portion that moves integrally when the movable cover is opened and closed covers the plurality of module assemblies over the entire circumference around the center line that is aligned in the vertical direction of the helical coil.

3. A helical-type nuclear fusion reactor according to claim 1 or 2.

5. The movable cover is supported via a hinge and can be opened and closed around the hinge.

3. A helical-type nuclear fusion reactor according to claim 1 or 2.

6. The outer periphery of the movable cover is joined to another part of the vacuum vessel, The vacuum chamber further includes a release device that is movable along the outer periphery of the movable cover and releases the connection between the outer periphery of the movable cover and the other portion of the vacuum chamber.

3. A helical-type nuclear fusion reactor according to claim 1 or 2.

7. The release device is movable substantially around the vertical centerline of the helical coil.

3. A helical-type nuclear fusion reactor according to claim 1 or 2.

8. the vacuum vessel has a guide disposed along the outer periphery of the movable cover; The release device is movable along the guide 8. A helical-type nuclear fusion reactor according to claim 7.

9. The outer periphery of the movable cover is joined to another part of the vacuum vessel, The release device is a device for cutting the welded portion.

7. A helical-type nuclear fusion reactor according to claim 6.

10. a storage compartment for the blanket module; a transport system that moves each blanket module above the helical coil and moves each blanket module from a position above the helical coil to the storage chamber; 3. The helical-type nuclear fusion reactor according to claim 1 or 2, further comprising:

11. The transport system is configured to move the position of each blanket module in the circumferential direction.

11. The helical type nuclear fusion reactor according to claim 10.

12. The transport system is configured to tilt each blanket module relative to the vertical centerline of the helical coil.

11. The helical type nuclear fusion reactor according to claim 10.

13. Each of the plurality of module assemblies is configured so that liquid propagation material flows through the interior of each module assembly from its upper side to its lower side; The movable cover is connected to a pipe for supplying the liquid propagation material to the upper side of the plurality of module assemblies.

3. A helical-type nuclear fusion reactor according to claim 1 or 2.

14. The piping includes a connecting pipe fixed to the movable cover and moving integrally with the movable cover when the movable cover is opened or closed, and a supply pipe connected to the connecting pipe and separable from the connecting pipe.

14. The helical type nuclear fusion reactor according to claim 13.

15. an end of the connecting pipe is located inside the outer periphery of the movable cover; The supply pipe is separated from the connecting pipe and is movable to the outside of the outer periphery of the movable cover.

15. The helical fusion reactor according to claim 14.

16. At least a portion of the blanket is disposed inside the helical coil; In a helical fusion reactor, the blanket has a plurality of module assemblies arranged in a circumferential direction around a center line along a vertical direction of the helical coil, each of the plurality of module assemblies includes a plurality of blanket modules, and each blanket module is movable upward through a gap formed in the helical coil, a vacuum vessel for accommodating the helical coil and the blanket, the vacuum vessel has an openable and closable movable cover covering the helical coil and the upper sides of the plurality of module assemblies, The movable cover is configured so that the entire movable cover moves integrally when the movable cover is opened or closed. The vacuum vessel of a helical fusion reactor.

17. At least a portion of the blanket is disposed inside the helical coil; the helical coil includes a first coil upper half, a second coil upper half, and a third coil upper half that are arranged in a circumferential direction around a center line of the helical coil along a vertical direction and are located above a horizontal plane that passes through a center of the helical coil, a helical fusion reactor, wherein the blanket has a plurality of module assemblies lined up in the circumferential direction, each of the plurality of module assemblies including a plurality of blanket modules, and the plurality of module assemblies include a first module assembly located between the first coil upper half and the second coil upper half in a plan view of the helical coil, and a second module assembly located between the second coil upper half and the third coil upper half in a plan view of the helical coil; a vacuum vessel for accommodating the helical coil and the blanket, the vacuum vessel has an openable and closable movable cover covering at least the first module assembly and the second module assembly from above; The movable cover is configured so that the entire movable cover moves integrally when the movable cover is opened or closed. The vacuum vessel of a helical fusion reactor.

18. At least a portion of the blanket is disposed inside the helical coil; A maintenance method for a helical-type nuclear fusion reactor, wherein the helical coil and the blanket are housed in a vacuum vessel, the vacuum vessel has a movable cover covering an upper side of the helical coil, and an outer periphery of the movable cover is joined to another part of the vacuum vessel, comprising: a step of moving a release device along the outer circumferential edge of the movable cover to release the connection between the outer circumferential edge of the movable cover and the other portion of the vacuum vessel; opening the movable cover; lifting a blanket module constituting the blanket from a gap formed in the helical coil using a transport system; A maintenance method for a helical fusion reactor, including:

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