Nuclear fusion reactor system

Abstract

The present invention simplifies a system for fuel circulation. A nuclear fusion reactor system (10) comprises: a vacuum container (20); an exhaust device (31) that is connected to the vacuum container (20) and discharges gas inside the vacuum container (20); a blanket (50) that is disposed inside the vacuum container (20) and surrounds a space in which plasma is formed; a tritium breeding material that is supplied to the blanket (50); and a fuel storage device (35) that is installed outside the vacuum container (20). The tritium breeding material is a liquid metal containing lithium and tin, and releases, from the tritium breeding material in the vacuum container (20), tritium generated by the tritium breeding material. The exhaust device (31) discharges the tritium released from the tritium breeding material to outside the vacuum container (20) toward the fuel storage device (35).

Description

Fusion Reactor System

[0001] The present disclosure relates to a technique for recovering tritium, which is a fuel for a nuclear fusion reactor system.

[0002] In a fusion reactor, a tritium breeder material is provided in the blanket to generate tritium, which serves as fuel. A material containing lithium is used as the tritium breeder material. Tritium generated by the reaction between lithium and neutrons is collected together with the carrier gas flowing inside the blanket, passes through a fuel circulation system installed outside the vacuum vessel, and is reused as fuel. Liquid breeder materials have also been proposed as tritium breeder materials. For example, Non-Patent Documents 1 and 2 listed below propose helical-type fusion reactors that use liquid metal containing lithium as a tritium breeder material.

[0003] 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)J. Miyazawa, T. Goto, "Development of steady-state fusion reactor by Helical Fusion", Physics of Plasmas, AIP Publishing, 22nd May 2023, 30, 050601 (2023)

[0004] Simplifying the fuel circulation system for tritium recovery is extremely important for the practical application of nuclear fusion reactors. Previously proposed fuel circulation systems required a dedicated mechanism and structure for tritium recovery, or used a DT separator to separate and store tritium from the other fuel, deuterium, making them less than optimal from a practical standpoint.

[0005] The nuclear fusion reactor system proposed in this disclosure includes a vacuum vessel, an exhaust device connected to the vacuum vessel and exhausting gas within the vacuum vessel, a blanket disposed within the vacuum vessel and surrounding a space in which plasma is generated, a tritium breeder material supplied to the blanket, and a fuel storage device installed outside the vacuum vessel. The tritium breeder material is a liquid metal containing lithium and tin, and releases tritium produced by the tritium breeder material from the tritium breeder material within the vacuum vessel. The exhaust device discharges the tritium released from the tritium breeder material to the outside of the vacuum vessel, toward the fuel storage device.

[0006] This nuclear fusion reactor system can simplify the fuel circulation system.

[0007] 9A . A block diagram showing the fusion reactor system proposed in the present disclosure. A schematic diagram showing the inside of a vacuum vessel. A perspective view showing a fusion reactor system. An exploded perspective view of the fusion reactor main body and the vacuum vessel. A perspective view showing the inside of the vacuum vessel. A perspective view of a reactor module. A perspective view of a reactor module. A perspective view of a coil. A plan view of a coil. An exploded perspective view of a reactor module. An exploded perspective view of a blanket module assembly and upper and lower pools. A plan view of two blanket module assemblies. A perspective view showing the lower part of a blanket module assembly. A cross-sectional view of the reactor module shown along line Xa-Xa in FIG. 9A. A cross-sectional view of the reactor module shown along line Xb-Xb in FIG. 9A. A cross-sectional view of the reactor module shown along line Xc-Xc in FIG. 9A. An exploded view of a blanket module assembly.

[0008] The fusion reactor system proposed in this disclosure will be described below. In this specification, as an example of a fusion reactor system, a fusion reactor system 10 shown in FIG. 1 etc. will be described. In the following description, tritium, which is the fuel for the fusion reactor, may be represented as "T" and deuterium as "D."

[0009] 1, the fusion reactor system 10 has a vacuum vessel 20 that houses a fusion reactor main body M. The reactor main body M has a coil 70 (see FIG. 7A) for confining plasma, a blanket 50 (see FIG. 8B) that surrounds the space where plasma is generated, a cryostat 40 (see FIG. 8A), and the like.

[0010] 1, the fusion reactor system 10 also has a fuel circulation system 30. The fuel circulation system 30 is a system that recovers tritium and deuterium, which serve as fuel, from the vacuum vessel 20 and supplies them back to the fusion reactor main body M.

[0011] [Tritium Breeder Material] In the fusion reactor system 10, a liquid metal containing lithium and tin is used as a tritium breeder material. The liquid tritium breeder material is supplied to the blanket 50 from the outside of the vacuum vessel 20 by the breeder circulation system 4 (see FIG. 5 ). As will be described later, the interior of the blanket 50 is formed so that the tritium breeder material flows from the top to the bottom of the blanket 50. The tritium breeder material is supplied to the top of the blanket 50 by the breeder circulation system 4, and flows downward inside the blanket 50.

[0012] 2 is a schematic diagram showing the inside of the vacuum vessel 20. As the tritium breeder material flows downward through the blanket 50, neutrons (n) generated by the plasma react with lithium (Li) contained in the tritium breeder material, and tritium (T) is produced by this reaction.

[0013] As will be described later, the blanket 50 has a plasma containment section 50W that surrounds the space where plasma is generated. A passage through which tritium breeder material can pass can be formed between the inside and outside of the blanket 50 (plasma containment section 50W). The plasma containment section 50W is formed, for example, from a porous material and is formed so that the tritium breeder material leaks from the surface of the plasma containment section 50W (the surface facing the plasma). The multiple pores in the porous material can be passages between the inside and outside of the blanket 50 (blanket containment section 50W). As shown in FIG. 2 , the tritium breeder material may form a film on the surface of the plasma containment section 50W. This film can function as a first wall that comes into direct contact with the plasma, thereby protecting the blanket 50. Note that the plasma containment section 50W does not necessarily have to be formed so that the tritium breeder material leaks from the surface of the plasma containment section 50W. For example, the tritium breeder material may be configured to flow vertically on the surface of the plasma containment section 50W.

[0014] As shown in FIG. 2 , the tritium breeder material that has passed through the blanket 50 accumulates below the blanket 50. The vacuum vessel 20 contains a lower pool 62 (see FIG. 8B ) that is disposed below the blanket 50. The tritium breeder material that has passed through the blanket 50 accumulates in this lower pool 62. As described above, the tritium breeder material contains tin. The hydrogen solubility of tin is extremely low. In other words, the permeability of tritium through tin is high. Therefore, tritium does not dissolve in the tritium breeder material, but is released (evaporated) within the vacuum vessel 20 from the free surface of the tritium breeder material accumulated in the lower pool 62.

[0015] A part of the tritium released from the tritium breeder material is ionized in the space where the plasma is formed and can be used as fuel. The rest of the tritium released from the tritium breeder material is discharged to the outside of the vacuum vessel 20 by the exhaust device 31 together with helium and unburned fuel.

[0016] The tritium breeding material (liquid metal) may contain a neutron multiplier. For example, lead can be used as the neutron multiplier. This makes it possible to multiply neutrons before they react with lithium, thereby improving the tritium breeding ratio.

[0017] For example, the lithium content in the tritium breeder material may be 15% or more and 60% or less, and the tin content in the tritium breeder material may be 40% or more and 85% or less. In this case, the tritium breeder material may contain 0% or more lead as the balance. More preferably, the lithium content in the tritium breeder material may be 15% or more and 50% or less, and the tin content in the tritium breeder material may be 50% or more and 85% or less. In this case, the tritium breeder material may contain 0% or more lead as the balance. Even more preferably, the lithium content in the tritium breeder material may be 15% or more and 35% or less, and the tin content in the tritium breeder material may be 65% or more and 85% or less. In this case, the tritium breeder material may contain 0% or more lead as the balance. The tritium breeder material may be, for example, a liquid metal containing 25% lithium, 6.0% lead, and 69% tin. The tin content in the tritium breeder material may be 5% or more and 85% or less. The tin content in the tritium breeder material may be 30% or more and 85% or less. (In this paragraph and the next paragraph, the composition of each element is expressed in mole percentage (mol%).)

[0018] As another example of the composition, the lithium content may be 10% or more and 55% or less, the lead content may be 5.0% or more and 40% or less, and the remainder may be tin. Note that the composition of the tritium breeder material is not limited to the example described here, as long as the composition allows the necessary tritium to be released from the tritium breeder material.

[0019] 1 , the fuel circulation system 30 has an exhaust device 31 connected to the vacuum vessel 20. The exhaust device 31 exhausts gas inside the vacuum vessel 20 to the outside. Specifically, the exhaust device 31 exhausts, from the vacuum vessel 20, helium generated by the nuclear fusion reaction, unburned tritium and deuterium, and also tritium generated from the tritium breeder material.

[0020] The exhaust device 31 includes, for example, a plurality of cryopumps. The cryopumps exhaust fuel gas (tritium and deuterium) to the outside of the vacuum vessel 20 toward the fuel storage device 35. As shown in Fig. 5, the exhaust device 31 is connected to, for example, the center of the bottom wall 23 of the vacuum vessel 20. The connection position of the exhaust device 31 is not limited thereto, and the exhaust device 31 may be connected to, for example, the outer periphery of the bottom wall 23, the outer periphery wall 22 (see Fig. 4), the upper cover 21 (see Fig. 4), or the like.

[0021] In a cryopump, gas molecules are condensed on the cryopanels, and then the temperature of the cryopanels is raised to vaporize the gas molecules and regenerate the cryopanels. The cryopanels of one of the cryopumps are cooled, and while that cryopump is operating (pumping air), the temperature of the cryopanels of another cryopump is raised to regenerate that cryopanel. This allows for continuous operation of multiple cryopanels.

[0022] Inside the vacuum vessel 20, impurity gases are generated from the structure of the nuclear fusion reactor main body M and the inner wall of the vacuum vessel 20. The impurity gases include carbon compounds (CO ２ Ya, CH ４ etc.), oxidized compounds (O ２ ), nitride compounds (N ２ , NO, etc.), H ２ The exhaust device 31 also exhausts such impurity gases from the vacuum chamber 20. The exhaust device 31 may further include a roughing pump or a turbomolecular pump, both of which are not shown.

[0023] 1, the fuel circulation system 30 has a fuel refinery device 33 disposed between the fuel storage device 35 and the exhaust device 31. The gas discharged from the exhaust device 31 is sent to the fuel refinery device 33. The gas discharged from the exhaust device 31 may be sent to the fuel refinery device 33 via a compressor 32. This allows the fuel refinery device 33 to operate efficiently when the pressure of the gas immediately after being discharged from the exhaust device 31 is lower than the gas pressure suitable for operating the fuel refinery device 33.

[0024] The fuel refinery device 33 refines a gas (D ２ , D.T., T. ２ Specifically, the fuel refining device 33 separates helium and the above-mentioned impurity gases from the gas discharged from the exhaust device 31, and separates the gas (D ２ , D.T., T. ２ ) is purified.

[0025] The fuel refinery 33 may be one or more of a palladium permeable membrane, a high-temperature metal head, a cold trap, and a molecular sieve. The palladium diffuser contains palladium, a material with a higher hydrogen permeability coefficient than other metals, and selectively allows only hydrogen isotopes to permeate. The cold trap is a trap cooled by liquid helium to remove impurity gases. The molecular sieve is made of, for example, synthetic zeolite, and is used to separate the fuel gas (D ２ , D.T., T. ２ ) only.

[0026] 1, the fuel circulation system 30 has a fuel storage device 35. The fuel gas (D ２ , D.T., T. ２ ) is sent to the fuel storage device 35 and stored therein. ２ , D.T., T. ２ ) is stored in the fuel storage device 35 without being separated.

[0027] In conventional fusion reactor systems, deuterium and tritium are separated from each other and stored by passing through a hydrogen isotope separator (DT separator) that performs cryogenic distillation, thermal diffusion, or the like. In the fusion reactor system 10 proposed in this disclosure, deuterium and tritium are stored in a mixed state without passing through such an isotope separator (DT separator). By not using such an isotope separator, the fusion reactor system 10 can be simplified.

[0028] The fuel refining device 33 described above is a device for refining fuel gas (D ２ , D.T., T. ２ ) and hydrogen (H２ In this case, the fuel circulation system 30 can be simplified because the process of separating tritium and deuterium becomes unnecessary. In addition, the fuel (D ２ , D.T., T. ２ ) ratio can be increased.

[0029] In addition, deuterium, which is a type of fuel, may be added to the fuel storage device 35 from an external device (for example, an auxiliary fuel storage device 38 described later) in order to reduce the ratio of protons to the fuel. ２ , DT, and T ２ Deuterium may be added to the fuel storage device 35 so that the ratio of hydrogen to the total fuel (the sum of hydrogen and hydrogen) is equal to or less than a predetermined value (for example, 10%). In this case, the ratio of fuel and / or hydrogen stored in the fuel storage device 35 may be measured, and deuterium may be supplied to the fuel storage device 35 based on the measurement result. Here, the predetermined value is, for example, 10%, more preferably 5%, and even more preferably 1%.

[0030] The addition of deuterium to reduce the ratio of protons may be performed in the fuel supply device 36 (described later) rather than in the fuel storage device 35. That is, the ratio of protons to the fuel supplied to the plasma from the fuel supply device 36 may be measured, and deuterium may be added to the fuel supply device 36 based on the measurement result. In this way, the ratio of the fuel (D ２ , DT, and T ２ The ratio of hydrogen to hydrogen (total of hydrogen and hydrogen) can be set to a predetermined value or less.

[0031] The fuel storage device 35 is, for example, a high-pressure gas tank. In this case, the gas (D ２ , D.T., T. ２ ) may be sent to a fuel storage device 35 via a compressor 34 .

[0032] Note that deuterium and tritium may be stored as hydrides of metals having hydrogen storage capacity (e.g., uranium, zirconium cobalt, etc.) in the fuel storage device 35. As yet another example, deuterium and tritium may be stored as liquid hydrogen in the fuel storage device 35.

[0033] [Fuel Supply Device] As shown in Fig. 1, the fuel circulation system 30 has a fuel supply device 36. Fuel (tritium and deuterium) stored in a fuel storage device 35 is sent to the fuel supply device 36. The fuel supply device 36 is, for example, a pellet injection device, which cools and solidifies a fuel mixture of tritium and deuterium into pellets and injects them into plasma. As shown in Fig. 3, the fuel supply device 36 may be arranged to surround the outside of the vacuum vessel 20.

[0034] The fuel supply device 36 (pellet injection device) has, for example, the following structure and is operated as follows: One end of the fuel supply device 36 is connected to the vacuum vessel 20, and has a pipe through which a fuel mixture of tritium and deuterium gas flows. A portion of the pipe is cooled. When the portion of the pipe is cooled, the mixed gas solidifies in the cooled section, forming pellets that clog the pipe. Thereafter, the supply of fuel gas to the pipe is stopped, and the gas inside the pipe is evacuated, after which high-pressure gas (e.g., helium gas) is applied to the pipe. This causes pellets to be ejected from the pipe toward the plasma.

[0035] Such a pellet injection device generates high-pressure helium gas and unsolidified fuel gas. Therefore, as shown in Fig. 1, the fuel circulation system 30 may have an exhaust device 37 for exhausting these gases. The gas sucked from the pellet injection device by the exhaust device 37 may be sent to a fuel storage device 35 via, for example, a compressor 32 and a fuel purification device 33.

[0036] [Auxiliary Fuel Storage Device] When the fusion reactor system 10 starts operating (immediately after the construction of the fusion reactor system 10), for example, only deuterium is supplied as fuel, and a DD reaction occurs as the fusion reaction. Tritium is generated by the reaction between neutrons generated in the fusion reaction and lithium contained in the tritium breeder material. Therefore, even if tritium is not present in the fuel storage device 35 at the start of operation, it will gradually accumulate in the fuel storage device 35 as the system continues to operate. As operation continues, the proportion of tritium in the fuel storage device 35 (the ratio to deuterium) will gradually increase.

[0037] An auxiliary fuel storage device 38 may be connected to the fuel storage device 35. The auxiliary fuel storage device 38 may store deuterium in advance. The auxiliary fuel storage device 38 may store substantially only deuterium, or may store deuterium with a sufficiently high ratio of deuterium to other components. The fuel (D ２ , D.T., T. ２ ) exceeds a threshold value (e.g., 50%), deuterium from the auxiliary fuel storage device 38 may be added to the fuel storage device 35. This allows the ratio of tritium to deuterium in the fuel supplied from the fuel storage device 35 to the fuel supply device 36 to be maintained at an appropriate level.

[0038] To enable such operation, a mass spectrometer may be connected to the fuel storage device 35. Based on the output from such a mass spectrometer, deuterium from the auxiliary fuel storage device 38 may be added to the fuel storage device 35 so that the ratio of tritium in the fuel stored in the fuel storage device 35 reaches a target value.

[0039] The auxiliary fuel storage device 38 may be connected to the fuel supply device 36. The fuel (D ２ , D.T., T. ２ If the ratio of tritium in the fuel supply 36 exceeds a threshold value (e.g., 50%), deuterium from the auxiliary fuel storage device 38 may be added to the fuel supply 36. This allows the ratio of tritium to deuterium in the fuel supplied to the plasma from the fuel supply 36 to be maintained at an appropriate level.

[0040] [Nuclear Fusion Reactor Main Body] The nuclear fusion reactor main body M will be described in detail below. As described above, the reactor main body M is housed in the vacuum vessel 20. As shown in Fig. 4, the vacuum vessel 20 has a cylindrical outer peripheral wall 22 and an upper cover 21 connected to the upper side of the outer peripheral wall 22. The upper cover 21 is openable and closable to allow maintenance work on the blanket 50 and the like.

[0041] As shown in Figures 6A and 6B, the nuclear fusion reactor main body M has a coil 70 (see Figure 7A), a cryostat 40, and a blanket 50. The reactor main body M is composed of n reactor modules (m) arranged in the circumferential direction. In the example proposed in the present disclosure, the reactor main body M has 10 reactor modules (m). One reactor module (m) constitutes a portion corresponding to 360 / n degrees of the reactor main body M. The n reactor modules (m) may have substantially the same structure. Figures 7A and 7B show this one module (m).

[0042] [Coil] As shown in FIG. 7A, the coil 70 has a coil support 71. The fusion reactor system 10 proposed in this disclosure is a helical type, and the coil support 71 is double-helix shaped. That is, the coil support 71 has two coil housings 71A and 71B formed along a torus surface centered on the vertical center line C1 of the reactor body M. Each of the coil housings 71A and 71B has, for example, a plurality of hollow tubes 71a to 71d formed therein. Each of these hollow tubes 71a to 71d houses a superconducting wire (not shown) and a cooling tube (not shown) that serves as a flow path for a coolant. Liquid helium, for example, can be used as the coolant.

[0043] The structure of the coil housings 71A and 71B is not limited to the example described here. For example, the coil 70 may not be equipped with cooling pipes. In this case, the hollow tubes 71a to 71d may be filled with a coolant. In addition, in the example shown in FIG. 7A, four hollow tubes 71a to 71d are formed in each of the coil housings 71A and 71B, but the number may be less than or more than three. Furthermore, the fusion reactor system 10 does not have to be a helical type. For example, the fusion reactor system 10 may be a tokamak type.

[0044] As shown in Fig. 7A, the furnace body M has annular vertical magnetic field coils 72A, 72B, 73A, and 73B centered on a vertical center line C1. The vertical magnetic field coils 72A and 72B are formed inside the coil 70. The vertical magnetic field coils 73A and 73B are formed outside the coil 70. Each of the vertical magnetic field coils 72A, 72B, 73A, and 73B 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 the coil housing.

[0045] 8A, the cryostat 40 has an upper wall 41 that covers the upper side of the coil 70. The cryostat 40 also has an inner wall 42 that is disposed inside the coil 70 (on the side of the vertical center line C1) and an outer wall 43 that is disposed outside the coil 70 (on the opposite side of the coil 70 from the inner wall 42). The cryostat 40 also has a bottom wall 44 that is disposed below the coil 70.

[0046] As shown in Figure 4, when multiple furnace modules (m) are arranged in the circumferential direction Dr of the furnace body M, in a plan view of the furnace body M, the upper wall 41 and the bottom wall 44 of the cryostat 40 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.

[0047] The blanket 50 has a plasma containing section 50W (see FIGS. 8B and 10A ) below it. When n furnace modules (m) are arranged in the circumferential direction Dr, the plasma containing section 50W has a cylindrical shape extending along the circumferential direction Dr of the furnace body M and is disposed inside the coil 70. As shown in FIG. 12 , the cryostat 40 has an inner shielding wall 45. The inner shielding wall 45 is formed between the plasma containing section 50W and the coil 70. The inner shielding wall 45 reduces the influence of heat on the coil 70.

[0048] The inner shielding wall 45 forms an airtight 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 containing section 50W where plasma is generated. In addition, the coil 70 can be insulated from other spaces within the vacuum vessel 20.

[0049] [Blanket] The blanket 50 includes n blanket module assemblies 50A (see FIG. 8B ). The n blanket 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. In the example described herein, the blanket 50 is composed of 10 blanket module assemblies 50A. These 10 blanket module assemblies 50A may have the same structure.

[0050] Each blanket module assembly 50A is composed of m blanket modules 51_1 to 51_9 (see FIG. 11). In the example described herein, each blanket module assembly 50A has nine blanket modules 51_1 to 51_9. The nine blanket modules 51_1 to 51_9 are combined to form one blanket module assembly 50A. Ten blanket module assemblies 50A are then arranged in the circumferential direction Dr to form the annular blanket 50. Hereinafter, when these nine blanket modules 51_1 to 51_9 need not be distinguished from one another, the blanket module will be referred to as "51."

[0051] The number of blanket module assemblies 50A and the number of blanket modules 51_1 to 51_9 may be changed according to the size of the reactor body M and the pitch of the coil 70 (the distance between two adjacent curved portions 70a and 70b (see Figure 7B)).

[0052] As shown in FIG. 11 , each blanket module 51 has a module lower section 52 at its bottom. The plasma containment section 50W ( FIGS. 10A and 10B ) is annular and centered on the vertical center line C1 of the reactor body M. The module lower sections 52 of each blanket module 51 are combined with each other to form a part of the annular plasma containment section 50W (a plasma containment section with a width corresponding to 360 / n degrees). Each blanket module 51 also has a module upper section 53 at its top that is supported by the upper wall 41 of the cryostat 40. Each blanket module 51 has a flow path section 54 that extends from the module upper section 53 toward the module lower section 52.

[0053] Radiation and particles from the plasma enter the lower module 52 (the portion forming the plasma containing section 50W) of the blanket module 51, deteriorating the material of the lower module 52. Therefore, the blanket module 51 requires periodic replacement and maintenance work. To make this work more efficient, each blanket module 51 can be moved upward through a gap formed in the coil 70 (the gap between two adjacent curved sections 70a, see FIG. 7B ).

[0054] In a plan view of the coil 70, each blanket module assembly 50A is disposed in this gap. Each blanket module 51 can be moved upward through this gap. Furthermore, a blanket module 51 after maintenance or a new blanket module 51 can be moved downward through this gap.

[0055] As described above, the upper wall 41 of the cryostat 40 covers the upper side of the coil 70. As shown in Fig. 8, the upper wall 41 has openings 41a formed therein that correspond to the gaps in the coil 70. The blanket module 51 can be moved up and down through these openings 41a.

[0056] [Structure Related to the Flow of Tritium Breeder Material] As described above, liquid metal is used as a tritium breeder material in the fusion reactor system 10. The blanket 50 is formed so that the tritium breeder material flows from the upper side to the lower side of the blanket 50. In other words, each blanket module 51 is configured so that the liquid tritium breeder material flows from the upper side to the lower side.

[0057] A supply port 53a for receiving tritium breeding material is formed in the upper part of the blanket 50. More specifically, as shown in FIG. 8B , the supply port 53a is formed on the upper surface of the module upper part 53. The reactor body M has a plurality of upper pools 61. A plurality of connection pipes 61a (see FIG. 10 ) connected to the supply ports 53a of the blanket modules 51 are formed in the bottom of the upper pool 61. Tritium breeding material is supplied to the upper pool 61 through the supply pipes 4c (see FIG. 3 ) from outside the vacuum vessel 20. That is, the tritium breeding material is poured from the supply pipes 4c into the upper pool 61 and supplied to each blanket module 51.

[0058] Each blanket module 51 is configured so that tritium breeder material flows through its interior from the module upper portion 53 to the module lower portion 52 via the flow path section 54. The blanket module 51 may be made of, for example, a porous material. Examples of materials that can be used for the porous blanket module 51 include titanium, titanium alloys, aluminum, high-manganese steel, ceramics such as tungsten, molybdenum, nickel, and silicon carbide, as well as combinations of these materials. Furthermore, using tungsten, molybdenum, nickel, or combinations of these materials for the blanket module 51 can adjust the wettability of the first wall of the fusion reactor (i.e., the wettability between the liquid metal tritium breeder and the blanket module 51). Alternatively, using ceramics such as silicon carbide can control the flow of liquid metal on the surface or inside of the blanket module 51. A flow path (e.g., a tube) for the tritium breeder material may be formed inside the flow path section 54.

[0059] The upper module portion 53 and the lower module portion 52 may be made of different materials. For example, the upper module portion 53 may be made of a material including titanium, a titanium alloy, aluminum, high manganese steel, or a combination thereof. The lower module portion 52 may have a base material including titanium, a titanium alloy, aluminum, high manganese steel, or a combination thereof, and the interior and / or surface 52g (the inner surface of the plasma containing portion 50W) of the lower module portion 52 may be made of a material including silicon carbide. The flow path portion 54 may be made of a material different from the lower module portion 52. For example, the flow path portion 54, like the upper module portion 53, may be made of a material including titanium, a titanium alloy, aluminum, high manganese steel, or a combination thereof. The interior and / or surface 52g of the lower module portion 52 may be formed of a material in which silicon carbide is filled into the base material of the lower module portion 52. Alternatively, the lower module portion 52 may be made of a material (alloy) including high manganese steel and silicon carbide.

[0060] The tritium breeder material passes through the interior of the blanket module 51 and leaks from the surface 52g (the inner surface of the plasma containment section 50W) of the module lower section 52, forming a free surface. This liquid breeder material can therefore function as the first wall of the fusion reactor. (In FIG. 10A, part of the flow of the leaked tritium breeder material is indicated by arrow F.)

[0061] 10A, a lower pool 62 that opens upward is disposed below the blanket module assembly 50A. The opening of the lower pool 62 may fit into the lower end of the blanket module assembly 50A.

[0062] The coil 70 has a plurality of curved portions 70a and 70b (see FIG. 7B) arranged in the circumferential direction Dr of the reactor body M. The curved portion 70a is located in the upper half of the coil 70, and the curved portion 70b is located in the lower half of the coil 70. Each pool 62 is disposed between two adjacent curved portions 70b. This allows the distance between the lower pool 62 and the plasma containing portion 50W of the blanket 50 to be reduced. In addition, an opening 44a (see FIG. 8A) is formed in the bottom wall 44 of the cryostat 40. The lower pool 62 is disposed inside this opening 44a.

[0063] 12, tritium breeding material leaking from the surface 52g of the plasma containing section 50W flows into the lower pool 62. An exhaust pipe 62b (see FIG. 10C) is connected to the lower pool 62. The exhaust pipe 62b 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.

[0064] The tritium breeder material discharged from the lower pool 62 is sent to the breeder material circulation system 4 (see FIG. 3 ) installed outside the vacuum vessel 20. The breeder material circulation system 4 has a heat exchanger 4a, a tank for storing the tritium breeder material, a pump for sending the tritium breeder material back to the upper pool 61 inside the vacuum vessel 20, and the like. The temperature of the tritium breeder material during operation of the fusion reactor system 10 can be 300°C or higher and 900°C or lower. The temperature of the tritium breeder material during operation of the fusion reactor system 10 can more preferably be 300°C or higher and 600°C or lower.

[0065] [Blanket Bottom Opening] An opening is formed in the bottom of the blanket 50 to allow tritium breeder material to flow downward (hereinafter, this opening will be referred to as the "blanket bottom opening"). In the fusion reactor system 10, a blanket bottom opening 55a (see FIG. 9B) is formed in the bottom of each blanket module assembly 50A. As shown in FIG. 9B, multiple blanket modules 51 are combined with each other to form the blanket bottom opening 55a. The space where plasma is generated and the lower pool 62 are in communication through the blanket bottom opening 55a. The blanket bottom opening 55a functions as a flow path for tritium breeder material to the lower pool 62. In addition, helium and the like from the divertor plasma generated near the blanket bottom opening 55a can be discharged into the lower pool 62 together with the tritium breeder material.

[0066] The blanket bottom opening 55a is located between two adjacent curved portions 70b (see FIG. 7B ) of the coil 70. A gap is formed between the two adjacent curved portions 70b. The shape of the blanket bottom opening 55a may be designed to fit the gap formed between the two curved portions 70b. For example, the width of the blanket bottom opening 55a may increase toward the outside in the radial direction of the furnace body M.

[0067] As described above, the tritium breeder material contains a large amount of tin, which has low hydrogen solubility. Therefore, tritium is released from the free surface of the tritium breeder material accumulated in the lower pool 62 without dissolving in the tritium breeder material. Some of this tritium passes through the blanket bottom opening 55a and returns to the space where plasma is generated (the space inside the plasma containment section 50W). Some of this tritium is then ionized and can be used as fuel. This allows the period during which only the DD reaction occurs to be shortened, for example, when operation is performed such that the DD reaction initially occurs but gradually transitions to the DT reaction as tritium accumulates.

[0068] [Openings Formed in the Plasma Containment Section] Furthermore, the remaining tritium (tritium not used as fuel) is discharged to the outside of the vacuum vessel 20 and processed in the above-described fuel circulation system 30. The blanket 50 may have openings or gaps formed therein that function as a flow path for tritium toward the exhaust device 31. For example, as shown in FIG. 10A , an opening 50a may be formed in the plasma containment section 50W of the blanket 50. (Hereinafter, this opening 50a will be referred to as the "inner opening.") The gas surrounding the plasma (gas containing tritium) flows, for example, through this inner opening 50a toward the exhaust device 31.

[0069] The inner opening 50a opens toward the inside of the plasma containing section 50W in the radial direction of the reactor body M. As shown in Fig. 5, a gas flow passage 42a connected to the inner opening 50a may be formed in the inner wall 42 of the cryostat 40. The gas flow passage 42a is located closer to the center of the fusion reactor body M than the inner opening 50a.

[0070] The plasma containing section 50W of the blanket 50 may be formed with a plurality of inner openings 50a aligned in the circumferential direction Dr of the furnace body M. Further, a gas flow passage 42a corresponding to each inner opening 50a is formed in the cryostat 40. The gas flow passage 42a is formed in a gap of the coil 70.

[0071] 10B , an opening 50b may be formed in the plasma containing section 50W of the blanket 50. (Hereinafter, this opening 50b will be referred to as the “outer opening.”) The gas surrounding the plasma (gas containing tritium) flows, for example, through this outer opening 50b toward the exhaust device 31.

[0072] The outer opening 50b opens toward the outside of the plasma containing unit 50W in the radial direction of the reactor body M. As shown in FIG. 6B , a gas flow path 43a connected to the outer opening 50b may be formed in the outer wall 43 of the cryostat 40. The gas flow path 43a opens into the vacuum vessel 20. The plasma containing unit 50W of the blanket 50 may be formed with a plurality of outer openings 50b aligned in the circumferential direction Dr of the reactor body M.

[0073] The gas flow path 43a may function as a path for pellets launched from the fuel supply device 36 (pellet injection device) described above, or as a path for particles (electrons and neutrons) for plasma heating.

[0074] 10C , for example, a gap G1 may be formed between the upper edge 62 a of the lower pool 62 and the blanket 50. Notches may be formed in at least the upper edge 62 a of the lower pool and the lower surface of the bracket 50 to ensure this gap G1. A gap G2 may also be formed between the lower pool 62 and a wall portion 44 b (a wall portion formed on the bottom wall 44) of the cryostat 40 surrounding the lower pool 62. These gaps G1 and G2 may function as flow paths for gas containing tritium. The gas flows through this flow path to the exhaust device 31.

[0075] [Summary] (1) The fusion reactor system 10 comprises a vacuum vessel 20, an exhaust device 31 connected to the vacuum vessel 20 and discharging gas within the vacuum vessel 20, a blanket 50 disposed within the vacuum vessel 20 and surrounding the space where plasma is formed, a tritium breeder material supplied to the blanket 50, and a fuel storage device 35 installed outside the vacuum vessel 20. The tritium breeder material is a liquid metal containing lithium and tin, and releases tritium produced in the tritium breeder material from the tritium breeder material within the vacuum vessel 20. The exhaust device 31 discharges the tritium released from the tritium breeder material to the fuel storage device 35 and outside the vacuum vessel 20. This structure makes it possible to simplify the fuel circulation system.

[0076] (2) In the fusion reactor system 10 of (1), the blanket 50 is formed so that the tritium breeder flows from the upper side to the lower side of the blanket 50. The vacuum vessel 20 accommodates a lower pool 62 that is disposed below the blanket 50 and receives the tritium breeder that has passed through the blanket 50. With this structure, tritium is released from the tritium breeder that has accumulated in the lower pool 62.

[0077] (3) The fusion reactor system 10 of (2) has a coil 70 that confines plasma. The coil 70 has a plurality of curved portions 70b spaced apart in the circumferential direction Dr of the fusion reactor main body M. Each of the plurality of pools 62 is disposed between two adjacent curved portions 70b.

[0078] (4) In the fusion reactor system 10 of (2) or (3), a blanket bottom opening 55a is formed at the bottom of the blanket 50. This opening 55a connects the space where plasma is generated with the lower pool 62, functions as a flow path for tritium breeder material to the lower pool 62, and returns tritium released from the tritium breeder material to the space where plasma is generated. This structure can facilitate the flow of tritium breeder material to the lower pool 62. Furthermore, tritium released from the tritium breeder material accumulated in the lower pool 62 can be returned to the space where plasma is generated. As a result, this tritium can be used as fuel.

[0079] (5) In the fusion reactor system 10 of (4), the blanket 50 is formed with openings 50a and 50b, which function as gas flow paths from the space where plasma is generated to the exhaust device 31, and gaps G1 and G2.

[0080] (6) The fusion reactor system 10 described in any one of (1) to (5) has a fuel purification device 33 that is arranged between the exhaust device 31 and the fuel storage device 35 and that purifies deuterium and tritium from the gas exhausted by the exhaust device 31.

[0081] (7) In the fusion reactor system 10 of (6), the tritium and deuterium refined in the fuel refinement device 33 are sent to the fuel storage device 35 without separation. The fuel storage device 35 stores the tritium and deuterium in a mixed state. This allows the fusion reactor system 10 to be further simplified.

[0082] (8) The fusion reactor system 10 of (7) has an auxiliary fuel storage device 38 that stores deuterium and adds deuterium to the tritium and deuterium stored in the fuel storage device 35. This allows the ratio of tritium to deuterium stored in the fuel storage device 35 to be optimized.

[0083] [Others] The structure proposed in the present disclosure may be applied to other plasma confinement methods, such as a tokamak-type nuclear fusion reactor system.

[0084] Furthermore, the arrangement of the pools that store the tritium breeding material is not necessarily limited to the example of the fusion reactor system 10. For example, the fusion reactor system 10 has a plurality of pools 62, and each pool 62 is arranged between two adjacent curved portions 70b of the coil 70. Alternatively, one pool that covers the entire underside of the blanket 50 may be arranged under the blanket 50.

[0085] 4: Breeder circulation system, 4a: Heat exchanger, 4c: Supply pipe, 10: Fusion reactor system, 20: Vacuum vessel, 21: Upper cover, 22: Outer wall, 30: Fuel circulation system, 31: Exhaust device, 32: Compressor, 33: Fuel purification device, 34: Compressor, 35: Fuel storage device, 36: Fuel supply device, 37: Exhaust device, 38: Auxiliary fuel storage device, 40: Cryostat, 41: Upper wall, 41a: Opening, 42: Inner wall, 42a: Gas flow path, 43: Outer wall, 43a: Gas flow path, 44: Bottom wall, 44a: Opening, 44b: Wall, 45: Inner shielding wall, 50: Blanket, 50A: Blanket module assembly body, 50W: plasma containing section, 50a: inner opening, 50b: outer opening, 51, 51_1 to 51_9: blanket module, 52: lower module section, 52g: surface, 53: upper module section, 53a: supply port, 54: flow path section, 55a: blanket bottom opening, 61: upper pool, 61a: connecting pipe, 62: lower pool, 62b: discharge pipe, 70: coil, 70a: curved section, 70b: curved section, 71: coil support, 71A and 71B: coil housing, 71a to 71d: hollow tubes, 72A, 72B, 73A, 73B: vertical magnetic field coils, C1: vertical center line, Dr: circumferential direction of fusion reactor body, M: fusion reactor body.

Claims

1. A nuclear fusion reactor system comprising: a vacuum vessel; an exhaust device connected to the vacuum vessel and exhausting gas within the vacuum vessel; a blanket placed within the vacuum vessel and surrounding a space in which plasma is formed; a tritium breeder material supplied to the blanket; and a fuel storage device installed outside the vacuum vessel, wherein the tritium breeder material is a liquid metal containing lithium and tin, and tritium produced by the tritium breeder material is released from the tritium breeder material within the vacuum vessel, and the exhaust device discharges the tritium released from the tritium breeder material to the outside of the vacuum vessel and toward the fuel storage device.

2. A fusion reactor system as described in claim 1, wherein the blanket is formed so that the tritium breeder material flows from the top to the bottom of the blanket, and the vacuum vessel contains at least one pool disposed below the blanket for receiving the tritium breeder material that has passed through the blanket.

3. The fusion reactor system according to claim 2, wherein the fusion reactor system has a coil for confining plasma, the coil having a plurality of curved portions spaced apart in the circumferential direction of the fusion reactor body, the at least one pool having a plurality of pools lined up in the circumferential direction, and each of the plurality of pools being disposed between two adjacent curved portions.

4. A nuclear fusion reactor system as described in claim 2, wherein an opening is formed in the bottom of the blanket, which connects the space where the plasma is formed with the pool, functions as a flow path for the tritium breeder material to the pool, and returns tritium released from the tritium breeder material to the space where the plasma is formed.

5. A nuclear fusion reactor system as described in claim 4, wherein the blanket has an opening formed therein that functions as a gas passage from the space where the plasma is formed to the exhaust device, and / or a gap is formed between the blanket and the pool.

6. A nuclear fusion reactor system as described in claim 1, further comprising a fuel purification device disposed between said exhaust device and said fuel storage device, for purifying deuterium and tritium from the gas discharged by said exhaust device.

7. A nuclear fusion reactor system as described in claim 6, wherein the tritium and deuterium refined in the fuel refinery are sent to the fuel storage device without separation, and the fuel storage device stores the tritium and deuterium in a mixed state.

8. A nuclear fusion reactor system according to claim 7, further comprising an auxiliary fuel storage device for storing deuterium and adding deuterium to the tritium and deuterium stored in said fuel storage device.

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