JP2018013459A - Nuclear fusion reactor blanket and support structure thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nuclear fusion reactor blanket which achieves high tritium proliferation performance while maintaining structural soundness of a blanket, and a support structure thereof.SOLUTION: A blanket 12 includes: a body outside wall 18 having an outside wall cylindrical part whose one opening end is closed by an outside wall spherical shell part; a body inside wall 19 having an inside wall cylindrical part whose one opening end is closed by an inside wall spherical shell part while being enclosed by the body outside wall 18, leaving a gap with the inner surface of the body outside wall 18, and having a proliferation material and a multiplication material inside; a flange 21 to which a pipe for supplying and recovering cooling water and a pipe for supplying and recovering emission gas are attached while closing the other opening end of the body 20; and a rib 25 for setting a passage for the cooling water supplied into the gap and recovered which is arranged at least either at a position where the passage of the cooling water on the outer surface of the inside wall spherical shell part is made narrow or at a position where turbulence of the cooling water flowing on the outer surface of the inside wall spherical shell part is caused to be generated.SELECTED DRAWING: Figure 4

Description

  Embodiments described herein relate generally to a fusion reactor blanket and a support structure thereof.

  In a nuclear fusion reactor, a mixed fuel containing deuterium and tritium (tritium) is held in plasma in a vacuum vessel, and energy is extracted from the primary neutrons of 14.1 MeV generated by the fusion reaction. Since tritium does not exist in nature, in order to operate the furnace continuously, it is necessary to multiply while supplementing the tritium consumption. For this reason, in the nuclear fusion reactor, a blanket is attached to the inner surface of the vacuum vessel in order to generate tritium by capturing neutrons generated by the fusion reaction and recover heat generated by the fusion reaction.

  As an example of a blanket, a tritium breeder containing lithium and a neutron multiplier containing beryllium in a box-shaped metal container (housing) made of specially-adjusted low activation ferritic steel (eg, F82H) Some layers are alternately provided. A flow path through which the cooling water flows is formed inside the housing, and the generated heat is recovered. A pipe for supplying and collecting cooling water and a pipe for supplying and collecting carrier gas for collecting generated tritium are attached to the casing.

  As another structural example of the blanket, a double wall is formed by a bell-shaped metal container, a pebble layer of lithium oxide is provided as a breeding material in the vicinity of the first wall facing the plasma, and the lithium oxide is disposed behind it. A method for arranging the blocks is also disclosed.

  In recent years, a cylindrical blanket composed of a double spherical shell portion and a double cylindrical portion has attracted attention as a method capable of achieving both a manufacturability and a relatively large tritium breeding ratio. This cylindrical blanket is configured to remove heat by flowing cooling water between double walls.

JP 2004-239807 A JP 2005-127960 A

Hiromasa Iida, et al., Nuclear characteristics of fusion experimental reactor blanket, JAERI-M 6460 (March 1976) Toshiba Corporation, Shiro Asano, etc., Development of Fusion Prototype Reactor, Toshiba Review, 2016 Vol. 71 no. 1

  By the way, in the design of a blanket that operates in an environment that receives neutron irradiation by fusion reaction and radiation from fusion plasma, (1) fuel multiplication performance, (2) heat removal performance, and (3) structural integrity. It is important to balance this.

  The fuel growth performance is evaluated by a tritium breeding ratio (TBD) representing a ratio between tritium production and consumption. Since the produced tritium has permeation leakage loss in the recovery process, it is desirable to achieve a tritium breeding ratio of 1.05 or more in the entire fusion reactor, and the blanket cannot be placed on the entire surface of the vacuum vessel. It is desirable to achieve a tritium breeding ratio of 1.25 or more with a blanket alone.

  Further, from the heat removal performance, the maximum temperature in service state required for the stability and soundness of the materials used for the housing material, the breeding material, and the multiplication material is set. In structural soundness, it is mainly applied when the thermal stress caused by the thermal gradient generated in the first wall close to the plasma, the water pressure due to the inclusion of high-temperature and high-pressure cooling water, or when the plasma disappears due to instability, etc. It must be able to withstand electromagnetic force.

  In the box-shaped blanket described above, when water pressure is applied due to water leakage inside the housing, high stress is generated at the center of each surface and at the structure discontinuity at the base of each surface. For this reason, it is necessary to prevent the generated stress of these parts from exceeding the allowable stress of the material, and if the casing becomes large, it is necessary to increase the plate thickness or to provide a reinforcing structure. If the plate thickness increases and the occupation ratio of the structural material increases, neutrons are attenuated and absorbed by the structural material, so that the tritium breeding ratio decreases.

  On the other hand, the cylindrical blanket has a structure in which the influence of internal stress is smaller than that of a box-type blanket and is strong against an increase in internal pressure. While the structure is highly safe, the temperature is highest at the spherical shell portion of the outer wall of the casing facing the plasma. The low activation ferritic steel, which is a candidate material for the housing, has a problem that it becomes brittle due to thermal aging when kept in a high temperature environment for a long time, and the upper temperature limit of the housing is about 550 ° C. 2).

  In order to satisfy this temperature upper limit value, the plate thickness upper limit value of the spherical shell portion of the outer wall of the housing is determined, and at the same time, the housing diameter is maintained in order to maintain pressure resistance against high-temperature and high-pressure cooling water (about 300 ° C.-15.5 MPa). The upper limit value and the plate thickness lower limit value of the cylindrical portion are inevitably determined. For this reason, when trying to withstand higher fusion power (higher heat load) for commercial fusion power generation, it is necessary to reduce the housing diameter, and the structure per unit area of the inner surface of the vacuum vessel Increases material occupancy.

  In this way, whether the blanket is box-shaped or cylindrical-shaped, the structural soundness of the blanket is reduced and the occupancy rate of the structural material is reduced while maintaining the structural soundness of the blanket. It was difficult to achieve high tritium breeding performance.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a fusion reactor blanket that realizes high tritium breeding performance while maintaining the structural integrity of the blanket, and a support structure thereof. And

  In the blanket for a nuclear fusion reactor according to an embodiment of the present invention, a housing outer wall having a cylindrical outer wall cylindrical portion, one open end of the outer wall cylindrical portion being closed to a spherical shell outer wall spherical shell portion, A cylindrical inner wall cylindrical portion, and the one open end of the inner wall cylindrical portion is closed to a spherical shell inner wall spherical shell portion, and an inner surface of the housing outer wall and a gap are provided to provide the housing outer wall. A housing inner wall including a breeding material for generating tritium by a nuclear reaction with neutrons and a multiplier for generating neutrons by a nuclear reaction with neutrons, and the inner wall and the housing A flange to which the other open end of the casing formed by the outer wall is closed, and a pipe for supplying and recovering cooling water into the casing and a pipe for supplying and recovering a discharge gas for recovering tritium And provided in the gap, Ribs for setting the flow path of the cooling water to be supplied and collected, wherein the flow path of the cooling water on the outer surface of the inner wall spherical shell portion is narrower than the flow path on the outer surface of the inner wall cylindrical portion And a rib disposed in at least one of the arrangements for generating a turbulent flow of the cooling water flowing on the outer surface of the inner wall spherical shell.

  According to an embodiment of the present invention, a blanket for a nuclear fusion reactor and a support structure thereof are provided that achieve high tritium breeding performance while maintaining the structural integrity of the blanket.

1 is a schematic cross-sectional view showing a configuration of a tokamak type nuclear fusion reactor. Explanatory drawing which shows the example of arrangement | positioning at the time of the nuclear reactor blanket concerning embodiment being arrange | positioned on the inner surface of a vacuum vessel. (A) is a perspective view which shows the structure of the blanket attached to the support body, (B) is a perspective view of the blanket which concerns on embodiment, (C) is a perspective view of the growth tube arrange | positioned inside a blanket. The longitudinal cross-sectional view which shows the structure of the blanket for fusion reactors which concerns on 1st Embodiment. II sectional drawing of FIG. (A) is a front view which shows the example of arrangement | positioning of the rib arrange | positioned at the housing inner wall of the fusion reactor blanket which concerns on embodiment, (B) is a side view of a housing inner wall, (C) is the upper surface of a housing inner wall. Figure. (A) is a front view which shows the example of arrangement | positioning of the rib arrange | positioned at the housing inner wall of the fusion reactor blanket which concerns on embodiment, (B) is a side view of a housing inner wall, (C) is the upper surface of a housing inner wall. Figure. (A) is a front view which shows the example of arrangement | positioning of the rib arrange | positioned at the housing | casing inner wall of the blanket for fusion reactors which concerns on embodiment, (B) is a side view of a housing | casing inner wall. (A) is a front view which shows the example of arrangement | positioning of the rib arrange | positioned at the housing | casing inner wall of the blanket for fusion reactors which concerns on embodiment, (B) is a side view of a housing | casing inner wall. (A) is a longitudinal cross-sectional view which shows the structure of the fusion reactor blanket which concerns on 2nd Embodiment, (B) is II-II sectional drawing of FIG. 10 (A). The cross-sectional view which shows the structure of the blanket for fusion reactors concerning 3rd Embodiment. (A) It is a longitudinal cross-sectional view which shows the structure of the fusion reactor blanket which concerns on 4th Embodiment, Comprising: The cross-sectional view at the time of arrange | positioning breeding material on the inner surface and flange surface of a housing | casing inner wall, (B) Inside of a housing | casing The longitudinal cross-sectional view at the time of increasing the arrangement | positioning amount of a breeding material gradually along the direction of a flange from the spherical shell part of a wall. The support structure of the blanket for fusion reactors concerning this embodiment.

(First embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional view showing a configuration of a tokamak type nuclear fusion reactor 10, and FIG. 2 is an arrangement example when the blanket 12 for a nuclear fusion reactor according to the embodiment is arranged on the inner surface of a vacuum vessel 11. It is explanatory drawing shown.

  In the nuclear fusion reactor 10, the mixed fuel containing deuterium and tritium is made into a plasma inside the vacuum vessel 11. The generated high-temperature plasma is held inside the vacuum vessel 11 by a magnetic field of a coil such as the superconducting coil 13. In the plasma, a fusion reaction between deuterium and tritium occurs. The diverter 14 exhausts helium and fuel particles generated by the fusion reaction, and discharges the thermal energy that has flowed to the diverter 14.

  The blanket 12 having a cylindrical housing is arranged on the inner surface of the vacuum vessel 11 so that the hemispherical part faces the plasma, that is, the hemispherical part becomes the first wall. Specifically, a plurality of blankets 12 are attached to a support (housing) 15, and the support 15 is installed on the inner surface of the vacuum vessel 11.

  The interior of the blanket 12 includes a breeding material for generating tritium by a nuclear reaction with neutrons and a multiplier for generating neutrons by a nuclear reaction with neutrons. The arrangement configuration of the breeding material and the multiplication material will be described later.

  In the blanket 12, upon receiving irradiation of primary neutrons generated by the fusion reaction, a nuclear reaction of lithium having a mass number of 6 contained in the breeding material is generated to generate tritium. At the same time, a nuclear reaction between beryllium and primary neutrons contained in the multiplier occurs to generate secondary neutrons. This secondary neutron also reacts with the breeding material in the blanket 12 to contribute to the generation of tritium.

  At the same time, in the blanket 12, heat generated from the plasma is recovered using the cooling water supplied and circulated inside the housing.

  FIG. 3A is a perspective view showing the configuration of the blanket 12 attached to the support body 15, and FIG. 3B shows a perspective view of the blanket 12 according to the embodiment. FIG. 3C shows a perspective view of the growth tube 17 inserted into the blanket 12.

  As shown in FIG. 3A, a plurality of blankets 12 are attached to the support 15. A large number of units are installed on the inner surface of the vacuum vessel 11 with the blanket group attached to the support 15 as one unit.

  The blanket 12 is provided with a cooling water pipe for supplying and recovering cooling water into the housing and a discharge gas pipe for supplying and recovering a discharge gas for recovering tritium via flanges. In FIG. 3B, the cooling water pipe and the carry-out gas pipe are collectively shown as 16.

  In the growth tube 17 shown in FIG. 3C, a growth layer filled with a growth material is formed inside and inserted into the blanket 12. The growth tube 17 is composed of four pipes having a U-shape. Three are arranged in parallel, and the remaining one is arranged in a direction perpendicular to the direction in which the other growth tubes 17 are arranged. The growth tube 17 is connected to the piping for unloading gas through a fringe. Tritium generated in the blanket 12 is recovered using this pipe.

  Specifically, an inert gas such as helium supplied as a carrier gas is circulated through the growth layer in the growth tube 17, and tritium released in a gaseous form from the growth layer is pushed out of the blanket 12 and recovered. . This tritium is recovered as a mixed gas with a carrier gas containing molecules having several chemical forms such as tritium hydrogen and tritium water vapor. Then, after only tritium is separated and recovered in the separation plant, it is used again as a fusion fuel.

  4 is a longitudinal sectional view of the blanket 12 according to the first embodiment, and FIG. 5 is a sectional view taken along the line II of FIG.

  The blanket 12 according to the first embodiment includes a housing 20 formed of a double wall of a housing outer wall 18 and a housing inner wall 19, a flange 21 for closing the housing 20, and a housing inner wall 19. It has at least a multiplication layer 22 and a multiplication layer 24 and a rib 25 provided inside. In FIG. 4, the configuration of the piping 16 that is attached to the blanket 12 via the flange 21 and supplies and recovers cooling water and carrier gas is omitted.

  The housing outer wall 18 has a cylindrical outer wall cylindrical portion, and one open end of the outer wall cylindrical portion is closed by a spherical shell-shaped outer wall spherical shell portion.

  The housing inner wall 19 has a cylindrical inner wall cylindrical portion, and one open end of the inner wall cylindrical portion is closed by a spherical shell-shaped inner wall spherical shell portion. The outer diameter of the inner wall cylindrical portion is smaller than the inner diameter of the outer wall cylindrical portion. Similarly, the outer diameter of the inner wall spherical shell is smaller than the inner diameter of the outer wall spherical shell.

  The housing inner wall 19 is disposed coaxially with the housing outer wall 18, and is enclosed in the housing outer wall 18 with a gap and an inner surface of the housing outer wall 18. Cooling water is supplied to the gap to remove heat from the blanket 12 heated by the heat generated by the plasma. The cooling water that has recovered the heat of the blanket 12 is recovered through a pipe.

  A proliferation tube 17 having a proliferation layer 22 filled with a proliferation material formed therein is inserted into the inner wall 19 of the housing. The inside of the growth pipe 17 has a multilayer structure, and a growth layer 22 is provided at the center. A refrigerant layer 23 for circulating cooling water is provided around the growth layer 22. The remaining space of the housing inner wall 19 in which the multiplication tube 17 is inserted is filled with a multiplication material to form a multiplication layer 24. As the growth material, helium is generated by neutron irradiation and the volume expands. Therefore, a sphere of lithium titanate having a diameter of 1 to 2 mm called a pebble is used. As the multiplier, beryllium spheres having a diameter of 1 to 2 mm are used.

  The flange 21 closes the other open end of the housing 20 formed by the housing outer wall 18 and the housing inner wall 19. A piping for supplying and recovering cooling water and a piping for supplying and recovering a discharge gas for recovering tritium are attached to the blanket 12 via the flange 21.

  The rib 25 is a plate for partitioning the gap provided in the gap formed by the inner surface of the casing outer wall 18 and the outer surface of the casing inner wall 19. By dividing the air gap by the rib 25, a flow path of the cooling water is set until the cooling water supplied from the air gap on the flange 21 side flows through the air gap and is collected via the air gap in the spherical shell portion. Is done.

  The rib 25 is provided fixed to the outer surface of the housing inner wall 19. Therefore, the housing outer wall 18 is formed so as to cover the housing inner wall 19 provided with the ribs 25 on the surface. The ribs 25 may be fixedly provided on the inner surface of the housing outer wall 18.

  The rib 25 has a cooling water flow path that flows through the space in the spherical shell portion (on the outer surface of the inner wall spherical shell portion) narrower than the flow path in the space of the cylindrical portion (on the outer surface of the inner wall cylindrical portion). Be placed. Or the rib 25 is arrange | positioned so that the turbulent flow of the cooling water which distribute | circulates the space | gap of a spherical shell part may be generated. The arrangement of the ribs 25 may be combined.

  Since the flow rate of the cooling water in the spherical shell portion increases as the flow path is set narrow, the heat transfer rate from the housing outer wall 18 to the cooling water in the spherical shell portion increases. Similarly, the cooling water flowing through the spherical shell portion is turbulent and the water is agitated, thereby increasing the heat transfer rate to the cooling water in the spherical shell portion. When the heat transfer rate from the housing outer wall 18 having the highest heat load close to the plasma region to the cooling water increases, the heat removal performance in the spherical shell portion of the housing 20 is promoted.

  FIG. 6 shows an arrangement example of the ribs 25 that increase the flow rate of the cooling water flowing through the spherical shell portion. In FIGS. 6 to 9, in order to show the flow of the cooling water, the description of the casing outer wall 18 is omitted, and only the casing inner wall 19 is described.

  6A is a front view of the inner wall, FIG. 6B is a side view of the inner wall, and FIG. 6C shows a top view of the inner wall.

  In the arrangement example of FIG. 6, the ribs 25 are arranged such that the width of the flow path becomes narrower toward the zenith of the spherical shell portion so that the flow velocity of the cooling water becomes the fastest at the zenith of the spherical shell portion. The flow path is set so as to be the narrowest. By arranging the ribs 25 in this way, the flow rate of the cooling water is increased near the zenith of the spherical shell. Thereby, the heat transfer coefficient near the zenith increases, and the heat removal performance in the spherical shell portion is promoted.

  FIG. 7 shows an arrangement example of the ribs 25 that increase the flow rate of the cooling water flowing through the spherical shell portion and turbulently flow the cooling water. 7A is a front view of the inner wall, FIG. 7B is a side view of the inner wall, and FIG. 7C shows a top view of the inner wall.

  In the arrangement example of FIG. 7, the ribs 25 are arranged with additional ribs 25 alternately in the vertical direction in the direction perpendicular to the direction in which the cooling water flows in the spherical shell portion. By setting a plurality of ribs 25 in a direction that hinders the direction in which the cooling water flows, the flow path is narrowed in the spherical shell portion and the flow rate of the cooling water is increased. At the same time, a turbulent flow of cooling water is generated to stir the water. As a result, the heat transfer coefficient in the spherical shell portion is increased and the heat removal performance is promoted.

  FIG. 8 shows another arrangement example of the ribs 25 that increase the flow rate of the cooling water flowing through the spherical shell portion and turbulently flow the cooling water. FIG. 8A is a front view of the inner wall, and FIG. 8B shows a side view of the inner wall.

  In FIG. 8, two semicircular ribs 25 are arranged near the zenith of the spherical shell portion in a direction that disturbs the direction in which the cooling water flows by shifting the center position. Due to the presence of the two semicircular ribs 25, the flow path width of the cooling water is narrowed in the spherical shell portion, the flow velocity is increased, and a turbulent flow of the cooling water is generated to stir the water in the spherical shell portion.

  FIG. 9 shows another arrangement example of the ribs 25 that increase the flow rate of the cooling water flowing through the spherical shell portion and turbulent the cooling water. FIG. 9A is a front view of the inner wall, and FIG. 9B shows a side view of the inner wall.

  In FIG. 9, the ribs 25 set in the spherical shell are arranged in a spiral shape, and the cooling water flows along the spiral. By the ribs 25 arranged in a spiral shape, the flow path width of the cooling water is narrowed in the spherical shell portion, the flow velocity is increased, and a turbulent flow of the cooling water is generated to stir the water in the spherical shell portion.

  Thus, by increasing the flow rate of the cooling water flowing through the spherical shell part, or by setting the rib 25 so that the cooling water turbulently flows, the thermal conductivity in the spherical shell part increases, and the heat removal performance. Promotes. Thereby, the heat load in a spherical shell part is reduced and the maximum temperature of the housing | casing 20 in a service state falls.

  When the maximum temperature of the casing 20 decreases, the upper limit value of the casing diameter determined according to the maximum temperature of the casing 20 is relaxed. For this reason, the diameter of the housing 20 (the housing outer wall 18 and the housing inner wall 19) can be increased. Thereby, since the ratio for which the structural material in the housing | casing 20 accounts can be reduced (because the ratio for a proliferation material and a multiplication material can be increased), attenuation | damping absorption of a neutron can be suppressed, a proliferation material and multiplication A high tritium breeding ratio can be achieved by increasing the number of neutrons that react with the material.

(Second Embodiment)
FIG. 10A is a longitudinal sectional view showing the configuration of the blanket 12 according to the second embodiment, and FIG. 10B shows a II-II section of FIG. 10A. 10, parts having the same configuration or function as those in the first embodiment (FIG. 4) are denoted by the same reference numerals, and redundant description is omitted.

  The blanket 12 in the second embodiment is different from the first embodiment in that the housing outer wall 18, the housing inner wall 19, and the rib 25 are joined via a welding member 26, and the housing outer wall 18 and the housing inner wall 19 are joined. It is in the point which united with. About the welding in the cylindrical part of the housing | casing 20, as shown to FIG. 10 (B), you may weld in planar shape along an axial direction with respect to the surface of a cylindrical part, and in several points of a cylindrical part You may weld in dot shape.

  For the joining, electron beam welding, laser welding, HIP (Hot Isostatic Press), diffusion joining, or the like is applied.

  The structural strength of the housing 20 can be increased by integrating the housing outer wall 18 and the housing inner wall 19. Further, by joining the housing outer wall 18 and the housing inner wall 19 with the rib 25 interposed therebetween, the rib 25 works as an auxiliary material for joining, and there is an effect that the structural strength is further increased.

  By increasing the structural strength of the housing 20, it is possible to reduce the plate thickness of the housing 20 and increase the diameter of the housing 20. Thereby, a high tritium breeding ratio can be realized. In FIG. 10, both the spherical shell portion and the cylindrical portion are joined via the welding member 26, but a configuration in which only one of them is joined may be used.

(Third embodiment)
FIG. 11 is a cross-sectional view showing the configuration of the blanket 12 according to the third embodiment. The vertical cross-sectional view is the same as FIG. 4 (vertical cross-sectional view of the first embodiment) except that the housing is a single wall and does not have the ribs 25, and thus description thereof is omitted.

  The blanket 12 in the third embodiment has a cylindrical cylindrical portion, and one of the open ends of the cylindrical portion is closed to a spherical shell portion, and a breeding material that generates tritium by a nuclear reaction with neutrons. A single wall casing 27 internally provided with a multiplier that generates neutrons by a nuclear reaction between neutrons and neutrons, and the other open end of the single wall casing 27 is closed to supply cooling water into the casing. It includes a pipe for collecting and a flange to which a pipe for supplying and collecting a carry-out gas for collecting tritium is attached, and a cooling water flow path 28 provided by drilling inside the wall surface of the cylindrical portion.

  In the third embodiment, the housing is a single wall, and the flow path 28 through which the cooling water flows is provided in the wall surface of the cylindrical portion. In the first embodiment (FIG. 4), the cooling water flow path is formed by the three members of the housing outer wall 18, the housing inner wall 19, and the rib 25. However, in the third embodiment, the cooling water is formed in the wall surface. The flow path is provided.

  The flow path 28 is formed by being perforated along the axial direction in the wall surface of the cylindrical portion. As shown in FIG. 10, a large number of flow paths 28 are provided in the wall surface of the single-wall casing 27 in the radial direction of the cylindrical portion. The flow path 28 formed along the axial direction in the wall surface of the cylindrical portion may be folded back at the end of the cylindrical portion to form a cooling water flow passage, and the flow of the cooling water inside the wall surface of the spherical shell portion. The flow path 28 may be perforated and connected to the flow path 28 in the cylindrical portion to form a cooling water flow passage through the spherical shell portion.

  The flow path 28 is formed by machining (gun drill or the like), electric discharge machining, electric field machining, or the like.

  Thus, when the flow path 28 is provided in the wall surface of the cylindrical portion, the distance from the surface of the casing that receives a thermal load to the cooling water is shortened, so that the heat removal performance is improved.

  Further, the circumferential stress generated in the flow path of the cooling water is proportional to (internal pressure of the flow path) × (radius of the casing) / (plate thickness of the casing). As shown in FIG. 4, when the casing 20 is configured with a double wall, the radius is the inner diameter R of the casing outer wall 18 (or the casing outer wall 18). On the other hand, in the blanket 12 according to the third embodiment, since the radius r of the flow path 28 is obtained, the circumferential stress is greatly reduced.

  For this reason, while being able to reduce the volume of a cooling water, the board thickness of a housing | casing can be reduced and a high tritium breeding ratio is realizable.

  Moreover, when comprised with a double wall like the blanket 12 which concerns on 1st Embodiment, it becomes difficult to confirm the soundness of the welding of the housing | casing inner wall 19 included in the housing | casing outer wall 18. FIG. On the other hand, since the blanket 12 according to the third embodiment is composed of a single casing, the soundness of welding can be confirmed.

  In addition, since the heat removal performance of the blanket 12 in which the flow path 28 is provided in the wall surface of the cylindrical portion is high, the cylindrical portion of the single-wall casing 27 may be disposed so as to be the first wall of plasma.

(Fourth embodiment)
FIG. 12A shows a configuration diagram of the blanket 12 according to the fourth embodiment. In FIG. 12, portions having the same configuration or function as those of the blanket 12 shown in the first embodiment (FIG. 4) are denoted by the same reference numerals, and redundant description is omitted.

  In the blanket 12 in the fourth embodiment, the breeding layer 22 containing a breeding material is provided in the vicinity of the inner surface of the casing inner wall 19 (the inner surface of the inner wall spherical shell and the inner wall cylindrical section) and in the casing inner wall 19 near the surface of the flange 21. Deploy. The method of arranging the breeding layer 22 is to provide an inner surface cover (not shown) formed along the vicinity of the inner surface of the housing inner wall 19 and fill the space between the cover and the inner surface of the housing inner wall 19 with the breeding material. To form. Similarly, an inner surface cover is provided in the vicinity of the surface of the flange 21, and the space between the cover and the surface of the flange 21 is filled with a breeding material.

  Thus, by arranging the breeding layer 22 so as to surround the inside of the inner wall 19 of the housing, it enters the housing 20 through the gap between the plasma facing surface and the adjacent blanket 12, and the structural material and cooling water The rate at which the multiplication layer 24 captures neutrons that are decelerated by the collisions and neutrons scattered backward from the multiplication layer 24 side increases. For this reason, a nuclear reaction is accelerated | stimulated and a tritium multiplication ratio can be improved.

  12 (B) and 12 (A) show a modified example of the blanket 12, and the breeding layer 22 disposed in the vicinity of the inner surface of the cylindrical portion of the housing inner wall 19 extends along the flange direction from the spherical shell side. So that the thickness gradually increases. Note that it is desirable that the breeding layer provided near the surface of the flange 21 be thicker.

  Lithium, which is a breeding material, has the property of increasing the reaction cross section on the low energy side. On the other hand, the neutron spectrum on the plasma side has a high energy and gradually attenuates as it approaches the flange 21 side, and the low energy component increases. That is, by increasing the thickness of the growth material on the flange 21 side where there are many low energy neutrons, the nuclear reaction is promoted, and the tritium growth ratio can be improved.

  FIG. 13 shows a support structure for the blanket 12 according to the present embodiment. In addition, as the blanket 12 applied to the support structure, any of the blankets 12 according to the first to fourth embodiments can be applied.

  The support 15 that supports the plurality of blankets 12 includes a shielding portion 33 that prevents neutron leakage to the outside of the fusion reactor. For this reason, neutrons that have not undergone nuclear reaction with the breeding material and multiplication material in the blanket 12 are shielded (lost) by the shielding part 33.

  In the support structure for the blanket 12 according to the present embodiment, the neutron reflector 32 is disposed between the blanket 12 and the shielding part 33 in order to prevent the loss of neutrons in the shielding part 33.

  Specifically, the neutron reflector 32 is installed on the surface of the support 15 that supports the plurality of blankets 12 that faces the plasma. Note that examples of the material of the neutron reflector 32 include graphite and tungsten.

  In this way, the neutron is reflected by using the neutron reflector 32 and returned again to the regions of the multiplication layer 22 and the multiplication layer 24 inside the blanket 12 to cause a nuclear reaction. Thereby, a nuclear reaction is accelerated | stimulated and a tritium multiplication ratio can be improved.

  According to the fusion reactor blanket of each embodiment described above, the flow rate of the cooling water flowing through the spherical shell portion is increased or the cooling water is turbulent using the ribs provided in the gaps in the double walls. As a result, the thermal conductivity of the cooling water increases and the temperature of the housing can be reduced. As a result, the diameter of the housing can be increased, and the proportion of the structural material in the housing can be reduced (because the proportion of the breeding material and the multiplication material can be increased), so a high tritium breeding rate. Can be realized.

  In addition, heavy water may be used instead of water as the cooling water supplied into the blanket. Heavy water has a smaller neutron absorption cross-section and less neutron attenuation than light water. For this reason, since the ratio of the neutron which reacts with a propagation material is high, it contributes to tritium production | generation.

  Therefore, by using heavy water, even if the volume of the cooling water flow path is increased, the decrease in the tritium growth ratio is small, so the heat removal performance is improved by increasing the flow volume of the cooling water, It is also possible to reduce the flow velocity. If the flow rate of the cooling water is reduced, the corrosion allowance of the structural material can be reduced, so that it is possible to extend the life of the equipment and reduce the thickness of the structural material.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 10 ... Fusion reactor, 11 ... Vacuum vessel, 12 ... Blanket for fusion reactor, 13 ... Superconducting coil, 14 ... Diverter, 15 ... Support, 16 ... Pipe, 17 ... Breeding tube, 18 ... Housing Outer wall, 19 ... Inner wall, 20 ... Housing, 21 ... Flange, 22 ... Proliferation layer, 23 ... Refrigerant layer, 24 ... Multiplier layer, 25 ... Rib, 26 ... Welding member, 27 ... Single wall housing, 28 ... channel, 32 ... neutron reflector, 33 ... shielding part.

Claims (11)

A housing outer wall having an outer wall cylindrical portion, wherein one open end of the outer wall cylindrical portion is closed to the outer wall spherical shell;
An inner wall cylindrical portion, the one open end of the inner wall cylindrical portion is closed by an inner wall spherical shell portion, and an inner surface and a gap are provided in the outer wall of the housing so that the inner wall is enclosed in the outer wall of the housing. A housing inner wall with a doubler,
A flange to which piping including cooling water piping for supplying and recovering cooling water into the housing is closed by closing the other open end of the housing formed by the housing inner wall and the housing outer wall; ,
A rib that is provided in the gap and sets the flow path of the cooling water, the flow rate of the cooling water on the outer surface of the inner wall spherical shell portion being higher than the flow rate on the outer surface of the inner wall cylindrical portion; and And a rib arranged in at least one of the arrangements for generating a turbulent flow in the cooling water on the inner wall spherical shell. A housing outer wall having a cylindrical outer wall cylindrical portion, wherein one open end of the outer wall cylindrical portion is closed to a spherical shell outer wall spherical shell portion;
A cylindrical inner wall cylindrical portion, and the one open end of the inner wall cylindrical portion is closed to a spherical shell inner wall spherical shell portion, and an inner surface and a gap are provided on the outer wall of the housing, A housing inner wall that is internally encapsulated with a multiplication material that generates tritium by a nuclear reaction with neutrons and a multiplication material that generates neutrons by a nuclear reaction with neutrons;
Closing the other open end of the casing formed by the casing inner wall and the casing outer wall, supplying piping for supplying and recovering cooling water into the casing, and supply gas for recovering tritium, and A flange with a pipe to be collected;
Ribs provided in the gap and configured to set a flow path of the cooling water that is supplied to and recovered in the gap, and the flow path of the cooling water on the outer surface of the inner wall spherical shell portion is the outer surface of the inner wall cylindrical portion. And a rib disposed in at least one of an arrangement that is narrower than the upper flow path and an arrangement that generates a turbulent flow of the cooling water that circulates on the outer surface of the inner wall spherical shell portion. Blanket for fusion reactor.   The said rib is set so that the width | variety of a flow path may become narrow as it approaches the zenith of the said inner wall spherical shell part, and the flow path is set so that it may become the narrowest in the said zenith. A blanket for a nuclear fusion reactor as described in 2.   The fusion reactor according to any one of claims 1 to 3, wherein the rib is added on the outer surface of the inner wall spherical shell portion in a direction opposite to a flow direction of the cooling water. blanket.   The case outer wall, the case inner wall, and the rib are joined via a welding member to integrate the case outer wall and the case inner wall. A blanket for a nuclear fusion reactor according to any one of the above.   The proliferation layer containing the proliferation material is disposed in the vicinity of the inner surface of the inner wall of the casing and in the vicinity of the surface of the flange in the inner wall of the casing. Blanket for fusion reactor.   The fusion layer according to claim 6, wherein the proliferation layer disposed on the inner wall cylindrical portion is disposed so that the proliferation layer gradually increases along the flange direction from the inner wall spherical shell side. Furnace blanket. A cylindrical portion having a cylindrical shape, and the one open end of the cylindrical portion is closed to a spherical shell portion, and by a nuclear reaction between a breeding material and a neutron that generates tritium by a nuclear reaction with a neutron A single-wall housing with a multiplier to generate neutrons inside,
A flange to which the other open end of the single wall casing is closed, a pipe for supplying and recovering cooling water into the single wall casing, and a pipe for supplying and recovering a discharge gas for recovering tritium; ,
A blanket for a nuclear fusion reactor, comprising: a flow path for the cooling water provided by drilling inside a wall surface of the cylindrical portion.   9. The blanket for a nuclear fusion reactor according to claim 8, wherein the cooling water flow path is provided in a wall surface of the spherical shell portion.   The fusion reactor blanket according to any one of claims 1 to 9, wherein the cooling water is heavy water. A support structure for a fusion reactor blanket,
A blanket for a nuclear fusion reactor according to any one of claims 1 to 10,
A support for supporting the plurality of fusion reactor blankets;
A support structure for a fusion reactor blanket, comprising: a neutron reflector provided on a surface of the support opposite to the plasma.

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