Nuclear reactor

Abstract

To enable absorption of differential thermal expansion while ensuring thermal conductivity performance.SOLUTION: A nuclear reactor is disclosed, comprising a reactor core 11 comprising nuclear fuel 22 and a support body 21 for transferring heat of the nuclear fuel 22, heat transfer tubes 41 inserted to holes 21b formed through the support body 21, and a thermally conductive gap material 42 filling a gap between the support body 21 and the heat transfer tube 41 in each hole 21b to absorb differential thermal expansion therebetween.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to nuclear reactors. [Background technology]

[0002] For example, Patent Document 1 describes a nuclear reactor that includes a nuclear fuel section and a heat conducting section, with the heat conducting section being provided so as to protrude from the fuel section. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7426323 Summary of the Invention [Problem to be solved by the invention]

[0004] The nuclear reactor described in Patent Document 1 transfers heat from the nuclear fuel section to the heat conduction section through solid-state thermal conduction. In such a reactor, if there is a difference in thermal expansion between each fuel section and the heat conduction section, the one with the larger expansion will place a load on the other with the smaller expansion. Therefore, it is conceivable to provide a gap between the two, but solid-state thermal conduction cannot ensure heat conduction performance without contact between the two.

[0005] The present disclosure is intended to solve the above-mentioned problems, and aims to provide a nuclear reactor that can absorb thermal expansion differences while ensuring heat conduction performance. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a nuclear reactor according to one embodiment of the present disclosure includes a core including nuclear fuel and a support that transfers heat from the nuclear fuel, a heat transfer tube inserted into a hole formed in the support, and a gap material that is filled in the hole between the support and the heat transfer tube to absorb the thermal expansion difference between them and have heat transfer performance. [Effects of the Invention]

[0007] The present disclosure can absorb the thermal expansion difference while ensuring the thermal conductivity performance. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a nuclear power generation system using a nuclear reactor according to an embodiment. [Figure 2] FIG. 2 is a vertical cross-sectional view of the nuclear reactor according to the embodiment. [Figure 3] FIG. 3 is a cross-sectional plan view of the nuclear reactor according to the embodiment. [Figure 4] FIG. 4 is an enlarged cutaway view of a nuclear reactor according to an embodiment. [Figure 5] FIG. 5 is an enlarged cross-sectional view of a nuclear reactor according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to these embodiments. Furthermore, the components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially identical.

[0010] FIG. 1 is a schematic diagram of a nuclear power generation system using a nuclear reactor according to an embodiment.

[0011] As shown in FIG. 1, the nuclear power generation system 100 includes a nuclear reactor 101, a refrigerant circulation path 102, a turbine 103, a compressor 104, a generator 105, a heat exchanger 106, and a cooler 107.

[0012] The reactor 101 has a reactor vessel 111, a reactor core 112, and a heat conduction section 113. The reactor vessel 111 houses the reactor core 112 inside. The reactor vessel 111 houses the reactor core 112 in a sealed state. The reactor vessel 111 is provided with an opening / closing section, such as a lid, so that the reactor core 112 placed inside can be stored or removed. The reactor vessel 111 can maintain a sealed state even when a nuclear reaction occurs in the reactor core 112 and the inside becomes hot and high pressure. The reactor vessel 111 is made of a material with thermal insulation properties.

[0013] The reactor core 112 contains nuclear fuel, and generates heat by causing a nuclear reaction with the nuclear fuel. The heat conduction section 113 extracts the heat generated in the reactor core 112 to the outside. Details of the reactor core 112 and the heat conduction section 113 will be described later.

[0014] The refrigerant circulation path 102 is a path for circulating a cooling medium (also referred to as a refrigerant). The refrigerant circulation path 102 connects the reactor 101 to the turbine 103, the heat exchanger 106, the cooler 107, the compressor 104, and the heat exchanger 106 in this order in the flow direction of the cooling medium, and is then connected back to the reactor 101. The high-temperature cooling medium extracted from the reactor 101 flows through the refrigerant circulation path 102, passes through the turbine 103, the heat exchanger 106, the cooler 107, the compressor 104, and the heat exchanger 106 in this order, and returns to the reactor 101.

[0015] The turbine 103 and the compressor 104 are connected by a connecting shaft 108 and are rotatable integrally. The compressor 104 is connected to a generator 105 by a connecting shaft 109, and the driving torque of the turbine 103 and the compressor 104 is transmitted to the generator 105. The turbine 103 is driven to rotate by the cooling medium heated by the reactor 101, and transmits the driving torque to the compressor 104. The compressor 104 is driven to rotate by the driving torque transmitted from the turbine 103 via the connecting shaft 108, and compresses the cooling medium cooled by the cooler 107. The generator 105 is driven by the driving torque transmitted from the compressor 104 via the connecting shaft 109 to generate electricity.

[0016] The heat exchanger 106 exchanges heat between the cooling medium that has been heated by the reactor 101 and then driven the turbine 103 and the cooling medium that has driven the compressor 104 .

[0017] The cooler 107 cools the cooling medium that has been subjected to heat exchange in the heat exchanger 106 after driving the turbine 103. The cooler 107 cools the cooling medium by exchanging heat between the cooling medium flowing through the refrigerant circulation path 102 and a secondary cooling medium.

[0018] The heat generated by the reaction of the nuclear fuel in the reactor core 112 is extracted via the heat conduction unit 113. That is, the heat conduction unit 113 heats the cooling medium using the heat from the reactor core 112 and causes the high-temperature cooling medium to flow through the refrigerant circulation path 102. The cooling medium flowing through the refrigerant circulation path 102 is supplied to the turbine 103.

[0019] The turbine 103 is driven to rotate by the cooling medium flowing through the refrigerant circulation path 102, and transmits the driving rotation force to the compressor 104. The cooling medium that has driven the turbine 103 flows through the heat exchanger 106 to the cooler 107 and is cooled. The cooling medium cooled by the cooler 107 is supplied to the compressor 104. The compressor 104 is driven to rotate by the driving rotation force transmitted from the turbine 103 via the connecting shaft 108, and compresses the cooling medium supplied from the cooler 107.

[0020] At this time, the generator 105 is driven by the driving torque transmitted from the compressor 104 via the connecting shaft 109 to generate electricity.

[0021] The cooling medium that has driven the compressor 104 is supplied to the heat exchanger 106. The heat exchanger 106 exchanges heat between the cooling medium that has driven the turbine 103 and the cooling medium that has driven the compressor 104. That is, the heat exchanger 106 heats the low-temperature cooling medium that has driven the compressor 104 with the high-temperature cooling medium that has driven the turbine 103.

[0022] The cooling medium heated by the heat exchanger 106 is then returned to the reactor core 112 .

[0023] The nuclear power generation system 100 extracts heat from a reactor core 112 using a cooling medium through a heat conduction section 113, drives a turbine 103 with the high-temperature, high-pressure cooling medium, and generates electricity using a generator 105.

[0024] Fig. 2 is a longitudinal sectional view of a nuclear reactor according to an embodiment. Fig. 3 is a plan sectional view of a nuclear reactor according to an embodiment. Fig. 4 is an enlarged cutaway view of a nuclear reactor according to an embodiment. Fig. 5 is an enlarged cutaway view of a nuclear reactor according to an embodiment.

[0025] 2, the reactor 101 has a reactor vessel 111, a reactor core 112, a heat conduction section 113, and a support plate 114. The reactor core 112 is housed inside the reactor vessel 111, and is provided with the heat conduction section 113. The heat conduction section 113 extracts heat generated in the reactor core 112 to the outside.

[0026] The reactor core section 112 has the reactor core 11, the shielding section 12, the heat transfer tubes 41 constituting the thermal conductor 40, and the reactivity control device 14. The reactor core section 112 has a cylindrical shape and is arranged vertically with its central axis O aligned vertically.

[0027] In the embodiment, the core 11 is formed so that the overall outer shape is a hexagonal prism centered on the central axis O, as shown in Fig. 3. The core 11 has, for example, a plurality of fuel blocks 20 (six in the embodiment) each having a triangular prism outer shape arranged along the circumferential direction around the central axis O, and forms an overall hexagonal prism shape that is long in the axial direction along the central axis O. The shape of the core 11 is not limited to a hexagonal prism shape, and may be a polygonal prism shape or a cylindrical shape.

[0028] As shown in FIGS. 4 and 5 , the fuel block 20 has a support 21. The support 21 forms the outer shape of the fuel block 20. The support 21 constitutes a heat conductor, and may be made of, for example, graphene or graphite. The support 21 has nuclear fuel (radioactive material) 22. The nuclear fuel 22 is arranged, for example, by being inserted into a hole 21a formed in the support 21 along the axial direction. The nuclear fuel 22 is fitted to correspond to the shape of the hole 21a of the support 21 and may have, for example, a cylindrical shape. The nuclear fuel 22 may be in the form of a rod that is continuous in the axial direction, or in the form of pellets that are discontinuous in the axial direction. The nuclear fuel 22 may be made of fissionable material such as uranium (e.g., uranium-235), plutonium (e.g., plutonium-239, plutonium-241), or thorium.

[0029] The shielding section 12 is arranged to surround the reactor core 11. The shielding section 12 is made of a metal block and prevents radiation from leaking to the outside by reflecting radiation (neutrons) emitted from the nuclear fuel that makes up the reactor core 11. The shielding section 12 is sometimes called a reflector depending on the neutron scattering and neutron absorption capabilities of the material used.

[0030] The shielding part 12 has a body 31, a bottom 32, and a lid 33. The body 31 is cylindrical and disposed radially outside the core 11. That is, the body 31 covers the outer periphery of the core 11 so as to surround it. The bottom 32 is disk-shaped and disposed on one axial side of the body 31. That is, the bottom 32 covers the lower part of the core 11 so as to close it. The lid 33 is disk-shaped and disposed on the other axial side of the body 31. That is, the lid 33 covers the upper part of the core 11 so as to close it. When the shielding part 12 accommodates the core 11 inside, it is preferable to fill the sealed interior with an inert gas such as nitriding gas in order to prevent oxidation inside.

[0031] The support plates 114 support the core 11 inside the reactor vessel 111. The support plates 114 are formed in a disk shape centered on the central axis O and are attached inside the reactor vessel 111. The support plates 114 are paired, and a bottom portion 32 and a lid portion 33 that cover the periphery of the core 11 are fixed to each other. That is, by fixing the bottom portion 32 and the lid portion 33 to each other, each support plate 114 supports the shielding portion 12 inside the reactor vessel 111 so as to sandwich the core 11 from above and below.

[0032] The heat conduction section 113 is composed of a heat conductor 40. That is, the heat conductor 40 conducts heat generated in the reactor core 11 to the outside of the reactor vessel 111. The heat conductor 40 includes a heat transfer tube 41, a gap member 42, an inlet manifold 43A, an outlet manifold 43B, an inlet pipe (piping) 44A, an outlet pipe (piping) 44B, and expansion pipes 45A and 45B, as shown in FIGS. 2, 4, and 5.

[0033] A large number of heat transfer tubes 41 are arranged so as to penetrate the reactor core 11 in the axial direction. The heat transfer tubes 41 are made of copper or the like, which has a relatively high thermal conductivity. The heat transfer tubes 41 are inserted into holes 21b formed in the support body 21 of the fuel block 20 along the axial direction in the reactor core 11, and are arranged so as to penetrate into the interior of the reactor core 11. One end of the heat transfer tube 41 penetrates the cover 33 and support plate 114 of the shielding part 12, and the other end penetrates the bottom 32 and support plate 114 of the shielding part 12, and extends to the outside of the reactor core 11 in the axial direction.

[0034] The gap material 42 is arranged in the hole 21b of the support 21, filling the gap between the support 21 and the heat transfer tube 41. That is, the gap material 42 is arranged in the hole 21b, filling the gap between the support 21 and the heat transfer tube 41. The gap material 42 is made of any of copper, boron nitride, solid lubricant paste, carbon nanotubes, and powdered graphite, which are deformable and have a relatively high heat transfer coefficient and heat transfer performance.

[0035] The inlet manifold 43A is disposed inside the reactor vessel 111, and is connected to one ends of the numerous heat transfer tubes 41 that penetrate the reactor core 11. That is, the inlet manifold 43A is connected to one end of each heat transfer tube 41 collectively inside the reactor vessel 111. The inlet manifold 43A is supported movably with respect to the reactor vessel 111. For example, as shown in Fig. 2, the inlet manifold 43A is suspended from a movable hanger (constant hanger) 115 with respect to the reactor vessel 111, and is supported movably in the axial direction and in a radial direction intersecting the axial direction.

[0036] The outlet manifold 43B is disposed inside the reactor vessel 111, and is connected to the other ends of the multiple heat transfer tubes 41 that have penetrated the reactor core 11. That is, the outlet manifold 43B is connected to a group of the other ends of the heat transfer tubes 41 inside the reactor vessel 111. The outlet manifold 43B is fixed to the reactor vessel 111.

[0037] The inlet piping 44A is connected to the inlet manifold 43A inside the reactor vessel 111. The inlet piping 44A is fixed while passing through the reactor vessel 111, extends from the inside of the reactor vessel 111 to the outside, and is connected to the coolant circulation path 102.

[0038] The outlet pipe 44B is connected to a portion of the outlet manifold 43B that extends to the outside of the reactor vessel 111. The outlet pipe 44B is connected to the coolant circulation path 102 outside the reactor vessel 111.

[0039] The expansion pipes 45A, 45B are formed to be extendable and contractible. For example, bellows-shaped pipes are used as the expansion pipes 45A, 45B. The expansion pipes 45A, 45B are interposed in the inlet piping 44A inside the reactor vessel 111. The inlet piping 44A is arranged in a bent state inside the reactor vessel 111 so as to have an axially extending portion and a radially extending portion. The expansion pipe 45A is interposed in the axially extending portion of the inlet piping 44A so as to be extendable and contractible in the axial direction. The expansion pipe 45B is interposed in the radially extending portion of the inlet piping 44A so as to be extendable and contractible in the radial direction. The expansion pipes may be configured to be movable axially and radially as a single unit, in which case they are appropriately interposed in the inlet piping 44A inside the reactor vessel 111.

[0040] In the embodiment, the heat conductor 40 (heat conduction portion 113) includes a heat transfer tube 41, an inlet manifold 43A, an outlet manifold 43B, an inlet pipe (piping) 44A, an outlet pipe (piping) 44B, and expansion tubes 45A and 45B, which form a circulation path with the reactor core 11 inside the reactor vessel 111 and a refrigerant circulation path 102 outside the reactor vessel 111. The circulation path formed by the heat conductor 40 is filled with a refrigerant (e.g., carbon dioxide), allowing the refrigerant to flow. That is, the refrigerant is supplied to one end of the heat transfer tube 41, flows through the reactor core 11, and is discharged to the outside through the other end of the heat transfer tube 41. At this time, the refrigerant in the heat conductor 40 is heated by heat generated by the nuclear reaction of the nuclear fuel 22 in the reactor core 11, and extracts the heat to the outside. The refrigerant in the heat conductor 40 is then sent to the refrigerant circulation path 102.

[0041] In the thermal conductor 40, heat generated by the nuclear reaction of the nuclear fuel 22 in the reactor core 11 is transferred to the heat transfer tubes 41 by solid-state thermal conduction via the support 21 of the fuel block 20. In the nuclear reactor 101 of the embodiment, by transferring heat by solid-state thermal conduction, there is no leakage of radiation due to leakage of the coolant, as compared to heat transfer by a fluid coolant, and a high output temperature can be ensured.

[0042] The thermal conductor 40 transfers heat generated by the nuclear reaction of the nuclear fuel 22 in the reactor core 11 to the heat transfer tubes 41 via the support 21 of the fuel block 20. The gap material 42 is filled between the support 21 and the heat transfer tube 41 in the hole 21b, and transfers heat from the support 21 to the heat transfer tube 41. Furthermore, the heat conductor 40 expands due to the difference in thermal expansion (difference in linear expansion coefficient) between the heat transfer tube 41 and the support 21 due to heat. This difference in thermal expansion of the heat transfer tube 41 is absorbed by the deformation of the gap material 42.

[0043] In the thermal conductor 40, the heat transfer tubes 41 expand in the axial direction due to the difference in thermal expansion between them and the support body 21 due to heat. The inlet manifold 43A, to which one end of the heat transfer tube 41 is connected, is suspended by a movable hanger (constant hanger) 115 and supported so as to be movable in the axial and radial directions, and therefore moves in accordance with the expansion of the heat transfer tubes 41. Any displacement that may occur between the core 11 and the reactor vessel 111 due to this movement of the inlet manifold 43A is absorbed by the expansion tubes 45A and 45B.

[0044] The reactivity control device 14 is disposed in the shielding portion 12. The reactivity control device 14 is disposed so as to surround the periphery of the reactor core 11. The reactivity control device 14 has a plurality of (in this embodiment, 12) control drums (control portions) 51. The number of control drums 51 is not limited. The plurality of control drums 51 are disposed in the body 31 of the shielding portion 12, outside the reactor core 11, at intervals (preferably at equal intervals) in the circumferential direction. The plurality of control drums 51 are disposed outside the plurality of fuel blocks 20 that constitute the reactor core 11. The control drum 51 has a cylindrical shape and is disposed along the axial direction of the reactor core 11. The control drum 51 has approximately the same length as the reactor core 11. The control drum 51 is supported relative to the shielding portion 12 so as to be rotatable about an axis along the central axis O.

[0045] The control drum 51 has a drum main body 54, a neutron absorbing section 55, and a neutron reflecting section 56. The control drum 51 is configured such that the neutron absorbing section 55 and the neutron reflecting section 56 are provided on a portion of the drum main body 54 in the circumferential direction. The drum main body 54 may be made of, for example, graphene. The neutron absorbing section 55 may be made of, for example, boron carbide (B4C). The neutron reflecting section 56 may be made of, for example, beryllium oxide (BeO). The neutron reflecting section 56 is not limited to beryllium oxide, and may also be made of, for example, NgO. Here, the neutron absorbing section 55 has higher neutron absorption performance than the drum main body 54, the neutron reflecting section 56, and the shielding section 12. The neutron reflecting section 56 has higher neutron reflection performance than the drum main body 54, the neutron absorbing section 55, and the shielding section 12.

[0046] As the control drum 51 rotates, the circumferential positions of the neutron absorbing section 55 and the neutron reflecting section 56 on the drum body 54 change. That is, as the control drum 51 rotates, the neutron absorbing section 55 and the neutron reflecting section 56 move closer to or further away from the core 11. When the neutron absorbing section 55 moves closer to the core 11, the reactivity of the nuclear fuel 22 in the core 11 decreases, and when the neutron absorbing section 55 moves further away from the core 11, the reactivity of the nuclear fuel 22 increases. In this way, the control drum 51 can control the reactivity of the nuclear fuel 22 by moving closer to or further away from the core 11 through the rotation of the neutron absorbing section 55, thereby controlling the core temperature of the core 11. The core temperature is the average core temperature that is taken out to the outside of the shielding section 12 by the thermal conductor 40.

[0047] Although not shown in the figure, the reactivity control device 14 includes a control device and a drive unit. The control device controls the drive unit to control the rotational positions of the multiple control drums 51. The control device is, for example, a computer, and is realized by an arithmetic processing device including a microprocessor such as a CPU (Central Processing Unit).

[0048] In the core section 112, the core 11 (fuel block 20) ​​may be configured by stacking a plurality of plate-shaped fuel plates containing nuclear fuel in the axial direction. Also, in the core section 112, the shielding section 12 may be configured by stacking a plurality of plate-shaped shielding plates in the axial direction.

[0049] The nuclear reactor 101 of the above-described embodiment is characterized by including a core 11 including nuclear fuel 22 and a support 21 that transfers the heat of the nuclear fuel 22, a heat transfer tube 41 inserted into a hole 21b formed in the support 21, and a gap material 42 that is packed between the support 21 and the heat transfer tube 41 in the hole 21b to absorb the thermal expansion difference between them and have heat transfer performance.

[0050] According to this reactor 101, by filling the gap material 42 between the support 21 and the heat transfer tube 41 in the hole portion 21b, the support 21 and the heat transfer tube 41 are brought into close contact with each other, ensuring heat transfer performance through solid thermal conduction and reducing stress caused by the difference in thermal expansion between the support 21 and the heat transfer tube 41.

[0051] In addition, the reactor 101 of the embodiment further includes a reactor vessel 111 that accommodates the reactor core 11, a pipe 44A that is arranged inside the reactor vessel 111 and connected to the heat transfer tube 41, and expansion pipes 45A, 45B that are interposed in the pipe 44A and absorb displacement that may occur between the reactor core 11 and the reactor vessel 111.

[0052] According to this reactor 101, the difference in displacement between the core 11 and the reactor vessel 111 caused by the difference in thermal expansion between the support 21 and the heat transfer tube 41 can be absorbed by the expansion tubes 45A, 45B, thereby reducing the thermal stress occurring in the core 11 and the reactor vessel 111.

[0053] In the reactor 101 of the embodiment, the piping 44A is provided in an inlet manifold 43A to which one end of the heat transfer tube 41 penetrating the reactor core 11 is connected, the outlet manifold 43B is fixed to the reactor vessel 111 so that the inlet manifold 43A is supported movably relative to the reactor vessel 111, and the expansion tubes 45A, 45B are interposed in the piping 44A provided in the inlet manifold 43A.

[0054] According to this reactor 101, a displacement difference between the core 11 and the reactor vessel 111 is intentionally generated in the inlet manifold 43A, and expansion pipes 45A, 45B are interposed in the piping 44A provided in this inlet manifold 43A, thereby preferably achieving the effect of reducing thermal stresses occurring in the core 11 and the reactor vessel 111. Alternatively, the inlet manifold 43A may be fixed to the reactor vessel 111, the outlet manifold 43B may be supported movably with respect to the reactor vessel 111, and the expansion pipes 45A, 45B may be interposed in the piping 44B provided in the outlet manifold 43B and arranged inside the reactor vessel 111.

[0055] In the nuclear reactor 101 of the embodiment, the gap material 42 is made of any one of copper, boron nitride, solid lubricant paste, and carbon nanotubes.

[0056] According to this reactor 101, by applying the above-mentioned materials, the support body 21 and the heat transfer tube 41 are closely attached to each other, ensuring heat transfer performance through solid-state thermal conduction, and the effect of reducing stress caused by the difference in thermal expansion between the support body 21 and the heat transfer tube 41 can be advantageously obtained.

[0057] In the nuclear reactor 101 of the embodiment, the gap material 42 is made of powdered graphite.

[0058] The powdered graphite may be artificially produced, but in the present embodiment, flaky graphite, which is natural graphite (lithic graphite) mined from mines, is used. The flaky graphite has, for example, FC of 60% or more and 98% or less. FC is gray cast iron and contains graphite crystallized in flakes.

[0059] In this reactor 101, when powdered graphite is used as the gap filler 42, the gap filler 42 can be easily disposed between the support body 21 and the heat transfer tube 41, and the adhesion between the support body 21 and the heat transfer tube 41 can be improved. Therefore, this reactor 101 can ensure heat transfer performance through solid heat conduction and preferably obtain the effect of reducing stress caused by the difference in thermal expansion between the support body 21 and the heat transfer tube 41. Furthermore, in this reactor 101, when flaky graphite is used as the powdered graphite, the anisotropic shape of the graphite allows it to fit between the support body 21 and the heat transfer tube 41, preventing it from falling out of the gap. Furthermore, in this reactor 101, when flaky graphite is used as the powdered graphite, it is easy to obtain and the manufacturing cost can be reduced.

[0060] In the nuclear reactor 101 of the embodiment, the support 21 is made of graphite or graphene.

[0061] According to this reactor 101, the heat conduction effect due to fixed heat conduction can be suitably obtained.

[0062] In the above-described reactor 101, even if the axial direction is arranged along the horizontal direction, the same effect can be obtained by the same configuration.

[0063] The present disclosure includes the following inventions. [Invention 1] a reactor core including nuclear fuel and a support that conducts heat from the nuclear fuel; a heat transfer tube inserted into a hole formed in the support; a gap material that is filled between the support body and the heat transfer tube in the hole, absorbs a thermal expansion difference therebetween, and has heat transfer performance; Including, nuclear reactors. [Invention 2] a reactor vessel containing the reactor core; a piping that is disposed inside the reactor vessel and is connected to the heat transfer tube; an expansion pipe interposed in the piping to absorb displacement that may occur between the reactor core and the reactor vessel; The nuclear reactor according to claim 1, further comprising: [Invention 3] The gap material is made of any one of copper, boron nitride, solid lubricant paste, and carbon nanotubes. 3. The nuclear reactor according to claim 1 or 2. [Invention 4] The gap material is made of powdered graphite. 3. The nuclear reactor according to claim 1 or 2. [Invention 5] The support is made of graphite or graphene. 5. A nuclear reactor according to any one of claims 1 to 4. [Invention 6] the piping is provided in an inlet manifold to which one end of the heat transfer tube passing through the core is connected and an outlet manifold to which the other end is connected, one of the inlet manifold and the outlet manifold is fixed to the reactor vessel, and the other is supported movably relative to the reactor vessel; The expansion pipe is interposed in the piping provided in the manifold that is movable relative to the reactor vessel. A nuclear reactor according to claim 2. [Explanation of symbols]

[0064] 11 Reactor Core 21 Support 21b Hole 22 Nuclear fuel 41 Heat transfer tube 42 Gap material 43A Inlet Manifold 43B Outlet manifold 44A Inlet piping (piping) 44B Outlet piping (piping) 45A,45B Telescopic tube 101 Nuclear reactor 111 Reactor Vessel

Claims

1. a core including nuclear fuel and a support that conducts heat from the nuclear fuel; a heat transfer tube inserted into a hole formed in the support; a gap material that is filled between the support body and the heat transfer tube in the hole, absorbs a thermal expansion difference therebetween, and has heat transfer performance; Including, nuclear reactors.

2. a reactor vessel containing the reactor core; a piping that is disposed inside the reactor vessel and is connected to the heat transfer tube; an expansion pipe interposed in the piping to absorb displacement that may occur between the reactor core and the reactor vessel; 10. The nuclear reactor of claim 1 further comprising:

3. The gap material is made of any one of copper, boron nitride, solid lubricant paste, and carbon nanotubes.

10. The nuclear reactor of claim 1.

4. The gap material is made of powdered graphite.

10. The nuclear reactor of claim 1.

5. The support is made of graphite or graphene.

10. The nuclear reactor of claim 1.

6. the piping is provided in an inlet manifold to which one end of the heat transfer tube passing through the core is connected and an outlet manifold to which the other end is connected, one of the inlet manifold and the outlet manifold is fixed to the reactor vessel, and the other is supported movably relative to the reactor vessel; The expansion pipe is interposed in the piping provided in the manifold that is movable relative to the reactor vessel.

3. The nuclear reactor of claim 2.

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