Reactor core structure capable of controlling assembly clearance and manufacturing method thereof

Abstract

The invention provides a reactor core structure capable of controlling an assembly clearance and a manufacturing method thereof. The reactor core structure comprises a reactor core heat management element and a filling material; wherein the base body is provided with a plurality of assembly holes; the reactor core heat management element comprises a fuel rod or a heat pipe; the reactor core heat management element is assembled in the assembly hole of the base body; the filling material is filled in an assembly gap between the reactor core heat management element and the assembly hole; and the filling material is a shape memory alloy. The reactor core structure can improve the safety margin of the heat pipe reactor.

Description

Technical Field

[0001] The present invention relates to a heat pipe reactor, and in particular to a core structure with controllable assembly clearance and a manufacturing method thereof. Background Art

[0002] A heat pipe reactor is a new type of solid-state reactor that uses heat pipes to conduct the heat generated by the core to the secondary loop of the reactor or a thermoelectric conversion device. The heat pipe reactor uses a solid core, which consists of a metal matrix with round holes and fuel rods or heat pipes inserted into the metal matrix. The metal matrix is the working medium for heat transfer between the fuel rods and the heat pipes. When the reactor operates, heat is generated from the fuel rods and transferred to the heat pipes through the matrix, and the heat pipes transfer the heat to the thermoelectric conversion system to complete the conversion of thermoelectric energy to electrical energy.

[0003] However, since the fuel rods and the heat pipes need to be assembled into the solid matrix in sequence, there are inevitably assembly clearances between the fuel rods and the matrix, and between the heat pipes and the matrix, resulting in a large gap thermal resistance between the fuel rods and the matrix, and between the heat pipes and the matrix. The existence of the gap thermal resistance will cause a large temperature difference between the fuel rods and the heat pipes, thereby reducing the safety margin of the reactor. Summary of the Invention

[0004] The purpose of the present invention is to provide a core structure with controllable assembly clearance and a manufacturing method thereof, which can improve the safety margin of the heat pipe reactor.

[0005] One aspect of the present invention provides a core structure with controllable assembly clearance, including a matrix, a core heat management element, and a filling material; wherein, the matrix is provided with a plurality of assembly holes; the core heat management element includes a fuel rod or a heat pipe; the core heat management element is assembled in the assembly holes of the matrix; the filling material fills the assembly clearance between the core heat management element and the assembly holes; the filling material is a shape memory alloy.

[0006] In one embodiment, the shape memory alloy is attached to the surface of the core heat management element; the shape memory alloy can undergo shape recovery at the memory recovery temperature, and the radial thickness of the shape memory alloy at the memory recovery temperature is greater than the radial thickness at room temperature.

[0007] In one embodiment, the memory recovery temperature of the shape memory alloy is greater than room temperature and less than 800 °C.

[0008] In one embodiment, the shape memory alloy is a titanium-based shape memory alloy, a copper-based shape memory alloy, or an iron-based shape memory alloy.

[0009] In one embodiment, the shape memory alloy is serrated at room temperature; or the shape memory alloy includes a plurality of annular structures arranged at intervals at room temperature, and the annular structures are arranged along the circumferential direction of the core heat management element; or the shape memory alloy is helical at room temperature; or the shape memory alloy includes a plurality of raised structures arranged at intervals at room temperature, and the raised structures are arranged along the axial direction of the core heat management element.

[0010] Another aspect of the present invention provides a manufacturing method of a core structure with controllable assembly clearance, and the core structure is the core structure described in any one of the above embodiments; the manufacturing method includes: attaching a shape memory alloy to the surface of the core heat management element; assembling the core heat management element with the attached shape memory alloy into the assembly hole of the matrix.

[0011] In one embodiment, the attaching of the shape memory alloy to the surface of the core heat management element includes: depositing and forming a shape memory alloy on the surface of the core heat management element by electroplating.

[0012] In one embodiment, the attaching of the shape memory alloy to the surface of the core heat management element includes: attaching the shape memory alloy to the surface of the core heat management element by sintering.

[0013] In one embodiment, the attaching of the shape memory alloy to the surface of the core heat management element includes: depositing and forming a shape memory alloy on the surface of the core heat management element by chemical vapor deposition.

[0014] In one embodiment, the attaching of the shape memory alloy to the surface of the core heat management element includes: welding the shape memory alloy to the surface of the core heat management element; or attaching the shape memory alloy to the surface of the core heat management element by thermal spraying; or coating the shape memory alloy on the surface of the core heat management element.

[0015] The core structure with controllable assembly clearance of the present invention fills the assembly clearances between the fuel rod and the matrix and between the heat pipe and the matrix with a shape memory alloy, and utilizes the shape memory effect and pseudoelasticity of the shape memory alloy to closely fit the clearances, realizing the clearance filling function. It can reduce the assembly clearances between the heat pipe and the fuel rod and the matrix during the assembly process, effectively increase the contact areas between the fuel rod and the matrix, and between the heat pipe and the matrix, reduce the clearance thermal resistance, thereby effectively reducing the temperature difference between the core matrix and the heat pipe, improving the safety margin of the reactor, and having a simple structure. It can be carried out in a normal temperature and pressure environment, and will not increase the additional core structure, nor require additional heating or welding processes, facilitating the core assembly. Description of the Drawings

[0016] The above and other features, properties, and advantages of the present invention will become more apparent from the following description in conjunction with the drawings and embodiments, where:

[0017] Figure 1 is a schematic diagram of the core structure of the heat pipe reactor before improvement;

[0018] Figure 2 is a schematic diagram of the core heat management element attached with shape memory alloy at normal temperature according to an embodiment of the core structure of the present invention;

[0019] Figure 3 is Figure 2 a schematic diagram of the shape memory alloy shown at the memory recovery temperature;

[0020] Figure 4 is a schematic flow diagram of a manufacturing method of the core structure according to an embodiment of the present invention. Detailed Embodiments

[0021] A heat pipe reactor is a new type of solid-state reactor that uses heat pipes to conduct the heat generated in the core to the secondary loop of the reactor or a thermoelectric conversion device.

[0022] Figure 1 Shows the core structure of an existing heat pipe reactor. The heat pipe reactor uses a solid core, which consists of a metal matrix 10 with round holes and a core heat management element 20 inserted into the matrix 10. Among them, the core heat management element includes a fuel rod 22 and a heat pipe 21. The fuel rod 22 and the heat pipe 21 need to be assembled in the matrix 10 in sequence.

[0023] The matrix 10 is a working medium for transferring heat between the fuel rod 22 and the heat pipe 21. During reactor operation, heat is generated from the fuel rod 22 and transferred to the heat pipe 21 through the matrix 10, and the heat pipe 21 transfers the heat to the thermoelectric conversion system to complete the conversion of thermoelectric energy to electrical energy.

[0024] However, there is inevitably an assembly gap 120 between the fuel rod 22, the matrix 10, and the heat pipe 21, resulting in a large gap thermal resistance among the three. The existence of the gap thermal resistance will cause a large temperature difference between the fuel rod 22 and the heat pipe 21, thereby reducing the safety margin of the reactor.

[0025] To reduce the gap thermal resistance, the prior art before improvement includes: filling powder between the fuel rod 22 and the matrix 10, and between the fuel rod 22 and the heat pipe 21 during assembly; filling liquid thermal conductive material between the fuel rod 22 and the matrix 10, and between the fuel rod 22 and the heat pipe 21; closely fitting the heat pipe 21 and the matrix 10. The above three methods all reduce the safety margin of the reactor by minimizing the assembly gap 120 as much as possible.

[0026] The above-mentioned technology before improvement can reduce the assembly gap 120 to 100 μm. To measure the gap thermal resistance in this state, an electric heating rod is inserted into the center of the heat pipe 21, and electricity is supplied to heat the base body 10 to 800 °C. In this state, the temperatures of the heat pipe 21 and the base body 10 are measured. It is found that when the temperature of the base body 10 is 800 °C, the temperature of the heat pipe 21 can reach 1226.7 °C, that is, there is a temperature difference of about 426.7 °C between the heat pipe 21 and the base body 10 due to the existence of the gap thermal resistance.

[0027] However, in the above method, since some metal powders and graphite powders are flammable and explosive, using powder filling itself has certain risks; at the same time, the filling process mostly relies on gravity and the fluidity of the powder itself, and it is difficult to ensure uniform powder distribution. Although using liquid heat-conducting materials can effectively reduce the gap thermal resistance between the base body 10 and the heat pipe 21, due to the introduction of high-temperature metal liquids, the core needs to be hermetically sealed as a whole, and the assembly process needs to be carried out under high-temperature conditions, and the assembly process has considerable risks and complexity. Although the method of reducing the assembly gap 120 can effectively reduce the thermal resistance between the base body 10 and the heat pipe 21, too small a gap will cause assembly difficulties, and the outer walls of the fuel rod 22, the outer wall of the heat pipe 21, and the inner wall of the base body 10 are also prone to surface damage during the assembly process, which will have an adverse impact on interface heat transfer.

[0028] Now, reference will be made in detail to the embodiments of the present invention, one or more examples of which are shown in the drawings. Each example is provided to explain the present invention, not to limit the present invention. In fact, it is obvious to those skilled in the art that various modifications and changes can be made to the present invention without departing from the scope or spirit of the present invention. For example, features shown or described as part of one embodiment can be used with another embodiment to produce yet another embodiment. Therefore, the present invention is intended to cover these modifications and changes that fall within the scope of the appended claims and their equivalents.

[0029] As used herein, the term "axial direction" is the central axis of the fuel rod 22 or the heat pipe 21 or the direction parallel to the central axis of the fuel rod 22 or the heat pipe 21, the "radial direction" is the direction perpendicular to the "axial direction", and the term "circumferential direction" is the direction around the "axial direction".

[0030] The safety margin refers to a certain margin reserved in the design parameters when designing a reactor to ensure its safe operation under various possible operating conditions.

[0031] Figure 2 and Figure 3 shows the structures of an embodiment of the core heat management element 20 of the core structure of the present invention at different temperatures respectively. Combining Figure 1 、 Figure 2 and Figure 3, the core structure of the present invention includes a matrix 10, core heat management elements 20, and a filling material. Among them, the matrix 10 is provided with a plurality of assembly holes 110. The core heat management elements 20 include heat pipes 21 or fuel rods 22. The core heat management elements 20 are assembled in the assembly holes 110 of the matrix 10. The present invention does not limit the specific assembly positions of the fuel rods 22 and the heat pipes 21, and they can be assembled according to actual sequence requirements.

[0032] The filling material is filled in the assembly gap 120 between the core heat management elements 20 and the assembly holes 110. The filling material is a shape memory alloy 400.

[0033] By filling the shape memory alloy 400 in the assembly gap 120 between the fuel rod 22 and the matrix 10 or the assembly gap 120 between the heat pipe 21 and the matrix 10, the core structure of the present invention utilizes the shape memory effect and pseudoelasticity of the shape memory alloy 400 to closely fit the gap, realizing the gap filling function, which can reduce the assembly gap 120 between the heat pipe 21 and the fuel rod 22 and the matrix 10 during the assembly process, effectively increasing the contact area between the fuel rod 22 and the matrix 10, and between the heat pipe 21 and the matrix 10, reducing the gap thermal resistance, thereby effectively reducing the temperature difference between the core matrix 10 and the heat pipe 21 and improving the safety margin of the reactor.

[0034] At the same time, the overall structure of the core structure of the present invention is simple, can be carried out under normal temperature and pressure environments, will not increase additional core structures, and does not require additional heating or welding processes, facilitating core assembly.

[0035] Shape Memory Alloy (SMA) is an alloy material with special memory function, and its basic principle is based on thermoelastic martensitic transformation. At a certain temperature, the crystal structure of the alloy will undergo a phase change. For example, at a lower temperature, the alloy presents a martensite phase, and its crystal structure is relatively distorted; when the temperature rises to a certain specific transformation temperature, the alloy will transform into an austenite phase, and the crystal structure returns to a regular state, thus enabling the alloy to return to the pre-set shape.

[0036] The present invention utilizes the shape memory effect and pseudoelasticity of the shape memory alloy 400. At a lower temperature (such as room temperature), the shape memory alloy 400 presents a smaller radial dimension. As the temperature rises to the parent phase transformation start temperature, the shape memory alloy 400 undergoes shape recovery, manifested as an increase in radial dimension, and closely fits the gap, realizing the gap filling function.

[0037] In one embodiment, the shape memory alloy 400 is attached to the core heat management element 20 such that the shape memory alloy 400 is pre-mounted on the outer surface of the fuel rod 22 and / or the heat pipe 21. After the mounting of the shape memory alloy 400 is completed, the fuel rod 22 and the shape memory alloy 400, and the heat pipe 21 and the shape memory alloy 400 are assembled as a whole.

[0038] As Figure 2 and Figure 3 shown, the shape memory alloy 400 is attached to the surface (i.e., the outer peripheral surface) of the core heat management element 20. The axial height at which the shape memory alloy 400 is attached is not less than the axial height of the assembly hole 110 to ensure the filling of the assembly gap 120. Preferably, the outer peripheral surface of the core heat management element 20 is entirely attached with the shape memory alloy 400, that is, the entire section of the core heat management element 20 is mounted with the shape memory alloy 400.

[0039] According to the characteristics of the shape memory alloy 400, the shape memory alloy 400 can undergo shape recovery at the memory recovery temperature, and the radial thickness of the shape memory alloy 400 at the memory recovery temperature is greater than the radial thickness at room temperature. Herein, room temperature refers to the temperature range of 15°C to 30°C.

[0040] Figure 2 shows the morphology of the shape memory alloy 400 at room temperature, Figure 3 shows the morphology of the shape memory alloy 400 at the memory recovery temperature. The shape memory alloy 400 has a smaller radial size at room temperature to facilitate the assembly of the core heat management element 20, as Figure 2 shown; when heated to the memory recovery temperature, the shape memory alloy 400 undergoes shape recovery, has a larger radial size than at room temperature, and closely adheres to the surface of the core heat management element 20, so that the assembly gap 120 can be completely filled, as Figure 3 shown.

[0041] During the assembly stage at room temperature, the shape memory alloy 400 can reserve a larger gap size to avoid wear or volume change of the gap filling material during the assembly process; at high temperature, the shape memory alloy 400 can tightly fill the assembly gap 120, reducing the gap thermal resistance between the heat pipe 21 and the matrix 10, and between the fuel rod 22 and the matrix 10 in the operating state of the heat pipe reactor, and can simultaneously meet the requirements of easy assembly and enhanced gap heat transfer. When the temperature rises to the memory recovery temperature, the shape memory alloy 400 will undergo recovery, the radial size increases and fills the assembly gaps 120 between the fuel rod 22 and the matrix 10, and between the heat pipe 21 and the matrix 10.

[0042] Meanwhile, the shape memory alloy 400 itself has good heat transfer performance, that is, a high effective thermal conductivity, and has strong heat conduction ability at high temperatures, enabling the heat of the core matrix 10 to be effectively transferred to the heat pipe 21.

[0043] In a specific embodiment, at room temperature, the shape memory alloy 400 can be serrated, as Figure 2 shown; the shape memory alloy 400 can also include a plurality of annular structures arranged at intervals, and the annular structures are arranged along the circumferential direction of the core heat management element 20; the shape memory alloy 400 can also be helical; the shape memory alloy 400 can also be arranged in a groove, that is, it includes a plurality of protruding structures (which can also be understood as strips) arranged at intervals, and the protruding structures are arranged along the axial direction of the fuel rod 22 or the heat pipe 21; the shape memory alloy 400 can also be other irregular shapes. The common feature of the above various shapes is that the shape memory alloy 400 has a smaller radial dimension at room temperature for easy assembly.

[0044] Before installing the shape memory alloy 400, it needs to be pre-treated so that it has a larger radial structure at the memory recovery temperature and a smaller radial dimension (such as serrated) at room temperature.

[0045] The memory recovery temperature of the shape memory alloy 400 of the present invention is a high temperature, that is, the memory recovery temperature of the shape memory alloy 400 is greater than room temperature and less than 800 °C. Among them, 800 °C is the actual operating temperature of the heat pipe reactor, and the memory recovery temperature of the shape memory alloy 400 should be lower than the above actual operating temperature of the heat pipe reactor and higher than room temperature. Considering the deformation rate of the shape memory alloy 400, the memory recovery temperature of the shape memory alloy 400 is preferably 60 - 500 °C.

[0046] Optionally, the shape memory alloy 400 is a titanium-based shape memory alloy 400 or a copper-based shape memory alloy 400 or an iron-based shape memory alloy 400. The above three shape memory alloys 400 all have appropriate memory recovery temperatures and excellent thermal conductivities (that is, high thermal conductivities).

[0047] Among them, the nickel-titanium-based shape memory alloy 400 includes but is not limited to Ni-Ti-Cu, Ni-Ti-Fe, Ni-Ti-Nb. The copper-based shape memory alloy 400 includes but is not limited to Cu-Zn, Cu-Zn-Al, Cu-Zn-Sn. The iron-based shape memory alloy 400 includes but is not limited to Fe-Pt, Fe-Mn-Si, Fe-Ni-Co-Ti. Of course, other types of shape memory alloys 400 that satisfy the memory recovery temperature greater than room temperature and less than 800 °C can be used as the shape memory alloy 400 of the present invention to fill the assembly gap 120, and the present invention makes no limitation.

[0048] Figure 4The manufacturing method of the core structure of the present invention is shown. As Figure 4 shown, the manufacturing method of the present invention includes steps S100 to S200:

[0049] In step S100, the shape memory alloy 400 is attached to the surface of the core heat management element 20.

[0050] In step S200, the core heat management element 20 attached with the shape memory alloy 400 is assembled into the assembly hole 110 of the base body 10.

[0051] The shape memory alloy 400 can be attached to the surface of the core heat management element 20 by one of the methods of electroplating, sintering, vapor deposition, welding, thermal spraying, and coating described in the above embodiments.

[0052] Specifically, in the attachment method of electroplating, first, the surface of the core heat management element 20 is treated by methods such as grinding and pickling to achieve roughening of the core heat management element 20; after roughening is completed, it is activated. After activation, with the shape memory alloy as the anode and the core heat management element 20 as the cathode, by adjusting the electroplating current, voltage, etc., the shape memory alloy ions migrate to the surface of the core heat management element 20 under the action of the electric field and deposit to form a thin film. After electroplating is completed, the surface of the core heat management element 20 is cleaned to remove the electroplating solution on the surface of the core heat management element 20.

[0053] In the attachment method of sintering, first, a layer of sintering aid is coated on the surface of the core heat management element 20; at room temperature, the shape memory alloy 400 is attached to the surface of the core heat management element 20. Then, sintering is carried out at an appropriate temperature and time so that the sintering aid of the core heat management element 20 is cured and the shape memory alloy 400 is firmly attached to the surface of the core heat management element 20. Among them, the selection of the sintering temperature and time is determined according to the properties of the sintering aid.

[0054] Vapor deposition includes physical vapor deposition method and chemical vapor deposition method. In the attachment method of vapor deposition of the present invention, in the physical vapor deposition method, an electron beam heating or other heating method is used to turn the metal to be deposited into a gas state, and then the gaseous metal is deposited on the core heat management element 20 by condensation. Chemical vapor deposition is to put the core heat management element 20 into a plating solution for electroless plating to obtain a shape memory alloy layer evenly attached to the surface of the core heat management element 20.

[0055] The attachment methods of the shape memory alloy 400 can also include welding, thermal spraying, coating, and other methods, which can better cover the outer surface of the core heat management element 20 and avoid affecting the gap heat transfer between the core heat management element 20 and the base body 10 due to uneven distribution of filling materials and other situations.

[0056] It should be noted that, in order to confirm the improvement effect of the present invention on the gap heat transfer performance, in the embodiments of the present invention, the temperature of the core heat management element 20 was measured in the same manner as the foregoing method, that is, an electric heating rod was inserted into the center of the core heat management element 20, and the substrate 10 was heated to 800 °C by energization, and the temperatures of the core heat management element 20 and the substrate 10 were measured in this state.

[0057] The following will elaborate in detail on the core structure of the present invention and its manufacturing method in combination with three specific embodiments to illustrate the technical effects achieved by the core structure of the present invention:

[0058] In a specific embodiment, the shape memory alloy 400 is selected as a nickel-titanium-based shape memory alloy 400, specifically Ti-Ni, and its memory recovery temperature is adjusted to 60 °C in advance by heat treatment.

[0059] The strip-shaped shape memory alloy 400 is attached to the surface of the core heat management element 20 by welding, and the structure is as Figure 2 shown.

[0060] The core heat management element 20 processed by the above process can be freely assembled by being inserted into the substrate 10 under the conventional process. When the temperature rises, the shape memory alloy 400 will return to the shape close to the surface of the core heat management element 20, improving the gap thermal resistance. After the temperature of the substrate 10 is raised to 800 °C by using an electric heating rod, the temperature of the core heat management element 20 is measured. The test results show that the temperature of the core heat management element 20 is 913.4 °C. In this specific embodiment, the gap thermal resistance between the core heat management element 20 and the substrate 10 is significantly improved, and the temperature difference caused by the gap thermal resistance between the two is reduced from 426.7 °C to 113.4 °C.

[0061] In another specific embodiment, the shape memory alloy 400 is selected as a copper-zinc-based shape memory alloy 400, specifically Cu-Zn, and its memory recovery temperature is adjusted to 100 - 120 °C in advance through appropriate composition design and heat treatment process.

[0062] The strip-shaped shape memory alloy 400 is carried on the core heat management element 20 by chemical vapor deposition, and the carried structure is as Figure 2 shown.

[0063] The core thermal management component 20 processed by the above process can be freely assembled by inserting it into the matrix 10 under conventional processes. When the temperature rises, the shape memory alloy 400 will return to the shape that closely adheres to the surface of the heat pipe 21, improving the gap thermal resistance. After using an electric heating rod to raise the temperature of the matrix 10 to 800 °C, the temperature of the core thermal management component 20 was measured. The test results show that the temperature of the core thermal management component 20 is 908.3 °C. In this specific embodiment, the gap thermal resistance between the core thermal management component 20 and the matrix 10 has been significantly improved, and the temperature difference caused by the gap thermal resistance between the two has been reduced from 426.7 °C to 108.3 °C.

[0064] In another specific embodiment, the shape memory alloy 400 is selected as a copper-zinc-aluminum-based shape memory alloy 400, specifically a Cu-Zn-Al alloy. In the initial stage, Cu, Zn, and Al are pre-deposited on the surface of the core thermal management component 20 by magnetron sputtering in a specific ratio.

[0065] After the deposition is completed, the laser powder bed melting technology is used to regulate the structure of the surface of the pre-deposited alloy, and a shape memory alloy coating with a memory recovery temperature of 120 °C is prepared.

[0066] The core thermal management component 20 processed by the above process can be freely assembled by inserting it into the matrix 10 under conventional processes. When the temperature rises, the shape memory alloy 400 coating will undergo radial volume expansion due to shape recovery and closely adhere to the surface of the core thermal management component 20, thereby improving the gap thermal resistance. After using an electric heating rod to raise the temperature of the matrix 10 to 800 °C, the temperature of the core thermal management component 20 was measured. The test results show that the temperature of the core thermal management component 20 is 933.6 °C. In this specific embodiment, the gap thermal resistance between the core thermal management component 20 and the matrix 10 has been significantly improved, and the temperature difference caused by the gap thermal resistance between the two has been reduced from 426.7 °C to 133.6 °C.

[0067] The core thermal management component 20 of the present invention equipped with the shape memory alloy 400 can be assembled with the matrix 10 through a conventional assembly process. The assembly process is simple; after the assembly is completed, as the reactor power increases, the surface temperature of the core thermal management component 20 rises accordingly. When the temperature is higher than the memory recovery temperature of the shape memory alloy 400, the radial dimension of the shape memory alloy 400 increases, and then the gap between it and the matrix 10 is filled.

[0068] Since the assembly of the core heat management element 20 needs to be carried out on site, based on effectively improving the filling quality and reducing the gap thermal resistance, the overall structure of the core structure of the present invention is simple enough to be carried out under normal temperature and pressure, without changing the overall core structure, without adding additional core structures and additional processing techniques, without additional atmosphere protection, without additional heating or welding processes, and can effectively reduce the gap thermal resistance between the fuel rod 22 and the matrix 10, and between the heat pipe 21 and the matrix 10, which is quite necessary.

[0069] Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and decoration made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A core structure with controllable assembly gap, characterized in that: It includes a matrix, a core thermal management element and a filling material; wherein, The base body is provided with a plurality of assembly holes; The core thermal management element includes a fuel rod or a heat pipe; The core thermal management element is assembled in the assembly hole of the base body; The filling material is filled in the assembly gap between the core thermal management element and the assembly hole; The filling material is a shape memory alloy.

2. The core structure according to claim 1, characterized in that: The shape memory alloy is attached to the surface of the core thermal management element; The shape memory alloy can recover its shape at a memory recovery temperature, and a radial thickness of the shape memory alloy at the memory recovery temperature is greater than a radial thickness at room temperature.

3. The core structure according to claim 2, characterized in that: The memory recovery temperature of the shape memory alloy is greater than room temperature and less than 800°C.

4. The core structure according to claim 2, characterized in that: The shape memory alloy is a titanium-based shape memory alloy, a copper-based shape memory alloy, or an iron-based shape memory alloy.

5. The core structure according to any one of claims 2 to 4, characterized in that: The shape memory alloy is in a serrated shape at room temperature; or The shape memory alloy comprises a plurality of annular structures arranged at intervals at room temperature, and the annular structures are arranged along the circumference of the core thermal management element; or The shape memory alloy is in a spiral shape at room temperature; or The shape memory alloy comprises a plurality of spaced-apart convex structures at room temperature, and the convex structures are arranged along the axial direction of the core thermal management element.

6. A method for manufacturing a core structure with controllable assembly gap, characterized in that: The core structure is a core structure with controllable assembly gap according to any one of claims 2 to 5; The manufacturing method comprises: attaching shape memory alloys to the surface of core thermal management components; The core thermal management element with the shape memory alloy attached thereto is assembled in the assembly hole of the substrate.

7. The manufacturing method according to claim 6, characterized in that: The step of attaching the shape memory alloy to the surface of the core thermal management element comprises: The shape memory alloy is deposited on the surface of the core thermal management element by electrodeposition.

8. The manufacturing method according to claim 6, characterized in that: The step of attaching the shape memory alloy to the surface of the core thermal management element comprises: The shape memory alloy is attached to the surface of the core thermal management element by sintering.

9. The manufacturing method according to claim 6, characterized in that: The step of attaching the shape memory alloy to the surface of the core thermal management element comprises: The shape memory alloy is deposited on the surface of the core thermal management element by vapor deposition.

10. The manufacturing method according to claim 6, characterized in that: The step of attaching the shape memory alloy to the surface of the core thermal management element comprises: Welding the shape memory alloy to the surface of the core thermal management element; or Adhere the shape memory alloy to the surface of the core thermal management element by thermal spraying; or The shape memory alloy is coated on the surface of the core thermal management element.

Images