Reactivity adjusting device suitable for space nuclear reactor and space nuclear reactor

Abstract

The invention relates to the technical field of nuclear reactors, in particular to a reactivity adjusting device suitable for a space nuclear reactor and the space nuclear reactor. The reactivity adjusting device can comprise a heat transfer part and a reactivity adjusting part. The heat transfer piece is used for transferring heat of the reactor core to the outside of the reactor core. The reactivity adjusting piece forms a sealing cavity filled with neutron absorption fluid, the sealing cavity comprises a first cavity arranged outside the reactor core and a second cavity which is arranged in the reactor core and is in fluid communication with the first cavity, and the first cavity is in heat conduction connection with the heat transfer piece outside the reactor core; the temperature of the neutron absorption fluid in the first cavity correspondingly changes along with the temperature of the reactor core, and the content of the neutron absorption fluid in the second cavity changes due to the thermal expansion and cold contraction effect, so that the reactivity of the reactor core is adjusted. According to the reactivity adjusting device provided by the embodiment of the invention, the space nuclear power supply can realize autonomous operation without active intervention of any control system.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of nuclear reactors, and in particular to a reactivity regulating device suitable for a space nuclear reactor and a space nuclear reactor. Background Art

[0002] This section of content merely provides background information related to the present application and does not necessarily constitute prior art.

[0003] Space nuclear reactors are used in the field of aerospace. After they are put into operation, the reactivity will continue to decrease due to the continuous deepening of burnup. Usually, the control system is used to compensate for the reactivity by adjusting the control drum, sliding reflector and other control mechanisms. For example, as the core burnup deepens, the control system can adjust the rotation angle of the control drum so that the absorber of the control drum gradually turns to the outside of the core to introduce reactivity; or adjust the axial position of the sliding reflector relative to the core active area to increase the reactivity of the space nuclear reactor and maintain the normal operation of the space nuclear reactor. In both schemes, the control system needs to participate in the control of the space nuclear reactor throughout the process, resulting in the over-reliance of the operating life of the space nuclear reactor on the reliability of the control system, poor passive safety, and difficulty in achieving autonomous operation. Summary of the invention

[0004] A brief overview of the present application is provided below in order to provide a basic understanding of certain aspects of the present application. It should be understood that this overview is not an exhaustive overview of the present application. It is not intended to identify the key or important parts of the present application, nor is it intended to limit the scope of the present application. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0005] In view of the above technical problems, the embodiments of the present application provide a reactivity regulating device suitable for a space nuclear reactor and a space nuclear reactor.

[0006] In the first aspect, an embodiment of the present application provides a reactivity regulating device suitable for a space nuclear reactor. The reactivity regulating device may include: a heat transfer member and a reactivity regulating member. The heat transfer member is used to transfer the heat of the core to the outside of the core. The reactivity regulating member forms a sealed cavity filled with a neutron absorbing fluid, the sealed cavity includes a first cavity arranged outside the core and a second cavity arranged inside the core and connected to the first cavity fluid, and the reactivity regulating member is thermally connected to the heat transfer member outside the core, so that the temperature of the neutron absorbing fluid in the first cavity changes accordingly with the core temperature, and the neutron absorbing fluid content in the second cavity changes due to the thermal expansion and contraction effect, thereby adjusting the reactivity of the core.

[0007] In the embodiments of the present application, when the core temperature changes, the temperature of the heat transfer element will change, and the temperature change of the heat transfer element can directly cause the temperature change of the neutron absorbing fluid in the first cavity, thereby causing the volume of the neutron absorbing fluid in the first cavity to change due to thermal expansion and contraction, thereby changing the content of the neutron absorbing fluid in the second cavity and changing the reactivity. The embodiments of the present application utilize the thermal expansion and contraction effect of the neutron absorbing fluid, and the burnup reactivity loss can be compensated by a small drop in the fuel temperature in the core, maintaining the critical operation of the reactor without the active intervention of any control system. Autonomous operation. Since the thermal expansion and contraction effect of the neutron absorbing fluid is utilized in the present application, it does not involve any thermal expansion and contraction or length change of any solid material, nor does it involve relative displacement between solid components. Therefore, it has higher reliability and is more suitable for long-life operation in space.

[0008] In a second aspect, an embodiment of the present application provides a space nuclear reactor, which includes: a core, a thermoelectric conversion element, and a reactivity adjustment device provided in the first aspect of the present application. The core is used to provide heat; the thermoelectric conversion element is arranged outside the core and is used to convert the heat of the core into electrical energy; the reactivity adjustment device is used to adjust the reactivity of the core.

[0009] These and other advantages of the present application will become more apparent through the following detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to further illustrate the above and other advantages and features of the present application, the specific embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. The accompanying drawings together with the following detailed description are included in this specification and form a part of this specification. Elements with the same function and structure are represented by the same reference numerals. It should be understood that these drawings only describe typical examples of the present application and should not be regarded as limiting the scope of the present application.

[0011] Figure 1 is a cross-sectional schematic diagram of a space nuclear reactor according to an embodiment of the present application;

[0012] Figure 2 The position of the liquid level in the reactivity regulator at the initial stage of reactor operation is shown;

[0013] Figure 3 It shows the position of the liquid level in the reactivity regulating member when the space nuclear reactor is running after the thermal power decreases;

[0014] Figure 4 is a schematic structural diagram of a reactive regulating member according to an embodiment of the present application;

[0015] Figure 5 yes Figure 4 A schematic cross-sectional view of the reactive regulating member shown;

[0016] Figure 6 Shows Figure 5 A filling method of the capillary structure in the reactive regulating member shown;

[0017] Figure 7 Shows Figure 5 Another way of filling the capillary structure in the reactive regulating element is shown.

[0018] It should be noted that the drawings are not necessarily drawn to scale, but are merely shown in a schematic manner that does not affect the reader's understanding.

[0019] Description of reference numerals:

[0020] 10. Core; 20. Heat transfer component; 30. Axial reflection layer; 40. Radial reflection layer; 50. Fuel; 60. Safety rod channel; 70. Reactivity adjustment component; 71. Shell; 710. First cavity; 711. Heat transfer through hole; 72. Pipe; 720. Second cavity; 721. Liquid level; 73. Capillary structure. DETAILED DESCRIPTION

[0021] Exemplary embodiments of the present application will be described below in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all features of the actual implementation are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the process of developing any such actual implementation in order to achieve the developer's specific goals, such as meeting those constraints related to the system and business, and these constraints may vary from implementation to implementation. In addition, it should be understood that although the development work may be very complex and time-consuming, it is only a routine task for those skilled in the art who benefit from the content of this application.

[0022] It is also necessary to explain here that, in order to avoid obscuring the present application due to unnecessary details, only the device structure and / or processing steps closely related to the scheme according to the present application are shown in the accompanying drawings, while other details that are not very relevant to the present application are omitted.

[0023] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in this application should have the common meanings understood by persons with ordinary skills in the field to which this application belongs.

[0024] In the description of the embodiments of the present application, “plurality” means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0025] In order to improve the autonomous operation of space nuclear reactors, that is, during the operation of space nuclear reactors, there is no need for active intervention of the control system, and the reactivity loss can be compensated by a small temperature change of the fuel. In the related art, the reactivity is usually adjusted by using the change in length of the heat pipe or bellows under the action of thermal expansion and contraction to drive the displacement of the safety rod / absorber or side reflector, that is, the reactivity is adjusted by using the change in the length of the solid parts caused by thermal expansion and contraction (such as the contraction of the bellows and the thermal expansion and contraction of the long heat pipe) and then causing the relative displacement between the solid parts.

[0026] The inventors of the present application have discovered that although the above-mentioned method of adjusting the reactivity of the reactor does not need to rely on the control system, it may have the following problems: 1) During operation, various materials (including the walls of the heat pipes and the walls of the bellows) are exposed to neutrons / photons and cosmic rays for a long time, and their material properties (such as the expansion coefficient of the walls of the heat pipes and the elastic coefficient of the walls of the bellows) may change, and the expected effect may not be achieved during actual operation; 2) When in a space vacuum environment for a long time, cold welding may occur between contacting parts, making it impossible for the parts to have relative displacement. Once the parts (such as the safety rod and the safety rod guide tube, the side reflection layer and the core container, etc.) come into contact, their relative displacement may not be achieved.

[0027] In response to the above technical problems, the embodiments of the present application provide a safer, more reliable space nuclear reactor capable of operating autonomously.

[0028] See also Figure 1 , Figure 1 1 is a cross-sectional schematic diagram of a space nuclear reactor according to an embodiment of the present application. The space nuclear reactor of the embodiment of the present application may include: a core 10, a thermoelectric conversion element, and a reactivity adjustment device. The core 10 is used to provide heat. The thermoelectric conversion element is arranged outside the core 10 and is used to convert the heat of the core 10 into electrical energy. The reactivity adjustment device is used to adjust the reactivity of the core 10.

[0029] The reactivity adjustment device may include a heat transfer member 20 and a reactivity adjustment member 70. The heat transfer member 20 is used to transfer the heat of the core 10 to the outside of the core 10. The reactivity adjustment member 70 forms a sealed cavity filled with a neutron absorbing fluid, the sealed cavity includes a first cavity 710 disposed outside the core 10 and a second cavity 720 disposed in the core 10 and in fluid communication with the first cavity 710, the first cavity 710 is thermally connected to the heat transfer member 20, so that the temperature of the neutron absorbing fluid in the first cavity 710 changes accordingly with the temperature of the core 10, and the neutron absorbing fluid content in the second cavity 720 changes due to the thermal expansion and contraction effect, thereby adjusting the reactivity of the core 10.

[0030] In the embodiment of the present application, when the temperature of the core 10 changes, the temperature of the heat transfer element 20 will change, and the temperature change of the heat transfer element 20 can directly cause the temperature change of the neutron absorbing fluid in the first cavity 710, thereby causing the volume of the neutron absorbing fluid in the first cavity 710 to change due to thermal expansion and contraction, thereby changing the content of the neutron absorbing fluid in the second cavity 720 and changing the reactivity. The embodiment of the present application utilizes the thermal expansion and contraction effect of the neutron absorbing fluid, and can compensate for the burnup reactivity loss by a small drop in the temperature of the fuel 50 in the core 10, and maintain the critical operation of the reactor without the active intervention of any control system. Since the present application utilizes the thermal expansion and contraction effect of the neutron absorbing fluid, it does not involve any thermal expansion and contraction or length change of any solid material, nor does it involve relative displacement between solid components, so it has higher reliability and is more suitable for long-life operation in space.

[0031] Specifically, see Figure 2 and Figure 3 , Figure 2 The position of the liquid level in the reactivity regulator at the initial stage of reactor operation is shown; Figure 3 The figure shows the position of the liquid level in the reactivity regulating member when the space nuclear reactor is running after the thermal power decreases. In the early stage of the reactor operation, the liquid level 721 of the neutron absorbing fluid in the second chamber 720 is at a relatively low position, and at this time, the core 10 contains more neutron absorbing material and neutron absorbing fluid. As the burnup deepens (the consumption of the fuel 50), the reactivity will decrease, causing the thermal power of the core 10 to decrease, and then causing the temperature of the fuel 50 to decrease. The heat transfer member 20 is arranged in the fuel 50, and its temperature will also decrease as the temperature of the fuel 50 decreases. Therefore, the temperature of the heat transfer member 20 outside the core 10 will also decrease. Since the heat transfer element 20 is in thermal contact with the first cavity 710, the temperature of the neutron absorbing fluid in the first cavity 710 will also drop. The drop in the temperature of the neutron absorbing fluid will cause its volume to shrink due to the thermal expansion and contraction effect, thereby driving the neutron absorbing fluid level 721 in the second cavity 720 to move upward, which will reduce the amount of neutron absorbing fluid in the core 10, thereby introducing positive reactivity into the core 10, compensating for the fuel consumption reactivity loss, and maintaining critical operation of the core 10.

[0032] See also Figure 4 and Figure 5 , Figure 4 is a schematic structural diagram of a reactive regulating member according to an embodiment of the present application; Figure 5 yes Figure 4The cross-sectional schematic diagram of the reactivity adjustment member is shown; in some embodiments, the reactivity adjustment member 70 may include: a shell member 71 and a plurality of pipe members 72. The shell member 71 is disposed outside the core 10, and the shell member 71 forms a first cavity 710. The pipe members 72 extend from the inside of the core 10 to connect with the shell member 71, and each pipe member 72 forms a second cavity 720, and the second cavity 720 is fluidically connected with the first cavity 710 to form a sealed cavity. Among them, the heat transfer member 20 is thermally connected to the shell member 71, so that the temperature of the shell member 71 changes in the same direction as the temperature in the core 10, so that the neutron absorbing fluid in the first cavity 710 changes its volume accordingly due to thermal expansion and contraction, thereby changing the content of the neutron absorbing fluid in the second cavity 720. In such an embodiment, when the content of the neutron absorbing fluid in the second cavity 720 changes, the content of the neutron absorbing fluid in the core 10 changes, thereby adjusting the reactivity of the core 10.

[0033] During its life cycle, the reactor drives the liquid level 721 of the neutron absorbing fluid in the second chamber 720 to slowly move upward through a small and slow drop in the temperature of the fuel 50, so that the reactor maintains a critical operating state. When the reactor operates to the end of its life cycle, the liquid level 721 of the neutron absorbing fluid will rise to the outside of the fuel 50 located in the core 10.

[0034] It is easy to understand that in the embodiment of the present application, the sum of the volumes of the second chambers 720 is much smaller than the volume of the first chamber 710, and the core 10 can only affect the temperature of a small amount of neutron absorbing fluid in the tube 72, which can cause a very small volume change. The volume change of the neutron absorbing fluid mainly comes from the volume change corresponding to the larger amount of neutron absorbing fluid in the first chamber 710.

[0035] In some embodiments, the volume of the first cavity 710 may be more than 10 times the volume of the entire second cavity 720 .

[0036] In some embodiments, the shell 71 can form a heat transfer hole 711; the heat transfer element 20 is inserted into the heat transfer hole 711, and the heat transfer element 20 is thermally connected to the hole wall of the heat transfer hole 711, so as to facilitate improving the heat exchange effect between the heat transfer element 20 and the neutron absorbing fluid in the first cavity 710.

[0037] In some embodiments, the heat transfer element 20 and the heat transfer through hole 711 may be connected by welding.

[0038] In some embodiments, the heat transfer member 20 may be a heat pipe. The reactivity regulating device may include a plurality of heat pipes. Accordingly, the shell 71 may form a plurality of heat transfer through holes 711; each heat pipe extends through a corresponding heat transfer through hole 711 to be thermally connected to the thermoelectric conversion element, and the heat pipe is thermally connected to the hole wall of the heat transfer through hole 711. The heat pipe has good axial isothermal properties, and the portion extending outside the core 10 and the portion inside the core 10 have similar temperatures.

[0039] In some embodiments, the heat transfer element 20 is a sodium heat pipe.

[0040] In some embodiments, the neutron absorbing fluid may be Li-6. Li-6 has a strong neutron absorbing effect.

[0041] In some embodiments, the space nuclear reactor may be a space heat pipe reactor. In addition to the space heat pipe reactor, the reactivity adjustment device of the embodiment of the present application is also applicable to various other types of nuclear reactors, and the position and size of the reactivity adjustment member 70 can be flexibly adjusted according to the specific reactor parameter requirements.

[0042] In some embodiments, the heat transfer element 20 may be a coolant circuit, so as to transfer heat to the shell 71 by circulating a coolant in the coolant circuit.

[0043] In some embodiments, the thermoelectric conversion element is thermally connected to the heat transfer member 20. Specifically, the heat transfer member 20 extends through the heat transfer through hole 711 to be thermally connected to the thermoelectric conversion element.

[0044] In some other embodiments, the space nuclear reactor of the embodiment of the present application may further include another heat transfer component, and the thermoelectric conversion element is thermally connected to the other heat transfer component.

[0045] In some embodiments, the second chamber 720 may also be filled with an inert gas, and the inert gas is located below the neutron absorbing fluid. In other words, the space below the liquid level 721 is filled with inert gas. In such an embodiment, when the content of the neutron absorbing fluid in the second chamber 720 changes, the inert gas can facilitate the adjustment of the space occupied by the neutron absorbing fluid in the second chamber 720.

[0046] See also Figure 6 and Figure 7 , Figure 6 Shows Figure 5 A filling method of the capillary structure in the reactive regulating member shown, Figure 7 Shows Figure 5 Another filling method of the capillary structure in the reactivity adjustment member shown. In some embodiments, the first cavity 710 may be filled with a capillary structure 73 so that the neutron absorbing fluid is retained in the first cavity 710 under the action of its surface tension and the capillary structure 73, and the neutron absorbing fluid in the first cavity 710 is prevented from entering the second cavity 720 under the action of gravity, thereby making it difficult to adjust the reactivity by using the change in the content of the neutron absorbing fluid in the second cavity 720.

[0047] See also Figure 6In some embodiments, the middle and upper part of the second cavity 720 may be filled with a capillary structure 73, and the tube wall at the lower part of the second cavity 720 may be provided with a capillary structure 73, so that the neutron absorbing fluid is kept above the inert gas under the action of its surface tension and the capillary structure 73. In such an embodiment, by providing the capillary structure 73 at the middle and upper part of the second cavity 720 and the capillary structure 73 at the tube wall at the lower part of the second cavity 720, the capillary force of the capillary structure 73 and the surface tension of the neutron absorbing fluid can be utilized, so that the inert gas and the neutron absorbing fluid are automatically separated, and the inert gas is located below the neutron absorbing fluid.

[0048] See also Figure 7 In some embodiments, the second cavity 720 may be filled with a capillary structure 73, and along the length direction of the second cavity 720, the capillary structure 73 becomes denser and denser toward the first cavity 710; the capillary structure 73 closer to the first cavity 710 is denser, and the capillary structure 73 farther away from the first cavity 710 is sparser, so that the neutron absorbing fluid is kept above the inert gas under the action of its surface tension and the capillary structure 73. In such an embodiment, through the above arrangement, the capillary force of the capillary structure 73 and the surface tension of the neutron absorbing fluid can be utilized, so that the inert gas and the neutron absorbing fluid are automatically separated, and the inert gas is located below the neutron absorbing fluid.

[0049] In some embodiments, the capillary structure 73 may be a capillary mesh wick structure.

[0050] In some embodiments, the core 10 includes a fuel 50, a radial reflective layer 40, and two axial reflective layers 30. The two axial reflective layers 30 are respectively disposed at the axial ends of the fuel 50, and the radial reflective layer 40 is disposed radially outside the fuel 50. The reflective layer is used to prevent the radiation and heat generated by the fuel 50 from leaking in the axial and radial directions of the core 10.

[0051] In some embodiments, the evaporator section of the sodium heat pipe is inserted into the fuel 50. The tube 72 is also inserted into the fuel 50.

[0052] In some embodiments, the shell 71 may be a cylindrical shell, and the tubes 72 are arranged along the circumference of the shell 71. The heat pipes are arranged along the circumference in the core 10. There is a gap between the tubes 72 and the heat pipes to avoid mutual interference.

[0053] In some embodiments, the tube 72 may be located radially inward of the heat pipe so as to be disposed close to the center of the core 10. The closer the tube 72 is to the center of the core 10, the greater the effect of the neutron absorbing fluid in the tube 72 on the reactivity of the reactor. When the amount of the neutron absorbing fluid in the core changes, the change in reactivity is also greater.

[0054] In some embodiments, the core 10 is an annular structure, and a safety rod channel 60 is formed on the radial inner side thereof. In such embodiments, the shell 71 may be an annular structure.

[0055] In some embodiments, the shell 71 can be arranged as close to the core 10 as possible. In some embodiments, the space nuclear reactor further includes a shielding body arranged between the core 10 and the thermoelectric conversion element. The shell 71 can be located between the core 10 and the shielding body. The space between the core 10 and the shielding body is limited. If the distance between the shell 71 and the core 10 is too large, the cross-sectional size and the total volume weight of the shielding body will become too large. Therefore, the shell 71 should be arranged as close to the core 10 as possible to reduce the distance between the core 10 and the shielding body.

[0056] The reactive adjusting member 70 in the embodiment of the present application has a simple structure and high feasibility.

[0057] Since the reactivity loss due to burnup during the life cycle is basically a certain value, the greater the reactivity introduced by the unit temperature drop (1K) of the fuel 50, the smaller the temperature drop of the fuel 50 during the entire life cycle (the temperature drop of the fuel 50 during the entire life cycle is equal to the ratio of the reactivity loss due to burnup to the reactivity introduced by the unit temperature drop of the fuel 50). The reactivity introduced by the unit temperature drop of the fuel 50 is determined by the volume of the shell 71, the number, position and size of the pipes 72, etc. For example: for the unit temperature drop of the fuel 50, the larger the volume of the shell 71, the greater the volume change of the neutron absorbing fluid, and the greater the amount of the neutron absorbing fluid removed from the core 10, thereby introducing greater reactivity and reducing the total temperature drop of the fuel 50 during the life cycle.

[0058] The dimensions of the shell 71 and the pipe 72 can be designed according to the specific reactor parameter requirements. Through the reasonable design of the shell 71 and the pipe 72, even for a high-power reactor with a fast burnup rate, it can have an autonomous operation characteristic similar to the Kilopower space reactor in the United States. The burnup reactivity loss can be compensated by a small drop in the fuel 50 temperature, and the critical operation of the reactor can be maintained without the intervention of any active control system.

[0059] Regarding the embodiments of the present application, it should also be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other to obtain new embodiments.

[0060] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A reactivity regulating device suitable for a space nuclear reactor, characterized in that: include: A heat transfer element, used for transferring heat from the core of the space nuclear reactor to the outside of the core; A reactivity regulating member forms a sealed cavity filled with a neutron absorbing fluid, wherein the sealed cavity comprises a first cavity arranged outside the core and a second cavity arranged inside the core and fluidly connected to the first cavity, wherein the first cavity is thermally connected to the heat transfer member so that the temperature of the neutron absorbing fluid in the first cavity changes accordingly with the temperature of the core, and the content of the neutron absorbing fluid in the second cavity changes due to the thermal expansion and contraction effect, thereby regulating the reactivity of the core.

2. The responsiveness adjustment device according to claim 1, characterized in that: The reactive adjustment member comprises: a shell member, the shell member being disposed outside the core, the shell member forming a first cavity; A plurality of tubes, the tubes extending from the inside of the core to be connected to the shell, each of the tubes forming a second cavity, the second cavity being in fluid communication with the first cavity to form the sealed cavity together; The heat transfer member is thermally connected to the shell member so that the temperature of the shell member changes in the same direction as the temperature in the core, thereby causing the volume of the neutron absorbing fluid in the first cavity to change accordingly due to thermal expansion and contraction, thereby causing the content of the neutron absorbing fluid in the second cavity to change.

3. The responsiveness adjustment device according to claim 2, characterized in that: The shell member forms a heat transfer through hole; The heat transfer element is inserted into the heat transfer through hole and is heat-conductively connected to the hole wall of the heat transfer through hole.

4. The responsiveness adjustment device according to claim 2, characterized in that: The second chamber is also filled with an inert gas, and the inert gas is located below the neutron absorbing fluid.

5. The responsiveness adjustment device according to claim 4, characterized in that: The first cavity is filled with a capillary structure so that the neutron absorbing fluid is retained in the first cavity under the action of its surface tension and the capillary structure.

6. The responsiveness adjustment device according to claim 4, characterized in that: The upper middle part of the second cavity is filled with a capillary structure, and the tube wall of the lower part of the second cavity is provided with a capillary structure, so that the neutron absorbing fluid is kept above the inert gas under the action of its surface tension and the capillary structure.

7. The responsiveness adjustment device according to claim 4, characterized in that: The second cavity is filled with a capillary structure, and along the length direction of the second cavity, the capillary structure becomes increasingly dense towards the first cavity; The capillary structure closer to the first cavity is denser, and the capillary structure farther away from the first cavity is sparser, so that the neutron absorbing fluid is kept above the inert gas under the action of its surface tension and the capillary structure.

8. The responsiveness adjustment device according to claim 2, characterized in that: The neutron absorbing fluid is Li-6.

9. The responsiveness adjustment device according to claim 2, characterized in that: The volume of the first cavity is more than 10 times the volume of the entire second cavity.

10. The responsiveness adjustment device according to any one of claims 2 to 9, characterized in that: The heat transfer element is a sodium heat pipe.

11. A space nuclear reactor, characterized in that: include: The core, used to provide heat; A thermoelectric conversion element, disposed outside the core, for converting heat from the core into electrical energy; The reactivity regulating device according to any one of claims 1 to 10 is used to regulate the reactivity of the core.

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