Heat conduction structure and molten salt reactor cabin

Abstract

The utility model provides a heat conduction structure and a molten salt reactor cabin. The heat conduction structure comprises a first pipeline, a heat conduction layer and at least one heat pipe, the first pipeline is provided with a first end face and a second end face at two ends; the heat conduction layer is arranged on the periphery of the first pipeline from the first end face in the length direction of the first pipeline. The heat conduction layer is shorter than the first pipeline; a plurality of channels are formed in the end face of the side, away from the first end face, of the heat conduction layer in the axial direction of the heat conduction layer. Two ends of the heat pipe are closed; one end of each heat pipe is arranged in the channel, and the other end of each heat pipe faces the second end face, so that the part, located in the heat conduction layer, of each heat pipe serves as a condensation section, and the part, not located in the heat conduction layer, of each heat pipe serves as an evaporation section in the working state. Fused salt freezing blockage in the fused salt pipeline can be effectively prevented, and the temperature uniformity of the fused salt pipeline is improved; and the dismounting difficulty of the molten salt reactor cabin through-wall pipeline can be reduced, so that the heat conduction structure is easy to maintain, and the safety and the reliability of the molten salt reactor cabin are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of heat conduction structure and molten salt reactor vessel. BACKGROUND

[0002] In high-temperature molten salt reactor, fuel salt loading pipeline, one loop cooling salt inlet and outlet pipeline penetrates the reactor vessel wall structure, in the process of starting operation, to avoid molten salt solidification, pipeline needs to be heated and insulated design.Reactor and passive residual heat removal system heat exchange device is located in lower reactor vessel.The structure of lower reactor vessel is reactor vessel, reactor vessel insulation layer, lower safety vessel, serpentine stone concrete and ordinary concrete in turn from inside to outside.Cooling salt loop inlet and outlet pipe and fuel salt loading and discharging pipe are connected to reactor vessel from lower reactor vessel wall outside.

[0003] According to the melting point of reactor core fuel salt, the temperature of pipeline is required to be higher than 550 DEG C.Meanwhile, to meet the requirement of lower reactor vessel shielding design, the opening diameter of lower reactor vessel concrete radiation shielding layer is required to be not more than 400 mm;In current design, high-temperature pipeline is wound with heating belt to realize pipeline preheating and heating.Heating belt is further provided with heat insulation structure outside to reduce temperature to within the limit value of wall body.Considering that the thickness of concrete wall can reach 1m, plus the insulation inside reactor vessel and the distance of pipeline to reactor vessel, the length of wall-penetrating pipeline needing heating is greater than 1m, to ensure the uniformity of entire pipeline, multiple temperature control heating is often used.Heating belt and temperature control thermocouple have high damage probability, once damaged, due to the existence of radioactivity in reactor vessel, it is difficult to disassemble and replace the heating and insulation of pipeline in reactor vessel and wall body.

[0004] Therefore, it is necessary to study more reliable heating and insulation mode to ensure that the temperature of pipeline is above the solidification point of molten salt. CONTENT OF UTILITY MODEL

[0005] In order to overcome the defects that heating of high-temperature molten salt pipeline of reactor vessel often causes freezing and is difficult to disassemble and maintain in prior art, the utility model provides a kind of heat conduction structure and molten salt reactor vessel.The heat conduction structure of the utility model makes full use of the high-efficiency heat conduction advantage of heat pipe, effectively prevents molten salt pipeline from freezing, and improves the uniformity of molten salt pipeline;Due to the simple structure of heat pipe, installation is more convenient, when it is used in reactor vessel of molten salt reactor, based on the long service life and single-head filling characteristics of heat pipe, the difficulty of disassembling wall-penetrating pipeline of molten salt reactor vessel is reduced, the heat conduction structure is easy to maintain, thereby the safety and reliability of molten salt reactor vessel are improved.

[0006] The utility model solves the above technical problem by the following technical scheme:

[0007] This utility model provides a heat-conducting structure, which includes a first pipe, a heat-conducting layer, and at least one heat pipe; the first pipe has a first end face and a second end face located at both ends; the heat-conducting layer is disposed around the first pipe along the length direction of the first pipe from the first end face; the length of the heat-conducting layer is less than the length of the first pipe; a plurality of channels are formed along the axial direction of the heat-conducting layer from the end face away from the first end face; both ends of the heat pipe are closed; one end of each heat pipe is disposed in the channel, and the other end is disposed facing the second end face, so that in the working state, the part of each heat pipe in the heat-conducting layer is used as a condensation section, and the part not in the heat-conducting layer is used as an evaporation section.

[0008] In this invention, the first pipe may be referred to as a molten salt pipe in the art, and the temperature of the first pipe is generally higher than 600°C during operation.

[0009] In this invention, the working fluid in the evaporation section, after being heated, will transfer external heat to the molten salt in the first pipe, thereby achieving heat tracing of the first pipe and preventing the molten salt from freezing and blocking.

[0010] In some embodiments, the heat-conducting structure further includes a heating element disposed in the portion of the heat pipe that is not located in the heat-conducting layer.

[0011] In a specific implementation, the heating element includes a heating band; preferably, the heating band is a glass fiber heating tape, a ceramic heating tape, or a heating rod, to meet the heating requirements of the first pipe above 500°C and to better fit with the heat pipe.

[0012] In a specific implementation, the heating element is arranged around the periphery of the first pipe and the heat pipe from the second end face to the end of the heat-conducting layer away from the first end face.

[0013] In some embodiments, the number of heat pipes is 2-6; preferably, the number of heat pipes is 2; more preferably, the number of heat pipes is 4-6, in order to improve temperature uniformity and reduce installation difficulty.

[0014] In a specific implementation, each heat pipe is symmetrically arranged on the outer surface of the first pipe with the central axis of the first pipe as the center, so that each heat pipe is symmetrically distributed along the circumference of the first pipe.

[0015] In some embodiments, the length of the heat pipe is greater than the length of the first pipe, and one end of the heat pipe is flush with the first end face, while the other end extends beyond the second end face.

[0016] In some embodiments, the diameter of the heat pipe is 5-20 mm, for example 10 mm; the diameter of the heat pipe can be designed according to the wall material and the channels on the wall to ensure that the temperature of the wall is within the limits of the wall material and to transfer as much heat as possible to avoid freezing blockage of the hot molten salt in the first pipe during transportation.

[0017] In some embodiments, the portion of the heat pipe located within the thermally conductive layer accounts for 50% to 80% of the total length of the heat pipe.

[0018] In some embodiments, the portion of the heat pipe not located in the heat-conducting layer accounts for 20% to 50% of the total length of the heat pipe; within this range, the latent heat of vaporization must be greater than or equal to the heat required for the melting of the working fluid in the evaporation and condensation sections, as well as the heat dissipation from the condensation section (mainly the heat required for the heat tracing pipe and the internal molten salt), thus avoiding the possibility of excessive heat dissipation from the working fluid and encountering the cold start limit.

[0019] In a specific implementation, the portion of the heat pipe within the heat-conducting layer accounts for 80% of the total length of the heat pipe; the portion of the heat pipe not within the heat-conducting layer accounts for 20% of the total length of the heat pipe.

[0020] In this invention, the evaporation section corresponds to the portion of the heat pipe not located in the heat-conducting layer, and the condensation section corresponds to the portion of the heat pipe located in the heat-conducting layer. The calculation formulas for the lengths of the evaporation section and the condensation section are as follows:

[0021] The ratio of the length of the evaporation section to the length of the condensation section can be judged by the criterion that FLS > 1; FLS is the ratio of the latent heat of the working medium in the evaporation section to the heat absorbed in the condensation section. If this ratio is greater than 1, the heat pipe can be started from a cold state.

[0022]

[0023]

[0024]

[0025]

[0026] Q fg Q is the latent heat of vaporization of the working medium in the evaporation section. fu Including the latent heat of vaporization of the working medium in the condensation section (m c h fu And the sensible heat (cp) of the condenser section tube wall and the wick. w m w +cp w m we For heat pipes in the reactor compartment, they are generally started up under good insulation conditions, therefore Qc It can be ignored.

[0027] The mass of the working medium in each section is m for the evaporation section. e Insulation section m a and condensation section m c The calculation method is as follows:

[0028]

[0029]

[0030] in Porosity of the liquid-absorbing core R represents the density of the working medium. w R is the inner radius of the heat pipe. v The diameter of the steam chamber and the length of the evaporation section are given. and condensation section length ;

[0031] .

[0032] In some embodiments, the length of the heat-conducting structure is 1 to 3 m.

[0033] In one embodiment, the length of the heat-conducting structure is 3m; the portion of the heat pipe within the heat-conducting layer is 2.4m; and the portion of the heat pipe not within the heat-conducting layer accounts for 0.6m of the total length of the heat pipe.

[0034] In some embodiments, the channel extends from one end face of the thermally conductive layer away from the first end face to the other end face.

[0035] In a specific implementation, the length of the portion of each heat pipe that is in the heat-conducting layer is equal to the length of the portion that is not in the heat-conducting layer.

[0036] In this invention, the heat-conducting layer and the first pipe can be an integral structure or a separate structure; wherein, the integral structure can improve the heat transfer effect through the integration of the heat-conducting layer and the pipe; the separate structure enhances heat transfer by attaching the heat-conducting block to the outer wall of the heat pipe.

[0037] In one embodiment, the heat-conducting layer and the first pipe are integrally formed. A plurality of first channels are formed along the axial direction on the side wall of the heat-conducting layer, and each first channel is used to accommodate the heat pipe. Preferably, the heat-conducting layer is disposed on the periphery of the first pipe by welding, for example by diffusion welding, so as to achieve the integration of the heat-conducting layer and the first pipe. Preferably, the first pipe can be directly processed into an integral structure with a raised periphery and channels that can accommodate the heat pipe.

[0038] In one embodiment, the heat-conducting layer and the first pipe are separate structures. The heat-conducting layer is composed of several arc-shaped blocks, and each arc-shaped block has a notch along its axial direction at its cross-section. The notches are joined together by splicing the arc-shaped blocks to form a second channel, and each second channel is used to accommodate the heat pipe. Preferably, the cross-section of each second channel is irregular or circular. When the cross-section of each second channel is circular, the processing difficulty of the heat pipe and the channel is reduced.

[0039] For areas where the heat tracing cable is difficult to cover or inconvenient to disassemble, an irregularly shaped heat pipe can be used in the strong radiation zone near the reactor core. The cross-section of the irregularly shaped heat pipe is irregular.

[0040] In some embodiments, the material of the heat-conducting layer is the same as the material of the first pipe.

[0041] In some embodiments, the thermally conductive layer is made of carbon steel, which has higher thermal conductivity.

[0042] In some embodiments, the portion of the heat pipe not in the thermally conductive layer is filled with a thermally conductive medium between itself and the first pipe; preferably, the thermally conductive medium includes thermally conductive silicone grease or nickel foam; using nickel foam as a thermally conductive medium has a softer texture, which can ensure adhesion and enhance thermal conductivity.

[0043] In some implementations, the heat pipe is a straight pipe.

[0044] In some embodiments, the portion of the heat pipe not in the heat-conducting layer is bent downwards, allowing the working fluid in the condensation section to flow back by gravity.

[0045] In some embodiments, the heat pipe is used to be filled with a working medium.

[0046] In a specific embodiment, the working medium is an alkaline earth metal; preferably, the working medium is one or more of sodium, potassium, rubidium, and cesium; more preferably, the working medium is a sodium-potassium alloy.

[0047] In this invention, the sodium and potassium contents in the sodium-potassium alloy can be 22.8% and 77.2%, respectively, where % represents the mass percentage of each component in the sodium-potassium alloy; the melting point of the sodium-potassium alloy is -12.3℃, and it is liquid at room temperature, making it easy to start.

[0048] In a specific implementation, the amount of the working medium is 1 / 5 to 1 / 3 of the volume of the heat pipe.

[0049] In some embodiments, the wall thickness of the heat pipe is 1-3 mm.

[0050] In some embodiments, the inner wall of the heat pipe is provided with one or more of the following: a wire mesh structure, a groove structure, and a sintered wick structure.

[0051] For heat pipes longer than 1.5m and placed horizontally, a grooved structure and / or a sintered wick structure are used to prevent the wire mesh from detaching from the wall due to lack of support during long-term operation; when a wire mesh structure is used, a spring support and other structural designs are implemented.

[0052] In some embodiments, the heat pipe is made of a material that is resistant to high temperatures and has good compatibility with the working fluid, such as stainless steel or Hastelloy.

[0053] In some embodiments, the thermally conductive structure is further provided with an insulating material around it; preferably, the insulating material includes nanoparticles, which have better insulation effect at the same thickness; preferably, the insulating material is one or both of aluminum silicate fiber and alumina fiber.

[0054] In this invention, preferably, the assembly method of the heat-conducting structure includes split structure assembly and integrated structure assembly.

[0055] For the integrated structure, a portion of the heat pipe (condensation section) can be directly inserted into the channel of the heat-conducting layer outside the first pipe, while the other portion of the heat pipe (evaporation section) not located in the heat-conducting layer is wrapped with heating tape, and then the outer side of the integrated structure is covered with insulation cotton to complete the assembly.

[0056] For a split structure, the heat-conducting layer blocks are first positioned around the first pipe. Then, a portion of the heat pipe (condensation section) is inserted into the channel formed between the blocks, and the entire structure is secured using clamps or other methods. The other portion of the heat pipe not located in the heat-conducting layer (evaporation section) is wrapped with heating tape, and the entire structure is covered with insulation cotton to complete the assembly.

[0057] This utility model also provides a molten salt reactor chamber, which includes a hollow chamber, a reactor disposed inside the chamber, and a heat-conducting structure as described above. The heat-conducting structure is disposed in a hole in the side wall of the chamber, and one end of the heat-conducting structure is connected to the molten salt pipeline of the molten salt reactor chamber.

[0058] In some embodiments, the cabin comprises, from the inside out, a hollow layer, a pod-side insulation layer, and a pod concrete wall; the heat-conducting structure penetrates the hollow layer, the pod-side insulation layer, and the pod concrete wall.

[0059] In some embodiments, the diameter of the hole is greater than or equal to that of the heat-conducting structure to meet the requirements of radiation protection; preferably, the diameter of the hole is ≤400mm; more preferably, the diameter of the heat-conducting structure is less than 400mm.

[0060] After determining the location of the holes and the heat-conducting structure, the gaps between the holes and the heat-conducting structure are filled with aerogel.

[0061] In some embodiments, the heat-conducting structure extends from its connection with the molten salt pipe to the outside of the molten salt stack chamber; preferably, the heat-conducting layer of the heat-conducting structure is located in a hole in the side wall of the chamber, and the portion of the heat pipe not located in the heat-conducting layer is located outside the chamber, so as to facilitate the disassembly and maintenance of the heating band on the heat pipe.

[0062] In this invention, before the reactor is started, the heat-conducting structure is used to preheat the first pipe. The preheating temperature needs to be higher than the freezing point of the molten salt. After the reactor is started, the heat of the equipment in the reactor compartment is transferred to the heat pipe to achieve heat tracing of the first pipe. At this time, the heating power can be reduced according to the temperature signal feedback of the first pipe.

[0063] In this invention, the heat pipe may include a liquid filling pipe, which is located outside the chamber; when the heat pipe fails, the liquid filling pipe can be evacuated after the reactor is shut down.

[0064] This invention is not limited to the use of molten salt pipes in the through holes of molten salt stack chambers for heat tracing. It can also be applied to molten salt stack chambers and other applications where there are molten salt pipes, but it is difficult to use heating belts for heat tracing or to disassemble and repair them.

[0065] The positive and progressive effects of this utility model are as follows:

[0066] (1) The present application is based on the heat pipe technology heat conduction structure, which makes full use of the heat pipe’s efficient heat transfer performance, and achieves uniform temperature tracing of high temperature molten salt pipeline through the heat conduction layer, avoiding molten salt freezing blockage, realizing effective heat conduction and heat preservation, and improving the pipeline temperature uniformity; preferably, when it is used in molten salt pile, it improves the uniformity of molten salt pipeline, making the temperature difference less than 10°C, and avoiding molten salt solidification and blockage.

[0067] (2) The molten salt stack chamber of this application uses heat pipe heat conduction, which can reduce the disassembly difficulty of the through pipe of the molten salt stack chamber based on the long life of the heat pipe and the single-head filling characteristics, making the heat conduction structure easy to maintain, thereby improving the safety and reliability of the molten salt stack chamber; specifically, the service life of the heat pipe can reach more than 10 years; it is suitable for simple or complex high temperature pipe structures that are difficult to disassemble internally but require heat tracing; it is not limited to the use of heat tracing of molten salt pipes in the through hole of the stack chamber. Attached Figure Description

[0068] Figure 1 This is a perspective view of the heat-conducting structure of Embodiment 1 of this application;

[0069] Figure 2 This is a front view of the heat-conducting structure of Embodiment 1 of this application;

[0070] Figure 3 This is a schematic diagram of the structure of the heat-conducting layer and the first pipe in Embodiment 1 of this application;

[0071] Figure 4 This is a flowchart illustrating the assembly process of the split-type heat-conducting structure in Embodiment 1 of this application.

[0072] Figure 5 This is a front view of the heat-conducting structure of Embodiment 2 of this application;

[0073] Figure 6 This is a right view of the heat-conducting structure of Embodiment 2 of this application;

[0074] Figure 7 This is a schematic diagram of the molten salt stack chamber in Embodiment 3 of this application.

[0075] Explanation of reference numerals in the attached figures:

[0076] Heat pipe 1

[0077] Thermal conductive layer 2

[0078] First Pipeline 3

[0079] First end face 301

[0080] Second end face 302

[0081] Heating belt 4

[0082] Thermal insulation material 5

[0083] Concrete wall 6

[0084] 7-layer insulation layer on the side of the stack

[0085] Reactor 8

[0086] Holes 9 on the side wall of the hull

[0087] Evaporation section 10

[0088] Condensation section 11

[0089] Filling tube 12

[0090] Channel 13

[0091] Safety Container 14. Detailed Implementation

[0092] The present invention will be described more clearly and completely below with reference to the accompanying drawings and some preferred embodiments.

[0093] Example 1

[0094] This embodiment discloses a heat-conducting structure. Figure 1 This is a perspective view of the heat-conducting structure in this embodiment; Figure 2 This is a front view of the heat-conducting structure in this embodiment; Figure 3 This is a schematic diagram of the structure of the heat-conducting layer and the first pipe in this embodiment; Figure 4 This is a flowchart illustrating the assembly process of the split-type heat-conducting structure in this embodiment.

[0095] This heat-conducting structure is a split-type high-temperature pipeline heat tracing and insulation structure; it includes a first pipeline 3, a heat-conducting layer 2, a heating band 4, and four heat pipes 1; the first pipeline 3 has a first end face 301 and a second end face 302 located at both ends; the heat-conducting layer 2 is located around the first pipeline 3 along the length direction of the first pipeline 3 from the first end face 301; the length of the heat-conducting layer 2 is less than the length of the first pipeline 3; four channels 13 are opened along the axial direction of the heat-conducting layer 2 from the end face away from the first end face 301; both ends of the heat pipes 1 are closed; one end of each heat pipe 1 is located in the channel 13, and the other end is located facing the second end face 302, so that the part of each heat pipe 1 in the heat-conducting layer 2 is used as the condensation section 11 and the part not in the heat-conducting layer 2 is used as the evaporation section 10 in the working state.

[0096] The heat-conducting structure is placed horizontally and has a total length of 3m; the evaporation section 10 has a length of 0.6m and the condensation section 11 has a length of 2.4m.

[0097] The heating band 4 is a glass fiber heat tracing tape and is located on the portion of the heat pipe 1 that is not within the heat-conducting layer 2. From the second end face 302 to the end of the heat-conducting layer 2 away from the first end face 301, the heating band 4 is wrapped around the periphery of the first pipe 3 and the heat pipe 1. Each heat pipe 1 is symmetrically attached to the outer surface of the first pipe 3 with the central axis of the first pipe 3 as the center.

[0098] The length of heat pipe 1 is greater than the length of the first pipe 3, and one end of heat pipe 1 is flush with the first end face 301, while the other end extends beyond the second end face 302. The length of the portion of each heat pipe 1 within the heat-conducting layer 2 is equal to the length of the portion not within the heat-conducting layer 2.

[0099] The heat-conducting layer 2 consists of four arc-shaped blocks. Each arc-shaped block has a notch along its axial direction at its cross-section. The notches are joined together by splicing the arc-shaped blocks to form a second channel. Each second channel is used to accommodate the heat pipe 1. The cross-section of each second channel is circular.

[0100] The first pipe 3 is made of Hastelloy alloy, with an outer diameter of 48.3 mm. The molten salt temperature inside the pipe is required to be higher than 550℃. The heat-conducting layer 2 is made of a 1 / 4 arc-shaped carbon steel block with a thickness of 16 mm. The diameter of the second channel is the same as the outer diameter of the heat pipe, both being 10 mm. The shell of the heat pipe 1 is made of stainless steel, and the internal working fluid is a sodium-potassium alloy with a filling rate of 20%. The inner wall of the pipe is provided with grooved liquid-absorbing channels.

[0101] The thermally conductive structure is also surrounded by insulation material 5; the insulation material is aluminum silicate fiber.

[0102] In this embodiment, the heat-conducting structure is assembled by first assembling the first pipe outside the stack compartment using a heat tracing and insulation structure. The assembly method includes the following steps:

[0103] First, the heat-conducting layer 2 blocks are positioned around the first pipe 3. At this time, the structure is not yet strictly fixed. Then, the heat pipe 1 is inserted into the channel 13 between the blocks, and the blocks are welded and fastened together.

[0104] Then, heating tape 4 is wrapped around the condensation section 11 of heat pipe 1, and the outer side of the overall structure is covered with insulation material 5. The outer diameter of insulation material 5 is 380mm, which is slightly smaller than the inner diameter of the hole 9 on the side wall of the cabin.

[0105] After the heat-conducting structure is assembled, it is inserted into the hole 9 on the side wall of the compartment to achieve docking between the first pipe 3 and the equipment inside the compartment.

[0106] This embodiment is based on a heat pipe technology-based heat conduction structure. It makes full use of the heat pipe's high-efficiency heat transfer performance and uses a heat conduction layer to achieve uniform temperature tracing of the high-temperature molten salt pipeline, avoiding molten salt freezing and blockage, thus achieving effective heat conduction and insulation and improving the pipeline temperature uniformity.

[0107] Example 2

[0108] This embodiment discloses a heat-conducting structure; Figure 5 This is a front view of the heat-conducting structure in this embodiment; Figure 6 This is a right view of the heat-conducting structure of this embodiment; the portion of heat pipe 1 not in the heat-conducting layer 2 is bent downwards; other structures are the same as in embodiment 1.

[0109] Example 3

[0110] This embodiment discloses a molten salt reactor chamber, which includes a hollow chamber, a reactor 8 disposed inside the chamber, and a heat-conducting structure as described in Embodiment 1. The heat-conducting structure is disposed in a hole in the side wall of the chamber, and one end of the heat-conducting structure is connected to the molten salt pipe of the reactor 8.

[0111] The heat-conducting structure extends from the outside to the inside through a 0.6m concrete wall 6, a 0.5m stack compartment side insulation layer 7, and a 0.5m air layer (the gap between the safety container 14 and the side insulation layer).

[0112] The cabin, from the inside out, includes a hollow layer, a stack side insulation layer 7, and a stack concrete wall 6; the heat-conducting structure penetrates the hollow layer, the stack side insulation layer 7, and the stack concrete wall 6.

[0113] The diameter of the holes 9 on the side wall of the cabin is greater than or equal to that of the heat-conducting structure; the diameter of the holes 9 on the side wall of the cabin is ≤400mm; the diameter of the heat-conducting structure is less than 400mm.

[0114] The heat-conducting structure extends from the connection with the molten salt pipe to the outside of the molten salt stack chamber; the heat-conducting layer 2 of the heat-conducting structure is located in the hole 9 on the side wall of the chamber, and the part of the heat pipe 1 not in the heat-conducting layer 2 is located outside the chamber; the heat pipe 1 includes a liquid filling pipe 12, which is located outside the chamber; when the heat pipe fails, the liquid filling pipe 12 can be evacuated after the stack is shut down.

[0115] This embodiment uses heat pipe heat conduction, which can reduce the difficulty of disassembling the through-wall pipes of the molten salt stack chamber based on the long life and single-head filling characteristics of heat pipes, making the heat conduction structure easy to maintain, thereby improving the safety and reliability of the molten salt stack chamber; it is suitable for simple or complex high-temperature pipe structures that are difficult to disassemble internally but require heat tracing.

[0116] Example 1

[0117] This effect embodiment demonstrates the effect of the molten salt stack chamber of Example 3 in practical application.

[0118] Before reactor startup, the pipelines are preheated. The temperature of the heat pipe evaporation section is 600℃. Analysis shows that the temperature difference between the outside of the first pipeline and the equipment inside the reactor compartment is less than 10℃, and the lowest temperature of the first pipeline is 590℃, which meets the operating temperature of 550℃ for the molten salt pipeline. Thermocouples inserted into the outer wall of the heat-conducting layer are used to provide feedback signals for constant temperature heating of the system. After reactor startup, the temperature of the reactor rises due to nuclear heat, and the temperature of the pipelines connected to it also rises. The heating belt of the heat pipe evaporation section automatically reduces the heating power based on the temperature signal feedback.

[0119] If the heat tracing cable is damaged during system operation, the reactor shall be shut down or the pipeline shall be cooled as required, and the heat tracing cable shall be replaced on the outside of the reactor compartment.

[0120] Based on irradiation analysis and experimental experience, the service life of heat pipes can reach more than 10 years. If a heat pipe fails, an oxygen-free filling device is used to connect to the filling pipe of the failed heat pipe for vacuuming or filling.

[0121] Example 3 describes the heat-conducting structure in the molten salt reactor compartment, namely the high-temperature pipeline heat tracing and insulation structure. Heat pipes provide heat tracing throughout the reactor compartment pipelines, effectively improving the temperature uniformity of the molten salt pipelines and reducing the occurrence of problems such as molten salt solidification and blockage. Maintenance and other operations for the heat tracing tape and heat pipes are all located outside the reactor compartment, allowing for maintenance without stopping the reactor, reducing maintenance difficulty and minimizing personnel radiation risks.

Claims

1. A thermally conductive structure, characterized in that, It includes a first conduit, a heat-conducting layer, and at least one heat pipe; the first conduit has a first end face and a second end face located at both ends thereof; The heat-conducting layer is disposed around the periphery of the first pipe from the first end face along the length of the first pipe; the length of the heat-conducting layer is less than the length of the first pipe. Several channels are formed along the axial direction of the heat-conducting layer on the side of the heat-conducting layer away from the first end face; Both ends of the heat pipe are closed; one end of each heat pipe is located in the channel, and the other end is located facing the second end face, so that in the working state, the part of each heat pipe in the heat-conducting layer is used as the condensation section, and the part not in the heat-conducting layer is used as the evaporation section.

2. The thermally conductive structure as described in claim 1, characterized in that, The heat-conducting structure further includes a heating element, which is disposed on the portion of the heat pipe that is not located in the heat-conducting layer. The heating element includes a heating band; From the second end face to the end of the heat-conducting layer away from the first end face, the heating element is arranged around the periphery of the first pipe and the heat pipe.

3. The thermally conductive structure as described in claim 1, characterized in that, The thermally conductive structure satisfies one or more of the following conditions: ① The number of heat pipes is 2-6; each heat pipe is symmetrically attached to the outer surface of the first pipe with the central axis of the first pipe as the center; ②The length of the heat pipe is greater than the length of the first pipe, and one end of the heat pipe is flush with the first end face, while the other end extends beyond the second end face; ③The diameter of the heat pipe is 5-20mm.

4. The thermally conductive structure as described in claim 1, characterized in that, The thermally conductive structure satisfies one or more of the following conditions: ① The portion of the heat pipe located within the heat-conducting layer accounts for 50% to 80% of the total length of the heat pipe; ② The portion of the heat pipe not located in the heat-conducting layer accounts for 20% to 50% of the total length of the heat pipe; ③ The length of the heat-conducting structure is 1~3m; ④ The channel extends from one end face of the heat-conducting layer away from the first end face to the other end face.

5. The thermally conductive structure as described in claim 4, characterized in that, The length of the portion of each heat pipe that is in the heat-conducting layer is equal to the length of the portion that is not in the heat-conducting layer.

6. The thermally conductive structure as described in claim 1, characterized in that, The heat-conducting layer and the first pipe are an integral structure. Several first channels are formed along the axial direction on the side wall of the heat-conducting layer, and each first channel is used to accommodate the heat pipe. Alternatively, the heat-conducting layer and the first pipe are separate structures. The heat-conducting layer is composed of several arc-shaped blocks. Each arc-shaped block has a notch along its axial direction at its cross-section. By splicing the arc-shaped blocks together, the notches are combined in pairs to form a second channel. Each second channel is used to accommodate the heat pipe.

7. The thermally conductive structure as described in claim 1, characterized in that, The thermally conductive structure satisfies one or more of the following conditions: ① The portion of the heat pipe not located in the heat-conducting layer is bent downwards; ②The wall thickness of the heat pipe is 1-3mm; ③The inner wall of the heat pipe is provided with one or more of the following: wire mesh structure, groove structure, and sintered liquid wick structure; ④ The heat-conducting structure is also surrounded by insulation material.

8. A molten salt stacking chamber, characterized in that, It includes a hollow cabin, a reactor disposed inside the cabin, and a heat-conducting structure as described in any one of claims 1-7, wherein the heat-conducting structure is disposed in a hole in the side wall of the cabin, and one end of the heat-conducting structure is connected to the molten salt pipe of the reactor.

9. The molten salt stacking tank as described in claim 8, characterized in that, The molten salt stack chamber meets one or more of the following conditions: ①The cabin body comprises, from the inside out, a hollow layer, a side insulation layer of the sump, and a concrete wall of the sump; the heat-conducting structure penetrates the hollow layer, the side insulation layer of the sump, and the concrete wall of the sump. ② The diameter of the hole is greater than or equal to that of the heat-conducting structure; ③ The heat-conducting structure extends from the connection point with the molten salt pipe to the outside of the molten salt stack chamber.

10. The molten salt stacking tank as described in claim 9, characterized in that, The molten salt stack chamber meets one or two of the following conditions: ① The diameter of the hole is ≤400mm; the diameter of the heat-conducting structure is less than 400mm; ② The heat-conducting layer of the heat-conducting structure is located in the holes on the side wall of the cabin, and the part of the heat pipe that is not in the heat-conducting layer is located outside the cabin.

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