Heat conduction structure, application thereof and molten salt reactor cabin

Abstract

The invention provides a heat conduction structure, application thereof 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 invention relates to a heat-conducting structure and application thereof and a molten salt pile cabin. Background Art

[0002] In a high-temperature molten salt reactor, the fuel salt loading pipeline and the primary cooling salt inlet and outlet pipelines run through the reactor compartment wall structure. During the startup and operation process, in order to prevent the molten salt from solidifying when it is cold, the pipelines need to be designed for heat tracing and insulation. The heat exchange device of the reactor body and the passive residual heat removal system is located in the lower reactor compartment. The structure of the lower reactor compartment from the inside to the outside is the reactor vessel, the reactor compartment insulation layer, the lower safety container, serpentine concrete and ordinary concrete. The high-temperature molten salt pipelines such as the cooling salt loop inlet and outlet pipes and the fuel salt loading and discharge pipes are connected to the reactor vessel from the outside of the lower reactor compartment wall.

[0003] According to the melting point of the core fuel salt, the pipe temperature is required to be higher than 550℃. At the same time, in order to meet the requirements of the shielding design of the lower compartment, the opening diameter of the radiation shielding layer of the lower compartment concrete is required to be no more than 400 mm; in the current design, the heating tape is wrapped around the high-temperature pipeline to achieve pipeline preheating and heating. A thermal insulation structure is set outside the heating tape to reduce the temperature to within the use limit of the wall. Considering that the thickness of the concrete wall can reach 1m, plus the insulation inside the compartment and the distance from the pipeline to the container. The length of the through-wall pipeline that needs to be heated is greater than 1m. In order to ensure the uniform temperature of the entire pipeline, multi-stage temperature control heating is often used. The heating tape and temperature control thermocouple are more likely to be damaged. Once damaged, due to the presence of radioactivity in the compartment, it is difficult to disassemble and replace the heating and insulation of the pipelines in the compartment and the wall.

[0004] Therefore, it is necessary to study more reliable heating and insulation methods to ensure that the pipeline temperature is above the solidification point of the molten salt. Summary of the invention

[0005] In order to overcome the defects of the prior art that the heating of the high-temperature molten salt pipeline in the reactor compartment often causes freezing and is difficult to disassemble and repair, the present invention provides a heat-conducting structure and its application and a molten salt reactor compartment. The heat-conducting structure of the present invention makes full use of the high-efficiency heat-conducting advantage of the heat pipe, effectively prevents the molten salt in the molten salt pipeline from freezing, and improves the temperature uniformity of the molten salt pipeline; since the heat pipe has a simple structure and is more convenient to install, it is used in the compartment of the molten salt reactor. Based on the long life and single-head filling characteristics of the heat pipe, the difficulty of disassembling the through-the-wall pipeline in the molten salt reactor compartment can be reduced, and the heat-conducting structure is easy to maintain, thereby improving the safety and reliability of the molten salt reactor compartment.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] One of the technical solutions provided by the present invention is: a heat-conducting structure, which includes a first pipeline, a heat-conducting layer and at least one heat pipe; the first pipeline has a first end face and a second end face located at both ends thereof; the heat-conducting layer is arranged on the periphery of the first pipeline along the length direction of the first pipeline from the first end face; the length of the heat-conducting layer is less than the length of the first pipeline; a plurality of channels are opened along the axial direction of the heat-conducting layer from the end face of the heat-conducting layer away from the first end face; both ends of the heat pipe are closed; one end of each of the heat pipes is arranged in the channel, and the other end is arranged toward the second end face, so as to make the part of each heat pipe in the heat-conducting layer serve as a condensation section and the part not in the heat-conducting layer serve as an evaporation section in a working state.

[0008] In the present 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 the present invention, after being heated, the working fluid in the evaporation section transfers external heat to the molten salt in the first pipe, thereby achieving heating of the first pipe and avoiding freezing and blockage of the molten salt.

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

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

[0012] In a specific embodiment, the heating element is disposed around the first pipeline and the periphery of the heat pipe from the second end surface to the end of the heat conductive layer away from the first end surface.

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

[0014] In a specific implementation, the heat pipes are symmetrically arranged on the outer surface of the first pipe with the central axis of the first pipe as the center, so that the heat pipes are 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 surface, and the other end exceeds the second end surface.

[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 channel on the wall to ensure that the temperature of the wall is within the limit of the wall material and to transfer as much heat as possible to avoid freezing of the hot molten salt in the first pipe during transportation.

[0017] In some embodiments, the portion of the heat pipe in the heat 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 that is not in the heat conductive layer accounts for 20% to 50% of the total length of the heat pipe; within this range, the requirement that the latent heat of evaporation must be greater than or equal to the sum of the heat required for melting the working fluid in the evaporation section and the condensation section and the heat dissipated to the outside of the condensation section (mainly the heat required for the heating pipeline and the internal molten salt) can be met, thereby avoiding the possibility of encountering a cold start limit due to excessive heat dissipation of the working fluid.

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

[0020] In the present invention, the evaporation section corresponds to the portion of the heat pipe that is not in the heat conduction layer, and the condensation section corresponds to the portion of the heat pipe that is in the heat conduction layer. The calculation formulas for the lengths of the evaporation section and the condensation section are as follows:

[0021] The length ratio of the evaporation section to the condensation section can be judged by FLS>1; FLS is the ratio of the latent heat of the working medium in the evaporation section to the heat absorbed by 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] Where Q fg is the latent heat of vaporization of the working medium in the evaporation section, Q fu Including the latent heat of vaporization of the working medium in the condensation section (m c )h fu , and the sensible heat of the tube wall and the wick in the condensation section (cp w m w +cp w m we )∆t, for the heat pipes in the reactor compartment, they are usually started under good insulation conditions, so Qc Can be ignored.

[0027] Among them, the mass of the working medium in each section is the evaporation section m e 、Adiabatic section m a and condensation section m c The calculation method is as follows:

[0028]

[0029]

[0030] in is the wick porosity, is the density of the working medium. w is the inner radius of the heat pipe, R v is the diameter of the steam chamber, the length of the evaporation section Le and the length of the condensation section Lc;

[0031] .

[0032] In some embodiments, the length of the thermally conductive structure is 1-3 m.

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

[0034] In some embodiments, the channel is opened from one end surface of the heat conductive layer away from the first end surface to the other end surface.

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

[0036] In the present invention, the heat-conducting layer and the first pipe can be an integrated structure or a split structure; wherein the integrated structure can improve the heat transfer effect by integrating the heat-conducting layer and the pipe; the split structure enhances heat transfer by fitting the heat-conducting block to the outer wall of the heat pipe.

[0037] In a certain embodiment, the heat-conducting layer and the first pipe are an integrated structure, and a plurality of first channels are opened on the side wall surface of the heat-conducting layer along its axial direction, and each first channel is used to accommodate the heat pipe respectively; preferably, the heat-conducting layer is arranged on the periphery of the first pipe by welding, for example, by diffusion welding, so as to realize the integration of the heat-conducting layer and the first pipe; preferably, the first pipe can be directly processed into an integrated structure with a protruding periphery and a channel that can accommodate the heat pipe.

[0038] In a certain embodiment, the heat conductive layer and the first pipe are split structures, and the heat conductive layer is composed of a plurality of arc-shaped blocks. A notch is provided at the cross section of each arc-shaped block along its axial direction, and the notches are combined in pairs to form a second channel by splicing the arc-shaped blocks, and each second channel is used to accommodate the heat pipe respectively; 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] Among them, for areas where the heating tape is difficult to cover or inconvenient to remove, special-shaped heat pipes with special-shaped cross-sections can be used in the strong radiation area close to the core.

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

[0041] In some embodiments, the material of the heat conductive layer includes carbon steel, which has higher thermal conductivity.

[0042] In some embodiments, a heat-conducting medium is filled between the portion of the heat pipe that is not in the heat-conducting layer and the first pipe; preferably, the heat-conducting medium includes thermal grease or nickel foam; nickel foam is used as the heat-conducting medium because it is softer and can ensure adhesion and enhance thermal conductivity.

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

[0044] In some embodiments, the portion of the heat pipe that is not in the heat conductive layer is bent downward so that the working fluid in the condensation section can flow back by gravity.

[0045] In some embodiments, the heat pipe is configured 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 the present invention, the contents of sodium and potassium in the sodium-potassium alloy may be 22.8% and 77.2% respectively, where % is the mass percentage of each component in the sodium-potassium alloy; the melting point of the sodium-potassium alloy is -12.3°C, and it is liquid at room temperature and is easy to start.

[0048] In a specific implementation, the filling amount of the working medium accounts for 1 / 5-1 / 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 a wire mesh structure, a groove structure and a sintered liquid wick structure.

[0051] Among them, for heat pipes with a length greater than 1.5m and placed horizontally, a groove structure and / or a sintered liquid wick structure is 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, structural designs such as spring supports are performed.

[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, a thermal insulation material is further provided on the periphery of the heat-conducting structure; preferably, the thermal insulation material includes nanoparticles, which have a better thermal insulation effect under the condition of equal thickness; preferably, the thermal insulation material is one or both of aluminum silicate fiber and alumina fiber.

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

[0055] Among them, for the integrated structure, a part of the heat pipe (condensation section) can be directly inserted into the channel of the heat conductive layer outside the first pipe, and the other part of the heat pipe (evaporation section) not arranged in the heat conductive layer is wrapped with a heating belt, and then the outer side of the overall structure is covered with thermal insulation cotton to complete the assembly.

[0056] For the split structure, the blocks of the heat-conducting layer can be positioned around the first pipe, and then a part of the heat pipe (condensing section) can be inserted into the channel formed between the blocks, and the whole structure can be fastened with a clamp or other means. The other part of the heat pipe (evaporating section) not in the heat-conducting layer is wrapped with a heating belt, and the outer side of the whole structure is covered with thermal insulation cotton to complete the assembly.

[0057] The second technical solution provided by the present invention is: an application of the heat-conducting structure as described above in a molten salt reactor.

[0058] The third technical solution provided by the present invention is: a molten salt stack compartment, which includes a hollow cabin, a reactor arranged inside the cabin, and the heat-conducting structure as described above, wherein the heat-conducting structure is arranged in a hole on the side wall of the cabin, and one end of the heat-conducting structure is connected to the molten salt pipeline of the molten salt stack compartment.

[0059] In some embodiments, the cabin body includes a hollow layer, a cabin side insulation layer and a cabin concrete wall from the inside to the outside; the heat conductive structure runs through the hollow layer, the cabin side insulation layer and the cabin concrete wall.

[0060] In some embodiments, the diameter of the hole is greater than or equal to the heat-conducting structure to meet the needs of radiation protection; preferably, the diameter of the hole is ≤400 mm; preferably, the diameter of the heat-conducting structure is less than 400 mm.

[0061] After the positions of the holes and the heat-conducting structure are determined, the gaps between the holes and the heat-conducting structure are filled with aerogel.

[0062] In some embodiments, the heat-conducting structure extends from the connection with the molten salt pipeline to the outside of the molten salt stack compartment; preferably, the heat-conducting layer of the heat-conducting structure is located in the holes on the side wall of the compartment, and the portion of the heat pipe that is not in the heat-conducting layer is located outside the compartment, so as to facilitate the disassembly and maintenance of the heating belt on the heat pipe.

[0063] In the present invention, before the reactor is started, the heat-conducting structure is required to preheat the first pipe, and 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 heating of the first pipe. At this time, the heating power can be reduced according to the temperature signal feedback of the first pipe.

[0064] In the present invention, the heat pipe may include a liquid-filled pipe, and the liquid-filled pipe is arranged outside the cabin; when the heat pipe fails, the liquid-filled pipe may be evacuated after the reactor is shut down.

[0065] The present invention is not limited to the use of heating molten salt pipes in holes passing through the molten salt reactor compartment, but is also applicable to pipes or other structural parts in the molten salt reactor compartment and other uses where there are molten salt pipes but it is difficult to heat them with heating belts or difficult to disassemble and repair them.

[0066] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0067] The reagents and raw materials used in the present invention are commercially available.

[0068] The positive and progressive effects of the present invention are:

[0069] (1) The heat-conducting structure of the present invention is based on the heat pipe technology, which makes full use of the efficient heat transfer performance of the heat pipe, realizes uniform temperature heating of the high-temperature molten salt pipeline by means of the heat-conducting layer, avoids freezing and blockage of the molten salt, realizes effective heat conduction and heat preservation, and improves the temperature uniformity of the pipeline; preferably, when it is used in a molten salt pile, the temperature uniformity of the molten salt pipeline is improved, so that the temperature difference therein is less than 10°C, and blockage caused by solidification of the molten salt is avoided.

[0070] (2) The molten salt reactor compartment of the present invention adopts heat pipes for heat conduction. Based on the long service life and single-head filling characteristics of the heat pipes, the difficulty of disassembling the through-wall pipes in the molten salt reactor compartment can be reduced, making the heat conduction structure easy to maintain, thereby improving the safety and reliability of the molten salt reactor compartment. Specifically, the service life of the heat pipes can reach more than 10 years. It is suitable for simple or complex high-temperature pipeline structures that are difficult to disassemble internally but require heating. It is not limited to the use of heating molten salt pipes in the through-holes in the compartment. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 A three-dimensional diagram of the heat-conducting structure of Example 1 of the present application;

[0072] Figure 2 It is a front view of the heat-conducting structure of Example 1 of the present application;

[0073] Figure 3 This is a schematic diagram of the structure of the heat-conducting layer and the first pipeline of Example 1 of the present application;

[0074] Figure 4 This is an assembly flow chart of the split heat-conducting structure of Example 1 of the present application;

[0075] Figure 5 It is a front view of the heat-conducting structure of Example 2 of the present application;

[0076] Figure 6 It is a right side view of the heat conducting structure of Example 2 of the present application;

[0077] Figure 7 This is a schematic diagram of the structure of the molten salt reactor compartment of Example 3 of the present application.

[0078] Description of reference numerals:

[0079] Heat pipe 1

[0080] Thermal conductive layer 2

[0081] First pipeline 3

[0082] First end surface 301

[0083] Second end surface 302

[0084] Heating belt 4

[0085] Insulation material 5

[0086] Concrete wall 6

[0087] Compartment side insulation layer 7

[0088] Reactor 8

[0089] Holes in the side wall of the cabin 9

[0090] Evaporation section 10

[0091] Condensation section 11

[0092] Filling pipe 12

[0093] Channel 13

[0094] Safety container 14. DETAILED DESCRIPTION

[0095] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0096] Example 1

[0097] This embodiment discloses a heat conduction structure. Figure 1 is a three-dimensional diagram of the heat-conducting structure of this embodiment; Figure 2 is a front view of the heat conducting structure of this embodiment; Figure 3 is a schematic structural diagram of the heat-conducting layer and the first pipeline of this embodiment; Figure 4 FIG. 4 is an assembly flow chart of the split heat-conducting structure of this embodiment.

[0098] The heat-conducting structure belongs to a split-type high-temperature pipeline heat tracing and insulation structure; it includes a first pipeline 3, a heat-conducting layer 2, a heating belt 4 and four heat pipes 1; the first pipeline 3 has a first end face 301 and a second end face 302 located at its two ends; the heat-conducting layer 2 is arranged on the periphery of 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 on the end face of the heat-conducting layer 2 away from the first end face 301 along the axial direction of the heat-conducting layer 2; the two ends of the heat pipe 1 are closed; one end of each heat pipe 1 is arranged in the channel 13, and the other end is arranged toward the second end face 302, so as to make the part of each heat pipe 1 in the heat-conducting layer 2 as a condensation section 11 and the part not in the heat-conducting layer 2 as an evaporation section 10 in the working state.

[0099] The heat-conducting structure is placed horizontally and has a total length of 3 m; the length of the evaporation section 10 is 0.6 m, and the length of the condensation section 11 is 2.4 m.

[0100] The heating belt 4 is a glass fiber heating belt and is arranged on the portion of the heat pipe 1 that is not in the heat conductive layer 2. From the second end surface 302 to the end of the heat conductive layer 2 away from the first end surface 301, the heating belt 4 is arranged 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.

[0101] The length of the heat pipe 1 is greater than that of the first pipe 3, and one end of the heat pipe 1 is flush with the first end surface 301, and the other end exceeds the second end surface 302. The length of the portion of each heat pipe 1 in the heat conducting layer 2 is equal to the length of the portion not in the heat conducting layer 2.

[0102] The heat conducting layer 2 is composed of four arc blocks, each arc block has a notch along its axial direction, and the notches are combined in pairs to form a second channel by splicing the arc blocks. Each second channel is used to accommodate a heat pipe 1 respectively; the cross section of each second channel is circular.

[0103] The first pipe 3 is made of Hastelloy with an outer diameter of 48.3mm. The temperature of the molten salt in the pipe is required to be higher than 550°C. The heat conducting layer 2 is made of a 1 / 4 arc carbon steel block with a thickness of 16mm. The diameter of the second channel is consistent with the outer diameter of the heat pipe, both of which are 10mm. The shell of the heat pipe 1 is made of stainless steel, the internal working fluid is sodium-potassium alloy, the filling rate is 20%, and a groove liquid absorption core channel is set on the inner wall of the pipe.

[0104] A heat-insulating material 5 is also provided on the periphery of the heat-conducting structure; the heat-insulating material is aluminum silicate fiber.

[0105] When assembling the heat-conducting structure of this embodiment, the first pipeline is firstly assembled with the heat-tracing and heat-insulating structure outside the reactor compartment. The assembly method includes the following steps:

[0106] First, the blocks of the heat conducting layer 2 are positioned around the first pipe 3, and 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.

[0107] Afterwards, the heating belt 4 is wound around the condensing section 11 of the heat pipe 1, and the outer side of the overall structure is covered with a heat-insulating material 5, the outer diameter of the heat-insulating material 5 is 380 mm, which is slightly smaller than the inner diameter of the hole 9 on the side wall of the cabin;

[0108] After the heat-conducting structure is assembled, the structure is inserted into the hole 9 on the side wall of the cabin to achieve docking between the first pipeline 3 and the equipment in the cabin.

[0109] This embodiment is based on the heat conduction structure of the heat pipe technology, which makes full use of the efficient heat transfer performance of the heat pipe, realizes uniform temperature heating of the high-temperature molten salt pipeline by means of the heat conduction layer, avoids freezing and blockage of the molten salt, realizes effective heat conduction and heat preservation, and improves the temperature uniformity of the pipeline.

[0110] Example 2

[0111] This embodiment discloses a heat-conducting structure; Figure 5 is a front view of the heat conducting structure of this embodiment; Figure 6 It is a right side view of the heat conducting structure of this embodiment; the portion of the heat pipe 1 not in the heat conducting layer 2 is bent downward; the other structures are the same as those of the first embodiment.

[0112] Example 3

[0113] The present embodiment discloses a molten salt reactor cabin, which includes a hollow cabin body, a reactor 8 arranged inside the cabin body, and a heat-conducting structure as described in Example 1, wherein the heat-conducting structure is arranged in a hole on the side wall of the cabin body, and one end of the heat-conducting structure is connected to the molten salt pipeline of the reactor 8.

[0114] The heat-conducting structure penetrates the 0.6m concrete wall 6, the 0.5m bunker side insulation layer 7 and the 0.5m air layer (the gap between the safety container 14 and the side insulation layer) from the outside to the inside.

[0115] The cabin body includes a hollow layer, a cabin side insulation layer 7 and a cabin concrete wall 6 from the inside to the outside; the heat-conducting structure runs through the hollow layer, the cabin side insulation layer 7 and the cabin concrete wall 6;

[0116] The diameter of the hole 9 on the side wall of the cabin is greater than or equal to that of the heat-conducting structure; the diameter of the hole 9 on the side wall of the cabin is ≤400mm; the diameter of the heat-conducting structure is less than 400mm;

[0117] The heat-conducting structure extends from the connection with the molten salt pipeline to the outside of the molten salt reactor cabin; the heat-conducting layer 2 of the heat-conducting structure is located in the hole 9 on the side wall of the cabin, and the part of the heat pipe 1 not in the heat-conducting layer 2 is located outside the cabin; the heat pipe 1 includes a liquid filling pipe 12, and the liquid filling pipe 12 is arranged outside the cabin; when the heat pipe fails, the liquid filling pipe 12 can be vacuumed after the stack is shut down.

[0118] This embodiment adopts the heat conduction method of heat pipes. Based on the long life and single-head filling characteristics of the heat pipes, it can reduce the difficulty of disassembling the wall-penetrating pipes in the molten salt reactor compartment, make the heat conduction structure easy to maintain, and thus improve the safety and reliability of the molten salt reactor compartment; it is suitable for simple or complex high-temperature pipe structures that are difficult to disassemble internally but require heating.

[0119] Effect Example 1

[0120] This effect embodiment is the effect of the molten salt reactor compartment of Example 3 during actual application.

[0121] Before the reactor is started, the pipeline is preheated and the temperature of the heat pipe evaporation section is 600°C. After analysis, the temperature difference from the outside of the first pipeline to the equipment in the reactor compartment is less than 10°C, and the lowest temperature of the first pipeline is 590°C, which meets the operating temperature of the molten salt pipeline of 550°C. The system is heated at a constant temperature using the feedback signal of a thermocouple inserted on the outer wall of the heat conductive layer. After the reactor is started, the temperature of the reactor rises due to nuclear heat generation, and the temperature of the pipe section 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.

[0122] If the heating tape is damaged during system operation, the reactor will be shut down or the pipeline will be cooled down as required, and the heating tape will be replaced outside the reactor compartment.

[0123] According to irradiation analysis and experimental experience, the service life of heat pipes can reach more than 10 years. If a heat pipe fails, oxygen-free filling equipment is used to connect the liquid filling pipe of the failed heat pipe to perform vacuum or liquid filling.

[0124] Example 3 The heat-conducting structure in the molten salt reactor cabin, i.e., the high-temperature pipeline heat tracing and insulation structure, uses heat pipes to achieve heat tracing throughout the cabin pipeline, which can effectively improve the temperature uniformity of the molten salt pipeline and reduce the occurrence of problems such as molten salt solidification and blockage. The maintenance of the heating belt and heat pipes are all located outside the cabin, which can achieve maintenance without stopping the reactor, reduce the difficulty of maintenance and reduce the risk of radiation to personnel.

Claims

1. A heat-conducting structure, characterized in that: It includes a first pipeline, a heat-conducting layer and at least one heat pipe; the first pipeline has a first end surface and a second end surface located at both ends thereof; The heat-conducting layer is arranged at the periphery of the first pipe along the length direction of the first pipe from the first end surface; the length of the heat-conducting layer is less than the length of the first pipe; A plurality of channels are opened along the axial direction of the heat-conducting layer on an end surface of the heat-conducting layer away from the first end surface; Both ends of the heat pipe are closed; one end of each heat pipe is arranged in the channel, and the other end is arranged toward the second end surface, so that in the working state, the part of each heat pipe in the heat conductive layer is used as a condensation section, and the part not in the heat conductive layer is used as an evaporation section.

2. The heat conducting structure according to claim 1, characterized in that: The heat-conducting structure further comprises a heating element, wherein the heating element is disposed at a portion of the heat pipe that is not in the heat-conducting layer; Preferably, the heating element comprises a heating belt; more preferably, the heating belt is a glass fiber heating belt, a ceramic heating belt or a heating rod; Preferably, the heating element is disposed around the first pipeline and the periphery of the heat pipe from the second end surface to an end of the heat conductive layer away from the first end surface.

3. The heat conducting structure according to claim 1, characterized in that: The heat-conducting structure satisfies one or more of the following conditions: ① The number of the heat pipes is 2-6; preferably, the number of the heat pipes is 2; preferably, the number of the heat pipes is 4-6; preferably, each of the heat pipes is symmetrically attached to the outer surface of the first pipe with the central axis of the first pipe as the center; ② The length of the heat pipe is greater than that of the first pipe, and one end of the heat pipe is flush with the first end surface, and the other end exceeds the second end surface; ③The diameter of the heat pipe is 5-20 mm, for example 10 mm.

4. The heat conducting structure according to claim 1, characterized in that: The heat-conducting structure satisfies one or more of the following conditions: ① The portion of the heat pipe in 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 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 is opened from one end surface of the heat conductive layer away from the first end surface to the other end surface.

5. The heat-conducting structure according to claim 4, characterized in that: The length of a portion of each heat pipe located in the heat conducting layer is equal to the length of a portion not located in the heat conducting layer.

6. The heat conducting structure according to claim 1, characterized in that: The heat-conducting layer and the first pipe are an integrated structure, and a plurality of first channels are provided on the side wall surface of the heat-conducting layer along its axial direction, and each of the first channels is used to accommodate the heat pipe respectively; preferably, the heat-conducting layer is provided on the periphery of the first pipe by welding; Alternatively, the heat-conducting layer and the first pipe are of a split structure, the heat-conducting layer is composed of a plurality of arc-shaped blocks, a notch is provided at the cross section of each arc-shaped block along its axial direction, and the notches are combined in pairs to form a second channel by splicing the arc-shaped blocks, and each second channel is used to accommodate the heat pipe respectively; preferably, the cross-section of each second channel is irregular or circular.

7. The heat-conducting structure according to claim 1, characterized in that: The heat-conducting structure satisfies one or more of the following conditions: ① The material of the heat-conducting layer includes carbon steel; ② A heat-conducting medium is filled between the portion of the heat pipe not in the heat-conducting layer and the first pipe; preferably, the heat-conducting medium includes heat-conducting silicone grease or nickel foam; ③ The portion of the heat pipe not in the heat conducting layer is bent downward; ④ The heat pipe is filled with a working medium; Preferably, the working medium is an alkaline earth metal; more preferably, the working medium is one or more of sodium, potassium, rubidium and cesium; for example, the working medium is a sodium-potassium alloy; Preferably, the filling amount of the working medium accounts for 1 / 5-1 / 3 of the volume of the heat pipe; ⑤ The wall thickness of the heat pipe is 1-3 mm; ⑥ The inner wall of the heat pipe is provided with one or more of a wire mesh structure, a groove structure and a sintered liquid wick structure; ⑦ The heat pipe is made of stainless steel or Hastelloy; ⑧The periphery of the heat-conducting structure is also provided with a heat-insulating material; preferably, the heat-insulating material comprises nanoparticles; preferably, the heat-insulating material is one or both of aluminum silicate fibers and aluminum oxide fibers.

8. Use of the heat-conducting structure according to any one of claims 1 to 7 in a molten salt reactor.

9. A molten salt reactor compartment, characterized in that: It includes a hollow cabin, a reactor arranged inside the cabin, and a heat-conducting structure as described in any one of claims 1 to 7, wherein the heat-conducting structure is arranged in a hole on the side wall of the cabin, and one end of the heat-conducting structure is connected to the molten salt pipeline of the reactor.

10. The molten salt reactor compartment according to claim 9, characterized in that: The molten salt reactor compartment meets one or more of the following conditions: ① The cabin body includes a hollow layer, a cabin side insulation layer and a cabin concrete wall from the inside to the outside; the heat-conducting structure runs through the hollow layer, the cabin side insulation layer and the cabin concrete wall; ② The diameter of the hole is greater than or equal to the heat-conducting structure; preferably, the diameter of the hole is ≤400 mm; preferably, the diameter of the heat-conducting structure is less than 400 mm; ③ The heat-conducting structure extends from the connection with the molten salt pipeline to the outside of the molten salt pile compartment; preferably, the heat-conducting layer of the heat-conducting structure is located in the holes on the side wall of the compartment, and the portion of the heat pipe not in the heat-conducting layer is located outside the compartment.

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