Heat exchanger and liquid metal fast reactor accident residual heat removal system

Abstract

The embodiment of the invention relates to the field of reactor emergency cooling devices, in particular to a heat exchanger and a liquid metal fast reactor accident waste heat removal system. According to the heat exchanger provided by the embodiment of the invention, the liquid metal flowing pipeline is arranged to be capable of improving the heat exchange efficiency, so that the liquid metal medium in the liquid metal flowing pipeline fully exchanges heat with air driven by the air flowing assembly, and the removal efficiency of waste heat of a reactor core is improved. On the other hand, the embodiment of the invention provides a liquid metal fast reactor accident waste heat removal system, by adopting the heat exchanger, the heat exchange efficiency is improved, and efficient operation of the waste heat removal system is ensured.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of reactor emergency cooling devices, and in particular to a heat exchanger and a liquid metal fast reactor accident residual heat removal system. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] When a reactor accident occurs, it is necessary to shut down the reactor. Although the reaction in the reactor has stopped, the core is still releasing heat. If the residual heat of the core is not discharged outside the reactor, the core temperature will continue to rise, eventually causing the core to melt, and even causing nuclear leakage. Therefore, a heat exchanger containing a heat-conducting medium is needed to discharge the residual heat. Among them, the thermal conductivity of liquid metal medium is much higher than that of non-metallic media such as water and air. 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] One aspect of an embodiment of the present application provides a heat exchanger, which is suitable for a liquid metal fast reactor accident residual heat removal system, and comprises: a shell, a liquid metal conveying component, and a liquid metal flow pipeline, wherein the liquid metal conveying component is fixedly connected to the shell, the liquid metal flow pipeline is fixedly connected to the liquid metal conveying component, and an air flow component is fixedly connected to the shell, the liquid metal conveying component is configured so that liquid metal from the liquid metal fast reactor flows into the liquid metal conveying component and flows out of the liquid metal conveying component after heat exchange with air in the shell through the liquid metal flow pipeline; the air flow component is configured so that air from the outside enters the shell and flows out of the shell after heat exchange with the liquid metal; the liquid metal flow pipeline is configured to reduce the probability of leakage and improve the heat exchange efficiency of the heat exchanger.

[0006] Another aspect of an embodiment of the present application provides a liquid metal fast reactor accident residual heat removal system, which includes the aforementioned heat exchanger.

[0007] The heat exchanger provided in the embodiment of the present application improves the heat exchange efficiency by configuring the liquid metal flow pipeline so that the liquid metal medium in the liquid metal flow pipeline and the air driven by the air flow component can fully exchange heat, thereby improving the efficiency of removing the residual heat from the core.

[0008] The liquid metal fast reactor accident waste heat removal system provided in the embodiment of the present application improves the heat exchange efficiency, reduces the leakage probability, and ensures the safe and efficient operation of the waste heat removal system by adopting the aforementioned heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] 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.

[0010] Figure 1 is a schematic diagram of the heat exchanger structure provided in an embodiment of the present application;

[0011] Figure 2 It is a schematic diagram of the local structure of the liquid metal flow pipeline provided in the embodiment of the present application.

[0012] Description of reference numerals:

[0013] 1. Shell; 100. Heat exchanger; 2. Liquid metal delivery assembly; 21. Input collector; 22. Output collector; 3. Liquid metal flow pipeline; 31. First finned tube section; 32. Second finned tube section; 33. Bend section; 4. Air flow assembly; 41. Air damper; 42. Flow distributor; 43. Chimney; 5. Support member. DETAILED DESCRIPTION

[0014] 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.

[0015] 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.

[0016] The disclosure below provides a plurality of different embodiments or examples to implement the present application. In order to simplify the disclosure of the present application, the parts and methods of specific examples are described below. Of course, they are merely examples, and the purpose is not to limit the present application. In the description of the embodiments of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically limited.

[0017] The existing liquid metal coolant air heat exchangers have adopted the tube bundle structure of vertical light tubes, vertical fin tubes, space bends, and spiral light tubes. When the heat exchange demand is the same, the vertical light tube and space bend heat exchanger have sparse spatial structures and low equipment space utilization. The vertical fin tube and spiral light tube have large chimney heights under the natural circulation requirements, which greatly increases the overall cost. The liquid metal medium has a high temperature. If the sodium medium leaks and comes into contact with the air, it will react. The liquid lead-bismuth medium, as a toxic medium, will also cause great harm after leakage. The boundary integrity of the heat exchange tube is crucial to the safe operation of the equipment. Therefore, a heat exchanger with a low leakage risk and a high level of miniaturization is needed to improve the safety, reliability and economy of the equipment.

[0018] One aspect of an embodiment of the present application provides a heat exchanger applicable to a liquid metal fast reactor accident residual heat removal system. Figure 1 The heat exchanger structure diagram provided in the embodiment of the present application is shown. In some embodiments, Figure 1 As shown, it includes: a shell 1, a liquid metal conveying component 2, a liquid metal flow pipeline 3, the liquid metal conveying component 2 is fixedly connected to the shell 1, the liquid metal flow pipeline 3 is fixedly connected to the liquid metal conveying component 2, and an air flow component 4 is fixedly connected to the shell 1. The liquid metal conveying component 2 is configured so that liquid metal from a liquid metal fast reactor flows into the liquid metal conveying component 2, and flows out of the liquid metal conveying component 2 after heat exchange with air in the shell 1 through the liquid metal flow pipeline 3; the air flow component 4 is configured so that air from the outside enters the shell 1 and flows out of the shell 1 after heat exchange with the liquid metal; the liquid metal flow pipeline 3 is configured to improve the heat exchange efficiency of the heat exchanger.

[0019] The heat exchanger 100 provided in the embodiment of the present application is configured to improve the heat exchange efficiency and reduce the leakage probability by configuring the liquid metal flow pipeline 3 so that the liquid metal medium in the liquid metal flow pipeline 3 and the air driven by the air flow component 4 can fully exchange heat, thereby improving the efficiency of removing the residual heat from the core.

[0020] In some embodiments, the air flow component 4 can be configured to adopt a passive natural circulation heat removal method, so that it can be put into operation in time when an accident occurs and no additional external force is required.

[0021] In some embodiments, the liquid metal flow pipeline 3 is configured to have fins formed on its surface, and the liquid metal flow pipeline 3 is configured to be bendably disposed on the liquid metal delivery component 2 .

[0022] In some embodiments, the liquid metal flow pipeline 3 is configured to form fins on the surface, which can expand the contact area between the liquid metal flow pipeline 3 and the air compared to a bare tube without fins. At the same time, the fins can quickly conduct heat, so that the heat of the liquid metal medium in the liquid metal flow pipeline 3 is quickly dispersed to the fins, thereby accelerating the exchange of heat in the liquid metal medium and the air, thereby improving the heat exchange efficiency of the heat exchanger.

[0023] The liquid metal flow pipeline 3 is arranged to be bendably arranged on the liquid metal delivery component 2. Compared with a straight pipe form, the spatial structure of the liquid metal flow pipeline 3 can be made denser, thereby saving layout space.

[0024] In some embodiments, the liquid metal flow pipeline 3 is formed in the following manner: fins are welded along a first direction at a first predetermined length of the liquid metal flow pipeline 3, and after welding is completed, fins are welded along a second direction at a second predetermined length of the portion of the liquid metal flow pipeline 3 where no fins are welded, and a pipeline of a third predetermined length is reserved between the two parts of the liquid metal flow pipeline 3 where the fins are welded, and it can be bent.

[0025] Figure 2 The schematic diagram of the local structure of the liquid metal flow pipeline provided by the embodiment of the present application is shown. In some embodiments, Figure 2As shown, the liquid metal flow pipeline 3 is divided into predetermined sections, wherein one end of the smooth straight tube is welded with fins along the first direction, and the welding range is less than a predetermined length of half the total length of the smooth straight tube, forming a first fin tube section 31; and the end of the smooth straight tube without fins is welded with fins along the second direction, forming a second fin tube section 32. During processing, for example, the length range of the welded fins of the first fin tube section 31 and the second fin tube section 32 can be equal to form symmetry along the midpoint of the length of the original smooth straight tube, and the lengths of the two can also be adopted in other suitable ways. The above is only an example and does not constitute a limitation on the technical solution of the present invention. A predetermined distance is reserved between the first fin tube section 31 and the second fin tube section 32. The smooth straight tube within this range has no welded fins. The liquid metal flow pipeline 3 as a whole is bent from the part without welded fins, so the part without welded fins is called a bending section 33. Through the above-mentioned segmentation, smooth straight tubes can be processed into bent finned tubes, which saves space and improves the heat exchange efficiency of the liquid metal flow pipeline 3. There is no need to weld independent tubes together when processing the smooth straight tubes into the shape of the liquid metal flow pipeline 3. Instead, the liquid metal flow pipeline 3 is formed in one piece, thereby reducing the number of welding joints, reducing the risk of leakage of the liquid metal flow pipeline 3, and improving the safety of the heat exchanger 100.

[0026] In some embodiments, the bending radius of the bend is determined according to the heat exchange requirements. The smaller the bending radius, the greater the deformation and stress of the bending section 33, the lower the thermal conductivity of the bending section 33, and the improvement of the heat exchange efficiency is affected; the larger the bending radius, the smaller the impact on the thermal conductivity of the bending section 33, but it will cause the spatial structure of the liquid metal flow pipeline 3 to become relatively sparse, affecting the compression of the layout space. Therefore, it is necessary to determine the bending radius according to the actual heat exchange requirements of the reactor, which can take into account both miniaturization and heat exchange efficiency. In some embodiments, the fin welding method, the support structure setting method, and the length of the first fin tube section 31 and the second fin tube section 32 can be determined according to the bending radius. In some embodiments, the size and number of fins are determined according to the heat exchange requirements. Too many fins will cause the gap between the fins to become smaller, increase the airflow resistance, reduce the air flow rate in the air flow component 4, which is not conducive to the rapid exchange of heat, and too many fins are prone to accumulate dust in the gap, which will also lead to a decrease in heat exchange efficiency. Therefore, it is necessary to determine the size and number of fins according to the actual heat exchange requirements of the reactor.

[0027] In some embodiments, Figure 2As shown, the liquid metal delivery assembly 2 includes an input collector 21 and an output collector 22, and the input collector 21 and the output collector 22 are respectively arranged to be fixedly connected to the shell 1. The liquid metal from the liquid metal fast reactor flows in from the input collector 21, and after heat exchange with the air in the shell 1 through the liquid metal flow pipeline 3, it flows out from the output collector 22, and the liquid metal flow pipeline 3 is respectively fixedly connected to the input collector 21 and the output collector 22. Among them, the input collector 21 distributes the liquid metal medium to the liquid metal flow pipeline 3, and the liquid metal medium in the tube exchanges heat with the air in countercurrent through the base tube and fins of the liquid metal flow pipeline 3, and then flows into the output collector 22 and returns to the liquid metal fast reactor.

[0028] In some embodiments, Figure 1 As shown, the air flow component 4 may include a damper 41, a chimney 43 and a flow distributor 42. The damper 41 is arranged at the inlet of the shell 1, and the air from the outside enters the shell 1 through the damper 41. The flow distributor 42 is arranged in the shell 1, and is configured to adjust the flow of the air entering through the damper 41. The chimney 43 is arranged at the outlet of the shell 1 to discharge the air after heat exchange from the shell 1.

[0029] In some embodiments, the air flow component 4 can adopt a non-passive natural circulation method. An extraction chimney is set at the outlet to provide a driving force for air flow for the air flow component 4. A flow distribution component 42 is set at the inlet so that the air is evenly transported to a predetermined position near the inlet when passing through the inlet, such as the position of the second fin tube section 32. The uniform air flow can improve the heat exchange performance of the heat exchanger 100.

[0030] In some embodiments, the heat exchanger 100 further includes a support member 5 , which is disposed on the shell 1 and is configured to support and position the liquid metal flow pipeline 3 and prevent the liquid metal flow pipeline 3 from experiencing flow-induced vibration.

[0031] In some embodiments, since the center of gravity of the liquid metal flow pipeline 3 is unstable in a bent state, a support member 5 is required to position and support the liquid metal flow pipeline 3 on the shell to enhance the stability of the liquid metal flow pipeline 3 and prevent the flow-induced vibration of the liquid metal medium in the pipeline from damaging the liquid metal flow pipeline 3.

[0032] In some embodiments, the structure of the support member 5 is determined according to the liquid metal flow pipeline 3 and the flow-induced vibration. When determining the structure of the support member 5, not only the liquid metal flow pipeline 3 but also the flow-induced vibration is considered, so that the structure of the support member 5 determined in this way can better support the liquid metal flow pipeline to achieve a better heat exchange effect.

[0033] Another aspect of the embodiments of the present application provides a liquid metal fast reactor accident residual heat removal system, which includes the aforementioned heat exchanger 100.

[0034] Since the shell 1 of the aforementioned heat exchanger 100 adopts a bent liquid metal flow pipeline 3 with fins, the height required for manufacturing the heat exchanger 100 is reduced, and the pipeline layout space is saved, so that the heat exchanger 100 is miniaturized under the same heat exchange demand; and the bent structure will not increase the air resistance too much, which is conducive to air circulation and heat exchange; the integrated bent structure is adopted to reduce the number of welding joints, reduce the risk of leakage, and improve the safety of the fast reactor accident residual heat removal system.

[0035] 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.

[0036] The above are only specific implementation methods 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 heat exchanger, which is suitable for a liquid metal fast reactor accident residual heat removal system, characterized in that: It includes: A shell, a liquid metal delivery component, and a liquid metal flow pipeline, wherein the liquid metal delivery component is fixedly connected to the shell, and the liquid metal flow pipeline is fixedly connected to the liquid metal delivery component. an air flow component, the air flow component being fixedly connected to the housing, The liquid metal delivery assembly is configured such that liquid metal from the liquid metal fast reactor flows into the liquid metal delivery assembly, exchanges heat with air in the shell through the liquid metal flow pipeline, and then flows out of the liquid metal delivery assembly; The air flow component is configured to allow air from outside to enter the shell and to flow out of the shell after exchanging heat with the liquid metal; The liquid metal flow pipeline is configured to reduce the probability of leakage and improve the heat exchange efficiency of the heat exchanger.

2. The heat exchanger according to claim 1, characterized in that The liquid metal flow pipeline is configured to have fins formed on its surface, and the liquid metal flow pipeline is configured to be bendably arranged on the liquid metal conveying component.

3. The heat exchanger according to claim 2, characterized in that The liquid metal flow pipeline is formed in the following manner: welding fins along a first predetermined length of the liquid metal flow conduit along a first direction, After the welding is completed, the fins are welded along the second direction on the second predetermined length of the portion of the liquid metal flow pipeline where the fins are not welded. A pipeline of a third predetermined length is reserved between the two parts of the liquid metal flow pipeline of the welded fin, and is bendable.

4. The heat exchanger according to claim 3, characterized in that The bending radius of the bend is determined according to heat exchange requirements.

5. The heat exchanger according to claim 3, characterized in that The size and quantity of the fins are determined according to heat exchange requirements.

6. The heat exchanger according to any one of claims 1 to 5, characterized in that: The liquid metal delivery assembly comprises an input current collector and an output current collector, The input current collector and the output current collector are respectively arranged to be fixedly connected to the housing, Liquid metal from the liquid metal fast reactor flows in from the input collector, exchanges heat with the air in the shell through the liquid metal flow pipeline, and then flows out from the output collector. And the liquid metal flow pipeline is fixedly connected to the input collector and the output collector respectively.

7. The heat exchanger according to claim 1, characterized in that The air flow assembly includes a damper, a chimney and a flow distribution member. The damper is arranged at the inlet of the housing, and air from the outside enters the housing through the damper. The flow distribution member is disposed in the housing and is configured to adjust the flow of the air entering through the damper. A chimney is arranged at the outlet of the shell so that the air after heat exchange is discharged from the shell.

8. The heat exchanger according to any one of claims 1 to 7, characterized in that: It also includes a support member, which is arranged on the shell and is configured to support and position the liquid metal flow pipeline and prevent the liquid metal flow pipeline from experiencing flow-induced vibration.

9. The heat exchanger according to claim 8, characterized in that The structure of the support member is determined according to the liquid metal flow pipeline and flow-induced vibration.

10. A liquid metal fast reactor accident residual heat removal system, characterized in that: It comprises the heat exchanger according to any one of claims 1 to 9.

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