Waste heat removal system and waste heat removal method suitable for liquid metal cooling reactor

Abstract

The embodiment of the invention relates to the technical field of nuclear reactors, in particular to a waste heat removal system and a waste heat removal method suitable for a liquid metal cooling reactor. The residual heat removal system comprises an additional shell, an air door and an exhaust chimney, the additional shell is used for wrapping a coolant pipeline or equipment of a primary / secondary loop main cooling system outside a reactor container of the reactor, and a cooling space is formed between the additional shell and the coolant pipeline or equipment; the additional shell is provided with an air inlet pipeline and an air outlet pipeline which are in fluid communication with the cooling space; the air inlet pipeline and each air outlet pipeline are respectively provided with an air door; the exhaust chimney is in fluid communication with the air outlet pipeline, and when the air door is opened, air in the external environment can enter the cooling space through the air inlet pipeline, flows into the exhaust chimney through the air outlet pipeline after being heated and finally flows into the external environment. According to the embodiment of the invention, the residual heat of the primary / secondary loop main cooling system can be passively discharged by utilizing natural flowing of air.

Description

Technical Field

[0001] Embodiments of the present application relate to the field of nuclear reactor technology, and in particular to a waste heat removal system and a waste heat removal method suitable for a liquid metal cooled reactor. Background Art

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

[0003] After a nuclear reactor is shut down, the residual heat generated by the core is very significant due to the residual fission and decay of fission products in the core. Therefore, a special residual heat removal system is required to remove the heat from the core.

[0004] The main function of the accident waste heat removal system of the liquid metal cooled reactor is to remove the waste heat from the reactor under accident conditions (main pump shutdown, plant power outage, earthquake, etc.) when the reactor's main heat transfer system completely loses its heat removal capability.

[0005] At present, there are still many problems in the accident waste heat removal system, which affects the safety of nuclear reactors. Summary of the invention

[0006] 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.

[0007] The first aspect of an embodiment of the present application provides a waste heat removal system suitable for a liquid metal cooled reactor, which includes multiple additional shells, multiple dampers and an exhaust chimney. Each additional shell is used to cover the coolant pipeline or equipment of the one-loop / two-loop main cooling system outside the reactor vessel, so that a cooling space for air flow can be formed between the additional shell and the coolant pipeline or equipment. Each additional shell is provided with an air inlet pipeline and an air outlet pipeline connected to the fluid of the cooling space; each air inlet pipeline and each air outlet pipeline is respectively provided with a damper to control the on-off of the pipeline; the exhaust chimney is connected to the fluid of the air outlet pipeline; wherein, when the dampers on the air inlet pipeline and the air outlet pipeline are opened, the air from the external environment can enter the corresponding cooling space through the air inlet pipeline, and after being heated in the cooling space, flow into the exhaust chimney through the air outlet pipeline and finally flow into the external environment.

[0008] A second aspect of an embodiment of the present application provides a waste heat removal method applicable to a liquid metal cooled reactor, which is implemented using the waste heat removal system provided by the first aspect of an embodiment of the present application.

[0009] The embodiments of the present application provide a waste heat removal system and a waste heat removal method suitable for a liquid metal cooled reactor, which do not require the layout of complex pipelines and can use the air in the external environment in a passive manner to carry the heat of the primary main cooling system and / or the secondary main cooling system to the external environment, and have good passive safety. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0011] Figure 1 It is a schematic diagram of the principle of using the waste heat removal system provided in the embodiment of the present application to remove heat from the coolant pipeline of the primary / secondary circuit main cooling system;

[0012] Figure 2 It is a schematic diagram of the principle of using the waste heat removal system provided in the embodiment of the present application to remove heat from the equipment of the primary / secondary circuit main cooling system;

[0013] Figure 3 It is a schematic diagram of the principle of removing heat from multiple coolant pipelines and / or multiple cooling devices using the waste heat removal system provided by an embodiment of the present application;

[0014] Figure 4 It is a partial structural schematic diagram of using the waste heat removal system provided in the embodiment of the present application to remove heat from the coolant pipeline;

[0015] Figure 5 It is a schematic diagram of the principle of using the waste heat removal system provided in an embodiment of the present application to remove heat from the coolant pipeline in sections.

[0016] It should be noted that the drawings are not necessarily drawn to scale, but are merely shown in a schematic manner that does not affect the reader's understanding.

[0017] Explanation of the reference numerals: 11. coolant pipeline; 12. equipment; 21. additional shell; 22. cooling space; 221. cooling sub-space; 23. air inlet pipeline; 24. air outlet pipeline; 25. damper; 26. exhaust chimney; 27. air outlet main pipe; 28. air inlet main pipe; 29. ​​insulation layer. DETAILED DESCRIPTION

[0018] 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.

[0019] 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.

[0020] 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.

[0021] In the related art, the accident waste heat removal system needs to add additional systems or equipment on the basis of the original main heat transmission system, and cannot rely entirely on passive means.

[0022] In view of the above problems, the embodiments of the present application provide a waste heat removal system suitable for a liquid metal cooled reactor, see Figure 1 to Figure 2 , Figure 1 This is a schematic diagram of the principle of using the waste heat removal system provided by an embodiment of the present application to remove heat from the coolant pipeline of the primary / secondary circuit main cooling system. Figure 2The schematic diagram is a principle diagram of using the waste heat removal system provided by the embodiment of the present application to remove heat from the equipment of the primary / secondary circuit main cooling system, and the arrows in the figure indicate the direction of air flow. The waste heat removal system provided by the embodiment of the present application includes a plurality of additional shells 21, a plurality of dampers 25 and an exhaust chimney 26, each of which is used to cover the coolant pipeline 11 or equipment 12 of the primary / secondary circuit main cooling system outside the reactor vessel, so that a cooling space 22 for air flow can be formed between the additional shell 21 and the coolant pipeline 11 or the equipment 12. Each additional shell 21 is provided with an air inlet pipeline 23 and an air outlet pipeline 24 in fluid communication with the cooling space 22; each air inlet pipeline 23 and each air outlet pipeline 24 are respectively provided with a damper 25 to control the on and off of the pipeline. The exhaust chimney 26 is in fluid communication with the air outlet pipeline 24. When the dampers 25 on the air inlet duct 23 and the air outlet duct 24 are opened, air from the external environment can enter the corresponding cooling space 22 through the air inlet duct 23, and after being heated in the cooling space 22, flow into the exhaust chimney 26 through the air outlet duct 24, and finally flow into the external environment.

[0023] After the air in the cooling space 22 is heated by the coolant pipeline 11 or the device 12, its density decreases, so that it spontaneously flows upward along the air outlet pipeline 24 into the exhaust chimney 26, and finally flows into the external environment. In this process, the air in the external environment can automatically flow into the cooling space 22 via the air intake pipeline 23, thereby establishing a natural circulation flow of air. It can be seen that the waste heat removal system provided by the embodiment of the present application can use the air in the external environment in a passive manner to carry the heat of the primary cooling system and / or the secondary cooling system outside the reactor vessel to the external environment without the need to arrange expensive systems or equipment, and has good passive safety.

[0024] In some embodiments, the coolant in the coolant pipe 11 may be a liquid metal coolant, such as liquid sodium or liquid lead-bismuth alloy.

[0025] It is easy to understand that the additional shell 21, in addition to forming the cooling space 22 together with the coolant pipeline 11 or the equipment 12, can also play a certain isolation role when the coolant pipeline 11 is broken. For a sodium-cooled fast reactor, it can also prevent the occurrence of sodium fire reaction. At the same time, the additional shell 21 can also ensure the integrity and safety of the pressure boundary of the coolant.

[0026] In some embodiments, the damper 25 can be set to be in a closed state under normal operating conditions to prevent air from the external environment from entering the cooling space 22 and taking away heat from the coolant pipeline 11 or the equipment 12.

[0027] If the coolant temperature in the coolant pipeline 11 is too low, the coolant will solidify. Therefore, under normal operating conditions, the air can be enclosed in the cooling space 22 by closing the damper 25. Since the thermal conductivity of the air itself is very low, the heat loss in the coolant pipeline 11 can be reduced.

[0028] In some embodiments, the damper 25 can be set to be in an open state under an accident condition, so that air from the external environment can enter the cooling space 22 to remove heat from the coolant pipeline 11 or the equipment 12.

[0029] In some embodiments, the waste heat removal system of the embodiment of the present application may further include a control component, and the control component is used to control the opening and closing of the damper 25.

[0030] The control component can be connected to the external sensor for communication so as to receive the accident signal sent by the external sensor, thereby controlling the damper 25 to open after receiving the accident information.

[0031] The external sensor may be a temperature sensor for detecting the coolant temperature of the primary cooling system or the secondary cooling system. When the coolant temperature detected by the temperature sensor is higher than a preset threshold, it indicates that an accident condition may have occurred, and the residual heat in the coolant pipeline 11 or the device 12 cannot be discharged in time. At this time, the control component sends a signal to the switch of the damper 25 to open the damper 25 to discharge the residual heat of the coolant pipeline 11.

[0032] In some embodiments, the opening of the damper 25 can be adjusted. By adjusting the opening of the damper 25, the flow rate of air entering the cooling space 22 can be adjusted, thereby adjusting the heat dissipation of the air to the coolant pipeline 11 and the equipment 12.

[0033] In some embodiments, the control component can control the opening of the damper 25 according to the coolant temperature detected by the temperature sensor. When the damper 25 is opened, the control component obtains the coolant temperature in the primary circuit main cooling system or the secondary circuit main cooling system. When the obtained coolant temperature rise rate exceeds the rising set threshold, the control component controls the damper 25 to increase the damper opening; when the obtained coolant temperature drop rate exceeds the falling set threshold, the control component controls the damper 25 to reduce the damper opening.

[0034] See also Figure 3 and Figure 4 , Figure 3 is a schematic diagram of the principle of removing heat from multiple coolant pipelines and / or multiple cooling devices using the waste heat removal system provided by an embodiment of the present application. Figure 4It is a partial structural schematic diagram of the heat removal of the coolant pipeline by the waste heat removal system provided in the embodiment of the present application. In this embodiment, the waste heat removal system also includes an air outlet main pipe 27, and each air outlet pipeline 24 is fluidly connected to the exhaust chimney 26 through the air outlet main pipe 27. The air heated in the cooling space 22 enters the air outlet main pipe 27 through the air outlet pipeline 24, and finally enters the exhaust chimney 26 and flows into the external environment. The air flowing out of multiple air outlet pipelines 24 is aggregated through the air outlet main pipe 27, which is conducive to reducing the flow pressure drop of the air in the cooling space 22, is conducive to the natural circulation of the air, and can also simplify the layout of the pipeline.

[0035] Similarly, in some embodiments, the waste heat removal system may further include an intake manifold 28 , one end of which is an open end connected to the external environment so that air from the external environment can enter the intake manifold 28 ; each air intake pipe 23 is fluidically connected to the intake manifold 28 .

[0036] In some embodiments, the air intake manifold 28 may be disposed below the air outlet manifold 27. The inventor of the present application has found that such a configuration is conducive to the flow of air, so as to enhance the heat dissipation effect of the waste heat removal system.

[0037] In some embodiments, the gas outlet manifold 27 and the gas inlet manifold 28 may be disposed on the top of the reactor building to avoid blockage of the personnel maintenance passage.

[0038] In some embodiments, the waste heat removal system further includes a heat-insulating layer 29 , which is coated on the outside of the additional outer shell 21 and is used to keep the additional outer shell 21 warm.

[0039] As mentioned above, under normal working conditions, the temperature of the coolant needs to be kept above the melting point. To this end, by providing the insulation layer 29, the heat dissipation of the system under normal working conditions can be reduced. The insulation layer 29 can be made of a material with low thermal conductivity.

[0040] The coolant pipeline 11 in the secondary circuit main cooling system is relatively long. If only one air inlet pipeline 23 and one air outlet pipeline 24 are used to dissipate heat therefrom, the resistance to air circulation is large, which is not conducive to achieving natural circulation of air.

[0041] like Figure 5 As shown, Figure 5It is a schematic diagram of the principle of using the waste heat removal system provided in the embodiment of the present application to remove heat from the coolant pipeline in sections. In some embodiments, the additional shell 21 covering the coolant pipeline 11 can be provided with multiple air inlet pipelines 23 and multiple air outlet pipelines 24 at intervals along its length direction, so that the cooling space 22 forms multiple cooling sub-spaces 221 arranged in parallel in multiple sections along the length direction of the coolant pipeline 11. In such an embodiment, since a long coolant pipeline 11 is divided into multiple sections, each section of the coolant pipeline 11 is cooled separately by means of segmented heat dissipation, so as to reduce the flow pressure drop of the air in the air outlet pipeline 24 and the cooling space 22, so as to improve the cooling efficiency.

[0042] The embodiments of the present application also provide a waste heat removal method applicable to a liquid metal cooled reactor, which is implemented using the waste heat removal system provided by any embodiment of the present application. The waste heat removal method provided by the embodiments of the present application does not require the deployment of expensive safety-level systems or equipment, and can use the air in the external environment to carry the heat of the primary cooling system and / or the secondary cooling system to the external environment in a passive manner, and has good passive safety.

[0043] The following describes the method of using the waste heat removal system provided by the present application in conjunction with specific embodiments.

[0044] Under normal working conditions, each damper 25 is opened, and argon gas is input into the cooling space 22 formed between the coolant pipeline 11 of the primary / secondary circuit main cooling system or the equipment 12 and the additional housing 21 through the air intake pipeline 23. After the cooling space 22 is filled with argon gas, each damper 25 is closed. At this time, the argon gas and the additional housing 21 jointly prevent the occurrence of sodium fire reaction, and the argon gas and the insulation layer 29 jointly prevent the loss of heat of the coolant of the primary / secondary circuit main cooling system.

[0045] Under accident conditions, the control component receives a signal from the temperature sensor that the temperature of the coolant in the primary / secondary circuit main cooling system is higher than a preset threshold value, and sends an opening signal to the damper 25. The damper 25 opens, and the density of the argon gas filled in the cooling space 22 decreases after being heated, and the argon gas flows into the exhaust chimney 26 along the air outlet pipe 24. At this time, the air in the external environment spontaneously flows into the cooling space 22 along the air inlet pipe 23. After being heated, the air continues to be collected to the outlet main pipe along the air outlet pipe 24, and then flows into the exhaust chimney 26, and finally enters the external environment, thereby establishing a natural circulation of air among the external environment, the air inlet main pipe 28, the air inlet pipe 23, the cooling space 22, the air outlet pipe 24, the air outlet main pipe 27, the exhaust chimney 26, and the external environment, thereby continuously removing the residual heat in the coolant in the primary / secondary circuit main cooling system to avoid accidents.

[0046] 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.

[0047] 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 waste heat removal system suitable for a liquid metal cooled reactor, characterized in that: include: A plurality of additional shells, each of which is used to enclose the coolant pipeline or equipment of the primary / secondary circuit main cooling system outside the reactor vessel, so that a cooling space for air flow can be formed between the additional shells and the coolant pipeline or equipment, and each of the additional shells is provided with an air inlet pipeline and an air outlet pipeline in fluid communication with the cooling space; A plurality of dampers, each of the air inlet pipeline and each of the air outlet pipeline is respectively provided with one damper to control the on-off of the pipeline; an exhaust chimney in fluid communication with the air outlet pipeline; Among them, when the dampers on the air inlet pipe and the air outlet pipe are opened, the air from the external environment can enter the corresponding cooling space through the air inlet pipe, and after being heated in the cooling space, flow into the exhaust chimney through the air outlet pipe, and finally flow into the external environment.

2. The waste heat removal system according to claim 1, characterized in that: The damper is configured to be in a closed state under normal working conditions to prevent air from the external environment from entering the cooling space and taking away heat from the coolant pipeline or equipment.

3. The waste heat removal system according to claim 1, characterized in that: The damper is configured to be in an open state under an accident condition so that air from the external environment can enter the cooling space and remove heat from the coolant pipeline or equipment.

4. The waste heat removal system according to claim 1, characterized in that: Also includes: An air outlet main pipe, each of the air outlet pipes is fluidly connected to the exhaust chimney through the air outlet main pipe, and the air heated in the cooling space enters the air outlet main pipe through the air outlet pipes, and finally enters the exhaust chimney and flows into the external environment.

5. The waste heat removal system according to claim 4, characterized in that: Also includes: An air intake manifold, one end of which is an open end and communicates with the external environment so that air from the external environment can enter the air intake manifold; Each of the air intake lines is in fluid communication with the intake manifold.

6. The waste heat removal system according to claim 5, characterized in that: The air intake manifold is arranged below the air outlet manifold.

7. The waste heat removal system according to claim 5, characterized in that: The gas outlet main pipe and the gas inlet main pipe are arranged on the top of the reactor building.

8. The waste heat removal system according to claim 1, characterized in that: Also includes: The heat-insulating layer is coated on the outer side of the additional outer shell and is used for heat-insulating the additional outer shell.

9. The waste heat removal system according to claim 1, characterized in that: The additional shell covering the coolant pipeline is provided with a plurality of air inlet pipelines and a plurality of air outlet pipelines at intervals along its length direction, so that the cooling space forms a plurality of cooling sub-spaces arranged in parallel in multiple sections along the length direction of the coolant pipeline.

10. A method for removing waste heat from a liquid metal cooled reactor, characterized in that: This is achieved by using the waste heat removal system described in any one of claims 1 to 9.

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