Residual heat removal system of reactor

Abstract

The embodiment of the invention relates to the field of removal of shutdown waste heat, in particular to a waste heat removal system of a reactor, the reactor comprises a secondary loop, a steam generator and a steam-water separator, the steam generator and the steam-water separator are arranged in the secondary loop, and steam flowing out of the steam generator enters the steam-water separator for steam-water separation. The waste heat discharging system comprises a steam leading-out pipeline, a cooling medium container, a heat exchanger and a steam leading-back pipeline. A cooling medium is contained in the cooling medium container; the heat exchanger is arranged in the cooling medium container; the steam leading-out pipeline is used for communicating the steam-water separator with the heat exchanger, so that steam in the steam-water separator flows to the heat exchanger, and the steam is cooled by a cooling medium in the heat exchanger to form condensed water; and the steam return pipeline is used for enabling the condensate water in the heat exchanger to return to the steam generator under the action of gravity. The waste heat removal system provided by the embodiment of the invention can passively remove the waste heat in the secondary loop, and is safe and reliable.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of removing shutdown residual heat, and in particular to a residual heat removal system for a 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 reactor is shut down due to an accident, the reactor core will still generate a large amount of decay heat, which is called residual heat. If the residual heat cannot be discharged from the reactor in time, the residual heat will continue to accumulate in the reactor, which will bring risks to the safety of the reactor and pose safety hazards. Therefore, it is necessary to discharge the residual heat from the reactor.

[0004] Currently, water injection or ventilation is usually adopted to discharge the waste heat of the reactor. However, water injection or ventilation usually involves modification of the reactor, which may affect the core and reactor vessel, and thus may bring risks to the safety of the reactor. Summary of the invention

[0005] 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.

[0006] In the related art, in order to reduce the impact on the reactor core, water can be added to the steam generator of the secondary circuit through a pump to discharge the residual heat of the reactor. However, this residual heat discharge method is active, requiring the relevant active equipment to reliably perform its function when the system is activated, and has high requirements on the reliability of the active equipment and the supporting conditions for the operation of the system, which greatly increases the complexity and construction cost of the system.

[0007] In view of the above problems, an embodiment of the present application provides a waste heat removal system for a reactor, wherein the reactor includes a secondary circuit and a steam generator and a steam-water separator arranged in the secondary circuit, wherein the steam carrying liquid water flowing out of the steam generator enters the steam-water separator for steam-water separation. The waste heat removal system provided by an embodiment of the present application includes a steam lead-out pipeline, a cooling medium container, a heat exchanger and a steam return pipeline. The cooling medium container contains a cooling medium; the heat exchanger is arranged in the cooling medium container; the steam lead-out pipeline is used to connect the steam-water separator and the heat exchanger, so that the steam in the steam-water separator flows to the heat exchanger, thereby using the cooling medium in the heat exchanger to cool the steam to form condensed water; the steam return pipeline is used to return the condensed water in the heat exchanger to the steam generator under the action of gravity.

[0008] The waste heat discharge system provided in the embodiments of the present application is configured by arranging a heat exchanger in a cooling medium container and arranging a steam outlet pipeline for connecting a steam-water separator and the heat exchanger, so that the steam in the steam-water separator can passively enter the heat exchanger to exchange heat with the cooling medium, and the formed condensed water can return to the steam generator under the action of gravity, thereby safely and reliably discharging the waste heat in the secondary circuit in a passive manner.

[0009] In addition, the embodiment of the present application is beneficial to improving the cooling effect of the cooling medium on the steam by disposing the heat exchanger in the cooling medium container containing the cooling medium, thereby improving the waste heat removal effect of the reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Other objects and advantages of the present application will become apparent from the following description of the embodiments of the present application with reference to the accompanying drawings, and will help to provide a comprehensive understanding of the present application.

[0011] Figure 1 It is a schematic diagram of the structure of the waste heat removal system provided in the embodiment of the present application.

[0012] Description of reference numerals:

[0013] 100. Waste heat removal system;

[0014] 10. Steam outlet pipe; 20. Cooling medium container; 21. Evaporation port; 22. Liquid replenishment port; 23. Overflow port; 24. Liquid discharge port;

[0015] 30. heat exchanger; 31. heat exchange tube; 40. steam return pipeline; 50. flow regulator; 60. cooling circuit; 601. coolant inlet; 602. coolant outlet;

[0016] 101. Cooling medium liquid level;

[0017] 200. Secondary circuit; 210. Steam-water separator; 220. Steam generator.

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

[0019] 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.

[0020] 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.

[0021] An embodiment of the present application provides a waste heat removal system for a reactor, wherein the reactor may include a secondary circuit and a steam generator and a steam-water separator arranged in the secondary circuit, wherein steam carrying liquid water flowing out of the steam generator can enter the steam-water separator for steam-water separation.

[0022] See also Figure 1 The waste heat removal system 100 provided in the embodiment of the present application may include a steam lead-out pipeline 10, a cooling medium container 20, a heat exchanger 30 and a steam return pipeline 40. The cooling medium container 20 contains a cooling medium; the heat exchanger 30 is arranged in the cooling medium container 20; the steam lead-out pipeline 10 is used to connect the heat exchanger 30 with the steam-water separator 210, so that the steam in the steam-water separator 210 flows to the heat exchanger 30, so that the cooling medium is used to cool the steam in the heat exchanger 30 to form condensed water; the steam return pipeline 40 is used to return the condensed water in the heat exchanger 30 to the steam generator 220 under the action of gravity.

[0023] The waste heat removal system 100 provided in the embodiment of the present application is configured by arranging a heat exchanger 30 in the cooling medium container 20, and arranging a steam outlet pipeline 10 for connecting the steam-water separator 210 and the heat exchanger 30, so that the steam in the steam-water separator 210 can passively enter the heat exchanger 30 to exchange heat with the cooling medium, and the formed condensed water can return to the steam generator 220 under the action of gravity, thereby safely and reliably discharging the waste heat in the secondary circuit 200 to the cooling medium of the cooling medium container 20 in a passive manner.

[0024] In addition, the embodiment of the present application is beneficial to improving the cooling effect of the cooling medium on the steam by disposing the heat exchanger 30 in the cooling medium container 20 containing the cooling medium, thereby improving the waste heat removal effect of the reactor.

[0025] In some embodiments, the reactor may be a lead-bismuth reactor. In some embodiments, the cooling medium may be water at room temperature, and the cooling medium container 20 may be a water tank.

[0026] In some embodiments, an air cavity is formed inside the steam-water separator 210 above the liquid surface of the liquid phase water, and the steam outlet pipe 10 is connected to the air cavity. The steam in the air cavity can directly flow into the steam outlet pipe 10 and enter the heat exchanger 30.

[0027] The steam outlet pipeline 10 is configured to enable the steam-water separator 210 and the heat exchanger 30 to maintain communication, so that the steam in the steam-water separator 210 can directly enter the steam outlet pipeline 10 and flow to the heat exchanger 30. Specifically, no other components such as valves that can change the state of the pipeline are provided on the steam outlet pipeline 10, so that the steam outlet pipeline 10 and the heat exchanger 30 are always connected; or, other components such as valves that can change the state of the pipeline are provided on the steam outlet pipeline, but the other components are always kept in a state of allowing the pipeline to flow, so that the steam-water separator 210 and the heat exchanger 30 are always connected.

[0028] See also Figure 1 In some embodiments, the waste heat removal system 100 may further include a flow regulator 50, which is disposed in the steam return line 40 and is used to automatically adjust the flow of condensed water returning from the steam return line 40 to the steam generator 220 according to the pressure in the heat exchanger 30.

[0029] In an embodiment of the present application, since the steam-water separator 210 and the heat exchanger 30 remain connected, the flow regulating component 50 automatically adjusts the flow rate of condensed water returning from the steam return pipe 40 to the steam generator 220 according to the pressure in the heat exchanger 30, so that the flow regulating component 50 can automatically adjust the height of the gas-liquid separation interface in the heat exchanger 30 (i.e., the liquid level of the condensed water), thereby adjusting the heat exchange capacity of the heat exchanger 30, thereby realizing the adjustment of the heat removal capacity of the entire waste heat removal system 100.

[0030] Specifically, under normal operating conditions, the steam in the steam generator 220 can automatically flow into the heat exchanger 30 for heat exchange, and the condensed water formed by the heat exchange returns to the steam generator 220 via the steam return line 40. When the steam in the steam generator 220 increases (especially in the accident condition of the reactor, when the coolant temperature in the reactor is high), the steam in the steam-water separator 210 increases accordingly, so that the gas pressure in the heat exchanger 30 increases. At this time, the condensed water level in the heat exchanger 30 drops, and the heat exchange area of ​​the steam increases. Since the flow regulator 50 of the embodiment of the present application can automatically adjust the flow of the condensed water returning from the steam return line 40 to the steam generator 220 according to the pressure in the heat exchanger 30, when the gas pressure in the heat exchanger 30 increases, the flow regulator 50 can automatically increase the flow of the condensed water flowing from the heat exchanger 30 through the steam return line 40 to the steam generator 220, which is conducive to accelerating the condensation of the steam in the steam-water separator 210 and accelerating the discharge of the residual heat of the reactor.

[0031] In some embodiments, the flow regulating member 50 can automatically adjust its opening according to the pressure in the heat exchanger 30, so as to automatically adjust the flow rate of the condensed water returning to the steam generator 220 according to the pressure in the heat exchanger 30. Since the flow regulating member 50 is arranged in the steam return pipeline 40, when it adjusts its opening, the flow rate of the condensed water in the steam return pipeline 40 returning to the steam generator 220 is adjusted, the height of the gas-liquid separation interface in the heat exchanger 30 is changed, and the heat exchange capacity of the heat exchanger 30 is adjusted.

[0032] In some embodiments, the flow regulating member 50 has an opening pressure. When the pressure in the heat exchanger 30 does not reach the opening pressure, the pressure change in the heat exchanger 30 cannot change the opening of the flow regulating member 50, and the flow regulating member 50 is not opened first. In this process, after the steam entering the heat exchanger 30 is cooled into condensed water, the condensed water becomes more and more, gradually filling the entire heat exchange space of the heat exchanger 30. Since the steam cannot enter the heat exchange space of the heat exchanger 30, it cannot temporarily exchange heat with the cooling medium. As the steam becomes more and more, the pressure in the heat exchanger 30 becomes greater and greater. After reaching the opening pressure, the flow regulating member 50 is opened, and the condensed water level in the heat exchanger 30 begins to drop, so that the steam can enter the heat exchange space to exchange heat with the cooling medium. The condensed water returns to the steam generator 220 through the steam return pipeline 40 under the action of gravity, and the waste heat removal system 100 begins to discharge heat.

[0033] In some embodiments, the flow regulating member 50 also has a full-open pressure. When the pressure in the heat exchanger 30 reaches the full-open pressure, the opening of the flow regulating member 50 reaches the maximum opening and remains at the maximum opening.

[0034] In the embodiment of the present application, the greater the pressure in the steam-water separator 210 , the greater the opening of the flow regulating member 50 , and the waste heat removal capacity of the waste heat removal system 100 also increases accordingly.

[0035] In some embodiments, the opening pressure and the full opening pressure of the flow regulating member 50 can be set according to the specific needs of waste heat removal.

[0036] In some embodiments, the flow regulating member 50 may include an elastic member, a liquid flow channel, and a shielding member for adjusting the opening of the liquid flow channel. The elastic member is configured to be deformed under the pressure in the heat exchanger 30, thereby driving the shielding member to move to adjust the opening of the liquid flow channel (i.e., the opening of the flow regulating member 50). In such an embodiment, the flow rate of the condensed water flowing through can be adjusted by adjusting the opening of the liquid flow channel, so that the flow rate of the condensed water can be automatically adjusted according to the pressure in the heat exchanger 30.

[0037] In some embodiments, when the pressure in the heat exchanger 30 does not reach the opening pressure, the elastic member may not deform, or even if the elastic member can still deform under the pressure in the heat exchanger 30, the shielding member still blocks the liquid flow channel and the flow regulating member 50 does not open.

[0038] In some embodiments, the elastic member may be a spring.

[0039] In some embodiments, when the elastic member is a spring, the elastic coefficient of the spring can be set according to the specific needs of the waste heat discharge. Since the elastic coefficient of the spring is related to the degree of deformation of the spring when facing pressure, the opening of the liquid flow channel can be set by setting the elastic coefficient of the spring, thereby setting the opening pressure and full opening pressure of the flow regulating member 50.

[0040] See also Figure 1 In some embodiments, the steam return pipe 40 is located below the heat exchanger 30, and the steam return pipe 40 is also located above the steam generator 220. The condensed water in the heat exchanger 30 can flow into the steam generator 220 through the steam return pipe 40 under the action of gravity. In such an embodiment, since the position of the heat exchanger 30 is higher than that of the steam generator 220, the condensed water in the heat exchanger 30 can be smoothly returned to the steam generator 220 passively under the action of its own gravitational potential energy, and the structure is simple and safe and reliable. During the operation of the waste heat removal system 100, the adjustment action of the flow regulating member 50 is completely passively performed by relying on the pressure in the system and the potential difference in the arrangement of the heat exchanger 30 and the steam-water separator 210.

[0041] See also Figure 1 Since steam can flow on its own, in some embodiments, the steam generator 220 can be located below the steam-water separator 210; the heat exchanger 30 can be located above the steam-water separator 210, thereby increasing the height difference between the heat exchanger 30 and the steam generator 220, which is more conducive to the condensed water returning to the steam generator 220 via the steam return pipe 40.

[0042] See also Figure 1 In some embodiments, the heat exchanger 30 may include a plurality of heat exchange tubes 31, each of which is located in the cooling medium container 20 and contacts the cooling medium for heat exchange. In such an embodiment, the heat exchange tube 31 directly contacts the cooling medium for heat exchange, which is beneficial to improve the heat exchange effect between the heat exchange tube 31 and the cooling medium.

[0043] See also Figure 1 In some embodiments, the heat exchanger 30 is located below the cooling medium liquid level 101 in the cooling medium container 20. In such an embodiment, it is beneficial to increase the heat exchange area between the heat exchanger 30 and the cooling medium, thereby facilitating the cooling effect of the cooling medium on the steam in the heat exchanger 30.

[0044] See also Figure 1In some embodiments, the waste heat removal system 100 may further include a cooling circuit 60 for cooling the cooling medium in the cooling medium container 20. When the cooling medium cools the steam in the heat exchanger 30, the temperature of the cooling medium itself will increase, thereby causing the cooling effect of the cooling medium on the steam to decrease. In such an embodiment, cooling the cooling medium in the cooling medium container 20 through the cooling circuit 60 is conducive to ensuring the heat exchange effect between the cooling medium and the steam.

[0045] In some embodiments, part of the pipeline in the cooling circuit 60 is located below the cooling medium liquid level 101 in the cooling medium container 20, so as to utilize the external coolant flowing therein to exchange heat with the cooling medium in the cooling medium container 20. In some embodiments, the coolant can be cooling water from a process cooling water system outside the waste heat removal system 100.

[0046] See also Figure 1 In some embodiments, the cooling circuit 60 is provided with a coolant inlet 601 and a coolant outlet 602, and the coolant inlet 601 and the coolant outlet 602 are connected to the process cooling water system. The cooling water from the process cooling water system can enter the cooling circuit 60 through the coolant inlet 601 to exchange heat with the cooling medium. After the heat exchange is completed, the cooling water can flow back from the cooling circuit 60 to the process cooling water system through the coolant outlet 602.

[0047] In some embodiments, the cooling circuit 60 and the heat exchanger 30 are disposed on both sides of the cooling medium container 20 so that the cooling medium in the cooling medium container 20 can circulate naturally by utilizing the temperature difference between the two. In such an embodiment, the heat of the steam in the heat exchanger 30 can be transferred to the cooling circuit 60 through the natural circulation of the cooling medium, and finally the heat of the steam is taken away from the waste heat removal system 100 by the cooling circuit 60.

[0048] In some embodiments, cooling loop 60 may carry heat from the steam within steam generator 220 to the ultimate heat sink of the reactor.

[0049] In some embodiments, the cooling medium container 20 is provided with an evaporation port 21 so that the cooling medium in the cooling medium container 20 can be cooled by evaporation. In such an embodiment, when the cooling circuit 60 fails and the cooling medium in the cooling medium container 20 cannot be cooled by the cooling circuit 60, the cooling medium in the cooling medium container 20 can be cooled by evaporation to discharge the heat of the steam.

[0050] In some embodiments, when the cooling circuit 60 fails and the cooling medium uses evaporation to cool down, the waste heat removal system 100 operates in a completely passive working mode.

[0051] In some embodiments, the size of the evaporation port 21 can be determined according to the amount of waste heat discharged. For example, when the amount of waste heat discharged is large, the evaporation port 21 can be set to a larger size.

[0052] In some embodiments, the amount of cooling medium in the cooling medium container 20 can be set according to the duration of cooling medium cooling by evaporation. For example, the longer the duration of cooling medium cooling by evaporation, the more cooling medium in the cooling medium container 20.

[0053] See also Figure 1 In some embodiments, the cooling medium container 20 is further provided with a liquid replenishing port 22 to replenish the cooling medium into the cooling medium container 20. In such an embodiment, the cooling medium is replenished into the cooling medium container 20 through the liquid replenishing port 22 to prevent the cooling medium liquid level from being lower than the heat exchanger 30.

[0054] See also Figure 1 In some embodiments, the cooling medium container 20 is further provided with an overflow port 23 for the excess cooling medium in the cooling medium container 20 to flow out. In order to allow the cooling medium in the cooling medium container 20 to cool down by evaporation, the cooling medium in the cooling medium container 20 should not be too much, and space for steam should be reserved. In such an embodiment, when there is too much cooling medium in the cooling medium container 20, it can leave the cooling medium container 20 through the overflow port 23 to ensure that there is space for steam evaporation in the cooling medium container 20.

[0055] See also Figure 1 In some embodiments, the cooling medium container 20 is further provided with a drain port 24 for draining the cooling medium in the cooling medium container 20. In such an embodiment, after the waste heat is discharged, the cooling medium flows out of the cooling medium container 20 through the drain port 24, which is conducive to the recovery of the cooling medium.

[0056] The working process of the waste heat removal system 100 of the embodiment of the present application is described in detail below with reference to the accompanying drawings. When the waste heat removal system 100 starts to work, the steam in the steam generator 220 enters the heat exchanger 30 to form condensed water. As the steam continues to enter, the heat exchanger 30 is filled with condensed water and flows to the steam return pipe 40. At this time, since the heat exchanger 30 is full of condensed water, the pressure does not reach the opening pressure of the flow regulating member 50, the flow regulating member 50 is not opened, and the condensed water remains in the heat exchanger 30 and the steam return pipe 40, and the heat exchange area of ​​the steam is small; afterwards, as the steam continues to enter the heat exchanger 30, the pressure in the heat exchanger 30 continues to increase until it reaches the opening pressure of the flow regulating member 50, the flow regulating member 50 is opened, and the condensed water in the heat exchanger 30 flows back to the steam generator 220 under the action of pressure, causing the condensed water level in the heat exchanger 30 to drop and the heat exchange area of ​​the steam to increase.

[0057] When the waste heat removal system of the embodiment of the present application is put into operation, the secondary circuit steam is extracted from the top of the secondary circuit steam-water separator 210 of the reactor, the steam enters the heat exchanger 30, is cooled, condenses into water and is collected at the bottom of the heat exchanger 30, and naturally flows into the bottom of the steam-water separator 210 by relying on the potential difference between the heat exchanger 30, the steam-water separator 210 and the steam generator 220, thereby flowing into the steam generator 220 through the pipeline of the secondary circuit system and being converted into steam again to remove the core waste heat and then enter the secondary circuit steam-water separator 210, and this cycle is repeated to realize the waste heat removal of the reactor; the discharged waste heat is finally brought to the final heat sink of the reactor through the cooling circuit 60.

[0058] 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.

[0059] 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 for a reactor, the reactor comprising a secondary circuit and a steam generator and a steam-water separator arranged in the secondary circuit, wherein: The steam carrying liquid phase water flowing out of the steam generator enters the steam-water separator for steam-water separation, wherein the waste heat removal system comprises: A cooling medium container containing a cooling medium; a heat exchanger, the heat exchanger being disposed in the cooling medium container; a steam outlet pipeline, used to connect the steam-water separator and the heat exchanger, so that the steam in the steam-water separator flows to the heat exchanger, and the steam is cooled by the cooling medium in the heat exchanger to form condensed water; The steam return pipeline is used to return the condensed water in the heat exchanger to the steam generator under the action of gravity.

2. The waste heat removal system according to claim 1, characterized in that: Also includes: A flow regulating member is provided in the steam return pipeline and is used for automatically regulating the flow of condensed water returning from the steam return pipeline to the steam generator according to the pressure in the heat exchanger.

3. The waste heat removal system according to claim 2, characterized in that: The flow regulating member includes: an elastic member, a liquid flow channel and a shielding member for regulating the opening of the liquid flow channel. The elastic member is configured to be deformed under the pressure in the heat exchanger, thereby driving the shielding member to move to regulate the opening of the liquid flow channel.

4. The waste heat removal system according to claim 1, characterized in that: The steam return pipeline is located below the heat exchanger; The steam return pipeline is located above the steam generator, and the condensed water in the heat exchanger can flow into the steam generator under the action of gravity.

5. The waste heat removal system according to claim 4, characterized in that: The steam generator is located below the steam-water separator; The heat exchanger is located above the steam-water separator.

6. The waste heat removal system according to claim 1, characterized in that: The heat exchanger comprises a plurality of heat exchange tubes, each of which is located in the cooling medium container and contacts with the cooling medium for heat exchange.

7. The waste heat removal system according to claim 1, characterized in that: The heat exchanger is located below the cooling medium liquid level in the cooling medium container.

8. The waste heat removal system according to claim 1, characterized in that: Also includes: The cooling circuit is used to cool the cooling medium in the cooling medium container.

9. The waste heat removal system according to claim 8, characterized in that: The cooling circuit and the heat exchanger are arranged on both sides of the cooling medium container opposite to each other, so that the cooling medium in the cooling medium container can circulate naturally by utilizing the temperature difference between the two.

10. The waste heat removal system according to claim 1, characterized in that: The cooling medium container is provided with an evaporation port so that the cooling medium in the cooling medium container can be cooled by evaporation.

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