A passive residual heat removal device and system for a nuclear power plant

Abstract

The application provides a nuclear power plant passive residual heat removal device and system, which comprises a steam generator, a steam outflow pipe section, a condensation heat exchange assembly, a condensate pipe section, an emergency water supply tank and a water supply pipe section. In the vertical direction, the condensation heat exchange assembly and the emergency water supply tank are arranged above the steam generator. The steam generator and the inlet of the condensation heat exchange assembly are communicated through the steam outflow pipe section, the steam outflow pipe section is provided with a first isolation valve and is configured as always open. The outlet of the condensation heat exchange assembly and the steam generator are communicated through the condensate pipe section, the condensate pipe section is provided with a second isolation valve and is configured as always closed. The top of the emergency water supply tank is communicated between the first isolation valve and the inlet of the condensation heat exchange assembly, the water outlet of the emergency water supply tank and the steam generator are communicated through the water supply pipe section, the water supply pipe section is provided with a third isolation valve. The first liquid level of the water in the emergency water supply tank is lower than the top end surface of the emergency water supply tank.

Description

Technical Field

[0001] This application relates to the technical field of waste heat removal systems for nuclear power plants, and in particular to a passive waste heat removal device and system for nuclear power plants. Background Technology

[0002] In the event of a main feedwater pipeline rupture or a plant-wide power outage at a nuclear power plant, the steam generator loses secondary feedwater, preventing the core heat from being dissipated. This can lead to overheating and overpressure in the reactor coolant system, threatening the safe operation of the nuclear power plant. To effectively address these accident scenarios, an emergency feedwater system using electric pumps is typically employed. However, since electric pumps are still active equipment, this reactive approach may fail during a power outage, thus compromising the safety of the nuclear power plant. Summary of the Invention

[0003] This application provides a passive waste heat removal device and system for nuclear power plants, which solves the problem that emergency water supply systems using active equipment fail to provide emergency water replenishment for nuclear power plants during power outages.

[0004] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0005] In a first aspect, embodiments of this application provide a passive waste heat removal device for a nuclear power plant, comprising: a steam generator, a steam outlet pipe section, a condensate heat exchange assembly, a condensate pipe section, an emergency makeup water tank, and a makeup water pipe section. Vertically, the condensate heat exchange assembly and the emergency makeup water tank are positioned above the steam generator. The inlet of the steam generator is connected to the inlet of the condensate heat exchange assembly via the steam outlet pipe section, which is equipped with a first isolation valve. The outlet of the condensate heat exchange assembly is connected to the steam generator via the condensate pipe section, which is equipped with a first isolation valve. Two isolation valves; the top of the emergency water supply tank is connected between the first isolation valve and the inlet of the condensing heat exchange component, and the bottom of the emergency water supply tank is provided with a water outlet. The water outlet is connected to the steam generator through the water supply pipe section, and the water supply pipe section is provided with a third isolation valve; wherein, when the passive waste heat removal device of the nuclear power plant is in the initial state, the first isolation valve is configured to be normally open, the second isolation valve is configured to be normally closed, and when the emergency water supply tank is filled with water, the first liquid level of the water in the emergency water supply tank is lower than the top surface of the emergency water supply tank.

[0006] In some embodiments, a second isolation valve is provided between the connection point of the water supply pipe section and the condensate pipe section and the steam generator.

[0007] In some embodiments, the emergency water supply tank has the water outlet on its bottom surface.

[0008] In some embodiments, the top of the emergency water supply tank has a first opening and a second opening, the first opening being connected to the steam outlet pipe section and the second opening being connected to the inlet of the condenser heat exchanger; in the vertical direction, the first liquid level in the emergency water supply tank is configured to be lower than the first opening and lower than the second opening.

[0009] In some embodiments, in the vertical direction, the second opening is located on the same horizontal plane as the first opening, or the second opening is higher than the first opening.

[0010] In some embodiments, in the vertical direction, the second opening of the emergency water supply tank is higher than the inlet of the condensing heat exchange assembly; and / or, the condensing heat exchange assembly includes a condensate tank and a condensing heat exchanger, the condensing heat exchanger being disposed in the condensate tank, and the bottom surface of the emergency water supply tank being not lower than the centerline of the condensing heat exchanger in the horizontal direction.

[0011] In some embodiments, the condensing heat exchange assembly includes a condensate tank and a condensing heat exchanger, the condensing heat exchanger being disposed in the condensate tank, the inlet of the condensing heat exchanger being located below the outlet of the condensing heat exchanger, and the inlet and outlet of the condensing heat exchange assembly being the inlet and outlet of the condensing heat exchanger, respectively.

[0012] In some embodiments, the condenser heat exchanger is disposed at the bottom of the condensate tank, and in the vertical direction, the inlet of the condenser heat exchanger is located at the top surface of the condenser heat exchanger, and the outlet of the condenser heat exchanger is located at the bottom surface of the condenser heat exchanger.

[0013] In some embodiments, the condensate tank includes an upper cavity and a lower cavity that are connected in the vertical direction, the condenser heat exchanger is disposed in the lower cavity, the volume of the lower cavity is larger than the volume of the condenser heat exchanger, and the volume of the lower cavity is smaller than the volume of the upper cavity.

[0014] In some embodiments, the area of ​​the lower cavity in the first plane is smaller than the area of ​​the upper cavity in the first plane, and the first plane is a plane perpendicular to the vertical direction.

[0015] In some embodiments, the number of the second isolation valves is one or more.

[0016] In some embodiments, the second isolation valve includes two isolation valves connected in parallel on the condensate pipe section.

[0017] In some embodiments, the number of the third isolation valves is one or more.

[0018] In some embodiments, the third isolation valve includes two isolation valves connected in parallel to the water supply pipe section.

[0019] In some embodiments, the passive residual heat removal device for nuclear power plants further includes a level gauge and a water replenishment controller. The level gauge is mounted on the steam generator and is used to measure the liquid level in the steam generator. The water replenishment controller is electrically connected between the level gauge and the third isolation valve. The water replenishment controller is configured to: open the third isolation valve when the liquid level in the steam generator is lower than a preset value; and close the third isolation valve when the liquid level in the steam generator is equal to or greater than the preset value.

[0020] In some embodiments, the second isolation valve is an electrically operated isolation valve, and the third isolation valve is an electrically operated isolation valve; the passive residual heat removal device of the nuclear power plant further includes a residual heat removal controller, which is electrically connected to the second isolation valve and the third isolation valve.

[0021] In some embodiments, the condensate pipe section is provided with an emergency water supply check valve, which is located between the second isolation valve and the steam generator.

[0022] Secondly, this application also provides a passive waste heat removal system, including a passive waste heat removal device for nuclear power plants as described in the first aspect above. The steam generator in the passive waste heat removal device is also connected to a normal operating circuit for the steam generator. The normal operating circuit for the steam generator includes an outflow pipe and an inflow pipe. The outflow pipe is provided with a fourth isolation valve. The inflow pipe is provided with a fifth isolation valve and a main makeup water check valve. The main makeup water check valve is located between the fifth isolation valve and the steam generator. A makeup water assembly is also provided between the outflow pipe and the inflow pipe.

[0023] The beneficial effects of the passive residual heat removal device for nuclear power plants provided in this application are as follows: Compared with related technologies, this application places the condensing heat exchange assembly and the emergency makeup water tank above the steam generator. The condensing heat exchange assembly provides the cold source, and its inlet is connected to the steam generator via a steam outlet pipe section. The top of the emergency makeup water tank is connected between the first isolation valve on the steam outlet pipe section and the inlet of the condensing heat exchange assembly. The first isolation valve on the steam outlet pipe section is set to normally open. The outlet of the condensing heat exchanger is connected to the steam generator via a condensate pipe section, and the second isolation valve on the condensate pipe section is set to normally closed. Thus, even if the nuclear power plant experiences a complete loss of feedwater accident and is in a power outage condition, when the passive residual heat removal device is working, the steam generated by the steam generator rises through the steam outlet pipe section, passes the top of the emergency makeup water tank, and reaches the inlet of the condensing heat exchange assembly. After being cooled by the condensing heat exchange assembly, it becomes water and returns to the steam generator through the condensate pipe section under gravity. This eliminates the need for... By employing active mechanical means such as electric or steam-driven pumps, passive natural circulation is achieved, allowing the core heat of the steam generator to be smoothly discharged. This not only reduces dependence on power supply, HVAC, and other support systems, thus lowering the probability of system failure due to power outages, but also ensures that the emergency makeup water tank is in a hot standby state, avoiding adverse hydraulic loads caused by steam injecting into the cold water in the emergency makeup water tank during system startup. Furthermore, when the liquid level in the steam generator is low, the opening and closing of the third isolation valve allows water in the emergency makeup water tank to flow out through the bottom outlet under gravity and then automatically replenish the steam generator through the makeup water pipe section, thereby smoothly discharging the core heat from the steam generator. Thus, while ensuring safety functions, the reliability of the residual heat removal system during power outages in nuclear power plants is improved, thereby enhancing the safety of the nuclear power plant. In addition, the structure is simple, easy to arrange, highly controllable, and has high cooling capacity. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a passive waste heat removal system for a nuclear power plant provided in an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the structure of the passive waste heat removal device for nuclear power plants provided in the embodiments of this application;

[0027] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0028] Figure 4 This is a schematic diagram of the connection between the emergency water supply tank and the condenser heat exchanger in some embodiments;

[0029] Figure 5 This is a schematic diagram of the connection between the emergency water supply tank and the condenser heat exchanger in some other embodiments.

[0030] Figure label:

[0031] 1. First isolation valve; 2. Second isolation valve; 3. Third isolation valve; 4. Emergency water supply check valve; 5. Fourth isolation valve; 6. Fifth isolation valve; 7. Main water supply check valve;

[0032] 100. Steam outlet pipe section; 200. Condensate pipe section; 300. Water supply pipe section;

[0033] 10. Steam generator; 20. Emergency water supply tank; 21. First opening; 22. Second opening; 23. Water outlet; 30. Condensation heat exchange assembly; 31. Condensate tank; 301. Upper cavity; 302. Lower cavity; 32. Condensation heat exchanger; 40. Level gauge. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0035] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0036] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation", "connection" and "joining" should be interpreted broadly, for example, as fixed connection, detachable connection, or integral connection; those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0037] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] In the event of a main feedwater pipeline rupture or a plant-wide power outage at a nuclear power plant, the steam generator loses secondary feedwater, preventing the core heat from being dissipated. This can lead to overheating and overpressure in the reactor coolant system, threatening the safe operation of the nuclear power plant. To effectively address these accident scenarios, an emergency feedwater system using electric pumps is typically employed. However, since electric pumps are still active equipment, this reactive approach may fail during a power outage, thus compromising the safety of the nuclear power plant.

[0039] To address the aforementioned issues, some systems currently use steam-driven pumps instead of electric pumps, enabling the secondary side to operate normally during power outages. While this allows for a certain period of operation during power outages, it also presents a problem where, when the liquid level in the steam generator is low (i.e., the water volume is insufficient), the inability to replenish water to the steam generator in time can lead to failure in waste heat discharge.

[0040] To address the problem of residual heat removal failure caused by electric or pneumatic pumps in related technologies under accident conditions, this application provides a passive residual heat removal device and a passive residual heat removal system for nuclear power plants. The passive residual heat removal system for nuclear power plants includes the passive residual heat removal device.

[0041] The aforementioned passive residual heat removal devices and systems for nuclear power plants may be, but are not limited to, passive residual heat removal devices and systems for the secondary side of nuclear power plants.

[0042] Compared to related technologies that include active equipment such as electric pumps for waste heat removal, the passive waste heat removal device and system for nuclear power plants provided in this application are passive natural circulation systems. This system can effectively remove core heat from the steam generator 10 during power outages, specifically after a complete loss of feedwater at the nuclear power plant. This solves the problem in related technologies where emergency feedwater systems using steam-driven pumps fail to provide emergency feedwater during power outages. Furthermore, an emergency feedwater tank 20 is installed on the steam outlet pipe section 100 of the steam generator 10. When necessary, water from the emergency feedwater tank 20 can be supplied to the steam generator 10 via the feedwater pipe section 300, reducing the probability of a nuclear power plant safety accident caused by untimely feedwater supply leading to waste heat removal failure.

[0043] like Figures 1 to 3 As shown, the passive waste heat removal device for the nuclear power plant includes: a steam generator 10, a steam outlet pipe section 100, a condensing heat exchange assembly 30, a condensate pipe section 200, an emergency makeup water tank 20, and a makeup water pipe section 300. Vertically, the condensing heat exchange assembly 30 and the emergency makeup water tank 20 are positioned above the steam generator 10. The inlets of the steam generator 10 and the condensing heat exchange assembly 30 are connected via the steam outlet pipe section 100, which is equipped with a first isolation valve 1. The outlet of the condensing heat exchange assembly 30 is connected to the steam generator 10 via the condensate pipe section 200. A second isolation valve 2 is provided; the top of the emergency water supply tank 20 is connected between the first isolation valve 1 and the inlet of the condensing heat exchange component 30, and the bottom of the emergency water supply tank 20 is provided with a water outlet 23, which is connected to the steam generator 10 through a water supply pipe section 300, and the water supply pipe section 300 is provided with a third isolation valve 3; wherein, when the passive residual heat removal device of the nuclear power plant is in the initial state, the first isolation valve 1 is configured to be normally open, the second isolation valve 2 is configured to be normally closed, and when the emergency water supply tank 20 is filled with water, the first liquid level of the water in the emergency water supply tank 20 is lower than the top surface of the emergency water supply tank 20.

[0044] It should be noted that, in addition to the aforementioned passive waste heat removal devices, the passive waste heat removal system of a nuclear power plant also includes the normal operating circuit of the steam generator. The normal operating circuit of the steam generator in the passive waste heat removal system refers to the pipelines and components installed on those pipelines during normal operation of the system. This normal operating circuit can also be referred to as a secondary circuit or is a secondary circuit. Figure 1 The two dashed lines connecting to the steam generator 10 schematically illustrate part of the pipeline structure connecting the normal operating circuit of the steam generator to the steam generator 10. This normal operating circuit of the steam generator is a complete circulation pipeline. Figure 1 As shown, the normal operating circuit of the steam generator includes an outflow pipe 400 and an inflow pipe 500. The outflow pipe 400 is equipped with a fourth isolation valve 5, and the inflow pipe 500 is equipped with a fifth isolation valve 6 and a main water supply check valve 7. The main water supply check valve 7 is located between the fifth isolation valve 6 and the steam generator 10. A water supply assembly (not shown in the figure) is also provided between the outflow pipe 400 and the inflow pipe 500.

[0045] The steam generator 10 in the passive residual heat removal system of the aforementioned nuclear power plant is typically located inside the containment, that is... Figure 1To the left of the double-dotted line, in the passive residual heat removal system of this nuclear power plant, the steam generator 10, level gauge 40, emergency makeup water check valve 4, and main makeup water check valve 7 are located inside the containment. The first isolation valve 1, second isolation valve 2, third isolation valve 3, fourth isolation valve 5, and fifth isolation valve 6 are all located outside the reactor containment. Figure 1 To the right of the double-dotted line. This not only facilitates the installation and maintenance of main circuits and isolation valves in the normal operation circuits of the passive residual heat removal device and steam generator in the nuclear power plant, but also improves the safety of manual maintenance.

[0046] Under normal operating conditions, the steam generator normal operation loop of the passive residual heat removal system of the nuclear power plant is maintained by controlling the fourth isolation valve 5, the fifth isolation valve 6, and the main makeup water check valve 7. At this time, the passive residual heat removal device is in standby mode, the emergency makeup water tank 20 is filled with water, and the first liquid level in the emergency makeup water tank 20 is lower than the top surface of the tank. This is because the first isolation valve 1 is normally open, thus preventing the emergency makeup water tank 20 from flowing into the steam generator 10 via the steam outlet pipe section 100. When the passive residual heat removal device and system malfunction, the second isolation valve 2 needs to be opened, and the passive residual heat removal device begins to operate. If necessary, that is, only when the liquid level in the steam generator 10 is low, the third isolation valve 3 is opened, and water from the emergency makeup water tank 20 replenishes the steam generator 10 through the makeup water pipe section 300 and the condensate pipe section 200.

[0047] It should be noted that the steam generator 10, steam outlet pipe section 100, first isolation valve 1 and condensing heat exchange component 30 constitute the steam discharge cooling front path, the condensing heat exchange component 30, condensate pipe section 200 and second isolation valve 2 constitute the steam discharge cooling rear path, and the steam discharge cooling front path and the steam discharge cooling rear path constitute the steam natural discharge circulation subsystem of steam generator 10. This application positions the condenser heat exchange assembly 30 and the emergency makeup water tank 20 vertically above the steam generator 10. The hot steam generated by the steam generator 10 rises and flows sequentially through the steam outlet pipe section 100 and the emergency makeup water tank 20 to the inlet of the condenser heat exchange assembly 30. After being cooled by the condenser heat exchange assembly 30, the hot steam condenses into water and, under its own gravity, returns to the steam generator 10 through the condensate pipe. The density difference between the rising steam before the steam discharge cooling path and the falling condensate after the steam discharge cooling path provides the driving force for natural circulation, thus achieving the smooth discharge of core heat from the steam generator 10 through natural circulation. Simultaneously, the emergency makeup water tank 20, the makeup water pipe section 300, and the third isolation valve 3 constitute the steam discharge makeup water subsystem. Figure 1As shown by the dashed line in the figure, in this embodiment, an outlet 23 can be provided on the bottom surface of the emergency water supply tank 20, or on the top side of the emergency water supply tank 20. Thus, when the liquid level in the steam generator 10 is low, the opening and closing of the third isolation valve 3 can be controlled to provide effective water supply to the steam generator 10 through the emergency water supply tank 20 and the water supply pipe section 300 when the water volume in the system is insufficient, ensuring the effective operation of the system and enabling the core heat in the steam generator 10 to be more effectively discharged, thereby improving the safety and reliability of the passive residual heat removal device of the nuclear power plant. Furthermore, if the first isolation valve 1 is set to normally closed, opening the first isolation valve 1 will cause high-temperature steam to be directly injected into the colder emergency water supply tank 20, which will cause equipment vibration due to steam annihilation and have a significant load impact on the equipment. This application connects the top of the emergency water supply tank 20 between the first isolation valve 1 and the inlet of the condensation heat exchange component 30, which can ensure that the emergency water supply tank 20 is in a hot standby state and avoid the adverse hydraulic load impact caused by steam being injected into the cold water of the emergency water supply tank 20 during system startup.

[0048] This application places the condensing heat exchanger 30 and the emergency water supply tank 20 above the steam generator 10. The condensing heat exchanger 30 provides a cold source. The inlet of the condensing heat exchanger 30 is connected to the steam generator 10 via a steam outlet pipe section 100. The top of the emergency water supply tank 20 is connected between the first isolation valve 1 on the steam outlet pipe section 100 and the inlet of the condensing heat exchanger 30. The first isolation valve 1 on the steam outlet pipe section 100 is set to normally open. The outlet of the condensing heat exchanger 32 is connected to the steam generator 10 via... The condensate pipe section 200 is connected, and the second isolation valve 2 on the condensate pipe section 200 is set to normally closed. Thus, even if the nuclear power plant experiences a complete loss of secondary feedwater in the event of a power outage, and the passive residual heat removal device is operating, the steam generated by the steam generator 10 rises through the steam outlet pipe section 100, passes the top of the emergency makeup water tank 20, and reaches the inlet of the condensing heat exchange assembly 30. After being cooled by the condensing heat exchange assembly 30, it becomes water and returns to the steam generator 10 through the condensate pipe section 200 under gravity. The system eliminates the need for active mechanical pumps such as electric or steam pumps, enabling passive natural circulation. This allows the core heat from the steam generator 10 to be smoothly discharged. This not only reduces reliance on power supply and HVAC systems, thus lowering the probability of system failure due to power outages, but also ensures the emergency water tank 20 is in hot standby mode, preventing adverse hydraulic loads caused by steam injection into the cold water during system startup. Furthermore, when the liquid level in the steam generator 10 is low, the opening of the third isolation valve 3 allows water from the emergency water tank 20 to flow out through the bottom outlet 23 under gravity, and then automatically replenish the steam generator 10 via the water supply pipe section 300. This ensures the smooth discharge of core heat from the steam generator 10. Thus, while maintaining safety, the system improves the reliability of the residual heat removal system during power outages, thereby enhancing the safety of the nuclear power plant. Additionally, the system is simple in structure, easy to arrange, highly controllable, and provides high cooling performance.

[0049] It should be noted that, under normal circumstances, the steam generator 10 is separated from other components by a containment structure. Figure 1 Separated by vertical double-dotted lines, the aforementioned condensing heat exchange component 30, emergency water supply tank 20, first isolation valve 1, second isolation valve 2, and third isolation valve 3 are all located in a safe building outside the containment structure to ensure the personal safety of installation and maintenance personnel. Regarding the first isolation valve 1, second isolation valve 2, and third isolation valve 3, in Figure 1, hollow isolation valves represent normally open isolation valves, and solid isolation valves represent normally closed isolation valves.

[0050] exist Figure 1In the diagram, the two dashed lines connecting to the steam generator 10 represent the circuitry of the nuclear reactor under normal operating conditions. Figure 1 The diagram only schematically shows part of the wiring connected to the steam generator 10.

[0051] like Figure 2 and Figure 3 As shown, in this embodiment, a second isolation valve 2 is provided between the connection point of the water supply pipe section 300 and the condensate pipe section 200 and the steam generator 10.

[0052] Compared to directly connecting the water supply line to the steam generator 10, the above configuration ensures that water can only be supplied to the steam generator 10 when the second isolation valve 2 is open. In other words, during normal operation of the steam generator 10's natural steam discharge circulation subsystem, which consists of the steam discharge cooling front path and the steam discharge cooling rear path, the third isolation valve 3 can be controlled to supply water to the steam generator 10. This prevents the passive emergency water supply tank 20 from accidentally starting and directly injecting water into the steam generator 10 during normal unit operation, thus reducing the impact of accidental opening of the emergency water supply tank 20 on the normal operation of the unit.

[0053] The first isolation valve 1 mentioned above can be an electric isolation valve or a manual isolation valve.

[0054] In some embodiments, the second isolation valve 2 is an electrically operated isolation valve, and the third isolation valve 3 is an electrically operated isolation valve; the passive residual heat removal device of the nuclear power plant also includes a residual heat removal controller (not shown in the figure), which is electrically connected to the second isolation valve 2 and to the third isolation valve 3.

[0055] The above settings improve the automation level of the passive waste heat removal device in nuclear power plants and reduce the risk of human radiation caused by manual activation.

[0056] It should be noted that when the first isolation valve 1 is an electric isolation valve, the first isolation valve 1 may be electrically connected to the waste heat discharge controller, but is not limited to that connection.

[0057] like Figure 2 As shown, in this embodiment, the second isolation valve 2 includes two isolation valves connected in parallel on the condensate pipe section 200.

[0058] By installing two isolation valves in parallel on the condensate pipe section 200, the passive waste heat removal device of the nuclear power plant can still operate normally even if one of the isolation valves fails, thus improving the reliability of the passive waste heat removal device.

[0059] Of course, one or three other isolation valves can also be installed in the condensate pipe section 200, and no specific limitation is made here.

[0060] The structure of the third isolation valve 3 may be, but is not limited to, the same as that of the second isolation valve 2.

[0061] like Figure 2 As shown, in this embodiment, the third isolation valve 3 includes two isolation valves, and the two isolation valves are arranged side by side in two water supply pipe sections 300.

[0062] In this way, even if one isolation valve fails, water can still be supplied to the steam generator 10 by controlling the other isolation valve, thereby further improving the reliability of the normal operation of the passive waste heat removal device of the nuclear power plant.

[0063] Of course, one, three, four, or other numbers of isolation valves can also be installed in the water supply pipe section 300. When three isolation valves are installed in the water supply pipe section 300, all three isolation valves can be connected in parallel to the water supply pipe section 300, or two of the isolation valves can be connected in parallel to the water supply pipe section 300, and the other isolation valve can be set before or after the two parallel isolation valves. When four isolation valves are installed in the water supply pipe section 300, the four isolation valves can be connected in parallel first and then in series, or the two isolation valves can be connected in series first, and then the two components with two isolation valves connected in series can be connected in parallel to the water supply pipe section 300. No specific limitation is made here.

[0064] like Figure 2 As shown, in this embodiment, the condensate pipe section 200 is equipped with an emergency water supply check valve 4, which is located between the second isolation valve 2 and the steam generator 10. This prevents water in the steam generator 10 from flowing back in the pipe, thereby protecting the equipment and avoiding accidents or efficiency losses caused by backflow.

[0065] like Figure 2 As shown, in this embodiment, the passive residual heat removal device for nuclear power plants also includes a level gauge 40 and a water replenishment controller (not shown in the figure). The level gauge 40 is installed on the steam generator 10 and is used to measure the liquid level in the steam generator 10. The water replenishment controller is electrically connected between the level gauge 40 and the third isolation valve 3. The water replenishment controller is configured to: open the third isolation valve 3 when the liquid level in the steam generator 10 is lower than a preset value; and close the third isolation valve 3 when the liquid level in the steam generator 10 is equal to or greater than the preset value.

[0066] The function of the aforementioned level gauge 40 is to measure the liquid level parameter inside the steam generator 10. The level gauge 40 can be installed independently on the steam generator 10. When the steam generator 10 integrates the level gauge 40 or has electronic devices that measure the liquid level parameter inside the steam generator 10, it is not necessary to install a separate level gauge 40, as long as the measured liquid level parameter inside the steam generator 10 can be sent to the water replenishment controller.

[0067] The function of the aforementioned water replenishment controller is to obtain the liquid level parameters inside the steam generator 10. This water replenishment controller may, but is not limited to, be the same controller as the waste heat discharge controller.

[0068] Through the above settings, the passive waste heat removal device of the nuclear power plant can automatically replenish water to the steam generator 10.

[0069] The structure of the condenser heat exchanger 30 is described in detail below.

[0070] like Figure 4 As shown, in this embodiment, the condensing heat exchange assembly 30 includes a condensate tank 31 and a condensing heat exchanger 32. The condensing heat exchanger 32 is disposed in the condensate tank 31, and the inlet of the condensing heat exchanger 32 is located below the outlet of the condensing heat exchanger 32. The inlet and outlet of the condensing heat exchange assembly 30 are the inlet and outlet of the condensing heat exchanger 32, respectively. The condensing heat exchanger 32 is disposed at the bottom of the condensate tank 31. In the vertical direction, the inlet of the condensing heat exchanger 32 is located on the top surface of the condensing heat exchanger 32, and the outlet of the condensing heat exchanger 32 is located on the bottom surface of the condensing heat exchanger 32.

[0071] In the vertical direction, the inlet and outlet of the condenser heat exchanger 32 may, but are not limited to, be located on the top and bottom surfaces of the condenser heat exchanger 32, respectively.

[0072] With the above setup, when the top of the emergency makeup water tank 20 is connected to the inlet of the condensing heat exchanger 32, and the passive waste heat removal device of the nuclear power plant is operating normally, the emergency makeup water tank 20 and the condensing heat exchanger 32 form a communicating vessel. That is to say, the first liquid level of the emergency makeup water tank 20 will eventually be flush with the liquid level inside the condensing heat exchanger 32.

[0073] When setting the position of the condenser heat exchanger 32, since the water in the emergency water tank 20 will be in communication with the water inside the condenser heat exchanger 32, the bottom surface of the emergency water tank 20 needs to be raised accordingly. Specifically, after multiple tests, it was found that the bottom surface of the emergency water tank 20 should not be lower than the center line of the condenser heat exchanger 32 in the horizontal direction. Figure 4 (The dotted line on the condenser heat exchanger 32). That is to say, assuming the bottom of the emergency water tank is 50m high or at an elevation of 50m, the vertical centerline of the condenser heat exchanger 32 can be at a height of 50m, or greater or less than 50m. This ensures that all the water in the emergency makeup water tank 20 can be injected into the steam generator after an accident.

[0074] It should be noted that the elevation of the bottom of the emergency water supply tank 20 can be, but is not limited to, 50m. The 50m here is just an example, and the specific height will be determined according to the actual situation. No specific limit is set here.

[0075] like Figure 3 As shown, in this embodiment, the condensate tank 31 includes an upper cavity 301 and a lower cavity 302 that are connected in the vertical direction. The condenser heat exchanger 32 is disposed in the lower cavity 302. The volume of the lower cavity 302 is larger than the volume of the condenser heat exchanger 32, and the volume of the lower cavity 302 is smaller than the volume of the upper cavity 301.

[0076] This not only allows the lower cavity 302 to accommodate the condenser heat exchanger 32, but also lowers the center of gravity of the condenser heat exchange assembly 30 by placing the condenser heat exchanger 32 in the lower cavity 302, thereby improving the stability of the condenser heat exchange assembly 30.

[0077] In some embodiments, the area of ​​the lower cavity 302 on the first plane is smaller than the area of ​​the upper cavity 301 on the first plane, and the first plane is a plane perpendicular to the vertical direction. It should be noted that the area of ​​the lower cavity 302 on the first plane is designed according to the space occupied by the condensing heat exchanger 32, ensuring that the lower cavity 302 can accommodate the condensing heat exchanger 32. In this way, the inner wall of the lower cavity 302 can restrict and fix the condensing heat exchanger 32, thereby further improving the stability of the condensing heat exchange assembly 30.

[0078] The structure of the emergency water supply tank 20 will be described in detail below.

[0079] like Figure 4 As shown, in this embodiment, the bottom surface of the emergency water supply tank 20 is provided with a water outlet 23, and the top of the emergency water supply tank 20 is provided with a first opening 21 and a second opening 22. The first opening 21 is connected to the steam outflow pipe section 100, and the second opening 22 is connected to the inlet of the condensing heat exchanger 32. In the vertical direction, the first liquid level in the emergency water supply tank 20 is configured to be lower than the first opening 21 and lower than the second opening 22.

[0080] The above settings prevent water from the emergency water supply tank 20 from entering the steam outlet pipe section 100.

[0081] It should be noted that in some embodiments, the second opening 22 and the first opening 21 are located on the same horizontal plane in the vertical direction, such as... Figure 4 As shown. Alternatively, in some other embodiments, the second opening 22 is higher than the first opening 21, as shown. Figure 5 As shown. Users can choose according to their needs; no specific restrictions are imposed here.

[0082] like Figure 4 As shown, in this embodiment, in the vertical direction, the second opening 22 of the emergency water supply tank 20 is higher than the inlet of the condensation heat exchange component 30.

[0083] In this way, the steam passing through the top of the emergency water supply tank 20 will condense and enter the inlet of the condensing heat exchanger 32 under the action of gravity.

[0084] It should be noted that the relative positions of the bottom surface of the emergency water supply tank 20 and the center line of the condensing heat exchanger 32 in the vertical direction should refer to the above-mentioned content about the condensing heat exchanger 32, and will not be repeated here.

[0085] In some embodiments, the passive residual heat removal device for nuclear power plants further includes a dosing assembly (not shown) connected to the condensate tank 31.

[0086] In this way, the water in the condensate tank 31 can be treated using the dosing assembly.

[0087] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A passive waste heat removal device for a nuclear power plant, characterized in that, include: The steam generator (10), steam outlet pipe section (100), condensing heat exchange assembly (30), condensate pipe section (200), emergency water supply tank (20) and water supply pipe section (300) are arranged vertically above the steam generator (10); The inlet of the steam generator (10) and the condensing heat exchange assembly (30) are connected through the steam outlet pipe section (100), which is equipped with a first isolation valve (1); the outlet of the condensing heat exchange assembly (30) is connected to the steam generator (10) through the condensate pipe section (200), which is equipped with a second isolation valve (2); the top of the emergency water supply tank (20) is connected between the first isolation valve (1) and the inlet of the condensing heat exchange assembly (30), and the bottom of the emergency water supply tank (20) is equipped with a water outlet (23), which is connected to the steam generator (10) through the water supply pipe section (300), which is equipped with a third isolation valve (3); When the passive residual heat removal device of the nuclear power plant is in its initial state, the first isolation valve (1) is configured to be normally open, the second isolation valve (2) is configured to be normally closed, and when the emergency water supply tank (20) is filled with water, the first liquid level of the water in the emergency water supply tank (20) is lower than the top surface of the emergency water supply tank (20).

2. The passive waste heat removal device for nuclear power plants according to claim 1, characterized in that, The second isolation valve (2) is provided between the connection point of the water supply pipe section (300) and the condensate pipe section (200) and the steam generator (10).

3. The passive waste heat removal device for nuclear power plants according to claim 1, characterized in that, The emergency water supply tank (20) has the water outlet (23) on its bottom surface.

4. The passive waste heat removal device for nuclear power plants according to claim 3, characterized in that, The top of the emergency water supply tank (20) is provided with a first opening (21) and a second opening (22). The first opening (21) is connected to the steam outlet pipe section (100), and the second opening (22) is connected to the inlet of the condenser heat exchanger (32). In the vertical direction, the first liquid level in the emergency water replenishment tank (20) is configured to be lower than the first opening (21) and the first liquid level is lower than the second opening (22).

5. The passive waste heat removal device for nuclear power plants according to claim 4, characterized in that, In the vertical direction, the second opening (22) is located on the same horizontal plane as the first opening (21), or the second opening (22) is higher than the first opening (21).

6. The passive waste heat removal device for nuclear power plants according to claim 5, characterized in that, In the vertical direction, the second opening (22) of the emergency water supply tank (20) is higher than the inlet of the condensation heat exchange assembly (30); And / or, the condensing heat exchange assembly (30) includes a condensate tank (31) and a condensing heat exchanger (32), the condensing heat exchanger (32) being disposed in the condensate tank (31), and the bottom surface of the emergency water supply tank (20) being not lower than the center line of the condensing heat exchanger (32) in the horizontal direction.

7. The passive residual heat removal device for nuclear power plants according to any one of claims 1 to 6, characterized in that, The condensing heat exchange assembly (30) includes a condensate tank (31) and a condensing heat exchanger (32). The condensing heat exchanger (32) is disposed in the condensate tank (31). The inlet of the condensing heat exchanger (32) is located below the outlet of the condensing heat exchanger (32). The inlet and outlet of the condensing heat exchange assembly (30) are the inlet and outlet of the condensing heat exchanger (32), respectively. The condenser heat exchanger (32) is located at the bottom of the condensate tank (31). In the vertical direction, the inlet of the condenser heat exchanger (32) is located on the top surface of the condenser heat exchanger (32), and the outlet of the condenser heat exchanger (32) is located on the bottom surface of the condenser heat exchanger (32).

8. The passive waste heat removal device for nuclear power plants according to claim 7, characterized in that, The condensate tank (31) includes an upper cavity (301) and a lower cavity (302) that are connected in the vertical direction. The condensing heat exchanger (32) is disposed in the lower cavity (302). The volume of the lower cavity (302) is larger than the volume of the condensing heat exchanger (32), and the volume of the lower cavity (302) is smaller than the volume of the upper cavity (301).

9. The passive waste heat removal device for nuclear power plants according to claim 8, characterized in that, The area of ​​the lower cavity (302) on the first plane is smaller than the area of ​​the upper cavity (301) on the first plane, and the first plane is a plane perpendicular to the vertical direction.

10. The passive residual heat removal device for nuclear power plants according to any one of claims 1 to 6, 8 to 9, characterized in that, The number of the second isolation valve (2) is one or more.

11. The passive waste heat removal device for nuclear power plants according to claim 10, characterized in that, The second isolation valve (2) includes two isolation valves connected in parallel to the condensate pipe section (200).

12. The passive residual heat removal device for nuclear power plants according to any one of claims 1 to 6, 8 to 9, characterized in that, The number of the third isolation valve (3) is one or more.

13. The passive waste heat removal device for nuclear power plants according to claim 12, characterized in that, The third isolation valve (3) includes two isolation valves connected in parallel to the water supply pipe section (300).

14. The passive residual heat removal device for nuclear power plants according to any one of claims 1 to 6, 8 to 9, characterized in that, The passive residual heat removal device for the nuclear power plant also includes a level gauge (40) and a water replenishment controller. The level gauge (40) is installed on the steam generator (10) and is used to measure the liquid level in the steam generator (10). The water replenishment controller is electrically connected between the level gauge (40) and the third isolation valve (3). The water replenishment controller is configured to: open the third isolation valve (3) when the liquid level in the steam generator (10) is lower than a preset value; and close the third isolation valve (3) when the liquid level in the steam generator (10) is equal to or greater than the preset value.

15. The passive residual heat removal device for nuclear power plants according to any one of claims 1 to 6, 8 to 9, characterized in that, The second isolation valve (2) is an electric isolation valve, and the third isolation valve (3) is an electric isolation valve; The passive waste heat removal device for the nuclear power plant also includes a waste heat removal controller, which is electrically connected to the second isolation valve (2) and the third isolation valve (3).

16. The passive residual heat removal device for nuclear power plants according to any one of claims 1 to 6, 8 to 9, characterized in that, The condensate pipe section (200) is equipped with an emergency water supply check valve (4), which is located between the second isolation valve (2) and the steam generator (10).

17. A passive waste heat removal system, characterized in that, The passive residual heat removal device for nuclear power plants, as described in any one of claims 1 to 16, is further connected to a normal operating circuit for a steam generator. The normal operating circuit for a steam generator includes an outflow pipe (400) and an inflow pipe (500). The outflow pipe (400) is provided with a fourth isolation valve (5). The inflow pipe (500) is provided with a fifth isolation valve (6) and a main water supply check valve (7). The main water supply check valve (7) is located between the fifth isolation valve (6) and the steam generator (10). A water supply assembly is also provided between the outflow pipe (400) and the inflow pipe (500).

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