Passive containment spray system

Abstract

The invention discloses a passive containment spraying system which comprises a gas storage tank, a pneumatic isolating valve, a pressure reduction pore plate, an out-shell isolating valve and a control module, wherein the gas storage tank, the pneumatic isolating valve, the pressure reduction pore plate and the out-shell isolating valve are arranged outside a containment and connected through a pipeline, and the control module is communicated with the pneumatic isolating valve and the out-shell isolating valve; the water storage tank is communicated with the depressurization pore plate, a cooling medium can be accommodated in the water storage tank, and the water storage tank is communicated with the spray header through an isolating valve outside the containment; expandable gas can be contained in the gas storage tank, reaches the water storage tank after passing through the pneumatic isolation valve and the pressure reduction pore plate, and drives a cooling medium to flow through the spraying header. The passive containment spraying system provided by the embodiment of the invention does not depend on a power device, drives the system to operate in a pressure accumulation mode, and is suitable for removing radioactivity in the containment after an accident, so that the radioactivity released to the environment is reduced, and the safety and reliability of a nuclear power plant are improved.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear power, and in particular to a passive containment spray system. Background Art

[0002] With the continuous development of society, the demand for electric energy is getting higher and higher. Nuclear power, as an efficient and clean form of energy, has gradually become an important choice to meet energy demand. However, the safety of nuclear power plants has always been the focus of public and industry attention. The containment of a nuclear power plant is the last barrier to prevent the leakage of radioactive materials. Its design and construction quality are directly related to the safe operation of the nuclear power plant. The third-generation nuclear power technology has made many improvements in the design of the containment, and adopted a double-layer containment structure to improve its accident resistance and protection performance. The double-layer containment usually consists of an inner shell and an outer shell. The main function of the inner shell is to bear pressure, and the main function of the outer shell is to prevent external impact. Through the multi-level protection design, the double-layer containment significantly improves the safety and reliability of nuclear power plants, ensuring that radioactive materials can be effectively contained in the event of an accident to prevent them from leaking into the environment. In addition, the design of the containment spray system of a nuclear power plant adopts an active design. In the case of active spraying under the design basis accident, the radioactivity of the atmosphere in the shell can be effectively reduced. However, after a nuclear power plant power outage, failure of the active containment spray system or other related accidents, the active containment spray system will fail. If the heat in the containment cannot be discharged in time, the containment may fail due to over-temperature and over-pressure, causing radioactivity to be released into the environment.

[0003] Patent CN104021822 discloses a passive containment spray and heat dissipation system, the structure of which includes several pressurized water tanks arranged outside the containment, the outlet pipes of the pressurized water tanks are connected to the header, the header is connected to the spray ring pipe in the containment through the containment penetration, an electric isolation valve is provided on the header outside the containment, and a check valve is provided on the header inside the containment, which can provide spray flow into the containment in the event of a serious accident to reduce the temperature and pressure of the containment. Patent CN103985422 discloses an active and passive nuclear steam supply system based on 177 core and a nuclear power plant thereof, including: an active and passive heat removal system, the active and passive heat removal system includes an active system and a passive system, the active system includes a safety spray system, the safety spray system includes a third water source, an annular spray pipe arranged at the top of the containment, a spray pipeline connected to the third water source at one end and the annular spray pipe at the other end, and also includes a third pump and a first heat exchanger arranged in series on the spray pipeline, and the core residual heat is removed by combining active and passive methods to improve the safety and reliability of the nuclear power plant. However, the above system cannot reduce the radioactivity in the containment as a whole in a short time after the accident. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned technical problems.

[0005] To this end, the first purpose of the present invention is to propose a passive containment spray system that does not rely on a power device and is suitable for removing radioactivity from the containment after an accident, thereby reducing radioactivity released into the environment and improving the safety and reliability of nuclear power plants.

[0006] To achieve the above object, the present invention provides a passive containment spray system in a first aspect, the spray system comprising:

[0007] Gas storage tanks, pneumatic isolation valves, pressure-reducing orifice plates, and outer-shell isolation valves are installed outside the containment and connected by pipelines.

[0008] A control module, the control module is in communication with the pneumatic isolation valve and the outer shell isolation valve;

[0009] A water storage tank and a spray header arranged in the containment, the water storage tank is connected to the pressure-reducing orifice plate, the water storage tank can contain cooling medium, and the water storage tank is connected to the spray header through an external isolation valve;

[0010] The gas storage tank can contain expandable gas, which reaches the water storage tank after passing through the pneumatic isolation valve and the pressure reduction orifice plate. The expandable gas drives the cooling medium to flow through the spray header.

[0011] Furthermore, the spray manifold includes a first spray ring pipe and a second spray ring pipe, and the first spray ring pipe and the second spray ring pipe are arranged in sequence in a direction perpendicular to the ground. The first spray ring pipe is arranged above the second spray ring pipe, one side of the first spray ring pipe is connected to one side of the second spray ring pipe through a pipeline, and the other side of the first spray ring pipe is connected to the other side of the second spray ring pipe through a pipeline, and the pipeline passing through the containment penetration piece is respectively connected to both sides of the first spray ring pipe and both sides of the second spray ring pipe.

[0012] Furthermore, the radius of the first spray ring pipe is 4-6m, and the radius of the second spray ring pipe is 14-15m.

[0013] Furthermore, the number of nozzles arranged on the spray manifold is greater than or equal to 168, the number of first nozzles on the first spray ring pipe is greater than or equal to 68, and the number of second nozzles on the second spray ring pipe is greater than or equal to 100.

[0014] Furthermore, the first nozzles are evenly distributed on the first spray ring pipe, which includes a first nozzle group, a second nozzle group and a third nozzle group. The number of first nozzles in the first nozzle group, the number of first nozzles in the second nozzle group and the number of first nozzles in the third nozzle group satisfy 2:6:9.

[0015] Furthermore, the arrangement angle of the first nozzle located first in the first nozzle group along the clockwise / counterclockwise direction is 0°, the arrangement angle of the first nozzle located first in the second nozzle group along the same direction is 7.5°, and the arrangement angle of the first nozzle located first in the third nozzle group along the same direction is 0°.

[0016] Furthermore, in the first spray ring pipe, excluding the first nozzle in the first nozzle group, the first nozzle in the second nozzle group, and the first nozzle in the third nozzle group, the arrangement angles of the remaining first nozzles are a combination of any 3-6 arrangement angles of the preset 26 arrangement angles, and the number of nozzles corresponding to each arrangement angle is less than or equal to M / m, wherein M represents the number of the remaining first nozzles, and m represents the first type number of the selected arrangement angles.

[0017] Furthermore, the second nozzles are evenly distributed on the second spray ring pipe, the second spray ring pipe includes a fourth nozzle group and a fifth nozzle group, and the number of second nozzles in the fourth nozzle group and the number of second nozzles in the fifth nozzle group satisfy 9:16.

[0018] Further, the arrangement angle of the second nozzle located first in the clockwise / counterclockwise direction in the fourth nozzle group is 0°, and the arrangement angle of the second nozzle located first in the fifth nozzle group along the same direction is 10°.

[0019] Furthermore, in the second spray ring pipe, excluding the first nozzle in the fourth nozzle group and the first nozzle in the fifth nozzle group, the arrangement angles of the remaining second nozzles are a combination of any 3-6 arrangement angles of the preset 26 arrangement angles, and the number of nozzles corresponding to each arrangement angle is less than or equal to N / n, wherein N represents the number of the remaining second nozzles, and n represents the second type number of the selected arrangement angles.

[0020] Furthermore, the diameter direction of the first spray ring pipe or the second spray ring pipe where the nozzle is located is taken as the horizontal direction, the horizontal direction pointing to the center of the first spray ring pipe or the center of the second spray ring pipe is taken as the first horizontal direction, the horizontal direction pointing in the opposite direction of the center of the first spray ring pipe or the center of the second spray ring pipe is taken as the second horizontal direction, and the direction perpendicular to the ground is taken as the vertical direction. The preset 26 arrangement angles include the angle type between the first horizontal direction and the vertical direction, and the angle type between the second horizontal direction and the vertical direction, and the angle types include 0°, 7.5°, 15°, 30°, 40°, 45°50°, 60°, 70°, 75°, 80°, 90°, and 120°.

[0021] Furthermore, the nozzle is an open nozzle, the spray flow rate of the nozzle is less than or equal to 2kg / h, and the spray angle of the nozzle is less than or equal to 65°.

[0022] Furthermore, the pressure reducing orifice plate is a single-stage orifice plate, and the inner aperture size of the pressure reducing orifice plate is 60-80 mm.

[0023] Furthermore, the spray system also includes a heat exchange water tank arranged in the containment shell, and alkaline water is stored in the heat exchange water tank.

[0024] Furthermore, the gas storage tank is cylindrical, the top of the gas storage tank is semi-ellipsoidal, and an outlet pipeline is arranged on the top of the gas storage tank.

[0025] Furthermore, the expandable gas is nitrogen, and the volume of nitrogen in the gas tank is 5-15m 3 , the pressure of nitrogen in the gas storage tank is not less than 4-15MPa.

[0026] Furthermore, the spray system also includes a check valve arranged in the containment shell, and there are at least two external isolation valves 5, and at least two external isolation valves are arranged in parallel. The check valve and at least two external isolation valves constitute a containment shell isolation valve group.

[0027] Furthermore, the spray system also includes an active spray interface, which is arranged in the containment shell and is connected to a pipeline between the check valve and the containment shell penetration piece.

[0028] Furthermore, the cooling medium is deionized water, and the volume of the water storage tank is 100-200m 3 , the design pressure in the water storage tank is lower than 8MPa.

[0029] By applying the above technical solution of the present invention, at least the following technical effects are achieved:

[0030] 1. The passive containment spray system does not rely on a power device, but relies on a pressure storage method to drive the system to operate. It is suitable for removing radioactivity from the containment after an accident, thereby reducing the radioactivity released into the environment and improving the safety and reliability of the nuclear power plant.

[0031] 2. The passive containment spray system separates the gas storage tank and the water storage tank through a split design, which can significantly reduce the volume and pressure of the water storage tank. It is also equipped with a pressure reducing orifice plate, which can balance the flow of the passive containment spray system and extend the spray time to meet the preset spray time requirements.

[0032] 3. The passive containment spray system is provided with a heat exchange water tank, which can retain the radioactive substances in the liquid sprayed into the containment in the heat exchange water tank, thereby reducing the radioactive substances in the atmosphere of the containment, thereby reducing the dose released into the environment and improving the safety of the nuclear power plant.

[0033] 4. The passive containment spray system is provided with a spray header, which includes a first spray ring pipe and a second spray ring pipe. By arranging a first nozzle on the first spray ring pipe and a second nozzle on the second spray ring pipe, it is ensured that the cooling medium sprayed from the spray header can fully cover the containment, effectively reducing the radioactivity of the atmosphere in the containment after the accident.

[0034] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0036] Figure 1 A schematic structural diagram of a passive containment spray system according to an embodiment is shown;

[0037] Figure 2 A schematic diagram of the arrangement angle of the nozzle according to an embodiment is shown.

[0038] Figure numerals: 1. containment; 2. gas storage tank; 3. pneumatic isolation valve; 4. pressure reducing orifice; 5. outer shell isolation valve; 6. control module; 7. water storage tank; 8. spray header; 81. first spray ring pipe; 82. second spray ring pipe; 9. containment penetration; 10. heat exchange water tank; 11. check valve; 12. active spray interface. DETAILED DESCRIPTION

[0039] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] The present invention is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed by the present invention.

[0041] In the description, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0042] According to a first aspect of the present invention, a passive containment spray system is provided.

[0043] When an accident occurs in a nuclear power plant, the pressure and temperature inside the containment shell increase. For a LOCA accident (loss of coolant accident), the radioactivity inside the shell will also increase. As the pressure inside the containment shell increases, the gas inside the shell may leak into the environment. In order to limit the radiation dose outside the shell, it is necessary to reduce the radioactivity of the atmosphere inside the shell. The passive containment shell spray system in this embodiment does not rely on a power device, but relies on a pressure storage method to drive the system to operate. After an accident, the atmosphere inside the containment shell is sprayed to reduce the radioactivity inside the shell, thereby reducing the radioactivity released to the environment.

[0044] like Figure 1 As shown, in this embodiment, the passive containment spray system includes: a gas storage tank 2, a pneumatic isolation valve 3, a pressure reducing orifice plate 4, and an external containment isolation valve 5, which are arranged outside the containment 1 and connected through pipelines.

[0045] In this embodiment, if Figure 1 As shown, the passive containment spray system also includes a control module 6. Specifically, the control module 6 is connected to the pneumatic isolation valve 3 and the outer shell isolation valve 5, and is used to send a start signal after an accident occurs to control the pneumatic isolation valve 3 and the outer shell isolation valve 5 to open, so as to connect the gas storage tank 2, the pneumatic isolation valve 3, the pressure reduction orifice 4, and the outer shell isolation valve 5. It should be noted that the pneumatic isolation valve 3 isolates the gas storage tank 2 and the water storage tank 7, so that the water storage tank 7 is not pressurized before the control module 6 sends a start signal, so that the water storage tank 7 contains sufficient cooling medium, avoiding the volume occupation of the water storage tank 7 caused by pressure, thereby effectively reducing the volume of the water storage tank 7, saving the time cost and labor cost of building a passive containment spray system.

[0046] In this embodiment, if Figure 1 As shown, the passive containment spray system also includes a water tank 7 and a spray header 8 arranged in the containment 1. Specifically, the water tank 7 is connected to the pressure reducing orifice 4, and the water tank 7 can contain cooling medium. The water tank 7 is connected to the spray header 8 through the outer shell isolation valve 5. It should be noted that the volume and pressure of the water tank 7 can be significantly reduced by separating the gas tank 2 and the water tank 7 through a split design. In addition, by combining the pressure reducing orifice 4, not only can the pressure behind the pressure reducing orifice 4 be reduced when the passive containment spray system is running, but the flow rate of the cooling medium can also be controlled, so that the flow rate of the cooling medium is more uniform and stable, and the utilization rate of the cooling medium is effectively improved.

[0047] In addition, the gas storage tank 2 can contain expandable gas, and the expandable gas reaches the water storage tank 7 after passing through the pneumatic isolation valve 3 and the pressure reduction orifice plate 4. The expandable gas drives the cooling medium to flow through the spray header 8.

[0048] Therefore, after an accident occurs, the control module 6 controls the pneumatic isolation valve 3 and the outer shell isolation valve 5 to open, connecting the passive containment spray system, and the gas in the gas storage tank 2 expands and passes through the pneumatic isolation valve 3 and the pressure-reducing orifice plate 4 to quickly reach the water storage tank 7. Under the pressure of the expandable gas, the cooling medium in the water storage tank 7 passes through the outer shell isolation valve 5 and enters the containment through the pipeline, and is finally sprayed out from the spray header 8. As the gas in the gas storage tank 2 expands, the pressure gradually decreases. At this time, the cooling medium in the water storage tank 7 is gradually squeezed out by the pressurized expandable gas and sprayed, so that the cooling medium in the water storage tank 7 is continuously injected into the reactor to reduce the radioactivity of the atmosphere in the shell, thereby improving the safety and reliability of the nuclear power plant.

[0049] Among them, the pressure-reducing orifice plate plays a role in balancing the flow of the passive containment spray system, and can extend the spray time. In the initial operation of the passive containment spray system, when the pressure in the gas tank 2 is high, the pressure drop of the expandable gas through the pressure-reducing orifice plate 4 is large, and the pressure of the driving water tank 7 is reduced, which reduces the initial flow of the passive containment spray system and avoids the cooling medium in the water tank 7 being emptied in advance and unable to meet the preset spray time requirements. Further, the pressure-reducing orifice plate 4 is set as a single-stage orifice plate, and by adjusting the inner aperture size of the pressure-reducing orifice plate, the pressure-reducing orifice plate 4 cooperates with the water volume of the cooling medium in the water tank 7 to meet the preset spray time requirements. In this embodiment, under the condition of ensuring the operation requirement of the passive containment spray system for 20 minutes, the inner aperture size of the pressure-reducing orifice plate 4 can be set to 60-80mm, preferably 68mm. In addition, the material of the pressure reducing orifice plate 4 can be set to stainless steel, which can be used for a long time in the working environment of a nuclear power plant without being corroded, and can withstand the impact load generated when high-temperature and high-pressure gas passes through the orifice plate, thereby ensuring the integrity of the orifice plate structure.

[0050] Furthermore, if Figure 1 As shown, the passive containment spray system further includes a heat exchange water tank 10 disposed in the containment 1. The heat exchange water tank 10 stores alkaline water, which is used to retain radioactive substances in the liquid sprayed into the containment 1 in the heat exchange water tank 10, thereby reducing radioactive substances in the atmosphere of the containment, thereby reducing the dose released into the environment, and improving the safety of the nuclear power plant.

[0051] Furthermore, if Figure 1 As shown, the spray system further includes a check valve 11 disposed in the containment 1. In addition, there are at least two external isolation valves 5 and at least two external isolation valves 5 are disposed in parallel, and the check valve 11 and at least two external isolation valves 5 form a containment isolation valve group. Based on the design of the isolation valve group, the passive containment spray system can meet the single accident criterion of the design basis accident commissioning.

[0052] Furthermore, if Figure 1 As shown, the spray header 8 includes a first spray ring pipe 81 and a second spray ring pipe 82. Specifically, the first spray ring pipe 81 and the second spray ring pipe 82 are sequentially arranged in a direction perpendicular to the ground, the first spray ring pipe 81 is arranged above the second spray ring pipe 82, one side of the first spray ring pipe 81 is connected to one side of the second spray ring pipe 82 through a pipeline, the other side of the first spray ring pipe 81 is connected to the other side of the second spray ring pipe 82 through a pipeline, and the pipeline passing through the containment penetration 9 is respectively connected to both sides of the first spray ring pipe 81 and both sides of the second spray ring pipe 82, so that the cooling medium in the water storage tank 7 is evenly circulated in the above-mentioned first spray ring pipe 81 and the second spray ring pipe 82.

[0053] In a specific embodiment, the radii of the first spray ring pipe 81 and the second spray ring pipe 82 are matched with the cross-section of the containment shell 1, and the radius of the first spray ring pipe 81 is set to 4-6m, and the radius of the second spray ring pipe 82 is set to 14-15m, so that the cooling medium sprayed from the spray manifold is evenly distributed inside the containment shell, thereby improving the efficiency of spray cooling and radioactive elimination.

[0054] Furthermore, the number of nozzles arranged on the spray manifold 8 is greater than or equal to 168, the number of first nozzles on the first spray ring pipe 81 is greater than or equal to 68, and the number of second nozzles on the second spray ring pipe 82 is greater than or equal to 100.

[0055] The nozzle is an open nozzle. Under the rated pressure drop, the nozzle's spray flow rate is less than or equal to 2kg / h, and the nozzle's spray angle is less than or equal to 65°. The small-flow open nozzle has a smaller spray angle and a narrower spray range, which can make the spray more uniform and concentrated, thereby meeting the spray coverage area requirements and improving the efficiency of reducing radioactivity in the shell.

[0056] Specifically, in one embodiment of the present invention, the first nozzles are evenly distributed on the first spray ring pipe 81, and the first spray ring pipe 81 includes a first nozzle group, a second nozzle group and a third nozzle group, and the number of first nozzles in the first nozzle group, the number of first nozzles in the second nozzle group and the number of first nozzles in the third nozzle group satisfy 2:6:9. For example, the number of first nozzles on the first spray ring pipe 81 is 68. Among them, the number of first nozzles in the first nozzle group is 8, the number of first nozzles in the second nozzle group is 24, and the number of first nozzles in the third nozzle group is 36.

[0057] Further, the arrangement angle of the first nozzle located in the first nozzle group in the clockwise / counterclockwise direction is 0°, the arrangement angle of the first nozzle located in the first direction in the second nozzle group is 7.5°, and the arrangement angle of the first nozzle located in the first direction in the third nozzle group is 0°. For example, the arrangement angle of the first nozzle located in the first direction in the first nozzle group is 0°, the arrangement angle of the first nozzle located in the first direction in the second nozzle group is 7.5°, and the arrangement angle of the first nozzle located in the first direction in the third nozzle group is 0°.

[0058] Furthermore, in the first spray ring pipe 81, excluding the first nozzle in the first nozzle group, the first nozzle in the second nozzle group, and the first nozzle in the third nozzle group, the arrangement angles of the remaining first nozzles are any combination of 3-6 arrangement angles among the preset 26 arrangement angles, and the number of nozzles corresponding to each arrangement angle is less than or equal to M / m. Wherein, M represents the number of the remaining first nozzles, and m represents the first number of types of arrangement angles selected. It should be noted that the first number of types of arrangement angles selected is determined based on the integrity and uniformity of the coverage area of ​​the containment by the first nozzles on the first spray ring pipe. For example, the number of first nozzles on the first spray ring pipe 81 is 65, and the first number of arrangement angles selected is 3, then the number of nozzles corresponding to each arrangement angle is less than or equal to 21.

[0059] In addition, in one embodiment of the present invention, the second nozzles are evenly distributed on the second spray ring pipe 82, and the second spray ring pipe 82 includes a fourth nozzle group and a fifth nozzle group, and the number of second nozzles in the fourth nozzle group and the number of second nozzles in the fifth nozzle group satisfy 9:16. For example, the number of second nozzles on the second spray ring pipe 82 is 100. Among them, the number of second nozzles in the fourth nozzle group is 36, and the number of second nozzles in the fifth nozzle group is 64.

[0060] Further, the arrangement angle of the second nozzle located first in the clockwise / counterclockwise direction in the fourth nozzle group is 0°, and the arrangement angle of the second nozzle located first in the same direction in the fifth nozzle group is 10°. For example, the arrangement angle of the second nozzle located first in the clockwise direction in the fourth nozzle group is 0°, and the arrangement angle of the second nozzle located first in the clockwise direction in the fifth nozzle group is 10°.

[0061] Furthermore, in the second spray ring pipe 82, excluding the first nozzle in the fourth nozzle group and the first nozzle in the fifth nozzle group, the arrangement angles of the remaining second nozzles are any combination of 3-6 arrangement angles among the preset 26 arrangement angles, and the number of nozzles corresponding to each arrangement angle is less than or equal to N / n. Wherein, N represents the number of the remaining second nozzles, and n represents the second number of types of the selected arrangement angles. It should be noted that the second number of types of the selected arrangement angles is determined based on the integrity and uniformity of the coverage area of ​​the containment by the second nozzles on the second spray ring pipe. For example, the number of second nozzles on the second spray ring pipe 82 is 98, and the first number of the selected arrangement angles is 3, then the number of nozzles corresponding to each arrangement angle is less than or equal to 32.

[0062] It should be noted that if Figure 2 As shown, the diameter direction of the first spray ring tube 81 or the second spray ring tube 82 where the nozzle is located is taken as the horizontal direction, the horizontal direction pointing to the center of the first spray ring tube or the center of the second spray ring tube is taken as the first horizontal direction, the horizontal direction pointing to the opposite direction of the center of the first spray ring tube or the center of the second spray ring tube is taken as the second horizontal direction, and the vertical direction is taken as the direction perpendicular to the ground. The 26 preset arrangement angles include the angle type between the first horizontal direction and the vertical direction, and the angle type between the second horizontal direction and the vertical direction, and the angle types include 0°, 7.5°, 15°, 30°, 40°, 45°50°, 60°, 70°, 75°, 80°, 90°, and 120°.

[0063] In addition, the arrangement angle of the first nozzle in the first nozzle group, the arrangement angle of the first nozzle in the second nozzle group, and the arrangement angle of the first nozzle in the third nozzle group are all angles between the first horizontal direction and the vertical direction, or the angle between the second horizontal direction and the vertical direction; the arrangement angle of the second nozzle in the first nozzle group and the arrangement angle of the second nozzle in the first nozzle group are all angles between the first horizontal direction and the vertical direction, or the angle between the second horizontal direction and the vertical direction.

[0064] Therefore, by arranging the first nozzle on the first spray ring pipe and the second nozzle on the second spray ring pipe, it is ensured that the cooling medium sprayed from the spray header can fully cover the containment, effectively reducing the radioactivity of the atmosphere in the containment after the accident, and making the flow rate sprayed from the spray header into the containment change as evenly as possible over time, thereby improving the safety and reliability of the nuclear power plant.

[0065] Furthermore, the gas tank 2 is cylindrical, and the top of the gas tank 2 is semi-ellipsoidal. The cylindrical tank body is evenly stressed and has high strength under the internal pressure, and can be used in high-pressure environments after accidents. An outlet pipeline is provided on the top of the gas tank 2 to facilitate connection with the gas supply pipeline, safety valve interface, etc.

[0066] Furthermore, the expandable gas is nitrogen, and the volume of nitrogen in the gas storage tank 2 is 5-15m 3 The pressure of nitrogen in the gas storage tank 2 is not less than 4-15MPa, so as to overcome the back pressure of the containment and the resistance of the pipeline network, and ensure that the expanded gas can inject all the cooling medium of the water storage tank into the containment.

[0067] Furthermore, the cooling medium is deionized water, which has extremely low conductivity and can effectively prevent corrosion and contamination of the pipelines in the passive containment spray system, ensuring the safe operation of the system. The volume of the water storage tank 7 is 100-200m 3 , providing sufficient cooling medium reserve for accident handling. The design pressure in the water storage tank 7 is lower than 8MPa, so it can withstand normal storage and delivery pressure.

[0068] Furthermore, if Figure 1 As shown, the spray system also includes an active spray interface 12, which is arranged in the containment 1. The active spray interface 12 is connected to the pipeline between the check valve 11 and the containment penetration piece 9, so that the active spray can be started according to the accident situation, and multiple safety functions can be exerted to control the consequences of the accident, further protect the integrity of the reactor containment and prevent the leakage of radioactive substances.

[0069] By applying the technical solution in the above embodiment of the present invention, the following technical effects are achieved:

[0070] 1. The passive containment spray system does not rely on a power device, but relies on a pressure storage method to drive the system to operate. It is suitable for removing radioactivity from the containment after an accident, thereby reducing the radioactivity released into the environment and improving the safety and reliability of the nuclear power plant.

[0071] 2. The passive containment spray system separates the gas storage tank and the water storage tank through a split design, which can significantly reduce the volume and pressure of the water storage tank. It is also equipped with a pressure reducing orifice plate, which can balance the flow of the passive containment spray system and extend the spray time to meet the preset spray time requirements.

[0072] 3. The passive containment spray system is provided with a heat exchange water tank, which can retain the radioactive substances in the liquid sprayed into the containment in the heat exchange water tank, thereby reducing the radioactive substances in the atmosphere of the containment, thereby reducing the dose released into the environment and improving the safety of the nuclear power plant.

[0073] 4. The passive containment spray system is provided with a spray header, which includes a first spray ring pipe and a second spray ring pipe. By arranging a first nozzle on the first spray ring pipe and a second nozzle on the second spray ring pipe, it is ensured that the cooling medium sprayed from the spray header can fully cover the containment, effectively reducing the radioactivity of the atmosphere in the containment after the accident.

[0074] The above are only a number of specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0075] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0076] It should be noted that, in the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

Claims

1. A passive containment spray system, characterized in that: The spray system comprises: A gas storage tank (2), a pneumatic isolation valve (3), a pressure-reducing orifice plate (4), and an external isolation valve (5) are arranged outside the containment shell (1) and connected via pipelines. A control module (6), the control module (6) being in communication with the pneumatic isolation valve (3) and the outer-shell isolation valve (5); A water storage tank (7) and a spray header (8) arranged in the containment shell (1), wherein the water storage tank (7) is in communication with the pressure-reducing orifice plate (4), the water storage tank (7) can contain a cooling medium, and the water storage tank (7) is in communication with the spray header (8) via the outer-shell isolation valve (5); The gas storage tank (2) can contain expandable gas, and the expandable gas reaches the water storage tank (7) after passing through the pneumatic isolation valve (3) and the pressure reduction orifice plate (4). The expandable gas drives the cooling medium to flow through the spray header (8).

2. The spray system according to claim 1, characterized in that: The spray header (8) comprises a first spray ring pipe (81) and a second spray ring pipe (82). The first spray ring pipe (81) and the second spray ring pipe (82) are arranged in sequence in a direction perpendicular to the ground. The first spray ring pipe (81) is arranged above the second spray ring pipe (82). One side of the first spray ring pipe (81) is connected to one side of the second spray ring pipe (82) through a pipeline. The other side of the first spray ring pipe (81) is connected to the other side of the second spray ring pipe (82) through a pipeline. The pipeline passing through the containment penetration piece (9) is respectively connected to both sides of the first spray ring pipe (81) and both sides of the second spray ring pipe (82).

3. The spray system according to claim 2, characterized in that: The radius of the first spray ring pipe (81) is 4-6 m, and the radius of the second spray ring pipe (82) is 14-15 m.

4. The spray system according to claim 2, characterized in that: The number of nozzles arranged on the spray header (8) is greater than or equal to 168, the number of first nozzles on the first spray ring pipe (81) is greater than or equal to 68, and the number of second nozzles on the second spray ring pipe (82) is greater than or equal to 100.

5. The spray system according to claim 4, characterized in that: The first spray heads are evenly distributed on the first spray ring tube (81), the first spray ring tube (81) comprises a first spray head group, a second spray head group and a third spray head group, the number of first spray heads in the first spray head group, the number of first spray heads in the second spray head group and the number of first spray heads in the third spray head group satisfy 2:6:

9.

6. The spray system according to claim 5, characterized in that: The arrangement angle of the first nozzle located first in the first nozzle group along the clockwise / counterclockwise direction is 0°, the arrangement angle of the first nozzle located first in the second nozzle group along the same direction is 7.5°, and the arrangement angle of the first nozzle located first in the third nozzle group along the same direction is 0°.

7. The spray system according to claim 6, characterized in that: In the first spray ring tube (81), excluding the first nozzle in the first nozzle group, the first nozzle in the second nozzle group and the first nozzle in the third nozzle group, the arrangement angles of the remaining first nozzles are any combination of 3 to 6 arrangement angles among the preset 26 arrangement angles, and the number of nozzles corresponding to each arrangement angle is less than or equal to M / m, wherein M represents the number of the remaining first nozzles and m represents the first type number of the selected arrangement angles.

8. The spray system according to claim 4, characterized in that: The second spray heads are evenly distributed on the second spray ring pipe (82), the second spray ring pipe (82) comprises a fourth spray head group and a fifth spray head group, and the number of second spray heads in the fourth spray head group and the number of second spray heads in the fifth spray head group satisfy 9:

16.

9. The spray system according to claim 8, characterized in that: The arrangement angle of the second nozzle located first in the clockwise / counterclockwise direction in the fourth nozzle group is 0°, and the arrangement angle of the second nozzle located first in the fifth nozzle group along the same direction is 10°.

10. The spray system according to claim 9, characterized in that: In the second spray ring tube (82), excluding the first nozzle in the fourth nozzle group and the first nozzle in the fifth nozzle group, the arrangement angles of the remaining second nozzles are a combination of any 3-6 arrangement angles among the preset 26 arrangement angles, and the number of nozzles corresponding to each arrangement angle is less than or equal to N / n, wherein N represents the number of the remaining second nozzles and n represents the second type number of the selected arrangement angles.

11. The spray system according to claim 7 or 10, characterized in that: The diameter direction of the first spray ring tube (81) or the second spray ring tube (82) where the spray head is located is taken as the horizontal direction, the horizontal direction pointing to the center of the first spray ring tube or the center of the second spray ring tube is taken as the first horizontal direction, the horizontal direction pointing to the opposite direction of the center of the first spray ring tube or the center of the second spray ring tube is taken as the second horizontal direction, and the direction perpendicular to the ground is taken as the vertical direction. The 26 preset arrangement angles include the angle type between the first horizontal direction and the vertical direction, and the angle type between the second horizontal direction and the vertical direction, and the angle type includes 0°, 7.5°, 15°, 30°, 40°, 45°, 50°, 60°, 70°, 75°, 80°, 90°, and 120°.

12. The spray system according to claim 4, characterized in that: The nozzle is an open nozzle, the spray flow rate of the nozzle is less than or equal to 2kg / h, and the spray angle of the nozzle is less than or equal to 65°.

13. The spray system according to claim 1, characterized in that: The pressure reducing orifice plate (4) is a single-stage orifice plate, and the inner aperture of the pressure reducing orifice plate (4) is 60-80 mm.

14. The spray system according to claim 1, characterized in that: The spray system further comprises a heat exchange water tank (10) arranged in the containment shell (1), wherein alkaline water is stored in the heat exchange water tank (10).

15. The spray system according to claim 1, characterized in that: The gas storage tank (2) is cylindrical, the top of the gas storage tank (2) is semi-ellipsoidal, and an outlet pipeline is arranged on the top of the gas storage tank (2).

16. The spray system according to claim 1, characterized in that: The expandable gas is nitrogen, and the volume of the nitrogen in the gas storage tank (2) is 5-15m 3 , the pressure of nitrogen in the gas storage tank (2) is not less than 4-15MPa.

17. The spray system according to claim 2, characterized in that: The spray system further comprises a check valve (11) arranged in the containment shell (1), the number of the external isolation valves (5) being at least two and the at least two external isolation valves (5) being arranged in parallel, and the check valve (11) and the at least two external isolation valves (5) forming an isolation valve group of the containment shell (1).

18. The spray system according to claim 17, characterized in that: The spray system further comprises an active spray interface (12), wherein the active spray interface (12) is arranged in the containment shell (1), and the active spray interface (12) is connected to a pipeline between the check valve (11) and the containment shell penetration piece (9).

19. The spray system according to claim 1, characterized in that: The cooling medium is deionized water, and the volume of the water storage tank (7) is 100-200m 3 , the design pressure in the water storage tank (7) is lower than 8 MPa.

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