Master pneumatic valve control circuit, passive injection control system and method for nuclear power plant

Abstract

The application provides a main pneumatic valve control circuit, a passive injection control system and method for a nuclear power plant. The main pneumatic valve control circuit comprises a control pipeline, one end of which is branched to form a first branch, a second branch, a third branch and a fourth branch. The first branch, the second branch and the third branch are connected in parallel and one end of each of them is connected to a gas source. The other end of each of them is connected to one end of the fourth branch. The other end of the fourth branch is connected to a main pneumatic valve. A first electromagnetic valve is arranged on the first branch to control the opening and closing of the first branch. A second electromagnetic valve is arranged on the second branch to control the opening and closing of the second branch. A third electromagnetic valve is arranged at the intersection of the first branch, the third branch and the fourth branch. The third electromagnetic valve is arranged in the first branch and is used to control the opening and closing of the first branch and the fourth branch. A fourth electromagnetic valve is arranged at the intersection of the second branch, the third branch and the fourth branch. The fourth electromagnetic valve is arranged in the second branch and is used to control the opening and closing of the second branch and the fourth branch.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plant safety system technology, specifically to a main pneumatic valve control circuit, a passive safety injection control system and method for nuclear power plants. Background Technology

[0002] The reliability of nuclear power unit generation is the foundation for ensuring the economic viability of a nuclear power plant; long-term safe and stable operation can bring substantial benefits. Generation reliability relies on the stable and reliable operation of all power generation systems and equipment within the plant, especially critical systems and equipment. Generation reliability is a key factor in the strong competitiveness of nuclear power units, therefore, research on improving the generation reliability of nuclear power plants is of paramount importance.

[0003] In the nuclear power industry, equipment that causes unplanned shutdowns or reactor stoppages due to a single fault is called a single point of failure equipment. The failure of a single point of failure equipment can directly lead to reactor shutdown or activation of dedicated safety systems. Its reliability plays an extremely critical role in the safe and stable operation of the unit.

[0004] Unplanned shutdowns and reactor stoppages are closely related to the failure of single-point-of-failure equipment. The reliability of the equipment directly determines the number of unplanned shutdowns and reactor stoppages at nuclear power plants, and directly affects the nuclear safety and power generation of nuclear power plants.

[0005] According to statistics, unplanned shutdowns and reactor stoppages at nuclear power plants account for over 70% of all such incidents due to the failure of a single piece of equipment. Unexpected actions or degraded driving forces of passive safety systems directly impact the execution of the unit's safety functions.

[0006] To enhance the safety of the unit, nuclear power units typically use fail-safe pneumatic valves as the driving device for the passive safety injection system. For example, if the solenoid valve controlling the gas supply to the pneumatic valve loses power, the pneumatic valve will open, the passive safety injection system will activate, and the power plant will be placed in a safe state. However, this can also directly cause unplanned shutdowns of the unit, affecting the reliability of power generation.

[0007] Based on this, the inventors of this application propose a main pneumatic valve control circuit, a passive safety injection control system and method for nuclear power plants, in order to solve one or more of the above-mentioned technical problems. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the defect of existing safety pneumatic valves that may cause unplanned reactor shutdowns, and to provide a main pneumatic valve control circuit, a passive safety injection control system and method for nuclear power plants.

[0009] The present invention solves the above-mentioned technical problems through the following technical solution:

[0010] The first aspect of the present invention provides a main pneumatic valve control circuit, comprising:

[0011] The control pipeline branches at one end into a first branch, a second branch, a third branch, and a fourth branch. The first, second, and third branches are connected in parallel, with one end converging and connecting to the air source, and the other end converging and connecting to one end of the fourth branch. The other end of the fourth branch is connected to the main pneumatic valve.

[0012] A first solenoid valve is provided on the first branch to control its on / off state, a second solenoid valve is provided on the second branch to control its on / off state, a third solenoid valve is provided at the junction of the first branch, the third branch and the fourth branch, the third solenoid valve is located in the first branch and is used to control the on / off state of the first branch and the fourth branch; a fourth solenoid valve is provided at the junction of the second branch, the third branch and the fourth branch, the fourth solenoid valve is located in the second branch and is used to control the on / off state of the second branch and the fourth branch.

[0013] When both the third solenoid valve and the fourth solenoid valve are energized, the third solenoid valve and the fourth solenoid valve retract into the first branch and the second branch, so that the third branch and the fourth branch are connected.

[0014] When both the third solenoid valve and the fourth solenoid valve are de-energized, the third solenoid valve and the fourth solenoid valve cooperate to block the third branch and the fourth branch, so that the first branch and the second branch are connected to the fourth branch.

[0015] When one of the third and fourth solenoid valves is energized while the other is de-energized, the third and fourth branches are blocked, and the first or second branch is connected to the fourth branch.

[0016] According to one embodiment of the present invention, the first solenoid valve is provided with a first exhaust port, one end of which is connected to the first branch. When the first solenoid valve is energized, the first exhaust port is closed to the first branch, and the first branch is in an inflatable state. When the first solenoid valve is de-energized, the first exhaust port is connected to the first branch, and the first branch is in an exhaustable state.

[0017] The second solenoid valve has a second vent port, one end of which is connected to the second branch. When the second solenoid valve is energized, the second vent port is closed to the second branch, and the second branch is in an inflatable state. When the second solenoid valve is de-energized, the second vent port is connected to the second branch, and the second branch is in an ventable state.

[0018] The third solenoid valve has a third exhaust port. When the third solenoid valve is energized, the first branch is blocked. When the third solenoid valve is de-energized, the first branch is connected to the fourth branch.

[0019] The fourth solenoid valve has a fourth exhaust port. When the fourth solenoid valve is energized, the second branch is blocked. When the fourth solenoid valve is de-energized, the second branch is connected to the fourth branch.

[0020] According to one embodiment of the present invention, the control pipeline is provided with a pressure-reducing orifice plate upstream of the branch, the pressure-reducing orifice plate being used to reduce the gas pressure injected into the first branch, the second branch, the third branch and the fourth branch.

[0021] A second aspect of the present invention provides a passive safety injection control system for nuclear power plants, comprising:

[0022] The safety injection tank is connected to the reactor via a first connection flow path at its outlet.

[0023] The first connecting flow path is provided with a main pneumatic valve, one end of which is connected to the main pneumatic valve control circuit as described above. The main pneumatic valve control circuit is used to control the opening and closing of the main pneumatic valve.

[0024] According to one embodiment of the present invention, the inlet end of the safety injection tank is connected to the main pipeline of the reactor through a second connecting flow path, and an inlet isolation valve is provided on the second connecting flow path.

[0025] According to one embodiment of the present invention, a pressure boosting component is provided at the connection point between the second connecting flow path and the main pipeline, and the pressure boosting component extends at least partially into the main pipeline.

[0026] According to one embodiment of the present invention, the pressurizing component is a baffle plate, which is arc-shaped and arranged in the flow direction of the main pipeline.

[0027] According to one embodiment of the present invention, the first connecting flow path is further provided with a check valve downstream of the main pneumatic valve, the check valve being used to prevent backflow in the first connecting flow path.

[0028] According to one embodiment of the present invention, the main pneumatic valve and the main pump of the reactor are communicatively connected.

[0029] A third aspect of the present invention also provides a passive safety injection control method for a nuclear power plant, employing the passive safety injection control system for nuclear power plants as described above, the control method comprising:

[0030] A main pneumatic valve is installed on the first connection flow path of the injection box; wherein, the main pneumatic valve is controlled to open and close through a main pneumatic valve control circuit.

[0031] The positive and progressive effects of this invention are as follows:

[0032] The main pneumatic valve control circuit of this invention controls the opening and closing of the main pneumatic valve, which can avoid the problem of a single solenoid valve power failure triggering the passive safety system. It prevents the adverse effects on reactor operation and passive safety injection caused by valve mis-opening or normal driving. Moreover, the installation of a first, second, third and fourth solenoid valve on the control pipeline will not affect the valve response under accident conditions, ensuring the operational safety and reliability of the nuclear power plant. Attached Figure Description

[0033] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0034] Figure 1 This is a schematic diagram of the control principle structure of the main pneumatic valve control circuit of the present invention;

[0035] Figure 2 This is a control principle diagram of the main pneumatic valve control circuit of the present invention;

[0036] Figures 3a to 3e The control principle structure diagram of the air supply valve group corresponding to the main pneumatic valve when it is closed;

[0037] Figures 4a to 4e The control principle diagram of the air supply valve group corresponding to the main pneumatic valve when it is closed;

[0038] Figures 5a to 5e The control principle structure diagram of the air supply valve group corresponding to the main pneumatic valve when it is open;

[0039] Figures 6a to 6e The control principle diagram of the air supply valve group corresponding to the main pneumatic valve when it is closed;

[0040] Figure 7 This is a schematic diagram of the passive safety injection control system for nuclear power plants according to the present invention.

[0041] 1. Control piping; 11. First branch; 12. Second branch; 13. Third branch; 14. Fourth branch; 15. Pressure reducing orifice plate;

[0042] 2. First solenoid valve; 21. First exhaust port;

[0043] 3. Second solenoid valve; 31. Second exhaust port;

[0044] 4. Third solenoid valve; 41. Third exhaust port;

[0045] 5. Fourth solenoid valve; 51. Fourth exhaust port;

[0046] 6. Injection tank; 61. First connecting flow path; 62. Main pneumatic valve; 63. Second connecting flow path; 64. Pressure booster; 65. Inlet isolation valve; 66. Check valve;

[0047] 7. Reactor; 71. Main pipeline; 72. Main pump. Detailed Implementation

[0048] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0050] Reference Figure 1 and Figure 2 This invention proposes a main pneumatic valve control circuit, which includes a control pipeline 1. One end of the control pipeline 1 branches into a first branch 11, a second branch 12, a third branch 13, and a fourth branch 14. The first branch 11, the second branch 12, and the third branch 13 are connected in parallel, with one end converging and connecting to an air source, and the other end converging and connecting to one end of the fourth branch 14. The other end of the fourth branch 14 is connected to the main pneumatic valve 62. The first branch 11 is equipped with a first control valve for its on / off state. Solenoid valve 2; a second solenoid valve 3 is provided on the second branch 12 to control its on / off state; a third solenoid valve 4 is provided at the junction of the first branch 11, the third branch 13 and the fourth branch 14; the third solenoid valve 4 is located in the first branch 11 and is used to control the on / off state of the first branch 11 and the fourth branch 14; a fourth solenoid valve 5 is provided at the junction of the second branch 12, the third branch 13 and the fourth branch 14; the fourth solenoid valve 5 is located in the second branch 12 and is used to control the on / off state of the second branch 12 and the fourth branch 14.

[0051] Specifically, when both the third solenoid valve 4 and the fourth solenoid valve 5 are energized, they retract into the first branch 11 and the second branch 12, thereby connecting the third branch 13 and the fourth branch 14. When both the third solenoid valve 4 and the fourth solenoid valve 5 are de-energized, they cooperate to block the third branch 13 and the fourth branch 14, thereby connecting the first branch 11 and the second branch 12 with the fourth branch 14. When one of the third solenoid valve 4 and the fourth solenoid valve 5 is energized while the other is de-energized, the third branch 13 and the fourth branch 14 are blocked, and either the first branch 11 or the second branch 12 is connected to the fourth branch 14.

[0052] The control pipeline 1 of this application is equipped with a first solenoid valve 2, a second solenoid valve 3, a third solenoid valve 4 and a fourth solenoid valve 5. The de-energization of any of the solenoid valves will not cause the main pneumatic valve 62 to lose its air supply, thereby avoiding the main pneumatic valve 62 from losing its air supply and actuating due to the power failure of a single power source, and ensuring the safety of the nuclear power plant and the reliability of power generation.

[0053] Furthermore, the first solenoid valve 2 is provided with a first exhaust port 21, one end of which is connected to the first branch 11. When the first solenoid valve 2 is energized, the first exhaust port 21 is closed to the first branch 11, and the first branch 11 is in an inflatable state. When the first solenoid valve 2 is de-energized, the first exhaust port 21 is connected to the first branch 11, and the first branch 11 is in an exhaustable state.

[0054] The second solenoid valve 3 has a second exhaust port 31, one end of which is connected to the second branch 12. When the second solenoid valve 3 is energized, the second exhaust port 31 is closed to the second branch 12, and the second branch 12 is in an inflatable state. When the second solenoid valve 3 is de-energized, the second exhaust port 31 is connected to the second branch 12, and the second branch 12 is in an exhaustable state.

[0055] The third solenoid valve 4 has a third exhaust port 41. When the third solenoid valve 4 is energized, the first branch 11 is blocked. When the third solenoid valve 4 is de-energized, the first branch 11 is connected to the fourth branch 14.

[0056] The fourth solenoid valve 5 has a fourth exhaust port 51. When the fourth solenoid valve 5 is energized, the second branch 12 is blocked. When the fourth solenoid valve 5 is de-energized, the second branch 12 is connected to the fourth branch 14.

[0057] Furthermore, the control line 1 is provided with a pressure reducing orifice plate 15 upstream of the diversion line. The pressure reducing orifice plate 15 is used to reduce the air pressure injected into the first branch 11, the second branch 12, the third branch 13 and the fourth branch 14.

[0058] The following can be used as a reference. Figures 3a to 3e as well as Figures 4a to 4eThe operating principle of the main pneumatic valve 62 during normal operation of reactor 7 and main pump 72 is explained in detail:

[0059] Please refer to Figure 3a and Figure 4a When the first solenoid valve 2, the second solenoid valve 3, the third solenoid valve 4 and the fourth solenoid valve 5 are all energized, the first branch 11 and the second branch 12 are blocked, the third branch 13 and the fourth branch 14 are connected and supply air to the main pneumatic valve 62, at which time the main pneumatic valve 62 is closed.

[0060] When the first solenoid valve 2 is de-energized and the others are energized, refer to Figure 3b and Figure 4b The first branch 11 and the second branch 12 are blocked, the third branch 13 and the fourth branch 14 are connected and supply air to the main pneumatic valve 62, at which time the main pneumatic valve 62 is closed.

[0061] When the second solenoid valve 3 is de-energized and the others are energized, refer to... Figure 3c and Figure 4c The first branch 11 and the second branch 12 are blocked, the third branch 13 and the fourth branch 14 are connected and supply air to the main pneumatic valve 62, at which time the main pneumatic valve 62 is closed.

[0062] When the third solenoid valve 4 is de-energized and the others are energized, refer to... Figure 3d and Figure 4d The first branch 11 and the third branch 13 are blocked, the second branch 12 and the fourth branch 14 are connected and supply air to the main pneumatic valve 62, at which time the main pneumatic valve 62 is closed.

[0063] When the fourth solenoid valve 5 is de-energized and the others are energized, refer to... Figure 3e and Figure 4e The second branch 12 and the third branch 13 are blocked, the first branch 11 is connected to the fourth branch 14 and supplies air to the main pneumatic valve 62, at which time the main pneumatic valve 62 is closed.

[0064] In other words, the de-energization of any one of the first solenoid valve 2, the second solenoid valve 3, the third solenoid valve 4, and the fourth solenoid valve 5 will not cause the main pneumatic valve 62 to lose its air supply, thus avoiding the problem of the main pneumatic valve 62 losing its air supply and triggering the passive safety system to operate directly due to the de-energization of a single power source.

[0065] Please refer to Figures 5a to 5e and Figures 6a to 6e In case of an accident requiring the main pneumatic valve 62 to be opened for exhaust, the first solenoid valve 2, the second solenoid valve 3, the third solenoid valve 4, and the fourth solenoid valve 5 can be de-energized, as per the corresponding instructions. Figure 5a and Figure 6aAt this time, the first branch 11, the second branch 12 and the third branch 13 are all blocked, and the third exhaust port 41 and the fourth exhaust port 51 are both open. The main pneumatic valve 62 exhausts through the fourth branch 14 to the first exhaust port 21 of the first solenoid valve 2 at the first branch 11 and to the second exhaust port 31 of the second solenoid valve 3 at the second branch 12 through the third exhaust port 41 and the fourth exhaust port 51 respectively. The main pneumatic valve 62 is opened for exhaust.

[0066] When the first solenoid valve 2 is energized while the second solenoid valve 3, the third solenoid valve 4, and the fourth solenoid valve 5 are de-energized, refer to the corresponding... Figure 5b and Figure 6b At this time, the second branch 12 and the third branch 13 are blocked. The main pneumatic valve 62 exhausts gas through the fourth branch 14 along the second branch 12 to the second exhaust port 31 of the second solenoid valve 3, and the main pneumatic valve 62 opens for exhaust. It can be seen that the first solenoid valve 2 is open at this time, but the intake pressure through the first branch 11 is less than the exhaust pressure. Therefore, the gas flowing through the first branch 11 to the fourth branch 14 flows along the fourth branch 14 to the second branch 12, and is finally discharged through the second exhaust port 31 of the second solenoid valve 3.

[0067] When the second solenoid valve 3 is energized while the first solenoid valve 2, the third solenoid valve 4, and the fourth solenoid valve 5 are de-energized, refer to the corresponding... Figure 5c and Figure 6c At this time, the first branch 11 and the third branch 13 are blocked, and the main pneumatic valve 62 exhausts gas through the fourth branch 14 along the first branch 11 to the first exhaust port 21 of the first solenoid valve 2, and the main pneumatic valve 62 opens to exhaust gas. It can be seen that the gas flowing through the second branch 12 to the fourth branch 14 flows together with the fourth branch 14 to the first exhaust port 21 for discharge.

[0068] When the third solenoid valve 4 is energized while the first solenoid valve 2, the second solenoid valve 3, and the fourth solenoid valve 5 are de-energized, refer to the corresponding... Figure 5d and Figure 6d At this time, the first branch 11, the second branch 12 and the third branch 13 are blocked, and the main pneumatic valve 62 exhausts through the fourth branch 14 along the second branch 12 to the second exhaust port 31 of the second solenoid valve 3, and the main pneumatic valve 62 opens to exhaust.

[0069] When the fourth solenoid valve 5 is energized while the first solenoid valve 2, the second solenoid valve 3, and the third solenoid valve 4 are de-energized, refer to the corresponding... Figure 5e and Figure 6e At this time, the first branch 11, the second branch 12 and the third branch 13 are blocked, and the main pneumatic valve 62 exhausts through the fourth branch 14 along the first branch 11 to the first exhaust port 21 of the first solenoid valve 2, and the main pneumatic valve 62 opens to exhaust.

[0070] In other words, when the main pneumatic valve 62 needs to exhaust gas, the failure of any solenoid valve to de-energize will not directly lead to the interruption of exhaust gas, thereby improving the control reliability and operational stability of the pneumatic valve.

[0071] Please refer to Figure 7 The present invention also proposes a passive safety injection control system for a nuclear power plant, including a safety injection tank 6, the outlet end of which is connected to the reactor 7 via a first connecting flow path 61; a main pneumatic valve 62 is provided on the first connecting flow path 61, one end of which is connected to the above-mentioned main pneumatic valve control circuit, which is used to control the opening and closing of the main pneumatic valve 62.

[0072] In one embodiment, the inlet end of the injection tank 6 is connected to the main pipe 71 of the reactor 7 via a second connecting flow path 63, and an inlet isolation valve 65 is provided on the second connecting flow path 63.

[0073] Specifically, a pressure booster 64 is provided at the connection point between the second connecting flow path 63 and the main pipe 71, and the pressure booster 64 extends at least partially into the main pipe 71.

[0074] By installing a pressure booster 64 at the main pipe 71 in the second connecting flow path 63, the dynamic pressure of the flow velocity is converted into static pressure using the principle of fluid mechanics, so that the injection system always maintains a positive driving force and avoids reverse leakage of the main pneumatic valve 62 due to reverse pressure difference.

[0075] Optionally, the pressurizing component 64 is a stop baffle, which is arranged in an arc shape facing the flow direction of the main pipe 71.

[0076] The arc-shaped stop plate can guide the fluid in the main pipe 71, allowing the water in the main pipe 71 to flow into the second connecting flow path 63. In some other embodiments, the shape and size of the stop member are not limited here. One end of the stop member can be integrally set with the pipe corresponding to the second connecting flow path 63, or it can be installed in the second connecting flow path 63 by bonding or welding. There are no limitations here.

[0077] The first connecting flow path 61 is also provided with a check valve 66 downstream of the main pneumatic valve 62. The check valve 66 is used to prevent backflow in the first connecting flow path 61.

[0078] The check valve 66 is used to ensure that the fluid in the safety injection tank 6 can flow unidirectionally to the reactor 7 in the event of an accident, while the high-pressure fluid on the reactor 7 side will not flow back to the safety injection tank 6 during normal operation.

[0079] In addition, this application also includes control logic for shutting down reactor 7 and main pump 72 by means of a main pneumatic valve 62 opening signal. That is, the main pneumatic valve 62 is communicatively connected to reactor 7 and main pump 72, thereby preventing adverse effects on reactor 7 operation and passive safety injection from accidental valve opening or normal operation.

[0080] This invention also proposes a passive safety injection control method for nuclear power plants, employing the above-mentioned passive safety injection control system for nuclear power plants. The control method includes:

[0081] A main pneumatic valve is installed on the first connecting flow path of the injection box; wherein, the main pneumatic valve is controlled to open and close through the main pneumatic valve control circuit.

[0082] Using the above control method, during gas supply, the main pneumatic valve will not lose its gas supply if any solenoid valve is de-energized, thus avoiding the passive safety control action triggered by the main pneumatic valve losing its gas supply due to a single power supply failure.

[0083] When the main pneumatic valve needs to vent, any three solenoid valves are de-energized. Even if one of the solenoid valves is accidentally energized, it will not affect the venting of the main pneumatic valve, thus ensuring the normal operation of the passive safety system.

[0084] This design can prevent adverse effects on reactor operation and passive safety injection caused by accidental valve opening or normal valve actuation, thus improving the operational safety and reliability of nuclear power plants.

[0085] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation", "connection", "joining", and "fixing" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can also refer to mechanical connections. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0086] This application uses specific terms to describe embodiments of the application. Terms such as "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0087] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A main pneumatic valve control circuit, characterized in that, include: The control pipeline branches at one end into a first branch, a second branch, a third branch, and a fourth branch. The first, second, and third branches are connected in parallel, with one end converging and connecting to the air source, and the other end converging and connecting to one end of the fourth branch. The other end of the fourth branch is connected to the main pneumatic valve. A first solenoid valve is provided on the first branch to control its on / off state, a second solenoid valve is provided on the second branch to control its on / off state, a third solenoid valve is provided at the junction of the first branch, the third branch and the fourth branch, the third solenoid valve is located in the first branch and is used to control the on / off state of the first branch and the fourth branch; a fourth solenoid valve is provided at the junction of the second branch, the third branch and the fourth branch, the fourth solenoid valve is located in the second branch and is used to control the on / off state of the second branch and the fourth branch. When both the third solenoid valve and the fourth solenoid valve are energized, the third solenoid valve and the fourth solenoid valve retract into the first branch and the second branch, so that the third branch and the fourth branch are connected. When both the third solenoid valve and the fourth solenoid valve are de-energized, the third solenoid valve and the fourth solenoid valve cooperate to block the third branch and the fourth branch, so that the first branch and the second branch are connected to the fourth branch. When one of the third and fourth solenoid valves is energized while the other is de-energized, the third and fourth branches are blocked, and the first or second branch is connected to the fourth branch.

2. The main pneumatic valve control circuit according to claim 1, characterized in that, The first solenoid valve is provided with a first exhaust port, one end of which is connected to the first branch. When the first solenoid valve is energized, the first exhaust port is closed to the first branch, and the first branch is in an inflatable state. When the first solenoid valve is de-energized, the first exhaust port is connected to the first branch, and the first branch is in an exhaustable state. The second solenoid valve has a second vent port, one end of which is connected to the second branch. When the second solenoid valve is energized, the second vent port is closed to the second branch, and the second branch is in an inflatable state. When the second solenoid valve is de-energized, the second vent port is connected to the second branch, and the second branch is in an ventable state. The third solenoid valve has a third exhaust port. When the third solenoid valve is energized, the first branch is blocked. When the third solenoid valve is de-energized, the first branch is connected to the fourth branch. The fourth solenoid valve has a fourth exhaust port. When the fourth solenoid valve is energized, the second branch is blocked. When the fourth solenoid valve is de-energized, the second branch is connected to the fourth branch.

3. The main pneumatic valve control circuit according to claim 1, characterized in that, The control pipeline is equipped with a pressure-reducing orifice plate upstream of the branch line. The pressure-reducing orifice plate is used to reduce the gas pressure injected into the first branch, the second branch, the third branch and the fourth branch.

4. A passive safety injection control system for a nuclear power plant, characterized in that, include: The safety injection tank is connected to the reactor via a first connection flow path at its outlet. The first connecting flow path is provided with a main pneumatic valve, one end of which is connected to a main pneumatic valve control circuit as described in any one of claims 1-3, and the main pneumatic valve control circuit is used to control the opening and closing of the main pneumatic valve.

5. The passive safety injection control system for nuclear power plants according to claim 4, characterized in that, The inlet of the safety injection tank is connected to the main pipeline of the reactor through a second connecting flow path, and an inlet isolation valve is provided on the second connecting flow path.

6. The passive safety injection control system for nuclear power plants according to claim 5, characterized in that, A pressure booster is provided at the connection point between the second connecting flow path and the main pipeline, and the pressure booster extends at least partially into the main pipeline.

7. The passive safety injection control system for nuclear power plants according to claim 6, characterized in that, The pressurizing component is a baffle plate, which is arc-shaped and oriented toward the flow direction of the main pipeline.

8. The passive safety injection control system for nuclear power plants according to claim 4, characterized in that, The first connection flow path is also provided with a check valve downstream of the main pneumatic valve, the check valve being used to prevent backflow in the first connection flow path.

9. The passive safety injection control system for nuclear power plants according to claim 4, characterized in that, The main pneumatic valve and the main pump of the reactor are connected in communication.

10. A passive safety injection control method for a nuclear power plant, characterized in that, The passive safety injection control system for nuclear power plants as described in any one of claims 4-9, wherein the control method comprises: A main pneumatic valve is installed on the first connection flow path of the injection box; wherein, the main pneumatic valve is controlled to open and close through a main pneumatic valve control circuit.

Images