Nuclear power plant primary loop pressure relief valve group and nuclear power plant primary loop system

Abstract

This invention discloses a primary loop depressurization valve assembly and a primary loop system for a nuclear power plant. It enables the main valve to automatically open under certain primary loop conditions and maintain its open state continuously. It also enables manual opening of the main valve and ensures effective isolation of the main valve during normal operation and refueling shutdown. The nuclear power plant primary loop depressurization valve assembly includes a main valve (2), a first two-position three-way valve (3), and a second two-position three-way valve (4). The main valve (2) includes a main valve body (1) and a valve core. The first two-position three-way valve (3) can switch between a first state and a second state, and the second two-position three-way valve (4) can switch between a third state and a fourth state to change the medium and pressure entering the sealing cavity (215). The medium entering the sealing cavity (215) opens the pressure setting value P of the valve cavity (24). 0main Satisfy: P0 < P 0main <P acc .

Description

Technical Field

[0001] This invention relates to the field of nuclear power technology, specifically to a primary loop depressurization valve assembly and a primary loop system for a nuclear power plant. Background Technology

[0002] In pressurized water reactor nuclear power plants, the reactor coolant system, as one of the most important barriers to contain radioactive materials, is directly related to the safety performance of the nuclear power plant.

[0003] Nuclear power plant reactor coolant systems operate at high pressures during normal operation. To prevent overpressure in the event of an accident and to ensure continuous cooling of the reactor core after an accident, overpressure protection valves and primary loop pressure relief valves are required in the reactor coolant system. Currently, the main types of overpressure protection valves and pressure relief valves used are as follows, and their advantages and disadvantages are as follows:

[0004] (1) Spring-loaded safety valve: It automatically opens to relieve pressure when the system pressure reaches the set pressure of the safety valve. It is currently the most widely used overpressure protection valve in process systems. The characteristic of this type of safety valve is that it can only perform overpressure protection function. When the pressure is lower than the opening pressure, the valve closes and cannot be opened manually.

[0005] (2) Pilot-operated safety valve, similar to spring-loaded safety valve, automatically opens to relieve pressure when the system pressure reaches the set pressure of the safety valve. It has higher reliability than spring-loaded safety valve and is currently mainly used in pressure regulator safety valves. This type of safety valve requires less power to open. The disadvantage is that when it needs to be opened manually, it needs to be kept energized at all times, and it cannot be kept open at low pressure.

[0006] (3) Electric or pneumatic isolation valves, which open or close via power supply when the system pressure reaches the design requirement. The advantage of this type of valve is that it can be opened at any time and maintains its original state after the power is lost. The disadvantage is that it requires a large amount of power to open.

[0007] (4) Explosive valve: The valve opening signal triggers the explosive unit inside the valve, generating high-pressure gas that drives the piston inside the valve. During the impact motion, the shear cover of the valve's flow path can be cut off, thereby connecting the valve inlet and outlet and realizing the safety function of system depressurization. The characteristic of this type of valve is that once opened, it always remains open and cannot be reversed. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art by providing a primary loop depressurization valve group and a primary loop system for nuclear power plants. This system can realize the automatic opening of the main valve under the conditions of the primary loop and maintain it in the open state, as well as the manual opening of the main valve and ensure the effective isolation of the main valve during normal operation and refueling shutdown.

[0009] In a first aspect, embodiments of the present invention provide a primary loop pressure relief valve assembly for a nuclear power plant, comprising a main valve, a first two-position three-way valve, and a second two-position three-way valve. The main valve includes a main valve body and a valve core. The main valve body has a sealing cavity and a valve cavity, the valve cavity being used to connect the primary loop coolant to the atmosphere. The power end of the valve core is located within the sealing cavity, and the sealing end is located within the valve cavity. The valve core can slide within the main valve body under the pressure of the medium within the sealing cavity to open or close the opening of the valve cavity. The first two-position three-way valve has a first input port, a second input port, and a first output port. The first input port is connected to the primary loop coolant, and the second input port is connected to a constant pressure source. The first two-position three-way valve has a first state and a second state; in the first state, the first input port is connected to the first output port; in the second state, the second input port is connected to the first output port. The second two-position three-way valve has a third input port, a fourth input port, and a second output port. The third input port is connected to an atmospheric pressure source, the fourth input port is connected to the first output port, and the second output port is connected to the sealed cavity. The second two-position three-way valve has a third state and a fourth state. In the third state, the third input port is connected to the second output port; in the fourth state, the fourth input port is connected to the second output port. The first two-position three-way valve can switch between the first state and the second state, and the second two-position three-way valve can switch between the third state and the fourth state to change the medium and pressure entering the sealed cavity. The medium entering the sealed cavity opens the pressure set value P of the valve cavity. 0main Satisfy: P < P 0main <P acc Where P is atmospheric pressure, P acc The pressure of the constant pressure source.

[0010] In some embodiments, the first two-position three-way valve includes a first valve body, a first control piston assembly, and a first drive assembly; the first valve body has a first inner cavity, and the first input port, the second input port, and the first output port are all disposed on the side wall of the first valve body and communicate with the first inner cavity; the first control piston assembly is located in the first inner cavity and forms a first communicating cavity with the side wall of the first valve body, and the first drive assembly can drive the first control piston assembly to move to change the position of the first communicating cavity, so that the first two-position three-way valve switches between a first state and a second state; in the first state, the first input port and the first output port are both communicated with the first communicating cavity; in the second state, the second input port and the first output port are both communicated with the first communicating cavity. The second two-position three-way valve includes a second valve body, a second control piston assembly, and a second drive assembly. The second valve body has a second inner cavity. The third input port, the fourth input port, and the second output port are all disposed on the side wall of the second valve body and communicate with the second inner cavity. The second control piston assembly is located in the second inner cavity and forms a second communicating cavity with the side wall of the second valve body. The second drive assembly can drive the second control piston assembly to move to change the position of the second communicating cavity, so that the second two-position three-way valve switches between a third state and a fourth state. In the third state, both the third input port and the second output port communicate with the second communicating cavity. In the fourth state, both the fourth input port and the second output port communicate with the second communicating cavity.

[0011] In some embodiments, the first control piston assembly includes a first control piston rod and a plurality of first control pistons fixed to the first control piston rod. The plurality of first control pistons are sequentially and slidably disposed within the first inner cavity along the axial direction of the first control piston rod to divide the first inner cavity into a first communicating cavity and first isolation cavities located on both sides of the first communicating cavity. The first drive assembly includes a first coil, a second coil, and a first drive block. The first coil and the second coil are sequentially arranged along the axial direction of the first control piston rod, and the first drive block is fixedly connected to the first control piston rod. When the first coil is energized and the second coil is de-energized, the first coil drives the first drive block to move along a first direction, and drives the first control piston rod to move along the first direction, so that the first two-position three-way valve switches to a first state, and the second input port communicates with the first isolation cavity. When the second coil is energized and the first coil is de-energized, the second coil drives the first drive block to move along a second direction, and drives the first control piston rod to move along the second direction, so that the first two-position three-way valve switches to a second state, and the first input port communicates with the first isolation cavity. The second control piston assembly includes a second control piston rod and a plurality of second control pistons fixed to the second control piston rod. The plurality of second control pistons are sequentially and slidably disposed within the second inner cavity along the axial direction of the second control piston rod to divide the second inner cavity into a second communicating cavity and second isolation cavities located on both sides of the second communicating cavity. The second drive assembly includes a third coil, a fourth coil, and a second drive block. The third coil and the fourth coil are sequentially arranged along the axial direction of the second control piston rod, and the second drive block is fixedly connected to the second control piston rod. When the third coil is energized and the fourth coil is de-energized, the third coil drives the second drive block to move along a third direction, and drives the second control piston rod to move along a third direction, so that the second two-position three-way valve switches to a third state, and the fourth input port communicates with the second isolation cavity. When the fourth coil is energized and the third coil is de-energized, the fourth coil drives the second drive block to move along a fourth direction, and drives the second control piston rod to move along a fourth direction, so that the second two-position three-way valve switches to a fourth state, and the third input port communicates with the first isolation cavity. Wherein, the first direction and the second direction are two opposite directions on the axis of the first control piston rod, and the third direction and the fourth direction are two opposite directions on the axis of the second control piston rod.

[0012] In some embodiments, the first two-position three-way valve and the second two-position three-way valve are arranged side by side, the axis of the first control piston rod coincides with the axis of the second control piston rod, and the second end of the first control piston rod is disposed opposite to the first end of the second control piston rod. The first coil, the second coil, and the first drive block are all disposed near the first end of the first control piston rod, and the third coil, the fourth coil, and the second drive block are all disposed near the second end of the second control piston rod. When the first two-position three-way valve is in a first state and the second two-position three-way valve is in a third state, the second end of the first control piston rod abuts against the first end of the second control piston rod. When the first two-position three-way valve is in a second state and the second two-position three-way valve is in a fourth state, the second end of the first control piston rod abuts against the first end of the second control piston rod.

[0013] In some embodiments, the first two-position three-way valve and the second two-position three-way valve are disposed at different heights, or the first two-position three-way valve and the second two-position three-way valve are disposed at the same height but separated from each other. The first coil and the second coil are respectively located at both ends of the first control piston rod; there are two first drive blocks, one of which is fixedly connected to the first end of the first control piston rod, and the other of which is fixedly connected to the second end of the first control piston rod. The third coil and the fourth coil are respectively located at both ends of the first control piston rod; there are two second drive blocks, one of which is connected to the first end of the second control piston rod, and the other of which is fixedly connected to the second end of the second control piston rod.

[0014] In some embodiments, the primary loop depressurization valve assembly of a nuclear power plant further includes a rotary switch, which includes a moving contact and a plurality of stationary contacts. The moving contact is electrically connected to a power source, and the moving contact can also be electrically connected to one of the plurality of stationary contacts; the plurality of stationary contacts are sequentially electrically connected to the second coil, the first coil, the fourth coil, and the third coil, respectively.

[0015] In some embodiments, an empty contact is provided between two adjacent stationary contacts.

[0016] In some embodiments, the primary loop depressurization valve assembly of a nuclear power plant further includes a control component, which includes a pressure sensor and a controller. The pressure sensor is located at the inlet of the valve chamber and is used to monitor the pressure P of the cooling medium entering the valve chamber. rcs and outputs pressure P rcs The controller receives the pressure signal and sets P... rcs With P 0main P accA comparison is made to obtain a comparison result, and a valve status adjustment suggestion is given based on the comparison result; the operator controls the first two-position three-way valve and the second two-position three-way valve according to the valve status adjustment suggestion. When the comparison result is P... 0main <P rcs In cases where the main valve does not need to be opened, the controller provides a first valve state adjustment suggestion. The operator, based on this suggestion, switches the first two-position three-way valve to the first state and the second two-position three-way valve to the fourth state, thereby placing the nuclear power plant primary loop depressurization valve group in the first isolation state; or, when the comparison result is P... rcs <P acc In cases where the main valve does not need to be opened, the controller provides a second valve state adjustment suggestion. The operator, based on this suggestion, switches the first two-position three-way valve to the second state and the second two-position three-way valve to the fourth state, thereby placing the nuclear power plant primary loop depressurization valve group in the second isolation state; or, when the comparison result is P... 0main >P rcs In the event that the main valve needs to be opened, the controller provides a third valve status adjustment suggestion. The operator, based on this suggestion, switches the first two-position three-way valve to the first state and the second two-position three-way valve to the fourth state, so that the nuclear power plant primary loop depressurization valve group is in the first open state; or, in P... rcs In any situation where the main valve needs to be opened, the controller provides a fourth valve status adjustment suggestion. The operator switches the second two-position three-way valve to the third state according to the fourth valve status adjustment suggestion, so that the nuclear power plant primary loop depressurization valve group is in the second open state.

[0017] In some embodiments, P acc The value range is 1MPa-5MPa.

[0018] In some embodiments, the valve core includes a main piston assembly and a main spring. The main piston assembly includes a main piston rod, a main piston, and a valve disc. The main piston rod slides within the main valve body. The main piston is fixed to the main piston rod and located within the sealing cavity. The valve disc is fixed to the main piston rod and located within the valve cavity. The main spring is located within the sealing cavity and compressed between the main piston and the bottom wall of the sealing cavity. The medium entering the sealing cavity opens the pressure setting value P of the valve cavity. 0main Also satisfies: P 0main ×(A1-A2)+G=F, where A1 is the cross-sectional area of ​​the main piston, A2 is the cross-sectional area of ​​the valve disc, G is the weight of the main piston assembly, and F is the elastic force of the main spring when the valve chamber is closed.

[0019] Therefore, the nuclear power plant primary loop depressurization valve assembly provided in this embodiment of the invention can adjust the pressure of the medium entering the sealed cavity by allowing the first two-position three-way valve to switch between the first and second states, and the second two-position three-way valve to switch between the third and fourth states. By setting a sealed cavity and a valve cavity in the main valve, and allowing the valve core to slide within the main valve body under the pressure of the medium entering the sealed cavity, the opening and closing of the main valve can be controlled by controlling the pressure of the medium delivered to the sealed cavity. This enables the main valve to automatically open and always remain open under the conditions met in the primary loop, and also enables manual opening of the main valve and ensures effective isolation of the main valve during normal operation and refueling shutdown.

[0020] Secondly, embodiments of the present invention also provide a primary loop system for a nuclear power plant, comprising a primary loop system body, a depressurization pipeline, and a primary loop depressurization valve assembly as described in the first aspect. The primary loop system body is located within the containment. The depressurization pipeline is connected to the primary loop system body. The primary loop depressurization valve assembly is disposed on the depressurization pipeline.

[0021] Thirdly, embodiments of the present invention also provide an isolation method for a nuclear power plant primary loop system, wherein the nuclear power plant primary loop system is the nuclear power plant primary loop system of the second aspect, and the method includes: monitoring the pressure P at the inlet of the valve chamber of the nuclear power plant primary loop pressure relief valve assembly. rcs ; P rcs With P 0main P acc The comparison results are obtained, and corresponding valve status adjustment suggestions are given based on the comparison results. The operator switches the nuclear power plant primary loop depressurization valve group to the first isolation state or the second isolation state according to the valve status adjustment suggestions.

[0022] In some embodiments, switching the nuclear power plant primary loop depressurization valve group to a first isolation state or a second isolation state based on the comparison result includes: when the comparison result is P 0main <P rcs In the event of a first valve state adjustment suggestion, the operator controls the first two-position three-way valve to switch to the first state, and controls the second two-position three-way valve to switch to the fourth state, so that the nuclear power plant primary loop pressure relief valve group is in the first isolation state; or, if the comparison result is P rcs <P acc In the event of a second valve status adjustment suggestion, the operator controls the first two-position three-way valve to switch to the second state according to the second valve status adjustment suggestion, and controls the second two-position three-way valve to switch to the fourth state, so that the nuclear power plant primary loop depressurization valve group is in the second isolation state.

[0023] Fourthly, embodiments of the present invention also provide a depressurization method for a primary loop system of a nuclear power plant, wherein the primary loop system is the same as the primary loop system of the nuclear power plant in the second aspect, and the method includes: monitoring the pressure P at the inlet of the valve chamber of the primary loop depressurization valve assembly of the nuclear power plant. rcs ; P rcs With P 0main P acc The comparison results are obtained, and corresponding valve status adjustment suggestions are given based on the comparison results. The operator switches the nuclear power plant primary loop depressurization valve group to the first open state or the second open state according to the valve status adjustment suggestions.

[0024] In some embodiments, switching the nuclear power plant primary loop depressurization valve group to a first open state or a second open state based on the comparison result includes: when the comparison result is P 0main >P rcs In the event of a third valve status adjustment suggestion, the operator controls the first two-position three-way valve to switch to the first state, and controls the second two-position three-way valve to switch to the fourth state, so that the nuclear power plant primary loop pressure relief valve group is in the first open state; or, in P rcs Under any circumstances, a fourth valve status adjustment suggestion is given. The operator controls the second two-position three-way valve to switch to the third state according to the fourth valve status adjustment suggestion, so that the nuclear power plant primary loop depressurization valve group is in the second open state.

[0025] The nuclear power plant primary loop system, the isolation method for the nuclear power plant primary loop system, and the depressurization method for the nuclear power plant primary loop system provided in this embodiment of the invention have the same beneficial effects as the aforementioned nuclear power plant primary loop depressurization valve group, and will not be repeated here. Attached Figure Description

[0026] Figure 1 : A schematic diagram of the passive core cooling system;

[0027] Figure 2 : A structural diagram of a primary loop pressure relief valve assembly in a nuclear power plant provided by an embodiment of the present invention;

[0028] Figure 3 : A structural diagram of a first two-position three-way valve and a second two-position three-way valve (first isolation state or first open state) provided for embodiments of the present invention;

[0029] Figure 4 : A structural diagram of another first two-position three-way valve and a second two-position three-way valve provided in an embodiment of the present invention (second open state);

[0030] Figure 5 : A structural diagram of another first two-position three-way valve and a second two-position three-way valve provided in the embodiments of the present invention (second isolation state);

[0031] Figure 6 : A structural diagram of another first two-position three-way valve and a second two-position three-way valve provided in the embodiments of the present invention;

[0032] Figure 7 : A structural diagram of a rotary switch provided in an embodiment of the present invention. Detailed Implementation

[0033] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0034] Example 1:

[0035] Passive core cooling is one of the technical routes for third-generation pressurized water reactor nuclear power technology. Taking the AP1000 as an example, such as... Figure 1 As shown, its passive core cooling system includes:

[0036] Core makeup water tank: The pressure is the same as that of the primary loop (15.5MPa), and it is responsible for the function of making the core makeup water under high pressure.

[0037] Water supply tank: around 4-5MPa, responsible for water replenishment when the pressure is below 4-5MPa.

[0038] IRWST (Gravity Water Tank): The pressure is the same as atmospheric pressure, as low as 0.1MPa, and it is responsible for replenishing water when the pressure of the primary circuit drops to normal pressure.

[0039] ADS valves (explosion valves): They perform the pressure relief function, gradually reducing the primary circuit pressure from 15.5 to atmospheric pressure, enabling the three water replenishment measures mentioned above to be activated in sequence, ultimately achieving IRWST gravity water injection, which is necessary for long-term core cooling and ensuring long-term safety.

[0040] To avoid problems caused by excessively rapid depressurization, ADS1-3 and ADS-4 were put into operation in sequence.

[0041] Among them, ADS1-3 has a relatively low depressurization speed and mainly undertakes the function of depressurization under high pressure.

[0042] The ADS-4 depressurizes quickly, so it can only be opened after the primary circuit pressure is below a certain threshold (approximately 8-9 MPa).

[0043] After ADS-4 is activated, the primary circuit pressure can quickly drop to the pressure of the injection tank, and eventually drop to the IRWST injection pressure.

[0044] Current ADS technology primarily employs rupture valves and electric valves. Both types of valves open by manually triggering a signal or by outputting an electrical signal when the pressure in the primary circuit drops to a threshold. Electric valves, due to their large size and high energy requirement for opening, present numerous challenges in the design of pressure relief systems. Rupture valves offer advantages such as good sealing and low opening power, but certain reliability issues remain.

[0045] Based on this, such as Figure 2 As shown, this embodiment of the invention provides a primary loop depressurization valve assembly for a nuclear power plant, which can be manually opened and maintain primary loop isolation when needed. The nuclear power plant primary loop depressurization valve assembly includes a main valve 2, a first two-position three-way valve 3, and a second two-position three-way valve 4. The main valve 2 includes a main valve body 1 and a valve core. The main valve body 1 has a sealing cavity 215 and a valve cavity 24. The valve cavity 24 is used to connect the primary loop coolant to the atmosphere. The power end of the valve core is located in the sealing cavity 215, and the sealing end is located in the valve cavity 24. The valve core can slide within the main valve body 1 under the pressure of the medium in the sealing cavity 215 to open or close the opening of the valve cavity 24.

[0046] That is, by controlling the pressure of the medium delivered to the sealing cavity 215, the opening and closing of the main valve 2 can be controlled.

[0047] The first two-position three-way valve 3 has a first inlet 311, a second inlet 312, and a first outlet 313. The first inlet 311 is connected to the primary coolant circuit, and the second inlet 312 is connected to a constant pressure source. The first two-position three-way valve 3 has a first state and a second state; in the first state, the first inlet 311 is connected to the first outlet 313; in the second state, the second inlet 312 is connected to the first outlet 313. The second two-position three-way valve 4 has a third inlet 411, a fourth inlet 412, and a second outlet 413. The third inlet 411 is connected to an atmospheric pressure source, the fourth inlet 412 is connected to the first outlet 313, and the second outlet 413 is connected to a sealing cavity 215. The second two-position three-way valve 4 has a third state and a fourth state; in the third state, the third inlet 411 is connected to the second outlet 413; in the fourth state, the fourth inlet 412 is connected to the second outlet 413. The first two-position three-way valve 3 can switch between the first and second states, and the second two-position three-way valve 4 can switch between the third and fourth states to change the medium and pressure entering the sealing chamber 215. The medium entering the sealing chamber 215 opens the pressure set value P of the valve chamber 24. 0main Satisfy: P0 < P 0main <P acc Where P0 is atmospheric pressure, P acc The pressure of the constant pressure source.

[0048] In some examples, Pacc The value range is 1MPa-5MPa.

[0049] For example, the second input port 312 can be connected to the injection box, and the constant pressure source P acc The value is the pressure of the injection box.

[0050] For example, P acc The value can be 1MPa, 4MPa, 4.5MPa or 5MPa, etc.

[0051] The following describes the operation of the primary loop pressure relief valve assembly in a nuclear power plant under different operating conditions. The pressure of the primary loop coolant is marked as P. rcs .

[0052] When the primary circuit pressure is normal (approximately 15.5 MPa), such as Figure 3 As shown, the first two-position three-way valve 3 is switched to the first state, and the second two-position three-way valve 4 is switched to the fourth state. At this time, the first input port 311, the first output port 313, the fourth input port 412, and the second output port 413 are connected to the sealing cavity 215. The sealing cavity 215 of the main valve 2 contains the pressure P of the primary circuit coolant. rcs It is much larger than the main valve 2 opening set value P. 0main When main valve 2 is closed, it achieves isolation of main valve 2 during normal operation of the primary circuit, i.e., the first isolation state. This isolation occurs when a fault occurs in the primary circuit until the pressure is less than the main valve 2 opening setpoint P. 0main When the pressure in the primary circuit is abnormal, the main valve 2 automatically opens and remains open, thus realizing the automatic opening of the main valve 2 when the pressure in the primary circuit is abnormal, i.e., the first opening state.

[0053] In the event of a primary circuit failure leading to a pressure drop to 8-9 MPa, if main valve 2 needs to be manually opened, such as... Figure 4 As shown, the second two-position three-way valve 4 is switched to the third state. At this time, the first two-position three-way valve 3 can be in any state. The third input port 411 and the second output port 413 are connected to the sealing cavity 215. The pressure in the sealing cavity 215 of the main valve 2 is atmospheric pressure P0, which is lower than the opening setting value P of the main valve 2. 0main This causes the main valve 2 to open, i.e., the second open state.

[0054] When it is undesirable for main valve 2 to open during a shutdown and refueling process (which requires reducing the primary circuit pressure to atmospheric pressure), the primary circuit pressure P... rcs Decrease to P 0main -P acc In between, such as Figure 5As shown, the first two-position three-way valve 3 is switched to the second state, and the second two-position three-way valve 4 is switched to the fourth state. At this time, the second input port 312, the first output port 313, the fourth input port 412, and the second output port 413 are connected to the sealing cavity 215. The sealing cavity 215 of the main valve 2 is under constant pressure (such as the pressure of the injection tank, which is about 4 MPa), which is greater than the opening setting value P of the main valve 2. 0main When main valve 2 is closed, the isolation of main valve 2 under low pressure conditions in the primary circuit is achieved, i.e., the second isolation state.

[0055] Therefore, the nuclear power plant primary loop depressurization valve group provided in this embodiment of the invention can adjust the pressure of the medium entering the sealing cavity 215 by allowing the first two-position three-way valve 3 to switch between the first state and the second state, and the second two-position three-way valve 4 to switch between the third state and the fourth state. By setting a sealing cavity 215 and a valve cavity 24 in the main valve 2, and allowing the valve core to slide in the main valve body under the pressure of the medium entering the sealing cavity 215, the opening and closing of the main valve 2 can be controlled by controlling the pressure of the medium delivered to the sealing cavity 215. This enables the main valve 2 to automatically open and always maintain the open state under the conditions of the primary loop, and also enables manual opening of the main valve 2 and effective isolation of the main valve 2 during normal operation and reactor shutdown for refueling.

[0056] In some embodiments, the first two-position three-way valve 3 includes a first valve body 30, a first control piston assembly, and a first drive assembly. The first valve body 30 has a first inner cavity, and a first input port 311, a second input port 312, and a first output port 313 are all disposed on the side wall of the first valve body 30 and communicate with the first inner cavity. The first control piston assembly is located in the first inner cavity and forms a first communicating cavity 31 with the side wall of the first valve body 30. The first drive assembly can drive the first control piston assembly to move to change the position of the first communicating cavity, so that the first two-position three-way valve 3 switches between a first state and a second state. In the first state, the first input port 311 and the first output port 313 are both connected to the first communicating cavity 31. In the second state, the second input port 312 and the first output port 313 are both connected to the first communicating cavity 31.

[0057] In the first state, the first output port 313 of the first two-position three-way valve 3 is connected to the first input port 311, and the pressure of the medium connected to the first input port 311 is output through the first two-position three-way valve 3. In the second state, the second input port 312 of the first two-position three-way valve 3 is connected to the first input port 311, and the pressure of the medium connected to the second input port 312 is output through the first two-position three-way valve 3.

[0058] With the above settings, the state of the first two-position three-way valve 3 can be changed by altering the position of the first connecting cavity, thereby adjusting the pressure of the medium output by the first two-position three-way valve 3.

[0059] The second two-position three-way valve 4 includes a second valve body 40, a second control piston assembly, and a second drive assembly. The second valve body 40 has a second inner cavity. A third input port 411, a fourth input port 412, and a second output port 413 are all disposed on the side wall of the second valve body 40 and are all in communication with the second inner cavity. The second control piston assembly is located in the second inner cavity and forms a second communication cavity 41 with the side wall of the second valve body 40. The second drive assembly can drive the second control piston assembly to move to change the position of the second communication cavity, so that the second two-position three-way valve 4 switches between a third state and a fourth state. In the third state, the third input port 411 and the second output port 413 are both in communication with the second communication cavity 41. In the fourth state, the fourth input port 412 and the second output port 413 are both in communication with the second communication cavity 41.

[0060] In the third state, the third input port 411 of the second two-position three-way valve 4 is connected to the second output port 413, and the pressure of the medium connected through the third input port 411 is output through the second two-position three-way valve 4. In the second state, the fourth input port 412 of the second two-position three-way valve 4 is connected to the second output port 413, and the pressure of the medium connected through the fourth input port 412 is output through the second two-position three-way valve 4.

[0061] With the above settings, the state of the second two-position three-way valve 4 can be changed by altering the position of the second connecting cavity, thereby adjusting the pressure of the medium output by the second two-position three-way valve 4.

[0062] In some embodiments, such as Figure 2As shown, the first control piston assembly includes a first control piston rod 32 and a plurality of first control pistons 33 fixed on the first control piston rod 32. The plurality of first control pistons 33 are sequentially and sealed in the first inner cavity along the axial direction of the first control piston rod 32 to divide the first inner cavity into a first connecting cavity 31 and a first isolation cavity located on both sides of the first connecting cavity 31. The first driving assembly includes a first coil 301, a second coil 302, and a first driving block 303. The first coil 301 and the second coil 302 are arranged sequentially along the axial direction of the first control piston rod 32. The first driving block 303 is fixedly connected to the first control piston rod 32. When the first coil 301 is energized and the second coil 302 is de-energized, the first coil 301 drives the first driving block 303 to move along the first direction X, and drives the first control piston rod 32 to move along the first direction X, so that the first two-position three-way valve 3 switches to the first state, and the second input port 312 communicates with the first isolation chamber. When the second coil 302 is energized and the first coil 301 is de-energized, the second coil 302 drives the first driving block 303 to move along the second direction Y, and drives the first control piston rod 32 to move along the second direction Y, so that the first two-position three-way valve 3 switches to the second state, and the first input port 311 communicates with the first isolation chamber. The first direction X and the second direction Y are two opposite directions on the axis of the first control piston rod 32.

[0063] For example, the number of first control pistons 33 is four.

[0064] like Figure 2 As shown, the first isolation chamber is a closed cavity. When the first input port 311 or the second input port 312 is connected to the first isolation chamber, it can offset the pressure generated by the medium entering the first isolation chamber on the side wall of the first isolation chamber in multiple directions, thereby avoiding the axial force brought to the first control piston rod 32 by the pressure difference of different input ports.

[0065] like Figure 2 As shown, when the first coil 301 is energized and the second coil 302 is de-energized, the first coil 301 will generate an attractive force on the first driving block 303, thereby driving the first driving block 303 to move along the first direction X. When the second coil 302 is energized and the first coil 301 is de-energized, the second coil 302 will generate an attractive force on the first driving block 303, thereby driving the first driving block 303 to move along the second direction Y.

[0066] Furthermore, in this embodiment, the first coil 301 or the second coil 302 only needs to be energized when the first control piston rod 32 needs to be activated, requiring less energy input. After the first control piston rod 32 is activated, even if the first coil 301 or the second coil 302 is de-energized, the position of the first control piston rod 32 can be maintained, thereby keeping the primary loop depressurization valve group of the nuclear power plant in a set state in the event of a power outage, ensuring the safety of the nuclear power plant.

[0067] In some examples, the first drive component can also be a linear motor, etc.

[0068] like Figure 2 As shown, the second control piston assembly includes a second control piston rod 42 and a plurality of second control pistons 43 fixed on the second control piston rod 42. The plurality of second control pistons 43 are sequentially and sealed in the second inner cavity along the axial direction of the second control piston rod 42 to divide the second inner cavity into a second connecting cavity 41 and a second isolation cavity located on both sides of the second connecting cavity 41. The second drive assembly includes a third coil 401, a fourth coil 402, and a second drive block 403. The third coil 401 and the fourth coil 402 are arranged sequentially along the axial direction of the second control piston rod 42, and the second drive block 403 is fixedly connected to the second control piston rod 42. When the third coil 401 is energized and the fourth coil 402 is de-energized, the third coil 401 drives the second drive block 403 to move along a third direction M, and drives the second control piston rod 42 to move along a third direction M, so that the second two-position three-way valve 4 switches to the third state, and the fourth input port 412 communicates with the second isolation chamber. When the fourth coil 402 is energized and the third coil 401 is de-energized, the fourth coil 402 drives the second drive block 403 to move along a fourth direction N, and drives the second control piston rod 42 to move along a fourth direction N, so that the second two-position three-way valve 4 switches to the fourth state, and the third input port 411 communicates with the first isolation chamber. The third direction M and the fourth direction N are two opposite directions on the axis of the second control piston rod 42.

[0069] For example, the number of second control pistons 43 is four.

[0070] like Figure 2 As shown, the third isolation chamber is a closed cavity. When the third input port 411 or the fourth input port 412 is connected to the third isolation chamber, the pressure generated by the medium entering the third isolation chamber on the side wall of the third isolation chamber can be offset in multiple directions, thereby avoiding the axial force on the second control piston rod 42 caused by the pressure difference between different input ports.

[0071] like Figure 2 As shown, when the third coil 401 is energized and the fourth coil 402 is de-energized, the third coil 401 will generate an attractive force on the second driving block 403, thereby driving the second driving block 403 to move along the third direction M. When the fourth coil 402 is energized and the third coil 401 is de-energized, the fourth coil 402 will generate an attractive force on the second driving block 403, thereby driving the second driving block 403 to move along the fourth direction N.

[0072] Furthermore, in the second drive assembly, the third coil 401 or the fourth coil 402 only needs to be energized when the second control piston rod 42 needs to be activated, requiring less energy input. After the second control piston rod 42 has been activated, even if the third coil 401 or the fourth coil 402 is de-energized, the second control piston rod 42 can maintain its current position, thereby keeping the primary loop depressurization valve group of the nuclear power plant in the set state in the event of a power outage, ensuring the safety of the nuclear power plant.

[0073] In some examples, the second drive component can also be a linear motor, etc.

[0074] Furthermore, Table 1 shows a comparison of the advantages and disadvantages of the nuclear power plant primary loop pressure relief valve assembly of the present invention with several overpressure protection valves and pressure relief valves commonly used in the field of nuclear power safety mentioned in the background art.

[0075] Table 1

[0076]

[0077] In some embodiments, such as Figure 2 As shown, the first two-position three-way valve 3 and the second two-position three-way valve 4 are arranged side by side. The axis of the first control piston rod 32 coincides with the axis of the second control piston rod 42, and the second end of the first control piston rod 32 is positioned opposite to the first end of the second control piston rod 42. The first coil 301, the second coil 302, and the first drive block 303 are all positioned close to the first end of the first control piston rod 32, and the third coil 401, the fourth coil 402, and the second drive block 403 are all positioned close to the second end of the second control piston rod 42. When the first two-position three-way valve 3 is in the first state and the second two-position three-way valve 4 is in the third state, the second end of the first control piston rod 32 abuts against the first end of the second control piston rod 42. When the first two-position three-way valve 3 is in the second state and the second two-position three-way valve 4 is in the fourth state, the second end of the first control piston rod 32 abuts against the first end of the second control piston rod 42.

[0078] Understandably, at this time, such as Figure 2 As shown, the first direction X, the second direction Y, the third direction M, and the fourth direction N are on the same straight line, and the first direction X and the third direction M are the same, and the second direction Y and the fourth direction N are the same.

[0079] The first two-position three-way valve 3 and the second two-position three-way valve 4 are arranged side by side, which makes the arrangement of the first two-position three-way valve 3 and the second two-position three-way valve 4 more compact.

[0080] Furthermore, combined Figure 4 and Figure 5 The first two-position three-way valve 3 and the second two-position three-way valve 4 need to be controlled by Figure 4 The state shown is transformed into Figure 5 In the state shown, it is only necessary to energize the second coil 302. At this time, the second coil 302 will drive the first control piston rod 32 to move in the second direction Y. Since the second end of the first control piston rod 32 abuts against the first end of the second control piston rod 42, the second control piston rod 42 can be pushed by the second end of the first control piston rod 32 to move in the fourth direction N, thereby switching the state of the second two-position three-way valve 4 and realizing the linkage between the first two-position three-way valve 3 and the second two-position three-way valve 4.

[0081] Similarly, the first two-position three-way valve 3 and the second two-position three-way valve 4 need to be controlled by... Figure 5 The state shown is transformed into Figure 4 In the state shown, it is only necessary to energize the third coil 401. At this time, the third coil 401 will drive the second control piston rod 42 to move in the third direction M. Since the second end of the first control piston rod 32 is in contact with the first end of the second control piston rod 42, the first control piston rod 32 can be pushed to move in the first direction X through the first end of the second control piston rod 42, thereby switching the state of the first two-position three-way valve 3 and realizing the linkage between the first two-position three-way valve 3 and the second two-position three-way valve 4.

[0082] Therefore, the number of coils that need to be energized when the first two-position three-way valve 3 and the second two-position three-way valve 4 switch states can be reduced, thereby reducing energy consumption and improving the overall reliability of the primary loop depressurization valve group in the nuclear power plant.

[0083] In some examples, such as Figure 5 As shown, the electromagnetic force of the third coil 401 is greater than that of the second coil 302.

[0084] In this situation, even if the second coil 302 retains some electromagnetic force, the electromagnetic force generated after the third coil 401 is energized can drive the second control piston rod 42 to move in the third direction M, so as to switch the first two-position three-way valve 3 to the first state and the second two-position three-way valve 4 to the third state, so that the main valve 2 is switched to the manual opening state, ensuring that the main valve 2 can be manually opened in any state, thereby improving the overall reliability of the primary loop depressurization valve group of the nuclear power plant.

[0085] In some embodiments, such as Figure 6As shown, the first two-position three-way valve 3 and the second two-position three-way valve 4 are located at different heights, or they are located at the same height but separated from each other. The first coil 301 and the second coil 302 are located at opposite ends of the first control piston rod 32. There are two first drive blocks 303, one fixedly connected to the first end of the first control piston rod 32, and the other fixedly connected to the second end of the first control piston rod 32. The third coil 401 and the fourth coil 402 are located at opposite ends of the first control piston rod 32. There are two second drive blocks 403, one connected to the first end of the second control piston rod 42, and the other fixedly connected to the second end of the second control piston rod 42.

[0086] For example, such as Figure 6 As shown, the first two-position three-way valve 3 and the second two-position three-way valve 4 can be stacked, which can reduce the length of the pipe connecting the first output port 313 and the fourth input port 412.

[0087] Alternatively, the first two-position three-way valve 3 and the second two-position three-way valve 4 can be installed in different locations to make full use of the unused areas within the nuclear power plant.

[0088] The above settings can reduce the overall length of the first two-position three-way valve 3 and the second two-position three-way valve 4, and reduce the interference between the first coil 301 and the second coil 302, as well as the interference between the third coil 401 and the fourth coil 402.

[0089] In some embodiments, such as Figure 7 As shown, the primary loop pressure relief valve assembly of the nuclear power plant also includes a rotary switch 5, which includes a moving contact 501 and multiple stationary contacts. The moving contact 501 is electrically connected to the power supply, and can also be electrically connected to one of the multiple stationary contacts; the multiple stationary contacts are sequentially electrically connected to the second coil 302, the first coil 301, the fourth coil 402, and the third coil 401, respectively.

[0090] For example, such as Figure 7 As shown, when the moving contact 501 is electrically connected to the stationary contact of the corresponding first coil 301, if it is necessary to adjust the moving contact 501 to be electrically connected to the third coil 401, the moving contact 501 needs to be electrically connected to the fourth coil 402 first, and then the moving contact 501 needs to be adjusted to be electrically connected to the third coil 401. The moving contact 501 cannot be directly adjusted to be electrically connected to the third coil 401.

[0091] This design takes into account the matching of the first two-position three-way valve 3 and the second two-position three-way valve 4 with the nuclear power plant status (primary loop system pressure) when switching between different states, to prevent human error. If the switching sequence is disordered, the main valve 2 may be opened by mistake.

[0092] With the above settings, when the rotary switch 5 is turned, only one coil is energized at any given time, avoiding interference between multiple coils and ensuring that the rotary switch 5 controls the state of the first two-position three-way valve 3 and the second two-position three-way valve 4.

[0093] In some embodiments, such as Figure 7 As shown, an empty contact is also provided between two adjacent stationary contacts.

[0094] When the moving contact 501 is in contact with the empty contact, all coils are de-energized.

[0095] In this embodiment of the invention, the first two-position three-way valve 3 and the second two-position three-way valve 4 only require coil energization when activated. After the activation of the first two-position three-way valve 3 and the second two-position three-way valve 4, they can remain in their current state. At this time, the rotary switch 5 can be turned to the empty contact to reduce power loss. Furthermore, the above configuration can maintain the state of the main valve 2 even in the event of a sudden power outage in a nuclear power plant, improving the safety of the nuclear power plant.

[0096] When the rotary switch 5 is turned in sequence, the first coil 301 is energized, the second coil 302, the third coil 401 and the fourth coil 402 are energized and de-energized respectively. The pressure of the medium in the sealing cavity 215 of the main valve 2 and the functions performed by the main valve 2 are shown in Table 2 below.

[0097] Table 2

[0098]

[0099] Functional description of main valve 2:

[0100] Automatic opening: Turn the knob switch 5 until only the fourth coil 402 is energized, or further turn the knob switch 5 until only the first coil 301 is energized, the pressure in the sealed cavity 215 = P rcs The next circuit pressure P after the accident rcs The pressure is reduced from 15.5 MPa to below the opening pressure P of main valve 2. 0main When this happens, main valve 2 can open automatically, i.e., the first open state.

[0101] Manual opening: In certain situations, nuclear power plants require operators to manually open the pressure relief valve. In this case, turn the knob switch 5 until only the third coil 401 is energized, and the pressure in the sealing chamber 215 is P0. At this time, the main valve 2 opens and can always be kept open, i.e., the second open state.

[0102] Isolation under high pressure: During normal operation of a nuclear power plant, the primary circuit pressure P rcs The primary circuit pressure P is 15.5 MPa, under conditions of reactor shutdown and refueling. rcs The pressure gradually decreased from 15.5 MPa to P. 0main During the process of depressurization until atmospheric pressure P0 is reached, when the primary circuit pressure P rcs >P 0main If it is undesirable for main valve 2 to open, it is necessary to isolate main valve 2. In this case, turn the rotary switch 5 to energize only the fourth coil 402, or further turn the rotary switch 5 to energize only the first coil 301. At this time, the pressure in the sealing cavity 215 is P. rcs When Prcs is greater than P 0main At this time, main valve 2 remains closed, i.e., the first isolation state.

[0103] Isolation under low pressure: primary circuit pressure P rcs The pressure gradually decreased from 15.5 MPa to P. 0main During the process of depressurization to atmospheric pressure P0, when the primary circuit pressure P rcs <P acc And further reduced to P 0main When switching to low-pressure isolation mode, turn the knob switch 5 until only the second coil 302 is energized, and the pressure in the sealed cavity 215 is P. acc Because of P acc The pressure is kept constant at 4-5 MPa, which ensures that the main valve 2 is always closed.

[0104] Conversely, during the process of a nuclear power plant transitioning from reactor shutdown and refueling to normal operation, as the primary loop pressure gradually rises from atmospheric pressure P0 to 15.5 MPa, the main valve can be switched sequentially between low-pressure isolation and high-pressure isolation states by rotating a knob.

[0105] The design of the primary loop depressurization valve group in this nuclear power plant, while meeting the primary loop depressurization requirements of the passive safety system, has the following technical advantages:

[0106] 1) Manual opening is possible: The main valve 2 can be manually opened in any state simply by energizing the coil.

[0107] 2) Ensure effective isolation: Ensure effective isolation of main valve 2 under different operating conditions of the power plant.

[0108] 3) Always maintain the open state: After the main valve 2 is opened, it can always maintain the open state without any power supply, ensuring long-term depressurization and long-term recirculation of the primary circuit.

[0109] In some embodiments, the primary loop depressurization valve assembly of a nuclear power plant further includes a control component, which includes a pressure sensor and a controller. The pressure sensor is located at the inlet of valve chamber 24 and is used to monitor the pressure P of the cooling medium entering valve chamber 24. rcs and outputs pressure P rcs The controller receives the pressure signal and sets P... rcs With P 0main P acc A comparison is performed to obtain a comparison result, and corresponding valve status adjustment suggestions are given based on the comparison result. The operator controls the first two-position three-way valve 3 and the second two-position three-way valve 4 according to the valve status adjustment suggestions. When the comparison result is P... 0main <P rcs In the event that main valve 2 does not need to be opened, the controller provides a first valve status adjustment suggestion. The operator, based on this suggestion, switches the first two-position three-way valve 3 to the first state and controls the second two-position three-way valve 4 to the fourth state, thus placing the nuclear power plant's primary loop depressurization valve group in the first isolation state. Alternatively, if the comparison result is P... rcs <P acc In the event that the main valve (2) does not need to be opened, the controller provides a second valve state adjustment suggestion. The operator, based on this suggestion, switches the first two-position three-way valve 3 to the second state and the second two-position three-way valve 4 to the fourth state, so that the nuclear power plant's primary loop depressurization valve group is in the second isolation state. Alternatively, if the comparison result is P... 0main >P rcs In the event that main valve 2 needs to be opened, the controller provides a third valve status adjustment suggestion. The operator, based on this suggestion, switches the first two-position three-way valve 3 to the first position and the second two-position three-way valve 4 to the fourth position, so that the nuclear power plant's primary loop depressurization valve group is in the first open position. Alternatively, in P... rcs Under any circumstances, if it is necessary to open the main valve 2, the controller will provide a fourth valve status adjustment suggestion. The operator will switch the second two-position three-way valve 4 to the third state according to the fourth valve status adjustment suggestion, which can put the nuclear power plant primary loop depressurization valve group in the second open state.

[0110] Understandably, the pressure P of the cooling medium entering valve chamber 24 rcs This refers to the pressure of the primary coolant.

[0111] For example, the controller can be a general-purpose microprocessor with data processing capabilities.

[0112] The comparison result is P. 0main <P rcsIn this situation, after the operator switches the first two-position three-way valve 3 to the first state and the second two-position three-way valve 4 to the fourth state, the pressure at the first output port 313 is P. rcs The pressure at the second output port 413 is P. rcs The pressure P in the sealed cavity is 215. rcs As shown in Table 2 above, the primary loop pressure relief valve of a nuclear power plant can achieve isolation under high pressure, and the first isolation state corresponds to the isolation state under high pressure.

[0113] The comparison result is P. rcs <P acc In this situation, after the operator switches the first two-position three-way valve 3 to the second position and the second two-position three-way valve 4 to the fourth position, the pressure at the first output port 313 is P. acc The pressure at the second output port 413 is P. acc The pressure P in the sealed cavity is 215. acc As shown in Table 2 above, the primary loop depressurization valve group of a nuclear power plant can achieve the isolation function under low pressure, and the first isolation state corresponds to the isolation state under low pressure.

[0114] It should be noted that in P 0main <P rcs <P acc At this time, the primary loop depressurization valve group of the nuclear power plant can be in either the first isolation state or the second isolation state. At this time, the main valve 2 of the primary loop depressurization valve group of the nuclear power plant is closed, which can achieve the isolation of the primary loop.

[0115] The comparison result is P. 0main >P rcs In this situation, after the operator switches the first two-position three-way valve 3 to the first state and the second two-position three-way valve 4 to the fourth state, the pressure at the first output port 313 is P. rcs The pressure at the second output port 413 is P. rcs The pressure P in the sealed cavity is 215. rcs As shown in Table 2 above, the primary circuit depressurization valve group of the nuclear power plant is in the automatic opening state under low pressure, that is, the primary circuit depressurization valve group of the nuclear power plant is in the first opening state.

[0116] In P rcs Under any circumstances, after the operator switches the second two-position three-way valve (4) to the third state, the pressure of the second output port 413 is P0 and the pressure of the sealing cavity 215 is P0. As can be seen from Table 2 above, the nuclear power plant primary circuit depressurization valve group can be manually opened under any state, that is, the nuclear power plant primary circuit depressurization valve group is in the second open state.

[0117] With the above settings, the controller can adjust the pressure P of the cooling medium entering the valve chamber 24. rcsThe system provides suggestions for adjusting valve status, allowing operators to control the status of the first two-position three-way valve 3 and the second two-position three-way valve 4, so that the primary circuit pressure relief valve group of the nuclear power plant is in a high-pressure isolation state, a low-pressure isolation state, a first open state, or a second open state, thereby improving the automation level of the primary circuit pressure relief valve group of the nuclear power plant.

[0118] In some embodiments, such as Figure 2 As shown, in the primary loop pressure relief valve assembly of a nuclear power plant, the valve core includes a main piston assembly and a main spring 26. The main piston assembly includes a main piston rod, a main piston 25, and a valve disc 27. The main piston rod slides within the main valve body 1. The main piston 25 is fixed to the main piston rod and located within the sealing cavity 215. The valve disc 27 is fixed to the main piston rod and located within the valve chamber 24. The main spring 26 is located within the sealing cavity 215 and compressed between the main piston 25 and the bottom wall of the sealing cavity 215. The medium entering the sealing cavity 215 opens the pressure setpoint P of the valve chamber 24. 0main Also satisfies: P 0main ×(A1-A2)+G=F, where A1 is the cross-sectional area of ​​the main piston 25, A2 is the cross-sectional area of ​​the valve disc 27, G is the weight of the main piston assembly, and F is the elastic force of the main spring 26 when the valve chamber 24 is closed.

[0119] When the medium in the sealed cavity 215 is the primary coolant, the pressure P of the primary coolant... rcs Greater than P 0main At this time, the medium in the sealing chamber 215 exerts a relatively large pressure on the main piston 25, which can push the valve disc 27 to close the valve chamber 24. The pressure P of the coolant in the primary circuit... rcs Less than P 0main At this time, the pressure exerted by the medium in the sealing cavity 215 on the main piston 25 is relatively small, and the main spring 26 pushes the valve disc 27 to move upward, thereby opening the valve cavity 24.

[0120] Understandably, P can be adjusted by adjusting the cross-sectional area of ​​the main piston 25, the cross-sectional area of ​​the valve disc 27, the weight of the main piston assembly, and the elastic force of the main spring 26 when the valve chamber 24 is closed. 0main The numerical value is determined, and the opening or closing of the valve chamber 24 is controlled by controlling the pressure of the medium inside the sealing chamber 215.

[0121] Example 2:

[0122] This invention also provides a primary loop system for a nuclear power plant, applied in a nuclear power plant. The primary loop system includes a main body, a depressurization pipeline, and the nuclear power plant primary loop depressurization valve assembly described in Embodiment 1 above. The main body of the primary loop system is located within the containment. The depressurization pipeline is connected to the main body of the primary loop system. The nuclear power plant primary loop depressurization valve assembly is installed on the depressurization pipeline.

[0123] For example, the primary loop system includes a reactor, a steam generator, a main pump, and main piping. Coolant flows through the primary loop system, which is used to heat the secondary loop system through the flow of coolant, thereby driving the generator set of the nuclear power plant to generate electricity.

[0124] For example, the pressure relief pipe is connected to the main pipe.

[0125] When pressure relief is required, the main body of the primary circuit system can be depressurized through the pressure relief pipeline.

[0126] With the above settings, the opening and closing of the depressurization pipeline can be controlled by the depressurization valve group of the nuclear power plant's primary loop, so as to realize the automatic opening of the depressurization pipeline under the conditions of the nuclear power plant's primary loop system and to keep it in the open state at all times. It can also realize the manual opening of the nuclear power plant's primary loop depressurization valve group, and ensure the effective isolation of the nuclear power plant's primary loop depressurization valve group during normal operation and reactor shutdown for refueling.

[0127] Example 3:

[0128] This invention also provides an isolation method for a primary loop system of a nuclear power plant, wherein the primary loop system of the nuclear power plant adopts the primary loop system of the nuclear power plant in Embodiment 2 above, and the method includes: S1-S2.

[0129] S1. Monitor the pressure P at the inlet of valve chamber 24 of the primary loop depressurization valve group in the nuclear power plant. rcs .

[0130] For example, a pressure sensor is installed at the inlet of the valve chamber 24 of the primary loop depressurization valve assembly in a nuclear power plant.

[0131] S2, P rcs With P 0main P acc The comparison results are obtained, and corresponding valve status adjustment suggestions are given based on the comparison results. The operator switches the primary loop depressurization valve group of the nuclear power plant to the first isolation state or the second isolation state according to the valve status adjustment suggestions.

[0132] Step S2 includes:

[0133] The comparison result is P. 0main <P rcs In the event of a situation where a first valve status adjustment suggestion is given, the operator controls the first two-position three-way valve 3 to switch to the first state, and controls the second two-position three-way valve 4 to switch to the fourth state, so that the nuclear power plant primary loop pressure relief valve group is in the first isolation state; or, if the comparison result is P rcs <P accIn the event of a second valve status adjustment suggestion, the operator controls the first two-position three-way valve 3 to switch to the second state, and controls the second two-position three-way valve 4 to switch to the fourth state, so that the nuclear power plant primary loop depressurization valve group is in the second isolation state.

[0134] For example, the first isolation state is the high-pressure isolation state described above, and the second isolation state is the low-pressure isolation state described above.

[0135] The comparison result is P. 0main <P rcs In situations such as when the primary loop system of a nuclear power plant is operating normally, placing the primary loop pressure relief valve group in the first isolation state can keep the primary loop pressure relief valve group closed and prevent it from being accidentally opened during normal operation of the primary loop system.

[0136] The comparison result is P. rcs <P acc In situations such as when the primary loop system of a nuclear power plant is in a shutdown and refueling process, placing the primary loop depressurization valve group in a second isolation state can keep the primary loop depressurization valve group closed, preventing accidental opening of the primary loop depressurization valve group during the shutdown and refueling process.

[0137] The pressure within the primary loop system of a nuclear power plant varies depending on its operating state. This pressure difference is mitigated by monitoring the pressure P at the inlet of valve chamber 24 of the primary loop pressure relief valve assembly. rcs And according to P rcs With P 0main P acc The comparison results are used to adjust the state of the primary loop depressurization valve group of the nuclear power plant. The state of the first two-position three-way valve 3 and the second two-position three-way valve 4 can be flexibly adjusted according to the different working states of the primary loop system of the nuclear power plant, so that the primary loop depressurization valve group of the nuclear power plant can maintain normal isolation function under different working states of the nuclear power plant.

[0138] Example 4:

[0139] This invention also provides a depressurization method for a primary loop system of a nuclear power plant, wherein the primary loop system of the nuclear power plant adopts the primary loop system of the nuclear power plant in Embodiment 2 above, and the method includes S10-S20.

[0140] S10. Monitor the pressure P at the inlet of the valve chamber (24) of the primary loop depressurization valve group in the nuclear power plant. rcs .

[0141] S20, P rcs With P 0main P accThe comparison results are obtained, and corresponding valve status adjustment suggestions are given based on the comparison results. The operator switches the primary loop depressurization valve group of the nuclear power plant to the first open state or the second open state according to the valve status adjustment suggestions.

[0142] Step S20 includes: when the comparison result is P 0main >P rcs In the event of a third valve status adjustment suggestion, the operator controls the first two-position three-way valve 3 to switch to the first state, and controls the second two-position three-way valve 4 to switch to the fourth state, so that the nuclear power plant primary loop pressure relief valve group is in the first open state; or, in P rcs Under any circumstances, a fourth valve status adjustment suggestion is given. The operator controls the second two-position three-way valve 4 to switch to the third state according to the fourth valve status adjustment suggestion, so that the nuclear power plant primary loop depressurization valve group is in the second open state.

[0143] For example, the first opening state is the automatic opening state under low pressure, and the second opening state is the state that can be manually opened in any state.

[0144] The comparison result is P. 0main >P rcs In cases such as an accident, the next circuit pressure drops from 15.5 MPa to a level lower than the opening pressure P of main valve 2. 0main At this time, main valve 2 can be opened automatically to depressurize the primary loop system of the nuclear power plant.

[0145] In P rcs Under any circumstances, that is, the next loop can be in any state, the primary loop depressurization valve group of the nuclear power plant can be put in the second open state, that is, kept open, in order to depressurize the primary loop system of the nuclear power plant.

[0146] Therefore, the state of the depressurization valve group of the nuclear power plant's primary loop can be flexibly adjusted according to different operating states of the primary loop, so that the primary loop of the nuclear power plant can achieve depressurization under different operating states.

[0147] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A primary loop pressure relief valve assembly for a nuclear power plant, characterized in that, Includes a main valve (2), a first two-position three-way valve (3), and a second two-position three-way valve (4); The main valve (2) includes a main valve body (1) and a valve core. The main valve body (1) has a sealing cavity (215) and a valve cavity (24). The valve cavity (24) is used to connect the primary coolant and the atmosphere. The power end of the valve core is located in the sealing cavity (215), and the sealing end is located in the valve cavity (24). The valve core can slide in the main valve body (1) under the pressure of the medium in the sealing cavity (215) to open or close the opening of the valve cavity (24). The first two-position three-way valve (3) has a first input port (311), a second input port (312), and a first output port (313). The first input port (311) is connected to the primary circuit coolant, and the second input port (312) is connected to the constant pressure source. The first two-position three-way valve (3) has a first state and a second state; in the first state, the first input port (311) is connected to the first output port (313); in the second state, the second input port (312) is connected to the first output port (313); The second two-position three-way valve (4) has a third input port (411), a fourth input port (412), and a second output port (413). The third input port (411) is connected to an atmospheric pressure source, the fourth input port (412) is connected to the first output port (313), and the second output port (413) is connected to the sealing cavity (215). The second two-position three-way valve (4) has a third state and a fourth state. In the third state, the third input port (411) is connected to the second output port (413). In the fourth state, the fourth input port (412) is connected to the second output port (413). The first two-position three-way valve (3) can be switched between a first state and a second state, and the second two-position three-way valve (4) can be switched between the third state and the fourth state to change the medium and pressure intensity into the sealed cavity (215), and the medium into the sealed cavity (215) opens the pressure intensity setting value P of the valve cavity (24) 0main Satisfies: P0﹤P 0main ﹤P acc , wherein P0 is the atmospheric pressure, and P acc is the pressure intensity of the constant pressure source.

2. The nuclear power plant primary loop pressure relief valve assembly according to claim 1, characterized in that, The first two-position three-way valve (3) includes a first valve body (30), a first control piston assembly, and a first drive assembly; the first valve body (30) has a first inner cavity, and the first input port (311), the second input port (312), and the first output port (313) are all disposed on the side wall of the first valve body (30) and are all in communication with the first inner cavity; the first control piston assembly is located in the first inner cavity and forms a first communication cavity (31) with the side wall of the first valve body (30); the first drive assembly can drive the first control piston assembly to move to change the position of the first communication cavity, so that the first two-position three-way valve (3) switches between a first state and a second state; in the first state, the first input port (311) and the first output port (313) are both in communication with the first communication cavity (31); in the second state, the second input port (312) and the first output port (313) are both in communication with the first communication cavity (31); The second two-position three-way valve (4) includes a second valve body (40), a second control piston assembly, and a second drive assembly. The second valve body (40) has a second inner cavity. The third input port (411), the fourth input port (412), and the second output port (413) are all disposed on the side wall of the second valve body (40) and are all in communication with the second inner cavity. The second control piston assembly is located in the second inner cavity and forms a second communication cavity (41) with the side wall of the second valve body (40). The second drive assembly can drive the second control piston assembly to move to change the position of the second communication cavity, so that the second two-position three-way valve (4) switches between a third state and a fourth state. In the third state, the third input port (411) and the second output port (413) are both in communication with the second communication cavity (41). In the fourth state, the fourth input port (412) and the second output port (413) are both in communication with the second communication cavity (41).

3. The nuclear power plant primary loop pressure relief valve assembly according to claim 2, characterized in that, The first control piston assembly includes a first control piston rod (32) and a plurality of first control pistons (33) fixed on the first control piston rod (32). The plurality of first control pistons (33) are sequentially and sealed in the first inner cavity along the axial direction of the first control piston rod (32) to divide the first inner cavity into a first connecting cavity (31) and a first isolation cavity located on both sides of the first connecting cavity (31). The first driving assembly includes a first coil (301), a second coil (302), and a first driving block (303). The first coil (301) and the second coil (302) are arranged sequentially along the axial direction of the first control piston rod (32). The first driving block (303) is fixedly connected to the first control piston rod (32). When the first coil (301) is energized and the second coil (302) is de-energized, the first coil (301) drives the first driving block (303) to move along a first direction, and drives the first control piston rod (303). The piston rod (32) moves along the first direction to switch the first two-position three-way valve (3) to the first state, and the second input port (312) is connected to the first isolation chamber; when the second coil (302) is energized and the first coil (301) is de-energized, the second coil (302) drives the first drive block (303) to move along the second direction, and drives the first control piston rod (32) to move along the second direction to switch the first two-position three-way valve (3) to the second state, and the first input port (311) is connected to the first isolation chamber; The second control piston assembly includes a second control piston rod (42) and a plurality of second control pistons (43) fixed on the second control piston rod (42). The plurality of second control pistons (43) are sequentially and sealed in the second inner cavity along the axial direction of the second control piston rod (42) to divide the second inner cavity into a second connecting cavity (41) and a second isolation cavity located on both sides of the second connecting cavity (41). The second driving assembly includes a third coil (401), a fourth coil (402), and a second driving block (403). The third coil (401) and the fourth coil (402) are arranged sequentially along the axial direction of the second control piston rod (42), and the second driving block (403) is fixedly connected to the second control piston rod (42). When the third coil (401) is energized and the fourth coil (402) is de-energized, the third coil (401) drives the second driving block (403) to move along a third direction, thereby driving the second control piston rod (42). The piston rod (42) moves along a third direction to switch the second two-position three-way valve (4) to the third state, and the fourth input port (412) is connected to the second isolation chamber; when the fourth coil (402) is energized and the third coil (401) is de-energized, the fourth coil (402) drives the second drive block (403) to move along the fourth direction, and drives the second control piston rod (42) to move along the fourth direction, so that the second two-position three-way valve (4) switches to the fourth state, and the third input port (411) is connected to the first isolation chamber; Wherein, the first direction and the second direction are two opposite directions on the axis of the first control piston rod (32), and the third direction and the fourth direction are two opposite directions on the axis of the second control piston rod (42).

4. The nuclear power plant primary loop pressure relief valve assembly according to claim 3, characterized in that, The first two-position three-way valve (3) and the second two-position three-way valve (4) are arranged side by side. The axis of the first control piston rod (32) coincides with the axis of the second control piston rod (42), and the second end of the first control piston rod (32) is arranged opposite to the first end of the second control piston rod (42). The first coil (301), the second coil (302) and the first drive block (303) are all disposed near the first end of the first control piston rod (32), and the third coil (401), the fourth coil (402) and the second drive block (403) are all disposed near the second end of the second control piston rod (42); When the first two-position three-way valve (3) is in the first state and the second two-position three-way valve (4) is in the third state, the second end of the first control piston rod (32) abuts against the first end of the second control piston rod (42); When the first two-position three-way valve (3) is in the second state and the second two-position three-way valve (4) is in the fourth state, the second end of the first control piston rod (32) abuts against the first end of the second control piston rod (42).

5. The nuclear power plant primary loop depressurization valve assembly according to claim 3, characterized in that, The first two-position three-way valve (3) and the second two-position three-way valve (4) are set at different heights, or the first two-position three-way valve (3) and the second two-position three-way valve (4) are set at the same height but are separated from each other; The first coil (301) and the second coil (302) are respectively located at both ends of the first control piston rod (32); there are two first drive blocks (303), one of which is fixedly connected to the first end of the first control piston rod (32), and the other of which is fixedly connected to the second end of the first control piston rod (32). The third coil (401) and the fourth coil (402) are located at the two ends of the first control piston rod (32), respectively; there are two second drive blocks (403), one of which is connected to the first end of the second control piston rod (42), and the other is fixedly connected to the second end of the second control piston rod (42).

6. The nuclear power plant primary loop pressure relief valve assembly according to claim 3, characterized in that, It also includes a rotary switch (5), which includes a moving contact (501) and multiple stationary contacts; The moving contact (501) is electrically connected to the power supply, and the moving contact (501) can also be electrically connected to one of the plurality of stationary contacts; the plurality of stationary contacts are respectively electrically connected to the second coil (302), the first coil (301), the fourth coil (402) and the third coil (401).

7. The nuclear power plant primary loop pressure relief valve assembly according to claim 6, characterized in that, An empty contact is also provided between two adjacent stationary contacts.

8. The nuclear power plant primary loop pressure relief valve assembly according to claim 1, characterized in that, It also includes a control component, which includes a pressure sensor and a controller; The pressure sensor is located at the inlet of the valve chamber (24) and is used to monitor the pressure P of the cooling medium entering the valve chamber (24). rcs and outputs pressure P rcs Information pressure signals; After receiving the pressure signal, the controller and the pressure sensor will... rcs With P 0main P acc The comparison results are obtained, and corresponding valve status adjustment suggestions are given based on the comparison results; the operator controls the first two-position three-way valve (3) and the second two-position three-way valve (4) according to the valve status adjustment suggestions; The comparison result is P 0main <P rcs In the event that the main valve (2) does not need to be opened, the controller provides a first valve state adjustment suggestion. The operator switches the first two-position three-way valve (3) to the first state and switches the second two-position three-way valve (4) to the fourth state according to the first valve state adjustment suggestion, so that the nuclear power plant primary loop depressurization valve group is in the first isolation state. or, The comparison result is P rcs <P acc In cases where the main valve (2) does not need to be opened, the controller provides a second valve state adjustment suggestion. The operator, based on this suggestion, switches the first two-position three-way valve (3) to the second state and the second two-position three-way valve (4) to the fourth state, so that the nuclear power plant primary loop depressurization valve group is in the second isolation state; or... The comparison result is P 0main >P rcs In the event that the main valve (2) needs to be opened, the controller provides a third valve state adjustment suggestion. The operator switches the first two-position three-way valve (3) to the first state and switches the second two-position three-way valve (4) to the fourth state according to the third valve state adjustment suggestion, so that the nuclear power plant primary loop depressurization valve group is in the first open state. or, In P rcs In any situation, if the main valve (2) needs to be opened, the controller provides a fourth valve status adjustment suggestion. The operator switches the second two-position three-way valve (4) to the third state according to the fourth valve status adjustment suggestion, so that the nuclear power plant primary loop depressurization valve group is in the second open state.

9. The nuclear power plant primary loop pressure relief valve assembly according to claim 8, characterized in that, P acc The value range is 1MPa-5MPa.

10. The nuclear power plant primary loop pressure relief valve assembly according to any one of claims 1-9, characterized in that, The valve core includes a main piston assembly and a main spring (26). The main piston assembly includes a main piston rod, a main piston (25), and a valve disc (27). The main piston rod is slidably disposed in the main valve body (1). The main piston (25) is fixed on the main piston rod and located in the sealing cavity (215). The valve disc (27) is fixed on the main piston rod and located in the valve cavity (24). The main spring (26) is located in the sealing cavity (215) and compressed between the main piston (25) and the bottom wall of the sealing cavity (215). The medium entering the sealed cavity (215) opens the pressure set value P of the valve cavity (24). 0main Also satisfies: P 0main ×(A1-A2)+G=F, where A1 is the cross-sectional area of ​​the main piston (25), A2 is the cross-sectional area of ​​the valve disc (27), G is the weight of the main piston assembly, and F is the elastic force of the main spring (26) when the valve chamber (24) is closed.

11. A primary loop system for a nuclear power plant, characterized in that, include: The main body of the primary loop system is located inside the containment. The pressure relief pipeline is connected to the main body of the primary loop system; and, The nuclear power plant primary loop depressurization valve assembly as described in any one of claims 1-10 is installed on the depressurization pipeline.

12. An isolation method for a primary loop system of a nuclear power plant, characterized in that, The nuclear power plant primary loop system adopts the nuclear power plant primary loop system of claim 11, and the method includes: Monitor the pressure P at the inlet of valve chamber (24) of the primary loop depressurization valve assembly in the nuclear power plant. rcs ; P rcs With P 0main P acc The comparison results are obtained, and corresponding valve status adjustment suggestions are given based on the comparison results. The operator switches the nuclear power plant primary loop depressurization valve group to the first isolation state or the second isolation state according to the valve status adjustment suggestions.

13. The isolation method according to claim 12, characterized in that, The step of switching the primary loop depressurization valve group of the nuclear power plant to either the first isolation state or the second isolation state based on the comparison results includes: The comparison result is P. 0main <P rcs In the event of a situation where a first valve state adjustment suggestion is given, the operator controls the first two-position three-way valve (3) to switch to the first state according to the first valve state adjustment suggestion, and controls the second two-position three-way valve (4) to switch to the fourth state, so that the nuclear power plant primary loop depressurization valve group is in the first isolation state; or, The comparison result is P. rcs <P acc In the event of a second valve state adjustment suggestion, the operator controls the first two-position three-way valve (3) to switch to the second state according to the second valve state adjustment suggestion, and controls the second two-position three-way valve (4) to switch to the fourth state, so that the nuclear power plant primary loop depressurization valve group is in the second isolation state.

14. A method for depressurizing the primary loop system of a nuclear power plant, characterized in that, The nuclear power plant primary loop system adopts the nuclear power plant primary loop system of claim 11, and the method includes: Monitor the pressure P at the inlet of valve chamber (24) of the primary loop depressurization valve assembly in the nuclear power plant. rcs ; P rcs With P 0main P acc The comparison results are obtained, and corresponding valve status adjustment suggestions are given based on the comparison results. The operator switches the nuclear power plant primary loop depressurization valve group to the first open state or the second open state according to the valve status adjustment suggestions.

15. The depressurization method according to claim 14, characterized in that, The step of switching the primary loop depressurization valve group of the nuclear power plant to a first open state or a second open state based on the comparison result includes: The comparison result is P. 0main >P rcs In the event of a third valve status adjustment suggestion, the operator controls the first two-position three-way valve (3) to switch to the first state according to the third valve status adjustment suggestion, and controls the second two-position three-way valve (4) to switch to the fourth state, so that the nuclear power plant primary loop depressurization valve group is in the first open state; or, In P rcs Under any circumstances, a fourth valve status adjustment suggestion is given. The operator controls the second two-position three-way valve (4) to switch to the third state according to the fourth valve status adjustment suggestion, so that the nuclear power plant primary loop depressurization valve group is in the second open state.

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