Pressure relief valve and reactor coolant system

Abstract

The present application provides a kind of pressure relief valve, including high-pressure gas tank, cut-off device and valve body, the inlet and outlet are opened in the valve body, shear cap is also provided in the valve body, the shear cap is blocked between inlet and outlet, the cut-off device includes transmission assembly and tool bit, the cutting edge of tool bit is towards the side of shear cap, the transmission assembly is used to drive tool bit to move along cutting edge, the high-pressure gas tank is communicated with transmission assembly by electromagnetic valve, after electromagnetic valve triggers, for pouring high-pressure gas into transmission assembly, drive transmission assembly to move tool bit and cut off shear cap, so that inlet and outlet are communicated to realize pressure relief.The pressure relief valve of the present application has simple structure, ensures no leakage during operation and is sensitive, and the present application also provides a kind of reactor coolant system.

Description

TECHNICAL FIELD

[0001] The present application relates to a pressure relief valve and a reactor coolant system comprising the same. BACKGROUND

[0002] In a pressurized water reactor nuclear power plant, the reactor coolant system is one of the most important barriers for containing radioactive substances, and is directly related to the safety performance of the nuclear power plant. The reactor coolant system needs to be provided with various protection measures, such as a pressurizer safety valve and a severe accident pressure relief valve provided for overpressure protection of the reactor coolant system.

[0003] Currently, the pressure relief valves mainly include spring safety valves, pilot safety valves, electric or pneumatic isolation valves, and gas-liquid linkage isolation valves, which are used to open and relieve pressure when the system pressure reaches the valve body setting pressure. However, these valve bodies all have the risk of leakage, and cannot guarantee zero leakage during normal operation of the nuclear power plant.

[0004] In addition to the above-mentioned valve bodies, there is also a scheme of using a burst valve, which is used to trigger the burst unit inside the valve when receiving an opening valve signal, to connect the inlet and outlet of the valve to achieve the function of system pressure relief. However, the burst valve has a complex structure, and there is a problem that the firecracker inside the burst valve may not be triggered due to aging. SUMMARY

[0005] The present application provides a pressure relief valve, which has a simple structure, ensures zero leakage during operation, and is sensitive, and also provides a reactor coolant system.

[0006] The present application provides a pressure relief valve, which has a simple structure, ensures zero leakage during operation, and is sensitive, and also provides a reactor coolant system.

[0007] Preferably, the transmission assembly comprises a piston cylinder and a first piston, one end of the piston cylinder is provided with a gas inlet for communication with the high-pressure gas tank, the other end is fixed on the valve body, the first piston is slidably arranged in the piston cylinder, the cutter head is arranged in the piston cylinder, the side of the first piston away from the gas inlet is connected with the cutter head, and the high-pressure gas tank drives the first piston to move the cutter head by filling gas into the piston cylinder.

[0008] Preferably, the transmission assembly further comprises a second piston slidingly arranged in the piston cylinder and located on the side of the first piston facing the air inlet, the area between the second piston and the air inlet serving as the air inlet zone of the piston cylinder, and the area between the second piston and the first piston serving as the sealing zone of the piston cylinder, and the sealing zone contains hydraulic oil.

[0009] Preferably, the interior of the piston cylinder is in the shape of a stepped hole, the large-diameter hole section of the stepped hole is connected to the shell of the valve body, the first piston is slidingly arranged in the large-diameter hole section, the second piston is slidingly arranged in the small-diameter hole section, and a limiting piece is arranged between the large-diameter hole section and the small-diameter hole section to make the caliber of the communication port therebetween smaller than the diameter of the small-diameter hole section, thereby limiting the second piston.

[0010] Preferably, the cutter head is in the shape of a sheet, and a through hole is formed in the cutter head, which is used to guide the inlet and outlet after the cutting cover is cut off.

[0011] Preferably, the valve body comprises a shell and a cylindrical structure, the outlet is arranged on the shell of the valve body, and the inlet is arranged on the cylindrical structure, the cutting cover is integrally formed at the end of the cylindrical structure, the shell of the valve body is sleeved outside the cylindrical structure, and a slot is formed in the shell at a position corresponding to the cutter head to allow the cutter head to enter to cut off the cutting cover.

[0012] Preferably, a groove is formed in the circumferential direction of the cutting cover.

[0013] Preferably, a concave storage area is arranged in the shell, the storage area is located at a position corresponding to the cutting cover, and is used to accommodate the cutting cover after being cut off, and a valve position sensor is arranged at the bottom of the storage area to determine the valve position of the pressure relief valve according to the position of the cutting cover.

[0014] Preferably, a check valve and an electromagnetic valve are arranged on the communication pipeline between the high-pressure gas tank and the transmission assembly, the electromagnetic valve is used to make the communication pipeline conductive after being triggered, and the check valve is used to make the high-pressure gas in the communication pipeline flow in one direction.

[0015] The application also provides a reactor coolant system comprising the pressure relief valve, the pressure relief valve is arranged in the hot pipe section of the reactor coolant system, the inlet of the valve body of the pressure relief valve is connected to the branch of the hot pipe section of the reactor coolant system, and the outlet is connected to the discharge tank of the reactor coolant system, thereby relieving the medium to be relieved in the reactor coolant system.

[0016] The pressure relief valve provided by the application is characterized in that the inlet and the outlet of the valve body are directly blocked by the shear cover, and the inlet and the outlet can be connected only after the cutter head is cut off, so that the valve body does not have movable opening blocking pieces, and there is no leakage gap, so that the valve body does not have a risk of leakage when used in a nuclear power plant. The valve body is driven by high-pressure gas in a high-pressure gas tank, so that the valve body has a simpler structure, no gunpowder aging, and the high-pressure gas can drive the cutter head at any time, and the valve body has better flexibility and can ensure triggering effectiveness. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural schematic diagram of the pressure relief valve of the embodiment 1 of the application;

[0018] Figure 2 is a structural schematic diagram of the cutter head in the pressure relief valve of the embodiment 1 of the application.

[0019] In the figure: 1, high-pressure gas tank; 11, electromagnetic valve; 12, check valve; 2, cutting device; 21, transmission assembly; 211, piston cylinder; 2111, air inlet; 2112, air inlet area; 2113, sealing area; 212, first piston; 213, second piston; 214, limiting piece; 215, shock-absorbing piece; 22, cutter head; 221, through hole; 3, valve body; 31, inlet; 32, outlet; 33, shear cover; 331, groove; 34, valve position sensor; 35, storage area; 36, shell; 37, cylindrical structure. DETAILED DESCRIPTION

[0020] The technical solutions in the application will be described clearly and completely below with reference to the drawings in the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work are within the scope of the application.

[0021] In the description of the application, it should be noted that the terms "upper", "lower", and the like indicate the orientation or positional relationship shown in the drawings, and are only used for convenience and simplification of description, and do not indicate or imply that the devices or elements referred to must be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0022] In the description of the application, the terms "first", "second", "third" are only used for description purposes, and cannot be understood as indicating or implying relative importance.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection," "setting," "installation," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] Example 1

[0025] like Figure 1 As shown, the pressure relief valve in this embodiment includes a high-pressure gas tank 1, a cutting device 2, and a valve body 3. The valve body 3 has an inlet 31 and an outlet 32. A shear cover 33 is also provided inside the valve body 3, which seals the space between the inlet 31 and the outlet 32. The cutting device 2 includes a transmission assembly 21 and a cutting head 22. The transmission assembly 21 is located on one side of the valve body 3. The cutting edge of the cutting head 22 faces the side of the shear cover 33. The transmission assembly 21 is connected to the cutting head 22 and is used to drive the cutting head 22 to move along the direction of the cutting edge. The high-pressure gas tank 1 is connected to the transmission assembly 21 and is used to inject high-pressure gas into the transmission assembly 21 to drive the transmission assembly 21 to move the cutting head 22 to cut off the shear cover 33, so that the inlet 31 and the outlet 32 ​​are connected to achieve pressure relief.

[0026] In this embodiment, the inlet 31 and outlet 32 ​​of the valve body 3 are directly sealed by the shear cap 33. Only after the shear head 22 cuts through the seal can the inlet 31 and outlet 32 ​​be connected for pressure relief. Therefore, compared to current spring-loaded safety valves and pilot-operated safety valves, this valve does not have a movable baffle, thus eliminating any potential leakage gaps. Therefore, it poses no risk of leakage when used in nuclear power plants. Furthermore, the valve body 3 is driven by high-pressure gas from the high-pressure gas tank 1. Compared to rupture valves, this design is not only simpler but also eliminates the risk of propellant aging. The high-pressure gas can drive the shear head 22 at any time, requiring no electricity. Therefore, it offers high reliability, better safety, excellent flexibility, a simple structure, high industrial maturity, and good economic efficiency.

[0027] In this embodiment, a check valve 12 and a solenoid valve 11 are provided on the connecting pipeline between the high-pressure gas tank 1 and the transmission assembly 21. The solenoid valve 11 is used to open the connecting pipeline when triggered, and the check valve 12 is used to ensure that the high-pressure gas in the connecting pipeline flows in one direction, preventing the high-pressure gas from flowing back to the high-pressure gas tank 1. The high-pressure gas can be conventional high-pressure air or high-pressure nitrogen, etc., and its pressure range is manually selected according to the volume of the valve body 3, the material of the shear cover 33, and the mass of the cutter head 22, so as to be able to push the cutter head 22 to cut off the shear cover 33. This will not be elaborated here.

[0028] The electromagnetic valve 11 can receive an external control signal, and be triggered by the control signal to make the communication pipeline between the high-pressure gas tank 1 and the transmission assembly 21 conductive. In the reactor coolant system, the medium pressure can be detected by a pressure sensing device, and then the pressure information is obtained by an external device such as a controller, and whether the signal is sent to the electromagnetic valve 11 is determined according to whether the pressure information reaches the predetermined pressure relief pressure. When the pressure relief pressure is reached, a signal can be sent to trigger the electromagnetic valve 11, so that high-pressure gas can flow into the transmission assembly 21. The pressure sensing device and the controller and the like are relatively common devices on the market, and their structures and principles are not described in detail here, and their arrangement positions and connection modes can be adaptively selected according to the layout needs.

[0029] During normal operation of the nuclear power plant, the upstream of the pressure relief valve, i.e. the inlet 31, is directly connected with the reactor coolant system, and bears the pressure and temperature of the reactor coolant system, and the downstream, i.e. the outlet 32, is at normal pressure.

[0030] In the embodiment, the transmission assembly 21 includes a piston cylinder 211 and a first piston 212. The piston cylinder 211 is provided with an air inlet 2111 at one end, which is used to communicate with the high-pressure gas tank 1, and is fixed to the valve body 3 at the other end. The first piston 212 is slidingly arranged in the piston cylinder 211, and the tool bit 22 is arranged in the piston cylinder 211. The first piston 212 is connected to the tool bit 22 at the side away from the air inlet 2111. The high-pressure gas tank 1 drives the first piston 212 to move by pouring gas into the piston cylinder 211 to drive the tool bit 22 to move. The internal structure of the transmission assembly 21 is extremely simple, so the driving is simple, and the problem of driving failure due to complex internal structure is avoided.

[0031] In the embodiment, the transmission assembly 21 further includes a second piston 213. The second piston 213 is slidingly arranged in the piston cylinder 211 and located at the side of the first piston 212 away from the air inlet 2111. The area between the second piston 213 and the air inlet 2111 is used as the air inlet area 2112 of the piston cylinder 211. The area between the second piston 213 and the first piston 212 is used as the sealing area 2113 of the piston cylinder 211. The sealing area 2113 contains hydraulic oil. The inside of the piston cylinder 211 is in the shape of a stepped hole. The large-diameter hole section of the stepped hole is connected to the shell of the valve body 3. The first piston 212 is slidingly arranged in the large-diameter hole section. The second piston 213 is slidingly arranged in the small-diameter hole section.

[0032] That is, the transmission assembly 21 of the embodiment is provided with the sealing area 2113 containing hydraulic oil. According to Pascal's law, the force acting on the second piston 213 is transmitted to the first piston 212. Not only the amplification of the force is realized, but also the force of the high-pressure gas is converted into more uniform and stable driving force. Moreover, the setting mode effectively reduces the force required for shearing.

[0033] A limiting part 214 is arranged between the large-diameter hole section and the small-diameter hole section, and is used to make the communication aperture between the two smaller than the diameter of the small-diameter hole section, so as to limit the second piston 213, and avoid the second piston 213 falling into the large-diameter hole section and causing the transmission assembly 21 to fail. The limiting part 214 can be made of rubber.

[0034] In this embodiment, a damping sheet 215 is arranged on the shell area of the valve body 3 covered by the piston cylinder 211, and is used to buffer the impact of the first piston 212, and prevent the first piston 212 from colliding with the valve body 3 when moving to the bottom end. The damping sheet 215 can be made of flexible materials such as rubber.

[0035] In this embodiment, as shown in Figure 2 The cutter head 22 is in a sheet shape, is generally made of high-carbon alloy steel, and is in a rectangular sheet structure. The area is accurate to cover the whole shear cover 33, so as to ensure that the shear cover 33 can be completely cut off. The cutting edge is located on the bottom edge of the cutter head 22. A through hole 221 is arranged on the cutter head 22. After the cutter head 22 cuts off the shear cover 33, the cutter head 22 is arranged between the inlet 31 and the outlet 32, so that the through hole 221 is aligned with the flow channel in the valve 3 after the cutter head 22 cuts off the shear cover 33, and is used to guide the inlet 31 and the outlet 32.

[0036] In this embodiment, the valve body 3 includes an outer shell 36 made of alloy material and a cylindrical structure 37. The outlet 32 is arranged on the outer shell 36 of the valve body 3, the inlet 31 is arranged on the cylindrical structure 37, and the shear cover 33 is integrally formed at the end of the cylindrical structure 37. Therefore, the manufacturing and processing are very simple, and the inlet 31 is less likely to leak medium. The inner hole of the cylindrical structure 37 has a tapered hole section between the inlet 31 and the shear cover 33. The tapered hole section plays a transition role. The large-diameter section can connect the original pipeline of the medium to be depressurized, the small-diameter section makes the shear cover 33 smaller, controls the volume of the whole valve, and is more convenient to install. In addition, the cutter head 22 is smaller and more flexible to drive.

[0037] The outer shell 36 of the valve body 3 is sleeved outside the cylindrical structure 37. A slot is arranged on the outer shell 36 at a position corresponding to the cutter head 22, so as to allow the cutter head 22 to enter the inside of the valve body 3, thereby achieving the cutting of the shear cover 33.

[0038] In this embodiment, a groove 331 is arranged around the shear cover 33. The groove 331 is arranged at a position corresponding to the cutting edge of the cutter head 22, so that the wall thickness of the shear cover 33 is thinner and the shear cover 33 is easier to be cut off.

[0039] In this embodiment, a recessed storage area 35 is arranged in the outer shell 36. The storage area 35 is arranged at a position corresponding to the shear cover 33 below, and is used to accommodate the cut-off shear cover 33. After the cutter head 22 cuts off the shear cover 33, the shear cover 33 falls into the storage area 35, so as to avoid affecting the flow of the medium.

[0040] The bottom of the storage area 35 is provided with a valve position sensor 34 for determining the valve position of the pressure relief valve according to the position of the shearing cover 33, i.e. when the shearing cover 33 is not sheared, the position of the shearing cover 33 is always unchanged, when the position of the shearing cover 33 is changed, it means that the shearing cover 33 is sheared and the pressure relief valve is in the pressure relief valve position, so it can be used to determine whether the valve body 3 is opened. The setting position of the valve sensor 34 not only can conveniently receive the position of the shearing cover 33, but also can conveniently make wiring, and the valve position output can be obtained. The valve position sensor 34 can be a conventional distance sensor on the market.

[0041] Embodiment 2

[0042] The reactor coolant system of the embodiment includes the pressure relief valve in embodiment 1, the pressure relief valve is arranged in the hot leg of the reactor coolant system, the inlet 31 of the valve body 3 is communicated on the branch of the hot leg of the reactor coolant system, and the outlet 32 is communicated with the discharge tank of the reactor coolant system, and is used for relieving the medium to be relieved in the reactor coolant system. The pressure relief process of the reactor coolant system is more sensitive, has higher reliability and better safety.

[0043] It can be understood that the above embodiments are only exemplary embodiments for illustrating the principles of the present application, and the present application is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and essence of the present application, and these modifications and improvements are also considered to be within the protection scope of the present application.

Claims

1. A pressure relief valve, characterized by: The utility model relates to a high-pressure gas tank (1), a cutting device (2) and a valve body (3), The valve body (3) is provided with an inlet (31) and an outlet (32), and a shearing cover (33) is further arranged in the valve body (3), the shearing cover (33) is sealed between the inlet (31) and the outlet (32), The cutting device (2) comprises a transmission assembly (21) and a cutter head (22), the transmission assembly (21) is arranged on one side of the valve body (3), the cutting edge of the cutter head (22) faces the side of the shearing cover (33), the transmission assembly (21) is connected with the cutter head (22) and is used for driving the cutter head (22) to move along the cutting edge, The high-pressure gas tank (1) is communicated with the transmission assembly (21) and is used for filling high-pressure gas into the transmission assembly (21) to drive the transmission assembly (21) to drive the cutter head (22) to move and cut off the shearing cover (33), so that the inlet (31) and the outlet (32) are communicated to realize pressure relief. The transmission assembly (21) comprises a piston cylinder (211) and a first piston (212), One end of the piston cylinder (211) is provided with an air inlet (2111) and is communicated with the high-pressure gas tank (1), the other end is fixed on the valve body (3), and the first piston (212) is slidably arranged in the piston cylinder (211), The cutter head (22) is arranged in the piston cylinder (211), one side of the first piston (212) away from the air inlet (2111) is connected with the cutter head (22), and the high-pressure gas tank (1) drives the first piston (212) to drive the cutter head (22) to move by filling gas into the piston cylinder (211); The transmission assembly (21) further comprises a second piston (213), the second piston (213) is slidably arranged in the piston cylinder (211) and located on one side of the first piston (212) away from the air inlet (2111), The area between the second piston (213) and the air inlet (2111) is used as an air inlet area (2112) of the piston cylinder (211), the area between the second piston (213) and the first piston (212) is used as a sealing area (2113) of the piston cylinder (211), and hydraulic oil is arranged in the sealing area (2113).

2. The pressure relief valve of claim 1, wherein: The inside of the piston cylinder (211) is in the shape of a stepped hole, a large-diameter hole section in the stepped hole is connected with the shell of the valve body (3), the first piston (212) is slidably arranged in the large-diameter hole section, and the second piston (213) is slidably arranged in a small-diameter hole section, And a limiting piece (214) is arranged between the large-diameter hole section and the small-diameter hole section, so that the caliber of the communication port between the large-diameter hole section and the small-diameter hole section is smaller than the diameter of the small-diameter hole section, and the second piston (213) is limited.

3. The pressure relief valve of claim 1, wherein: The cutter head (22) is in the shape of a sheet, the cutter head (22) is provided with a through hole (221), and the through hole (221) is used for guiding the inlet (31) and the outlet (32) after the cutter head (22) cuts off the shearing cover (33).

4. The pressure relief valve of claim 1, wherein: The valve body (3) comprises a shell (36) and a cylindrical structure (37), the outlet (32) is arranged on the shell (36) of the valve body (3), the inlet (31) is arranged on the cylindrical structure (37), and the shearing cover (33) is integrally formed at the end of the cylindrical structure (37), The outer shell (36) of the valve body (3) is sleeved outside the cylindrical structure (37), and the outer shell (36) is slotted at a position corresponding to the cutter head (22), so that the cutter head (22) can enter to cut off the shear cover (33).

5. The pressure relief valve of claim 4, wherein: The shear cover (33) is circumferentially provided with a groove (331).

6. The pressure relief valve of claim 4, wherein: The outer shell (36) is internally provided with a concave storage area (35) located at a position corresponding to the shear cover (33) below, for accommodating the cut-off shear cover (33), The bottom of the storage area (35) is provided with a valve position sensor (34) for determining the valve position of the pressure relief valve according to the position of the shear cover (33).

7. The pressure relief valve of claim 1, wherein: The communication pipeline between the high-pressure gas tank (1) and the transmission assembly (21) is provided with a check valve (12) and an electromagnetic valve (11), The electromagnetic valve (11) is used to make the communication pipeline conductive after being triggered, and the check valve (12) is used to make the high-pressure gas in the communication pipeline flow unidirectionally.

8. A reactor coolant system characterized by: The pressure relief valve according to any one of claims 1 to 7 is arranged in a hot leg section of a reactor coolant system, an inlet (31) of a valve body (3) of the pressure relief valve is communicated on a branch of the hot leg section of the reactor coolant system, and an outlet (32) is communicated with a discharge tank of the reactor coolant system, so as to relieve pressure of a medium to be relieved in the reactor coolant system.

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