CN116085502A

CN116085502A - Valve group for pressure relief and discharge of primary circuit

Info

Publication number: CN116085502A
Application number: CN202310100583.4A
Authority: CN
Inventors: 石雪垚; 荆春宁; 王辉; 陈巧艳; 杨长江; 王广飞; 吴宇翔
Original assignee: China Nuclear Power Engineering Co Ltd
Current assignee: China Nuclear Power Engineering Co Ltd
Priority date: 2023-01-28
Filing date: 2023-01-28
Publication date: 2023-05-09

Abstract

The invention provides a valve group for pressure relief and discharge of a primary circuit, comprising: the main valve is provided with a sealing cavity and a valve cavity communicated with a loop coolant and the atmosphere, the pilot valve is provided with a first sealing cavity, a first channel, a second channel and a second sealing cavity which are sequentially arranged, the outlets of the first channel and the second channel are communicated with the sealing cavity of the main valve, the outlets of the first control valve and the second control valve are respectively communicated with the sealing cavity of the first channel and the sealing cavity of the second channel, and the first control valve and the second control valve are combined by on-off to control medium entering the sealing cavity of the first channel and the second channel so as to control the valve core of the pilot valve to slide to open or close the first channel and the second channel, and further control medium entering the sealing cavity of the main valve so as to control the valve core of the main valve to slide to open or close the main valve cavity. The invention can realize the automatic opening of the main valve without external energy input and always maintain the opening state under the condition that one loop is satisfied, and can realize the manual opening of the main valve and ensure the effective isolation of the main valve during the shutdown and the refueling.

Description

Valve group for pressure relief and discharge of primary circuit

Technical Field

The invention relates to the technical field of nuclear power safety, in particular to a valve group for pressure relief and discharge of a primary loop.

Background

In pressurized water reactor nuclear power plants, the reactor coolant system is one of the most important barriers for containment of radioactive materials, directly related to the safety performance of the plant.

The reactor coolant system of a nuclear power plant has high pressure during normal operation, and an overpressure protection valve and a loop pressure relief valve are required to be arranged on the reactor coolant system in order to ensure that the system is not overpressurized after an accident and the reactor core is continuously cooled after the accident.

Currently available overpressure protection valves and pressure relief valves mainly include the following:

(1) The spring type safety valve is used for automatically opening and relieving pressure when the system pressure reaches the setting pressure of the safety valve, and the overpressure protection of the prior art system is most widely applied. The safety valve is characterized in that the safety valve can only perform an overpressure protection function, and the safety valve can not be opened manually when the pressure is lower than the opening pressure.

(2) The pilot operated safety valve is similar to a spring type safety valve, and is capable of automatically opening and releasing pressure when the system pressure reaches the setting pressure of the safety valve, so that compared with the spring type safety valve, the pilot operated safety valve is higher in reliability and is mainly applied to a pressure stabilizer safety valve at present. This type of safety valve requires less power when opened, and has disadvantages in that it is required to maintain the energized state all the time when manual opening is required, and the open state cannot be maintained at low pressure.

(3) And when the system pressure reaches a design requirement fixed value, the electric or pneumatic isolating valve is controlled to be opened or closed by a power supply. This type of valve is characterized in that it can be opened at any time and is maintained in its original state after losing its power supply, and has the disadvantage of requiring a large power (electric power or pneumatic power) when being opened.

(4) The explosion valve is used for opening a valve signal to trigger an explosion unit in the valve, high-pressure gas is generated to push a piston in the valve to move, and a shearing cover of the valve diameter can be cut off in impact movement, so that a valve inlet and a valve outlet are connected, and the safety function of pressure relief of a system is realized. This type of valve is characterized by an always open state, once opened, which cannot be restored.

Disclosure of Invention

The invention aims to solve the technical problems in the prior art, and provides a valve group for pressure relief and discharge of a primary valve, which can realize automatic opening of the primary valve without external energy input and always maintain an open state under the condition that the primary valve meets the primary loop, and can realize manual opening of the primary valve and ensure effective isolation of the primary valve during normal operation and shutdown and refueling.

The technical scheme adopted for solving the technical problems of the invention is as follows:

The invention provides a valve group for pressure relief and discharge of a primary circuit, comprising: a main valve and a control valve assembly, the main valve comprising: the main valve body is provided with a main sealing cavity and a main valve cavity, the main valve cavity is used for communicating a loop coolant with the atmosphere, one end of the main valve core is positioned in the main sealing cavity, the other end of the main valve core is positioned in the main valve cavity, the main valve core can slide in the main valve body under the pressure of medium entering the main sealing cavity so as to open or close the main valve cavity,

the control valve assembly includes a pilot valve and first and second control valves,

the pilot valve comprises a pilot valve body and a pilot valve core, wherein the pilot valve body is provided with a first sealing cavity, a first channel, a second channel and a second sealing cavity which are sequentially distributed, the pilot valve core comprises a driving structure and a valve core structure, one end of the driving structure is positioned in the first sealing cavity, the other end of the driving structure is positioned in the second sealing cavity, the valve core structure is connected with the driving structure, one end of the valve core structure is positioned in the first channel, the other end of the valve core structure is positioned in the second channel, the driving structure can slide in the pilot valve body under the action of the pressure difference of medium entering the first sealing cavity and medium entering the second sealing cavity so as to drive the valve core structure to open the first channel and close the second channel or close the first channel and open the second channel, the outlets of the first channel and the second channel are communicated with the main sealing cavity,

The first control valve is provided with a first input port, a second input port and a first output port, the first output port is communicated with the first sealing cavity, the first input port is communicated with a loop volume control box or a pressure relief box, the second input port is communicated with a constant pressure source,

the second control valve is provided with a third input port, a fourth input port and a second output port, the second output port is respectively communicated with the inlet of the first channel and the second sealing cavity, the third input port is communicated with a constant pressure source, the fourth input port is communicated with a loop coolant,

when the first control valve is electrified, the first output port of the first control valve is communicated with the first input port and is disconnected with the second input port, when the first control valve is de-electrified, the first output port of the first control valve is communicated with the second input port and is disconnected with the first input port,

when the second control valve is electrified, the second output port is communicated with the third input port and is disconnected with the fourth input port, when the second control valve is de-electrified, the second output port is communicated with the fourth input port and is disconnected with the third input port,

setting value P of pressure of medium in main sealing cavity for opening main valve _0main The method meets the following conditions: p0 < P _0main And Pacc, where P0 is atmospheric pressure, pacc is the pressure of the constant pressure source,

The medium entering the second sealing cavity opens the pressure setting value P of the pilot valve _0twin The method meets the following conditions: pacc×A ₁ ＝P _0twin ×A ₂ Wherein Pacc is the pressure of the constant pressure source, A ₁ Is the cross-sectional area of the first pilot piston, A ₂ Is the cross-sectional area of the second pilot piston, A ₂ ＜A ₁ 。

Optionally, the first control valve comprises a first control valve body, a first control piston assembly and a first solenoid valve,

the first control valve body is provided with a first main cavity and a first side cavity, the first control piston assembly is arranged in the first main cavity, the first electromagnetic valve is arranged in the first side cavity, the first input port, the second input port and the first output port are all arranged on the first control valve body and are all communicated with the first main cavity, the first control piston assembly comprises a first control piston rod and a plurality of first control pistons fixed on the first control piston rod, the plurality of first control pistons are sequentially and hermetically arranged in the first main cavity along the axial direction of the first control piston rod in a sliding manner so as to divide the first main cavity into a plurality of first sub-cavities, one end of the first control piston rod extends out of the first main cavity and is connected with the first electromagnetic valve,

the first output port is positioned at one side of the radial direction of the first control piston rod, the first input port and the second input port are positioned at the other side of the radial direction of the first control piston rod, when the first electromagnetic valve is electrified, the first input port and the second input port can drive the first control piston assembly to move axially until the first output port is communicated with the first input port only through one of the first subchambers, meanwhile, the second input port is positioned in the adjacent other first subchamber, so that the first control valve is in a first electrified state, and when the first electromagnetic valve is in a power failure state, the first input port and the second input port can drive the first control piston assembly to move reversely axially until the first output port is communicated with the second input port only through one of the first subchambers, and meanwhile, the first input port is positioned in the adjacent other first subchamber, so that the first control valve is in a first power failure state;

The second control valve comprises a second control valve body, a second control piston assembly and a second electromagnetic valve,

the second control valve body is provided with a second main cavity and a second side cavity, the second control piston assembly is arranged in the second main cavity, the second electromagnetic valve is arranged in the second side cavity, the third input port, the fourth input port and the second output port are all arranged on the second control valve body and are all communicated with the second main cavity, the second control piston assembly comprises a second control piston rod and a plurality of second control pistons fixed on the second control piston rod, the plurality of second control pistons are sequentially and hermetically arranged in the second main cavity along the axial direction of the second control piston rod so as to divide the second main cavity into a plurality of second sub-cavities, one end of the second control piston rod extends out of the second main cavity and is connected with the second electromagnetic valve,

the second output port is located one side of the radial direction of the second control piston rod, the third input port and the fourth input port are both located the other side of the radial direction of the second control piston rod, when the second electromagnetic valve is powered on, the second control piston assembly can be driven to move axially until the second output port is communicated with the third input port only through one of the second subchambers, meanwhile, the fourth input port is located in the adjacent second subchamber, so that the second control valve is located in a second power-on state, when the second electromagnetic valve is powered off, the second control piston assembly can move axially reversely until the second output port is communicated with the fourth input port only through one of the second subchambers, and meanwhile, the third input port is located in the adjacent second subchamber, so that the second control valve is located in a second power-off state.

Optionally, the first electromagnetic valve comprises a first sucker, a first coil and a first return spring, the first coil is fixed on the outer end wall of the first main chamber, the first sucker is fixed on one end of the first control piston rod extending into the first side chamber, the first return spring is connected between the cavity wall of the first side chamber and the first sucker,

when the first electromagnetic valve is powered on, the first sucker moves towards the first coil to be fixedly connected with the first coil so as to drive the first control piston assembly to axially move to a state that the first control valve is in a first power-on state, the first reset spring is lengthened, and when the first electromagnetic valve is powered off, the first sucker is disconnected with the first coil and the first reset spring is reset so as to drive the first control piston assembly to axially move to a state that the first control valve is in a first power-off state;

the second electromagnetic valve comprises a second sucker, a second coil and a second reset spring, the second coil is fixed on the outer end wall of the second main chamber, the second sucker is fixed on one end of the second control piston rod extending into the second side chamber, the second reset spring is connected between the chamber wall of the second side chamber and the second sucker,

when the second electromagnetic valve is powered on, the second sucker moves towards the second coil to be fixedly connected with the second coil so as to drive the second control piston assembly to axially move to the state that the second control valve is in the second power-on state, the second reset spring is lengthened, and when the second electromagnetic valve is powered off, the second sucker is disconnected with the second coil and the second reset spring is reset so as to drive the second control piston assembly to axially move to the state that the second control valve is in the second power-off state.

Optionally, the control valve assembly is provided with a plurality of sets, and the first channel outlet and the second channel outlet of the plurality of sets of control valve assemblies are communicated with the main sealing cavity of the main valve.

The first electromagnetic valves of the first control valves are provided with a plurality of first suckers of the first electromagnetic valves are fixedly connected with the first control piston rod,

the second electromagnetic valves of the second control valves are provided with a plurality of second suckers, and the second suckers of the second electromagnetic valves are fixedly connected with the second control piston rod.

The main valve core comprises a main piston assembly and a main spring, the main piston assembly comprises a main piston rod, a main piston and a valve disc, the main piston rod is slidably arranged in the main valve body, the main piston is fixed on the main piston rod and is positioned in a main sealing cavity, the valve disc is fixed on the main piston rod and is positioned in a main valve cavity, and the main spring is positioned in the main sealing cavity and is compressed between the main piston and the bottom wall of the main valve cavity.

Optionally, the main valve cavity is located at the lower part of the main sealing cavity, the main valve body is provided with a valve inlet and a valve outlet which are respectively communicated with the main valve cavity, the valve inlet is formed at the bottom of the main valve body and is used for being communicated with a loop coolant, the valve outlet is formed at the side surface of the main valve body and is used for being communicated with the atmosphere, the main piston assembly is vertically and slidably arranged in the main valve body,

Setting value P of pressure of medium in main sealing cavity for opening main valve _0main The following is also satisfied: p (P) _0main X (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 spring force of the main spring when the main valve is closed.

Optionally, the outer diameter of the valve disc gradually decreases from top to bottom, so that the outer wall of the valve disc forms a first conical surface,

the valve inlet is provided with a nozzle, the upper part of the inner wall of the nozzle is provided with a second conical surface matched with the first conical surface, and when the main piston component moves downwards to be matched with the first conical surface and the second conical surface, the valve disc closes the valve inlet.

Optionally, the main valve body comprises a main valve housing, a lower valve seat and an upper valve seat which are fixedly connected in sequence from bottom to top, the inner cavity of the main valve housing forms the main valve cavity,

the top surface of lower disk seat begins to have first groove, go up the lower part of disk seat and stretch into in the first groove and link to each other with the cell wall seal in first groove, the second groove has been seted up to the bottom surface of going up the disk seat, and the cell wall in second groove encloses with the diapire in first groove and closes and form the main seal chamber.

The main piston rod comprises a working section and a positioning section, the lower end of the working section is fixedly connected with the valve disc, the upper end of the working section penetrates through the lower valve seat and then stretches into the main sealing cavity to be fixedly connected with the main piston, the main spring penetrates through the working section,

The upper part of the upper valve seat is provided with a sealed exhaust cavity, the top of the upper valve seat is provided with a valve cover for opening or closing the exhaust cavity, the lower end of the positioning section is fixedly connected with the piston, and the upper end of the positioning section penetrates through the lower part of the upper valve seat and then stretches into the exhaust cavity.

Optionally, the driving structure comprises a first pilot piston, a second pilot piston and a pilot piston rod, the pilot piston rod is axially and slidably arranged in the pilot valve body and connected between the first pilot piston and the second pilot piston, the first pilot piston is hermetically and slidably arranged in a first sealing cavity, the second pilot piston is hermetically and slidably arranged in a second sealing cavity,

the valve core structure comprises a first pilot valve, a second pilot valve and a pilot valve rod, wherein the pilot valve rod is arranged in parallel with the pilot piston rod and is connected with the pilot piston rod, the pilot valve rod is axially arranged in the pilot valve body in a sliding mode and is connected between the first pilot valve and the second pilot valve, the first pilot valve is arranged in a first channel and is used for opening or closing the first channel, and the second pilot valve is arranged in a second channel and is used for opening or closing the second channel.

Optionally, the first pilot valve comprises a first valve plate and a first valve core component, the first valve plate is fixed in the first channel and closes the first channel, a first valve hole is arranged on the first valve plate, the first valve core component is arranged in the first channel in a sliding way and matched with the first valve hole,

The second pilot valve comprises a second valve plate and a second valve core component, the second valve plate is fixed in the second channel and closes the second channel, a second valve hole is arranged on the second valve plate, the second valve core component is arranged in the second channel in a sliding way and matched with the second valve hole,

the pilot valve rod is connected to the first valve core component and the second valve core component, and drives the first valve core component to open the first valve hole and drives the second valve core component to close the second valve hole when the pilot valve rod moves axially, or drives the first valve core component to close the first valve hole and drives the second valve core component to open the second valve hole.

Optionally, the first channel comprises a first inlet section, a first pilot valve cavity and a first outlet section which are communicated in sequence, the first pilot valve is positioned in the first pilot valve cavity, the first pilot valve cavity is provided with a space for the first valve core component to slide,

the second channel comprises a second inlet section, a second pilot valve cavity and a second outlet section which are sequentially communicated, the second outlet section is communicated with the first outlet section, the second pilot valve is positioned in the second pilot valve cavity, and the second pilot valve cavity is provided with a space for the second valve core component to slide.

Optionally, the pilot piston rod is connected with the pilot valve rod through a pilot driving plate, and a groove which can be used for the pilot driving plate to axially move along the pilot piston rod is formed in the pilot valve body.

The invention combines the main valve, the pilot valve and the two control valves to form a valve group for releasing pressure and discharging a loop, wherein a main valve body of the main valve is provided with a closed cavity and a valve cavity, a valve core of the main valve is arranged in the main valve in a sliding way, and the valve core can slide in the main valve body under the pressure of medium entering the closed cavity so as to open or close the valve cavity; the pilot valve body of the pilot valve is provided with a first sealing cavity, a first channel, a second channel and a second sealing cavity which are sequentially distributed, the pilot valve core of the pilot valve is arranged in the pilot valve body in a sliding way, and the pressure of medium entering the first sealing cavity and medium entering the second sealing cavity can be controlledUnder the action of difference, the first channel is opened and the second channel is closed, or the first channel is closed and the second channel is opened, the outlets of the first channel and the second channel are communicated with the main sealing cavity, the first output port of the first control valve is communicated with the first sealing cavity, the first input port of the first control valve is communicated with a loop volume control box or a pressure relief box, the second input port of the first control valve is communicated with a constant pressure source, the second output port of the second control valve is respectively communicated with the inlet of the first channel and the second sealing cavity, the third input port of the second control valve is communicated with the constant pressure source, the fourth input port of the second control valve is communicated with a loop coolant, and the opening setting value P of the main valve _0main The method meets the following conditions: p0 < P _0main Pressure setting value P of < Pacc, pilot valve _0twin The method meets the following conditions: pacc×A ₁ ＝P _0twin ×A ₂ ，A ₂ ＜A ₁ Thereby:

when the valve group is in a standby state (both the first control valve and the second control valve are powered off), under the condition that the pressure of a loop is normal (about 15.5 MPa), the pressure of a constant pressure source is in a first sealing cavity of the pilot valve (for example, the pressure of an safety injection box is about 4-5 MPa), the pressure of the loop is in a second sealing cavity of the pilot valve, a pilot valve core moves upwards to open a first channel, so that the pressure source in a main sealing cavity entering a main valve is a loop, and the pressure source is far greater than the opening setting value P of the main valve _0main The main valve is closed, thereby realizing the isolation of the main valve when a loop is in normal operation, and the pressure drop is smaller than the pressure setting value P of the pilot valve when the loop is in fault _0twin When the pilot valve core moves downwards to open the second channel, so that the pressure source in the main sealing cavity of the main valve is a loop volume control box or pressure relief box (atmospheric pressure P0) which is smaller than the opening setting value P of the main valve _0main The main valve is automatically opened, thereby realizing the purposes of when the pressure of the primary circuit is abnormal (P _rcs <P _0twin ) The main valve is automatically opened, no energy input is needed in the opening process (because the first control valve and the second control valve are both powered off, and the main valve can be automatically opened when the pressure of a loop meets the condition);

In some cases, when the main valve is required to be opened manually, the first electromagnetic valve is powered off, the second electromagnetic valve is powered on, and at the moment, the pressure of the constant pressure source is in the first sealing cavity of the pilot valve (for example, the pressure of the safety injection box is about 4-5 MPa), and the pressure of the constant pressure source is in the second sealing cavityAlso constant pressure source pressure (such as pressure of the safety injection box is about 4-5 MPa), and the pressure setting value P of the pilot valve is opened due to the medium entering the second sealing cavity _0twin Greater than constant pressure source pressure Pacc (i.e. A ₂ ＜A ₁ ) So that the pilot valve core is in a downward pressure state, the second channel is opened, and therefore, the pressure source in the main sealing cavity of the main valve is a loop volume control box or a pressure relief box (atmospheric pressure P0) which is smaller than the opening setting value P of the main valve _0main The main valve is opened;

when the main valve is not desired to be opened during shutdown and refueling (the loop pressure needs to be reduced to normal pressure), the first electromagnetic valve is electrified, the second electromagnetic valve is powered off, at the moment, the first sealing cavity of the pilot valve is provided with a loop volume control box or a pressure relief box (atmospheric pressure P0), the second sealing cavity is provided with the loop pressure, and the loop pressure is reduced to the pressure setting value P of the pilot valve _0twin Below (while in standby state, the pressure in a loop drops to the pressure setting value P of the pilot valve _0twin When the main valve is opened), the main valve opening setting value P _0main Before, the pilot valves are in an upward moving state to open a first channel, a pressure source in a main sealing cavity of the main valve is a loop, and the main valve is in a closing state at the stage, so that high-pressure isolation of the valve group during shutdown and refueling is realized; if a circuit pressure continues to drop, the main valve will open, so that when a circuit pressure drops to the main valve opening setting value P _0main Before, the first electromagnetic valve and the second electromagnetic valve are electrified, at the moment, the pressure of a loop volume control box or a pressure relief box (atmospheric pressure P0) is arranged in a first sealing cavity of the pilot valve, the pressure of a constant pressure source (such as the pressure of an safety injection box is about 4-5 MPa) is arranged in a second sealing cavity, the pilot valve is in an upward moving state to open a first channel, the pressure source in a main sealing cavity entering the main valve is the pressure of the constant pressure source (such as the pressure of the safety injection box is about 4-5 MPa), and the pressure source is larger than a main valve opening setting value P _0main Even if the pressure of the primary circuit drops to the primary valve opening setting value P _0main And the main valves are in a closed state, so that the low-pressure isolation of the valve group during shutdown refueling is realized.

The design of the pressure relief valve group meets the pressure relief requirement of a primary loop of a follow-up Hualong model, and has the following technical advantages:

1) In the standby state, when the pressure of a loop meets the condition, the loop is automatically started, no energy input is needed, and the reliability is high.

2) After the valve is automatically opened, the valve can be always maintained in an opened state, and no power supply is needed to maintain the opened state, so that the long-term pressure relief of a loop is ensured.

3) Through different combinations of the electromagnetic valves, the valve can be reliably isolated in any state, and meanwhile, the valve can be manually opened in any state.

Drawings

FIG. 1 is a schematic structural view of an passive core cooling system;

FIG. 2 is a schematic diagram of a valve block for a circuit pressure relief vent according to embodiment 1 of the present invention;

FIG. 3 is a schematic structural view of a main valve;

fig. 4 is a schematic structural diagram of a pilot valve.

In the figure:

1. a pilot valve; 11. a first valve seat; 12. a second valve seat; 13. an intermediate valve seat;

14. a first valve plate; 15. a first pilot piston; 16. a pilot piston rod; 17. a first sealed cavity; 18. a first conduit; 19. a second valve plate; 110. a second pilot piston;

111. a pilot valve stem; 112. a second sealed cavity; 113. a second conduit; 114. an output pipe; 115. a first input tube; 116. a second input tube; 117. a first valve core assembly; 118. a second spool assembly; 119. a pilot dial; 120. a first pilot valve chamber; 121. a second pilot valve chamber; 122. slotting;

2. A main valve; 21. a main valve housing; 22. a lower valve seat; 23. an upper valve seat; 24. a main valve cavity; 25. a main piston; 26. a main spring; 27. a working section; 28. a valve disc; 29. a valve inlet; 210. a nozzle; 211. a valve outlet; 212. an exhaust chamber; 213. a positioning section; 214. a pilot conduit; 215. a main seal chamber;

3. a first control valve; 31. a first control valve body; 311. a first main chamber; 312. a first side chamber; 313. a first input port; 314. a second input port; 315. a first output port; 32. a first control piston assembly; 321. a first control piston rod; 322. a first control piston; 33. a first electromagnetic valve; 331. a first suction cup; 332. a first coil; 333. a first return spring;

4. a second control valve; 41. a second control valve body; 411. a second main chamber; 412. a second side chamber; 413. a third input port; 414. a fourth input port; 415. a second output port; 42. a second control piston assembly; 421. a second control piston rod; 422. a second control piston; 43. a second electromagnetic valve; 431. a second suction cup; 432. a second coil; 433. and a second return spring.

Detailed Description

The following description of the embodiments of the present invention will be made more apparent, and the embodiments described in detail, but not necessarily all, in connection with the accompanying drawings. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to fall within the scope of the invention.

In the description of the present invention, it should be noted that the orientation or positional relationship indicated by "upper" or the like is based on the orientation or positional relationship shown in the drawings, and is merely for convenience and simplicity of description, and is not meant to indicate or imply that the apparatus or element to be referred to must be provided with a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.

In the description of the present invention, the terms "first," "second," and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "connected," "configured," "mounted," "secured," and the like are to be construed broadly and may be either fixedly connected or detachably connected, or integrally connected, for example; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood by those skilled in the art in specific cases.

Example 1:

as shown in fig. 2, the present embodiment provides a valve block for a circuit pressure relief vent, comprising: a main valve 2 and a control valve assembly, the main valve 2 comprising: a main valve body and a main valve core, the main valve body is provided with a main sealing cavity 215 and a main valve cavity 24, the main valve cavity 24 is used for communicating a loop coolant and the atmosphere, one end of the main valve core is positioned in the main sealing cavity 215, the other end is positioned in the main valve cavity 24, the main valve core can slide in the main valve body under the pressure of medium entering the main sealing cavity 215 so as to open or close the main valve cavity 24,

The control valve assembly comprises a pilot valve 1 and a first control valve 3 and a second control valve 4,

the pilot valve 1 comprises a pilot valve body and a pilot valve core, wherein the pilot valve body is provided with a first sealing cavity 17, a first channel, a second channel and a second sealing cavity 112 which are sequentially distributed, the pilot valve core comprises a driving structure and a valve core structure, one end of the driving structure is positioned in the first sealing cavity 17, the other end of the driving structure is positioned in the second sealing cavity 112, the valve core structure is connected with the driving structure, one end of the valve core structure is positioned in the first channel, the other end of the valve core structure is positioned in the second channel, the driving structure can slide in the pilot valve body under the action of the pressure difference of media entering the first sealing cavity 17 and media entering the second sealing cavity 112 so as to drive the valve core structure to open the first channel and close the second channel or close the first channel and open the second channel, the outlets of the first channel and the second channel are communicated with the main sealing cavity 215,

the first control valve 3 has a first inlet 313, a second inlet 314 and a first outlet 315, the first outlet 315 being in communication with the first sealed chamber 17, the first inlet 313 being in communication with a circuit volume control or pressure relief tank, the second inlet 314 being in communication with a constant pressure source,

the second control valve 4 has a third inlet 413, a fourth inlet 414 and a second outlet 415, the second outlet 415 being in communication with the inlet of the first passage and the second sealed chamber 112, respectively, the third inlet 413 being in communication with a constant pressure source, the fourth inlet 414 being in communication with a circuit coolant,

The first control valve 3 has a first energized state in which the first output port 315 communicates with the first input port 313 and is disconnected from the second input port 314, and a first de-energized state in which the first output port 315 communicates with the second input port 314 and is disconnected from the first input port 313, which is switchable between the first energized state and the first de-energized state to vary the medium and its pressure entering the first sealed chamber 17,

the second control valve 4 has a second energized state in which the second output port 415 communicates with the third input port 413 and is disconnected from the fourth input port 414, and a second de-energized state in which the second output port 415 communicates with the fourth input port 414 and is disconnected from the third input port 413, which is switchable between the second energized state and the second de-energized state, to vary the medium and its pressure entering the second sealed chamber 112,

pressure setting value P of medium opening main valve 2 into main seal chamber 215 _0main The method meets the following conditions: p0 < P _0main And Pacc, where P0 is atmospheric pressure, pacc is the pressure of the constant pressure source,

pressure setting value P of medium opening pilot valve 1 entering second sealing cavity 112 _0twin The method meets the following conditions: pacc×A ₁ ＝P _0twin ×A ₂ Wherein Pacc is the pressure of the constant pressure source, A ₁ A is the cross-sectional area of the first pilot piston 15, A ₂ A is the cross-sectional area of the second pilot piston 110, A ₂ ＜A ₁ 。

Passive core cooling is one of the technical routes of third generation pressurized water reactor nuclear power technology. Taking AP1000 as an example, as shown in fig. 1, the passive core cooling system includes:

core water supplementing tank: the pressure is consistent with the pressure of a loop (15.5 MPa), and the water supplementing function of the reactor core at high pressure is carried out.

Safety injection box: about 4-5MPa, and bears the water supplementing function with the pressure below 4-5 MPa.

IRWST (gravity fed tank): the pressure is consistent with the atmospheric pressure and is as low as 0.1MPa, and the water supplementing function is realized when the pressure of the primary circuit is reduced to the normal pressure.

ADS valve (burst valve): the pressure relief function is born, the pressure of a loop is gradually reduced from 15.5 to normal pressure, the three water supplementing measures are sequentially put into the reactor, the IRWST gravity water injection is finally realized, the long-term cooling of the reactor core can be realized, and the long-term safety is ensured.

ADS1-3+ADS4 is sequentially put in order to avoid the problem caused by the excessively high pressure relief speed.

The ADS1-3 has smaller pressure relief speed and mainly bears the pressure relief function under high pressure.

The ADS4 pressure relief rate is relatively high, and in order to avoid the shock caused by the excessive pressure relief rate, it is necessary that a circuit pressure is lower than a certain threshold value before opening (about 8-9 MPa).

After ADS4 is turned on, the pressure of a loop can be quickly reduced to the pressure input by the safety injection box, and finally reduced to IRWST injection pressure.

The ADS prior art mainly adopts a burst valve and an electric valve, and the burst valve and the electric valve are used for outputting an electric signal to trigger the valve to open when the pressure of a primary circuit is detected to be reduced to a threshold value. The electric valve brings a plurality of difficulties to the design of the pressure relief system due to the large volume of the equipment, large energy required for opening and the like. The explosion valve has the advantages of good sealing performance and small opening power, but has certain difficulties in reliability data, intellectual property rights and the like.

The design concept of a non-energy safety system is adopted in the later model of Hualong, and a passive safety system is adopted to cope with design reference accidents. Under the design concept, a mature and reliable one-loop pressure relief system is needed, and the pressure of the one-loop can be effectively reduced to the gravity water injection pressure head in time. Therefore, a new valve design scheme is explored in addition to the explosion valve and the electric valve, and the function of pressure relief of a primary loop of a Hualong follow-up model and the application scene requirement are realized.

The pressure relief valve block is mainly used for replacing the function of ADS-4, namely, when the pressure of a loop is reduced to 8-9MPa, the pressure relief valve block can be automatically opened, the opening speed is required to be high, and at least electricity is not needed (the power can be supplied by a storage battery, and the reliability after the power supply is lost is increased).

The invention combines the main valve 2, the pilot valve 1 and two control valves to form a valve group for releasing pressure and discharging a loop, wherein a main valve body of the main valve 2 is provided with a closed cavity 215 and a valve cavity 24, a valve core of the valve is arranged in the main valve body in a sliding way, and the valve core can slide in the main valve body under the pressure of medium entering the closed cavity 215 so as to open or close the valve cavity 24; the pilot valve body of the pilot valve 1 is provided with a first sealing cavity 17, a first channel, a second channel and a second sealing cavity 112 which are sequentially arranged, a pilot valve core of the pilot valve 1 is slidingly arranged in the pilot valve body, the first channel can be opened and the second channel can be closed under the pressure difference of medium entering the first sealing cavity 17 and medium entering the second sealing cavity 112, or the first channel can be closed and the second channel can be opened, the outlets of the first channel and the second channel are communicated with the main sealing cavity 215, the first outlet 315 of the first control valve 3 is communicated with the first sealing cavity 17, the first inlet 313 is communicated with a loop volume control box or a pressure relief box (atmospheric pressure P0), the second inlet 314 is communicated with a constant pressure source safety injection box (about 4-5 MPa), the second outlet 415 of the second control valve 4 is respectively communicated with the inlet of the first channel and the second sealing cavity 112, the third inlet 413 is communicated with the constant pressure source safety injection box (about 4-5 MPa), the fourth inlet 414 is communicated with a loop coolant (normally 15.5MPa, a fault or a constant pressure tap is opened to P0) Value P _0main The method meets the following conditions: p0 < P _0main Below Pacc, the opening setting value P of the pilot valve _0twin The method meets the following conditions: pacc×a1=p _0twin X A2, whereby:

when the valve group is in a standby state (both the first control valve 3 and the second control valve 4 are powered off), under the condition that the pressure of a loop is normal (about 15.5 MPa), the pressure of a constant-pressure source safety injection box is set in the first sealing cavity 17 of the pilot valve 2 (about 4-5 MPa), the pressure of the loop is set in the second sealing cavity 112, the pilot valve core moves upwards to open the first channel, so that the pressure source in the main sealing cavity 215 entering the main valve 2 is a loop which is far greater than the opening setting value P of the main valve 2 _0main The main valve 2 is closed, thereby realizing the isolation of the main valve 2 when a loop is in normal operation, and the pressure drop is smaller than the pressure setting value P of the pilot valve 1 when the loop is in fault _0twin When the pilot valve core moves downwards to open the second channel, so that the pressure source in the main sealing cavity 215 of the main valve 2 is a loop volume control box or a pressure relief box (atmospheric pressure P0), which is smaller than the opening setting value P of the main valve 2 _0main The main valve 2 is automatically opened, thereby realizing the effect that when the pressure of the primary circuit is abnormal (P _rcs <P _0twin ) The automatic opening of the main valve 2, which does not require any energy input (since both the first control valve 3 and the second control valve 4 are de-energized, a circuit pressure is met for the condition main valve 2 to open automatically);

In some cases, when the main valve 2 needs to be opened manually, the first electromagnetic valve 3 is powered off, the second electromagnetic valve 4 is powered on, at this time, the pressure of the constant-pressure safe injection box is set in the first sealing cavity 17 of the pilot valve 1 (about 4-5 MPa), the pressure of the constant-pressure safe injection box is also set in the second sealing cavity 112 (about 4-5 MPa), and the pressure setting value P of the pilot valve 1 is opened due to the medium entering the second sealing cavity 112 _0twin The pressure of the safety injection box is greater than the pressure Pacc of the constant pressure source, so that the pilot valve core is in a downward pressure state, and the second channel is opened, therefore, the pressure source entering the main sealing cavity 215 of the main valve 2 is a loop volume control box or a pressure relief box (atmospheric pressure P0), and is smaller than the opening setting value P of the main valve 2 _0main The main valve 2 is opened;

when the shutdown and refueling (the pressure of a loop needs to be reduced to normal pressure) does not want the main valve 2 to be opened, the first electromagnetic valve 3 is electrified, and the second electromagnetic valve4, at this time, a loop volume control box or pressure relief box (atmospheric pressure P0) is arranged in the first sealing cavity 17 of the pilot valve 1, a loop pressure is arranged in the second sealing cavity 112, and the loop pressure is reduced to a pressure setting value P of the pilot valve 1 _0twin Below (while in standby mode, the pressure drops to the pressure setting value P of the pilot valve 1 in a circuit _0twin The main valve 2 is opened at the time), the main valve 2 opens the setting value P _0main Before, the pilot valve 1 is in an upward moving state to open a first channel, a pressure source entering the main sealing cavity 215 of the main valve 2 is a loop, and the main valve 2 is in a closing state at this stage, so that high-pressure isolation of the valve group during shutdown and refueling is realized; if a circuit pressure continues to drop, the main valve 2 will open, so that when a circuit pressure drops to the main valve 2 opening setting value P _0main Before, the first electromagnetic valve 3 and the second electromagnetic valve 4 are electrified, at this time, the first sealing cavity 17 of the pilot valve 1 is a loop volume control box or pressure relief box pressure (atmospheric pressure P0), the second sealing cavity 112 is a constant pressure source safe injection box pressure, the pilot valve 1 is in an upward moving state to open a first channel, the pressure source in the main sealing cavity 215 entering the main valve 2 is a constant pressure source safe injection box pressure, and the pressure source is greater than the opening setting value P of the main valve 2 _0main Even if the primary circuit pressure drops to the primary valve 2 opening setting P _0main The main valve 2 is in a closed state, so that the low-pressure isolation of the valve group during shutdown refueling is realized.

Further, the pressure relief valve of the present invention is shown in table 1 in combination with several overpressure protection valves and pressure relief valves commonly used in the field of nuclear power safety as mentioned in the background.

TABLE 1

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In the present embodiment, the first control valve 3 includes a first control valve body 31, a first control piston assembly 32 and a first solenoid valve 33,

The first control valve body 31 is provided with a first main chamber 311 and a first side chamber 312, the first control piston assembly 32 is arranged in the first main chamber 311, the first electromagnetic valve 33 is arranged in the first side chamber 312, the first input port 313, the second input port 314 and the first output port 315 are all arranged on the first control valve body 31 and are communicated with the first main chamber 311, the first control piston assembly 32 comprises a first control piston rod 321 and a plurality of first control pistons 322 fixed on the first control piston rod 321, the plurality of first control pistons 322 are sequentially and hermetically arranged in the first main chamber 311 along the axial direction of the first control piston rod 321 so as to divide the first main chamber 311 into a plurality of first sub-chambers, one end of the first control piston rod 321 extends out of the first main chamber 311 and is connected with the first electromagnetic valve 33,

first output port 315 is located on one side of first control piston rod 321 in the radial direction, and first input port 313 and second input port 314 are located on the other side of first control piston rod 321 in the radial direction, and when first solenoid valve 33 is energized, they can drive first control piston assembly 32 to move axially until first output port 315 is only in communication with first input port 313 through one of the first subchambers, while second input port 314 is located in the adjacent other first subchamber, so that first control valve 3 is in the first energized state, and when first solenoid valve 33 is de-energized, they can drive first control piston assembly 32 to move axially and reversely until first output port 315 is only in communication with second input port 314 through one of the first subchambers, while first input port 313 is located in the adjacent other first subchamber, so that first control valve 3 is in the first de-energized state;

The second control valve 4 includes a second control valve body 41, a second control piston assembly 42 and a second solenoid valve 43,

the second control valve body 41 is provided with a second main chamber 411 and a second side chamber 412, the second control piston assembly 42 is arranged in the second main chamber 411, the second electromagnetic valve 43 is arranged in the second side chamber 412, the third input port 413, the fourth input port 414 and the second output port 415 are all arranged on the second control valve body 41 and are communicated with the second main chamber 411, the second control piston assembly 42 comprises a second control piston rod 421 and a plurality of second control pistons 422 fixed on the second control piston rod 421, the plurality of second control pistons 422 are sequentially and hermetically arranged in the second main chamber 411 along the axial direction of the second control piston rod 421 to divide the second main chamber 411 into a plurality of second sub-chambers, one end of the second control piston rod 421 extends out of the second main chamber 411 and is connected with the second electromagnetic valve 43,

the second output port 415 is located at one side of the radial direction of the second control piston rod 421, the third input port 413 and the fourth input port 414 are located at the other side of the radial direction of the second control piston rod 421, when the second electromagnetic valve 43 is powered on, the second control piston assembly 42 can be driven to move axially until the second output port 415 is communicated with the third input port 413 only through one of the second sub-chambers, and the fourth input port 414 is located in another adjacent second sub-chamber, so that the second control valve 4 is in a second power-on state, when the second electromagnetic valve 43 is powered off, the second control piston assembly 42 can move axially reversely until the second output port 415 is communicated with the fourth input port 414 only through one of the second sub-chambers, and meanwhile the third input port 413 is located in another adjacent second sub-chamber, so that the second control valve 4 is in a second power-off state.

In the present embodiment of the present invention,

the first solenoid valve 33 includes a first suction cup 331, a first coil 332, and a first return spring 333, the first coil 332 being fixed to an outer end wall of the first main chamber 311, the first suction cup 331 being fixed to an end of the first control piston rod 321 extending into the first side chamber 312, the first return spring 333 being connected between a chamber wall of the first side chamber 312 and the first suction cup 331,

when the first electromagnetic valve 33 is powered on, the first suction cup 331 moves towards the first coil 332 to be fixedly connected with the first coil 332 so as to drive the first control piston assembly 32 to axially move until the first control valve 3 is in a first power-on state, the first return spring 333 is elongated, and when the first electromagnetic valve 33 is powered off, the first suction cup 331 is disconnected with the first coil 332 and the first return spring 333 is reset so as to drive the first control piston assembly 32 to axially move until the first control valve 3 is in a first power-off state;

the second solenoid valve 43 includes a second suction cup 431, a second coil 432, and a second return spring 433, the second coil 432 is fixed to the outer end wall of the second main chamber 411, the second suction cup 431 is fixed to one end of the second control piston rod 421 extending into the second side chamber 412, the second return spring 433 is connected between the chamber wall of the second side chamber 412 and the second suction cup 431,

When the second electromagnetic valve 43 is powered, the second sucking disc 431 moves towards the second coil 432 to be fixedly connected with the second coil 432 so as to drive the second control piston assembly 42 to axially move until the second control valve 4 is in the second power-on state, the second reset spring 433 is elongated, and when the second electromagnetic valve 43 is powered off, the second sucking disc 431 is disconnected with the second coil 432 and the second reset spring 433 is reset so as to drive the second control piston assembly 42 to axially move until the second control valve 4 is in the second power-off state.

In this embodiment, the control valve assembly is provided with multiple sets, the first and second channel outlets of the multiple sets of control valve assembly each communicating with the main seal chamber 215 of the main valve 2.

The design that one main valve 2 is matched with two sets of control valve assemblies in parallel can be adopted according to the requirements, the overall reliability of the valve is improved, and valve faults caused by single component faults are prevented.

In this embodiment, a plurality of first electromagnetic valves 33 of the first control valve 3 are provided, the first suction cups 331 of the plurality of first electromagnetic valves 33 are fixedly connected with the first control piston rod 321,

the second electromagnetic valves 43 of the second control valve 4 are provided with a plurality of second sucking discs 431 of the second electromagnetic valves 43, and the second sucking discs 431 of the second electromagnetic valves 43 are fixedly connected with the second control piston rod 421.

And a plurality of solenoid valves connected in series can be arranged on each control valve according to the requirement, so that the control valve faults caused by single solenoid valve faults or power supply faults are prevented.

In this embodiment, the main valve spool 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 28, the main piston rod is slidably disposed in the main valve body, the main piston 25 is fixed on the main piston rod and is located in a main sealing chamber 215, the valve disc 28 is fixed on the main piston rod and is located in a main valve chamber 24, and the main spring 26 is located in the main sealing chamber 215 and is compressed between the main piston 25 and a bottom wall of the main valve chamber 24.

The main valve 2 is a main flow path for fluid when a loop is depressurized, the interior of the valve is subjected to high-temperature and high-pressure fluid, and in order to avoid the influence of the high-temperature fluid and vibration of the loop on a valve control and driving system, the main valve 2 adopts a driving piston and a driving spring as an opening and closing energy source. The main valve 2 is connected to the pilot valve 1 via a pilot line for controlling the pressure in the sealing chamber 215, further controlling the opening and closing of the main valve 2.

In the present embodiment of the present invention,

the main valve cavity 24 is positioned at the lower part of the main sealing cavity 215, a valve inlet 29 and a valve outlet 211 which are respectively communicated with the main valve cavity are arranged on the main valve body, the valve inlet 29 is arranged at the bottom of the main valve body and is used for being communicated with a loop coolant, the valve outlet 211 is arranged at the side surface of the main valve body and is used for being communicated with the atmosphere, the main piston assembly is vertically and slidably arranged in the main valve body,

Pressure setting value P of medium opening main valve 2 into main seal chamber 215 _0main The following is also satisfied: p (P) _0main X (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 28, G is the weight of the main piston assembly, and F is the spring force of the main spring when the main valve 2 is closed.

The main valve in the pressure relief valve group of the invention is opened, closed and kept in tightness by the combined action of a driving spring, a driving piston pressure and a system pressure, and the method comprises the following steps:

the area of the driving piston is larger than that of the valve disc, when the pressure of the sealing chamber is multiplied by the area of the driving piston and the gravity of the piston assembly is multiplied by the pressure of the driving spring and the pressure of the inlet of the valve and the area of the valve disc, the valve is in a closed state, and the sealing of the valve is maintained by means of the differential pressure before and after the inequality;

when the sealing chamber pressure is multiplied by the driving piston area and the gravity of the piston assembly is multiplied by the driving spring pressure and the valve inlet pressure is multiplied by the valve disc area, the valve is opened under the action of the pressure of the driving spring and the internal pressure of the system, and is always in an opened state by the driving spring pressure.

In the present embodiment of the present invention,

the outer diameter of the valve disc 28 tapers from top to bottom, such that the outer wall of the valve disc 28 forms a first conical surface,

the valve inlet 29 is provided with a nozzle 210, the upper part of the inner wall of the nozzle 210 is provided with a second conical surface matched with the first conical surface, and when the main piston assembly moves downwards to be matched with the first conical surface and the second conical surface, the valve disc 28 closes the valve inlet 29.

The valve disc and the nozzle adopt inclined contact surfaces, when the valve is closed, the nozzle and the valve disc can be tightly matched under the action of pressure difference, so that sealing is better maintained, and coolant leakage is prevented.

In the present embodiment of the present invention,

the main valve body comprises a main valve housing 21, a lower valve seat 22 and an upper valve seat 23 which are fixedly connected in sequence from bottom to top, the inner cavity of the main valve housing 21 forms a main valve cavity 24,

the top surface of the lower valve seat 22 is provided with a first groove, the lower part of the upper valve seat 23 extends into the first groove and is connected with the groove wall of the first groove in a sealing way, the bottom surface of the upper valve seat 23 is provided with a second groove, and the groove wall of the second groove and the bottom wall of the first groove are enclosed to form a main sealing cavity 215.

In this embodiment, a pilot conduit 214 is fixed in the upper valve seat 23, one end of the pilot conduit 214 extends into the main seal cavity 215, and the other end extends out of the upper valve seat 23 and is communicated with the first channel and the second channel of the pilot valve 1.

In this embodiment, the main piston rod comprises a working section 27 and a positioning section 213, the lower end of the working section 27 is fixedly connected with a valve disc 28, the upper end of the working section 27 penetrates through the lower valve seat 22 and then extends into the main sealing cavity 215 and is fixedly connected with the main piston 25, the main spring 26 penetrates through the working section 27,

the upper part of the upper valve seat 23 is provided with a sealed exhaust cavity 212, the top of the upper valve seat 23 is provided with a valve cover 216 for opening or closing the exhaust cavity 212, the lower end of the positioning section 213 is fixedly connected with the piston, and the upper end of the positioning section passes through the upper valve seat 23 and then extends into the exhaust cavity 212.

In the present embodiment of the present invention,

the driving structure of the pilot valve 1 comprises a first pilot piston 15, a second pilot piston 110 and a pilot piston rod 16, wherein the pilot piston rod 16 is axially and slidably arranged in the pilot valve body and is connected between the first pilot piston 15 and the second pilot piston 110, the first pilot piston 15 is hermetically and slidably arranged in a first sealing cavity 17, the second pilot piston 110 is hermetically and slidably arranged in a second sealing cavity 112,

the valve core structure comprises a first pilot valve, a second pilot valve and a pilot valve rod 111, wherein the pilot valve rod 111 is arranged in parallel with the pilot piston rod 16 and is connected with the pilot piston rod 16, the axial direction of the pilot valve rod is slidably arranged in the pilot valve body and is connected between the first pilot valve and the second pilot valve, the first pilot valve is arranged in a first channel and is used for opening or closing the first channel, and the second pilot valve is arranged in a second channel and is used for opening or closing the second channel.

In the present embodiment of the present invention,

the first pilot valve comprises a first valve plate 14 and a first valve core component 117, the first valve plate 14 is fixed in the first channel and closes the first channel, a first valve hole is arranged on the first valve plate, the first valve core component 117 is arranged in the first channel in a sliding way and matched with the first valve hole,

the second pilot valve comprises a second valve plate 19 and a second valve core component 118, the second valve plate 19 is fixed in the second channel and closes the second channel, a second valve hole is arranged on the second valve plate, the second valve core component 118 is arranged in the second channel in a sliding way and matched with the second valve hole,

The pilot valve rod 111 is connected to the first valve core assembly 117 and the second valve core assembly 118, and when moving axially, drives the first valve core assembly 117 to open the first valve hole and drives the second valve core assembly 118 to close the second valve hole, or drives the first valve core assembly 117 to close the first valve hole and drives the second valve core assembly 118 to open the second valve hole.

In the present embodiment of the present invention,

the first passage includes a first inlet section, a first pilot valve chamber 120, and a first outlet section, which are sequentially communicated, the first pilot valve is located in the first pilot valve chamber 120, the first pilot valve chamber 20 has a space for the first spool assembly 117 to slide,

the second passage includes a second inlet section, a second pilot valve chamber 121, and a second outlet section that are sequentially communicated, the second outlet section being communicated with the first outlet section, the second pilot valve being located in the second pilot valve chamber 121, the second pilot valve chamber 121 having a space for sliding the second valve spool assembly 118.

In this embodiment, the first valve element assembly 117 and the second valve element assembly 118 each include a valve element and a return spring, the return spring abutting between the valve element and a wall of the corresponding valve chamber,

in the process of axially moving the pilot valve rod 111 to drive the valve core to open the corresponding valve hole, the return spring is compressed, and after the pressure source is withdrawn, the corresponding valve core can be pushed to close the corresponding valve hole in the process of returning the return spring.

In this embodiment, the first inlet section is provided with a first input pipe 115, the second inlet section is provided with a second input pipe 116, the first outlet section is provided with an output pipe 114, and the first input pipe 115, the second input pipe 116 and the output pipe 114 extend out of the pilot valve body.

In this embodiment, the pilot piston rod 16 is connected to the pilot valve rod 111 through a pilot dial 119, and a groove 122 is formed in the pilot valve body to allow the pilot dial 119 to move axially along the pilot piston rod 16.

In this embodiment, the pilot valve body comprises a first valve seat 11, an intermediate valve seat 13 and a second valve seat 12 which are fixedly connected in sequence,

the first seal chamber 17 is provided in the first valve seat 11, the second seal chamber 112 is provided in the second valve seat 12, and the first passage and the second passage are opened in the intermediate valve seat 13.

In the embodiment, the first valve seat 11 is in sealing connection with the middle valve seat 13, a third groove is formed on the end face of one end of the middle valve seat 13, the groove wall of the third groove and the end face of one end of the middle valve seat 13, which faces the first valve seat 11, are enclosed to form a first sealing cavity 17,

the second valve seat 12 is in sealing connection with the middle valve seat 13, a fourth groove is formed in the end face of one end of the second valve seat 13, and the groove wall of the fourth groove and the end face of one end of the middle valve seat 13, facing the second valve seat 12, enclose to form a second sealing cavity 112.

In this embodiment, a first conduit 18 is fixed in the first valve seat 11, one end of the first conduit 18 extends into the first sealing cavity 17, and the other end extends out of the first valve seat 11 for communication with the first output port 315,

a second conduit 113 is fixed in the second valve seat 12, one end of the second conduit 113 extends into the second sealing cavity 112, and the other end extends out of the second valve seat 12 and is used for communicating with the second output port 415.

The pressure relief valve block is used for realizing quick pressure relief of a loop and has the following realization functions:

the pressure control of the double-piston pilot valve is realized through the on-off of the first control valve 3 and the second control valve 4 and the pressure levels of the pressure relief box, the constant pressure source and the primary circuit, and finally the opening and closing of the main valve of the pressure relief valve are controlled.

Assuming that the primary loop pressure is Prcs, prcs=15.5 MPa in the normal running state of the nuclear power plant, the primary loop pressure can be gradually reduced to 0.1MPa under the conditions of normal shutdown and refueling overhaul of the nuclear power plant, the constant pressure source pressure is Pacc, for example, the normal pressure of an injection tank is about 4-5MPa, the pressure of a pressure relief tank is P0, and the normal pressure is 0.1MPa.

When the first electromagnetic valve 33 and the second electromagnetic valve 43 are respectively electrified and powered off, the pressure intensity of each position of the pilot valve 1, the piston pressure intensity of the main valve 2 and the functions realized by the main valve 2 are shown in a table 2.

TABLE 2

Main valve function description:

and (3) manually opening: the nuclear power plant requires an operator to manually open the pressure relief valve in some cases, at which time the first solenoid valve 33 is de-energized and the second solenoid valve 43 is energized, so that the first pilot piston and the second pilot piston are equal in pressure, and equal to Pacc, since the first pilot piston area is larger than the second pilot piston area, the pilot valve stem moves downward, resulting in a main valve piston pressure=p0, at which time the main valve is opened under the action of the drive spring and the primary circuit pressure, and can always maintain the open state.

Standby state: during normal operation of the nuclear power plant, the valve is in this state, when both the first solenoid valve 33 and the second solenoid valve 43 are de-energized, the first pilot piston pressure=pacc, the second pilot piston pressure=prcs, when Prcs>P _0twin Time (P) _0twin In relation to the area ratio of the first pilot piston to the second pilot piston, it is assumed here that the area ratio is 2:1, i.e. P _0twin =2×pacc, about 8-10 MPa), the pilot piston rod moves upward, resulting in a main piston pressure=prcs, when the main valve is in a closed state, due to the main valve piston area being larger than the valve disc area. When Prcs<P _0twin Time (P) _0twin In relation to the area ratio of the first pilot piston to the second pilot piston, it is assumed here that the area ratio is 2:1, i.e. P _0twin =2×pacc, about 8-10 MPa), the pilot piston rod moves downward, resulting in a master piston pressure=p0, the master valve opening.

Isolation under high pressure: when the automatic opening of the relief valve is not desired during the normal depressurization of the primary circuit from 15.5MPa, the isolation of the relief valve is required, the first solenoid valve 33 is in the energized state, the second solenoid valve 43 is in the de-energized state, the first pilot piston pressure=p0, the second pilot piston pressure=prcs, and the pilot piston rod moves upward, resulting in the primary valve piston pressure=prcs, when Prcs is greater than the primary valve opening pressure P, because the primary valve piston area is greater than the valve disc area _0main When the main valve is still closed.

Isolation at low pressure: when the primary circuit pressure is further reduced, prcs is insufficient to maintain the closed state of the main valve, the low-pressure isolation state needs to be switched, at this time, the first electromagnetic valve 33 and the second electromagnetic valve 43 are both electrified, the first pilot piston pressure=p0, and the pilot valve second pilot piston pressure=pacc, and since Pacc is always constant to 4-5MPa, the main valve can be always ensured to be in the closed state all the time under the condition that Prcs < Pacc.

Due to P _0main <Pacc, so that the switching between high-pressure isolation and low-pressure isolation can be practically performed by selecting P according to the design of the main valve _0main- The pressure between Pacc is determined to be about 3MPa, which is slightly lower than the normal pressure of the constant pressure source injection tank.

4) Through different combined configurations such as pilot valve parallel connection design, solenoid valve series connection design, can realize the redundant setting of valve opening, isolation function, prevent the valve trouble that single subassembly trouble led to, improved the holistic reliability of valve.

5) The leakage rate is low, and the pressure applied to the main valve piston is sealed by a loop itself during normal operation.

It is to be understood that the above embodiments are merely illustrative of the application of the principles of the present invention, but not in limitation thereof. Various modifications and improvements may be made by those skilled in the art without departing from the spirit and substance of the invention, and are also considered to be within the scope of the invention.

Claims

1. A valve block for a circuit pressure relief vent, comprising: a main valve (2) and a control valve assembly, the main valve (2) comprising: the main valve body is provided with a main sealing cavity (215) and a main valve cavity (24), the main valve cavity (24) is used for communicating a loop coolant with the atmosphere, one end of the main valve core is positioned in the main sealing cavity (215), the other end of the main valve core is positioned in the main valve cavity (24), the main valve core can slide in the main valve body under the action of pressure of medium entering the main sealing cavity (215) so as to open or close the main valve cavity (24),

the control valve assembly comprises a pilot valve (1), a first control valve (3) and a second control valve (4),

the pilot valve (1) comprises a pilot valve body and a pilot valve core, the pilot valve body is provided with a first sealing cavity (17), a first channel, a second channel and a second sealing cavity (112) which are sequentially arranged, the pilot valve core comprises a driving structure and a valve core structure, one end of the driving structure is positioned in the first sealing cavity (17), the other end of the driving structure is positioned in the second sealing cavity (112), the valve core structure is connected with the driving structure, one end of the valve core structure is positioned in the first channel, the other end of the valve core structure is positioned in the second channel, the driving structure can slide in the pilot valve body under the action of the pressure difference of media entering the first sealing cavity (17) and media entering the second sealing cavity (112) so as to drive the valve core structure to open the first channel and close the second channel or close the first channel and open the second channel, the outlets of the first channel and the second channel are communicated with the main sealing cavity (215),

The first control valve (3) has a first inlet (313), a second inlet (314) and a first outlet (315), the first outlet (315) being in communication with the first sealed chamber (17), the first inlet (313) being in communication with a circuit volume control or pressure relief tank, the second inlet (314) being in communication with a constant pressure source,

the second control valve (4) has a third inlet (413), a fourth inlet (414) and a second outlet (415), said second outlet (415) being in communication with the inlet of the first channel and the second sealed chamber (112), respectively, the third inlet (413) being in communication with a constant pressure source, the fourth inlet (414) being in communication with a circuit coolant,

when the first control valve (3) is electrified, a first output port (315) of the first control valve is communicated with a first input port (313) and is disconnected from a second input port (314), when the first control valve (3) is powered off, a first output port (315) of the first control valve is communicated with the second input port (314) and is disconnected from the first input port (313),

when the second control valve (4) is electrified, the second output port (415) of the second control valve is communicated with the third input port (413) and is disconnected from the fourth input port (414), when the second control valve (4) is powered off, the second output port (415) of the second control valve is communicated with the fourth input port (414) and is disconnected from the third input port (413),

Pressure setting value P of medium in main sealing cavity (215) for opening main valve (2) _0main The method meets the following conditions: p0 < P _0main And Pacc, where P0 is atmospheric pressure, pacc is the pressure of the constant pressure source,

the medium entering the second sealing cavity (112) opens the pressure setting value P of the pilot valve (1) _0twin The method meets the following conditions: pacc×A ₁ ＝P _0twin ×A ₂ Wherein Pacc is the pressure of the constant pressure source, A ₁ Is the cross-sectional area of the first pilot piston (15), A ₂ Is the cross-sectional area of the second pilot piston (110), A ₂ ＜A ₁ 。

2. Valve group for a circuit pressure relief discharge according to claim 1, characterized in that the first control valve (3) comprises a first control valve body (31), a first control piston assembly (32) and a first solenoid valve (33),

the first control valve body (31) is provided with a first main chamber (311) and a first side chamber (312), the first control piston assembly (32) is arranged in the first main chamber (311), the first electromagnetic valve (33) is arranged in the first side chamber (312), the first input port (313), the second input port (314) and the first output port (315) are all arranged on the first control valve body (31) and are communicated with the first main chamber (311), the first control piston assembly (32) comprises a first control piston rod (321) and a plurality of first control pistons (322) fixed on the first control piston rod (321), the plurality of first control pistons (322) are sequentially and hermetically arranged in the first main chamber (311) along the axial direction of the first control piston rod (321) so as to divide the first main chamber (311) into a plurality of first sub-chambers, one end of the first control piston rod (321) extends out of the first main chamber (311) and is connected with the first electromagnetic valve (33),

The first output port (315) is located at one side of the radial direction of the first control piston rod (321), the first input port (313) and the second input port (314) are located at the other side of the radial direction of the first control piston rod (321), when the first electromagnetic valve (33) is powered on, the first control piston assembly (32) can be driven to move axially until the first output port (315) is communicated with the first input port (313) only through one first sub-cavity, meanwhile, the second input port (314) is located in the adjacent other first sub-cavity, so that the first control valve (3) is located in a first power-on state, and when the first electromagnetic valve (33) is powered off, the first control piston assembly (32) can be driven to move axially reversely until the first output port (315) is communicated with the second input port (314) only through one first sub-cavity, and meanwhile, the first input port (313) is located in the adjacent other first sub-cavity, so that the first control valve (3) is located in a first power-off state;

the second control valve (4) comprises a second control valve body (41), a second control piston assembly (42) and a second electromagnetic valve (43),

the second control valve body (41) is provided with a second main chamber (411) and a second side chamber (412), the second control piston assembly (42) is arranged in the second main chamber (411), the second electromagnetic valve (43) is arranged in the second side chamber (412), the third input port (413), the fourth input port (414) and the second output port (415) are all arranged on the second control valve body (41) and are communicated with the second main chamber (411), the second control piston assembly (42) comprises a second control piston rod (421) and a plurality of second control pistons (422) fixed on the second control piston rod (421), the plurality of second control pistons (422) are sequentially and hermetically arranged in the second main chamber (411) along the axial direction of the second control piston rod (421) so as to divide the second main chamber (411) into a plurality of second sub-chambers, one end of the second control piston rod (421) extends out of the second main chamber (411) and is connected with the second electromagnetic valve (43),

The second output port (415) is located at one side of the radial direction of the second control piston rod (421), the third input port (413) and the fourth input port (414) are located at the other side of the radial direction of the second control piston rod (421), when the second electromagnetic valve (43) is powered on, the second control piston assembly (42) can be driven to move axially until the second output port (415) is communicated with the third input port (413) only through one of the second sub-cavities, meanwhile, the fourth input port (414) is located in the adjacent other second sub-cavity, so that the second control valve (4) is located in a second power-on state, and when the second electromagnetic valve (43) is powered off, the second control piston assembly (42) can move axially reversely until the second output port (415) is communicated with the fourth input port (414) only through one of the second sub-cavities, meanwhile, the third input port (413) is located in the adjacent other second sub-cavity, and the second control valve (4) is located in a second power-off state.

3. A valve block for a circuit pressure relief vent as defined in claim 2, wherein,

the first electromagnetic valve (33) comprises a first sucker (331), a first coil (332) and a first return spring (333), the first coil (332) is fixed on the outer end wall of the first main chamber (311), the first sucker (331) is fixed on one end of the first control piston rod (321) extending into the first side chamber (312), the first return spring (333) is connected between the cavity wall of the first side chamber (312) and the first sucker (331),

When the first electromagnetic valve (33) is powered on, the first sucker (331) moves towards the first coil (332) to be fixedly connected with the first coil so as to drive the first control piston assembly (32) to axially move until the first control valve (3) is in a first power-on state, the first reset spring (333) is lengthened, when the first electromagnetic valve (33) is powered off, the first sucker (331) is disconnected with the first coil (332) and the first reset spring (333) is reset so as to drive the first control piston assembly (32) to axially move until the first control valve (3) is in a first power-off state;

the second electromagnetic valve (43) comprises a second sucking disc (431), a second coil (432) and a second return spring (433), the second coil (432) is fixed on the outer end wall of the second main chamber (411), the second sucking disc (431) is fixed on one end of the second control piston rod (421) extending into the second side chamber (412), the second return spring (433) is connected between the cavity wall of the second side chamber (412) and the second sucking disc (431),

when the second electromagnetic valve (43) is powered on, the second sucking disc (431) moves towards the second coil (432) to be fixedly connected with the second coil so as to drive the second control piston assembly (42) to axially move to the second control valve (4) to be in a second power-on state, the second reset spring (433) is stretched, when the second electromagnetic valve (43) is powered off, the second sucking disc (431) is disconnected with the second coil (432) and the second reset spring (433) is reset, and the second control piston assembly (42) is driven to axially move to the second control valve (4) to be in a second power-off state.

4. Valve group for a circuit pressure relief vent according to claim 1, wherein the control valve assembly is provided with multiple sets, the first and second channel outlets of the multiple sets of control valve assembly each communicating with the main sealing chamber (215) of the main valve (2).

5. Valve group for pressure relief discharge of a circuit according to claim 1, characterized in that the first solenoid valves (33) of the first control valve (3) are provided in plurality, the first suction cups (331) of the plurality of first solenoid valves (33) are all fixedly connected with the first control piston rod (321),

the second electromagnetic valves (43) of the second control valves (4) are provided with a plurality of second suckers (431) of the second electromagnetic valves (43) and are fixedly connected with the second control piston rod (421).

6. Valve group for a circuit pressure relief vent according to any one of claims 1-5, wherein the main spool comprises a main piston assembly and a main spring (26), the main piston assembly comprising a main piston rod, a main piston (25) and a valve disc (28), the main piston rod being slidably arranged in the main valve body, the main piston (25) being fixed to the main piston rod and being located in the main sealing chamber (215), the valve disc (28) being fixed to the main piston rod and being located in the main valve chamber (24), the main spring (26) being located in the main sealing chamber (215) and being compressed between the main piston (25) and the bottom wall of the main valve chamber (24).

7. The valve manifold for a circuit pressure relief vent of claim 6, wherein,

the main valve cavity (24) is positioned at the lower part of the main sealing cavity (215), the main valve body is provided with a valve inlet (29) and a valve outlet (211) which are respectively communicated with the main valve cavity, the valve inlet (29) is arranged at the bottom of the main valve body and is used for being communicated with a loop coolant, the valve outlet (211) is arranged at the side surface of the main valve body and is used for being communicated with the atmosphere, the main piston assembly is vertically and slidably arranged in the main valve body,

pressure setting value P of medium in main sealing cavity (215) for opening main valve (2) _0main The following is also satisfied: p (P) _0main X (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 (28), G is the weight of the main piston assembly, and F is the spring force of the main spring when the main valve (2) is closed.

8. The valve manifold for a circuit pressure relief vent of claim 6, wherein,

the outer diameter of the valve disc (28) gradually decreases from top to bottom so that the outer wall of the valve disc (28) forms a first conical surface,

the valve inlet (29) is provided with a nozzle (210), the upper part of the inner wall of the nozzle (210) is provided with a second conical surface matched with the first conical surface, and when the main piston assembly moves downwards to be matched with the first conical surface and the second conical surface, the valve disc (28) closes the valve inlet (29).

9. The valve manifold for a circuit pressure relief vent of claim 6, wherein,

the main valve body comprises a main valve shell (21), a lower valve seat (22) and an upper valve seat (23) which are fixedly connected in sequence from bottom to top, the inner cavity of the main valve shell (21) forms a main valve cavity (24),

the top surface of lower disk seat (22) begins to have first groove, the lower part of going up disk seat (23) stretches into in the first groove and links to each other with the cell wall seal in first groove, the second groove has been seted up to the bottom surface of going up disk seat (23), and the cell wall in second groove encloses with the diapire in first groove and closes and form main seal chamber (215).

10. Valve group for pressure relief and discharge of a circuit according to claim 9, characterized in that said main piston rod comprises a working section (27) and a positioning section (213), the lower end of said working section (27) being fixedly connected to a valve disc (28), the upper end of said working section (27) penetrating through the lower valve seat (22) and extending into the main sealing chamber (215) and being fixedly connected to the main piston (25), said main spring (26) being threaded on the working section (27),

the upper part of the upper valve seat (23) is provided with a sealed exhaust cavity (212), the top of the upper valve seat (23) is provided with a valve cover (216) for opening or closing the exhaust cavity (212), the lower end of the positioning section (213) is fixedly connected with the piston, and the upper end of the positioning section penetrates through the upper valve seat (23) and then stretches into the exhaust cavity (212).

11. A valve block for a circuit pressure relief vent as claimed in any one of claims 1-5, wherein,

the driving structure comprises a first pilot piston (15), a second pilot piston (110) and a pilot piston rod (16), wherein the pilot piston rod (16) is axially arranged in the pilot valve body in a sliding way and is connected between the first pilot piston (15) and the second pilot piston (110), the first pilot piston (15) is arranged in a sealing way in a first sealing cavity (17), the second pilot piston (110) is arranged in a sealing way in a second sealing cavity (112),

the valve core structure comprises a first pilot valve, a second pilot valve and a pilot valve rod (111), wherein the pilot valve rod (111) is arranged in parallel with a pilot piston rod (16) and is connected with the pilot piston rod in a connecting mode, the axial direction of the pilot valve rod is arranged in the pilot valve body in a sliding mode and is connected between the first pilot valve and the second pilot valve, the first pilot valve is arranged in a first channel and is used for opening or closing the first channel, and the second pilot valve is arranged in a second channel and is used for opening or closing the second channel.

12. The valve manifold for a circuit pressure relief vent of claim 11,

the first pilot valve comprises a first valve plate (14) and a first valve core component (117), the first valve plate (14) is fixed in the first channel and closes the first channel, a first valve hole is arranged on the first valve plate, the first valve core component (117) is arranged in the first channel in a sliding way and matched with the first valve hole,

The second pilot valve comprises a second valve plate (19) and a second valve core component (118), the second valve plate (19) is fixed in the second channel and closes the second channel, a second valve hole is arranged on the second valve plate, the second valve core component (118) is arranged in the second channel in a sliding way and matched with the second valve hole,

the pilot valve rod (111) is connected to the first valve core assembly (117) and the second valve core assembly (118), and when the pilot valve rod moves axially, the pilot valve rod drives the first valve core assembly (117) to open the first valve hole and drives the second valve core assembly (118) to close the second valve hole, or drives the first valve core assembly (117) to close the first valve hole and drives the second valve core assembly (118) to open the second valve hole.

13. The valve manifold for a circuit pressure relief vent of claim 12, wherein,

the first passage comprises a first inlet section, a first pilot valve cavity (120) and a first outlet section which are communicated in sequence, the first pilot valve is positioned in the first pilot valve cavity (120), the first pilot valve cavity (20) is provided with a space for the first valve core component (117) to slide,

the second channel comprises a second inlet section, a second pilot valve cavity (121) and a second outlet section which are communicated in sequence, the second outlet section is communicated with the first outlet section, the second pilot valve is positioned in the second pilot valve cavity (121), and the second pilot valve cavity (121) is provided with a space for a second valve core assembly (118) to slide.

14. Valve group for pressure relief and discharge of a circuit according to claim 11, characterized in that said pilot piston rod (16) is connected to the pilot valve stem (111) by means of a pilot dial (119), said pilot valve body being provided with a slot (122) for axial displacement of the pilot dial (119) along the pilot piston rod (16).