CN-116624614-B - Medium self-driven main steam quick-closing isolation valve for nuclear power plant

Abstract

The invention belongs to the field of valve engineering design of nuclear power plants, and particularly relates to a medium self-driven main steam quick-closing isolation valve for a nuclear power plant. The valve comprises a valve body, a piston cylinder, a valve rod and a valve cover, wherein the valve cover is connected with the valve body, a piston cylinder sleeve is arranged in the valve body and fixed on the valve cover, the valve rod is sleeved in the piston cylinder, the upper end of the valve rod penetrates through the middle of the valve cover and is connected with a coupler, an upper guide sleeve is arranged on the valve cover, the upper part of the coupler is connected with a limiter assembly, the coupler and the limiter assembly are covered in a bracket cover, and the bracket cover is connected with the top of the valve cover. The invention has the advantages of higher valve closing speed, compact structural design, small size, uniform mass distribution, no external drive pipeline, good integral rigidity and high shock resistance.

Inventors

• ZHANG FUHAI
• ZHANG RUI
• CHANG ZHENGKE
• WANG QIFENG
• MENG JIN
• ZANG JIALIN
• HU YINLONG
• YU LIHONG
• CHEN SHIJIAN
• WANG ZHIMIN
• ZHU JINGMEI
• SU LIHUA

Assignees

• 核电运行研究(上海)有限公司

Dates

Publication Date

20260512

Application Date

20230523

Claims (8)

1. 1. A medium self-driven main steam quick-closing isolation valve for a nuclear power plant is characterized in that: the valve comprises a valve body, a piston cylinder, a valve rod and a valve cover, wherein the valve cover is connected with the valve body, a piston cylinder sleeve is arranged in the valve body and is fixed on the valve cover, the valve rod is sleeved in the piston cylinder, the upper end of the valve rod passes through the middle of the valve cover and is connected with a coupler, an upper guide sleeve is arranged on the valve cover, the upper part of the coupler is connected with a limiter assembly, the coupler and the limiter assembly are covered in a bracket cover, and the bracket cover is connected to the top of the valve cover; The valve rod is of a rod-shaped structure, the middle of the valve rod is provided with a bulge part, the piston cylinder sleeve is arranged outside the valve rod and provides guidance for the movement of the middle bulge part of the valve rod, the lower guide sleeve is sleeved on the rod-shaped part of the valve rod and provides guidance for the movement of the valve rod, the piston ring is arranged on the piston cylinder, and the lower guide sleeve is arranged on the piston cylinder through a second screw and is fixed by a second stop gasket; The valve position indicator is arranged on the top of the valve rod, the limiter assembly is arranged on the top of the valve rod and used for limiting the axial movement position of the valve rod, and the valve cover is provided with an inclined flow passage which is connected with a cavity formed between the upper part of the valve rod and the valve cover.
2. 2. The medium self-driven main steam quick closing isolation valve for a nuclear power plant according to claim 1, wherein the edge of the valve cover is connected with the top of the valve body through a first fastener, and the first fastener comprises a first bolt, a first washer and a first nut.
3. 3. The medium self-driven main steam quick closing isolation valve for a nuclear power plant as set forth in claim 1, wherein a second pin is fixed between the edge of the valve cover and the top of the valve body, and a first gasket is used to seal the valve.
4. 4. A medium self-driven main steam quick closing isolation valve for a nuclear power plant as set forth in claim 1, wherein said piston is housed in a valve body and is secured to a valve cover by a second fastener, said second fastener comprising a third bolt, a third washer and a third nut and being positioned by means of a first pin, both ends of which are inserted into the valve cover and the piston cylinder, respectively.
5. 5. The medium self-driven main steam quick closing isolation valve for a nuclear power plant according to claim 1, wherein the upper guide sleeve is arranged on the valve cover through a first screw and is fixed by a first stop gasket.
6. 6. The medium self-driven main steam quick closing isolation valve for a nuclear power plant according to claim 1, wherein the bracket cover is connected to the top of the valve cover through a third fastening piece, the third fastening piece comprises a second bolt, a second gasket and a second nut, and the second gasket is used for sealing.
7. 7. The medium self-driven main steam quick closing isolation valve for a nuclear power plant according to claim 1, wherein the number of the piston rings is 1 or more, and the sealing between the piston cylinder and the valve body is realized.
8. 8. The medium self-driven main steam quick closing isolation valve for a nuclear power plant according to claim 1, wherein the lower guide sleeve is arranged on the piston cylinder through a second screw and is fixed by a second stop gasket.

Description

Medium self-driven main steam quick-closing isolation valve for nuclear power plant Technical Field The invention belongs to the field of valve engineering design of nuclear power plants, and particularly relates to a medium self-driven main steam quick-closing isolation valve for a nuclear power plant. Background In a main steam pipeline system of a pressurized water reactor nuclear power station, a main steam isolation valve is arranged on a main steam pipeline of a secondary loop outside a containment, and a main steam isolation valve is arranged on each main steam pipeline, and belongs to nuclear 2-level equipment. Under normal steady-state operation condition, the main steam isolation valve is kept at a full-open position to realize the circulation of steam, and under abnormal or accident condition (such as main steam pipeline breakage, etc.), after receiving an isolation signal, the main steam isolation valve can be quickly closed to realize the quick isolation of the steam generator and the main steam pipeline. In the development process of the main steam isolation valve, the main steam isolation valve of a Y-shaped stop valve power distribution power driving type, a Y-shaped stop valve power distribution driving type and a spring energy storage type, a gas-liquid linkage mechanism gate valve type, a self-medium driving type and a check valve type appears in sequence. The main steam isolation valve of the nuclear power station which is running or built in the world at present is mostly in a gate valve structure type using a gas-liquid linkage driving mechanism, and the main valve type is in a double-gate plate gate valve structure. Practical engineering experience shows that the gate valve of the gas-liquid linkage mechanism has the following main defects: (1) The driving mechanism has large volume, large weight and uneven mass distribution, a large number of external driving pipelines are arranged, and the whole arrangement and the anti-seismic bracket are complex in arrangement and large in occupied space; (2) The driving mechanism uses hydraulic oil to store energy through the piston compressed nitrogen cavity and drives the device by means of the energy stored in the nitrogen cavity, an oil loop for pressurizing and maintaining the pressure of the nitrogen is always under high pressure, internal leakage of the electromagnetic valve and leakage defects of all joints are controlled to frequently occur, when the electromagnetic valve is in leakage, the oil pump is frequently pressurized, the oil quality needs to be carefully maintained, and the problem of blocking of the electromagnetic valve caused by oil deterioration occurs; (3) The maintenance process is complex, the difficulty is high, the construction period is long, the maintenance is carried out by returning spare parts to factories, the maintenance cost is high, and the optimization of the unit refueling overhaul construction period is not facilitated; (4) The control part of the driving mechanism comprises a large number of hydraulic components such as electromagnetic valves, check valves, pressure transmitters and the like, and has poor reliability; (5) The air cylinder pressure of the driving mechanism is obviously influenced by the ambient temperature, and the failure alarm rate of oil pressure fluctuation is higher when the temperature changes; (6) The driving mechanism relates to an independent driving pump, a filter and the like, is easy to leak and block, and affects the safe operation of the valve; (7) The driving needs to use a large amount of hydraulic oil, the hydraulic oil leaks to the hot surface of the main steam pipeline to introduce a large fire hazard for the factory building, and the nuclear power plant has similar fire hazard cases; (8) The structure of the gate valve determines that a position space of a valve plate needs to be reserved in an upper cavity of a valve body when the valve is in a full-open position, the structure can form swirling flow and vortex flow of a local flow field, flow induced vibration is a common characteristic of a large-caliber gate valve used in a main steam system of a nuclear power plant, vibration can cause abrasion between the valve plate and a valve seat part or an anti-rotation pin, abrasion between a valve plate hanging frame and a guide rail is high, maintenance workload is high, the defects can influence tightness when the valve is closed, screw connection is used between the valve plate of the gate valve and the hanging frame, screw connection failure occurs under long-term vibration, and the valve plate falls. (10) The valve rod adopts the packing to seal, has the leakage risk. Therefore, the novel main steam quick-closing isolation valve which can meet the requirements of main steam systems of nuclear power plants with the level of millions of kilowatts and above and can effectively solve the defects of poor anti-seismic performance and complex design of a driving mechanism and s