WO2024000985A1

WO2024000985A1 - Stepwise pressure relief device and steam generator secondary-loop heat sink system

Info

Publication number: WO2024000985A1
Application number: PCT/CN2022/129915
Authority: WO
Inventors: 赵嘉明; 荆春宁; 赵侠; 吴宇翔; 黄代顺; 丁亮; 曲昌明; 于沛; 彭立; 赵丹峰; 吴永重; 李嫦月; 陆洋; 董业旻; 潘佳琪
Original assignee: 中国核电工程有限公司
Priority date: 2022-06-30
Filing date: 2022-11-04
Publication date: 2024-01-04
Also published as: AR128081A1; CN115206568A

Abstract

A stepwise pressure relief device, comprising a steam intake pipeline, a silencing module and a heat recovery module. The steam intake pipeline comprises a first pipeline and at least two discharge pipelines, wherein the first pipeline is in communication with the silencing module and the heat recovery module, and the at least two discharge pipelines are respectively in communication with both the heat recovery module and the atmosphere. The silencing module is in communication with the heat recovery module and the atmosphere, and the heat recovery module is in communication with the atmosphere and users. A steam generator secondary-loop heat sink system, which has a steam delivery and pressure relief pipeline containing a stepwise pressure relief device. By means of the stepwise pressure relief device and the steam generator secondary-loop heat sink system, the economy, and the economy and safety of a power plant can be improved.

Description

A graded pressure relief device and steam generator secondary loop heat trap system

This application claims the priority of the Chinese patent application submitted on June 30, 2022 with the invention title "A graded pressure relief device and steam launcher secondary loop heat trap system" and the application number 202210756488.5.

Technical field

The invention belongs to the technical field of nuclear plants, and specifically relates to a graded pressure relief device and a steam generator secondary loop heat trap system.

Background technique

In the past nuclear engineering design process, the steam generator secondary loop heat trap system mainly relied on active water supply and steam transportation and exhaust systems to deal with design basis accidents. This places high requirements on the redundancy and reliability of the pumps and water sources of the active water supply system. It also places high requirements on the steam turbine bypass measures, which can be used as a reliable secondary circuit heat sink for a long time. Heat from the reactor coolant system. Comprehensive consideration of the grading, capacity, redundancy, diversity and other aspects of the above configuration results in great challenges and poor economics in terms of personnel and equipment costs, construction and layout space, and large amounts of construction. In addition, the steam in the steam generator secondary loop steam transport and exhaust system is not only used to drive the steam turbine during normal operation, but also a lot of steam discharged through the valve is wasted during other start and stop conditions, resulting in a large amount of heat energy loss. In addition, the pressure relief and discharge device on the secondary side of the steam generator was not considered as a whole, and there were many limitations in valve selection, configuration, setting, and discharge pipeline design. All valves used the same discharge setting, resulting in large vibrations in the discharge force. Strengthening, and there are also problems such as excessive valve redundancy and excessive discharge capacity, which is not conducive to improving the economy and safety of the power plant.

Contents of the invention

In view of the shortcomings in the prior art, the purpose of the present invention is to provide a graded pressure relief device and a steam generator secondary loop heat trap system to cope with the secondary loop heat trap of the design basis accident, and at the same time adopt the design of a depth defense heat trap. Further improve the reliability of heat conduction in power plants. In addition, a graded pressure relief device is used to make the steam emission more stable and reduce vibration. At the same time, the high-temperature steam heat energy is recovered and reused, which not only improves the economy of the power plant, but also improves the safety of the power plant.

In order to achieve the above objectives, the technical solution adopted by the present invention is: a hierarchical pressure relief device, including a steam inlet pipeline, a silencer module and a heat energy recovery module. The steam inlet pipeline includes a first pipeline and at least two exhaust pipelines. The first pipeline is connected to the silencing module and the heat energy recovery module respectively. The at least two discharge pipelines are connected to the heat energy recovery module and to the atmosphere respectively. The silencing module is connected to the heat energy recovery module and the heat recovery module respectively. Connected to the atmosphere, the heat energy recovery module is connected to the atmosphere and each user respectively; wherein, a regulating valve group and a first isolation valve are provided between the first pipeline, the silencer module and the heat energy recovery module, and the silencer A silencer isolation valve is provided between the module and the heat energy recovery module; a safety valve and a second isolation valve are provided in sequence between the at least two discharge lines and the heat recovery module, and the safety valve is provided at the at least At the entrances of the two discharge pipelines, the second isolation valve is provided between the atmospheric section of the at least two discharge pipelines and the heat energy recovery module. The heat energy recovery module is respectively provided with a connection point between the atmosphere and each user. Thermal isolation valve.

Further, the regulating valve group includes a third isolation valve and a silencer regulating valve arranged in sequence to achieve the effects of regulating and isolating exhaust steam.

Further, the second pipeline and the third pipeline are divided into at least two symmetrically arranged rows, respectively discharged to the atmosphere or connected to the heat energy recovery module, and the second isolation valve is provided on the second pipeline and all The third pipeline is connected to the heat energy recovery module.

Further, the opening setting value of the safety valve is higher than the discharge setting value of the regulating valve group; the opening setting value of the safety valve of at least one of the at least two discharge pipelines is different from the at least two discharge pipelines. The opening setting of the safety valve of at least another one of them.

Further, the opening setting value of the safety valve of the one of the at least two discharge pipelines that is farther from the first pipeline is higher than or equal to the opening value of the safety valve of the at least two discharge pipelines that is closer to the first pipeline. The opening setting value of the safety valve of one discharge pipeline causes the opening setting value of all safety valves to gradually increase as a whole.

Further, the discharge height of the safety valve of at least one of the at least two discharge lines is arranged at the same or different elevation as the safety valve of at least another of the at least two discharge lines, and the at least The discharge diameter of the safety valve of at least one of the two discharge lines is the same or different from the discharge diameter of the safety valve of at least another of the at least two discharge lines.

The discharge diameter of the safety valve of the one of the at least two discharge pipelines that is farther from the first pipeline is greater than or equal to the discharge diameter of the one of the at least two discharge lines that is closer to the first pipeline. The discharge diameter of the safety valve of the pipeline causes the overall discharge diameter of all safety valves to gradually increase. Further, the at least two discharge pipelines include a second pipeline and a third pipeline, and the second pipeline includes a first interconnected pipeline. A communication section and a first discharge section, wherein the first communication section is connected with the heat energy recovery module, and the first discharge section is discharged to the atmosphere; the third pipeline includes a second communication section and a second A discharge section, wherein the second communication section is connected to the heat energy recovery module, the second discharge section is discharged to the atmosphere, and the second isolation valves are respectively provided in the first communication section and the second communication section. section.

The invention also provides a steam generator secondary loop heat trap system, which includes: a steam transportation and pressure relief pipeline, which includes a graded pressure relief device; a heat exchange loop, which includes a steam generator, a steam pipeline, a condensation pipeline, and at least one A heat exchanger and at least one hot water exchange tank, the steam generator is connected to the graded pressure relief device; and a water supply pipeline, the water supply pipeline is connected to the steam generator to supply water to the steam generator; Wherein, the steam pipeline is connected to the steam generator and the heat exchanger respectively, the condensation pipeline is connected to the heat exchanger and the water supply pipeline respectively, and the heat exchanger is located in the hot water exchange tank. ; The steam pipeline is provided with a normally open steam isolation valve, and the condensation pipeline is provided with at least two parallel normally closed first condensation isolation valves.

Further, at least one wide-range liquid level measuring instrument and at least one narrow-range liquid level measuring instrument are provided on the steam generator to monitor the liquid level in the steam generator.

Further, at least one differential pressure flow measuring instrument is provided between the steam generator and the staged pressure relief device.

Further, the water supply pipeline includes a main water supply pipeline and a start-stop water supply pipeline, and the main water supply pipeline and the start-stop water supply pipeline are both connected to the steam generator to supply water to the steam generator; The condensation pipeline is connected to the main water supply pipeline and the start-stop water supply pipeline respectively, and a second condensation isolation valve and a third condensation isolation valve are respectively provided at the communication locations.

Further, the main water supply pipeline is provided with a water supply flow measuring device, a water supply regulating valve, a water supply isolation valve and a water supply check valve in sequence. The water supply flow measuring device is also provided with at least one water supply sensor. The water supply regulating valve and The water supply isolation valves all receive water supply isolation signals, and adopt staged isolation based on the hydraulic transient results caused by actual closure.

Furthermore, the start-stop water supply pipeline is provided with a start-stop water supply flow measuring device, a start-stop water supply regulating valve, a start-stop water supply isolation valve, and a start-stop water supply check valve. The start-stop water supply flow measuring device is also provided with a start-stop water supply flow measuring device. There is at least one start-stop water supply sensor, the start-stop water supply regulating valve and the start-stop water supply isolation valve both receive water supply isolation signals, and adopt staged isolation according to the hydraulic transient results caused by actual shutdown.

The effect of the present invention is to reduce personnel and equipment costs, save construction and layout space, and increase economy by comprehensively considering the classification, capacity, redundancy, diversity and other aspects configured in the steam generator secondary loop heat trap system. sex. At the same time, the staged pressure relief device is used not only to push the steam turbine during normal operation, but also to recover the heat energy of the steam discharged through the valve during other start and stop conditions. In addition, the economy and safety of the power plant are improved through valve selection, configuration, setting, and discharge pipeline design.

Description of drawings

Figure 1 is a module schematic diagram of a graded pressure relief device in the present invention;

Figure 2 is a schematic module diagram of a steam generator secondary loop heat trap system in the present invention.

Explanation of reference symbols:

10. Graded pressure relief device; 1. Steam inlet pipeline; 2. Silencing module; 3. Heat recovery module; 11. First pipeline; 12. Second pipeline; 13. Third pipeline; 111. Regulating valve group; 112. The first isolation valve; 21. Silencer isolation valve; 31. Thermal energy isolation valve; 14. Safety valve; 113. The second isolation valve; 114. Silencer regulating valve; 115. The third isolation valve; 121. The first communication section; 122 , the first discharge section; 131, the second connecting section; 132, the second discharge section;

4. Steam generator; 40. Water supply pipeline; 50. Heat exchange circuit; 60. Steam transmission and pressure relief pipeline; 51. Steam pipeline; 52. Condensation pipeline; 53. Heat exchanger; 54. Hot water exchange tank; 511. Steam isolation valve; 521. First condensation isolation valve; 401. Wide-range liquid level measuring instrument; 402. Narrow-range liquid level measuring instrument; 403. Differential pressure flow measuring instrument; 41. Main water supply pipeline; 42. Start-up Stop the water supply pipeline; 522. Second condensation isolation valve; 523. Third condensation isolation valve; 411. Water supply flow measurement device; 412. Water supply regulating valve; 413. Water supply isolation valve; 414. Water supply check valve; 415. Water supply Sensor; 421. Start and stop water supply flow measurement device; 422. Start and stop water supply regulating valve; 423. Start and stop water supply isolation valve; 424. Start and stop water supply check valve; 425. Start and stop water supply sensor.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figures 1-2, the present invention provides a graded pressure relief device 10, which is installed on the steam transportation and pressure relief pipeline of the secondary circuit heat trap of the steam generator, and includes an exhaust pipe on the steam transportation and pressure relief pipeline. The connected steam inlet pipeline 1, silencer module 2 and heat energy recovery module 3. The steam inlet pipeline 1 includes a first pipeline 11, a second pipeline 12 and an optional third pipeline 13. The first pipeline 11 is connected to the silencer module 2 and the thermal energy recovery module 3 respectively. The recovery module 3 is connected. The second pipeline 12 is connected with the heat recovery module 3 and the atmosphere. The silencer module 2 is connected with the heat recovery module 3 and the atmosphere respectively. The heat recovery module 3 is connected with the atmosphere and each user respectively. The steam transportation and pressure relief pipeline is a steam pipeline that can not only transport steam to the steam turbine, but also discharge steam through the pressure relief device under overpressure conditions.

A regulating valve group 111 and a first isolation valve 112 are respectively provided between the first pipeline 11 and the silencer module 2 and the heat energy recovery module 3. A silencer isolation valve 21 is provided between the silencer module 2 and the heat energy recovery module 3. A safety valve 14 and a second isolation valve 113 are arranged in sequence between the second pipeline 12 and the heat recovery module 3. The safety valve 14 is arranged at the inlet of the second pipeline 12, and the second isolation valve 113 is arranged at the second pipeline 12 to connect to the atmosphere. Between the section and the heat energy recovery module 3, thermal energy isolation valves 31 are respectively provided at the points where the heat energy recovery module 3 communicates with the atmosphere and each user. Similar to the second pipeline 12, the third pipeline 13 is connected to the heat energy recovery module 3 and to the atmosphere. A safety valve located at the inlet of the third pipeline 13 is also disposed between the third pipeline 13 and the heat recovery module 3. 14 and the second isolation valve 113 provided between the atmospheric section of the third pipeline 13 and the heat energy recovery module 3 . It can be understood that in some embodiments, a fourth pipeline, a fifth pipeline, etc. similar to the second pipeline 12 may be provided, that is, these more pipelines may also be similarly provided with a safety valve 14 and a second isolation valve. 113, and the number of pipelines can be set as needed without specific restrictions. In addition, it can be understood that each pipeline in the steam inlet pipeline 1, such as the first pipeline 11, the second pipeline 12..., etc., are all connected with the exhaust pipe on the steam transportation and pressure relief pipeline. In some embodiments, the second pipeline 12, the third pipeline 13, the fourth pipeline... are successively further away from the first pipeline 11. In this article, the second pipeline 12, the third pipeline 13, the fourth pipeline, etc. can also be collectively referred to as "discharge pipelines". In this article, “farther from the first pipeline 11 ” means that the position on the exhaust pipe connected to the steam delivery and pressure relief pipeline is farther from the first pipeline 11 .

It can be understood that after the steam in the steam delivery and pressure relief pipeline enters the steam inlet pipeline 1, it enters the silencing module 2 through the first pipeline 11 through the regulating valve group 111, and is discharged to the atmosphere through the silencing module 2 for pressure relief. When the silencer isolation valve 21 is opened, the steam can also enter the heat energy recovery module 3, and the waste heat of the steam can be recovered using the heat energy recovery module 3.

It can be understood that in the staged pressure relief device 10, the opening setting value of the safety valve 14 is higher than the discharge setting value of the regulating valve group 111; in addition, in the staged pressure relief device 10, at least one of all safety valves 14 is different from all safety valves 111. At least one other of the valves 14 has a different discharge pressure setting. For example, the two safety valves 14 on the second pipeline 12 and the third pipeline 13 can be designed according to different discharge pressure settings, and both are equipped with nuclear-level earthquake-resistant power supply. When the pressure of the steam reaches the discharge pressure setting value, the steam enters The second pipeline 12 and/or the third pipeline 13 are discharged into the atmosphere; thereby achieving the effect of graded pressure relief. When the second isolation valve 113 is opened, the steam can also enter the heat energy recovery module 3 , and the waste heat of the steam can be recovered using the heat energy recovery module 3 . In some embodiments, more than two safety valves 14 among all the safety valves on the second pipeline 12 , the third pipeline 13 , the fourth pipeline and optionally more pipelines can be designed according to different discharge pressure settings respectively. . In some embodiments, the opening setting values of all safety valves tend to gradually increase as they move away from the first pipeline 11 , which means that some of the safety valves can have the same opening setting value, as long as all the opening setting values are the same. Just gradually increase the trend. It can be understood that in some embodiments, more than two safety valves 14 among all safety valves on the second pipeline 12 , the third pipeline 13 , the fourth pipeline and optionally more pipelines can be respectively arranged at different elevations. superior. It can be understood that in some embodiments, more than two safety valves 14 among all safety valves on the second pipeline 12 , the third pipeline 13 , the fourth pipeline and optionally more pipelines may have different discharge diameters respectively. . In some embodiments, the discharge diameters of all safety valves tend to gradually increase as they move away from the first pipeline 11 , which means that some of the safety valves may have the same discharge diameter, as long as the discharge diameters of all the safety valves are in the same direction. The overall trend is gradually increasing.

Further, the regulating valve group 111 includes a third isolation valve 115 and a silencer regulating valve 114 arranged in sequence to achieve the effects of regulating and isolating exhaust steam.

It can be understood that the third isolation valve 115 may be an electric isolation valve, a pneumatic isolation valve, a pilot quick-opening valve, etc.

Further, the second pipeline 12 and the optional third pipeline 13 are divided into at least two symmetrically arranged rows, which are respectively discharged to the atmosphere or connected to the heat energy recovery module 3. The second isolation valve 113 is provided on the second pipeline 12 and the third pipeline. The third pipeline 13 is connected to the heat energy recovery module 3. In this specification, the term "at least two rows" means that the second pipeline 12 and optionally more pipelines are connected with at least two pipelines, for example, at least two pipelines are connected to the atmosphere or at least two pipelines are connected to thermal energy. Recycling module 3.

Further, the second pipeline 12 includes a first communication section 121 and a first discharge section 122 that are connected with each other, wherein the first communication section 121 is connected with the heat energy recovery module 3 and the first discharge section 122 is discharged to the atmosphere.

The third pipeline 13 includes a second communication section 131 and a second discharge section 132 that are connected to each other. The second communication section 131 is connected with the heat energy recovery module 3 , the second discharge section 132 is discharged to the atmosphere, and the second isolation valves 113 are respectively provided. on the first communication section 121 and the second communication section 131 .

The invention also provides a steam generator secondary loop heat trap system, which includes a water supply pipeline 40, a heat exchange circuit 50, and a steam transportation and pressure relief pipeline 60. The water supply pipeline 40 is connected to the steam generator 4 of the heat exchange circuit 50. , to supply water to the steam generator 4, which is connected to the graded pressure relief device 10 of the steam delivery and pressure relief pipeline 60. The heat exchange circuit 50 includes a steam pipeline 51, a condensation pipeline 52, at least one heat exchanger 53 and at least one hot water exchange tank 54. The steam pipeline 51 is connected to the steam generator 4 and the heat exchanger 53 respectively, and the condensation pipeline 52 is connected to the heat exchanger respectively. 53 and water supply pipeline 40, the heat exchanger 53 is located in the hot water exchange tank 54.

Among them, the steam pipeline 51 is provided with a normally open steam isolation valve 511, and the condensation pipeline 52 is provided with at least two parallel normally closed first condensation isolation valves 521.

It can be understood that in this embodiment, the steam generated by the steam generator 4 undergoes pressure relief and heat recovery through the staged pressure relief device, and then is discharged to the steam turbine to supply steam to the steam turbine.

Further, at least one wide-range liquid level measuring instrument 401 and at least one narrow-range liquid level measuring instrument 402 are provided on the steam generator 4 to monitor the liquid level in the steam generator 4 .

Further, at least one differential pressure flow measuring instrument 403 is provided between the steam generator 4 and the staged pressure relief device.

It can be understood that the flow signal measured by the differential pressure flow measuring instrument 403 can be sent to the reactor protection system of the power plant for triggering the safety protection signal.

Further, the water supply pipeline 40 includes a main water supply pipeline 41 and a start-stop water supply pipeline 42. The main water supply pipeline 41 and the start-stop water supply pipeline 42 are both connected to the steam generator 4 to supply water to the steam generator 4.

Further, the condensation pipeline 52 is respectively connected with the main water supply pipeline 41 and the start-stop water supply pipeline 42, and a second condensation isolation valve 522 and a third condensation isolation valve 523 are respectively provided at the communication locations.

Further, the main water supply pipeline 41 is provided with a water supply flow measuring device 411, a water supply regulating valve 412, a water supply isolation valve 413 and a water supply check valve 414 in sequence. The water supply flow measuring device 411 is also provided with at least one water supply sensor 415.

Further, the start-stop water supply pipeline 42 is sequentially provided with a start-stop water supply flow measuring device 421, a start-stop water supply regulating valve 422, a start-stop water supply isolation valve 423, and a start-stop water supply check valve 424. The start-stop water supply flow measuring device 421 is also provided with at least one start-stop water supply sensor 425.

It can be understood that the water supply flow measuring device 411 is located in the earthquake-resistant factory building and is designed as nuclear-level earthquake-resistant equipment. The flow signal measured by the water supply sensor 415 can be sent to the power plant reactor protection system to trigger a safety protection signal. The water supply regulating valve 412 is a pneumatic valve. It is also designed to be a gas shut-off, which can realize both the adjustment function and the quick isolation function. The water supply isolation valve 413 can be either an electric isolation valve or a gas-liquid linkage quick-closing isolation valve. The water supply regulating valve 412 and the water supply isolation valve 413 both receive the water supply isolation signal. Based on the hydraulic transient results caused by the actual closure, staged isolation can be adopted. Both the water supply isolation valve 413 and the water supply regulating valve 412 receive the water supply isolation signal. Based on the hydraulic transient results caused by the actual closure, staged isolation can be adopted. The feed water isolation valve 413 is arranged as close as possible to the containment penetration, and the feed water check valve 414 is arranged as close as possible to the steam generator 4 and is located upstream of the heat exchange circuit 50 .

It can be understood that the start-stop water supply flow measurement device 421 is located in the earthquake-resistant factory building and is designed as a nuclear-level anti-seismic equipment. The flow signal measured by the start-stop water supply sensor 425 can be sent to the power plant reactor protection system to trigger safety protection signals and start-stop water supply adjustment. Valve 422 is a pneumatic valve and is designed to be shut off when it loses air. It can realize both the adjustment function and the quick isolation function. The start and stop water supply isolation valve 423 can be either an electric isolation valve or a gas-liquid linkage quick-closing isolation valve. Both the start-stop water supply regulating valve 422 and the start-stop water supply isolation valve 423 receive the water supply isolation signal. Based on the hydraulic transient results caused by the actual shutdown, staged isolation can be adopted. Both the start-stop water supply isolation valve 423 and the start-stop water supply regulating valve 422 receive the water supply isolation signal. Based on the hydraulic transient results caused by the actual shutdown, phased isolation can be adopted. The start-stop water supply isolation valve 423 is arranged as close as possible to the containment penetration, and the start-stop water supply check valve 424 is arranged as close as possible to the steam generator 4 and is located upstream of the heat exchange circuit 50 .

In this embodiment, under normal operating conditions of the nuclear power plant, water is supplied to the steam generator 4 through the main water supply pipeline 41. After heat exchange on the secondary side of the steam generator 4, water is supplied to the steam generator 4 through the steam transportation and pressure relief pipeline 60. Into the direction of the steam turbine, it serves as a secondary heat sink during normal operation of the plant. Under the start-up and stop operating conditions of the nuclear power plant, water is supplied to the steam generator 4 through the start-stop water supply pipeline. After the heat exchange on the secondary side of the steam generator 4, normal steam is discharged to the condenser and is unavailable. The steam is decompressed in stages. It is discharged from device 10 and serves as a secondary heat sink during power plant start-up and shutdown operations. The regulating valve on the water supply pipeline 40 is used to adjust the flow of water supply to the steam generator 4 .

When steam is discharged through the staged pressure relief device 10, the staged pressure relief device 10 is mainly used in situations where the power plant starts and stops or is in a hot standby stage for a long time and the steam is non-radioactive. When the steam passes through the regulating valve group 111, it first enters the silencer module 2 for noise reduction processing, and then the steam is discharged into the heat recovery module 3. The steam can also be discharged directly to the heat recovery module 3 according to the needs of the heat exchange user without reducing noise. . Multiple high-voltage energy storage modules can be installed in the heat recovery module 3. Finally, according to the needs of users, the heat is distributed by switching and adjusting the isolation valves and regulating valves on the pipelines leading to each user, and the steam is transported to each user. Each user can then cool down the received steam as needed. Use pressure.

The opening setting value of the safety valve 14 in the staged pressure relief device 10 is higher than the discharge setting value of the regulating valve group 111, and the opening setting values of the safety valves 14 are different and increase step by step. Under different transient conditions, the safety valve 14 will be opened step by step according to the system pressure changes. The maximum opening pressure must be set to ensure that the secondary side does not exceed the pressure limit under different accident conditions. At the same time, the discharge pipeline of the safety valve 14 is discharged symmetrically in two rows, which can balance the valve outlet reaction force, reduce the load on the main steam pipeline, minimize the vibration when the valve is opened, and different numbers of valves can be put into operation for different accidents. Achieve optimal operation. This makes steam discharge more reliable and stable, with less vibration.

The safety valve 14 in the graded pressure relief device 10 has a relatively large discharge capacity. In addition to serving as a heat trap to discharge heat, it is mainly used for overpressure protection. Steam is generally discharged directly to the atmosphere through the safety valve 14. Without affecting the completion of the above functions, the discharge of the safety valve 14 can also be discharged to the heat recovery module 3, and the discharge of different safety valves 14 is arranged at different heights, and the discharge diameter can also be gradually increased to reduce the discharge back pressure. Such a setting can avoid the impact and local pressure surge caused by the concentration of emissions in the same area.

When a nuclear power plant is in a design basis accident situation, the main water supply is lost first due to loss of off-site power and other circumstances, and the main water supply pipeline 41 is isolated. Then water is supplied to the steam generator 4 through the start-stop water supply pipeline 42. After the heat exchange on the secondary side of the steam generator 4, when the normal steam is discharged to the condenser and is unavailable, the steam is discharged in the staged pressure relief device 10 as a power plant. Secondary heat traps for defense in depth during outages, thus avoiding the commissioning of passive heat exchange systems. The safety and reliability of the power plant are further improved. Among them, when the steam is discharged through the staged pressure relief device 10, according to the analysis of the actual accident situation, if the steam is not discharged and can be in the recovery period for a long time, heat recovery and utilization can be considered, otherwise it will be discharged directly.

When a nuclear power plant is in a design basis accident situation, the main water supply is lost first due to loss of off-site power and other circumstances, and the main water supply pipeline 41 is isolated. Then, water is supplied to the steam generator 4 through the start-stop water supply pipeline 42. If the start-stop water supply is lost, the start-stop water supply pipeline 42 is isolated. The low-flow water supply signal on the start-stop water supply pipeline 42 is sent to the reactor protection system, and is used to trigger valves that need to be closed and opened for the operation of the passive heat exchange circuit. It is necessary to send a closing signal to the regulating valve and isolation valve on the main water supply pipeline 41, to send a closing signal to the water supply regulating valve 412 and the water supply isolation valve 413 on the start and stop water supply pipeline 42, and to send a closing signal to the main steam isolation valve. . It is necessary to send two parallel normally closed first condensation isolation valves 521 on the condensation pipeline 52 in the heat exchange circuit 50 and a normally open third condensation isolation valve 523 on the condensation pipeline 52 leading to the start-stop water supply pipeline 42. Turn on the signal. These valves and signals are powered by nuclear-grade reliable batteries. Even if a single fault occurs in the above-mentioned normally closed electric valve or closed pneumatic valve, another valve can still isolate the operation boundary of the passive heat exchange circuit. After the heat exchange circuit 50 is put into operation, the steam from the secondary circuit enters the heat exchanger 53 through the steam pipeline 51, and then transfers the heat to the hot water exchange tank 54. The steam is condensed into water, and then passes through the condensation pipeline 52, and the condensed water passes through the start-stop system. The water supply pipeline 42 supplies the steam generator 4. If the start-stop water supply pipeline 42 loop fails, the pipeline can be isolated, and then the second condensation isolation valve 522 on the condensation pipeline 52 connected to the main water supply pipeline 41 can be opened. , continue to supply water to the steam generator 4, forming a passive closed natural cycle. The heat exchange circuit 50 serves as the secondary circuit heat sink of the steam generator under design basis accident, ensuring the safe operation of the nuclear power plant under accident conditions.

When the nuclear power plant is in a transient or accident situation, the regulating valve group 111 in the staged pressure relief device 10 opens at a lower setting. In addition to adjusting the steam discharge capacity and stabilizing the pressure of the primary and secondary circuits, it is also used to achieve depth defense heat export. function to avoid putting the passive heat exchange circuit into operation. In addition, it is also used to realize the function of defense-in-depth overpressure protection and prevent the safety valve 14 from being put into operation.

During a nuclear power plant accident, such as an SGTR situation, when radioactivity is identified and there is a signal such as a high water level in the steam generator 4, the steam generator 4 is shut down by closing the feed water isolation valve 413 of the accident steam generator 4 and starting and stopping the feed water isolation valve 423. Isolation, and under this pressure, the safety valve 14 and the discharge valve in the graded pressure relief device 10 can be in a closed state to realize automatic isolation of the damaged steam generator 4 and avoid the outward release of radioactivity. Ensure the safety of personnel, power plants and the environment.

The system's graded pressure relief device 10 optimizes the number of valve openings under transient and accident conditions, avoids vibrations caused by simultaneous opening of valves for discharge or pressure relief, and can recover part of the heat of high-temperature and high-pressure steam. At the same time, the high-temperature steam heat energy is recovered and reused, which not only improves the economy of the power plant, but also improves the safety of the power plant.

It can be seen from the above embodiments that the advantages of the present invention include:

(1) Use a safer and more reliable passive heat exchange circuit that uses density difference and gravity to form a natural circulation as a secondary circuit heat trap to deal with design basis accidents. At the same time, when the main water supply pipeline 41 is lost, the start-stop water supply pipeline 42 and the graded pressure relief device 10 are used in conjunction with heat conduction as a depth defense heat trap for the secondary circuit of the steam generator to prevent the passive heat exchange circuit 50 from being put into operation, further improving Power plant safety and reliability. It avoids the cumbersome and complex design caused by using active systems to deal with design basis accidents in the past, and avoids the personnel and equipment costs, construction and layout due to comprehensive considerations of equipment classification, capacity, redundancy, diversity and other aspects in the above design. Space and massive construction pose huge challenges in terms of economic improvement. This secondary circuit heat trap system improves the overall economy and safety of the power plant.

(2) Use a graded pressure relief device 10, which includes at least one regulating valve group 111 that can adjust and isolate exhaust steam pressure relief, and at least one safety valve 14 that can directly discharge. The number of valves should be based on the discharge of the valve. Volume and accident analysis and optimization are determined. The above discharge valves are designed according to different opening pressure settings. The maximum opening pressure setting of the graded pressure relief device 10 should ensure that the secondary side does not exceed the pressure limit under different accident conditions. At the same time, the discharge pipeline of the safety valve 14 is set to more than two rows and discharges symmetrically, which can balance the valve outlet reaction force, reduce the load on the main steam pipeline, minimize the vibration when the valve is opened, and can be put into operation in different quantities according to different accidents valves for optimal operation. This makes steam discharge more reliable and stable, with less vibration.

(3) Use a staged pressure relief device 10, which includes at least one silencer module and at least one heat recovery module. Among them, the silencer module 2 can be equipped with multi-stage silencers according to the needs of the power plant, and can be equipped with modules with different silencers. This flexible setting can consider different levels of silencers according to the user's on-site needs, and optimize the equipment as much as possible according to the user's needs. , and help improve the economics of power plants. The heat recovery module 3 includes at least one heat storage module. Taking into account the discharge pipelines discharged into the module, the discharge heights are set at different elevations, and different discharge pipe diameters are set. The final size determined through simulation calculations, in addition to meeting the discharge requirements and heat recovery requirements, and also avoids the problems of excessive impact and excessive pressure increase due to concentrated discharge at the same location. According to the user's needs, the recovered heat can be flow adjusted and pressure reduced through the regulating valve group 111. If necessary, the user can be isolated through an isolation valve, and a cooling device can also be installed within the user's range. Through the above configuration, the steam coming out of the heat recovery module 3 can meet different user needs, including conventional high-temperature and high-pressure steam sterilization in the power plant and cleaning of oil-containing pipelines, as well as secondary loop deaerators in the power plant. Thermal deaeration, etc. can reduce the unavailability period of the secondary circuit, reduce the use time of the electric boiler, save energy, etc.

(4) Use a staged pressure relief device 10, in which the third isolation valve 115 and the silencer regulating valve 114 in the regulating valve group 111 that can adjust and isolate the exhaust steam pressure relief can be combined with a variety of valve types according to the actual conditions of the power plant. The safety valve 14 can be spring-operated or pilot-operated according to the actual conditions of the power plant. The staged discharge of these valves can ensure the integrity of the steam generator 4 shell side, connecting piping, and equipment that performs safety-related functions of containment isolation and steam generator 4 isolation under various operating conditions of the power plant. The regulating valve group 111, which can adjust and isolate exhaust steam pressure relief, can be used to regulate and export heat, and can also control the stability of the primary and secondary circuits of nuclear power. It can also be used as an in-depth defense measure for secondary circuit overpressure protection and decay heat export. , further improving the reliability of power plants.

(5) The regulating valve in the water supply pipeline 40 has the function of regulating and isolating the water supply at the same time. Therefore, the regulating valve and the isolation valve are equivalent to setting up two nuclear-level reliable water supply isolation valves to prevent the steam generator from overflowing in the event of an SGTR accident. , and the main steam pipeline is overflowing with water. Avoid the release of radioactive materials caused by the valves in the staged pressure relief device 10 discharging feed water and reactor coolant into the atmosphere. At the same time, it serves as a reliable boundary isolation valve for the operation of passive heat exchange circuits. The main steam isolation valve on the steam pipeline can use a gas-liquid linkage isolation valve with two-way control loops to achieve reliable steam isolation, and at the same time, it can be used as a reliable boundary isolation valve for the operation of the passive heat exchange circuit. At the same time, a reliable safety valve is used in the graded pressure relief device 10 on the steam pipeline. When overpressure protection is not required, it can be switched to a closed state and remain closed to maintain a closed isolation state. The valve group in the graded pressure relief device 10 that can adjust and isolate the exhaust steam pressure relief adopts the design of isolation valve and regulating valve, which is equivalent to having two isolation measures and maintaining an edge-sealed isolation valve device. The above-mentioned valves in the staged pressure relief device 10 can be used as reliable boundary isolation valves for the operation of the passive heat exchange circuit.

The device described in the present invention is not limited to the examples described in the specific implementation modes. Those skilled in the art can derive other implementation modes based on the technical solutions of the present invention, which also fall within the scope of technical innovation of the present invention.

Claims

A graded pressure relief device is provided on the steam transportation and pressure relief pipeline, and is characterized by including:

Steam inlet pipeline (1), silencer module (2) and heat recovery module (3),

Wherein, the steam inlet pipeline (1) includes a first pipeline (11) and at least two exhaust pipelines, and the first pipeline (11) is connected to the silencer module (2) and the heat energy recovery module (3) respectively. Connected, the at least two discharge pipelines are respectively connected with the heat energy recovery module (3) and are connected with the atmosphere, the silencer module (2) is connected with the heat energy recovery module (3) and the atmosphere respectively, and the thermal energy The recycling module (3) is connected to the atmosphere and each user respectively;

Among them, a regulating valve group (111) and a first isolation valve (112) are provided between the first pipeline (11), the silencing module (2) and the heat energy recovery module (3). The silencing module (2) A silencer isolation valve (21) is provided between the heat recovery module (3) and a safety valve (14) and a safety valve (14) are provided between the at least two discharge lines and the heat recovery module (3). The second isolation valve (113), the safety valve (14) is provided at the inlet of the at least two discharge pipelines, the second isolation valve (113) is provided at the connection between the atmospheric section and the atmosphere section of the at least two discharge pipelines. Between the heat energy recovery modules (3), thermal energy isolation valves (31) are respectively provided at the points where the heat energy recovery module (3) communicates with the atmosphere and each user.
A graded pressure relief device as claimed in claim 1, characterized in that:

The at least two discharge lines are divided into at least two symmetrically arranged rows, which are respectively discharged to the atmosphere or connected to the heat energy recovery module (3).
A graded pressure relief device as claimed in claim 1, characterized in that:

The opening setting value of the safety valve (14) is higher than the discharge setting value of the regulating valve group (111);

The opening setting of the safety valve of at least one of the at least two discharge lines is different from the opening setting of the safety valve of at least another of the at least two discharge lines.
A graded pressure relief device as claimed in claim 3, characterized in that:

The opening setting value of the safety valve of the one of the at least two discharge pipelines that is farther from the first pipeline is higher than or equal to the opening value of the safety valve of the one of the at least two discharge pipelines that is closer to the first pipeline. The opening setting value of the safety valve of the discharge pipeline causes the opening setting value of all safety valves to gradually increase as a whole.
A graded pressure relief device as claimed in claim 3, characterized in that:

The discharge height of the safety valve (14) of at least one of the at least two discharge lines is arranged at the same or different elevation as the safety valve of at least another of the at least two discharge lines, and the The discharge diameter of the safety valve (14) of at least one of the at least two discharge lines is the same or different from the discharge diameter of the safety valve (14) of at least another of the at least two discharge lines.
A graded pressure relief device as claimed in claim 5, characterized in that:

The discharge diameter of the safety valve of the one of the at least two discharge pipelines that is farther from the first pipeline is greater than or equal to the discharge diameter of the one of the at least two discharge lines that is closer to the first pipeline. The discharge diameter of the safety valve in the pipeline causes the overall discharge diameter of all safety valves to gradually increase.
A steam generator secondary loop heat trap system, which is characterized by including:

Steam delivery and pressure relief pipeline (60), which includes a staged pressure relief device (10);

Heat exchange circuit (50), which includes a steam generator (4), a steam pipeline (51), a condensation pipeline (52), at least one heat exchanger (53) and at least one hot water exchange tank (54). The steam The generator (4) is connected to the graded pressure relief device (10); and

Water supply pipeline (40), the water supply pipeline (40) is connected to the steam generator (4) to supply water to the steam generator (4);

Wherein, the steam pipeline (51) is connected to the steam generator (4) and the heat exchanger (53) respectively, and the condensation pipeline (52) is connected to the heat exchanger (53) and the water supply respectively. Pipeline (40), the heat exchanger (53) is located in the hot water exchange tank (54);

The steam pipeline (51) is provided with a normally open steam isolation valve (511), and the condensation pipeline (52) is provided with at least two parallel normally closed first condensation isolation valves (521).
A steam generator secondary loop heat trap system as claimed in claim 7, characterized in that:

The water supply pipeline (40) includes a main water supply pipeline (41) and a start-stop water supply pipeline (42). The main water supply pipeline (41) and the start-stop water supply pipeline (42) are both related to the above-mentioned water supply pipeline (41). The steam generator (4) is connected to supply water to the steam generator (4);

The condensation pipeline (52) is respectively connected with the main water supply pipeline (41) and the start-stop water supply pipeline (42), and a second condensation isolation valve (522) and a third condensation isolation valve (522) are respectively provided at the communication locations. Isolation valve (523).
A steam generator secondary loop heat trap system as claimed in claim 8, characterized in that:

The main water supply pipeline (41) is provided with a water supply regulating valve (412) and a water supply isolation valve (413). The water supply regulating valve (412) and the water supply isolation valve (413) both receive water supply isolation signals. According to Staged isolation is used as a result of hydraulic transients caused by actual shutdown.
A steam generator secondary loop heat trap system as claimed in claim 8, characterized in that;

The start-stop water supply pipeline (42) is provided with a start-stop water supply regulating valve (422) and a start-stop water supply isolation valve (423). The start-stop water supply regulating valve (422) and the start-stop water supply isolation valve (423) are provided. 423) all accept the water supply isolation signal, and adopt staged isolation based on the hydraulic transient results caused by the actual shutdown.