Sealing detection method for steam exhaust valve of steam turbine of main feed pump of nuclear power station

Abstract

The invention provides a sealing detection method for a steam exhaust valve of a steam turbine of a main feed pump of a nuclear power station. The sealing detection method comprises the following steps: closing an air inlet valve and the steam exhaust valve of the steam turbine; liquid is continuously injected into the steam exhaust valve; liquid is injected into the lyophobic container, so that the lyophobic container is in a water seal state; starting a vacuum pump to enable the condenser to be in a vacuum state; an air inlet valve for detection of the steam turbine is opened, so that external air enters the steam turbine; if the pressure value of the first pressure gauge is larger than or equal to the first target value and the pressure value of the second pressure gauge is smaller than or equal to the second target value, the sealing performance of the steam exhaust valve is qualified, and otherwise, the sealing performance of the steam exhaust valve is unqualified. The method is simple and convenient to operate and easy to implement, and the sealing performance of the steam exhaust valve can be accurately judged according to the air pressure changes of the first pressure gauge and the second pressure gauge, so that the maintenance work risk caused by poor sealing of the steam exhaust valve is effectively avoided, and the operation safety and reliability of the nuclear power station are improved.

Description

Technical Field

[0001] This application belongs to the field of nuclear power technology. More specifically, it relates to a method for detecting the seal of the exhaust valve of the main feed water pump steam turbine in a nuclear power plant. Background Art

[0002] The exhaust steam of the main feed water pump steam turbine in a nuclear power plant is discharged to the condenser. An exhaust valve is installed on the exhaust pipe of the steam turbine. This valve is a manual butterfly valve. Its function is to close the valve when the steam side of the steam turbine is under maintenance isolation, isolate the steam side of the steam turbine from the condenser, and prevent the vacuum of the condenser from being affected during the maintenance of the steam side of the steam turbine.

[0003] When it is necessary to perform maintenance on the steam side of the steam turbine, it is necessary to ensure that the seal of the exhaust valve of the steam turbine is in good condition in order to perform steam side isolation maintenance without destroying the vacuum. Otherwise, the unit must be shut down and the vacuum must be broken to perform the steam side maintenance work of the steam turbine. Therefore, the good seal of the exhaust valve of the steam turbine is a key condition for the steam side maintenance of the steam turbine.

[0004] Currently, the diameter of the exhaust valve of the steam turbine is about 2 meters, which is the largest valve in the nuclear power plant. For such a large valve, it is impossible to determine its sealing performance, which also makes the daily maintenance work on the steam side of the steam turbine extremely difficult. Historically, the seal of the exhaust valve has never been verified, and there is no mature and reliable verification method. Therefore, it is necessary to study a set of mature and reliable valve seal verification methods to accurately judge the sealing performance of this valve. Summary of the Invention

[0005] The purpose of the embodiments of this application is to provide a method for detecting the seal of the exhaust valve of the main feed water pump steam turbine in a nuclear power plant, so as to solve the technical problem in the prior art that the seal of the exhaust valve cannot be detected.

[0006] To achieve the above purpose, the technical solution adopted in this application is: to provide a method for detecting the seal of the exhaust valve of the main feed water pump steam turbine in a nuclear power plant, and the seal detection method includes:

[0007] Close the intake valve and the exhaust valve of the steam turbine;

[0008] Continuously inject liquid into the exhaust valve;

[0009] Inject liquid into the liquid drainage container to make the liquid drainage container in a water seal state;

[0010] Start the vacuum pump to make the condenser in a vacuum state;

[0011] Open the intake valve for detection of the steam turbine to allow external air to enter the steam turbine;

[0012] If the pressure value of the first pressure gauge used to detect the internal pressure of the steam turbine is greater than or equal to the first target value, and the pressure value of the second pressure gauge used to detect the internal pressure of the condenser is less than or equal to the second target value, then the sealing performance of the exhaust valve is qualified; otherwise, the sealing performance of the exhaust valve is unqualified.

[0013] Further, continuously injecting liquid into the exhaust valve is performed by the demineralized and deoxygenated liquid supply device.

[0014] Further, in the step of continuously injecting liquid into the exhaust valve, a temporary liquid replenishing device is added, and the temporary liquid replenishing device supplies liquid to the demineralized and deoxygenated liquid supply device.

[0015] Further, in the step of starting the vacuum pump, at least two vacuum pumps are started.

[0016] Further, before opening the intake valve for detection of the steam turbine, open the union joint structure downstream of the intake valve for detection.

[0017] Further, monitor the liquid level of the liquid drainage container.

[0018] Further, the liquid drainage container is provided with a drain valve. When it is monitored that the liquid level of the liquid drainage container is higher than the preset liquid level, open the drain valve to restore the liquid level of the liquid drainage container to the normal liquid level range.

[0019] Further, close the valve between the liquid drainage container and the condenser to prevent air from entering the condenser through the liquid drainage container.

[0020] Further, a liquid drainage intake valve is provided at the top of the liquid drainage container. When the liquid drainage intake valve is opened, outside air can enter the steam turbine through the liquid drainage container.

[0021] Further, the steam turbine is connected with a temporary intake valve; the temporary intake valve is communicated with the atmosphere through an intake pipeline; when the temporary intake valve is opened, outside air can enter the steam turbine through the intake pipeline.

[0022] The beneficial effects of the sealing detection method for the exhaust valve of the main feed water pump steam turbine of the nuclear power plant provided by this application are as follows: Compared with the prior art, the sealing detection method provided by this application is simple to operate and easy to implement. By steps such as closing the steam inlet valve and the exhaust valve of the steam turbine, injecting liquid into the exhaust valve, monitoring the liquid level of the liquid drainage container, starting the vacuum pump, and opening the intake valve for detection of the steam turbine, and according to the air pressure changes of the first pressure gauge and the second pressure gauge, the sealing performance of the exhaust valve can be accurately judged, thereby effectively avoiding the risk of maintenance work caused by poor sealing of the exhaust valve and improving the operation safety and reliability of the nuclear power plant. Brief Description of the Drawings

[0023] To more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the accompanying drawings required for describing the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a flow diagram of the seal detection method for the exhaust valve of the main feed water pump steam turbine in the nuclear power plant provided by the embodiment of the present application;

[0025] Figure 2 It is a working flow diagram of the seal detection method for the exhaust valve of the main feed water pump steam turbine in the nuclear power plant provided by the embodiment of the present application;

[0026] Figure 3 It is a structural schematic diagram of the seal detection device adopted by the seal detection method for the exhaust valve of the main feed water pump steam turbine in the nuclear power plant provided by the embodiment of the present application.

[0027] Among them, the reference numerals in the figure:

[0028] 1 - Steam turbine;

[0029] 2 - Condenser;

[0030] 3 - Exhaust valve;

[0031] 4 - First pressure gauge;

[0032] 5 - Second pressure gauge;

[0033] 6 - Demineralized and deoxygenated liquid supply device;

[0034] 7 - Liquid drainage container;

[0035] 8 - Steam inlet valve;

[0036] 9 - Water outlet valve;

[0037] 10 - Liquid drainage pump;

[0038] 11 - Intake valve for detection;

[0039] 12 - Temporary intake valve;

[0040] 13 - Liquid drainage intake valve. Detailed implementation manners

[0041] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the following further details the present application in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0042] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0043] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0044] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0045] Please refer to Figure 1 and Figure 3 , and a seal detection method for the exhaust valve of the main feed water pump steam turbine of a nuclear power plant provided in an embodiment of the present application will be described. The seal detection method includes closing the steam inlet valve 8 and the exhaust valve 3 of the steam turbine 1; continuously injecting liquid into the exhaust valve 3; injecting liquid into the liquid drainage container 7 to make the liquid drainage container 7 in a water seal state; starting a vacuum pump to make the condenser 2 in a vacuum state; opening the detection air inlet valve 11 of the steam turbine 1 to allow external air to enter the steam turbine 1; if the pressure value of the first pressure gauge 4 for detecting the internal pressure of the steam turbine 1 is greater than or equal to the first target value, and the pressure value of the second pressure gauge 5 for detecting the internal pressure of the condenser 2 is less than or equal to the second target value, then the sealing performance of the exhaust valve 3 is qualified; otherwise, the sealing performance of the exhaust valve 3 is unqualified.

[0046] Compared with the prior art, the seal detection method for the exhaust valve of the main feed water pump steam turbine provided by the present application is simple to operate and easy to implement. By closing the steam inlet valve and the exhaust valve of the steam turbine, injecting liquid into the exhaust valve, monitoring the liquid level of the liquid drainage container, starting the vacuum pump, opening the detection air inlet valve of the steam turbine, etc., and according to the air pressure changes of the first pressure gauge and the second pressure gauge, the sealing performance of the exhaust valve can be accurately judged, thus effectively avoiding the risk of maintenance work caused by poor sealing of the exhaust valve and improving the operation safety and reliability of the nuclear power plant.

[0047] It is understandable that the seal detection method for the exhaust valve of the main feed water pump steam turbine of the present application adopts a seal detection device. As Figure 3 shown, the seal detection device includes a steam turbine 1, a condenser 2, an exhaust valve 3, a first pressure gauge 4, a second pressure gauge 5, a demineralized and deoxygenated liquid supply device 6, a liquid drainage container 7, and a vacuum pump (not shown); the steam turbine 1 is connected with a plurality of steam inlet valves 8; the condenser 2 is connected with the steam turbine 1 through an exhaust pipeline; the exhaust valve 3 is arranged on the exhaust pipeline; the first pressure gauge 4 is connected with the steam turbine 1, and the first pressure gauge 4 is used to monitor the pressure value inside the steam turbine 1; the second pressure gauge 5 is connected with the condenser 2, and the second pressure gauge 5 is used to monitor the pressure value inside the condenser 2; the demineralized and deoxygenated liquid supply device 6 is connected with the exhaust valve 3; the water inlet of the liquid drainage container 7 is communicated with the steam turbine 1, and the water outlet of the liquid drainage container 7 is communicated with the condenser 2; the vacuum pump is connected with the condenser 2, and the vacuum pump is used to maintain the condenser 2 in a vacuum state.

[0048] The seal detection device provided by the embodiment of the present application has a simple structure and is easy to operate. By setting the first pressure gauge 4 and the second pressure gauge 5, the air pressure changes inside the steam turbine 1 and the condenser 2 are observed to judge the sealing performance of the exhaust valve 3, thereby solving the technical problem in the prior art that the sealing performance of the exhaust valve 3 cannot be detected; by setting the demineralized and deoxygenated liquid supply device 6, the water seal of the exhaust valve 3 can be realized, and by setting the liquid drainage container 7, the water seal of the condenser 2 can be realized, preventing external air from entering the condenser 2 and improving the accuracy of the seal detection of the exhaust valve 3.

[0049] In an embodiment of the present application, the seal detection device further includes a steam inlet pipeline, one end of the steam inlet pipeline is connected with the steam turbine 1, and the other end of the steam inlet pipeline is used to connect to an upstream device; the steam inlet valve 8 is arranged on the steam inlet pipeline.

[0050] In this embodiment, by setting the steam inlet pipeline and the steam inlet valve 8, the steam inlet of the steam turbine 1 can be conveniently controlled, so that when detecting the sealing performance of the exhaust valve 3, the steam turbine 1 can be operated more flexibly, improving the flexibility and accuracy of the detection. In addition, the setting of the steam inlet pipeline also helps to supply steam to the steam turbine 1 when needed, ensuring the normal operation of the steam turbine 1.

[0051] In an embodiment of the present application, liquid is continuously injected into the exhaust valve 3, which is executed by the demineralized and deoxygenated liquid supply device 6.

[0052] In this embodiment, the demineralized and deoxygenated liquid supply device 6 can provide demineralized and deoxygenated water for the exhaust valve. Using demineralized and deoxygenated water can reduce the impurity and oxygen content in the water, avoid corrosion and damage to the exhaust valve 3, and improve the accuracy and reliability of the detection. In addition, using demineralized and deoxygenated water can also avoid generating bubbles during the detection process, affecting the accurate judgment of the sealing performance of the exhaust valve 3.

[0053] In one embodiment of the present application, a water inlet pipe is connected to the desalination and deoxygenation liquid supply device 6, and a water injection valve (not shown) is provided on the water inlet pipe; please refer to Figure 3 , the desalination and deoxygenation liquid supply device 6 is connected to the exhaust valve 3 through a water outlet pipe, and a water outlet valve 9 is provided on the water outlet pipe.

[0054] In this embodiment, by setting the water inlet pipe and the water injection valve, water can be conveniently added to the desalination and deoxygenation liquid supply device 6, providing sufficient water volume for the subsequent sealing detection of the exhaust valve 3. The setting of the water outlet pipe and the water outlet valve 9 can precisely control the water volume injected into the exhaust valve 3, making the water seal effect more ideal and further improving the accuracy of the sealing detection of the exhaust valve 3.

[0055] In one embodiment of the present application, in the step of continuously injecting liquid into the exhaust valve 3, a temporary liquid supplement device is added, and the temporary liquid supplement device supplies liquid to the desalination and deoxygenation liquid supply device 6.

[0056] In this embodiment, the setting of the temporary liquid supplement device can ensure that when the water volume in the desalination and deoxygenation liquid supply device 6 is insufficient, sufficient water volume can be provided to the exhaust valve 3 in a timely manner, ensuring the smooth progress of the sealing detection process. The temporary liquid supplement device can be a water storage tank, which is connected to the desalination and deoxygenation liquid supply device 6 through a pipeline. When liquid supplement is required, the valve on the connecting pipeline is opened to realize liquid supplement to the desalination and deoxygenation liquid supply device 6. Such a design not only ensures the continuity of the sealing detection process but also improves the detection efficiency and accuracy.

[0057] In one embodiment of the present application, the desalination and deoxygenation liquid supply device 6 is also provided with a liquid supplement valve and a liquid supplement pipeline. The liquid supplement valve is arranged on the liquid supplement pipeline. One end of the liquid supplement pipeline is connected to the desalination and deoxygenation liquid supply device 6, and the other end is connected to the exhaust valve 3. During the detection process, if the liquid level of the desalination and deoxygenation liquid supply device 6 drops, the liquid supplement valve can be opened to supplement desalinated and deoxygenated water to the desalination and deoxygenation liquid supply device 6 through the liquid supplement pipeline to ensure continuous injection of liquid into the exhaust valve 3 and ensure the continuity and accuracy of the detection.

[0058] In one embodiment of the present application, in the step of starting the vacuum pump, at least two vacuum pumps are started.

[0059] In this embodiment, the vacuum pump is the air extraction system of the condenser 2, which extracts the non-condensable gas in the condenser 2 to maintain the vacuum of the condenser 2. The nuclear power plant is designed with three vacuum pumps. During normal operation, generally only one vacuum pump is required to maintain the vacuum of the condenser 2. During this test, in order to avoid the possible abnormal increase in the vacuum of the condenser 2, another vacuum pump was started in advance, and the test was carried out after maintaining two vacuum pumps to increase the suction capacity of the vacuum pump.

[0060] Further, after starting the vacuum pump to make the condenser in a vacuum state, continuously monitor the vacuum degree inside the condenser. If the vacuum degree is lower than the preset value, promptly adjust the working state of the vacuum pump or check the sealing performance of the condenser to ensure the accuracy and reliability of the detection process. In addition, during the entire detection process, strictly control the operation time and operation sequence to avoid interfering with the detection results due to improper operation.

[0061] In an embodiment of the present application, before opening the detection intake valve 11 of the steam turbine 1, open the union structure downstream of the detection intake valve 11.

[0062] Specifically, the seal detection device further includes an exhaust branch. One end of the exhaust branch is connected to the exhaust pipeline, and the other end of the exhaust branch is used to connect to the downstream union structure; the detection intake valve 11 is arranged on the exhaust branch; when detecting the sealing performance of the exhaust valve 3, first close the detection intake valve 11, remove the downstream union structure, and then open the detection intake valve 11.

[0063] It can be understood that after the downstream union structure is removed, the outside air can enter the steam turbine 1 from the exhaust branch pipe. To ensure the accuracy of the detection results, before removing the downstream union structure, the detection intake valve 11 needs to be closed first; after removing the downstream union structure, then open the detection intake valve 11 so that the outside air can smoothly enter the steam turbine 1 through the exhaust branch, thereby realizing the accurate detection of the sealing performance of the exhaust valve 3. The setting of the detection intake valve 11 not only ensures the air circulation during the detection process but also can effectively isolate the connection between the exhaust branch and the downstream union structure when not in detection, avoiding unnecessary energy loss and safety hazards.

[0064] In a preferred embodiment of the present application, to improve the detection efficiency, before removing the downstream union structure, the tools and materials required for detection, such as pressure gauges, connecting pipelines, etc., can be prepared in advance to reduce the waiting time during the detection process. At the same time, to ensure the safety of the detection personnel, obvious safety warning signs can be set in the detection area, and necessary safety protection equipment, such as safety helmets, protective glasses, etc., can be equipped.

[0065] In addition, during the detection process, the detection personnel should operate strictly in accordance with the operating procedures to avoid safety accidents caused by misoperation. At the same time, the detection data should be accurately recorded and analyzed to promptly discover and solve problems. After the detection is completed, the detection device should be thoroughly cleaned and disinfected to prevent cross-contamination and corrosion.

[0066] In an embodiment of the present application, monitor the liquid level of the drain liquid container 7.

[0067] In an embodiment of the present application, the liquid level of the liquid drainage container 7 is monitored by a liquid level sensor provided on the liquid drainage container 7. The liquid level sensor can monitor the change of the liquid level in the liquid drainage container 7 in real time and feed the monitoring data back to the control system. When the liquid level is higher than the preset liquid level, the control system will automatically open the drain valve to drain the excess liquid, so that the liquid level of the liquid drainage container 7 returns to the normal liquid level range. Such a design not only ensures the normal operation of the liquid drainage container 7 but also avoids potential safety hazards caused by too high a liquid level.

[0068] Specifically, during the seal detection process, the change of the liquid level in the liquid drainage container 7 can reflect the sealing state of the steam exhaust valve 3. If the steam exhaust valve 3 is poorly sealed, outside air may enter the condenser 2 through the steam exhaust valve 3, resulting in an increase in the internal pressure of the condenser 2. At the same time, due to the entry of air, the liquid in the liquid drainage container 7 may be squeezed, causing a change in the liquid level. Therefore, by monitoring the liquid level of the liquid drainage container 7, the situation of poor sealing of the steam exhaust valve 3 can be detected in a timely manner, improving the accuracy and reliability of the detection.

[0069] In an embodiment of the present application, the liquid drainage container 7 is provided with a drain valve. When it is monitored that the liquid level of the liquid drainage container 7 is higher than the preset liquid level, the drain valve is opened to make the liquid level of the liquid drainage container 7 return to the normal liquid level range.

[0070] In this embodiment, by setting the drain valve, the excess water in the liquid drainage container 7 can be drained in a timely manner, avoiding the influence on the water seal effect caused by too high a liquid level in the liquid drainage container 7. The opening and closing of the drain valve can be automatically controlled according to the liquid level of the liquid drainage container 7 or manually operated, improving the flexibility and reliability of the detection. At the same time, the setting of the preset liquid level can be adjusted according to the actual detection requirements to meet the detection requirements in different situations.

[0071] In an embodiment of the present application, the valve between the liquid drainage container 7 and the condenser 2 is closed to prevent air from entering the condenser 2 through the liquid drainage container 7.

[0072] In this embodiment, when detecting the sealing performance of the steam exhaust valve 3, closing the valve between the liquid drainage container 7 and the condenser 2 can effectively prevent air from entering the condenser 2 through the liquid drainage container 7, thus avoiding the influence of the change of the internal air pressure of the condenser 2 on the detection result and improving the accuracy and reliability of the detection. At the same time, the setting of this valve can also conveniently isolate the liquid drainage container 7 and the condenser 2 after the detection is completed, providing convenience for subsequent operations.

[0073] In an embodiment of the present application, a liquid drainage air inlet valve 13 is provided at the top of the liquid drainage container 7. When the liquid drainage air inlet valve 13 is opened, outside air can enter the steam turbine 1 through the liquid drainage container 7.

[0074] In this embodiment, the liquid drainage inlet valve 13 is arranged on the pipeline connecting the top of the liquid drainage container 7 to the atmosphere. When the liquid drainage inlet valve 13 is opened, the outside air can enter the steam turbine 1 through the liquid drainage container 7, so that the pressure value inside the steam turbine 1 can rise rapidly, further improving the sealing detection efficiency of the exhaust valve 3. Specifically, the number of liquid drainage inlet valves 13 can be set to multiple; for example: in this embodiment, there are three pipelines connecting to the atmosphere, and each pipeline is provided with a liquid drainage inlet valve 13.

[0075] Further, after the step of opening the liquid drainage inlet valve 13 to enable the outside air to enter the steam turbine 1 through the liquid drainage container 7, the following step can also be included: monitoring the change of the internal pressure of the steam turbine 1. If the internal pressure of the steam turbine 1 rises significantly in a short time, it may indicate that there is a leak in the exhaust valve. At this time, the sealing performance of the exhaust valve should be further confirmed. The addition of this step can further improve the accuracy and reliability of the sealing detection, ensuring that the sealing performance of the exhaust valve of the main feed water pump steam turbine 1 in the nuclear power plant meets the safety requirements.

[0076] In an embodiment of the present application, the sealing detection method further includes, after detecting the sealing performance of the exhaust valve 3, closing all the liquid drainage inlet valves 13 to avoid the rapid decrease of the internal pressure of the steam turbine 1 and maintain the accuracy of the detection result. At the same time, open the valve between the liquid drainage container 7 and the condenser 2 to restore the normal operation state of the system. In addition, the method also takes into account safety factors. An emergency shutdown device is provided during the operation. Once an abnormal situation is detected, such as abnormal pressure increase or decrease, the emergency shutdown will be immediately triggered to ensure the safety of the equipment and personnel. The entire sealing detection process has a high degree of automation and is easy to operate, greatly improving the detection efficiency and accuracy.

[0077] In an embodiment of the present application, the steam turbine 1 is connected with a temporary inlet valve 12; the temporary inlet valve 12 is connected to the atmosphere through an intake pipeline; when the temporary inlet valve 12 is opened, the outside air can enter the steam turbine 1 through the intake pipeline.

[0078] In this embodiment, by setting the intake pipeline and the temporary inlet valve 12, the amount of air entering the steam turbine 1 can be further increased, improving the sealing detection efficiency of the exhaust valve 3. At the same time, the setting of the temporary inlet valve 12 can also close the intake pipeline when the sealing detection of the exhaust valve 3 is not required, avoiding the outside air from entering the steam turbine 1 through the intake pipeline, ensuring the normal operation and safety of the steam turbine 1. In addition, the other end of the intake pipeline is connected to the atmosphere, making it convenient to introduce the outside air when detecting the sealing performance of the exhaust valve 3, improving the detection efficiency and accuracy.

[0079] In an embodiment of the present application, the temporary intake valve 12 and the intake pipeline are also provided with a valve controller, which is used to control the opening and closing of the temporary intake valve 12. During the detection process, the opening and closing of the temporary intake valve 12 can be remotely controlled through the valve controller, avoiding the inconvenience and safety hazards brought by manual operation. At the same time, by setting the valve controller, it is also possible to accurately control the opening and closing time of the temporary intake valve 12, improving the accuracy and reliability of the detection.

[0080] In an embodiment of the present application, in order to ensure the smooth progress of the seal detection process, the seal detection device needs to be comprehensively inspected before detection to ensure that all components are intact and tightly connected. In particular, key components such as the exhaust valve, the first pressure gauge 4, the second pressure gauge 5, the demineralization and deoxygenation liquid supply device 6, the liquid drainage container 7, and the vacuum pump need to be confirmed to be in a normal working state to avoid detection errors caused by equipment failures.

[0081] In this embodiment, the detection personnel also need to be familiar with the operation process and safety specifications of the seal detection device to ensure that various operations can be accurately performed during the detection process while ensuring their own safety. During the detection process, it is necessary to closely monitor the changes in the first pressure gauge 4 and the second pressure gauge 5, as well as the liquid level state of the liquid drainage container, and timely adjust the operation parameters to ensure the accuracy and reliability of the detection.

[0082] In addition, after the detection is completed, the seal detection device needs to be thoroughly cleaned and maintained to extend the service life of the equipment and prepare for the next detection. For the problems found during the detection, they need to be promptly recorded and reported so that corresponding repair or replacement measures can be taken to ensure that the sealing performance of the exhaust valve of the main feed water pump steam turbine in the nuclear power plant always remains in good condition.

[0083] In an embodiment of the present application, please refer to Figure 3 , the seal detection device further includes a liquid drainage pump 10, and the liquid drainage pump 10 is arranged on the pipeline connecting the liquid drainage container 7 and the condenser 2.

[0084] In this embodiment, the setting of the liquid drainage pump 10 can accelerate the flow of water in the liquid drainage container 7, enabling the liquid drainage container 7 to better maintain the water seal state and prevent external air from entering the condenser 2. The start and stop of the liquid drainage pump 10 can be automatically controlled according to the vacuum degree of the condenser 2 and the liquid level of the liquid drainage container 7, or can be manually operated, improving the automation degree and flexibility of the detection. At the same time, the adoption of the liquid drainage pump 10 can also reduce the influence of water level fluctuations on the seal detection results, further improving the accuracy and reliability of the detection.

[0085] In this embodiment, the first target value is 970 MPa; the second target value is 100 MPa. Of course, the specific values of the first target value and the second target value can be adjusted according to the actual working conditions and requirements of the exhaust valve of the main feed water pump steam turbine in the nuclear power plant. When implementing the seal detection method of this application, technicians can determine appropriate first and second target values based on experience or experimental data to ensure the accuracy and reliability of the seal detection.

[0086] In addition, it is worth noting that the seal detection method of this application is not only applicable to the seal detection of the exhaust valve of the main feed water pump steam turbine in the nuclear power plant, but also can be applied to the seal detection of other similar equipment and valves. By adopting the seal detection method of this application, the seal performance of the equipment and valves can be effectively improved, and the potential safety hazards and working risks caused by poor sealing can be reduced, thereby improving the operation safety and reliability of the entire system.

[0087] Please refer to Figure 2 , the seal detection method for the exhaust valve of the main feed water pump steam turbine provided by this application specifically includes the following steps:

[0088] Step 1: Isolate the steam side of the steam turbine 1, and close all valves connecting to the steam turbine 1, including the valve between the drain pump 10 and the condenser 2, as well as multiple steam inlet valves 8 and the exhaust valve 3;

[0089] Step 2: Supplement demineralized and deoxygenated water to the demineralized and deoxygenated liquid supply device 6 to ensure the normal liquid level of the demineralized and deoxygenated liquid supply device 6;

[0090] Step 3: Open the water outlet valve 9 of the demineralized and deoxygenated liquid supply device 6, and inject demineralized and deoxygenated water into the exhaust valve 3 to form a water seal state in the exhaust valve 3 to ensure the accuracy of the detection result;

[0091] Step 4: Detect the water level of the drain container 7. When the liquid level of the drain container 7 is higher than the preset liquid level, open the drain valve to restore the liquid level of the drain container 7 to the normal liquid level range;

[0092] Step 5: Open the water injection valve of the drain container 7 to fill the drain container 7 with liquid to the normal water level, establish a water seal, and prevent air from entering the condenser 2 through the drain container 7;

[0093] Step 6: Start the vacuum pump to extract the non-condensable gas in the condenser 2 and maintain the vacuum state of the condenser 2;

[0094] Step 7: Close the intake valve 11 for detection and remove the downstream union structure;

[0095] Step 8: Slowly open the opening on the steam turbine 1 and monitor the pressure values of the first pressure gauge 4 and the second pressure gauge 5; Opening the opening on the steam turbine 1 mainly allows external air to enter the steam turbine 1. Observe whether the internal pressure of the steam turbine 1 is close to the atmospheric pressure through the first pressure gauge 4, and judge whether the pressure of the condenser 2 rises by observing the second pressure gauge 5, so as to judge whether the exhaust valve 3 is tight;

[0096] The opening on the steam turbine 1 includes an intake valve 11 for detection, three drain intake valves 13, and a temporary intake valve 12. When opening the opening on the steam turbine 1, it can be opened in sequence according to the intake valve 11 for detection, the three drain intake valves 13, and the temporary intake valve 12, so that the internal pressure of the steam turbine 1 gradually increases;

[0097] Step 9: Judge that if the pressure value of the second pressure gauge 5 ≤ 100 MPa and the pressure value of the first pressure gauge 4 ≥ 970 MPa, it means that the inside of the steam turbine 1 is close to the atmospheric pressure, and the pressure of the condenser 2 can also be maintained normally, proving that the sealing performance of the exhaust valve 3 is qualified; otherwise, the sealing performance of the exhaust valve 3 is unqualified.

[0098] After judging that the sealing performance of the exhaust valve 3 is qualified, in order to further ensure the accuracy of the detection results, a review step can also be carried out. The review step can include but is not limited to re-detecting the vacuum degree of the condenser 2 to confirm whether it still remains within the preset range, and re-checking the liquid level of the drain container 7 to ensure that there is no abnormal fluctuation. The implementation of these review steps can further enhance the reliability and persuasiveness of the detection results.

[0099] In addition, during the entire sealing detection process, attention should also be paid to data recording and analysis. Each detection data should be recorded in detail, including but not limited to the vacuum degree of the condenser 2, the liquid level of the drain container 7, the pressure values of the first pressure gauge 4 and the second pressure gauge 5, etc. By analyzing these data, potential problems and trends can be discovered in a timely manner, providing a basis for subsequent maintenance and optimization.

[0100] It should be noted that the sealing detection method of the present application not only focuses on the detection results, but also pays attention to the safety and operability of the detection process. During the detection process, a number of safety measures are taken, such as setting up an emergency shutdown device and equipping safety protection equipment to ensure the safety of equipment and personnel. At the same time, the design of the detection method also fully considers the convenience and efficiency in actual operation, enabling the detection personnel to easily get started and quickly complete the detection task.

[0101] In summary, the sealing detection method of the exhaust valve of the main feed water pump steam turbine of the present application has high accuracy, reliability and safety, can effectively evaluate the sealing performance of the exhaust valve, and provides a strong guarantee for the safe operation of the nuclear power plant. At the same time, the detection method also has a high degree of automation and flexibility, and can adapt to the detection requirements under different conditions.

[0102] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A sealing detection method for the exhaust valve of the main feed water pump steam turbine in a nuclear power plant, characterized in that, The described seal detection method includes: Closing the steam inlet valve and the exhaust valve of the steam turbine; Continuously injecting liquid into the exhaust valve; Injecting liquid into the liquid drainage container to make the liquid drainage container in a water seal state; Starting the vacuum pump to make the condenser in a vacuum state; Opening the detection air inlet valve of the steam turbine to allow external air to enter the steam turbine; If the pressure value of the first pressure gauge for detecting the internal pressure of the steam turbine is greater than or equal to the first target value, and the pressure value of the second pressure gauge for detecting the internal pressure of the condenser is less than or equal to the second target value, then the exhaust valve has qualified sealing performance; otherwise, the exhaust valve has unqualified sealing performance.

2. The seal detection method according to claim 1, wherein The continuous injection of liquid into the exhaust valve is performed by the demineralized and deoxidized liquid supply device.

3. The seal detection method according to claim 2, characterized in that, In the step of continuously injecting liquid into the exhaust valve, a temporary liquid supplement device is added, and the temporary liquid supplement device supplies liquid to the demineralized and deoxidized liquid supply device.

4. The sealing detection method according to claim 1, wherein In the step of starting the vacuum pump, at least two vacuum pumps are started.

5. The sealing detection method according to claim 1, characterized in that Before opening the detection air inlet valve of the steam turbine, open the union structure downstream of the detection air inlet valve.

6. The seal detection method according to claim 1, characterized in that, Monitor the liquid level of the liquid drainage container.

7. The seal detection method according to claim 6, wherein, The liquid drainage container is provided with a drain valve. When it is monitored that the liquid level of the liquid drainage container is higher than the preset liquid level, open the drain valve to make the liquid level of the liquid drainage container return to the normal liquid level range.

8. The seal detection method according to claim 1, wherein, Close the valve between the liquid drainage container and the condenser to prevent air from entering the condenser through the liquid drainage container.

9. The sealing detection method according to claim 1, characterized in that The top of the liquid drainage container is provided with a liquid drainage air inlet valve. When the liquid drainage air inlet valve is opened, external air can enter the steam turbine through the liquid drainage container.

10. The sealing detection method according to any one of claims 1-9, characterized in that, The steam turbine is connected with a temporary air inlet valve; the temporary air inlet valve is communicated with the atmosphere through an air inlet pipeline; when the temporary air inlet valve is opened, external air can enter the steam turbine through the air inlet pipeline.

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