A full stroke test method for high temperature gas cooled reactor evaporator accident drain valve
By triggering and closing the emergency discharge valve under shutdown conditions in a high-temperature gas-cooled reactor nuclear power plant, and monitoring the valve status and recording the action time in the DCS, the effectiveness of the full-stroke test of the emergency discharge valve of the high-temperature gas-cooled reactor evaporator was solved, ensuring the safety of the reactor and the stability of the test.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA HUANENG GRP CO LTD
- Filing Date
- 2023-09-27
- Publication Date
- 2026-07-31
AI Technical Summary
How to ensure the effectiveness of the full-stroke test of the emergency discharge valve of the high-temperature gas-cooled reactor evaporator without causing additional impact on the reactor status, and ensure the operability of the reactor's dedicated safety system.
During the shutdown of a high-temperature gas-cooled reactor nuclear power plant, the emergency discharge valve is opened and closed by triggering the SG emergency discharge button in the main control room. Combined with DCS valve status monitoring and full log recording, the effectiveness of the full-stroke test of the emergency discharge valve is ensured, and the evaporator liquid level is restored to the preset value after the test.
This study demonstrates the effectiveness of conducting a full-stroke test of the emergency discharge valve of the high-temperature gas-cooled reactor evaporator under shutdown conditions, avoiding additional impacts on the reactor safety system and ensuring the stability and safety of the test process.
Smart Images
Figure CN117316474B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of high-temperature gas-cooled reactor technology, specifically relating to a full-stroke test method for the emergency discharge valve of a high-temperature gas-cooled reactor evaporator. Background Technology
[0002] The steam generator emergency discharge system is a dedicated safety system related to reactor safety. Because the primary side (shell side) of the high-temperature gas-cooled reactor's once-through steam generator contains helium, while the secondary side (pipe side) contains water and steam, and the pressure on the water and steam sides of the steam generator is higher than that on the helium side, when a heat exchange tube failure occurs, water and steam leak into the primary loop. This water and steam, along with the helium, flows into the reactor, increasing reactivity and raising the primary loop pressure, potentially damaging the reactor core. To ensure reactor safety, the amount of water and steam entering the reactor's primary loop system must be minimized and kept within limits. This requires the steam generator emergency discharge system to open the discharge valves rapidly within 3 seconds. The discharge pipelines are connected in parallel, with each pipeline containing two discharge valves connected in series. This ensures the system can still function even if either valve fails. A manual emergency discharge activation button is installed in the main control room as a backup activation method. Valve testing is performed by operating this emergency discharge button to test the valve's full stroke.
[0003] However, ensuring the operability of the reactor's dedicated safety system without causing additional impact on the reactor's condition after the test has become an urgent technical problem to be solved. Summary of the Invention
[0004] The present invention aims to solve at least one of the technical problems existing in the prior art, and to provide a new technical solution for the full-stroke test method of the emergency discharge valve of a high-temperature gas-cooled reactor evaporator.
[0005] According to one aspect of the present invention, a method for testing the full stroke of an emergency discharge valve in a high-temperature gas-cooled reactor evaporator is provided, comprising the following steps:
[0006] Step S100, Pre-test preparation stage: Confirm that the reactor corresponding to the high-temperature gas-cooled reactor nuclear power plant test is in a shutdown condition; at the same time, the liquid level in the evaporator's emergency discharge tank is 3.4m-3.6m;
[0007] Step S200, Full-stroke test stage: Trigger the SG emergency discharge button on the control panel in the main control room to open the emergency discharge valve. After the emergency discharge valve is fully open, trigger the SG emergency discharge end button to close the emergency discharge valve. Reset the SG emergency discharge button and the SG emergency discharge end button.
[0008] Step S300, Post-test recovery phase: Adjust the liquid level in the evaporator's emergency discharge tank to the preset level.
[0009] Optionally, shutdown conditions include:
[0010] The regulating rods and safety rods are located at the bottom of the reactor. The main helium blower is shut down, the main steam isolation valve is closed, the main feedwater isolation valve is closed, the main feedwater pump is shut down, the primary loop pressure is greater than 1 MPa, and the steam generator pressure is close to atmospheric pressure.
[0011] Optionally, during the preparation phase before the test, the evaporator pressure is released to atmospheric pressure; at the same time, during the process of the evaporator pressure drop, the reactor pressure is released to below 2.5 MPa.
[0012] Optionally, after triggering the SG emergency discharge button on the control panel in the main control room, the DCS valve status is monitored to determine the opening status of the emergency discharge valve.
[0013] Optionally, after triggering the SG emergency discharge end button, the action time of the emergency discharge valve is recorded by querying the valve action information in the DCS full log.
[0014] Optionally, the first output end of the main water supply pipe is connected to the first branch pipe, and the second output end is connected to the second branch pipe. The first branch pipe is equipped with a first emergency discharge valve and a second emergency discharge valve, and the second branch pipe is equipped with a third emergency discharge valve and a fourth emergency discharge valve. The ends of the first branch pipe and the second branch pipe that are away from the main water supply pipe are both connected to an emergency discharge tank.
[0015] During the full-stroke test phase, the fluid in the secondary circuit is discharged sequentially through the main water supply pipe, the first branch pipe, and the second branch pipe into the emergency discharge tank.
[0016] Optionally, the emergency discharge tank is connected to an exhaust pipe, and the exhaust pipe is equipped with an exhaust valve;
[0017] The pressure inside the emergency discharge tank is regulated by the exhaust valve.
[0018] Optionally, a drain pipe is connected to the emergency discharge tank, and a drain valve is installed on the drain pipe;
[0019] During the recovery phase after the test, when the liquid level in the emergency discharge tank is higher than the preset liquid level, the drain valve is opened, and the fluid in the emergency discharge tank flows out through the drain pipe to lower the liquid level in the emergency discharge tank to the preset liquid level.
[0020] Optionally, the SG emergency discharge button includes a first SG emergency discharge button and a second SG emergency discharge button, and the opening of the emergency discharge valve can be controlled by either the first SG emergency discharge button or the second SG emergency discharge button.
[0021] Optionally, triggering an emergency reactor shutdown will cause the high-temperature gas-cooled reactor nuclear power plant to be in a shutdown state;
[0022] Alternatively, the high-temperature gas-cooled reactor nuclear power plant may be put into a shutdown state by performing operations such as tripping the shutdown circuit breaker, tripping the helium blower circuit breaker, closing the main steam isolation valve, and closing the main feedwater isolation valve.
[0023] One technical advantage of this invention is that:
[0024] In the embodiments of this application, under the shutdown condition of a high-temperature gas-cooled reactor nuclear power plant, the full-stroke test method of the high-temperature gas-cooled reactor evaporator emergency discharge valve can effectively ensure the effectiveness of the full-stroke test of the emergency discharge valve of the evaporator emergency discharge system, and can ensure that the test will not cause any additional impact on the reactor safety system. Attached Figure Description
[0025] Figure 1 This is a schematic flowchart of a full-stroke test method for an emergency discharge valve of a high-temperature gas-cooled reactor according to an embodiment of the present invention.
[0026] Figure 2 This is a schematic diagram of the connection relationship of the emergency discharge tank in a full-stroke test method for an emergency discharge valve of a high-temperature gas-cooled reactor evaporator according to another embodiment of the present invention.
[0027] In the diagram: 1. Main water supply pipe; 21. First branch pipe; 22. Second branch pipe; 31. First emergency discharge valve; 32. Second emergency discharge valve; 33. Third emergency discharge valve; 34. Fourth emergency discharge valve; 4. Emergency discharge tank; 5. Exhaust pipe; 6. Exhaust valve; 7. Drain pipe; 8. Drain valve. Detailed Implementation
[0028] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values of the components and steps set forth in these embodiments do not limit the scope of the present application.
[0029] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.
[0030] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.
[0031] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0032] According to one aspect of the present invention, a full-stroke test method for the emergency discharge valve of a high-temperature gas-cooled reactor evaporator is provided, which not only enables the test to be carried out smoothly and effectively, but also does not cause any additional impact on the reactor status after the test, thus ensuring the operability of the reactor's dedicated safety system.
[0033] Specifically, such as Figure 1 As shown, the full-stroke test method for the emergency discharge valve of the high-temperature gas-cooled reactor evaporator includes the following steps:
[0034] Step S100, Pre-test preparation stage: Confirm that the reactor corresponding to the high-temperature gas-cooled reactor nuclear power plant test is in shutdown condition; at the same time, the liquid level in the evaporator's emergency discharge tank is 3.4m-3.6m.
[0035] It should be noted that triggering the SG emergency discharge button on the control panel in the main control room to open the emergency discharge valve will trigger reactor protection actions. Therefore, it is necessary to confirm that the high-temperature gas-cooled reactor nuclear power plant is in a shutdown condition before the test to ensure that the test process is carried out safely and stably.
[0036] Step S200, full-stroke test stage: Trigger the SG emergency discharge button on the control panel in the main control room to open the emergency discharge valve. After the emergency discharge valve is fully open, trigger the SG emergency discharge end button to close the emergency discharge valve to reduce the amount of water discharged. Then, reset the SG emergency discharge button and the SG emergency discharge end button.
[0037] Step S300, Post-test recovery phase: Adjust the liquid level in the evaporator's emergency discharge tank to the preset level.
[0038] It should be noted that after the test, the liquid level in the evaporator's emergency discharge tank should be checked and adjusted to the preset level to avoid affecting the reactor safety system. For example, the liquid level in the emergency discharge tank can be restored to the normal value through on-site manual operation, and the evaporator can be filled with water as needed to ensure that the evaporator is in a water-solid state for standby.
[0039] In the embodiments of this application, under the shutdown condition of a high-temperature gas-cooled reactor nuclear power plant, the full-stroke test method of the high-temperature gas-cooled reactor evaporator emergency discharge valve can effectively ensure the effectiveness of the full-stroke test of the emergency discharge valve of the evaporator emergency discharge system, and can ensure that the test will not cause any additional impact on the reactor safety system.
[0040] Optionally, shutdown conditions include:
[0041] The regulating rods and safety rods are located at the bottom of the reactor. The main helium blower is shut down, the main steam isolation valve is closed, the main feedwater isolation valve is closed, the main feedwater pump is shut down, the primary loop pressure is greater than 1 MPa, and the steam generator pressure is close to atmospheric pressure.
[0042] In the above implementation, confirming the reactor shutdown condition helps to smoothly conduct the full-stroke test of the emergency discharge valve, avoids triggering reactor protection actions during the test, and ensures the stable progress of the test.
[0043] Optionally, during the preparation phase before the test, the evaporator pressure is released to atmospheric pressure; at the same time, during the process of the evaporator pressure drop, the reactor pressure is released to below 2.5 MPa.
[0044] In the above implementation, in the discharge termination logic, the evaporator's emergency discharge valve will automatically close when the pressure difference between the primary loop helium and the secondary loop steam reaches 0.2 MPa. Therefore, in order to prevent the emergency discharge valve from malfunctioning during the test, the evaporator pressure needs to be released to atmospheric pressure in advance.
[0045] In addition, to meet the requirement of preventing reverse pressure on the evaporator, the reactor is depressurized during the pressure drop of the evaporator to release the pressure to below 2.5 MPa, so as to ensure the safety of the reactor and evaporator operation.
[0046] Optionally, after triggering the SG emergency discharge button on the control panel in the main control room, the DCS valve status is monitored to determine the opening status of the emergency discharge valve, thereby ensuring the effectiveness of the test process.
[0047] In the above implementation method, while monitoring the DCS valve status, the on-site power distribution room can also be arranged to monitor the valve status at the same time, so as to promptly operate the power distribution panel on-site to achieve valve closure when the valve cannot be closed normally.
[0048] Optionally, after triggering the SG emergency discharge end button, the action time of the emergency discharge valve is recorded by querying the valve action information in the DCS full log.
[0049] In the above implementation, by querying the valve action information record of the emergency discharge valve in the DCS full log, the action time of the emergency discharge valve can be accurately understood, which helps to understand the full stroke test.
[0050] Optionally, see Figure 2 The first output end of the main water supply pipe 1 is connected to the first branch pipe 21, and the second output end is connected to the second branch pipe 22. The first branch pipe 21 is equipped with a first emergency discharge valve 31 and a second emergency discharge valve 32. The second branch pipe 22 is equipped with a third emergency discharge valve 33 and a fourth emergency discharge valve 34. The ends of the first branch pipe 21 and the second branch pipe 22 that are away from the main water supply pipe 1 are both connected to the emergency discharge tank 4.
[0051] During the full-stroke test phase, the fluid in the secondary circuit is discharged sequentially through the main water supply pipe 1, the first branch pipe 21, and the second branch pipe 22 into the emergency discharge tank 4.
[0052] In the above embodiment, the fluid in the secondary circuit is discharged into the emergency discharge tank 4 through the main water supply pipe 1, the first branch pipe 21, and the second branch pipe 22 in sequence, thereby ensuring the effectiveness of the full-stroke test of the emergency discharge valve.
[0053] Optionally, an exhaust pipe 5 is connected to the emergency discharge tank 4, and an exhaust valve 6 is provided on the exhaust pipe 5;
[0054] The pressure inside the emergency discharge tank 4 is regulated by the exhaust valve 6.
[0055] In the above embodiment, adjusting the pressure inside the emergency discharge tank 4 by means of the exhaust valve 6 helps to ensure the safety of the emergency discharge tank 4 and also helps to ensure the stability of the drainage process through the main water supply pipe.
[0056] Optionally, the emergency discharge tank 4 is connected to a drain pipe 7, and a drain valve 8 is provided on the drain pipe 7;
[0057] During the recovery phase after the test, when the liquid level in the emergency discharge tank 4 is higher than the preset liquid level, the drain valve 8 is opened, and the fluid in the emergency discharge tank 4 flows out through the drain pipe 7 to lower the liquid level in the emergency discharge tank 4 to the preset liquid level.
[0058] In this embodiment, the recovery phase after the test checks the liquid level in the evaporator's emergency discharge tank. For example, the liquid level in the emergency discharge tank can be restored to its normal value manually on-site. Furthermore, an evaporator water filling operation can be performed as needed to ensure the evaporator is in a liquid state for standby. Evaporator water filling is achieved by starting the feedwater pump and opening the main feedwater isolation valve.
[0059] Optionally, the SG emergency discharge button includes a first SG emergency discharge button and a second SG emergency discharge button, and the opening of the emergency discharge valve can be controlled by either the first SG emergency discharge button or the second SG emergency discharge button.
[0060] In the above implementation, the first SG emergency discharge button and the second SG emergency discharge button serve as backups for each other to ensure the effectiveness of triggering the SG emergency discharge button, thereby ensuring the effectiveness of the full-stroke test of the emergency discharge valve.
[0061] Optionally, triggering an emergency reactor shutdown will cause the high-temperature gas-cooled reactor nuclear power plant to be in a shutdown state;
[0062] Alternatively, the high-temperature gas-cooled reactor nuclear power plant may be put into a shutdown state by performing operations such as tripping the shutdown circuit breaker, tripping the helium blower circuit breaker, closing the main steam isolation valve, and closing the main feedwater isolation valve.
[0063] In the above implementation method, it is necessary to confirm that the high-temperature gas-cooled reactor nuclear power plant is in a shutdown condition before the test to ensure the safe and stable conduct of the test. At the same time, using different methods to bring the high-temperature gas-cooled reactor nuclear power plant into a shutdown condition is simple to operate and easy to implement.
[0064] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.
Claims
1. A method for testing the full stroke of an emergency discharge valve in a high-temperature gas-cooled reactor evaporator, characterized in that, Includes the following steps: Step S100, Pre-test preparation stage: Confirm that the reactor corresponding to the high-temperature gas-cooled reactor nuclear power plant test is in a shutdown condition; at the same time, the liquid level in the evaporator's emergency discharge tank is 3.4m-3.6m; Step S200, Full-stroke test stage: Trigger the SG emergency discharge button on the control panel in the main control room to open the emergency discharge valve. After the emergency discharge valve is fully open, trigger the SG emergency discharge end button to close the emergency discharge valve. Reset the SG emergency discharge button and the SG emergency discharge end button. Step S300, Post-test recovery phase: Adjust the liquid level in the evaporator's emergency discharge tank to the preset level.
2. The high temperature gas cooled reactor vaporizer accident drain valve full stroke test method according to claim 1, characterized in that, The shutdown conditions include: The regulating rods and safety rods are located at the bottom of the reactor. The main helium blower is shut down, the main steam isolation valve is closed, the main feedwater isolation valve is closed, the main feedwater pump is shut down, the primary loop pressure is greater than 1 MPa, and the steam generator pressure is close to atmospheric pressure.
3. The high temperature gas cooled reactor vaporizer accident drain valve full stroke test method according to claim 1, characterized in that, During the preparation phase before the test, the pressure of the evaporator was released to atmospheric pressure; at the same time, during the process of the evaporator pressure drop, the reactor pressure was released to below 2.5 MPa.
4. The high temperature gas cooled reactor vaporizer accident drain valve full stroke test method according to claim 1, characterized in that, After triggering the SG emergency discharge button on the control panel in the main control room, monitor the DCS valve status to determine the opening status of the emergency discharge valve.
5. The high temperature gas cooled reactor vaporizer accident drain valve full stroke test method according to claim 1, characterized in that, After the SG emergency discharge end button is triggered, the action time of the emergency discharge valve is recorded by querying the valve action information in the DCS full log.
6. The high temperature gas cooled reactor vaporizer accident drain valve full stroke test method according to claim 1, characterized in that, The first output end of the main water supply pipe is connected to the first branch pipe, and the second output end is connected to the second branch pipe. The first branch pipe is equipped with a first emergency discharge valve and a second emergency discharge valve, and the second branch pipe is equipped with a third emergency discharge valve and a fourth emergency discharge valve. The ends of the first branch pipe and the second branch pipe that are away from the main water supply pipe are both connected to the emergency discharge tank. During the full-stroke test phase, the fluid in the secondary circuit is discharged sequentially through the main water supply pipe, the first branch pipe, and the second branch pipe into the emergency discharge tank.
7. The full-stroke test method for the emergency discharge valve of a high-temperature gas-cooled reactor evaporator according to claim 6, characterized in that, The emergency discharge tank is connected to an exhaust pipe, and an exhaust valve is installed on the exhaust pipe; The pressure inside the emergency discharge tank is regulated by the exhaust valve.
8. The high temperature gas cooled reactor vaporizer accident drain valve full stroke test method according to claim 7, characterized in that, The emergency discharge tank is connected to a drain pipe, and a drain valve is installed on the drain pipe; During the recovery phase after the test, when the liquid level in the emergency discharge tank is higher than the preset liquid level, the drain valve is opened, and the fluid in the emergency discharge tank flows out through the drain pipe to lower the liquid level in the emergency discharge tank to the preset liquid level.
9. The high temperature gas cooled reactor vaporizer accident drain valve full stroke test method according to claim 1, characterized in that, The SG emergency discharge button includes a first SG emergency discharge button and a second SG emergency discharge button. The opening of the emergency discharge valve can be controlled by either the first SG emergency discharge button or the second SG emergency discharge button.
10. The high temperature gas cooled reactor vaporizer accident drain valve full stroke test method according to claim 1, characterized in that, The emergency reactor shutdown was triggered, causing the high-temperature gas-cooled reactor nuclear power plant to be in shutdown condition. Alternatively, the high-temperature gas-cooled reactor nuclear power plant may be put into a shutdown state by performing operations such as tripping the shutdown circuit breaker, tripping the helium blower circuit breaker, closing the main steam isolation valve, and closing the main feedwater isolation valve.