A high temperature gas cooled reactor turbine seal steam system and method of operation

Abstract

The application provides a high-temperature gas cooled reactor turbine shaft seal steam system and an operation method. The high-temperature gas cooled reactor turbine shaft seal steam system comprises an auxiliary steam loop, an auxiliary boiler steam inlet unit, a start-stop reactor water separator steam inlet unit, a main steam loop, a main steam system, a steam supply main pipe, a turbine high-pressure cylinder and a turbine low-pressure cylinder. A first input end of the auxiliary steam loop is connected to the auxiliary boiler steam inlet unit, and a second input end is connected to the start-stop reactor water separator steam inlet unit. An input end of the main steam loop is connected to the main steam system. An output end of the auxiliary steam loop is connected to the steam supply main pipe and forms a first connection point. An output end of the main steam loop is connected to the steam supply main pipe. The application has the technical effect that the design is reasonable, and the high-temperature gas cooled reactor unit shaft seal steam supply is stable and reliable.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature gas-cooled reactor turbine technology, specifically relating to a shaft sealing steam system and its operation method for a high-temperature gas-cooled reactor turbine. Background Technology

[0002] High-temperature gas-cooled reactor (HTGR) units use high-temperature, high-pressure steam to drive turbine generator sets for power generation. However, due to the long start-up and shutdown times and lack of reheat in HTGR units, the steam turbine requires a long time to be supplied by an external shaft seal steam source, and the temperature parameters are critical. Furthermore, any malfunction in the shaft seal system during this period will render the HTGR unit inoperable. Therefore, it is necessary to design a reliable turbine shaft seal steam system and its economical and reasonable operating mode. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art, and to provide a new technical solution for a high-temperature gas-cooled reactor turbine shaft seal steam system and its operation method.

[0004] According to a first aspect of the present invention, a high-temperature gas-cooled reactor turbine shaft seal steam system is provided, comprising:

[0005] The auxiliary steam circuit includes an auxiliary boiler steam supply unit and a start-stop reactor steam-water separator steam supply unit; the first input terminal of the auxiliary steam circuit is connected to the auxiliary boiler steam supply unit, and the second input terminal is connected to the start-stop reactor steam-water separator steam supply unit.

[0006] The main steam circuit and the main steam system, wherein the input terminal of the main steam circuit is connected to the main steam system;

[0007] The system includes a steam supply header, a high-pressure cylinder of the steam turbine, and a low-pressure cylinder of the steam turbine. The output end of the auxiliary steam circuit is connected to the steam supply header to form a first connection point. The output end of the main steam circuit is also connected to the steam supply header. The front shaft seal steam supply branch pipe of the high-pressure cylinder, the rear shaft seal steam supply branch pipe of the high-pressure cylinder, the front shaft seal steam supply branch pipe of the low-pressure cylinder, and the rear shaft seal steam supply branch pipe of the low-pressure cylinder are sequentially connected to the steam supply header. A second connection point is formed between the front shaft seal steam supply branch pipe of the high-pressure cylinder and the steam supply header. A third connection point is formed between the rear shaft seal steam supply branch pipe of the high-pressure cylinder and the steam supply header. The first connection point is located between the second connection point and the third connection point.

[0008] When the reactor starts up, if the pressure of the steam-water separator in the start-up / shutdown system is not greater than 2 MPa, the steam output from the auxiliary boiler steam supply unit enters the steam supply header through the auxiliary steam loop; if the pressure of the steam-water separator in the start-up / shutdown system is greater than 2 MPa, the steam output from the steam-water separator steam supply unit enters the steam supply header through the auxiliary steam loop; if the steam temperature in the reactor's main steam pipeline is greater than 380°C, the steam output from the main steam system enters the steam supply header through the main steam loop.

[0009] Steam in the steam supply header can enter the front shaft seal steam supply branch pipe of the high-pressure cylinder of the steam turbine, the rear shaft seal steam supply branch pipe of the high-pressure cylinder of the steam turbine, and the front shaft seal steam supply branch pipe of the low-pressure cylinder of the steam turbine, and the rear shaft seal steam supply branch pipe of the low-pressure cylinder of the steam turbine to perform shaft sealing on the high-pressure cylinder and the low-pressure cylinder of the steam turbine.

[0010] Optionally, the high-temperature gas-cooled reactor turbine shaft seal steam system also includes a first bypass branch pipe; the auxiliary steam circuit is provided with a steam superheater, a check valve, a first regulating valve and a first isolation valve in sequence along the direction close to the steam supply header;

[0011] The first end of the first bypass branch pipe is connected to the auxiliary steam circuit to form a fourth connection point, which is located between the check valve and the first regulating valve; the second end of the first bypass branch pipe is connected to the auxiliary steam circuit to form a fifth connection point, which is located between the first isolation valve and the steam supply main pipe; a first bypass valve is provided on the first bypass branch pipe.

[0012] Optionally, the auxiliary steam circuit further includes a first drain pipe, one end of which is connected to the first bypass branch pipe to form a sixth connection point, the sixth connection point being located between the first regulating valve and the first isolation valve; a first drain valve is provided on the first drain pipe.

[0013] Optionally, a second isolation valve is provided on the pipeline connecting the first input end of the auxiliary steam circuit to the auxiliary boiler steam supply unit; an auxiliary steam header is provided on the pipeline connecting the second input end of the auxiliary steam circuit to the start-up / shutdown reactor steam-water separator steam supply unit.

[0014] Optionally, the steam supply unit of the start-stop reactor steam-water separator includes a first start-stop reactor steam-water separator steam supply unit and a second start-stop reactor steam-water separator steam supply unit.

[0015] A third isolation valve is installed on the output pipeline of the steam-water separator of the first start-up / shutdown reactor; a fourth isolation valve is installed on the output pipeline of the steam-water separator of the second start-up / shutdown reactor.

[0016] Optionally, the high-temperature gas-cooled reactor turbine shaft seal steam system also includes a first desuperheating unit, a shut-off valve, a warm-up isolation valve, and a second desuperheating unit;

[0017] Both the first desuperheating unit and the shut-off valve are located on the steam supply header, with the first desuperheating unit located between the first connection point and the third connection point, and the shut-off valve located between the first connection point and the second connection point.

[0018] The second desuperheating unit and the warm-pipe isolation valve are installed in the main steam circuit, with the warm-pipe isolation valve located between the second desuperheating unit and the steam supply header.

[0019] Optionally, the high-temperature gas-cooled reactor turbine shaft seal steam system also includes a second drain pipe and a pressure gauge;

[0020] One end of the second drain pipe is connected to the main steam circuit to form a seventh connection point, which is located between the second desuperheating unit and the warm pipe isolation valve; a second drain valve is provided on the second drain pipe.

[0021] The pressure gauge is located between the seventh connection point and the second cooling unit.

[0022] Optionally, the high-temperature gas-cooled reactor turbine shaft seal steam system also includes a second bypass branch pipe; a second regulating valve and a fifth isolation valve are provided on the main steam circuit; the fifth isolation valve is located between the main steam system and the second desuperheating unit, and the second regulating valve is located between the fifth isolation valve and the second desuperheating unit;

[0023] A second bypass valve is provided on the second bypass branch pipe. The two ends of the second bypass branch pipe form an eighth connection point and a ninth connection point with the main steam circuit, respectively. The eighth connection point is located between the main steam system and the fifth isolation valve. The ninth connection point is located between the second regulating valve and the second desuperheating unit.

[0024] According to a second aspect of the present invention, a method for operating a high-temperature gas-cooled reactor turbine shaft seal steam system as described in the first aspect is provided, comprising the following steps:

[0025] When the reactor is started up, if the pressure of the steam-water separator in the start-up / shutdown system is not greater than 2MPa, the steam output from the auxiliary boiler steam unit enters the steam supply header through the auxiliary steam circuit to provide shaft sealing steam for the high-pressure cylinder and low-pressure cylinder of the turbine.

[0026] When the pressure of the steam-water separator in the start-up and shutdown system is greater than 2MPa, the steam output from the steam-water separator steam-water unit enters the steam supply header through the auxiliary steam circuit to provide shaft seal steam for the high-pressure cylinder and low-pressure cylinder of the turbine.

[0027] When the steam temperature in the main steam pipeline of the reactor is greater than 380°C, the steam output from the main steam system enters the steam supply header through the main steam circuit to provide shaft sealing steam for the high-pressure cylinder and low-pressure cylinder of the turbine.

[0028] When the turbine load increases to a preset value, the shaft seals of the high-pressure cylinder and the low-pressure cylinder of the turbine become self-sealing.

[0029] Optionally, in the event of a reactor accident shutdown, the steam output from the main steam system sequentially enters the steam supply header and the front shaft seal steam supply branch pipe of the turbine high-pressure cylinder to provide high-pressure shaft seals for the turbine high-pressure cylinder.

[0030] Optionally, during the process of the steam output from the steam-water separator of the start-stop reactor sealing the high-pressure cylinder and the low-pressure cylinder of the turbine to the self-sealing of the turbine, the auxiliary boiler steam unit realizes hot standby through the first water supply pipe.

[0031] During the self-sealing process of the steam turbine, the steam output from the main steam system is kept in hot standby through the second water supply pipe; at this time, the pressure of the main steam circuit is maintained at 0.3 MPa.

[0032] One technical advantage of this invention is that:

[0033] In this embodiment, the high-temperature gas-cooled reactor turbine shaft seal steam system and operation method combine the process characteristics of the high-temperature gas-cooled reactor secondary loop system. By utilizing the start-up and shutdown steam from the start-up and shutdown unit of the start-up and shutdown steam-water separator, the start-up boiler steam from the auxiliary boiler steam unit, and the main steam from the main steam system as the shaft seal steam source, and by changing the steam supply mode at each stage of unit start-up and shutdown, the shaft seal steam source is ensured to be in a "one-use, multiple-standby" mode, making the turbine shaft seal system more reliable. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of a high-temperature gas-cooled reactor turbine shaft seal steam system according to an embodiment of the present invention.

[0035] In the diagram: 1. Auxiliary steam circuit; 2. Auxiliary boiler steam supply unit; 31. Steam supply unit for the first start-up / shutdown reactor steam-water separator; 32. Steam supply unit for the second start-up / shutdown reactor steam-water separator; 4. Main steam circuit; 5. Main steam system; 6. Steam supply header; 7. High-pressure turbine cylinder; 71. Front shaft seal steam supply branch pipe for the high-pressure turbine cylinder; 72. Rear shaft seal steam supply branch pipe for the high-pressure turbine cylinder; 8. Low-pressure turbine cylinder; 81. Front shaft seal steam supply branch pipe for the low-pressure turbine cylinder; 82. Rear shaft seal steam supply branch pipe for the low-pressure turbine cylinder; 91. First connection point; 92. Second connection point; 93. Third connection point; 94. Fourth connection point; 95. Fifth connection point; 96. Sixth connection point; 97. 7. Connection point; 98. Connection point 8; 99. Connection point 9; 10. First bypass branch pipe; 11. Steam superheater; 12. Check valve; 13. First regulating valve; 14. First isolation valve; 15. First bypass valve; 16. First drain pipe; 17. First drain valve; 18. Second isolation valve; 19. Auxiliary steam header; 20. Third isolation valve; 21. Fourth isolation valve; 22. First desuperheating unit; 23. Shut-off valve; 24. Warm-up isolation valve; 25. Second desuperheating unit; 26. Second drain pipe; 27. Pressure gauge; 28. Second drain valve; 29. ​​Second bypass branch pipe; 30. Second regulating valve; 311. Fifth isolation valve; 321. Second bypass valve. Detailed Implementation

[0036] 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.

[0037] 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.

[0038] 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.

[0039] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0040] 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.

[0041] According to a first aspect of the invention, see Figure 1 This paper presents a shaft sealing steam system for a high-temperature gas-cooled reactor turbine, which is suitable for the operating characteristics of high-temperature gas-cooled reactor units.

[0042] Specifically, the high-temperature gas-cooled reactor turbine shaft sealing steam system includes:

[0043] The auxiliary steam circuit 1, the auxiliary boiler steam supply unit 2, and the start-stop reactor steam-water separator steam supply unit are provided; the first input terminal of the auxiliary steam circuit 1 is connected to the auxiliary boiler steam supply unit 2, and the second input terminal is connected to the start-stop reactor steam-water separator steam supply unit.

[0044] The main steam circuit 4 and the main steam system 5 are connected, with the input end of the main steam circuit 4 connected to the main steam system 5.

[0045] The steam supply main pipe 6, the high-pressure cylinder 7 of the steam turbine, and the low-pressure cylinder 8 of the steam turbine are connected together. The output end of the auxiliary steam circuit 1 is connected to the steam supply main pipe 6 to form a first connection point 91. The output end of the main steam circuit 4 is connected to the steam supply main pipe 6. The front shaft seal steam supply branch pipe 71, the rear shaft seal steam supply branch pipe 72, the front shaft seal steam supply branch pipe 81, and the rear shaft seal steam supply branch pipe 82 of the low-pressure cylinder of the steam turbine are sequentially connected to the steam supply main pipe 6. The front shaft seal steam supply branch pipe 71 of the high-pressure cylinder and the steam supply main pipe 6 form a second connection point 92, and the rear shaft seal steam supply branch pipe 72 of the high-pressure cylinder and the steam supply main pipe 6 form a third connection point 93. The first connection point 91 is located between the second connection point 92 and the third connection point 93.

[0046] When the reactor starts up, if the pressure of the steam-water separator in the start-up / shutdown system is not greater than 2 MPa, the steam output from the auxiliary boiler steam supply unit 2 enters the steam supply header 6 through the auxiliary steam loop 1; if the pressure of the steam-water separator in the start-up / shutdown system is greater than 2 MPa, the steam output from the steam supply unit of the start-up / shutdown steam-water separator enters the steam supply header 6 through the auxiliary steam loop 1; if the steam temperature of the main steam pipeline of the reactor is greater than 380°C, the steam output from the main steam system 5 enters the steam supply header 6 through the main steam loop 4.

[0047] Steam in the steam supply header 6 can enter the front shaft seal steam supply branch pipe 71 of the high-pressure cylinder of the steam turbine, the rear shaft seal steam supply branch pipe 72 of the high-pressure cylinder of the steam turbine, and the front shaft seal steam supply branch pipe 81 and the rear shaft seal steam supply branch pipe 82 of the low-pressure cylinder of the steam turbine to seal the high-pressure cylinder 7 and the low-pressure cylinder 8 of the steam turbine.

[0048] In this embodiment, the high-temperature gas-cooled reactor turbine shaft seal steam system combines the process characteristics of the high-temperature gas-cooled reactor secondary loop system. It utilizes the start-up and shutdown steam from the start-up and shutdown unit of the start-up and shutdown steam-water separator, the start-up boiler steam from the auxiliary boiler steam unit 2, and the main steam from the main steam system 5 as the shaft seal steam source. By changing the steam supply method at each stage of unit start-up and shutdown, it ensures that the shaft seal steam source is in a "one-use, multiple-standby" mode, making the turbine shaft seal system more reliable.

[0049] In practical applications, the steam source for the turbine shaft seal can be selected according to specific circumstances. The operation is simple and also makes the turbine shaft seal system more reliable.

[0050] Optionally, the high-temperature gas-cooled reactor turbine shaft sealing steam system also includes a first bypass branch pipe 10, which makes the operation of the auxiliary steam circuit 1 more reliable. The auxiliary steam circuit 1 is sequentially equipped with a steam superheater 11, a check valve 12, a first regulating valve 13, and a first isolation valve 14 along the direction close to the steam supply header 6. The first regulating valve 13 is used to regulate the steam flow rate in the auxiliary steam circuit 1 to ensure the shaft sealing effect of the turbine, and its operation is simple. The first isolation valve 14 is used to open or close the auxiliary steam circuit 1.

[0051] The first end of the first bypass branch pipe 10 is connected to the auxiliary steam circuit 1 to form a fourth connection point 94, which is located between the check valve 12 and the first regulating valve 13; the second end of the first bypass branch pipe 10 is connected to the auxiliary steam circuit 1 to form a fifth connection point 95, which is located between the first isolation valve 14 and the steam supply main pipe 6; a first bypass valve 15 is provided on the first bypass branch pipe 10.

[0052] In the above embodiment, before the pressure of the steam-water separator of the first reactor is greater than 2MPa after startup, the auxiliary boiler steam supply unit 2 is used to supply steam. The steam output from the auxiliary boiler steam supply unit 2 is heated by the steam superheater 11 and then enters the front shaft seal steam supply branch pipe 71 of the high-pressure cylinder of the steam turbine, the rear shaft seal steam supply branch pipe 72 of the high-pressure cylinder of the steam turbine, the front shaft seal steam supply branch pipe 81 of the low-pressure cylinder of the steam turbine, and the rear shaft seal steam supply branch pipe 82 of the low-pressure cylinder of the steam turbine, so as to ensure the shaft seal effect of the high-pressure cylinder 7 and the low-pressure cylinder 8 of the steam turbine.

[0053] Optionally, the auxiliary steam circuit 1 further includes a first drain pipe 16, one end of which is connected to the first bypass branch pipe 10 to form a sixth connection point 96, which is located between the first regulating valve 13 and the first isolation valve 14; a first drain valve 17 is provided on the first drain pipe 16. The first drain pipe 16 helps to achieve hot standby of steam supply for the auxiliary steam circuit 1.

[0054] In the above embodiment, during reactor startup, when the steam temperature of the main steam system 5 exceeds 380°C, the steam source for the turbine shaft seal steam system is switched from the auxiliary steam circuit 1 to the main steam circuit 4. At this time, the first isolation valve 14 and the first bypass valve 15 are closed, while the check valve 12, the first regulating valve 13, and the first drain valve 17 remain open. This ensures that the circuits of the steam-water separator supply unit and the auxiliary boiler supply unit 2 are in a warm-up standby state, so that usable steam can be provided to the turbine shaft seal system in a timely manner in case of an accident.

[0055] Optionally, a second isolation valve 18 is installed on the pipeline connecting the first input end of the auxiliary steam circuit 1 to the auxiliary boiler steam supply unit 2; an auxiliary steam header 19 is installed on the pipeline connecting the second input end of the auxiliary steam circuit 1 to the start-up / shutdown reactor steam-water separator steam supply unit. The main function of the auxiliary steam header 19 is to provide a stable steam supply during heating and steam operations, and to ensure stable steam temperature and pressure.

[0056] In the above embodiment, when the pressure of the steam-water separator in the reactor start-up / shutdown system exceeds 2 MPa, the reactor start-up / shutdown system is connected to the auxiliary steam header 19. The steam output from the steam-water separator unit of the reactor start-up / shutdown system is heated by the steam superheater 11 and then enters the turbine, thereby achieving shaft sealing of the high-pressure cylinder 7 and the low-pressure cylinder 8 of the turbine. At this time, the auxiliary boiler steam unit 2 is placed in a lower power or hot standby condition.

[0057] Optionally, the steam supply unit of the start-stop reactor steam separator includes a first start-stop reactor steam separator steam supply unit 31 and a second start-stop reactor steam separator steam supply unit 32.

[0058] A third isolation valve 20 is installed on the output pipeline of the steam supply unit 31 of the first start-up / shutdown reactor steam-water separator; a fourth isolation valve 21 is installed on the output pipeline of the steam supply unit 32 of the second start-up / shutdown reactor steam-water separator.

[0059] In the above embodiment, the first start-up / shutdown steam separator steam supply unit 31 is connected to the first reactor, and the second start-up / shutdown steam separator steam supply unit 32 is connected to the second reactor. During the start-up or shutdown of the two reactors, the first start-up / shutdown steam separator steam supply unit 31 and the second start-up / shutdown steam separator steam supply unit 32 can provide shaft sealing steam to the high-pressure cylinder 7 and the low-pressure cylinder 8 of the turbine, making the turbine shaft sealing process safer and more reliable.

[0060] Optionally, the high-temperature gas-cooled reactor turbine shaft seal steam system also includes a first desuperheating unit 22, a shut-off valve 23, a warm-up isolation valve 24, and a second desuperheating unit 25;

[0061] The first desuperheating unit 22 and the shut-off valve 23 are both located on the steam supply header 6, with the first desuperheating unit 22 located between the first connection point 91 and the third connection point 93, and the shut-off valve 23 located between the first connection point 91 and the second connection point 92.

[0062] The second desuperheating unit 25 and the warm-pipe isolation valve 24 are disposed in the main steam circuit 4, and the warm-pipe isolation valve 24 is located between the second desuperheating unit 25 and the steam supply header 6.

[0063] In the above embodiments, to mitigate the damage to the turbine caused by the loss of turbine shaft seal steam source during dual-reactor shutdown, a shut-off valve 23 is installed in the high- and intermediate-pressure shaft seal circuit (i.e., between the first connection point 91 and the second connection point 92). Closing the shut-off valve 23 reduces the possibility of cold air entering the high-temperature section of the turbine. Simultaneously, a warm-pipe isolation valve 24 is installed on the main steam circuit 4 to supply high-temperature steam, ensuring that the shaft seal steam supplied by the main steam system 5 is in a warmable state, thus guaranteeing the safety and stability of the turbine shaft seal.

[0064] Optionally, the high-temperature gas-cooled reactor turbine shaft seal steam system also includes a second drain pipe 26 and a pressure gauge 27;

[0065] One end of the second drain pipe 26 is connected to the main steam circuit 4 to form a seventh connection point 97, which is located between the second desuperheating unit 25 and the warm pipe isolation valve 24; a second drain valve 28 is provided on the second drain pipe 26.

[0066] The pressure gauge 27 is located between the seventh connection point 97 and the second cooling unit 25.

[0067] In the above embodiment, as the load increases, the turbine can achieve self-sealing when the turbine load reaches a preset value. At this time, by closing the warm-up isolation valve 24, the main steam system 5 circuit is warmed up for standby, the second drain valve 28 is kept open, and the pressure in the pipeline is controlled at approximately 0.3 MPa by setting the pressure gauge 27. To prevent overpressure in the main steam system 5 circuit, the fifth isolation valve 311 and the second bypass valve 321 are equipped with overpressure protection. When the pressure exceeds 0.8 MPa, the fifth isolation valve 311 and the second bypass valve 321 are closed to ensure the safety of the main steam system 5 circuit.

[0068] Optionally, the high-temperature gas-cooled reactor turbine shaft seal steam system also includes a second bypass branch pipe 29; a second regulating valve 30 and a fifth isolation valve 311 are provided on the main steam circuit 4; the fifth isolation valve 311 is located between the main steam system 5 and the second desuperheating unit 25, and the second regulating valve 30 is located between the fifth isolation valve 311 and the second desuperheating unit 25;

[0069] A second bypass valve 321 is provided on the second bypass branch pipe 29. The two ends of the second bypass branch pipe 29 form an eighth connection point 98 and a ninth connection point 99 with the main steam circuit 4, respectively. The eighth connection point 98 is located between the main steam system 5 and the fifth isolation valve 311; the ninth connection point 99 is located between the second regulating valve 30 and the second desuperheating unit 25.

[0070] In the above embodiments, the second bypass branch pipe 29 makes the use of the main steam circuit 4 safer and more reliable, and helps the user to choose to open the main steam circuit 4 or the second bypass branch pipe 29 as needed.

[0071] According to a second aspect of the present invention, a method for operating a high-temperature gas-cooled reactor turbine shaft seal steam system as described in the first aspect is provided, comprising the following steps:

[0072] When the reactor is started up, when the pressure of the steam-water separator in the start-up and shutdown system is not greater than 2MPa, the steam output from the auxiliary boiler steam unit 2 enters the steam supply header 6 through the auxiliary steam circuit 1 to provide shaft sealing steam for the high-pressure cylinder 7 and the low-pressure cylinder 8 of the turbine.

[0073] When the pressure of the steam-water separator in the start-up and shutdown system is greater than 2MPa, the steam output from the steam-water separator steam-water unit enters the steam supply header 6 through the auxiliary steam circuit 1 to provide shaft sealing steam for the high-pressure cylinder 7 and the low-pressure cylinder 8 of the turbine.

[0074] When the steam temperature in the main steam pipeline of the reactor is greater than 380°C, the steam output from the main steam system 5 enters the steam supply header 6 through the main steam circuit 4 to provide shaft sealing steam for the high-pressure cylinder 7 and the low-pressure cylinder 8 of the turbine.

[0075] When the turbine load increases to the preset value, the shaft seals of the high-pressure cylinder 7 and the low-pressure cylinder 8 of the turbine become self-sealing.

[0076] In the above embodiments, the operation mode of the high-temperature gas-cooled reactor turbine shaft seal steam system can be combined with the process characteristics of the high-temperature gas-cooled reactor secondary loop system. By utilizing the start-up and shutdown steam from the start-up and shutdown unit of the start-up and shutdown steam-water separator, the start-up boiler steam from the auxiliary boiler steam unit 2, and the main steam from the main steam system 5 as the shaft seal steam source, and by changing the steam supply mode at each stage of unit start-up and shutdown, the shaft seal steam source is ensured to be in a "one-use, multiple-standby" mode, making the turbine shaft seal system more reliable.

[0077] Optionally, in the event of a reactor accident shutdown, the steam output from the main steam system 5 sequentially enters the steam supply header 6 and the front shaft seal steam supply branch pipe 71 of the turbine high-pressure cylinder to provide high-pressure shaft seals for the turbine high-pressure cylinder 7. This effectively prevents the possibility of cold air entering the high-temperature section of the turbine, ensuring the safety and stability of the turbine operation and better protecting the turbine.

[0078] It should be noted that during reactor shutdown, the steam supply mode for each shaft seal of the turbine is the reverse of the startup process. That is, self-sealing → steam supply from main steam system 5 → steam supply from the start-up / shutdown steam-water separator unit → steam supply from auxiliary boiler steam unit 2.

[0079] During the process of steam output from the steam-water separator unit of the start-up and shutdown reactor sealing the high-pressure cylinder and low-pressure cylinder of the turbine to the self-sealing of the turbine, the auxiliary boiler steam unit achieves hot standby through the first water supply pipe.

[0080] Optionally, during the turbine self-sealing process, the steam output from the main steam system is kept in hot standby through the second water supply pipe; at this time, the pressure of the main steam circuit is maintained at 0.3 MPa.

[0081] In the above embodiments, the multiple shaft seal steam lines serve as backups for each other, which can fully ensure the safety and stability of the turbine shaft seal status, effectively prevent the high-temperature gas-cooled reactor unit from failing to operate due to abnormality of a certain shaft seal steam line, and help ensure the safe and stable operation of the high-temperature gas-cooled reactor.

[0082] In one specific implementation, the high-temperature gas-cooled reactor shutdown or operation signal is taken. In automatic mode, if the shutdown signal of both reactors is detected, the shut-off valve 23 is closed, and the residual steam of the main steam system 5 is supplied only to the highest temperature high-pressure shaft seal (i.e., the front shaft seal steam supply branch pipe 71 of the turbine high-pressure cylinder) to prevent cold gas from entering and causing damage to the turbine.

[0083] Therefore, in this embodiment, the high-temperature gas-cooled reactor turbine shaft sealing steam system and its operation method make the high-temperature gas-cooled reactor turbine shaft sealing steam supply more stable and reliable. Furthermore, in the event of an accident, it can mitigate the hazards caused by the loss of shaft sealing steam.

[0084] 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 high temperature gas cooled pebble bed reactor turbine seal steam system, characterized by, include: The auxiliary steam circuit includes an auxiliary boiler steam supply unit and a start-stop reactor steam-water separator steam supply unit; the first input terminal of the auxiliary steam circuit is connected to the auxiliary boiler steam supply unit, and the second input terminal is connected to the start-stop reactor steam-water separator steam supply unit. The main steam circuit and the main steam system, wherein the input terminal of the main steam circuit is connected to the main steam system; The system includes a steam supply header, a high-pressure cylinder of the steam turbine, and a low-pressure cylinder of the steam turbine. The output end of the auxiliary steam circuit is connected to the steam supply header to form a first connection point. The output end of the main steam circuit is also connected to the steam supply header. The front shaft seal steam supply branch pipe of the high-pressure cylinder, the rear shaft seal steam supply branch pipe of the high-pressure cylinder, the front shaft seal steam supply branch pipe of the low-pressure cylinder, and the rear shaft seal steam supply branch pipe of the low-pressure cylinder are sequentially connected to the steam supply header. A second connection point is formed between the front shaft seal steam supply branch pipe of the high-pressure cylinder and the steam supply header. A third connection point is formed between the rear shaft seal steam supply branch pipe of the high-pressure cylinder and the steam supply header. The first connection point is located between the second connection point and the third connection point. When the reactor starts up, if the pressure of the steam-water separator in the start-up / shutdown system is not greater than 2 MPa, the steam output from the auxiliary boiler steam supply unit enters the steam supply header through the auxiliary steam loop; if the pressure of the steam-water separator in the start-up / shutdown system is greater than 2 MPa, the steam output from the steam-water separator steam supply unit enters the steam supply header through the auxiliary steam loop; if the steam temperature in the reactor's main steam pipeline is greater than 380°C, the steam output from the main steam system enters the steam supply header through the main steam loop. Steam from the steam supply header enters the front shaft seal steam supply branch pipe of the high-pressure cylinder of the steam turbine, the rear shaft seal steam supply branch pipe of the high-pressure cylinder of the steam turbine, the front shaft seal steam supply branch pipe of the low-pressure cylinder of the steam turbine, and the rear shaft seal steam supply branch pipe of the low-pressure cylinder of the steam turbine to seal the high-pressure cylinder and the low-pressure cylinder of the steam turbine.

2. The high temperature gas cooled reactor turbine seal steam system of claim 1, wherein, It also includes a first bypass branch pipe; the auxiliary steam circuit is provided with a steam superheater, a check valve, a first regulating valve and a first isolation valve in sequence along the direction close to the steam supply main pipe; The first end of the first bypass branch pipe is connected to the auxiliary steam circuit to form a fourth connection point, which is located between the check valve and the first regulating valve; the second end of the first bypass branch pipe is connected to the auxiliary steam circuit to form a fifth connection point, which is located between the first isolation valve and the steam supply main pipe; a first bypass valve is provided on the first bypass branch pipe.

3. The high-temperature gas-cooled reactor turbine shaft seal steam system according to claim 2, characterized in that, The auxiliary steam circuit also includes a first drain pipe, one end of which is connected to the first bypass branch pipe to form a sixth connection point, which is located between the first regulating valve and the first isolation valve; a first drain valve is provided on the first drain pipe.

4. The high-temperature gas-cooled reactor turbine shaft seal steam system according to claim 3, characterized in that, A second isolation valve is installed on the pipeline connecting the first input end of the auxiliary steam circuit to the auxiliary boiler steam supply unit; an auxiliary steam header is installed on the pipeline connecting the second input end of the auxiliary steam circuit to the start-stop reactor steam-water separator steam supply unit.

5. The high-temperature gas-cooled reactor turbine shaft seal steam system according to claim 4, characterized in that, The steam supply unit for the start-stop reactor steam-water separator includes a first start-stop reactor steam-water separator steam supply unit and a second start-stop reactor steam-water separator steam supply unit. A third isolation valve is installed on the output pipeline of the steam-water separator of the first start-up / shutdown reactor; a fourth isolation valve is installed on the output pipeline of the steam-water separator of the second start-up / shutdown reactor.

6. The high-temperature gas-cooled reactor turbine shaft seal steam system according to claim 5, characterized in that, It also includes a first deheating unit, a shut-off valve, a warm pipe isolation valve, and a second deheating unit; Both the first desuperheating unit and the shut-off valve are located on the steam supply header, with the first desuperheating unit located between the first connection point and the third connection point, and the shut-off valve located between the first connection point and the second connection point. The second desuperheating unit and the warm-pipe isolation valve are installed in the main steam circuit, with the warm-pipe isolation valve located between the second desuperheating unit and the steam supply header.

7. The high-temperature gas-cooled reactor turbine shaft seal steam system according to claim 6, characterized in that, It also includes a second drain pipe and a pressure gauge; One end of the second drain pipe is connected to the main steam circuit to form a seventh connection point, which is located between the second desuperheating unit and the warm pipe isolation valve; a second drain valve is provided on the second drain pipe. The pressure gauge is located between the seventh connection point and the second cooling unit.

8. The high-temperature gas-cooled reactor turbine shaft seal steam system according to claim 7, characterized in that, It also includes a second bypass branch pipe; a second regulating valve and a fifth isolation valve are provided on the main steam circuit; the fifth isolation valve is located between the main steam system and the second desuperheating unit, and the second regulating valve is located between the fifth isolation valve and the second desuperheating unit; A second bypass valve is provided on the second bypass branch pipe. The two ends of the second bypass branch pipe form an eighth connection point and a ninth connection point with the main steam circuit, respectively. The eighth connection point is located between the main steam system and the fifth isolation valve. The ninth connection point is located between the second regulating valve and the second desuperheating unit.

9. A method for operating the shaft seal steam system of a high-temperature gas-cooled reactor turbine as described in any one of claims 1 to 8, characterized in that, Includes the following steps: When the reactor is started up, if the pressure of the steam-water separator in the start-up / shutdown system is not greater than 2MPa, the steam output from the auxiliary boiler steam unit enters the steam supply header through the auxiliary steam circuit to provide shaft sealing steam for the high-pressure cylinder and low-pressure cylinder of the turbine. When the pressure of the steam-water separator in the start-up and shutdown system is greater than 2MPa, the steam output from the steam-water separator steam-water unit enters the steam supply header through the auxiliary steam circuit to provide shaft seal steam for the high-pressure cylinder and low-pressure cylinder of the turbine. When the steam temperature in the main steam pipeline of the reactor is greater than 380°C, the steam output from the main steam system enters the steam supply header through the main steam circuit to provide shaft sealing steam for the high-pressure cylinder and low-pressure cylinder of the turbine. When the turbine load increases to a preset value, the shaft seals of the high-pressure cylinder and the low-pressure cylinder of the turbine become self-sealing.

10. The operating method according to claim 9, characterized in that, In the event of a reactor accident shutdown, the steam output from the main steam system sequentially enters the steam supply header and the front shaft seal steam supply branch pipe of the turbine high-pressure cylinder to provide high-pressure shaft seals for the turbine high-pressure cylinder.

11. The operating method according to claim 9, characterized in that, During the process of steam output from the steam-water separator unit of the start-up and shutdown reactor sealing the high-pressure cylinder and low-pressure cylinder of the turbine to the self-sealing of the turbine, the auxiliary boiler steam unit achieves hot standby through the first water supply pipe. During the self-sealing process of the steam turbine, the steam output from the main steam system is kept in hot standby through the second water supply pipe; at this time, the pressure of the main steam circuit is maintained at 0.3 MPa.

Images