An on-line test device for a pilot-operated safety valve of a nuclear power plant

Abstract

The present invention belongs to the technical field of pilot-operated safety valves, and particularly relates to an on-line test device for a pilot-operated safety valve in a nuclear power plant. The present invention includes a new connecting bolt, a locking nut, a needle valve, and a quick connector; a through hole is opened in the center of the head of the new connecting bolt, the needle valve is inserted from the head of the new connecting bolt, a locking nut is provided on the upper end surface of the new connecting bolt, and the insertion depth of the needle valve is adjusted through the locking nut; the quick connector is connected to the top of the needle valve. The present invention can realize the on-line switching operation and isolation mode between the pulse pipeline of the pilot-operated safety valve and the control cabinet without isolating and emptying the RRA system.

Description

Technical Field

[0001] The invention belongs to the technical field of pilot-operated safety valves, and particularly relates to an on-line test device for a pilot-operated safety valve in a nuclear power plant. Background Art

[0002] The RRA residual heat removal safety valve used in M310 and its improved units is a SEBIM cold-state pilot-operated safety valve. According to the requirements of the "Regular Test Supervision Outline for Safety-Related Systems and Equipment", the setting pressure test period of the RRA safety valve is one refueling cycle and is implemented during each refueling outage. The pressure setting test of this pilot-operated safety valve is carried out by providing pressure through an external test bench. Due to the special structure of the pilot control cabinet, the connection between the impulse pipeline and the control cabinet must be disconnected when implementing the pressure setting work. Since the impulse pipeline is directly connected to the main pipe of the RRA system, the connected main pipe must be isolated and emptied before the test can be carried out for the pressure setting work; in addition, since the M310 unit is only designed with one train of two groups of RRA pilot-operated safety valves, when the upstream and downstream isolation valves are closed, the RRA system will become unavailable. According to the requirements of the "Operation Technical Specification", the RRA system only has no requirements for functions in the RCD mode. Therefore, for these two reasons, the setting pressure test work of the SEBIM safety valve of the RRA system of the Chinese nuclear power M310 unit is arranged to be carried out in the low-low water level window. If the pressure setting check work of the SEBIM safety valve of the RRA system can be carried out without the low-low water level, the valve maintenance items in the low-low water level window can be reduced, the maintenance time in the low-low water level can be shortened, and conditions can be created for realizing Class D refueling outages without the low-low water level. Therefore, it is necessary to provide an on-line test device for a pilot-operated safety valve in a nuclear power plant so that the pilot-operated safety valve of the RRA system can perform pressure setting work online.

[0003] The introduction of the on-line test device can realize the online isolation of the control cabinet alone by switching to the on-line setting mode without disconnecting the connection between the impulse pipeline and the control cabinet. Thus, the pressure setting work of the RRA pilot-operated safety valve can be carried out without being restricted by the system state and does not occupy the low-low water level window during the refueling outage. Secondly, when the RRA system is running, the on-line test device can meet the normal operation requirements of the RRA pilot-operated safety valve by switching to the operation mode, ensuring the realization of the safety function. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an on-line test device for a pilot-operated safety valve in a nuclear power plant, which can realize the online switching operation and isolation mode between the impulse pipeline of the pilot-operated safety valve and the control cabinet without isolating and emptying the RRA system.

[0005] The technical solution adopted by the present invention:

[0006] An on-line test device for a pilot-operated safety valve in a nuclear power plant, comprising a new connecting bolt, a locking nut, a needle valve, and a quick connector; a through hole is opened from the head at the center of the new connecting bolt, the needle valve is inserted from the head of the new connecting bolt, a locking nut is provided on the upper end surface of the new connecting bolt, and the insertion depth of the needle valve is adjusted by the locking nut; the quick connector is connected to the top of the needle valve.

[0007] Three through holes with different diameters are opened from the head at the center of the new connecting bolt. The first through hole is located at the head of the new connecting bolt, and its length is less than the height of the head. Internal threads are provided on the inner wall of the first through hole; the second through hole is connected to the first through hole, and its diameter is smaller than that of the first through hole. The second through hole extends into the rod part of the new connecting bolt, and its height is located at the middle position of the rod part; the third through hole is connected to the second through hole, and its diameter is smaller than that of the second through hole.

[0008] The needle valve is a stepped shaft. The diameter of the first shaft is the same as the diameter of the second through hole of the new connecting bolt, and its length is less than the height of the second through hole; external threads are provided on the outside of the second diameter shaft, which are matched with the internal threads of the first through hole of the new connecting bolt, and its length is greater than the height of the first through hole; the diameter of the third shaft is greater than the diameter of the first through hole of the new connecting bolt; the fourth shaft is a conical structure, and external threads are provided on its outer wall.

[0009] The quick connector is a two-shaft structure. A groove is opened inside the lower shaft, and internal threads are provided on the inner wall of the groove, which are connected with the external threads of the fourth shaft of the needle valve.

[0010] A through hole is opened at the central position of the needle valve.

[0011] A ring groove is opened on the outer wall of the first shaft, and an O-ring II is installed in the ring groove to ensure the seal between the first shaft and the second through hole through the O-ring II.

[0012] A ring groove is opened on the outer wall of the rod part of the new connecting bolt, and an O-ring I is installed in the ring groove to ensure the seal with the control cabinet through the O-ring I.

[0013] A through hole is opened on the outer wall of the rod part of the new connecting bolt, and this through hole is communicated with the second through hole.

[0014] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0015] (1) An on-line test device for a pilot-operated safety valve in a nuclear power plant provided by the present invention can replace the original connecting bolt as the connecting device between the RRA pilot-operated safety valve control cabinet and the impulse pipeline, and can ensure the seal and normal operation function of the safety valve pilot control cabinet;

[0016] (2) An on-line test device for a pilot-operated safety valve in a nuclear power plant provided by the present invention can isolate the control cabinet of the pilot-operated safety valve under the condition of full water in the system by introducing a needle valve.

[0017] (3) An on-line test device for a pilot-operated safety valve in a nuclear power plant provided by the present invention is provided with quick connectors, which can facilitate the connection of the test bench, is beneficial to the implementation of the entire pressure setting process, and avoids the damage of connection bolts and equipment caused by the disassembly and assembly problems of pulse pipelines in the original design.

[0018] (4) An on-line test device for a pilot-operated safety valve in a nuclear power plant provided by the present invention is provided with quick connectors, which is convenient for the implementation of the water filling and air exhausting work of the control cabinet to the valve control pipeline and the drainage pipeline after the pressure setting work is completed.

[0019] (5) An on-line test device for a pilot-operated safety valve in a nuclear power plant provided by the present invention is provided with three sealing rings and locking nuts, which can ensure the correct state of the control cabinet in the operation mode or the pressure setting mode.

[0020] (6) An on-line test device for a pilot-operated safety valve in a nuclear power plant provided by the present invention can optimize the pressure setting work of the pilot-operated safety valve in the RRA system, is used to isolate the control cabinet from the RRA system and connect the test bench at the same time, makes the connection and disassembly of the test bench more convenient, makes the pressure setting work more rapid and efficient, effectively protects the equipment at the same time, and shortens the pressure setting construction period.

[0021] 1. The device has two modes: operation mode and on-line setting mode. The state of the operation mode is as Figure 2 shown. The original aperture design makes the device have good medium flow performance; the state of the on-line calibration mode is as Figure 1 shown. By changing the position of the O-ring of the flow hole, the mode switching of the device is realized; the design of the needle valve provides the possibility for the introduction of the test bench pressure; the design of the upper and lower three-stage O-rings ensures that the device has good sealing performance in any mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 It is a schematic structural diagram of an on-line test device for a pilot-operated safety valve in a nuclear power plant provided by the present invention in the on-line setting mode;

[0024] Figure 2It is a schematic structural diagram of an on-line test device for a pilot-operated safety valve in a nuclear power plant under an operating mode provided by the present invention;

[0025] In the figure: 1 - new connecting bolt, 2 - locking nut, 3 - O-ring seal Ι, 4 - needle valve, 5 - quick connector, 6 - O-ring seal ΙΙ. Specific embodiments

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention 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 cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0029] In the prior art, the control cabinet and the banjo joint are connected by connecting bolts. An on-line test device for a pilot-operated safety valve in a nuclear power plant provided by the present invention is installed at the connection between the control cabinet and the banjo joint as an alternative to the connecting bolts.

[0030] Such as Figure 1 And Figure 2As shown in the figure, an on-line test device for a pilot-operated safety valve in a nuclear power plant provided by the present invention includes: a new connecting bolt 1, a locking nut 2, an O-ring seal Ι 3, a needle valve 4, a quick connector 5, and an O-ring seal Ⅱ 6. A three-stage through hole with different diameters is opened from the head of the new connecting bolt 1. The first-stage through hole is located at the head of the new connecting bolt 1, with a length less than the height of the head, and internal threads are provided on the inner wall of the first-stage through hole. The second-stage through hole is connected to the first-stage through hole, with a diameter smaller than that of the first-stage through hole. The second-stage through hole penetrates into the rod part of the new connecting bolt 1, and its height is located at the middle position of the rod part. The third-stage through hole is connected to the second-stage through hole, with a diameter smaller than that of the second-stage through hole.

[0031] The needle valve 4 is a stepped shaft. The diameter of the first-stage shaft is the same as the diameter of the second-stage through hole of the new connecting bolt 1, and the length is less than the height of the second-stage through hole. An external thread is provided outside the second-stage diameter shaft, which is matched with the internal thread of the first-stage through hole of the new connecting bolt 1, and the length is greater than the height of the first-stage through hole. The diameter of the third-stage shaft is greater than the diameter of the first-stage through hole of the new connecting bolt 1. The fourth-stage shaft is a conical structure, and an external thread is provided on its outer wall. A through hole is opened at the central position of the needle valve 4.

[0032] The quick connector 5 is a two-stage shaft structure. A groove is opened inside the lower-stage shaft, and internal threads are provided on the inner wall of the groove, which are connected with the external thread of the fourth-stage shaft of the needle valve 4 in a matching manner.

[0033] The needle valve 4 is inserted from the head of the new connecting bolt 1. A locking nut 2 is provided on the upper end surface of the new connecting bolt 1, and the insertion depth of the needle valve 4 is adjusted through the locking nut 2.

[0034] A ring groove is opened on the outer wall of the first-stage shaft, and the O-ring seal Ⅱ 6 is installed in the ring groove. The seal between the first-stage shaft and the second-stage through hole is ensured through the O-ring seal Ⅱ 6.

[0035] A ring groove is opened on the outer wall of the rod part of the new connecting bolt 1, and the O-ring seal Ι 3 is installed in the ring groove. The seal with the control cabinet is ensured through the O-ring seal Ι 3.

[0036] A through hole is opened on the outer wall of the rod part of the new connecting bolt 1, and this through hole is communicated with the second-stage through hole.

[0037] The working principle of the present invention is as follows:

[0038] This device has two operating modes: the operating mode and the on-line calibration mode.

[0039] 1. During the normal operation of the control cabinet, the device is in the operating mode. For example, Figure 2As shown, the system medium enters the control cabinet through the side opening of the device and the middle through-hole of the new connecting bolt 1, ensuring the smooth entry of the RRA system medium into the control cabinet and the realization of the normal function of the valve. Secondly, through the cooperation with the sealing gasket, the on-line calibration device can ensure that there is no leakage in the connection between the control cabinet and the banjo joint. The end of the needle valve 4 needs to be adjusted to exceed the side opening of the device, and the expected position of the needle valve 4 can be determined by checking the height of the threaded part of the needle valve 4 leaking out. The position of the needle valve 4 is locked by the lock nut 2 to ensure the normal state of the control cabinet and maintain the Figure 2 state during operation. The flow channel of the needle valve 4 in the on-line device is filled with the medium from the RRA system. The quick connector 5 serves as the sealing boundary, which can withstand the highest pressure during the normal operation of the RRA system and has good sealing performance to ensure the normal operation function of the RRA pilot-operated safety valve. When the quick connector 5 leaks, it can be visually inspected and blocked online, that is, blocked with the closed female head of the quick connector to ensure the sealing of the control cabinet.

[0040] 2. During pressure calibration, the device is in the on-line calibration mode. The bottom surface of the O-ring Ι3 blocks the lower hole of the banjo joint, providing a prerequisite for on-line calibration. Secondly, loosen the lock nut 2 to close the needle valve 4 downward until the side opening of the device reaches the middle of the two O-rings Ⅱ6. The expected position of the needle valve 4 can be determined by checking the height of the threaded part of the needle valve 4 leaking out. The two O-rings Ⅱ6 on the needle valve reliably isolate the system medium, and the position of the needle valve 4 is locked by the lock nut 2, such as Figure 1 ; The test bench is connected to the on-line calibration device through a high-pressure hose with a quick connector. After the bench is connected to the control cabinet through the on-line device, the medium in the bench enters the control cabinet through the middle flow channel of the needle valve 4 and the middle opening of the new connecting bolt 1. At this time, the pressure calibration of the control cabinet can be realized by adjusting the pressure of the bench. After the test is completed and the test bench is depressurized, remove the high-pressure hose with the quick connector. At this time, the position of the needle valve 4 on the on-line device remains unchanged, and it will return to the position in the operation mode after the water filling and air exhausting work is completed. The quick connector between the device and the high-pressure hose is a plug-and-play connection with self-locking, which is convenient and fast to connect, saving the time of the entire pressure calibration work. At the same time, good sealing ensures the smooth implementation of the entire pressure calibration work.

[0041] 3. When filling with water and exhausting air, use a metal hose with a quick connector to connect the on-line device to the water injection filter. After completing the air exhausting work, carry out the water filling and air exhausting work for the control pipeline and the drainage pipeline between the control cabinet and the main valve. After the water filling and air exhausting work is completed, restore the needle valve 4 of the on-line test device to the operation mode. The expected position of the needle valve can be determined by checking the height of the threaded part leaking out of the needle valve 4. Finally, lock the position of the needle valve 4 with the lock nut 2. The introduction of this device facilitates the water filling and air exhausting work after the pressure setting of the control cabinet. Compared with the previous method of disassembling the drainage pipeline, it has the following advantages:

[0042] ① No air is introduced;

[0043] ② It is easy to operate and saves the time for equipment connection;

[0044] ③ It reduces the irradiation time of personnel.

[0045] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

[0046] In addition, it should be understood that although this specification is described according to the embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An on-line test device for a pilot-operated safety valve of a nuclear power plant, characterized in that: It includes a new connecting bolt (1), a lock nut (2), a needle valve (4), and a quick connector (5); a through hole is opened from the head at the center of the new connecting bolt (1), the needle valve (4) is inserted from the head of the new connecting bolt (1), a lock nut (2) is provided on the upper end surface of the new connecting bolt (1), and the insertion depth of the needle valve (4) is adjusted by the lock nut (2); the quick connector (5) is connected to the top of the needle valve (4). Three through holes with different diameters are opened from the head at the center of the new connecting bolt (1). The first through hole is located at the head of the new connecting bolt (1), and its length is less than the height of the head. Internal threads are provided on the inner wall of the first through hole; the second through hole is connected to the first through hole, and its diameter is smaller than that of the first through hole. The second through hole penetrates into the rod part of the new connecting bolt (1), and its height is at the middle position of the rod part; the third through hole is connected to the second through hole, and its diameter is smaller than that of the second through hole. The needle valve (4) is a stepped shaft. The diameter of the first shaft is the same as the diameter of the second through hole of the new connecting bolt (1), and its length is less than the height of the second through hole; external threads are provided on the outer wall of the second diameter shaft, which are matched with the internal threads of the first through hole of the new connecting bolt (1), and its length is greater than the height of the first through hole; the diameter of the third shaft is greater than the diameter of the first through hole of the new connecting bolt (1); the fourth shaft is a conical structure, and external threads are provided on its outer wall. A ring groove is opened on the outer wall of the rod part of the new connecting bolt (1), and an O-ring seal Ι (3) is installed in the ring groove. The seal with the control cabinet is ensured by the O-ring seal Ι (3).

2. An on-line test device for a pilot-operated safety valve of a nuclear power plant according to claim 1, characterized in that: The quick connector (5) is a two-shaft structure. A groove is opened inside the lower shaft, and internal threads are provided on the inner wall of the groove, which are connected in a threaded manner with the external threads of the fourth shaft of the needle valve (4).

3. The on-line test device for the pilot-operated safety valve of a nuclear power plant according to claim 1, characterized in that: A through hole is opened at the center position of the needle valve (4).

4. The on-line test device for a pilot-operated safety valve of a nuclear power plant according to claim 2, characterized in that: A ring groove is opened on the outer wall of the first shaft, and an O-ring seal Ⅱ (6) is installed in the ring groove. The seal between the first shaft and the second through hole is ensured by the O-ring seal Ⅱ (6).

5. An on-line test device for a pilot-operated safety valve of a nuclear power plant according to claim 1, characterized in that: A through hole is opened on the outer wall of the rod part of the new connecting bolt (1), and this through hole is communicated with the second through hole.

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