A device for video inspection of a guide vane of a main pump of a nuclear power unit and an inspection method thereof

Abstract

A kind of nuclear power unit main pump guide vane video inspection device, including: guide pipe, rotating hand wheel, limiting washer, guide pipe support, video lens, video cable, video output device and support ring base;Using the positioning of the inspection device of the application is more reliable, the stability is good in the process of inspection, can resist the interference caused by fluid movement when underwater inspection, so as to ensure the image quality of video inspection inspection method is a safe, reliable, efficient unit main pump guide vane weld, the inspection method of the application, can effectively solve the problem that nuclear power unit main pump guide vane weld and other main pump guide vanes with similar structure are difficult to be comprehensively and effectively inspected guide vane weld.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of in-service inspection of nuclear power plants, and particularly relates to a device for video inspection of guide vanes of a main pump of a nuclear power unit and a method for inspecting the same. BACKGROUND

[0002] The main coolant pump of a nuclear power unit is one of the important main devices of a nuclear reactor, and its main function is to maintain the circulation of the coolant of the primary loop of the reactor. The impeller of the main pump of a certain nuclear power unit is of a centrifugal type. In order to stabilize the flow at the outlet of the impeller and improve the comprehensive performance of the pump, such as the lift and efficiency, guide vanes are arranged in the pump shell to stabilize the flow at the outlet of the impeller. The guide vanes are 13 pieces arranged in a circumferential direction and are welded with the upper and lower guide trays. The upper guide tray is welded to the flange section of the pump body. During the refueling overhaul, a video inspection device is used to implement periodic in-service inspection of the fillet weld between the guide vanes and the upper and lower guide trays of the pump body.

[0003] During the inspection of the fillet weld between the guide vanes and the upper and lower guide trays, the water level in the pump body is basically level with the top end of the flange section, the guide vanes and the guide trays are located at a depth of 720mm to 1400mm under water, the primary loop coolant is in a flowing state, the flow field in the pump body is relatively complex, the inlet direction of the flow passage of the guide vanes is non-centripetal and the inlet is relatively narrow, the shape of the flow passage is twisted and the depth is relatively deep, and in addition, the rigidity of the video cable is insufficient and it is difficult to control the trajectory of the camera. Therefore, the inspection personnel can only insert the video camera into the water to inspect the fillet weld at the inlet of the guide vanes and the nearby area, and the fillet weld in the deep part of the flow passage cannot be effectively inspected due to the inability of the camera to be inserted deep.

[0004] Therefore, in order to solve the problem that the fillet weld between the guide vanes and the upper and lower guide trays of the main pump of the unit cannot be comprehensively and effectively inspected by using a video inspection device, improve the inspection efficiency of the weld, shorten the inspection period, reduce the collective dose of the radiation received by the operation team, reduce the safety risk of personnel and equipment during the inspection, improve the overhaul performance index of the nuclear power plant, and design a device for video inspection of guide vanes of a main pump of a nuclear power unit and a method for inspecting the same. SUMMARY

[0005] The present application provides a device for video inspection of guide vanes of a main pump of a nuclear power unit and a method for inspecting the same, which are used to solve the technical problem that the fillet weld between the guide vanes and the upper and lower guide trays of the main pump of the unit cannot be comprehensively and effectively inspected by using a video inspection device.

[0006] The technical scheme of the present application is as follows:

[0007] A device for video inspection of guide vanes of a main pump of a nuclear power unit, comprising: a guide pipe, a rotating hand wheel, a limiting gasket, a guide pipe support, a video lens,

[0008] a video cable, a video output device and a support ring base;

[0009] The guide tube is a hollow structure, the top end of the guide tube is matched with a guide tube support through a gap, the top end of the guide tube is screwed with a rotating hand wheel, and a limiting gasket is arranged between the guide tube and the rotating hand wheel; the bottom end of the guide tube is screwed with a video lens; one end of the video cable is inserted into the inside of the guide tube from the top end of the guide tube, and the other end of the video cable is connected with the video lens after being taken out from the bottom end of the guide tube; the other end of the video cable is provided with a video output device; and the bottom of the guide tube support is mounted on the support ring base.

[0010] The guide tube is an integrated hollow tubular structure, the top end to the bottom end of the guide tube is sequentially divided into a guide tube vertical rotation section, a guide tube intermediate transition section and a guide tube circular arc extension section; one end of the guide tube vertical rotation section is connected with one end of the guide tube intermediate transition section in a circular arc shape, and the other end of the guide tube intermediate transition section is connected with the guide tube circular arc extension section in a circular arc shape;

[0011] An outer thread and a guide tube limiting groove are arranged on the outer surface of the other end of the guide tube vertical rotation section; the other end of the guide tube vertical rotation section is threadedly connected with the rotating hand wheel;

[0012] The length of the guide tube intermediate transition section is consistent with the arc radius length formed by fitting the center flow line of the main pump inner vane flow passage;

[0013] The circular arc bending angle between the guide tube intermediate transition section and the guide tube circular arc extension section makes the guide tube circular arc extension section always coincide with the center flow line of the vane flow passage.

[0014] The inner wall of the rotating hand wheel threadedly connected with the outer wall of the top end of the guide tube is provided with a hand wheel limiting groove, and the width of the hand wheel limiting groove is the same as that of the guide tube limiting groove.

[0015] The limiting gasket is provided with a limiting key.

[0016] The guide tube support includes a support column, a connecting piece, a guide tube support part, a positioning key A, a positioning key B and a positioning key C; the positioning key A, the positioning key B and the positioning key C are uniformly arranged in the circumferential direction of the bottom of the support column, and the side of the top of the support column is welded with the guide tube support part through the connecting piece;

[0017] The width of the positioning key B and the positioning key C is the same, and the width of the positioning key A is greater than that of the positioning key B and the positioning key C;

[0018] The bottom of the support column is fixedly mounted on the support ring base through the positioning key A, the positioning key B and the positioning key C, the guide tube support part is a hollow cylindrical structure, and the guide tube is inserted into the inside of the guide tube support part.

[0019] The support ring base is a whole circular ring structure, and two guide columns are symmetrically arranged on the lower surface of the support ring base; 13 support mounting seats are uniformly arranged on the upper surface of the support ring base in the circumferential direction, and the 13 support mounting seats correspond to the positions of the 13 guide vane flow passages in the main pump body respectively; three positioning grooves are arranged on each support mounting seat, and are used for cooperating with the positioning keys A, B and C at the bottom of the guide pipe support.

[0020] A position indicating arrow is further arranged on the upper surface of the support ring base, and when the support ring base is installed on the flange surface of the main pump body, the position indicating arrow points to the center line of the main pump outlet connector.

[0021] A check method of the video inspection device for the main pump guide vane of the nuclear power unit as described above comprises the following steps:

[0022] Step one, after the assembly and installation of the inspection device are completed, the rotating hand wheel is shaken, the guide pipe circular arc extension section is slowly shaken into the first guide vane flow passage, and the shaking-in process is observed, and the shaking-in action is stopped after the video lens moves to the farthest end position of the angle weld that can be observed;

[0023] Step two, after confirming that the real-time display and video recording functions of the video output device are both set, the rotating hand wheel is shaken, the guide pipe and the video lens are slowly shaken out, the shaking-out process lasts for more than or equal to 6 seconds to ensure that the movement rate of the video lens is less than 100 mm / s, and in the shaking-out process, the inspector should synchronously observe the surface state of the weld, and if there is any abnormality, the movement should be stopped in time, the picture is enlarged for observation, and the image recording at multiple angles is supplemented;

[0024] Step three, after the guide vane weld inspection work in one guide vane flow passage is completed, it is confirmed that the video image is saved correctly, then the guide pipe support is sequentially inserted into the remaining 12 support mounting seats 13 in clockwise order, so that the guide vane weld inspection work in the remaining 12 guide vane flow passages is completed one by one, and all video recordings are saved.

[0025] The beneficial effects of the present application are as follows:

[0026] 1) The inspection device designed in the present application is light and simple in material structure, is assembled through key grooves and threads, can be manually installed and disassembled without special tools, will not cause damage to the inspected equipment during use, and has fewer component parts;

[0027] 2) Each component of the inspection device has a positioning or limiting structure, the inspector can quickly install and accurately complete the inspection, the operation is convenient, which is beneficial to shorten the inspection period and greatly reduce the risk of human error;

[0028] 3) The inspection device of the present application can complete the installation and assembly of the device in advance, and only two workers are needed to complete the inspection task during the implementation process, which can save labor cost and reduce collective radiation dose, and realize radiation protection optimization;

[0029] 4) Compared with the inspection method of the conventional handheld long rod camera or handheld guide tube, the device positioning is more reliable, the stability during the inspection process is good, and the interference caused by fluid movement during underwater inspection can be resisted, so that the image quality of video inspection is ensured;

[0030] 5) The inspection device of the present application can accurately position the center of each flow channel center line, and rely on the positioning of the guide tube support and the adjustment of the rotating hand wheel to ensure that the video lens is located on the center line of the flow channel during movement, so that the inspection of four welds is effectively completed in one stroke, which is not only high in inspection efficiency, but also good in movement track repeatability, and is beneficial to the comparison and analysis of video images during inspection, and provides help for the judgment of abnormal display by the inspector;

[0031] 6) The inspection method using the inspection device of the present application is a safe, reliable and efficient inspection method for the guide vane weld of the nuclear power unit main pump, which can effectively solve the problem that the guide vane weld of the nuclear power unit main pump and other guide vane welds with similar structures are difficult to be inspected comprehensively and effectively. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The nuclear power unit main pump guide vane video inspection device designed by the present application;

[0033] Figure 2 The guide tube structure diagram described in the present application

[0034] Figure 3 The guide tube limiting groove structure diagram described in the present application;

[0035] Figure 4 The rotating hand wheel structure diagram described in the present application

[0036] Figure 5 The limiting gasket structure diagram described in the present application

[0037] Figure 6 The guide tube support structure diagram described in the present application

[0038] Figure 7 The support ring base structure diagram described in the present application

[0039] Figure 8 The video lens in the video inspection device designed by the present application shakes into the main pump inner guide vane in the inspection starting stage

[0040] Figure 9 The video camera in the video inspection device designed for the present invention swings into the top view of the guide vanes inside the main pump at the beginning of the inspection

[0041] Figure 10 A top view of the farthest position of the guide vanes in the main pump during inspection by the video camera in the video inspection device designed for the present invention;

[0042] Figure 11 This is a schematic diagram of the arc fitted by the central streamline of the guide vane flow channel and the central streamline structure of the guide vane flow channel described in the present invention.

[0043] Among them: 1-guide tube; 2-rotating hand wheel; 3-limiting gasket; 4-guide tube bracket; 5-video lens;

[0044] 6-Video cable; 7-Video output device; 8-Support ring base; 9-Guide tube limit groove; 10-Handwheel limit groove; 11-Limit key; 12-Guide column; 13-Bracket mounting support; 14-Position indicator arrow; 15-Main pump flange surface; 16-Guide vane; 17-Guide vane flow channel; 18-Main pump body; 19-Guide tube vertical rotation section; 20-Guide tube middle transition section; 21-Guide tube arc extension section; 22-Bracket support column; 23-Guide tube support part; 24-Location key A; 25-Location key B; 26-Location key C; 27-Connecting piece; 28-Arc fitted by the center line of the guide vane flow channel; 29-Center of the arc fitted by the center line of the guide vane flow channel; 30-Center of the guide vane tray, 31-Center streamline of the guide vane flow channel; 32-Main pump outlet pipe. DETAILED DESCRIPTION

[0045] The following describes in detail a video inspection device and method for inspecting guide vanes of a main pump of a nuclear power plant according to the present invention in conjunction with the accompanying drawings and embodiments.

[0046] A video inspection device for the guide vanes of a main pump of a nuclear power unit, comprising: a guide tube 1, a rotating hand wheel 2, a limit washer 3, a guide tube bracket 4, a video lens 5, a video cable 6, a video output device 7, and a support ring base 8;

[0047] The guide tube 1 is a hollow structure, and a guide tube bracket 4 is fitted in the gap of the outer wall at the top of the guide tube 1. The top of the guide tube 1 is screwed to a rotating handwheel 2, and a limiting gasket 3 is also provided between the guide tube 1 and the rotating handwheel 2; the bottom end of the guide tube 1 is screwed to a video lens 5; one end of the video cable 6 passes through the interior of the guide tube 1 from the top end, and comes out from the bottom end of the guide tube 1 and is connected to the video lens 5; the other end of the video cable 6 is provided with a video output device 7; the bottom of the guide tube bracket 4 is installed on a support ring base 8.

[0048] In order to ensure sufficient structural strength, reduce the weight of the device, and avoid damaging the inside of the pump body by the inspection device, all components in the inspection device are made of polyethylene material and are formed by one-time processing.

[0049] The guide pipe 1 is an integrated hollow tubular structure, and the top end to the bottom end of the guide pipe 1 is sequentially divided into a guide pipe vertical rotation section 19, a guide pipe intermediate transition section 20, and a guide pipe circular arc extension section 21; one end of the guide pipe vertical rotation section 19 is circularly arc-bent connected with one end of the guide pipe intermediate transition section 20, and the other end of the guide pipe intermediate transition section 20 is circularly arc-bent connected with the guide pipe circular arc extension section 21;

[0050] A plurality of fitting points are selected on the center streamline of the guide vane flow channel in the main pump, and the plurality of fitting points are connected to form a guide vane flow channel center streamline circular arc;

[0051] An outer thread and a guide pipe limiting groove 9 are arranged on the outer surface of the other end of the guide pipe vertical rotation section 19; the other end of the guide pipe vertical rotation section 19 is threadedly connected with the rotating hand wheel 2; and the guide pipe vertical rotation section 19 functions as fixing the guide pipe and transmitting the rotating torque.

[0052] The length of the guide pipe intermediate transition section 20 is consistent with the radius length of the circular arc formed by fitting the center streamline of the guide vane flow channel in the main pump; and the guide pipe intermediate transition section 20 can ensure that the guide pipe circular arc extension section 21 is sent into the guide vane flow channel during the rotation of the guide pipe 1;

[0053] The circular arc bending angle between the guide pipe intermediate transition section 20 and the guide pipe circular arc extension section 21 makes the guide pipe circular arc extension section 21 always coincide with the center streamline of the guide vane flow channel;

[0054] The guide pipe 1 is always not in contact with the inner wall of the guide vane and the guide vane flow channel in the main pump, and the guide pipe circular arc extension section 21 always coincides with the center streamline of the guide vane flow channel during the extension into the guide vane flow channel.

[0055] The bending line type of the circular arc bending between the other end of the guide pipe intermediate transition section 20 and the guide pipe circular arc extension section 21 is formed according to the fitting of the guide vane flow channel center streamline 31; the center of the fitting circular arc of the guide vane flow channel center streamline coincides with the axis of the guide pipe vertical rotation section 19, and the schematic diagram is shown in Figure 11 During the rotation of the guide pipe, the guide pipe circular arc extension section 21 can overlap with the guide vane flow channel center streamline 31 when extending into the guide vane flow channel 17, so as to ensure that the guide pipe 1 and the video lens 5 do not collide with the inside of the main pump during the inspection process, and to ensure that the video lens 5 can completely cover the guide vanes and the upper and lower guide tray welds at each position of the flow channel.

[0056] The inner wall of the rotating hand wheel 2 connected with the outer wall of the top end of the guide pipe 1 is provided with a hand wheel limiting groove 10, and the width of the hand wheel limiting groove 10 is the same as that of the guide pipe limiting groove 9.

[0057] The limiting key 11 is arranged on the limiting gasket 3.

[0058] The rotating hand wheel 2 is a handheld part of the operator during the inspection process, and the operator drives the guide pipe 1 to move by rotating the hand wheel clockwise or counterclockwise, so as to send the video lens 5 to the vicinity of the inspection site and withdraw it after the video inspection is completed. The rotating hand wheel 2 is connected with the vertical rotating section 19 of the guide pipe through threads, and the depth of the guide pipe 1 extending into the main pump body can be accurately adjusted through the thread stroke, and the corresponding guide vane flow passage inlet is aligned. The limiting groove 10 in the inner wall of the rotating hand wheel 2 and the threaded portion limiting groove 9 of the guide pipe 1 are of the same width, and after the threaded stroke adjustment of the guide pipe 1 is completed, the limiting gasket 3 with a limiting key 11 is inserted to lock the threads, so as to prevent the relative rotation between the rotating hand wheel 2 and the guide pipe 1.

[0059] The video lens 5 is an industrial video inspection camera, which has a focal length adjustment and a 360-degree rotation function, and can fully observe each part of the fillet weld in the flow passage.

[0060] The guide pipe support 4 comprises a support support column 22, a connecting piece 27, a guide pipe support part 23, a positioning key A 24, a positioning key B 25 and a positioning key C 26, the positioning key A 24, the positioning key B 25 and the positioning key C 26 are uniformly arranged in the circumferential direction of the bottom of the support support column 22, and the guide pipe support part 23 is welded on one side of the top of the support support column 22 through the connecting piece 27.

[0061] The widths of the positioning key B 25 and the positioning key C 26 are the same, and the width of the positioning key A 24 is greater than the widths of the positioning key B 25 and the positioning key C 26.

[0062] The bottom of the support support column 22 is fixedly installed on the support ring base 8 through the positioning key A 24, the positioning key B 25 and the positioning key C 26, the guide pipe support part 23 is a hollow cylindrical structure, and the guide pipe 1 penetrates from the inside of the guide pipe support part 23.

[0063] The support ring base 8 is a whole circular ring structure, and the lower surface of the support ring base 8 is symmetrically provided with two guide columns 12.

[0064] The two guide columns 12 are symmetrically distributed on the lower surface of the support ring base 8, and the upper surface of the support ring base 8 is uniformly provided with 13 support mounting seats 13 in the circumferential direction, which correspond to the positions of the 13 guide vane flow passages in the main pump body respectively; each support mounting seat 13 is provided with three positioning grooves for cooperating with the positioning keys A24, B25 and C26 at the bottom of the guide pipe support 4.

[0065] The guide pipe support 4 is connected and fixed with the positioning grooves on the support ring base 8; the upper end of the guide pipe support 4 cooperates with the connected rotary hand wheel 2 and the guide pipe 1, thereby providing a fixed point of the guide pipe 1 during the inspection process, and the center of the rotary hand wheel 2 rotation, which coincides with the center of the arc fitting the center streamline of the flow passage to be inspected.

[0066] The upper surface of the support ring base 8 is further provided with a position indicating arrow 14, which points to the center line of the main pump outlet connector 32 when the support ring base 8 is installed on the flange surface of the main pump body.

[0067] In the embodiment, the assembly method of the video inspection device for the guide vane of the main pump of the nuclear power unit is as follows:

[0068] Firstly, the guide pipe 1 is inserted through the guide pipe support 4, the rotary hand wheel 2 is threadedly connected with the guide pipe 1, the depth of the guide pipe 1 inserted into the pump body is adjusted by adjusting the threaded stroke, the limiting grooves 9 and 10 on the inner wall of the rotary hand wheel 2 and the guide pipe 1 are aligned after the threaded stroke adjustment is completed, and the limiting gasket 3 is inserted to lock the rotary hand wheel 2 and the guide pipe 1. The video cable 6 is inserted from the vertical rotation segment 19 of the guide pipe and connected with the video lens 5 after being taken out from the arc extension segment 21 of the guide pipe.

[0069] Then, the support ring base 8 is installed on the flange surface 15 of the pump body by using the double guide columns 12, and the position indicating arrow 14 is ensured to point to the center line of the pump outlet connector. The first support mounting seat 13 downstream of the position indicating arrow 14 on the support ring base 8 is selected in a clockwise direction, the guide pipe support 4 is inserted, the guide pipe 1 is assembled and fixed by using the positioning keys A24, B25 and C26, and the video cable 6 at the top end of the guide pipe 1 is connected with the video output device 7, so as to complete the assembly of the entire inspection device.

[0070] A kind of inspection method for the video inspection device for the guide vane of the main pump of the nuclear power unit as described above, comprising the following steps:

[0071] Step one, after completing the assembly and installation of the inspection device, the rotary hand wheel 2 is shaken, the guide pipe arc extension segment 21 is slowly shaken into the first guide vane flow passage, and the video image is observed during the shaking process, and the shaking action is stopped after the video lens 5 moves to the farthest end position of the observable fillet weld.

[0072] Step two, confirm that the video output device 7 real-time display and video recording function has been set, shake the rotating hand wheel 2, slowly shake out the guide tube 1 and video lens 5, shake out the process duration ≥ 6 seconds, to ensure that the video lens movement rate is less than 100 mm / s, in the process of shaking out, the inspector should be observed simultaneously weld surface state, if there is an exception should be stopped in time, the movement of the enlarged view and supplementary multi-angle image recording;

[0073] Step three, after completing a guide vane flow passage of guide vane weld inspection work, should confirm the video image save no error, then according to clockwise order in turn into the guide tube bracket 4 installed in the remaining 12 support seat 13, thus completing the remaining 12 guide vane flow passage in guide vane weld inspection work, and save all video recording.

[0074] The disassembly method of the video inspection device for the guide vane of the nuclear power unit main pump is as follows:

[0075] First, disconnect the video cable 6 and the video output device 7. Second, disconnect the guide tube bracket 4 and the bracket mounting seat 13, disconnect the guide tube 1, rotating hand wheel 2 and limit washer 3. Take out the guide tube 1 from the guide tube bracket 4, and disassemble the video lens 5, pull out the video cable 6. From the main pump flange 15 on the disassembly of the inspection device support ring base 8;

[0076] Finally, when all the components are disassembled, decontaminate.

[0077] The above has made detailed description to the embodiment of the present application, the present application is not limited to the above examples, within the knowledge of those skilled in the art, still can make various changes without departing from the purpose of the present application.

Claims

1. A video inspection device for the guide vanes of the main pump of a nuclear power unit, characterized in that: include: Guide tube (1), rotating hand wheel (2), limit washer (3), guide tube bracket (4), video lens (5), A video cable (6), a video output device (7) and a support ring base (8); the guide tube (1) is a hollow structure, the outer wall of the top end of the guide tube (1) is gap-fitted with a guide tube bracket (4), the top end of the guide tube (1) is screwed to a rotating hand wheel (2), and a limiting gasket (3) is provided between the guide tube (1) and the rotating hand wheel (2); the bottom end of the guide tube (1) is screwed to a video lens (5); one end of the video cable (6) passes through the inside of the guide tube (1) from the top end of the guide tube (1), and passes out from the bottom end of the guide tube (1) and is connected to the video lens (5); the other end of the video cable (6) is provided with a video output device (7); the bottom of the guide tube bracket (4) is installed on the support ring base (8); The guide tube (1) is an integrated hollow tubular structure. The guide tube (1) is divided into a guide tube vertical rotation section (19), a guide tube intermediate transition section (20), and a guide tube circular arc insertion section (21) from the top to the bottom. One end of the guide tube vertical rotation section (19) is connected to one end of the guide tube intermediate transition section (20) in a circular arc shape, and the other end of the guide tube intermediate transition section (20) is connected to the guide tube circular arc insertion section (21) in a circular arc shape. The outer surface of the other end of the vertical rotating section (19) of the guide tube is provided with an external thread and a guide tube limiting groove (9); the other end of the vertical rotating section (19) of the guide tube is threadedly connected to the rotating hand wheel (2); the length of the intermediate transition section (20) of the guide tube is consistent with the length of the arc radius formed by fitting the central streamline of the guide vane flow channel in the main pump; The arc bending angle between the guide tube intermediate transition section (20) and the guide tube arc extension section (21) ensures that the guide tube arc extension section (21) always coincides with the central streamline of the guide vane flow channel; The inner wall of the rotating hand wheel (2) threadedly connected to the outer wall of the top end of the guide tube (1) is provided with a hand wheel limiting groove (10), and the width of the hand wheel limiting groove (10) is the same as that of the guide tube limiting groove (9); A limit key (11) is provided on the limit gasket (3).

2. The video inspection device for guide vanes of a nuclear power plant main pump according to claim 1, characterized in that: The guide tube bracket (4) comprises: a bracket support column (22), a connecting piece (27), a guide tube support portion (23); a positioning key A (24), a positioning key B (25), and a positioning key C (26); the positioning keys A (24), the positioning keys B (25), and the positioning keys C (26) are evenly arranged in the circumferential direction of the bottom of the bracket support column (22); and the guide tube support portion (23) is welded to one side of the top of the bracket support column (22) via the connecting piece (27); The widths of the positioning key B (25) and the positioning key C (26) are the same, and the width of the positioning key A (24) is greater than the widths of the positioning key B (25) and the positioning key C (26); The bottom of the bracket support column (22) is fixedly mounted on the support ring base (8) via a positioning key A (24), a positioning key B (25) and a positioning key C (26). The guide tube support portion (23) is a hollow cylindrical structure, and the guide tube (1) is inserted into the guide tube support portion (23).

3. The video inspection device for the guide vanes of the main pump of a nuclear power unit according to claim 2, characterized in that: The support ring base (8) is an annular structure as a whole, and two guide columns (12) are symmetrically arranged on the lower surface of the support ring base (8); 13 bracket mounting supports (13) are evenly arranged in the circumferential direction of the upper surface of the support ring base (8), and the 13 bracket mounting supports (13) respectively correspond to the positions of 13 guide vane flow channels in the main pump body; each bracket mounting support (13) is provided with three positioning grooves for cooperating with the positioning key A (24), positioning key B (25) and positioning key C (26) at the bottom of the guide tube bracket (4).

4. The video inspection device for guide vanes of a nuclear power plant main pump according to claim 3 is characterized in that: A position indicating arrow (14) is also provided on the upper surface of the support ring base (8). When the support ring base (8) is mounted on the flange surface of the main pump body, the position indicating arrow (14) points to the center line of the main pump outlet pipe (32).

5. An inspection method for a video inspection device for a nuclear power plant main pump guide vane as claimed in claim 3, characterized in that The steps include: Step 1: After completing the assembly and installation of the inspection device, shake the rotating hand wheel (2) to slowly swing the arc extension section (21) of the guide tube into the first guide vane flow channel. Pay attention to the video image during the swing-in process. Stop the swing-in action after the video lens (5) moves to the farthest end position where the fillet weld can be observed; Step 2: Confirm that the real-time display and video recording functions of the video output device (7) have been set. Shake the rotary hand wheel (2) and slowly shake out the guide tube (1) and the video lens (5). The shaking-out process lasts for ≥ 6 seconds to ensure that the video lens movement rate is less than 100 mm / s. During the shaking-out process, the inspector should simultaneously observe the surface condition of the weld. If there is any abnormality, the movement should be stopped in time, and the picture should be zoomed in for observation and supplemented with multi-angle image recording; Step 3: After completing the inspection of the guide vane weld of one guide vane flow channel, confirm that the video image is saved correctly, then insert the guide tube bracket (4) into the remaining 12 bracket mounting brackets (13) in a clockwise order, thereby completing the inspection of the guide vane welds in the remaining 12 guide vane flow channels one by one, and save all the video recordings.

Images