Video inspection device for voltage stabilizer of nuclear power plant

Abstract

The invention discloses a nuclear power plant voltage stabilizer video inspection device. The nuclear power plant voltage stabilizer video inspection device comprises a supporting mechanism used for being positioned at a manhole of a voltage stabilizer, a winding mechanism used for winding and unwinding a flat cable, a support used for stretching into the voltage stabilizer, a camera unit used for inspection and the flat cable. The winding mechanism is arranged on the side, facing the outer side of the voltage stabilizer, of the supporting mechanism. The support is arranged on the side, facing the interior of the voltage stabilizer, of the supporting mechanism. The flat cable is wound on the winding mechanism and the tail end is connected with the camera unit; the camera shooting unit is suspended below the support so as to inspect the build-up welding layer on the inner surface of the voltage stabilizer. The whole video inspection device is installed and positioned at the manhole of the voltage stabilizer through the supporting mechanism, and the camera unit is hung in the voltage stabilizer through hanging connection of the cable so as to inspect a surfacing layer on the inner surface of the voltage stabilizer; most of the cable is stored through the winding mechanism arranged on the supporting mechanism, the problems that the cable is wound and knotted, and foreign matter falls off are solved, and the safety and reliability of video inspection are improved.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear power nondestructive testing, and in particular to a video inspection device for a voltage stabilizer in a nuclear power plant. Background Art

[0002] The pressurizer, also known as the volume compensator, is one of the important equipment in a pressurized water reactor nuclear power plant. The function of the pressurizer in the operation of a pressurized water reactor nuclear power plant is to compensate for the change in the volume of the primary water loop caused by the change in the temperature of the primary cooling water, adjust the working pressure of the primary coolant, and prevent the primary system equipment from being damaged due to excessive pressure or the volume boiling of the coolant in the reactor due to low pressure, causing the fuel rod overburning accident. The shell of the pressurizer is low-alloy steel, and the inner surface is welded with a 6mm to 8mm thick stainless steel weld layer to protect the shell metal from corrosion by boric acid solution. During operation, the weld layer on the inner surface of the pressurizer is subject to stress, corrosion, and high temperature, and is prone to defects such as fatigue cracks, which leads to the degradation of the quality of the pressurizer and affects nuclear safety. Therefore, according to regulatory requirements, the weld layer on the inner surface of the pressurizer must be inspected by video, and the inspection cycle is once every 3 years.

[0003] The pressurizer has a special structure, with a depth of 14 meters. There is only one manhole at the top, and the bottom is directly connected to the primary system pipeline. Once foreign matter is introduced, it is difficult to salvage, which poses a serious threat to the fuel assembly. In addition, after the pressurizer is opened, it is a radioactive contamination operation. The inspectors face the risk of external irradiation and body surface contamination. The operation process in the contaminated area is complicated and has high requirements for personnel and equipment.

[0004] The existing video inspection device for the voltage regulator of a nuclear power plant consists of seven parts: a winch, a support frame, a telescopic rod, a fall arrester, an inspection camera, a flat cable retractable disc, and a semi-flange fixing disc. It weighs 150 kg and has a complicated installation process. The operation time in the contaminated area is long and the exposure dose to personnel is high. In addition, the number of fasteners of the above-mentioned video inspection device reaches 514, and there is a high risk of foreign matter being introduced into the voltage regulator. In addition, there are four cables entering the manhole of the voltage regulator, including the main flat cable for control, the winch wire rope, and the fall arrest wire rope. During the installation and inspection of the video inspection device, they are prone to entanglement and knotting, resulting in equipment failure. There are major hidden dangers to the safety and reliability of the project. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an improved video inspection device for a voltage regulator of a nuclear power plant.

[0006] The technical solution adopted by the present invention to solve the technical problem is: to provide a video inspection device for a nuclear power plant stabilizer, comprising a support mechanism for positioning at a manhole of the stabilizer, a winding mechanism for retracting and releasing a flat cable, a bracket for extending into the stabilizer, a camera unit for inspection, and a flat cable;

[0007] The winding mechanism is arranged on a side of the supporting mechanism facing the outside of the voltage stabilizer, and the bracket is arranged on a side of the supporting mechanism facing the inside of the voltage stabilizer; the flat cable is wound on the winding mechanism and the end thereof is connected to the camera unit;

[0008] After being unwound from the winding mechanism, the flat cable is laid along the length direction of the bracket, so that the camera unit is suspended below the bracket to inspect the surfacing layer on the inner surface of the voltage stabilizer.

[0009] In some embodiments, one end of the bracket away from the supporting mechanism is located at the central axis of the stabilizer, so that the suspended camera unit is located at the central axis of the stabilizer and can move up and down along the central axis of the stabilizer.

[0010] In some embodiments, the flat cable is flat in shape, and a variety of signal lines are arranged in parallel inside the flat cable.

[0011] In some embodiments, the flat cable includes a high-definition video wire, a cable group, a flexible shaft, and a sheath, wherein the sheath is coated on the periphery of the high-definition video wire, the cable group, and the flexible shaft;

[0012] In the outer skin, the high-definition video cable is located in the middle position, a plurality of cables of the cable group are distributed on opposite sides of the high-definition video cable, and the flexible shaft is arranged at the outermost side of the cable group.

[0013] In some embodiments, the winding mechanism includes two oppositely disposed take-up plates, a take-up reel, a first anti-rotation gear, and an anti-falling assembly;

[0014] A winding space is defined between the two wire-taking plates, the wire-taking drum is arranged in the winding space and is rotatably connected to the wire-taking plates via a rotating shaft; the first anti-rotation gear is coaxially connected to the rotating shaft, and the anti-falling component is arranged on the wire-taking plate and meshes with the first anti-rotation gear.

[0015] In some embodiments, the anti-falling assembly includes a housing fixed on the take-up plate, a centrifugal ratchet shaft disposed in the housing and rotatable relative to the housing, a ratchet sleeved on the outer periphery of the centrifugal ratchet shaft and fixedly connected to the housing, a ratchet pawl eccentrically disposed on the centrifugal ratchet shaft, and a second anti-rotation gear coaxially disposed on the centrifugal ratchet shaft; the second anti-rotation gear meshes with the first anti-rotation gear;

[0016] The pawl rotates with the centrifugal ratchet shaft and is used to be inserted between the gear teeth of the ratchet to brake the rotation of the centrifugal ratchet shaft, and then brakes the first anti-rotation gear and the take-up disk linked thereto through the second anti-rotation gear.

[0017] In some embodiments, the ratchet is provided with two, which are arranged on the end surface of the centrifugal ratchet shaft away from the take-up plate and are centrally symmetrical about the center of the centrifugal ratchet shaft;

[0018] A limit pin is also provided on one side of each pawl facing the other pawl. The limit pin is protrudingly arranged on the end surface of the centrifugal ratchet shaft and is used to limit the swing amplitude of the pawl.

[0019] In some embodiments, the winding mechanism further includes a driving motor connected to and driving the rotating shaft to rotate, and an electromagnetic brake connected in series with the driving motor through the rotating shaft.

[0020] In some embodiments, the support mechanism includes a fixing seat for cooperating with the inner wall of the manhole of the voltage stabilizer and locking at the manhole, and a support frame connected to the fixing seat; the winding mechanism is fixedly connected to the support frame.

[0021] In some embodiments, the support includes at least one support rod, a first end of the support rod is fixed to the support mechanism, and an opposite second end extends toward the central axis of the stabilizer;

[0022] A reversing assembly for the flat cable to wrap around and pass through is disposed on the second end of the bracket; the reversing assembly comprises a wheel frame and a reversing roller rotatably disposed on the wheel frame.

[0023] The beneficial effects of the present invention are as follows: the entire video inspection device is installed and positioned at the manhole of the voltage stabilizer through the support mechanism, and the camera unit is suspended in the voltage stabilizer by hanging the flat cable to inspect the welding layer on the inner surface of the voltage stabilizer; most of the flat cable is received by the winding mechanism arranged on the support mechanism, so as to solve the problems of entanglement, knotting and foreign matter falling of the flat cable, and improve the safety and reliability of video inspection. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0025] Figure 1 It is a structural schematic diagram of a nuclear power plant pressurizer video inspection device and a manhole in cooperation with one embodiment of the present invention;

[0026] Figure 2 It is a structural schematic diagram of a winding mechanism in a video inspection device for a nuclear power plant pressurizer according to an embodiment of the present invention;

[0027] Figure 3 yes Figure 2 A longitudinal cross-sectional view of the winding mechanism shown;

[0028] Figure 4It is a structural schematic diagram of an anti-falling component in a winding mechanism of a video inspection device for a nuclear power plant pressurizer according to an embodiment of the present invention;

[0029] Figure 5 It is a schematic diagram of the matching structure of the bracket and the manhole in the video inspection device for a nuclear power plant pressurizer according to one embodiment of the present invention;

[0030] Figure 6 The diagram is a schematic diagram of the internal structure of a flat cable in a video inspection device for a nuclear power plant voltage regulator according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0032] like Figure 1 , Figure 2 As shown, a video inspection device for a nuclear power plant pressurizer according to an embodiment of the present invention may include a supporting mechanism 10, a winding mechanism 20 and a bracket 30 respectively arranged on opposite sides of the supporting mechanism 10, a camera unit 50, and a flat cable 40 connected to the camera unit 50.

[0033] The support mechanism 10 is used to be positioned at the manhole 100 of the voltage stabilizer as the support structure of the entire video inspection device. The entire video inspection device is installed and fixed at the manhole 100 to facilitate subsequent video inspection. The opposite sides of the support mechanism 10 are respectively facing the outside and the inside of the voltage stabilizer. The winding mechanism 20 is arranged on the side of the support mechanism 10 facing the outside of the voltage stabilizer, and is used to retract the flat cable 40. The bracket 30 is arranged on the side of the support mechanism 10 facing the inside of the voltage stabilizer, and is used to support and guide the flat cable 40. The flat cable 40 is stored by winding on the winding mechanism 20, and the end is released from the winding mechanism 20 and connected to the camera unit 50. After the flat cable 40 is released from the winding mechanism 20, it is laid along the length direction of the bracket 30, so that the camera unit 50 is suspended below the bracket 30 to inspect the surfacing layer on the inner surface of the voltage stabilizer.

[0034] The support mechanism 10 may include a fixing seat 11 for cooperating with the inner wall of the manhole 100 of the voltage stabilizer and being locked at the manhole 100 , and a support frame 12 connected to the fixing seat 11 ; the winding mechanism 20 is fixedly connected to the support frame 12 .

[0035] Specifically, the fixing seat 11 may further include an arc-shaped bottom plate that fits with the inner wall surface of the manhole 100, and a flange cover that matches the flange on the periphery of the manhole 100, and the arc-shaped bottom plate and the flange cover are integrally formed. The flange cover is provided with fixing holes, and the flange cover is fixedly connected to the flange on the periphery of the manhole 100 by bolts. One side of the support frame 12 fits with the flange cover of the fixing seat 11 through a connecting plate, and can be fixedly connected with the flange cover and the flange on the periphery of the manhole 100 by the same set of bolts. The support frame 12 extends relative to the fixing seat 11 to the outside away from the manhole 100, forming a support surface to support the connection winding mechanism 20.

[0036] In some embodiments, the support frame 12 may include a support plate and two side plates connected to opposite sides of the support plate, and the winding mechanism 20 is fixedly connected to the support plate and located between the two side plates.

[0037] In some embodiments, reference Figures 2 to 4 The winding mechanism 20 may include two take-up plates 21, a take-up drum 22, and a drive motor 24. The two take-up plates 21 are arranged opposite to each other, and a winding space is defined therebetween. The take-up drum 22 is arranged in the winding space and is rotatably connected to the take-up plates 21 through a rotating shaft 23. The flat cable 40 is wound on the outer periphery of the take-up drum 22, and the take-up drum 22 rotates forward and reversely to release or reel in the cable. The drive motor 24 is connected to and drives the rotating shaft 23 to rotate.

[0038] The drive motor 24 is preferably a high-efficiency brushless motor. The take-up reel 22 is made of low-friction material, including but not limited to polytetrafluoroethylene sheet, to reduce wear when the flat cable 40 is wound.

[0039] The winding mechanism 20 may also include an electromagnetic brake 25, which is connected in series with the drive motor 24 through the rotating shaft 23 to play a safety role. In one embodiment, the rotating shaft 23 is arranged in the center of the take-up reel 22, and the two ends of the rotating shaft 23 are also connected to the two take-up plates 21. The drive motor 24 is located at one end of the rotating shaft 23 and connected to the rotating shaft 23, and the electromagnetic brake 25 is located at the other end of the rotating shaft 23 and connected to the rotating shaft 23.

[0040] The electromagnetic brake 25 is connected to the control system to achieve remote monitoring and emergency braking.

[0041] In some embodiments, the winding mechanism 20 may further include a first stop gear (not shown) and an anti-falling assembly 26. The first stop gear is coaxially connected to the rotating shaft 23, and when the first stop gear is braked, the rotating shaft 23 is also braked. The anti-falling assembly 26 is arranged on the take-up plate 21 and meshes with the first stop gear. The anti-falling assembly 26 has a braking function, so that the rotating shaft 23 and the take-up reel 22 can be braked by the first stop gear, thereby limiting the release of the flat cable 40 from the winding mechanism 20.

[0042] The anti-fall component 26 may further include a shell 261 fixed on the take-up plate 21, a centrifugal ratchet shaft 262 arranged in the shell 261 and rotatable relative to the shell 261, a ratchet 263 sleeved on the outer periphery of the centrifugal ratchet shaft 262 and fixedly connected to the shell 261, a pawl 264 eccentrically arranged on the centrifugal ratchet shaft 262, and a second stop gear coaxially arranged on the centrifugal ratchet shaft 262; the second stop gear is meshed with the first stop gear.

[0043] The housing 261 may be cylindrical and fixedly connected to the outer surface of the take-up plate 21. One end of the centrifugal ratchet shaft 262 is rotatably connected to the take-up plate 21, and the other end is located in the housing 261 and is rotatable relative to the housing 261. The pawl 264 is arranged on the end surface of the centrifugal ratchet shaft 262 in the housing 261, and can swing back and forth between a first position and a second position relative to the housing 261 as the centrifugal ratchet shaft 262 rotates. In the first position, the end of the pawl 264 is inserted between the teeth of the ratchet 263 (forming a meshing state); in the second position, the end of the pawl 264 is disengaged from the teeth of the ratchet 263. When the pawl 264 is inserted between the teeth of the ratchet 263, the rotation of the centrifugal ratchet shaft 262 is braked, and then the first stop gear and the take-up disk 22 linked thereto are braked through the second stop gear.

[0044] Preferably, two ratchet pawls 264 are provided, which are arranged on the end surface of the centrifugal ratchet shaft 262 away from the take-up plate 21 and are centrally symmetrical about the center of the centrifugal ratchet shaft 262. A limit pin 265 is also provided on the side of each ratchet 264 facing the other ratchet pawl 264. The limit pin 265 is convexly arranged on the end surface of the centrifugal ratchet shaft 262 to limit the swing amplitude of the ratchet 264 and avoid interference between the two ratchet pawls 264 due to swinging.

[0045] Specifically, the pawl 264 is rotationally connected to the end face of the centrifugal ratchet shaft 262 and the rotation of the pawl 264 needs to overcome a certain resistance. When the rotation speed of the centrifugal ratchet shaft 262 is too fast (exceeding the set threshold), the pawl 264 is thrown out and engages with the ratchet 263, and is braked by the ratchet 263, thereby braking the centrifugal ratchet shaft 262, the second stop gear and the first stop gear, and the take-up reel 22, thereby preventing the flat cable 40 from being entangled and the camera unit 50 from falling.

[0046] The anti-fall assembly 26 may further include a speed sensor for monitoring the rotation speed of the centrifugal ratchet shaft 262 in real time and triggering the pawl 264 to brake when the rotation speed exceeds a safety threshold.

[0047] The anti-falling assembly 26 provides safety protection for the winding mechanism 20. When the video inspection device of the present invention has both the anti-falling assembly 26 and the electromagnetic brake 25, the two provide double safety protection.

[0048] like Figure 1 and Figure 5 As shown, the bracket 30 is located on the other side of the supporting mechanism 10 opposite to the winding mechanism 20 .

[0049] Preferably, the end of the bracket 30 away from the supporting mechanism 10 is located at the central axis of the voltage stabilizer, so that the suspended camera unit 50 is located at the central axis of the voltage stabilizer and can move up and down along the central axis of the voltage stabilizer. The up and down movement of the camera unit 50 in the voltage stabilizer is mainly achieved by releasing or retracting the flat cable 40.

[0050] In some embodiments, the bracket 30 may specifically include at least one support rod 31, the first end of the support rod 31 is fixed to the support mechanism 10, and the opposite second end extends toward the central axis of the voltage stabilizer. The support mechanism 10 may further be provided with a guide sleeve, and the first end of the support rod 31 may extend into the guide sleeve and be fixed.

[0051] The bracket 30 preferably includes at least two support rods 31 to improve the support strength.

[0052] Specifically, the first end of the support rod 31 can be connected to the support frame 12 of the support mechanism 10 and fastened, and the second end of the support rod 31 is provided with a reversing assembly for the flat cable 40 to wrap around and pass through. The reversing assembly guides the extension direction of the flat cable 40. The reversing assembly can specifically include a wheel frame 32 and a reversing roller 33 rotatably arranged on the wheel frame 32. The wheel frame 32 can be in a gate shape or an I-shape, etc., and is fixed to the end of the second end of the support rod 31 by fasteners, limit sleeves, etc. There can be one, two or more reversing rollers 33.

[0053] The flat cable 40 extends along the support rod 31 and bypasses the reversing roller 33 , and then extends downward after bypassing the reversing roller 33 . The camera unit 50 is connected to the end of the flat cable 40 , and the flat cable 40 plays a role in traction, power supply and signal transmission for the camera unit 50 .

[0054] The flat cable 40 is flat and has a strong anti-twisting function. Various signal lines are arranged in parallel inside the flat cable 40 .

[0055] Structurally, reference Figure 6 The flat cable 40 includes a high-definition video wire 41 for transmitting video, a cable group, a flexible shaft 45, and a sheath 46, wherein the sheath 46 is wrapped around the outer periphery of the high-definition video wire 41, the cable group, and the flexible shaft 45. In the sheath 46, the high-definition video wire 41 is in the middle position, a plurality of cables of the cable group are distributed on opposite sides of the high-definition video wire 41, and the flexible shaft 45 is arranged at the outermost side of the cable group.

[0056] On each side of the high-definition video cable 41, the cables are backed up by each other, and the multiple cables are arranged in descending order according to their diameters, namely, a power supply cable 42 for transmitting power, a redundant backup cable 43, and a bus signal cable 44 for transmitting control signals. As an option, the power supply cable 42 is 0.75mm 2 Cable, bus signal cable 44 is 0.25mm 2 Cable.

[0057] The camera unit 50 is suspended inside the voltage stabilizer for inspection. The camera of the camera unit 50 has two degrees of freedom of pitch and rotation, both driven by servo motors, to achieve a full range of inspection inside the voltage stabilizer. The camera is designed with a radiation shield and automatic cleaning function.

[0058] By utilizing the flat cable to move up and down along the center axis of the voltage stabilizer under the traction of the retracting and releasing device, a high-definition camera is suspended to perform all-round rotating scanning, thereby achieving the purpose of safe and reliable inspection of the welding layer on the inner surface of the voltage stabilizer.

[0059] The method for using the video inspection device for a nuclear power plant pressurizer according to an embodiment of the present invention for video inspection of the internal weld overlay layer of the pressurizer is as follows:

[0060] Installation: Install the fixing seat 11 on the manhole of the voltage stabilizer, and fasten the fixing seat 11 to the manhole surface with nylon fixing bolts. Install and fix the support frame 12 to the fixing seat 11 and tightly fit with the flange and the manhole flange through the fixing bolts. Install the winding mechanism 20 on the support frame 12, and the winding mechanism 20 and the support frame 12 are fixed by a quick locking structure, and the winding mechanism 20 and the support frame 12 are fastened together with the quick locking structure. Assemble the camera unit 50 and the flat cable 40 together. Pass the flat cable 40 around the reversing roller 33 at the end of the bracket 30, and suspend the camera inside the voltage stabilizer cylinder so that the up and down movement trajectory of the flat cable 40 coincides with the axis of the voltage stabilizer cylinder.

[0061] Startup inspection: The winding mechanism 20 is started, driving the flat cable 40 to move up and down. The up and down movement of the flat cable 40, the rotation of the camera of the camera unit 50, and the pitch movement are combined to complete the video inspection of the surfacing layer on the inner surface of the stabilizer.

[0062] The video inspection device for a nuclear power plant voltage regulator of the present invention is easy to assemble and disassemble, and can effectively reduce the risks of external exposure and body surface contamination; by adopting an integrated design, the number of fasteners can be reduced by 90%, and the risk of foreign matter introduction is eliminated at the source; by adopting a "bus" control mode, the cable connector has only 5 cores (one coaxial line for transmitting video, two power lines for transmitting power, and 2 signal lines for transmitting control signals), which effectively reduces the equipment failure rate and improves the system stability; it has strong versatility and is adaptable to various reactor types in nuclear power plants, can reduce the number of equipment manufactured and the investment in contaminated equipment, and is highly economical.

[0063] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A video inspection device for a nuclear power plant voltage regulator, characterized in that: It includes a support mechanism for positioning at a manhole of a voltage stabilizer, a winding mechanism for retracting and releasing a flat cable, a bracket for extending into the voltage stabilizer, a camera unit for inspection, and a flat cable; The winding mechanism is arranged on a side of the supporting mechanism facing the outside of the voltage stabilizer, and the bracket is arranged on a side of the supporting mechanism facing the inside of the voltage stabilizer; the flat cable is wound on the winding mechanism and the end thereof is connected to the camera unit; After being unwound from the winding mechanism, the flat cable is laid along the length direction of the bracket, so that the camera unit is suspended below the bracket to inspect the surfacing layer on the inner surface of the voltage stabilizer.

2. The video inspection device for a nuclear power plant pressurizer according to claim 1, characterized in that: One end of the bracket away from the supporting mechanism is located at the central axis of the stabilizer, so that the suspended camera unit is located at the central axis of the stabilizer and can move up and down along the central axis of the stabilizer.

3. The video inspection device for a nuclear power plant pressurizer according to claim 1, characterized in that: The flat cable is flat in shape, and a variety of signal lines are arranged in parallel inside the flat cable.

4. The video inspection device for a nuclear power plant pressurizer according to claim 3, characterized in that: The flat cable comprises a high-definition video wire, a cable group, a flexible shaft and a sheath, wherein the sheath is coated on the periphery of the high-definition video wire, the cable group and the flexible shaft; In the outer skin, the high-definition video cable is located in the middle position, a plurality of cables of the cable group are distributed on opposite sides of the high-definition video cable, and the flexible shaft is arranged at the outermost side of the cable group.

5. The video inspection device for a nuclear power plant pressurizer according to claim 1, characterized in that: The winding mechanism comprises two oppositely arranged take-up plates, a take-up reel, a first anti-rotation gear and an anti-falling assembly; A winding space is defined between the two wire-taking plates, the wire-taking drum is arranged in the winding space and is rotatably connected to the wire-taking plates via a rotating shaft; the first anti-rotation gear is coaxially connected to the rotating shaft, and the anti-falling component is arranged on the wire-taking plate and meshes with the first anti-rotation gear.

6. The video inspection device for a nuclear power plant pressurizer according to claim 5, characterized in that: The anti-falling assembly includes a housing fixed on the take-up plate, a centrifugal ratchet shaft arranged in the housing and rotatable relative to the housing, a ratchet sleeved on the outer periphery of the centrifugal ratchet shaft and fixedly connected to the housing, a ratchet pawl eccentrically arranged on the centrifugal ratchet shaft, and a second anti-rotation gear coaxially arranged on the centrifugal ratchet shaft; the second anti-rotation gear is meshed with the first anti-rotation gear; The pawl rotates with the centrifugal ratchet shaft and is used to be inserted between the gear teeth of the ratchet to brake the rotation of the centrifugal ratchet shaft, and then brakes the first anti-rotation gear and the take-up disk linked thereto through the second anti-rotation gear.

7. The video inspection device for a nuclear power plant pressurizer according to claim 6, characterized in that: There are two ratchet claws, which are arranged on the end surface of the centrifugal ratchet shaft away from the take-up plate and are centrally symmetrical about the center of the centrifugal ratchet shaft; A limit pin is also provided on one side of each pawl facing the other pawl. The limit pin is protrudingly arranged on the end surface of the centrifugal ratchet shaft and is used to limit the swing amplitude of the pawl.

8. The video inspection device for a nuclear power plant pressurizer according to claim 5, characterized in that: The winding mechanism also includes a driving motor connected to and driving the rotating shaft to rotate, and an electromagnetic brake connected in series with the driving motor through the rotating shaft.

9. The video inspection device for a nuclear power plant pressurizer according to any one of claims 1 to 8, characterized in that: The support mechanism comprises a fixing seat used to cooperate with the inner wall of the manhole of the voltage stabilizer and be locked at the manhole, and a support frame connected to the fixing seat; the winding mechanism is fixedly connected to the support frame.

10. The video inspection device for a nuclear power plant pressurizer according to claim 9, characterized in that: The bracket includes at least one support rod, a first end of the support rod is fixed to the support mechanism, and an opposite second end extends toward the central axis of the stabilizer; A reversing assembly for the flat cable to wrap around and pass through is disposed on the second end of the bracket; the reversing assembly comprises a wheel frame and a reversing roller rotatably disposed on the wheel frame.

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