Ultrasonic detection tool for sleeve connecting bolt of reactor internal instrument

Abstract

The invention belongs to the technical field of nondestructive testing equipment, and particularly relates to an ultrasonic testing tool for a reactor internal instrument sleeve connecting bolt. Comprising a hoisting part, an underwater installation part and an underwater detection part, the two ends of the underwater installation part are connected with the hoisting part and the underwater detection part respectively, and the hoisting part, the underwater installation part and the underwater detection part are combined together to form an L-shaped structure. The device has the beneficial effects that a maintainer can remotely install detection equipment at the joint of a peripheral instrument sleeve and a large grillwork plate in a lower reactor internal above a component pool by using a crane in a nuclear island, and ultrasonic detection of four bolts can be completed at the same time through one-time installation; the operation risk is low, and implementation is convenient and fast.

Description

Technical Field

[0001] The invention belongs to the technical field of non-destructive testing equipment, and in particular relates to an ultrasonic testing tool for connecting bolts of instrument casings of in-pile components. Background Art

[0002] Nuclear fuel assemblies and in-core components are placed inside the nuclear reactor of a pressurized water reactor (PWR) nuclear power plant. These components consist of upper and lower in-core components (baskets). Their primary functions include precisely positioning and supporting the core fuel assembly and related components, maintaining precise alignment and guidance between the control rod drive lines and the fuel assembly, forming in-core coolant flow paths, rationally distributing and directing coolant flow to reduce ineffective flow, shielding the pressure vessel and minimizing radiation damage, supporting and guiding in-core neutron flux and temperature measurements, and providing secondary support and cushioning in the event of a core drop.

[0003] During nuclear power plant shutdowns for refueling and maintenance, it's often necessary to remove entire in-core components from the pressure vessel and temporarily store them in a component pool adjacent to the reactor pool. To shield the components from radioactivity, they remain submerged underwater. Four support frames, spaced 90 degrees apart, mate with four supports on the outer circumference of the core support plate of the lower in-core component. Because the in-core component stands approximately 10 meters tall, contains numerous parts, and has a thicker-at-top, thinner-at-the-bottom structure, placing it onto the four support frames in the component pool presents a significant lifting risk. The large grid plate of the lower in-core component could collide with the support frames in the pool. According to nuclear power plant operating incidents reported by nuclear power plant regulatory agencies, such incidents have occurred at certain power plants in China.

[0004] When the grid plate collides with the support frame, the connection structure between the instrument casing and the grid plate, located at the edge of the grid plate, is significantly impacted, potentially causing the four connecting bolts between the two to break. To assess the reliability of the connection between the instrument casing and the grid plate, nondestructive testing of these bolts is required.

[0005] Ultrasonic testing is an effective method for determining whether bolts have cracks. However, because the large grid plate is significantly smaller than the upper in-core component cylinder, the internal instrument casing forms a jungle structure, and there are support frames on all four sides of the large grid plate, there are many obstructions in the space. In addition, the space within the component pool is very limited, and personnel can only operate above the pool, which is more than ten meters away. Under these conditions, using detection tools to conduct inspections at this location carries a high operational risk. On the one hand, it is necessary to avoid collisions between the detection tools and the related structures of the lower in-core component. On the other hand, if the equipment fails during the inspection process, it must be able to be safely withdrawn. Therefore, conventional means cannot perform underwater inspections on the inspection area at the bottom of the component pool.

[0006] To meet such inspection requirements, it is necessary to use a miniaturized inspection tool that can adapt to the special structure of the lower internal components, can be remotely positioned and installed underwater, and has low safety risks, so as to realize ultrasonic inspection of the connecting bolts between the large grid plate of the lower internal components and the instrument casing. Summary of the Invention

[0007] The purpose of the present invention is to provide an ultrasonic detection tool for the connecting bolts of the instrument casing of the reactor internal component, which is miniaturized, adaptable to the jungle structure of the lower internal component, capable of underwater remote positioning and installation, easy to operate, and has low safety risks, so as to realize ultrasonic detection of the connecting bolts between the large frame plate of the lower internal component and the instrument casing.

[0008] The technical solution of the present invention is as follows: an ultrasonic detection tool for connecting bolts of instrument casings of in-pile components, characterized in that it includes a lifting component, an underwater installation component and an underwater detection component, the two ends of the underwater installation component are respectively connected to the lifting component and the underwater detection component, and the lifting component, the underwater installation component and the underwater detection component are combined together to form an L-shaped structure as a whole.

[0009] The hoisting component comprises a hoisting long rod and a hoisting seat. The top of the hoisting long rod comprises a long rod end and a hoisting ring connected thereto. The bottom of the hoisting long rod is connected to the hoisting interface of the hoisting seat.

[0010] The hoisting long pole is a segmented and splicable structure, and different lengths can be obtained by splicing different numbers of single-section long poles.

[0011] The underwater mounting component includes a mounting beam, a connecting base connected and fixed to the mounting beam, a centering cylinder mounting seat and a guide rail fixed on the connecting base, a centering cylinder fixed on the centering cylinder mounting seat, a tail of the positioning fork connected to the front end of the centering cylinder, and a side connected to the guide rail through a slider. When the centering cylinder performs telescopic movement, it can drive the positioning fork to perform telescopic movement. The linear motion pair formed by the slider and the guide rail can provide auxiliary guidance and auxiliary support for the telescopic movement of the positioning fork. The side positioning cylinder is installed below the positioning fork. A side positioning block is installed at the front end of the side positioning cylinder, which can move with the extension and contraction of the side positioning cylinder. Small underwater monitoring cameras are arranged on the front and sides of the connecting base.

[0012] The front end of the positioning fork is an arc-shaped structure, which matches the outer diameter of the instrument casing flange.

[0013] Buoyancy material is embedded in the installation beam.

[0014] The underwater detection component is installed on the positioning fork of the underwater mounting component through the probe fitting cylinder seat. The underwater detection component as a whole can move with the movement of the positioning fork. The probe fitting cylinder is installed on the probe fitting cylinder seat and can telescope upward. The U-shaped plate is installed on the top of the probe fitting cylinder. When the probe fitting cylinder is telescoped up and down, the U-shaped plate can move up and down accordingly. The connecting shaft passes through the U-shaped plate and is connected and fixed to the probe mounting seat. The whole formed by the connecting shaft and the probe mounting seat can move freely up and down relative to the U-shaped plate. A compression spring is inserted between the U-shaped plate and the probe mounting seat. The ultrasonic probe is installed on the probe mounting seat. The lower end face of the probe mounting seat of the probe mounting seat has an opening. Combined with the guide chamfer of the probe mounting seat and the inner cylindrical surface of the probe mounting seat, a bell-shaped guide structure is formed. Two ultrasonic probes are arranged on each underwater detection component. The equipment can complete the detection of four bolts after one installation.

[0015] The beneficial effects of the present invention are that maintenance personnel can use a crane inside the nuclear island to remotely install the detection equipment at the connection between the peripheral instrument casing and the large grid plate in the lower in-core component above the component pool, and ultrasonic testing of four bolts can be completed simultaneously in one installation; the operation risk is low, and the implementation is convenient and fast. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the state of the in-pile components when placed in the component pool (top view);

[0017] Figure 2 Schematic diagram of the state (side view) of the in-pile components when placed in the component pool;

[0018] Figure 3 for Figure 2 A partial enlarged view of

[0019] Figure 4 This is a schematic diagram of the overall structure of an ultrasonic detection tool for connecting bolts of instrument casings of in-core components provided by the present invention;

[0020] Figure 5 This is a schematic diagram of the underwater installation component structure;

[0021] Figure 6 Schematic diagram of the underwater detection component structure Figure 1 ;

[0022] Figure 7 Schematic diagram of the underwater detection component structure Figure 2 ;

[0023] Figure 8 This is a schematic diagram of the initial state of the detection tool before installation;

[0024] Figure 9 for Figure 8 Top partial view;

[0025] Figure 10 for Figure 8 A top view of

[0026] Figure 11 This is a schematic diagram of the detection tool entering the lower pile internals;

[0027] Figure 12 for Figure 11 A top view of

[0028] Figure 13 This is a schematic diagram of the state where the detection tool is located directly behind the casing of the instrument being tested;

[0029] Figure 14 This is a schematic diagram of the state where the detection tool surrounds the casing of the instrument under inspection (side view);

[0030] Figure 15 This is a schematic diagram of the detection tool in position;

[0031] Figure 16 This is a schematic diagram of the detection tool after positioning and installation (before the probe is attached);

[0032] Figure 17 for Figure 16 The partial enlarged view is a schematic diagram showing the state of the probe before bonding;

[0033] Figure 18 This is a schematic diagram of the detection tool detection implementation status (after the probe is attached).

[0034] In the figure: 1 component pool, 2 internal components, 3 support base, 4 detection tool, 5 hand chain hoist, 1001 component pool wall, 1002 component pool bottom, 2001 lower internal components, 4001 lifting components, 4002 underwater installation components, 4003 underwater detection components, 5001 hook, 2001001 support block, 2001002 large grid plate, 2001003 instrument casing, 2001004 connection Connecting bolts, 2001005 hanging basket bottom plate, 4001001 lifting long rod, 4001002 lifting seat, 4002001 connecting beam, 4002002 buoyancy material, 4002003 connecting base, 4002004 centering cylinder mounting seat, 4002005 centering cylinder, 4002006 positioning fork, 4002007 slider, 4002008 guide rail, 4002009 side positioning cylinder, 4002010 side positioning block, 4003001 probe fitting cylinder seat, 4003002 probe fitting cylinder, 4003003 U-shaped plate, 4003004 connecting shaft, 4003005 limit screw, 4003006 compression spring, 4003007 nut, 4003008 probe mounting seat, 4003009 ultrasonic probe, 2001002001 outer side of large grid plate, 2001003 001 instrument casing flange, 2001004001 bolt end outer circle, 2001004002 bolt end inner hole, 4001001001 single-section long rod, 4001001002 long rod end, 4001001003 lifting ring, 4003008001 probe mounting base lower end face, 4003008002 probe mounting base guide chamfer, 4003008003 probe mounting base inner cylindrical surface. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] An ultrasonic detection tool for connecting bolts of instrument casings of reactor internal components comprises a hoisting component, an underwater installation component and an underwater detection component.

[0037] Among them, the lifting components include an operating long pole that can be extended by segmented splicing and a lifting seat. During on-site implementation, the operating long pole is hung on a hand hoist through a lifting ring, and the hand hoist is suspended on a crane hook in the nuclear island. The operating long pole is connected to the lifting port on the lifting seat through a connecting structure, and then the entire detection tool can be lifted by a crane and placed in the component pool for remote installation.

[0038] Because the components inside the pile are larger at the top and smaller at the bottom, when installing the inspection tool, the inspection tool is slowly sent into the water from the gap between the components inside the pile and the component pool wall and lowered to the height of the large grid plate. The long operating rod is then rotated to rotate the part of the inspection tool in the water and adjust its posture, so that the inspection tool enters the "jungle" area where the instrument casing is located and goes around to the back of the instrument casing that needs to be inspected; the height is fine-tuned by using a hand hoist, and the installation and positioning are carried out using underwater installation components, so that the bolts to be inspected are located inside the inspection tool and surrounded by underwater installation components and underwater inspection components.

[0039] The detection tool is positioned at the center of the instrument casing by retracting two positioning forks distributed at 180 degrees toward the center of the instrument casing; the relative direction positioning of the underwater detection component and the connecting bolt is achieved by pulling back and retracting the positioning side plate; the probe is then pressed down by the probe clamping cylinder and guided into the bolt head in conjunction with the guide structure at the front end of the probe mounting seat. Under the joint action of the probe clamping cylinder and the compression spring, the ultrasonic probe is fitted to the connecting bolt head, finally achieving ultrasonic inspection.

[0040] The positioning and installation of the detection tool and the fitting of the probe are all achieved through the extension and retraction of the cylinder, which is convenient for personnel to operate; the "holding", "pressing" and "fitting" of the equipment and the probe are all achieved when the cylinder is extended. Even if the air supply is interrupted, the equipment will not be stuck and cannot be disassembled or recycled, and the equipment can be safely recycled.

[0041] The underwater installation components are equipped with multiple small underwater cameras, which can monitor the remote installation process and facilitate the installers to accurately implement remote installation.

[0042] like Figure 1-3 As shown, the in-core component 2 is taken out of the nuclear reactor pressure vessel during the overhaul of the nuclear power plant and placed in the component pool 1. The distance between the wall 1001 of the construction pool and the in-core component 2 is small. The bottom 1002 of the construction pool is provided with four support seats 3 distributed in a 360° circle. The support seats 3 support the four support blocks 2001001 around the lower in-core component 2001, thereby ensuring that the in-core component 2 is stably stored in the component pool 1. Component 2001 includes instrument sleeves 2001003 distributed according to a certain rule. The instrument sleeves 2001003 are fixed to the large grid plate 2001002 by four evenly distributed connecting bolts 2001004. The interlayer spacing between the hanging basket bottom plate 2001005 and the large grid plate 2001002 is small and there are numerous instrument sleeves 2001003 distributed thereon, forming a "jungle" structure. Some instrument sleeves 2001003 are located just on the inner side of the support seat 3.

[0043] like Figure 4As shown, an ultrasonic detection tool for connecting bolts of instrument casings of in-core components includes a lifting component 4001, an underwater installation component 4002 and an underwater detection component 4003. The two ends of the underwater installation component 4002 are respectively connected to the lifting component 4001 and the underwater detection component 4003, and the overall shape is "L".

[0044] The lifting component 4001 includes a lifting long pole 4001001 and a lifting seat 4001002. The lifting long pole 4001001 is a segmented and splicable structure. By splicing different numbers of single-section long poles 40001001001, different lengths can be obtained to adapt to different height requirements. The top of the lifting long pole 4001001 includes a long pole end 4001001002 and a lifting ring 4001001003 connected thereto, which is used for lifting. The bottom of the lifting long pole 4001001 is connected to the lifting interface 4001002001 of the lifting seat 4001002 and forms a self-operating state, thereby ensuring the connection reliability during the lifting and installation process.

[0045] like Figure 5As shown, the underwater installation component 4002 includes a mounting beam 4002001. The mounting beam 4002001 is long enough to allow the front end structure to be delivered to the vicinity of the instrument casing 2001003 to be inspected without interfering or colliding with the internal components 2 during tool installation. Buoyancy material 4002002 is embedded in the mounting beam 4002001 to balance the gravity of the inspection tool and bring the center of gravity of the entire inspection tool closer to the location of the long hoisting rod 4001001. It is convenient for hoisting operation and underwater installation; the connecting base 4002003 is connected and fixed to the mounting beam 4002001, the centering cylinder mounting base 4002004 and the guide rail 4002008 are fixed on the connecting base 4002003, the centering cylinder 4002005 is fixed on the centering cylinder mounting base 4002004, the tail of the positioning fork 4002006 is connected to the front end of the centering cylinder 4002005, and the side is connected to the guide rail 4002008 through the slider 4002007. When 02005 performs telescopic movement, it can drive the positioning fork 4002006 to perform telescopic movement. The linear motion pair formed by the slider 4002007 and the guide rail 4002008 can provide auxiliary guidance and auxiliary support for the telescopic movement of the positioning fork 4002006, making its movement more stable. The front end of the positioning fork 4002006 is an arc-shaped structure, which matches the outer diameter of the instrument casing flange 2001003001 to achieve installation and positioning. The side positioning cylinder 4002009 is installed on the positioning fork 4002 006, it can move with the positioning fork 4002006, and the front end of the side positioning cylinder 4002009 is equipped with a side positioning block 4002010, which can move with the extension and contraction of the side positioning cylinder 4002009. Small underwater monitoring cameras 4002011 are arranged on the front and sides of the connecting base 4002003, which can monitor and observe the surrounding geometric space and various actions of the detection tool itself during the installation process, so that the operator can implement remote installation more safely and conveniently.

[0046] like Figure 6 and 7As shown, the underwater detection component 4003 is installed on the positioning fork 4002006 of the underwater installation component 4002 through the probe fitting cylinder seat 4003001. The underwater detection component 4003 can move as the positioning fork 4002006 moves. The probe fitting cylinder 4003002 is installed on the probe fitting cylinder seat 4003001 and can perform telescopic movement in the up and down directions. The U-shaped plate 4003003 is installed on the top of the probe fitting cylinder 4003002. When the probe When the head fitting cylinder 4003002 is extended and retracted up and down, the U-shaped plate 4003003 can move up and down accordingly. The connecting shaft 4003004 successively passes through the U-shaped plate 4003003 and is connected and fixed to the probe mounting seat 4003008 by means of a nut 4003007. The whole formed by the connecting shaft 4003004 and the probe mounting seat 4003008 can freely move up and down relative to the U-shaped plate 4003003. There is a plug between the U-shaped plate 4003003 and the probe mounting seat 4003008. Four compression springs 4003006 are evenly distributed in the circumferential direction and are limited by corresponding limit screws 4003005 installed on the U-shaped plate 4003003 to prevent the compression springs 4003006 from falling out. The compression springs 4003006 are always in a compressed state, providing continuous downward pressure to the probe mounting base 4003008. The ultrasonic probe 4003009 is installed in the center of the probe mounting base 4003008 and is exposed to a sufficient length. The probe mounting base 4003008 is The lower end surface 4003008001 of the probe mounting base of 08 has sufficient openings to accommodate the positioning error of the ultrasonic probe 4003009 to a certain extent. Combined with the guide chamfer 4003008002 of the probe mounting base and the inner cylindrical surface 4003008003 of the probe mounting base, a bell-shaped guide structure is formed, which facilitates better positioning and fitting of the ultrasonic probe 4003009 during detection. Two ultrasonic probes 4003009 are arranged on each underwater detection component 4003.

[0047] Figure 8-18 This is an embodiment of the installation and inspection process of the inspection tool 4, and the inspection object is an instrument casing 2001003 located inside one of the support seats 3.

[0048] Figure 8-10 The state shown is the initial state before the detection tool 4 is installed. At this time, the detection tool 4 is located above the in-core component 2. The crane in the nuclear island is connected to the lifting long rod 4001001 through the hook 5001 of the hand hoist 5, thereby driving the detection tool 4 to rise and fall in the construction pool 1. When the detection tool 4 starts to descend, it needs to start descending from the space between the in-core component 2 and the component pool wall 1001 to avoid collision with the in-core component 2.

[0049] like Figure 11 and 12As shown, when the detection tool 4 descends to near the installation height, the operator can slowly push and rotate the lifting long rod 4001001, so that the detection equipment 4 slowly enters from the outer periphery of the lower internal component 2001 to the inner side of the support seat 3, the "jungle" structure between the hanging basket bottom plate 2001005 and the large grid plate 2001002. The entire process is carried out under the auxiliary observation of the small underwater monitoring camera 4002011.

[0050] like Figure 13 As shown, the operator continues to slowly push and rotate the lifting rod 4001001, so that the detection equipment 4 moves to the rear of the instrument casing 2001003 to be inspected, so that positioning and installation can be carried out through the underwater installation component 4002. The whole process is carried out under the auxiliary observation of the small underwater monitoring camera 4002011. In order to facilitate the reflection of the relevant status, the support column 3 at this location is hidden in this figure.

[0051] Figure 14 for Figure 13 A close-up measurement view of the state shown shows that the centering cylinder 4002005 on the underwater mounting component 4002 is in a retracted state, the side positioning cylinder 4002009 is in an extended state, the probe fitting cylinder 4003001 on the underwater detection component 4003 is in an upwardly extended state, and the instrument casing 2001003 to be inspected is located between the two centering cylinders 4002005 arranged at 180 degrees.

[0052] exist Figure 13 Based on the state shown, the operator fine-tunes the height of the detection tool 4 underwater by adjusting the hand hoist 5, and finally makes the detection tool 4 fall on the large grid plate 2001002, forming Figure 15 Status shown.

[0053] exist Figure 15 Based on the state shown, the two centering cylinders 4002005 can be extended at this time, so that the two positioning forks 4002006 simultaneously embrace the instrument casing flange 2001003001, and then the side positioning cylinder 4002009 is retracted, so that the side positioning block 4002010 is close to the outer side surface 2001002001 of the large grid plate. At this time, a positioning relationship is formed between the detection tool 4 and the instrument casing 2001003 to be detected in both the circular and circumferential directions. At this time, the ultrasonic probe 4003009 is basically aligned with the connecting bolt 2001004, forming a Figure 16 In the state shown, the detection tool 4 is in the inspection state.

[0054] Figure 17 yes Figure 16The enlarged detail view of the state shown shows that when the ultrasonic probe 4003009 needs to be fitted with the connecting bolt 2001004, the probe fitting cylinder 4003002 contracts downward, and under the mutual guiding action between the lower end surface 4003008001 of the probe mounting base, the guide chamfer 4003008002 of the probe mounting base, the inner cylindrical surface 4003008003 of the probe mounting base and the outer circle 2001004001 of the bolt end, as well as the continuous pressure exerted by the compression spring 4003006 on the probe mounting base 4003008, the ultrasonic probe 4003009 is sent into the inner hole 2001004002 of the bolt end, thereby achieving probe fitting, and then ultrasonic testing of the connecting bolt 2001004 can be carried out.

[0055] Figure 18 This is a schematic diagram of the status of the entire detection tool 4 when ultrasonic testing is carried out after the probe is attached. To facilitate the display of the relevant status, the support column 3 at this location is hidden in this figure. After the ultrasonic signal is collected, the detection tool 4 can operate in the reverse direction of the above process, withdraw from the in-pile component 2, and finally rise out of the component pool 1, completing the entire detection implementation process.

Claims

1. An ultrasonic testing tool for connecting bolts of instrument casings of reactor internal components, characterized by: It includes a lifting component, an underwater installation component and an underwater detection component. The two ends of the underwater installation component are respectively connected to the lifting component and the underwater detection component. The lifting component, the underwater installation component and the underwater detection component are combined together to form an L-shaped structure.

2. The ultrasonic testing tool for connecting bolts of instrument casings of in-core components according to claim 1, characterized in that: The hoisting component comprises a hoisting long rod and a hoisting seat. The top of the hoisting long rod comprises a long rod end and a hoisting ring connected thereto. The bottom of the hoisting long rod is connected to the hoisting interface of the hoisting seat.

3. The ultrasonic testing tool for connecting bolts of instrument casings of reactor internal components according to claim 2, characterized in that: The hoisting long pole is a segmented and splicable structure, and different lengths can be obtained by splicing different numbers of single-section long poles.

4. The ultrasonic testing tool for connecting bolts of instrument casings of reactor internal components according to claim 1, characterized in that: The underwater mounting component includes a mounting beam, a connecting base connected and fixed to the mounting beam, a centering cylinder mounting seat and a guide rail fixed on the connecting base, a centering cylinder fixed on the centering cylinder mounting seat, a tail of the positioning fork connected to the front end of the centering cylinder, and a side connected to the guide rail through a slider. When the centering cylinder performs telescopic movement, it can drive the positioning fork to perform telescopic movement. The linear motion pair formed by the slider and the guide rail can provide auxiliary guidance and auxiliary support for the telescopic movement of the positioning fork. The side positioning cylinder is installed below the positioning fork. A side positioning block is installed at the front end of the side positioning cylinder, which can move with the extension and contraction of the side positioning cylinder. Small underwater monitoring cameras are arranged on the front and sides of the connecting base.

5. The ultrasonic testing tool for connecting bolts of instrument casings of reactor internal components according to claim 4, characterized in that: The front end of the positioning fork is an arc-shaped structure, which matches the outer diameter of the instrument casing flange.

6. The ultrasonic testing tool for connecting bolts of instrument casings of reactor internal components according to claim 4, characterized in that: Buoyancy material is embedded in the installation beam.

7. The ultrasonic testing tool for connecting bolts of instrument casings of reactor internals according to claim 1, characterized in that: The underwater detection component is installed on the positioning fork of the underwater mounting component through the probe fitting cylinder seat. The underwater detection component as a whole can move with the movement of the positioning fork. The probe fitting cylinder is installed on the probe fitting cylinder seat and can telescope upward. The U-shaped plate is installed on the top of the probe fitting cylinder. When the probe fitting cylinder is telescoped up and down, the U-shaped plate can move up and down accordingly. The connecting shaft passes through the U-shaped plate and is connected and fixed to the probe mounting seat. The whole formed by the connecting shaft and the probe mounting seat can move freely up and down relative to the U-shaped plate. A compression spring is inserted between the U-shaped plate and the probe mounting seat. The ultrasonic probe is installed on the probe mounting seat. The lower end face of the probe mounting seat of the probe mounting seat has an opening. Combined with the guide chamfer of the probe mounting seat and the inner cylindrical surface of the probe mounting seat, a bell-shaped guide structure is formed. Two ultrasonic probes are arranged on each underwater detection component. The equipment can complete the detection of four bolts after one installation.

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