A device and method for remote non-destructive testing of pressurized water reactor in-core bolts

Abstract

The application provides a device and method for remote nondestructive testing of a pressurized water reactor in-core bolt, which comprises an ultrasonic probe, a positioning support unit, a feeding motion unit and an operating rod quick insertion connection unit. The ultrasonic probe is located at the bottom of the feeding motion unit and is used for emitting ultrasonic waves and collecting and recording relevant defect signals of the support column fixing bolt. The positioning support unit is located at the side of the feeding motion unit and is used for preliminarily positioning the water inlet hole around the support column fixing bolt. The operating rod quick insertion connection unit is located at the top of the feeding motion unit and is used for being connected with and fixed to the operating rod. The operating rod is used for controlling the movement and rotation of the ultrasonic probe through the feeding motion unit. According to the structural characteristics of the pressurized water reactor in-core support column fixing bolt, the application designs a safe and accurate inspection process method and equipment support, so as to solve the problem of detecting the bolt on the lower core plate of the nuclear power plant pressurized water reactor which is high-irradiation, long-distance and underwater.

Description

Technical Field

[0001] This application belongs to the field of non-destructive testing technology, specifically relating to a device and method for remote non-destructive testing of bolts inside a pressurized water reactor. Background Technology

[0002] The internal components of a pressurized water reactor (PWR) in a nuclear power plant are the core of the reactor. Among them, the bolts on the bottom plate of the core at the bottom of the cradle, used to fix the support columns, work with the columns to provide fixation and support. After prolonged nuclear irradiation and water flow impact, especially when the lower locking nuts loosen, the natural frequency of the support columns of the cradle components is disrupted, leading to a further increase in flow-induced vibration loads. This results in wear, deformation, or breakage of some bolts, further affecting the support strength of adjacent plates and the insertion of neutron flux tubes.

[0003] Therefore, the bolts fixing the support column need to be inspected regularly, and bolts that are deformed, worn, or broken should be disassembled and replaced.

[0004] Taking the fixing bolts of the support column of a 300,000-unit nuclear power plant basket assembly as an example, such as Figure 1 and Figure 2 As shown, the pressure vessel's core bottom plate 10 is equipped with support column fixing bolts 20 (also referred to as bolts for fixing support columns). These bolts are irregularly distributed on the core bottom plate 10 at the bottom of the lifting basket. Each support column fixing bolt 20 has an internal hexagonal head structure, with a conical bottom surface at the head of the hexagonal hole. After installation, the support column fixing bolts 20 are screwed into the internal threaded holes, with only the head of the bolt visible. To prevent the support column fixing bolts 20 from breaking or falling off, anti-loosening pins 30 are designed at the head of the bolts and welded to the core bottom plate 10. The circumferential angles of these anti-loosening pins 30 vary, which can pose some difficulties during inspection.

[0005] Traditional inspection methods primarily employ underwater television inspection, which involves visually examining the surface to determine the scope and number of bolts requiring replacement. This method has limitations; it only observes the surface condition of bolts, fastening pins, and welds, failing to provide a comprehensive and accurate understanding of the bolts' true condition. Furthermore, with a base plate diameter exceeding three meters and dozens of support column fastening bolts in various locations, precise bolt inspection is impossible with limited personnel and simple tools. Summary of the Invention

[0006] Therefore, the application provides a device and method for remote non-destructive testing of a pressurized water reactor in-core bolt, which is designed according to the structural characteristics of the pressurized water reactor in-core support column fixing bolt to solve the problem of detecting the bolt on the lower core plate surface in a nuclear power plant pressurized water reactor with high irradiation, long distance and underwater.

[0007] The first aspect of the application provides a device for remote non-destructive testing of a pressurized water reactor in-core bolt, which comprises an ultrasonic probe, a positioning support unit, a feeding motion unit and an operating rod quick insertion connection unit. The ultrasonic probe is located at the bottom of the feeding motion unit and is used to emit ultrasonic waves and collect and record the relevant defect signals of the support column fixing bolt. The positioning support unit is located at the side of the feeding motion unit and is used to preliminarily position the water inlet hole around the support column fixing bolt. The operating rod quick insertion connection unit is located at the top of the feeding motion unit and is used to be connected and fixed with the operating rod. The operating rod is used to control the movement and rotation of the ultrasonic probe through the feeding motion unit.

[0008] In one specific embodiment of the application, the operating rod quick insertion connection unit comprises a support rod joint, a rotating operating rod joint and a downward operating rod joint. The operating rod comprises a support rod, a rotating operating rod and a downward operating rod. The support rod joint is used to be connected and fixed with the support rod. The rotating operating rod joint is used to be connected and fixed with the rotating operating rod. The downward operating rod joint is used to be connected and fixed with the downward operating rod. The downward operating rod is used to drive the ultrasonic probe to move downward when operated. The rotating operating rod is used to drive the ultrasonic probe to rotate through the feeding motion unit when operated.

[0009] In one specific embodiment of the application, the positioning support unit comprises a positioning column and a support column. The positioning column is used to realize positioning with the ultrasonic probe. The support column is used to be in contact with the lower core plate surface.

[0010] In one specific embodiment of the application, the feeding motion unit comprises a fixing clamp, a compression spring, a gear mechanism, a connecting sleeve and a sleeve. The fixing clamp is connected to the connecting sleeve through threads, and the ultrasonic probe is clamped by the fixing clamp and fixed with the connecting sleeve. The connecting sleeve and the compression spring are placed in the sleeve and can move up and down along the axial direction of the sleeve. The gear mechanism is fixed to the upper end of the sleeve through screws. The compression spring is used to tightly fit the ultrasonic probe carried by the fixing clamp with the inner wall of the center cone hole of the support column fixing bolt.

[0011] In one specific embodiment of the application, the device for remote non-destructive testing of a pressurized water reactor in-core bolt further comprises a mechanical frame. The mechanical frame is arranged outside the feeding motion unit and is used to protect the feeding motion unit.

[0012] In one specific embodiment of the present application, the mechanical frame comprises a bottom plate, a side stand, a first upper top plate, a second upper top plate and a rear stand. The bottom plate, the side stand, the first upper top plate, the second upper top plate and the rear stand are connected by screws to form a frame for supporting the positioning support unit, the feeding motion unit and the operating lever quick plug-in connection unit.

[0013] The second aspect of the present application provides a method for remote non-destructive testing of a pressurized water reactor in-core bolt, which comprises the following steps S1 to S4.

[0014] In step S1, before underwater detection, the operating lever is connected to and fixed with the operating lever quick plug-in connection unit.

[0015] In step S2, under the assistance of underwater television, the positioning support unit is preliminarily positioned to the water inlet hole around the support column fixing bolt.

[0016] In step S3, after the preliminary positioning is completed, the movement and rotation of the ultrasonic probe are controlled by moving and rotating the operating lever to compensate for the positioning error, until the top of the ultrasonic probe and the bottom hole of the center of the support column fixing bolt are fitted, and the ultrasonic probe is tightly attached to the conical surface of the bottom hole of the center of the support column fixing bolt.

[0017] In step S4, the ultrasonic probe is used to scan vertically downward from the inner wall of the center hole of the support column fixing bolt to realize full-volume ultrasonic inspection of the thread area and the polished rod area of the support column fixing bolt, and the related defect signals are collected and recorded by the external encoder.

[0018] In one specific embodiment of the present application, step S3 comprises steps S31 to S33.

[0019] In step S31, the ultrasonic probe is moved downward by moving the operating lever downward, and when the ultrasonic probe approaches the bolt head of the support column fixing bolt, the rotating operating lever is operated to rotate the ultrasonic probe through the gear mechanism in the feeding motion unit, so that the groove of the ultrasonic probe is aligned with the circumferential angle of the anti-loosening pin.

[0020] In step S32, the ultrasonic probe is further moved downward until the top of the ultrasonic probe and the center bottom hole of the in-core support column fixing bolt are fitted.

[0021] In step S33, the ultrasonic probe is tightly attached to the conical surface of the center bottom hole of the in-core support column fixing bolt by continuing to move the operating lever downward to compress the spring.

[0022] The beneficial effects of the technical scheme of the application are as follows: according to the structural characteristics of the fixed bolt of the support column in the reactor core of the pressurized water reactor, a nondestructive testing device for detecting the actual situation of the fixed bolt of the support column on the lower bottom plate of the reactor core is designed, the operation rod quick insertion connection unit connected with the operation rod and fixed is arranged, the conventional inspection of the fixed bolt of the support column on the bottom plate of the hanging basket under the high irradiation, long distance and underwater of the nuclear power pressurized water reactor is met, the positioning support unit is arranged to preliminarily position the water inlet hole around the fixed bolt of the support column, the ultrasonic probe is accurately positioned on the bottom hole taper surface at the center of the fixed bolt of the support column through the joint action of the feeding motion unit and the operation rod, so that the actual situation of the fixed bolt of the support column can be safely and accurately confirmed by the ultrasonic probe, and the inspection accuracy and speed are improved. The embodiment of the application solves the problem of detecting the fixed bolt on the lower bottom plate of the reactor core, has high detection accuracy, is far away from the high irradiation environment to the maximum extent, and greatly reduces the irradiation dose of the operator. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 Fig. 1 is a structural schematic diagram of the fixed bolt of the support column of the hanging basket assembly of a certain nuclear power 300,000 reactor.

[0024] Figure 2 Fig. 2 is a structural schematic diagram of the anti-loosening pin.

[0025] Figure 3 Fig. 3 is a structural schematic diagram of the device for remotely nondestructively testing the fixed bolt in the reactor core of the pressurized water reactor provided by an embodiment of the application.

[0026] Figure 4 Fig. 4 is a flowchart of the method for remotely nondestructively testing the fixed bolt in the reactor core of the pressurized water reactor provided by an embodiment of the application.

[0027] Figure 5 Fig. 5 is a simplified flowchart of the method for remotely nondestructively testing the fixed bolt in the reactor core of the pressurized water reactor provided by an embodiment of the application.

[0028] In the figure, 10 is a reactor core lower bottom plate, 20 is a support column fixed bolt, 30 is an anti-loosening pin;

[0029] 1, ultrasonic probe;

[0030] 2, mechanical frame, 21 is a bottom plate, 22 is a side stand, 23 is a first upper top plate, 24 is a second upper top plate, 25 is a rear stand;

[0031] 3, positioning support unit, 31 is a positioning column, 32 is a support column;

[0032] 4, feeding motion unit, 41 is a fixed clamp, 42 is a compression spring, 43 is a gear mechanism, 44 is a connecting sleeve, 45 is a sleeve;

[0033] 5, operating rod quick plug connection unit, 51, support rod joint, 52, rotating operating rod joint, 53, lower operating rod joint. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0035] At least one embodiment of the present application provides a device for remote nondestructive testing of a pressurized water reactor in-core bolt, which refers to Figure 3 The device for remote nondestructive testing of the pressurized water reactor in-core bolt comprises an ultrasonic probe 1, a positioning support unit 3, a feeding motion unit 4 and an operating rod quick plug connection unit 5. The ultrasonic probe 1 is located at the bottom of the feeding motion unit 4, used for emitting ultrasonic waves and collecting and recording relevant defect signals of a support column fixing bolt 20. The positioning support unit 3 is located at the side of the feeding motion unit 4, used for preliminarily positioning water inlet holes around the support column fixing bolt 20. The operating rod quick plug connection unit 5 is located at the top of the feeding motion unit 4, used for being connected with and fixed to an operating rod. The operating rod is used for controlling the movement and rotation of the ultrasonic probe 1 through the feeding motion unit 4.

[0036] It should be noted that four water inlet holes with fixed distances around the support column fixing bolt 20 can be pre-provided. The support column fixing bolt 20 can be a bolt used for fixing a support column of a bottom plate of an in-core basket. The ultrasonic probe 1 can be referred to as a probe.

[0037] According to the structural characteristics of the pressurized water reactor in-core support column fixing bolt 20, an embodiment of the present application designs a nondestructive testing device specially used for testing the actual situation of the support column fixing bolt 20 on the lower core plate 10. The operating rod quick plug connection unit 5 used for being connected with and fixed to the operating rod is provided, so that the conventional inspection of the support column fixing bolt 20 on the basket bottom plate under the conditions of high irradiation, long distance and underwater of the nuclear power pressurized water reactor is met. The positioning support unit 3 is provided to preliminarily position the ultrasonic probe 1 to the water inlet holes around the support column fixing bolt 20. The feeding motion unit 4 and the operating rod are jointly used to accurately position the ultrasonic probe 1 to the bottom hole cone surface at the center of the support column fixing bolt 20, so that the actual situation of the support column fixing bolt 20 can be safely and accurately confirmed by the ultrasonic probe 1, and the inspection accuracy and speed are improved. The embodiment of the present application solves the problem of detecting the support column fixing bolt 20 on the lower core plate 10, has high detection accuracy, is far away from the high irradiation environment to the maximum extent, and greatly reduces the irradiation dose of the operator.

[0038] In at least one embodiment of the present application, the operating rod quick plug-in connection unit 5 comprises a support rod joint 51, a rotating operating rod joint 52, and a downward operating rod joint 53. The support rod joint 51 is used to connect and fix with the support rod. The rotating operating rod joint 52 is used to connect and fix with the rotating operating rod. The downward operating rod joint 53 is used to connect and fix with the downward operating rod. The downward operating rod is used to drive the ultrasonic probe 1 to move downward. The rotating operating rod is used to drive the ultrasonic probe 1 to rotate through the feeding motion unit 4.

[0039] The operating rod quick plug-in connection unit 5 provided by the embodiments of the present application provides a quick installation interface for the support rod, the rotating operating rod, and the downward operating rod, and can be interchanged with the operating rods of other underwater long rod tools, which provides a possibility for the standardization of the connecting rods and operating rods used by the in-pile underwater operation tools in the future.

[0040] In at least one embodiment of the present application, the positioning support unit 3 comprises a positioning column 31 and a support column 32. The positioning column 31 is used to realize positioning with the ultrasonic probe 1. The support column 32 is used to realize surface contact with the lower core plate 10.

[0041] For example, the number of the positioning column 31 can be 2.

[0042] In at least one embodiment of the present application, the feeding motion unit 4 comprises a fixed clamp 41, a compression spring 42, a gear mechanism 43, a connecting sleeve 44, and a sleeve 45. The fixed clamp 41 is connected to the connecting sleeve 44 through threads, and the ultrasonic probe 1 is clamped by the fixed clamp 41 and fixed to the connecting sleeve 44. The connecting sleeve 44 and the compression spring 42 are placed in the sleeve 45 and can move up and down along the axial direction of the sleeve 45. The gear mechanism 43 is fixed to the upper end of the sleeve 45 through screws. The compression spring 42 is used to tightly fit the ultrasonic probe 1 carried by the fixed clamp 41 with the inner wall of the center tapered hole of the support column fixing bolt 20.

[0043] It should be noted that the connecting sleeve 44 and the sleeve 45 are left with a certain fitting gap to compensate for the error of the initial positioning. By rotating the support rod joint 51, the gear mechanism 43 is driven to rotate, thereby driving the ultrasonic probe 1 to rotate.

[0044] The embodiments of the present application realize the motion mechanism of the ultrasonic probe 1 moving downward and rotating through the gear mechanism 43 and the operating rod, which is simple to operate and can reliably realize the accurate clamping of the ultrasonic probe 1 with the U-shaped groove into the anti-loose pin 30, realize the fitting of the conical surface of the ultrasonic probe 1 with the conical surface of the center bottom hole of the head of the support column fixing bolt 20, and improve the accuracy of the detection process.

[0045] In at least one embodiment of the present application, the device for remote nondestructive testing of in-pile bolts of a pressurized water reactor further comprises a mechanical frame 2. The mechanical frame 2 is arranged outside the feeding motion unit 4 and is used to protect the feeding motion unit 4.

[0046] In at least one embodiment of the present application, the mechanical frame 2 comprises a bottom plate 21, a side vertical plate 22, a first upper top plate 23, a second upper top plate 24, and a rear vertical plate 25. The bottom plate 21, the side vertical plate 22, the first upper top plate 23, the second upper top plate 24, and the rear vertical plate 25 are connected by screws to form a frame for supporting the positioning support unit 3, the feeding motion unit 4, and the operating rod quick connection unit 5.

[0047] It should be noted that the mechanical frame 2 forms the main frame of the device for remotely and non-destructively detecting the in-core bolt of the pressurized water reactor.

[0048] At least one embodiment of the present application provides a method for remotely and non-destructively detecting the in-core bolt of a pressurized water reactor. Referring to Figure 4 The method for remotely and non-destructively detecting the in-core bolt of the pressurized water reactor comprises the following steps S1 to S4.

[0049] In step S1, before the underwater detection, the operating rod is connected to and fixed with the operating rod quick connection unit 5.

[0050] For example, the support rod is connected to and fixed with the support rod joint 51, the rotating operating rod is connected to and fixed with the rotating operating rod joint 52, and the downward operating rod is connected to and fixed with the downward operating rod joint 53.

[0051] It should be noted that step S1 corresponds to the step of fixing the operating rod of the detection device in Figure 5 .

[0052] In step S2, under the assistance of the underwater television, the positioning support unit 3 is preliminarily positioned to the water inlet holes around the support column fixing bolt 20.

[0053] For example, under the assistance of the underwater television (or in cooperation with the remote video), the support column 32 is in contact with the lower core plate 10, the positioning column 31 of the positioning support unit 3 is cooperated with the water inlet holes (such as four round holes) around the support column fixing bolt 20 on the lower core plate 10, and the position of the support column fixing bolt 20 is preliminarily positioned based on the water inlet holes around the support column fixing bolt 20 on the lower core plate 10 as the reference and the lower core plate 10 as the support surface.

[0054] It should be noted that step S2 corresponds to the step of establishing the positioning base by the positioning column 31 and the support column 32 in cooperation with the underwater television in Figure 5 .

[0055] In step S3, after the preliminary positioning is completed, the movement and rotation of the ultrasonic probe 1 are controlled by the operating rod movement and rotation to compensate for the positioning error, until the top of the ultrasonic probe 1 is in contact with the bottom hole of the center of the support column fixing bolt 20, and the ultrasonic probe 1 is tightly attached to the conical surface of the bottom hole of the center of the support column fixing bolt 20.

[0056] Step S4, using the ultrasonic probe 1 to scan vertically downward from the inner wall of the center hole of the support column fixing bolt 20 to realize full-volume ultrasonic inspection of the threaded area and the polished rod area of the support column fixing bolt 20, and collect and record the relevant defect signals through the external encoder.

[0057] Specifically, the ultrasonic probe 1 is used to emit ultrasonic waves and scan vertically downward from the inner wall of the center hole of the support column fixing bolt 20, so as to realize full-volume ultrasonic inspection of the threaded area and the polished rod area of the support column fixing bolt 20. Then the external encoder receives the radio frequency signal and checks and records the data.

[0058] It should be noted that step S4 corresponds to Figure 5 the step of ultrasonic wave scanning, collecting signals, and recording and evaluating defect signals.

[0059] Through the above specific operation, 300,000 in-pile internal component support column bolts are detected one by one, and the remaining bolts are sequentially operated according to the above steps until all the bolts are checked.

[0060] The embodiment of the application provides a precise positioning process and method for the support column fixing bolt of the lower core plate. For the case that only the bolt head is visible on the lower plate, and the anti-loose pin 30 is welded, and the circumferential angles of the anti-loose pin 30 are different, the precise positioning is facilitated, and the future comprehensive detection of the support column fixing bolt 20 on the lower core plate 10 of the pressurized water reactor has guiding significance.

[0061] In at least one embodiment of the application, step S3 includes steps S31 to S33.

[0062] Step S31, move the ultrasonic probe 1 downward by moving the operation rod downward, and when the ultrasonic probe 1 approaches the bolt head of the support column fixing bolt 20, operate the rotary operation rod again, rotate the ultrasonic probe 1 through the gear mechanism 43 in the feeding motion unit 4, so that the groove (such as a U-shaped groove) of the ultrasonic probe 1 is aligned with the circumferential angle of the anti-loose pin 30.

[0063] It should be noted that step S31 corresponds to Figure 5 the step of moving the downward operation rod to approach the upper surface of the bolt (i.e. the support column fixing bolt 20) head until the probe (i.e. the ultrasonic probe 1) is determined to be in place, and operating the rotary operation rod to align the U-shaped groove of the probe with the pin (i.e. the anti-loose pin 30) until the probe is determined to be aligned.

[0064] Step S32, move the ultrasonic probe 1 downward again until the top of the ultrasonic probe 1 and the center bottom hole of the in-pile support column fixing bolt 20 are in close contact.

[0065] Step S33, continue to operate the moving lever down so that the compression spring 42 tightly attaches the ultrasonic probe 1 to the center bottom hole taper surface of the support column fixing bolt 20.

[0066] It should be noted that step S33 corresponds to Figure 5 the step of moving the probe down and fitting the bolt head taper hole.

[0067] The embodiments of the present application realize precise positioning by the groove and top taper surface on the ultrasonic probe 1 cooperating with the anti-loosening pin 30 and taper hole surface of the support column fixing bolt 20 head.

[0068] It should be noted that the combination manner of each technical feature in the embodiments of the present application is not limited to the combination manner recorded in the embodiments of the present application or the combination manner recorded in the specific embodiments, and all the technical features recorded in the present application can be freely combined or integrated in any manner, unless contradictory to each other.

[0069] As shown in the present application and claims, unless the context clearly indicates otherwise, “one”, “a”, and / or “the” do not specifically refer to the singular, but also include the plural. Generally, the term “comprising” only indicates including the steps and elements explicitly identified, and these steps and elements do not constitute an exclusive list, and the method or device can also include other steps or elements.

[0070] The above only describes the preferred embodiments of the present application and does not limit the present application. Any modification, equivalent replacement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A device for remote non-destructive testing of bolts inside a pressurized water reactor, characterized in that, The device comprises an ultrasonic probe, a positioning support unit, a feeding motion unit and a quick plug connection unit of an operating rod, The ultrasonic probe is located at the bottom of the feeding motion unit and used for emitting ultrasonic waves and collecting and recording signals of defects of the fixing bolt of the support column; the positioning support unit is located at the side of the feeding motion unit and used for preliminarily positioning the water inlet hole around the fixing bolt of the support column; the quick plug connection unit of the operating rod is located at the top of the feeding motion unit and used for being connected with and fixed to the operating rod; the operating rod is used for controlling the movement and rotation of the ultrasonic probe through the feeding motion unit. The quick plug connection unit of the operating rod comprises a support rod joint, a rotating operating rod joint and a downward operating rod joint, the operating rod comprises a support rod, a rotating operating rod and a downward operating rod, the support rod joint is used for being connected with and fixed to the support rod, the rotating operating rod joint is used for being connected with and fixed to the rotating operating rod, and the downward operating rod joint is used for being connected with and fixed to the downward operating rod; the downward operating rod is used for driving the ultrasonic probe to move downward when the downward operating rod is operated; the rotating operating rod is used for driving the ultrasonic probe to rotate through the feeding motion unit when the rotating operating rod is operated. The feeding motion unit comprises a fixing clamp, a compression spring, a gear mechanism, a connecting sleeve and a sleeve; the fixing clamp is connected with the connecting sleeve through screw threads; the ultrasonic probe is clamped by the fixing clamp and fixed to the connecting sleeve; the connecting sleeve and the compression spring are placed in the sleeve and can move up and down along the axial direction of the sleeve; the gear mechanism is fixed to the upper end of the sleeve through a screw; the compression spring is used for tightly adhering the ultrasonic probe carried by the fixing clamp to the inner wall of the center tapered hole of the fixing bolt of the support column.

2. The device for remote non-destructive testing of in-core bolts of a pressurized water reactor according to claim 1, characterized in that, The positioning support unit comprises a positioning column and a support column; the positioning column is used for positioning the ultrasonic probe; and the support column is used for contacting the lower core plate surface.

3. The device for remote non-destructive testing of in-core bolts of a pressurized water reactor according to claim 1 or 2, characterized in that, The device further comprises a mechanical frame, wherein the mechanical frame is arranged outside the feeding motion unit and used for protecting the feeding motion unit.

4. The device for remote non-destructive testing of in-core bolts of a pressurized water reactor according to claim 3, characterized in that, The mechanical frame comprises a bottom plate, a side vertical plate, a first upper top plate, a second upper top plate and a rear vertical plate; the bottom plate, the side vertical plate, the first upper top plate, the second upper top plate and the rear vertical plate are connected through screws to form a frame and used for supporting the positioning support unit, the feeding motion unit and the quick plug connection unit of the operating rod.

5. A method of remote non-destructive testing of pressurized water reactor in-core bolts, characterized in that, The device is used for performing the method for remotely and non-destructively detecting the in-core bolt of a pressurized water reactor, and the method comprises the following steps: In step S1, before water inlet detection, the operating rod is connected with and fixed to the quick plug connection unit of the operating rod; In step S2, under the assistance of underwater television, the positioning support unit is preliminarily positioned to the water inlet hole around the fixing bolt of the support column; In step S3, after the preliminary positioning is completed, the movement and rotation of the ultrasonic probe are controlled by moving and rotating the operating rod to compensate for the positioning error until the top of the ultrasonic probe and the bottom hole in the center of the fixing bolt of the support column are tightly adhered to each other, and the ultrasonic probe is tightly adhered to the tapered surface of the bottom hole in the center of the fixing bolt of the support column; In step S4, the ultrasonic probe is used for vertically scanning downward from the inner wall of the center hole of the fixing bolt of the support column to realize full-volume ultrasonic inspection of the thread area and the light rod area of the fixing bolt of the support column, and the related defect signals are collected and recorded through an external encoder.

6. The method of claim 5, wherein, Step S3 comprises: Step S31, the ultrasonic probe is moved downward by the downward operation of the operation lever, and when the ultrasonic probe approaches the bolt head of the support column fixing bolt, the rotation operation lever is operated again, the ultrasonic probe is rotated by the gear mechanism in the feeding motion unit, so that the groove of the ultrasonic probe is aligned with the circumferential angle of the anti-loose pin; Step S32, the ultrasonic probe is moved downward again until the top of the ultrasonic probe and the center bottom hole of the support column fixing bolt in the stack are fitted; Step S33, continue to operate the moving operation lever to move downward, so that the compression spring tightly adheres the ultrasonic probe to the tapered surface of the center bottom hole of the support column fixing bolt in the stack.

Images