Nondestructive testing method and system for lower end plug of nuclear fuel assembly

Abstract

The invention discloses a nondestructive testing method and system for a lower end plug of a nuclear fuel assembly, and relates to the technical field of nondestructive testing of nuclear energy equipment.The position of a lower tube base positioning camera is adjusted through a six-degree-of-freedom mechanical arm and a linear motion module, and the lower tube base positioning camera is made to directly face a lower tube base of the nuclear fuel assembly to be detected; then, a six-degree-of-freedom mechanical arm is adopted to adjust the position of a pin hole positioning camera, so that the pin hole positioning camera is located below the lower end plug, and a special tool for a spring guide pin is adopted to fix the nuclear fuel assembly to be detected; and finally, the intelligent analysis control module analyzes the third visual media information collected by the endoscopic camera shooting probe group to obtain a nondestructive testing result, manual participation is not needed in the whole nondestructive testing process of the nuclear fuel assembly lower end plug, and a series of problems generated by manual testing are avoided.

Description

Technical Field

[0001] This application relates to the field of non-destructive testing technology for nuclear energy equipment, and in particular to a non-destructive testing method and system for the lower plug of a nuclear fuel assembly. Background Technology

[0002] Nuclear fuel assemblies, as the core carriers of energy release in nuclear power plants, are directly related to the sustainable development of nuclear energy utilization due to their safety. Among them, the lower plug of the nuclear fuel assembly, as a key structure for cladding sealing, plays a crucial barrier role in preventing the leakage of fission products. Statistics show that one of the main causes of most nuclear fuel assembly failures is cladding damage caused by lower plug seal failure or pellet detachment.

[0003] To ensure the safe monitoring of nuclear fuel assemblies throughout the entire lifecycle of a nuclear power plant, prevent nuclear leaks, and avoid major nuclear safety accidents caused by lower plug seal failure or pellet detachment, it is necessary to inspect the appearance integrity of the lower plug before the nuclear fuel assembly enters the reactor. However, current technologies generally rely on manual inspection, which is prone to errors and results in low inspection accuracy. Summary of the Invention

[0004] In view of the above problems, this application provides a non-destructive testing system, method, and related apparatus for the lower end plug of nuclear fuel assemblies, so as to achieve fully automated, non-destructive, and accurate testing of the appearance integrity of the lower end plug. The specific solution is as follows:

[0005] The first aspect of this application provides a non-destructive testing method for the lower end plug of a nuclear fuel assembly, which is applied to an intelligent analysis and control module in a non-destructive testing system for the lower end plug of a nuclear fuel assembly. The non-destructive testing system also includes a six-degree-of-freedom robotic arm, a special tool for spring guide pins mounted on the six-degree-of-freedom robotic arm, a linear motion module and a pin hole positioning camera mounted on the special tool for spring guide pins, and a lower tube seat positioning camera and an endoscope probe group mounted on the linear motion module.

[0006] The methods include:

[0007] First position adjustment information is generated based on the first visual media information collected by the lower tube socket positioning camera; the first visual media information is collected when the lower tube socket of the nuclear fuel assembly to be detected is detected in the current field of view of the lower tube socket positioning camera.

[0008] The six-degree-of-freedom robotic arm is controlled to adjust its position according to the first position adjustment information so that the lower tube seat positioning camera is adjusted to the first target pose; the first target pose is that the optical center of the lower tube seat positioning camera and the lower tube seat of the nuclear fuel assembly to be inspected are on the same vertical line.

[0009] generating second position adjustment information according to second visual media information collected by the pinhole positioning camera, the second visual media information being collected when it is detected that the pinhole positioning camera currently views the lower end plug of the lower nozzle of the nuclear fuel assembly to be detected;

[0010] controlling the six-degree-of-freedom robot to adjust the position according to the second position adjustment information, so that the pinhole positioning camera is adjusted to a second target pose; the second target pose is that the camera optical center of the pinhole positioning camera is on the same vertical line as the lower end plug;

[0011] controlling the spring guide pin special tool to fix the lower nozzle of the nuclear fuel assembly to be detected, and controlling the endoscopic camera probe group to move below the lower end plug to collect third visual media information;

[0012] determining the nondestructive testing result of the lower end plug based on the third visual media information.

[0013] In a possible implementation, the first position adjustment information includes first position adjustment instructions, the first position adjustment information is generated according to first visual media information collected by the lower nozzle positioning camera, and includes:

[0014] analyzing the first visual media information to obtain a first analysis result;

[0015] determining first relative position information of the lower nozzle of the nuclear fuel assembly to be detected based on the first analysis result;

[0016] when the first relative position information indicates that the lower nozzle of the nuclear fuel assembly to be detected is not at a preset first target position, generating first position adjustment instructions and sending the first position adjustment instructions to the six-degree-of-freedom robot.

[0017] In a possible implementation, the second position adjustment information includes second position adjustment instructions, the second position adjustment information is generated according to second visual media information collected by the pinhole positioning camera, and includes:

[0018] analyzing the second visual media information to obtain a second analysis result;

[0019] determining second relative position information of each pin hole in the lower nozzle based on the second analysis result;

[0020] when the second relative position information indicates that each pin hole is not at a preset second target position, generating second position adjustment instructions and sending the second position adjustment instructions to the six-degree-of-freedom robot.

[0021] In a possible implementation, after controlling the spring guide pin special tool to fix the lower nozzle of the nuclear fuel assembly to be detected, and controlling the endoscopic camera probe group to move below the lower end plug to collect third visual media information, before determining the nondestructive testing result of the lower end plug based on the third visual media information, the method further includes:

[0022] receive third visual media information sent by the endoscope camera probe group; the third visual media information is visual media information of the lower end plug collected by the endoscope camera probe group.

[0023] In a possible implementation, based on the third visual media information, the nondestructive detection result of the lower end plug is determined, including:

[0024] inputting the third visual media information into a nondestructive detection model based on a deep convolutional network to obtain the nondestructive detection result.

[0025] In a possible implementation, after the six-degree-of-freedom robot arm is controlled to adjust the position according to the second position adjustment information to make the pin hole positioning camera adjust to the second target pose, before the nondestructive detection result of the lower end plug is determined based on the third visual media information, the method further includes:

[0026] receive fourth visual media information collected by the lower tube seat positioning camera; the fourth visual media information is visual media information of a lower tube seat of the nuclear fuel assembly to be detected;

[0027] When the fourth visual media information indicates that the lower tube seat positioning camera is not at the preset first target position, fourth position adjustment information is generated according to the fourth visual media information to control the six-degree-of-freedom robot arm to adjust the lower tube seat positioning camera to the first target pose according to the fourth position adjustment information.

[0028] The second aspect of the present application provides a nondestructive detection system for a lower end plug of a nuclear fuel assembly, including:

[0029] a six-degree-of-freedom robot arm;

[0030] a spring guide pin special tool mounted on the six-degree-of-freedom robot arm;

[0031] a linear motion module and a pin hole positioning camera mounted on the spring guide pin special tool; the pin hole positioning camera is used to collect second visual media information; the second visual media information is collected when it is detected that the pin hole positioning camera currently includes the lower end plug of the lower tube seat of the nuclear fuel assembly to be detected in the field of view;

[0032] a lower tube seat positioning camera and an endoscope camera probe group mounted on the linear motion module; the lower tube seat positioning camera is used to collect first visual media information; the first visual media information is collected when it is detected that the lower tube seat positioning camera currently includes the lower tube seat of the nuclear fuel assembly to be detected in the field of view;

[0033] The system further comprises an intelligent analysis control module, configured to generate first position adjustment information according to the first visual media information, to control the six-degree-of-freedom robot arm to adjust the position according to the first position adjustment information, so that the lower nozzle positioning camera is adjusted to a first target pose, the first target pose being that the camera optical center of the lower nozzle positioning camera is on the same vertical line as the lower nozzle of the nuclear fuel assembly to be detected; generate second position adjustment information according to the second visual media information collected by the pin hole positioning camera, to control the six-degree-of-freedom robot arm to adjust the position according to the second position adjustment information, so that the pin hole positioning camera is adjusted to a second target pose; the second target pose being that the camera optical center of the pin hole positioning camera is on the same vertical line as the lower end plug; then control the spring guide pin special tool to fix the lower nozzle of the nuclear fuel assembly to be detected, and control the endoscopic camera probe group to move below the lower end plug, collect third visual media information, and determine the non-destructive testing result of the lower end plug based on the third visual media information.

[0034] In a possible implementation, the spring guide pin special tool comprises at least two groups of pins arranged in a diagonal line.

[0035] The intelligent analysis control module inserts the at least two groups of pins into the pin holes of the lower nozzle of the nuclear fuel assembly to be detected by controlling the contact force on the six-degree-of-freedom robot arm.

[0036] In a possible implementation, the linear motion module comprises a moving slider, and the endoscopic camera probe group is installed on the moving slider.

[0037] The intelligent analysis control module controls the moving slider to move the endoscopic camera probe group below the lower end plug.

[0038] In a possible implementation, the non-destructive testing system of the lower end plug of the nuclear fuel assembly further comprises an information exchange module.

[0039] The information exchange module is configured to send the third visual media information collected by the endoscopic camera probe group to the intelligent analysis control module.

[0040] By means of the technical solutions described above, the non-destructive testing method and system of the lower end plug of the nuclear fuel assembly provided in the present application adjust the position of the lower nozzle positioning camera by using the six-degree-of-freedom robot arm and the linear motion module, so that the lower nozzle positioning camera is directly opposite the lower nozzle of the nuclear fuel assembly to be detected; then, the position of the pin hole positioning camera is adjusted by using the six-degree-of-freedom robot arm, so that the pin hole positioning camera is located below the lower end plug, and the nuclear fuel assembly to be detected is fixed by using the spring guide pin special tool; finally, the intelligent analysis control module analyzes the third visual media information collected by the endoscopic camera probe group to obtain the non-destructive testing result. The non-destructive testing of the lower end plug of the nuclear fuel assembly provided in the present application does not need human participation at all, and a series of problems caused by manual detection are avoided. BRIEF DESCRIPTION OF DRAWINGS

[0041] The above and other features, advantages, and aspects of the present disclosure will become more apparent with regard to the following detailed description, when taken in conjunction with the accompanying drawings. Throughout the drawings, similar or same reference numerals are used to refer to similar elements throughout the various figures. It should be understood that the drawings are schematic and elements in the drawings are not necessarily to scale.

[0042] Figure 1 A flowchart of a non-destructive testing method of a lower end plug of a nuclear fuel assembly provided by the present application;

[0043] Figure 2 A flowchart of a non-destructive testing method of a lower end plug of a nuclear fuel assembly provided by the present application;

[0044] Figure 3 A structural diagram of a non-destructive testing system of a lower end plug of a nuclear fuel assembly provided by an embodiment of the present application;

[0045] Figure 4 An example diagram of a spring guide pin special tool in a non-destructive testing system of a lower end plug of a nuclear fuel assembly provided by the present application;

[0046] Figure 5 An example diagram of a lower nozzle of a nuclear fuel assembly to be tested provided by the present application;

[0047] Figure 6 An example diagram of a video image of a lower end plug collected by an endoscopic camera probe group in a non-destructive testing system of a lower end plug of a nuclear fuel assembly provided by the present application. DETAILED DESCRIPTION

[0048] The embodiments of the present application are described below with reference to the accompanying drawings. The terms used in the implementation part of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application.

[0049] The embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art can know that the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems as technology develops and new scenarios appear.

[0050] The terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged under appropriate circumstances, and this is only a distinguishing way used in the description of the embodiments of the present application to describe the objects of the same attribute. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, so that the processes, methods, systems, products or equipment containing a series of units do not have to be limited to those units, but can include other units not clearly listed or inherent to these processes, methods, products or equipment.

[0051] Nuclear fuel assembly is a core component of nuclear reactor, and its structural integrity directly affects the safe operation of the reactor and the efficiency of nuclear fuel utilization. Among them, the lower end plug is a key component for connecting the nuclear fuel assembly and the core support structure, and its sealing, crack-free and defect-free are the core guarantee to ensure that the nuclear fuel assembly does not leak coolant and structural failure during long-term service in the core. Therefore, nondestructive testing of the lower end plug is a key link in the manufacturing, transportation and in-service inspection of the nuclear fuel assembly.

[0052] Currently, during the process of taking the new fuel assembly out of the storage tank and transporting it to the reactor installation site, the visual inspection and abnormal identification of the lower end plug mainly rely on manual detection. In actual operation, the operator needs to wear radiation protection equipment and conduct close visual observation or assisted inspection with simple optical tools (such as magnifying glass) in the designated area of the fuel plant to determine whether there are cracks, pores, and incomplete fusion defects on the surface of the ring welding through experience. However, this traditional detection mode has obvious limitations:

[0053] Human factors lead to insufficient detection accuracy: The lower end plug of the nuclear fuel assembly is usually small in size, and the ring welding area of the lower end plug is narrow in space and strong in surface reflectivity. Manual visual detection is easily affected by factors such as visual fatigue, attention fluctuation, and experience difference of the operator, and is prone to miss detection, such as missing small cracks, or misjudgment, such as misjudging normal weld texture as defects, resulting in low repeatability and reliability of the detection results.

[0054] The detection efficiency of manual detection is low, which is difficult to meet the engineering requirements: The ring welding visual inspection and abnormal detection of the lower end plug of the nuclear fuel assembly generally occur when the nuclear fuel assembly is taken out of the new fuel storage tank and during the transportation stage in the fuel plant. Manual detection needs to operate on the lower end plug of each fuel assembly one by one, which takes a long time and cannot match the high efficiency requirement of the transportation link, resulting in prolonged residence time of the nuclear fuel assembly in the plant, increasing the risk of radioactive material diffusion and management cost.

[0055] Therefore, the traditional manual detection mode has been difficult to meet the needs of high precision, high efficiency and high safety for nondestructive testing of the ring welding of the lower end plug of the nuclear fuel assembly.

[0056] In order to solve the above problems, the present application provides a nondestructive testing method and system for the lower end plug of the nuclear fuel assembly.

[0057] Optionally, referring to Figure 1 , the present application provides a flowchart of the nondestructive testing method for the lower end plug of the nuclear fuel assembly.

[0058] It should be noted that the nondestructive testing method of the lower end plug of the nuclear fuel assembly in the embodiment is applied to an intelligent analysis control module in a nondestructive testing system for the lower end plug of the nuclear fuel assembly, and the nondestructive testing system further comprises a six-degree-of-freedom mechanical arm, a spring guide pin special tool mounted on the six-degree-of-freedom mechanical arm, a linear motion module and a pin hole positioning camera mounted on the spring guide pin special tool, and a lower tube seat positioning camera and an endoscopic camera probe group mounted on the linear motion module.

[0059] As shown in Figure 1 The nondestructive testing method of the lower end plug of the nuclear fuel assembly comprises the following steps:

[0060] Step 101, generating first position adjustment information according to first visual media information collected by the lower tube seat positioning camera.

[0061] It should be noted that the visual media information mainly comprises image data and / or video data, and the first visual media information specifically refers to image data and / or video data collected by the lower tube seat positioning camera in the current field of view, and the lower tube seat positioning camera currently includes the lower tube seat of the nuclear fuel assembly to be detected in the field of view; it can be understood that the first visual media information is specifically collected under the condition that the lower tube seat positioning camera includes the lower tube seat of the nuclear fuel to be detected in the field of view; and the first position adjustment information specifically refers to a first position adjustment instruction sent from the intelligent analysis control module to the six-degree-of-freedom mechanical arm, and the generation process of the first position adjustment instruction is as follows:

[0062] Step one, the intelligent analysis control module receives image data and / or video data collected by the lower tube seat positioning camera in the current field of view;

[0063] Step two, the intelligent analysis control module analyzes the image data and / or video data, calculates the first relative position information of the lower tube seat of the nuclear fuel assembly to be detected in the image data and / or video data, and judges whether the calculated relative position information is the same as the preset first target position; the first target position is generally the middle position of the lower tube seat of the nuclear fuel assembly in the current field of view of the lower tube seat positioning camera.

[0064] Step three, when the intelligent analysis control module judges that the calculated first relative position information represents that the nuclear fuel assembly to be detected is not at the first target position, the first position adjustment instruction is calculated based on the first relative position information and the first target position, and the first position adjustment instruction is sent to the six-degree-of-freedom mechanical arm.

[0065] Optionally, the intelligent analysis control module calculates the relative position information of the lower nozzle of the nuclear fuel assembly to be detected in the image data and / or video data collected by the lower nozzle positioning camera, and then determines whether the relative position information represents that the lower nozzle of the nuclear fuel assembly to be detected is at the first target position, i.e., the lower nozzle of the nuclear fuel assembly is at the middle position in the current field of view of the lower nozzle positioning camera. If not, the first position adjustment instruction is calculated based on the relative position information and the first target position.

[0066] It should be noted that the reason for using the six-degree-of-freedom robot arm in the present application is that the six-degree-of-freedom robot arm can move in x, y and z directions and can fully adapt to various three-dimensional space states of the nuclear fuel assembly to be detected in the suspended and stationary state after being grabbed. A robot arm with less than six degrees of freedom cannot be applied to various working scenes, and a robot arm with more than six degrees of freedom is redundant.

[0067] Step 102, controlling the six-degree-of-freedom robot arm to adjust the position according to the first position adjustment information, so as to adjust the lower nozzle positioning camera to the first target pose.

[0068] It should be noted that the first position adjustment information includes a first position adjustment instruction, which is used to adjust the six-degree-of-freedom robot arm to the first target pose, and the first target pose makes the camera optical center of the lower nozzle positioning camera and the nuclear fuel assembly to be detected in the same vertical line.

[0069] Specifically, the process of adjusting the six-degree-of-freedom robot arm to the first target pose is mainly to adjust the height position state of the six-degree-of-freedom robot arm, and adjust the camera optical center of the lower nozzle positioning camera carried by the six-degree-of-freedom robot arm to be in the same vertical line with the nuclear fuel assembly to be detected. That is, the nuclear fuel assembly to be detected is in the center position in the current field of view of the lower nozzle positioning camera.

[0070] Optionally, the intelligent analysis control module sends the first position adjustment instruction to the six-degree-of-freedom robot arm, adjusts the height position of the six-degree-of-freedom robot arm, and adjusts the six-degree-of-freedom robot arm to the first target pose, so that the camera optical center of the lower nozzle positioning camera carried by the six-degree-of-freedom robot arm is in the same vertical line with the nuclear fuel assembly to be detected.

[0071] Step 103, generating second position adjustment information according to the second visual media information collected by the pin hole positioning camera.

[0072] It should be noted that the second visual media information is specifically image data and / or video data collected by the pinhole positioning camera in the current field of view, and the pinhole positioning camera in the current field of view includes the lower end plug of the lower nozzle of the nuclear fuel assembly to be detected; it is not difficult to understand that the second visual media information is collected in the case that the pinhole positioning camera in the current field of view includes the lower end plug of the lower nozzle of the nuclear fuel assembly to be detected; the second position adjustment information is specifically: the second position adjustment instruction sent from the intelligent analysis control module to the six-degree-of-freedom robot, and the generation process of the second position adjustment instruction is as follows:

[0073] Step one, the intelligent analysis control module receives the image data and / or video data collected by the pinhole positioning camera in the current field of view;

[0074] Step two, the intelligent analysis control module analyzes the image data and / or video data, calculates the second relative position information of each pin hole of the lower nozzle of the nuclear fuel assembly to be detected in the image data and / or video data, and judges whether the calculated second relative position information is the same as the preset second target position; the first target position is generally that the whole pin hole of the lower nozzle of the nuclear fuel assembly to be detected is in the middle position of the current field of view of the pinhole positioning camera, and the middle position corresponds to the center point coordinate in the image data and / or video data.

[0075] Taking the lower nozzle of the nuclear fuel assembly to be detected including two pin holes as an example, the intelligent analysis control module inputs the image data and / or video data collected by the pinhole positioning camera in the current field of view into the deep learning network model, obtains the relative positions of the two pin holes in the lower nozzle recognized by the deep learning network model, and records them as and According to the positions of the two pin holes, the coordinate positions of the center points of the two pin holes are calculated, recorded as coordinates The coordinate positions of the center points are the second relative position information of each pin hole of the lower nozzle of the nuclear fuel assembly to be detected in the image data and / or video data mentioned above; then, the center points are subtracted from the center point coordinates of the image data and / or video data to obtain the displacement amount of the six-degree-of-freedom robot in the horizontal direction The displacement amount and the moving direction vector can also be calculated by using the coordinate positions of the two pin holes. The displacement amount and the moving direction vector are included in the second position adjustment instruction. The displacement amount and the moving direction vector can quickly adjust the position and state of the six-degree-of-freedom robot, so that the camera optical center of the lower nozzle positioning camera carried by the six-degree-of-freedom robot is in the same vertical line with the nuclear fuel assembly to be detected.

[0076] Step three, when the intelligent analysis control module judges that the calculated second relative position information represents that the overall pin holes are not in the second target position, a second position adjustment instruction is calculated based on the second relative position information and the second target position, and the second position adjustment instruction is sent to the six-degree-of-freedom robot arm.

[0077] Optionally, the intelligent analysis control module calculates the second relative position information of each pin hole of the lower nozzle of the to-be-detected nuclear fuel assembly in the image data and / or video data collected by the pin hole positioning camera first according to the image data and / or video data collected by the pin hole positioning camera, and then judges whether the second relative position information represents that each pin hole of the lower nozzle of the to-be-detected nuclear fuel assembly is in the second target position, i.e., the overall pin holes of the lower nozzle of the nuclear fuel assembly are in the middle position in the current field of view of the pin hole positioning camera. If not, a second position adjustment instruction is calculated based on the second relative position information and the first target position.

[0078] Step 104, controlling the six-degree-of-freedom robot arm to adjust the position according to the second position adjustment information, so as to adjust the pin hole positioning camera to the second target pose.

[0079] It should be noted that the second position adjustment information includes a second position adjustment instruction, and the second position adjustment instruction is used to adjust the six-degree-of-freedom robot arm to the second target pose, and the second target pose is that the camera optical center of the pin hole positioning camera and the lower end plug of the lower nozzle of the to-be-detected nuclear fuel assembly are in the same vertical line.

[0080] Optionally, the intelligent analysis control module sends the second position adjustment instruction to the six-degree-of-freedom robot arm, adjusts the pose of the six-degree-of-freedom robot arm according to the moving direction and displacement in the second position adjustment instruction, adjusts the six-degree-of-freedom robot arm to the second target pose, and makes the camera optical center of the pin hole positioning camera carried by the six-degree-of-freedom robot arm and the lower end plug of the lower nozzle of the to-be-detected nuclear fuel assembly in the same vertical line.

[0081] It should be noted that the intelligent analysis control module will also call the lower nozzle positioning camera to detect the relative position of the lower nozzle of the to-be-detected nuclear fuel assembly relative to the lower nozzle positioning camera before fixing the lower nozzle of the to-be-detected nuclear fuel assembly.

[0082] Specifically, the intelligent analysis control module receives the fourth visual media information collected by the lower nozzle positioning camera, and the fourth visual media information is specifically the visual media information of the lower nozzle of the to-be-detected nuclear fuel assembly, i.e., the image data and / or video data in the current field of view collected by the lower nozzle positioning camera.

[0083] According to the image data and / or video data collected by the lower nozzle base positioning camera in the current field of view, it is judged whether the lower nozzle base positioning camera is in a preset first target position. When it is judged that the lower nozzle base positioning camera is not in the first target position, fourth position adjustment information is generated, specifically, a fourth position adjustment instruction is generated, and the adjustment instruction is sent to the six-degree-of-freedom robot arm, and the lower nozzle base positioning camera is adjusted to the first target position.

[0084] The principle of adjusting the position of the six-degree-of-freedom robot arm this time is the same as that in step 101 above, and will not be described in detail here.

[0085] Step 105, control the spring guide pin special tool to fix the lower nozzle base of the nuclear fuel assembly to be detected, and control the endoscopic camera probe group to move below the lower end plug, and collect third visual media information.

[0086] The spring guide pin special tool is a special tool designed for non-destructive testing of the lower end plug of the nuclear fuel assembly in this application, which is mainly used to insert the pin into the pin hole of the lower nozzle base of the nuclear fuel assembly, and fix the lower nozzle base of the nuclear fuel assembly to be detected. The third visual media information is the image data and / or video data of the lower end plug of the nuclear fuel assembly to be detected, which is collected by the endoscopic camera probe group.

[0087] Optionally, the intelligent analysis control module controls the pin of the spring guide pin special tool to be inserted into the pin hole of the lower nozzle base, and fixes the nuclear fuel assembly; then, the linear motion module is controlled to transmit the endoscopic camera probe group to the lower side of the lower end plug, and the endoscopic camera probe group collects the image data and / or video data of the lower end plug.

[0088] Specifically, the spring guide pin special tool is mounted on the six-degree-of-freedom robot arm, and the six-degree-of-freedom robot arm includes an end force sensor. The intelligent analysis control module controls the end force sensor to control the contact force of the pin on the spring guide pin special tool, so as to slowly insert the pin into each pin hole of the lower nozzle base of the nuclear fuel assembly to be detected until the contact force reaches the upper limit of the threshold set in the intelligent analysis control module. At the same time, it can also be further judged whether the pin is completely inserted into the pin hole through the field of view of the pin hole positioning camera.

[0089] Step 106, determining the non-destructive testing result of the lower end plug based on the third visual media information.

[0090] The intelligent analysis control module first receives the third visual media information sent by the endoscopic camera probe group. It can be understood that the third visual media information is the image data and / or video data of the lower end plug.

[0091] Optionally, the intelligent analysis control module inputs the image data and / or video data of the lower end plug into the non-destructive testing model based on the deep convolution network to obtain the non-destructive testing result.

[0092] Specifically, the non-destructive testing model based on the deep convolutional network outputs the probability distribution of the normal region and the abnormal region. For the abnormal region, generally includes the welding oxidation color (yellow or blue) in the lower end plug weld region, and the welding defects such as undercut and spatter on the weld surface.

[0093] To sum up, the non-destructive testing method of the lower end plug of the nuclear fuel assembly provided by the application adjusts the position of the lower tube seat positioning camera by using the six-degree-of-freedom mechanical arm and the linear motion module, so that the lower tube seat positioning camera is directly opposite to the lower tube seat of the nuclear fuel assembly to be detected; then, the position of the pin hole positioning camera is adjusted by using the six-degree-of-freedom mechanical arm, so that the pin hole positioning camera is located below the lower end plug, and the spring guide pin special tool is used to fix the nuclear fuel assembly to be detected; finally, the intelligent analysis control module analyzes the third visual media information collected by the endoscopic camera probe group to obtain the non-destructive testing result. The non-destructive testing of the lower end plug of the nuclear fuel assembly provided by the application does not need manual participation throughout the process, and a series of problems caused by manual detection are avoided.

[0094] For example, referring to Figure 2 , the flowchart of the non-destructive testing method of the lower end plug of the nuclear fuel assembly provided by the application is provided.

[0095] Firstly, the intelligent analysis control module starts the lower tube seat positioning camera to collect image data and opens the lower tube seat identification function.

[0096] The intelligent analysis control module determines the pixel position of the lower tube seat through the image data collected by the lower tube seat positioning camera, and then controls the six-degree-of-freedom mechanical arm to move close to the nuclear fuel assembly to be detected in the direction of the nuclear fuel assembly to be detected, while controlling the displacement of the six-degree-of-freedom mechanical arm in the vertical direction to avoid collision with the lower tube seat.

[0097] The intelligent analysis control module starts the pin hole positioning camera to identify the pin holes of the lower tube seat, calculates the position deviation of the center coordinates of each pin hole from the center coordinates of the pin hole positioning camera according to the positions of the pin holes, adjusts the position of the six-degree-of-freedom mechanical arm end base in the horizontal direction based on the position deviation, so as to align the pins with the pin holes, and then controls the six-degree-of-freedom mechanical arm to continue to move in the vertical direction until the pins are completely inserted into the pin holes. In this process, the intelligent analysis control module can judge whether the pins are completely inserted into the pin holes through the threshold value of the contact force fed back by the six-degree-of-freedom mechanical arm or the pin hole positioning camera field of view.

[0098] When the pins are inserted into the pin holes, the six-degree-of-freedom mechanical arm is controlled to constrain the space to limit the nuclear fuel assembly to be detected from moving during hovering, so as to ensure the safety of the lower end plug during detection. The lower tube seat positioning camera is called again to verify whether the lower tube seat is in a normal state. Then, the linear motion module carrying the endoscopic camera probe is controlled to move below the lower end plug to collect video and image information.

[0099] The intelligent analysis control module performs appearance nondestructive detection on the lower end plug image according to the obtained image data, using a nondestructive detection model based on a deep convolution network. According to the probability distribution of the output result, an abnormal area of the lower end plug is identified.

[0100] The above describes a nondestructive detection method for a lower end plug of a nuclear fuel assembly provided by an embodiment of the present application. A system for performing the nondestructive detection method for the lower end plug of the nuclear fuel assembly will be described below.

[0101] Please refer to Figure 3 , Figure 3 FIG. 1 is a structural schematic diagram of a nondestructive detection system for a lower end plug of a nuclear fuel assembly provided by an embodiment of the present application. As shown in FIG. 1, the system includes: Figure 3

[0102] A six-degree-of-freedom mechanical arm, a spring guide pin special tool installed on the six-degree-of-freedom mechanical arm, a linear motion module and a pin hole positioning camera installed on the spring guide pin special tool, a lower tube seat positioning camera and an endoscopic camera probe group installed on the linear motion module, and an intelligent analysis control module for data analysis and issuing control commands.

[0103] According to the functions of the above components, the nondestructive detection system for the lower end plug of the nuclear fuel assembly can be divided into four modules: a conveying module, a positioning module, a nondestructive detection module, and an intelligent analysis control module.

[0104] The conveying module mainly includes the six-degree-of-freedom mechanical arm and the linear motion module; the positioning module includes the lower tube seat positioning camera, the pin hole positioning camera, and the spring guide pin special tool; the nondestructive detection module includes the endoscopic camera probe group; and the intelligent analysis control module realizes analysis of the state, visual media information, and other data of the above three modules and issues control commands for control.

[0105] Next, the connection of each component, the main functions, and the full process of nondestructive detection of the lower end plug of the nuclear fuel assembly will be introduced one by one.

[0106] The six-degree-of-freedom mechanical arm adopts a compact structure design and is installed on a mounting base. It can adjust the movement of the lower tube seat positioning camera and the pin hole positioning camera carried by it in the x, y, and z directions, and assist the spring guide pin special tool in inserting the pins into the pin holes in the lower tube seat of the nuclear fuel assembly to be detected. In general, the six-degree-of-freedom mechanical arm can fully adapt to various three-dimensional space states of the nuclear fuel assembly to be detected after being gripped, can avoid collision of the components in the nondestructive detection system with the lower end plug, and ensures the safety and reliability of the nuclear fuel assembly. Specifically, the working accuracy of the six-degree-of-freedom mechanical arm can be ±0.1 mm, and the working space range is 956 mm.

[0107] ​The lower nozzle positioning camera is installed on the linear motion module, and is mainly used for collecting first visual medium information, which is image data and / or video data collected under the current field of view of the lower nozzle positioning camera and including the situation of the lower nozzle of the nuclear fuel assembly to be detected.

[0108] The pin hole positioning camera is installed at the center of the fixed plate of the spring guide pin special tool, and is mainly used for collecting second visual medium information, which is image data and / or video data collected under the current field of view of the pin hole positioning camera and including the situation of the lower end plug of the lower nozzle of the nuclear fuel assembly to be detected. Specifically, after the six-degree-of-freedom robot arm is moved to the preset working area, the intelligent analysis control module searches the pin holes of the lower nozzle of the nuclear fuel assembly to be detected by using the pin hole positioning camera, and collects image data and / or video data including the pin holes of the lower nozzle of the nuclear fuel assembly to be detected by using the pin hole positioning camera.

[0109] The spring guide pin special tool is installed at the end of the six-degree-of-freedom robot arm, and the spring guide pin special tool is mainly used for fixing the lower nozzle of the nuclear fuel assembly by inserting the pins of the spring guide pin special tool into the pin holes of the lower nozzle of the nuclear fuel assembly to be detected. The pin hole positioning camera is installed at the center of the front end of the spring guide pin special tool, and the linear motion module is installed at the rear end of the spring guide pin special tool. The spring guide pin special tool includes at least two groups of pins distributed in a diagonal line; the intelligent analysis control module controls the six-degree-of-freedom robot arm moved to the preset working area to move upward in the vertical direction until the pins of the spring guide pin special tool are completely inserted into the pin holes.

[0110] Specifically, the intelligent analysis control module controls the contact force of the pins on the spring guide pin special tool by controlling the end force sensor on the six-degree-of-freedom robot arm, so as to slowly insert the pins into the pin holes of the lower nozzle of the nuclear fuel assembly to be detected until the contact force reaches the upper threshold set in the intelligent analysis control module; the other condition for stopping the movement of the six-degree-of-freedom robot arm is that the screen in the pin hole positioning camera is completely blocked by the lower nozzle. In this process, since the lower nozzle of the nuclear fuel assembly has only 2 pin holes, and the pin holes of the nuclear fuel assembly are mirror arranged, 2 spring guide pins are retracted into the special tool during the operation of any nuclear fuel assembly.

[0111] For example, referring to Figure 4 , the example diagram of the spring guide pin special tool in the non-destructive testing system of the lower end plug of the nuclear fuel assembly provided by the present application is provided; referring to Figure 5 , the example diagram of the lower nozzle of the nuclear fuel assembly to be detected provided by the present application is provided.

[0112] Figure 4 1 is a pin in the spring guide pin special tool, Figure 5The middle 2 is a pin hole of the lower nozzle. Specifically, the pin 1 is inserted into the pin hole 2 to fix the lower nozzle of the nuclear fuel assembly to be detected.

[0113] It is not difficult to understand that the spring guide pin special tool is used to fix the lower nozzle of the nuclear fuel assembly to be detected, which can ensure that the nuclear fuel assembly to be detected will not shake and will not displace during the non-destructive testing of the lower end plug.

[0114] In addition, before the spring guide pin special tool is used to fix the nuclear fuel assembly to be detected, the intelligent analysis control module will call the lower nozzle positioning camera again to collect image data and / or video data under its current field of view, and determine whether the lower nozzle and the lower end plug of the nuclear fuel assembly to be detected are in the preset target position by analyzing the image data and / or video data under the current field of view. After determining that the position of the lower end plug in the lower nozzle is correct, the linear motion module is started.

[0115] The linear motion module is fixed at the rear end of the spring guide pin special tool, the lower nozzle positioning camera and the endoscopic camera probe group are installed on the linear motion module, and the linear motion module can carry the endoscopic camera probe group and the lower nozzle positioning camera to perform telescopic motion. Moreover, the relative positions of the linear motion module, the lower nozzle positioning camera, the endoscopic camera probe group and the spring guide pin special tool in the numerical direction are fixed.

[0116] The linear motion module includes a moving slider, and the endoscopic camera probe group is installed on the moving slider. The intelligent analysis module controls the one-dimensional motion of the endoscopic camera probe group by controlling the movement of the moving slider, and moves the endoscopic camera probe group below the lower end plug.

[0117] The endoscopic camera probe group includes multiple groups of endoscopic cameras, which are arranged in a horizontal fixed interval to effectively protect the safety of the guide tube. The guide tube is a part of the nuclear fuel assembly to be detected, which penetrates through the entire nuclear fuel assembly to support and fix the entire nuclear fuel assembly. During the entire non-destructive testing process, the guide tube can ensure the safety of all parts in the nuclear fuel assembly. The main function of the endoscopic camera probe group is to collect image data and / or video data of the lower end plug.

[0118] For example, referring to Figure 6 The video image of the lower end plug collected by the endoscopic camera probe group in the non-destructive testing system of the lower end plug of the nuclear fuel assembly provided by the application is shown in the example.

[0119] In addition, the non-destructive testing system of the lower end plug of the nuclear fuel assembly further includes an information exchange module, which is mainly used for information interaction between the endoscopic camera probe group and the intelligent analysis control module. Specifically, after the endoscopic camera probe group collects the image data and / or video data of the lower end plug, it sends the data to the intelligent analysis control module through the information exchange module.

[0120] The intelligent analysis module is configured to generate first position adjustment information according to the first visual media information, to control the six-degree-of-freedom robot arm to adjust the position according to the first position adjustment information, so that the lower nozzle positioning camera is adjusted to a first target pose, and the first target pose is that the camera optical center of the lower nozzle positioning camera and the lower nozzle of the nuclear fuel assembly to be detected are on the same vertical line; generate second position adjustment information according to the second visual media information collected by the pin hole positioning camera, to control the six-degree-of-freedom robot arm to adjust the position according to the second position adjustment information, so that the pin hole positioning camera is adjusted to a second target pose; and the second target pose is that the camera optical center of the pin hole positioning camera and the lower end plug are on the same vertical line; then control the spring guide pin special tool to fix the lower nozzle of the nuclear fuel assembly to be detected, and control the endoscopic camera probe group to move below the lower end plug, collect third visual media information, and determine the non-destructive testing result of the lower end plug based on the third visual media information. For the intelligent analysis control module, details are not described here, and the non-destructive testing method of the lower end plug of the nuclear fuel assembly is described above.

[0121] In summary, the non-destructive testing system of the lower end plug of the nuclear fuel assembly provided by the application can realize unattended full-automatic operation, each positioning camera completes collection and analysis of visual media information, and the position of each camera is adjusted based on the information analysis result, then the nuclear fuel assembly to be detected is fixed, and finally the endoscopic camera probe group is used to collect visual media information of the lower end plug, and the intelligent analysis control module performs non-destructive testing based on the visual media information of the lower end plug.

[0122] In addition, it should be noted that the apparatus embodiments described above are only schematic, and the units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, i.e., can be located in one place, or can be distributed on multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment. In addition, in the apparatus embodiments provided by the application, the connection relationship between the modules indicates that there is a communication connection between them, which can be implemented as one or more communication buses or signal lines.

[0123] Those skilled in the art can clearly understand that the application can be implemented by means of software plus necessary universal hardware, and of course can also be implemented by means of dedicated hardware including special integrated circuit, special CPU, special memory, special component, etc. Generally, any function completed by computer program can be easily implemented by corresponding hardware, and the specific hardware structure for implementing the same function can also be various, such as analog circuit, digital circuit or special circuit, etc. However, for the application, software program implementation is a better embodiment. Based on such understanding, the technical solution of the application or the part of the application which makes contribution to the prior art can be embodied in the form of software product, which is stored in readable storage medium, such as computer floppy disk, U disk, mobile hard disk, ROM, RAM, magnetic disk or optical disk, etc., and includes a plurality of instructions for making a computer device (which can be personal computer, training device or network device, etc.) execute the method described in various embodiments of the application.

[0124] In the above embodiments, the implementation can be achieved by software, hardware, firmware or any combination thereof, entirely or partially. When implemented by software, the implementation can be achieved in the form of a computer program product, entirely or partially.

[0125] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the flow or function described in the embodiments of the application is generated entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another, for example, the computer instructions can be transmitted from one website, computer, training device or data center to another website, computer, training device or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that can be stored by a computer or a data storage device such as a training device, a data center, etc. integrated with one or more available media sets. The available medium can be a magnetic medium (such as a floppy disk, a hard disk, a magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid state disk (SSD)), etc.

Claims

1. A method of non-destructive testing of a lower end plug of a nuclear fuel assembly, characterized by, The application discloses an intelligent analysis control module applied to a nondestructive testing system of a lower end plug of a nuclear fuel assembly. The method comprises: generating first position adjustment information according to first visual medium information collected by the lower tube seat positioning camera; the first visual medium information is collected when it is detected that the lower tube seat positioning camera currently includes the lower tube seat of the nuclear fuel assembly to be detected in a field of view; controlling the six-degree-of-freedom robot arm to adjust a position according to the first position adjustment information, so that the lower tube seat positioning camera is adjusted to a first target pose; the first target pose is that a camera optical center of the lower tube seat positioning camera is on the same plumb line as the lower tube seat of the nuclear fuel assembly to be detected; generating second position adjustment information according to second visual medium information collected by the pin hole positioning camera; the second visual medium information is collected when it is detected that the pin hole positioning camera currently includes the lower end plug of the lower tube seat of the nuclear fuel assembly to be detected in a field of view; controlling the six-degree-of-freedom robot arm to adjust a position according to the second position adjustment information, so that the pin hole positioning camera is adjusted to a second target pose; the second target pose is that a camera optical center of the pin hole positioning camera is on the same plumb line as the lower end plug; controlling the spring guide pin special tool to fix the lower tube seat of the nuclear fuel assembly to be detected, and controlling the endoscopic camera probe group to move below the lower end plug to collect third visual medium information; determining a nondestructive testing result of the lower end plug based on the third visual medium information.

2. The non-destructive testing method of a lower end plug of a nuclear fuel assembly according to claim 1, characterized by, The first position adjustment information comprises a first position adjustment instruction, and the first position adjustment information is generated according to the first visual medium information collected by the lower tube seat positioning camera, which comprises: analyzing the first visual medium information to obtain a first analysis result; determining first relative position information of the lower tube seat of the nuclear fuel assembly to be detected based on the first analysis result; when the first relative position information indicates that the lower tube seat of the nuclear fuel assembly to be detected is not at a preset first target position, generating the first position adjustment instruction and sending the first position adjustment instruction to the six-degree-of-freedom robot arm.

3. The method of non-destructive examination of a lower end plug of a nuclear fuel assembly according to claim 1, characterized in that, The second position adjustment information comprises a second position adjustment instruction, and the second position adjustment information is generated according to the second visual medium information collected by the pin hole positioning camera, which comprises: analyzing the second visual medium information to obtain a second analysis result; determining second relative position information of each pin hole in the lower tube seat based on the second analysis result; when the second relative position information indicates that each pin hole is not at a preset second target position, generating the second position adjustment instruction and sending the second position adjustment instruction to the six-degree-of-freedom robot arm.

4. The method of non-destructive examination of a lower end plug of a nuclear fuel assembly according to claim 1, characterized in that, Before determining the non-destructive testing result of the lower end plug based on the third visual media information after controlling the spring guide pin special tool to fix the lower nozzle of the nuclear fuel assembly to be detected and controlling the endoscope camera probe group to move below the lower end plug to collect the third visual media information, the method further comprises: Receiving the third visual media information sent by the endoscope camera probe group; the third visual media information is the visual media information of the lower end plug collected by the endoscope camera probe group.

5. The method for non-destructive examination of a lower end plug of a nuclear fuel assembly according to claim 1, characterized in that, The method further comprises: Inputting the third visual media information into a non-destructive testing model based on a deep convolutional network to obtain the non-destructive testing result.

6. The method for non-destructive examination of a lower end plug of a nuclear fuel assembly according to claim 1, characterized in that, Before determining the non-destructive testing result of the lower end plug based on the third visual media information after controlling the six-degree-of-freedom robot arm to adjust the position according to the second position adjustment information to make the pin hole positioning camera adjust to the second target pose, the method further comprises: Receiving fourth visual media information collected by the lower nozzle positioning camera; the fourth visual media information is the visual media information of the lower nozzle of the nuclear fuel assembly to be detected; When the fourth visual media information indicates that the lower nozzle positioning camera is not at the preset first target position, generating fourth position adjustment information according to the fourth visual media information to control the six-degree-of-freedom robot arm to adjust the lower nozzle positioning camera to the first target pose according to the fourth position adjustment information.

7. A non-destructive testing system for a lower end plug of a nuclear fuel assembly, the system comprising: The method comprises: A six-degree-of-freedom robot arm; A spring guide pin special tool mounted on the six-degree-of-freedom robot arm; A linear motion module and a pin hole positioning camera mounted on the spring guide pin special tool; the pin hole positioning camera is used to collect second visual media information; the second visual media information is collected when it is detected that the pin hole positioning camera currently includes the lower end plug of the lower nozzle of the nuclear fuel assembly to be detected in the field of view; A lower nozzle positioning camera and an endoscope camera probe group mounted on the linear motion module; the lower nozzle positioning camera is used to collect first visual media information; The first visual media information is collected when it is detected that the lower nozzle positioning camera currently includes the lower nozzle of the nuclear fuel assembly to be detected in the field of view; The system further comprises an intelligent analysis control module, configured to generate first position adjustment information based on the first visual media information, to control the six-degree-of-freedom robot arm to adjust the position according to the first position adjustment information, so that the lower nozzle positioning camera is adjusted to a first target pose, and the first target pose is that the camera optical center of the lower nozzle positioning camera is on the same vertical line as the lower nozzle of the nuclear fuel assembly to be detected; generate second position adjustment information based on the second visual media information collected by the pin hole positioning camera, to control the six-degree-of-freedom robot arm to adjust the position according to the second position adjustment information, so that the pin hole positioning camera is adjusted to a second target pose, and the second target pose is that the camera optical center of the pin hole positioning camera is on the same vertical line as the lower end plug; then control the spring guide pin special tool to fix the lower nozzle of the nuclear fuel assembly to be detected, and control the endoscopic camera probe group to move below the lower end plug, collect third visual media information, and determine the non-destructive testing result of the lower end plug based on the third visual media information.

8. The non-destructive testing system of a lower end plug of a nuclear fuel assembly according to claim 7, characterized in that, The spring guide pin special tool comprises at least two groups of pins arranged in a diagonal line; The intelligent analysis control module inserts the at least two groups of pins into the pin holes of the lower nozzle of the nuclear fuel assembly to be detected by controlling the contact force on the six-degree-of-freedom robot arm.

9. The non-destructive testing system of a lower end plug of a nuclear fuel assembly according to claim 7, characterized in that, The linear motion module comprises a moving slider, and the endoscopic camera probe group is installed on the moving slider; The intelligent analysis control module controls the moving slider to move the endoscopic camera probe group below the lower end plug.

10. The non-destructive testing system of a lower end plug of a nuclear fuel assembly according to claim 7, characterized in that, The non-destructive testing system of the lower end plug of the nuclear fuel assembly further comprises an information exchange module; The information exchange module is configured to send the third visual media information collected by the endoscopic camera probe group to the intelligent analysis control module.

Images