Nuclear island containment outer wall defect detection method

Abstract

The invention provides a nuclear island containment outer wall defect detection method. The method comprises the following steps: building a special unmanned aerial vehicle applied to nuclear island containment outer wall detection; collecting a three-dimensional coarse model of the outer wall of the nuclear island containment through a special unmanned aerial vehicle; setting flight parameters of the special unmanned aerial vehicle and generating a route; performing video detection on the outer wall of the nuclear island containment through a special unmanned aerial vehicle; video data fusion is carried out by combining the route, and detection data is analyzed. The method is applied to nuclear island containment outer wall defect inspection, safe and efficient containment detection is achieved, quantitative and qualitative analysis is conducted on the defect state, the problem of nuclear power station containment outer wall appearance inspection engineering implementation is solved, and safety assessment feasibility is provided for a third barrier of a nuclear power station.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear island containment outer wall defect detection, and in particular to a nuclear island containment outer wall defect detection method. Background Art

[0002] Most of the nuclear power plants built in China are located in coastal areas. Under normal circumstances, they are subject to erosion from sea breezes with high chloride ion content and direct sunlight, as well as environmental factors such as typhoons and earthquakes. These environmental factors lead to aging damage to the containment of nuclear power plants. The most common concrete aging damage to the containment structure includes: concrete cracks; concrete material peeling; concrete holes. Therefore, it is very necessary to conduct regular appearance inspections of the containment of nuclear power plants, conduct basic assessments of its appearance defects, and continuously track and analyze them.

[0003] The traditional inspection method for the outer wall of the nuclear island containment is to conduct routine manual monitoring of its outer cylinder, but it has disadvantages such as the containment being too high, no handholds, inconvenient manual climbing, and large visual errors. At the same time, the inspection efficiency is low and there are great safety hazards in the implementation of the project.

[0004] The detection of defects on the outer wall of the nuclear island containment in the nuclear power field is still in the exploratory stage. Whether in terms of detection means or detection technology, research is still needed to improve the level of detection means, and the detection technology needs to be strengthened. Summary of the invention

[0005] The purpose of the present invention is to provide a method for detecting defects in the outer wall of a nuclear island containment vessel, solve the problem of implementing the appearance inspection project of the outer wall of the containment vessel of a nuclear power plant, and provide feasibility of safety assessment for the third barrier of a nuclear power plant.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for detecting defects on the outer wall of a nuclear island containment vessel comprises the following steps:

[0008] Step 1: Build a special drone for nuclear island containment outer wall inspection;

[0009] Step 2: Use a dedicated drone to collect a 3D rough model of the outer wall of the nuclear island containment vessel;

[0010] Step 3: Set the flight parameters of the dedicated drone and generate the route;

[0011] Step 4: Use a dedicated drone to conduct video inspection of the outer wall of the nuclear island containment;

[0012] Step 5: Combine the video data with the flight path and analyze the detection data.

[0013] Step 1 specifically includes:

[0014] Step 1.1: Perform 3D modeling based on the size requirements of the drone and select the required carbon fiber rods, fixed windows and grid support points;

[0015] Step 1.2: Assemble the carbon fiber rods and the fixed windows and the grid fulcrums to form a carbon fiber spherical node grid. After assembling them into one, install the light strip on the fixed window and the drone fixing frame. The overall structure of the drone with anti-collision and anti-fall function based on the elastic structure is installed, and the carried equipment is installed on the drone fixing frame 5. The dedicated drone platform for nuclear island containment outer wall inspection is completed.

[0016] Furthermore, the onboard device is a video camera, an infrared camera or a laser radar.

[0017] Step 2 specifically includes:

[0018] Step 2.1: Mount the laser radar on a dedicated drone platform to collect laser point cloud data of the nuclear island containment;

[0019] Step 2.2: Use the point cloud reconstruction algorithm to stitch the laser point cloud data, generate the visualized nuclear island containment laser point cloud data, and establish a rough model;

[0020] Step 2.3: Convert the laser point cloud data into a data format recognizable by the collaborative control platform.

[0021] Furthermore, the data format in step 2.3 is .OBG data format.

[0022] Step 3 specifically includes:

[0023] Step 3.1: Read the nuclear island containment .OBG data through the UAV collaborative control platform;

[0024] Step 3.2: For the three-dimensional model of the nuclear island containment, select the containment detection range that needs to be detected, automatically identify and extract the buildings of the point cloud model in the 3D virtual scene, and obtain the point cloud projection image;

[0025] Step 3.3: Perform image corrosion and dilation processing based on the projection image to filter out reflections and model defect areas;

[0026] Step 3.4: According to the detection distance required for the nuclear island containment flight inspection, combined with the camera focal length, set the trajectory generation parameters, obtain the shape of the visual inspection three-dimensional envelope surface, generate the inspection envelope surface projection map, and perform three-dimensional full coverage of the visual route based on the inspection envelope surface;

[0027] Step 3.5: Detect the coverage rate according to the requirements of the flight inspection of the nuclear island containment, set the flight parameters in combination with the field of view angle of the camera, and generate different flight routes for multiple drones to operate simultaneously within the inspection envelope range;

[0028] Step 3.6: Download multiple flight routes to different drones simultaneously, and perform collaborative operations for the inspection of the nuclear island containment at the same time.

[0029] Furthermore, the flight parameters in Step 3.5 include flight altitude, flight width, and route length.

[0030] In Step 3.5, the flight routes for multiple drones to operate simultaneously are "Ji"-shaped distribution routes.

[0031] Step 4 specifically includes:

[0032] Step 4.1: Mount the camera on a dedicated drone platform, and use the collaborative control platform to operate multiple drones to take off with one key to perform collaborative operations for video collection of the nuclear island containment;

[0033] Step 4.2: The drone transmits the video data to the collaborative control platform in real time through the video transmission module to implement online detection of the outer wall of the containment; if a certain drone detects a suspected display, the collaborative control platform performs fixed-point hovering of the corresponding drone to capture a high-resolution image of the display, and judges the authenticity and nature of the display;

[0034] Step 4.3: During the video collection of the drone for the containment, both the drone side and the collaborative control platform side store the video data.

[0035] Step 5 specifically includes:

[0036] Step 5.1: Integrate the data collected by the camera, the flight trajectory parameters of the aircraft, and the three-dimensional model of the nuclear island on the collaborative control platform to generate video detection data for the nuclear island containment;

[0037] Step 5.2: Mark the display area of the nuclear island containment on the three-dimensional model, extract frame pictures of the corresponding defective videos, establish a link between the mark and the defective pictures, and realize defect detection positioning and characterization;

[0038] Step 5.3: During the video collection of the drone for the containment, the size of the defect can be measured according to the camera model, and the position parameters and size of the defect are attached below the defective picture for explanation to realize quantitative analysis of the defect.

[0039] Compared with the prior art, the method for detecting defects on the outer wall of the nuclear island containment provided by the present invention has the following beneficial effects:

[0040] The present invention is applied to the defect inspection of the outer wall of the nuclear island containment, realizes safe and efficient detection of the containment, and performs quantitative and qualitative analysis of the defect status, solves the implementation problem of the appearance inspection project of the outer wall of the containment of the nuclear power plant, and provides the feasibility of safety assessment for the third barrier of the nuclear power plant.

[0041] The present invention uses an outer wall inspection drone to carry out inspections, which can significantly save costs and implement special inspections, while also saving a large amount of indirect costs by reducing on-site damage.

[0042] Furthermore, the special drone platform developed by the present invention has a drone anti-collision and anti-fall structural protective device with an elastic structure, and a drone fixing mechanism is provided in the protective device. The fixed drone structure can achieve 360-degree flipping and 360-degree circumferential rotation. When the drone collides, it can use inertia to continue to maintain the flight posture and continue to fly. The protective cage has a fixable window that does not affect the field of view of the mounted equipment. The window can also be arranged with a light strip to provide ambient lighting for the inspection area to meet the illumination required for camera inspection and reduce the risk of falling. Under the protection of the protective device, the drone platform has the ability to withstand a 50-meter fall without damage in the event of an explosion, and the ability to withstand a fall without damaging the containment structure of the nuclear power plant, thereby achieving the purpose of true non-destructive testing.

[0043] Furthermore, when conducting inspections, drones can set regular trajectories, and drones can fly inspections along simple trajectories, which is less risky and more efficient. Each drone's inspection track is planned in a "J"-shaped polyline to perform scanning. When encountering obstacles, the track automatically avoids the obstacles.

[0044] Furthermore, the UAV collaborative operation control platform can realize the coordinated formation of multiple UAVs, carrying cameras and photoelectric detection equipment to detect the status of nuclear power containment concrete. The detection distance, flight speed, and detection coverage area of ​​the UAV can all be set according to the inspection requirements when generating the route, ensuring the integrity of the video inspection while realizing multiple UAV inspections, greatly improving the inspection efficiency and achieving the purpose of safe and efficient inspection.

[0045] Furthermore, after the drone completes video data acquisition, the three-dimensional scene information, geographic space information and drone route information are integrated together for rendering and display. The video clip data can be integrated into the 3D virtual scene. At the same time, cracks, breakages and other problems are detected, located and recorded in the 3D virtual scene. The defect size is calculated based on the drone's flight parameters and the camera's internal parameters to achieve data quantitative, positioning and qualitative analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for the technical description.

[0047] Figure 1 A schematic diagram of the anti-collision and anti-fall structure of a UAV based on an elastic structure provided by the present invention;

[0048] Figure 2 A schematic diagram of a UAV anti-collision and anti-fall structure based on an elastic structure provided by the present invention, wherein a UAV fixing frame is shown;

[0049] Figure 3 A schematic diagram for generating a three-dimensional model provided by the present invention;

[0050] Figure 4 A schematic diagram of collaborative flight route planning provided by the present invention;

[0051] Figure 5 A schematic diagram of the video fusion process provided by the present invention.

[0052] Description of reference numerals:

[0053] 1. Carbon fiber rod; 2. Fixable window; 3. Grid node; 4. Light strip; 5. Drone fixing frame; 6. Containment detection range; 7. Containment building; 8. Check envelope surface; 9. Envelope surface projection; 10. Check three-dimensional envelope surface; 11. Containment point cloud projection; 12. Drone trajectory route one; 13. Drone trajectory route two; 14. Drone trajectory route three. DETAILED DESCRIPTION

[0054] The following is further explained in detail through specific implementation methods.

[0055] Aiming at the special environment of the nuclear island containment and the safety requirements of the nuclear power plant, the present invention develops a special UAV platform for the inspection of the nuclear power plant containment; a special UAV platform is used to carry a laser module to scan the nuclear island containment, collect laser point cloud data of the nuclear island containment, establish a three-dimensional rough model of the nuclear island containment, and generate .OBG format data; a special control platform for multi-machine collaborative inspection is developed to process the collected rough model three-dimensional model .OBG format data, select the area to be inspected, input video detection conditions, and the algorithm automatically generates multiple routes; the routes are downloaded to the developed UAV, and a camera is carried out for online video inspection. If a suspected display is found, the UAV hovers at a fixed point to capture a high-resolution image of the display, and a more detailed observation is performed to determine the authenticity and nature of the display; the data collected by the UAV is integrated with the three-dimensional model and the route to construct a defect map. Figure 3 3D model is used to study the distribution of defects such as concrete cracks, concrete material peeling, and concrete holes, and the defect data is calculated to achieve quantitative and qualitative analysis.

[0056] like Figures 1 to 5 As shown, a method for detecting defects on the outer wall of a nuclear island containment vessel proposed by the present invention comprises the following steps:

[0057] Step 1: Build a special drone for nuclear island containment outer wall inspection;

[0058] Step 2: Use a dedicated drone to collect a 3D rough model of the outer wall of the nuclear island containment vessel;

[0059] Step 3: Set the flight parameters of the dedicated drone and generate the route;

[0060] Step 4: Use a dedicated drone to conduct video inspection of the outer wall of the nuclear island containment;

[0061] Step 5: Combine the video data with the flight path and analyze the detection data.

[0062] Step 1 specifically includes the following:

[0063] Step 1.1: Figure 1 As shown, firstly, according to the size requirements of the UAV, three-dimensional modeling is performed to select the required carbon fiber rods 1, the fixed windows 2 and the grid support points 3;

[0064] Step 1.2: Assemble the carbon fiber rod 1 and the fixed window 2 with the grid support 3 to form a carbon fiber spherical node grid. After assembling them into one, install the light strip 4 on the fixed window 2 and install the drone fixing frame 5 (such as Figure 2 As shown in the figure, the overall structure of the UAV anti-collision and anti-fall based on the elastic structure is installed. The carried equipment (such as a video camera, an infrared camera or a laser radar) is installed on the UAV fixing frame 5, and the dedicated UAV platform for nuclear island containment outer wall detection is built.

[0065] Step 2 specifically includes the following:

[0066] Step 2.1: Mount the laser radar on the dedicated drone in step 1 to collect laser point cloud data of the nuclear island containment;

[0067] Step 2.2: Use the point cloud reconstruction algorithm to stitch the laser point cloud data, generate the visualized nuclear island containment laser point cloud data, and establish a rough model;

[0068] Step 2.3: Convert the laser point cloud data into the .OBG data format recognizable by the collaborative control platform.

[0069] like Figure 3 and Figure 4 As shown, step 3 specifically includes the following contents:

[0070] Step 3.1: First, use the UAV collaborative control software (used for UAV containment inspection route planning and UAV collaborative control) to read the nuclear island containment .OBG data;

[0071] Step 3.2: For the three-dimensional model of the nuclear island containment, firstly, the containment detection range 6 to be detected is selected, and the building 7 of the point cloud model in the 3D virtual scene is automatically identified and extracted to obtain a point cloud projection image 11;

[0072] Step 3.3: Perform image corrosion and expansion processing based on the projection image to filter out some reflections such as windows and modeling defect areas;

[0073] Step 3.4: According to the detection distance required for the nuclear island containment flight inspection, combined with the camera focal length, set the generation trajectory parameters, obtain the shape of the visual inspection three-dimensional envelope surface 10, and finally generate the inspection envelope surface projection diagram 9. According to the inspection envelope surface 8, perform three-dimensional full coverage of the visual route;

[0074] Step 3.5: According to the detection coverage of the nuclear island containment flight inspection requirements, combined with the camera field of view, set the flight parameters such as the aircraft flight altitude, flight width, and route length, and generate different routes in the shape of a "J" for multiple drones to operate simultaneously within the inspection envelope (drone trajectory route 1 12, drone trajectory route 2 13, drone trajectory route 3 14);

[0075] Step 3.6: Multiple routes can be simultaneously downloaded to different drones to carry out collaborative inspection of the nuclear island containment.

[0076] When conducting inspections, drones can set regular trajectories. Drones can fly inspections along simple trajectories, which is less risky and more efficient. Each drone's inspection track is planned in a "J"-shaped polyline to perform scanning. When encountering obstacles, the track automatically avoids the obstacles.

[0077] Step 4 specifically includes the following:

[0078] Step 4.1: Mount the camera on a dedicated drone platform, and use the collaborative control platform to control multiple drones to take off with one click to perform collaborative operations for nuclear island containment video collection;

[0079] Step 4.2: The drone transmits video data to the collaborative control platform in real time through the image transmission module to implement online detection of the outer wall of the containment. If a drone is found to have a suspected display, the collaborative control platform can hover the corresponding drone at a fixed point, capture the high-resolution image of the display, and judge the authenticity and nature of the display;

[0080] Step 4.3: During the UAV containment video acquisition process, both the UAV end and the collaborative control platform end can store the video data.

[0081] like Figure 5 As shown, step 5 specifically includes the following contents:

[0082] Step 5.1: The data collected by the camera, the flight trajectory parameters of the aircraft, and the three-dimensional model of the nuclear island are integrated on the collaborative control platform to generate the nuclear island containment video detection data;

[0083] Step 5.2: Mark the nuclear island containment display area on the 3D model, extract the frame image of the corresponding defect video, establish a link between the mark and the defect image, and realize the detection, positioning and qualitative analysis of cracks, breakages and other defects;

[0084] Step 5.3: During the drone containment video acquisition process, the flight trajectory and focal length of the drone can be determined. The size of the defect can be measured based on the camera model, and the location parameters and defect size of the defect are attached below the defect image for description, thereby achieving quantitative analysis of the defect.

[0085] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for detecting defects in the outer wall of a nuclear island containment vessel, characterized in that: The following steps are involved: Step 1: Build a special drone for nuclear island containment outer wall inspection; Step 2: Use a dedicated drone to collect a 3D rough model of the outer wall of the nuclear island containment vessel; Step 3: Set the flight parameters of the dedicated drone and generate the route; Step 4: Use a dedicated drone to conduct video inspection of the outer wall of the nuclear island containment; Step 5: Combine the video data with the flight path and analyze the detection data.

2. The method for detecting defects in the outer wall of a nuclear island containment vessel according to claim 1, characterized in that: Step 1 specifically includes: Step 1.1: Perform 3D modeling based on the size requirements of the drone and select the required carbon fiber rods, fixed windows and grid support points; Step 1.2: Assemble the carbon fiber rods and the fixed windows and the grid fulcrums to form a carbon fiber spherical node grid. After assembling them into one, install the light strip on the fixed window and the drone fixing frame. The overall structure of the drone with anti-collision and anti-fall function based on the elastic structure is installed, and the carried equipment is installed on the drone fixing frame 5. The dedicated drone platform for nuclear island containment outer wall inspection is completed.

3. The method for detecting defects in the outer wall of a nuclear island containment vessel according to claim 2, characterized in that: The equipment carried is a video camera, infrared camera or lidar.

4. The method for detecting defects in the outer wall of a nuclear island containment vessel according to claim 1, characterized in that: Step 2 specifically includes: Step 2.1: Mount the laser radar on a dedicated drone platform to collect laser point cloud data of the nuclear island containment; Step 2.2: Use the point cloud reconstruction algorithm to stitch the laser point cloud data, generate the visualized nuclear island containment laser point cloud data, and establish a rough model; Step 2.3: Convert the laser point cloud data into a data format recognizable by the collaborative control platform.

5. The method for detecting defects in the outer wall of a nuclear island containment vessel according to claim 4, characterized in that: The data format in step 2.3 is .OBG data format.

6. The method for detecting defects in the outer wall of a nuclear island containment vessel according to claim 1, characterized in that: Step 3 specifically includes: Step 3.1: Read the nuclear island containment .OBG data through the UAV collaborative control platform; Step 3.2: For the three-dimensional model of the nuclear island containment, select the containment detection range that needs to be detected, automatically identify and extract the buildings of the point cloud model in the 3D virtual scene, and obtain the point cloud projection image; Step 3.3: Perform image corrosion and dilation processing based on the projection image to filter out reflections and model defect areas; Step 3.4: According to the detection distance required for the nuclear island containment flight inspection, combined with the camera focal length, set the trajectory generation parameters, obtain the shape of the visual inspection three-dimensional envelope surface, generate the inspection envelope surface projection map, and perform three-dimensional full coverage of the visual route based on the inspection envelope surface; Step 3.5: According to the inspection coverage requirements of the nuclear island containment flight inspection, the flight parameters are set in combination with the camera field of view, and different routes for multiple drones to operate simultaneously are generated within the inspection envelope; Step 3.6: Download multiple routes to different drones at the same time, and conduct collaborative inspection of the nuclear island containment.

7. The method for detecting defects in the outer wall of a nuclear island containment vessel according to claim 6, characterized in that: The flight parameters in step 3.5 include flight altitude, flight width, and route length.

8. The method for detecting defects in the outer wall of a nuclear island containment vessel according to claim 6, characterized in that: In step 3.5, the routes of multiple drones operating simultaneously are distributed in the shape of a "J".

9. The method for detecting defects in the outer wall of a nuclear island containment vessel according to claim 1, characterized in that: Step 4 specifically includes: Step 4.1: Mount the camera on a dedicated drone platform, and use the collaborative control platform to control multiple drones to take off with one click to perform collaborative operations for nuclear island containment video collection; Step 4.2: The drone transmits video data to the collaborative control platform in real time through the image transmission module to implement online detection of the outer wall of the containment vessel; if a drone is found to have a suspected display, the collaborative control platform will hover the corresponding drone at a fixed point to capture the high-resolution image of the display and judge the authenticity and nature of the display; Step 4.3: During the UAV containment video acquisition process, both the UAV end and the collaborative control platform end store the video data.

10. The method for detecting defects in the outer wall of a nuclear island containment vessel according to claim 1, characterized in that: Step 5 specifically includes: Step 5.1: The data collected by the camera, the flight trajectory parameters of the aircraft, and the three-dimensional model of the nuclear island are integrated on the collaborative control platform to generate the nuclear island containment video detection data; Step 5.2: Mark the nuclear island containment display area on the 3D model, extract the frame image of the corresponding defect video, establish a link between the mark and the defect image, and realize defect detection positioning and qualitative analysis; Step 5.3: During the drone containment video acquisition process, the size of the defect can be measured based on the camera model, and the defect location parameters and defect size are attached below the defect image for description to achieve quantitative analysis of the defect.

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