System and method for underwater measurement of heavy water reactor fuel bundle dimensions

Abstract

The application relates to the technical field of fuel rod bundle underwater size measurement, and provides a heavy water reactor fuel rod bundle underwater size measurement system and a measurement method. The heavy water reactor fuel rod bundle underwater size measurement system comprises a support platform, a rotating positioning mechanism, a three-dimensional moving mechanism, a first underwater measurement camera used for collecting overall images of the fuel rod bundle and images of single fuel elements, a camera measurement calibration platform comprising a rod bundle measurement calibration plate and an element measurement calibration plate, a first mirror assembly used for reflecting the images of the first end plate to the first underwater measurement camera, a camera movement module comprising two module guide rails and a camera support capable of sliding along the module guide rails, a second underwater measurement camera used for collecting images of a second end plate, and a second mirror assembly used for reflecting the images of the second end plate to the second underwater measurement camera. The moving platform and the underwater camera can be used for completing fuel rod bundle image collection and splicing, and the detection speed is high and the measurement precision is high.

Description

Technical Field

[0001] This application relates to the field of underwater dimension measurement technology for fuel rod bundles, and more specifically, to an underwater dimension measurement system and method for heavy water reactor fuel rod bundles. Background Technology

[0002] The CANDU-type heavy water reactor nuclear power plant is a pressure tube reactor with heavy water as the moderator and coolant, using natural uranium as fuel. It employs non-stop refueling and has very high economic value and additional application value. The fuel rod bundle, as the core fuel component of the CANDU-type heavy water reactor, has a simple and compact structure.

[0003] After the fuel rod bundles in a heavy water reactor are removed from the reactor, it is necessary to promptly obtain dimensional data such as the length of the fuel rod bundles, the curvature of the fuel rod bundles, the length of the fuel elements, the spacing between the fuel elements, and the diameter of the endplates underwater at the pool edge. These data are an important basis for conducting performance analysis of the fuel rod bundles after removal from the reactor. Performance analysis and evaluation is a key step in the research and development of zirconium materials and new cladding materials for heavy water reactor fuels.

[0004] Therefore, how to achieve accurate underwater measurement of fuel rod bundle length, fuel rod bundle curvature, fuel element length, fuel element spacing, and endplate diameter has become a technical challenge that urgently needs to be solved. Summary of the Invention

[0005] To address the technical challenges of accurately measuring the length, curvature, fuel element length, fuel element spacing, and endplate diameter of fuel rod bundles underwater, this application proposes a heavy water reactor fuel rod bundle underwater dimension measurement system in its first aspect.

[0006] The second aspect of this application also proposes a method for underwater dimension measurement of fuel rod bundles in heavy water reactors.

[0007] In view of this, the first aspect of this application proposes an underwater dimension measurement system for heavy water reactor fuel rod bundles. The fuel rod bundle includes multiple fuel elements and a first end plate and a second end plate disposed at both ends of the fuel elements. The underwater dimension measurement system for heavy water reactor fuel rod bundles includes: a support platform; a rotation positioning mechanism disposed on the support platform for clamping and driving the fuel rod bundle to rotate; a three-dimensional moving mechanism disposed on the support platform; a first underwater measurement camera disposed on the three-dimensional moving mechanism and driven by the three-dimensional moving mechanism to move in three-dimensional space for acquiring overall images of the fuel rod bundle and images of individual fuel elements; a camera measurement calibration platform disposed on the support platform, including a fuel rod bundle measurement calibration plate and an element measurement calibration plate; a first reflector assembly disposed on the support platform for reflecting the image of the first end plate to the first underwater measurement camera; a camera motion module disposed on the support platform, including two module guide rails and a camera bracket that can slide along the module guide rails; a second underwater measurement camera disposed on the camera bracket for acquiring images of the second end plate; and a second reflector assembly disposed on the camera bracket for reflecting the image of the second end plate to the second underwater measurement camera.

[0008] In conjunction with the first aspect, in some feasible implementations, the camera motion module further includes: a connecting base plate and a lead screw transmission mechanism; the connecting base plate is set on the support platform, and two module guide rails are arranged side by side on both sides of the connecting base plate; the lead screw transmission mechanism includes a lead screw, a lead screw support, an underwater motor, and a lead screw nut, the lead screw support is set on the connecting base plate, one end of the lead screw is connected to the underwater motor through a coupling, the other end of the lead screw is supported by the lead screw support, the lead screw is located between the two module guide rails, the lead screw nut is connected to the camera bracket, and the camera bracket slides with the module guide rails through a module slider.

[0009] In conjunction with the first aspect, in some feasible ways, the first reflector assembly includes: a reflector bracket disposed on a support platform; and an end plate reflector embedded in the reflector bracket at a preset angle.

[0010] In conjunction with the first aspect, in some feasible embodiments, the camera measurement calibration platform further includes: mounting legs, set on the support platform, the rod bundle measurement calibration plate set on the mounting legs and fixed by a pressure plate; and a support base, set on the pressure plate, the component measurement calibration plate set on the support base and fixed by a pressure strip.

[0011] In conjunction with the first aspect, in some feasible ways, the upper surface of the rod bundle measurement calibration plate is provided with a black and white checkered pattern, and the height of the upper surface of the rod bundle measurement calibration plate is flush with the center line of the fuel rod bundle; the upper surface of the element measurement calibration plate is provided with a black and white checkered pattern, and the height of the upper surface of the element measurement calibration plate is flush with the center line of the top fuel element of the fuel rod bundle.

[0012] The second aspect of this application proposes an underwater dimension measurement method for heavy water reactor fuel rod bundles, employing an underwater dimension measurement system for heavy water reactor fuel rod bundles as described in any of the above technical solutions, including the following steps: fixing the fuel rod bundle at an underwater rotating position; driving a first underwater measuring camera to move to a calibration plate area for camera calibration and obtaining pixel conversion coefficients; rotating the fuel rod bundle to a first angle, driving the first underwater measuring camera to move along the axial direction of the fuel rod bundle, and acquiring segmented images of the entire bundle; performing stitching and edge extraction based on the segmented images, and calculating the length and curvature of the fuel rod bundle at the first angle; rotating the fuel bundle to multiple different angles, and... Repeat the above image acquisition and calculation steps to complete multi-angle dimension measurement; drive the first underwater measuring camera to move to the calibration plate area and recalibrate the calibration plate; for each fuel element on the outer ring of the fuel rod bundle, rotate the fuel rod bundle in sequence and drive the first underwater measuring camera to move along the element axis, acquire images of individual fuel elements in segments, and calculate the length and spacing of each fuel element; reflect the image of the first end plate of the fuel rod bundle to the first underwater measuring camera through the first reflector assembly for image acquisition and diameter measurement; reflect the image of the second end plate of the fuel rod bundle to the second underwater measuring camera through the second reflector assembly for image acquisition and diameter measurement.

[0013] In conjunction with the second aspect, in some feasible methods, driving the first underwater measurement camera to move to the calibration plate area for camera calibration and obtaining pixel conversion coefficients includes: driving the first underwater measurement camera to move above the rod bundle measurement calibration plate; adjusting the height of the first underwater measurement camera so that its field of view completely covers the rod bundle measurement calibration plate; acquiring an image of the rod bundle measurement calibration plate, performing correction processing on the image, and calculating the pixel conversion coefficients to complete the rod bundle measurement calibration.

[0014] In conjunction with the second aspect, in some feasible ways, the first underwater measurement camera is moved to the calibration plate area to recalibrate the calibration plate, including: moving the first underwater measurement camera above the component measurement calibration plate; adjusting the height of the first underwater measurement camera so that the field of view of the first underwater measurement camera completely covers the component measurement calibration plate; acquiring an image of the component measurement calibration plate, performing image correction processing, and calculating the pixel conversion coefficient to complete the calibration for fuel element measurement.

[0015] In conjunction with the second aspect, in some feasible methods, the image of the first endplate of the fuel rod bundle is reflected to the first underwater measuring camera via the first reflector assembly for image acquisition and diameter measurement. This includes the following steps: activating the rotation positioning mechanism to clamp and limit the fuel rod bundle, and then releasing the two end limits; activating the three-dimensional movement mechanism to move the first underwater measuring camera directly above the endplate reflector, so that the image of the first underwater measuring camera covers the entire first endplate of the fuel rod bundle; activating the software system of the first underwater measuring camera to complete image acquisition and edge extraction of the first endplate of the fuel rod bundle; and operating the software system of the first underwater measuring camera to complete the appearance inspection and diameter measurement of the first endplate of the fuel rod bundle.

[0016] In conjunction with the second aspect, in some feasible ways, the image of the second endplate of the fuel rod bundle is reflected to the second underwater measuring camera via the second reflector assembly for image acquisition and diameter measurement, including the following steps: driving the second underwater measuring camera to move horizontally so that its field of view covers the second endplate of the fuel rod bundle; acquiring the reflected image of the second endplate and performing edge extraction processing; and completing the appearance inspection and diameter measurement of the second endplate based on the extracted edge features.

[0017] Compared with related technologies, this application has the following technical advantages:

[0018] The underwater dimension measurement system and process method for heavy water reactor fuel rod bundles provided in this application can complete the image acquisition and stitching of fuel rod bundles using a mobile platform and an underwater camera, and then complete the dimension measurement through edge extraction and pixel conversion. The system has a fast detection speed, high measurement accuracy, and can be traced back at any time using images. The system has a high degree of automation and integration, and is convenient and quick to operate.

[0019] Specifically, it can take pictures and acquire images of the surface and end plates of the fuel rod bundle at any angle underwater; it can achieve precise movement and positioning of the underwater camera, and through segmented photography at precise positions, the acquired images can be seamlessly stitched together; it can achieve photography and image acquisition of the end plates of the fuel rod bundle by two underwater cameras using a reflector; it can achieve length and curvature measurement of the fuel rod bundle at any angle; it can achieve length and spacing measurement of the 18 fuel elements on the outer ring of the fuel rod bundle; and it can achieve visual inspection and diameter measurement of the end plates of the fuel rod bundle.

[0020] Additional aspects and advantages of this application will become apparent in the following description or may be learned by practice of this application. Attached Figure Description

[0021] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0022] Figure 1A schematic diagram of the underwater dimension measurement system for heavy water reactor fuel rod bundles in one embodiment of this application is shown;

[0023] Figure 2 A schematic diagram of the structure of an underwater inspection platform according to one embodiment of this application is shown;

[0024] Figure 3 A schematic diagram of the structure of a first underwater measurement camera in one embodiment of this application is shown;

[0025] Figure 4 A schematic diagram of the camera motion module in one embodiment of this application is shown;

[0026] Figure 5 A schematic diagram of the camera measurement calibration platform in one embodiment of this application is shown;

[0027] Figure 6 A schematic diagram of the structure of a first reflector assembly in one embodiment of this application is shown;

[0028] Figure 7 A schematic diagram of the structure of a fuel rod bundle in one embodiment of this application is shown;

[0029] Figure 8 A schematic diagram of the structure of the second end plate of the fuel rod bundle in one embodiment of this application is shown;

[0030] Figure 9 One of the structural schematic diagrams of a rotary positioning mechanism according to one embodiment of this application is shown;

[0031] Figure 10 A second schematic diagram of the rotary positioning mechanism in one embodiment of this application is shown;

[0032] Figure 11 The third schematic diagram shows the structure of the rotary positioning mechanism in one embodiment of this application;

[0033] Figure 12 The fourth schematic diagram shows the structure of a rotary positioning mechanism in one embodiment of this application;

[0034] Figure 13 A schematic diagram of the rod bundle measurement process in one embodiment of this application is shown;

[0035] Figure 14 A schematic diagram of the endplate measurement process in one embodiment of this application is shown;

[0036] Figure 15 A flowchart illustrating an underwater dimension measurement method for heavy water reactor fuel rod bundles according to one embodiment of this application is shown.

[0037] in, Figures 1 to 12 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0038] 1. Underwater inspection platform, 2. Mounting support, 3. First underwater measuring camera, 4. Camera motion module, 5. Second underwater measuring camera, 6. Camera measuring and calibration platform, 7. First reflector assembly, 8. Fuel rod bundle;

[0039] 101 Three-dimensional moving mechanism, 102 Rotary positioning mechanism, 103 Support platform;

[0040] 301 Servo motor, 302 Worm gearbox, 303 First worm gear, 304 First turbine gear, 305 First universal joint, 306 First transmission rod, 307 Second universal joint, 308 Second transmission rod, 309 Base plate, 310 Third universal joint, 311 Second worm gear, 312 Worm gear seat, 313 Second turbine gear, 314 Fourth universal joint, 315 Turbine gear seat, 316 First irregular worm gear, 317 Second irregular worm gear 318 Fuel rod bundle support, 319 Underwater DC motor, 320 Coupling, 321 Transmission screw, 322 Transmission nut, 323 Screw support, 324 Connecting rod, 325 Clamping connecting rod, 326 Clamping disc, 327 First tension / compression sensor, 328 Limiting rod, 329 Rod bundle limiting block support, 330 Square head, 331 Gear, 332 Gear screw, 333 Rod bundle limiting block, 334 Limiting block sliding shaft;

[0041] 401 Connecting base plate, 402 Module guide rail, 403 Module slider, 404 Motion support plate, 405 Underwater motor, 406 Coupling, 407 Lead screw, 408 Lead screw support, 409 Camera bracket, 410 End plate reflector.

[0042] 601 Mounting support leg, 602 Rod bundle measurement calibration plate, 603 Pressure plate, 604 Support base, 605 Component measurement calibration plate, 606 Pressure strip;

[0043] 701 Reflector bracket, 702 End plate reflector, 703 Reflector trim strip;

[0044] 801 Fuel element, 802 Support pad, 803 Second end plate. Detailed Implementation

[0045] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0046] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0047] The following reference Figures 1 to 15 This application describes an underwater dimension measurement system and method for heavy water reactor fuel rod bundles according to some embodiments.

[0048] like Figure 1 , Figure 2 , Figure 3 , Figure 7 and Figure 8 As shown, the first aspect of this application provides an underwater dimension measurement system for a heavy water reactor fuel rod bundle. The fuel rod bundle 8 includes multiple fuel elements 801 and a first end plate and a second end plate 803 disposed at both ends of the fuel elements 801. The underwater dimension measurement system for the heavy water reactor fuel rod bundle includes: a support platform 103; a rotation positioning mechanism 102, disposed on the support platform 103, for clamping and driving the fuel rod bundle 8 to rotate; a three-dimensional moving mechanism 101, disposed on the support platform 103; and a first underwater measuring camera 3, disposed on the three-dimensional moving mechanism 101, driven by the three-dimensional moving mechanism 101 to move in three-dimensional space, for acquiring overall images of the fuel rod bundle 8 and individual fuel elements 801. The image is captured by the camera; a camera measurement calibration platform 6, mounted on the support platform 103, includes a rod bundle measurement calibration plate 602 and a component measurement calibration plate 605; a first reflector assembly 7, mounted on the support platform 103, is used to reflect the image of the first end plate to the first underwater measurement camera 3; a camera motion module 4, mounted on the support platform 103, includes two module guide rails 402 and a camera bracket 409 that can slide along the module guide rails 402; a second underwater measurement camera 5, mounted on the camera bracket 409, is used to acquire the image of the second end plate 803; and a second reflector assembly, mounted on the camera bracket 409, is used to reflect the image of the second end plate 803 to the second underwater measurement camera 5.

[0049] The underwater dimension measurement system for heavy water reactor fuel rod bundles provided in this application includes a support platform 103, a rotation positioning mechanism 102, a three-dimensional moving mechanism 101, a first underwater measuring camera 3, a camera measuring and calibration platform 6, a first reflector assembly 7, a camera motion module 4, a second underwater measuring camera 5, and a second reflector assembly.

[0050] By setting up a first underwater measuring camera 3 to acquire overall images of the fuel rod bundle 8 and images of individual fuel elements 801, and a second underwater measuring camera 5 to acquire images of the second endplate 803, and combining the images of the first endplate and the second endplate 803 reflected to the corresponding cameras by the first reflector assembly 7 and the second reflector assembly respectively, information on different parts of the fuel rod bundle 8 can be comprehensively obtained. This enables precise underwater measurement of multiple key dimensions such as the length of the fuel rod bundle 8, the curvature of the fuel rod bundle 8, the length of the fuel elements 801, the spacing between the fuel elements 801, and the diameter of the endplate, effectively solving the problem that traditional methods are difficult to measure comprehensively and accurately.

[0051] The rotary positioning mechanism 102 can clamp and drive the fuel rod bundle 8 to rotate, the three-dimensional moving mechanism 101 can drive the first underwater measuring camera 3 to move in three-dimensional space, and the camera bracket 409 can slide along the module guide rail 402, which makes the measurement system highly flexible and adjustable. It can flexibly adjust the measurement position and angle according to different measurement needs and the actual state of the fuel rod bundle 8, so as to ensure the accuracy and reliability of the measurement data.

[0052] The camera measurement calibration platform 6 is equipped with a rod bundle measurement calibration plate 602 and a component measurement calibration plate 605, which can accurately calibrate the measuring camera, eliminate the influence of camera errors and measurement environment factors on the measurement results, further improve the accuracy and stability of the measurement, and ensure the accuracy and consistency of the measurement data.

[0053] The first underwater measuring camera 3 and the second underwater measuring camera 5 have built-in image processing software that can stitch together segmented images.

[0054] like Figure 9 , Figure 10 , Figure 11 and Figure 12As shown, the rotary positioning mechanism 102 includes a rotary shaft waterproof servo motor 301, a worm gear box 302, a first worm gear 303, a first turbine gear 304, a first universal joint 305, a first transmission rod 306, a second universal joint 307, a second transmission rod 308, a base plate 309, a third universal joint 310, a second worm gear 311, a worm gear seat 312, a second turbine gear 313, a fourth universal joint 314, a turbine seat 315, a first irregular worm gear 316, and a second... The system includes two irregularly shaped worm gears 317, a fuel rod bundle support 318, an underwater DC motor 319, a coupling 320, a transmission screw 321, a transmission nut 322, a screw support 323, a connecting rod 324, a clamping connecting rod 325, a clamping plate 326, a first tension / compression sensor 327, a limit rod 328, a rod bundle limit block support 329, a square head 330, a gear 331, a gear screw 332, a rod bundle limit block 333, and a limit block sliding shaft 334. A rotating shaft waterproof servo motor 301 is connected to the first worm gear 303 via a coupling and is mounted on a worm gear box 302. The worm gear box 302 drives the first worm gear 303 to rotate within it, and a first worm 304 meshes with the first worm gear 303. One end of the first drive rod 306 is connected to the first turbine 304 via a first universal joint 305, and the other end is connected to the second worm 311 via a third universal joint 310. The second worm 311 is installed in a worm seat 312 and meshes with the second turbine 313. The second turbine 313 is connected to the shaft of the second irregular worm 317 via a drive key. The other end of the second irregular worm 317 is connected to the shaft of the first irregular worm 316 via a fourth universal joint 314. The two irregular turbines are supported by a turbine seat 315, which is mounted on a fuel rod bundle support 318 with screws. One end of the second drive rod 308 is connected to the second worm 311 via a second universal joint 307, and the other end is connected to the symmetrically installed irregular turbines. The two fuel rod bundle supports 318 are symmetrically installed on a base plate 309. When the waterproof servo motor 301 rotates, it drives the symmetrically mounted irregular turbine, the first irregular worm 316, and the second irregular worm 317 to rotate simultaneously through the meshing transmission of the worm gear and the transmission of two universal joints. The first irregular worm 316 and the second irregular worm 317 mesh with the support pad 802 in the fuel rod bundle 8, driving the fuel rod bundle 8 to rotate around the axis. The underwater DC motor 319 is connected to one end of the transmission screw 321 through the coupling 320. The other end of the transmission screw 321 is supported on the screw support 323. The transmission nut 322 meshes with the transmission screw 321 and is connected to the clamping connecting rod 325 through a hinge. The middle of the clamping connecting rod 325 is connected to the connecting rod 324 through a hinge. The clamping plate 326 is mounted on the first tension and pressure sensor 327 with screws. The bottom of the first tension and pressure sensor 327 is mounted on the clamping connecting rod 325 with screws. The limit rod 328 is mounted on both sides of the screw support 323.When the underwater DC motor 319 rotates, it drives the clamping linkage 325 to pitch, thereby clamping and releasing one end plate of the fuel rod bundle 8 using the clamping disc 326. The first tension / compression sensor 327 provides real-time feedback on the pressure value during clamping. If the pressure exceeds the limit, the operation will stop, providing protection. When the clamping disc 326 is released, the limit rod 328 acts as a limit to prevent the linkage mechanism from reaching the dead point. The rod bundle limit block 333 is fitted onto the limit block sliding shaft 334 and meshes with the gear screw 332. The lower gear of the gear screw 332 meshes with the gear 331. The limit block sliding shaft 334 and the gear screw 332 are supported on the rod bundle limit block support 329. The square head 330 is connected to the gear 331 via a key. When the square head 330 is rotated using a sleeve tool, it can drive the rod bundle limit block 333 to rise and fall. When the rod bundle limiting block 333 is raised, it clamps one end plate of the fuel rod bundle 8, while the other end plate is limited by the rod bundle limiting block 333. The limiting is canceled after the rod bundle limiting block 333 is lowered.

[0055] The three-dimensional moving mechanism 101 includes an X-axis moving module, a Y-axis moving module, and a Z-axis moving module, enabling independent and flexible movement in three orthogonal directions. Equipment mounted on it can be precisely positioned in three-dimensional space, meeting the needs of inspecting different positions of the fuel rod bundle. Movement and adjustment in both horizontal and vertical directions are more convenient and precise, improving operational flexibility and the comprehensiveness of inspection.

[0056] The underwater dimensional measurement system for heavy water reactor fuel rod bundles provided in this application is specifically designed for underwater environments. All components can operate normally underwater, overcoming the difficulties posed by the complex underwater environment and providing a reliable technical means for dimensional measurement of the heavy water reactor fuel rod bundle 8 in underwater conditions. Using a three-dimensional moving mechanism 101, a first underwater measuring camera 3, and a second underwater measuring camera 5, images of the fuel rod bundle 8 can be acquired and stitched together. Dimensional measurement is then completed through edge extraction and pixel conversion. The system offers fast detection speed, high measurement accuracy, and allows for real-time image review. It also features high automation and integration, and is convenient and quick to operate.

[0057] like Figure 4As shown, in some embodiments provided in this application, the camera motion module 4 further includes: a connecting base plate 401 and a lead screw transmission mechanism; the connecting base plate 401 is disposed on the support platform 103, and two module guide rails 402 are disposed side by side on both sides of the connecting base plate 401; the lead screw transmission mechanism includes a lead screw 407, a lead screw support 408, an underwater motor 405, and a lead screw nut, the lead screw support 408 is disposed on the connecting base plate 401, one end of the lead screw 407 is connected to the underwater motor 405 through a coupling 406, the other end of the lead screw 407 is supported by the lead screw support 408, the lead screw 407 is located between the two module guide rails 402, the lead screw nut is connected to the camera bracket 409, and the camera bracket 409 slides with the module guide rails 402 through a module slider 403.

[0058] In this embodiment, the camera motion module 4 also includes a connecting base plate 401 and a lead screw transmission mechanism. The engagement of the lead screw 407 and the lead screw nut enables the underwater motor 405 to be precisely converted into linear motion, thereby driving the camera bracket 409 to make precise linear displacement along the module guide rail 402. The precise transmission method of the lead screw transmission mechanism allows the second underwater measuring camera 5 to accurately reach the preset measurement position, ensuring the positional accuracy of acquiring the image of the second end plate 803, and thus improving the accuracy of measuring the size of the fuel rod bundle 8.

[0059] The lead screw support 408 provides stable support for the lead screw 407, reducing vibration and deformation of the lead screw 407 during transmission. Meanwhile, the camera bracket 409 slides against the module guide rail 402 via the module slider 403, ensuring smooth movement of the camera bracket 409 and effectively limiting its direction of movement. This keeps the camera bracket 409 stable during movement, preventing swaying or deviation from affecting the imaging quality and measurement accuracy of the second underwater measuring camera 5.

[0060] Two module guide rails 402 are arranged side by side on both sides of the connecting base plate 401, with a lead screw 407 located between the two module guide rails 402. This layout makes full use of space, resulting in a compact and rationally designed camera motion module 4. By controlling the operation of the underwater motor 405, the position of the camera bracket 409 can be easily adjusted, thereby changing the shooting position of the second underwater measuring camera 5. This allows the measurement system to adapt to fuel rod bundles 8 of different sizes and shapes, as well as different measurement requirements.

[0061] The connecting base plate 401 securely mounts the entire camera motion module 4 onto the support platform 103, enhancing the module's stability underwater. Under the influence of underwater currents, pressure, and other external forces, the connecting base plate 401 effectively resists these forces, ensuring that the relative positions of the module's components remain unchanged. This allows the second underwater measuring camera 5 to operate stably and continuously acquire high-quality image data, providing a reliable basis for measuring the dimensions of the fuel rod bundle 8.

[0062] like Figure 6 As shown, in some embodiments provided in this application, the first reflector assembly 7 includes: a reflector bracket 701, disposed on the support platform 103; and an end plate reflector 702, embedded in the reflector bracket 701 at a preset angle.

[0063] In this embodiment, the first reflector assembly 7 includes a reflector bracket 701 and an endplate reflector 702. The reflector bracket 701 is securely mounted on the support platform 103, providing reliable support for the endplate reflector 702 and ensuring its stable position in complex underwater environments. It prevents displacement due to water flow impacts or equipment vibrations, thus guaranteeing the stability and accuracy of the reflected image. The endplate reflector 702 is embedded in the reflector bracket 701 at a preset angle, accurately reflecting the image from the first endplate to the first underwater measuring camera 3. This allows the camera to acquire a clear image without directly facing the endplate, optimizing the camera layout and saving underwater space. The preset angle can be 45 degrees.

[0064] The first reflector assembly 7 has a simple structure, is easy to install and maintain, reduces the overall complexity and cost of the system, and improves the reliability and durability of the system. It helps to ensure long-term stable operation underwater and provides strong support for accurately measuring the relevant dimensions of the fuel rod bundle 8.

[0065] The second reflector assembly has a structure similar to that of the first reflector assembly 7.

[0066] like Figure 5 As shown, in some embodiments provided in this application, the camera measurement calibration platform 6 further includes: a mounting leg 601, disposed on the support platform 103, a rod bundle measurement calibration plate 602 disposed on the mounting leg 601 and fixed by a pressure plate 603; a support base 604, disposed on the pressure plate 603, and a component measurement calibration plate 605 disposed on the support base 604 and fixed by a pressure strip 606.

[0067] In this embodiment, the camera measurement calibration platform 6 also includes mounting legs 601 and a support base 604. The mounting legs 601 securely mount the rod bundle measurement calibration plate 602 on the support platform 103, providing a reliable foundation support for the rod bundle measurement calibration plate 602, ensuring that it remains in a fixed position in complex measurement environments and will not shift or shake due to external interference, thereby ensuring the accuracy and stability of the calibration data.

[0068] The rod bundle measurement calibration plate 602 is fixed by the pressure plate 603. This fixing method is simple and reliable, effectively preventing the calibration plate from loosening and facilitating installation and disassembly. When maintenance, replacement, or adjustment of the calibration plate is required, operators can complete the task quickly and conveniently, improving work efficiency.

[0069] A support base 604 is mounted on a pressure plate 603, and a component measurement calibration plate 605 is mounted on the support base 604 and fixed by a pressure strip 606. The support base 604 can adjust the height and angle of the component measurement calibration plate 605 according to actual measurement needs, better matching it to the measurement scenario and improving measurement accuracy and flexibility. The fixing method of the pressure strip 606 ensures that the component measurement calibration plate 605 will not shift during measurement, guaranteeing the reliability of the measurement data.

[0070] The camera measurement and calibration platform 6 has a reasonable structure, is easy to install, and has high stability. It can provide an accurate calibration benchmark for the underwater visual inspection system and effectively improve the accuracy and reliability of various dimensional measurements of the fuel rod bundle 8.

[0071] In some embodiments provided in this application, the upper surface of the rod bundle measurement calibration plate 602 is provided with a black and white checkered pattern, and the height of the upper surface of the rod bundle measurement calibration plate 602 is flush with the center line of the fuel rod bundle 8; the upper surface of the element measurement calibration plate 605 is provided with a black and white checkered pattern, and the height of the upper surface of the element measurement calibration plate 605 is flush with the center line of the top fuel element 801 of the fuel rod bundle 8.

[0072] In this embodiment, both the rod bundle measurement calibration plate 602 and the component measurement calibration plate 605 have a black and white checkered pattern on their upper surfaces. This pattern has high contrast and can provide clear and distinct feature points for the camera, making it easier for the camera to accurately identify and position the components, effectively improving the accuracy of the measurement calibration and reducing measurement errors.

[0073] The upper surface of the fuel rod bundle measurement calibration plate 602 is flush with the center line of the fuel rod bundle 8, so that when the camera is calibrating by acquiring images, it can operate with the same viewing angle and height reference as the overall size of the fuel rod bundle 8, ensuring the consistency and reliability of the measurement data.

[0074] The upper surface of the component measurement calibration plate 605 is aligned with the centerline of the fuel element 801 at the top of the fuel rod bundle 8, providing the camera with an accurate reference height when measuring the relevant dimensions of a single fuel element 801, enabling precise acquisition of the element's position and size information. Together, these two components allow for comprehensive and accurate dimensional measurement and calibration of the fuel rod bundle 8 and its components, providing a solid foundation for subsequent accurate measurements.

[0075] like Figure 15 As shown, the second aspect of this application provides a method for underwater dimension measurement of heavy water reactor fuel rod bundles, employing the underwater dimension measurement system for heavy water reactor fuel rod bundles in any of the above embodiments, including the following steps:

[0076] S202: Secure the fuel rod bundle to the underwater rotating position;

[0077] S204: Drive the first underwater measurement camera to the calibration plate area for camera calibration and obtain pixel conversion coefficients;

[0078] S206: Rotate the fuel rod bundle to the first angle, drive the first underwater measurement camera to move along the axial direction of the fuel rod bundle, and acquire the overall image of the rod bundle in segments;

[0079] S208: Based on segmented images, stitch together and extract edges to calculate the length and curvature of the fuel rod bundle at the first angle;

[0080] S210: Rotate the fuel rod bundle to multiple different angles, repeat the above image acquisition and calculation steps, and complete the multi-angle dimension measurement;

[0081] S212: Drive the first underwater measuring camera to the calibration plate area and recalibrate the calibration plate;

[0082] S214: For each fuel element on the outer ring of the fuel rod bundle, rotate the fuel rod bundle in sequence and drive the first underwater measuring camera to move along the element axis, collect images of individual fuel elements in segments, and calculate the length and spacing of each fuel element;

[0083] S216: The image of the first end plate of the fuel rod bundle is reflected to the first underwater measuring camera through the first reflector assembly for image acquisition and diameter measurement;

[0084] S218: The image of the second end plate of the fuel rod bundle is reflected to the second underwater measuring camera through the second reflector assembly for image acquisition and diameter measurement.

[0085] The underwater dimensional measurement method for heavy water reactor fuel rod bundles provided in this application fixes the fuel rod bundle in an underwater rotating position and drives a first underwater measuring camera to perform multi-step operations. First, pixel conversion coefficients are calibrated and obtained. Then, the overall image of the fuel rod bundle is acquired segment by segment and stitched together to extract edges. This method can accurately calculate the length and curvature of the fuel rod bundle at a first angle. Repeated measurements at multiple different angles provide a comprehensive understanding of the fuel rod bundle's dimensional information, reducing measurement errors and improving the reliability of the results. Specifically, any fuel element in the fuel rod bundle is marked as the first fuel element. The fuel rod bundle is rotated, and the angle at which the first fuel element reaches the top position is the first angle.

[0086] For each fuel element on the outer ring of the fuel rod bundle, the bundle is rotated sequentially and the camera is driven to acquire images of individual elements in segments. This allows for the precise calculation of the length and spacing of each fuel element, meeting the requirements for fine measurement of the individual dimensions of the fuel elements.

[0087] The images of the two end plates of the fuel rod bundle are reflected to the corresponding cameras by the first and second reflector assemblies, respectively, for acquisition and diameter measurement. This eliminates the need for the camera to be directly facing the end plates, optimizes the camera layout, saves underwater space, and ensures the accuracy and stability of the measurement.

[0088] The underwater dimensional measurement method for heavy water reactor fuel rod bundles provided in this application first performs camera calibration to ensure the accuracy of the measurement benchmark, and then gradually carries out various dimensional measurements. Furthermore, it recalibrates as needed at different measurement stages to further ensure measurement accuracy. The entire measurement method is adaptable to complex underwater environments and can provide comprehensive, accurate, and reliable dimensional data support for the quality inspection and safety assessment of heavy water reactor fuel rod bundles.

[0089] In some embodiments provided in this application, driving the first underwater measurement camera to move to the calibration plate area for camera calibration and obtaining pixel conversion coefficients includes the following steps: driving the first underwater measurement camera to move above the rod bundle measurement calibration plate; adjusting the height of the first underwater measurement camera so that its field of view completely covers the rod bundle measurement calibration plate; acquiring an image of the rod bundle measurement calibration plate, performing correction processing on the image, and calculating the pixel conversion coefficients to complete the rod bundle measurement calibration.

[0090] In this embodiment, the first underwater measuring camera is driven to move precisely above the rod bundle measuring calibration plate, laying the foundation for subsequent accurate calibration, ensuring the correct starting position of the calibration operation, and avoiding the impact of position deviation on calibration accuracy.

[0091] Adjusting the camera height to ensure the field of view completely covers the calibration board is an operation that takes into account the differences in various measurement scenarios and camera performance. By flexibly adjusting the height, it is possible to adapt to various actual situations, ensuring that all feature information on the calibration board can be completely acquired by the camera, making the calibration data more comprehensive and representative.

[0092] After acquiring the calibration plate image, correction processing is performed to effectively eliminate interference factors such as distortion and noise in the image, improve image quality, and thus enhance the accuracy of the calibration results. Finally, the pixel conversion coefficient is calculated to complete the fuel rod bundle measurement calibration. This coefficient can accurately convert the pixel size in the image into the actual physical size, providing a reliable conversion basis for subsequent accurate measurement of dimensional parameters such as the length and curvature of the fuel rod bundle. This helps to improve the measurement accuracy and reliability of the entire underwater dimensional measurement system, ensuring that the measurement results truly reflect the actual situation of the fuel rod bundle.

[0093] In some embodiments provided in this application, driving the first underwater measurement camera to move to the calibration plate area and recalibrating the calibration plate includes the following steps: driving the first underwater measurement camera to move above the component measurement calibration plate; adjusting the height of the first underwater measurement camera so that the field of view of the first underwater measurement camera completely covers the component measurement calibration plate; acquiring an image of the component measurement calibration plate, performing image correction processing, and calculating the pixel conversion coefficient to complete the calibration for fuel element measurement.

[0094] In this embodiment, the first underwater measurement camera is driven to move accurately above the component measurement calibration plate, providing a precise starting position for subsequent operations. This ensures that the calibration process begins from the correct reference point, effectively avoiding the problem of inaccurate calibration data due to positional deviation, and laying a good foundation for accurate measurement of fuel element dimensions.

[0095] Secondly, it is flexible and adaptable to diverse scenarios. Adjusting the camera height ensures the field of view fully covers the component measurement calibration board, a design that fully considers the complexity and diversity of actual measurement environments. It can be flexibly adjusted according to different situations, ensuring that all key features on the calibration board are clearly captured by the camera, making the calibration data more comprehensive and representative, and enhancing the reliability of the calibration results.

[0096] Finally, calibration processing improves calibration accuracy. After image acquisition, calibration processing eliminates distortion, noise, and other interference factors, improving image quality. Based on this, the calculated pixel conversion coefficients are more accurate, precisely converting image pixel dimensions into actual physical dimensions. This improves the accuracy of measurements of fuel element length, spacing, and other dimensions, ensuring that measurement results accurately reflect the actual state of the fuel elements.

[0097] In some embodiments provided in this application, the image of the first endplate of the fuel rod bundle is reflected to the first underwater measuring camera by the first reflector assembly for image acquisition and diameter measurement, including the following steps: activating the rotation positioning mechanism to clamp and limit the fuel rod bundle, and then releasing the two end limits; activating the three-dimensional moving mechanism to move the first underwater measuring camera directly above the endplate reflector, so that the image of the first underwater measuring camera covers the entire first endplate of the fuel rod bundle; activating the first underwater measuring camera software system to complete the image acquisition and edge extraction of the first endplate of the fuel rod bundle; and operating the first underwater measuring camera software system to complete the appearance inspection and diameter measurement of the first endplate of the fuel rod bundle.

[0098] In this embodiment, activating the rotary positioning mechanism and clamping the limits effectively secures the fuel rod bundle, preventing displacement during measurement due to water flow impact or its own swaying, thus ensuring measurement stability. Releasing the limits at both ends facilitates subsequent fine-tuning operations, making the measurement process more flexible.

[0099] The three-dimensional moving mechanism is activated to precisely move the first underwater measuring camera to the top of the endplate reflector, ensuring that the camera image covers the entire first endplate. This operation makes full use of space and, through precise positioning and movement control, enables the camera to acquire images of the endplate from the best angle and range, avoiding the loss of image information due to incomplete shooting range or poor angle, and providing a high-quality image foundation for accurate measurement.

[0100] The first underwater measurement camera software system is activated to complete image acquisition and edge extraction, enabling rapid and accurate acquisition of the endplate contour information, providing crucial data for subsequent visual inspection and diameter measurement. Visual inspection using the software system can promptly detect defects and damage on the endplate surface, ensuring the quality and safety of the fuel bundle. The diameter measurement function accurately obtains the endplate's dimensional parameters, providing vital data support for fuel bundle assembly and operation, and contributing to improved operational stability and safety of the entire heavy water reactor system.

[0101] In some embodiments provided in this application, the image of the second endplate of the fuel rod bundle is reflected to the second underwater measuring camera by the second reflector assembly for image acquisition and diameter measurement, including the following steps: driving the second underwater measuring camera to move horizontally so that its field of view covers the second endplate of the fuel rod bundle; acquiring the reflected image of the second endplate and performing edge extraction processing; and completing the appearance inspection and diameter measurement of the second endplate based on the extracted edge features.

[0102] In this embodiment, for camera positioning, the second underwater measuring camera is driven to move horizontally so that its field of view covers the second endplate. This horizontal movement method is simple to operate and provides accurate positioning. By precisely controlling the movement distance and direction, the camera can be quickly adjusted to a suitable position, ensuring that the endplate is completely within the field of view. This avoids the loss of image information due to inaccurate positioning and lays the foundation for subsequent accurate measurements.

[0103] In the image acquisition and processing stage, reflected images of the second endplate are acquired and edge extraction is performed. Reflective imaging cleverly solves the problem of the camera being unable to directly shoot at the endplate, saving underwater space and reducing equipment layout complexity. Edge extraction technology can accurately identify the contour boundaries of the endplate, effectively remove noise and interference information from the image, and obtain clear and accurate edge features, greatly improving image quality.

[0104] In measurement applications, the extracted edge features enable visual inspection and diameter measurement, quickly identifying defects such as scratches, cracks, and deformations on the endplate surface, ensuring the quality and safety of the fuel rod bundle. Simultaneously, precise edge data provides a reliable basis for diameter measurement, accurately calculating the endplate diameter. This provides crucial parameters for fuel rod bundle assembly and operational monitoring, contributing to improved stability and reliability of the entire heavy water reactor system.

[0105] like Figures 1 to 15 As shown in the specific embodiment, this application provides an underwater dimension measurement system and method for heavy water reactor fuel rod bundles. Taking a heavy water reactor fuel rod bundle 8 as the inspection object, the system measures the length of the fuel rod bundle 8, the curvature of the fuel rod bundle 8, the length of the fuel elements 801, the spacing between the fuel elements 801, and the diameter of the end plates. The fuel rod bundle 8 consists of fuel elements 801, support pads 802, and end plates. The support pads 802 are welded to the surface of 18 fuel elements 801 on the outer ring of the fuel rod bundle 8. The fuel elements 801 are connected and fixed to the end plates on both sides by end resistance welding. The underwater dimension measurement system for heavy water reactor fuel rod bundles includes: an underwater inspection platform 1, a mounting bracket 2, a first underwater measuring camera 3, a camera motion module 4, a second underwater measuring camera 5, a camera measurement calibration platform 6, a first reflector assembly 7, a second reflector assembly, and the fuel rod bundle 8.

[0106] The underwater inspection platform 1 includes a three-dimensional moving mechanism 101, a rotation positioning mechanism 102, and a support platform 103. The three-dimensional moving mechanism 101 and the rotation positioning mechanism 102 are respectively installed on the plane of the support platform 103 by fastening screws. The three-dimensional moving mechanism 101 provides the first underwater measuring camera 3 with movement and positioning in the X / Y / Z directions, and the rotation positioning mechanism 102 provides the fuel rod bundle 8 with rotation and angular positioning. The two mechanisms are independent and do not interfere with each other.

[0107] Mounting bracket 2 is mounted on the three-dimensional moving mechanism 101 by fastening screws. The first underwater measurement camera 3 is vertically connected to the mounting bracket 2 via a flange and fixed by screws. The three-dimensional moving mechanism 101 can drive the first underwater measurement camera 3 to move and position in the X / Y / Z directions, covering the area of ​​the camera measurement calibration platform 6 and the fuel rod bundle 8.

[0108] The camera motion module 4 includes a connecting base plate 401, module guide rails 402, module sliders 403, motion support plate 404, underwater motor 405, coupling 406, lead screw 407, lead screw support 408, camera bracket 409, and end plate reflector 410. The connecting base plate 401 is mounted on the support platform 103 via oblong holes on both sides and secured with screws. Two module guide rails 402 are symmetrically mounted on both sides of the connecting base plate 401 using screws. Two module sliders 403 slide on the two module guide rails 402 respectively. One end of the lead screw 407 is connected to the underwater motor 405 via the coupling 406, and the other end is supported by the lead screw support 408. The top surface of the lead screw nut on the lead screw 407 is connected to the base plate of the camera bracket 409 via screws. The two sides of the base plate of the camera bracket 409 are connected to the module sliders 403 via screws. The end plate reflector 410 is embedded in the camera bracket 409 at a 45-degree angle. The second underwater measurement camera 5 is vertically connected to the camera bracket 409 via a flange and fixed with screws. When the underwater motor 405 rotates, it can drive the second underwater measurement camera 5 to move and position horizontally. The end plate reflector 410 can reflect the image of the fuel rod bundle 8 second end plate 803 into the second underwater measurement camera 5.

[0109] The camera measurement calibration platform 6 includes mounting legs 601, a rod bundle measurement calibration plate 602, pressure plates 603, support bases 604, component measurement calibration plates 605, and pressure strips 606. The mounting legs 601 are connected to the support platform 103 via bottom slots and are fixed with screws. The rod bundle measurement calibration plate 602 is placed on the mounting legs 601 and pressed and fixed by the pressure plates 603 on both sides. The upper surface of the rod bundle measurement calibration plate 602 has a black and white checkered pattern, and its height is flush with the centerline of the fuel rod bundle 8. When the first underwater measurement camera 3 measures the length and curvature of the fuel rod bundle 8, the rod bundle measurement calibration plate 602 is used to calibrate the first underwater measurement camera 3, calculate pixel conversion coefficients, and perform image correction. The support base 604 is mounted on the side pressure plate 603 of the rod bundle measurement calibration plate 602 by screws. The component measurement calibration plate 605 is placed on the support base 604 and pressed and fixed by the pressure strips 606 on both sides. The upper surface of the component measurement calibration plate 605 has a black and white checkered pattern. The height of the upper surface of the component measurement calibration plate 605 is flush with the center line of the top fuel element 801 of the fuel rod bundle 8. When the first underwater measurement camera 3 measures the length of the fuel element 801 and the spacing between the fuel elements 801, the component measurement calibration plate 605 is used to calibrate the first underwater measurement camera 3, calculate the pixel conversion coefficient, and perform image correction.

[0110] The first reflector assembly includes a reflector bracket 701, an endplate reflector 702, and reflector retaining strips 703. The reflector bracket 701 is connected to the support platform 103 via a bottom oblong hole and is fixed in place by screws. The endplate reflector 702 is embedded in the reflector bracket 701 at a 45-degree angle and is pressed and fixed by the reflector retaining strips 703 on both sides. The endplate reflector 702 can reflect the image of the first endplate of the fuel rod bundle 8 into the first underwater measuring camera 3.

[0111] The underwater dimensional measurement method for fuel rod bundles consists of two parts: the bundle measurement process and the endplate measurement process.

[0112] like Figure 13 As shown, the rod bundle measurement process includes the following steps:

[0113] (1) Grab the fuel rod bundle and place it on the inspection station of the rotary positioning mechanism;

[0114] (2) Start the rotary positioning mechanism to clamp and limit the fuel rod bundle;

[0115] (3) Start the three-dimensional moving mechanism, adjust the X / Y value so that the first underwater measuring camera is positioned directly above the rod bundle measuring calibration plate, and then adjust the Z value so that the image of the first underwater measuring camera covers the entire rod bundle measuring calibration plate.

[0116] (4) Start the first underwater measurement camera software system, acquire the image of the rod bundle measurement calibration plate and correct the image, and calculate the pixel conversion coefficient to complete the rod bundle measurement calibration;

[0117] (5) Start the rotary positioning mechanism to rotate the fuel rod bundle to the 0-degree position;

[0118] (6) Start the three-dimensional moving mechanism, move the first underwater measuring camera until the center line of the fuel rod bundle is in the center of the camera screen, and then complete the overall segmented photography and acquisition of the fuel rod bundle along the axial direction of the fuel rod bundle;

[0119] (7) Start the software system of the first underwater measurement camera to complete the segmented image stitching and edge extraction of the fuel rod bundle;

[0120] (8) Operate the software system of the first underwater measuring camera to complete the measurement of the fuel rod bundle length at this angle;

[0121] (9) Operate the software system of the first underwater measuring camera to complete the measurement of the bending degree of the fuel rod bundle at this angle;

[0122] (10) Repeat steps (5) to (9), rotating the fuel rod bundle 90 degrees each time to complete the length and curvature measurement of the fuel rod bundle at four angles;

[0123] (11) Start the three-dimensional moving mechanism, adjust the X / Y value so that the first underwater measuring camera is positioned directly above the component measuring calibration plate, and then adjust the Z value so that the image of the first underwater measuring camera covers the entire component measuring calibration plate.

[0124] (12) Start the software system of the first underwater measurement camera, acquire the image of the component measurement calibration plate and correct the image, and calculate the pixel conversion coefficient to complete the component measurement calibration;

[0125] (13) Start the three-dimensional moving mechanism, move the first underwater measuring camera until the center line of the fuel element is in the center of the camera screen, and then complete the overall segmented photography and acquisition of the fuel element along the axial direction of the fuel element;

[0126] (14) Start the software system of the first underwater measurement camera to complete the segmented image stitching and edge extraction of the fuel element;

[0127] (15) Operate the software system of the first underwater measuring camera to complete the fuel element length measurement;

[0128] (16) Operate the software system of the first underwater measurement camera to complete the fuel element spacing measurement;

[0129] (17) Start the rotary positioning mechanism to rotate the fuel rod bundle by 20 degrees;

[0130] (18) Repeat steps (12) to (17), rotating the fuel rod bundle by 20 degrees each time to complete the measurement of the length and spacing of the 18 fuel elements on the outer ring of the fuel rod bundle;

[0131] (19) Start the rotary positioning mechanism, loosen the clamping limit, and grab the fuel rod bundle away from the rotary positioning mechanism inspection station.

[0132] like Figure 14 As shown, the endplate measurement process includes the following steps:

[0133] (1) Grab the fuel rod bundle and place it on the inspection station of the rotary positioning mechanism;

[0134] (2) Start the rotary positioning mechanism to clamp and limit the fuel rod bundle, and then release the limits at both ends;

[0135] (3) Start the three-dimensional moving mechanism and move the first underwater measurement camera to the top of the end plate reflector so that the image of the first underwater measurement camera covers the entire first end plate of the fuel rod bundle;

[0136] (4) Start the software system of the first underwater measurement camera to complete the image acquisition and edge extraction of the first end plate of the fuel rod bundle;

[0137] (5) Operate the software system of the first underwater measurement camera to complete the appearance inspection and diameter measurement of the first end plate of the fuel rod bundle;

[0138] (6) Start the underwater motor of the camera motion module to rotate and move the second underwater measuring camera horizontally until the screen covers the entire second end plate of the fuel rod bundle;

[0139] (7) Start the software system of the second underwater measurement camera to complete the image acquisition and edge extraction of the second end plate of the fuel rod bundle;

[0140] (8) Operate the software system of the second underwater measurement camera to complete the appearance inspection and diameter measurement of the second end plate of the fuel rod bundle;

[0141] (9) Grab the fuel rod bundle away from the rotary positioning mechanism and check the work station.

[0142] Specific Implementation Example (I): Fuel Rod Bunch Measurement:

[0143] Step 1: Grab the fuel rod bundle and place it on the inspection station of the rotary positioning mechanism;

[0144] Step 2: Activate the rotary positioning mechanism to clamp and limit the fuel rod bundle;

[0145] Step 3: Start the three-dimensional moving mechanism, adjust the X / Y values ​​so that the first underwater measuring camera is positioned directly above the rod bundle measuring calibration plate, and then adjust the Z value so that the image of the first underwater measuring camera covers the entire rod bundle measuring calibration plate.

[0146] Step 4: Start the first underwater measurement camera software system, acquire images of the rod bundle measurement calibration plate and correct the images, and calculate the pixel conversion coefficient to complete the rod bundle measurement calibration;

[0147] Step 5: Activate the rotary positioning mechanism to rotate the fuel rod bundle to the 0-degree position;

[0148] Step 6: Activate the three-dimensional moving mechanism, move the first underwater measurement camera until the center line of the fuel rod bundle is in the center of the camera screen, and then complete the overall segmented photography and acquisition of the fuel rod bundle along the axial direction of the fuel rod bundle;

[0149] Step 7: Start the software system of the first underwater measurement camera to complete the segmented image stitching and edge extraction of the fuel rod bundle;

[0150] Step 8: Operate the software system of the first underwater measurement camera to complete the measurement of the fuel rod bundle length at this angle;

[0151] Step 9: Operate the software system of the first underwater measurement camera to complete the measurement of the fuel rod bundle bending at this angle;

[0152] Step 10: Repeat steps 5 to 9, rotating the fuel rod bundle 90 degrees each time, to complete the length and curvature measurement of the fuel rod bundle at four angles;

[0153] Step 11: Start the three-dimensional moving mechanism, adjust the X / Y values ​​so that the first underwater measuring camera is positioned directly above the component measuring calibration plate, and then adjust the Z value so that the image of the first underwater measuring camera covers the entire component measuring calibration plate.

[0154] Step 12: Start the first underwater measurement camera software system, acquire images of the component measurement calibration board and correct the images, and calculate the pixel conversion coefficients to complete the component measurement calibration;

[0155] Step 13: Activate the three-dimensional moving mechanism, move the first underwater measuring camera until the center line of the fuel element is in the center of the camera screen, and then complete the overall segmented photography and acquisition of the fuel element along the axial direction of the fuel element;

[0156] Step Fourteen: Start the software system of the first underwater measurement camera to complete the segmented image stitching and edge extraction of the fuel element;

[0157] Step 15: Operate the software system of the first underwater measurement camera to complete the fuel element length measurement;

[0158] Step 16: Operate the software system of the first underwater measurement camera to complete the fuel element spacing measurement;

[0159] Step 17: Activate the rotary positioning mechanism to rotate the fuel rod bundle by 20 degrees;

[0160] Step 18: Repeat steps 12 to 17, rotating the fuel rod bundle by 20 degrees each time, to complete the measurement of the length and spacing of the 18 fuel elements on the outer ring of the fuel rod bundle;

[0161] Step 19: Start the rotary positioning mechanism, release the clamping limit, and grab the fuel rod bundle away from the rotary positioning mechanism inspection station.

[0162] Specific Implementation Example (II): Measurement of Rod Bundle End Plates:

[0163] Step 1: Grab the fuel rod bundle and place it on the inspection station of the rotary positioning mechanism;

[0164] Step 2: Activate the rotary positioning mechanism to clamp and limit the fuel rod bundle, then release the limits at both ends;

[0165] Step 3: Activate the three-dimensional moving mechanism and move the first underwater measurement camera to directly above the end plate reflector so that the image of the first underwater measurement camera covers the entire first end plate of the fuel rod bundle;

[0166] Step 4: Start the software system of the first underwater measurement camera to complete the image acquisition and edge extraction of the first end plate of the fuel rod bundle;

[0167] Step 5: Operate the software system of the first underwater measurement camera to complete the visual inspection and diameter measurement of the first end plate of the fuel rod bundle;

[0168] Step 6: Start the underwater motor of the camera motion module to rotate and move the second underwater measuring camera horizontally until the screen covers the entire second end plate of the fuel rod bundle;

[0169] Step 7: Start the second underwater measurement camera software system to complete image acquisition and edge extraction of the second end plate of the fuel rod bundle;

[0170] Step 8: Operate the software system of the second underwater measurement camera to complete the visual inspection and diameter measurement of the second end plate of the fuel rod bundle;

[0171] Step 9: Grab the fuel rod bundle and remove it from the rotary positioning mechanism inspection station.

[0172] In this application, the term "multiple" refers to two or more unless otherwise expressly defined. The terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0173] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0174] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for underwater dimensional measurement of heavy water reactor fuel rod bundles, characterized in that, An underwater dimensional measurement system for heavy water reactor fuel rod bundles is employed. The fuel rod bundle includes multiple fuel elements and first and second end plates located at both ends of the fuel elements. The underwater dimensional measurement system for heavy water reactor fuel rod bundles includes: a support platform; a rotation positioning mechanism disposed on the support platform for clamping and driving the fuel rod bundle to rotate; a three-dimensional movement mechanism disposed on the support platform; a first underwater measurement camera disposed on the three-dimensional movement mechanism and driven by the three-dimensional movement mechanism to move in three-dimensional space for acquiring overall images of the fuel rod bundle and images of individual fuel elements; and a camera measurement calibration platform disposed on the support platform, including a fuel rod bundle measurement calibration plate and an element measurement calibration plate. The upper surface of the fuel rod bundle measurement calibration plate is flush with the centerline of the fuel rod bundle; the upper surface of the element measurement calibration plate is flush with the centerline of the top fuel element of the fuel rod bundle; a first reflector assembly, mounted on the support platform, is used to reflect the image of the first end plate to the first underwater measurement camera; a camera motion module, mounted on the support platform, includes two module guide rails and a camera bracket that can slide along the module guide rails; a second underwater measurement camera, mounted on the camera bracket, is used to acquire the image of the second end plate; a second reflector assembly, mounted on the camera bracket, is used to reflect the image of the second end plate to the second underwater measurement camera; the method includes the following steps: Secure the fuel rod bundle to the underwater rotating position; Drive the first underwater measurement camera to the calibration plate area for camera calibration and obtain pixel conversion coefficients; Rotate the fuel rod bundle to a first angle, drive the first underwater measurement camera to move along the axial direction of the fuel rod bundle, and acquire the overall image of the rod bundle in segments; Based on segmented images, stitching and edge extraction are performed to calculate the length and curvature of the fuel rod bundle at the first angle; Rotate the fuel rod bundle to multiple different angles, drive the first underwater measuring camera to move along the fuel rod bundle axis, acquire the overall image of the rod bundle in segments, perform stitching and edge extraction based on the segmented images, calculate the length and curvature of the fuel rod bundle at multiple different angles, and complete the multi-angle dimension measurement. Drive the first underwater measuring camera to the calibration plate area and recalibrate the calibration plate; For each fuel element on the outer ring of the fuel rod bundle, the fuel rod bundle is rotated sequentially and the first underwater measuring camera is driven to move along the element axis to acquire images of individual fuel elements in segments and calculate the length and spacing of each fuel element; The image of the first endplate of the fuel rod bundle is reflected to the first underwater measuring camera through the first reflector assembly for image acquisition and diameter measurement. The image of the second endplate of the fuel rod bundle is reflected to the second underwater measuring camera via the second reflector assembly for image acquisition and diameter measurement.

2. The underwater dimension measurement method for heavy water reactor fuel rod bundles according to claim 1, characterized in that, The camera motion module also includes: a connecting base plate and a lead screw transmission mechanism; The connecting base plate is disposed on the supporting platform, and the two module guide rails are arranged side by side on both sides of the connecting base plate; The lead screw transmission mechanism includes a lead screw, a lead screw support, an underwater motor, and a lead screw nut. The lead screw support is disposed on the connecting base plate. One end of the lead screw is connected to the underwater motor through a coupling, and the other end of the lead screw is supported by the lead screw support. The lead screw is located between two module guide rails. The lead screw nut is connected to the camera bracket. The camera bracket slides with the module guide rails through a module slider. The camera measurement and calibration platform also includes: The mounting legs are installed on the support platform, and the rod bundle measurement and calibration plate is installed on the mounting legs and fixed by the pressure plate. A support base is provided on the pressure plate, and the component measurement calibration plate is provided on the support base and fixed by a pressure strip. The support base can adjust the height and angle of the component measurement calibration plate.

3. The underwater dimension measurement method for heavy water reactor fuel rod bundles according to claim 1, characterized in that, The first reflector assembly includes: A rearview mirror bracket is mounted on the support platform; The end plate reflector is embedded in the reflector bracket at a preset angle.

4. The underwater dimension measurement method for heavy water reactor fuel rod bundles according to claim 1, characterized in that, The upper surface of the rod bundle measurement calibration plate is provided with a black and white checkered pattern; the upper surface of the component measurement calibration plate is provided with a black and white checkered pattern.

5. The underwater dimension measurement method for heavy water reactor fuel rod bundles according to claim 1, characterized in that, The process of driving the first underwater measurement camera to move to the calibration plate area for camera calibration and obtaining pixel conversion coefficients includes: Drive the first underwater measurement camera to move above the rod bundle measurement calibration plate; Adjust the height of the first underwater measuring camera so that its field of view completely covers the rod bundle measuring calibration plate; The image of the rod bundle measurement calibration plate is acquired, the image is corrected, and the pixel conversion coefficient is calculated to complete the rod bundle measurement calibration.

6. The underwater dimension measurement method for heavy water reactor fuel rod bundles according to claim 1, characterized in that, The step of driving the first underwater measuring camera to move to the calibration plate area and recalibrating the calibration plate includes: Drive the first underwater measurement camera to move above the component measurement calibration plate; Adjust the height of the first underwater measuring camera so that its field of view completely covers the component measurement calibration plate; The image of the component measurement calibration board is acquired, image correction processing is performed, and pixel conversion coefficients are calculated to complete the calibration of the fuel element measurement.

7. The underwater dimension measurement method for heavy water reactor fuel rod bundles according to claim 1, characterized in that, The process of reflecting the image of the first endplate of the fuel rod bundle to the first underwater measuring camera via the first reflector assembly for image acquisition and diameter measurement includes the following steps: Start the rotary positioning mechanism to clamp and limit the fuel rod bundle, and then release the limits at both ends; Activate the three-dimensional moving mechanism to move the first underwater measurement camera to directly above the end plate reflector, so that the image of the first underwater measurement camera covers the entire first end plate of the fuel rod bundle; Start the software system of the first underwater measurement camera to complete the image acquisition and edge extraction of the first endplate of the fuel rod bundle; Operate the software system of the first underwater measurement camera to complete the appearance inspection and diameter measurement of the first end plate of the fuel rod bundle.

8. The underwater dimension measurement method for heavy water reactor fuel rod bundles according to claim 1, characterized in that, The process of reflecting the image of the second endplate of the fuel rod bundle to the second underwater measuring camera via the second reflector assembly for image acquisition and diameter measurement includes the following steps: Drive the second underwater measurement camera to move horizontally so that its field of view covers the second end plate of the fuel rod bundle; Acquire the reflection image of the second end plate and perform edge extraction processing; Based on the extracted edge features, the appearance inspection and diameter measurement of the second end plate are completed.

Images