Nuclear fuel element welding seam automatic detection device

Abstract

The invention specifically relates to a nuclear fuel element welding seam automatic detection device comprising an image acquisition device which is installed on a double-station end plug welding machine and is used for acquiring a nuclear fuel element welding seam image and sending the nuclear fuel element welding seam image to an image processing system; and the image processing system is used for carrying out nuclear fuel element welding seam detection according to the nuclear fuel element welding seam image. According to the automatic detection device for the welding seam of the nuclear fuel element, automatic detection of the appearance, the weld beading size and the concentricity size of the welding seam of the Candi-6 nuclear fuel element after end plug welding is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear fuel element manufacturing, in particular to an automatic detection device for nuclear fuel element welds. Background Art

[0002] In recent years, machine vision inspection has been continuously applied in the field of nuclear fuel element manufacturing. Nuclear fuel element factories have tried to use machine vision to inspect product appearance to ensure product quality in multiple nuclear fuel element production lines such as heavy water reactors, pressurized water reactors, and high-temperature gas-cooled reactors. Due to the inconsistency of production products, visual inspection types and algorithms are also being upgraded and improved to adapt to different products.

[0003] The end plug welding process is a key and important process in the manufacturing process of Candu-6 nuclear fuel elements. The cladding tube and the end plug are welded by a double-station end plug welding machine. The product size and weld appearance inspection after end plug welding is an important means to ensure product quality. At present, the weld appearance and size inspection of products are still in the traditional manual inspection stage. This method has low detection efficiency, high false detection rate, high labor intensity, high manual inspection cost, and is easily affected by workers' experience and subjective factors. It is also unable to detect the shape of the weld bump after the product is welded. Therefore, it is necessary to design a set of nuclear fuel element weld automatic inspection equipment. Summary of the invention

[0004] The object of the present invention is to provide an automatic detection device for nuclear fuel element welds, which can realize automatic detection of the appearance, weld bead size and concentricity size of the Candu-6 nuclear fuel element welds after end plug welding.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A nuclear fuel element weld automatic detection device, comprising:

[0007] Image acquisition equipment, installed on the double-station end plug welding machine, used to collect images of nuclear fuel element welds and send them to the image processing system;

[0008] The image processing system is used to detect the appearance and size defects of the nuclear fuel element welds based on the nuclear fuel element weld images.

[0009] In the present invention, the image acquisition equipment includes a 3D line scan camera, a 2D area array camera and a defect detection lens; the 2D area array camera is matched with the defect detection lens; the 2D area array camera and the defect detection lens are fixed on the working panel of the double-station end plug welding machine through an equipment bracket, at an angle of 45° to the nuclear fuel element, and are used to collect the 2D image of the nuclear fuel element weld; the 3D line scan camera is fixed on the column of the double-station end plug welding machine through a link plate, just above the nuclear fuel element, and is used to collect the 3D image of the nuclear fuel element weld.

[0010] In the present invention, the 3D line scan camera includes a non-reference end 3D line scan camera and a reference end 3D line scan camera which are symmetrically arranged; the 2D area array camera includes a reference end 2D area array camera and a non-reference end 2D area array camera which are symmetrically arranged; the defect detection lens includes a non-reference end defect detection lens and a reference end defect detection lens which are symmetrically arranged; the reference end 2D area array camera matches the reference end defect detection lens, and the non-reference end 2D area array camera matches the non-reference end defect detection lens;

[0011] The reference end 2D area array camera and the reference end defect detection lens are fixed on the working panel of the double-station end plug welding machine through the reference end equipment bracket, at an angle of 45° to the nuclear fuel element, and are used to collect the 2D image of the weld at the reference end of the nuclear fuel element; the non-reference end 2D area array camera and the non-reference end defect detection lens are fixed on the working panel of the double-station end plug welding machine through the non-reference end equipment bracket, at an angle of 45° to the nuclear fuel element, and are used to collect the 2D image of the weld at the non-reference end of the nuclear fuel element;

[0012] The reference end 3D line scan camera is fixed on the double-station end plug welding column through a link plate, just above the nuclear fuel element, and is used to collect the 3D image of the reference end weld of the nuclear fuel element; the non-reference end 3D line scan camera is fixed on the double-station end plug welding column through a link plate, just above the nuclear fuel element, and is used to collect the 3D image of the non-reference end weld of the nuclear fuel element.

[0013] In the present invention, a nuclear fuel element weld inspection station is provided on the double-station end plug welding machine; the nuclear fuel element weld size defect inspection includes the nuclear fuel element weld concentricity size and weld bump size inspection;

[0014] The image processing system detects the concentricity and weld size of nuclear fuel element welds based on the 3D image of nuclear fuel element welds;

[0015] The image acquisition device acquires the 3D image of the nuclear fuel element weld, including the following steps: the nuclear fuel element is moved to the nuclear fuel element weld inspection station through the servo rotating mechanism at the front end of the double-station end plug welding machine; while the servo rotating mechanism drives the nuclear fuel element to rotate continuously for one circle, the 3D line scan camera acquires the 3D image of the nuclear fuel element weld.

[0016] In the present invention, the image processing system detects the concentricity size and weld bump size of the nuclear fuel element weld according to the 3D image of the nuclear fuel element weld, including the following steps:

[0017] For the 3D image of the nuclear fuel element weld, n regions are selected on the end plug cylindrical surface and the rod cylindrical surface respectively, and the n regions on the end plug cylindrical surface and the rod cylindrical surface correspond one to one;

[0018] Read the heights of n regions of the end plug cylinder and the rod body cylinder respectively, and calculate the difference between the heights of two corresponding regions of the end plug cylinder and the rod body cylinder, recorded as D i ;

[0019] Calculate all D i The average value is denoted as M;

[0020] Calculate each D separately i The difference between M and d i ;d i =D i -M;

[0021] Determine each d i Is it greater than the set threshold T? i If it is greater than the set threshold T, the count value N is increased by 1;

[0022] When the count value N is greater than the set threshold value TN, the concentricity eccentricity of the nuclear fuel element is determined, and the information of the maximum position of the concentricity eccentricity of the nuclear fuel element is output;

[0023] i is an integer from 1 to n.

[0024] In the present invention, the image processing system performs appearance inspection of the nuclear fuel element weld according to the 2D image of the nuclear fuel element weld;

[0025] The image acquisition device acquires 2D images of nuclear fuel element welds, including the following steps: the nuclear fuel element is moved to the nuclear fuel element weld inspection station through the servo rotation mechanism at the front end of the double-station end plug welding machine; while the servo rotation mechanism drives the nuclear fuel element to rotate continuously for one circle, the 2D area array camera and the defect detection lens continuously acquire 2D images of the nuclear fuel element welds.

[0026] In the present invention, the image processing system performs appearance inspection of the nuclear fuel element weld according to the 2D image of the nuclear fuel element weld, comprising the following steps:

[0027] Locate the 2D image of the nuclear fuel element weld and obtain the ROI of the target defect;

[0028] According to the ROI of the target defect, the appearance defects of the nuclear fuel element weld are detected.

[0029] In the present invention, the image processing system locates the 2D image of the nuclear fuel element weld and obtains the ROI of the target defect, including the following steps:

[0030] First, the algorithm is used to find the bottom boundary line of the end plug, and then the ROI of the target defects where the arc mark and oxidation are located is obtained by combining the imaging characteristics and the defect location.

[0031] In the present invention, the appearance inspection of the nuclear fuel element weld includes the inspection of the oxidation color and arc mark of the nuclear fuel element weld;

[0032] The image processing system detects oxidation color of nuclear fuel element welds according to the ROI of the target defect, including the following steps:

[0033] The ROI of the target defect is separated by HSV channels, and the H channel is selected for blob analysis. The oxidation color area to be screened is selected by combining the threshold judgment. Finally, the non-oxidation color area is eliminated by area screening. The oxidation color area is obtained and marked in the 2D image of the nuclear fuel element weld.

[0034] The image processing system performs arc mark detection on the weld of nuclear fuel elements according to the ROI of the target defect, including the following steps:

[0035] The RGB channels of the ROI of the target defect are separated, and the R channel is selected for blob analysis. The arc mark area to be screened is selected based on the threshold judgment. Finally, the non-arc mark area is eliminated by area screening. The arc mark area is obtained and marked in the 2D image of the nuclear fuel element weld.

[0036] In the present invention, the nuclear fuel elements for nuclear fuel element weld appearance and size defect detection are all nuclear fuel elements before weld nodules are removed.

[0037] Beneficial technical effects of the present invention:

[0038] The nuclear fuel element weld automatic detection device of the present invention realizes the automatic detection of the nuclear fuel element weld; the concentricity size and the weld nodule size of the nuclear fuel element weld before the weld nodule is removed are automatically detected according to the 3D image of the nuclear fuel element weld, the information of the maximum position of the concentricity eccentricity of the nuclear fuel element before the weld nodule is removed is output, and the weld nodule area is detected by comparing with the surrounding area to determine whether there are defects such as abnormal protrusions and oxidation, thereby ensuring the quality of the weld; the oxidation color and arc marks of the nuclear fuel element weld after the weld nodule is removed are automatically detected according to the 2D image of the nuclear fuel element weld, and defects with tiny changes that are difficult for the naked eye to distinguish are automatically detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The figure is a schematic structural diagram of an embodiment of the nuclear fuel element weld automatic detection device of the present invention.

[0040] In the figure, 1. servo rotation mechanism; 2. 3D line scan camera at non-reference end; 3. 3D line scan camera at reference end; 4. defect detection lens at non-reference end; 5. defect detection lens at reference end; 6. 2D area array camera at reference end; 7. 2D area array camera at non-reference end; 8. equipment bracket at non-reference end; 9. equipment bracket at reference end. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by terms such as “left end”, “right end”, “above”, “below”, “outside”, “inside”, etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0043] See also Figure 1 This embodiment provides a nuclear fuel element weld automatic detection device, comprising:

[0044] Image acquisition equipment, installed on the double-station end plug welding machine, used to collect images of nuclear fuel element welds and send them to the image processing system;

[0045] The image processing system is used to detect the appearance and size defects of the nuclear fuel element welds based on the nuclear fuel element weld images.

[0046] In this embodiment, the image acquisition device includes a 3D line scan camera, a 2D area array camera and a defect detection lens; the 2D area array camera is matched with the defect detection lens; the 2D area array camera and the defect detection lens are fixed on the working panel of the double-station end plug welding machine through an equipment bracket, at a 45° angle to the nuclear fuel element, and are used to collect 2D images of the welds of the nuclear fuel elements; the 3D line scan camera is fixed on the column of the double-station end plug welding machine through a link plate, just above the nuclear fuel element, and is used to collect 3D images of the welds of the nuclear fuel elements.

[0047] The equipment bracket structure is stable and reliable. After installation, it will not be affected by the operating vibration of the double-station end plug welder, thereby improving the detection accuracy of the detection device. The equipment bracket utilizes the existing space of the double-station end plug welder, and after installation and integration, it will not affect the original functional operation, maintenance and overhaul of the double-station end plug welder.

[0048] In this embodiment, the 3D line scan camera includes a non-reference end 3D line scan camera 2 and a reference end 3D line scan camera 3 that are symmetrically arranged; the 2D area array camera includes a reference end 2D area array camera 6 and a non-reference end 2D area array camera 7 that are symmetrically arranged; the defect detection lens includes a non-reference end defect detection lens 4 and a reference end defect detection lens 5 that are symmetrically arranged; the reference end 2D area array camera 6 matches the reference end defect detection lens 5, and the non-reference end 2D area array camera 7 matches the non-reference end defect detection lens 4;

[0049] The reference end 2D area array camera 6 and the reference end defect detection lens 5 are fixed on the working panel of the double-station end plug welding machine through the reference end equipment bracket 9, at an angle of 45° to the nuclear fuel element, and are used to collect the 2D image of the reference end weld of the nuclear fuel element; the non-reference end 2D area array camera 7 and the non-reference end defect detection lens 4 are fixed on the working panel of the double-station end plug welding machine through the non-reference end equipment bracket 8, at an angle of 45° to the nuclear fuel element, and are used to collect the 2D image of the non-reference end weld of the nuclear fuel element;

[0050] The reference end 3D line scan camera 3 is fixed on the double-station end plug welding column through a link plate, just above the nuclear fuel element, and is used to collect the 3D image of the reference end weld of the nuclear fuel element; the non-reference end 3D line scan camera 2 is fixed on the double-station end plug welding column through a link plate, just above the nuclear fuel element, and is used to collect the 3D image of the non-reference end weld of the nuclear fuel element.

[0051] Positional displacement of the nuclear fuel element end plug before or during welding may lead to eccentricity of the nuclear fuel element weld. In this embodiment, a nuclear fuel element weld inspection station is provided on the double-station end plug welding machine; the nuclear fuel element weld size defect inspection includes the nuclear fuel element weld concentricity size and weld bump size inspection;

[0052] The image processing system detects the concentricity and weld size of nuclear fuel element welds based on the 3D image of nuclear fuel element welds;

[0053] The image acquisition device acquires the 3D image of the nuclear fuel element weld, including the following steps: the nuclear fuel element is moved to the nuclear fuel element weld detection station through the servo rotating mechanism 1 at the front end of the double-station end plug welding machine; while the servo rotating mechanism 1 drives the nuclear fuel element to rotate continuously for one circle, the 3D line scan camera acquires the 3D image of the nuclear fuel element weld.

[0054] In this embodiment, the image processing system detects the concentricity and weld size of the nuclear fuel element weld according to the 3D image of the nuclear fuel element weld, including the following steps:

[0055] For the 3D image of the nuclear fuel element weld, n regions are selected on the end plug cylindrical surface and the rod cylindrical surface respectively, and the n regions on the end plug cylindrical surface and the rod cylindrical surface correspond one to one;

[0056] Read the heights of n regions of the end plug cylinder and the rod body cylinder respectively, and calculate the difference between the heights of two corresponding regions of the end plug cylinder and the rod body cylinder, recorded as D i ;

[0057] Calculate all D i The average value is denoted as M;

[0058] Calculate each D separately iThe difference between M and d i ;d i =D i -M;

[0059] Determine each d i Is it greater than the set threshold T? i If it is greater than the set threshold T, the count value N is increased by 1;

[0060] When the count value N is greater than the set threshold value TN, the concentricity eccentricity of the nuclear fuel element is determined, and the information of the maximum position of the concentricity eccentricity of the nuclear fuel element is output;

[0061] i is an integer from 1 to n.

[0062] In this embodiment, for the detection of nuclear fuel element size defects, the nuclear fuel element weld 3D image is a 16-bit Tif image.

[0063] In this embodiment, the image processing system performs appearance inspection of the nuclear fuel element weld according to the 2D image of the nuclear fuel element weld;

[0064] The image acquisition device acquires 2D images of nuclear fuel element welds, including the following steps: the nuclear fuel element is moved to the nuclear fuel element weld detection station through the servo rotation mechanism 1 at the front end of the double-station end plug welding machine; while the servo rotation mechanism 1 drives the nuclear fuel element to rotate continuously for one circle, the 2D area array camera and the defect detection lens continuously acquire 2D images of the nuclear fuel element welds.

[0065] In this embodiment, the image processing system performs appearance inspection of the nuclear fuel element weld according to the 2D image of the nuclear fuel element weld, including the following steps:

[0066] Locate the 2D image of the nuclear fuel element weld and obtain the ROI of the target defect;

[0067] According to the ROI of the target defect, the appearance defects of the nuclear fuel element weld are detected.

[0068] The 2D images of nuclear fuel element welds collected by the 2D array camera and defect detection lens completely cover the nuclear fuel element welds, making it convenient for the subsequent image processing system to perform appearance inspection of nuclear fuel element welds. In order to determine the detection range of appearance defects in nuclear fuel element welds, the image processing system locates the target area of ​​appearance defects in nuclear fuel element welds based on imaging characteristics.

[0069] In this embodiment, the image processing system locates the 2D image of the nuclear fuel element weld to obtain the ROI of the target defect, including the following steps:

[0070] First, the algorithm is used to find the bottom boundary line of the end plug, and then the areas where the arc mark and oxidation are located are obtained by combining the imaging characteristics and the defect location to obtain the ROI of the target defect.

[0071] In this embodiment, the appearance inspection of the nuclear fuel element weld includes the inspection of the oxidation color and arc mark of the nuclear fuel element weld;

[0072] The image processing system detects oxidation color of nuclear fuel element welds according to the ROI of the target defect, including the following steps:

[0073] The ROI of the target defect is separated by HSV channels, and the H channel is selected for blob analysis. The oxidation color area to be screened is selected by combining the threshold judgment. Finally, the non-oxidation color area is eliminated by area screening. The oxidation color area is obtained and marked in the 2D image of the nuclear fuel element weld.

[0074] The image processing system performs arc mark detection on the weld of nuclear fuel elements according to the ROI of the target defect, including the following steps:

[0075] The RGB channels of the ROI of the target defect are separated, and the R channel is selected for blob analysis. The arc mark area to be screened is selected based on the threshold judgment. Finally, the non-arc mark area is eliminated by area screening. The arc mark area is obtained and marked in the 2D image of the nuclear fuel element weld.

[0076] In this embodiment, the nuclear fuel elements for nuclear fuel element weld appearance and size defect inspection are all nuclear fuel elements before weld nodules are removed.

[0077] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A nuclear fuel element weld automatic detection device, characterized in that: include: Image acquisition equipment, installed on the double-station end plug welding machine, used to collect images of nuclear fuel element welds and send them to the image processing system; The image processing system is used to detect the welds of nuclear fuel elements based on the weld images of nuclear fuel elements.

2. The nuclear fuel element weld automatic detection device according to claim 1, characterized in that: The image acquisition equipment includes a 3D line scan camera, a 2D area array camera and a defect detection lens; the 2D area array camera is matched with the defect detection lens; the 2D area array camera and the defect detection lens are fixed on the working panel of the double-station end plug welding machine through an equipment bracket, at an angle of 45° to the nuclear fuel element, and are used to collect 2D images of the welds of the nuclear fuel elements; the 3D line scan camera is fixed on the column of the double-station end plug welding machine through a link plate, just above the nuclear fuel element, and is used to collect 3D images of the welds of the nuclear fuel elements.

3. The nuclear fuel element weld automatic detection device according to claim 2, characterized in that: The 3D line scan camera comprises a non-reference end 3D line scan camera (2) and a reference end 3D line scan camera (3) which are symmetrically arranged; the 2D area array camera comprises a reference end 2D area array camera (6) and a non-reference end 2D area array camera (7) which are symmetrically arranged; the defect detection lens comprises a non-reference end defect detection lens (4) and a reference end defect detection lens (5) which are symmetrically arranged; the reference end 2D area array camera (6) matches the reference end defect detection lens (5), and the non-reference end 2D area array camera (7) matches the non-reference end defect detection lens (4); The reference end 2D array camera (6) and the reference end defect detection lens (5) are fixed on the working panel of the double-station end plug welding machine through the reference end equipment bracket (9), at an angle of 45° to the nuclear fuel element, and are used to collect the 2D image of the weld seam at the reference end of the nuclear fuel element; The non-reference end 2D area array camera (7) and the non-reference end defect detection lens (4) are fixed on the working panel of the double-station end plug welding machine through the non-reference end equipment bracket (8), at an angle of 45° to the nuclear fuel element, and are used to collect the 2D image of the weld seam of the non-reference end of the nuclear fuel element; The reference end 3D line scan camera (3) is fixed on the double-station end plug welding column through a link plate, just above the nuclear fuel element, and is used to collect the 3D image of the reference end weld of the nuclear fuel element; the non-reference end 3D line scan camera (2) is fixed on the double-station end plug welding column through a link plate, just above the nuclear fuel element, and is used to collect the 3D image of the non-reference end weld of the nuclear fuel element.

4. The nuclear fuel element weld automatic detection device according to claim 2, characterized in that: The double-station end plug welding machine is equipped with a nuclear fuel element weld inspection station; the nuclear fuel element weld inspection includes the nuclear fuel element weld concentricity size and weld bump size inspection; The image processing system detects the concentricity and weld size of nuclear fuel element welds based on the 3D image of nuclear fuel element welds; The image acquisition device acquires a 3D image of a nuclear fuel element weld, comprising the following steps: the nuclear fuel element is moved to a nuclear fuel element weld detection station via a servo rotating mechanism (1) at the front end of a double-station end plug welding machine; while the servo rotating mechanism (1) drives the nuclear fuel element to continuously rotate one circle, a 3D line scan camera acquires a 3D image of the nuclear fuel element weld.

5. The nuclear fuel element weld automatic detection device according to claim 4, characterized in that: The image processing system detects the concentricity and weld size of the nuclear fuel element weld according to the 3D image of the nuclear fuel element weld, including the following steps: For the 3D image of the nuclear fuel element weld, n regions are selected on the end plug cylindrical surface and the rod cylindrical surface respectively, and the n regions on the end plug cylindrical surface and the rod cylindrical surface correspond one to one; Read the heights of n regions of the end plug cylinder and the rod body cylinder respectively, and calculate the difference between the heights of two corresponding regions of the end plug cylinder and the rod body cylinder, recorded as D i ; Calculate all D i The average value is denoted as M; Calculate each D separately i The difference between M and d i ;d i =D i -M; Determine each d i Is it greater than the set threshold T? i If it is greater than the set threshold T, the count value N is increased by 1; When the count value N is greater than the set threshold value TN, the concentricity eccentricity of the nuclear fuel element is determined, and the information of the maximum position of the concentricity eccentricity of the nuclear fuel element is output; i is an integer from 1 to n.

6. The nuclear fuel element weld automatic detection device according to claim 4, characterized in that: Nuclear fuel element weld inspection also includes nuclear fuel element weld appearance inspection; The image processing system performs appearance inspection of the nuclear fuel element welds based on the 2D images of the nuclear fuel element welds; The image acquisition device acquires 2D images of nuclear fuel element welds, comprising the following steps: the nuclear fuel element is moved to a nuclear fuel element weld detection station via a servo rotating mechanism (1) at the front end of a double-station end plug welding machine; while the servo rotating mechanism (1) drives the nuclear fuel element to continuously rotate one circle, a 2D area array camera and a defect detection lens continuously acquire 2D images of the nuclear fuel element welds.

7. The nuclear fuel element weld automatic detection device according to claim 6, characterized in that: The image processing system performs appearance inspection of the nuclear fuel element weld according to the 2D image of the nuclear fuel element weld, including the following steps: Position the 2D image of the nuclear fuel element weld and obtain ROI; According to ROI, the appearance of the nuclear fuel element weld is inspected.

8. The nuclear fuel element weld automatic detection device according to claim 7, characterized in that: The image processing system locates the 2D image of the nuclear fuel element weld and obtains the ROI, including the following steps: First, find the bottom boundary line of the end plug, and then combine the imaging characteristics to obtain the areas where the arc mark and oxidation are located to obtain the ROI.

9. The nuclear fuel element weld automatic detection device according to claim 8, characterized in that: Nuclear fuel element weld appearance inspection includes oxidation color and arc mark inspection of nuclear fuel element welds; The image processing system detects oxidation color of the nuclear fuel element weld according to the ROI, including the following steps: HSV channel separation of the ROI, selecting the H channel for blob analysis, selecting the oxidation color screening area in combination with the threshold, and finally eliminating the non-oxidation color area by area screening, obtaining the oxidation color area and marking it in the 2D image of the nuclear fuel element weld; The image processing system performs arc mark detection on the weld of nuclear fuel elements according to ROI, including the following steps: The ROI is separated into RGB channels, and the R channel is selected for blob analysis. The arc mark area to be screened is selected based on the threshold judgment. Finally, the non-arc mark area is eliminated by area screening. The arc mark area is obtained and marked in the 2D image of the nuclear fuel element weld.

10. The nuclear fuel element weld automatic detection device according to claim 6, characterized in that: The nuclear fuel elements subjected to weld appearance inspection are the nuclear fuel elements after the weld nodules are removed; the nuclear fuel elements subjected to weld concentricity size and weld nodule size inspection are the nuclear fuel elements before the weld nodules are removed.

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