Method of pipeline weld radiographic testing

Abstract

A method for radiographic inspection of pipe welds is provided. Markings are made on the source guide tube to ensure that the depth of insertion into the pipe allows the radiation emitted by the radiographic unit to reach the weld. Outside the pipe, the source guide tube passes through a central support rod, a front-end positioning support structure, and a rear-end positioning support structure, with one or more supports of the front-end and rear-end positioning support structures separated from the annular component. The radiographic unit, the front-end positioning support structure, the central rod, and the rear-end positioning support structure sequentially pass through an elbow opening, and all supports are mounted on the annular component after the front-end and rear-end positioning support structures have passed through the elbow opening. The source guide tube continues to extend into the pipe, stopping when the insertion length at the elbow opening reaches the marked point. The radiographic source assembly is then used to begin inspecting the weld inside the pipe. This method enables rapid positioning and accurate detection of the radiographic source at the center of the penetrating component.

Description

Technical Field

[0001] This invention relates to the field of weld inspection, and more specifically to the field of radiographic inspection methods. Background Technology

[0002] The sump penetrating component is one of the important components of the nuclear island. It is connected to the valve and bellows expansion joint assembly on both sides, with a total of 4 welds. Non-destructive testing methods are required to perform radiographic monitoring on the welds to determine the welding quality.

[0003] Chinese patent CN115389536A discloses a radiographic testing center exposure device, including a main structure and an adjustment device and a clamping device on the main structure. The main structure includes a hollow rod-shaped fixed support and a central rotating shaft disposed at the center of the fixed support. The central rotating shaft can extend and retract within the fixed support, and a clamping device is provided at the end of the central rotating shaft. The adjustment device includes a front-end adjustable support and a rear-end adjustable support, with three front and rear-end adjustable supports evenly arranged along the circumference of the fixed support, which can solve the problems of X-ray focusing and centering.

[0004] However, the inventors found that in practice, the device was difficult to place in connected pipes with bends. Summary of the Invention

[0005] One objective of this invention is to provide a method for radiographic inspection of pipe welds, which can perform radiographic inspection of welds in connected pipes in a simple, efficient, and accurate manner.

[0006] To achieve the above objectives, a method for radiographic inspection of pipe welds is provided, which uses a radiographic inspection center exposure positioning device and a radioactive source assembly to inspect welds inside a pipe. The pipe includes an elbow opening. The radioactive source assembly includes a source conduit and a radioactive body, with the radioactive body disposed at the end of the source conduit. The radiographic inspection center exposure positioning device includes: a central support rod, which is a hollow structure, including a front end and a rear end; a front end positioning support structure and a rear end positioning support structure, detachably disposed at the front end and the rear end, respectively, including an annular component and multiple supports distributed circumferentially along the annular component. The annular component is used to fit onto the central support rod, and the supports are used to abut against the inner wall of the pipe. The method includes the following steps: marking the source conduit to a depth that allows the source conduit to penetrate the pipe to a certain extent. The radiation emitted by the radiation source is directed to the weld. Outside the pipe, the source conduit is passed through the central support rod, the front-end positioning support structure, and the rear-end positioning support structure, and one or more supports of the front-end and rear-end positioning support structures are separated from the annular component. The radiation source, the front-end positioning support structure, the central rod, and the rear-end positioning support structure are sequentially passed through the elbow opening, and all supports are installed on the annular component after the front-end and rear-end positioning support structures have passed through the elbow opening. The source conduit is then inserted into the pipe until the insertion length is observed to reach the marked point at the elbow opening. The radiation source assembly is then used to begin inspecting the weld inside the pipe.

[0007] In one or more embodiments, the annular component of the front-end positioning support structure and / or the rear-end positioning support structure is threadedly engaged with the central support rod.

[0008] In one or more embodiments, a camera system is inserted into the pipe, and the images of the inside of the pipe transmitted by the camera system are used to help determine the position of the source conduit or the X-ray detection center exposure positioning device.

[0009] In one or more embodiments, the central support rod is fixed to the source conduit after the source conduit passes through it.

[0010] In one or more embodiments, the distance from the mark to the rear end of the central support rod is equal to the axial distance from the rear end of the central support rod to the elbow opening.

[0011] In one or more embodiments, the bracket is a telescopic support rod.

[0012] In one or more embodiments, the opening direction of the elbow opening is 90° to the axial direction of the pipe.

[0013] In one or more embodiments, the conduit is a pit penetrating component.

[0014] In one or more embodiments, the length of the mark to the radiation body is the axial distance from the weld to the elbow opening.

[0015] In one or more embodiments, the elbow opening is an elbow pipe or a valve.

[0016] The aforementioned radiographic inspection method for pipe welds employs a split-type design for the radiographic inspection center exposure positioning device. This facilitates insertion into elbow openings and, after assembly inside the pipe, effectively supports the radiation source assembly. The weld location is determined using markings on the source guide tube, enabling rapid and accurate detection of the radiation source's center position within the penetration section. This method is also applicable to pipes of various diameters, effectively improving the efficiency of radiographic inspection work. Attached Figure Description

[0017] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram showing the installation location of the pit penetration component; Figure 2 This is a schematic diagram of a double-walled radiographic method for penetrating a component; Figure 3 This is a schematic diagram of the installation method of the exposure positioning device in the X-ray inspection center for the through-hole component in the pit; Figure 4 This is a schematic diagram of the exposure positioning device in the X-ray inspection center; Figure 5 This is a left view of the exposure positioning device in the X-ray inspection center; Figure 6 This is a schematic diagram of the front-end positioning support structure; Figure 7 This is a flowchart of the radiographic inspection method for pipe welds. Detailed Implementation

[0018] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0019] It should be noted that these and other accompanying drawings are merely examples and are not drawn to scale, and should not be construed as limiting the scope of protection of the present invention.

[0020] Current nuclear power technologies mostly employ a double containment structure to enhance nuclear power safety. The mechanical penetrations of the double containment are crucial equipment connecting the internal and external process piping of the reactor, ensuring that pipes, cables, ventilation ducts, entrances, and exits pass through the sealed shield, i.e., the containment, maintaining the integrity of the sealing barrier.

[0021] Penetration components include standard penetration components, high-energy penetration components, sump penetration components, ventilation penetration components, and spare penetration components. Among them, the safety injection system and the safety spray system pass through the containment vessel via the sump penetration component in the nuclear island pool to ensure the circulation of core cooling water.

[0022] like Figure 1 As shown, the starting point of the sump penetration 4 inside the containment is the internal refueling tank, and it is connected to the valve and bellows expansion joint assembly on both sides. To determine the quality of the sump penetration, the design documents stipulate that all welds of the sump penetration must undergo non-destructive testing, requiring 100% radiographic testing. The test results are an important basis for analyzing and evaluating the welding quality of the penetration.

[0023] However, when inspecting each weld after welding is completed, the process piping is already connected, and valves or bends are already installed. If the opening direction of the valve or bend is not aligned with the axial direction of the piping, it is difficult to access the piping for inspection. Figure 1 The 90° bend shown.

[0024] For this structure, traditional X-ray inspection methods generally employ a double-wall irradiation approach, such as... Figure 2 As shown. However, since the internal process pipe 7 has been connected, the X-ray from the radiation source 5 needs to penetrate two walls of the process pipe when it reaches the cassette system 6. The X-rays are filtered when passing through the thicker walls, which hardens the X-rays reaching the detection area and reduces the sensitivity of the film. At the same time, the X-rays need to penetrate thicker materials, which not only requires higher energy to ensure that the X-rays can penetrate four walls, but also requires consideration of X-ray scattering and attenuation. Operators need to control the X-ray parameters, such as voltage, current and exposure time, more carefully, which excessively prolongs the detection time.

[0025] To perform X-ray inspection using center exposure, the angle valve needs to be opened, and the device must be inserted into the pipe through a bend at a 90-degree angle or other angles to locate and detect the weld. This process is not only limited by the insertion port being at an angle to the pipe axis, but also requires accurate centering of the weld inside the pipe, making it quite challenging to implement.

[0026] Based on this, this disclosure proposes a method for radiographic inspection of pipeline welds, which involves installing a radiographic inspection center exposure positioning device and a radioactive source assembly inside the pipeline to perform weld inspection.

[0027] Pipeline 100 includes elbow opening 200, which is a valve or elbow pipe. The opening direction of elbow opening 200 can be perpendicular to the axis of pipeline 100, or it can be 60°, 120°, etc.

[0028] The radioactive source assembly 30 includes, but is not limited to, the use of a gamma ray flaw detector.

[0029] The radioactive source assembly 30 includes a source conduit 31 and a radioactive body 32. The radioactive body 32 is located at the end of the source conduit 31 and includes components such as a shield and a source core encapsulation body. During flaw detection, the radioactive source is pushed to the exposure window position of the radioactive body. There is no leakage of radiation in other directions, only an extremely narrow beam of radiation in the transmission direction, which is used to irradiate the weld being inspected. After flaw detection is completed, the radioactive source is pushed back to the safe position from the window.

[0030] The inside of the source conduit forms a guide channel for the reciprocating motion of the source braid and the radiation source, so as to ensure that the movement path of the radiation source is controlled, the positioning is accurate and the jamming is avoided.

[0031] The X-ray inspection center's exposure positioning device includes a central support rod 11, a front-end positioning support structure 12, and a rear-end positioning support structure 13, all separated from each other. The central support rod 11 is a hollow structure, comprising a front end 1 and a rear end 2. A threaded structure 115 for fixing the source conduit is provided in the middle of the central support rod 11. The threaded structure 115 includes a flat-head bolt knob, which can be engaged with a pre-drilled hole on the side of the support rod to position and press the source conduit 31, thereby fixing the relative position of the central support rod 11 and the source conduit 31.

[0032] The inner diameter of the central support rod 11 is slightly larger than that of the source conduit 31 to ensure that the source conduit 31 can be smoothly inserted.

[0033] The front positioning support structure 12 and the rear positioning support structure 13 are detachably installed at the front end 1 and rear end 2 of the central support rod 11, respectively. Figure 6 As shown, the front-end positioning support structure 12 includes an annular component 120 and three supports 121 distributed circumferentially along the annular component. The annular component 120 is used to be sleeved on the central support rod 11, and the supports 121 are used to abut against the inner wall of the pipe. Figure 5 As shown. In some embodiments, the rear end 2 is provided with an external thread, and the annular member 120 is provided with an internal thread, so that the front end positioning support structure 12 is fixed to the rear end 2 by the threaded engagement. In other embodiments, the annular member 120 can also be fixed to the second end of the central support rod 11 by a snap-fit ​​mechanism.

[0034] Preferably, the bracket 121 is a telescopic support rod, which adjusts the position of the radiation source at the center of the process pipeline through radial telescopic action. One end of the bracket 121 is fixedly connected to the annular member 120 by means such as welding.

[0035] The structure of the back-end positioning support structure 13 is the same as that of the front-end positioning support structure 12.

[0036] This method involves installing the split-type X-ray inspection center exposure positioning device in stages. The final installation of the exposure positioning device is completed inside the through-hole pipe, and then the center positioning is performed.

[0037] Reference Figure 3 The method, as understood, includes the following steps.

[0038] First, a mark is made on the source conduit 31 so that the depth to which the source conduit extends into the pipe allows the rays emitted by the radiation body 32 to reach the weld 110.

[0039] Outside the pipe, the source conduit 31 is passed through the central support rod 11, the front positioning support structure 12, and the rear positioning support structure 13, and one or more supports 121 of the front positioning support structure 12 and the rear positioning support structure 13 are separated from the annular part 120 to facilitate passage through the bend opening 200 of the pipe.

[0040] After the central support rod 11 passes through the source conduit 31, it can be positioned and pressed by the threaded structure 115 to fix the relative position of the source conduit 31 and the X-ray inspection center exposure positioning device.

[0041] The radiation unit, front positioning support structure, central rod, and rear positioning support structure are sequentially passed through the elbow opening 200. After the front and rear positioning support structures have passed through the elbow opening, one or more separate brackets are reinstalled on the annular component to form a triangular support structure. Workers can operate the installation at the elbow opening 200.

[0042] Continue to extend the source conduit 31 into the inside of the pipe 100, and the X-ray inspection center exposure positioning device follows into the pipe, with the support ends of the front positioning support structure and the rear positioning support structure abutting against the inner wall of the pipe.

[0043] The staff observed at the elbow opening 200 that the insertion length of the source conduit 31 reached mark A and then stopped.

[0044] The marker can be set such that the distance from the marker to the rear end of the central support rod is equal to the axial distance from the rear end of the central support rod to the elbow opening. Alternatively, the marker can be set such that the length from the marker to the radiation source is the axial distance from the weld to the elbow opening.

[0045] When the markings on the source conduit 31 are visible at the elbow opening 200, the insertion into the source conduit 31 is stopped. Then, the radiation source assembly is used to inspect the welds inside the pipe.

[0046] At this time, mark A roughly positions the radiation body 32 at the front end of the X-ray inspection center exposure positioning device sent into the pipeline 100 at the location of the weld 110, that is, the distance between mark A and radiation body 32 is roughly equal to the distance L between weld 110 and elbow opening 200.

[0047] In some embodiments, the location of the marker A is further corrected by values ​​such as the distance between the source conduit 31 and the radiation source, and the curvature of the source conduit 31.

[0048] The above method uses a modular structure for the X-ray inspection center's exposure positioning device. This ensures that the device can be easily disassembled and inserted into the pipeline through an angled opening. It can then be easily assembled and used. Through the combination of markings on the source conduit, the front-end positioning support structure, and the rear-end positioning support structure, rapid positioning and stable positioning of the radiation device within the pipeline are achieved. This simplified operation reduces the technical requirements for operators; they only need to place the X-ray source at the center of the object being inspected and adjust the exposure parameters to begin inspection, thus improving work efficiency.

[0049] Preferably, during the entire installation process, the camera system is inserted into the pipeline, and the images of the pipeline interior transmitted by the camera system are used to assist in determining the position of the source conduit, the radiation body, or the exposure positioning device of the X-ray detection center. For example, an industrial pipeline endoscope is used, utilizing optical principles to transmit images to the observation end through a fiber optic bundle, allowing the inspection personnel to directly observe the situation inside the pipeline. For example, it is ensured that the elastic rod, source conduit, and central support rod are coaxial with the pipeline.

[0050] Furthermore, with the aid of transmitted images of the pipe's interior and the contact between the circumferentially distributed telescopic supports and the pipe's inner wall, the source conduit 31 and the central support rod 11 are aligned with the pipe 100, thus achieving the central positioning of the detection source. Figure 3 As shown.

[0051] By utilizing the expandable feature of the support, this method can be applied to pipes of various diameters.

[0052] The above method is particularly suitable for nuclear power plant sump penetrations with angle valves. It involves entering the pipe through the angle valve in a split manner, assembling it internally, and then performing flaw detection. The pipe can be a nuclear power plant sump penetration or any other closed pipe structure with valves. This method is effective in detecting minute defects such as welds, cracks, and porosity, helping to improve the accuracy and reliability of the inspection.

[0053] It should be noted that the use of terms such as "first" and "second" to define the components in the above content is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application.

[0054] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0055] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0056] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for radiographic inspection of pipe welds, characterized in that, Used for inspecting welds inside pipes using X-ray inspection center exposure positioning devices and radiation source assemblies. The pipe includes elbow openings. The radiation source assembly includes a source conduit and a radiation body. The radiation apparatus is disposed at the end of the source conduit, and the radiation detection center exposure positioning device includes: The central support rod is a hollow structure, consisting of a front end and a rear end; The front-end positioning support structure and the rear-end positioning support structure are detachably installed at the front end and the rear end, respectively, and include an annular component and a plurality of supports distributed circumferentially along the annular component. The annular component is used to be sleeved on the central support rod, and the supports are used to abut against the inner wall of the pipe. The method includes the following steps: Mark the source conduit so that the source conduit extends into the pipe to a depth that allows the rays emitted by the radiation body to reach the weld. Outside the pipeline, the source conduit passes through the central support rod, the front-end positioning support structure, and the rear-end positioning support structure, and one or more supports of the front-end positioning support structure and the rear-end positioning support structure are separated from the annular component; The radiation body, the front positioning support structure, the central rod, and the rear positioning support structure are sequentially passed through the elbow opening, and after the front positioning support structure and the rear positioning support structure have passed through the elbow opening, all the supports are installed on the annular component. Continue to extend the source conduit into the pipe, and stop when the insertion length of the source conduit reaches the mark observed at the bend opening; Using a radioactive source assembly to inspect welds inside pipes.

2. The method as described in claim 1, characterized in that, The annular component of the front-end positioning support structure and / or the rear-end positioning support structure is threadedly engaged with the central support rod.

3. The method as described in claim 1, characterized in that, The camera system is inserted into the pipe, and the images of the inside of the pipe transmitted by the camera system are used to help determine the position of the source conduit or the exposure positioning device of the X-ray detection center.

4. The method as described in claim 1, characterized in that, After the source conduit passes through the central support rod, the central support rod is fixed to the source conduit.

5. The method as described in claim 4, characterized in that, The distance from the mark to the rear end of the central support rod is equal to the axial distance from the rear end of the central support rod to the elbow opening.

6. The method as described in claim 1, characterized in that, The bracket is a telescopic support rod.

7. The method as described in claim 1, characterized in that, The opening direction of the elbow is 90° to the axial direction of the pipe.

8. The method as described in claim 1, characterized in that, The pipe is a pit-penetrating component.

9. The method as described in claim 1, characterized in that, The length from the mark to the radiation body is the axial distance from the weld to the elbow opening.

10. The method as described in claim 1, characterized in that, The elbow opening is either an elbow pipe or a valve.

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