Source positioning device for radiographic inspection of reactor main coolant pump impeller blades

Abstract

The present invention provides a source positioning device for radiographic inspection of impeller blades of a reactor main coolant pump, comprising a clamping device and a central conduit, wherein an annular upper slide rail is provided above the clamping device, a slidable slider assembly is provided on the upper slide rail, the central conduit is passed through the center of the clamping device, and the height of the central conduit can be adjusted to locate the position of the radiation source. The source positioning device for radiographic inspection of impeller blades of a reactor main coolant pump provided by the present invention improves the accuracy of radiation source positioning and reduces the irradiation dose.

Description

Technical Field

[0001] The invention relates to the technical field of radiation inspection, and in particular to a source positioning device for radiation inspection of impeller blades of a reactor main coolant pump. Background Art

[0002] The reactor main coolant pump is the core equipment of the primary circuit of a nuclear power plant, and its normal operation plays a vital role in nuclear safety. The impeller of the reactor main coolant pump is the core component of the reactor main coolant pump to promote the water circulation of the primary circuit. It works in a high temperature, high pressure, and high-speed fluid impact environment for a long time. Every overhaul of a nuclear power plant requires the inspection of some reactor main coolant pump impellers.

[0003] The inspected welds of the reactor main coolant pump impeller blades are welded by butt welding and are located in the middle of each blade. The weld shape is a gradually outward-fading arc. Each impeller consists of 6 blades, and the blades overlap each other in the center projection direction.

[0004] In order to ensure the quality of this weld, it is necessary to perform radiographic inspection on it. When implementing this, the radioactive source should be placed at the center of the impeller for panoramic exposure to complete the inspection of the weld near the center of the impeller; then the radioactive source should be placed outside the impeller and the remaining parts of the weld should be inspected one by one using the single-wall exposure method to achieve the overall inspection of the weld.

[0005] During the in-service inspection, the radiation dose of the reactor main coolant pump impeller was as high as several hundred microsieverts. The conventional inspection method, using metal rods and small brackets to fix the radiation source, was time-consuming, not only with a high overall radiation dose, but also inaccurate positioning. As a result, the weld image was easily distorted, and defects were difficult to identify. Repeated tests were often required to obtain the ideal film quality. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects described in the prior art, thereby providing a source positioning device for radiographic inspection of reactor main coolant pump impeller blades, which improves the accuracy of radiation source positioning and reduces the irradiation dose.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A source positioning device for radiographic inspection of impeller blades of a reactor main coolant pump comprises a clamping device and a central conduit. An annular upper slide rail is provided above the clamping device, a slidable slider assembly is provided on the upper slide rail, the central conduit passes through the center of the clamping device, and the height of the central conduit can be adjusted to locate the position of the radiation source.

[0009] As an practicable manner, the slider assembly includes a column, a guide tube and a base, the column is arranged on the base in a height-adjustable manner, and the guide tube is rotatably and telescopically arranged on the column.

[0010] As an practicable manner, the clamping device is an annular structure in which two semicircular frames are connected by a quick clamp.

[0011] As an implementable manner, a positioning block is provided on the inner side of the clamping device.

[0012] As an implementable manner, the bottom of the central conduit is connected to the clamping device via a lower connecting strip.

[0013] As an implementable manner, the lower connecting strip is a rib plate structure.

[0014] As an implementable manner, the upper slide rail is fixedly connected to the clamping device via a support ear.

[0015] As an implementable manner, the clamping device is provided with an adjustment block, and the adjustment block is installed at the connection between the support ear and the clamping device.

[0016] As an implementable manner, the upper surface of the upper slide rail is provided with scale values.

[0017] As an implementable manner, the clamping device, the central conduit and the upper slide rail are coaxially arranged.

[0018] Compared with the prior art, the source positioning device for the radiographic inspection of the impeller blades of the reactor main coolant pump provided by the present invention has the following beneficial effects:

[0019] The source positioning device for the radiation inspection of the impeller blades of the reactor main coolant pump provided by the present invention comprises a clamping device and a central conduit, wherein an annular upper slide rail is arranged above the clamping device, and a slidable slider assembly is arranged on the upper slide rail, and the radiation source positioning work of each blade is realized by the slider assembly, and so on, until all the inspection work is completed. Through this method, the accuracy of the radiation source positioning is increased, the workload of the radiation source positioning is reduced, the consistent exposure conditions are ensured, the difficulty of film washing is reduced, and the one-time success rate of the film is increased. In addition, the central conduit is penetrated at the center of the clamping device, and the height of the central conduit is adjustable to locate the radiation source position, and the source conduit equipped with the radiation source is inserted into the central conduit, and the focal length is adjusted by adjusting the height of the central conduit, thereby reducing the difficulty of focusing of the panoramic exposure, and improving the accuracy of focusing through precise center positioning, reducing the blackness difference and the difficulty of film washing, and increasing the one-time success rate of the film.

[0020] Furthermore, the column on the slider adopts a cylindrical design, which allows the catheter to be adjusted up and down along the column and rotated around the column, so that the position of the radiation source can be adjusted in all directions to accommodate reactor main coolant pump impeller blades of different specifications.

[0021] Furthermore, the overall design of the positioning device is two semicircular structures, which are connected by quick clamps, making installation convenient and quick.

[0022] Furthermore, the upper slide rail adopts a ring-shaped design and has scales engraved on the upper surface, which ensures the repeatability and accuracy of positioning.

[0023] Furthermore, the lower connecting strip is designed with a rib plate, which enhances the structural stability and ensures the accuracy of positioning the radiation source during center exposure.

[0024] Furthermore, the upper slide rail, the clamping device and the central guide tube are coaxially designed to ensure the accuracy of the spatial positioning of the radiation source and the inspected weld. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A front view of a source positioning device for radiographic inspection of reactor main coolant pump impeller blades provided by an embodiment of the present invention;

[0027] Figure 2 A top view of a source positioning device for radiographic inspection of reactor main coolant pump impeller blades provided by an embodiment of the present invention;

[0028] Figure 3 A top view of an adjustment block provided by an embodiment of the present invention;

[0029] Figure 4 A cross-sectional view of an adjustment block provided by an embodiment of the present invention;

[0030] Figure 5 A front view of a slider assembly provided by an embodiment of the present invention;

[0031] Figure 6 A top view of a slider assembly provided in an embodiment of the present invention.

[0032] Description of reference numerals:

[0033] 1. Clamping device; 2. Positioning block; 3. Adjustment block; 4. Center guide tube; 5. Lower connecting strip; 6. Support ear; 7. Upper slide rail; 8. Slider assembly; 9. Column; 10. Guide tube; 11. Base. DETAILED DESCRIPTION

[0034] Although the source positioning device for radiographic inspection of the impeller blades of the reactor main coolant pump of the present invention can be implemented in a variety of different ways, the exemplary embodiments will be described in detail herein in conjunction with the accompanying drawings. It is understood that the description herein should be considered as an example of the structure of the source positioning device for radiographic inspection of the impeller blades of the reactor main coolant pump, and is not intended to limit the protection scope of the present invention to the exemplary embodiments. Therefore, in essence, the drawings and the description of the specific embodiments should be considered to be used to illustrate rather than limit the present invention.

[0035] In the description of the present invention, it should be noted that the terms "up", "down", "left", "right", "inside", "outside", "horizontal", "vertical", etc. used in this document to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0036] The following is further explained in detail through specific implementation methods.

[0037] like Figures 1 to 4 As shown, the present invention provides a source positioning device for the radiographic inspection of the impeller blades of the reactor main coolant pump, which is composed of a positioning assembly, an upper assembly and a lower assembly. The positioning assembly includes a clamping device 1, a positioning block 2 and an adjusting block 3; the lower assembly includes a central guide tube 4 and a lower connecting bar 5; the upper assembly includes a support ear 6, an upper slide rail 7 and a slider assembly 8. An annular upper slide rail 7 is installed above the clamping device 1, and a slider assembly 8 that can slide around the outer side of the upper slide rail 7 is installed on the upper slide rail 7. The central guide tube 4 is arranged in the center of the clamping device 1, and the height of the central guide tube 4 can be adjusted to locate the position of the radiation source.

[0038] The clamping device 1 is composed of two semicircular structures (skeletons), connected by a quick clamp, and tightly fitted with the impeller mating surface through the adjustment block 3. The positioning block 2 accurately positions the device on the impeller. The lower connecting bar 5 connects the clamping device 1 and the central conduit 4, while ensuring that the central conduit 4 is located in the center. The lower connecting bar 5 adopts a rib plate structure to increase its strength. The height of the central conduit 4 is adjustable to accurately locate the position of the radiation source during panoramic exposure. The four adjustment blocks 3 are respectively installed at the connection between the four ears 6 and the clamping device 1, and fixed to the positioning assembly by screws.

[0039] The central conduit 4 is fixed to the center of the impeller through the lower connecting strip 5. The source conduit equipped with the radiation source is inserted into the central conduit 4. The focal length is adjusted by adjusting the height of the central conduit 4, which reduces the difficulty of focusing in panoramic exposure. Through precise center positioning, the focusing accuracy is improved, the blackness difference of the film and the difficulty of film processing are reduced, and the one-time success rate of the film is increased.

[0040] The lug 6 connects the clamping device 1 and the upper slide rail 7. The slider assembly 8 is placed on the upper slide rail 7 and can rotate 360° around the impeller along the track. A scale from 0° to 360° is engraved on the upper slide rail 7. Preferably, the clamping device 1, the central conduit 4 and the upper slide rail 7 are coaxially arranged to ensure the accuracy of the spatial positioning of the radiation source and the inspected weld.

[0041] like Figure 5 and Figure 6 As shown, the slider assembly 8 includes a column 9, a guide tube 10 and a base 11. The column 9 is adjustable in height, and the guide tube 10 is adjustable in extension length. At the same time, the guide tube 10 can rotate 360 ​​degrees with the column 9 as the center, so as to accurately locate the radiation source position during single-wall exposure. In other words, the column 9 on the slider 8 adopts a cylindrical design, so that the guide tube 10 can be adjusted up and down along the column 9, and can also be rotated with the column 9 as the center, so that the radiation source position can be adjusted in all directions to adapt to different specifications of reactor main coolant pump impeller blades.

[0042] Insert the source conduit with the radiation source into the conduit 10 on the slider 8, and accurately locate the radiation source by adjusting the position of the slider 8 on the upper slide rail 7, the height of the column 9, the extension length of the conduit 10, and the rotation angle. Then move the slider 8 60° along the track to the next blade to achieve the radiation source positioning work of the next blade, and so on, until all inspection work is completed. Through this method, the accuracy of radiation source positioning is increased, the workload of radiation source positioning is reduced, consistent exposure conditions are guaranteed, the difficulty of film processing is reduced, and the first-time success rate of film is increased.

[0043] The positioning function of the source positioning device for the radiographic inspection of the impeller blades of the reactor main coolant pump provided by the present invention is completed by the cooperation of the positioning assembly, the lower assembly and the upper assembly. Each component is modularly designed and connected by screws or quick clamps. The assembly process is as follows:

[0044] Insert the central conduit 4 into the corresponding position of the lower connecting strip 5 to complete the assembly of the lower component; connect the support ear 6 and the upper slide rail 7 together by screws to form two semicircular structures, and install the slider 8 into the upper slide rail 7 along the track to complete the assembly of the upper component; install the positioning block 2 and the adjustment block 3 to the corresponding positions of the clamping device 1 by screws to complete the assembly of the lower component.

[0045] Connect the assembled lower and upper components to the clamping device 1 with screws to form two semicircular structures. Then place the two semicircular structures of the clamping device 1 on the annular component at the bottom of the impeller. The positioning block 2 bears the weight of the equipment itself and determines the axial position of the device. Lock the quick clamp, and then connect the upper slide rail 7 with screws to complete the equipment installation. The circumferential position of the positioning device is accurately located by adjusting the relative position of the device and the impeller blades to ensure the positioning repeatability of the positioning device. Then tighten the adjustment block 3 to complete the installation of the positioning device.

[0046] When performing central transillumination, the central catheter 4 is fixed to the center of the impeller through the lower connecting strip 5, and the source catheter equipped with the radiation source is inserted into the central catheter 4. The focal length is adjusted by adjusting the height of the central catheter 4 to complete the positioning work.

[0047] When performing single-wall radiography, the source catheter equipped with the radiation source is inserted into the catheter 10 on the slider 8. The position of the radiation source is accurately located by adjusting the position of the slider 8 on the upper slide rail 7, the height of the column 9, the extension length of the catheter 10 and the rotation angle. Then, the slider 8 is moved 60° along the track toward the next blade to achieve the radiation source positioning work of the next blade, and so on, until all inspection work is completed.

[0048] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A source positioning device for radiographic inspection of reactor main coolant pump impeller blades, characterized in that: The invention comprises a clamping device (1) and a central catheter (4), wherein the clamping device (1) is an annular structure in which two semicircular frames are connected by a quick clamp, a positioning block (2) is provided on the inner side of the clamping device (1), the bottom of the central catheter (4) is connected to the clamping device (1) via a lower connecting bar (5), an annular upper slide rail (7) is provided above the clamping device (1), a slidable slider assembly (8) is provided on the upper slide rail (7), the bottom of the central catheter (4) is connected to the clamping device (1) via the lower connecting bar (5), the central catheter (4) is passed through the center of the clamping device (1), and the height of the central catheter (4) can be adjusted to locate the position of the radiation source; the clamping device (1), the central catheter (4) and the upper slide rail (7) are coaxially arranged; The upper slide rail (7) is fixedly connected to the clamping device (1) via a support ear (6); an adjustment block (3) is provided on the clamping device (1); the adjustment block (3) is installed at the connection between the support ear (6) and the clamping device (1); and a scale value is provided on the upper surface of the upper slide rail (7); The slider assembly (8) comprises a column (9), a guide tube (10) and a base (11); the column (9) is arranged on the base (11) in a height-adjustable manner; and the guide tube (10) is arranged on the column (9) in a rotatable and telescopic manner.

2. The source positioning device for radiographic inspection of reactor primary coolant pump impeller blades according to claim 1, characterized in that: The lower connecting strip (5) is a rib plate structure.

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