X-ray detection device for MOX fuel assembly welding seam

Abstract

The invention belongs to the technical field of nuclear fuel detection, and particularly relates to an X-ray detection device for MOX fuel assembly welding seams. The device comprises a control system, an X-ray shielding chamber, an imaging detection system and an X-ray emission system, the control system is arranged outside the X-ray shielding chamber and is connected with the imaging detection system and the X-ray emission system so as to control the imaging detection system and the X-ray emission system; the imaging detection system and the X-ray emission system are arranged in the X-ray shielding chamber and used for conducting X-ray detection on the MOX fuel assembly welding seam. The X-ray digital imaging high-sensitivity on-line automatic detection of the MOX fuel assembly weld defect is realized, the blank in the prior art is filled, and the X-ray digital imaging high-sensitivity on-line automatic detection device is ingenious in design, convenient to use and suitable for being applied to the on-line X-ray digital imaging high-sensitivity detection of the MOX fuel assembly weld defect.

Description

Technical Field

[0001] The present application belongs to the technical field of nuclear fuel detection, and in particular relates to an X-ray detection device for a weld of a MOX fuel assembly. Background Art

[0002] Nuclear safety is the lifeline of nuclear power development. MOX fuel (UO2 and PuO2 mixed fuel) assemblies are the core components of fast neutron nuclear reactors. Under complex working conditions such as high temperature and pressure, high-speed erosion and corrosion of sodium coolant, and strong neutron radiation field, the fuel assembly structure and its weld joints may also be subjected to chemical effects of fissionable materials and complex mechanical loads, which will threaten the safe operation of fast neutron nuclear reactors. In view of this, the performance of the fuel assembly welds must be inspected by non-destructive testing such as X-rays to fully ensure the safe operation of nuclear reactors.

[0003] The welded structure of the MOX fuel assembly is a stainless steel material with a regular hexagon on the outside and a hollow circle structure on the inside. Its cross-section is a regular hexagon, and the opposite side dimension is 112mm, which requires that the outer surface of the assembly and the inside of the hollow circle be compensated at the same time, so that the thickness of the compensated assembly can be uniform and the contrast is good. However, the welding of the assembly has been completed in the actual process, and the hollow circle part inside cannot be compensated. Its transillumination thickness will change significantly, making it difficult to guarantee edge sensitivity, and defects may be missed. In addition, the MOX fuel assembly itself emits strong gamma rays, and ordinary detection equipment cannot meet the detection requirements, resulting in large scattered rays, affecting the detection sensitivity, etc. Summary of the invention

[0004] The purpose of the present application is to provide an X-ray detection device for MOX fuel assembly welds, so as to solve the problem that ordinary detection equipment in the prior art cannot meet the detection requirements of MOX fuel assemblies.

[0005] Technical solution to achieve the purpose of this application: The embodiment of the present application provides an X-ray detection device for a weld of a MOX fuel assembly, the device comprising: a control system, an X-ray shielding room, an imaging detection system, and an X-ray emission system; The control system is arranged outside the X-ray shielding room and connected with the imaging detection system and the X-ray emission system to realize the control of the imaging detection system and the X-ray emission system; The imaging detection system and the X-ray emission system are arranged in the X-ray shielding room and are used for X-ray detection of the welds of the MOX fuel assembly.

[0006] Optionally, the device further comprises: a cooling circulation system; The cooling circulation system is arranged outside the X-ray shielding room and is used for cooling the X-ray emission system.

[0007] Optionally, an X-ray emitting system includes: a ray head; The ray machine head is movably fixed on the first supporting platform, and the emission section is opposite to the imaging detection system.

[0008] Optionally, a first copper foil is placed at the emitting head of the X-ray machine head.

[0009] Optional, imaging detection system, including: image quality meter, flat panel detector and lead intensifying screen; The flat-panel detector and the lead intensifying screen are movably fixed on the second supporting platform; the lead intensifying screen is arranged at the front end of the flat-panel detector; A second copper foil is placed at the detection port of the imaging detection system, and the image quality meter is fixed at the front end of the second copper foil.

[0010] Optionally, a through hole is provided on the second supporting platform for the MOX fuel assembly to pass through.

[0011] Optionally, a pit for placing the MOX fuel assembly is provided in the X-ray shielding room.

[0012] The beneficial technical effects of this application are: An X-ray detection device for a weld of a MOX fuel assembly provided in an embodiment of the present application includes: a control system, an X-ray shielding room, an imaging detection system, and an X-ray emission system; the control system is arranged outside the X-ray shielding room, connected to the imaging detection system and the X-ray emission system, to realize control of the imaging detection system and the X-ray emission system; the imaging detection system and the X-ray emission system are arranged in the X-ray shielding room, and are used to perform X-ray detection on the weld of the MOX fuel assembly. The embodiment of the present application realizes the high-sensitivity online automatic detection of defects in the weld of the MOX fuel assembly by X-ray digital imaging, filling the gap in the prior art. The present invention is ingeniously designed, easy to use, and suitable for application in the high-sensitivity online detection of defects in the weld of the MOX fuel assembly by X-ray digital imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of the structure of an X-ray detection device for a weld of a MOX fuel assembly provided in an embodiment of the present application; Figure 2 A schematic structural diagram of another X-ray detection device for MOX fuel assembly welds provided in an embodiment of the present application. In the figure: 1-control system; 2-cooling circulation system; 3-first supporting platform; 4-X-ray shielding room; 5-imaging detection system; 6-X-ray emission system; 7-ray head; 8-first copper foil; 9-flat panel detector; 10-lead intensifying screen; 11-second supporting platform; 12-second copper foil; 13-MOX fuel assembly; 14-X-ray. DETAILED DESCRIPTION

[0014] In order to make those skilled in the art better understand the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the embodiments described below are only a part of the embodiments of the present application, not all. Based on the embodiments recorded in the present application, all other embodiments obtained by those skilled in the art without paying creative work are within the scope of protection of the present application.

[0015] See also Figure 1 , which is a schematic diagram of the structure of an X-ray detection device for MOX fuel assembly welds provided in an embodiment of the present application.

[0016] An X-ray detection device for a weld of a MOX fuel assembly provided in an embodiment of the present application comprises: a control system 1, an X-ray shielding room 4, an imaging detection system 5 and an X-ray emission system 6; The control system 1 is arranged outside the X-ray shielding room 4, and is connected to the imaging detection system 5 and the X-ray emission system 6, so as to realize the control of the imaging detection system 5 and the X-ray emission system 6; The imaging detection system 5 and the X-ray emission system 6 are arranged in the X-ray shielding room 4 and are used to perform X-ray detection on the welds of the MOX fuel assembly.

[0017] In a specific example, the control system 1 may have two operating modes, manual and automatic, to control the equipment to implement X-ray inspection of component welds, which may mainly include loading, component rotation, weld detection, re-inspection and other actions.

[0018] The X-ray shielding room 4 is used to shield X-rays. In the specific implementation, the MOX fuel assembly 13 is transferred to the X-ray detection station in the X-ray shielding room 4 by the overhead crane. After the weld position is determined, the parameters of the X-ray emission system 6 are adjusted, and X-rays are emitted to form a digital image of the weld on the imaging detection system 5. The image analysis software with an enhanced image quality algorithm is used to analyze the detection results to form an image that can be judged. The entire measurement process is operated by the equipment automation, and personnel can perform online operation and control in the remote control room. As an example, the device can also include a component clamping device, including components such as a cylinder and a chuck, for fixing the MOX fuel assembly 13.

[0019] In one example, the device may further include: a cooling circulation system 2; The cooling circulation system 2 is arranged outside the X-ray shielding room 4 and is used to cool the X-ray emission system 6 .

[0020] In some possible implementations of the present application, such as Figure 2 As shown, the X-ray emitting system 6 comprises: a ray head 7; The X-ray machine head 7 is movably fixed on the first supporting platform 3 , and the emission section is opposite to the imaging detection system 5 .

[0021] As an example, the X-ray machine head 7 can adopt a high-penetration, high-power, high-voltage bipolar X-ray tube. The X-ray machine adopts stepless control of KV and MA, and is easy to install, integrate and operate. It can be suitable for factory applications. It also has high penetration, relatively short exposure time and good reliability. The unique anti-arcing design can improve efficiency.

[0022] In one example, a first copper foil 8 is placed at the emitting head of the X-ray machine head 7 .

[0023] It should be noted that the first copper foil 8 can reduce scattering and background interference to the greatest extent, improve the contrast and resolution of detection, and improve the sensitivity and accuracy of detection.

[0024] In some possible implementations of the embodiments of the present application, the imaging detection system 5 includes: an image quality meter, a flat panel detector 9 and a lead intensifying screen 10; The flat panel detector 9 and the lead intensifying screen 10 are movably fixed on the second supporting platform 11; the lead intensifying screen 10 is arranged at the front end of the flat panel detector 9; A second copper foil 12 is placed at the detection port of the imaging detection system 5 , and the image quality meter is fixed to the front end of the second copper foil 12 .

[0025] It can be understood that the lead intensifying screen 10 is located in front of the flat-panel detector 9, which can enhance the intensity of the detection signal, reduce scattering and background interference, and make the detected image clearer and more obvious.

[0026] In one example, the second copper foil 12 can minimize scattering and background interference, and improve the contrast and resolution of detection. The second supporting platform 11 is provided with a through hole for the MOX fuel assembly 13 to pass through.

[0027] In some possible implementations of the embodiment of the present application, a pit for placing the MOX fuel assembly 13 is provided in the X-ray shielding room 4 .

[0028] The following describes in detail the specific steps of performing X-ray inspection of welds of MOX fuel assemblies using an X-ray inspection device for welds of MOX fuel assemblies provided in an embodiment of the present application with reference to a specific example.

[0029] 1) Preparation Check the equipment to ensure that it is operating normally and the calibration equipment is within the validity period. Check the component model and number to see if they are consistent with the transmitted information. Confirm whether there is any damage on the surface of the component, and record it if there is any damage. During the entire inspection process, avoid component damage and determine the inspected area, which should include weld metal and heat-affected zone.

[0030] 2) Inspection and treatment of the inspected area Before the radiographic inspection of the component welds, the surface of the welded joints shall be inspected and qualified. The inspected surface shall be free of any irregular conditions such as oxides, foreign matter, scratches, etc. that may hinder the radiographic assessment. Otherwise, the welds shall be properly cleaned and trimmed.

[0031] 3) Transillumination method and parameters The MOX fuel assembly weld adopts double-wall single-image transillumination technology, and the transillumination is performed 6 times at equal angles. The fuel assembly is hoisted and sent to the inspection area, and the weld of the fuel assembly should be directly aligned with the vertical position of the center of the focus. The image quality meter is placed at the thinnest transillumination thickness position. The assembly and weld outer surface are inspected by the assembly weld X-ray detection equipment.

[0032] When the X-ray machine adopts 1mm large focus, 1000mm penetration focal length, 6mA penetration current, 6min penetration time, 132kV tube voltage, and adopts direct penetration method, double-wall single-shadow penetration mode, and penetrates different weld surfaces of the component 6 times, it is an ideal detection process parameter. The inspection penetration mode is divided into automatic penetration and manual penetration, and the automatic penetration mode is preferred.

[0033] The component transfer vehicle transfers the component through the opening on the roof of the X-ray shielding room and transfers the component to the required position in the X-ray shielding room and places the characteristic edge of the hexagonal weld in the required orientation (orientation error ±1°). After completing the filming of one edge, the transfer vehicle rotates the component 60° for the next filming. After the six edges are filmed, the component is transferred out of the X-ray shielding room. The inspectors process and evaluate the images and make a conclusion on whether the weld is qualified based on the evaluation results.

[0034] 4) Judgment criteria Under the condition that two φ0.25mm holes of the step hole quality meter are visible, two pores with a size not greater than 0.6mm are allowed to exist, and the pore spacing is not less than 6 times the maximum pore size. Obvious bulging, cracks and slag inclusions are not allowed in the weld area. If the quality of the radiographic image meets the following requirements, it is allowed to be evaluated: a) There should be no obvious uneven pixel points such as spots and stripes on the grayscale image of the transmission section of the weld and the surrounding area to be measured that affect the evaluation; the dual-wire image quality meter should measure the resolution of the image: the 0.13mm wire diameter of the D9 wire number should be clearly visible on the image. If there is obvious unevenness, re-modeling is required; b) The relevant identification marks can be seen on the image, and the step hole of the image quality indicator should be clearly visible on the image. If there is incomplete penetration, the X-ray will not be judged.

[0035] An X-ray detection device for a weld of a MOX fuel assembly provided in an embodiment of the present application includes: a control system, an X-ray shielding room, an imaging detection system, and an X-ray emission system; the control system is arranged outside the X-ray shielding room, connected to the imaging detection system and the X-ray emission system, to realize control of the imaging detection system and the X-ray emission system; the imaging detection system and the X-ray emission system are arranged in the X-ray shielding room, and are used to perform X-ray detection on the weld of the MOX fuel assembly. The embodiment of the present application realizes the high-sensitivity online automatic detection of defects in the weld of the MOX fuel assembly by X-ray digital imaging, filling the gap in the prior art. The present invention is ingeniously designed, easy to use, and suitable for application in the high-sensitivity online detection of defects in the weld of the MOX fuel assembly by X-ray digital imaging.

[0036] The present application is described in detail above in conjunction with the accompanying drawings and embodiments, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present application. Any content not described in detail in the present application can adopt the existing technology.

Claims

1. An X-ray inspection device for MOX fuel assembly welds, characterized in that: The device comprises: a control system (1), an X-ray shielding room (4), an imaging detection system (5) and an X-ray emission system (6); The control system (1) is arranged outside the X-ray shielding room (4), connected to the imaging detection system (5) and the X-ray emission system (6), and realizes control of the imaging detection system (5) and the X-ray emission system (6); The imaging detection system (5) and the X-ray emission system (6) are arranged in the X-ray shielding room (4) and are used to perform X-ray detection on the welds of the MOX fuel assembly.

2. The X-ray detection device for MOX fuel assembly weld according to claim 1, characterized in that: The device further comprises: a cooling circulation system (2); The cooling circulation system (2) is arranged outside the X-ray shielding room (4) and is used to cool the X-ray emission system (6).

3. The X-ray detection device for MOX fuel assembly welds according to claim 1, characterized in that: The X-ray emitting system (6) comprises: a ray machine head (7); The ray machine head (7) is movably fixed on the first supporting platform (3), and the emission section is opposite to the imaging detection system (5).

4. The X-ray detection device for MOX fuel assembly welds according to claim 3, characterized in that: A first copper foil (8) is placed at the emitting head of the ray machine head (7).

5. The X-ray detection device for MOX fuel assembly welds according to claim 3, characterized in that: An imaging detection system (5) comprising: an image quality meter, a flat panel detector (9) and a lead intensifying screen (10); The flat panel detector (9) and the lead intensifying screen (10) are movably fixed on the second supporting platform (11); the lead intensifying screen (10) is arranged at the front end of the flat panel detector (9); A second copper foil (12) is placed at the detection port of the imaging detection system (5), and the image quality meter is fixed to the front end of the second copper foil (12).

6. The X-ray detection device for MOX fuel assembly welds according to claim 5, characterized in that: The second supporting platform (11) is provided with a through hole for the MOX fuel assembly (13) to pass through.

7. The X-ray detection device for MOX fuel assembly welds according to any one of claims 1 to 6, characterized in that: A pit for placing the MOX fuel assembly (13) is provided in the X-ray shielding room (4).

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