Vertical detection system for fuel assembly

Abstract

The invention provides a fuel assembly vertical detection system, and belongs to the technical field of nuclear industry detection. The system comprises a waterproof radiation shielding box body, an underwater radiation-resistant glass window, a metal reflecting mirror, an industrial lens, a camera, an electric displacement table, a fixed bracket, a waterproof connector and the like. An underwater radiation-resistant glass window is arranged on the end face of the waterproof radiation shielding box body, the metal reflector vertically turns a light path, the industrial camera is arranged along the turning light path, the electric displacement table is used for adjusting the imaging distance, and the connector is connected with external equipment. A tungsten alloy radiation-resistant shielding layer is lined in the waterproof radiation shielding box body, the underwater radiation-resistant glass window is made of cerium-containing radiation-resistant glass, and the metal reflecting mirror is made of pure copper and forms an angle of 45 degrees with an optical axis. The system adopts a vertical light path layout of single 90-degree turning, is short in light path, simple and convenient to install and adjust, small in thermal disturbance influence, easy to correct, few in quick-wear parts, convenient to replace, free of large-area bottom surface support and space-saving, and is structurally suitable for nondestructive testing of the nuclear fuel assembly.

Description

Technical Field

[0001] This invention relates to the field of nuclear industry testing technology, and in particular to a vertical testing system for fuel assemblies. Background Technology

[0002] When inspecting fuel assemblies, a specific optical path layout is typically used to avoid damaging or malfunctioning sensors by directly exposing them to the radiation source. A horizontal measurement system is a common choice, employing a periscope-style horizontal optical path layout and performing measurements through two optical path folds.

[0003] However, horizontal measurement systems have several drawbacks: First, the two optical path folds require extremely high overall assembly precision, making assembly difficult; second, the two folds result in a longer internal optical path, which, in underwater measurement environments, is significantly affected by underwater thermal disturbances, amplifying the disturbances and thus impacting the recovery effect of the disturbance algorithm, reducing measurement accuracy; third, each fold relies on a metal reflector, and if one of the reflectors fails due to radiation pitting, the entire system needs to be replaced, increasing maintenance costs and shortening the overall lifespan; finally, horizontal measurement systems require a large platform support area, limiting their application in space-constrained measurement scenarios.

[0004] To overcome the aforementioned shortcomings of horizontal measurement systems, a new measurement system needs to be designed. Vertical measurement systems have emerged as a result, offering advantages such as shorter optical path length, easier mirror assembly and adjustment, easier correction of thermal disturbances, fewer vulnerable parts, and convenient replacement. These features effectively solve the problems of horizontal measurement systems and meet the requirements for fuel assembly testing. Summary of the Invention

[0005] The purpose of this invention is to provide a vertical fuel assembly inspection system that, by optimizing the optical path layout and structural design, solves the problems of traditional horizontal measurement systems, such as high assembly difficulty, susceptibility to thermal disturbances, high maintenance costs, and large space occupation, thereby achieving lightweight, miniaturized, high-precision, and high-reliability nuclear fuel assembly inspection.

[0006] To achieve the above objectives, the present invention provides a vertical fuel assembly testing system, comprising:

[0007] The waterproof radiation shielding enclosure has an underwater radiation-resistant glass window on the end face facing the fuel assembly.

[0008] A metal reflector, positioned behind an underwater radiation-resistant glass viewing window, is used to vertically deflect the optical path of the fuel rod under test.

[0009] Industrial cameras and lenses are positioned along the direction of the refracted optical path;

[0010] An electric displacement stage, installed inside a waterproof radiation shielding enclosure, is used to fix and adjust the imaging distance of an industrial camera and a dual telecentric lens along the optical axis.

[0011] Waterproof connectors are located on the upper surface of the waterproof radiation shielding enclosure and are used to connect to external control equipment.

[0012] Preferably, the inner lining of the waterproof radiation shielding box is provided with a tungsten alloy radiation-resistant metal shielding layer.

[0013] Preferably, the underwater radiation-resistant glass window is made of cerium-containing radiation-resistant glass.

[0014] Preferably, the metal reflector is a 90° metal reflector.

[0015] Preferably, the 90° metal mirror is made of pure copper by single-point diamond turning, and the reflecting surface forms a 45° angle with the optical axis.

[0016] Preferably, the lens of the industrial camera is a double telecentric lens.

[0017] Therefore, the present invention employs the above-described vertical fuel assembly testing system, and the beneficial technical effects are as follows:

[0018] (1) The vertical optical path layout with a single 90° folding is adopted, which greatly shortens the optical path length. This makes the mirror assembly and adjustment process simpler and easier, reduces the assembly difficulty and dependence on high-precision assembly technology, and reduces assembly time and cost.

[0019] (2) Due to the shorter optical path, the distortion and loss caused by underwater thermal disturbance are relatively small, which makes it easier to use algorithms to make accurate corrections at the imaging end, thereby effectively improving the accuracy and stability of the measurement results and ensuring that high-quality image data can still be obtained in complex underwater measurement environments.

[0020] (3) The system only requires one metal mirror as a vulnerable part, which reduces the number of failure points, reduces the risk of image quality fluctuations caused by mirror failure, improves the stability of image quality, and is conducive to long-term stable measurement work.

[0021] (4) The design of a single metal reflector makes the replacement operation simpler and more convenient, without the need for large-scale disassembly and reassembly of the entire system, which shortens maintenance time, reduces maintenance costs, and improves the maintainability and efficiency of the system.

[0022] (5) No large-area bottom platform is required for support, saving space resources and enabling it to adapt to more space-constrained measurement scenarios, thus expanding the application scope of the system. Attached Figure Description

[0023] Figure 1This is a schematic diagram of the external structure of a vertical fuel assembly testing system according to the present invention;

[0024] Figure 2 This is a perspective view of the internal structure of a vertical fuel assembly testing system according to the present invention;

[0025] Figure 3 This is a schematic diagram of the internal structure of a vertical fuel assembly detection system according to the present invention.

[0026] Figure Labels

[0027] 1. Waterproof radiation shielding enclosure; 2. Metal reflector; 3. Industrial camera; 4. Underwater radiation-resistant glass window; 5. Electric displacement stage. Detailed Implementation

[0028] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0030] Example 1

[0031] like Figures 1-3 As shown, a vertical fuel assembly testing system includes the following main components:

[0032] The waterproof radiation shielding box 1 has an underwater radiation-resistant glass window 4 at the end facing the fuel assembly, which is used for the entry of light.

[0033] The underwater radiation-resistant glass window 4 is made of cerium-containing radiation-resistant glass.

[0034] Tungsten alloy radiation-resistant metal shielding layer: installed inside the waterproof radiation shielding box 1. The thickness of the shielding layer varies from 20mm to 80mm depending on the radiation dose of the measurement environment, in order to enhance radiation protection.

[0035] The 90° metal reflector 2 is made of pure copper by single-point diamond turning. The reflective surface is at a 45° angle to the optical axis. It is installed behind the underwater radiation-resistant glass window 4 and is used to vertically fold the optical path of the fuel rod to be tested.

[0036] The vertical optical path layout, employing a single 90° fold, significantly shortens the optical path length. This design simplifies the mirror assembly and adjustment process, reduces reliance on high-precision assembly techniques, and decreases assembly time and costs. Simultaneously, the shorter optical path effectively reduces the impact of underwater thermal disturbances. The distortion and falsification caused by thermal disturbances are relatively small, facilitating precise correction via algorithms at the imaging end. This ensures the accuracy and stability of the measurement results, enabling the acquisition of high-quality image data even in complex underwater measurement environments.

[0037] Only one metal reflector 2 is required as a vulnerable component, reducing potential failure points, lowering the risk of image quality fluctuations due to reflector failure, improving imaging stability, and facilitating long-term stable measurements. Furthermore, replacing a single reflector is simple and convenient, eliminating the need for large-scale disassembly and reassembly of the entire system, shortening maintenance time, reducing maintenance costs, and improving system maintainability and efficiency.

[0038] Industrial camera 3 is mounted behind the 90° metal reflector 2, set along the direction of the refracted light path. The lens is a double telecentric lens, and its parameter selection is similar to that for measurement in an air environment, except that the change in the measurement object distance caused by the refractive index in water needs to be considered.

[0039] The electric displacement stage 5 is installed inside the waterproof radiation shielding box 1 to fix the industrial camera 3 and the dual telecentric lens, and to adjust the imaging distance along the optical axis.

[0040] The electric displacement stage 5 precisely adjusts the imaging distance of the industrial camera 3 and the dual telecentric lenses along the optical axis to ensure that clear images are obtained within a specific depth range of the area to be measured, meeting the fine inspection requirements of fuel assemblies of different positions or sizes, and improving the accuracy and flexibility of imaging.

[0041] In complex measurement environments such as underwater, manual adjustment is difficult and has limited accuracy. However, the electric adjustment method of the electric displacement stage 5 can stably respond to control commands and can still achieve precise adjustment even in the presence of environmental interference, thus ensuring the stability and reliability of the measurement.

[0042] Meanwhile, the electric displacement stage 5 can be connected to the onshore electrical control box via waterproof connectors. The electrical control box is connected to the host computer, which can set parameters such as the step size, speed, and pause time of the electric displacement stage, and control the switching of the light source. This facilitates automated adjustment and can be linked with other automated processes such as image acquisition and data processing, laying the hardware foundation for building a fully automated detection system and improving the level of intelligence in detection.

[0043] The fixed bracket rigidly fixes the electric displacement stage to ensure its stable position in the underwater environment, avoids imaging distance deviation caused by water flow disturbance or equipment operation vibration, and ensures measurement accuracy.

[0044] Waterproof connectors are installed on the upper surface of the waterproof radiation shielding enclosure 1 and are used to connect external control equipment.

[0045] Installation method.

[0046] Step S1: Preparation and lining installation of waterproof radiation shielding box 1.

[0047] Prepare a waterproof radiation shielding enclosure 1, and open an underwater radiation-resistant glass window 4 at the end of it that faces the fuel assembly.

[0048] A tungsten alloy radiation-resistant metal shielding layer of a certain thickness is installed inside the waterproof radiation shielding box 1 to ensure that it covers the top, bottom, left, right and front inner layers of the box, thereby enhancing the system's radiation protection capability.

[0049] Step S2: Installation of underwater radiation-resistant glass window 4.

[0050] Ensure that the glass is free from defects such as cracks, breakage, and bubbles, and guarantee its airtightness with the waterproof radiation shielding box 1.

[0051] Step S3: Installation of the 90° metal reflector 2.

[0052] A 90° metal reflector 2 is installed behind the underwater radiation-resistant glass window 4. The 90° metal reflector 2 is made of pure copper by single-point diamond turning. The reflective surface is at a 45° angle to the optical axis to ensure that the optical path can be accurately folded vertically.

[0053] Step S4: Installation of industrial camera 3 and double telecentric lens.

[0054] The dual telecentric lens is mounted on the industrial camera 3, and the industrial camera 3 and its lens are mounted on an electric displacement stage parallel to the optical path.

[0055] The electric displacement stage 5 is fixed to the rear end face inside the waterproof radiation shielding box 1 to ensure a stable connection between it and the box.

[0056] Step S5: Installation of waterproof connectors.

[0057] Drill holes on the upper surface of the waterproof radiation shielding box 1 and install waterproof connectors to connect external control equipment, ensuring the communication and control of the equipment.

[0058] Step S6: Sealing the system.

[0059] After debugging, place the radiation-resistant sealing ring in the mounting groove at the top of the waterproof radiation shielding box 1, close the cover plate, and tighten the internal hex screws to ensure the sealing of the entire system.

[0060] Measurement method.

[0061] (1) System assembly and debugging.

[0062] The assembled industrial camera 3 was placed on the underwater measuring platform and secured.

[0063] Adjust the three parameters of the industrial camera, such as exposure time, object distance, and light source power, to acquire an image of the object under test.

[0064] The quality of an image is determined by using an underwater adaptive edge extraction algorithm and visual observation of whether the edges of the image are clear.

[0065] (2) Measurement process.

[0066] By adjusting the electric displacement stage 5, precise control of the imaging distance can be achieved, ensuring that a clear image can be observed within a certain depth range in the area to be measured.

[0067] After repeated adjustments, the optimal measurement parameters for the measurement environment were obtained, and the measurement was completed.

[0068] Through the above-described structural design, installation method, and measurement method, the vertical measurement system of the present invention can achieve high-precision non-destructive testing of nuclear fuel assemblies, while possessing good waterproof and radiation-resistant properties, making it suitable for complex underwater measurement environments.

[0069] It is worth noting that all contents not described in detail in this invention are existing technologies and are well known to those skilled in the art.

[0070] Therefore, the present invention adopts the above-mentioned vertical fuel assembly detection system, which solves the problems of traditional horizontal measurement systems such as high assembly difficulty, susceptibility to thermal disturbance, high maintenance cost, and large space occupation by optimizing the optical path layout and structural design, and realizes lightweight, miniaturized, high-precision and high-reliability nuclear fuel assembly detection.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A fuel assembly vertical detection system, characterized by, The application relates to a fuel rod radiation shielding box. The underwater radiation-resistant glass window is made of cerium-containing radiation-resistant glass. The 90-degree metal mirror is made of pure copper and is single-point diamond turned, and the reflection surface is at a 45-degree angle with the optical axis. The lens of the industrial camera is a double-telecentric lens. ​ ​ 2. A vertical fuel assembly inspection system as described in claim 1, wherein, ​ 3. The vertical fuel assembly inspection system of claim 1, wherein, ​ 4. The vertical fuel assembly inspection system of claim 1, wherein, ​ 5. The vertical fuel assembly inspection system of claim 1, wherein, ​ 6. The vertical fuel assembly inspection system of claim 1, wherein, ​

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