Compact multifunctional integrated nuclear fuel rod strip detection probe

Abstract

The invention discloses a compact multifunctional integrated nuclear fuel rod strip detection probe which comprises a probe body, a probe support, an eddy current detection unit, a temperature sensing unit and an inclination angle sensing unit. According to the compact multifunctional integrated nuclear fuel rod strip detection probe, the eddy current detection unit and the temperature sensing unit are integrated in the probe main body, and meanwhile, the temperature sensing unit is arranged, so that multi-parameter cooperative work of oxide film thickness detection, temperature compensation and attitude monitoring is realized; the technical problems that in the prior art, due to temperature drift and probe posture deviation, the oxidation film thickness detection precision is low, the stability is poor, and the environmental adaptability is weak are solved, and in-situ, online and high-precision detection of the nuclear fuel rod cladding strip can be achieved in a narrow space and an automatic detection environment. And the intelligent level and the engineering practicability of the detection system are obviously improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nuclear fuel assembly detection, and particularly relates to a compact multifunctional integrated nuclear fuel rod strip detection probe. BACKGROUND

[0002] In the nondestructive testing process of the nuclear fuel assembly strip component, the oxide film thickness is a core index for evaluating the corrosion state of the cladding material and the service safety, and the eddy current detection technology is often used for non-contact measurement. However, the traditional eddy current detection probe system still has the key problems of detection precision decline, poor repeatability and weak adaptability caused by environmental temperature interference and probe space attitude out of control in actual engineering application, which specifically shows the following two aspects: (1) The problem of detection precision deviation caused by temperature interference, the eddy current detection principle depends on the change of the electromagnetic property of the measured material, and the conductivity and magnetic permeability of the material are highly sensitive to temperature. In the process of nuclear fuel strip manufacturing, storage or in-service inspection, local environmental temperature fluctuation (such as coolant temperature change, equipment heat radiation, friction heat generation, etc.) will directly cause the eddy current signal to drift, resulting in systematic deviation of the oxide film thickness inversion result. Therefore, a micro temperature sensor integrated on the probe body or the probe support is urgently needed to realize synchronous acquisition, spatial co-location and real-time compensation of the eddy current detection signal, so as to improve the stability and accuracy of the oxide film thickness measurement under variable temperature conditions.

[0003] (2) The problem of signal distortion and detection failure caused by probe attitude deviation, the eddy current detection is extremely sensitive to the lift-off distance and relative inclination angle between the probe and the measured surface. In the automatic detection or complex curved surface fitting scene, due to mechanical vibration, guide rail error, installation deviation or strip surface undulation, the probe is prone to small inclination angle deviation (such as pitch angle and roll angle change), which causes abnormal signal amplitude and phase, low signal-to-noise ratio and poor data repeatability. Therefore, a design scheme of directly integrating a micro inclination angle sensor on the probe support structure is urgently needed to enable the probe to have the function of "space attitude self-sensing", realize real-time inclination angle monitoring, data marking and closed-loop attitude compensation, so as to ensure the consistency, repeatability and engineering robustness of the detection process. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a compact multifunctional integrated nuclear fuel rod strip detection probe.

[0005] The technical scheme adopted by the present application to solve the technical problem is that a compact multifunctional integrated nuclear fuel rod strip detection probe is constructed, which comprises a probe body, a probe support, an eddy current detection unit, a temperature sensing unit and an inclination angle sensing unit. The probe body is connected to the probe support, and the eddy current detection unit is integrated in the probe body and used to collect the eddy current response signal of the surface of the nuclear fuel rod strip and to invert the oxide film thickness. The temperature sensing unit is integrated in the probe body and arranged adjacent to the eddy current detection unit, and is used to collect the temperature of the working environment of the eddy current detection unit in real time, and to provide a reference for temperature drift compensation of the eddy current detection signal. The inclination sensing unit is integrated on the probe support, and is used to monitor the attitude change of the probe body during detection and to output an attitude compensation signal.

[0006] In some embodiments, the probe body includes a probe shell and a strip probe skeleton installed in the probe shell, and the eddy current detection unit is installed at both ends of the strip probe skeleton, and the strip probe skeleton is provided with a positioning groove for installing the temperature sensing unit.

[0007] In some embodiments, the probe body further includes a top shell connected to the probe shell and an alumina film located between the top shell and the strip probe skeleton, and the internal gap of the probe shell is sealed with sealant.

[0008] In some embodiments, the eddy current detection unit includes a pair of planar spiral coils with completely symmetrical geometric parameters and a full-bridge detection balancing circuit, and the pair of planar spiral coils are respectively a detection coil and a reference coil, the detection coil and the reference coil are respectively divided by a resistance network to form a full-bridge circuit, and the detection coil and the reference coil are separately installed at both ends of the strip probe skeleton. When the change in the oxide film thickness of the nuclear fuel rod strip causes the imbalance of the coil impedance, the full-bridge detection balancing circuit outputs a differential voltage signal proportional to the change in the film thickness.

[0009] In some embodiments, the temperature sensing unit is a PT1000 type platinum resistance temperature sensor.

[0010] In some embodiments, the probe support includes a connecting rod, a support body, and a flexible cantilever structure, the flexible cantilever structure is installed on the support body, and both ends of the connecting rod are respectively connected to the flexible cantilever structure and the probe body.

[0011] In some embodiments, one end of the connecting rod is threadedly connected to the flexible cantilever structure, and the other end of the connecting rod is threadedly connected to the probe body.

[0012] In some embodiments, the manufacturing material of the flexible cantilever structure is 304 stainless steel alloy.

[0013] In some embodiments, the inclination sensing unit is a BF350 full-bridge strain gauge which is pasted on a stress concentration area of the flexible cantilever structure in a bridge manner.

[0014] In some embodiments, the compact multifunctional integrated nuclear fuel rod strip detection probe further comprises a cable, an outer layer of the cable being wrapped with a shielding layer, the cable being used for transmitting detection signals of the eddy current detection unit, temperature signals of the temperature sensing unit and inclination signals of the inclination sensing unit, and a terminal end of the cable being reserved with a joint for connecting with an external detection instrument.

[0015] The implementation of the present application has the following beneficial effects: the compact multifunctional integrated nuclear fuel rod strip detection probe integrates the eddy current detection unit and the temperature sensing unit in the probe body, and realizes the multi-parameter collaborative work of the oxide film thickness detection, temperature compensation and attitude monitoring by setting the temperature sensing unit, solves the technical problems of low oxide film thickness detection precision, poor stability and weak environmental adaptability caused by temperature drift and probe attitude deviation in the prior art, and can realize in-situ, online and high-precision detection of the nuclear fuel rod cladding strip in a narrow space and an automatic detection environment, thereby significantly improving the intelligent level and engineering practicability of the detection system. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the present application, the present application will be further described below in combination with the drawings and embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor. In the drawings: Figure 1 is a general structure schematic diagram of the compact multifunctional integrated nuclear fuel rod strip detection probe in some embodiments of the present application; Figure 2 is a structure schematic diagram of the probe body in some embodiments of the present application; Figure 3 is a structure schematic diagram of the strip probe skeleton in some embodiments of the present application; Figure 4 is a detection principle schematic diagram of the compact multifunctional integrated nuclear fuel rod strip detection probe in some embodiments of the present application. DETAILED DESCRIPTION

[0017] In order to have a clearer understanding of the technical features, objectives and effects of the present application, the specific embodiments of the present application will now be described in detail with reference to the drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "upper", "lower", "left", "right", "vertical", "horizontal", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail" and the like are based on the directions or positional relationships shown in the drawings, constructed and operated in a particular direction, and are only for the convenience of describing the technical solutions, and do not indicate that the devices or elements referred to must have a particular direction, therefore, it cannot be understood as a limitation on the present application.

[0018] It should also be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing", "setting" and the like should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements or the interaction relationship between two elements. When an element is referred to as "on" or "below" another element, the element can be "directly" or "indirectly" above the other element, or there can be one or more intervening elements. The terms "first", "second", "third" and the like are only for the convenience of describing the technical solutions, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features, therefore, the features with "first", "second", "third" and the like can be explicitly or implicitly included one or more of the features. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0019] Please refer to Figures 1 to 4 , which is a compact multifunctional integrated nuclear fuel rod strip detection probe in some embodiments of the present application, which comprises a probe body 1, a probe support 2, an eddy current detection unit 3, a temperature sensing unit 4 and an inclination sensing unit. The probe body 1 is connected to the probe support 2, the eddy current detection unit 3 is integrated in the probe body 1, the eddy current detection unit 3 is used for collecting the eddy current response signal of the surface of the nuclear fuel rod strip and inverting the oxide film thickness; the temperature sensing unit 4 is integrated in the probe body 1 and is arranged adjacent to the eddy current detection unit 3, which is used for real-time acquisition of the working environment temperature of the eddy current detection unit 3, and provides a reference for temperature drift compensation of the eddy current detection signal; the inclination sensing unit is integrated on the probe support 2, which is used for monitoring the attitude change of the probe body 1 during detection, and outputs an attitude compensation signal.

[0020] It can be understood that the compact multifunctional integrated nuclear fuel rod strip detection probe realizes the multi-parameter cooperative work of the oxide film thickness detection, temperature compensation and posture monitoring by integrating the eddy current detection unit 3 and the temperature sensing unit 4 in the probe main body 1, and by setting the temperature sensing unit 4, solves the technical problems of low oxide film thickness detection precision, poor stability and weak environmental adaptability caused by temperature drift and probe posture offset in the prior art, and can realize in-situ, online and high-precision detection of the nuclear fuel rod cladding strip in a narrow space and an automatic detection environment, significantly improving the intelligent level and engineering practicability of the detection system.

[0021] As shown in Figure 2 and Figure 3 , the probe main body 1 includes a probe shell 11 and a strip probe skeleton 12 installed in the probe shell 11, and the eddy current detection unit 3 is installed at both ends of the strip probe skeleton 12, and the strip probe skeleton 12 is provided with a positioning groove for installing the temperature sensing unit 4. By installing the eddy current detection unit 3 at both ends of the strip probe skeleton 12 and the temperature sensing unit 4 in the middle positioning groove, the orderly integration of the eddy current detection unit 3 and the temperature sensing unit 4 is realized, the installation stability and working reliability of each unit are ensured, and a good structural foundation is also provided for subsequent signal acquisition and processing.

[0022] The probe main body 1 further includes a top end shell 13 and an aluminum oxide film, the top end shell 13 is connected to the probe shell 11, the aluminum oxide film is located between the top end shell 13 and the strip probe skeleton 12, and the internal gap of the probe shell 11 is sealed with sealing glue. The setting of the top end shell 13, the aluminum oxide film and the sealing glue plays an effective protection role for the eddy current detection unit 3 and the temperature sensing unit 4 inside the probe main body 1, which can prevent the interference and damage of the external environment to the internal elements and improve the service life and working stability of the probe main body 1. Specifically, the threaded top end shell 13 is connected to the probe main body 1, and then the aluminum oxide film is used for capping, after capping, the inside of the top end shell 13 is sealed with sealing glue, to ensure the normal work of the probe main body 1 under water. In addition, the probe main body 1 is designed as a whole cylinder, the overall size is compact, the diameter is 7mm and the length is 20mm, which meets the detection requirements in a narrow space. The probe shell 11 is made of 304 stainless steel material to ensure the structural strength and corrosion resistance of the probe main body 1.

[0023] The eddy current detection unit 3 includes a pair of planar spiral coils with completely symmetrical geometric parameters and a full-bridge detection balancing circuit. The pair of planar spiral coils are respectively a detection coil 31 and a reference coil 32. The detection coil 31 and the reference coil 32 respectively form a full-bridge circuit with a resistance network voltage division. The detection coil 31 and the reference coil 32 are separately installed at two ends of the strip probe skeleton 12. When the thickness of the oxide film of the nuclear fuel rod strip changes and causes the imbalance of the coil impedance, the full-bridge detection balancing circuit outputs a differential voltage signal proportional to the film thickness change. Understandably, the eddy current detection unit 3 adopts the differential coil with completely symmetrical geometric parameters and the full-bridge detection balancing circuit, which is used for high-sensitivity and high-anti-interference collection of the eddy current response signal of the surface of the nuclear fuel rod strip, and realizes accurate inversion of the oxide film thickness. When the thickness of the oxide film of the strip changes and causes the imbalance of the coil impedance, the full-bridge detection balancing circuit outputs a differential voltage signal proportional to the film thickness change. The use of the differential coil and the full-bridge structure can effectively suppress common-mode noise such as environmental electromagnetic interference, temperature drift and lift-off fluctuation, significantly improve the signal-to-noise ratio, and thus realize high-precision detection of the oxide film thickness. As shown in Figure 4 The working principle of the eddy current detection unit 3 is as follows: the detection coil 31 and the reference coil 32 are subjected to resistance voltage division, and then a differential signal is sent to a high-speed signal acquisition system 71. At the same time, the high-speed signal acquisition system 71 also acquires a temperature sensor signal. The high-speed signal acquisition system 71 sends the signals of the two to an upper computer 72, so that the upper computer 72 performs real-time temperature compensation on the signals through an algorithm, and has good real-time performance.

[0024] Preferably, the temperature sensing unit 4 is a PT1000 type platinum resistance temperature sensor. The PT1000 type platinum resistance temperature sensor has the advantages of high measurement accuracy, good stability and fast response speed, and can accurately and timely acquire the working environment temperature of the eddy current detection unit 3, thereby providing a reliable reference for temperature drift compensation of the eddy current detection signal and ensuring the accuracy of the detection result of the oxide film thickness. More specifically, in order to solve the problem of material conductivity drift of the eddy current detection signal caused by temperature fluctuation, the PT1000 type platinum resistance temperature sensor is integrated in situ in the physical proximity of the detection coil 31. The PT1000 type platinum resistance temperature sensor is placed in the positioning groove position of the strip probe skeleton 12, so as to realize real-time, co-thermal field and high-precision monitoring of the working temperature of the detection coil 31, and provide an accurate temperature reference for subsequent online temperature drift compensation. The "coil-adjacent" temperature monitoring structure can eliminate the heat conduction delay and spatial temperature difference error compared with the traditional external or support distal temperature measurement scheme, and is suitable for high-sensitivity detection scenarios.

[0025] As shown in Figure 1 and Figure 2As shown, the probe support 2 comprises a connecting rod 21, a support body 22, and a flexible cantilever structure 23 mounted on the support body 22, and two ends of the connecting rod 21 are connected to the flexible cantilever structure 23 and the probe body 1 respectively. The flexible cantilever structure 23 is a functional section of the probe support 2 cooperating with the connecting rod 21, which is essentially an integrated metal member with controllable elastic deformation capability and rigid support characteristics. By bending and deforming itself, the posture changes (such as pitch angle and roll angle deviation) of the probe body 1 during detection are converted into measurable mechanical strain, providing a physical basis for the installation of the inclination sensing unit. By connecting the flexible cantilever structure 23 and the probe body 1 through the connecting rod 21, the probe body 1 is quickly installed and disassembled, and at the same time, the installation and work of the inclination sensing unit are also provided with good structural support, improving the convenience and structural stability of the probe. In this embodiment, one end of the connecting rod 21 is threadedly connected with the flexible cantilever structure 23, and the other end of the connecting rod 21 is threadedly connected with the probe body 1. Threaded connection has the advantages of reliable connection and convenient disassembly, which is convenient for assembly, maintenance and replacement between components, and at the same time, ensures the connection strength and coaxiality between components, avoiding measurement errors caused by vibration or impact.

[0026] Preferably, the manufacturing material of the flexible cantilever structure 23 is 304 stainless steel alloy, which has good elastic recovery and fatigue resistance, and can realize controllable elastic deformation while ensuring structural strength, providing a reliable mechanical carrier for the work of the inclination sensing unit and ensuring the accuracy and stability of the posture monitoring.

[0027] Preferably, the inclination sensing unit is a BF350 full-bridge strain gauge, which is pasted on the stress concentration area of the flexible cantilever structure 23 in a bridge mode. To solve the problem of lift-off fluctuation and coupling efficiency reduction caused by probe posture deviation, the inclination sensing unit of the present application adopts a BF350 full-bridge strain gauge, which is pasted on the stress concentration area of the flexible cantilever structure 23, and can accurately convert the mechanical strain of the flexible cantilever structure 23 into resistance change, thereby outputting a voltage signal proportional to the change of the probe posture, and realizing high-precision monitoring of the probe body 1 posture, providing a reliable basis for posture compensation of the detection result. More specifically, when the probe body 1 changes in inclination (such as the pitch angle θ) due to installation deviation, vibration or surface undulation of the strip, the flexible cantilever structure 23 deforms in bending, causing the surface strain distribution to change; the BF350 full-bridge strain gauge is pasted on the stress concentration area of the elastic sheet in a bridge mode, converting the mechanical strain into resistance change, and further outputting a voltage signal proportional to the inclination θ; the inclination signal is amplified and conditioned, and then input into the data acquisition system synchronously with the eddy current signal, for compensating the inclination in different states. In addition, the BF350 full-bridge strain gauge is pasted on the surface of the flexible cantilever structure 23 by glue, ensuring that it can maintain good adhesion under high vibration. The leads of the BF350 full-bridge strain gauge can be connected to the signal acquisition module through thin wires, and the real-time monitoring of the probe body 1 posture is realized by directly arranging the BF350 full-bridge strain gauge in the stress concentration area, further enhancing the robustness and reliability of the system.

[0028] The compact multifunctional integrated nuclear fuel rod strip detection probe further comprises a cable, the outer layer of the cable is wrapped with a shielding layer, the cable is used for transmitting the detection signal of the eddy current detection unit 3, the temperature signal of the temperature sensing unit 4 and the inclination signal of the inclination sensing unit, and a connector for connecting with an external detection instrument is reserved at the end of the cable. The setting of the cable realizes the centralized transmission of the signals of the units, the shielding layer on the outer layer can effectively suppress external electromagnetic interference, ensuring the stability and accuracy of the signal transmission, and the connector reserved at the end for connecting with the external detection instrument facilitates the connection between the probe and the external detection equipment, improving the use convenience and compatibility of the probe.

[0029] The working principle of the present application is as follows: when the nuclear fuel rod strip is detected, the detection coil 31 in the eddy current detection unit 3 is close to the surface of the nuclear fuel rod strip, and the eddy current response signal is collected. When the thickness of the oxide film of the nuclear fuel rod strip changes, the impedance of the detection coil 31 changes, the full-bridge detection balance circuit outputs a differential voltage signal, and the thickness of the oxide film is obtained by processing the differential voltage signal.

[0030] At the same time, the temperature sensing unit 4 collects the working environment temperature of the eddy current detection unit 3 in real time, and transmits the temperature signal to the external data processing system, for temperature drift compensation of the temperature signal.

[0031] The tilt sensing unit is attached to the stress concentration area of ​​the flexible cantilever structure 23. When the probe body 1 changes its posture during the detection process, it will bend and deform, causing the resistance of the tilt sensing unit to change. It outputs a voltage signal proportional to the posture change, which is transmitted to the external data processing system for posture compensation of the detection results.

[0032] The cable transmits the detection signal from the eddy current detection unit 3, the temperature signal from the temperature sensing unit 4, and the tilt angle signal from the tilt angle sensing unit to external detection instruments, enabling centralized processing and analysis of the detection data.

[0033] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A compact multi-functional integrated nuclear fuel rod strip inspection probe, characterized by, The probe body (1) is connected to the probe support (2), the eddy current detection unit (3) is integrated in the probe body (1), and the eddy current detection unit (3) is used for collecting the eddy current response signal of the nuclear fuel rod strip surface and inverting the oxide film thickness. The temperature sensing unit (4) is integrated in the probe body (1) and is arranged adjacent to the eddy current detection unit (3), which is used for collecting the working environment temperature of the eddy current detection unit (3) in real time, and providing a reference for temperature drift compensation of the eddy current detection signal. The inclination sensing unit is integrated on the probe support (2), which is used for monitoring the attitude change of the probe body (1) during detection, and outputting an attitude compensation signal. The probe body (1) includes a probe shell (11) and a strip probe skeleton (12) installed in the probe shell (11), and the strip probe skeleton (12) is provided with a positioning groove for installing the temperature sensing unit (4).

2. The compact multi-functional integrated nuclear fuel rod strip inspection probe of claim 1, wherein, The probe body (1) further includes a top shell (13) and an alumina film, the top shell (13) is connected to the probe shell (11), the alumina film is located between the top shell (13) and the strip probe skeleton (12), and the internal gap of the probe shell (11) is sealed with sealing glue.

3. The compact multi-functional integrated nuclear fuel rod strip inspection probe of claim 2, wherein, The eddy current detection unit (3) includes a pair of planar spiral coils with completely symmetrical geometric parameters and a full-bridge detection balance circuit, and a pair of planar spiral coils are respectively a detection coil (31) and a reference coil (32).

4. The compact multi-functional integrated nuclear fuel rod strip inspection probe of claim 2, wherein, When the coil impedance is unbalanced due to the change of the oxide film thickness of the nuclear fuel rod strip, the full-bridge detection balance circuit outputs a differential voltage signal proportional to the film thickness change. The temperature sensing unit (4) is a PT1000 type platinum resistance temperature sensor.

5. The compact multi-functional integrated nuclear fuel rod strip inspection probe of claim 1, wherein, The probe support (2) includes a connecting rod (21), a support body (22) and a flexible cantilever structure (23), the flexible cantilever structure (23) is installed on the support body (22), and the two ends of the connecting rod (21) are respectively connected to the flexible cantilever structure (23) and the probe body (1).

6. The compact multi-functional integrated nuclear fuel rod strip inspection probe of claim 1, wherein, One end of the connecting rod (21) is threadedly connected with the flexible cantilever structure (23), and the other end of the connecting rod (21) is threadedly connected with the probe body (1).

7. The compact, multifunctional integrated fuel rod strip detection probe of claim 6, wherein, The manufacturing material of the flexible cantilever structure (23) is 304 stainless steel alloy.

8. The compact, multi-functional integrated nuclear fuel rod strip inspection probe of claim 6, wherein, The inclination sensing unit is a BF350 full-bridge strain gauge, which is pasted on the stress concentration area of the flexible cantilever structure (23) in the form of a bridge.

9. The compact, multifunctional integrated fuel rod strip detection probe of claim 6, wherein, ​ 10. The compact, multifunctional integrated nuclear fuel rod strip inspection probe of claim 1, wherein, The compact multifunctional integrated nuclear fuel rod strip detection probe further comprises a cable, an outer layer of the cable is wrapped with a shielding layer, the cable is used for transmitting detection signals of the eddy current detection unit (3), temperature signals of the temperature sensing unit (4) and inclination signals of the inclination sensing unit, and a joint connected with an external detection instrument is reserved at an end of the cable.

Images