Plate-type probe for rapidly detecting defects of steel lining of containment vessel

Abstract

The utility model relates to the technical field of containment steel lining defect detection, aims to solve the technical problem that ultrasonic guided excitation multi-mode is difficult to determine, and provides a plate-type probe for rapidly detecting containment steel lining defects, which comprises a plate-type magnetostriction sheet, two plate-type permanent magnets are mounted on the plate-type magnetostriction sheet, and the two plate-type permanent magnets are mounted on the plate-type magnetostriction sheet. A comb-shaped coil support is installed between the two plate type permanent magnets, a set of supporting plates arranged at intervals are arranged in the comb-shaped coil support, and each supporting plate is evenly wound with a conductive spiral coil array. The plate-type probe has good modal selectivity, can effectively excite SH0 waves in a steel lining plate, and can realize remote detection of an unreachable area of a containment steel lining.

Description

Technical Field

[0001] The utility model relates to the technical field of defect detection of steel liners of containments, in particular to a plate probe for rapid detection of defects in steel liners of containments. Background Art

[0002] The containment structure is the last barrier for radiation protection in nuclear power plants, and its structural integrity must be ensured throughout its service life. The corrosion risk areas of the steel liner belong to the areas that are inaccessible for daily visual inspection in the power plant, and the existing detection means are limited. The experience feedback of steel liner corrosion and perforation that has occurred indicates that it is urgent to develop corrosion detection technologies for inaccessible areas of steel liners and to master the aging degradation of inaccessible areas of steel liners in advance.

[0003] At present, the self-focusing phased array ultrasonic detection technology can effectively identify various defects such as pores with an equivalent diameter of more than 0.5 mm, lack of fusion, and cracks, with a signal-to-noise ratio of more than 12 dB, and can realize rapid automatic ultrasonic inspection of steel liner welds. However, no corresponding research has been carried out on the inaccessible areas of the steel liner of the containment itself. The ultrasonic guided wave technology installs probes at accessible positions to detect inaccessible areas at a long distance, which is the most likely technical means to realize rapid detection of inaccessible areas. At present, the US EPRI has carried out experimental research on the detection of steel liner corrosion defects, and the research shows that the ultrasonic guided wave technology can be effectively used for the detection of defects in inaccessible areas of steel liners.

[0004] When a ferromagnetic crystal is magnetized in an external magnetic field, the phenomenon that its size and volume change is called magnetostriction or magneto-optical effect. Based on the magnetostrictive effect, guided waves are excited on the magnetostrictive tape, and the guided waves are transmitted from the magnetostrictive tape to the component to be measured through dry coupling or adhesive coupling to realize guided wave excitation; and the guided waves are transmitted back from the component to be measured to the magnetostrictive tape through the same coupling method, and based on the inverse magnetostrictive effect, guided wave reception is realized, and magnetostrictive ultrasonic guided wave defect detection can be indirectly realized.

[0005] The propagation characteristics of ultrasonic guided waves (such as dispersion, multimodality, and attenuation, etc.) are directly related to their detection effects. Due to the non-dispersive characteristics of the low-order horizontal shear wave (SH wave) during the propagation process in the plate structure, the SH wave has certain advantages for non-destructive testing of the plate structure. Summary of the Utility Model

[0006] The purpose of the utility model is to provide a plate probe for rapid detection of defects in steel liners of containments, which solves the problem of difficult determination of multimodal ultrasonic excitation. The plate probe has good modal selectivity and can effectively excite SH waves in the steel liner plate, and can realize long-distance detection of inaccessible areas of steel liners of containments. 0 Waves, and can realize long-distance detection of inaccessible areas of steel liners of containments.

[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0008] A plate-type probe for rapid detection of defects in the steel lining of a containment vessel, comprising a plate-type magnetostrictive sheet, on which two plate-type permanent magnets are mounted. A comb-shaped coil holder is mounted between the two plate-type permanent magnets. A group of spaced-apart support plates is provided inside the comb-shaped coil holder, and a conductive spiral coil array is evenly wound on each support plate.

[0009] In some embodiments, the number of the support plates is 5 and they are evenly arranged.

[0010] In some embodiments, the outside of the comb-shaped coil holder is of a C-shaped structure.

[0011] In some embodiments, the two plate-type permanent magnets have the same structure and are symmetrically arranged.

[0012] In some embodiments, the plate-type permanent magnet is in the shape of a thin plate.

[0013] In some embodiments, the two plate-type permanent magnets are respectively fixed on both sides of the long side of the plate-type magnetostrictive sheet.

[0014] In some embodiments, the comb-shaped coil holder is arranged at the middle position between the two plate-type permanent magnets.

[0015] In some embodiments, the plate-type magnetostrictive sheet is in the shape of a thin plate with dimensions of 80mm×40mm×3mm.

[0016] In some embodiments, the conductive spiral coil array has five spiral coils.

[0017] In some embodiments, the winding directions of the conductive spiral coil array are alternately clockwise and counterclockwise.

[0018] Compared with the prior art, the plate-type probe for rapid detection of defects in the steel lining of a containment vessel provided by the present utility model has the following beneficial effects:

[0019] By the interaction between the plate-type magnetostrictive sheet and the metal plate to be measured, under the action of two mutually perpendicular magnetic fields provided by the plate-type permanent magnet and the coil array, horizontal shear waves (SH waves) are effectively excited in the metal plate to be measured, solving the problem that the echo signals are difficult to interpret caused by the dispersion and multimodal propagation characteristics of ultrasonic guided waves, improving the accuracy of defect detection, and increasing the applicability and usability of the plate-type ultrasonic probe.

[0020] The present utility model has spatial directivity. When the excitation probe and the receiving probe are on the same straight line and in the same direction, the amplitude of the received signal of the receiving probe is the largest and the energy is the highest, having higher detection sensitivity.

[0021] The utility model is applicable to the detection of metal plate-like structures, with small volume and light weight. It can be designed according to the detection requirements. At the same time, as an integrated magnetization device, it does not require pre-magnetization in advance, has simple operation, and is convenient for combined use of multiple probes on-site.

[0022] Furthermore, by designing the structural parameters and excitation frequency of the spiral coil, the utility model makes the distance between adjacent spiral coils equal to half of the wavelength of the guided wave mode to be excited, and the excitation frequency is the corresponding frequency of this wavelength, thus realizing the excitation of fixed-mode guided waves. Description of the Drawings

[0023] In order to more clearly illustrate the technical solution of the utility model, the drawings required in the technical description will be briefly introduced below.

[0024] Figure 1 It is a schematic structural diagram of the plate-type probe for rapid detection of defects in the steel lining of the containment vessel provided by the utility model;

[0025] Figure 2 It is a schematic internal structure diagram of the plate-type probe for rapid detection of defects in the steel lining of the containment vessel provided by the utility model;

[0026] Figure 3 It is a schematic diagram of the internal coil array of the plate-type probe for rapid detection of defects in the steel lining of the containment vessel provided by the utility model;

[0027] Figure 4 It is a schematic principle diagram of the plate-type probe for rapid detection of defects in the steel lining of the containment vessel provided by the utility model.

[0028] Description of the Reference Numerals:

[0029] 1. Plate-type permanent magnet; 2. Comb-shaped coil support; 3. Plate-type magnetostrictive sheet; 4. Conductive spiral coil array; 5. Plate-shaped component to be measured. Detailed Description of the Specific Embodiment

[0030] The following will be further described in detail through specific embodiments.

[0031] As Figure 1 and Figure 2 shown, the utility model provides a plate-type probe for rapid detection of defects in the steel lining of the containment vessel, including a plate-type permanent magnet 1, a comb-shaped coil support 2, a plate-type magnetostrictive sheet 3, and a conductive spiral coil array 4. This plate-type probe can be used for SH wave detection of metal plate structures.

[0032] The number of plate-shaped permanent magnets 1 is 2. The two plate-shaped permanent magnets 1 have the same structure and are symmetrically arranged on the plate-shaped magnetostrictive sheet 3. Among them, the plate-shaped permanent magnets 1 are arranged in a horizontal offset manner, with one side being the N pole and the other side being the S pole. The plate-shaped permanent magnet 1 is in an overall plate-shaped structure, such as a thin plate shape, with dimensions of 70mm×25mm×6mm.

[0033] As Figure 2 shown, the outside of the comb-shaped coil bracket 2 is in a "C" shape structure, and there are 5 support plates arranged inside it. The 5 support plates and the "C" shape structure together form the comb-shaped coil bracket structure, and each conductive spiral coil array 4 is evenly wound around the corresponding support plate. The support plate and the "C" shape structure are an integral whole. The support plate structure is mainly used to control the spacing D between adjacent coils to be equal to half the wavelength of the guided wave mode to be excited. It should be noted that the number of support plates can be selected and adjusted according to actual use, and the number can be set to odd or even. The more the number of support plates, the more coil arrays are wound, the greater the magnetic field strength, and the greater the sound field response at the target position.

[0034] Preferably, the 5 support plates are evenly spaced.

[0035] The plate-shaped magnetostrictive sheet 3 is perpendicularly and fixedly connected to the plate-shaped permanent magnet 1 and the comb-shaped coil bracket 2. The two plate-shaped permanent magnets 1 are respectively fixed on both sides of the long side of the plate-shaped magnetostrictive sheet 3. The comb-shaped coil bracket 2 is fixed in the middle of the plate-shaped magnetostrictive sheet 3 and is located between the two plate-shaped permanent magnets 1. The comb-shaped coil bracket 2 and the two plate-shaped permanent magnets 1 are arranged at intervals.

[0036] The plate-shaped magnetostrictive sheet 3 is in a thin plate shape. Preferably, the dimensions are 80mm×40mm×3mm.

[0037] As Figure 2 and Figure 3 shown, the spiral coil array 4 is composed of a single wire. The wire is wound around the comb-shaped coil bracket 2 from one end, wound clockwise from bottom to top on the support plate, then wound to the adjacent support plate, and wound counterclockwise from top to bottom on the adjacent support plate. It is wound alternately in this way, and a total of 5 groups of coil arrays are formed on the support plate. Finally, the wire is led out from the last support plate. The 5 groups of coil arrays are perpendicular to the plate-shaped permanent magnet 1, and both ends of the coil array are connected to the ultrasonic guided wave detection device. The plate-shaped magnetostrictive sheet 3 and the test plate 5 are coupled through a shear coupling agent.

[0038] The winding direction of the conductive spiral coil array 4 is clockwise and counterclockwise alternately. As Figure 3 shown, the alternate winding direction means that the winding directions of adjacent two conductive spiral coil arrays 4 are alternate. The wire has an inlet end and an outlet end, enters from the first bracket, and comes out from the last bracket. The coil is clockwise from bottom to top along the first bracket. When wound to the second bracket, it is counterclockwise from top to bottom, and so on.

[0039] During the guided wave excitation process, a high-frequency current is passed through the coil array to generate a dynamic magnetic field. Under the action of the static bias magnetic field provided by the plate-shaped permanent magnet 1 and the dynamic magnetic field generated by the conductive spiral coil array 4, the plate-shaped magnetostrictive sheet 3 excites guided waves due to the Wiedemann effect and is transmitted to the plate-shaped test sheet 5 through the shear coupling agent. The changing current signal in the energized coil array generates a dynamic magnetic field with the same changing law, causing the magnetostrictive sheet 3 to undergo torsional deformation with the same changing law.

[0040] In some embodiments, the plate-shaped permanent magnet 1 is a neodymium iron boron magnet with a surface magnetic field strength of not less than 3600 gauss; the comb-shaped coil bracket 2 is made of plexiglass; the plate-shaped magnetostrictive sheet 3 is made of a magneto-anisotropic Fe-Co alloy material, and a magnetostrictive coefficient of about 50 - 80 ppm can be obtained at a low magnetic field strength (50 - 100 Oe); the conductive spiral coil array 4 is composed of five spiral coils with a coil diameter of 0.5 mm - 1 mm, made of oxygen-free copper, with an insulating paint wrapped on the surface, and fixed to the comb-shaped coil bracket 2 with epoxy resin glue.

[0041] The conductive spiral coil array 4 is connected to the ultrasonic guided wave detection device to provide a dynamic magnetic field in the energized state. The plate-shaped permanent magnet 1 provides a static magnetic field for the plate-shaped magnetostrictive sheet 3. Under the action of two mutually perpendicular dynamic and static magnetic fields, the plate-shaped magnetostrictive sheet 3 deforms and excites a single-mode SH 0 wave.

[0042] The relationship between the spiral coil pitch and the wavelength is λ is the wavelength required for different frequency SH 0 mode excitation, f is the excitation frequency, and C s is the phase velocity of the SH 0 wave at this frequency. In the formula, D is the distance between adjacent spiral coils, and the distance between adjacent spiral coils can be determined according to the required fixed-mode guided wave excitation. The smaller the distance between adjacent spiral coils, the more concentrated the energy of the guided wave probe and the better the directivity.

[0043] For a 3-mm metal sheet, if 250 kHz is selected as the center frequency of the ultrasonic guided wave probe, at this time, the phase velocity of the SH 0 wave is 3130 m / s, then the center distance D between adjacent spiral coils should be designed to be 6.2 mm, and the ultrasonic wavelength of this mode is 12.4 mm.

[0044] The working principle of the present utility model is as follows:

[0045] As Figure 4 shown, the black arrow is the direction of the dynamic magnetic field, and the white arrow is the direction of wave transmission. is the direction of the static magnetic field. Under the combined action of the static magnetic field provided by the plate-shaped permanent magnet 1 and the dynamic magnetic field generated after the conductive spiral coil array 4 is energized, the plate-shaped magnetostrictive sheet 3 deforms due to the magnetostrictive effect. The guided wave is transmitted from the plate-shaped magnetostrictive sheet 3 to the plate-shaped component to be measured 5 by means of dry coupling or adhesive coupling.

[0046] When carrying out the defect detection of the steel lining of the containment vessel, the ultrasonic probe is used as both the excitation probe and the receiving probe. The ultrasonic probes are placed on the same straight line and in the same direction, and are coupled with the steel lining plate of the containment vessel through a coupling agent. An alternating current is passed through the bolt coil array, and then under the action of the dynamic magnetic field and the static magnetic field, the plate-shaped magnetostrictive sheet will excite SH 0 waves. By analyzing the receiving probe due to the inverse Wiedemann effect, the defect detection of the steel lining of the containment vessel can be realized.

[0047] The above are only specific embodiments 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 those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claimed rights.

Claims

1. A plate probe for rapid detection of containment steel lining defects, characterized in that: The invention comprises a plate-type magnetostrictive sheet (3), on which two plate-type permanent magnets (1) are mounted, a comb-shaped coil support (2) is mounted between the two plate-type permanent magnets (1), a group of support plates arranged at intervals are arranged inside the comb-shaped coil support (2), and a conductive spiral coil array (4) is evenly wound on each support plate.

2. The plate probe for rapid detection of containment steel lining defects according to claim 1 is characterized in that: The number of the support plates is 5 and they are evenly arranged.

3. The plate probe for rapid detection of containment steel lining defects according to claim 1 is characterized in that: The exterior of the comb-shaped coil support (2) is a U-shaped structure.

4. The plate probe for rapid detection of containment steel lining defects according to claim 1 is characterized in that: The two plate-type permanent magnets (1) have the same structure and are symmetrically arranged.

5. The plate probe for rapid detection of containment steel lining defects according to claim 4 is characterized in that: The plate-type permanent magnet (1) is in the shape of a thin plate.

6. The plate probe for rapid detection of containment steel lining defects according to claim 1 is characterized in that: The two plate-type permanent magnets (1) are respectively fixed on both sides of the long sides of the plate-type magnetostrictive sheet (3).

7. The plate-type probe for rapid detection of containment steel lining defects according to claim 1 or 6, characterized in that: The comb-shaped coil support (2) is arranged in the middle of the two plate-type permanent magnets (1).

8. The plate probe for rapid detection of containment steel lining defects according to claim 1 is characterized in that: The plate-type magnetostrictive sheet (3) is in the shape of a thin plate, with a size of 80 mm×40 mm×3 mm.

9. The plate probe for rapid detection of containment steel lining defects according to claim 1, characterized in that: The conductive spiral coil array (4) has five groups of spiral coils.

10. The plate probe for rapid detection of containment steel lining defects according to claim 1, characterized in that: The winding direction of the conductive spiral coil array (4) is alternating between clockwise and counterclockwise.

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