Sensor and measurement system for measuring foreign object between heat transfer tubes of steam generator of nuclear power plant

Abstract

A sensor for measuring a foreign object between heat transfer tubes of a steam generator of a nuclear power plant, comprising a probe assembly (1), a cable assembly (2) and a connecting assembly (3) which are connected successively; the probe assembly (1) comprises a housing (11), the end of the housing (11) away from the cable assembly (2) being provided with a camera module (12) and an illumination module (13), and the housing (11) being provided with an LIBS probe (14) used for emitting laser and receiving plasma spectra generated by exciting a substance; the connecting assembly (3) comprises an optical fiber connector (31) and a plurality of metal wire conductors (32) provided circumferentially around the optical fiber connector (31), the optical fiber connector (31) being used for coupling of an optical fiber bundle, and the metal wire conductors (32) being used for connecting to signal lines (23) and power supply wires (24). The sensor can perform, between heat transfer tubes of steam generators, three-dimensional imaging and precise dimensional measurement of foreign objects and in situ qualitative / quantitative analysis of element compositions of the foreign objects. Further provided is a measurement system for measuring a foreign object between heat transfer tubes of a steam generator of a nuclear power plant.

Description

Sensor and detection system for detecting foreign matter between heat transfer tubes of steam generators in nuclear power plants Technical Field

[0001] The present invention belongs to the technical field of in-situ non-destructive testing, and in particular relates to a sensor for detecting foreign matter between heat transfer tubes of a steam generator in a nuclear power plant and a detection system comprising the sensor. Background Art

[0002] Steam generators (evaporators) are core components of nuclear power plants, responsible for heat exchange between the primary and secondary circuits to generate steam for powering the turbines and providing a secondary radioactive barrier. Over long-term operation, foreign matter can accumulate within the steam generator due to external introduction and component aging (wear, corrosion, and fatigue). Although internal steam generator inspections and water flushing are performed during overhauls, some foreign matter may remain difficult to flush out or remove. This makes it difficult to accurately determine the foreign matter's three-dimensional dimensions and identify its composition or brand, further complicating the power plant's ability to trace the foreign matter and conduct safety assessments.

[0003] Currently, nuclear power plants typically use two methods to inspect and identify foreign objects within steam generators: 1) Using a specialized video probe inserted between the steam generator heat transfer tubes to inspect for foreign objects and determine their location and appearance; 2) Using XRF (X-ray fluorescence spectroscopy) to analyze the elemental composition of the removed foreign objects and determine their brand based on their component content. This method has significant limitations, primarily the inability to accurately determine the three-dimensional dimensions of foreign objects that cannot be removed, and the inability to rapidly measure their elemental composition in situ. Summary of the Invention

[0004] In view of this, in order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a sensor and detection system for detecting foreign objects between the heat transfer tubes of steam generators in nuclear power plants. The detection system with this sensor can realize three-dimensional imaging and precise size measurement of foreign objects between the heat transfer tubes of steam generators, and in-situ qualitative / quantitative analysis of the elemental composition of foreign objects, providing intuitive data for nuclear power plants to determine the location of foreign objects, clarify the shape of foreign objects, and judge the type of foreign objects.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] One objective of the present invention is to provide a sensor for detecting foreign objects between heat transfer tubes in steam generators of nuclear power plants. The sensor comprises a probe assembly, a cable assembly, and a connection assembly connected in sequence. The probe assembly includes a housing, an end of the housing remote from the cable assembly being provided with a camera module and an illumination module for collecting image information between the heat transfer tubes of the steam generator. The housing is provided with a LIBS (laser-induced breakdown spectroscopy) probe for emitting laser light and receiving a plasma spectrum generated by excited substances. The connection assembly comprises an optical fiber connector and a plurality of metal wire conductors arranged around the optical fiber connector. The optical fiber connector is used to couple optical fiber bundles, and the metal wire conductors are used to connect signal lines and power lines.

[0007] By combining the probe assembly, cable assembly, and connection assembly into an organic whole, it is convenient for on-site installation and use. The multiple camera modules installed on the probe assembly can image foreign objects between the steam generator heat transfer tubes at different angles. Combined with the image recognition algorithm, accurate three-dimensional measurement can be achieved. The LIBS probe emits an excitation laser to excite the substance to produce a plasma spectrum, which can realize the elemental composition detection of the foreign material. Therefore, the sensor can realize multiple functions such as in-situ three-dimensional imaging, size measurement, and elemental composition analysis of foreign objects between the steam generator heat transfer tubes.

[0008] According to some preferred embodiments of the present invention, the shell includes a first part and a second part symmetrically arranged on both sides of the first part, the first part is parallel to the second part, the first part and the second part are flush with one end of the cable assembly, a cavity is opened inside the first part for partially accommodating the LIBS probe, the central axis of the LIBS probe coincides with the central axis of the first part, and the two ends of the LIBS probe are respectively flush with the two ends of the first part.

[0009] According to some preferred embodiments of the present invention, the second part includes a first connecting block and a second connecting block connected to each other, the side of the first connecting block away from the second connecting block is connected to the side of the first part, the length of the first part is greater than the length of the first connecting block, and the end surface of the first part away from the cable assembly and the end surface of the first connecting block away from the cable assembly are both perpendicular to the central axis of the first part; the camera modules are symmetrically arranged, and the two camera modules are respectively located on the end surfaces of the two first connecting blocks away from the cable assembly. The two camera modules are respectively located on the upper and lower sides of the LIBS probe, and can observe the shape of foreign matter from different angles. Through the image recognition algorithm, the actual size of the foreign matter can be accurately calculated. The camera module is connected to the signal line and the power line to ensure the transmission of the video signal and the power supply of the camera module.

[0010] According to some preferred embodiments of the present invention, each of the second connecting blocks is provided with a first inclined surface and a second inclined surface at one end away from the cable assembly, the first inclined surface is close to the camera module, the lighting module is located on the first inclined surface, the camera module is mounted on the end face of the first portion away from the cable assembly, and the angle between the first inclined surface and the end face of the first portion away from the cable assembly is an obtuse angle. The lighting module is connected to a power supply wire and can provide a light source for the camera module. In some embodiments of the present invention, the lighting module is preferably an LED lamp, the brightness of each lighting module can be adjusted individually, the lighting module is mounted on the first inclined surface, the camera module is mounted on the end face of the first portion away from the cable assembly, and the angle between the first inclined surface and the end face of the first portion away from the cable assembly is an obtuse angle, which is conducive to concentrating the light and ensuring that the camera module obtains sufficient illumination.

[0011] According to some preferred implementation aspects of the present invention, the angle between the first inclined surface and an end surface of the first portion away from the cable assembly is 120-150°.

[0012] According to some preferred embodiments of the present invention, the length of the second connecting block is greater than that of the first connecting block, and a groove is formed between the first portion and the end of the second connecting block away from the cable assembly, with the camera module and the lighting module both located within the groove. The groove extends from one end of the probe assembly away from the cable assembly to the other end, and the camera module, disposed on the end surface of the first portion away from the cable assembly, and the lighting module, disposed on the first inclined surface, are both located within the groove. This ensures that the camera module and the lighting module are protected when the sensor moves between the heat transfer tubes of the steam generator, preventing damage to the camera module and the lighting module from colliding with foreign objects during operation.

[0013] According to some preferred embodiments of the present invention, the housing has a thickness of 0.5 to 2 mm and is made of stainless steel. In some embodiments of the present invention, the housing of the probe assembly is flat and 0.5 to 2 mm thick, enabling it to move freely within the narrow space between the heat transfer tubes of the steam generator. The housing is made of stainless steel.

[0014] According to some preferred embodiments of the present invention, the LIBS probe includes a sleeve and a collimating lens and a focusing lens located within the sleeve. The outer diameter of the sleeve is larger than the diameter of the cavity. The collimating lens is located adjacent to the cable assembly. The collimating lens is used to collimate the incident light from the optical fiber, and the focusing lens is used to focus the laser beam onto the surface of the foreign object between the heat transfer tubes of the steam generator. In some embodiments of the present invention, the outer diameter of the sleeve is larger than the diameter of the cavity, meaning that a portion of the outer wall of the sleeve of the LIBS probe is located outside the cavity of the first portion. The LIBS probe comprises an optical lens that can emit laser light and receive the plasma spectrum generated by the excited material, thereby enabling in-situ detection of the elemental composition of the foreign object. When the laser light is incident from the optical fiber port, it is collimated by the collimating lens and ultimately focused by the focusing lens onto the surface of the sample to be tested, thereby exciting the plasma spectrum of the sample surface material. Utilizing the reversibility of the optical path, the LIBS probe receives the spectrum and transmits it to the spectrum analyzer, thereby enabling elemental composition detection of the foreign object. Furthermore, the LIBS probe has an IP67 protection rating and can operate in relatively humid environments.

[0015] According to some preferred embodiments of the present invention, a fixing block is further included between the probe assembly and the cable assembly, one end of the fixing block being connected to an end of the probe assembly, and the other end of the fixing block being connected to an end of the cable assembly, and the fixing block being made of silicone. Using silicone as the fixing block ensures a greater bending radius at the connection between the probe assembly and the cable assembly, thereby reducing fatigue resistance.

[0016] According to some preferred embodiments of the present invention, the cable assembly includes a flat cable portion, a transfer line, and a transition portion, wherein the transition portion is used to connect the flat cable portion and the transfer line, and one end of the transfer line away from the transition portion is connected to the connecting assembly.

[0017] According to some preferred embodiments of the present invention, the flat ribbon cable portion includes a flat ribbon cable body, an optical fiber bundle, a plurality of signal lines and a power line arranged in parallel, the lengths of the optical fiber bundle, the signal line and the power line are all greater than the length of the flat ribbon cable body, and the flat ribbon cable body is provided with a first channel, a plurality of second channels and a plurality of third channels running through the flat ribbon cable body along its length direction, the second channel and the third channel are provided on both sides of the first channel, the first channel is used to accommodate the optical fiber bundle, the second channel is used to accommodate the signal line, and the third channel is used to accommodate the power line.

[0018] According to some preferred embodiments of the present invention, a plurality of drive slots are provided on one side of the flat ribbon cable body. The sensor further includes a drive mechanism that cooperates with the plurality of drive slots. The plurality of drive slots are evenly spaced along the length of the flat ribbon cable body. The drive mechanism is used to drive the probe assembly between the steam generator heat transfer tubes. The drive mechanism drives the flat ribbon cable portion, thereby driving the probe assembly to move between the steam generator heat transfer tubes. Furthermore, the flat ribbon cable body is extruded from PEEK (polyetheretherketone) material, which exhibits strong toughness and high-temperature resistance, enabling the probe assembly to move between the steam generator heat transfer tubes for detection.

[0019] According to some preferred embodiments of the present invention, one end of the optical fiber bundle is connected to the LIBS probe, and the signal line and the power line are distributed on both sides of the optical fiber bundle; the adapter cable includes a protective cover and an integrated fiber core located inside the protective cover, and the integrated fiber core includes an optical fiber and a plurality of metal fiber cores, and the plurality of metal fiber cores respectively correspond to the signal line and the power line inside the flat ribbon cable body, and the metal wire conductor in the connecting assembly; the optical fiber corresponds to the optical fiber bundle inside the flat ribbon cable body and the optical fiber connector in the connecting assembly. In some embodiments of the present invention, the adapter cable is a cylindrical flexible cable, and the protective cover is made of silicone material, which has good flexibility. In addition, during operation, the adapter cable is always located outside the steam generator.

[0020] According to some preferred embodiments of the present invention, the optical fiber bundle includes multiple first fiber cores and one second fiber core. Each first fiber core has a core diameter of 150-250 μm, and each second fiber core has a core diameter of 950-1100 μm. The first fiber cores are used to receive the laser-induced plasma spectrum, and the second fiber cores are used to transmit the excitation laser emitted by the laser. In some embodiments of the present invention, the optical fiber bundle contains seven fiber cores, six of which (the first fiber cores) have core diameters of 150-250 μm and are connected to the spectrometer of the detection host to receive the laser-induced plasma spectrum. The other fiber core is a high-energy specialty fiber (the second fiber core) with a core diameter of 950-1100 μm, which is used to transmit the excitation laser emitted by the laser. The signal line is a coaxial line for transmitting video signals, and the power line is used to power the LED light and camera.

[0021] According to some preferred embodiments of the present invention, the fixed block is provided with a first through hole, multiple second through holes and multiple third through holes running through the height direction thereof, the first through hole is used for the optical fiber bundle to pass through, the second through hole is used for the signal line to pass through, and the third through hole is used for the power wire to pass through; the signal line is used to transmit video signals, and the power wire is used to supply power to the lighting module and the camera module.

[0022] According to some preferred embodiments of the present invention, the connection assembly further includes an outer shell and an insulating filling body, the insulating filling body is located between the outer shell and the optical fiber connector, and the plurality of metal wire conductors are embedded in the insulating filling body. In some embodiments of the present invention, the outer shell of the connection assembly is made of stainless steel, which has high mechanical strength and corrosion resistance, and the interior of the outer shell is provided with a mechanical positioning bayonet, which can ensure accurate and rapid positioning between the needle and the hole when connected to the detection host. The insulator is made of PEEK material, which has good high temperature resistance, radiation resistance and insulation performance; the optical fiber connector is located in the middle of the outer shell of the connection assembly and is used to couple the optical fiber bundle. The connection assembly can ensure good interface coordination between the sensor and the detection host.

[0023] According to some preferred embodiments of the present invention, the connection assembly further includes a chip for identifying the probe assembly. The chip is connected to a metal wire conductor within the connection assembly, and the chip transmits signals to a detection host via the metal wire conductor. When the sensor is connected to the detection host, the detection host and detection software can use the chip to identify the type and technical information of the sensor's probe assembly, thereby facilitating the retrieval of detection software compatible with the corresponding type of probe assembly.

[0024] Another object of the present invention is to provide a detection system suitable for detecting foreign matter inside a steam generator of a nuclear power plant, which includes a detection host and the sensor as described above, wherein the sensor is connected to the detection host through the connecting component.

[0025] Due to the adoption of the above technical solution, compared with the existing technology, the benefits of the sensor and detection system suitable for detecting foreign objects inside the steam generator of a nuclear power plant of the present invention are: breaking through the limitation of the existing technology of nuclear power plants that requires the separate implementation of video inspection and composition detection of foreign objects between the heat transfer tubes of the steam generator. At the same time, it also solves the difficult problems of performing various in-situ non-destructive tests such as three-dimensional imaging and precise size measurement of foreign objects, in-situ qualitative / quantitative analysis of the elemental composition of foreign objects when foreign objects are stuck between the heat transfer tubes of the steam generator and cannot be removed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. 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 creative work.

[0027] FIG1 is a schematic diagram of the main structure of a sensor in a preferred embodiment of the present invention;

[0028] FIG2 is a schematic diagram of the three-dimensional structure of the probe assembly of the sensor in the preferred embodiment of the present invention;

[0029] FIG3 is a bottom view of the structure of the probe assembly of the sensor in the preferred embodiment of the present invention;

[0030] FIG4 is a schematic diagram of the three-dimensional structure of the LIBS probe of the sensor in a preferred embodiment of the present invention;

[0031] FIG5 is a schematic diagram of the front view of the structure of the sensor after the fixing block and transition portion are separated from the flat ribbon cable body in the preferred embodiment of the present invention;

[0032] FIG6 is a schematic top view of the structure of the connection assembly of the sensor in a preferred embodiment of the present invention;

[0033] Among them, the figure markings are: probe assembly-1, shell-11, first part-111, first connecting block-112, second connecting block-113, first inclined surface-1131, second inclined surface-1132, camera module-12, lighting module-13, LIBS probe-14, sleeve-141, collimating lens-142, focusing lens-143, cable assembly-2, flat cable body-21, drive groove-211, optical fiber bundle-22, signal line-23, power wire-24, adapter line-25, transition part-26, connecting assembly-3, optical fiber connector-31, metal wire conductor-32, shell-33, insulating filling body-34, fixing block-4. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0035] 1 to 6 , this embodiment provides a detection system for detecting foreign objects between heat transfer tubes of a steam generator in a nuclear power plant. The detection system includes a sensor and a detection host. The sensor includes a probe assembly 1, a fixing block 4, a cable assembly 2, and a connection assembly 3 connected in sequence. The connection assembly 3 is used to connect the sensor to the detection host.

[0036] Furthermore, as shown in Figures 1 to 4, the probe assembly 1 includes a housing 11, a LIBS probe 14, a camera module 12, and an illumination module 13 mounted on the housing 11. The camera module 12 is used to collect image information between the heat transfer tubes of the steam generator, the illumination module 13 is used to provide light for the camera module 12, and the LIBS probe 14 is used to emit laser light and receive the plasma spectrum generated by the excited material. The housing 11 is flat, 0.5 mm thick, and made of stainless steel. The housing 11 includes a first portion 111 and symmetrically arranged second portions located on either side of the first portion 111. The first portion 111 is parallel to the second portion and is flush with the end of the first portion 111 near the cable assembly 2. The interior of the first portion 111 defines a cavity for partially accommodating the LIBS probe 14. The central axis of the LIBS probe 14 coincides with the central axis of the first portion 111, and the ends of the LIBS probe 14 are flush with the ends of the first portion 111. The end surface of the first portion 111 facing away from the cable assembly 2 is perpendicular to the central axis of the first portion 111. In addition, the LIBS probe 14 is connected to the optical fiber bundle 22. The LIBS probe 14 includes a sleeve 141 and a collimating lens 142 and a focusing lens 143 located within the sleeve 141. Both the collimating lens 142 and the focusing lens 143 are perpendicular to the sleeve 141. The collimating lens 142 is located near the cable assembly 2. The collimating lens 142 is used to collimate the incident light from the optical fiber, and the focusing lens 143 is used to focus the laser spot on the surface of the foreign object between the heat transfer tubes of the steam generator. The outer diameter of the sleeve 141 is larger than the diameter of the cavity of the first part 111. That is, part of the outer wall of the sleeve 141 of the LIBS probe 14 is located outside the cavity of the first part 111, which facilitates the fixation of the LIBS probe 14. The LIBS probe 14 has an IP67 protection rating and can operate in relatively humid environments.

[0037] Specifically, the second portion includes a first connecting block 112 and a second connecting block 113. The side of the first connecting block 112 away from the second connecting block 113 is connected to the side of the first portion 111. The length of the first portion 111 is greater than that of the first connecting block 112, and the length of the second connecting block 113 is also greater than that of the first connecting block 112. This forms a groove between the ends of the first portion 111 and the second connecting block 113 away from the cable assembly 2. The groove is recessed from one end of the probe assembly 1 away from the cable assembly 2 to the other end. The end surface of the first connecting block 112 away from the cable assembly 2 is also perpendicular to the central axis of the first portion 111. In this embodiment, two camera modules 12 are symmetrically provided. The two camera modules 12 are respectively located on the end surfaces of the two first connecting blocks 112 away from the cable assembly 2. That is, the two camera modules 12 are respectively located on the upper and lower sides of the LIBS probe 14. This allows the appearance of foreign matter between the heat transfer tubes of the steam generator to be observed from different angles. The actual size of the foreign matter can be accurately calculated through the image recognition algorithm. The camera module 12 is connected to the signal line 23 and the power line 24 to ensure video signal transmission and power supply to the camera module 12. Furthermore, each second connecting block 113 has a first inclined surface 1131 and a second inclined surface 1132 on the end facing away from the cable assembly 2. The first inclined surface 1131 is located near the camera module 12. An illumination module 13 is disposed on the first inclined surface 1131 and connected to the power line 24 to provide light for the camera module 12. In this embodiment, the illumination modules 13 are preferably LED lights. Four illumination modules 13 are provided, with two illumination modules 13 located on each first inclined surface 1131. The spacing between the two illumination modules 13 on each first inclined surface 1131 is equal. The angle between the first inclined surface 1131 and the end of the first portion 111 facing away from the cable assembly 2 is between 120° and 150°. In this embodiment, the angle is preferably 135°, which helps focus light and ensures sufficient illumination for the camera module 12. In fact, the camera module 12 and the lighting module 13 are both located in the groove formed between the first part 111 and the second connecting block 113, which can ensure that the camera module 12 and the lighting module 13 are protected when the sensor shuttles between the heat transfer tubes of the steam generator, thereby avoiding the camera module 12 and the lighting module 13 from colliding with foreign objects and causing damage during operation.

[0038] Furthermore, as shown in Figures 1 and 5, the cable assembly 2 includes a flat ribbon cable portion, an adapter cable 25, and a transition portion 26. The transition portion 26 is used to connect the flat ribbon cable portion to the adapter cable 25. The adapter cable 25 is connected to the connector assembly 3 at its end away from the transition portion 26. As shown in Figure 5, the flat ribbon cable portion includes a flat ribbon cable body 21, an optical fiber bundle 22, multiple signal lines 23, and a power conductor 24. The signal lines 23 and power conductors 24 are both located on either side of the optical fiber bundle 22. The signal lines 23 are coaxial and are used to transmit video signals. The power conductors 24 are used to power the LED lights and camera. The flat ribbon cable body 21 is internally provided with a first channel, multiple second channels, and multiple third channels running along its length. Second channels and third channels are provided on either side of the first channel. The number of second channels is equal to the number of signal lines 23, and the number of third channels is equal to the number of power conductors 24. The first channel is used to accommodate the optical fiber bundle 22, the second channel is used to accommodate the signal lines 23, and the third channel is used to accommodate the power conductors 24. The lengths of the optical fiber bundle 22, signal line 23, and power line 24 are all greater than the length of the flat ribbon cable body 21. To ensure the connection between the LIBS probe 14 and the optical fiber bundle 22, between the camera module 12 and the signal line 23 and power line 24, and between the lighting module 13 and the power line 24, a first through hole, multiple second through holes, and multiple third through holes are provided inside the fixing block 4, extending through the fixing block 4 in its height direction. The number of second through holes is equal to the number of signal lines 23, and the number of third through holes is equal to the number of power lines 24. The first through hole is used for passing the optical fiber bundle 22, the second through hole is used for passing the signal line 23, and the third through hole is used for passing the power line 24. This ensures that the signal line 23 can transmit the video signal collected by the camera module 12, and the power line 24 can supply power to the lighting module 13 and the camera module 12.

[0039] To facilitate the sensor's movement between the steam generator's heat transfer tubes, a plurality of drive slots 211 are provided along one side of the flat ribbon cable body 21. These slots 211 are evenly spaced along the length of the flat ribbon cable body 21. These slots 211 cooperate with a drive mechanism, which drives the flat ribbon cable, thereby moving the probe assembly 1 between the steam generator's heat transfer tubes. To ensure a stable bending radius at the connection between the probe assembly 1 and the cable assembly 2 and reduce fatigue resistance at the connection, the fixing block 4 is constructed of soft silicone. In this embodiment, the flat ribbon cable body 21 is extruded from PEEK, which offers strong toughness and high-temperature resistance, enabling the probe assembly 1 to move between the steam generator's heat transfer tubes.

[0040] In this embodiment, the optical fiber bundle 22 contains seven fiber cores, including six first fiber cores and one second fiber core. The six first fiber cores have a core diameter of 200 μm and are connected to the spectrometer of the detection host for receiving the laser-induced plasma spectrum. The other second fiber core is a high-energy special optical fiber with a core diameter of 1000 μm, which is used to transmit the excitation laser emitted by the laser. In addition, the adapter cable 25 is a cylindrical flexible cable, which includes a protective sheath and an integrated fiber core located inside the protective sheath. The protective sheath is made of silicone material and has good flexibility. The internal integrated fiber core includes an optical fiber and multiple metal fiber cores. The signal line 23 and power line 24 in the flat ribbon cable body 21 near the adapter cable 25 pass through the transition portion 26 to connect to one end of the multiple metal fiber cores. The optical fiber bundle 22 in the flat ribbon cable body 21 near the adapter cable 25 passes through the transition portion 26 to connect to one end of the optical fiber. During operation, the adapter cable 25 is always located outside the steam generator.

[0041] Furthermore, as shown in FIG6 , the connection assembly 3 includes an optical fiber connector 31, a plurality of metal wire conductors 32 arranged around the optical fiber connector 31, an outer shell 33, and an insulating filler 34. The insulating filler 34 is located between the outer shell 33 and the optical fiber connector 31, and the plurality of metal wire conductors 32 are embedded in the insulating filler 34. The optical fiber connector 31 is located in the middle of the outer shell 33 of the connection assembly 3 and is used to couple the optical fiber bundle 22. The metal wire conductor 32 is used to connect the signal line 23 and the power line 24. Specifically, the outer shell 33 is made of stainless steel, which has high mechanical strength and corrosion resistance. The interior of the outer shell 33 is provided with a mechanical positioning bayonet, which can ensure accurate and rapid positioning between the needle and the hole when connected to the detection host. The insulator is made of PEEK, which has good high temperature resistance, radiation resistance and insulation performance. In this embodiment, the metal wire conductor 32 is a copper wire conductor, the signal line 23 is a copper wire, and the metal fiber core is a copper fiber core. The other end of the optical fiber with the integrated fiber core in the adapter cable 25 is connected to the optical fiber connector of the connecting component 3, and the other end of the metal fiber core of the integrated fiber core in the adapter cable 25 is connected to the metal wire conductor 32 of the connecting component 3, so that the adapter cable 25 connects the flat cable part and the connecting component 3 to ensure signal transmission and laser emission.

[0042] In this embodiment, a driving mechanism drives the flat ribbon cable body 21, thereby moving the probe assembly 1 between the steam generator heat transfer tubes. Using two camera modules 12 located on the second portion of the probe assembly 1 housing 11, three-dimensional imaging of foreign objects between the steam generator heat transfer tubes is performed at different angles. Combined with an image recognition algorithm, this enables precise three-dimensional measurement of foreign object size. After laser light enters the fiber port, it passes through the connector and cable assembly 2 to the probe assembly 1. It is collimated by the collimating lens 142 of the LIBS probe 14, and ultimately focused by the focusing lens 143 onto the foreign object surface, exciting the plasma spectrum of the sample surface material. Utilizing the reversibility of the optical path, the LIBS probe 14 receives the spectrum and transmits it to the spectrometer, thereby detecting the elemental composition of the foreign material.

[0043] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A sensor for detecting foreign matter between heat transfer tubes of a steam generator in a nuclear power plant, characterized in that: The invention comprises a probe assembly, a cable assembly and a connection assembly which are connected in sequence. The probe assembly comprises a shell. A camera module and a lighting module for collecting image information between the heat transfer tubes of the steam generator are arranged at one end of the shell away from the cable assembly. A LIBS probe is arranged on the shell. The LIBS probe is used to emit laser and receive the plasma spectrum generated by the excited substance. The connection assembly comprises an optical fiber connector and a plurality of metal wire conductors arranged around the optical fiber connector. The optical fiber connector is used to couple the optical fiber bundle. The metal wire conductor is used to connect the signal line and the power line.

2. The sensor according to claim 1, characterized in that The shell includes a first part and a second part symmetrically arranged on both sides of the first part, the first part is parallel to the second part, the first part and the second part are flush with one end close to the cable assembly, a cavity is opened inside the first part for partially accommodating the LIBS probe, the central axis of the LIBS probe coincides with the central axis of the first part, and the two ends of the LIBS probe are respectively flush with the two ends of the first part.

3. The sensor according to claim 2, characterized in that The second part includes a first connecting block and a second connecting block that are connected to each other, a side of the first connecting block away from the second connecting block is connected to the side of the first part, the length of the first part is greater than the length of the first connecting block, an end surface of the first part away from the cable assembly and an end surface of the first connecting block away from the cable assembly are both perpendicular to the central axis of the first part; two camera modules are symmetrically arranged, and the two camera modules are respectively located on one end surface of two first connecting blocks away from the cable assembly.

4. The sensor according to claim 3, characterized in that Each of the second connecting blocks is provided with a first slope and a second slope at one end away from the cable assembly, the first slope is close to the camera module, the lighting module is located on the first slope, the camera module is installed on the end surface of the first part away from the cable assembly, and the angle between the first slope and the end surface of the first part away from the cable assembly is an obtuse angle.

5. The sensor according to claim 4, characterized in that An included angle between the first inclined surface and an end surface of the first portion away from the cable assembly is 120-150°.

6. The sensor according to claim 4, characterized in that Two lighting modules are arranged on each of the first inclined surfaces, and the distance between the two lighting modules arranged on each of the first inclined surfaces is equal; the lighting module arranged at the upper end of one of the first inclined surfaces and the lighting module arranged at the upper end of another of the first inclined surfaces are located at the same horizontal height, and the lighting module arranged at the lower end of one of the first inclined surfaces and the lighting module arranged at the lower end of another of the first inclined surfaces are located at the same horizontal height.

7. The sensor according to claim 3, characterized in that The length of the second connecting block is greater than that of the first connecting block. A groove is formed between the first portion and the end of the second connecting block away from the cable assembly. The camera module and the lighting module are both located in the groove.

8. The sensor according to claim 1, characterized in that The thickness of the shell is 0.5-2 mm, and the shell is made of stainless steel.

9. The sensor according to claim 2, characterized in that The LIBS probe includes a sleeve and a collimating lens and a focusing lens located inside the sleeve. The outer diameter of the sleeve is greater than the diameter of the cavity. The collimating lens is close to the cable assembly. The collimating lens is used to collimate the incident light of the optical fiber. The focusing lens is used to focus the laser spot on the surface of the foreign object between the heat transfer tubes of the steam generator.

10. The sensor according to claim 1, characterized in that It also includes a fixing block located between the probe assembly and the cable assembly, one end of the fixing block is connected to the end of the probe assembly, and the other end of the fixing block is connected to the end of the cable assembly, and the material of the fixing block is silicone.

11. The sensor according to claim 10, characterized in that The cable assembly includes a flat cable portion, a transfer line and a transition portion, wherein the transition portion is used to connect the flat cable portion and the transfer line, and an end of the transfer line away from the transition portion is connected to the connection assembly.

12. The sensor according to claim 11, characterized in that The flat ribbon cable portion includes a flat ribbon cable body, an optical fiber bundle, a plurality of signal lines and a power line arranged in parallel, the lengths of the optical fiber bundle, the signal line and the power line are all greater than the length of the flat ribbon cable body, and the flat ribbon cable body is provided with a first channel, a plurality of second channels and a plurality of third channels running through the flat ribbon cable body along its length direction, the second channel and the third channel are provided on both sides of the first channel, the first channel is used to accommodate the optical fiber bundle, the second channel is used to accommodate the signal line, and the third channel is used to accommodate the power line.

13. The sensor according to claim 12, characterized in that A plurality of drive grooves are provided on one side of the flat ribbon cable body, and the sensor further comprises a drive mechanism cooperating with the plurality of drive grooves. The plurality of drive grooves are evenly spaced along the length direction of the flat ribbon cable body, and the drive mechanism is used to drive the probe assembly to move between the heat transfer tubes of the steam generator.

14. The sensor according to claim 12, characterized in that One end of the optical fiber bundle is connected to the LIBS probe, and the signal line and the power line are distributed on both sides of the optical fiber bundle; the adapter cable includes a protective cover and an integrated fiber core located inside the protective cover, and the integrated fiber core includes an optical fiber and multiple metal fiber cores, and the multiple metal fiber cores respectively correspond to the signal line and the power line inside the flat ribbon cable body, and the metal wire conductor in the connecting component; the optical fiber corresponds to the optical fiber bundle inside the flat ribbon cable body and the optical fiber connector in the connecting component.

15. The sensor according to claim 14, characterized in that The optical fiber bundle includes multiple first fiber cores and one second fiber core, the core diameter of each of the first fiber cores is 150-250 μm, the core diameter of the second fiber core is 950-1100 μm, the first fiber core is used to receive the laser induced plasma spectrum, and the second fiber core is used to transmit the excitation laser emitted by the laser.

16. The sensor according to claim 12, characterized in that The fixed block is provided with a first through hole, a plurality of second through holes and a plurality of third through holes running through the height direction thereof, the first through hole is used for the optical fiber bundle to pass through, the second through hole is used for the signal line to pass through, and the third through hole is used for the power line to pass through; the signal line is used to transmit video signals, and the power line is used to supply power to the lighting module and the camera module.

17. The sensor according to claim 1, characterized in that The connection assembly also includes a shell and an insulating filling body, wherein the insulating filling body is located between the shell and the optical fiber connector, and a plurality of metal wire conductors are embedded in the insulating filling body.

18. The sensor according to claim 1, characterized in that A chip for identifying the probe assembly is also provided in the connection assembly. The chip is connected to the metal wire conductor in the connection assembly. The chip transmits signals to the detection host through the metal wire conductor.

19. A detection system for detecting foreign matter between heat transfer tubes of steam generators in nuclear power plants, characterized in that: It comprises a detection host and a sensor as described in any one of claims 1 to 18, wherein the sensor is connected to the detection host through the connecting component.

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