System and method for measuring wear of inner surface of bell mouth of hot sleeve of control rod driving mechanism

Abstract

The invention discloses a control rod driving mechanism heat sleeve horn mouth inner surface wear measurement system and method. The control rod driving mechanism heat sleeve horn mouth inner surface wear measurement system comprises a multi-degree-of-freedom mechanical device and a laser scanning device. The multi-degree-of-freedom mechanical device is used for carrying the laser scanning device and sending the laser scanning device to the position below a horn mouth of a control rod driving mechanism heat sleeve; the laser scanning device is used for carrying out laser scanning on the inner surface of a horn mouth of the control rod driving mechanism heat casing pipe so as to obtain a three-dimensional model of the inner surface of the horn mouth. According to the control rod driving mechanism heat sleeve horn mouth inner surface wear measurement system, through cooperation of the multi-degree-of-freedom mechanical device and the laser scanning device, effective three-dimensional measurement is carried out on the control rod driving mechanism heat sleeve horn mouth inner surface wear condition, and the measurement result is accurate and reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of nondestructive testing, and in particular to a system and method for measuring the inner surface wear of a bell mouth of a thermal sleeve of a control rod drive mechanism. Background Art

[0002] The thermowell of the control rod drive mechanism of a nuclear reactor is a key component that plays a guiding role on the top cover of the reactor pressure vessel of a nuclear power plant. Due to the vibration of the water flow, the upper flange of the thermowell may wear and sink. In severe cases, the flange of the thermowell may be completely worn and fall off, which may bring nuclear safety hazards. At present, in order to slow down the sinking trend of the thermowell of the control rod drive mechanism, power plants at home and abroad install a metal ring pad between the bottom of the thermowell bell and the upper part of the control rod guide tube as a support. This measure can effectively support the thermowell of the control rod drive mechanism, but the contact position between the inner surface of the bell and the metal pad will be worn due to vibration. It is necessary to take feasible measures to measure the wear of the inner surface of the thermowell bell and track its wear changes regularly. The area where the bell of the thermowell of the control rod drive mechanism is located has a high radiation dose, and the staff cannot go there to manually measure the wear. The wear measurement of the inner surface of the thermowell bell must be completed through an automated equipment system.

[0003] The existing dimensional measurement technologies for the thermowell area of ​​the control rod drive mechanism mainly use two cameras with fixed position angles to shoot the same area and determine the size information of the target object based on the triangulation method; the other type mainly uses the distance measurement and angle measurement functions of the laser total station to determine the size information of the target object. The above two methods are suitable for macroscopic measurement of the thermowell area of ​​the control rod drive mechanism, such as structural changes (the amount of sinking of the bell mouth of a thermowell relative to other components), etc. The dimensional measurement accuracy is usually at the millimeter level, but does not meet the accuracy requirements for wear measurement, and is not suitable for three-dimensional measurement of the wear condition of the inner surface of the bell mouth of the thermowell of the control rod drive mechanism. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a control rod drive mechanism thermowell bell mouth inner surface wear measurement system and a rod drive mechanism thermowell bell mouth inner surface wear measurement method.

[0005] The technical solution adopted by the present invention to solve the technical problem is: to provide a control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system, including a multi-degree-of-freedom mechanical device and a laser scanning device;

[0006] The multi-degree-of-freedom mechanical device is used to carry the laser scanning device and send the laser scanning device to the bottom of the bell mouth of the thermal sleeve of the control rod drive mechanism; the laser scanning device is used to perform laser scanning on the inner surface of the bell mouth of the thermal sleeve to obtain a three-dimensional model of the inner surface of the bell mouth of the thermal sleeve.

[0007] In some embodiments, the multi-degree-of-freedom mechanical device includes a load base, a first robotic arm rotatably mounted on the load base, a second robotic arm rotatably mounted on the first robotic arm, and a third robotic arm rotatably mounted on the second robotic arm; the first robotic arm and the second robotic arm rotate on a horizontal plane, and the third robotic arm can rotate between a horizontal direction and a vertical direction relative to the second robotic arm; the laser scanning device is mounted on the end of the third robotic arm away from the second robotic arm.

[0008] In some embodiments, the multi-degree-of-freedom mechanical device further comprises a roller group installed below the load base; the roller group comprises at least two universal wheels and two directional wheels.

[0009] In some embodiments, the multi-degree-of-freedom mechanical device also includes a first rotation axis, a second rotation axis and a third rotation axis; the first end of the first robotic arm is mounted on the load base through the first rotation axis, the first end of the second robotic arm is mounted on the second end of the first robotic arm through the second rotation axis, and the third robotic arm is vertically arranged relative to the second robotic arm and is mounted on the second end of the second robotic arm through the third rotation axis.

[0010] In some embodiments, the third robotic arm is a retractable robotic arm.

[0011] In some embodiments, the third robotic arm is provided with a parallel lead screw and a linear slide rail, and the laser scanning device is fitted on the lead screw and can move back and forth along the linear slide rail through the rotation of the lead screw.

[0012] In some embodiments, the laser scanning device includes a connecting member, a circumferential rotation unit, a line laser transceiver unit, and a centering camera unit;

[0013] The circumferential rotation unit is installed on the third mechanical arm through the connecting member and can rotate relative to the third mechanical arm; the line laser transceiver unit and the centering camera unit are arranged on the circumferential rotation unit and can rotate with the circumferential rotation unit;

[0014] The line laser transceiver unit is used to send a laser line to the inner surface of the bell mouth of the thermal sleeve and receive the reflected laser signal; the centering camera unit is used to photograph the internal situation of the bell mouth of the thermal sleeve to obtain the coverage of the laser line on the inner surface of the bell mouth.

[0015] In some embodiments, the control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system further includes a control acquisition system, wherein the control acquisition system is connected to the multi-degree-of-freedom mechanical device to control the opening, closing and rotation mode of the multi-degree-of-freedom mechanical device;

[0016] The control and acquisition system is connected to the laser scanning device, receives the laser signal fed back by the laser scanning device, and generates a three-dimensional model according to the laser signal; when there are wear defects on the three-dimensional model, the control and acquisition system also measures the size of the wear defects on the three-dimensional model through a measurement module.

[0017] The present invention also provides a control rod drive mechanism thermo-sleeve bell mouth inner surface wear measurement method, using any of the above control rod drive mechanism thermo-sleeve bell mouth inner surface wear measurement system, the control rod drive mechanism thermo-sleeve bell mouth inner surface wear measurement method comprising the following steps:

[0018] S1. Pushing a multi-degree-of-freedom mechanical device equipped with a laser scanning device into the top cover of a nuclear reactor pressure vessel;

[0019] S2, controlling the multi-degree-of-freedom mechanical device to rotate until the laser scanning device is sent to the position directly below the bell mouth of the thermowell of the control rod driving mechanism on the top cover, and the axis of the laser scanning device is coincident or approximately coincident with the axis of the bell mouth of the thermowell;

[0020] S3, performing laser scanning on the inner surface of the bell mouth of the thermal sleeve by the laser scanning device, and sending the acquired laser signal to the control and acquisition system;

[0021] S4. The control and acquisition system generates a three-dimensional model of the inner surface of the bell mouth of the thermal sleeve according to the received laser signal; when there is a wear defect on the three-dimensional model, the measurement module measures the size of the wear defect on the three-dimensional model.

[0022] In some embodiments, in step S2, the relative position relationship between the axis of the laser scanning device and the axis of the bell mouth of the thermal sleeve is obtained through real-time shooting of the centering camera unit of the laser scanning device.

[0023] In some embodiments, step S2 further includes: lifting the laser scanning device by a third mechanical arm of the multi-degree-of-freedom mechanical device until the bell mouth of the thermal sleeve is within the effective working range of the laser scanning device.

[0024] The beneficial effects of the present invention are as follows: through the cooperation of the multi-degree-of-freedom mechanical device and the laser scanning device, effective three-dimensional measurement is performed on the wear condition of the inner surface of the bell mouth of the thermal sleeve of the control rod drive mechanism, and the measurement result is accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0026] Figure 1 1 is a schematic structural diagram of a control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system according to an embodiment of the present invention;

[0027] Figure 2 The present invention is a schematic structural diagram of a laser scanning device in a control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0029] The control rod drive mechanism thermal sleeve bell mouth inner surface wear measuring system of the present invention is used to detect the bell mouth surface on the control rod drive mechanism thermal sleeve to obtain its wear condition.

[0030] like Figure 1 As shown, a control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system according to an embodiment of the present invention may include a multi-degree-of-freedom mechanical device and a laser scanning device 50.

[0031] The multi-degree-of-freedom mechanical device is used to carry the laser scanning device 50, and the laser scanning device 50 is sent to the bottom of the bell mouth 110 of the thermowell 100 of the control rod drive mechanism. The laser scanning device 50 is used to perform laser scanning on the inner surface of the bell mouth 110 of the thermowell 100 to obtain a three-dimensional model of the inner surface of the bell mouth 110 of the thermowell 100, so that the wear defect of the inner surface of the bell mouth 110 can be obtained through the three-dimensional model. In the case of wear defects, the size of the wear defects can be further measured by the measurement module, and the size information of the wear defects can be accurately obtained.

[0032] The multi-degree-of-freedom mechanical device may further include a load base 1, a first mechanical arm 10, a second mechanical arm 20, and a third mechanical arm 30. The first mechanical arm 10 is rotatably mounted on the load base 1, and the rotation of the first mechanical arm 10 is rotation on a horizontal plane; the second mechanical arm 20 is rotatably mounted on the first mechanical arm 10, and can rotate on a horizontal plane relative to the first mechanical arm 10; the third mechanical arm 30 is rotatably mounted on the second mechanical arm 20, and the third mechanical arm 30 can rotate between a horizontal direction and a vertical direction relative to the second mechanical arm 20.

[0033] Specifically, the load base 1 is used to bear all the weight above it, including the weight of the first to third mechanical arms 10 to 30. In order to maintain the stability of the center of gravity of the entire multi-degree-of-freedom mechanical device, especially the stability after the first to third mechanical arms 10 to 30 are rotated and extended, the load base 1 has sufficient weight or a certain counterweight.

[0034] A roller set 40 is also provided below the load base 1, through which the entire multi-degree-of-freedom mechanical device can be moved, making it easy to transport and transfer. Optionally, the roller set 40 can include two universal wheels and two fixed wheels; the universal wheels are used to guide the load base 1 to rotate in all directions, and the fixed wheels assist in movement and facilitate positioning after movement.

[0035] The first mechanical arm 10 can drive the second mechanical arm 20 and the third mechanical arm 30 thereon to face in various directions by rotating on a horizontal plane relative to the load base 1. The first mechanical arm 10 has a first end and a second end opposite to each other in its length direction. Optionally, the first end of the first mechanical arm 10 is mounted on the load base 1 via a first rotating shaft 11, so that the first mechanical arm 10 can rotate with the first rotating shaft 11 as a rotating shaft. The first rotating shaft 11 can be set at the center of the load base 1, or at a position close to the center.

[0036] The second mechanical arm 20 can drive the third mechanical arm 30 thereon to face in all directions by rotating relative to the first mechanical arm 10 on a horizontal plane. The second mechanical arm 20 has a first end and a second end opposite to each other in its length direction. The first end of the second mechanical arm 20 can be mounted on the second end of the first mechanical arm 10 through the second rotating shaft 12, so that the second mechanical arm 20 can rotate with the second rotating shaft 12 as the rotating shaft. When the second mechanical arm 20 rotates until its second end is away from the first mechanical arm 10, the second mechanical arm 20 extends outward relative to the first mechanical arm 10, and its positive projection is outside the load base 1 and does not fall on the load base 1. Since the load base 1 has sufficient weight or counterweight, the second mechanical arm 20 can still maintain stability and balance. When the second mechanical arm 20 rotates until its second end is on the first mechanical arm 10, it forms a folded state with the first mechanical arm 10, and can be directly above the load base 1 with the first mechanical arm 10 to reduce the overall appearance size of the multi-degree-of-freedom mechanical device.

[0037] Preferably, the length of the second robotic arm 20 is equal to or smaller than the length of the first robotic arm 10 .

[0038] The third robotic arm 30 can rotate between the horizontal direction and the vertical direction relative to the second robotic arm 20, so that the third robotic arm 30 can be in an inclined state on the second robotic arm 20, or in a vertical state, to meet different vertical orientation requirements. Furthermore, the third robotic arm 30 is vertically arranged relative to the second robotic arm 20 and is installed on the second end of the second robotic arm 20 through the third rotating shaft 13. When not in use or after use, the third robotic arm 30 can be rotated to be placed horizontally on the second robotic arm 20 to form a folded state, and cooperate with the second robotic arm 20 to be folded onto the first robotic arm 10, which can minimize the overall appearance size of the entire multi-degree-of-freedom mechanical device.

[0039] The laser scanning device 50 is mounted on the end of the third robot arm 30 away from the second robot arm 20 and can be located at the highest point of the multi-degree-of-freedom mechanical device, and is used to approach the bell mouth 110 of the thermal sleeve 100 for laser scanning.

[0040] In order to send the laser scanning device 50 close to or away from the bell mouth 110 of the thermal sleeve 100, in some embodiments, the third robot arm 30 may be a retractable robot arm, which can send the laser scanning device 50 thereon to the bell mouth 110 by extending, and can take the laser scanning device 50 away from the bell mouth 110 by retracting. The retractable robot arm may be implemented by, but is not limited to, a cylinder.

[0041] In some embodiments, the third mechanical arm 30 may be provided with a lifting assembly to send the laser scanning device 50 close to or away from the bell mouth 110 of the thermal sleeve 100. The lifting assembly may include a lead screw and a linear slide rail that are arranged on the third mechanical arm 30 and are parallel to each other. The laser scanning device 50 is matched with the lead screw and can move back and forth along the linear slide rail through the rotation of the lead screw.

[0042] Combination Figure 1 and Figure 2 The laser scanning device 50 may further include a connecting piece 51, a circumferential rotating unit 52, a line laser transceiver unit 53 and a centering camera unit 54.

[0043] The circumferential rotation unit 52 is mounted on the third mechanical arm 30 through the connecting member 51, and can rotate (rotate circumferentially) relative to the third mechanical arm 30. The connecting member 51 can be implemented by a quick connector, which facilitates the rapid installation and detachment of the laser scanning device 50 on the third mechanical arm 30. The line laser transceiver unit 53 and the centering camera unit 54 are both arranged on the circumferential rotation unit 52, and can rotate with the circumferential rotation unit 52.

[0044] The circumferential rotating unit 52 is rotated by a direct drive motor, so that the rotation speed, rotation direction and rotation angle of the mounted line laser transceiver unit 53 and the centering camera unit 54 can be adjusted.

[0045] The line laser transceiver unit 53 is used to emit a laser line to the inner surface of the bell mouth 110 of the thermal sleeve 100 and receive the reflected laser signal. The line laser transceiver unit 53 is preferably arranged at the edge of the circumferential rotation unit 52, and is inclined relative to the axis of the circumferential rotation unit 52, so that the transceiver end of the line laser transceiver unit 53 faces the inner surface of the bell mouth 110, so that when the line laser transceiver unit 53 rotates around the axis with the circumferential rotation unit 52, the laser line emitted by the line laser transceiver unit 53 also circles around the inner surface of the bell mouth 110 and receives the reflected laser signal.

[0046] The centering camera unit 54 is used to photograph the internal situation of the bell mouth 110 of the thermowell 100 to obtain the coverage of the laser line on the inner surface of the bell mouth 110. In addition, the centering camera unit 54 can also obtain the relative position of the laser scanning device 50 and the bell mouth 110, and assist in sending the laser scanning device 50 to the bottom of the bell mouth 110. The centering camera unit 54 is preferably arranged on the end surface of the circumferential rotating unit 52 facing the bell mouth 110, with the viewing angle upward and coincident with the axis of the circumferential rotating unit 52, and has the functions of magnification and focusing. The staff can use the centering camera unit 54 to determine whether the rotation axis of the laser scanning device is consistent with the axis of the bell mouth 110 of the thermowell 100.

[0047] In addition, the centering camera unit 54 can also assist in the mechanical energy video inspection of the inner surface of the bell mouth 110, and can obtain the degree and approximate location of the wear defect, and compare and supplement it with the three-dimensional model.

[0048] In some embodiments, the control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system also includes a control acquisition system (not shown). The control acquisition system is connected to the multi-degree-of-freedom mechanical device to control the opening and closing and rotation mode of the multi-degree-of-freedom mechanical device. The rotation mode includes any rotation of the first mechanical arm 10 to the third mechanical arm 30 or simultaneous rotation, rotation angle, etc. The control acquisition system is connected to the laser scanning device 50, receives the laser signal fed back by the laser scanning device 50, and generates a three-dimensional model according to the laser signal; when there is a wear defect on the three-dimensional model, the control acquisition system also measures the size of the wear defect on the three-dimensional model through the measurement module. The measurement module includes measurement software integrated in the control acquisition system.

[0049] The method for using the control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system of the present invention is to realize the measurement of the control rod drive mechanism thermal sleeve bell mouth inner surface wear.

[0050] refer to Figure 1 to Figure 2 The control rod drive mechanism thermo-sleeve bell mouth inner surface wear measurement method based on the control rod drive mechanism thermo-sleeve bell mouth inner surface wear measurement system may include the following steps in one embodiment:

[0051] S0. After debugging the laser scanning device 50, it is mounted on the third robot arm 30 of the multi-degree-of-freedom mechanical device.

[0052] S1. Push the multi-degree-of-freedom mechanical device equipped with the laser scanning device 50 into the top cover of the nuclear reactor pressure vessel and position it on the ground inside the top cover.

[0053] S2. Control the multi-degree-of-freedom mechanical device to rotate until the laser scanning device 50 is sent to the top cover directly below the bell mouth 110 of the thermal sleeve 100 of the control rod drive mechanism, and the axis of the laser scanning device 50 is coincident or approximately coincident with the axis of the bell mouth 110 of the thermal sleeve 100.

[0054] In some embodiments, the relative position relationship between the axis of the laser scanning device 50 and the axis of the bell mouth of the thermal sleeve is obtained through real-time shooting of the centering camera unit 54 of the laser scanning device 50 .

[0055] Among them, the staff remotely controls the multi-degree-of-freedom mechanical device through the control and acquisition system and performs corresponding actions after it is started, including: rotating the third robot arm 30 to a vertical direction, observing through the environmental camera and the centering camera unit 54 inside the top cover, controlling the first robot arm 10 and the second robot arm 20 to rotate to the designated control rod drive mechanism thermal sleeve 100 directly below, and finely adjusting the first robot arm 10, the second robot arm 20 and the third robot arm 30 until the centering camera unit 54 of the laser scanning device 50 shows that the axis of the bell mouth 110 of the control rod drive mechanism thermal sleeve 100 coincides or approximately coincides with the axis of the circumferential rotation unit 52.

[0056] The inner surface of the bell mouth 110 of the thermal sleeve 100 is observed by aligning the camera unit 54 to preliminarily determine the wear condition.

[0057] In some embodiments, step S2 further includes: lifting the laser scanning device 50 by the third mechanical arm 30 of the multi-degree-of-freedom mechanical device until the bell mouth 110 of the thermal sleeve 100 is within the effective working range of the laser scanning device 50 .

[0058] S3. The staff starts the laser scanning device 50 through the control and acquisition system, performs laser scanning on the inner surface of the bell mouth 110 of the thermal sleeve 100 through the laser scanning device 50, and sends the acquired laser signal to the control and acquisition system.

[0059] The coverage of the line laser emitted by the line laser transceiver unit 53 of the laser scanning device 50 on the inner surface of the bell mouth 110 of the thermal sleeve 100 is also observed through the centering camera unit 54 .

[0060] After confirming that the line laser coverage meets the requirements, the control and acquisition system controls the circumferential rotation unit 52 to rotate, driving the line laser to rotate circumferentially around the axis of the bell mouth 110 (or the axis of the circumferential rotation unit 52) ​​to cover all inner surfaces of the bell mouth 110, and the line laser transceiver unit 53 synchronously receives the reflected line laser passing through the inner surface of the bell mouth 110, and the formed laser signal is transmitted to the control and acquisition system.

[0061] S4. The control acquisition system generates a three-dimensional model of the inner surface of the bell mouth 110 of the thermal sleeve 100 according to the received laser signal.

[0062] If there is a wear defect on the inner surface of the bell mouth 110 of the thermal sleeve 100, the wear defect will appear different from other smooth areas on the inner surface in the three-dimensional model. The measurement module is used to measure the size of the wear defect on the three-dimensional model to obtain the size information of the wear defect.

[0063] It can be understood that when it is necessary to measure the wear of the inner surfaces of the bell mouths of multiple or all control rod drive mechanism thermal sleeves on the top cover, the above steps are repeated. Figure 1 The measurement system shown in the figure successively scans the inner surface of the bell mouth of each control rod drive mechanism thermal sleeve with a laser, or through multiple Figure 1 The measurement system shown performs laser scanning on the inner surfaces of the bell mouths of multiple control rod drive mechanism thermal sleeves at the same time.

[0064] In summary, the control rod drive mechanism thermowell bell mouth inner surface wear measurement system and method of the present invention can achieve the purpose of accurate three-dimensional measurement of the wear condition of the inner surface of the thermowell bell mouth.

[0065] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system, characterized in that: Including multi-degree-of-freedom mechanical devices and laser scanning devices; The multi-degree-of-freedom mechanical device is used to carry the laser scanning device and send the laser scanning device to the bottom of the bell mouth of the thermal sleeve of the control rod drive mechanism; the laser scanning device is used to perform laser scanning on the inner surface of the bell mouth of the thermal sleeve to obtain a three-dimensional model of the inner surface of the bell mouth of the thermal sleeve.

2. The control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system according to claim 1, characterized in that: The multi-degree-of-freedom mechanical device includes a load base, a first robotic arm rotatably mounted on the load base, a second robotic arm rotatably mounted on the first robotic arm, and a third robotic arm rotatably mounted on the second robotic arm; the first robotic arm and the second robotic arm rotate on a horizontal plane, and the third robotic arm can rotate between a horizontal direction and a vertical direction relative to the second robotic arm; the laser scanning device is mounted on the end of the third robotic arm away from the second robotic arm.

3. The control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system according to claim 2, characterized in that: The multi-degree-of-freedom mechanical device also includes a roller group installed below the load base; the roller group includes at least two universal wheels and two directional wheels.

4. The control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system according to claim 2, characterized in that: The multi-degree-of-freedom mechanical device also includes a first rotation axis, a second rotation axis and a third rotation axis; the first end of the first mechanical arm is mounted on the load base through the first rotation axis, the first end of the second mechanical arm is mounted on the second end of the first mechanical arm through the second rotation axis, and the third mechanical arm is vertically arranged relative to the second mechanical arm and is mounted on the second end of the second mechanical arm through the third rotation axis.

5. The control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system according to claim 4, characterized in that: The third mechanical arm is a retractable mechanical arm.

6. The control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system according to claim 4, characterized in that: The third mechanical arm is provided with a parallel lead screw and a linear slide rail, and the laser scanning device is matched with the lead screw and can move back and forth along the linear slide rail through the rotation of the lead screw.

7. The control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system according to claim 2, characterized in that: The laser scanning device includes a connecting piece, a circumferential rotating unit, a line laser transceiver unit and a centering camera unit; The circumferential rotation unit is installed on the third mechanical arm through the connecting member and can rotate relative to the third mechanical arm; the line laser transceiver unit and the centering camera unit are arranged on the circumferential rotation unit and can rotate with the circumferential rotation unit; The line laser transceiver unit is used to send a laser line to the inner surface of the bell mouth of the thermal sleeve and receive the reflected laser signal; the centering camera unit is used to photograph the internal situation of the bell mouth of the thermal sleeve to obtain the coverage of the laser line on the inner surface of the bell mouth.

8. The control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system according to any one of claims 1 to 7, characterized in that: The control rod drive mechanism thermal sleeve bell mouth inner surface wear measurement system further includes a control acquisition system, which is connected to the multi-degree-of-freedom mechanical device to control the opening, closing and rotation mode of the multi-degree-of-freedom mechanical device; The control and acquisition system is connected to the laser scanning device, receives the laser signal fed back by the laser scanning device, and generates a three-dimensional model according to the laser signal; when there are wear defects on the three-dimensional model, the control and acquisition system also measures the size of the wear defects on the three-dimensional model through a measurement module.

9. A method for measuring the inner surface wear of the bell mouth of a control rod drive mechanism thermal sleeve, characterized in that: The control rod drive mechanism thermowell bell mouth inner surface wear measurement system according to any one of claims 1 to 8 is adopted, and the control rod drive mechanism thermowell bell mouth inner surface wear measurement method comprises the following steps: S1. Pushing a multi-degree-of-freedom mechanical device equipped with a laser scanning device into the top cover of a nuclear reactor pressure vessel; S2, controlling the multi-degree-of-freedom mechanical device to rotate until the laser scanning device is sent to the position directly below the bell mouth of the thermowell of the control rod driving mechanism on the top cover, and the axis of the laser scanning device is coincident or approximately coincident with the axis of the bell mouth of the thermowell; S3, performing laser scanning on the inner surface of the bell mouth of the thermal sleeve by the laser scanning device, and sending the acquired laser signal to the control and acquisition system; S4. The control and acquisition system generates a three-dimensional model of the inner surface of the bell mouth of the thermal sleeve according to the received laser signal; when there is a wear defect on the three-dimensional model, the measurement module measures the size of the wear defect on the three-dimensional model.

10. The method for measuring the inner surface wear of the bell mouth of the control rod drive mechanism thermal sleeve according to claim 9, characterized in that: In step S2, the relative position relationship between the axis of the laser scanning device and the axis of the bell mouth of the thermal sleeve is obtained by real-time shooting of the centering camera unit of the laser scanning device; Step S2 also includes: lifting the laser scanning device by a third mechanical arm of the multi-degree-of-freedom mechanical device until the bell mouth of the thermal sleeve is within the effective working range of the laser scanning device.

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