Flotation device for checking safety injection connecting pipe of reactor pressure vessel

Abstract

The invention provides a planktonic device for checking a safety injection connecting pipe of a reactor pressure vessel. The planktonic device is characterized in that a driving mechanism is mounted in a box body; the guide fixing module is mounted at the first end part of the box body; the propellers are respectively mounted on two sides, close to the first end part, of the box body and on the first end part and the second end part of the box body, and are used for pushing the floating device to float, sink, advance, retreat and steer; the plurality of scanners are mounted at the end part of the guiding and fixing module and are driven by the driving mechanism to scan the inner wall of the connecting pipe to be inspected; the buoyancy mechanisms are installed on the box body and used for providing buoyancy for the box body. And the counterweight unit is mounted at the second end part of the box body and is used for keeping the balance of the planktonic device. The propeller on the device is controlled through the controller, the device floats, sinks, advances, retreats and steers underwater, the scanners are installed, the scanners make constant-pressure contact with the inner wall of the connecting pipe, and therefore simultaneous scanning of the scanners is achieved.

Description

Technical Field

[0001] This invention relates to the field of nuclear energy equipment inspection, and in particular to a flotation device for inspecting the safety injection pipes of a reactor pressure vessel. Background Technology

[0002] In existing technologies, the reactor pressure vessel (RPV) of a nuclear power plant is a crucial component of the reactor coolant pressure boundary. The safety end of the reactor pressure vessel, specifically the connection between the inlet and the main piping, consists of two welds: one between the inlet and the safety end, and another between the safety end and the main piping. Located close to the active zone of the reactor core, the safety end must withstand alternating complex stresses and corrosion under high temperature, high pressure, and high radiation conditions during nuclear power plant operation.

[0003] In accordance with standards related to the construction, installation, and operation of nuclear power plants, including ASME specifications and RSE-M standards, the aforementioned welds require regular quality inspections. This is an important part of pre-service and in-service inspections of nuclear power plants. The quality of this work is crucial to ensuring the integrity of the primary loop system.

[0004] The current inspection method mainly involves ultrasonic testing of the inner wall. For example, inspection can be carried out using a robotic arm equipped with a scanner, or automatic scanning of the weld seams at the safety end cannot be performed due to interference from the spatial structure.

[0005] In view of this, the inventors of this application have designed a flotation device for inspecting the safety injection pipe of a reactor pressure vessel, in order to overcome the above-mentioned technical problems. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiency of the prior art in that there is no suitable inspection device for inspecting the inner wall of the safety injection pipe of the reactor pressure vessel, and to provide a float device for inspecting the safety injection pipe of the reactor pressure vessel.

[0007] The present invention solves the above-mentioned technical problems through the following technical solution:

[0008] A flotation device for inspecting safety injection lines in a reactor pressure vessel, characterized in that the flotation device comprises:

[0009] A housing and a drive mechanism, wherein the drive mechanism is installed inside the housing;

[0010] A guide fixing module is installed at the first end of the housing;

[0011] Multiple thrusters are respectively mounted on both sides of the housing near the first end, and on the first and second ends of the housing, for propelling the floating device to float, sink, move forward, move backward, and turn;

[0012] Multiple scanners are installed at the end of the guide fixing module and driven by the drive mechanism to scan the inner wall of the pipe to be inspected.

[0013] Multiple buoyancy mechanisms are mounted on the housing to provide buoyancy to the housing;

[0014] A counterweight unit is installed at the second end of the housing to maintain the balance of the floatation device.

[0015] According to one embodiment of the present invention, a bracket is installed on the first end of the housing, and the guide fixing module is fixed on the bracket.

[0016] According to one embodiment of the present invention, the floatation device further includes a fastening mechanism mounted on the bracket and located below the guide fixing module.

[0017] According to one embodiment of the present invention, the floating device further includes an underwater camera, which is mounted on the bracket and located below the guide and fixing module.

[0018] According to one embodiment of the present invention, the floating device includes four propellers, two of which are mounted on both sides of the first end, a third of which is mounted on the upper part of the first end, and a fourth of which is mounted on the upper part of the second end.

[0019] According to one embodiment of the present invention, the propeller is a propeller.

[0020] According to one embodiment of the present invention, the floatation device includes three buoyancy mechanisms, one of which is mounted on the upper part of the housing, near the first end;

[0021] The other two buoyancy mechanisms are respectively installed on both sides of the first end of the box.

[0022] According to one embodiment of the present invention, the buoyancy mechanism is a buoyancy water tank.

[0023] According to one embodiment of the present invention, the floatation device further includes a lifting cup, which is installed on the upper part of the housing and located at the center of gravity of the floatation device.

[0024] According to one embodiment of the present invention, the float device further includes a plurality of anti-fall rings and cables, the anti-fall rings being respectively disposed on the upper part of the housing, and the cables being installed at the second end of the housing.

[0025] The positive and progressive effects of this invention are as follows:

[0026] The float device of the present invention for inspecting safety injection lines of reactor pressure vessels has the following advantages:

[0027] 1. By controlling the four thrusters on the device via the controller, the device can achieve buoyancy, descent, forward movement, backward movement, and turning underwater;

[0028] 2. Install multiple sets of scanners, each scanner can be equipped with 2 ultrasonic probes. The cylinder drives the connecting rod assembly to achieve constant pressure contact between the scanner and the inner wall of the pipe, and multiple sets of scanners can also be used for simultaneous scanning. Attached Figure Description

[0029] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features, wherein:

[0030] Figure 1 This is a schematic diagram of the flotation device for inspecting the safety injection pipe of a reactor pressure vessel according to the present invention.

[0031] Figure 2 This is a diagram showing the operational status of the float device used for inspecting the safety injection nozzles of a reactor pressure vessel according to the present invention. Detailed Implementation

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] Embodiments of the invention will now be described in detail with reference to the accompanying drawings. Preferred embodiments of the invention will now be described in detail, examples of which are shown in the drawings. Wherever possible, the same reference numerals will be used in all the drawings to denote the same or similar parts.

[0034] Furthermore, although the terminology used in this invention is selected from commonly known and used terms, some terms mentioned in this specification may have been selected by the applicant in his or her judgment, and their detailed meanings are explained in the relevant sections of the description herein.

[0035] Furthermore, the invention should be understood not only through the actual terminology used, but also through the meaning implied by each term.

[0036] Figure 1 This is a schematic diagram of the flotation device for inspecting the safety injection pipe of a reactor pressure vessel according to the present invention. Figure 2 This is a diagram showing the operational status of the float device used for inspecting the safety injection nozzles of a reactor pressure vessel according to the present invention.

[0037] like Figure 1 and Figure 2 As shown, this invention discloses a flotation device for inspecting the injection pipes of a reactor pressure vessel, comprising: a housing 10, a drive mechanism (not shown), a guide and fixing module 20, multiple thrusters 30, multiple scanners 40, multiple buoyancy mechanisms 50, and a counterweight unit 60. The drive mechanism is installed inside the housing 10.

[0038] The guide fixing module 20 is installed at the first end 11 of the housing 10. Preferably, a bracket 13 is installed on the first end 11 of the housing 10, and the guide fixing module 20 is fixed on the bracket 13.

[0039] Additionally, the floatation device includes a fastening mechanism 70, which is mounted on the bracket 13 and located below the guide fixing module 20. Axial positioning of the floatation device is crucial to ensure that the scanner 40 on the floatation device can be aligned with the safety end weld inside the connector and to accurately locate detected defects. The floatation device is fitted to the inner surface of the connector via the guide fixing module 20, and then expanded to fit against the inner wall of the connector protrusion via the fastening mechanism 70 at the front connector opening. The internal level and vertical alignment of the floatation device is observed to ensure that the floatation device is horizontally and vertically aligned with the connector.

[0040] The thrusters 30 are respectively installed on both sides of the housing 10 near the first end 11, and on the first end and the second end 12 of the housing 10, for propelling the floating device to float, sink, move forward, move backward and turn.

[0041] Preferably, the floating device includes four propellers 30, two of which are installed on both sides of the first end 11, the third propeller 30 is installed on the upper part of the first end 11, and the fourth propeller 30 is installed on the upper part of the second end 12. Here, all propellers 30 can preferably be propellers.

[0042] For example, the floating device is equipped with four propellers. Two are installed at the top of the device, one at the front and one at the back. Two are installed on both sides of the device. By controlling the rotational speed and direction of the two horizontal propellers and the two vertical propellers, the floating device can achieve four degrees of freedom of movement.

[0043] The scanner 40 is installed at the end of the guide fixing module 20 and is driven by the drive mechanism to scan the inner wall of the pipe to be inspected. The scanner 40 moves axially through the extension and retraction of the lead screw inside the float device, and then the internal cylinder opens the fastening mechanism 70 to fit against the inner wall of the pipe. The cylinder can be equivalent to a spring, providing flexible control.

[0044] The scanner 40 is driven by a motor to drive a lead screw, which enables the scanner to feed axially and rotate circumferentially. The force of the cylinder is applied to the scanner 40 to make the scanner 40 fit against the weld area to be inspected. Ultrasonic detection is achieved by installing a probe on the scanner 40.

[0045] A buoyancy mechanism 50 is mounted on the housing 10 to provide buoyancy to the housing 10. In this embodiment, the floatation device includes three buoyancy mechanisms 50, one of which is mounted on the upper part of the housing 10, near the first end 11. The other two buoyancy mechanisms 50 are respectively mounted on both sides of the first end 11 of the housing 10.

[0046] The buoyancy mechanism 50 here can preferably be a buoyancy tank. For example, the floatation device can be configured with three buoyancy tanks, with two buoyancy tanks at the front of the tank body 10 and one buoyancy tank at the top.

[0047] In this embodiment, the purpose of adding a buoyancy tank is to ensure that the floatation device is essentially suspended in water, requiring only a small force to drive the propeller (i.e., the thruster 30) to move the floatation device up and down. Furthermore, the buoyancy tank is adjustable and can be filled with water. When it is necessary to adjust the balance of the floatation device in the water, simply add or remove water.

[0048] A counterweight unit 60 is installed at the second end 12 of the housing 10 to maintain the balance of the floatation device. Since the front end (i.e., the first end 11) of the floatation device is relatively heavier than the rear end (i.e., the second end 12), a counterweight is added at the rear end to ensure balance during hoisting. The counterweight unit 60 can be composed of multiple counterweight blocks stacked sequentially.

[0049] Furthermore, the floating device also includes an underwater camera 80, which is mounted on the bracket 13 below the guide and fixing module 20. The underwater illuminated camera can be used to locate the manhole cover.

[0050] The floatation device also includes a positioning sensor 90, which is mounted on the bracket 13 and located on the side of the guide and fixing module 20. The positioning sensor 90 is used to detect whether the floatation device has reached the installation position. After the floatation device enters the connecting pipe, when the positioning sensor is in contact with the inner wall of the container, the sensor sends a feedback command indicating that the floatation device has reached the installation position.

[0051] The floatation device also includes a lifting cup 100, which is installed on the upper part of the housing 10, located at the center of gravity of the floatation device. The floatation device has a lifting cup holder (such as...) on top. Figure 1As shown, the floating device is placed into the pressure vessel using a lifting device, and then manually inserted into the pipe using a long-handled tool.

[0052] The floatation device also includes multiple anti-fall rings 110, which are respectively installed on the upper part of the housing 10. Steel wires are attached to the anti-fall rings 110, which serve both to prevent the floatation device from falling and to provide traction.

[0053] In addition, the floating device is also equipped with a cable 120, which is installed at the second end 12 of the housing 10.

[0054] Based on the above structural description, the key feature of the float device for inspecting the safety injection nozzle of a reactor pressure vessel according to the present invention is that the structure of the detection device should ensure correct installation, reliable positioning, and complete scanning, ensuring the correct position of the device to be inspected 200 in the nozzle and the correct position of the probe relative to the weld to be inspected. The probe is in constant contact with the area to be inspected. The float device is installed with a buoyancy tank and a counterweight unit, and the buoyancy adjustment is convenient.

[0055] The following section will focus on the structural composition of the detection device, specifically the functions of each part from five aspects: positioning mechanism, scanner transmission mechanism, gearbox transmission mechanism, scanner clamping mechanism, and auxiliary mechanism.

[0056] I. Positioning Mechanism

[0057] The floatation device is secured in the tube by the front guide and fixing module 20 and the front lower tube port clamping device (i.e., fastening mechanism 70). The tube port clamping device is equipped with nylon gaskets to prevent damage to the internal surface of the tube during clamping. The buoyancy generated by the front, rear, and head buoyancy mechanisms 50 is slightly greater than the weight of the floatation device. Since the driving force generated by the propeller is limited, a counterweight unit 60 is required to cooperate with the propeller to achieve buoyancy and sinking of the floatation device.

[0058] The entire frame of the aforementioned floating device consists of a housing 10 and a front-end guiding assembly (i.e., a guiding and fixing module 20). A lifting cup 100 is located on the upper middle surface for hoisting it into the pressure vessel. Vertical propellers (i.e., thrusters 30) are located at the front and rear ends of the upper surface of the housing 10 for the floating device's ascent and descent. Horizontal propellers (i.e., thrusters 30) are located on both sides of the housing 10 for the floating device's forward and backward movement.

[0059] II. Transmission Mechanism of the Scanner

[0060] The transmission mechanism of the scanner 40 is installed inside the housing. The circumferential movement of the scanner 40 is achieved by directly driving the scanner assembly to rotate via a motor with a reducer. The circumferential rotary motor and the reducer are installed inside the circumferential rotary motor compartment.

[0061] For example, a planetary gear reducer is used to increase the reduction ratio, reduce the scanning speed of the scanner 40, and increase the output torque. The reducer is connected to the motor compartment end cover via a transition flange; the motor compartment end cover is designed primarily for ease of installation.

[0062] III. Gearbox Transmission Mechanism

[0063] The gearbox is installed inside the floating device. To achieve the axial feed of the scanner 40, a drive method is adopted in which the lead screw is stationary and the nut rotates. The entire scanner assembly and its transmission mechanism are installed at one end of the drive lead screw, which drives its back-and-forth movement.

[0064] IV. Fastening mechanism of the scanner

[0065] The scanner needs to perform two actions: circumferential rotation and axial feed. These are achieved through the scanner's transmission mechanism and gearbox transmission mechanism, respectively.

[0066] The scanner 40 is mounted on the guide rod cylinder, and the probe is mounted on the scanner. Since the probe needs to remain in contact with the weld area to be inspected during the inspection process, a certain force needs to be applied to the scanner. This paper uses the clamping force of the cylinder to achieve this, ensuring that this force is constant.

[0067] V. Auxiliary Facilities

[0068] Buoyancy tank device: Preferably, the floatation device includes three buoyancy tanks: one on each side and one at the top. The purpose of these tanks is to ensure the detection device remains essentially suspended in water, requiring only a small force to move the propeller up and down. The tanks are adjustable and filled with water. Adjusting the floatation device's balance in the water is achieved simply by adding more water to the tanks.

[0069] Propeller drive mechanism: composed of Figure 1 As shown, the floating device can preferably be equipped with four propellers. Two vertical propellers are installed on the upper part of the floating device, and the other two horizontal propellers are installed on both sides of the floating device. By controlling the rotational speed and direction of the two horizontal propellers and the two vertical propellers, the detection device can achieve four degrees of freedom of movement.

[0070] Scanner Mechanism: The float device is preferably equipped with a scanner. Since three sets of ultrasonic probes (two in each set) are installed on the scanner and enter the inside of the nozzle, all the work of weld defect detection can be completed in one go. This can effectively avoid the problem of repeated positioning error when a single scanner enters the nozzle twice.

[0071] Manual feeding mechanism: such as Figure 1 As shown, a quick-connect coupling is installed on the upper part of the floating device. When the propeller malfunctions and the floating device cannot automatically enter the connecting pipe, a long-handled tool can be connected to the quick-connect coupling, and the operator can stand on a mobile platform and send the detection device into the connecting pipe through underwater television monitoring.

[0072] The flotation device of the present invention for inspecting the safety injection nozzles of reactor pressure vessels has the following features:

[0073] I. An underwater floating mechanism was designed, with buoyancy boxes installed at the top and bottom of the front of the device, so that the buoyancy is slightly greater than the weight of the device.

[0074] II. Floating control of the device: By controlling multiple thrusters (e.g., 4) on the device through the controller, the device can be made to float, sink, move forward, move backward, and turn underwater.

[0075] 3. Connector support mechanism: A support cylinder is installed at the front end of the device. After the device enters the inside of the connector, the two cylinders extend and contact the inner wall of the saddle-shaped protrusion of the connector to complete the device support.

[0076] IV. Ultrasonic two-dimensional scanning structure, which consists of two motors to complete circumferential and axial scanning, enabling a one-time scanning operation.

[0077] V. Scanners and their fastening mechanism. The device can be equipped with three sets of scanners, each scanner can be equipped with two ultrasonic probes. A cylinder drives the connecting rod assembly to achieve constant pressure contact between the scanner and the inner wall of the pipe. At the same time, all three sets of scanners can be used for scanning simultaneously.

[0078] VI. The device is equipped with a positioning sensor, which is used to measure the tilt angle of the floating device after the internal support of the nozzle is positioned, for the precise location of defects.

[0079] 7. Pneumatic control completes the support and positioning of the device, the sticking and retraction of the scanner, and the pressure maintenance of the motor compartment.

[0080] This invention relates to a flotation device for inspecting safety injection lines in reactor pressure vessels. The device's structure should ensure correct installation, reliable positioning, and complete scanning. Based on domestic and international research, a key feature of the mechanical design of this inspection device is automatic axial positioning, ensuring the correct position of the device under inspection within the line and the correct position of the probe relative to the weld to be inspected.

[0081] First, the installation of the float device includes: the lifting plug of the detection device is used to lift it into the pressure vessel, and the detection device is fixed to the inlet by a positioning and clamping cylinder.

[0082] Next, the scanner moves: the scanner design needs to achieve two actions: circumferential rotation and axial feed. This is achieved through the scanner's transmission mechanism. The scanner is mounted on a double-guide-rod cylinder, and the probe is mounted on the scanner. Since the probe needs to remain in contact with the weld area to be inspected during the inspection process, a certain force needs to be applied to the scanner. In this embodiment, the clamping force of the cylinder is used to achieve this, and this force is ensured to be constant.

[0083] In addition, the selection of functional components includes: selecting a suitable motor based on the load torque, a camera based on the structural space, and a suitable sensor for the usage environment.

[0084] The design of this floating device meets the operational requirements of a nuclear power company for the safety injection connection inspection of the reactor pressure vessel. During the research and design process, continuous learning and research were conducted on the floating device control system, especially for applications in the special environment of nuclear power plants, which improved the stability of the control system and provides guidance for the control systems of other special robots.

[0085] Furthermore, the aforementioned floating device can align with the development direction of nuclear power robot technology, enhance the design level of nuclear power robots, and further promote the localization of nuclear power robots. It can also enrich the application functions of domestically produced automated nuclear power plant inspection and maintenance equipment, thereby improving automated inspection and maintenance capabilities.

[0086] For those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0087] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0088] Similarly, it should be noted that, in order to simplify the description of the embodiments disclosed in this application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of this application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of this application requires more features than those mentioned in the claims. In fact, the embodiments have fewer features than all the features of the single embodiments disclosed above.

[0089] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A float device for reactor pressure vessel nozzle inspection, characterized by, The floating device comprises: a box body and a driving mechanism installed in the box body; a guide fixed module installed at a first end of the box body; a plurality of propellers installed on both sides of the box body near the first end, and on the first end and a second end of the box body, for pushing the floating device to float, sink, move forward, move backward and turn; a plurality of scanners installed at the end of the guide fixed module, driven by the driving mechanism to scan the inner wall of the pipe under inspection; a plurality of buoyancy mechanisms installed on the box body to provide buoyancy for the box body; a counterweight unit installed at the second end of the box body to keep the balance of the floating device.

2. The float device for inspection of a reactor pressure vessel injection nozzle of claim 1, wherein, A support is installed on the first end of the box body, and the guide fixed module is fixed on the support.

3. The float device for inspection of a reactor pressure vessel injection nozzle of claim 2, wherein, The floating device further comprises a fastening mechanism installed on the support below the guide fixed module.

4. The float device for inspection of reactor pressure vessel injection nozzle connections of claim 2, wherein, The floating device further comprises an underwater camera installed on the support below the guide fixed module.

5. The floater apparatus for inspection of reactor pressure vessel injection nozzle of claim 1, wherein, The floating device comprises four propellers, two of which are installed on both sides of the first end, the third is installed on the upper part of the first end, and the fourth is installed on the upper part of the second end.

6. The float device for inspection of a reactor pressure vessel injection nozzle of claim 5, wherein, The propeller is a propeller.

7. The float device for inspection of reactor pressure vessel injection nozzle of claim 1, wherein, The floating device comprises three buoyancy mechanisms, one of which is installed on the upper part of the box body near the first end. The other two buoyancy mechanisms are respectively installed on both sides of the first end of the box body.

8. The float device for inspection of a reactor pressure vessel injection nozzle of claim 7, wherein, The buoyancy mechanism is a buoyancy tank.

9. The float device for inspection of a reactor pressure vessel injection nozzle of claim 1, wherein, The floating device further comprises a lifting cup mouth installed on the upper part of the box body at the center of gravity of the floating device.

10. The floater apparatus for inspection of reactor pressure vessel nozzles of claim 1, wherein, The floating device further comprises a plurality of anti-falling lifting rings and cables, the anti-falling lifting rings are respectively arranged on the upper part of the box body, and the cables are installed on the second end of the box body.

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