Reactor pressure shell automatic adjustment grinding device and method

Abstract

The present invention belongs to the field of nuclear power plant reactor maintenance, and specifically relates to an automatic adjustment grinding device and method for a reactor pressure shell, the grinding device includes a bearing plate, a guide plate, a bolt, a support rod, a handle, a positioning nut, a grinding blank, a spherical bearing, a guide sleeve, a spring and a nut, and the grinding device is a central symmetrical structure. The grinding device is mostly connected in the form of welding, and small parts are mostly wrapped inside the device, and the outside is reliably sealed. The design reduces the risk of foreign matter falling, improves work efficiency, shortens working time, reduces the radiation dose of personnel, improves grinding quality, technically reduces the possibility of scrapping the pressure shell due to uneven grinding, improves the availability of equipment, and lays a good foundation for such work in future overhauls.

Description

Technical Field

[0001] The invention belongs to the field of nuclear power plant reactor maintenance, and in particular relates to an automatic adjustment grinding device and method for a reactor pressure shell. Background Art

[0002] As an important part of the reactor core, the control rod drive mechanism is mainly used to move the control rod up and down and fix it at the top, bottom or middle position. The position information of the control rod can be determined by the position indicator. By inserting or withdrawing the control rod from the core using the control rod drive mechanism, power startup, power control and shutdown can be achieved. There are 103 sets of control rod drive mechanisms in the upper assembly. The pressure shell is a flanged sleeve made of stainless steel, which is used to place the inner and outer parts of the control rod drive mechanism to ensure that the control rod drive mechanism works under the parameters of the first circuit. The lower flange of the pressure shell is connected to the control rod drive mechanism pipe on the reactor top cover; the upper part forms a closed pressure shell through the end plug. The sealing of the end plug is achieved by a sealing gasket. As the sealing pressure boundary of the first circuit, it needs to bear the operating pressure of 15.7MPa and the water pressure test pressure of 24.5MPa, which is a key seal.

[0003] When sealing the position indicator, according to the procedure requirements: wipe the sealing surface of the pressure shell with white cotton cloth dipped in alcohol; use a strong light to visually inspect the sealing surface of the pressure shell and the position indicator. There must be no indentation, protrusion, metal nodule, graphite gasket residue and other damage; the scratch on the sealing surface is not allowed to exceed 0.1mm. If it exceeds 0.1mm, it will be handled according to a separate plan. If defects are found on the non-sealing surface, use assorted files and sandpaper to handle it.

[0004] During the cold shutdown and maintenance of the unit, the inner wall seal of the pressure shell was scratched when the position indicator was removed from the pressure shell due to human operation, dimensional processing defects of the equipment itself, and environmental influences. When the position indicator was installed to the pressure shell, it could not be installed to the designed position and could not meet the installation requirements. After measurement and comparison, the sealing position of the pressure shell needs to be rationally ground. In the existing technical procedures, only local and simple processing is performed on the defects of the sealing surface of the pressure shell, and the full circumferential processing cannot meet the technical requirements. In addition, the existing processing technology is greatly limited by the manual level, which can easily cause the equipment defects to expand, which is time-consuming, labor-intensive, and labor-intensive.

[0005] Therefore, it is necessary to invent an automatic adjustment grinding device for the reactor pressure vessel which is easy to operate and automatically aligns to solve the above technical problems. Summary of the invention

[0006] The purpose of the present invention is to provide an automatic adjustment grinding device and method for a reactor pressure shell with defective sealing surfaces, which can process the sealing surface and is adjustable, improve work efficiency, reduce manpower input, and reduce radiation dose, while solving the technical problems of unstable centering and grinding force in the prior art.

[0007] The technical solution of the present invention is:

[0008] The invention discloses an automatic adjustment grinding device for a reactor pressure shell. The device is symmetrically arranged with the center of a bearing plate as the central axis, and comprises a bearing plate, a guide piece, a bolt, a support rod, a handle, a positioning nut, a grinding blank, a joint bearing, a guide sleeve, a spring and a nut. The fixing bolt and the grinding blank are fixedly connected by a nut. One end of the joint bearing is connected to the grinding blank, and the other end is connected to the guide piece. The guide sleeve passes through the bearing plate, and the protruding edge of the guide piece is embedded in the through groove of the guide sleeve. The bearing plate is connected to the support rod, and two joint bearings are connected by a spring. The support rod is connected to the handle.

[0009] The bearing plate is connected to the support rod by welding, and the support rod is connected to the handle by welding.

[0010] The guide sleeve and the bearing plate are fastened together by means of a positioning nut.

[0011] The extended ends on both sides of the guide sleeve are connected with two positioning nuts.

[0012] The guide sleeve is cylindrical, has threads on the outside and symmetrical through grooves on both ends.

[0013] The inner hole of the guide piece is a threaded hole.

[0014] The outer diameter of the ground blank is consistent with the inner diameter of the ground pressure-resistant shell.

[0015] The joint bearing head is ball-connected.

[0016] The spring is a compression spring.

[0017] The method for automatically adjusting the grinding of a reactor pressure shell specifically comprises using bolts to compress two grinding blanks to a size smaller than the inner diameter of the pressure shell, pasting grinding media on the arc surface of the grinding blanks, installing the grinding device on the defective pressure shell, and performing the grinding work clockwise or counterclockwise.

[0018] The present invention has the following beneficial effects:

[0019] (1) The design of the present invention reduces manpower input, and only two people are required to handle such defects, thereby improving work efficiency;

[0020] (2) The design of the grinding device provided by the present invention is mostly connected in the form of welding, and small parts are mostly wrapped inside the device, with a reliable seal on the outside, which reduces the risk of foreign matter falling from the design. Due to the uneven skills of operators, excessive grinding or grinding that does not meet the requirements may occur, resulting in the scrapping of the equipment. The design of the device solves the problem of unstable force, reduces human errors, improves work efficiency, shortens working hours, and reduces the radiation dose to personnel.

[0021] (3) The present invention reduces the number of workers, improves the efficiency of sealing surface grinding, shortens working hours, and reduces the radiation dose;

[0022] (4) The device of the present invention has a self-adaptive adjustment function, uniform circumferential grinding, improved grinding quality, technically reduced the possibility of pressure hull scrapping due to uneven grinding, and improved equipment availability;

[0023] (5) The device of the present invention is easy to operate and can be automatically centered. It technically solves the problems of centering and unstable grinding force, reduces the possibility of being unable to complete the work due to the limitation of the operator's operating level, and lays a good foundation for such work in future overhauls. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a front view of an automatic adjustment grinding device for a reactor pressure vessel provided by the present invention;

[0025] Figure 2 It is a side view of an automatic adjustment grinding device for a reactor pressure vessel provided by the present invention;

[0026] Figure 3 This is an AA cross-sectional view of an automatic adjustment grinding device for a reactor pressure vessel provided by the present invention;

[0027] Figure 4 This is a cross-sectional view BB of an automatic adjustment grinding device for a reactor pressure vessel provided by the present invention;

[0028] Among them: 1-carrying plate, 2-guide plate, 3-bolt, 4-support rod, 5-handle, 6-positioning nut, 7-grinding blank, 8-spherical bearing, 9-guide sleeve, 10-spring, 11-nut DETAILED DESCRIPTION

[0029] The technology of the present invention is further described below:

[0030] like Figure 1 , 2As shown in Figures 3 and 4, an automatic adjustment grinding device for a reactor pressure shell provided by the present invention is symmetrically arranged with the center of the bearing plate 1 as the central axis, comprising a bearing plate 1, two guide plates 2, two bolts 3, two support rods 4, a handle 5, four positioning nuts 6, two grinding blanks 7, two spherical bearings 8, a guide sleeve 9, a spring 1 and two nuts 11. The bolt 3 is threadedly connected to the grinding blank 7, and the bolt 3 is tightened to prevent loosening by the nut 11. One end of the spherical bearing 8 is threadedly connected to the grinding blank 7, and the other end is threadedly connected to the guide plate 2. The protruding edge of the guide plate 2 is embedded in the through groove of the guide sleeve 9. The guide sleeve 9 passes through the bearing plate 1, and the guide sleeve 9 and the bearing plate 1 are tightened by the positioning nuts 6 at both ends. The outer end of the guide sleeve 9 is threadedly connected to the positioning nuts 6. The bearing plate 1 is connected to the support rod 4 by welding. The two spherical bearings 8 are connected by a spring 10, and the support rod 4 is connected to the handle 5 by welding.

[0031] The guide sleeve 9 is cylindrical, has threads on the outside, and has symmetrical through grooves at both ends.

[0032] The inner hole of the guide piece 2 is a threaded hole, which is threadedly connected to the spherical bearing 8 .

[0033] A limited gap is formed between the two positioning nuts 6 on the same side, and the protruding edge of the guide piece 2 is limited between the two positioning nuts 6 to play a limiting role.

[0034] The spring 10 is a compression spring, which provides radial force for the device.

[0035] The outer diameter of the grinding blank 7 is consistent with the inner diameter of the ground pressure-resistant shell, and the head of the spherical bearing 8 is a ball connection, which ensures the automatic fit of the grinding blank 7 and the pressure-resistant shell.

[0036] The bolt 3 is connected to the grinding blank 7 by a threaded connection, and the bolt 3 is tightened to prevent loosening by a nut 11. When the grinding device is installed, the bolt 3 serves as a handle to compress the two grinding blanks 7 to prevent longitudinal scratches on the pressure-resistant shell.

[0037] After the grinding device is debugged on the pressure-resistant shell simulation part, the threaded connections of the grinding device can be welded as needed to prevent loosening and achieve the purpose of preventing foreign matter.

[0038] The present invention also provides an automatic adjustment grinding method for a reactor pressure shell, which specifically includes compressing two grinding blanks 7 to a size smaller than the inner diameter of the pressure shell through bolts 3, pasting grinding media, including grinding sandpaper, etc., on the curved surface of the grinding blanks 7, installing the grinding device on the defective pressure shell, and performing grinding work clockwise or counterclockwise according to actual conditions until the inner diameter of the pressure shell meets the use requirements.

[0039] In the original working mode, only sandpaper or processing grinding blank 7 is used. The grinding blank 7 is of fixed size and slightly smaller than the inner diameter of the pressure shell. The defective pressure shell can only be partially over-grinded. Compared with the original design, the sealing effect is reduced to a certain extent. The pressure shell is a nuclear-grade equipment of the original factory, and its cost, inspection and transportation costs are relatively high. The use of this device solves the problems of grinding eccentricity and unstable force control from a technical point of view, greatly improves the grinding pass rate, and indirectly reduces the scrap rate of the pressure shell. In addition, the pressure shell seal is used as a primary circuit sealing boundary, and the defect is quickly and effectively handled to avoid delays in the main line of overhaul, with great potential economic benefits. The design of the grinding device is mostly connected in the form of welding, and small parts are mostly wrapped inside the device, and there is a reliable seal on the outside, which reduces the risk of foreign matter falling from the design. Due to the uneven skills of the operators, over-grinding or grinding that does not meet the requirements may occur, resulting in the scrapping of the equipment. The device solves the problem of unstable force from the design point of view, reduces human errors, improves work efficiency, shortens working hours, and reduces the radiation dose of personnel.

[0040] The present invention is described in detail above in conjunction with the embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present invention. The contents not described in detail in the present invention can adopt the existing technology.

Claims

1. A reactor pressure vessel automatic adjustment grinding device, characterized in that: The device is symmetrically arranged with the center of the bearing plate (1) as the central axis, and comprises a bearing plate (1), a guide plate (2), a bolt (3), a support rod (4), a handle (5), a positioning nut (6), a grinding blank (7), a joint bearing (8), a guide sleeve (9), a spring (10) and a nut (11). The bolt (3) and the grinding blank (7) are fixedly connected by the nut (11); one end of the joint bearing (8) is connected to the grinding blank (7) and the other end is connected to the guide plate (2); the guide sleeve (9) passes through the bearing plate (1); the protruding edge of the guide plate (2) is embedded in the through groove of the guide sleeve (9); the bearing plate (1) is connected to the support rod (4); the two joint bearings (8) are connected by the spring (10); and the support rod (4) is connected to the handle (5).

2. The automatic adjustment grinding device for a reactor pressure vessel according to claim 1, characterized in that: The bearing plate (1) and the support rod (4) are connected by welding, and the support rod (4) and the handle (5) are connected by welding.

3. The automatic adjustment grinding device for a reactor pressure vessel according to claim 2, characterized in that: The guide sleeve (9) and the bearing plate (1) are fastened together via a positioning nut (6).

4. The automatic adjustment grinding device for a reactor pressure vessel according to claim 3, characterized in that: The extended ends on both sides of the guide sleeve (9) are connected to two positioning nuts (6).

5. The automatic adjustment grinding device for a reactor pressure vessel according to claim 4, characterized in that: The guide sleeve (9) is cylindrical, has external threads, and has symmetrical through grooves at both ends.

6. The automatic adjustment grinding device for a reactor pressure vessel according to claim 5, characterized in that: The inner hole of the guide piece (2) is a threaded hole.

7. The automatic adjustment grinding device for a reactor pressure vessel according to claim 6, characterized in that: The outer diameter of the grinding blank (7) is consistent with the inner diameter of the ground pressure-resistant shell.

8. The automatic adjustment grinding device for a reactor pressure vessel according to claim 7, characterized in that: The head of the joint bearing (8) is ball-connected.

9. The reactor pressure vessel automatic adjustment grinding device according to claim 8, characterized in that: The spring (10) is a compression spring.

10. A grinding method for a reactor pressure vessel automatic adjustment grinding device according to any one of claims 1 to 9, characterized in that: The method specifically comprises using bolts (3) to compress two grinding blanks (7) to a size smaller than the inner diameter of a pressure-resistant shell, pasting grinding media on the arc surface of the grinding blanks (7), installing a grinding device on the defective pressure-resistant shell, and performing grinding in a clockwise or counterclockwise direction.

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