A reactor pressure vessel main bolt thread loosening agent spraying device

Abstract

The present invention belongs to the technical field of nuclear power plant reactor maintenance, and specifically relates to a thread loosening agent spraying device for the main bolts of the reactor pressure vessel. The present invention includes three parts: an upper clamping assembly, a middle support assembly, and a lower adjustment assembly. The middle support assembly is the main structure of the entire spraying device, which is used to accommodate the thread loosening agent and limit its radial displacement, and at the same time serves as a gripping part when the staff holds the spraying device; the lower adjustment assembly is located at the lower end of the middle support assembly, and plays the role of supporting the bottom of the thread loosening agent tank and adjusting the thread loosening agent spraying flow; the upper clamping assembly is located at the upper end of the middle support assembly, and plays the role of clamping the top nozzle of the thread loosening agent and adjusting the direction of the thread loosening agent nozzle. The present invention improves the thread loosening agent spraying efficiency, avoids the occurrence of abnormal events that make it difficult to remove the main bolts, and at the same time reduces the total collective dosage value of the main bolt thread loosening agent spraying work.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear power plant reactor maintenance, and in particular relates to a thread loosening agent spraying device for main bolts of a reactor pressure vessel. Background Art

[0002] The first phase of a nuclear power plant project consists of two VVER-1000 units, and the reactor is a B-428 reactor. Each unit has 54 main bolts, which work together with the main bolt holes, main nuts and gaskets of the reactor pressure vessel to provide pre-tightening force for the seal between the reactor pressure vessel and the upper reactor assembly. The pre-tightening force acts on the main sealing ring through mechanical transmission, thereby realizing the sealing function of the reactor main sealing surface. The main bolt is a tensile bolt, which consists of a main bolt barrel, an upper thread plug and its gasket, a sleeve, a central measuring rod, a lower thread plug and its gasket. The total length of the bolt is 1950mm, and the weight of the single bolt is 306kg. The main bolt barrel has three main thread sections: the first thread section is S45°M160×6, which is used to connect the main bolt and the reaction nut of the bolt tensioning machine, and plays a connecting role in the tensioning process; the second thread section is M170×6-240, which is used to connect the main bolt and the main nut, and plays a role in fixing the top of the main bolt; the third thread section is M170×6-6e-230, which is used to connect the main bolt and the reactor pressure vessel, and plays a role in fixing the root of the main bolt.

[0003] During the overhaul of the unit, when the pressure vessel is covered and sealed, the main bolts are first screwed into the main bolt holes of the pressure vessel using a bolt tensioner. Then, the 54 main bolts are stretched at one time within the elastic deformation range of the main bolts using a bolt tensioner. The main nuts are tightened during the stretching process. After the nuts are tightened, the tensile force of the bolt tensioner is unloaded. At this time, the bottom of the main bolt is fixed, and the top is fixed by the main nut after being stretched. Under the joint action of the main nut and the reactor pressure vessel, the main bolt always maintains an elastic deformation state, thereby providing the necessary pre-tightening force for the sealing surface of the reactor pressure vessel. In the two processes of screwing the main bolt into the main bolt hole of the pressure vessel and tightening the main nut, in order to prevent the threads from biting, a thin layer of grease will be applied in advance to the threads of the main bolt hole of the pressure vessel, the main bolt threads, and the main nut threads. The main bolt grease is a mixture of 40% дми-7 molybdenum disulfide powder and 60% пэс molybdenum disulfide oil. During the next fuel cycle of the unit, the temperature of the main bolt working position is high, the molybdenum disulfide oil will automatically evaporate, and the molybdenum disulfide powder will automatically dry and harden and adhere to the threads of the main bolt hole, main bolt and main nut. The dried and hardened molybdenum disulfide grease increases the friction between the threads, which makes it extremely difficult to remove the main nut and main bolt in the next overhaul. According to maintenance experience, the hardened molybdenum disulfide grease will automatically soften after being soaked in the thread loosening agent WD-40 for a sufficient time. After softening, the main bolt and main nut can be removed smoothly. In order to achieve a better softening effect and prevent the difficulty in removing the main bolt, each overhaul needs to be sprayed three times to add thread loosening agent to the matching parts of the main bolt, main nut and main bolt hole, so that the loosening agent can slowly moisten and soften the dried molybdenum disulfide grease, and the pouring method cannot be used. On average, about 100 cans of thread loosening agent are required for each overhaul.

[0004] According to statistics, every overhaul will cause abnormal events in which multiple main bolts cannot be removed smoothly due to poor spraying effect of thread loosening agent. From the aspects of working environment, working methods and personnel behavior, the reasons for the poor spraying effect of thread loosening agent on some main bolts are found. The spraying of thread loosening agent on main bolts is carried out in the reactor shaft, where the ambient temperature is high and the ambient dose rate is large. In addition, the main bolts and the main bolt holes of the pressure vessel are close to the ground, and the workers need to squat or even lie on the ground to work. WD-40 thread loosening agent is a canned pressurized liquid, which is sprayed from the nozzle by continuously pressing the nozzle on the head of the tank. During on-site operations, the workers' hands are sore after pressing the nozzle for a long time, and they need to stop working to relax their hands. In this way, on the one hand, the working time is extended, and the effective softening time of thread loosening agent on molybdenum disulfide grease is correspondingly shortened; on the other hand, the workers' physical strength is further lost in the high temperature environment, and the collective absorbed dose of the workers is increased in the high radiation dose rate environment. Therefore, in the unfavorable working environment of high temperature and high radiation dose rate, the workers were affected by the poor working position, physical and energy limitations, and inherent human inertia, and the loosening agent was not sprayed sufficiently on the threads of some main bolts. The hardened molybdenum disulfide grease on the threads did not soften well, resulting in some main bolts being unable to be removed smoothly.

[0005] Regarding the main bolt thread loosening agent spraying work, in order to free the workers' hands, reduce the workers' burden, improve the thread loosening agent spraying efficiency, fully soften the hardened molybdenum disulfide grease on the threads, avoid the abnormal incident of difficulty in removing the main bolts, and at the same time reduce the total collective dose value of this work, it is urgently necessary to provide a reactor pressure vessel main bolt thread loosening agent spraying device. Summary of the invention

[0006] The objects of the present invention are:

[0007] According to the structural characteristics of the main bolt thread loosening agent and on-site use requirements, the present invention provides a reactor pressure vessel main bolt thread loosening agent spraying device, which frees the workers' hands, reduces the workers' burden, improves the thread loosening agent spraying efficiency, and fully softens the hardened molybdenum disulfide grease on the threads, avoiding the occurrence of abnormal events that make it difficult to remove the main bolts, while reducing the total collective dosage value of the main bolt thread loosening agent spraying work.

[0008] The technical solution adopted by the present invention is:

[0009] A reactor pressure vessel main bolt thread loosening agent spraying device comprises three parts: an upper clamping assembly, a middle support assembly and a lower adjustment assembly. The middle support assembly is the main structure of the entire spraying device, used to contain the thread loosening agent and limit its radial displacement, and at the same time serves as a gripping part when the staff holds the spraying device; the lower adjustment assembly is located at the lower end of the middle support assembly, and plays the role of supporting the bottom of the thread loosening agent tank and adjusting the thread loosening agent spraying flow; the upper clamping assembly is located at the upper end of the middle support assembly, and plays the role of clamping the top nozzle of the thread loosening agent and adjusting the direction of the thread loosening agent nozzle.

[0010] The middle support assembly includes an upper support plate, support columns, and a lower support plate. The upper support plate and the lower support plate are both circular ring structures, and circular through holes are evenly distributed on the circumference near the outer edge. The upper and lower ends of a plurality of support columns are respectively inserted into the circular through holes evenly distributed on the upper support plate and the lower support plate, and are welded and fixed.

[0011] A loading and unloading hole is opened in the middle of the upper support plate, and its diameter is slightly larger than the diameter of the thread loosening agent tank body, which serves as a channel for loading and discharging the thread loosening agent tank body into and out of the device; an internal thread through hole with internal threads is processed in the middle of the lower support plate.

[0012] The lower adjustment component includes a support adjustment piece and a handle. The lower part of the support adjustment plate is in the shape of a circular plate, and the upper part is a boss. The upper end face of the boss is designed to be a spherical surface, which perfectly fits the concave surface at the bottom of the thread loosening agent tank. The outer surface of the circular plate of the support adjustment plate is processed with an external thread, which cooperates with the internal thread of the inner circle of the lower support plate, so that the support adjustment piece can move up and down relative to the middle support assembly through the rotation of the thread, thereby realizing the opening and closing and flow adjustment of the thread loosening agent spraying; the handle is welded to the bottom surface of the support adjustment piece and serves as a knob for rotating the support adjustment piece.

[0013] The upper clamping assembly includes a support sleeve, a top load-bearing beam, and an adjustable pressure block. The support sleeve is welded to the upper surface of the upper support plate and is a circular tube structure with unclosed ends for accommodating and supporting the top load-bearing beam. The top load-bearing beam is installed on the support sleeve, and the adjustable pressure block is installed in the groove inside the top load-bearing beam and can rotate freely around the vertical axis.

[0014] An L-shaped keyway is processed in the upper middle part of the support sleeve; the top load-bearing beam is used to withstand the reaction force when squeezing the thread loosening agent nozzle, and its lower pin shaft is installed inside the support sleeve and rotates around the axis of the support sleeve. A cylindrical key is processed on the outer surface of the pin shaft, which cooperates with the L-shaped keyway and moves freely in the keyway.

[0015] When the key moves in the horizontal section of the L-shaped keyway, the top load-bearing beam rotates with a maximum rotation angle of 100°; when the key is in the vertical section of the L-shaped keyway, the top load-bearing beam is located just above the center of the loading and unloading hole and is restricted from rotating, and the spraying device is in working condition.

[0016] The lower end surface of the adjustable pressing block is an arc surface, which matches the pressing surface of the thread loosening agent nozzle.

[0017] The adjustable pressing block is connected to the top load-bearing beam via a connecting shaft in the middle and a positioning plate at the upper end.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The present invention provides a reactor pressure vessel main bolt thread loosening agent spraying device,

[0020] The introduction of semi-automatic thread loosening agent spraying device reduces the burden on staff, improves the efficiency of thread loosening agent spraying, avoids abnormal events such as difficulty in removing main bolts, and reduces the total collective dose value of main bolt thread loosening agent spraying work;

[0021] (2) The present invention provides a reactor pressure vessel main bolt thread loosening agent spraying device. Considering the lightness and flexibility of the device, the main structure adopts a cage structure, which can reduce the weight of the whole device to the maximum extent on the basis of meeting the overall structural strength, and at the same time facilitate the operator to observe and rotate and adjust the direction of the thread loosening agent tank;

[0022] (3) The present invention provides a reactor pressure vessel main bolt thread loosening agent spraying device, which uses a thread matching method to provide extrusion force to achieve continuous spraying of the thread loosening agent, and can flexibly adjust the spraying flow rate according to on-site needs;

[0023] (4) The present invention provides a reactor pressure vessel main bolt thread loosening agent spraying device, the contact surface between the device and the concave surface at the bottom of the thread loosening agent tank is designed to be a spherical surface, which increases the force-bearing area and prevents the device from squeezing the thread loosening agent tank too much and causing the tank to rupture;

[0024] (5) The present invention provides a reactor pressure vessel main bolt thread loosening agent spraying device. The L-shaped keyway and the key cooperate to form a loading and unloading channel quickly, making the thread loosening agent replacement simple and fast; on the other hand, the adjustable pressure block can be quickly positioned so that it is just above the thread loosening agent spray head, while ensuring that the top bearing beam does not rotate during the spraying process;

[0025] (6) The present invention provides a reactor pressure vessel main bolt thread loosening agent spraying device. The detachable and easily scattered parts on the spraying device strictly comply with the relevant requirements for power station foreign body prevention in structural design, making it convenient to take foreign body prevention measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic structural diagram of a reactor pressure vessel main bolt thread loosening agent spraying device provided by the present invention;

[0027] Figure 2 for Figure 1 Middle AA section view;

[0028] Figure 3 for Figure 1 Middle BB section view;

[0029] Figure 4 A schematic diagram for use in the present invention;

[0030] In the figure: 1—upper support plate, 2—support column, 3—lower support plate, 4—loading and unloading hole, 5—internal thread, 6—support adjustment member, 7—handle, 8—boss, 9—external thread, 10—support sleeve, 11—top load-bearing beam, 12—adjustable pressure block, 13—L-shaped keyway, 14—pin shaft, 15—key, 16—arc surface, 17—connecting shaft, 18—positioning plate, 9—thread loosening agent. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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 creative work are within the scope of protection of the present invention.

[0032] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] like Figure 1 As shown, the present invention provides a reactor pressure vessel main bolt thread loosening agent spraying device, the overall appearance of the cylindrical cage shape, including an upper clamping assembly, a middle support assembly, and a lower adjustment assembly.

[0035] The middle support assembly is the main structure of the entire spraying device, used to accommodate the thread loosening agent 19 and limit its radial displacement, and also serves as the gripping part when the staff holds the spraying device. The middle support assembly includes an upper support plate 1, a support column 2, and a lower support plate 3. The upper support plate 1 and the lower support plate 3 are both circular structures, and are evenly distributed with four circular through holes on the circumference near the outer edge, which are used to cooperate with the support column 2. Figure 2 As shown. A loading and unloading hole 4 is opened in the middle of the upper support plate 1, and its diameter is slightly larger than the diameter of the thread loosening agent tank body, which serves as a channel for loading and discharging the thread loosening agent tank body into and out of the device. In the middle of the lower support plate 3 is an internal threaded through hole with an internal thread 5; there are 4 support columns 2, and the upper and lower ends are respectively inserted into the evenly distributed circular through holes on the upper support plate 1 and the lower support plate 3, and are welded and fixed to form the main support assembly of the whole set of equipment.

[0036] The selection of this structural form instead of an integral cylindrical outer wall structure is to reduce the weight of the entire device to the maximum extent while satisfying the overall structural strength, while making it easier for operators to observe, rotate and adjust the direction of the thread loosening agent tank.

[0037] The lower adjustment component is located at the lower end of the middle support component, and plays the role of supporting the bottom of the thread loosening agent 19 tank and adjusting the spray flow of the thread loosening agent 19. The lower adjustment component includes a support adjustment member 6 and a handle 7. The lower part of the support adjustment plate 6 is in the shape of a circular plate, and the upper part is a boss 8. The upper end surface of the boss 8 is designed to be a spherical surface, which perfectly fits the concave surface at the bottom of the thread loosening agent 19 tank, increases the force area, and prevents the spraying device from squeezing the thread loosening agent 19 tank too much and causing the tank to rupture; the outer surface of the circular plate of the support adjustment plate 6 is processed with an external thread 9, which cooperates with the internal thread 5 of the inner circle of the lower support plate 3, so that the support adjustment member 6 can move up and down relative to the middle support component through thread rotation, realizing the opening and closing and flow adjustment of the thread loosening agent 19 spray. The thread matching provides continuous squeezing force to realize the automatic spraying of the thread loosening agent, freeing the hands of the staff and greatly reducing the burden on the staff; the handle 7 is welded to the bottom surface of the support adjustment member 6, and serves as a knob for rotating the support adjustment member 6. At the same time, the lower adjustment component is a detachable and easily scattered component on the spray device, and the spray device is used in the core area. According to the relevant requirements of the power station to prevent foreign matter, the structure of the handle 7 is convenient for tying an anti-fall rope to prevent the lower adjustment component from scattering and forming foreign matter.

[0038] The upper clamping assembly is located at the upper end of the middle support assembly, and plays the role of clamping the top nozzle of the thread loosening agent and adjusting the direction of the nozzle of the thread loosening agent 19. The upper clamping assembly includes a support sleeve 10, a top load-bearing beam 11, and an adjustable pressure block 12. The support sleeve 10 is welded to the upper surface of the upper support plate 1. It is a circular tube structure with unclosed ends, which is used to accommodate and support the top load-bearing beam 11. An L-shaped keyway 13 is machined at the upper middle part of the support sleeve 10; the top load-bearing beam 11 is used to withstand the reaction force when squeezing the nozzle of the thread loosening agent 19, and its lower pin shaft 14 is installed inside the support sleeve 10 and can rotate around the axis of the support sleeve 10. A cylindrical key 15 is machined on the outer surface of the pin shaft 14, such as Figure 3 As shown, the cylindrical key 15 cooperates with the L-shaped keyway 13 and can move freely in the keyway. When the key 15 moves in the horizontal section of the L-shaped keyway 13, the top load-bearing beam 11 can rotate, and the rotation angle is about 100°. The purpose is to move the top load-bearing beam 11 away from above the loading and unloading hole 4 to establish a channel for replacing the thread loosening agent. The spraying device is in the loading and unloading state; when the key 15 is in the vertical section of the L-shaped keyway 13, the top load-bearing beam 11 is just above the center of the loading and unloading hole 4 and is restricted from rotating, and the spraying device is in a working state.

[0039] The adjustable pressing block 12 is installed in the groove inside the top bearing beam 11 and can rotate freely around the vertical axis. The lower end surface of the adjustable pressing block 12 is a circular arc surface 16, which perfectly matches the pressing surface of the thread loosening agent 19 nozzle. The adjustable pressing block 12 is connected to the top bearing beam 11 through the connecting shaft 17 in the middle and the positioning plate 18 at the upper end. According to the changes in the on-site position, the thread loosening agent needs to change the spraying direction frequently. The adjustable design of the adjustable pressing block 12 adapts to this demand and is adjusted with the direction of the thread loosening agent nozzle, which is convenient and flexible.

[0040] like Figure 4 As shown, the installation and use method of the thread loosening agent 19 spray device is as follows:

[0041] (1) Rotate the handle 7 clockwise and counterclockwise (looking up) to check whether the support adjustment member 6 is active. Adjust the support adjustment member 6 so that the upper plane of its circular plate is flush with the upper plane of the lower support plate 3, and ensure that the head spray head of the thread loosening agent is not higher than the lower end surface of the adjustable pressing block 12 after it is loaded into the spraying device;

[0042] (2) Under the action of its own weight, the key 15 on the top bearing beam 11 is in the horizontal section of the L-shaped keyway 13. The top bearing beam 11 is rotated counterclockwise (looking down) to the bottom, so that it moves away from the loading and unloading hole 4, establishing a channel for the thread loosening agent to be loaded, and the spraying device is in the loading and unloading state;

[0043] (3) Load a can of thread loosening agent 19 into the spraying device from the loading and unloading hole 4, and adjust the direction of the spray head according to the on-site requirements. Rotate the top load-bearing beam 11 clockwise (looking down) to the bottom, and adjust the adjustable pressure block 12 to align the arc surface 16 with the concave surface on the upper end of the thread loosening agent 19 spray head. Rotate the handle 7 clockwise (looking up) to drive the support adjustment part 6 to move upward, and the concave surface on the upper end of the thread loosening agent 19 spray head contacts the arc surface 16, thereby moving the top load-bearing beam 11 upward, and the key 15 reaches the upper limit of the vertical section of the L-shaped keyway 13. The thread loosening agent 19 spray head is subjected to a slight squeezing force and stops rotating. At this time, the thread loosening agent 19 is in a waiting state, and you only need to continue to rotate the handle 7 slightly clockwise to carry out spraying;

[0044] (4) Carry out spraying according to the needs of the site, and adjust the spraying flow rate by fine-tuning the position of the support adjustment member 6. The staff only needs to hold the spraying device and aim the thread loosening agent 19 nozzle at the target position. After the thread loosening agent is sprayed, loosen the support adjustment member 6, remove the top bearing beam 11, replace the new thread loosening agent and repeat the above steps.

[0045] The present invention solves the problems existing in the previous main bolt thread loosening agent spraying process, improves the thread loosening agent spraying efficiency, fully softens the hardened molybdenum disulfide grease on the thread, avoids the abnormal event of difficulty in removing the main bolt, and reduces the total collective dosage value of the main bolt thread loosening agent spraying work. This project can be promoted and applied in related work of the same type of units.

[0046] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0047] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A reactor pressure vessel main bolt thread loosening agent spraying device, characterized in that: The spraying device comprises an upper clamping assembly, a middle support assembly, and a lower adjustment assembly. The middle support assembly is the main structure of the entire spraying device, and is used to accommodate the thread loosening agent (19) and limit its radial displacement, and is also used as a gripping part when the worker holds the spraying device. The lower adjustment assembly is located at the lower end of the middle support assembly, and plays the role of supporting the bottom of the thread loosening agent (19) tank and adjusting the spraying flow of the thread loosening agent (19). The upper clamping assembly is located at the upper end of the middle support assembly, and plays the role of clamping the top nozzle of the thread loosening agent and adjusting the direction of the nozzle of the thread loosening agent (19). The middle support assembly comprises an upper support plate (1), support columns (2), and a lower support plate (3); the upper support plate (1) and the lower support plate (3) are both annular structures, and are provided with circular through holes evenly distributed on the circumference close to the outer edge; the upper and lower ends of a plurality of support columns (2) are respectively inserted into the circular through holes evenly distributed on the upper support plate (1) and the lower support plate (3); The upper support plate (1) has a loading and unloading hole (4) in the middle, the diameter of which is slightly larger than the diameter of the thread loosening agent (19) tank body, serving as a passage for loading and discharging the thread loosening agent tank body into and out of the device; the lower support plate (3) has an internal thread through hole processed with an internal thread (5) in the middle; The lower adjustment component comprises a support adjustment member (6) and a handle (7). The lower part of the support adjustment member (6) is in the shape of a circular plate, and the upper part is a boss (8). The upper end surface of the boss (8) is designed to be a spherical surface, which perfectly matches the concave surface at the bottom of the thread loosening agent (19) tank body. The outer surface of the circular plate of the support adjustment member (6) is processed with an external thread (9), which cooperates with the internal thread (5) of the inner ring of the lower support plate (3), so that the support adjustment member (6) can move up and down relative to the middle support member by rotating the thread, thereby realizing the opening and closing of the thread loosening agent (19) spraying and flow adjustment. The handle (7) is welded to the bottom surface of the support adjustment member (6) and serves as a knob for rotating the support adjustment member (6). The upper clamping assembly comprises a support sleeve (10), a top load-bearing beam (11), and an adjustable pressure block (12); the support sleeve (10) is welded to the upper surface of the upper support plate (1) and is a circular tube structure with unclosed ends, and is used to accommodate and support the top load-bearing beam (11); the top load-bearing beam (11) is mounted on the support sleeve (10); the adjustable pressure block (12) is mounted in a groove inside the top load-bearing beam (11) and can rotate freely around a vertical axis; An L-shaped keyway (13) is machined at the upper middle portion of the support sleeve (10); the top load-bearing beam (11) is used to withstand the reaction force when squeezing the thread loosening agent (19) nozzle, and its lower pin shaft (14) is installed inside the support sleeve (10) and rotates around the axis of the support sleeve (10); a cylindrical key (15) is machined on the outer surface of the pin shaft (14), and the cylindrical key (15) cooperates with the L-shaped keyway (13) and moves freely in the keyway.

2. A reactor pressure vessel main bolt thread loosening agent spraying device according to claim 1, characterized in that: When the cylindrical key (15) moves in the horizontal section of the L-shaped key slot (13), the top load-bearing beam (11) rotates, and the maximum rotation angle is 100°; when the cylindrical key (15) is in the vertical section of the L-shaped key slot (13), the top load-bearing beam (11) is located just above the center of the loading and unloading hole (4) and is restricted from rotating, and the spraying device is in a working state.

3. A reactor pressure vessel main bolt thread loosening agent spraying device according to claim 2, characterized in that: The lower end surface of the adjustable pressing block (12) is a circular arc surface (16) which fits with the pressing surface of the thread loosening agent (19) nozzle.

4. A reactor pressure vessel main bolt thread loosening agent spraying device according to claim 3, characterized in that: The adjustable pressing block (12) is connected to the top load-bearing beam (11) via a connecting shaft (17) in the middle and a positioning plate (18) at the upper end.

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