Fireproof device for unbonded prestressed cap of nuclear power station

Abstract

The invention discloses a nuclear power station unbonded prestressed cap fireproof device, and particularly relates to the technical field of nuclear power station safety protection. The outer side of the upper portion of the fireproof cover cap body is sleeved with a protective sleeve, the fireproof cover cap body comprises a stainless steel inner layer, the outer side of the stainless steel inner layer is wrapped with a composite fiber aerogel heat insulation belt, and the outer side of the composite fiber aerogel heat insulation belt is wrapped with a flame-retardant sealing assembly. The outer side of the flame-retardant sealant assembly is wrapped with a basalt fiber fire-resistant heat-insulating belt, the outer side of the basalt fiber fire-resistant heat-insulating belt is wrapped with another group of flame-retardant sealing assembly, the outer side of the other group of flame-retardant sealing assembly is wrapped with ceramic fiber cloth, the outer side of the ceramic fiber cloth is sleeved with a stainless steel outer protective cylinder, and the outer side of the stainless steel outer protective cylinder is sleeved with a stainless steel outer protective cylinder. The flame-retardant sealing assembly comprises two groups of flame-retardant sealing adhesive tapes and a group of basalt fiber gridding cloth, and the basalt fiber gridding cloth is located between the two groups of flame-retardant sealing adhesive tapes; through the combination of all the layers in the fireproof cover cap main body, the fireproof cover cap main body can achieve the effects of fire resistance and heat insulation.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power plant safety protection, and more specifically, to a fire protection device for a non-bonded prestressed cap of a nuclear power plant. Background Art

[0002] The non-bonded prestressed cap of a nuclear power plant is a key component of the nuclear reactor containment vessel. Its mechanical properties directly affect the safety of nuclear facilities and can effectively block high temperatures in a fire environment to ensure the mechanical properties of the cap.

[0003] For example, a lithium battery cap provided by a Chinese utility model patent with the publication number CN211062753U includes a housing. A fixing ring is fixedly arranged inside the housing. A top cover is arranged inside the fixing ring. The top cover is fixedly connected to the fixing ring. A nickel sheet is arranged at the bottom of the top cover. A sealing mechanism is arranged between the nickel sheet and the top cover. By providing the sealing mechanism, the sealing mechanism between the nickel sheet and the top cover will be squeezed during encapsulation, so that the first corrugated plate and the second corrugated plate are engaged with each other and the engagement is tighter. And the sealing ring between the first corrugated plate and the second corrugated plate will be closer to the two corrugated pipes due to the extrusion between the two corrugated pipes, and the contact area between the sealing ring and the corrugated pipes can be increased. The inside can be sealed through the sealing mechanism, and the outside can be sealed through the fixing ring, so that the sealing performance of the device can be effectively improved.

[0004] In the prior art, conventional non-bonded prestressed caps lack fire resistance and flame retardancy functions. High temperatures during a fire easily cause loss of the mechanical properties of the cap, presenting potential safety hazards. And the fire resistance effect of the currently used fireproof materials is poor. Although they have a certain heat insulation property, in the closed and high-pressure environment of a nuclear power plant, they are prone to failure of the fire protection effect due to air pressure changes, thus affecting the use effect of the non-bonded prestressed cap fire protection device. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides a fire protection device for a non-bonded prestressed cap of a nuclear power plant. The technical problem to be solved by the present invention is: the problem of poor fire resistance and heat insulation effects of existing non-bonded prestressed caps of nuclear power plants.

[0006] To achieve the above object, the present invention provides the following technical solution: a fire protection device for an unbonded prestressed cap of a nuclear power plant, comprising a fire protection cap body for a nuclear power plant, a protective sleeve and a positioning assembly; the protective sleeve is slidably sleeved on the fire protection cap body through the positioning assembly; the fire protection cap body includes a stainless steel inner layer, the outer side of the stainless steel inner layer is wrapped with a composite fiber aerogel heat insulation belt, the outer side of the composite fiber aerogel heat insulation belt is wrapped with a flame retardant sealing assembly, the outer side of the flame retardant sealant assembly is wrapped with a basalt fiber fire resistant heat insulation belt, the outer side of the basalt fiber fire resistant heat insulation belt is wrapped with another group of flame retardant sealing assemblies, the outer side of the another group of flame retardant sealing assemblies is wrapped with a ceramic fiber cloth, and the outer side of the ceramic fiber cloth is sleeved with a stainless steel outer protective cylinder. The flame retardant sealing assembly includes two groups of flame retardant sealing tapes and a group of basalt fiber mesh cloth, and the basalt fiber mesh cloth is located between the two groups of flame retardant sealing tapes.

[0007] As a further solution of the present invention: the positioning assembly includes a fixed block, a rotating groove, a rotating column, a connecting plate and a positioning plate; a plurality of the fixed blocks are uniformly arranged on the fire protection cap body through a limiting assembly; a rotating groove is formed in the fixed block; the rotating column is inserted into the rotating groove; the connecting plate is fixedly arranged on the circumferential surface of the rotating column; the positioning plate is connected with the protective sleeve through a buffer assembly.

[0008] As a further solution of the present invention: the rotating column is rotatably matched with the rotating groove.

[0009] As a further solution of the present invention: the positioning assembly further includes a sliding groove and a sliding block; at least one sliding groove is formed in the rotating groove; the sliding block is inserted into the sliding groove and fixedly connected with the rotating column.

[0010] As a further solution of the present invention: the sliding block is slidably matched with the sliding groove.

[0011] As a further solution of the present invention: the sliding groove includes a rotating part and a moving part; the rotating part is a spiral structure, and the radian of the rotating part is 90-180 degrees, and the moving part is a straight groove structure.

[0012] As a further solution of the present invention: the limiting assembly includes a fixed seat, a movable groove, a movable block, a return spring, a limiting groove, a rotating plate and a limiting block; the fixed seat is fixedly arranged on the fixed block and fixedly connected with the fire protection cap body; a movable groove is formed in the fixed seat, and the end of the rotating column passes through the rotating groove and extends into the movable groove; the movable block is slidably arranged in the movable groove and rotatably connected with the rotating column through a rotating shaft; the two ends of the return spring are respectively fixedly connected with the inner wall of the movable groove and the movable block; at least one limiting groove is formed in the movable block; at least one rotating plate is rotatably arranged in the movable groove through a rotating shaft; the limiting block is slidably inserted into the limiting groove and fixedly connected with the rotating plate.

[0013] As a further solution of the present invention: the limiting groove is a heart-shaped structure, and the outer wall and the inner wall of the tip and the concave end of the limiting groove are arranged in an alternating manner, and the arc of the outer wall at the bottom edge of the limiting groove is larger than the arc of the inner wall.

[0014] As a further solution of the present invention: the buffer assembly includes a buffer groove, a buffer spring, a pressing block and a pressing groove; a buffer groove is formed on the side of the positioning plate away from the connecting plate; one end of the buffer spring is fixedly connected to the inner wall of the buffer groove; the pressing block is slidably inserted into the buffer groove and fixedly connected to the other end of the buffer spring; a plurality of pressing grooves are uniformly formed on the protective sleeve and are inserted and matched with the pressing block.

[0015] As a further solution of the present invention: the pressing block is a Y-shaped structure with a large upper part and a small lower part, and the inclined surface of the pressing block contacts the inner wall of the buffer groove.

[0016] The beneficial effects of the present invention are as follows:

[0017] 1. The present invention plays a role in fire resistance and heat insulation through multiple layers of fire-resistant heat insulation belts. The flame-retardant sealing tape bonds each layer of heat insulation belts to form an integral structure, and at the same time provides a highly tough sealing environment; the fire resistance performance of the fireproof cap body can be effectively enhanced through the ceramic fiber fireproof cloth. The temperature resistance of the ceramic fiber fireproof cloth reaches 1200 °C, which increases the resistance to flame heat radiation and thermal shock and prolongs the pyrolysis time of the structure. Through the basalt fiber fire-resistant heat insulation belt inside the ceramic fiber fireproof cloth, the temperature can be reduced from 1100 °C to 800 °C, and through the composite fiber aerogel heat insulation belt inside the basalt fiber fire-resistant heat insulation belt, the temperature can be reduced from 800 °C to 300 °C.

[0018] 2. By setting the positioning assembly in the present invention, the protective sleeve is aligned with the bottom end of the fireproof cap body through the positioning groove. Then, the rotating column is pressed downwards, so that the rotating column moves downwards in the rotating groove through the limiting assembly, the sliding block slides in the rotating part, the rotating column rotates in the rotating groove, the rotating column rotates with the movable block through the rotating shaft, the connecting plate drives the positioning plate to rotate until the sliding block slides to the junction of the rotating part and the moving part. At this time, the sliding block will slide downwards in the moving part, the connecting plate drives the positioning plate to move downwards until the positioning plate contacts the fireproof cap body through the buffer assembly, and then the protective sleeve can be fixed on the fireproof cap body quickly and conveniently with strong stability.

[0019] 3. In the present invention, by providing a limiting component, when the rotating column moves downward in the rotating groove, the movable block will slide downward in the movable groove, causing the limiting block to slide from the tip of the limiting groove to the side end of the limiting groove, enabling the rotating plate to rotate through the rotating shaft with the movable groove, and causing the return spring to contract under force until the limiting block slides to the side end of the limiting groove. At this time, when the rotating column is released, under the elastic force of the return spring, the movable block will slide upward in the movable groove, causing the limiting block to slide from the side end of the limiting groove to the concave end of the limiting groove, causing the rotating column, the connecting plate, and the positioning plate to move upward, and causing the extrusion block to slide reversely in the buffer groove until the limiting block slides to the concave end of the limiting groove, fixing the position of the rotating column in the rotating groove.

[0020] 4. In the present invention, by providing a buffer component, through the insertion of the extrusion block into the extrusion groove, not only can the protective sleeve be fixed on the fireproof cap body to conveniently fill the gap between the positioning plate and the protective sleeve, but also, through the acting force generated by the contraction of the buffer spring under force, the position of the protective sleeve on the fireproof cap body can be made more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 is a cross-sectional view of the overall structure of the present invention;

[0023] Figure 3 is a disassembled cross-sectional view of the overall structure of the present invention;

[0024] Figure 4 is a disassembled cross-sectional view of a partial structure of the present invention;

[0025] Figure 5 is a cross-sectional view of the fixed block structure of the present invention;

[0026] Figure 6 is a schematic plan view of the fixed seat structure of the present invention;

[0027] Figure 7 of the present invention Figure 2 magnified view of part A in;

[0028] Figure 8 of the present invention Figure 2 magnified view of part B in;

[0029] Figure 9 of the present invention Figure 2 magnified view of part C in.

[0030] In the figure:

[0031] 1. Fireproof cap body; 2. Protective sleeve; 3. Positioning component; 4. Limiting component; 5. Buffer component;

[0032] 301. Fixed block; 302. Rotating groove; 303. Rotating column; 304. Connecting plate; 305. Positioning plate; 306. Sliding groove; 307. Sliding block;

[0033] 3061. Rotating part; 3062. Moving part;

[0034] 401. Fixed seat; 402. Moving groove; 403. Moving block; 404. Return spring; 405. Limiting groove; 406. Rotating plate; 407. Limiting block;

[0035] 501. Buffer groove; 502. Buffer spring; 503. Extrusion block; 504. Extrusion groove. Detailed implementation manner

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0037] As Figures 1 to 9 shown, the present invention provides a fire prevention device for the unbonded prestressed cap of a nuclear power plant, including a fire prevention cap main body 1 for a nuclear power plant, a protective sleeve 2 and a positioning assembly 3; the protective sleeve 2 is slidably sleeved on the fire prevention cap main body 1 through the positioning assembly 3; the fire prevention cap main body 1 includes a stainless steel inner layer, the outside of the stainless steel inner layer is wrapped with a composite fiber aerogel heat insulation belt, the thickness of the composite fiber aerogel heat insulation belt is 3 - 6 mm, the outside of the composite fiber aerogel heat insulation belt is wrapped with a flame retardant sealing assembly, the outside of the flame retardant sealing glue assembly is wrapped with a basalt fiber fire resistance heat insulation belt, the thickness of the basalt fiber fire resistance heat insulation belt is 3 - 6 mm, the outside of the basalt fiber fire resistance heat insulation belt is wrapped with another group of flame retardant sealing assemblies, the outside of the other group of flame retardant sealing assemblies is wrapped with a ceramic fiber cloth, the thickness of the ceramic fiber fireproof cloth is 1 - 2 mm, the outside of the ceramic fiber cloth is sleeved with a stainless steel outer protective cylinder, the flame retardant sealing assembly includes two groups of flame retardant sealing tapes and a group of basalt fiber mesh cloth, and the basalt fiber mesh cloth is located between the two groups of flame retardant sealing tapes.

[0038] The present invention plays a fire-resistant and heat-insulating role through multiple layers of fire-resistant heat-insulating belts. The flame-retardant sealing tape bonds each layer of heat-insulating belts to form an integral structure, and at the same time provides a highly tough sealing environment; the refractory performance of the fire-proof cap body can be effectively enhanced through the ceramic fiber fire-proof cloth, and the temperature resistance of the ceramic fiber fire-proof cloth reaches 1200 °C, which increases the resistance to flame heat radiation and thermal shock and prolongs the pyrolysis time of the structure. Through the basalt fiber fire-resistant heat-insulating belt inside the ceramic fiber fire-proof cloth, the temperature can be reduced from 1100 °C to 800 °C, and through the composite fiber aerogel heat-insulating belt inside the basalt fiber fire-resistant heat-insulating belt, the temperature can be reduced from 800 °C to 300 °C.

[0039] As a preferred embodiment, the positioning assembly 3 includes a fixed block 301, a rotating groove 302, a rotating column 303, a connecting plate 304, a positioning plate 305, a sliding groove 306 and a sliding block 307; eight fixed blocks 301 are uniformly arranged on the fire-proof cap body 1 through the limiting assembly 4; a rotating groove 302 is formed in the fixed block 301; the rotating column 303 is arranged in the rotating groove 302; the connecting plate 304 is fixed on the circumferential surface of the rotating column 303; the positioning plate 305 is connected to the protective sleeve 2 through the buffer assembly 5; the rotating column 303 is rotationally matched with the rotating groove 302; a sliding groove 306 is formed in the rotating groove 302; the sliding block 307 is arranged in the sliding groove 306 and fixedly connected to the rotating column 303; the sliding block 307 is slidably matched with the sliding groove 306; the sliding groove 306 includes a rotating part 3061 and a moving part 3062; the rotating part 3061 is a spiral structure, and the radian of the rotating part 3061 is 90-180 degrees, and the moving part 3062 is a straight groove structure, which can not only realize the automatic steering function of the connecting plate 304 and the positioning plate 305, but also limit the position of the rotating column 303.

[0040] The present invention sets the positioning assembly 3. Align the protective sleeve 2 with the bottom end of the fire-proof cap body 1 through the positioning groove. Then, press down the rotating column 303, so that the rotating column 303 moves downward in the rotating groove 302 through the limiting assembly 4, so that the sliding block 307 slides in the rotating part 3061, and the rotating column 303 rotates in the rotating groove 302, so that the rotating column 303 rotates with the movable block 403 through the rotating shaft, so that the connecting plate 304 drives the positioning plate 305 to rotate until the sliding block 307 slides to the intersection of the rotating part 3061 and the moving part 3062. At this time, the sliding block 307 will slide downward in the moving part 3062, so that the connecting plate 304 drives the positioning plate 305 to move downward until the positioning plate 305 contacts the fire-proof cap body 1 through the buffer assembly 5, and then the protective sleeve 2 can be fixed on the fire-proof cap body 1 quickly and conveniently with strong stability.

[0041] As a preferred embodiment, the limiting component 4 includes a fixed seat 401, a movable groove 402, a movable block 403, a return spring 404, a limiting groove 405, a rotating plate 406 and a limiting block 407; the fixed seat 401 is fixedly arranged on the fixed block 301 and fixedly connected with the fireproof cap body 1; a movable groove 402 is formed in the fixed seat 401, and the end of the rotating column 303 passes through the rotating groove 302 and extends into the movable groove 402; the movable block 403 is slidably arranged in the movable groove 402 and is rotatably connected with the rotating column 303 through a rotating shaft; the two ends of the return spring 404 are respectively fixedly connected with the inner wall of the movable groove 402 and the movable block 403; two limiting grooves 405 are symmetrically formed on both sides of the movable block 403; the two rotating plates 406 are rotatably arranged on both sides of the inner wall of the movable groove 402 through a rotating axis; the limiting block 407 is slidably inserted into the limiting groove 405 and fixedly connected with the rotating plate 406; the limiting groove 405 is in a heart shape, and the outer wall and the inner wall of the tip and the concave end of the limiting groove 405 are staggered, and the outer wall arc of the bottom edge of the limiting groove 405 is larger than the inner wall arc.

[0042] In the present invention, by arranging the limiting component 4, when the rotating column 303 moves downward in the rotating groove 302, the movable block 403 will slide downward in the movable groove 402, so that the limiting block 407 slides from the tip of the limiting groove 405 to the side end of the limiting groove 405, the rotating plate 406 rotates through the rotating axis with the movable groove 402, and the return spring 404 is stressed and contracted until the limiting block 407 slides to the side end of the limiting groove 405. At this time, when the rotating column 303 is released, under the elastic force of the return spring 404, the movable block 403 will slide upward in the movable groove 402, so that the limiting block 407 slides from the side end of the limiting groove 405 to the concave end of the limiting groove 405, the rotating column 303, the connecting plate 304 and the positioning plate 305 move upward, and the extrusion block 503 slides reversely in the buffer groove 501 until the limiting block 407 slides to the concave end of the limiting groove 405, and the position of the rotating column 303 in the rotating groove 302 is fixed.

[0043] As a preferred embodiment, the buffer assembly 5 includes a buffer groove 501, a buffer spring 502, a pressing block 503, and a pressing groove 504; a buffer groove 501 is formed on the side of the positioning plate 305 away from the connecting plate 304; one end of the buffer spring 502 is fixedly connected to the inner wall of the buffer groove 501; the pressing block 503 is slidably inserted into the buffer groove 501 and fixedly connected to the other end of the buffer spring 502; eight pressing grooves 504 are uniformly formed on the protective sleeve 2 and are in plug-in fit with the pressing block 503; the pressing block 503 has a Y-shaped structure with a large upper part and a small lower part, and the inclined surface of the pressing block 503 contacts the inner wall of the buffer groove 501 to facilitate the limitation of the position of the pressing block 503; when the limiting block 407 slides to the side end of the limiting groove 405, the sliding block 307 does not contact the inner bottom wall of the moving part 3062, the connecting plate 304 does not contact the fixed seat 401, and the positioning plate 305 does not contact the protective sleeve 2; when the limiting block 407 slides to the concave end of the limiting groove 405, the pressing block 503 is still inserted into the pressing groove 504.

[0044] In the present invention, by providing the buffer assembly 5 and inserting the pressing block 503 into the pressing groove 504, not only can the protective sleeve 2 be fixed on the fireproof cap body 1 to facilitate filling the gap between the positioning plate 305 and the protective sleeve 2, but also the position of the protective sleeve 2 on the fireproof cap body 1 can be made more stable by the acting force generated by the compression of the buffer spring 502.

[0045] Working principle of the present invention: When in use, align the protective sleeve 2 with the bottom end of the fireproof cap body 1 through the positioning groove. Then, press down the rotating column 303, causing the rotating column 303 to move downward in the rotating groove 302, making the sliding block 307 slide within the rotating portion 3061, causing the rotating column 303 to rotate within the rotating groove 302, enabling the rotating column 303 to rotate with the movable block 403 through the rotating shaft, making the connecting plate 304 drive the positioning plate 305 to rotate until the sliding block 307 slides to the junction of the rotating portion 3061 and the moving portion 3062. At this time, the sliding block 307 will slide downward within the moving portion 3062, causing the connecting plate 304 to drive the positioning plate 305 to move downward. Moreover, when the rotating column 303 moves downward within the rotating groove 302, the movable block 403 will slide downward within the movable groove 402, causing the limiting block 407 to slide from the tip of the limiting groove 405 to the side end of the limiting groove 405, making the rotating plate 406 rotate with the movable groove 402 through the rotating shaft, causing the return spring 404 to contract under force until the bottom surface of the extrusion block 503 contacts the inner bottom wall of the extrusion groove 504. At this time, the extrusion block 503 will slide within the buffer groove 501, causing the buffer spring 502 to contract under force until the limiting block 407 slides to the side end of the limiting groove 405. At this time, release the rotating column 303. Under the elastic force of the return spring 404, the movable block 403 will slide upward within the movable groove 402, causing the limiting block 407 to slide from the side end of the limiting groove 405 to the concave end of the limiting groove 405, making the rotating column 303, the connecting plate 304, and the positioning plate 305 move upward, causing the extrusion block 503 to slide reversely within the buffer groove 501 until the limiting block 407 slides to the concave end of the limiting groove 405. At this time, since the extrusion block 503 is inserted into the extrusion groove 504, the protective sleeve 2 can be fixed on the fireproof cap body 1. And, through the acting force generated by the contraction of the buffer spring 502 under force, the position of the protective sleeve 2 on the fireproof cap body 1 can be made more stable. When disassembling, press down the rotating column 303, causing the limiting block 407 to slide from the concave end of the limiting groove 405 to the other side end of the limiting groove 405, making the rotating column 303, the connecting plate 304, and the positioning plate 305 move downward until the limiting block 407 slides to the other side end of the limiting groove 405. At this time, release the rotating column 303. Under the elastic force of the return spring 404, the extrusion block 503 will fall off from the inserted extrusion groove 504, and the rotating column 303, the connecting plate 304, and the positioning plate 305 will rotate to their original positions, and then the protective sleeve 2 can be removed from the fireproof cap body 1.

[0046] The following points should be noted: First, in the description of this application, it should be noted that unless otherwise specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense, which can be a mechanical connection or an electrical connection, or the communication inside two components, and can be directly connected. The terms "upper", "lower", "left", "right", etc. are only used to represent relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may change;

[0047] Second, in the drawings of the disclosed embodiments of the present invention, only the structures related to the disclosed embodiments are involved. Other structures can refer to the general design. Without conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0048] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, should be covered by the protection scope of the present invention.

Claims

1. A fire protection device for the unbonded prestressed cap of a nuclear power plant, characterized in that, It includes a fireproof cap body (1), a protective sleeve (2) and a positioning component (3) for a nuclear power plant; the protective sleeve (2) is slidably sleeved on the fireproof cap body (1) through the positioning component (3); The fireproof cap body (1) includes a stainless steel inner layer, the outside of the stainless steel inner layer is wrapped with a composite fiber aerogel heat insulation belt, the outside of the composite fiber aerogel heat insulation belt is wrapped with a flame retardant sealing component, the outside of the flame retardant sealant component is wrapped with a basalt fiber fireproof heat insulation belt, the outside of the basalt fiber fireproof heat insulation belt is wrapped with another group of flame retardant sealing components, the outside of the another group of flame retardant sealing components is wrapped with a ceramic fiber cloth, the outside of the ceramic fiber cloth is sleeved with a stainless steel outer protective cylinder, the flame retardant sealing component includes two groups of flame retardant sealing tapes and a group of basalt fiber mesh cloth, and the basalt fiber mesh cloth is located between the two groups of flame retardant sealing tapes.

2. The fire protection device for the unbonded prestressed cap of a nuclear power plant according to claim 1, wherein The positioning component (3) includes a fixed block (301), a rotating groove (302), a rotating column (303), a connecting plate (304) and a positioning plate (305); several fixed blocks (301) are uniformly arranged on the fireproof cap body (1) through a limiting component (4); a rotating groove (302) is opened in the fixed block (301); the rotating column (303) is inserted into the rotating groove (302); the connecting plate (304) is fixed on the circumferential surface of the rotating column (303); the positioning plate (305) is connected with the protective sleeve (2) through a buffer component (5).

3. The fire protection device for the unbonded prestressed cap of a nuclear power plant according to claim 2, wherein, The rotating column (303) is rotationally matched with the rotating groove (302).

4. The fire protection device for the unbonded prestressed cap of a nuclear power plant according to claim 3, characterized in that The positioning component (3) further includes a sliding groove (306) and a sliding block (307); at least one sliding groove (306) is opened in the rotating groove (302); the sliding block (307) is inserted into the sliding groove (306) and fixedly connected with the rotating column (303).

5. The fire protection device for the unbonded prestressed cap of a nuclear power plant according to claim 4, characterized in that, The sliding block (307) is slidably matched with the sliding groove (306).

6. The fire protection device for the unbonded prestressed cap of a nuclear power plant according to claim 5, characterized in that, The sliding groove (306) includes a rotating part (3061) and a moving part (3062); the rotating part (3061) is a spiral structure, and the radian of the rotating part (3061) is 90 - 180 degrees, and the moving part (3062) is a straight groove structure.

7. A fire protection device for the unbonded prestressed cap of a nuclear power plant according to claim 5, characterized in that, The limiting component (4) includes a fixed seat (401), a movable groove (402), a movable block (403), a return spring (404), a limiting groove (405), a rotating plate (406) and a limiting block (407); the fixed seat (401) is fixedly arranged on the fixed block (301) and fixedly connected with the fireproof cap body (1); a movable groove (402) is formed in the fixed seat (401), and the end of the rotating column (303) passes through the rotating groove (302) and extends into the movable groove (402); the movable block (403) is slidably arranged in the movable groove (402) and is rotatably connected with the rotating column (303) through a rotating shaft; the two ends of the return spring (404) are respectively fixedly connected with the inner wall of the movable groove (402) and the movable block (403); at least one limiting groove (405) is formed in the movable block (403); at least one rotating plate (406) is rotatably arranged in the movable groove (402) through a rotating shaft; the limiting block (407) is slidably inserted into the limiting groove (405) and is fixedly connected with the rotating plate (406).

8. A fire protection device for the unbonded prestressed cap of a nuclear power plant according to claim 7, characterized in that, The limiting groove (405) is in a heart shape, and the outer wall and the inner wall of the tip and the concave end of the limiting groove (405) are staggered, and the outer wall arc of the bottom edge of the limiting groove (405) is larger than the inner wall arc.

9. The fire protection device for the unbonded prestressed cap of a nuclear power plant according to claim 2, wherein The buffering component (5) includes a buffering groove (501), a buffering spring (502), a pressing block (503) and a pressing groove (504); a buffering groove (501) is formed on one side of the positioning plate (305) away from the connecting plate (304); one end of the buffering spring (502) is fixedly connected with the inner wall of the buffering groove (501); the pressing block (503) is slidably inserted into the buffering groove (501) and is fixedly connected with the other end of the buffering spring (502); a plurality of pressing grooves (504) are uniformly formed on the protective sleeve (2) and are in plug-in fit with the pressing block (503).

10. A fire protection device for the unbonded prestressed cap of a nuclear power plant according to claim 9, characterized in that, The pressing block (503) is in a Y-shaped structure with a large upper part and a small lower part, and the inclined surface of the pressing block (503) is in contact with the inner wall of the buffering groove (501).

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