A pipe flange retention structure and a retention method for a nuclear power blasting valve

Abstract

The present invention relates to the technical field of nuclear power blast valve maintenance, and more specifically to a pipe flange retention structure and a retention method for a nuclear power blast valve. Among them, a pipe flange retention structure for a nuclear power blast valve includes a support seat provided with an installation hole for a pipe to pass through, and the aperture of the installation hole is larger than the outer diameter of the pipe, so as to form a gap between the pipe and the support seat; the support seat is arranged close to the pipe flange fixedly connected to the end of the pipe; it further includes: a retention device, one end of which abuts against the support seat and the other end abuts against the pipe and is installed in the gap, and a plurality of retention devices distributed at intervals around the outer circumference of the pipe together constitute a clamping and positioning structure acting on the pipe; the retention device is detachable relative to the support seat. The preferred pipe flange retention structure of the present invention fixes the positions of the pipe flanges before and after the disassembly of the blast valve, reduces the centering adjustment time during the reinstallation of the blast valve, thereby shortening the reinstallation time of the blast valve and reducing the radiation dose of the working group members.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power blast valve maintenance, and more specifically to a pipe flange retention structure and a retention method for a nuclear power blast valve. Background Art

[0002] A total of 12 blast valves are adopted in the AP1000 nuclear power plant, including 4 14-inch blast valves on the pipeline of the fourth stage of the automatic pressure relief system, 4 8-inch blast valves on the injection pipeline of the in-containment refueling water storage tank, and 4 8-inch blast valves on the in-containment recirculation pipeline. Among them, the blast valve is a proprietary valve for AP1000 nuclear power technology, with high reliability of low pressure drop and no leakage. When the blast valve operates normally without operation, there is no leakage. When an accident occurs in the system, it receives an opening signal, and the blast valve on the pipeline of the fourth stage of the automatic pressure relief system opens to fully depressurize the primary loop, providing conditions for the gravity injection of the in-containment refueling water storage tank in the next step. After the blast valve on the gravity injection pipeline of the in-containment refueling water storage tank is opened, gravity water replenishment from the in-containment refueling water storage tank to the reactor core can be realized. During the long-term operation stage after the accident, the blast valve on the in-containment recirculation pipeline is opened to achieve long-term cooling of the reactor core.

[0003] According to the requirements of the surveillance test and the in-service test, one blast valve of each category needs to be disassembled and inspected separately during each refueling cycle to verify whether the functions of the blast valves on each system pipeline are normal. During the inspection, it is necessary to disassemble the pipe flanges connected to both ends of the blast valve, and then move the blast valve body to a predetermined position for inspection. The pipe flanges connected to the pipe ends after disassembly will drop vertically towards the ground under the action of gravity. When it is necessary to reinstall the blast valve body, the operator needs to lift and pull the dropped and misaligned pipe flanges for centering installation, and then fix them on the blast valve body. Due to the large size and weight of the pipe flange, the operator needs to spend a lot of physical strength and a long time to center and install the pipe flange. The longer the time taken for reinstalling the blast valve, the more radiation dose the working group members will receive, and the greater the safety hazard. Summary of the Invention

[0004] The purpose of the present invention is to provide a pipe flange retention structure for a nuclear power blast valve in view of the deficiencies of the prior art. By fixing the positions of the pipe flanges before and after the disassembly of the blast valve, the centering adjustment time during the reinstallation of the blast valve is reduced, thereby shortening the time taken for reinstalling the blast valve and reducing the radiation dose of the working group members. And a pipe flange retention method for a nuclear power blast valve is provided.

[0005] The technical solution of the present invention is as follows:

[0006] A pipe flange retention structure for a nuclear power blast valve, comprising:

[0007] The support base is provided with an installation hole for the pipeline to pass through, and the aperture of the installation hole is larger than the outer diameter of the pipeline, so as to form a gap between the pipeline and the support base;

[0008] The support base is arranged close to the pipeline flange fixedly connected to the end of the pipeline;

[0009] It further includes:

[0010] The retaining device is installed in the gap with one end pressing against the support base and the other end pressing against the pipeline. A plurality of the retaining devices distributed at intervals around the outer circumference of the pipeline together form a clamping and positioning structure acting on the pipeline; and the retaining device is detachable relative to the support base.

[0011] Further as a preferred solution, the retaining device includes:

[0012] The first wedge block is inserted into one end of the gap with one end face pressing against the support base and the other end face pressing against the pipeline, and the surface in contact with the support base is inclined, which is the first guiding surface for guiding the first wedge block into the gap;

[0013] The second wedge block is inserted into the other end of the gap with one end face pressing against the support base and the other end face pressing against the pipeline, and the surface in contact with the support base is inclined, which is the second guiding surface for guiding the second wedge block into the gap.

[0014] Further as a preferred solution, the retaining device further includes:

[0015] The connecting rod member has one end connected to the first wedge block; the other end passes through the second wedge block, and a fastening nut is screwed on this end. By turning the fastening nut, the movable distance between the first wedge block and the second wedge block can be reduced or lengthened.

[0016] Further as a preferred solution, the connecting rod member is screwed on the first wedge block.

[0017] Further as a preferred solution, the surfaces of the first wedge block in contact with the pipeline and the second wedge block in contact with the pipeline are both arc surfaces adapted to the outer contour surface of the pipeline.

[0018] Further as a preferred solution, the retaining device further includes:

[0019] The protective plate has one end face provided with an arc surface adapted to the outer contour of the pipeline and attached to the pipeline; a sliding rail part is arranged on the other end face. The first wedge block and the second wedge block are both slidably connected to the sliding rail part, and the first wedge block and the second wedge block press against the pipeline through the protective plate.

[0020] Further as an optimal solution, a protective pad is installed on the protective plate, and the protective plate acts on the pipeline through the protective pad.

[0021] Further as an optimal solution, there are four retention devices, and the four retention devices are distributed around the pipeline at equal intervals.

[0022] A method for retaining the pipeline flange of a nuclear power blasting valve, the steps include:

[0023] S1: Before disassembling the blasting valve body, move the support seat to a position close to the pipeline flange;

[0024] S2: Install a number of retention devices at intervals in the gap formed between the pipeline and the support seat to form a clamping and positioning structure acting on the pipeline;

[0025] S3: Complete the disassembly between the blasting valve body and the pipeline flange, so that the pipeline flange is retained on the support seat.

[0026] Further as an optimal solution, after completing step S3, it is necessary to measure two spaced and aligned pipeline flanges with a measuring tool, and adjust the position of the pipeline flange through the retention device.

[0027] The main beneficial effects of the above technical solutions are as follows:

[0028] 1. Before disassembling the blasting valve body, a clamping and positioning structure acting on the pipeline is formed through the retention device to keep the position of the pipeline flange unchanged before and after disassembling the blasting valve body, which is convenient for quickly aligning and connecting the pipeline flange to the blasting valve body more quickly when reinstalling the blasting valve later, reducing the reinstallation time and reducing the radiation dose of the work team members.

[0029] 2. Combining the installation environment of the blasting valve, the retention device is detachably fixed in the gap between the support seat and the pipeline. In this way, when the system is working normally, the support seat serves as a limit protection structure for the pipeline, and when maintenance and disassembly are required, it serves as a support structure for the retention device, without the need to additionally set up other support structures. The functionality of the support seat is increased, and the maintenance cost is reduced.

[0030] 3. The first wedge block and the second wedge block are used to press the pipeline simultaneously to improve the clamping stability of the pipeline.

[0031] 4. One end of the connecting rod member is screwed onto the first wedge block, and the other end passes through the second wedge block and is screwed with a fastening nut, which facilitates the installation of the retention device in the gap or the removal from the gap. At the same time, by turning the fastening nut, the pressing effect on the pipeline can be adjusted, facilitating subsequent adjustment of the pipeline positioning. Moreover, the threaded structure can maintain a stable pressing effect.

[0032] 5. The first wedge block and the second wedge block are both slidably connected to the protective plate and act on the pipeline through the protective plate; in this way, on the one hand, it avoids the sliding wedge block from scratching and damaging the pipeline; on the other hand, it increases the acting area on the pipeline, avoids stress concentration, and increases the clamping area on the pipeline to improve the stability of the clamping effect on the pipeline; in addition, the slide rail part also guides the wedge block, enabling the first wedge block and the second wedge block to be more smoothly inserted into the gap by turning the fastening nut, avoiding deviation, and thus being able to exert a stable pressing effect on the pipeline.

[0033] 6. A protective pad is provided, which can improve the protection effect on the pipeline; at the same time, as the protective pad adopts a rubber pad structure with a high friction coefficient as described below, it can increase the friction with the outer wall of the pipeline to improve the stability of clamping the pipeline.

[0034] 7. The four retention devices are evenly distributed around the pipeline, and can provide pressing force on the pipeline from four directions to stably clamp the pipeline.

[0035] Further or more detailed beneficial effects will be described in combination with specific embodiments in the specific implementation manner. Brief Description of the Drawings

[0036] The following further describes the present invention with reference to the drawings:

[0037] Figure 1 It is a schematic structural diagram of the retention device.

[0038] Figure 2 It is a schematic assembly diagram of the blasting valve body.

[0039] Figure 3 It is a schematic installation diagram of the protective plate.

[0040] Figure 4 It is a schematic structural diagram of the protective plate.

[0041] Figure 5 It is a schematic side installation diagram of the retention device.

[0042] Figure 6 It is a schematic structural diagram of a measuring tool.

[0043] As shown in the figure: gap x, support base 1, pipe 2, pipe flange 3, first wedge block a1, first guiding surface a101, second wedge block a2, second guiding surface a201, connecting rod member a3, fastening nut a4, protective plate a5, slide rail portion a501, blasting valve body 4, straightedge b1, first measuring ruler b2, first reading pointer b201, second measuring ruler b3, second reading pointer b301. Specific embodiments

[0044] The following are only the preferred embodiments of the present invention and do not limit the scope of the present invention. Additionally, in the embodiments of the present invention, terms such as "vertical", "horizontal", "front", "rear", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product is habitually placed during use. These are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. It should be further noted that unless otherwise clearly specified and limited, terms such as "installation", "connection", "attachment", "fixation", etc. in the description should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium, or a communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] When the blasting valve body 4 needs to be disassembled and repaired, the pipe flange 3 connected to the end of the pipe 2 after disassembly drops vertically towards the ground under the action of gravity. When the blasting valve body 4 needs to be reinstalled, the operator needs to spend a large amount of time and effort to align the pipe flange 3 with the inlet and outlet of the blasting valve body 4. Since there are irradiated substances in the blasting valve body 4, the longer the reinstallation time of the blasting valve, the more irradiated dose the working group members receive, and the greater the safety hazard.

[0046] To solve the above problems, the inventor proposed a technical solution to fix the position of the pipe flange 3 before disassembling the blasting valve body 4, that is, to keep the position of the pipe flange 3 consistent before and after the disassembly of the blasting valve body 4. In this way, when the blasting valve body 4 is reinstalled, the pipe flange 3 can be more conveniently and quickly connected in position to the blasting valve body 4 to reduce the reinstallation time, thereby reducing the irradiated dose received by the working group members.

[0047] To implement the above technical solution, the inventor studied the installation environment of the blasting valve body 4 and found that: on the blasting valve pipeline of the AP1000 nuclear power plant, as shown in the appendix Figure 2As shown, pipes 2 are connected to both the inlet and outlet of the blasting valve body 4. Pipe flanges 3 are fixedly connected to the ends of the pipes 2 for adaptively and fixedly connecting with the inlet and outlet of the blasting valve body 4. At the same time, since the pipes 2 are long and large in size, the pipes 2 will vibrate to a certain extent during normal operation. To prevent the pipes 2 from moving with large displacements and to prevent the pipes 2 from directly falling to the ground in case of connection failures, a number of support seats 1 are arranged along the extension direction of the pipes 2 as a limiting and protective structure for the pipes 2. Specifically, the support seats 1 are provided with mounting holes through which the pipes 2 pass, and the aperture of the mounting holes is larger than the outer diameter of the pipes 2, so as to form a gap x between the pipes 2 and the support seats 1. This gap x is used to accommodate a certain degree of vibration of the pipes 2 and limit the amplitude of the vibration.

[0048] Based on this, the inventor proposes a pipe flange fixation structure based on the installation environment of the blasting valve body 4. The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0049] Embodiment 1, as shown in the attached Figure 1 and the attached Figure 2 As shown, a support seat 1 is arranged close to the pipe flange 3 fixedly connected to the end of the pipe 2, and a detachable fixation device is installed in the gap x between the support seat 1 and the pipe 2; specifically, one end of the fixation device presses against the support seat 1 and the other end presses against the pipe 2 and is installed in the gap x. A number of fixation devices distributed at intervals around the outer circumference of the pipe 2 together form a clamping and positioning structure acting on the pipe 2; specifically, in this embodiment, it is preferably as shown in the attached Figure 5 As shown, there are four fixation devices, and the four fixation devices are distributed around the pipe 2 at equal intervals; that is, the circumferential intervals between any two adjacent fixation devices around the pipe 2 are preferably equal. In this way, the four fixation devices are distributed around the pipe 2 at equal intervals, and can evenly provide pressing force on the pipe 2 from the directions of the four corners of a regular quadrilateral to stably clamp the pipe 2. And the fixation device is detachable relative to the support seat 1, that is, the fixation device can be disassembled from the gap x. Among them, the fixation device can be a rubber plug or a hard plug that fits the size of the gap x and is directly filled in the gap x. However, the plug cannot adjust the pressing effect on the pipe 2 in real time. Therefore, the fixation device shown in the attached Figure 1 is proposed in this embodiment.

[0050] Specifically, the fixation device in this embodiment includes a first wedge block a1 and a second wedge block a2, where:

[0051] One end face of the first wedge block a1 presses against the support seat 1 and the other end face presses against the pipe 2 and is inserted into one end of the gap x, and the surface in contact with the support seat 1 is an inclined first guiding surface a101 that guides the first wedge block a1 into the gap x.

[0052] One end face of the second wedge block a2 abuts against the support base 1, and the other end face abuts against the pipeline 2. The second wedge block a2 is inserted into the other end of the gap x, and the surface thereof in contact with the support base 1 is an inclined second guiding surface a201 for guiding the second wedge block a2 into the gap x.

[0053] In this way, the first wedge block a1 and the second wedge block a2 can be directly pushed into the gap x from both ends of the gap x to press and clamp the pipeline 2. By controlling the depth of insertion, the pressing strength on the pipeline 2 can be controlled, and the displacement of the pipeline 2 pushed by pressing the pipeline 2 can be adjusted.

[0054] In order to improve the stability of the pressing of the first wedge block a1 and the second wedge block a2 on the pipeline 2 and prevent the first wedge block a1 and the second wedge block a2 from falling off from the gap x, in this embodiment, the retaining device further includes a connecting rod member a3. One end of the connecting rod member a3 is connected to the first wedge block a1; the other end passes through the second wedge block a2, and a fastening nut a4 is screwed on this end. By turning the fastening nut a4, the movable distance between the first wedge block a1 and the second wedge block a2 can be reduced or increased. Specifically, as shown in the appendix Figure 1 As shown, turning the fastening nut a4 to the left can insert the first wedge block a1 and the second wedge block a2 into the gap x simultaneously to press the pipeline 2 downward. By adjusting the degree of turning, the depth of insertion of the first wedge block a1 and the second wedge block a2 into the gap x can be adjusted, so as to adjust the amount of displacement of the pipeline 2 caused by pressing. At the same time, by adjusting a number of retaining devices distributed around the outer circumference of the pipeline 2 at intervals, the specific fixed position of the pipeline 2 can be adjusted. When the fastening nut a4 is turned to the right, the first wedge block a1 and the second wedge block a2 can be disengaged from the gap x for disassembly.

[0055] Furthermore, in this embodiment, the connecting rod member a3 is screwed to the first wedge block a1. In this way, the retaining device can be better disassembled, which is convenient for storage and installation, and can avoid the situation where the connecting rod member a3 connected to the first wedge block a1 cannot be smoothly inserted into the gap x due to the interference of the first wedge block a1 in a narrow position.

[0056] Certainly, in order for the wedge block to have a better pressing effect on the pipeline 2, the surface of the first wedge block a1 in contact with the pipeline 2 and the surface of the second wedge block a2 in contact with the pipeline 2 are both arc surfaces adapted to the outer contour surface of the pipeline 2.

[0057] However, during actual operation, the moving wedge block is likely to scratch the pipeline 2 during the process of inserting into the gap x and is also likely to shift during the insertion process. Therefore, in this embodiment, a protective plate a5 removably placed on the outer side surface of the pipeline 2 is further included. Specifically, as shown in the appendix Figure 3 and appendix Figure 4As shown, one end face of the protective plate a5 is an arc surface adapted to the outer contour of the pipeline 2 and attached to the pipeline 2; on the other end face, there is a slide rail part a501. The first wedge block a1 and the second wedge block a2 are respectively slidably connected to the slide rail part a501 from both sides of the slide rail part a501. The sliding direction conforms to the moving direction of the wedge block on the connecting rod member a3, and the first wedge block a1 and the second wedge block a2 act on the pipeline 2 through the pressing of the protective plate a5. In this way, both the first wedge block a1 and the second wedge block a2 are slidably connected to the protective plate a5 and act on the pipeline 2 through the pressing of the protective plate a5. In this way, on the one hand, the position of the sliding damage is transferred to the protective plate a5 to avoid scratching damage to the pipeline 2 caused by the sliding wedge block; on the other hand, compared with a single wedge block directly acting on the pipeline 2, the way of acting on the pipeline 2 through the protective plate a5 increases the acting area on the pipeline 2, avoids stress concentration, and increases the clamping area on the pipeline 2 to improve the stability of the clamping action on the pipeline 2. In addition, the slide rail part a501 also guides the wedge block, so that the first wedge block and the second wedge block can be more smoothly inserted into the gap by screwing the fastening nut, avoiding deviation, and thus being able to exert a stable pressing action on the pipeline.

[0058] Certainly, in order to further improve the protection effect on the pipeline 2, in this embodiment, a protective pad is installed on the side of the protective plate a5 facing the pipeline 2, and the protective plate a5 acts on the pipeline 2 through the protective pad; at the same time, the protective pad is preferably a rubber pad structure with a high friction coefficient, which can increase the friction with the outer wall of the pipeline 2 to improve the stability of the clamping of the pipeline 2.

[0059] Embodiment 2, a method for fixing the pipeline flange of a nuclear power blasting valve, the steps include:

[0060] S1: Before disassembling the blasting valve body 4, move the support seat 1 to a position close to the pipeline flange 3. Of course, this close distance needs to be set according to the actual scenario. If it is too far, even if the pipeline 2 is fixed on the support seat 1, it is difficult to fix the pipeline flange 3; if it is too close, it is easy to collide with and interfere with the pipeline flange 3. Therefore, on the premise that the fixing device can be installed on the support seat 1, the closer the support seat 1 is to the pipeline flange 3, the more stable the fixing of the pipeline flange 3 can be.

[0061] S2: Install a number of fixing devices at intervals in the gap x formed between the pipeline 2 and the support seat 1 to form a clamping and positioning structure acting on the pipeline 2.

[0062] S3: Complete the disassembly between the blasting valve body 4 and the pipeline flange 3, and fix the pipeline flange 3 on the support seat 1.

[0063] It should be further noted that in order to confirm whether the disassembly of the bursting valve body 4 interferes with the pipeline flange 3, after completing step S3 in this embodiment, it is necessary to measure two aligned pipeline flanges 3 at intervals with a measuring tool, mainly measuring the opening condition between the pipeline flanges 3 and the coaxiality condition of the pipeline flanges 3, and adjusting the position of the pipeline flanges 3 through the retaining device. Specifically, as described above, the position is adjusted by turning the fastening nut a4 of the retaining device at different positions, which will not be elaborated here. In this way, further confirmation and adjustment of the position of the pipeline flange 3 before reinstalling the bursting valve can further shorten the reinstallation time of the bursting valve and reduce the radiation dose of the work team members.

[0064] In this embodiment, mainly through the Figure 6 measuring ruler assembly shown in the appendix to measure the opening condition and coaxiality condition.

[0065] Specifically, as shown in the Figure 6 appendix, the measuring ruler assembly includes a straight ruler b1 with readings engraved on the edge, a first measuring ruler b2 and a second measuring ruler b3 that are slidably connected to the straight ruler b1 and perpendicular to the straight ruler b1; the first measuring ruler b2 and the second measuring ruler b3 are arranged at intervals, and a first reading pointer b201 is provided on the part of the first measuring ruler b2 that is slidably connected to the straight ruler b1 for cooperating with reading the readings on the straight ruler b1; a second reading pointer b301 is provided on the part of the second measuring ruler b3 that is slidably connected to the straight ruler b1 for cooperating with reading the readings on the straight ruler b1.

[0066] When measuring the opening condition, as shown in the Figure 6 appendix, the left end face of the first measuring ruler b2 and the right end face of the second measuring ruler b3 are parallel. By fitting the left end face of the first measuring ruler b2 to the right end face of the left pipeline flange 3, and then moving the second measuring ruler b3 to fit the left end face of the right pipeline flange 3, check whether there is a gap between the second measuring ruler b3 and the left end face of the right pipeline flange 3. If there is no gap, it means that there is no opening between the two spaced pipeline flanges 3. If there is a gap, it is necessary to adjust the position of the pipeline flange 3 through the retaining device according to the size of the gap until there is no gap.

[0067] When measuring the coaxiality condition, as shown in the Figure 6 appendix, place the straight ruler b1 horizontally on the top of the pipeline flange 3. Vertical intervals of readings are provided on the left end face of the first measuring ruler b2 and the right end face of the second measuring ruler b3. Check whether the readings of the top of the left pipeline flange 3 on the first measuring ruler b2 are the same as the readings of the top of the right pipeline flange 3 on the second measuring ruler b3. If they are different, it is necessary to adjust the position of the pipeline flange 3 through the retaining device according to the reading difference until the readings are the same.

[0068] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A pipe flange retention structure for a nuclear power blasting valve, comprising: Support seat (1), provided with a mounting hole for a pipeline (2) to pass through, and the aperture of the mounting hole is larger than the outer diameter of the pipeline (2), so as to form a gap (x) between the pipeline (2) and the support seat (1); It is characterized in that: The support seat (1) is arranged close to the pipeline flange (3) fixedly connected to the end of the pipeline (2); It further includes: A retention device, one end of which presses against the support seat (1) and the other end presses against the pipeline (2), and is installed in the gap (x). A plurality of the retention devices distributed at intervals around the outer circumference of the pipeline (2) together constitute a clamping and positioning structure acting on the pipeline (2); And the retention device is detachable relative to the support seat (1); The retention device includes: A first wedge block (a1), one end face of which presses against the support seat (1) and the other end face presses against the pipeline (2), and is inserted into one end of the gap (x). The surface in contact with the support seat (1) is inclined, and is a first guiding surface (a101) for guiding the first wedge block (a1) into the gap (x); A second wedge block (a2), one end face of which presses against the support seat (1) and the other end face presses against the pipeline (2), and is inserted into the other end of the gap (x). The surface in contact with the support seat (1) is inclined, and is a second guiding surface (a201) for guiding the second wedge block (a2) into the gap (x); The retention device further includes: A connecting rod member (a3), one end of which is connected to the first wedge block (a1); the other end passes through the second wedge block (a2), and a fastening nut (a4) is screwed on the other end. By turning the fastening nut (a4), the movable distance between the first wedge block (a1) and the second wedge block (a2) is reduced or lengthened; The connecting rod member (a3) is screwed on the first wedge block (a1); The retention device further includes: A protection plate (a5), one end face of which is arranged to fit the outer contour of the pipeline (2) and is an arc surface that fits on the pipeline (2); A slide rail part (a501) is arranged on the other end face. Both the first wedge block (a1) and the second wedge block (a2) are slidably connected to the slide rail part (a501) in a fitting manner, and the first wedge block (a1) and the second wedge block (a2) act on the pipeline (2) by pressing through the protection plate (a5).

2. The pipe flange retention structure for a nuclear power blasting valve according to claim 1, characterized in that: The surfaces of the first wedge block (a1) and the second wedge block (a2) that are in contact with the pipeline (2) are both arc surfaces that fit the outer contour surface of the pipeline (2).

3. The pipe flange retention structure for a nuclear power blasting valve according to claim 1, characterized in that: A protection pad is installed on the protection plate (a5), and the protection plate (a5) acts on the pipeline (2) through the protection pad.

4. The pipe flange retention structure for a nuclear power blasting valve according to claim 1, characterized in that: There are four retention devices, and the four retention devices are distributed around the pipeline (2) at equal intervals.

5. A pipe flange retention method applicable to the pipe flange retention structure of the nuclear power blasting valve in claim 1, characterized in that: steps It includes: S1: Before disassembling the blasting valve body (4), move the support seat (1) to a position close to the pipeline flange (3); S2: Install a number of retention devices at intervals in the gap (x) formed between the pipeline (2) and the support base (1) to form a clamping and positioning structure acting on the pipeline (2); S3: Complete the disassembly between the blasting valve body (4) and the pipeline flange (3), and fix the pipeline flange (3) on the support base (1).

6. The pipe flange retention method according to claim 5, characterized in that: After completing step S3, it is necessary to measure two aligned pipeline flanges (3) at intervals with a measuring tool, and adjust the position of the pipeline flange (3) through the retention device.

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