A thermal barrier assembly for a magnetic lifting type control rod drive mechanism

Abstract

The application belongs to the technical field of control rod drive mechanism, and particularly relates to a heat insulation sleeve assembly of a magnetic lifting type control rod drive mechanism. The heat insulation sleeve assembly comprises a pipe base, a guide sleeve and a guide cover. The upper part of the pipe base is a first end, and the lower part is a second end. The radial dimension of the first end is larger than that of the second end. The lower part of the second end is provided with a first connecting end, and the guide sleeve is fixedly connected with the first connecting end of the pipe base. The upper part of the guide cover is provided with a fourth connecting end, and the lower part is provided with a horn cover. The fourth connecting end of the guide cover is fixedly connected with the second fixed end of the guide sleeve. The heat insulation sleeve assembly of the application is in a fixed state, and the problem of active wear of the heat insulation sleeve assembly is solved from the root.

Description

Technical Field

[0001] This invention belongs to the technical field of control rod drive mechanism, specifically relating to a heat insulation sleeve assembly of a magnetic lifting control rod drive mechanism. Background Technology

[0002] The drive mechanism is a servo mechanism in the reactor control and protection system. It moves the control rods up and down according to given commands, thereby enabling reactor startup, power regulation, power maintenance, and normal and emergency shutdown. The heat shield assembly, as a functional component of the drive mechanism, typically consists of a heat shield and a guide shield. During operation, due to the high temperature of the liquid inside the pressure vessel and the low temperature of the coolant inside the drive mechanism, natural convection heat transfer occurs between the two liquids. This process is called "thermosiphon convection," and it is the main cause of wear on the heat shield assembly. To improve the lifespan of the drive mechanism, this phenomenon usually needs to be suppressed. The heat shield assembly reduces the gap between the drive mechanism and the sealing shell and increases the resistance to fluid flow from the pressure vessel to the drive mechanism, significantly suppressing thermosiphon convection. In addition, the heat shield assembly also reduces the temperature difference between the inside and outside of the tube seat wall, squeezes water upwards during rod drop, and guides the drive rod assembly into the control rod drive mechanism.

[0003] Currently, contact wear occurs between the end of the heat shield assembly and the sealing shell under the action of cooling bypass. After a certain degree of wear, the heat shield may break and detach, leading to rod jamming accidents. Chinese utility model patent CN219349804U discloses a reactor guide heat shield that is easy to replace. It uses a compensation section (i.e., a pad) to provide auxiliary support for the heat shield and prevent it from detaching. Chinese invention patent CN117476255A discloses a maintenance and replacement type heat shield for a control rod drive mechanism. The heat shield is separated from the tube seat and connected by a support seat and an installation nozzle, making the heat shield easier to replace.

[0004] However, in the two technical solutions mentioned above, the heat insulation sleeve is still in an active state, which does not fundamentally solve the technical problem of heat insulation sleeve wear. Summary of the Invention

[0005] The purpose of this invention is to provide a heat insulation sleeve assembly for a magnetic lifting control rod drive mechanism, which can solve the technical problem that the heat insulation sleeve assembly is prone to wear during the operation of the drive mechanism in the prior art.

[0006] The technical solution of the present invention is as follows: a heat insulation sleeve assembly for a magnetic lifting control rod drive mechanism includes a tube base, a guide sleeve, and a guide cover. The upper part of the tube base is a first end and the lower part is a second end. A first connecting end is provided at the lower part of the second end. The guide sleeve is fixedly connected to the first connecting end of the tube base. A fourth connecting end is provided at the upper part of the guide cover and a horn cover is provided at the lower part. The fourth connecting end of the guide cover is connected to the second fixed end of the guide sleeve.

[0007] The guide sleeve includes a first fixed end, and the interior of the first fixed end is provided with a plurality of limiting posts 2 along the upper and lower vertical directions, and a drainage groove is formed between the limiting posts 2.

[0008] The inner surface of the second limiting post is arc-shaped, and the radius of the arc is the same as the maximum radial dimension of the driving rod.

[0009] The guide sleeve and the tube seat are fixedly connected by threads.

[0010] The lower end of the tube seat has a radially penetrating guide groove, and the upper part of the guide sleeve is fitted with an anti-rotation ring. The guide sleeve and the anti-rotation ring are fixedly connected. The upper part of the anti-rotation ring is provided with a lug that is adapted to the guide groove. The guide groove and the lug are coupled.

[0011] The guide sleeve and the anti-rotation ring are fixedly connected by welding.

[0012] The second end of the tube seat is provided with a limiting post along the vertical direction from top to bottom.

[0013] The limiting posts are evenly distributed along the circumference.

[0014] The number of limiting posts one and limiting posts two are the same.

[0015] The tube seat, guide sleeve, and guide cover are made of the same metal material.

[0016] The radial dimension of the first end is larger than that of the second end.

[0017] The beneficial effects of this invention are as follows: Compared with the prior art, the heat shield assembly of this invention is in a fixed state, fundamentally solving the problem of wear and tear on the heat shield assembly. Currently, reactors are gradually developing towards smaller reactors, and the heat shield assembly structure of this invention is more compact and better suited to smaller reactors. While ensuring smooth rod drop, the radial support of the drive rod is strengthened, extending the service life of the device. Attached Figure Description

[0018] Figure 1 This is a perspective view of the heat insulation sleeve assembly of a magnetic lifting control rod drive mechanism provided by the present invention;

[0019] Figure 2This is a three-dimensional view of the tube seat;

[0020] Figure 3 A 3D diagram to prevent rotation;

[0021] Figure 4 This is a cross-sectional view of the internal structure of the heat insulation sleeve assembly of a magnetic lifting control rod drive mechanism provided by the present invention.

[0022] Figure 5 A three-dimensional view of the guide sleeve;

[0023] Figure 6 for Figure 5 A partial view at point A in the middle.

[0024] In the diagram: 1. Pipe seat, 2. Anti-rotation ring, 3. Guide sleeve, 4. Guide cover, 11. First end, 12. Second end, 13. Guide groove, 14. First connecting end, 15. Limiting post one, 21. Second connecting end, 22. Lug, 31. First fixed end, 32. Second fixed end, 33. Third connecting end, 34. Limiting post two, 35. Drainage groove, 41. Fourth connecting end, 42. Horn cover. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] To make the technical solution and advantages of the present invention clearer and easier to understand, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the terms "upper," "lower," "left," "right," "inner," "outer," "horizontal," and "vertical," etc., used in the following description to indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings. These terms are used only for the convenience of describing the present invention and do not specifically refer to the actual orientation or position of the device during implementation; that is, these terms should not be construed as limiting the present invention.

[0027] In the first embodiment of the present invention, as Figure 1-6 As shown, the present invention discloses a heat insulation sleeve assembly for a magnetic lifting control rod drive mechanism, comprising a tube base 1, a guide sleeve 3, and a guide cover 4. The tube base 1 has a first end 11 at its upper part and a second end 12 at its lower part. The first end 11 is fixedly connected to the sealing shell of the drive mechanism, and the radial dimension of the first end 11 is larger than that of the second end 12. A first connecting end 14 is provided at the lower part of the second end 12, and the guide sleeve 3 is fixedly connected to the first connecting end 14 of the tube base 1. The guide cover 4 has a fourth connecting end 41 at its upper part and a horn cover 42 at its lower part. The fourth connecting end 41 of the guide cover 4 is fixedly connected to the second fixed end 32 of the guide sleeve 3.

[0028] The magnetic lifting control rod drive mechanism has a drive rod installed inside the heat insulation sleeve assembly. The drive rod is slidably connected to the heat insulation sleeve assembly in the vertical direction and guides the sliding process of the drive rod.

[0029] In another embodiment, to improve the interchangeability of the thermal insulation sleeve assembly, the guide sleeve 3 and the pipe seat 1 are fixedly connected by threads. To prevent the guide sleeve 3 from falling off during use, a radially penetrating guide groove 13 is formed at the lower end of the pipe seat 1. An anti-rotation ring 2 is fitted onto the upper part of the guide sleeve 3, and the guide sleeve 3 and the anti-rotation ring 2 are fixedly connected. The upper part of the anti-rotation ring 2 is provided with a lug 22 that adapts to the guide groove 13, and the guide groove 13 and the lug 22 are coupled.

[0030] Furthermore, the guide sleeve 3 and the anti-rotation ring 2 are fixedly connected by welding.

[0031] In another embodiment, on the one hand, due to the presence of flow-induced vibration during operation, the drive rod will continuously vibrate radially. In this case, it is necessary to reduce the gap between the drive rod and the guide sleeve 3 to suppress its radial vibration. On the other hand, it is necessary to increase the gap between the drive rod and the guide sleeve 3 to reduce the resistance brought by the fluid when the drive rod drops.

[0032] In order for the heat insulation sleeve assembly to meet the above requirements, the first fixed end 31 of the guide sleeve 3 is provided with limiting posts 34 along the upper and lower vertical directions, and a drainage groove 35 is naturally formed between the limiting posts 34.

[0033] Preferably, the limiting posts 34 are evenly distributed along the circumference.

[0034] Preferably, the inner surface of the second limiting post 34 is arc-shaped, and its radius of curvature is the same as the maximum radial dimension of the drive rod. At this time, the contact between the drive rod and the second limiting post 34 changes from line contact to surface contact, which reduces the local stress of the second limiting post 34 and increases the service life of the guide sleeve 3.

[0035] Furthermore, the second end 12 of the tube seat 1 is provided with a limiting post 15 along the vertical direction from top to bottom.

[0036] Preferably, the limiting posts 15 are evenly distributed along the circumference.

[0037] The number of limiting posts 15 and limiting posts 34 are the same.

[0038] Preferably, in order to reduce electrochemical corrosion at the interface of different metal materials, the tube seat 1, guide sleeve 3, and guide cover 4 are made of the same metal material.

[0039] Finally, it should be noted that the above embodiments only illustrate several implementation methods of the present invention. For those skilled in the art, several combinations and improvements can be made without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A heat insulation sleeve assembly for a magnetic lifting control rod drive mechanism, characterized in that: It includes a tube seat (1), a guide sleeve (3), and a guide cover (4). The tube seat (1) has a first end (11) at the top and a second end (12) at the bottom. The second end (12) has a first connecting end (14) at the bottom. The guide sleeve (3) is fixedly connected to the first connecting end (14) of the tube seat (1). The guide cover (4) has a fourth connecting end (41) at the top and a horn cover (42) at the bottom. The fourth connecting end (41) of the guide cover (4) is connected to the second fixed end (32) of the guide sleeve (3). The guide sleeve (3) includes a first fixed end (31), and a plurality of limiting posts (34) are provided inside the first fixed end (31) along the upper and lower vertical directions, and a drainage groove (35) is formed between the limiting posts (34).

2. The heat insulation sleeve assembly of the magnetic lifting control rod drive mechanism according to claim 1, characterized in that: The inner surface of the limiting post 2 (34) is set as arc-shaped, and the radius of the arc is the same as the maximum radial dimension of the driving rod.

3. The heat insulation sleeve assembly of the magnetic lifting control rod drive mechanism according to claim 1, characterized in that: The guide sleeve (3) and the tube seat (1) are fixedly connected by threads.

4. The heat insulation sleeve assembly of the magnetic lifting type control rod drive mechanism according to claim 1, characterized in that: The lower end of the tube seat (1) has a radially penetrating guide groove (13), and the upper part of the guide sleeve (3) is fitted with an anti-rotation ring (2). The guide sleeve (3) and the anti-rotation ring (2) are fixedly connected. The upper part of the anti-rotation ring (2) is provided with a lug (22) that is adapted to the guide groove (13). The guide groove (13) and the lug (22) are coupled.

5. The heat insulation sleeve assembly of a magnetic lifting control rod drive mechanism according to claim 4, characterized in that: The guide sleeve (3) and the anti-rotation ring (2) are fixedly connected by welding.

6. The heat insulation sleeve assembly of a magnetic lifting control rod drive mechanism according to claim 4, characterized in that: The second end (12) of the tube seat (1) is provided with a limiting post (15) along the vertical direction of the upper and lower sides.

7. The heat insulation sleeve assembly of a magnetic lifting control rod drive mechanism according to claim 1, characterized in that: The limiting posts (34) are evenly distributed along the circumference.

8. The heat insulation sleeve assembly of a magnetic lifting control rod drive mechanism according to claim 6, characterized in that: The number of limiting posts one (15) and limiting posts two (34) are the same.

9. The heat insulation sleeve assembly of the magnetic lifting control rod drive mechanism according to claim 1, characterized in that: The tube seat (1), guide sleeve (3), and guide cover (4) are made of the same metal material.

10. The heat insulation sleeve assembly of the magnetic lifting control rod drive mechanism according to claim 1, characterized in that: The radial dimension of the first end (11) is greater than that of the second end (12).

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