Ball self-locking anti-loose quick-release hot-jacket pipe structure

Abstract

The application belongs to the technical field of control rod drive mechanism thermal sleeve pipe and aims to solve the problem of installing the thermal sleeve pipe from below the top cover, discloses a ball self-locking anti-loose quick disassembly type thermal sleeve pipe structure, which comprises a sleeve pipe, an upper end head, a connecting ring and a pipe seat assembly, the upper end head is arranged outside the sleeve pipe, the connecting ring is arranged at the lower pipe opening of the CRDM pipe seat, the pipe seat assembly is installed outside the upper end head, the pipe seat assembly is provided with a key, a self-locking sleeve, a ball, a spring seat, a spring and a pipe seat, the key is arranged inside the pipe seat, the outside of the pipe seat is provided with a ball hole, the self-locking sleeve is sleeved outside the pipe seat, a ball groove is arranged on the inner side wall of the self-locking sleeve and forms a space containing the ball with the ball hole and the ball self-locking groove of the connecting ring, the spring seat is sleeved outside the self-locking sleeve, and the spring is arranged inside the spring seat. The application is a novel thermal sleeve pipe structure installed from below the top cover, which avoids the operation of removing the upper drive mechanism to damage the pressure boundary of the primary loop during the replacement of the thermal sleeve pipe.

Description

Technical Field

[0001] This application belongs to the field of thermal sleeve technology for control rod drive mechanism, and particularly relates to a ball self-locking anti-loosening quick-release thermal sleeve structure. Background Technology

[0002] The control rod drive mechanism heat jacket is a component of the control rod drive mechanism (CRDM). It is installed in a CRDM socket on the pressure vessel top cover, with a radial clearance fit and no axial restraint, and is a floating component within the reactor. The CRDM heat jacket consists of three parts: an upper flange, a middle straight pipe section, and a lower flared end, all made of stainless steel. Normally, it is suspended from the CRDM socket using a non-fixed, suspended installation structure. Because the heat jacket is a non-fixed component, it experiences slight vibrations under the impact of coolant flow within the reactor, leading to fretting wear or cracking.

[0003] like Figure 9 As shown, the old heat jacket 11 is installed in the CRDM pipe seat 1 on the top cover 7 of the pressure vessel and is suspended and supported by the top end. As it is a floating component in the stack, the top end will contact and rub under the action of fluid impact and vibration, which will cause the position of the old heat jacket 11 to drop. If the drop distance exceeds the standard, the old heat jacket 11 needs to be replaced.

[0004] If the defects of the CRDM heat jacket exceed the standard and cannot be mitigated or repaired, replacement is required. Replacing the heat jacket involves removing the old heat jacket and installing the new one. There are generally two process routes for replacing the heat jacket: replacing it from above the top cover and replacing it from below the top cover.

[0005] The process of replacing the heat jacket from above the top cover of in-service units involves the following steps: cutting the CRDM assembly on the top of the reactor, cutting the lower sealing weld, beveling, cutting the old heat jacket, repairing the CRDM tube seat outline, designing and installing the new heat jacket structure, welding the horn cover, welding the CRDM assembly, non-destructive testing of the weld, and individual hydrostatic testing. Although this technology is relatively mature, it is complex, involves many procedures, has a long construction period, and is not economically viable. Furthermore, for in-service units, due to high dosage and inaccessibility to personnel, a large amount of specialized equipment needs to be developed, and on-site implementation requires a long maintenance window. Therefore, it is necessary to develop a process technology route for replacing the heat jacket from below the top cover. Summary of the Invention

[0006] The purpose of this application is to provide a ball-loaded self-locking anti-loosening quick-release heat sleeve structure. This structure is a novel heat sleeve structure that is installed from below the top cover, avoiding the operation of removing the upper drive mechanism and destroying the primary circuit pressure boundary when replacing the heat sleeve, and solving the problem of installing the heat sleeve from below the top cover.

[0007] To achieve the above objectives, this application provides the following technical solution:

[0008] A ball-bearing self-locking anti-loosening quick-release thermal sleeve structure includes a sleeve, an upper end, a connecting ring, and a tube seat assembly. The upper end is disposed on the outside of the sleeve, the connecting ring is disposed at the lower opening of the CRDM tube seat, and the tube seat assembly is installed on the outside of the upper end.

[0009] The tube seat assembly includes a key, a self-locking sleeve, a ball, a spring seat, a spring, and a tube seat. The key is located inside the tube seat, and the outer side of the tube seat has a ball hole. The self-locking sleeve is fitted onto the outside of the tube seat. The inner sidewall of the self-locking sleeve has a ball groove, which, together with the ball hole and the ball self-locking groove of the connecting ring, forms a space to accommodate the ball. The spring seat is fitted onto the outside of the self-locking sleeve, and the spring is located inside the spring seat.

[0010] In some embodiments, a self-locking drive head is provided below the self-locking sleeve, and the self-locking drive head is disposed through the reverse Z-groove of the spring seat.

[0011] In some embodiments, the self-locking drive head is a convex block structure, and the number of such heads is two.

[0012] In some embodiments, the spring is disposed between the self-locking sleeve and the spring seat, pressing the self-locking sleeve downward.

[0013] In some embodiments, the lower part of the tube seat is an inner conical surface, which is adapted to the upper end.

[0014] In some embodiments, the connecting ring has two keyways, and the number of keys is two, with the keys and keyways being configured correspondingly.

[0015] In some embodiments, the key engages with the keyway, enters upward from the opening of the keyway, rotates counterclockwise after reaching its position, and falls into the limiting groove of the keyway. The ball is aligned with the self-locking groove of the ball bearing, and the ball is embedded in the ball hole. The outer side of the ball is limited by the self-locking sleeve. When the self-locking sleeve is in the upper position, the ball groove aligns with the ball, and the ball retracts into the ball groove, at which point it is in a self-locking and unlocking state.

[0016] In some embodiments, the keyway is shaped like the number 7.

[0017] In some embodiments, the connecting ring is generally circular in shape, with a stop at the lower end, and the connecting ring is fixed to the CRDM pipe seat by means of bolt tightening.

[0018] In some embodiments, a horn cover is provided below the sleeve.

[0019] Compared with the prior art, the ball-loaded self-locking anti-loosening quick-release heat sleeve structure provided in this application has the following advantages:

[0020] This application is used for replacing defective CRDM bushings when they are severely worn and meet replacement criteria. This application employs a replacement method from below the top cover, avoiding the need to cut and remove the control rod drive mechanism, reducing workload, and improving the economics of nuclear power plant overhauls.

[0021] Furthermore, this application changes the original installation support position of the sleeve. Under the premise of ensuring that the original design function remains unchanged and the strength of the sleeve structure is not reduced, the sleeve support position is moved down to the lower pipe opening of the CRDM pipe seat. The new pipe seat and the connector adopt a ball self-locking anti-loosening quick-release structure, which can realize repeated disassembly and assembly of this thermal sleeve structure. This application is a permanent solution to the defects of the thermal sleeve of M310 and Hualong One reactor. Attached Figure Description

[0022] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the technical description will be briefly introduced below.

[0023] Figure 1 This is an installation structure diagram of the ball-load self-locking anti-loosening quick-release heat sleeve structure provided in this application;

[0024] Figure 2 This is an installation cross-sectional view of the ball-load self-locking anti-loosening quick-release heat sleeve structure provided in this application;

[0025] Figure 3 The connecting ring installation diagram provided in this application;

[0026] Figure 4 The self-locking open state diagram provided in this application;

[0027] Figure 5 A cross-sectional view of the self-locking mechanism provided in this application;

[0028] Figure 6 The self-locking closure state diagram provided in this application;

[0029] Figure 7 A self-locking closure cross-sectional view provided for this application;

[0030] Figure 8 A detailed cross-sectional view of the ball-loaded self-locking anti-loosening quick-release heat sleeve structure provided in this application;

[0031] Figure 9 The old heat jacket installation diagram provided by existing technology.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. CRDM tube socket; 2. Sleeve; 3. Horn cover; 4. Upper end; 5. Connecting ring; 6. Tube socket assembly; 7. Top cover; 8. Bio-shielding wall;

[0034] 11; Used heat jacket;

[0035] 51; Keyway; 52; Ball self-locking groove;

[0036] 61; Key; 62; Self-locking sleeve; 63; Ball; 64; Spring seat; 65; Spring; 66; New tube seat;

[0037] 621; self-locking drive head; 622; ball groove. Detailed Implementation

[0038] The following detailed description provides further details on specific implementation methods.

[0039] This application provides a ball-bearing self-locking anti-loosening quick-release heat sleeve structure. Compared with the old heat sleeve 11, the upper end 4 of this application is moved downwards, to below the CRDM tube seat 1, so that the new heat sleeve can be inserted into the central hole of the CRDM tube seat 1. Figures 1 to 8 As shown, this heat jacket structure includes a jacket 2, an upper end 4, a flared cover 3, a connecting ring 5, and a pipe seat assembly 6.

[0040] The upper end 4 is mounted on the sleeve 2, the horn cover 3 is positioned below the sleeve 2, and the connecting ring 5 is positioned at the lower end of the CRDM pipe seat 1 and is fixed to the CRDM pipe seat 1 by threads. A pipe seat assembly 6 is mounted externally to the upper end 4, and the inner conical surface of the pipe seat assembly 6 contacts the upper end 4 to provide support for the entire sleeve 2. Simultaneously, the pipe seat assembly 6 is hooked onto the outside of the connecting ring 5 using a keyway 51 and a ball-loaded self-locking groove 52 for locking and preventing loosening.

[0041] The sleeve 2 is inserted into the CRDM pipe socket 1. The height of the upper end 4 on the sleeve 2 is related to the position of the heat sleeve. The higher the upper end 4 of the new heat sleeve is, the closer it is to the middle of the pressure vessel top cover 7. The lower the upper end 4 is, the closer it is to the edge.

[0042] To allow the sleeve 2 to be inserted into the CRDM pipe socket 1 and to provide support, this application installs a connecting ring 5 at the lower end of the CRDM pipe socket 1. The connecting ring 5 is fixed to the lower end of the CRDM pipe socket 1 by bolt tightening. It is generally annular in shape, with a stop at the lower end, and two keyways 51 evenly distributed circumferentially. The keyways 51 are shaped like the number "7" (e.g., ...). Figure 3 As shown), it is installed in conjunction with key 61 of the pipe socket assembly 6.

[0043] The connecting ring 5 also has two ball self-locking grooves 52 evenly distributed around its circumference, which cooperate with the ball 63 of the tube seat assembly 6 to play a self-locking and anti-rotation fixing role. The ball self-locking grooves 52 are spherical grooves, not through grooves.

[0044] The tube seat assembly 6 includes a key 61, a self-locking sleeve 62, a ball 63, a spring seat 64, a spring 65, and a tube seat 66. The inner wall of the tube seat 66 has a key 61, and the outer wall has a ball hole that tapers inwards, preventing the ball 63 from falling off the inner wall of the tube seat 66. The self-locking sleeve 62 is fitted onto the outside of the tube seat 66. The inner wall of the self-locking sleeve 62 has an annular ball groove 622. The ball self-locking groove 52, the ball groove 622, and the annular groove together form a space to accommodate the ball 63. The spring seat 64 is fitted onto the outside of the self-locking sleeve 62, and the spring 65 is located inside the spring seat 64, compressed and pressing against the self-locking sleeve 62.

[0045] The tube seat 66 is a completely new design. The inner conical surface at the bottom of the tube seat 66 contacts and mates with the upper end head 4, while the conical surface also provides a self-centering function for the upper end head 4. Two keys 61 are evenly welded and fixed to the inner wall of the tube seat 66. During the installation of the tube seat assembly 6, the keys 61 mate with the keyway 51, advancing upwards from the opening of the keyway 51. After reaching the desired position, they rotate counterclockwise until they fall into the limiting groove. At this time, the ball 63 is aligned with the ball self-locking groove 52. The ball 63 is embedded in the ball hole on the side wall of the tube seat 66. Because the ball hole has a constriction, the ball 63 will not roll out from the inside. The outer side of the ball 63 is limited by the self-locking sleeve 62, which has a ball groove 622. When the self-locking sleeve 62 is in the upper position, the ball groove 622 is aligned with the ball 63, and the ball 63 can retract into the ball groove 622. At this time, it is in the self-locking and unlocking state, and the tube seat 66 can be removed.

[0046] The spring seat 64 is welded to the tube seat 66. The welding position is located at the lower end of the spring seat 64. The welding is done after assembly. At the same time, there are two evenly distributed reverse "Z" grooves on it, which provide two operating positions, upper and lower, for the self-locking drive head 621 of the self-locking sleeve 62.

[0047] Below the self-locking sleeve 62 is a self-locking drive head 621. The self-locking drive head 621 is a convex block structure, and there are two of them. The self-locking drive head 621 can pass through the reverse "Z" groove arrangement of the spring seat 64 (e.g., Figure 6 As shown, the self-locking drive head 621 can rotate and lift within the reverse "Z" groove under external manual driving force. The upper right and lower left positions within the reverse "Z" groove represent the unlocked and self-locked states, respectively. Unlocking and self-locking operations are achieved by rotating and lifting the self-locking drive head 621.

[0048] The self-locking sleeve 62 is located between the tube seat 66 and the spring seat 64. Its self-locking drive head 621 can move up and down and rotate within a small range along the reverse "Z" groove of the spring seat 64. When the self-locking drive head 621 is in the upper position, the ball 63 can be disengaged, and the connecting ring 5 and the tube seat 66 lose the constraint of the ball 63 and can move relative to each other, which is the unlocked state. When the self-locking drive head 621 is in the lower position, the ball 63 is pushed out by the side wall of the self-locking sleeve 62 and filled into the ball self-locking groove 52. The connecting ring 5 and the tube seat 66 are constrained by the ball 63 and cannot move relative to each other, which is the self-locking state.

[0049] Spring 65 is located between self-locking sleeve 62 and spring seat 64, pressing down on self-locking sleeve 62 to reduce its vertical vibration.

[0050] This heat jacket structure changes the support part of the jacket, namely the installation position of the upper end, lowering the upper end to the position of the lower pipe opening of the CRDM pipe seat, which facilitates installation, maintains the original design function of the heat jacket, and does not reduce the strength of the jacket.

[0051] This heat jacket structure adopts the method of adding a new pipe seat and moving the upper end of the heat jacket downward, which realizes the technical effect of installing the CRDM heat jacket from below the top cover, and avoids the disruption of the primary circuit pressure boundary when replacing the heat jacket from above the top cover.

[0052] This heat jacket structure uses a method of installing the new heat jacket connecting ring at the lower end of the CRDM pipe seat, which facilitates on-site construction and provides an interface for the installation of the new pipe seat. It is a key link in the application of the new heat jacket and achieves convenient and reliable technical results.

[0053] This heat jacket structure adopts a new type of ball-bearing self-locking anti-loosening quick-release jacket structure, which has a detachable function and can replace defective jackets when the settlement of CRDM heat jackets is seriously excessive and unacceptable. This heat jacket structure can be used in M310 and Hualong One units to achieve the purpose of replacing CRDM heat jackets when settlement exceeds the standard.

[0054] The above description is only a specific embodiment of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application.

Claims

1. A ball-bearing self-locking anti-loosening quick-release thermal sleeve structure, characterized in that, It includes a sleeve (2), an upper end (4), a connecting ring (5), and a pipe seat assembly (6). The upper end (4) is located outside the sleeve (2), the connecting ring (5) is located at the lower pipe opening of the CRDM pipe seat (1), and the pipe seat assembly (6) is installed outside the upper end (4). The tube seat assembly (6) has a key (61), a self-locking sleeve (62), a ball (63), a spring seat (64), a spring (65), and a tube seat (66). The key (61) is located inside the tube seat (66), and the outer side of the tube seat (66) has a ball hole. The self-locking sleeve (62) is fitted outside the tube seat (66). The inner sidewall of the self-locking sleeve (62) has a ball groove (622) which, together with the ball hole and the ball self-locking groove (52) of the connecting ring (5), forms a space to accommodate the ball (63). The spring seat (64) is fitted outside the self-locking sleeve (62), and the spring (65) is located inside the spring seat (64).

2. The ball-loaded self-locking anti-loosening quick-release heat sleeve structure according to claim 1, characterized in that, The self-locking sleeve (62) is provided with a self-locking drive head (621) below it, and the self-locking drive head (621) passes through the reverse Z-groove of the spring seat (64).

3. The ball-loaded self-locking anti-loosening quick-release heat sleeve structure according to claim 2, characterized in that, The self-locking drive head (621) is a convex block structure, and there are 2 of them.

4. The ball-loaded self-locking anti-loosening quick-release heat sleeve structure according to claim 1, characterized in that, The spring (65) is located between the self-locking sleeve (62) and the spring seat (64), pressing the self-locking sleeve (62) downward.

5. The ball-loaded self-locking anti-loosening quick-release heat sleeve structure according to claim 1, characterized in that, The lower part of the tube seat (66) is an inner conical surface, which is adapted to the upper end (4).

6. The ball-loaded self-locking anti-loosening quick-release heat sleeve structure according to claim 1, characterized in that, The connecting ring (5) has two keyways (51), and the number of keys (61) is 2. The keys (61) and the keyways (51) are set accordingly.

7. The ball-loaded self-locking anti-loosening quick-release heat sleeve structure according to claim 6, characterized in that, The key (61) engages with the keyway (51), enters upward from the opening of the keyway (51), rotates counterclockwise after reaching its position, and falls into the limiting groove of the keyway (51). The ball (63) is aligned with the ball self-locking groove (52), the ball (63) is embedded in the ball hole, and the outer side of the ball (63) is limited by the self-locking sleeve (62). When the self-locking sleeve (62) is in the upper position, the ball groove (622) aligns with the ball (63), and the ball (63) retracts into the ball groove (622), at which time it is in the self-locking and unlocking state.

8. The ball-loaded self-locking anti-loosening quick-release heat sleeve structure according to claim 6, characterized in that, The keyway (51) is shaped like the number 7.

9. The ball-loaded self-locking anti-loosening quick-release heat sleeve structure according to claim 1, characterized in that, The connecting ring (5) is generally circular in shape, with a stop at the lower end. The connecting ring (5) is fixed to the CRDM pipe seat (1) by bolt screwing.

10. The ball-loaded self-locking anti-loosening quick-release heat sleeve structure according to claim 1, characterized in that, The sleeve (2) is provided with a horn cover (3) below it.

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