Ball self-locking anti-loosening quick-release type heat casing pipe structure

Abstract

The invention belongs to the technical field of heat sleeves of control rod driving mechanisms, aims to solve the problem that a heat sleeve is mounted from the lower portion of a top cover, and discloses a ball self-locking anti-loosening quick-release heat sleeve structure which comprises a sleeve, an upper end, a connecting ring and a sleeve seat assembly, the upper end is arranged on the outer side of the sleeve, the connecting ring is arranged at a lower pipe opening of a CRDM (control rod driving mechanism) pipe seat, and the sleeve seat assembly is arranged on the upper end of the sleeve. The pipe seat assembly is installed outside the upper end and provided with a key, a self-locking sleeve, a ball, a spring seat, a spring and a pipe seat, the key is arranged on the inner side of the pipe seat, a ball hole is formed in the outer side of the pipe seat, the self-locking sleeve is arranged outside the pipe seat in a sleeving mode, a ball groove is formed in the inner side wall of the self-locking sleeve, and the self-locking sleeve, the ball hole and a ball self-locking groove of the connecting ring form a space for containing the ball. The self-locking sleeve is sleeved with the spring seat, and the spring is arranged on the inner side of the spring seat. The heat sleeve structure is installed from the lower portion of the top cover, and the operation that when a heat sleeve is replaced, an upper driving mechanism is detached, and the pressure-bearing boundary of a loop is damaged is avoided.

Description

Technical Field

[0001] The present application belongs to the technical field of control rod drive mechanism thermowells, and in particular relates to a ball self-locking, anti-loosening, quick-detachable thermowell structure. Background Art

[0002] The control rod drive mechanism (CRDM) thermowell is a component of the control rod drive mechanism (CRDM). It is installed in the CRDM socket on the pressure vessel head with a radial clearance fit and no axial restraint. It is a floating component within the reactor. The CRDM thermowell consists of three parts: an upper flange, a straight middle section, and a lower flared section. Made of stainless steel, it is normally suspended from the CRDM socket in a non-fixed, suspended installation. Because the thermowell is a non-fixed component, it is subject to slight vibrations caused by the impact of coolant flow within the reactor, which can lead to fretting wear or cracks.

[0003] like Figure 9 As shown, the old thermowell 11 is installed in the CRDM tube socket 1 on the pressure vessel top cover 7 and is suspended and supported by the top end. Since it is a floating component in the stack, under the impact and vibration of the fluid, the top end will contact and rub, causing the position of the old thermowell 11 to drop. When the drop distance exceeds the standard, the old thermowell 11 needs to be replaced.

[0004] If the CRDM thermowell has excessive defects and cannot be mitigated or repaired, it must be replaced. Replacing the thermowell involves removing the old thermowell and installing a new one. There are two common approaches to replacing a thermowell: replacing it from above the top cover and replacing it from below the top cover.

[0005] Replacing the thermowells of in-service units from above the top cover involves the following process steps: cutting the top CRDM assembly, cutting the lower sealing weld, shaping the groove, cutting the old thermowell, repairing the CRDM tube seat contour, designing and installing the new thermowell structure, welding the bell cover, welding the CRDM assembly, non-destructive testing of the welds, and hydrostatic testing of the unit. Although this technology is relatively mature, it is complex, involves multiple steps, a long construction period, and poor economic efficiency. Furthermore, for in-service units, due to factors such as high radiation doses and inaccessible personnel, a large amount of specialized equipment must be developed, and on-site implementation also requires a long maintenance window. Therefore, it is necessary to develop a process and technical route for replacing the thermowells from below the top cover. Summary of the Invention

[0006] The purpose of the present application is to provide a ball self-locking anti-loosening quick-release thermowell structure, which is a new type of thermowell structure installed from the bottom of the top cover, avoiding the operation of removing the upper drive mechanism and damaging the pressure-bearing boundary of the primary circuit when replacing the thermowell, and solving the problem of installing the thermowell from the bottom of the top cover.

[0007] To achieve the above object, the application provides the following technical scheme: A ball self-locking anti-loose quick-release hot-jacket pipe structure, comprising a jacket pipe, an upper end head, a connecting ring, and a pipe seat assembly, wherein the upper end head is arranged outside the jacket pipe, the connecting ring is arranged at the lower pipe opening of the CRDM pipe seat, and the pipe seat assembly is installed outside the upper end head; The pipe seat assembly has a key, a self-locking sleeve, a ball, a spring seat, a spring, and a pipe seat, wherein 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, the inner side wall of the self-locking sleeve is provided with a ball groove, and the ball groove, the ball hole, and the ball self-locking groove of the connecting ring form a space for accommodating the ball, the spring seat is sleeved outside the self-locking sleeve, and the spring is arranged inside the spring seat.

[0008] In some embodiments, a self-locking driving head is arranged below the self-locking sleeve and passes through the reverse Z-shaped groove of the spring seat.

[0009] In some embodiments, the self-locking driving head is a convex block structure, and the number of the self-locking driving heads is 2.

[0010] In some embodiments, the spring is arranged between the self-locking sleeve and the spring seat and presses the self-locking sleeve downward.

[0011] In some embodiments, the lower part of the pipe seat is an inner conical surface, and the inner conical surface is matched with the upper end head.

[0012] In some embodiments, the connecting ring has two key grooves, the number of the keys is 2, and the keys and the key grooves are arranged correspondingly.

[0013] In some embodiments, the key is matched with the key groove, enters from the opening of the key groove upward, is rotated counterclockwise after being in place, falls into the limiting groove of the key groove, the ball is aligned with the ball self-locking groove, the ball is inlaid in the ball hole, the outside of the ball is limited by the self-locking sleeve, when the self-locking sleeve is in the upper position, the ball groove is aligned with the ball, the ball is retracted into the ball groove, and at this time, the self-locking unlocking state is achieved.

[0014] In some embodiments, the shape of the key groove is a 7-shaped structure.

[0015] In some embodiments, the connecting ring is generally in a circular ring shape, a section of a stopper is arranged at the lower end of the connecting ring, and the connecting ring is fixed to the CRDM pipe seat by screwing.

[0016] In some embodiments, a horn cover is arranged below the jacket pipe.

[0017] Compared with the prior art, the ball self-locking anti-loose quick disassembly type hot sleeve pipe structure provided by the application has the following beneficial effects: The application is used for replacing the defective sleeve pipe when the sleeve pipe of the CRDM is seriously worn and reaches the replacement standard. The application adopts the replacement mode from the bottom of the top cover, avoids cutting and removing the control rod drive mechanism, reduces the workload, and improves the economy of the nuclear power plant overhaul.

[0018] Further, the application changes the installation support position of the original sleeve pipe, moves the sleeve pipe support position downward to the lower pipe opening of the CRDM pipe seat under the premise of ensuring that the original design function is unchanged and the sleeve pipe structure strength is not reduced, adopts the ball self-locking anti-loose quick disassembly type structure between the new pipe seat and the connecting piece, can realize the repeated disassembly of the hot sleeve pipe structure, and the application is a permanent solution to the hot sleeve pipe defects of the M310 and Hualong No. 1 reactor types. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the application, the following will briefly introduce the drawings needed to be used in the technical description.

[0020] Figure 1 The installation structure diagram of the ball self-locking anti-loose quick disassembly type hot sleeve pipe structure provided by the application; Figure 2 The installation sectional view of the ball self-locking anti-loose quick disassembly type hot sleeve pipe structure provided by the application; Figure 3 The connecting ring installation diagram provided by the application; Figure 4 The self-locking open state diagram provided by the application; Figure 5 The self-locking open sectional view provided by the application; Figure 6 The self-locking closed state diagram provided by the application; Figure 7 The self-locking closed sectional view provided by the application; Figure 8 The sectional detail view of the ball self-locking anti-loose quick disassembly type hot sleeve pipe structure provided by the application; Figure 9 The old hot sleeve pipe installation diagram provided by the prior art.

[0021] Explanation of reference signs: 1, CRDM pipe seat; 2, sleeve pipe; 3, horn cover; 4, upper end; 5, connecting ring; 6, pipe seat assembly; 7, top cover; 8, biological shielding wall; 11, old hot sleeve pipe; 51, key groove; 52, ball self-locking groove; 61; key; 62; self-locking sleeve; 63; ball; 64; spring seat; 65; spring; 66; new pipe seat; 621; Self-locking drive head; 622; Ball groove. DETAILED DESCRIPTION

[0022] The following is further explained in detail through specific implementation methods.

[0023] The present application provides a ball self-locking anti-loosening quick-detachable thermal sleeve structure. Compared with the old thermal sleeve 11, the upper end 4 of the present application is moved down to the bottom of the CRDM tube seat 1, so that the new thermal sleeve can be inserted into the middle hole of the CRDM tube seat 1. Figures 1 to 8 As shown, the thermal sleeve structure includes a sleeve 2, an upper end 4, a horn cover 3, a connecting ring 5, and a tube base assembly 6.

[0024] The upper end cap 4 is mounted on the sleeve 2, the bell housing 3 is positioned below the sleeve 2, and the connecting ring 5 is positioned at the lower end of the CRDM tube base 1 and secured to the CRDM tube base 1 via threads. The tube base assembly 6 is mounted externally to the upper end cap 4. The inner conical surface of the tube base assembly 6 contacts the upper end cap 4 to provide support for the entire sleeve 2. The tube base assembly 6 is also mounted externally on the connecting ring 5, using a keyway 51 for mounting and a ball-type self-locking groove 52 for locking and preventing loosening.

[0025] The sleeve 2 is inserted into the CRDM pipe seat 1 for setting. The height of the upper end 4 on the sleeve 2 is related to the position of the thermowell. The closer to the middle position of the pressure vessel top cover 7, the higher the upper end 4 of the new thermowell is, and the closer to the edge position, the lower the upper end 4 is.

[0026] In order to insert the sleeve 2 into the CRDM pipe seat 1 and provide support, the present application installs a connecting ring 5 at the lower end of the CRDM pipe seat 1. The connecting ring 5 is fixed to the lower end of the CRDM pipe seat 1 by screwing bolts. The overall shape of the connecting ring is annular, with a stop at the lower end and two key slots 51 evenly distributed around the circumference. The shape of the key slots 51 is "7" (as shown in Figure 1). Figure 3 As shown), it cooperates with the key 61 of the tube base assembly 6 during installation.

[0027] The connecting ring 5 also has two ball self-locking grooves 52 evenly distributed around the circumference, which cooperate with the balls 63 of the pipe seat assembly 6 to achieve the effect of self-locking and anti-rotation fixation. The ball self-locking grooves 52 are spherical grooves, not through grooves.

[0028] The pipe base assembly 6 comprises a key 61, a self-locking sleeve 62, a ball 63, a spring seat 64, a spring 65, and a pipe base 66. The inner side wall of the pipe base 66 is provided with the key 61, and the outer side wall is provided with a ball hole which is inwardly tapered, and the ball 63 cannot fall off from the inner side wall of the pipe base 66. The self-locking sleeve 62 is sleeved on the outside of the pipe base 66, and the inner side wall of the self-locking sleeve 62 is provided with an annular ball groove 622, and the ball self-locking groove 52, the ball groove 622 and the annular groove jointly form a space for accommodating the ball 63. The spring seat 64 is sleeved on the outside of the self-locking sleeve 62, and the spring 65 is arranged on the inner side of the spring seat 64 and is in a compressed state and presses on the self-locking sleeve 62.

[0029] The pipe base 66 is a newly designed, and the inner tapered surface below the pipe base 66 is in contact with the upper end head 4, and at the same time, the tapered surface provides the self-centering function for the upper end head 4. The two keys 61 are evenly welded and fixed on the inner wall of the pipe base 66. When the pipe base assembly 6 is installed, the key 61 is matched with the key groove 51, enters from the opening of the key groove 51, rotates counterclockwise after being in place, and falls into the limiting groove after being in place. At this time, the ball 63 is aligned with the ball self-locking groove 52. The ball 63 is embedded in the ball hole of the side wall of the pipe base 66, and since the ball hole has a tapered opening, the ball 63 cannot roll out from the inside. The outer side of the ball 63 is limited by the self-locking sleeve 62, and the self-locking sleeve 62 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 retreat into the ball groove 622. At this time, it is in the self-locking unlocking state, and the pipe base 66 can be removed.

[0030] The spring seat 64 is welded and connected with the pipe base 66, and the welding position is located at the lower end of the spring seat 64. It is welded after being assembled, and at the same time, there are two evenly distributed reverse “Z” grooves on it, which provide two operating positions for the self-locking driving head 621 of the self-locking sleeve 62.

[0031] The lower part of the self-locking sleeve 62 is provided with the self-locking driving head 621, which is a block structure protruding outward, and the number is two. The self-locking driving head 621 can pass through the reverse “Z” groove of the spring seat 64 (as shown in Figure 6 The self-locking driving head 621 can be rotated and lifted in the reverse “Z” groove under the action of external manual driving force, and the right upper position and the left lower position in the reverse “Z” groove are respectively in the unlocking and self-locking states. The unlocking and self-locking operations are realized by rotating and lifting the self-locking driving head 621.

[0032] The self-locking sleeve 62 is located between the tube seat 66 and the spring seat 64, and the self-locking driving head 621 thereof can move up and down and rotate slightly along the reverse "Z" groove of the spring seat 64. When the self-locking driving head 621 is in the upper position, the ball 63 can be removed, and the connecting ring 5 and the tube seat 66 lose the constraint of the ball 63 and can move relatively, which is the unlocked state; when the self-locking driving 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, and the connecting ring 5 and the tube seat 66 exist the constraint of the ball 63 and cannot move relatively, which is the self-locking state.

[0033] The spring 65 is located between the self-locking sleeve 62 and the spring seat 64, and presses the self-locking sleeve 62 downward to reduce the up-and-down vibration thereof.

[0034] The present hot sleeve pipe structure changes the support position of the sleeve pipe, i.e., the installation position of the upper end head, lowers the upper end head to the position of the lower pipe opening of the CRDM tube seat, facilitates installation, can maintain the original design function of the hot sleeve pipe, and does not reduce the strength of the sleeve pipe.

[0035] The present hot sleeve pipe structure adopts the method of adding a new tube seat and lowering the upper end head of the hot sleeve pipe, realizes the technical effect that the CRDM hot sleeve pipe is installed from below the top cover, and avoids damaging the primary loop pressure boundary when replacing the hot sleeve pipe from above the top cover.

[0036] The present hot sleeve pipe structure adopts the method of installing the connecting ring of the new hot sleeve pipe at the lower end of the CRDM tube seat, provides convenience for on-site construction, provides an interface for the installation of the new tube seat, is a key link for the application of the new hot sleeve pipe, and realizes the technical effect of convenience and reliability.

[0037] The present hot sleeve pipe structure adopts the ball self-locking anti-loose quick-release type new sleeve pipe structure, has the function of being detachable, can replace the defective sleeve pipe in the case that the settlement of the CRDM hot sleeve pipe is seriously out of standard and unacceptable, and can be used for M310 and Hualong No. 1 units to realize the purpose of replacing the CRDM hot sleeve pipe when the settlement thereof is out of standard.

[0038] The above merely describes specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which shall be covered within the protection scope of the present application.

Claims

1. A ball self-locking anti-loosening quick-release thermal sleeve structure, characterized in that: It comprises a sleeve (2), an upper end head (4), a connecting ring (5), and a pipe base assembly (6), wherein the upper end head (4) is arranged outside the sleeve (2), the connecting ring (5) is arranged at the lower pipe opening of the CRDM pipe base (1), and the pipe base assembly (6) is installed outside the upper end head (4); The tube seat assembly (6) comprises 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 arranged on the inner side of the tube seat (66). A ball hole is provided on the outer side of the tube seat (66). The self-locking sleeve (62) is sleeved on the outside of the tube seat (66). A ball groove (622) is provided on the inner side wall of the self-locking sleeve (62) and forms a space for accommodating the ball (63) together with the ball hole and the ball self-locking groove (52) of the connecting ring (5). The spring seat (64) is sleeved on the outside of the self-locking sleeve (62), and the spring (65) is arranged on the inner side of the spring seat (64).

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

3. The ball self-locking anti-loosening quick-release thermal sleeve structure according to claim 2, characterized in that: The self-locking drive heads (621) are an outwardly convex block-shaped structure, and there are two of them.

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

5. The ball self-locking anti-loosening quick-release thermal sleeve structure according to claim 1, characterized in that: The lower portion of the tube seat (66) is an inner conical surface, and the inner conical surface is adapted to fit the upper end head (4).

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

7. The ball self-locking anti-loosening quick-release thermal sleeve structure according to claim 6, characterized in that: The key (61) cooperates with the key slot (51), enters upward from the opening of the key slot (51), rotates counterclockwise after being in position, and falls into the limiting groove of the key slot (51). The ball (63) is aligned with the position of the ball self-locking groove (52), and the ball (63) is embedded in the ball hole. 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) is aligned with the ball (63), and the ball (63) retreats into the ball groove (622), and is now in a self-locking and unlocking state.

8. The ball self-locking anti-loosening quick-release thermal sleeve structure according to claim 6, characterized in that: The keyway (51) is in the shape of a 7.

9. The ball self-locking anti-loosening quick-release thermal sleeve structure according to claim 1, characterized in that: The connecting ring (5) is generally in the shape of a circular ring, and a stop is provided at the lower end. The connecting ring (5) is fixed to the CRDM tube seat (1) by screwing bolts.

10. The ball self-locking anti-loosening quick-release thermal sleeve structure according to claim 1, characterized in that: A horn cover (3) is provided below the sleeve (2).

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