A reactor drive rod reinstallation wrench

Abstract

The present invention belongs to the technical field of reactor maintenance, and particularly relates to a reactor drive rod reinstallation wrench. It includes an inner wrench and an outer wrench. The outer wrench is sleeved on the inner wrench and is used to connect and loosen the inner wrench with the drive rod. The inner wrench includes an inner wrench sleeve. The upper part of the connecting column is connected to the bottom of the inner wrench sleeve in the form of socket welding, and the lower part is connected to a cross universal joint. The lower part of the cross universal joint is connected with a connecting rod. An external thread section is provided on the connecting rod, and a locking nut is engaged with the external thread section and installed on the connecting rod. It can move up and down on the connecting rod through thread rotation. A pin shaft is installed in the through hole at the lower end of the connecting rod and cooperates with the "J"-type keyway at the head of the drive rod for connecting the wrench with the drive rod. The outer wrench includes an outer wrench sleeve, an outer wrench handle, and a sector key. The present invention improves the efficiency of the drive rod reinstallation work and avoids industrial safety and human error incidents during the operation process.

Description

Technical Field

[0001] The present invention belongs to the technical field of reactor maintenance, and particularly relates to a reactor drive rod reinstallation wrench. Background Art

[0002] The ШЭМ-3 type control rod drive mechanism is used for the up and down movement of the control rod and fixing it at the uppermost, lowermost or intermediate position. The position information of the control rod can be known through the position indicator. The control rod is inserted into or withdrawn from the reactor core through the control rod drive mechanism to achieve power startup, power control, and reactor shutdown. In the event of an emergency reactor shutdown, the drive mechanism is powered off and the control rod drops to the bottom. The control rod drive mechanism consists of five major parts: an electromagnet assembly, a pressure-resistant shell, a moving assembly, a drive rod, and a position indicator. The drive rod, as an important part of the control rod drive mechanism, is installed in the moving assembly. Its lower part is reliably connected to the control rod assembly through a locking pin and a fixing block. The upper part is a toothed cylindrical sleeve, and the overall up and down movement of the drive rod and the control rod assembly is achieved under the drive of the movable parts and pawls of the moving assembly. The full length of the drive rod is 6050 mm and the weight is 16.7 kg. The structure is as Figure 1 shown.

[0003] During the annual refueling overhaul of the unit, in order not to affect the lifting of the upper reactor components, 103 drive rods need to be uncoupled from the control rod assembly and lifted from the installation position to the transportation position (the head of the drive rod is 1245 mm higher than the head of the moving assembly) before the upper components are removed, and the drive rods are supported at the head of the moving assembly using special fixtures. After the upper components are reinstalled and sealed, these 103 drive rods need to be reinstalled from the transportation position to the installation position, and further the interlocking work between the drive rod and the control rod assembly is carried out. The drive rod reinstallation work is carried out in two steps. First, the staff manually lowers the drive rod from 1245 mm higher than the head of the moving assembly to 300 mm higher than the head of the moving assembly, and then connects the drive rod wrench to the head of the drive rod and manually lowers it to the transportation position. The lowering length of the drive rod using the wrench is about 4.8 m, and most of the length is inside the moving assembly, there is an inherent hidden danger that it is impossible to confirm visually throughout the process whether the connection between the head of the drive rod and the wrench is reliable. The drive rod reinstallation work needs to be repeated 103 times, and affected by the on-site high-temperature working environment and high radiation environment dose rate, the probability of human error is relatively high. The currently used drive rod wrench (such as Figure 2) It has a double-layer sleeve structure inside and outside. There are two symmetrical pin keys at the lower end of the inner sleeve, which cooperate with the "J"-shaped keyway at the head of the drive rod to realize the connection between the drive rod wrench and the drive rod. When reinstalling the drive rod, one worker holds the outer wrench of the drive rod wrench with both hands and vertically lifts the drive rod wrench. Another worker aligns the pin key at the lower end of the inner wrench with the "J"-shaped keyway at the head of the drive rod, inserts it downward, rotates it clockwise to the end and then lifts it up to complete the connection between the wrench and the drive rod. Then, the two workers cooperate to slowly lower the drive rod to the installation position while holding the outer wrench of the drive rod wrench. Finally, rotate the inner wrench counterclockwise to the end and then lift it up to remove the drive rod wrench.

[0004] Based on years of use experience and relevant experience feedback events, the following problems or potential hazards are found in the use of the drive rod wrench during the drive rod reinstallation work: 1. Only the inner wrench realizes the connection function between the drive rod wrench and the drive rod when using the wrench, and the outer wrench has no actual function; 2. The drive rod wrench is very long and the whole length is a rigid structure. Therefore, when connecting the wrench to the head of the drive rod, the coaxiality requirement for the wrench and the drive rod is relatively high. During the work, the worker holding the wrench often needs to communicate with the worker responsible for connection many times and adjust the perpendicularity of the wrench to complete the connection between the wrench and the drive rod, which not only prolongs the working time but also increases the radiation exposure dose of the workers; 3. After performing the same work many times and affected by the high-temperature working environment and high radiation environment dose rate on site, there have been many incidents where the drive rod wrench cannot be rotated to the end, the wrench and the drive rod are disconnected during the shaking process of lowering the drive rod, and the drive rod falls and is damaged. The lack of anti-drop design for the drive rod wrench is a contributing factor to the above incidents, resulting in unnecessary equipment damage and economic losses.

[0005] To solve the problems and potential safety hazards existing in the use of the existing drive rod wrench, improve the efficiency of the drive rod reinstallation work, reduce the radiation exposure dose of the workers, and at the same time avoid unnecessary equipment damage and economic loss incidents, the present invention provides a special wrench for reinstalling the reactor drive rod. Summary of the Invention

[0006] The purpose of the present invention is to provide a wrench for reinstalling the reactor drive rod, which solves the problems and potential safety hazards existing in the use of the existing drive rod wrench, improves the efficiency of the drive rod reinstallation work, reduces the radiation exposure dose of the workers, and avoids industrial safety and human error incidents during the operation.

[0007] The technical solution adopted by the present invention:

[0008] A wrench for reinstalling the reactor drive rod includes an inner wrench and an outer wrench. The outer wrench is sleeved on the inner wrench and is used to connect and loosen the inner wrench to the drive rod.

[0009] The inner wrench includes an inner wrench sleeve. A protective sleeve is welded to the head of the inner wrench sleeve. Two inner wrench handles are symmetrically welded to the outside of the protective sleeve for rotating the inner wrench. The upper part of the connecting column is connected to the bottom of the inner wrench sleeve by socket welding, and the lower part is connected to a cross universal joint. The lower part of the cross universal joint is connected to a connecting rod. The connecting rod is provided with an external thread section. A locking nut is engaged with the external thread section and is installed on the connecting rod. It can move up and down on the connecting rod by screw rotation. A pin shaft is installed in the through hole at the lower end of the connecting rod and is matched with the "J"-shaped key groove at the head of the driving rod for connecting the wrench and the driving rod.

[0010] Two fan-shaped grooves are symmetrically opened at the upper part of the locking nut.

[0011] A limiting boss is designed at the upper part of the connecting rod, and its maximum diameter is smaller than the inner diameter of the fan-shaped groove, which does not affect the engagement between the outer wrench and the locking nut.

[0012] A positioning screw is installed in the threaded hole at the bottom surface of the connecting rod for fixing the pin shaft.

[0013] The outer wrench is sleeved outside the inner wrench and can move freely up and down on the inner wrench. The upper limit of movement is the lower end surface of the protective sleeve, and the lower limit of movement is the upper end surface of the locking nut.

[0014] The outer wrench includes an outer wrench sleeve, outer wrench handles, and fan-shaped keys. A small section of the head of the outer wrench sleeve has the same diameter as the protective sleeve, and the diameter of the part below the head becomes smaller. Two outer wrench handles are symmetrically welded to the head position of the outer wrench sleeve for rotating the outer wrench. Two symmetric fan-shaped keys are located at the end of the outer wrench sleeve.

[0015] The fan-shaped keys are matched with the fan-shaped grooves and are used to loosen the locking nut after the driving rod is lowered to the installation position.

[0016] There is a chamfer on the inner side of the fan-shaped key.

[0017] The inner wrench sleeve is a hollow pipe fitting structure.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] (1) The present invention provides a reactor drive rod reinstallation wrench.

[0020] Adopting a double-wrench structure design, the space utilization rate is high; the inner and outer wrenches are hollow pipe fitting structures, which greatly reduce the overall weight of the special wrench on the basis of ensuring that the mechanical strength meets the requirements and is convenient for the staff to operate;

[0021] (2) The present invention provides a reactor drive rod reinstallation wrench, which is humanely provided with a protective sleeve. When the inner and outer wrenches are closed together, a proper space is left between the handles of the inner and outer wrenches to prevent the hands of the staff from being pinched.

[0022] (3) The present invention provides a reactor drive rod reinstallation wrench, which introduces a cross universal joint component to realize the relatively free movement of the upper and lower parts of the inner wrench. When the special wrench is connected to the head of the drive rod, the coaxiality requirement of the whole wrench and the drive rod is reduced, greatly improving the connection efficiency and qualification rate of the special wrench and the drive rod.

[0023] (4) The present invention provides a reactor drive rod reinstallation wrench. The anti-loosening design (locking nut) can effectively prevent the event that the special wrench and the drive rod are accidentally disconnected due to shaking during the lowering process of the drive rod, resulting in damage to the drive rod.

[0024] (5) The present invention provides a reactor drive rod reinstallation wrench. In the structural design of the vulnerable parts, the convenience of maintenance is considered. The pin shaft is fixed with a threaded positioning screw, which is convenient for replacing the pin shaft that is deformed or worn after long-term use.

[0025] (6) The present invention provides a reactor drive rod reinstallation wrench. The sector key on the outer wrench and the sector groove on the locking nut are cleverly matched to quickly and efficiently complete the engagement between the outer wrench and the locking nut, realizing the remote unlocking of the locking nut. Description of the Drawings

[0026] Figure 1 It is a schematic diagram of the drive rod structure;

[0027] Figure 2 It is the drive rod wrench in the prior art;

[0028] Figure 3 It is a schematic diagram of the structure of a special wrench for reactor drive rod reinstallation provided by the present invention;

[0029] Figure 4 It is Figure 3 The A-A cross-sectional view in

[0030] Figure 5 It is Figure 3 The B-B cross-sectional view in

[0031] In the figure: 1 - inner wrench, 2 - outer wrench, 3 - inner wrench sleeve, 4 - protective sleeve, 5 - inner wrench handle, 6 - connecting column, 7 - cross universal joint, 8 - connecting rod, 9 - external thread section, 10 - locking nut, 11 - sector groove, 12 - limit boss, 13 - pin shaft, 14 - positioning screw, 15 - flat groove, 16 - outer wrench sleeve, 17 - outer wrench handle, 18 - sector key, 19 - moving rod head. Detailed implementation mode

[0032] The following further elaborates in detail on a reactor drive rod reinstallation wrench provided by the present invention in conjunction with the attached drawings and specific embodiments.

[0033] As Figure 3 shown, a reactor drive rod reinstallation wrench provided by the present invention includes an inner layer wrench 1 and an outer layer wrench 2. The inner and outer layer wrenches cooperate to achieve functions such as reliable connection with the drive rod, lowering of the drive rod, and remote separation of the special wrench from the drive rod.

[0034] The overall appearance of the inner layer wrench 1 is in the shape of a long rod and is used to connect and lock the head of the drive rod.

[0035] The upper part of the inner layer wrench 1 is an inner layer wrench sleeve 3, whose length occupies most of the total length of the inner layer wrench 1. It is a hollow pipe fitting structure, which greatly reduces the overall weight of the special wrench on the basis of ensuring that the mechanical strength meets the requirements and is convenient for the staff to operate.

[0036] A protective sleeve 4 is welded to the head of the inner layer wrench sleeve 3.

[0037] Two inner layer wrench handles 5 are symmetrically welded to the outside of the protective sleeve 4 for rotating the inner layer wrench. The connecting column 6 is a transition section between the upper and lower parts of the inner layer wrench. The upper part is connected to the bottom of the inner layer wrench sleeve 3 by socket welding, and the lower part is connected to the cross universal joint 7.

[0038] The cross universal joint 7 is the core component to realize the relative free movement of the upper and lower parts of the inner layer wrench. A connecting rod 8 is connected to its lower part, enabling the connecting rod 8 to freely and conveniently adjust its position without being restricted by the upper structure of the inner layer wrench. When connecting the wrench to the head of the drive rod, it is only necessary to align the connecting rod 8 with the drive rod coaxially to complete the connection, without the need to adjust the entire inner layer wrench to be on the same axis as the drive rod, which greatly improves the connection efficiency and qualification rate of the special wrench and the drive rod.

[0039] An external thread section 9 is provided on the connecting rod 8. The locking nut 10 meshes with the external thread section 9 and is installed on the connecting rod 8. It can move up and down on the connecting rod 8 by screw rotation. The locking nut 10 mainly plays a role in locking and preventing detachment. After the inner layer wrench is reliably connected to the head of the drive rod, the locking nut 10 is screwed down to press the drive rod, which can effectively prevent the event that the wrench and the drive rod are accidentally disconnected due to shaking during the lowering of the drive rod, resulting in damage to the drive rod. As Figure 5As shown in the figure, two symmetrical sector grooves 11 are opened on the upper part of the locking nut 10, and a limiting boss 12 is designed on the upper part of the connecting rod 8. The maximum diameter of the limiting boss 12 is smaller than the inner diameter of the sector groove 11, which does not affect the engagement of the outer wrench with the locking nut 10. The limiting boss 12 serves as the upper limit of the locking nut 10 to prevent the nut from being loosened excessively and disengaging from the external thread section 9 when the locking nut 10 is loosened. The pin shaft 13 is installed in the through hole at the lower end of the connecting rod 8 and is matched with the "J"-shaped key groove at the head of the driving rod for connecting the wrench and the driving rod. The positioning screw 14 is installed in the threaded hole at the bottom surface of the connecting rod 8. One end of the connecting rod 8 is a conical surface structure that is embedded in the annular groove in the middle of the pin shaft 13 to fix the position of the pin shaft 13. The other end is designed with a flat groove 15, and a flat screwdriver can be used to screw out the positioning screw 14, so as to replace the pin shaft 13 that is deformed or worn after long-term use.

[0040] The overall appearance of the outer wrench 2 also presents as a long rod shape. It is sleeved outside the inner wrench 1 and can move freely up and down on the inner wrench 1. The upper limit of the movement is the lower end surface of the protective sleeve 4, and the lower limit of the movement is the upper end surface of the locking nut 10. The outer wrench 2 is mainly used for the staff to grasp when lowering the driving rod to the installation position, and to loosen the locking nut 10 after the driving rod is placed in place. The outer wrench 2 mainly consists of an outer wrench sleeve 16, an outer wrench handle 17, and a sector key 18. The diameter of a small section at the head of the outer wrench sleeve 16 is the same as the diameter of the protective sleeve 4, so as to leave a proper space between the handles of the inner and outer wrenches when the inner and outer wrenches are closed together, preventing the staff's hands from being pinched. The part of the outer wrench sleeve 16 below the head becomes thinner, effectively reducing the overall weight of the special wrench. Two outer wrench handles 17 are symmetrically welded at the head position of the outer wrench sleeve 16 for rotating the outer wrench 2. As Figure 4 shown, two symmetrical sector keys 18 are located at the end of the outer wrench sleeve 16 and are used in cooperation with the sector groove 11 to realize the engagement of the outer wrench 2 with the locking nut 10. There is a chamfer design on the inner side of the sector key 18 to ensure the quick and efficient engagement of the sector key 18 with the locking nut 10 under the limited condition that the on-site equipment is not visible.

[0041] As Figure 4 shown, the sector groove 11 cooperates with the sector key 18 on the outer wrench to loosen the locking nut 10 after the driving rod is lowered to the installation position.

[0042] The protective sleeve 4 has two functions: on the one hand, it enhances the strength of the head of the inner wrench sleeve 3 to prevent bending and deformation due to bumping; on the other hand, the lower end of the protective sleeve 4 cooperates with the upper end of the outer wrench sleeve 16 to leave a proper space between the handles of the inner and outer wrenches when the inner and outer wrenches are closed together, preventing the staff's hands from being pinched.

[0043] The working principle of the present invention is as follows:

[0044] A staff member vertically holds up the driving rod reinstallation wrench and moves it above the driving rod to be reinstalled. At this time, under the self-weight of the inner wrench 1, the inner and outer wrenches close together, and the part of the inner wrench 1 below the cross universal joint 7 is exposed. Another staff member checks and confirms that the locking nut 10 is in contact with the limit boss 12 (i.e., at the upper limit position). Align the pin shaft 13 on the connecting rod 8 with the "J"-shaped keyway of the driving rod head 19 and insert it to the bottom, then rotate the outer wrench handle 17 clockwise to the end and lift it up, and unscrew the locking nut 10 until it presses against the driving rod head 19, thus completing the reliable connection between the special wrench and the driving rod. During the connection process, the staff member holding the special wrench only needs to ensure that the whole wrench is basically vertical, and there is no strict requirement for the coaxiality between the whole special wrench and the driving rod;

[0045] The staff member responsible for the connection grabs the driving rod fixing fixture, and the staff member holding the wrench slightly lifts the special wrench. After removing the driving rod fixing fixture, slowly lower the wrench connected to the driving rod to the driving rod installation position. There will inevitably be swings during the process, but the locking nut 10 has locked the driving rod, completely eliminating the risk of the driving rod falling off;

[0046] After the driving rod is placed at the installation position, gently lower the outer wrench 2 until the sector key 18 touches the locking nut 10. Rotate the outer wrench 2 counterclockwise until the sector key 18 meshes with the sector groove 11, and continue to rotate the outer wrench 2 counterclockwise until the locking nut 10 rotates to the upper limit position. Rotate the inner wrench 1 counterclockwise to the end and lift it up to disconnect the special wrench from the driving rod, then take out the driving rod reinstallation special wrench to complete the reinstallation work of this driving rod.

[0047] As mentioned above, it is only the preferred specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent replacements or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A reactor drive rod reinstallation wrench, characterized in that: it includes an inner wrench and an outer wrench. The outer wrench is sleeved on the inner wrench and is used to connect and loosen the inner wrench to the drive rod; the inner wrench includes an inner wrench sleeve. A protective sleeve is welded to the head of the inner wrench sleeve. Two inner wrench handles are symmetrically welded to the outside of the protective sleeve for rotating the inner wrench. The upper part of the connecting column is connected to the bottom of the inner wrench sleeve in a socket welding form, and the lower part is connected to a cross universal joint. The lower part of the cross universal joint is connected to a connecting rod. An external thread section is provided on the connecting rod. A locking nut is engaged with the external thread section and is installed on the connecting rod. It can move up and down on the connecting rod by screw rotation. A pin shaft is installed in the through hole at the lower end of the connecting rod and is matched with the "J"-shaped keyway at the head of the drive rod for connecting the wrench to the drive rod; the outer wrench is sleeved outside the inner wrench and can move freely up and down on the inner wrench. The upper limit of the movement is the lower end face of the protective sleeve, and the lower limit of the movement is the upper end face of the locking nut; two symmetrical sector-shaped grooves are opened on the upper part of the locking nut; a limiting boss is designed on the upper part of the connecting rod, and its maximum diameter is smaller than the inner diameter of the sector-shaped groove, which does not affect the engagement between the outer wrench and the locking nut.

2. A reactor drive rod reinstallation wrench according to claim 1, characterized in that: a positioning screw is installed in the threaded hole at the bottom surface of the connecting rod for fixing the pin shaft.

3. A reactor drive rod reinstallation wrench according to claim 2, characterized in that: the outer wrench includes an outer wrench sleeve, outer wrench handles, and sector keys. The diameter of a small section at the head of the outer wrench sleeve is the same as the diameter of the protective sleeve, and the diameter of the part below the head becomes smaller; two outer wrench handles are symmetrically welded to the head position of the outer wrench sleeve for rotating the outer wrench; two symmetrical sector keys are located at the end of the outer wrench sleeve.

4. A reactor drive rod reinstallation wrench according to claim 3, characterized in that: the sector keys are matched with the sector-shaped grooves and are used to loosen the locking nut after the drive rod is lowered to the installation position.

5. A reactor drive rod reinstallation wrench according to claim 4, characterized in that: a chamfer is provided on the inner side of the sector key.

6. A reactor drive rod reinstallation wrench according to claim 1, characterized in that: the inner wrench sleeve is a hollow pipe fitting structure.

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