Method for unhooking a steel cage module of a nuclear power plant

Abstract

The application discloses a method for unhooking a steel reinforcement cage module of a nuclear power plant, and relates to the technical field of nuclear power plant construction, wherein the method comprises the following steps: dividing the steel reinforcement cage module into sections, and controlling the extrusion connection completion proportion of each section to be not less than 50% and the proportion difference of diagonal sections to be not more than 10%; installing an oblique support with adjustable pre-tightening force on the back side of the module and correcting the perpendicularity; uniformly adjusting the stress of a lifting belt connected with a lifting hook and a joist, and releasing the stress step by step; gradually reducing the hook load according to the rated lifting capacity of a tower crane, maintaining the set time length of each stage, and monitoring the module elevation, settlement and support force state, stopping unloading and resuming when an abnormality occurs; unhooking by using a temporary rope preset on an operating frame; continuously monitoring the displacement of the top of the module after unhooking, and if it is determined that the module is unstable, the module is reinforced after being reconnected and loaded, and the load transfer verification and unhooking are performed again. The application realizes smooth and safe load transfer from a lifting tool to a module, and improves the reliability of the unhooking operation of a large steel reinforcement cage module.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plant construction technology, and in particular to a method for unhooking a nuclear power plant steel cage module. Background Technology

[0002] In the construction of the main structure of the nuclear island, the core process for achieving modular construction is to hoist the pre-tied large steel cage modules as a whole and connect them with the pre-reserved vertical steel bars at the bottom.

[0003] However, existing unhooking methods have significant shortcomings. Direct and rapid load unloading can easily cause stress impacts on local connection points before the module connections have developed sufficient strength, potentially leading to connection failure or even structural damage. Furthermore, relying on experience for one-time unhooking lacks refined and quantitative control over the load transfer process, failing to effectively ensure that key state parameters such as verticality and connection stress under the module's own weight smoothly transition and ultimately stabilize within acceptable ranges. Particularly in the construction of large nuclear power plants, where the steel cage modules are massive and have complex stiffness distributions, the current crude unhooking control methods fall far short of the high stability expectations for the module's state during construction. This makes it highly susceptible to irreversible quality and safety accidents such as module tilting and connection cracking due to improper load transfer. Summary of the Invention

[0004] The main objective of this invention is to propose a method for unhooking nuclear power plant steel cage modules, aiming to solve the technical problems in the existing technology where the unhooking process is crude and the load transfer lacks quantitative control, resulting in the modules being susceptible to impact and instability during unloading, causing structural damage.

[0005] To achieve the above objectives, the present invention proposes a method for unhooking nuclear power plant steel cage modules, the method comprising: The steel cage module is divided into no less than 4 sections along its length. After hoisting and positioning and connecting the vertical steel bars with the reserved dowel bars, the vertical steel bars in each section are squeezed and connected, so that the proportion of squeezed connection in all sections is no less than 50% and the proportion difference between diagonal sections is no more than 10%. An oblique support is installed on the back side of the steel cage module, the preload of the oblique support is adjusted, and the verticality of the steel cage module is corrected. The stress uniformity of the multiple slings connecting the tower crane hook and the H-shaped support beam is adjusted, and the stress of the multiple slings is pre-released symmetrically in stages. The load on the tower crane hook is gradually reduced according to the rated lifting capacity of the tower crane. Each load level is maintained for a set time and the status of the steel cage module is monitored. If an abnormality occurs, unloading is stopped and the upper load is restored until all levels are unloaded and the steel cage module is stable. A temporary suspension rope is pre-set on the operating frame. The tower crane hook is lifted so that the shackle connecting the tower crane hook and the H-shaped support beam slides out of the lifting lug. The H-shaped support beam and the multiple slings are then suspended on the operating frame by the temporary suspension rope. After unhooking, the displacement of the top center point of the steel cage module is monitored. If the monitoring deviation exceeds the threshold, the steel cage module is determined to be unstable. The tower crane hook is then reconnected and loaded. After the steel cage module is reinforced, the load transfer verification and unhooking are performed again.

[0006] The technical solution of this invention ensures the overall stress balance and foundation rigidity of the module before unhooking by segmenting the steel cage module and connecting each segment with compression, and limiting the connection completion ratio of diagonal segments. Simultaneously, adjustable pre-tensioning diagonal supports are installed on the back side of the module for verticality correction, creating an active and controllable external stability system for the module. During unhooking, uneven internal forces in the lifting system are eliminated by adjusting the uniformity of force on multiple lifting straps and performing symmetrical step-by-step stress pre-release, allowing the load to initially and smoothly transition from the lifting equipment to the module itself and the support system. Furthermore, the hook load is gradually reduced according to the tower crane's rated lifting capacity, and the load is maintained and monitored at each level. If an abnormality occurs, the load is stopped and the next higher level is restored. This graded, reversible load transfer method with closed-loop monitoring achieves refined and quantitative management of the module's state change process, fundamentally avoiding the risks associated with impact unloading. Finally, by using temporary suspension ropes on the operating frame to detach the hooks and implementing continuous displacement monitoring and reinforcement mechanisms after detachment, the final redundant safety guarantee and long-term stability verification means were provided for the successful implementation of the entire method, significantly improving the safety and reliability of the detachment operation of large steel cage modules in nuclear power plants. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0008] Figure 1 This is a flowchart illustrating an embodiment of the nuclear power plant steel cage module unhooking method provided by the present invention.

[0009] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0010] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0011] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0012] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0013] With the continuous development of nuclear power plant construction technology, modular construction methods have gradually become the mainstream trend in nuclear power plant construction due to their significant advantages in improving project quality, shortening construction cycles, and reducing on-site operational risks. In the construction of the main structure of the nuclear island, the core process for achieving modular construction is the overall hoisting of pre-tied large steel cage modules and their connection with the pre-reserved vertical steel bars at the bottom. This process involves heavy-duty lifting, high-precision docking, and the smooth transfer of loads, making it extremely technically complex and requiring high safety standards.

[0014] Currently, after large steel cage modules are hoisted into place and the initial connection of the reinforcing bars is completed, it is necessary to disconnect the hooks of lifting equipment such as tower cranes from the modules. This process is called "unhooking." The current unhooking method typically involves operators, based on experience, directly unloading the tower crane load and removing the hooks in one go after confirming that some reinforcing bar connections have been completed. In some practices, temporary supports are also added between the module and the surrounding fixed structures before unloading to help maintain the stability of the module.

[0015] However, existing unhooking methods have significant shortcomings. Direct and rapid load unloading can easily cause stress impacts on local connection points before the module connections have developed sufficient strength, potentially leading to connection failure or even structural damage. Furthermore, relying on experience for one-time unhooking lacks refined and quantitative control over the load transfer process, failing to effectively ensure that key state parameters such as verticality and connection stress under the module's own weight smoothly transition and ultimately stabilize within acceptable ranges. Particularly in the construction of large nuclear power plants, where the steel cage modules are massive and have complex stiffness distributions, the current crude unhooking control methods fall far short of the high stability expectations for the module's state during construction. This makes it highly susceptible to irreversible quality and safety accidents such as module tilting and connection cracking due to improper load transfer.

[0016] To address this technical problem, this invention proposes a method for unhooking a nuclear power plant steel cage module.

[0017] Please see Figure 1 In one embodiment of the present invention, the method for unhooking the nuclear power plant steel cage module includes: Step S10: Divide the steel cage module into no less than 4 sections along its length. After hoisting and positioning and connecting the vertical steel bars with the reserved dowel bars, compress and connect the vertical steel bars in each section, so that the proportion of compress and connect in all sections is no less than 50% and the proportion difference between diagonal sections is no more than 10%. Step S20: Install an inclined support on the back side of the steel cage module, adjust the preload of the inclined support, and correct the verticality of the steel cage module. Step S30: Adjust the uniformity of stress on the multiple slings connecting the tower crane hook and the H-shaped support beam, and perform symmetrical step-by-step stress pre-release on the multiple slings; Step S40: Gradually reduce the load on the tower crane hook according to the rated lifting capacity of the tower crane. Maintain the load at each level for a set time and monitor the status of the steel cage module. If an abnormality occurs, stop unloading and restore the upper level load until all levels are unloaded and the steel cage module is stable. Step S50: A temporary suspension rope is preset on the operating frame. The tower crane hook is lifted so that the shackle connecting the tower crane hook and the H-shaped support beam slides out of the lifting lug. The H-shaped support beam and the multiple slings are suspended on the operating frame by the temporary suspension rope. Step S60: After unhooking, the displacement of the top center point of the steel cage module is monitored. If the monitoring deviation exceeds the threshold, the steel cage module is determined to be unstable. The tower crane hook is reconnected and loaded. After the steel cage module is reinforced, the load transfer verification and unhooking are performed again.

[0018] It should be noted that: "Nuclear power plant steel cage module" refers to a large three-dimensional steel skeleton pre-tied and bound at a specific site during the construction of a nuclear power plant. It possesses sufficient rigidity and integrity to withstand the loads during hoisting and placement. "Unhooking" refers to the process of detaching the tower crane hook and its associated lifting equipment from the module. "H-shaped support beam" is a hoisting distribution beam with an H-shaped structure, used to evenly distribute the lifting force of the tower crane from a single point to multiple lifting points on the module. "Vertical reinforcement" refers to the vertical steel bars in the steel cage module. "Extrusion connection" refers to the technique of radially extruding and deforming the connecting sleeve of two steel bars using specialized extrusion equipment, causing the sleeve to tightly interlock with the steel bars to achieve a mechanical connection. "Diagonal section" refers to two diagonally opposite sections after the rectangular module is divided into four equal sections along its length, such as the first and third sections, or the second and fourth sections.

[0019] Specifically, this method first ensures that the module and the lower pre-reserved reinforcing bars have a balanced initial connection strength, then constructs an active and controllable oblique support stabilization system on the back side. Next, it implements balanced stress release on the lifting system, followed by a graded, reversible, and refined unloading process with real-time status feedback. Finally, the hook is safely detached with the assistance of the operating frame, and the stability of the detached module is continuously monitored. This entire logically rigorous process solves the problem of module connection or structural damage due to impact caused by rapid, one-time unloading in traditional hook-removal methods, achieving a safe and gradual transfer of the lifting load of ultra-large tonnage, high-flexibility steel cage modules to the structural body and external support system.

[0020] More specifically, the steel cage module, which has been hoisted into place and whose vertical reinforcement bars have been preliminarily connected to the pre-reserved reinforcement bars in the foundation, must first be divided into at least four sections along its length. For all vertical reinforcement bars in each section, hydraulic extrusion equipment is used to perform extrusion connection construction one by one, ensuring that the percentage of completed extrusion connections in each section is not less than 50% of the total number of vertical reinforcement bars in that section. Simultaneously, to ensure the symmetry and balance of the module's internal stiffness before unhooking, the absolute value of the difference in the completion percentage of extrusion connections between the two diagonally opposite sections must not exceed 10%. Subsequently, on the back side of the steel cage module, i.e., the side that may tilt, one or more sets of diagonal supports with adjustment mechanisms are installed. By adjusting the preload of these supports and using measuring instruments such as a theodolite, the verticality of the module is precisely corrected to bring it within the range allowed by design or specifications. Next, the preload of the multiple slings connecting the tower crane hook and the H-shaped support beam is uniformly adjusted, and part of the preload within the slings is released in stages according to symmetrical groups, allowing for initial unloading of the lifting system. Based on this, the core unloading procedure is initiated, gradually reducing the load on the module from the tower crane hook in multiple levels according to the tower crane's rated lifting capacity. After each preset load level is reached, this load state must be maintained for a preset fixed time, during which various status indicators of the steel cage module, such as verticality, support stress, and changes in connection nodes, must be continuously monitored. If any abnormality is observed during this process, the unloading operation must be stopped immediately, and the hook load restored to the previous safety level. Unloading can only continue from the current level after the cause has been identified, the abnormality eliminated, or reinforcement measures taken. Only after all predetermined load levels have been successfully unloaded and stabilized can the next step be performed. Finally, temporary suspension ropes are set up on the pre-erected operating platform, and the tower crane hook is slowly raised, allowing the shackle connecting the hook and the H-shaped support beam to slide out of the lifting lugs in a shock-free relative movement. This safely transfers the entire lifting spreader system to the operating frame, completing the unhooking process. After unhooking, the three-dimensional displacement of the top center point of the module must be continuously and periodically monitored immediately. The monitored deviation data is compared with the preset stability threshold. If any deviation exceeds the threshold, the module is determined to be in an unstable state. At this time, the tower crane hook must be immediately reconnected to the lifting device of the module and a certain load must be applied to stabilize the situation. The weak parts of the module are reinforced and strengthened. Then, starting from the load equalization adjustment step of the lifting sling, the entire load transfer verification and unhooking procedure is repeated until successful.

[0021] In an embodiment of the present invention, the step of ensuring that the proportion of extrusion connection of all sections is not less than 50% and the proportion difference between diagonal sections is not greater than 10% includes: Step S101: Divide the steel cage module into a first section, a second section, a third section and a fourth section along the length direction. The first section is diagonally opposite to the third section, and the second section is diagonally opposite to the fourth section. Step S102: Perform vertical reinforcement extrusion connection construction segment by segment, taking the aforementioned section as the unit; Step S103: Calculate the proportion of the number of vertical ribs that have been extruded and connected in each section to the total number of vertical ribs in that section; Step S104: If the proportion of any segment is less than 50%, then the segments with insufficient proportion are squeezed and connected until the proportion of all segments is not less than 50%. Step S105: Calculate the ratio difference between the first segment and the third segment, and the ratio difference between the second segment and the fourth segment. If any ratio difference exceeds 10%, adjust the construction progress so that the ratio difference between the diagonal segments does not exceed 10%.

[0022] It should be noted that "Section 1", "Section 2", "Section 3" and "Section 4" are four consecutive regions defined sequentially from one end to the other along the length of the module for ease of management. Section 1 and Section 4 are located at the two ends, and Section 2 and Section 3 are located in the middle.

[0023] Specifically, by segmenting the modules and introducing balanced control of the diagonal segment connection ratio, it is ensured that the modules have a symmetrical and basic mechanical load-bearing frame before the crane load is removed. This avoids torsion or asymmetrical deformation during load transfer due to excessively strong connections on one side and insufficient connections on the other side, thus creating the preconditions for smooth unloading.

[0024] More specifically, the pre-positioned rebar cage modules are first precisely measured and marked, then evenly divided along their length into four sections: Section 1, Section 2, Section 3, and Section 4. At this point, Section 1 and Section 3 are diagonally opposite each other, and Section 2 and Section 4 are diagonally opposite each other in another direction. In terms of construction management, each section is used as a basic work unit, and the vertical reinforcement bars within each section are connected by compression. After each section is completed or during construction, the number of vertical reinforcement bars that have been connected by compression is counted and divided by the total number of vertical reinforcement bars in that section to obtain the real-time compression connection completion rate for each section. Management personnel must continuously check these rates. If the calculated rate for any section is found to be below 50%, construction personnel are immediately arranged to perform additional compression connections on the unconnected vertical reinforcement bars in that section until the rate for all four sections meets the basic requirement of not less than 50%. After meeting the basic requirements, a balance check is also necessary: ​​calculate the ratio difference between the first and third diagonal sections, and simultaneously calculate the ratio difference between the second and fourth sections. If the absolute value of the ratio difference between any pair of diagonal sections exceeds 10%, it indicates a significant asymmetry in the module's connection progress. In this case, it is necessary to adjust the deployment of construction resources and the work plan, suspend construction work in sections with higher connection ratios, and concentrate efforts on squeezing connections in diagonal sections with lower connection ratios until the ratio difference between the two pairs of diagonal sections is controlled to within a range not exceeding 10%, thus achieving a balanced distribution of the module's own connection stiffness.

[0025] In an embodiment of the present invention, the steps of installing an oblique support on the back side of the reinforcing cage module, adjusting the preload of the oblique support, and correcting the verticality of the reinforcing cage module include: Step S201: Drill holes in the ground on the back side of the steel cage module and insert expansion bolts to fix the lower end connecting plate of the inclined support to the ground. Step S202: Weld temporary top support ear plates at 2 / 3 of the height of the rear side facade of the steel cage module; Step S203: Align the upper top support head of the inclined support with the temporary top support ear plate, and apply a tightening torque by rotating the adjusting sleeve of the inclined support so that the supporting force of the inclined support reaches 5000N. Step S204: Use a theodolite to observe the horizontal offset of the top of the steel cage module relative to the bottom. If the offset exceeds 5mm, adjust the adjusting sleeve to change the length of the inclined support to correct the offset until the offset does not exceed 5mm.

[0026] It should be noted that: "Diagonal support" refers to a rod system with one end fixed to the ground or a stable structure and the other end supporting the steel cage module. Its length is adjustable, and it is used to transfer the horizontal inclination force of the module to the ground, maintaining its stability. "Expansion bolt" is a fastener that achieves anchoring in a substrate such as concrete by generating friction through expansion. "Temporary support lugs" are steel plates temporarily welded to the rear facade of the module, used to provide a reliable point of force for the end of the support rod. "Theodolite" is an optical or electronic instrument used for accurately measuring horizontal and vertical angles.

[0027] Specifically, by setting an inclined support with a precise and adjustable preload at a specific height on the back side of the module, and performing closed-loop correction based on feedback from a high-precision measuring instrument, this implementation establishes an external mechanical boundary with clear stiffness and controllable state for the module. This boundary can not only actively correct the initial verticality deviation of the module before unloading, but also continuously resist the lateral displacement that the module may generate after the entire staged unloading and unhooking, greatly enhancing the static stability margin of the system.

[0028] More specifically, firstly, according to the design location, holes are drilled in the ground on the back side of the rebar cage module using an impact drill. Expansion bolts of matching specifications are inserted into the holes and tightened. The connecting plate at the lower end of the inclined support is then securely fixed to the ground anchor point using bolts. Next, on the vertical surface on the back side of the rebar cage module, at a position approximately two-thirds of the total height from its bottom, a temporary top support lug with sufficient strength and rigidity is welded in place using temporary spot welding. Then, the upper top support head of the inclined support is precisely aligned with the center of force of this temporary top support lug. The operator uses a torque wrench to rotate the adjusting sleeve in the middle of the inclined support, gradually applying tightening torque. By using the calibration relationship between torque and axial force, the axial support force generated by the inclined support on the module is controlled to reach the preset value of 5000N. During and after this process, a theodolite is set up at a stable point on the front of the module to accurately measure the horizontal offset of a feature point on the top of the module relative to its bottom reference point. If the observed offset exceeds the allowable deviation of 5mm, it indicates that the module has a vertical deviation exceeding the limit. In this case, the operator needs to fine-tune the adjusting sleeve of the inclined support according to the direction and value of the deviation, changing its axial length to increase or decrease the support force. This change in support force will then slowly push the module to make minor attitude adjustments. After adjustment, the theodolite must be used to observe again, repeating this closed-loop process of "observation-adjustment-re-observation" until the horizontal offset at the top of the module is precisely corrected to within 5mm.

[0029] In an embodiment of the present invention, the step of adjusting the uniformity of force on the multiple slings connecting the tower crane hook and the H-shaped support beam includes: Step S301: Connect the multiple slings to the lifting lugs of the H-shaped support beam via shackles, and connect a sling tension gauge in series at the connection point; Step S302: Measure the actual tension of each of the multiple slings and calculate the average tension value; Step S303: If the actual tension of any sling deviates from the average tension value by more than ±10%, the effective length of the sling is adjusted by rotating the turnbuckle on the sling to bring the actual tension closer to the average tension value, until the deviation of all slings is controlled within ±10%.

[0030] It should be noted that this embodiment specifically defines the step of "adjusting the uniformity of force on multiple slings connecting the tower crane hook and the H-shaped support beam" in S10. In this embodiment, "sling" specifically refers to a flexible synthetic fiber lifting sling or wire rope used to connect the hook and the distribution beam. A "shackle" is a connector used to connect the end of the sling to the lifting lug. A "sling tension gauge" is an instrument connected in series in the sling that can directly measure and display the tension value it receives. A "turnbuckle" is a sling helical buckle that uses threads to adjust its length, used to tighten or loosen the sling.

[0031] Specifically, by accurately measuring and independently adjusting the force on each sling, the tension is evenly distributed near the same pre-calculated reference level. This implementation eliminates the uneven initial stress inside the lifting system caused by factors such as manufacturing errors in sling length and installation differences. It ensures that the H-shaped support beam remains horizontal during unloading, thereby enabling the load to be transmitted and released synchronously and evenly at each lifting point of the module, avoiding module tilting or local overload due to uneven force.

[0032] More specifically, all lifting slings are connected at one end to the corresponding lifting lugs on the H-shaped support beam via shackles, and at the other end to the tower crane hook. During the connection process, a calibrated sling tension gauge is connected in series at a designated position on each sling, usually near the lifting lug or hook. Then, the tower crane slightly raises the hook to fully tighten the slings and allow them to bear all or part of the module's weight. After the readings stabilize, the actual tension value displayed on each sling tension gauge is read and recorded. The arithmetic mean of the actual tension of all slings is calculated as the target benchmark value for this adjustment. Next, a deviation analysis is performed on the actual tension of each sling. If the percentage deviation of the tension value of a sling from the calculated average tension value exceeds ±10%, the sling needs to be adjusted. The adjustment method is to change the effective load-bearing length of the sling by rotating a special turnbuckle pre-installed at a suitable position on the sling. If the tension of the sling is too high, loosen the turnbuckle to increase its effective length and reduce the stress; if the tension is too low, tighten the turnbuckle to shorten its effective length and increase the stress. After each adjustment, reread the tension values ​​of all slings and calculate the new average value. Repeat this "measurement-calculation-adjustment" cycle until the deviation of the actual tension value of all slings from the final average tension value is controlled within the tolerance range of ±10%, thus achieving uniform stress adjustment of the lifting system.

[0033] In an embodiment of the present invention, the step of symmetrically and stepwise pre-releasing stress on the multiple slings includes: Step S310: The two slings located on the first diagonal of the H-shaped support beam are identified as the first group, and the two slings located on the second diagonal are identified as the second group; Step S320: Simultaneously loosen the turnbuckles of the first set of slings to reduce the tension of each of the first set of slings by 20% and maintain this position for 3 minutes, during which time the status of the steel cage module is observed. In step S330, if there is no abnormality, the turnbuckles of the second set of slings are loosened simultaneously, so that the tension of each of the second set of slings is reduced by 20%, and all slings are under 80% of their original tension.

[0034] It should be noted that the "first diagonal" and "second diagonal" refer to the virtual lines formed by two non-adjacent lifting lugs on the plane of the H-shaped support beam. The two lifting straps located at opposite ends of the same diagonal are grouped together, resulting in two groups in total.

[0035] Specifically, after the slings were evenly stressed, a portion of the pre-tension was released synchronously and symmetrically in stages, using two sets of slings on the diagonal as units, to simulate the initial transfer of load from the lifting equipment to the module body. This orderly and symmetrical stress release method effectively verifies the module's immediate response during phased unloading without introducing eccentric moments caused by unilateral or disordered release. It is a low-risk pre-unloading test that lays a stable transition state for subsequent formal staged unloading.

[0036] More specifically, after the load-bearing tension of the S13 slings is evenly adjusted, they are first divided into groups. The two slings located at the ends of the first diagonal of the H-shaped support beam are designated as the first group, and the two slings located at the ends of the other diagonal are designated as the second group. During operation, two or more operators work together to slowly and synchronously loosen the turnbuckles on the two slings in the first group. During the adjustment process, the readings of the tension gauge connected in series with the slings in this group are continuously observed, ensuring that the tension value of these two slings is precisely reduced by 20% synchronously from its initial value. After the reduction is completed, this load condition is maintained for 3 minutes. During this 3-minute maintenance period, the monitoring team, including surveyors and observers, needs to closely monitor the overall and local condition of the rebar cage module, including any abnormal noises, visible deformation or swaying, and the stress condition of the diagonal supports. If the condition is confirmed to be normal throughout the process, the same operating steps are then performed on the second group of slings: synchronously loosening their turnbuckles to reduce their tension value by 20% synchronously as well. After the second set of operations is completed and stability is confirmed, all four slings are now under 80% of their original tension, indicating that the symmetrical step-by-step stress pre-release process has been successfully completed and the module has initially borne part of its own weight.

[0037] In an embodiment of the present invention, the step of progressively reducing the load on the tower crane hook according to the rated lifting capacity of the tower crane, maintaining each load level for a set duration and monitoring the status of the reinforcing cage module, and stopping unloading and restoring the previous load level when an abnormality occurs includes: Step S401: Gradually reduce the hook load to 80%, 60%, 40%, and 20% of the rated lifting capacity; Step S402: Maintain the load at 80%, 60%, and 40% for at least 5 minutes, and at 20% load for at least 10 minutes, during which time measure the elevation difference between the top two ends of the steel cage module and the supporting force of the inclined support. Step S403: If the elevation difference exceeds 3mm, or the vertical settlement of any end of the steel cage module exceeds 2mm, or the support force of the inclined support drops below 3000N, then unloading should be stopped immediately, the hook load should be restored to the previous level, and after inspection and reinforcement, unloading should start again from the current level.

[0038] It should be noted that: "Rated lifting capacity" refers to the maximum safe load that the tower crane is allowed to lift at its current working radius. "Elevation difference" refers to the vertical height difference between the two ends of the top of the module along its length, reflecting the module's torsional tilt state. "Vertical settlement" refers to the downward displacement of a point on the module in the vertical direction, reflecting the overall or partial subsidence of the module.

[0039] Specifically, this implementation constructs a multi-level, reversible, closed-loop unloading process with rigorous status monitoring. The total unloading amount is decomposed into multiple small increments, with sufficient observation time set at each level, ensuring that every change in the module's state is confined to a controllable, minute range. By monitoring the relative elevation difference at the top of the module (reflecting torsion), vertical absolute settlement (reflecting sinking), and the attenuation of the diagonal support force (reflecting the module's self-support), these three key indicators corroborate each other, enabling exceptionally sensitive detection of early signs of module instability. Once any condition is triggered, a reversible operation is immediately executed, restoring the module to the previously verified safe load state. This "safe pause - diagnosis - reinforcement - continuation" logic completely eliminates the risk of irreversible catastrophic accidents.

[0040] More specifically, after stress pre-release, the tower crane operator, under the unified command of the supervisor, manipulates the tower crane to reduce the hook load in four equal increments, based on the tower crane's rated lifting capacity. The target load values ​​are 80%, 60%, 40%, and 20% of the rated lifting capacity, respectively. The unloading process must be carried out step by step. When the load is reduced to 80%, operation is stopped, and this load state is maintained for no less than 5 minutes. During this period, surveyors use precision instruments such as levels to measure the elevation of both ends of the top of the steel cage module along its length, calculate and record the elevation difference between the two points; simultaneously, measuring points are set at key locations at the bottom of the module to monitor for downward vertical displacement. In addition, the axial force gauge values ​​on the inclined supports or the support force values ​​calculated through strain gauges must be recorded. Only when all three conditions are met simultaneously—elevation difference not exceeding 3mm, vertical settlement at either end of the module not exceeding 2mm, and the support force of the inclined supports always remaining above 3000N—is the unloading considered stable for this stage. If any condition exceeds the limit, the commander must immediately issue a "stop unloading" order. The tower crane operator then operates to raise the hook load to the next higher safe load level (if an anomaly occurs at level 80%, restore to the pre-stress-released state). Then, relevant personnel conduct a comprehensive inspection of the abnormal area to identify the cause and reinforce it. After the reinforcement measures are completed and confirmed to be reliable, the unloading and monitoring procedures are restarted from the current level (the level where the anomaly first occurred). If the current level is stable, the load is further reduced to 60% of the next level, and the above maintenance, monitoring, and judgment process is repeated. This process is continued level by level until the load is successfully reduced to 20% and maintained stable for at least 10 minutes, at which point the graded unloading and transfer procedure is successfully completed.

[0041] In an embodiment of the present invention, the step of pre-setting a temporary suspension rope on the operating frame, raising the tower crane hook, causing the shackle connecting the tower crane hook and the H-shaped support beam to slip out of the lifting lug, and suspending the H-shaped support beam and the multiple slings on the operating frame via the temporary suspension rope includes: Step S501: Two temporary suspension ropes are symmetrically installed on the top crossbeam of the operating frame, and the lower ends of the temporary suspension ropes are connected to the suspension holes reserved in the H-shaped support beam through shackles. Step S502: Control the tower crane hook to lift at a constant speed not exceeding 0.5m / min, so that the shackle connected to the tower crane hook slides vertically relative to the lifting lug of the H-shaped support beam until it is completely detached; In step S503, after the shackle slips off, the H-shaped support beam and the multiple slings connected to it are suspended by the temporary suspension ropes, with the suspension height not less than 1m from the top surface of the steel cage module.

[0042] It should be noted that: "Operating frame" refers to a temporary steel structure or scaffolding system built around the module to provide a working platform for personnel. "Temporary suspension rope" is a high-strength rope specifically designed for unhooking and used to temporarily support the weight of the lifting equipment. "Suspension hole" is a hole pre-designed and machined into the H-shaped support beam for this specific suspension function.

[0043] Specifically, by setting suspension points on the stable external structure of the operating frame and employing a slow, impact-free method to passively slip the shackles off the hooks, the weight of the already lightly loaded (H-shaped support beam and slings, already at 20% of rated load) is smoothly transferred from the dynamic tower crane system to the static operating frame. This method completely avoids the operational risks of manually unloading large shackles at high altitudes and ensures that no dynamic impact or disturbance is applied to the already stable module at the last moment of hook removal, achieving absolutely stress-free separation of the lifting equipment and the module.

[0044] More specifically, after all the staged unloading is successfully completed and confirmed to be stable, the operation begins. First, on the sturdy crossbeam at the top of the erected operating frame, select two positions symmetrical to the center of the module, and fix one temporary suspension rope of verified specifications and strength to each position. Securely connect the lower ends of these two temporary suspension ropes to the dedicated suspension holes pre-drilled at the end or side of the H-shaped support beam using matching shackles. At this point, the ropes should be slightly slack and unloaded. Once ready, the commander instructs the tower crane operator to operate, controlling the tower crane hook to smoothly lift upwards at a speed not exceeding 0.5 m / min. As the hook is lifted, the shackles originally connecting the hook to the H-shaped support beam lugs will, under the influence of gravity, experience a downward relative slippage in the vertical direction relative to the lugs. This process must be maintained slowly and uniformly, ensuring that the shackles "slip" out of the lugs in the predetermined direction, rather than suddenly "popping out." Once the shackle has completely slid out of the lifting lug's connection range, the entire weight of the H-shaped support beam and its connected sling system is silently and without impact transferred to the two temporary suspension ropes. At this point, it should be visually confirmed that the support beam is stably suspended and that there is a minimum 1-meter clearance safety distance between its bottom and the top surface of the steel cage module below. At this point, the tower crane hook is completely physically detached from the entire module system.

[0045] In an embodiment of the present invention, the step of monitoring the displacement of the top center point of the rebar cage module after unhooking, and determining that the rebar cage module is unstable if the monitoring deviation exceeds a threshold, includes: Step S601: After the temporary suspension of the lifting device is completed, the three-dimensional coordinates of the top center point are measured for the first time as the initial coordinates; Step S602: After unhooking, measure the current coordinates of the top center point every 2 hours, and calculate the cumulative deviation of the current coordinates from the initial coordinates in the horizontal direction and the cumulative deviation in the vertical direction. Step S603: If the cumulative deviation in the horizontal direction exceeds 3mm, or the cumulative deviation in the vertical direction exceeds 2mm, or the deviation increment between two consecutive measurements exceeds 1mm, then the steel cage module is determined to be in an unstable state.

[0046] It should be noted that: the "top center point" refers to a feature point pre-marked at the geometric center of the top surface of the steel cage module, serving as a reference for displacement monitoring. "Three-dimensional coordinates" refers to the X (horizontal), Y (horizontal), and Z (vertical) coordinates of this point in space. "Cumulative deviation" refers to the total change in the point's position since the first measurement. "Deviation increment" refers to the change in position between two adjacent measurements.

[0047] Specifically, by establishing a long-term, timed, multi-dimensional displacement monitoring system with the initial coordinates as the zero point after unhooking, the final confirmation of the module's stability was achieved. The monitoring not only focuses on the absolute total amount of deformation (cumulative deviation) but also on its trend and rate of change (the increment of deviation between two consecutive measurements). This setup effectively distinguishes between creep in a stable state and accelerated deformation in an unstable state, providing a highly sensitive and reliable quantitative basis for determining whether the module is truly stable. It serves as the last crucial line of defense against slow, delayed overturning of the module within hours of unhooking.

[0048] More specifically, after the lifting equipment has been temporarily suspended, the tower crane hook has been completely detached, and it has been confirmed that there are no other interferences on site, a high-precision three-dimensional coordinate measuring device such as a total station is immediately used to conduct the first accurate three-dimensional coordinate measurement of the pre-marked center point on the top of the rebar cage module. This measurement value is recorded and saved as the baseline "initial coordinates." After all the hook removal operations are completed, a long-term stability monitoring cycle begins. The monitoring plan is as follows: every 2 hours, the same equipment and the same surveyor perform a coordinate measurement of the center point. After each measurement, the horizontal projection distance between the "current coordinates" and the "initial coordinates" is immediately calculated to obtain the cumulative horizontal deviation; at the same time, the vertical coordinate difference is calculated to obtain the cumulative vertical deviation. In addition, the coordinates of this measurement are compared with the coordinates of the previous measurement (i.e., 2 hours ago) to calculate the deviation increment between the two measurements. The three calculation results are compared with the preset stability threshold for judgment: if the cumulative deviation in the horizontal direction exceeds 3mm, or the cumulative deviation in the vertical direction exceeds 2mm, or the deviation increment between two consecutive measurements (regardless of whether it is horizontal or vertical component) exceeds 1mm, as long as any of the above conditions are met, the steel cage module is immediately determined to be in an unstable state and the emergency response procedure must be initiated.

[0049] In an embodiment of the present invention, the steps of reconnecting and loading the tower crane hook, reinforcing the steel cage module, and then re-verifying the load transfer and unhooking the crane include: Step S610: After determining that the steel cage module is unstable, reconnect the tower crane hook to the H-shaped support beam and load the steel cage module to 50% of its own weight. Step S620: After maintaining the load for at least 5 minutes and confirming stability, perform additional extrusion connections on the section with the lowest extrusion connection completion rate, and re-tighten the inclined support to restore the support force to at least 5000N. Step S630: After reinforcement is completed, the uniformity of sling stress, symmetrical step-by-step stress pre-release, and graded load transfer verification are carried out again. After the verification is qualified, the hook is unhooked and subsequent displacement monitoring is carried out again.

[0050] It should be noted that "reinforcement" refers to adding additional connection points, increasing support force, or adding auxiliary structures to the existing connection or support system to enhance the stability and load-bearing capacity of the module.

[0051] Specifically, when the monitoring determines that the module is unstable, this implementation provides a clear, safe, and closed-loop emergency response and remedial plan. Its core principle is "stabilize first, then reinforce, and start over." First, the hook is reinserted and a safe, conservative load is provided to quickly suppress the module's instability trend and restore it to a known safe state. Then, precise reinforcement is carried out on the weak points. Furthermore, the entire load transfer and unhooking process after reinforcement must be re-verified from the initial steps. This ensures that the effectiveness of any reinforcement measures has undergone the same rigorous and complete testing, eliminating the possibility of patching a failed process and fundamentally guaranteeing the success rate and absolute safety of the second attempt.

[0052] More specifically, once a module is determined to be unstable, the on-site commander must immediately activate the emergency plan. The first step is "stabilization": immediately instruct the tower crane to slowly lower the hook and reconnect it to the lifting lug of the H-shaped support beam suspended under the operating frame. After the connection is secure, slowly raise the hook and apply load until the load value of the hook reaches 50% of the pre-calculated self-weight of the steel cage module. Maintain this load state for no less than 5 minutes and continuously observe the module's state to confirm that the instability has disappeared and the module has stabilized. The second step is "reinforcement": under the stable load state, organize construction personnel to carry out supplementary compression connection construction on the sections with the lowest completion rate of compression connections in the early construction; at the same time, use tools to re-tighten the diagonal supports on the back side to ensure that the support force they provide is restored to and stabilized at a level of no less than 5000N. The third step is "retesting": after all reinforcement work is completed and inspected and confirmed to be qualified, the module is considered to have been restored to the initial state that meets the conditions for hook removal. At this point, all current intermediate progress must be abandoned, and the process must be rewound, starting from "adjusting the uniformity of stress on the multiple slings connecting the tower crane hook and the H-shaped support beam." The entire load transfer process—symmetrical step-by-step stress pre-release and graded load transfer verification—must be rigorously and progressively re-executed. Only when all monitoring indicators pass this new verification can the hook removal operation and subsequent displacement monitoring be performed again.

[0053] In an embodiment of the present invention, after the hook is removed, displacement monitoring is performed on the top center point of the rebar cage module. If the monitoring deviation exceeds a threshold, the rebar cage module is determined to be unstable. The tower crane hook is then reconnected and loaded. After reinforcing the rebar cage module, the load transfer verification and hook removal are performed again. The method for removing the rebar cage module from the nuclear power plant further includes: Step S61: Release the temporary suspension ropes and hoist the H-shaped support beam and the multiple slings to the ground for inspection and repair; Step S62: Cut and remove the temporary top support ear plate on the back side of the steel cage module, and grind the remaining weld seam smooth.

[0054] It should be noted that "cutting and dismantling" refers to removing temporarily welded components using tools such as angle grinders and gas cutters. "Grinding and smoothing" refers to using tools such as grinding wheels to smooth out any remaining weld scars and burrs after cutting, making the surface of the base material smooth and avoiding stress concentration and safety hazards.

[0055] Specifically, this step involves the standardized cleaning and restoration of construction support facilities after confirming that the module has passed all stability tests and achieved permanent self-sufficiency. Removing and hoisting the temporary suspension system releases the additional load on the operating frame; cutting and grinding the temporary ear plates restores the structural surface, eliminates obstacles that could interfere with subsequent construction (such as concrete pouring), and removes potential long-term quality hazards caused by weld corrosion. This demonstrates the integrity of the construction process and a responsible attitude towards the quality of the permanent project.

[0056] More specifically, implementation must be carried out only after the module has been monitored for a specified period following unhooking and is deemed completely stable. The first step involves high-altitude workers disconnecting the two temporary suspension ropes from the suspension holes of the H-shaped support beam and tidying the ropes. Subsequently, a tower crane or other auxiliary lifting equipment lifts the suspended H-shaped support beam and its multiple slings to a designated maintenance area on the ground. Specialized personnel conduct a comprehensive inspection of their structure and components, repairing or replacing any damage or deformation incurred during this operation for future use. The second step involves qualified welders and grinders using tools such as gas cutters or angle grinders to cut and remove all temporary support plates welded to the back facade of the steel cage module. Care must be taken to avoid damaging the module's main load-bearing steel bars during cutting. After the ear plates were removed, a handheld grinder was immediately used to finely grind the remaining welds on the surface of the module structure until they were flush with and smooth with the surrounding base material surface, with no obvious protrusions or pits visible. This was then inspected by quality control personnel to ensure that the requirements for subsequent corrosion protection and non-destructive testing were met. At this point, the unhooking operation of the nuclear power plant's steel cage module was completed.

[0057] The above description is merely an exemplary embodiment of the present invention and does not limit the scope of protection of the present invention. Any equivalent structural transformations made based on the technical concept of the present invention and the contents of the specification and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present invention.

Claims

1. A method for unhooking a nuclear power plant steel cage module, characterized in that, The method for unhooking the nuclear power plant steel cage module includes: The steel cage module is divided into no less than 4 sections along its length. After hoisting and positioning and connecting the vertical steel bars with the reserved dowel bars, the vertical steel bars in each section are squeezed and connected, so that the proportion of squeezed connection in all sections is no less than 50% and the proportion difference between diagonal sections is no more than 10%. An oblique support is installed on the back side of the steel cage module, the preload of the oblique support is adjusted, and the verticality of the steel cage module is corrected. The stress uniformity of the multiple slings connecting the tower crane hook and the H-shaped support beam is adjusted, and the stress of the multiple slings is pre-released symmetrically in stages. The load on the tower crane hook is gradually reduced according to the rated lifting capacity of the tower crane. Each load level is maintained for a set time and the status of the steel cage module is monitored. If an abnormality occurs, unloading is stopped and the upper load is restored until all levels are unloaded and the steel cage module is stable. A temporary suspension rope is pre-set on the operating frame. The tower crane hook is lifted so that the shackle connecting the tower crane hook and the H-shaped support beam slides out of the lifting lug. The H-shaped support beam and the multiple slings are then suspended on the operating frame by the temporary suspension rope. After unhooking, the displacement of the top center point of the steel cage module is monitored. If the monitoring deviation exceeds the threshold, the steel cage module is determined to be unstable. The tower crane hook is then reconnected and loaded. After the steel cage module is reinforced, the load transfer verification and unhooking are performed again.

2. The method for unhooking a nuclear power plant steel cage module as described in claim 1, characterized in that, The step of ensuring that the extrusion connection completion rate of all sections is not less than 50% and the ratio difference between diagonal sections is not greater than 10% includes: The steel cage module is divided into a first section, a second section, a third section, and a fourth section along its length. The first section is diagonally opposite to the third section, and the second section is diagonally opposite to the fourth section. The vertical reinforcement extrusion connection construction is carried out segment by segment, taking the aforementioned sections as units; The proportion of the number of vertical reinforcement bars that have been extruded and connected in each section to the total number of vertical reinforcement bars in that section is calculated. If the proportion of any segment is less than 50%, then the segments with insufficient proportion are squeezed and connected until the proportion of all segments is not less than 50%. Calculate the ratio difference between the first segment and the third segment, and the ratio difference between the second segment and the fourth segment. If any ratio difference exceeds 10%, adjust the construction progress so that the ratio difference between the diagonal segments does not exceed 10%.

3. The method for unhooking a nuclear power plant steel cage module as described in claim 1, characterized in that, The steps of installing diagonal supports on the back side of the rebar cage module, adjusting the preload of the diagonal supports, and correcting the verticality of the rebar cage module include: Drill holes in the ground on the back side of the steel cage module and insert expansion bolts to fix the lower end connecting plate of the inclined support to the ground; Temporary top support plates are welded at 2 / 3 of the height of the rear side facade of the steel cage module; Align the upper top support head of the inclined support with the temporary top support ear plate, and apply a tightening torque by rotating the adjusting sleeve of the inclined support so that the supporting force of the inclined support reaches 5000N. The horizontal offset of the top of the steel cage module relative to the bottom is observed using a theodolite. If the offset exceeds 5mm, the length of the inclined support is adjusted by adjusting the adjusting sleeve to correct the offset until the offset does not exceed 5mm.

4. The method for unhooking a nuclear power plant steel cage module as described in claim 1, characterized in that, The step of adjusting the uniformity of force on the multiple slings connecting the tower crane hook and the H-shaped support beam includes: The multiple slings are connected to the lugs of the H-shaped support beam via shackles, and a sling tension gauge is connected in series at the connection point; Measure the actual tension of each of the multiple slings and calculate the average tension value; If the actual tension of any sling deviates from the average tension value by more than ±10%, the effective length of the sling is adjusted by rotating the turnbuckle on that sling to bring the actual tension closer to the average tension value, until the deviation of all slings is controlled within ±10%.

5. The method for unhooking a nuclear power plant steel cage module as described in claim 4, characterized in that, The step of symmetrically and stepwise stress pre-release of the multiple slings includes: The two slings located on the first diagonal of the H-shaped support beam are designated as the first group, and the two slings located on the second diagonal are designated as the second group; Simultaneously loosen the turnbuckles of the first set of slings to reduce the tension of each sling by 20%, and maintain this position for 3 minutes, during which time observe the status of the steel cage module. If there is no abnormality, loosen the turnbuckles of the second set of slings simultaneously, so that the tension of each of the second set of slings is reduced by 20%, and all slings are under 80% of their original tension.

6. The method for unhooking a nuclear power plant steel cage module as described in claim 1, characterized in that, The steps of progressively reducing the load on the tower crane hook according to the rated lifting capacity of the tower crane, maintaining each load level for a set duration and monitoring the status of the reinforcing cage module, stopping unloading and restoring the previous load level when an abnormality occurs include: The hook load was gradually reduced to 80%, 60%, 40%, and 20% of the rated lifting capacity. The load was maintained for at least 5 minutes at 80%, 60%, and 40% load levels, and for at least 10 minutes at 20% load level, during which the elevation difference between the top two ends of the steel cage module and the support force of the inclined support were measured. If the elevation difference exceeds 3mm, or if any end of the steel cage module experiences vertical settlement exceeding 2mm, or if the support force of the inclined support drops below 3000N, unloading should be stopped immediately, the hook load restored to the previous level, and unloading restarted from the current level after inspection and reinforcement.

7. The method for unhooking a nuclear power plant steel cage module as described in claim 1, characterized in that, The steps of pre-setting temporary suspension ropes on the operating frame, raising the tower crane hook, causing the shackle connecting the tower crane hook and the H-shaped support beam to slip out of the lifting lug, and suspending the H-shaped support beam and the multiple slings on the operating frame via the temporary suspension ropes include: Two temporary suspension ropes are symmetrically installed on the top crossbeam of the operating frame, and the lower ends of the temporary suspension ropes are connected to the suspension holes reserved in the H-shaped support beam through shackles. Control the tower crane hook to lift at a constant speed not exceeding 0.5 m / min, so that the shackle connected to the tower crane hook slides vertically relative to the lifting lug of the H-shaped support beam until it is completely detached; After the shackle slips off, the H-shaped support beam and the multiple slings connected to it are then suspended by the temporary suspension ropes, with the suspension height not less than 1m from the top surface of the steel cage module.

8. The method for unhooking a nuclear power plant steel cage module as described in claim 1, characterized in that, The step of monitoring the displacement of the top center point of the rebar cage module after unhooking, and determining that the rebar cage module is unstable if the monitoring deviation exceeds a threshold, includes: After the temporary suspension of the lifting device is completed, the three-dimensional coordinates of the top center point are measured for the first time as the initial coordinates. After unhooking, the current coordinates of the top center point are measured every 2 hours, and the cumulative deviation of the current coordinates from the initial coordinates in the horizontal direction and the cumulative deviation in the vertical direction are calculated. If the cumulative deviation in the horizontal direction exceeds 3mm, or the cumulative deviation in the vertical direction exceeds 2mm, or the deviation increment between two consecutive measurements exceeds 1mm, the steel cage module is determined to be in an unstable state.

9. The method for unhooking a nuclear power plant steel cage module as described in claim 8, characterized in that, The steps of reconnecting and loading the tower crane hook, reinforcing the steel cage module, and then re-verifying the load transfer and unhooking the crane include: After determining that the steel cage module is unstable, the tower crane hook is reconnected to the H-shaped support beam, and the load is increased to 50% of the steel cage module's own weight. After maintaining the load for at least 5 minutes and confirming stability, perform additional extrusion connections on the section with the lowest completion rate of the extrusion connection, and re-tighten the inclined support to restore the support force to at least 5000N. After reinforcement, the uniformity of sling stress, symmetrical step-by-step stress pre-release, and graded load transfer verification were carried out again. After the verification was qualified, the hook was removed and subsequent displacement monitoring was carried out again.

10. The method for unhooking a nuclear power plant steel cage module as described in any one of claims 1 to 9, characterized in that, After unhooking, displacement monitoring is performed on the top center point of the rebar cage module. If the monitoring deviation exceeds a threshold, the rebar cage module is determined to be unstable. The tower crane hook is then reconnected and loaded. After reinforcing the rebar cage module, the load transfer verification and unhooking are performed again. The method for unhooking the nuclear power plant rebar cage module further includes: Release the temporary suspension ropes and hoist the H-shaped support beam and the multiple slings to the ground for inspection and repair; The temporary support ear plate on the back side of the steel cage module is cut and removed, and the remaining weld is ground smooth.

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