Nuclear power station fuel assembly four-side inspection equipment and hoisting mechanism thereof

Abstract

The utility model discloses four-side inspection equipment for a nuclear power station fuel assembly and a hoisting mechanism of the four-side inspection equipment, and belongs to the technical field of pool side inspection equipment. The hoisting mechanism comprises a lower mounting frame, and the lower mounting frame is used for mounting a detection mechanism; a plurality of chains are connected between the upper hoisting frame and the lower mounting frame, the upper hoisting frame is used for hoisting the lower mounting frame and the detection mechanism, and a hoisting ring connected with a crane is arranged on the upper hoisting frame; the supporting base frame is fixedly installed above the conveying pool, and lock chain holes which correspond to the lock chains and enable the lock chains to penetrate in a sliding mode are formed in the supporting base frame; and the supporting base frame can be used for supporting the upper hoisting frame. According to the scheme, the upper hoisting frame is supported through the supporting base frame, so that a crane does not need to work for a long time. And meanwhile, downward movement of the chain can be guided, so that the accuracy of the putting position is improved.

Description

Technical Field

[0001] This utility model relates to the technical field of poolside inspection equipment, and more specifically, to a four-sided inspection device for fuel assemblies in nuclear power plants. Background Technology

[0002] With the increasingly widespread application of nuclear energy, the safe operation and efficient maintenance of nuclear facilities are of paramount importance. To ensure the safe operation of nuclear facilities, it is necessary to accurately obtain information on their operating status, lifespan, and wear condition. Due to the characteristics of nuclear fuel, poolside inspection (also known as underwater inspection) is typically employed. Poolside inspection technology mainly consists of visual inspection techniques, dimensional measurement techniques, and ultrasonic leak detection techniques, among which visual inspection is the most direct and commonly used.

[0003] Among the aforementioned visual inspection techniques, the four-sided inspection method for fuel assemblies is characterized by its good effectiveness and relatively simple operation, and therefore it is widely used in nuclear power plant equipment maintenance and repair.

[0004] Typically, before visual inspection, the inspection equipment needs to be sent to the environment where the object to be inspected is located. Since the environment where the object to be inspected is located has strong radiation and is underwater, it is impossible to transport the equipment manually. In this case, a corresponding hoisting mechanism needs to be designed to meet the transportation requirements.

[0005] Existing nuclear power plant sites typically use a combination of gantry cranes and slings to transport four-sided inspection equipment. This method can only adjust the lifting speed and cannot precisely control the placement of the four-sided inspection equipment in the water.

[0006] However, positioning devices that improve the accuracy of underwater object placement are generally relatively complex. For example, Chinese Patent Application No. 2022111561076 provides a positioning device for hoisting equipment. This device positions the hoisting equipment during the process of lifting components to a predetermined position. It includes an image acquisition unit, an image processing unit, and a position adjustment unit. The image acquisition unit acquires a target image of the predetermined position and transmits it to the image processing unit. The image processing unit calculates the position information of the hoisting equipment relative to the predetermined position based on the information in the target image and transmits the position information to the position adjustment unit. The position adjustment unit adjusts the position of the hoisting equipment based on the position information. This application utilizes machine vision to meet the precise positioning and guidance requirements during underwater hoisting of equipment used in nuclear power plants, but its control process is relatively complex.

[0007] In addition, during the four-sided inspection of the fuel assembly, the camera and the fuel assembly need to move relative to each other along the axis of the fuel assembly to complete the visual inspection. The suspended four-sided inspection equipment cannot be fixed and locked, so the hoisting mechanism needs to work for a long time, which increases the risk of foreign objects on the crane. Utility Model Content

[0008] 1. Technical problems to be solved

[0009] To address the issues of excessive crane operation time and the inability to directly and precisely control the placement position during the four-sided inspection of fuel assemblies in existing technologies, this solution provides equipment and its lifting mechanism for four-sided inspection of nuclear power plant fuel assemblies. This solution adds a support frame and provides support and restraint to the upper lifting frame, thus eliminating the need for prolonged crane operation. Simultaneously, the chain lock holes in the support frame guide the downward movement of the chain, improving the accuracy of the placement position.

[0010] 2. Technical Solution

[0011] The first aspect of this utility model provides a hoisting mechanism for four-sided inspection of fuel assemblies in a nuclear power plant, comprising a lower mounting frame for mounting an inspection mechanism; an upper hoisting frame, wherein multiple chains connect the upper hoisting frame and the lower mounting frame for hoisting the lower mounting frame and the inspection mechanism, and the upper hoisting frame is provided with a crane lifting ring for connecting to a crane; and a support base frame, which is fixedly installed above the transfer pool and has chain holes machined thereon corresponding to the multiple chains and allowing the chains to slide through; and the support base frame can be used to support the upper hoisting frame.

[0012] Furthermore, the support frame includes two parallel and spaced support rods, which straddle the transmission pool and are fixedly connected to the base of the transmission pool. Each of the two support rods has a corresponding chain hole, and the upper hoisting frame and the lower mounting frame are connected by four chains.

[0013] Furthermore, the two support rods are fixedly connected at the same end by a support connecting rod to form a U-shaped support base frame.

[0014] Furthermore, the two support rods and the support connecting rod are fixedly connected to the groove and the protrusion in the base of the transmission pool.

[0015] Furthermore, an opening groove is provided on the opposite side of the chain hole, and the chain enters the opening groove of the chain hole; the hoisting mechanism also includes a plurality of chain limiting parts corresponding to the chain holes, which are used to restrict the chain from coming out of the chain holes.

[0016] Furthermore, the chain limiting part includes a limiting lock piece, which has a limiting slot nested outside the chain.

[0017] Furthermore, the chain limiting part also includes a knurled collar, which is nested inside the chain hole and has a lateral opening groove for the chain to enter its interior.

[0018] Furthermore, the knurled collar includes connected knurled segments and annular segments. The annular segment of the knurled collar is nested in the chain hole, and the outer diameter of the knurled segment is larger than the inner diameter of the chain hole. The top of the knurled segment supports the limiting lock plate.

[0019] Furthermore, the lower mounting frame is configured to correspond with the upper hoisting frame.

[0020] The second aspect of this utility model provides a device for four-sided inspection of fuel assemblies in nuclear power plants, including an inspection mechanism and the aforementioned hoisting mechanism, wherein the inspection mechanism is mounted on a lower mounting frame.

[0021] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0022] (1) This utility model adds a supporting base frame with a chain hole corresponding to the chain, and the chain is slidably disposed in the chain hole. As the chain descends to a preset height, the upper hoisting frame contacts the supporting base frame, thereby limiting the chain's continued descent and preventing it from falling off below the chain hole; at the same time, the chain and the lower mounting frame connected below it are supported and limited at the preset height, so that the crane does not need to operate for a long time. In addition, the chain hole can guide the downward movement of the chain, thereby improving the accuracy of the deployment position.

[0023] (2) This utility model further optimizes the specific structure of the support frame, which includes two parallel and spaced support rods, occupying little space. Furthermore, the support frame adopts a split design for easy transportation. Additionally, a support connecting rod is added between the same ends of the two support rods to improve the overall stability of the support frame. Moreover, the end of the support rod connected to the support connecting rod protrudes upward to form a connecting groove, further increasing the contact area between the support rod and the transmission pool base, thereby improving the stability of the fixed installation in the transmission pool.

[0024] (3) The present invention further designs the chain hole by providing an opening groove that communicates with the opposite side of the chain hole, thereby facilitating the chain to pass through the chain hole. Furthermore, a chain limiting part is added to prevent the chain from slipping out of the chain hole. Even further, by adding a knurled collar in the chain hole and optimizing the specific structure of the knurled collar, the circular segment of the knurled collar is nested in the chain hole, precisely defining the position of the chain in the chain hole. The outer diameter of the knurled segment is larger than the inner diameter of the chain hole, and the end of the knurled segment supports the limiting locking plate, thereby increasing the support area for the limiting locking plate. Attached Figure Description

[0025] Figure 1 This is an overall schematic diagram of the equipment for inspecting the four sides of a nuclear power plant fuel assembly in an embodiment of this utility model.

[0026] Figure 2 This is a three-dimensional structural diagram of the supporting base frame and the chain limiting part in an embodiment of this utility model.

[0027] Figure 3 This is a three-dimensional structural diagram of the supporting frame and the chain limiting part from another perspective of an embodiment of the present utility model.

[0028] Figure 4 for Figure 2 Enlarged schematic diagram of a local structure.

[0029] Figure 5 This is a partial structural diagram of the support rod in an embodiment of the present invention.

[0030] Figure 6 This is a three-dimensional structural diagram of the chain limiting part in use in an embodiment of this utility model.

[0031] Figure 7 This is a partial structural diagram of the chain limiting part in use in an embodiment of this utility model.

[0032] Figure 8 This is a three-dimensional structural diagram of the upper hoisting frame in an embodiment of the present utility model.

[0033] Figure 9 This is a three-dimensional structural diagram of the lower mounting frame and the detection mechanism in an embodiment of this utility model.

[0034] Figure 10 This is a schematic diagram of the planar structure of the lamp support plate in an embodiment of this utility model.

[0035] Figure 11 This is a three-dimensional structural diagram of the lamp connecting support rod in an embodiment of this utility model.

[0036] Label Explanation:

[0037] 1. Support frame; 101. Support rod; 1011. Connecting groove; 102. Chain lock hole; 103. Support connecting rod;

[0038] 2. Upper lifting frame; 201. Crane lifting ring; 202. Chain lifting ring;

[0039] 3. Chains;

[0040] 4. Lower mounting frame; 401. Chain lower lifting ring;

[0041] 5. Chain limiting part; 501. Limiting lock plate; 5011. U-shaped groove; 5012. Long strip groove; 5013. Circular groove; 502. Knurled collar; 5021. Knurled section; 5022. Circular section;

[0042] 6. Testing agency; 601. Testing camera; 602. Lamp support plate; 6021. Base frame connection hole; 6022. Support rod connection hole; 603. Lamp connecting support rod; 6031. Lamp connection hole; 604. Lamp. Detailed Implementation

[0043] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and embodiments.

[0044] The structures, proportions, and sizes illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this utility model. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0045] refer to Figure 1 As shown, this embodiment provides a hoisting mechanism for four-sided inspection of fuel assemblies in a nuclear power plant, including a lower mounting frame 4 for mounting an inspection mechanism 6; an upper hoisting frame 2, with multiple chains 3 connected between the upper hoisting frame 2 and the lower mounting frame 4 for hoisting the lower mounting frame 4 and the inspection mechanism 6, and the upper hoisting frame 2 is provided with a crane lifting ring 201 for connecting to a crane; and a support base frame 1, which is fixedly installed above the transfer pool, and has chain holes 102 machined on it corresponding to the multiple chains 3 and allowing the chains 3 to slide through; and the support base frame 1 can be used to support the upper hoisting frame 2.

[0046] This invention utilizes a chain hole 102 in the support frame 1, which serves the following purpose: the chain 3 passes through the chain hole 102 in the support frame 1 and can slide within it, descending to a preset position. During the movement of the chain 3 relative to the chain hole 102, the chain hole 102 guides the downward movement of the chain 3, improving the positioning accuracy of the lower mounting frame 4 and ensuring the relative positional accuracy between the chains 3. Furthermore, the support frame 1 can be used to support the upper lifting frame 2. Specifically, during the downward movement of the upper lifting frame 2, when the upper lifting frame 2 contacts the support frame 1, it restricts the further downward movement of the upper lifting frame 2, thereby ensuring the uniform downward position of the chain 3 in the transmission pool.

[0047] The lower mounting frame 4 has a passage for the fuel assembly to enter, and the fuel assembly passes through the interior of the lower mounting frame 4 to enter the inspection range of the detection mechanism 6.

[0048] The fuel assembly is generally a cuboid with a square cross-section. As a preferred embodiment of the supporting frame 1, refer to... Figure 2 , Figure 3 As shown, the support frame 1 includes two parallel and spaced support rods 101. The support rods 101 span over the transmission pool and are fixedly connected to the base of the transmission pool. Each of the two support rods 101 has two chain holes 102, that is, the four chain holes 102 in the two support rods 101 are located at the four vertices of the rectangle. The upper hoisting frame 2 and the lower mounting frame 4 are connected by four chains 3.

[0049] The supporting frame 1 includes two parallel and spaced-apart support rods 101. This split design facilitates transportation. Moreover, the two support rods 101 occupy less space, reducing the probability of collisions with other components.

[0050] It should be noted that during the inspection process, the fuel assembly moves vertically within the cuboid space enclosed by the four chains 3, and passes between adjacent chains 3 to exit the inspection device. Correspondingly, the rectangle formed by the four chain holes 102 is much larger than the cross-section of the fuel assembly, meaning the rectangle formed by the four chains 3 is much larger than the cross-section of the fuel assembly. Furthermore, the length of the chains 3 is much greater than the height of the fuel assembly, providing sufficient upward travel distance between the chains 3. Therefore, the fuel assembly has ample space to move, enabling safe and efficient completion of the inspection.

[0051] Preferably, the support rod 101 is elongated and has hollow holes inside to reduce its weight.

[0052] It should be understood that the specific structure of the support frame 1 is not limited by the above-mentioned structure, and the opening position and number of the chain hole 102 in the support rod 101 are not limited by the above-mentioned structure.

[0053] To improve the overall stability of the support frame 1, two support rods 101 are fixedly connected at the same end by a support connecting rod 103 to form a U-shaped support frame. Specifically, the two support rods 101 have connecting grooves on opposite sides, and both ends of the support connecting rod 103 are inserted into the connecting grooves of the two support rods 101 respectively. The connecting grooves match the shape of the support connecting rod 103 to increase the contact area, thereby further improving the stability of the connection between the two support rods 101. Preferably, the cross-section of the support connecting rod 103 is rectangular to prevent the support connecting rod 103 from rotating in the connecting groove.

[0054] More preferably, there are two support connecting rods 103, which are arranged in parallel and spaced vertically, thereby further improving the stability of the connection between the two support rods 101.

[0055] To improve the stability of the connection between the support rod 101 and the transmission pool base, the ends of the two support rods 101 connected to the support connecting rod 103 protrude upward to form a connecting groove 1011. The connecting groove 1011 is fixedly connected to the protrusion in the transmission pool base, thereby increasing the contact area between the support rod 101 and the transmission pool base and improving the connection stability between the support rod 101 and the transmission pool base.

[0056] To facilitate the entry of the chain 3 into the chain hole 102, the two support rods 101 are provided with openings that communicate with the opposite side of the chain hole 102. The chain 3 enters the chain hole 102 through the openings that communicate with the chain hole 102.

[0057] To prevent the chain 3 from slipping out of the chain hole 102, the lifting mechanism also includes multiple chain limiting parts 5 corresponding to the chain holes 102, wherein the number of chain limiting parts 5 corresponds one-to-one with the number of chain holes 102. The chain limiting parts 5 are used to restrict the chain 3 from slipping out of the chain hole 102. Specifically, the chain limiting parts 5 are used to prevent the chain 3 from slipping out through the opening slot of the chain hole 102.

[0058] In some embodiments, reference Figures 4-7 As shown, the chain limiting part 5 includes a limiting locking plate 501, which has a limiting groove fitted onto the outside of the chain 3. Specifically, the limiting groove in the limiting locking plate 501 consists of a U-shaped groove 5011 and an elongated groove 5012 connected in sequence. The opening diameter of the U-shaped groove 5011 is larger than the opening diameter of the elongated groove 5012. A circular groove 5013 is provided at one end of the elongated groove 5012 near the U-shaped groove 5011, and the circular groove 5013 is not directly connected to the U-shaped groove 5011. The opening diameter of the circular groove 5013 is larger than the opening diameter of the elongated groove 5012, and the chain 3 can slide relative to it in the vertical direction within the circular groove 5013 of the limiting groove. The opening diameter of the elongated groove 5012 matches the thickness of the chain links of the chain 3.

[0059] The working process of the limiting locking plate 501 is as follows: After the chain 3 is placed in the chain hole 102, the U-shaped groove 5011 in the limiting locking plate 501 is inserted into the chain 3 and continues to move relative to the chain 3, confining the chain 3 in the circular groove 5013. The chain 3 can slide vertically in the circular groove 5013. Due to the limitation of the diameter of the elongated groove 5012, the chain 3 can be effectively prevented from coming out of the U-shaped groove 5011. When the chain 3 descends to the lowest point, the limiting locking plate 501 continues to move relative to the chain 3, confining the chain 3 in the elongated groove 5012. Since the opening diameter of the elongated groove 5012 matches the thickness of the chain links of the chain 3, it restricts the sliding and rotation of the chain 3 relative to the limiting locking plate 501, thus better preventing the chain 3 from coming out of the chain hole 102.

[0060] During the process of inserting the aforementioned limiting lock plate 501 into the chain 3, in order to better prevent the chain 3 from falling out of the chain hole 102, the opening groove and the U-shaped groove 5011 of the chain hole 102 are arranged on both sides of the chain hole 102 respectively.

[0061] More preferably, the chain limiting part 5 also includes a knurled collar 502, which is nested inside the chain hole 102 and has a lateral opening groove for the chain 3 to enter its interior. The chain 3 enters the internal through hole of the knurled collar 502 through the lateral opening groove.

[0062] By setting a knurled collar 502, which is fitted onto the outside of the chain 3, the inner diameter of the chain 3 is smaller than the inner diameter of the chain hole 102, thereby improving the positional accuracy of the chain 103 in the chain hole 102.

[0063] As an extension, the height of the knurled collar 502 is greater than the height of the chain hole 102, increasing the guiding distance of the chain 3 in the vertical direction of the knurled collar 502, thereby further improving the guiding accuracy of the chain 3 during its descent.

[0064] The working process of the limit lock plate 501 is as follows: the lock chain 3 is placed in the lock chain hole 102, and then the knurled collar 502 is placed in the lock chain hole 102, and the knurled collar 502 is sleeved on the outside of the lock chain 3.

[0065] More specifically, the knurled collar 502 includes a connected knurled section 5021 and a circular section 5022. The outer diameter of the circular section 5022 is smaller than the inner diameter of the chain hole 102. The circular section 5022 is nested inside the chain hole 102. During installation, the knurled collar 502 is inserted into the chain hole 102 from above, and the outer diameter of the knurled section 5021 is larger than the inner diameter of the chain hole 102, which can prevent it from falling off from below the chain hole 102. The top of the knurled section 5021 supports the limiting lock plate 501, thereby increasing the support area of ​​the limiting lock plate 501.

[0066] As a further preferred embodiment of any of the above embodiments, the lower mounting frame 4 is provided correspondingly to the upper hoisting frame 2.

[0067] The upper hoisting frame 2 is provided with multiple chain lifting rings 202 that are respectively connected to multiple chains 3. Preferably, the multiple chain lifting rings 202 are evenly distributed below the apex of the upper hoisting frame 2.

[0068] The lower mounting frame 4 is provided with multiple chain lower lifting rings 401 that are respectively connected to multiple chains 3. Preferably, the multiple chain lower lifting rings 401 are evenly distributed below the apex of the lower mounting frame 4.

[0069] More preferably, the upper lifting ring 202 and the lower lifting ring 401 of the chain are correspondingly arranged. During hoisting, the upper lifting ring 202 is located directly above the lower lifting ring 401, thereby reducing the angle between the chain 3 and the plumb bob.

[0070] For details, please refer to Figure 8 As shown, the upper hoisting frame 2 comprises a hollow rectangular frame consisting of four connecting rods. To increase the overall connection stability of the upper hoisting frame 2, reinforcing connecting rods are provided between adjacent connecting rods.

[0071] For more specific details, please refer to Figure 9 As shown, the lower mounting frame 4 includes a hollow rectangular frame consisting of four connecting rods. The fuel assembly passes vertically through the interior of the hollow rectangular frame, thereby entering the inspection area of ​​the inspection device.

[0072] This utility model also provides a device for four-sided inspection of fuel assemblies in nuclear power plants, including an inspection mechanism 6 and a hoisting mechanism according to any of the above embodiments, wherein the inspection mechanism is installed on the lower mounting frame 4.

[0073] To increase the movement space of the fuel assembly, as a preferred embodiment of the detection mechanism 6, refer to... Figure 10 , Figure 11 As shown, the detection mechanism includes four detection cameras 601 and lamps 604. The four detection cameras 601 are evenly distributed along the circumferential direction on the edge of the lower mounting frame 4, and the lamps 604 are evenly distributed at the vertices of the lower mounting frame 4. The light emitted by the lamps 604 is directed toward the interior of the lower mounting frame 4, thereby providing the light source required for detection by the detection cameras 601.

[0074] The specific installation method of the lamp 604 is as follows: the lamp support plate 602 is provided with a support rod connection hole 6022 and multiple base frame connection holes 6021. The multiple base frame connection holes 6021 are located on adjacent edges of the lamp support plate 602, and the support rod connection hole 6022 is located in the center of the lamp support plate 602. The lamp support plate 602 and two adjacent frames in the lower mounting frame 4 are fixedly connected through the base frame connection holes 6021. The lamp connecting support rod 603 is vertically arranged. The bottom end of the lamp connecting support rod 603 is fixedly installed in the support rod connection hole 6022, and the upper end of the lamp connecting support rod 603 is provided with a through lamp connecting hole 6031, which is used to connect with the lamp 604. It should be understood that the shape of the lamp connecting support rod 603 can be various. Preferably, the lamp connecting support rod 603 is a cylinder.

[0075] The initial assembly process of this four-sided inspection equipment is as follows:

[0076] Step 1: The detection mechanism 6 is installed on the lower mounting frame 4. One end of the chain 3 is connected to the lower mounting frame 4. Then, the chain 3 is placed into the chain hole 102 of the support base frame 1. Finally, the other end of the chain 3 is connected to the upper hoisting frame 2. The upper hoisting frame 2 is lifted by a crane.

[0077] Step 2: Fix the support frame 1 onto the transmission pool base;

[0078] Step 3: Then the crane drives the upper hoisting frame 2 downwards;

[0079] Step 4: As the descent reaches the preset depth, the upper hoisting frame 2 contacts the supporting base frame 1, and the descent stops;

[0080] Step 5: The chain limiting part 5 restricts the chain 3 in the chain hole 102 to prevent the chain 3 from coming out of the chain hole 102.

[0081] During initial assembly, the inspection equipment suspends the lower mounting frame 4 and its upper component inspection mechanism 6 from the supporting base frame 1 via chains 3. Because the inspection equipment is located underwater, there is resistance in the water, and its own mass is relatively large, resulting in good stability in the transfer pool and minimizing swaying, thus ensuring relatively accurate positioning within the transfer pool. Subsequent disassembly is unnecessary, reducing the frequency of crane use.

[0082] During use, the four-sided inspection device is located in the necessary path of the underwater transport of fuel assemblies. The corresponding inspection process is as follows: After the four-sided inspection device is assembled and lowered to the preset position in the transfer pool, the fuel assembly moves to the bottom of the inspection device, that is, directly below the detection mechanism 6. Then the fuel assembly passes through the detection mechanism 6 from bottom to top and continues to move upward, so that the detection mechanism 6 can inspect the appearance of the fuel assembly along its height direction. Finally, the fuel assembly moves horizontally and leaves the inspection device between the gaps of the two chains 3.

[0083] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A hoisting mechanism for four-sided inspection of fuel assemblies in a nuclear power plant, characterized in that, include The lower mounting frame (4) is used to mount the testing mechanism (6); The upper hoisting frame (2) is connected to the lower installation frame (4) by multiple chains (3) for hoisting the lower installation frame (4) and the detection mechanism (6), and the upper hoisting frame (2) is provided with a crane lifting ring (201) for connecting with a crane. And a support base frame (1), which is fixedly installed above the transmission pool and has chain holes (102) that correspond to multiple chains (3) and allow the chains (3) to slide through; and the support base frame (1) can be used to support the upper hoisting frame (2).

2. The hoisting mechanism for four-sided inspection of nuclear power plant fuel assemblies according to claim 1, characterized in that, The support frame (1) includes two parallel and spaced support rods (101). The support rods (101) straddle the transmission pool and are fixedly connected to the base of the transmission pool. The two support rods (101) are respectively provided with two chain holes (102). The upper hoisting frame (2) and the lower mounting frame (4) are connected by four chains (3).

3. The hoisting mechanism for four-sided inspection of nuclear power plant fuel assemblies according to claim 2, characterized in that, The two support rods (101) are fixedly connected at the same end by a support connecting rod (103) to form a U-shaped support base frame.

4. The hoisting mechanism for four-sided inspection of nuclear power plant fuel assemblies according to claim 3, characterized in that, The ends of the two support rods (101) that are connected to the support connecting rod (103) both protrude upward to form a connecting groove (1011), and the connecting groove (1011) is fixedly connected to the protrusion in the base of the transmission pool.

5. The hoisting mechanism for four-sided inspection of nuclear power plant fuel assemblies according to any one of claims 2-4, characterized in that, The opposite side of the chain hole (102) is provided with an opening groove that passes through it. The hoisting mechanism also includes a plurality of chain limiting parts (5) that are provided corresponding to the chain hole (102). The chain limiting parts (5) are used to restrict the chain (3) from coming out of the chain hole (102).

6. The hoisting mechanism for four-sided inspection of nuclear power plant fuel assemblies according to claim 5, characterized in that, The chain limiting part (5) includes a limiting locking piece (501), and the limiting locking piece (501) is provided with a limiting slot that is fitted onto the outside of the chain (3).

7. The hoisting mechanism for four-sided inspection of nuclear power plant fuel assemblies according to claim 6, characterized in that, The chain limiting part (5) also includes a knurled collar (502), which is fitted inside the chain hole (102) and has a lateral opening groove for the chain (3) to enter its interior.

8. The hoisting mechanism for four-sided inspection of nuclear power plant fuel assemblies according to claim 7, characterized in that, The knurled collar (502) includes a connected knurled section (5021) and a circular section (5022). The circular section (5022) is fitted inside the chain hole (102). The outer diameter of the knurled section (5021) is larger than the inner diameter of the chain hole (102). The top end of the knurled section (5021) supports the limiting lock piece (501).

9. The hoisting mechanism for four-sided inspection of fuel assemblies in a nuclear power plant according to any one of claims 1-4, characterized in that, The lower mounting frame (4) is set in correspondence with the upper hoisting frame (2).

10. A device for four-sided inspection of fuel assemblies in a nuclear power plant, characterized in that, It includes a testing mechanism (6) and a hoisting mechanism as described in any one of claims 1-9, wherein the testing mechanism (6) is mounted on the lower mounting frame (4).

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