Nuclear fuel rod fastener slitting mechanism

Abstract

The utility model provides a nuclear fuel rod fastener slitting mechanism, relates to reactor maintenance technical field, including connecting seat, casing, cutting piece and adjusting component, one end of casing is fixed on the connecting seat, and the other end is the insert end, the insert end is used for inserting in the fastener, the inside of casing is provided with the accommodation cavity, the cutting piece is fixed in the accommodation cavity, and the adjusting component is fixed in the accommodation cavity. A plurality of limiting openings are formed in the insertion end; the multiple cutting pieces are arranged in the containing cavity, each cutting piece comprises a cutting end, sawtooth-shaped protrusions are arranged at the cutting ends, and the cutting ends extend into the limiting openings in a one-to-one correspondence mode. According to the fuel assembly, the cutting piece and the adjusting assembly are arranged, so that after the fasteners fail, the disassembly operation of a single fastener can be realized, the situation that the fuel rod cannot be replaced after the fasteners fail is avoided, meanwhile, the fuel assembly does not need to be integrally replaced after the fasteners fail to a certain number, and the repair and maintenance cost can be reduced.

Description

Technical Field

[0001] This utility model relates to the field of reactor maintenance technology, and in particular to a nuclear fuel rod fastener cutting mechanism. Background Technology

[0002] Fuel assemblies are subject to various factors during operation, including water flow impact, vibration, and radiation, resulting in a certain rate of damage. Damage to fuel rods can lead to the leakage of fission products, increasing the primary circuit's radioactivity level and impacting the economics and safety of the nuclear power plant. Therefore, it is necessary to repair damaged fuel assemblies that have not reached burnup depth and replace the damaged fuel rods to ensure the safe and reliable operation of the reactor. For example, a fuel rod insertion and removal positioning device for fuel assembly repair, with notification number CN207718839U, uses four different mounting surfaces to position all fuel rods.

[0003] However, in actual operation, fuel rods need to be secured to fuel assemblies with fasteners. These fasteners are threaded to the fuel assemblies. However, repeated replacements of a certain part may cause the fasteners to fail and become impossible to remove, i.e., the threads are too tight to separate. In this case, the fuel rods can no longer be replaced at that installation location. Furthermore, since the fuel rods are placed in a boric acid water environment about 3 meters underwater, the space is confined, making it difficult to remove the fasteners in this situation. Currently, it is necessary to wait until the number of failed fasteners accumulates to a certain extent before replacing the entire fuel assembly. This approach will affect the reactor's reaction rate as the fasteners gradually fail, and the overall cost of replacing the entire fuel assembly is even higher. Utility Model Content

[0004] In view of this, the present invention proposes a nuclear fuel rod fastener cutting mechanism. By setting a cutting component and an adjustment component, during operation, the connecting seat is placed directly outside the fastener to be removed, and the sleeve is inserted into the fastener. The adjustment component drives the cutting component to move up and down. During the movement, the adjustment component causes the cutting component to change the size of the protrusion limit opening, thereby changing the feed depth of the cutting component in the fastener until the connection stress between the fastener and the fuel assembly is eliminated, and then the fastener is removed. This method can realize the removal of individual fasteners after fastener failure, avoiding the inability to replace fuel rods after fastener failure. At the same time, it eliminates the need to replace the entire fuel assembly after a certain number of fasteners fail, thereby reducing maintenance costs.

[0005] The technical solution of this utility model is achieved as follows: This utility model provides a nuclear fuel rod fastener cutting mechanism, including a connecting seat, a sleeve, a cutting component, and an adjustment assembly, wherein...

[0006] One end of the sleeve is fixed to the connector, and the other end is the insertion end. The insertion end is used to insert into the fastener. The sleeve has an accommodating cavity inside, and the insertion end has multiple limiting ports.

[0007] There are multiple cutting components, all of which are set in the accommodating cavity. Each cutting component includes a cutting end with a serrated protrusion. Each cutting end extends into a corresponding limiting port, and the serrated protrusion extends to the outside of the insertion end through the limiting port. The cutting component can move along the length of the sleeve to cut the fastener through reciprocating motion.

[0008] The adjustment assembly is mounted on the connecting seat, and the ends of each cutting component of the adjustment assembly are connected by a transmission. The adjustment assembly is used to drive the cutting end to extend into and out of the limiting port.

[0009] Based on the above technical solutions, preferably, the adjustment component includes multiple movable blocks, the number of which is the same as the number of cutting parts. The ends of the cutting parts are fixed on the movable blocks, and all the movable blocks are disposed in the connecting seat.

[0010] More preferably, each of the cutting components and the movable block is distributed in a ring around the axis of the sleeve.

[0011] More preferably, the adjustment assembly further includes an adjustment seat, which is drivenly connected to each movable block to move each movable block along the radial direction of the sleeve.

[0012] More preferably, the adjusting seat has a guide groove, the movable block extends into the guide groove, and is slidably connected to the adjusting seat through the guide groove.

[0013] More preferably, the adjusting seat is provided with an Archimedean spiral structure, and all the movable blocks are engaged with the Archimedean spiral structure so that the adjusting seat and each movable block are connected by transmission.

[0014] Based on the above technical solutions, preferably, the insertion end is provided with a conical surface.

[0015] Based on the above technical solutions, preferably, the number of cutting parts is three, and they are distributed around the axis of the sleeve at a 60-degree angle.

[0016] Based on the above technical solutions, preferably, it also includes a transmission rod, the end of which is connected to an adjustment assembly, and the transmission rod is used to drive the cutting part to reciprocate through the adjustment assembly.

[0017] The nuclear fuel rod fastener cutting mechanism of this invention has the following advantages over the prior art:

[0018] (1) By setting up a cutting component and an adjustment component, during operation, the connecting seat is placed directly outside the fastener to be removed, and the sleeve is inserted into the fastener. The adjustment component drives the cutting component to move up and down. During the movement, the adjustment component drives the cutting component to change the size of the protrusion limit port, thereby changing the feed depth of the cutting component in the fastener until the connection stress between the fastener and the fuel assembly is eliminated, and then the fastener is removed. In this way, the removal of a single fastener can be achieved after the fastener fails, avoiding the inability to replace the fuel rod after the fastener fails. At the same time, it is not necessary to replace the entire fuel assembly after a certain number of fasteners fail, which can reduce maintenance costs.

[0019] (2) An Archimedean spiral structure is set on the adjusting seat, and all the moving blocks are matched with the Archimedean spiral structure so that the adjusting seat and each moving block are connected by transmission. The Archimedean spiral structure is set to push or pull all the moving blocks synchronously to achieve synchronous feeding action. This structure has good stability and synchronization accuracy. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a perspective view of the nuclear fuel rod fastener cutting mechanism of this utility model;

[0022] Figure 2 This is a partial perspective view of the nuclear fuel rod fastener cutting mechanism of this utility model;

[0023] Figure 3 This is a schematic diagram showing the connection between the cutting component and the movable block of the nuclear fuel rod fastener cutting mechanism of this utility model.

[0024] Figure 4 This is a schematic diagram illustrating the fastener cutting operation of the nuclear fuel rod fastener cutting mechanism of this utility model. Detailed Implementation

[0025] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0026] like Figure 1-4 As shown, the nuclear fuel rod fastener cutting mechanism of this utility model includes a connecting seat 1, a sleeve 2, a cutting component 3, and an adjustment assembly 4.

[0027] When fastener cutting is being performed, connector 1 needs to be fixed relative to the fuel assembly, and it can be connected to the rack on the shore.

[0028] One end of the sleeve 2 is fixed to the connecting seat 1, and the other end is the insertion end 21. The insertion end 21 is used to insert into the fastener. The sleeve 2 has a receiving cavity inside, and the insertion end 21 has multiple limiting ports. Both the sleeve 2 and the connecting seat 1 are designed to compensate for the distance from the shore to the fuel assembly, so that the insertion end 21 of the sleeve 2 can be inserted into the fastener of the fuel assembly. The sleeve 2 is hollow inside and is designed as a receiving cavity. Its shape is adapted to the size of the cutting part 3 for installation.

[0029] Multiple cutting components 3 are provided, all housed within the receiving cavity. Each cutting component 3 includes a cutting end 31 with serrated protrusions. Each cutting end 31 extends into a corresponding limiting port, and the serrated protrusions extend to the outside of the insertion end 21 through the limiting port. The cutting component 3 can move along the length of the sleeve 2 to cut the fastener through reciprocating motion. In some embodiments, the outer diameter of the insertion end 21 of the sleeve 2 is generally smaller than that of the sleeve 2, allowing the insertion end 21 to... After the fastener is inserted, the sleeve 2 can no longer be inserted. At the same time, the cutting component 3 can extend out of the insertion end 21 of the sleeve 2 through the limiting port. Specifically, the cutting component 3 can be a saw blade structure, which is arranged in a straight line and the saw teeth are all facing outwards from the limiting port. When cutting the fastener, the saw blade is pulled back and forth by the saw teeth to cut the fastener. The number of cutting components 3 can be selected according to the actual situation. In order to facilitate the removal operation after the fastener is cut, it is preferable to have three or more cutting components 3.

[0030] In addition, the accommodating cavity on the sleeve 2 can limit the movement range of the cutting piece 3, preventing damage to the fuel assembly due to excessive feed during the cutting process.

[0031] The adjustment component 4 is mounted on the connecting seat 1. The ends of each cutting piece 3 of the adjustment component 4 are connected by a transmission. The adjustment component 4 is used to drive the cutting end 31 to extend into and out of the limiting port.

[0032] Considering that the cutting part 3 needs to reciprocate and needs to be continuously fed during the cutting operation, the adjustment component 4 can transmit the force of the vertical reciprocating motion to the cutting part 3, so that the cutting part 3 can continuously reciprocate up and down in the accommodating cavity. At the same time, the adjustment component 4 can continuously push the cutting part 3 to feed during the movement, so as to improve the cutting efficiency of fasteners.

[0033] This embodiment, by setting up a cutting component 3 and an adjusting component 4, allows for operation where the connecting seat 1 is placed outside the fastener to be removed, and the sleeve 2 is inserted into the fastener. The adjusting component 4 drives the cutting component 3 to move up and down. During the movement, the adjusting component 4 causes the cutting component 3 to change the size of the protrusion limit opening, thereby changing the feed depth of the cutting component in the fastener until the connection stress between the fastener and the fuel assembly is eliminated, and then the fastener is removed. This method allows for the removal of individual fasteners after fastener failure, avoiding the inability to replace fuel rods after fastener failure. At the same time, it eliminates the need to replace the entire fuel assembly after a certain number of fasteners fail, thus reducing maintenance costs.

[0034] In some embodiments, the adjustment component 4 includes multiple movable blocks 41, the number of which is the same as the number of cutting pieces 3. The ends of the cutting pieces 3 are fixed to the movable blocks 41, and all movable blocks 41 are disposed within the connecting seat 1.

[0035] The adjustment component 4 can drive the cutting part 3 to move or reciprocate through the set movable block 41. The movable block 41 can be directly welded to the cutting part 3, or the cutting part 3 can be fixed to the movable block 41 by bolts, thereby connecting the cutting part 3 and the adjustment component.

[0036] In a specific embodiment, each of the cutting elements 3 and the movable block 41 are arranged in a ring around the axis of the sleeve 2. This arrangement ensures that each cutting element 3 has a synchronous cutting feed depth in the fastener, thereby improving cutting efficiency and ensuring maximum stress release of the fastener when cutting to the same depth.

[0037] To achieve synchronous feed adjustment of each cutting piece 3, in some embodiments, the adjustment assembly 4 further includes an adjustment seat 42, which is connected to each movable block 41 in a transmission manner so that each movable block 41 moves along the radius of the sleeve 2. The adjustment seat 42 is used to synchronously adjust each movable block 41. It should be noted that this synchronous adjustment is based on the axis of the sleeve 2. A circle is drawn with the axis of the sleeve 2 as the center, and each movable block 41 moves on the radius of the circle, thereby achieving synchronous feed adjustment of each cutting piece 3.

[0038] To guide the movable block 41, in some embodiments, the adjusting seat 42 is provided with a guide groove 421. The movable block 41 extends into the guide groove 421 and is slidably connected to the adjusting seat 42 through the guide groove 421. Specifically, the number of guide grooves 421 is the same as that of the movable block 41, and the arrangement is consistent. The guide grooves 421 correspond one-to-one with the movable blocks 41. The cross-section of the guide groove 421 is T-shaped. The part of the movable block 41 extending into the guide groove 421 is adapted to it, thereby achieving stable guiding sliding. In addition, during the sliding process of the movable block 41, the connecting seat 1 limits it to prevent the movable block 41 from leaving the guide groove 421. At the same time, a synchronously cooperating limiting structure can also be provided on the movable block 41 and the guide groove 421 to improve the stability during sliding.

[0039] In a specific embodiment, the adjusting seat 42 is provided with a rotatable disc-shaped component, on which an Archimedean spiral structure is provided. The disc-shaped component can rotate relative to the adjusting seat 42 as a whole, and drive the Archimedean spiral structure to rotate. All the movable blocks 41 cooperate with the Archimedean spiral structure so that the disc-shaped component inside the adjusting seat 42 and each movable block 41 are connected by transmission. The Archimedean spiral structure is used to push or pull all the movable blocks 41 synchronously to achieve their synchronous feeding action. The specific structure can be referred to as a three-jaw chuck. This setting has good stability and synchronization accuracy.

[0040] In some embodiments, the insertion end 21 is provided with a conical surface 211, through which the insertion end 21 can be inserted into the fastener. This arrangement makes it easier to insert and align, and is more convenient and reliable for cutting operations in boric acid at a depth of three meters, thereby improving work efficiency.

[0041] In some embodiments, taking three cutting pieces 3 as an example, the three cutting pieces 3 are distributed around the axis of the sleeve 2 at a 60-degree angle, so that the fastener is cut simultaneously from three directions during the cutting process. After cutting, the fastener is divided into three parts, which release the connection stress between the fastener and the fuel assembly through the three cutting gaps. Then the cut fastener can be removed.

[0042] In order to further connect external transmission mechanisms or devices, in some embodiments, a transmission rod 5 is also provided. The end of the transmission rod 5 is connected to the adjustment component 4. The transmission rod 5 is used to drive the cutting part 3 to reciprocate through the adjustment component 4. The rotation and reciprocating motion of other devices or mechanisms are transmitted to the adjustment component 4 through the transmission rod 5, and then transmitted to the cutting part 3 by the adjustment component 4, thereby completing the cutting operation.

[0043] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A nuclear fuel rod fastener slitting mechanism characterized by: Includes a connector (1), a sleeve (2), a cutting component (3), and an adjustment assembly (4), wherein, One end of the sleeve (2) is fixed on the connecting seat (1), and the other end is the insertion end (21). The insertion end (21) is used to insert into the fastener. The sleeve (2) has a receiving cavity inside, and the insertion end (21) has multiple limiting ports. There are multiple cutting parts (3), all of which are set in the accommodating cavity. Each cutting part (3) includes a cutting end (31) with a serrated protrusion. Each cutting end (31) extends into each limiting port in a corresponding manner, and the serrated protrusion extends to the outside of the insertion end (21) through the limiting port. The cutting part (3) can move along the length direction of the sleeve (2) to cut the fastener through reciprocating motion. The adjustment component (4) is set on the connecting seat (1). The ends of each cutting piece (3) of the adjustment component (4) are connected by transmission. The adjustment component (4) is used to drive the cutting end (31) to extend into and out of the limiting port.

2. The nuclear fuel rod fastener slitting mechanism of claim 1, wherein: The adjustment component (4) includes multiple movable blocks (41), the number of which is the same as the number of cutting pieces (3). The ends of the cutting pieces (3) are fixed on the movable blocks (41), and the movable blocks (41) are all arranged in the connecting seat (1).

3. The nuclear fuel rod fastener slitting mechanism of claim 2, wherein: Each of the cutting components (3) and the movable block (41) is distributed in a ring around the axis of the sleeve (2).

4. The nuclear fuel rod fastener slitting mechanism of claim 3, wherein: The adjustment assembly (4) further includes an adjustment seat (42), which is connected to each movable block (41) in a transmission manner so that each movable block (41) moves along the radial direction of the sleeve (2).

5. The nuclear fuel rod fastener slitting mechanism of claim 4, wherein: The adjusting seat (42) is provided with a guide groove (421), and the movable block (41) extends into the guide groove (421) and is slidably connected to the adjusting seat (42) through the guide groove (421).

6. The nuclear fuel rod fastener slitting mechanism of claim 4, wherein: The adjusting seat (42) is provided with an Archimedean spiral structure, and all the movable blocks (41) are engaged with the Archimedean spiral structure so that the adjusting seat (42) and each movable block (41) are connected by transmission.

7. The nuclear fuel rod fastener slitting mechanism of claim 1, wherein: The insertion end (21) is provided with a conical surface (211).

8. The nuclear fuel rod fastener slitting mechanism of claim 1, wherein: The number of the cutting parts (3) is three, and they are distributed around the axis of the sleeve (2) at a 60-degree angle.

9. The nuclear fuel rod fastener slitting mechanism of claim 1, wherein: It also includes a transmission rod (5), the end of which is connected to the adjustment assembly (4). The transmission rod (5) is used to drive the cutting piece (3) to reciprocate through the adjustment assembly (4).

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