Control rod assembly

Abstract

The invention relates to a control rod assembly which comprises a plurality of control rods and a control rod guide cylinder assembly, the control rod guide cylinder assembly is provided with a plurality of guide channels, each control rod is inserted into the corresponding guide channel, the control rod assembly further comprises a repelling structure arranged between each pair of guide channels and the control rod, and the repelling structures are used for generating force for preventing the control rods from approaching the circumferential side walls of the guide channels. The repelling structure can hinder interaction between the control rod and the circumferential side wall of the guide channel, and abrasion of the outer surface of the control rod is relieved.

Description

Technical Field

[0001] The present invention relates to the field of reactor cores, and in particular to a control rod assembly. Background Art

[0002] The control rod assembly is a tool for quickly controlling reactivity. It is used to regulate reactor power during normal operation and quickly introduce negative reactivity under accident conditions to shut down the reactor urgently, thereby ensuring nuclear safety.

[0003] The control rod assembly may include a plurality of control rods and a control rod guide tube assembly for guiding each control rod to a guide tube of a corresponding fuel assembly. The control rod guide tube assembly is provided with a plurality of guide channels, and each control rod may be inserted into a corresponding guide channel.

[0004] However, the control rods may be damaged in appearance due to lateral shaking and abrasion of the circumferential side walls of the guide channel, posing a risk of control rod failure. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the control rod is prone to abrasion with the circumferential side wall of the guide channel. Based on this, a control rod assembly is provided.

[0006] The technical solution adopted by the present invention to solve the technical problem is: construct a control rod assembly, including a plurality of control rods and a control rod guide cylinder assembly; the control rod guide cylinder assembly is provided with a plurality of guide channels, each of the control rods is inserted into the corresponding guide channel,

[0007] The control rod assembly further includes a repelling structure disposed between each group of the guide channels and the control rods, the repelling structure being configured to generate a force preventing the control rods from approaching the circumferential side walls of the guide channels.

[0008] In some embodiments, the repulsion structure includes a first magnetic component installed on the control rod, and a second magnetic component installed on the side wall of the guide channel; the first magnetic component and the second magnetic component are arranged to repel each other.

[0009] In some embodiments, the control rod includes a cylindrical cladding and an absorber core block arranged in the cladding; the first magnetic assembly includes at least three first magnetic parts in the shape of long strips, which are respectively embedded between the cladding and the absorber core block and are evenly spaced in the circumferential direction of the control rod; the length direction of each first magnetic part is parallel to the axial direction of the absorber core block.

[0010] In some embodiments, each of the guide channels is defined by a plurality of guide structures; the plurality of guide structures include guide cylinders and a plurality of guide clamping holes arranged on the same longitudinal straight line;

[0011] The second magnetic component includes a plurality of second magnetic parts embedded in each of the guide structures; all of the first magnetic parts are uniformly configured to interact with the corresponding second magnetic parts, and the circumferential length of each of the second magnetic parts is greater than the overall circumferential length of the first magnetic part that interacts with the second magnetic part.

[0012] In some embodiments, the control rod assembly further comprises a support structure, the plurality of control rods are mounted on the support structure; the guide structure is provided with an escape opening for a portion of the support structure to pass through;

[0013] The plurality of second magnetic parts are distributed on both sides of the symmetry axis in a mirror-symmetrical manner with the shortest straight line between the center point of the avoidance opening and the center axis of the guide structure as the symmetry axis; and each of the second magnetic parts maintains a distance from the avoidance opening in the circumferential direction.

[0014] In some embodiments, the first magnetic assembly includes four first magnetic parts, each of which is a long magnetic strip, and its length is equivalent to the length of the absorber core block;

[0015] Each of the guide structures is provided with two symmetrically arranged second magnetic parts, each of which is an arc-shaped magnetic strip; on the circumference of the guide structure, the central angle corresponding to the second magnetic part is between 100° and 110°;

[0016] The four first magnetic parts are oriented toward the surfaces of the two second magnetic parts in pairs.

[0017] In some embodiments, a mounting groove for inserting a corresponding magnetic part is provided on the circumferential outer wall of the absorbent core block and / or the circumferential side wall of the guide structure; the corresponding magnetic part is the first magnetic part or the second magnetic part;

[0018] A limiting structure is provided between the mounting slot and the corresponding magnetic portion to limit the corresponding magnetic portion from being separated from the mounting slot;

[0019] Wherein, the mounting groove is a trapezoidal slot, and at least one groove side wall of the mounting groove and the groove bottom wall of the mounting groove form an acute angle area as the limiting structure to clamp a part of the structure corresponding to the magnetic part;

[0020] Alternatively, the limiting structure includes a protruding portion provided at one of the mounting slot and the corresponding magnetic portion, and a recessed portion provided at the other of the mounting slot and the corresponding magnetic portion; the protruding portion is inserted into the recessed portion.

[0021] In some embodiments, the first magnetic assembly includes at least three first magnetic parts arranged in the circumferential direction of the control rod;

[0022] Each of the guide channels is defined by a plurality of guide structures; the plurality of guide structures include guide cylinders and a plurality of guide clamping holes arranged on the same longitudinal straight line; the second magnetic assembly includes a plurality of second magnetic parts embedded in the circumference of each of the guide structures;

[0023] All the first magnetic parts are evenly arranged to interact with the corresponding second magnetic parts, and the thickness of the first magnetic parts and / or the second magnetic parts is between 0.8 mm and 1.5 mm.

[0024] In some embodiments, a lubricating coating is provided on at least one of the circumferential side walls of the guide channel and the circumferential side walls of the control rod.

[0025] In some embodiments, the lubricating coating is a high-temperature resistant solid self-lubricating coating; the high-temperature resistant solid self-lubricating coating includes one of a metal-based high-temperature self-lubricating coating, a metal ternary oxide-based self-lubricating coating and a ceramic-based high-temperature self-lubricating coating.

[0026] The implementation of the present invention has the following beneficial effects: the present invention sets a repulsive structure between each pair of guide channels and control rods to hinder the interaction between the control rods and the circumferential side walls of the guide channels, thereby reducing the abrasion of the outer surface of the control rods, thereby improving the anti-abrasion performance of the control rod assembly in disguised form and extending the service life of the control rods. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0028] Figure 1 is a horizontal cross-sectional view of a portion of control rods of a control rod assembly in some embodiments of the present invention, in which control rods are inserted into a guide channel;

[0029] Figure 2 is a cross-sectional view of a control rod in a horizontal direction in some embodiments;

[0030] Figure 3 is a schematic diagram of clamping the first magnetic part through a trapezoidal clamping groove in some embodiments of the present invention;

[0031] Figure 4 It is a cross-sectional view in the horizontal direction of part of the guide mechanism in some embodiments of the present invention.

[0032] Reference numerals:

[0033] Control rod 1; cladding 11; absorber core block 12; guide channel 2; guide structure 21; avoidance port 22; avoidance channel 3; repulsion structure 4; first magnetic component 41; first magnetic part 411; second magnetic component 42; second magnetic part 421 mounting groove 43; restriction structure 44; lubricating coating 5. DETAILED DESCRIPTION

[0034] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings, are constructed and operated in a specific direction, and are only for the convenience of describing the present technical solution, rather than indicating that the device or element referred to must have a specific direction, and therefore cannot be understood as a limitation to the present invention.

[0035] It should also be noted that, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed", "set" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intermediate elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third", etc. can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0036] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0037] Regarding the problem that the control rod 1 is prone to abrasion with the circumferential side wall of the guide channel 2, please refer to Figure 1 The present invention constructs a control rod assembly, which mainly includes a plurality of control rods 1 and a control rod guide cylinder assembly; the control rod guide cylinder assembly is provided with a plurality of guide channels 2, and each control rod 1 can be inserted into a corresponding guide channel 2. The control rod assembly also includes a repulsion structure 4 arranged between each pair of guide channels 2 and the control rod 1, and the repulsion structure 4 is used to generate a force to prevent the control rod 1 from approaching the circumferential side wall of the guide channel 2, so as to prevent the control rod 1 from contacting the circumferential side wall of the guide channel 2.

[0038] Understandably, reference can be made to Figure 2 The control rod 1 includes a cylindrical cladding 11 and an absorber core block 12 disposed in the cladding 11. The micromotion (small amplitude reciprocating motion) abrasion caused by the vibration of the control rod 1 under the action of fluid force, and the sliding abrasion during the up and down stepping of the control rod 1, will cause the local thickness of the cladding 11 of the control rod 1 to be thinned, and the mechanical strength to decrease; when fatigue intensifies, it will affect the structural integrity of the cladding 11, resulting in failure of the control rod 1. In severe cases, abrasion will penetrate the wall of the cladding 11, and the activation products of the absorber core block 12 in the control rod 1 may enter the coolant of the primary circuit. Therefore, the failure problem caused by the abrasion of the control rod 1 has a bad impact on the life of the control rod 1 and the safety of the reactor. In the face of the above problems, the anti-abrasion performance of the control rod 1 was improved by increasing the hardness of the cladding 11 of the control rod 1 in the past, and no consideration has been given to directly reducing the force of friction on the contact.

[0039] The present invention sets a repulsive structure 4 between each pair of guide channels 2 and the control rods 1, thereby preventing the interaction between the control rods 1 and the circumferential side walls of the guide channels 2 without affecting the normal functions of the control rod assembly, reducing the fretting and sliding abrasion of the outer surface of the cladding 11 of the control rod 1, thereby improving the anti-wear performance of the control rod assembly in disguised form, extending the service life of the control rods 1, and having important significance for improving the safety and economy of the reactor operation.

[0040] Secondly, if Figure 2 or Figure 4 As shown, a lubricating coating 5 may be provided on at least one of the circumferential side walls of the guide channel 2 and the circumferential side walls of the control rod 1 in the circumferential direction, so as to reduce the abrasion damage between the control rod 1 and the guide channel 2 .

[0041] The repelling structure 4 will be described below.

[0042] In some embodiments, Figure 1As shown, the repulsive structure 4 may include a first magnetic component 41 installed in the circumferential direction of the control rod 1, and a second magnetic component 42 installed on the circumferential side wall of the guide channel 2; the first magnetic component 41 and the second magnetic component 42 are arranged to repel each other. The two can generate magnetic forces that repel each other when the control rod 1 moves radially, so as to prevent abrasion between the control rod 1 and the circumferential side wall of the guide channel 2. The first magnetic component 41 and the second magnetic component 42 may be permanent magnets.

[0043] In some other embodiments (not shown in the figure), the repelling structure 4 may include an outlet provided on the circumferential side wall of at least one of the control rod 1 and the guide channel 2, and a gas supply device connected to the outlet for delivering gas to the outlet. It can be understood that gas can be output at the outlet to generate thrust to prevent abrasion between the control rod 1 and the circumferential side wall of the guide channel 2. Secondly, since the gas push needs to be provided with an outlet, the structural strength of the control rod 1 and the guide channel 2 will be weakened, so the magnetic push method is more preferred, which can also protect the structural strength of the control rod 1 and the guide channel 2.

[0044] The following focuses on the specific structure of the magnetic component.

[0045] See also Figure 2 The first magnetic assembly 41 may include a plurality of first magnetic parts 411 evenly spaced in the circumferential direction of the control rod 1. At least three first magnetic parts 411 are provided, because it is necessary to avoid the supporting structure of the control rod 1. If one or two first magnetic parts 411 are provided, it is impossible to take into account the movement of the control rod 1 in multiple directions.

[0046] Each first magnetic portion 411 is a long magnetic strip, and its length direction is parallel to the axial direction of the control rod 1. The length of the magnetic strip may account for 80%-100% of the total length of the control rod 1, because if the length of the magnetic strip is too short, it is difficult to play a blocking role, and may also cause the control rod 1 to deviate additionally.

[0047] In some other embodiments, the first magnetic part 411 may also be composed of a plurality of small magnets continuously spliced ​​together. Alternatively, the first magnetic part 411 may also be composed of a plurality of small magnets arranged at intervals; the positions of the plurality of small magnets arranged at intervals correspond to the positions of the guide card and the guide cylinder of the control rod guide cylinder assembly. The structural composition of these first magnetic parts 411 should also fall within the protection scope of the present invention.

[0048] Secondly, if Figure 2As shown, the first magnetic component 41 can be arranged between the cladding 11 of the control rod 1 and the absorber core block 12. In this way, the cladding 11 can protect the first magnetic component 41, and prevent the first magnetic component 41 from being worn and consumed when the control rod 1 and the guide cylinder are eroded, thereby causing an unbalanced magnetic field force. Of course, the first magnetic component 41 can also be directly arranged on the outer circumference of the control rod 1, and this arrangement should also be included in the protection scope of the present invention.

[0049] The following description will be made by taking the embodiment in which the first magnetic part 411 is a long strip of magnetic strip as an example. The first magnetic part 411 can be embedded in the absorbent core block 12. For example, Figure 2 As shown, a mounting groove 43 may be provided on the absorbent core block 12, and then the first magnetic part 411 may be embedded in the mounting groove 43. The mounting groove 43 may be formed by radially concave along the outer surface of the circumferential direction of the absorbent core block 12, and may be provided with a notch located at the outer circumferential surface of the absorbent core block 12. One side surface of the first magnetic part 411 may be flush with the outer circumferential surface of the absorbent core block 12, so as to avoid the first magnetic part 411 being too far away from the circumferential side wall of the guide channel 2, resulting in poor blocking effect.

[0050] The shape of the mounting groove 43 is adapted to the first magnetic part 411, that is, the mounting groove 43 is longitudinally elongated, and its length direction is parallel to the axial direction of the control rod 1. The mounting groove 43 can be a through groove, at least one of the two ends of which is open, and the first magnetic part 411 can be inserted into the mounting groove 43 from one end of the mounting groove 43. Preferably, since the absorber core block 12 is an alloy rod, considering the feasibility of the manufacturing process, it is more appropriate to design a mounting groove 43 that runs through the entire length on the outer surface of the absorber core block 12. The first magnetic part 411 can be inserted into the mounting groove 43 from one end of the absorber core block 12.

[0051] For reference Figure 3 A limiting structure 44 may be further provided between the mounting slot 43 and the first magnetic portion 411 to prevent the first magnetic portion 411 from being easily separated from the mounting slot 43 .

[0052] In some embodiments, Figure 3 As shown, the mounting groove 43 may be a trapezoidal slot, the lower bottom side of the mounting groove 43 is arranged closer to the central axis of the absorbent core block 12 than the upper bottom side thereof, and an acute angle region is formed between at least one groove side wall (the wall on the waist side) of the mounting groove 43 and the groove bottom wall (the wall on the lower bottom side) of the mounting groove 43. A portion of the structure of the first magnetic part 411 may be arranged in the acute angle region. In other words, the acute angle region of the mounting groove 43, as a limiting structure 44, may clamp a portion of the structure of the first magnetic part 411, so that the first magnetic part 411 cannot be detached from the mounting groove 43.

[0053] For example, the mounting groove 43 may be an isosceles trapezoidal slot, and an acute angle is formed between the two groove side walls and the groove bottom wall of the mounting groove 43. The shape of the first magnetic portion 411 matches the shape of the mounting groove 43, and the first magnetic portion 411 is provided with two side surfaces corresponding to the two groove side walls, and the two side surfaces respectively form complementary surfaces with the two groove side walls of the mounting groove 43.

[0054] Optionally, the acute angle formed between the groove side wall and the groove bottom wall of the mounting groove 43 may be between 15° and 25°, preferably 20°, to ensure that the first magnetic part 411 can be tightly combined with the absorbent core block 12 .

[0055] In some other embodiments (not shown in the figure), the limiting structure 44 may be a mortise and tenon structure provided between the mounting slot 43 and the first magnetic part 411. The limiting structure 44 may include a protruding portion provided at one of the mounting slot 43 and the first magnetic part 411, and a groove portion provided at the other of the mounting slot 43 and the first magnetic part 411; when the first magnetic part 411 is installed in the mounting slot 43, the protruding portion may be inserted into the groove portion to prevent the first magnetic part 411 from being separated from the mounting slot 43.

[0056] For example, a groove portion is respectively provided on the two groove side walls of the installation groove 43, and the groove portion is a long groove, which is formed on the installation groove 43 along the length direction of the installation groove 43; at the same time, the first magnetic portion 411 is provided with two side surfaces corresponding to the two groove side walls, and the two side surfaces are respectively provided with a protrusion, which is a long strip structure, and is combined with the first magnetic component 41 along the length direction of the first magnetic portion 411. In this embodiment, the groove side wall of the installation groove 43 can be perpendicular to the tangent of the point where it is connected to the edge of the absorbent core block 12, and the side surface of the first magnetic portion 411 can be arranged parallel to the groove side wall of the installation groove 43.

[0057] It can be understood that the above two embodiments both rely on pure mechanical action to enable the first magnetic part 411 to be firmly combined with the absorbent core block 12, thereby avoiding redundant effects on the material of the absorbent core block 12 in the processing technology. Moreover, compared with the mortise and tenon structure, the design and processing of the trapezoidal slot is easier and more convenient, and there is no risk of the protrusion breaking. In addition, it can also be explained that compared with the first magnetic part 411 composed of small magnets, since the contact area between the long strip of magnetic strips and the mounting groove 43 is larger and the friction force is also greater, the first magnetic part 411 can be more securely embedded in the absorbent core block 12.

[0058] Then, before describing the second magnetic assembly 42, the specific structure of the control rod guide tube assembly will be introduced here.

[0059] The control rod guide cylinder assembly includes several layers of guide cards arranged longitudinally, and several guide cylinders arranged between the guide cards and the fuel assembly. Each layer of guide cards is provided with several guide card holes, and the guide cylinders correspond to the guide card holes one by one; the end of any control rod 1 will pass through the corresponding guide card holes of each layer in turn, and then pass through a corresponding guide cylinder to reach the fuel assembly. In other words, each guide channel 2 is defined by a plurality of guide structures 21, and the guide structure 21 mentioned here can refer to a guide card hole or a guide cylinder; in other words, each guide channel 2 is defined by a plurality of guide structures 21; the plurality of guide structures 21 include guide cylinders and a plurality of guide card holes arranged on the same longitudinal straight line; and the circumferential side wall of the guide channel 2 includes the hole wall of the guide card hole and the cylinder wall of the guide cylinder.

[0060] Therefore, the second magnetic assembly 42 may include a plurality of second magnetic parts 421 embedded in each of the guide structures 21. In other words, a plurality of second magnetic parts 421 may be respectively disposed on the guide clamping hole and the guide cylinder.

[0061] For reference Figure 4 , which shows a horizontal cross-sectional view of a plurality of second magnetic parts 421 embedded in the guide structure 21. It can be explained here that since the horizontal cross-sectional view of the guide cylinder is similar to that of the guide clamping hole, the schematic diagram of the second magnetic part 421 embedded in the guide cylinder / guide clamping hole can refer to Figure 4 .

[0062] like Figure 4 As shown, in any guide structure 21, the second magnetic part 421 can be an arc-shaped structure, embedded in the circumferential side wall of the guide structure 21. For example, the second magnetic part 421 can be embedded in the guide structure 21 by opening a mounting groove 43 on the circumferential inner wall of the guide structure 21. The specific embedding method can refer to the above description of the embedding of the first magnetic part 411 in the mounting groove 43, which will not be repeated here.

[0063] Among them, a single second magnetic portion 421 can interact with a single first magnetic portion 411 in a one-to-one correspondence (not shown in this embodiment). That is, the number of second magnetic portions 421 and the circumferential position of the guide structure 21 can correspond to the first magnetic portion 411. The length of the second magnetic portion 421 in the circumferential direction can be equivalent to the length of the first magnetic portion in the circumferential direction; at the same time, the number of second magnetic portions 421 is equal to the number of first magnetic portions 411, and they are evenly spaced along the circumference of the guide structure 21, and correspond to the position of the first magnetic portion 411 in the circumferential direction.

[0064] Alternatively, if Figure 4As shown, a single second magnetic part 421 may also interact with a plurality of first magnetic parts 411. That is, a plurality of first magnetic parts 411 are arranged relative to a second magnetic part 421; the length of the second magnetic part 421 in the circumferential direction is equivalent to the overall length of the plurality of first magnetic parts 411 interacting with the second magnetic part 421 in the circumferential direction.

[0065] For example, in Figure 4 In the illustrated embodiment, two first magnetic portions 411 are provided to cooperate with the second magnetic portion 421 located on the upper side. Then, the overall circumferential length of the first magnetic portion 411 that cooperates with the second magnetic portion 421 is the circumferential width of the two first magnetic portions 411 plus the circumferential distance between the two first magnetic portions 411.

[0066] Regardless of whether a single second magnetic part 421 cooperates with one or more first magnetic parts 411, it is necessary to ensure that all first magnetic parts 411 can be evenly configured to interact with the corresponding second magnetic parts 421 to ensure that the force is balanced. Secondly, it is preferred to design the second magnetic part 421 to have a circumferential length greater than the overall circumferential length of the first magnetic part 411 interacting with the second magnetic part 421; the purpose of such a setting is to retain a certain margin to ensure that the second magnetic part 421 can cover the first magnetic component 41 interacting with the second magnetic part 421 in the circumferential direction, thereby avoiding misalignment between the second magnetic part 421 and the first magnetic part 411, resulting in a biased repulsive force.

[0067] Each second magnetic portion 421 may also be an integrated magnetic strip, or may be formed by splicing a plurality of small magnets, which is not limited here. The axial length of the second magnetic portion 421 may be equal to the axial length of the guide structure 21 .

[0068] In addition, since the control rod assembly also includes a support structure, a plurality of control rods 1 can be mounted on the support structure. In the related art, the support structure can be a star frame. Therefore, reference can be made to Figure 4 Between at least two guide channels 2, there is also a bypass channel 3 for the support structure between the two control rods 1 to pass through, and the bypass channel 3 is connected to the guide channel 2. It can be understood that the number and size of the bypass channels 3 are determined according to the shape of the support structure. In other words, at least part of the guide structure 21 is also provided with a bypass opening 22 to communicate with the bypass channel 3.

[0069] Therefore, in order to allow the support mechanism to pass through, the second magnetic part 421 cannot be set at the avoidance opening 22, so the second magnetic part 421 will not be set at the hole wall on the opposite side of the guide structure 21 and the avoidance opening 22. Secondly, since the junction between the circumferential inner wall of the guide structure 21 and the avoidance opening 22 is a severely worn area, if a magnetic part is set here, the magnetic part is prone to severe wear, which will inevitably lead to asymmetric magnetic force distribution in the circumferential direction, which will increase the contact force of the friction pair; therefore, if Figure 4 As shown, there is a distance between the second magnetic portion 421 and the escape opening 22 .

[0070] exist Figure 1 In the embodiment shown, two second magnetic parts 421 are provided; on the circumference of the guide structure 21, the size of the central angle corresponding to the second magnetic part 421 is between 100° and 110°. The two second magnetic parts 421 are distributed on both sides of the symmetry axis in a mirror-symmetrical manner, with the shortest straight line between the center point of the avoidance opening 22 and the center axis of the guide structure 21 as the symmetry axis. The distances from both ends of the second magnetic part 421 to the symmetry axis are the same. Correspondingly, four first magnetic parts 411 are provided, and they are oriented toward the two second magnetic parts 421 in pairs. The width of each second magnetic part 421 in the circumferential direction is greater than the overall length of the two first magnetic parts 411 interacting with the second magnetic part 421 in the circumferential direction.

[0071] In summary, the control rod assembly of the present invention can generate repulsion between the first magnetic part 411 and the second magnetic part 421 through the first magnetic part 411 built into the control rod 1 and corresponding to the second magnetic part 421 arranged at the guide structure 21 (guide clamp hole and guide cylinder). When the control rod 1 is at the center of the guide channel 2, the magnets at relative positions are far away and the magnetic force is weak. Moreover, since the first magnetic part 411 and the second magnetic part 421 are evenly arranged in the circumferential direction, the repulsion is symmetrical, so it will not affect the normal positioning effect. When the control rod 1 shakes laterally due to factors such as flow field, stepping forward and stepping backward, the repulsion will increase as the distance between the magnets decreases, thereby hindering the lateral movement of the control rod 1, at least reducing the impact between the control rod 1 and the guide structure 21, and even preventing the abrasion between the control rod 1 and the guide structure 21.

[0072] In some embodiments, the diameter of the control rod 1 is between 9 mm and 9.8 mm, and the inner diameter of the guide tube is between 10 mm and 11 mm. The thickness of the magnetic part (the first magnetic part 411 and the second magnetic part 421) can be between 0.8 mm and 1.5 mm. It can be understood that since the thickness of the first magnetic part 411 and the second magnetic part 421 is small, the repulsive force is weak enough to avoid affecting the stability of the control rod 1 at other positions; at the same time, it can also avoid abrasion caused by the reverse displacement of the control rod 1 due to the repulsive force.

[0073] Secondly, the magnetic part can be made of high temperature resistant alloy or ferrite material, such as samarium cobalt magnet (SmCo, temperature range 250℃~350℃, most stable performance), ferrite magnet and aluminum nickel cobalt magnet (temperature range 500℃~600℃, slightly poor performance stability). Since the magnetic part used in the control rod 1 and the guide structure 21 has high requirements on shape and size accuracy, composite permanent magnetic material can be used to manufacture the magnetic part. For example, the composite permanent magnetic material can be a composite of permanent magnetic material powder and a binder.

[0074] The lubricating coating 5 will be described below.

[0075] In some embodiments, Figure 2 and Figure 4 For reference, a first lubricating coating 5 is laid on the circumferential outer wall of the cladding 11 of the control rod 1, and a second lubricating coating 5 is also laid on the circumferential side wall of the guide channel 2. It should be noted that the first lubricating coating 5 and the second lubricating coating 5 can be the same lubricating coating 5, and the purpose here is to distinguish the different laying positions.

[0076] Since the first magnetic component 41 is arranged on the side of the first lubricating coating 5 facing away from the circumferential side wall of the guide channel 2, and the second magnetic component 42 is arranged on the side of the second lubricating coating 5 facing away from the control rod 1, the first lubricating coating 5 and the second lubricating coating 5 can not only reduce the abrasion damage between the control rod 1 and the guide channel 2, but also protect the first magnetic component 41 and the second magnetic component 42.

[0077] The thickness of the lubricating coating 5 may be between 0.1 mm and 0.5 mm. It is understandable that if the thickness of the lubricating coating 5 is too small, the lubrication effect and durability will be affected, while if the thickness of the lubricating coating 5 is too large, the stepping forward and stepping backward of the control rod 1 will be affected.

[0078] The lubricating coating 5 may be a high temperature resistant solid self-lubricating coating, which may include: a metal-based high temperature self-lubricating coating, a metal ternary oxide-based self-lubricating coating, and a ceramic-based high temperature self-lubricating coating.

[0079] Understandably, metal-based high-temperature self-lubricating coatings, such as Ni3Al-based composite self-lubricating coatings 5, NiCr / Cr3C2-BaF2·CaF2 composite coatings, NiCr / Cr3C2-WS2-CaF2 composite self-lubricating coatings 5, NiCr-WSe2-h-BN-BaF2·CaF2 composite coatings, Co-based self-lubricating composite materials, etc. The advantage is that they have good self-lubricating properties in a wide temperature range, and the friction coefficient is maintained at 0.23-0.33 within 30℃-800℃. A continuous and smooth metal acid salt enamel layer can be formed on the wear surface under high temperature environment, which greatly reduces the friction coefficient and wear rate of the coating. The disadvantage is that when there are periodic changes in high and low temperatures, new phases will be generated on the coating surface, resulting in fatigue contact failure, and once consumed, it cannot be regenerated.

[0080] Metal ternary oxide-based self-lubricating coatings, such as PbMoO2, Ag3VO4, AgNbO3, AgTaO3 high-temperature lubricating hard film coatings, as well as metal nitride (VN, NbN, TaN)-Ag solid self-lubricating coatings 5, Ag2MoO4 high-temperature lubricating phases and other materials. The advantage is that it can maintain a good self-lubricating state at high temperatures of 700℃-1000℃, and can meet the sustainable lubrication requirements from room temperature to high temperatures of 1000℃. The disadvantage is that its oxidation rate is relatively fast under high temperature conditions, and as the oxide layer is worn and consumed, it may not support the role of long-term protection of the control rods 1 in the reactor.

[0081] Ceramic-based high-temperature self-lubricating coatings, such as the MoS2 / YSZ / Au / DLC series, are based on ceramic phases or nitrides (ZrO2(Y2O3), Al2O3, CrN), and are prepared using magnetron sputtering pulsed laser co-deposition technology to produce coating materials, as well as Al2O3 / Mo layered self-lubricating structural ceramics, Al2O3 / TiC / CaF2 gradient composite materials, CF / Al2O3 self-lubricating composite materials, etc. The friction coefficient is 0.1-0.3 at a high temperature of 500°C, and the chemical composition, structure and mechanical properties of the friction surface can be automatically changed by using external loads and environmental changes, thereby achieving the purpose of lubrication. The advantages are that ceramic materials have high hardness, low density, and good high-temperature strength stability; for example, (ZrO2(Y2O3) ceramics have excellent wear resistance, toughness and strength. The disadvantage is that the friction coefficient is relatively high.

[0082] Therefore, according to the actual working conditions on site, the above-mentioned high-temperature solid self-lubricating coating 5 can be used for setting. Secondly, considering the simplicity of the process, adaptability and the complexity of the surface structure of high-temperature parts, the process of realizing the coating material on the surface of the control rod 1 and the guide structure 21 can be realized by supersonic thermal spraying or laser cladding technology.

[0083] In summary, the control rod assembly of the present invention improves the anti-abrasion performance of the control rod 1 mainly in two ways. One way is: the first magnetic part 411 built into the control rod 1 and the second magnetic part 421 of the guide channel 2 are in corresponding positions, and repulsion is generated between the magnets; when the control rod 1 is in the radial center position, the magnets at relative positions are far away, the magnetic force is weak, and because the repulsion is symmetrical, it will not affect the normal positioning effect. At the same time, the thickness of the permanent magnet strip is small enough, the repulsion is weak enough, and the stability of the control rod 1 at other positions is also avoided; and when the control rod 1 produces lateral shaking due to factors such as flow field or stepping forward / stepping backward, the repulsion will increase as the distance between the magnets decreases, thereby hindering the lateral movement of the control rod 1 and reducing the impact between the control rod 1 and the guide card or the continuous guide segment. Another method is: the high temperature resistant solid self-lubricating coating 5 on the surface of the control rod 1 and the guide structure 21 is used to reduce the friction coefficient between the two, reduce the abrasion damage between the control rod 1 cladding 11 and the guide structure 21, and delay the abrasion rate of the control rod 1 cladding 11, thereby extending the service life of the control rod 1.

[0084] Through the scheme of improving the control rod assembly of the present application, the impact of abrasion on the control rod 1 can be reduced, the service life of the control rod 1 can be effectively extended, and the cost of frequently replacing damaged rods can be saved; in addition, since the risk of strength reduction of the control rod 1 due to abrasion is reduced, the safety of the reactor in an emergency shutdown situation can be improved.

[0085] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, the above technical features can be freely combined without departing from the concept of the present invention, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the coverage of the claims of the present invention.

Claims

1. A control rod assembly, comprising a plurality of control rods (1) and a control rod guide tube assembly; the control rod guide tube assembly is provided with a plurality of guide channels (2), each of the control rods (1) is inserted into a corresponding guide channel (2), characterized in that: The control rod assembly further comprises a repulsion structure (4) arranged between each group of the guide channels (2) and the control rods (1), wherein the repulsion structure (4) is used to generate a force preventing the control rods (1) from approaching the circumferential side walls of the guide channels (2).

2. The control rod assembly according to claim 1, characterized in that: The repulsive structure (4) comprises a first magnetic component (41) mounted on the control rod (1), and a second magnetic component (42) mounted on the side wall of the guide channel (2); the first magnetic component (41) and the second magnetic component (42) are arranged to repel each other.

3. The control rod assembly according to claim 2, characterized in that: The control rod (1) comprises a cylindrical cladding (11) and an absorbent core block (12) arranged in the cladding (11); the first magnetic component (41) comprises at least three first magnetic parts (411) in the form of elongated strips, which are respectively embedded between the cladding (11) and the absorbent core block (12) and are evenly spaced and arranged in a circumferential direction of the control rod (1); the length direction of each first magnetic part (411) is parallel to the axial direction of the absorbent core block (12).

4. The control rod assembly according to claim 3, characterized in that: Each of the guide channels (2) is defined by a plurality of guide structures (21); the plurality of guide structures (21) include guide cylinders and a plurality of guide clamping holes arranged on the same longitudinal straight line; The second magnetic component (42) includes a plurality of second magnetic parts (421) embedded in the circumferential direction of each of the guide structures (21); all of the first magnetic parts (411) are evenly arranged to interact with the corresponding second magnetic parts (421), and the circumferential length of each of the second magnetic parts (421) is greater than the overall circumferential length of the first magnetic part (411) interacting with the second magnetic part (421).

5. The control rod assembly according to claim 4, characterized in that: The control rod assembly further comprises a support structure, the plurality of control rods (1) being mounted on the support structure; the guide structure (21) being provided with an escape opening (22) for a portion of the support structure to pass through; The plurality of second magnetic portions (421) are distributed on both sides of the symmetry axis in a mirror-symmetrical manner, with the shortest straight line between the center point of the avoidance opening (22) and the center axis of the guide structure (21) as the symmetry axis; and, in the circumferential direction, each of the second magnetic portions (421) maintains a distance from the avoidance opening (22).

6. The control rod assembly according to claim 5, characterized in that The first magnetic component (41) comprises four first magnetic parts (411), each of the first magnetic parts (411) is a long magnetic strip, and its length is equivalent to the length of the absorbent core block (12); Each of the guide structures (21) is provided with two symmetrically arranged second magnetic parts (421), and each of the second magnetic parts (421) is an arc-shaped magnetic strip; on the circumference of the guide structure (21), the size of the central angle corresponding to the second magnetic part (421) is between 100° and 110°; The four first magnetic parts (411) are oriented toward the surfaces of the two second magnetic parts (421) in pairs.

7. The control rod assembly according to any one of claims 4 to 6, characterized in that: The circumferential outer wall of the absorbent core block (12) and / or the circumferential side wall of the guide structure (21) is provided with a mounting groove (43) for inserting the corresponding magnetic part; the corresponding magnetic part is the first magnetic part (411) or the second magnetic part (421); A limiting structure (44) is provided between the installation groove (43) and the corresponding magnetic portion to limit the corresponding magnetic portion from being separated from the installation groove (43); The mounting groove (43) is a trapezoidal slot, and at least one groove side wall of the mounting groove (43) and the groove bottom wall of the mounting groove (43) form an acute angle region as the limiting structure (44) to clamp a portion of the structure of the corresponding magnetic part; Alternatively, the limiting structure (44) includes a protruding portion provided at one of the mounting groove (43) and the corresponding magnetic portion, and a recessed portion provided at the other of the mounting groove (43) and the corresponding magnetic portion; the protruding portion is inserted into the recessed portion.

8. The control rod assembly according to claim 2, characterized in that: The first magnetic assembly (41) comprises at least three first magnetic parts (411) arranged in a circumferential direction of the control rod (1); Each of the guide channels (2) is defined by a plurality of guide structures (21); the plurality of guide structures (21) include guide cylinders and a plurality of guide clamping holes arranged on the same longitudinal straight line; the second magnetic component (42) includes a plurality of second magnetic parts (421) embedded in the circumference of each of the guide structures (21); All the first magnetic parts (411) are evenly arranged to interact with the corresponding second magnetic parts (421), and the thickness of the first magnetic parts (411) and / or the second magnetic parts (421) is between 0.8 mm and 1.5 mm.

9. The control rod assembly according to any one of claims 1 to 6 or 8, characterized in that: A lubricating coating (5) is provided on at least one of the circumferential side walls of the guide channel (2) and the circumferential side walls of the control rod (1).

10. The control rod assembly according to claim 9, characterized in that The lubricating coating (5) is a high-temperature resistant solid self-lubricating coating; the high-temperature resistant solid self-lubricating coating comprises one of a metal-based high-temperature self-lubricating coating, a metal ternary oxide-based self-lubricating coating and a ceramic-based high-temperature self-lubricating coating.

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