Control rod absorber

Abstract

The application discloses a control rod absorption rod, which comprises a cladding tube, an upper head connected to the upper end of the cladding tube, a lower head connected to the lower end of the cladding tube, an elastic member arranged in the cladding tube and connected to the upper head at one end, and a boron carbide absorption body assembly packaged in the cladding tube. Compared with the conventional absorption rod in which the absorption body adopts a flat contact mode, the convex part and the groove part are used to position the several sub-absorption bodies, the top absorption body and the several sub-absorption bodies can be positioned at the inner central position of the cladding tube, the eccentricity problem of the absorption body is effectively solved, the swelling life of the absorption body is ensured, the contact area between the absorption bodies is increased, the contact surface stress is reduced, and the risk of absorption body fragmentation is reduced.

Description

Technical Field

[0001] This invention relates to the field of nuclear reactor fuel, and more particularly to a control rod absorber rod. Background Technology

[0002] A typical pressurized water reactor control rod consists of a neutron absorber, a cladding tube, a clamping spring, and upper and lower end plugs. The neutron absorber and clamping spring are sealed within the cladding tube, which is welded with upper and lower end plugs. A single absorber is usually a cylindrical structure, stacked one on top of the other to form an absorber section.

[0003] Because absorbers typically undergo irradiation swelling during in-reactor irradiation, a certain gap is usually designed between the absorber and the cladding to accommodate the swelling. This results in the radial position of individual absorber cylinders being unstable, leading to eccentric absorber positioning. Consequently, the gap between the absorber and the cladding on one side decreases, thus reducing the absorber's swelling lifetime. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a control rod absorber.

[0005] The technical solution adopted by the present invention to solve its technical problem is: to construct a control rod absorber rod, which includes a casing tube, an upper end cap connected to the upper end of the casing tube, a lower end cap connected to the lower end of the casing tube, an elastic element disposed in the casing tube and connected at one end to the upper end cap, and a boron carbide absorber assembly encapsulated in the casing tube.

[0006] The boron carbide absorber assembly includes a top absorber and several sub-absorbers. The end of the elastic member away from the upper end cap is connected to the top absorber. The several sub-absorbers are located between the top absorber and the lower end cap. The top absorber includes a top absorber body and a docking portion disposed at the end away from the elastic member. Each sub-absorber includes a sub-absorber body, a protrusion and a groove respectively disposed at both ends of the sub-absorber body. The protrusion and the groove are matched and disposed. The end of the lower end cap facing the upper end cap is provided with a connecting portion that matches the protrusion or the groove. The docking portion matches the protrusion or the groove.

[0007] In some embodiments, the protrusion is an arc-shaped protrusion structure, and the groove is an arc-shaped groove structure that matches the arc-shaped protrusion structure.

[0008] In some embodiments, the central axis of the top absorbent body, the central axis of the docking portion, the central axis of the sub-absorbent body, the central axis of the protrusion, and the central axis of the groove are aligned.

[0009] In some embodiments, the protrusion is located on the side of the sub-absorbent body facing the top absorber, and the groove is located on the side of the sub-absorbent body away from the protrusion.

[0010] In some embodiments, the upper end cap is connected to the casing tube by welding and / or the lower end cap is connected to the encapsulation casing tube by welding.

[0011] In some embodiments, the elastic element is a compression spring.

[0012] In some embodiments, the upper end cap is provided with an upper end embedding portion that is embedded in the upper end of the casing tube, and the lower end cap is provided with a lower end embedding portion that is embedded in the lower end of the casing tube. The lower end embedding portion is located on the side of the connecting portion away from the boron carbide absorber assembly.

[0013] In some embodiments, the maximum outer diameter of the upper embedded portion is smaller than the inner diameter of the casing tube, and the maximum outer diameter of the lower embedded portion is smaller than the inner diameter of the casing tube.

[0014] In some embodiments, the upper end cap is provided with an exhaust port for discharging the gas generated by the boron carbide absorber.

[0015] In some embodiments, the vent hole has a T-shaped structure.

[0016] The present invention has the following advantages: Compared with conventional absorbent rods where the absorbent body adopts a planar contact method, the control rod absorbent rod uses protrusions and grooves to position the sub-absorbent bodies. This can position the top absorbent body and the sub-absorbent bodies at the center of the inner part of the casing tube, effectively solving the problem of absorbent body eccentricity. This ensures that there is sufficient swelling gap between the absorbent body and the casing tube, ensuring the swelling life of the absorbent body. At the same time, it can increase the contact area between the absorbent bodies, thereby reducing the stress on the contact surface and reducing the risk of absorbent body breakage. Attached Figure Description

[0017] To more clearly illustrate the technical solution of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort. In the drawings:

[0018] Figure 1 These are exploded structural diagrams of the control rod and absorber rod in some embodiments of the present invention;

[0019] Figure 2 This is a three-dimensional structural diagram of the control rod and absorber rod after assembly in some embodiments of the present invention;

[0020] Figure 3 These are cross-sectional views of the control rod absorber in some embodiments of the present invention;

[0021] Figure 4 This is a schematic diagram of the lower end cap structure in some embodiments of the present invention;

[0022] Figure 5 This is a schematic diagram of the structure of the absorber in some embodiments of the present invention. Detailed Implementation

[0023] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific embodiments are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or element referred to must have a specific orientation; therefore, they should not be construed as limitations on this invention.

[0024] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary components. The terms "first," "second," "third," etc., are only for the convenience of describing this technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0025] Please see Figures 1 to 5This is a control rod absorber rod in some embodiments of the present invention. The absorber rod is specifically applied to the control rod of a pressurized water reactor and can position the absorber. The control rod absorber rod includes a cladding tube 1, an upper end cap 2 connected to the upper end of the cladding tube 1, a lower end cap 3 connected to the lower end of the cladding tube 1, an elastic element 4 disposed inside the cladding tube 1 and connected at one end to the upper end cap 2, and a boron carbide absorber assembly 5 encapsulated inside the cladding tube 1.

[0026] More specifically, the casing tube 1 is cylindrical, and the boron carbide absorber assembly 5 is housed in the inner cavity of the casing tube 1. The upper end cap 2 is used to seal the upper end of the casing tube 1, and the lower end cap 3 is used to seal the lower end of the casing tube 1. The boron carbide absorber assembly 5 is located between the upper end cap 2 and the lower end cap 3. The upper end cap 2 and the lower end cap 3 simultaneously seal both ends of the casing tube 1 and also seal the boron carbide absorber assembly 5. This can control the powder particles generated after the boron carbide absorber assembly 5 irradiates and swells, confining them within the casing tube 1 and avoiding affecting the service life of the control rod absorber.

[0027] like Figure 1 and Figure 3 As shown, the boron carbide absorber assembly 5 includes a top absorber 51 and several sub-absorbers 52, which are arranged along the axial direction of the casing tube 1. An elastic member 4, located away from the upper end cap 2, is connected to the top absorber 51. This elastic member 4 is used to press the boron carbide absorber assembly 5 into the casing tube 1; preferably, it is a compression spring. Furthermore, several sub-absorbers 52 are located between the top absorber 51 and the lower end cap 3. The top absorber 51 includes a top absorber body 511 and a mating portion 512 located away from the elastic member 4. Each sub-absorber 52 includes a sub-absorber body 521, protrusions 522 and grooves 523 located at both ends of the sub-absorber body 521, with the protrusions 522 and grooves 523 matched. The lower end cap 3, facing the upper end cap 2, has a connecting portion 31 that matches either the protrusions 522 or the grooves 523, with the mating portion 512 matching either the protrusions 522 or the grooves 523. In this embodiment, the docking portion 512 is a protruding structure that matches the shape of the protrusion portion 522.

[0028] In addition, the central axis of the top absorption body 511, the central axis of the docking part 512, the central axis of the sub-absorption body 521, the central axis of the protrusion 522, and the central axis of the groove 523 are aligned.

[0029] Understandably, compared to conventional absorber rods where the absorber body uses a planar contact method, the several sub-absorbers 52 are positioned with protrusions 522 and grooves 523. This allows the top absorber 51 and the several sub-absorbers 52 to be positioned at the center of the inner casing tube 1, effectively solving the problem of absorber eccentricity. This ensures sufficient swelling gap between the absorber body and the casing tube 1, ensuring the swelling life of the absorber body. At the same time, it can increase the contact area between the absorbers, thereby reducing the stress on the contact surface and lowering the risk of absorber body breakage.

[0030] Preferably, the protrusion 522 is an arc-shaped protrusion structure, and the groove 523 is an arc-shaped groove structure that matches the arc-shaped protrusion structure. The protrusion 522 and the groove 523 cooperate and constrain each other. Through this cooperation and assembly, the position of the absorber can be ensured to be located at the center of the casing tube 1. At the same time, the arc-shaped structure is convenient for processing and assembly, and can fully increase the contact area between absorbers and reduce the stress on the contact surface. In some other embodiments, the protrusion 522 may be a square protrusion structure, a triangular protrusion structure, or other shapes, and the groove 523 may be a shape corresponding to the protrusion 522. No specific limitation is made here.

[0031] In this embodiment, the protrusion 522 is located on the side of the sub-absorbent body 521 facing the top absorber 51, and the groove 523 is located on the side of the sub-absorbent body 521 facing away from the protrusion 522. In some other embodiments, the positions of the protrusion 522 and the groove 523 can be interchanged, which is not specifically limited here.

[0032] In addition, in order to seal the casing tube 1 with the upper end cap 2 and the lower end cap 3, the upper end cap 2 is connected to the casing tube 1 by welding, and the lower end cap 3 is connected to the casing tube 1 by welding.

[0033] Furthermore, the upper end cap 2 is provided with an upper end embedding portion 22 for embedding into the upper end of the casing tube 1, and the lower end cap 3 is provided with a lower end embedding portion 32 for embedding into the lower end of the casing tube 1. The lower end embedding portion 32 is located on the side of the connecting portion 31 opposite to the boron carbide absorber assembly 5. When the lower end embedding portion 32 is embedded into the lower end of the casing tube 1, the connecting portion 31 of the lower end cap 3 extends into the casing tube 1 and connects with the boron carbide absorber assembly 5. The maximum outer diameter of the upper end embedding portion 22 is smaller than the inner diameter of the casing tube 1, and the maximum outer diameter of the lower end embedding portion 32 is smaller than the inner diameter of the casing tube 1, so that the upper end cap 2 and the lower end cap 3 can be welded together.

[0034] In addition, the upper end cap 2 is provided with an exhaust port for discharging the gas generated by the boron carbide absorber assembly 5, which is preferably T-shaped. This exhaust port allows the gas generated by the boron carbide absorber assembly 5 to be discharged from the casing tube 1. Because the exhaust port is T-shaped, the gas generated by the boron carbide absorber assembly 5 can be discharged from both end faces of the upper end cap 2.

[0035] When assembling the control rod absorber, the lower end cap 3 is first welded to the casing tube 1. Then, the top absorber 51 and several sub-absorbers 52 are inserted into the casing tube 1 with the protrusions 522 facing upwards, and the center of the boron carbide absorber assembly 5 is automatically aligned.

[0036] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A control rod absorber, characterized in that, It includes a casing tube (1), an upper end cap (2) connected to the upper end of the casing tube (1), a lower end cap (3) connected to the lower end of the casing tube (1), an elastic element (4) disposed inside the casing tube (1) and connected at one end to the upper end cap (2), and a boron carbide absorber assembly (5) encapsulated inside the casing tube (1). The boron carbide absorber assembly (5) includes a top absorber (51) and a plurality of sub-absorbers (52). The end of the elastic member (4) away from the upper end cap (2) is connected to the top absorber (51). The plurality of sub-absorbers (52) are located between the top absorber (51) and the lower end cap (3). The top absorber (51) includes a top absorber body (511) and a docking portion (512) provided at the end away from the elastic member (4). Each sub-absorber (52) includes a sub-absorber body (521), a protrusion (522) and a groove (523) respectively provided at both ends of the sub-absorber body (521). The protrusion (522) and the groove (523) are matched and provided. The lower end cap (3) is provided with a connecting part (31) on one end facing the upper end cap (2) that matches the protrusion (522) or the groove (523), and the mating part (512) matches the protrusion (522) or the groove (523); The protrusion (522) is an arc-shaped protrusion structure, and the groove (523) is an arc-shaped groove structure that matches the arc-shaped protrusion structure.

2. The control rod absorber according to claim 1, characterized in that, The central axis of the top absorber (511), the central axis of the docking part (512), the central axis of the sub-absorber (521), the central axis of the protrusion (522), and the central axis of the groove (523) are aligned.

3. The control rod absorber according to claim 1, characterized in that, The protrusion (522) is located on the side of the sub-absorbent body (521) facing the top absorber (51), and the groove (523) is located on the side of the sub-absorbent body (521) facing away from the protrusion (522).

4. The control rod absorber according to claim 1, characterized in that, The upper end cap (2) is connected to the shell tube (1) by welding, and the lower end cap (3) is connected to the shell tube (1) by welding.

5. The control rod absorber according to claim 1, characterized in that, The elastic element (4) is a compression spring.

6. The control rod absorber according to claim 1, characterized in that, The upper end cap (2) is provided with an upper end embedding part (22) that is embedded in the upper end of the shell tube (1), and the lower end cap (3) is provided with a lower end embedding part (32) that is embedded in the lower end of the shell tube (1). The lower end embedding part (32) is located on the side of the connecting part (31) away from the boron carbide absorber assembly (5).

7. The control rod absorber according to claim 6, characterized in that, The maximum outer diameter of the upper embedded part (22) is smaller than the inner diameter of the casing tube (1), and the maximum outer diameter of the lower embedded part (32) is smaller than the inner diameter of the casing tube (1).

8. The control rod absorber according to claim 1, characterized in that, The upper end cap (2) is provided with an exhaust port for discharging the gas generated by the boron carbide absorber assembly (5).

9. The control rod absorber according to claim 8, characterized in that, The exhaust port has a T-shaped structure.

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