Control rod with moderated rod follower

Abstract

The invention provides a control rod with a moderation rod follower, the control rod comprises the follower, the follower comprises a moderation rod, a sleeve and a buffer part, the sleeve sleeves the moderation rod, the buffer part is connected with the sleeve, and the buffer part is arranged at the bottom of the moderation rod to apply upward elastic force to the moderation rod. The casing pipe is arranged outside the moderation rod, so that external protection can be formed on the moderation rod, and the moderation rod is prevented from directly bearing external impact. The buffer part is arranged at the bottom of the moderation rod and the upward elastic force is applied, so that the impact force is effectively absorbed and relieved when large impact force is generated during rod falling of the control rod, the possibility that the moderation rod made of a brittle material is damaged due to impact is greatly reduced, and the structural integrity and the use stability of the moderation rod are guaranteed. Besides, the moderation rod can improve the value of the control rod by compensating the reactivity of the reactor core, the moderation rod can be ensured to stably play a role while the moderation rod is protected, the control effect of the control rod on the reactivity of the reactor is further ensured, and the safety and the reliability of the operation of the reactor are improved.

Description

Technical Field

[0001] This application belongs to the field of nuclear reactor core technology, specifically relating to a control rod with a moderator rod follower. Background Technology

[0002] The reactor core mainly consists of fuel assemblies, control rod assemblies, stationary related assemblies, and structural and experimental components placed inside the reactor. The main function of the control rod assembly is as a neutron absorber, driven by a drive system to move within the reactor, control reactivity, enable reactor startup and normal shutdown, regulate and maintain reactor power, and ensure reactor safety under accident conditions.

[0003] Currently, control rod assemblies are typically monolithic structures, with each control rod employing a single neutron absorber. The reactivity of the reactor core can be compensated by placing a moderator rod follower below the neutron absorber, thereby increasing the value of the control rod. However, since the commonly used materials for moderator rods, such as beryllium, beryllium oxide, yttrium hydride, and zirconium hydride, are brittle materials with poor mechanical properties, the impact force generated when the control rod is dropped is significant, causing considerable damage to these brittle materials and easily leading to breakage. Summary of the Invention

[0004] Therefore, the technical problem to be solved by this application is to provide a control rod with a moderating rod follower, which can reduce the possibility of damage to the moderating rod.

[0005] To address the aforementioned problems, this application provides a control rod with a moderating rod follower, comprising a follower, the follower including a moderating rod, a sleeve, and a buffer portion, the sleeve being sleeved on the moderating rod, the buffer portion being connected to the sleeve, and the buffer portion being disposed at the bottom of the moderating rod to apply an upward elastic force to the moderating rod.

[0006] Optionally, the buffer section includes a connector and an elastic element. The connector is connected to the sleeve, and the elastic element is disposed inside the connector and is grounded to the bottom of the moderating rod.

[0007] Optionally, the elastic element includes a spring, the connector is provided with a mounting groove, the spring is disposed in the mounting groove, and the spring, the mounting groove and the slowing rod are coaxially arranged.

[0008] Optionally, the follower further includes a first end plug, through which the connector is connected to the sleeve. The first end plug is located at the bottom of the sleeve to limit the movement of the moderating rod.

[0009] Optionally, the first end plug is sleeved in the sleeve near one end of the moderator rod, the connecting piece is sleeved in the first end plug near one end of the moderator rod, and the elastic piece abuts against the bottom of the moderator rod through the first end plug.

[0010] Optionally, the connecting piece is screwed with the first end plug, the first end plug is provided with a fixing pin in the radial direction, and the fixing pin abuts against the outer peripheral wall of the connecting piece.

[0011] Optionally, the bottom of the mounting groove is provided with a liquid passing hole penetrating through the bottom of the mounting groove in the axial direction of the control rod.

[0012] Optionally, the follower comprises a lower joint, and one end of the connecting piece away from the moderator rod is sleeved with the lower joint.

[0013] Optionally, the follower comprises a second end plug, the second end plug is sleeved with the sleeve, and the second end plug is located at the top of the sleeve to limit the moderator rod. The follower comprises an upper joint, the upper joint is screwed with the top of the second end plug, the second end plug is provided with a fixing pin in the radial direction, and the fixing pin abuts against the outer peripheral wall of the upper joint.

[0014] Optionally, the control rod comprises an absorbing section and a driving mechanism connecting piece, and the absorbing section, the follower and the driving mechanism connecting piece are sequentially and detachably connected in the axial direction of the control rod.

[0015] Beneficial effects: The control rod with the moderator rod follower provided in the embodiment of the application can form external protection for the moderator rod by arranging the sleeve outside the moderator rod, so that the moderator rod can avoid directly bearing external impact. The buffer part is arranged at the bottom of the moderator rod and an upward elastic force is applied, so that when the control rod falls and a large impact force is generated, the buffer part can effectively absorb and relieve the impact force, greatly reduces the possibility that the moderator rod made of brittle material is damaged due to impact, and guarantees the structural integrity and use stability of the moderator rod. In addition, the moderator rod can improve the control rod value through compensation of the core reactivity, can ensure that the moderator rod stably plays a role while protecting the moderator rod, and then guarantees the control effect of the control rod on the reactivity of the reactor, and improves the safety and reliability of the operation of the reactor. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a schematic diagram of the three-dimensional structure of the control rod of the embodiment of the application; Figure 2 It is a schematic diagram of the three-dimensional structure of the control rod of the embodiment of the application; Figure 1 It is an enlarged view of A in FIG. 4; Figure 3A structure schematic view of the connecting piece of the embodiment of the present application from a first perspective; Figure 4 A structure schematic view of the connecting piece of the embodiment of the present application from a second perspective; Figure 5 A sectional view of the connecting piece of the embodiment of the present application.

[0017] The signs are as follows: 1, moderator rod; 2, sleeve; 31, connecting piece; 311, mounting groove; 312, liquid passage; 32, elastic piece; 4, first end plug; 51, lower joint; 52, upper joint; 6, absorption section; 7, follower. DETAILED DESCRIPTION

[0018] In the description of the present application, it needs to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0019] In addition, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly specified and limited.

[0020] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium, or can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0021] The preferred embodiments of the present application are described below in conjunction with the drawings, and it should be understood that the preferred embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0022] For reference Figures 1 to 5As shown, according to the embodiment of the present application, a control rod with a moderator rod follower is provided, which comprises a follower 7, the follower 7 comprises a moderator rod 1, a sleeve 2 sleeved on the moderator rod 1, and a buffer part connected with the sleeve 2, and the buffer part is arranged at the bottom of the moderator rod 1 to apply an elastic force upward to the moderator rod 1.

[0023] By arranging the sleeve 2 outside the moderator rod 1, the moderator rod 1 can be externally protected to avoid being directly subjected to external impact. The buffer part arranged at the bottom of the moderator rod 1 and applying an elastic force upward can effectively absorb and relieve the impact force when the control rod is dropped, greatly reducing the possibility of damage to the moderator rod 1 made of brittle material due to impact, and ensuring the structural integrity and use stability of the moderator rod 1. In addition, the moderator rod 1 can improve the control rod value through core reactivity compensation. While protecting the moderator rod 1, the moderator rod 1 can stably play a role, thereby ensuring the control effect of the control rod on the reactor reactivity and improving the safety and reliability of the reactor operation.

[0024] Among them, the moderator rod 1 and the sleeve 2 are coaxially sleeved, the moderator rod 1, the sleeve 2 and the control rod are all substantially cylindrical structures, and the three are coaxially arranged.

[0025] Among them, the vertical arrangement is arranged below the moderator rod 1, the buffer part has elasticity, and then applies an elastic force upward to the moderator rod 1 through its own elasticity, thereby forming a buffer.

[0026] The buffer part comprises a connecting piece 31 and an elastic piece 32, the connecting piece 31 is connected with the sleeve 2, the elastic piece 32 is arranged in the connecting piece 31, and the elastic piece 32 is in abutment with the bottom of the moderator rod 1.

[0027] By connecting the buffer part of the control rod with the sleeve 2 through the connecting piece 31, a stable installation and support basis can be provided for the elastic piece 32, ensuring that the elastic piece 32 is always in a preset position during the operation of the control rod, and avoiding the failure of the buffer due to the position deviation. By arranging the elastic piece 32 in the connecting piece 31 and abutting with the bottom of the moderator rod 1, the elastic force of the elastic piece 32 can be accurately and stably applied to the moderator rod 1. When the control rod is dropped, the elastic piece 32 can efficiently absorb the impact energy, further weaken the impact force on the moderator rod 1, and reduce the risk of damage to the brittle moderator rod 1. This structural design not only ensures the stability of the connection between the buffer part and the sleeve 2, but also ensures the reliable play of the buffer function of the elastic piece 32, thereby providing continuous and effective protection for the moderator rod 1, and further ensuring the operation stability and service life of the control rod as a whole, and maintaining its good control ability on the core reactivity.

[0028] Among them, the top end of the elastic piece 32 is in abutment with the bottom of the moderator rod 1, and the bottom end of the elastic piece 32 is connected with the connecting piece 31.

[0029] The connector 31 is fixedly connected to the sleeve 2.

[0030] The materials used for moderator rod 1 include metallic beryllium, beryllium oxide, yttrium hydride, and zirconium hydride. Moderator materials have a small thermal neutron absorption cross section and a large neutron scattering cross section, which is beneficial for increasing the value of the control rod and thus improving the reactor core reactivity control capability.

[0031] The elastic element 32 includes a spring, the connecting element 31 is provided with a mounting groove 311, the spring is disposed in the mounting groove 311, and the spring, the mounting groove 311 and the slowing rod 1 are coaxially arranged.

[0032] The elastic element 32 is specifically designed as a spring. Utilizing the spring's mature elastic buffering characteristics, it can stably absorb impact energy when the control rod falls, effectively weakening the impact force on the moderator rod 1 and reducing the risk of damage to the brittle moderator rod 1. An installation groove 311 is provided on the connector 31, providing precise installation and positioning space for the spring, preventing spring misalignment during force application and ensuring stable buffering performance. By coaxially aligning the spring, installation groove 311, and moderator rod 1, the elastic force of the spring on the moderator rod 1 is precisely transmitted along the control rod axis, preventing additional lateral forces from causing damage to the moderator rod 1 due to force misalignment. This further ensures the structural integrity of the moderator rod 1, improves the reliability and stability of the buffer structure, and continuously protects the moderator rod 1, ensuring its stable performance in compensating for core reactivity and enhancing the value of the control rod. This, in turn, guarantees the control rod's effectiveness in controlling core reactivity and enhances reactor operation safety.

[0033] The connector 31 has an installation groove 311 along the vertical direction. The groove of the installation groove 311 is set upward and is opposite to the bottom of the moderating rod 1. The spring is vertically inserted into the installation groove 311.

[0034] The spring is vertically installed in the mounting groove 311, with the top center of the spring opposite to the bottom center of the moderating rod 1.

[0035] The follower 7 also includes a first end plug 4. The connector 31 is connected to the sleeve 2 through the first end plug 4. The first end plug 4 is located at the bottom of the sleeve 2 to limit the slowing rod 1.

[0036] The first end plug 4 is arranged at the bottom of the sleeve 2, and the connecting piece 31 is connected between the first end plug 4 and the sleeve 2, so that the buffer part is stably assembled with the sleeve 2, the first end plug 4 can effectively limit the position of the moderator rod 1, and the collision between the moderator rod 1 and other components during the operation or falling of the control rod is avoided, and the structural safety of the moderator rod 1 is further ensured. The limiting effect of the first end plug 4 can ensure that the moderator rod 1 is always in the preset working position in the sleeve 2, so that the moderator rod 1 can stably compensate the reactivity of the core, ensure the effective improvement of the value of the control rod, strengthen the stability of the connection between the buffer part and the sleeve 2, further protect the moderator rod 1, reduce the possibility of damage of the brittle moderator rod 1 due to displacement or collision, and further improve the operation reliability of the control rod as a whole, ensure the control effect of the control rod on the reactivity of the core of the reactor, and enhance the safety of the operation of the reactor.

[0037] The first end plug 4 is arranged at the bottom of the sleeve 2, and the connecting piece 31 is connected between the first end plug 4 and the sleeve 2, so that the buffer part is stably assembled with the sleeve 2, the first end plug 4 can effectively limit the position of the moderator rod 1, and the collision between the moderator rod 1 and other components during the operation or falling of the control rod is avoided, and the structural safety of the moderator rod 1 is further ensured. The limiting effect of the first end plug 4 can ensure that the moderator rod 1 is always in the preset working position in the sleeve 2, so that the moderator rod 1 can stably compensate the reactivity of the core, ensure the effective improvement of the value of the control rod, strengthen the stability of the connection between the buffer part and the sleeve 2, further protect the moderator rod 1, reduce the possibility of damage of the brittle moderator rod 1 due to displacement or collision, and further improve the operation reliability of the control rod as a whole, ensure the control effect of the control rod on the reactivity of the core of the reactor, and enhance the safety of the operation of the reactor.

[0038] The first end plug 4 is arranged at the bottom of the sleeve 2, and the connecting piece 31 is connected between the first end plug 4 and the sleeve 2, so that the buffer part is stably assembled with the sleeve 2, the first end plug 4 can effectively limit the position of the moderator rod 1, and the collision between the moderator rod 1 and other components during the operation or falling of the control rod is avoided, and the structural safety of the moderator rod 1 is further ensured. The limiting effect of the first end plug 4 can ensure that the moderator rod 1 is always in the preset working position in the sleeve 2, so that the moderator rod 1 can stably compensate the reactivity of the core, ensure the effective improvement of the value of the control rod, strengthen the stability of the connection between the buffer part and the sleeve 2, further protect the moderator rod 1, reduce the possibility of damage of the brittle moderator rod 1 due to displacement or collision, and further improve the operation reliability of the control rod as a whole, ensure the control effect of the control rod on the reactivity of the core of the reactor, and enhance the safety of the operation of the reactor.

[0039] The first end plug 4 is arranged at the bottom of the sleeve 2, and the connecting piece 31 is connected between the first end plug 4 and the sleeve 2, so that the buffer part is stably assembled with the sleeve 2, the first end plug 4 can effectively limit the position of the moderator rod 1, and the collision between the moderator rod 1 and other components during the operation or falling of the control rod is avoided, and the structural safety of the moderator rod 1 is further ensured. The limiting effect of the first end plug 4 can ensure that the moderator rod 1 is always in the preset working position in the sleeve 2, so that the moderator rod 1 can stably compensate the reactivity of the core, ensure the effective improvement of the value of the control rod, strengthen the stability of the connection between the buffer part and the sleeve 2, further protect the moderator rod 1, reduce the possibility of damage of the brittle moderator rod 1 due to displacement or collision, and further improve the operation reliability of the control rod as a whole, ensure the control effect of the control rod on the reactivity of the core of the reactor, and enhance the safety of the operation of the reactor.

[0040] The first end plug 4 is arranged at the bottom of the sleeve 2, and the connecting piece 31 is connected between the first end plug 4 and the sleeve 2, so that the buffer part is stably assembled with the sleeve 2, the first end plug 4 can effectively limit the position of the moderator rod 1, and the collision between the moderator rod 1 and other components during the operation or falling of the control rod is avoided, and the structural safety of the moderator rod 1 is further ensured. The limiting effect of the first end plug 4 can ensure that the moderator rod 1 is always in the preset working position in the sleeve 2, so that the moderator rod 1 can stably compensate the reactivity of the core, ensure the effective improvement of the value of the control rod, strengthen the stability of the connection between the buffer part and the sleeve 2, further protect the moderator rod 1, reduce the possibility of damage of the brittle moderator rod 1 due to displacement or collision, and further improve the operation reliability of the control rod as a whole, ensure the control effect of the control rod on the reactivity of the core of the reactor, and enhance the safety of the operation of the reactor.

[0041] The upper part of the first end plug 4 is sleeved in the lower part of the sleeve pipe 2, and the upper part of the connecting piece 31 is sleeved in the lower part of the first end plug 4. Both the first end plug 4 and the connecting piece 31 are hollow cylindrical structures, and the elastic piece 32 passes through the central parts of the first end plug 4 and the connecting piece 31 upwards and abuts against the bottom of the moderator rod 1.

[0042] The inner circumferential wall of the first end plug 4 is provided with a limiting protrusion radially inward, and the top of the connecting piece 31 abuts against the limiting protrusion, so that the limiting protrusion limits the connecting piece 31 in the vertical upward direction.

[0043] The connecting piece 31 is threadedly connected with the first end plug 4, the first end plug 4 is provided with a fixing pin radially, and the fixing pin abuts against the outer circumferential wall of the connecting piece 31, thereby further improving the connecting strength between the first end plug 4 and the connecting piece 31.

[0044] The material of the fixing pin is zirconium alloy material, and the sleeve pipe 2 and the end plug are also made of zirconium alloy material, which is beneficial to reducing neutron absorption and improving the value of the control rod.

[0045] The fixing pin is a screw, and the fixing pin is threadedly connected with the first end plug 4.

[0046] The bottom of the mounting groove 311 is provided with a liquid passing hole 312 which penetrates the bottom of the mounting groove 311 in the axial direction of the control rod.

[0047] The liquid passing hole 312 which penetrates in the axial direction of the control rod is arranged at the bottom of the mounting groove 311, which can provide a stable flow channel for the coolant and ensure that the coolant can flow smoothly through the area of the mounting groove 311. On the one hand, the effective flow of the coolant can timely take away the heat generated during the operation of the control rod, avoid the influence of local high temperature on the performance of the elastic piece 32, the connecting piece 31 and other components, ensure the stable operation of the buffer structure, and prolong its service life; on the other hand, the flow of the coolant can balance the pressure inside and outside the mounting groove 311, prevent the deformation or sealing failure of the components due to the pressure difference, and further improve the reliability of the overall structure of the control rod. At the same time, the stable heat exchange environment can also indirectly protect the brittle moderator rod 1, avoid the stress damage caused by temperature fluctuation, ensure the moderator rod 1 to continuously play the role of compensating the reactor reactivity and improving the value of the control rod, and further ensure the control effect of the control rod on the reactor reactivity and enhance the safety and stability of the reactor operation.

[0048] The liquid passing hole 312 is arranged at the middle part of the bottom of the mounting groove 311, and the liquid passing hole 312, the mounting groove 311 and the connecting piece 31 are coaxially arranged.

[0049] The first end plug 4 and the connecting piece 31 are both hollow cylindrical structures, and the space where the moderator rod 1 is located is connected with the space below through the liquid passing hole 312.

[0050] The follower 7 comprises a lower joint 51, and the connecting piece 31 is sleeved with the lower joint 51 away from one end of the moderator rod 1.

[0051] The connecting piece 31 is welded with the lower joint 51 to ensure good connection strength.

[0052] The follower 7 comprises a second end plug, the second end plug is sleeved with the sleeve 2, and the second end plug is located at the top of the sleeve 2 to form a limit for the moderator rod 1. The follower 7 comprises an upper joint 52, the upper joint 52 is threadedly connected with the top of the second end plug, and a fixing pin is radially arranged on the second end plug and abuts against the outer peripheral wall of the upper joint 52.

[0053] By arranging the second end plug and sleeving the second end plug with the top of the sleeve 2, the moderator rod 1 can be limited from the top of the sleeve 2, and the moderator rod 1 is bidirectionally positioned in cooperation with the first end plug 4 located at the bottom of the sleeve 2, so that axial movement of the moderator rod 1 is effectively avoided when the control rod is operated, dropped or affected by vibration, and damage caused by collision of the moderator rod 1 with the inner wall of the sleeve 2 or other components is prevented, and the structural integrity of the brittle moderator rod 1 is further ensured.

[0054] The upper joint 52 is threadedly connected with the top of the second end plug, which is convenient for assembly and subsequent maintenance of components of the control rod and can realize stable connection of the upper joint 52 and the follower 7, and the fixing pin radially arranged on the second end plug abuts against the outer peripheral wall of the upper joint 52, so that the locking effect of the fixing pin can prevent loosening of the threaded connection under long-term operation or impact working conditions, and the connection failure of the upper joint 52 and the second end plug can be avoided to prevent the structural stability of the control rod from being reduced.

[0055] The bottom of the second end plug is located in the sleeve 2, and the bottom of the second end plug abuts against the top of the moderator rod 1 to limit the moderator rod 1 in the vertical direction.

[0056] The material of the fixing pin is zirconium alloy material. The material of the second end plug is also zirconium alloy material, which is beneficial to reducing neutron absorption and improving the value of the control rod.

[0057] The fixing pin is a screw, and the fixing pin is threadedly connected with the second end plug.

[0058] The control rod comprises an absorption section 6, a follower 7 and a connecting piece 31 of a driving mechanism, and the absorption section 6, the follower 7 and the connecting piece 31 of the driving mechanism are sequentially and detachably connected in the axial direction of the control rod.

[0059] By setting the control rod to be detachably connected in sequence along the axis of the absorption section 6, the follower 7 and the driving mechanism connector 31, the assembly flexibility and maintenance convenience of the control rod are improved. In the production and assembly stage, each functional section can be processed and then combined, reducing the overall manufacturing difficulty. In subsequent use or maintenance, if a functional section fails, the entire control rod does not need to be replaced, only the corresponding fault section needs to be disassembled for maintenance or replacement, significantly reducing maintenance cost and downtime. The independent structure of each functional section can optimize the material and structure according to different functional requirements. For example, the absorption section 6 can use high-efficiency neutron absorption materials to ensure the core function of reactivity control, the follower 7 can focus on the protection and reactivity compensation design of the moderator rod 1, and the driving mechanism connector 31 can strengthen the adaptability and connection strength with the driving system, so that the performance of each component is more in line with its functional positioning, thereby improving the overall operation reliability of the control rod.

[0060] Among them, the upper joint 52 and the absorption section 6 are detachably connected, and the lower joint 51 and the connector 31 are detachably connected. That is, the absorption section 6, the follower section and the connector 31 can be individually disassembled. The absorption section 6, the follower section and the connector 31 can be threadedly connected, or can be detachably connected in other ways such as clamping.

[0061] Among them, the absorption section 6 adopts a silver-indium-chromium or boron carbide core tube, which is packaged in a stainless steel cladding to absorb neutrons.

[0062] Among them, the absorption section 6 is connected to the follower section below, and the follower section adopts neutron moderator materials such as metallic beryllium, beryllium oxide, yttrium hydride, and zirconium hydride, which are packaged in a zirconium alloy cladding. When the control rod falls, the follower section exits the core and the absorption section 6 enters the core, and the neutrons are changed from being moderated to being absorbed, thereby increasing the total value of the control rod and improving the core reactivity control capability.

[0063] As a person skilled in the art would readily understand, the above advantageous modes can be freely combined and superimposed without conflict.

[0064] The above is only a preferred embodiment of the present application and does not limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above is only a preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, which should be considered as the protection scope of the present application.

Claims

1. A control rod having a moderator rod follower, characterized by, The follower (7) comprises a moderator rod (1), a sleeve (2) sleeved on the moderator rod (1), and a buffer connected with the sleeve (2) and arranged at the bottom of the moderator rod (1) to apply an elastic force upward to the moderator rod (1).

2. The control rod of claim 1, wherein The buffer comprises a connecting piece (31) connected with the sleeve (2) and an elastic piece (32) arranged in the connecting piece (31) and abutting against the bottom of the moderator rod (1).

3. The control rod of claim 2, wherein The elastic piece (32) comprises a spring, the connecting piece (31) is provided with a mounting groove (311), and the spring is arranged in the mounting groove (311).

4. The control rod of claim 2, wherein The follower (7) further comprises a first end plug (4), the connecting piece (31) is connected with the sleeve (2) through the first end plug (4), and the first end plug (4) is arranged at the bottom of the sleeve (2) to limit the moderator rod (1).

5. The control rod of claim 4, wherein The first end plug (4) is sleeved in the sleeve (2) near one end of the moderator rod (1), the connecting piece (31) is sleeved in the first end plug (4) near one end of the moderator rod (1), and the elastic piece (32) abuts against the bottom of the moderator rod (1) through the first end plug (4).

6. The control rod of claim 5, wherein The connecting piece (31) is threadedly connected with the first end plug (4), a fixing pin is arranged in the first end plug (4) in the radial direction, and the fixing pin abuts against the outer peripheral wall of the connecting piece (31).

7. The control rod of claim 3, wherein A liquid passing hole (312) is arranged at the groove bottom of the mounting groove (311) and penetrates the groove bottom of the mounting groove (311) in the axial direction of the control rod.

8. The control rod of claim 2, wherein The follower (7) comprises a lower joint (51), and one end of the connecting piece (31) away from the moderator rod (1) is sleeved with the lower joint (51).

9. The control rod of claim 1, wherein The follower (7) comprises a second end plug sleeved with the sleeve (2) and arranged at the top of the sleeve (2) to limit the moderator rod (1). The follower (7) comprises an upper joint (52) threadedly connected with the top of the second end plug, a fixing pin is arranged in the second end plug in the radial direction, and the fixing pin abuts against the outer peripheral wall of the upper joint (52).

10. The control rod of claim 1, wherein The control rod comprises an absorbing section (6) and a driving mechanism connecting piece (31), and the absorbing section (6), the follower (7) and the driving mechanism connecting piece (31) are sequentially and detachably connected in the axial direction of the control rod.

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