Cross control rod assembly and reactor core arrangement structure

Abstract

The utility model provides a crisscross control rod subassembly and reactor core arrangement structure, crisscross control rod subassembly includes central body, cladding plate, boron carbide rod and cobalt rod, cladding plate is crisscross distributed around central body, its interior has the accommodation space, the boron carbide rod and cobalt rod are arranged in cladding plate, and the cladding plate is equipped with the accommodation space. The cobalt rods are arranged in the two adjacent cladding plates and are symmetrically distributed, the boron carbide rods in the control rod assembly are used for efficiently absorbing neutrons so as to control reactor reaction, and meanwhile, the cobalt rods absorb part of neutrons in the peripheral area of a reactor core to perform cobalt-60 radioactive isotope production, so that additional economic value is realized; the cross-shaped control rod assembly is arranged in the peripheral area of the reactor core, has small influence on the total reactivity of the reactor core, and is gradually lifted out in the later period of circulation, so that the utilization of nuclear fuel of the reactor core is not influenced, and the overall economical efficiency of the reactor is ensured; the arrangement of the cobalt rods and the arrangement of the cross-shaped control rod assembly in the reactor core can be flexibly designed according to different control requirements and production requirements.

Description

Technical Field

[0001] This utility model belongs to the field of nuclear power plant reactor fuel and related components, specifically relating to a cross-shaped control rod assembly and core arrangement structure. Background Technology

[0002] Control rod assemblies primarily consist of neutron-absorbing materials and other structural materials, serving to compensate for excess reactivity in the reactor core and regulate power in light water reactors. When fully inserted into the reactor core, the control rods absorb a large number of neutrons to prevent chain fission reactions. By moving the control rods within the reactor core at different speeds, the reactor power level can be adjusted. While the neutron-absorbing materials used in pressurized water reactors and boiling water reactors differ, their basic function remains the same: to regulate reactivity and power levels according to reactor operating requirements.

[0003] The CANDU heavy water reactor is the world's main facility for cobalt-60 isotope production. It primarily utilizes the similarity between cobalt-59's neutron absorption capacity and that of the original stainless steel (iron element) to replace the reactor's original stainless steel control rod assemblies with a corresponding number of cobalt control rods. Because these cobalt control rods are inserted into the reactor core in place of the original control rods, they incur additional core reactivity penalties, thus affecting the utilization efficiency of the core nuclear fuel. Furthermore, due to its special structural design for heavy water reactors, it is necessary to strictly ensure that the cobalt control rods and the original stainless steel control rods have very similar neutron absorption capacities, thus limiting the design flexibility of this type of cobalt control rod and preventing its application to other types of reactors. Cross-shaped control rods are widely used in boiling water reactors and certain types of natural circulation heated reactors for core reactivity and power distribution control and regulation, providing basic safety and control functions. However, their function is limited and cannot generate additional economic value. Considering their long-term insertion into the core and absorption of neutrons, they could be used to produce cobalt-60 isotope radioactive sources, thereby exploring new applications for natural circulation heated reactors, realizing additional economic value, and improving the economics of reactor construction. Utility Model Content

[0004] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a cross-shaped control rod assembly and core arrangement structure. By utilizing the integrated design of boron carbide rods and cobalt rods in the cross-shaped control rod assembly, as well as the flexible loading arrangement of cobalt rods, combined with the arrangement of the cross-shaped control rod assembly in the reactor, the cobalt-60 isotope production can be achieved without affecting the energy output of the nuclear fuel assembly. Its design is flexible and can be used in various boiling water reactors or heated reactors with cascaded fuel.

[0005] To achieve the above and other related objectives, this utility model provides a cross-shaped control rod assembly, comprising:

[0006] Central body;

[0007] A plurality of covering plates are uniformly arranged along the circumference of the central body, and the plurality of covering plates are symmetrically distributed in a cross shape, with each covering plate having an accommodating space inside;

[0008] An absorber rod is disposed in the receiving space of the covering plate, and at least a portion of the absorber rods in the receiving space formed by at least two adjacent covering plates are cobalt rods.

[0009] In an optional embodiment of this utility model, the plurality of covering plates arranged circumferentially along the central body are sequentially a first covering plate, a second covering plate, a third covering plate, and a fourth covering plate, and the absorber rods in the first covering plate and the second covering plate are all boron carbide rods.

[0010] In an optional embodiment of this utility model, the absorber rods in the third and fourth coating plates are both cobalt rods.

[0011] In an optional embodiment of this utility model, the absorber rods in the third and fourth coating plates are cobalt rods and boron carbide rods, which are arranged in a direction away from the central body, and the arrangement positions of the cobalt rods in the third and fourth coating plates are consistent.

[0012] In an optional embodiment of this utility model, the cobalt rod comprises:

[0013] Encasing;

[0014] A cobalt core block is disposed within the casing;

[0015] End plugs are disposed at both ends of the casing to close the inner cavity of the casing;

[0016] An elastic element is disposed between the cobalt core block and the end of the casing to fix the cobalt core block.

[0017] This utility model also proposes a core arrangement structure, including:

[0018] Fuel rod assemblies, with multiple fuel rod assemblies arranged symmetrically in a checkerboard pattern in the reactor core;

[0019] A control rod assembly, wherein the control rod assembly is a cross-shaped control rod assembly that is inserted between four adjacent fuel rod assemblies, the control rod assembly includes a first control rod assembly and a second control rod assembly, wherein the first control rod assembly is a boron carbide control rod assembly;

[0020] The second control rod assembly includes:

[0021] Central body;

[0022] A plurality of covering plates are uniformly arranged along the circumference of the central body, and the plurality of covering plates are symmetrically distributed in a cross shape, with each covering plate having an accommodating space inside;

[0023] An absorber rod is disposed in the receiving space of the covering plate, and at least a portion of the absorber rods in the receiving space formed by at least two adjacent covering plates are cobalt rods.

[0024] In an optional embodiment of this utility model, in the second control rod assembly, the plurality of cladding plates arranged circumferentially along the central body are sequentially a first cladding plate, a second cladding plate, a third cladding plate, and a fourth cladding plate. The third cladding plate and the fourth cladding plate are located in the region near the periphery of the core, and the absorber rods in the third cladding plate and the fourth cladding plate are all cobalt rods.

[0025] In an optional embodiment of this utility model, the absorber rods in the third and fourth covering plates are cobalt rods and boron carbide rods, the cobalt rods and the boron carbide rods are arranged in a direction away from the central body, and the arrangement positions of the cobalt rods in the third and fourth covering plates are consistent.

[0026] In an optional embodiment of this utility model, the boron carbide rod is arranged at one end near the central body within the third and fourth covering plates.

[0027] In an optional embodiment of the present invention, the second control rod assembly is gradually removed from the reactor core at the end of the fuel cycle.

[0028] The technical advantage of this invention lies in the fact that by replacing some of the boron carbide rods in the cross-shaped control rod assembly with cobalt rods, it is possible to produce cobalt-60 isotopes by neutron absorption in the reactor, thereby realizing additional economic value for the reactor. Through the flexible design of the cobalt rod arrangement in the control rod assembly, combined with the arrangement of the cross-shaped control rod assembly in the reactor, it is ensured that while realizing additional economic value, it will not affect the energy output of the nuclear fuel assembly. It is applicable to various boiling water reactors or heated reactors that use boxed fuel assemblies, and its structural design is flexible and has a wide range of applications. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the cross-shaped control rod assembly in one embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the cross-shaped control rod assembly in another embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the cobalt rod in a cross-shaped control rod assembly according to one embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the fourth quadrant region of the core arrangement structure in one embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of the structure of the first control rod assembly in the core arrangement structure of one embodiment of the present invention.

[0035] Label Explanation:

[0036] 100, Central body; 200, Coating plate; 300, Boron carbide rod; 400, Cobalt rod;

[0037] 210. First covering plate; 220. Second covering plate; 230. Third covering plate; 240. Fourth covering plate;

[0038] 410. Shell; 420. Cobalt core block; 430. Elastic element; 440. Upper plug; 450. Lower plug;

[0039] 1. Fuel rod assembly; 2. First control rod assembly; 3. Second control rod assembly. Detailed Implementation

[0040] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0041] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0042] Natural circulation heating reactors are an important form of clean energy. To improve the economic efficiency of building such reactors, it is necessary to explore their applications as much as possible. Among these applications, the production of cobalt-60 isotopes is a method worth promoting. Cross-shaped control rods are widely used in the core reactivity and power distribution control and regulation of boiling water reactors and certain types of natural circulation heating reactors. They have basic safety and control functions. Their long-term insertion into the core and absorption of neutrons can be used to produce cobalt-60 isotope radioactive sources, thereby realizing additional economic value.

[0043] Please see Figures 1 to 3 This invention provides a cross-shaped control rod assembly, including a central body 100, cladding plates 200, and absorber rods. The central body 100 serves as a support column located at the center of the control rod assembly. Multiple cladding plates 200 are uniformly arranged along the circumference of the central body 100, and the multiple cladding plates 200 are symmetrically distributed in a cross shape. Each cladding plate 200 has an internal receiving space, and the absorber rods are disposed within the receiving spaces of the cladding plates 200. The absorber rods have both reactivity control and isotope production capabilities. They include absorber rods that easily absorb neutrons to regulate the reactor, such as boron carbide rods 300, and cobalt rods 400 that can achieve isotope production when absorbing neutrons. At least a portion of the absorber rods within the receiving spaces formed by at least two adjacent cladding plates 200 are cobalt rods 400. When the cross-shaped control rod assembly is inserted into the reactor, the boron carbide rods 300 can effectively absorb neutrons to regulate the core reaction, while the cobalt rods 400 can absorb some neutrons to produce cobalt-60 radioactive isotopes. By rationally arranging the cobalt rods 400 and boron carbide rods 300, cobalt-60 radioisotope production can be carried out without affecting the reactor's control functions, thereby realizing its additional economic value.

[0044] Please see Figures 1 to 3In an optional embodiment of this utility model, the central body 100 can be, for example, a cylinder, and four covering plates 200 are evenly distributed around the circumference of the central body 100, namely, the first covering plate 210, the second covering plate 220, the third covering plate 230 and the fourth covering plate 240. The cross section of the covering plate 200 can be, for example, a U-shaped structure, with its open end connected to the central body 100. Each covering plate 200 is provided with an absorber rod, which is evenly arranged in the covering plate 200 along the cross direction. The absorber rod includes boron carbide rods 300 and cobalt rods 400. The boron carbide rods 300 and cobalt rods 400 are integrated in the cross-shaped control rod assembly in combination with production needs and reactor control requirements. Specifically, for example, the absorber rods in the first cladding plate 210 and the second cladding plate 220 are both boron carbide rods 300, and the absorber rods in the third cladding plate 230 and the fourth cladding plate 240 are both cobalt rods 400. When the control rod assembly is inserted into the reactor, the first cladding plate 210 and the second cladding plate 220 are located in the region close to the reactor core, and the core reaction is regulated by absorbing neutrons through the boron carbide rods 300 inside them. The third cladding plate 230 and the fourth cladding plate 240 are located in the region close to the periphery of the reactor core, and the cobalt rods 400 are used to absorb neutrons to achieve the production of cobalt-60 radioactive isotopes. The impact on the core reaction is reduced by the reasonable arrangement of the absorber rods.

[0045] Please see Figures 1 to 3 In another optional embodiment of this utility model, the absorber rods in the third cladding plate 230 and the fourth cladding plate 240 are boron carbide rods 300 and cobalt rods 400. The cobalt rods 400 and boron carbide rods 300 are arranged in a direction away from the central body 100, and the arrangement positions of the cobalt rods 400 in the third cladding plate 230 and the fourth cladding plate 240 are consistent. For example, the boron carbide rods 300 can be arranged at one end close to the central body 100, and the cobalt rods 400 can be arranged at one end away from the central body 100. The boron carbide rods 300 in the third cladding plate 230 and the fourth cladding plate 240 can also absorb some neutrons for core conditioning in the area near the periphery of the core. Of course, in other embodiments, the arrangement of boron carbide rods 300 and cobalt rods 400 can be configured in various ways. For example, the boron carbide rods 300 and cobalt rods 400 within the cladding plate 200 can be arranged alternately, or cobalt rods 400 can be arranged within multiple cladding plates 200. The principle for arranging the absorber rods is to ensure that there are sufficient boron carbide rods 300 for controlling the core reaction and cobalt rods 400 for production within the cladding plate 200, and that the boron carbide rods 300 and cobalt rods 400 are arranged in the same position on each cladding plate 200, so that the core structure can be kept uniform and stable after the control rod assembly is inserted into the core. It should be noted that the number and arrangement of boron carbide rods 300 and cobalt rods 400 within each cladding plate 200 need to be determined in conjunction with the needs of reactor control and the production requirements of the isotope radiation source.

[0046] Please see Figures 1 to 3 In an optional embodiment of this utility model, the cobalt rod 400 includes a shell 410, a cobalt core 420, end plugs, and an elastic element 430. The shell 410 is located on the periphery of the cobalt rod 400, forming an accommodating space inside. The cobalt core 420 and the elastic element 430 are disposed inside the shell 410. The end plugs include an upper end plug 440 and a lower end plug 450, which are respectively disposed at both ends of the shell 410 to close the inner cavity of the shell 410. The elastic element 430 is disposed between the ends of the cobalt core 420 and the shell 410 to fix the cobalt core 420. The elastic element 430 can be, for example, a compression spring, which is disposed at one end of the cobalt core 420 and presses the cobalt core 420 to fix it. It is understood that the cobalt rod 400 has a similar structure to the boron carbide rod 300, and it replaces part of the boron carbide rod 300 in the original control rod assembly, which can ensure isotope production without affecting reactor control. When the cross-shaped control rod assembly is inserted into the reactor, the boron carbide rods 300 and cobalt rods 400 within the absorber rods absorb excess neutrons. This achieves core conditioning while simultaneously producing the radioactive isotope cobalt-60, fully utilizing the reactor to realize additional economic value. The arrangement of the boron carbide rods 300 and cobalt rods 400 is rationally designed according to reactor control requirements, ensuring no impact on reactor functionality. The cobalt core block 420 uses a cobalt metal block. After the cobalt rods 400 absorb sufficient neutrons, a reaction occurs, producing the radioactive isotope cobalt-60. The main neutron reaction formula is as follows:

[0047]

[0048] Please see Figures 1 to 5 This utility model also proposes a reactor core arrangement structure, including fuel rod assemblies 1 and control rod assemblies. The fuel rod assembly 1 is box-shaped, and multiple fuel rods for nuclear fission reactions are arranged inside the box. Multiple fuel rod assemblies 1 are symmetrically and evenly arranged in a checkerboard pattern in the reactor core. The control rod assembly is a cross-shaped control rod assembly, which is inserted between four adjacent fuel rod assemblies 1 and distributed in various areas of the reactor core for adjusting reactor power or shutting down the reactor.

[0049] Please see Figures 1 to 5In an optional embodiment of this utility model, the control rod assembly includes a first control rod assembly 2 and a second control rod assembly 3. The second control rod assembly 3 includes a central body 100, a covering plate 200, and an absorber rod. A plurality of covering plates 200 are uniformly arranged along the circumference of the central body 100. The plurality of covering plates 200 are symmetrically distributed in a cross shape. Each covering plate 200 has a receiving space inside. The absorber rod is disposed in the receiving space of the covering plate 200. At least a portion of the absorber rod in the receiving space formed by at least two adjacent covering plates 200 is a cobalt rod 400. Specifically, for example, the plurality of covering plates 200 arranged along the circumference of the central body 100 are sequentially a first covering plate 210, a second covering plate 220, a third covering plate 230, and a fourth covering plate 240. The absorber rod includes a boron carbide rod 300 and a cobalt rod 400. The first control rod assembly 2 is a boron carbide control rod assembly, and its overall structure is similar to that of the second control rod assembly 3. The internal absorber rods are all boron carbide rods 300. The first control rod assembly 2 is mainly used to achieve the regulation of the core reactor, while the second control rod assembly 3 is mainly used to achieve the production of radioactive isotopes.

[0050] Please see Figures 1 to 5 In an optional embodiment of this utility model, the first control rod assembly 2 is disposed in a region close to the interior of the reactor core, and the second control rod assembly 3 is disposed in a region close to the periphery of the reactor core, so that its influence on the reactivity of the reactor core is almost negligible; and the second control rod assembly 3 is gradually removed from the reactor core at the end of the fuel cycle, thereby ensuring that the utilization of the reactor core nuclear fuel is not affected by the cobalt rod 400.

[0051] Please see Figures 1 to 5 In an optional embodiment of this utility model, in the second control rod assembly 3, the absorber rods in the first cladding plate 210 and the second cladding plate 220 are both boron carbide rods 300, located in the region close to the reactor core. The third cladding plate 230 and the fourth cladding plate 240 are located in the region close to the periphery of the reactor core. The absorber rods in the third cladding plate 230 and the fourth cladding plate 240 are both cobalt rods 400. The first cladding plate 210 and the second cladding plate 220, together with the boron carbide rods 300 in the other first control rod assembly 2, are used to control the reactor core reaction. The cobalt rods 400 in the third cladding plate 230 and the fourth cladding plate 240 absorb neutrons in the outer region to react and produce radioactive isotopes, thereby making full use of the reactor.

[0052] Please see Figures 1 to 5In another optional embodiment of this utility model, the absorber rods in the third cladding plate 230 and the fourth cladding plate 240 are boron carbide rods 300 and cobalt rods 400. The boron carbide rods 300 are arranged at one end near the center body 100, which is close to the core center region, and the cobalt rods 400 are arranged at the other end. Through this arrangement, the third cladding plate 230 and the fourth cladding plate 240 can also control the reactor reaction to a certain extent in the region near the periphery.

[0053] Please see Figures 1 to 5 In one specific embodiment of this invention, for example, the second control rod assembly 3 can be arranged at position 8 of the reactor core, close to the core but not located within it. This ensures sufficient neutron absorption to generate the cobalt-60 radioactive isotope, and numerical simulations show that this design has a negligible impact on the overall reactivity of the reactor core. Through this reactor core design, rod 8 will be slowly withdrawn from the core at the end of the fuel cycle, thus ensuring that the utilization of the core nuclear fuel is not affected by the control rods and guaranteeing the energy output of the nuclear fuel assembly. It should be noted that, since the reactor core has a symmetrical structure, it can be divided into four quadrant regions. The fuel rod assembly 1 and control rod assembly in each region have symmetrical and consistent structures, ensuring the uniformity and stability of the overall reactor core structure. Specifically, for example, in this embodiment, the third cladding plate 230 and the fourth cladding plate 240 of the second control rod assembly 3 in the fourth quadrant are located to the right and below position 8, respectively. The corresponding third cladding plate 230 and the fourth cladding plate 240 of the second control rod assembly 3 in the first quadrant are located to the left and above position 8, respectively, to ensure that the third cladding plate 230 and the fourth cladding plate 240 are located in the region close to the outer periphery of the reactor core.

[0054] Please see Figures 1 to 5 It should be noted that in other embodiments, the second control rod assembly 3 can also be located at other positions in the reactor core, such as positions 1 to 7 in the figure. When the cobalt rod 400 is close to the core, it can provide a stronger neutron flux, thereby further improving the production capacity of the cobalt-60 isotope radioactive source. In this case, the structure of the second control rod assembly 3 and the reactor core needs to be specifically designed under the premise of ensuring the overall reactivity control capability and other safety limits of the reactor core, so as to meet the production needs while realizing the core reaction control.

[0055] In summary, the cross-shaped control rod assembly of this invention replaces some of the boron carbide rods 300 with cobalt rods 400 on the basis of the original control rod assembly. Its structure and position within the reactor are rationally designed in an integrated manner according to reactor control requirements. While achieving reactor regulation, it fully utilizes the reactor for the production of cobalt-60 radioactive isotopes. Furthermore, improvements to the material and arrangement of the absorber rods and the core arrangement structure of the cross-shaped control rod assembly allow it to be applied to the production of other isotopes, maximizing its additional economic value while ensuring reactor safety control. By slowly removing the cross-shaped control rod assembly from the core in the later stages of the reaction cycle, the utilization of the core nuclear fuel is ensured to be unaffected by the control rods, thus guaranteeing the overall nuclear fuel economy of the reactor. The loading arrangement of the cobalt rods 400 in the cross-shaped control rod assembly and the core structure arrangement can be flexibly designed according to production needs and reactor control requirements, making it applicable to various boiling water reactors or heated reactors using cascaded fuel assemblies.

[0056] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

[0057] Throughout this description, numerous specific details, such as examples of components and / or methods, are provided to provide a complete understanding of embodiments of the present invention. However, those skilled in the art will recognize that embodiments of the present invention may be practiced without one or more of these specific details or by other devices, systems, components, methods, parts, materials, components, etc. In other instances, well-known structures, materials, or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of the present invention.

[0058] Throughout this specification, references to "an embodiment," "an embodiment," or "a specific embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention, but not necessarily in all embodiments. Therefore, the various representations of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout the specification do not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic of any specific embodiment of the present invention can be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments of the present invention described and illustrated herein may be based on the teachings herein and will be considered part of the spirit and scope of the present invention.

[0059] It should also be understood that one or more of the elements shown in the figures may be implemented in a more separate or more integrated manner, or may even be removed because they are inoperable in certain circumstances or provided because they may be useful for a particular application.

[0060] Furthermore, unless otherwise expressly stated, any arrows in the accompanying drawings should be considered illustrative only and not limiting. Additionally, unless otherwise stated, the term "or" as used herein is generally intended to mean "and / or". Where a term is anticipated to provide a separation or combination capability that is unclear, a combination of components or steps will also be considered as indicated.

[0061] As used herein and throughout the claims below, unless otherwise specified, “a” and “the” include the plural references. Similarly, as used herein and throughout the claims below, unless otherwise specified, “in” means “in” and “on”.

[0062] The above description of the embodiments shown in this utility model (including the content set forth in the abstract of the specification) is not intended to be an exhaustive enumeration or to limit the utility model to the precise forms disclosed herein. Although specific embodiments and examples of the utility model have been described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the utility model, as will be recognized and understood by those skilled in the art. As indicated, these modifications can be made to the utility model in accordance with the above description of the embodiments described herein, and such modifications will be within the spirit and scope of the utility model.

[0063] This document has generally described the systems and methods in detail to aid in understanding the present invention. Furthermore, various specific details have been set forth to provide a general understanding of embodiments of the present invention. However, those skilled in the art will recognize that embodiments of the present invention can be practiced without one or more specific details, or using other devices, systems, accessories, methods, components, materials, parts, etc. In other instances, well-known structures, materials, and / or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of the present invention.

[0064] Therefore, although the present invention has been described herein with reference to specific embodiments thereof, freedom of modification, various changes and substitutions are also within the scope of the above disclosure, and it should be understood that in some cases, certain features of the present invention may be adopted without departing from the scope and spirit of the invention and without corresponding use of other features. Thus, many modifications can be made to adapt a particular environment or material to the essential scope and spirit of the present invention. The present invention is not intended to be limited to the specific terms used in the following claims and / or the specific embodiments disclosed as the best mode of carrying out the present invention, but the present invention will include any and all embodiments and equivalents falling within the scope of the appended claims. Therefore, the scope of the present invention will be determined only by the appended claims.

Claims

1. A cross-shaped control rod assembly, characterized in that, include: Central body; A plurality of covering plates are uniformly arranged along the circumference of the central body, and the plurality of covering plates are symmetrically distributed in a cross shape, with each covering plate having an accommodating space inside; An absorber rod is disposed in the receiving space of the covering plate, and at least a portion of the absorber rods in the receiving space formed by at least two adjacent covering plates are cobalt rods.

2. The cross-shaped control rod assembly according to claim 1, characterized in that, The multiple cladding plates arranged circumferentially along the central body are, in sequence, a first cladding plate, a second cladding plate, a third cladding plate, and a fourth cladding plate. The absorber rods inside the first cladding plate and the second cladding plate are all boron carbide rods.

3. The cross-shaped control rod assembly according to claim 2, characterized in that, The absorber rods within the third and fourth coating plates are both cobalt rods.

4. The cross-shaped control rod assembly according to claim 2, characterized in that, The absorber rods within the third and fourth cladding plates are cobalt rods and boron carbide rods, which are arranged in a direction away from the central body, and the cobalt rods are arranged in the same corresponding positions within the third and fourth cladding plates.

5. The cross-shaped control rod assembly according to claim 1, characterized in that, The cobalt rod comprises: Encasing; A cobalt core block is disposed within the casing; End plugs are disposed at both ends of the casing to close the inner cavity of the casing; An elastic element is disposed between the cobalt core block and the end of the casing to fix the cobalt core block.

6. A core arrangement structure, characterized in that, include: Fuel rod assemblies, with multiple fuel rod assemblies arranged symmetrically in a checkerboard pattern in the reactor core; A control rod assembly, wherein the control rod assembly is a cross-shaped control rod assembly that is inserted between four adjacent fuel rod assemblies, the control rod assembly includes a first control rod assembly and a second control rod assembly, wherein the first control rod assembly is a boron carbide control rod assembly; The second control rod assembly includes: Central body; A plurality of covering plates are uniformly arranged along the circumference of the central body, and the plurality of covering plates are symmetrically distributed in a cross shape, with each covering plate having an accommodating space inside; An absorber rod is disposed in the receiving space of the covering plate, and at least a portion of the absorber rods in the receiving space formed by at least two adjacent covering plates are cobalt rods.

7. The core arrangement structure according to claim 6, characterized in that, In the second control rod assembly, the plurality of cladding plates arranged circumferentially along the central body are, in sequence, a first cladding plate, a second cladding plate, a third cladding plate, and a fourth cladding plate. The third cladding plate and the fourth cladding plate are located in the region near the periphery of the core, and the absorber rods within the third cladding plate and the fourth cladding plate are all cobalt rods.

8. The core arrangement structure according to claim 7, characterized in that, The absorber rods within the third and fourth cladding plates are cobalt rods and boron carbide rods, which are arranged in a direction away from the central body, and the cobalt rods are arranged in the same corresponding positions within the third and fourth cladding plates.

9. The core arrangement structure according to claim 7, characterized in that, Within the third and fourth cladding plates, boron carbide rods are arranged at one end near the central body.

10. The core arrangement structure according to claim 6, characterized in that, The second control rod assembly is gradually removed from the core at the end of the fuel cycle.

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