Fuel assembly for reactor, fuel unit and reactor core

Abstract

The invention discloses a fuel assembly for a reactor, a fuel unit and a reactor core, and particularly relates to the technical field of nuclear reactors. The plurality of fuel rods are arranged in the assembly shell; a plurality of control assemblies, wherein the control assemblies are installed in the assembly shell; the control assembly and the fuel rod are cylindrical, and the fuel rod and the control assembly are arranged and distributed in the assembly shell together; the fuel unit comprises a plurality of fuel assemblies; the reactor core comprises a plurality of fuel units. In order to solve the technical problems of poor reactor control capability and poor reactor miniaturization design of a control rod in the prior art, the invention provides the reactor core structure which is good in nuclear reaction control capability and small in reactor volume.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear reaction, and in particular to a fuel assembly, a fuel unit and a reactor core for a reactor. Background Art

[0002] Small nuclear reactors have a wide range of uses, such as steam supply for industrial parks, power supply for data centers, power supply for islands, seawater desalination or cogeneration, and are a hot topic in current research and application.

[0003] Small reactors are usually cooled by liquid metal, and boric acid solution cannot be added to liquid metal. Therefore, the soluble boron control system commonly used in large pressurized water reactor nuclear power plants cannot be used for reactivity control. In order to simplify the system and achieve compact layout, control rods are usually used for reactivity control. Long refueling cycle is an important indicator of small reactors, but long refueling cycle requires the reactor to have sufficient backup reactivity, and more reactivity needs to be controlled by control rods, which puts higher requirements on reactivity control capability. Due to the compact layout of small reactor cores and the small size of fuel assemblies, the space and number of control rods and drive mechanisms are limited. Therefore, improving the reactivity control capability of small reactors is a key technical problem that needs to be solved in the design of small reactor cores.

[0004] See also Figure 7In the existing small reactor core design, in order to improve the control ability of the control rod, a design scheme of thickening the diameter of the control rod is usually set in each fuel assembly to control the nuclear reactor. However, due to the spatial self-screening effect of the neutron absorbing material of the control rod, the neutron absorption capacity does not increase significantly after the diameter of the control rod is increased, and the thickening of the control rod will occupy more fuel rod positions, resulting in a larger core size, which is not conducive to the miniaturization of the core design. At the same time, the use of thick control rods will lead to different nuclear reaction rates at different positions of the reactor. The power near the control rod is low, and the power far away from the control rod is high, resulting in uneven distribution of reactor power, affecting the safety and economy of the reactor. In addition, the increase in the amount of control rod material used will not be fully consumed at the end of its life, which will cause a large reactivity penalty, reduce the core refueling cycle, reduce fuel utilization, and reduce economy. At the same time, thick control rods will also occupy the position of fuel rods per unit area and reduce the number of fuel rods per unit area, which is extremely unfavorable to the core design of small reactors. At the same time, in the prior art, the value of control rods is increased by thickening control rods. There is a drive rod and a drive mechanism above each control rod. Each control rod occupies the position of multiple fuel rods. In order to maintain the total number of core fuel rods unchanged, the number of fuel assemblies needs to be increased, resulting in a larger core size. The size of a small reactor fuel assembly is usually small, and the control rod drive mechanism is usually limited by the size of the motor and cannot be miniaturized. When the size of the motor is larger than the size of the fuel assembly, two adjacent control rod drive mechanisms will interfere. In order to arrange so many control rod drive mechanisms, it is necessary to increase the size of the fuel assembly, resulting in the core cannot be completely miniaturized. Thick control rods have strong control capabilities and can absorb more neutrons, making the probability of nuclear reactions in the fuel rods around the control rods smaller, while the probability of nuclear reactions in the fuel rods far away from the control rods is higher, resulting in uneven heat from each fuel rod in the core, distortion of the core power distribution, and affecting the safety of the reactor. A larger number of control rod drive mechanisms will increase equipment costs and affect the economic efficiency of the reactor. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problems in the prior art that the control rod has poor control capability over the reactor and the reactor miniaturization design is poor. The present invention provides the following technical solutions:

[0006] A fuel assembly for a reactor, comprising: an assembly shell;

[0007] a plurality of fuel rods, wherein the fuel rods are installed inside the assembly housing;

[0008] A plurality of control components are installed inside the component housing.

[0009] The control assembly and the fuel rod are cylindrical, and the fuel rod and the control assembly are arranged together inside the assembly shell, and each arranged control assembly occupies an arrangement position of the fuel rod.

[0010] Preferably, the control components are symmetrically distributed inside the component housing.

[0011] A fuel unit for a reactor comprises a plurality of the above-mentioned fuel assemblies and a lifting mechanism, wherein all the fuel assemblies are arranged in an array, the lifting mechanism is arranged above the fuel assembly array, and the lifting mechanism is fixedly connected to each control assembly to drive the control assembly to penetrate into / leave the interior of the assembly shell.

[0012] The lifting mechanism includes a driving rod and several connecting rods radially distributed along the driving rod. One end of each connecting rod is fixedly connected to the upper end of the control component, and the other end is fixedly connected to the lower end of the driving rod. The driving motor and the driving rod cooperate with each other to make the connecting rod move up and down.

[0013] The control assembly includes a control rod and a guide cylinder, one end of each guide cylinder is installed in the assembly housing, and the other end extends to the outside of the assembly housing, the control rod is arranged inside the guide cylinder and slides in the guide cylinder, and the upper end of the control rod is fixedly connected to one end of the connecting rod.

[0014] The cross section of the guide cylinder located inside the component housing is a circular ring, and the portion located outside the component housing is provided with a through slit; the connecting rod passes through the through slit and is fixedly connected to the upper end of the control rod.

[0015] It also includes an upper head and a lower head, which are relatively installed at the two ends of the component shell, and cooperate with each other to fix the fuel rod and the guide cylinder, and the guide cylinder passes through the upper head and is fixedly connected to the upper head.

[0016] Preferably, there are four fuel assemblies, and there are three control assemblies in each fuel assembly. The cross-section of each fuel assembly is square, and the four fuel assemblies are distributed in a square matrix.

[0017] Preferably, there are six fuel assemblies, and there are three control assemblies in each fuel assembly. The cross-section of each fuel assembly is a regular hexagon. The six fuel assemblies are adjacent to each other and distributed in an annular matrix. A second fuel assembly is provided in the middle of the annular array. The second fuel assembly includes a second assembly shell and several second fuel rods installed inside the second assembly shell. All fuel rods are arranged in an array.

[0018] A reactor core comprises several of the above-mentioned fuel units.

[0019] The present invention has the following advantages:

[0020] (1) The present invention provides a fuel assembly for a small reactor. Compared with the prior art in which each control assembly contains a thick control rod, the present invention arranges and distributes the number of control assemblies and the number of fuel rods into a whole, and each control assembly occupies the arrangement position of a fuel rod. The shell of each fuel assembly is optimally utilized, the number of fuel rods per unit area is increased, and the volume of the core is reduced as a whole, achieving the purpose of designing a small reactor; and this design arranges the control rods in a dispersed manner, improves the control ability of the fuel rods, and makes the design of the reactor have the same nuclear reaction efficiency, but the number of fuel rods placed per unit area is greater, and the nuclear reaction efficiency and reaction control ability are better.

[0021] (2) The driving mechanism designed in the present invention, through the design of the lifting mechanism, enables one driving motor to control the lifting of all control components in a fuel unit. Compared with the prior art that each control component needs to be driven and controlled by one driving motor, this design realizes that one driving motor controls multiple control components across fuel assemblies, reduces the number of driving motors to be set, and solves the problem that the existing small reactor has limited space and cannot arrange a sufficient number of driving mechanisms. At the same time, this design, when combined with multiple control rods, not only further reduces the reactor space, but also overcomes the problem that a large number of control rods correspond to a large number of driving motors.

[0022] (3) In the fuel unit provided by the present invention, the control rod can not only control the fuel rod of the control assembly where the control rod is located, but also control the nuclear reaction of the adjacent fuel rods across the fuel assembly. By arranging each control rod across the fuel assembly, the core power distribution can be flattened, thereby improving the safety of the reactor.

[0023] (4) The present invention improves the control capability of the reactor, which is beneficial to extending the reactor refueling cycle and further improving the economic efficiency of the reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the fuel assembly

[0025] Figure 2 This is a schematic diagram of the fuel unit of Example 1;

[0026] Figure 3 Schematic diagram of fuel unit in Example 2

[0027] Figure 4 It is a top view of the lifting mechanism;

[0028] Figure 5 It is a schematic diagram of the lifting mechanism structure;

[0029] Figure 6 It is a schematic diagram of the top view of the structure of the guide tube and the lifting mechanism;

[0030] Figure 7 Schematic diagram of a fuel assembly in the prior art.

[0031] In the figure: 1. assembly shell, 2. fuel rod, 3. control assembly, 31. control rod, 32. guide cylinder, 33. through slot, 4. lifting mechanism, 41. driving rod, 42. connecting rod, 5. second fuel assembly, 6. fuel assembly. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0033] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents some embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features and technical solutions in the embodiments may be combined with each other.

[0035] It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further defined and explained in the subsequent figures. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "upper", "lower", etc. is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the product of the invention is usually placed when in use, or the orientation or position relationship commonly understood by those skilled in the art. Such terms are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0036] Embodiment 1:

[0037] See also Figure 1 , Figure 2 , Figures 4 to 7A fuel assembly 6 for a reactor comprises: an assembly shell 1, a plurality of fuel rods 2, wherein the fuel rods 2 are installed inside the assembly shell 1; a plurality of control assemblies 3, wherein the control assemblies 3 are installed inside the assembly shell 1; the control assemblies 3 and the fuel rods 2 are cylindrical, and the ratio of the diameter of the fuel rods 2 to the outer diameter of the control assemblies 3 is 1:(0.8-1.2), and the fuel rods 2 and the control assemblies 3 are arranged together and distributed inside the assembly shell 1, and each arranged control assembly 3 occupies an arrangement position of the fuel rods 2. The assembly shell 1 is used to hold the fuel rods 2 and the control assemblies 3, the fuel rods 2 are used to perform nuclear reactions, and the control assemblies 3 are used to control the rate of the nuclear reactions. When the control assembly 3 and the fuel rods 2 are arranged and distributed, one control assembly 3 occupies the arrangement position of one fuel rod 2, which makes the interior of the assembly shell 1 achieve the best utilization rate, thereby increasing the number of fuel rods 2 set per unit area, and then reducing the volume of the core as a whole, achieving the purpose of designing a small reactor; and, this design arranges the control rods 31 in a dispersed manner, improves the control ability of the fuel rods 2, so that the design of the reactor has the same nuclear reaction efficiency, the number of fuel rods 2 placed per unit area is greater, and the nuclear reaction efficiency and reaction control ability are better.

[0038] The control components 3 are symmetrically distributed inside the component housing 1. The symmetrically distributed control components 3 can control the nuclear reaction rate of the entire control component 3 more uniformly.

[0039] A fuel unit for a reactor includes a plurality of the above-mentioned fuel assemblies 6 and a lifting mechanism 4, all of the fuel assemblies 6 are arranged in an array, the lifting mechanism 4 is arranged above the array of the fuel assemblies 6, and the lifting mechanism 4 is fixedly connected to each control assembly 3, and is used to drive the control assembly 3 to penetrate into / leave the interior of the assembly shell 1. The lifting mechanism 4 is used to control the control assembly 3 to move along the extension direction of the fuel rod 2. When the lifting mechanism 4 drives the control assembly 3 to gradually extend into the interior of the assembly shell 1, the control assembly 3 controls the nuclear reaction of the fuel rod 2 inside the assembly shell 1. The deeper the control assembly 3 extends into the assembly shell 1, the higher the degree of control over the nuclear reaction; when the lifting mechanism 4 drives the control assembly 3 to gradually leave the interior of the assembly shell 1, the control assembly 3 controls and reduces the nuclear reaction of the fuel rod 2 inside the assembly shell 1 until the control assembly 3 completely leaves the assembly shell 1, and the control assembly 3 no longer controls the reaction speed of the nuclear reaction.

[0040] In the above technical solution, all fuel assemblies 6 of a fuel unit share the same lifting mechanism 4, that is, all control assemblies 3 are controlled by the lifting mechanism 4, which saves the number of lifting mechanisms 4 occupied. In the existing technology center, the value of the control rods 31 is improved by adopting a thickened control rod 31. There is a drive rod 41 and a drive mechanism above each control rod 31. Each control rod 31 occupies the position of multiple fuel rods 2. In order to maintain the total number of core fuel rods 2 unchanged, it is necessary to increase the number of fuel assemblies 6, resulting in a larger core size. In the above technical solution, one lifting mechanism 4 controls the control assembly 3 of one fuel unit, saving the number of lifting mechanisms 4. Combined with the multi-position distribution of the control assembly 3, it not only improves the control efficiency of the nuclear reaction, but also further saves the volume of the core, and overcomes the problem that the number of control rods 31 is large, and the corresponding number of drive motors is large and difficult to set.

[0041] The lifting mechanism 4 includes a driving rod 41 and a plurality of connecting rods 42 radially distributed along the driving rod 41, one end of each connecting rod 42 is fixedly connected to one end of the control assembly 3, and the other end is fixedly connected to the driving rod 41, and the driving motor and the driving rod 41 cooperate with each other to make the connecting rod 42 move up and down. In one embodiment, the output end of the driving motor is connected to a connecting piece with an internal thread, and the driving rod 41 is provided with an external thread, and the connecting piece is threadedly connected to the driving rod 41. In one embodiment, a ball screw connection structure or a gear rack connection structure can also be used between the driving motor and the driving rod 41.

[0042] The control assembly 3 includes a control rod 31 and a guide cylinder 32, one end of each guide cylinder 32 is installed in the assembly housing 1, and the other end extends to the outside of the assembly housing 1, the control rod 31 is arranged inside the guide cylinder 32 and slides in the guide cylinder 32, and the upper end of the control rod 31 is fixedly connected to one end of the connecting rod 42. The guide cylinder 32 plays a limiting role when the control rod 31 moves up and down in the assembly housing 1.

[0043] The cross section of the portion of the guide cylinder 32 located inside the assembly housing 1 is a circular ring, and the portion located outside the assembly housing 1 is provided with a through slit 33, which makes the cross section of the portion of the guide cylinder 32 outside the assembly housing 1 C-shaped; the connecting rod 42 passes through the through slit 33 and is fixedly connected to the upper end of the control rod 31. The portion of the guide cylinder 32 inside the assembly housing 1 is a cylinder, and the portion outside the assembly housing 1 is a C-shaped ring. The connecting rod 42 passes through the through slit 33 and is fixedly connected to the upper end of the control rod 31, which can save upper space to the maximum extent.

[0044] It also includes an upper head and a lower head, which are relatively mounted at the two ends of the component shell 1, and are both provided with a fixing structure adapted to the fuel rod 2 or the control component 3. The upper head and the lower head cooperate with each other to fix the fuel rod 2 and the guide tube 32, and the guide tube 32 passes through the upper head and is fixedly connected to the upper head.

[0045] There are four fuel assemblies 6, and there are three control assemblies 3 in each fuel assembly 6. The three control assemblies 3 are symmetrically distributed in the fuel assembly 6. The cross-section of each fuel assembly 6 is square, and the four fuel assemblies 6 are distributed in a square matrix.

[0046] The above technical solution has the following beneficial effects: the square assembly arrangement is adopted, the assembly shape is simple, the processing is easy, the assembly is convenient, the coolant share is large, and the distribution is more uniform, which helps to improve the cooling efficiency. The control rod 31 is arranged near the local hot spot, which can reduce the hot spot factor while performing reactivity control, prevent accidents in the reactor, and improve the safety of the reactor.

[0047] A reactor core includes a plurality of fuel units. The reactor core disclosed in this solution optimizes the control assembly 3 in the fuel assembly 6 and optimizes the lifting mechanism 4 in the fuel unit, so that the reactor core has the smallest volume under the same design index.

[0048] Embodiment 2:

[0049] See also Figure 1 , Figures 3 to 6A fuel assembly 6 for a reactor comprises: an assembly shell 1, a plurality of fuel rods 2, wherein the fuel rods 2 are installed inside the assembly shell 1; a plurality of control assemblies 3, wherein the control assemblies 3 are installed inside the assembly shell 1; the control assemblies 3 and the fuel rods 2 are cylindrical, and the ratio of the diameter of the fuel rods 2 to the outer diameter of the control assemblies 3 is 1:(0.8-1.2), and the fuel rods 2 and the control assemblies 3 are arranged together and distributed inside the assembly shell 1, and each arranged control assembly 3 occupies an arrangement position of the fuel rods 2. The assembly shell 1 is used to hold the fuel rods 2 and the control assemblies 3, the fuel rods 2 are used to perform nuclear reactions, and the control assemblies 3 are used to control the rate of the nuclear reactions. When the control assembly 3 and the fuel rods 2 are arranged and distributed, one control assembly 3 occupies the arrangement position of one fuel rod 2, which makes the interior of the assembly shell 1 achieve the best utilization rate, thereby increasing the number of fuel rods 2 set per unit area, and then reducing the volume of the core as a whole, achieving the purpose of designing a small reactor; and, this design arranges the control rods 31 in a dispersed manner, improves the control ability of the fuel rods 2, so that the design of the reactor has the same nuclear reaction efficiency, the number of fuel rods 2 placed per unit area is greater, and the nuclear reaction efficiency and reaction control ability are better.

[0050] The control components 3 are symmetrically distributed inside the component housing 1. The symmetrically distributed control components 3 can control the nuclear reaction rate of the entire control component 3 more uniformly.

[0051] A fuel unit for a reactor includes a plurality of the above-mentioned fuel assemblies 6 and a lifting mechanism 4, all of the fuel assemblies 6 are arranged in an array, the lifting mechanism 4 is arranged above the fuel assemblies 6, and the lifting mechanism 4 is fixedly connected to each control assembly 3, and is used to drive the control assembly 3 to penetrate into or leave the assembly shell 1. The lifting mechanism 4 is used to control the control assembly 3 to move along the extension direction of the fuel rod 2. When the lifting mechanism 4 drives the control assembly 3 to gradually extend into the assembly shell 1, the control assembly 3 controls the nuclear reaction of the fuel rod 2 inside the assembly shell 1. The deeper the control assembly 3 extends into the assembly shell 1, the higher the degree of control of the nuclear reaction; when the lifting mechanism 4 drives the control assembly 3 to gradually leave the assembly shell 1, the control assembly 3 controls and reduces the nuclear reaction of the fuel rod 2 inside the assembly shell 1 until the control assembly 3 completely leaves the assembly shell 1, and the control assembly 3 no longer controls the reaction speed of the nuclear reaction.

[0052] In the above technical solution, all fuel assemblies 6 of a fuel unit share the same lifting mechanism 4, that is, all control assemblies 3 are controlled by the lifting mechanism 4, which saves the number of lifting mechanisms 4 occupied. In the existing technology center, the value of the control rods 31 is improved by adopting a thickened control rod 31. There is a drive rod 41 and a drive mechanism above each control rod 31. Each control rod 31 occupies the position of multiple fuel rods 2. In order to maintain the total number of core fuel rods 2 unchanged, it is necessary to increase the number of fuel assemblies 6, resulting in a larger core size. In the above technical solution, one lifting mechanism 4 controls the control assembly 3 of one fuel unit, saving the number of lifting mechanisms 4. Combined with the multi-position distribution of the control assembly 3, it not only improves the control efficiency of the nuclear reaction, but also further saves the volume of the core, and overcomes the problem that the number of control rods 31 is large, and the corresponding number of drive motors is large and difficult to set.

[0053] The lifting mechanism 4 includes a driving rod 41 and a plurality of connecting rods 42 radially distributed along the driving rod 41, one end of each connecting rod 42 is fixedly connected to one end of the control assembly 3, and the other end is fixedly connected to the driving rod 41, and the driving motor and the driving rod 41 cooperate with each other to make the connecting rod 42 move up and down. In one embodiment, the output end of the driving motor is connected to a connecting piece with an internal thread, and the driving rod 41 is provided with an external thread, and the connecting piece is threadedly connected to the driving rod 41. In one embodiment, a ball screw connection structure or a gear rack connection structure can be used between the driving motor and the driving rod 41.

[0054] The control assembly 3 includes a control rod 31 and a guide cylinder 32, one end of each guide cylinder 32 is installed in the assembly housing 1, and the other end extends to the outside of the assembly housing 1, the control rod 31 is arranged inside the guide cylinder 32 and slides in the guide cylinder 32, and the upper end of the control rod 31 is fixedly connected to one end of the connecting rod 42. The guide cylinder 32 plays a limiting role when the control rod 31 moves up and down in the assembly housing 1.

[0055] The cross section of the portion of the guide cylinder 32 located inside the assembly housing 1 is a circular ring, and the portion located outside the assembly housing 1 is provided with a through slit 33, which makes the cross section of the portion of the guide cylinder 32 outside the assembly housing 1 C-shaped; the connecting rod 42 passes through the through slit 33 and is fixedly connected to the upper end of the control rod 31. The portion of the guide cylinder 32 inside the assembly housing 1 is a cylinder, and the portion outside the assembly housing 1 is a C-shaped ring. The connecting rod 42 passes through the through slit 33 and is fixedly connected to the upper end of the control rod 31, which can save upper space to the maximum extent.

[0056] It also includes an upper head and a lower head, which are relatively mounted at the two ends of the component shell 1, and are both provided with a fixing structure adapted to the fuel rod 2 or the control component 3. The upper head and the lower head cooperate with each other to fix the fuel rod 2 and the guide tube (32), and the guide tube 32 passes through the upper head and is fixedly connected to the upper head.

[0057] There are six fuel assemblies 6, and there are three control assemblies 3 in each fuel assembly 6. The cross section of each fuel assembly 6 is a regular hexagon. The six fuel assemblies 6 are adjacent to each other and are distributed in a ring matrix. A second fuel assembly 5 is arranged in the middle of the ring array. The second fuel assembly 5 includes a second assembly shell and a plurality of second fuel rods 51 installed inside the second assembly shell. All fuel rods 2 are arranged in an array. Three control assemblies 3 are arranged at intervals in the middle of the regular hexagonal assembly shell 1. Two adjacent fuel assemblies 6 are close to the adjacent edges, and two control assemblies 3 located in different fuel assemblies 6 are close.

[0058] The beneficial effects of the above technical solution are as follows: the regular hexagonal component arrangement is adopted, the layout is compact, more fuel rods 2 can be arranged in a limited space, and the control components 3 are evenly arranged in the fuel assembly 6 array, which can flatten the reactor power, reduce the radial power peak factor, help to evenly distribute heat, reduce the risk of local overheating, and improve the safety and economy of the reactor.

[0059] A reactor core includes a plurality of fuel units. The reactor core disclosed in this solution optimizes the control assembly 3 in the fuel assembly 6 and optimizes the lifting mechanism 4 in the fuel unit, so that the reactor core has the smallest volume under the same design index.

[0060] The working principle of the present invention is: the driving motor controls the driving rod 41 to move up and down, and the driving rod 41 drives the connecting rod 42 to move up and down. Because the connecting rod 42 is fixedly connected to the control rod 31, it drives the control rod 31 to move up and down. When the reactor core fuel rod 2 undergoes a nuclear fusion reaction, the control rod 31 gradually moves from the outside of the assembly shell 1 to the inside of the assembly shell 1 along the guide tube under the action of the driving motor according to actual needs to control the nuclear reaction. According to the degree of the nuclear reaction, the driving motor controls the length of the control rod 31 extending into the assembly shell 1.

[0061] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A fuel assembly (6) for a reactor, characterized in that: include: Component housing (1); A plurality of fuel rods (2), wherein the fuel rods (2) are installed inside the assembly housing (1); A plurality of control components (3), wherein the control components (3) are installed inside the component housing (1); The fuel rods (2) and the control assembly (3) are cylindrical in shape. The fuel rods (2) and the control assembly (3) are arranged and distributed together inside the assembly shell (1), and any one of the control assemblies (3) occupies an arrangement position of the fuel rods (2).

2. A reactor fuel assembly (6) according to claim 1, characterized in that: The control components (3) are symmetrically distributed inside the component housing (1).

3. A fuel unit for a reactor, characterized in that: It comprises several fuel assemblies (6) and lifting mechanisms (4) as described in claim 1, wherein the fuel assemblies (6) are arranged in an array, and the lifting mechanism (4) is arranged above the fuel assembly (6) array, and the lifting mechanism (4) is fixedly connected to each control assembly (3) and is used to drive the control assembly (3) to penetrate into / leave the interior of the assembly shell (1).

4. A fuel unit for a reactor as claimed in claim 3, characterized in that: The lifting mechanism (4) comprises a driving rod (41) and a plurality of connecting rods (42) radially distributed along the driving rod (41), one end of each connecting rod (42) being fixedly connected to the upper end of the control assembly (3), and the other end being fixedly connected to the lower end of the driving rod (41), and the driving motor and the driving rod (41) cooperate with each other to enable the connecting rod (42) to move up and down.

5. A fuel unit for a reactor as claimed in claim 4, characterized in that: The control assembly (3) comprises a control rod (31) and a guide cylinder (32), one end of each guide cylinder (32) is installed in the assembly housing (1), and the other end extends to the outside of the assembly housing (1), the control rod (31) is arranged inside the guide cylinder (32) and slides in the guide cylinder (32), and the upper end of the control rod (31) is fixedly connected to one end of a connecting rod (42).

6. A fuel unit for a reactor as claimed in claim 5, characterized in that: The cross section of the portion of the guide cylinder (32) located inside the component housing (1) is a circular ring, and the portion located outside the component housing (1) is provided with a through slit (33); the connecting rod (42) passes through the through slit (33) and is fixedly connected to the upper end of the control rod (31).

7. A fuel unit for a reactor as claimed in claim 6, characterized in that: It also includes an upper head and a lower head, the upper head and the lower head are relatively mounted at the two ends of the assembly shell (1), the upper head and the lower head cooperate with each other to fix the fuel rod (2) and the guide cylinder (32), and the guide cylinder (32) passes through the upper head and is fixedly connected to the upper head.

8. A fuel unit for a reactor as claimed in claim 3, characterized in that: There are four fuel assemblies (6), each of which contains three control assemblies (3), and each of which has a square cross-section. The four fuel assemblies (6) are distributed in a square matrix.

9. A fuel unit for a reactor as claimed in claim 3, characterized in that: There are six fuel assemblies (6), and there are three control assemblies (3) in each of the fuel assemblies (6). The cross section of each fuel assembly (6) is a regular hexagon. The six fuel assemblies (6) are adjacent to each other and are distributed in a ring matrix. A second fuel assembly (5) is provided in the middle of the ring array. The second fuel assembly (5) includes a second assembly shell and a plurality of second fuel rods (51) installed inside the second assembly shell. All the fuel rods (2) are arranged in an array.

10. A reactor core, characterized in that: Comprising several fuel units according to claim 8 or 9.

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