Heat pipe microstack core and method of arranging same

Abstract

The application provides a heat pipe micro stack core and a method for arranging the same. The core comprises a plurality of regular hexagonal fuel assemblies, the fuel assemblies comprising at least three types, namely, a first type of fuel assembly in which a heat pipe is arranged in a central hole, a second type of fuel assembly in which a fuel rod is arranged in a central hole, and a third type of fuel assembly, and the arrangement rule is that, for the first type of fuel assembly, 3 second type of fuel assemblies are arranged at 120° intervals in the 6 fuel assembly arrangement positions adjacent to the first type of fuel assembly, and the remaining 3 positions are arranged with the third type of fuel assemblies; and the fuel rods and the heat pipes are arranged at the hole level according to the following rules: 6 adjacent holes are arranged at 60° intervals around each hole; for the hole in which the fuel rod is arranged, 3 holes arranged at 120° intervals among the 6 holes adjacent to the hole are arranged with the heat pipes, and the remaining 3 holes are arranged with the fuel rods; and for the hole in which the heat pipe is arranged, the 6 holes adjacent to the hole are all arranged with the fuel rods. The application ensures that each fuel rod is adjacent to at least three heat pipes.

Description

Technical Field

[0001] This application relates primarily to the field of nuclear reactor technology, and in particular to a heat pipe microreactor core and its arrangement method. Background Technology

[0002] Heat pipe microreactors, as a novel type of reactor, typically employ an all-solid-state core design. Their core region mainly consists of fuel rods, a substrate, heat pipes, a thermoelectric / thermodynamic conversion system, and a waste heat removal system. Heat is primarily removed through heat conduction in the fuel rods and substrate, as well as phase change heat transfer within the heat pipes.

[0003] While heat pipe reactors can efficiently remove heat along the axial direction by utilizing the long-distance heat conduction capability of heat pipes, heat transfer in the direction perpendicular to the heat pipes (core radial direction) mainly relies on the solid thermal conductivity of the core matrix. Compared to pressurized water reactors and other reactor types that can achieve efficient heat transfer through radial coolant flow, solid cores have weaker radial heat transfer capabilities, and the radial temperature non-uniformity effect is more significant.

[0004] In this context, if there are areas in the reactor core where fuel rods accumulate locally, and adjacent heat pipes fail, the heat from the fuel rods in those areas will be difficult to dissipate, which could easily lead to excessively high local temperatures and affect reactor safety. Summary of the Invention

[0005] The technical problem to be solved by this application is to provide a heat pipe micropile core and its arrangement method to solve the redundancy problem of radial heat dissipation path of the heat pipe micropile core.

[0006] To address the aforementioned technical problems, this application provides a heat pipe microreactor core, comprising: multiple hexagonal fuel assemblies, the fuel assemblies including at least three types: a first type of fuel assembly with a heat pipe inserted in the center hole, a second type of fuel assembly with a fuel rod inserted in the center hole, and a third type of fuel assembly. The third type of fuel assembly is obtained by rotating the second type of fuel assembly by 60°. The first, second, and third types of fuel assemblies are arranged in a honeycomb pattern in the core, and the arrangement rule is: for every six fuel assemblies adjacent to a first type of fuel assembly, there are three second type fuel assemblies spaced 120° apart. The remaining three positions are where the third type of fuel assembly is arranged; wherein, the base of each fuel assembly has multiple holes arranged in an equilateral triangular grid, and fuel rods or heat pipes are inserted into the holes. The fuel rods and heat pipes are arranged at the hole level according to the following rules: each hole is surrounded by 6 adjacent holes at 60° intervals; for the hole where a fuel rod is inserted, among the 6 adjacent holes, 3 holes at 120° intervals are used to insert heat pipes, and the remaining 3 holes are used to insert fuel rods; for the hole where a heat pipe is inserted, all 6 adjacent holes are used to insert fuel rods; wherein each fuel rod in the entire core is surrounded by at least three heat pipes adjacent to it.

[0007] Optionally, it further includes: a first combustible poison assembly, which is formed by replacing the fuel rods in the hexagonal corner region with combustible poison rods in the second type of fuel assembly; and a second combustible poison assembly, which is formed by replacing the fuel rods in the hexagonal corner region with combustible poison rods in the third type of fuel assembly.

[0008] Optionally, among the six fuel assemblies adjacent to the first combustible poison assembly, there are three of the third type of fuel assemblies spaced 120° apart; among the six fuel assemblies adjacent to the second combustible poison assembly, there are three of the second type of fuel assemblies spaced 120° apart.

[0009] Optionally, the reactor core includes an inner fuel region and an outer fuel region, wherein the fuel rods in the inner fuel region use low-enrichment fuel and the fuel rods in the outer fuel region use high-enrichment fuel.

[0010] Optionally, it also includes a reactivity control system comprising multiple drums arranged around the core, each drum having an absorber on one side and a reflective material on the other side.

[0011] Optionally, the drum includes a plurality of first-size drums arranged at six notch locations around the core periphery.

[0012] Optionally, the drum further includes a plurality of second-size drums, the second-size drums being smaller than the first-size drums, and the second-size drums being arranged in pairs and interspersed between adjacent first-size drums.

[0013] Optionally, it also includes at least one stop rod assembly arranged among multiple fuel assemblies.

[0014] Optionally, the ratio of fuel rods to heat pipes in the reactor core is approximately 2:1.

[0015] To address the aforementioned technical problems, this application provides a method for arranging the core of a heat pipe micropile, comprising the following steps:

[0016] At least three types of regular hexagonal fuel assemblies are provided: a first type of fuel assembly with a heat pipe inserted in the central hole, a second type of fuel assembly with a fuel rod inserted in the central hole, and a third type of fuel assembly. The third type of fuel assembly is obtained by rotating the second type of fuel assembly by 60°. Each fuel assembly has multiple holes arranged in an equilateral triangular grid on its base. Fuel rods or heat pipes are inserted into the holes. The fuel rods and heat pipes are arranged at the hole level according to the following rules: each hole is surrounded by 6 adjacent holes at 60° intervals; for a hole with a fuel rod inserted, 3 of the 6 adjacent holes are filled with heat pipes at 120° intervals, and the remaining 3 holes are filled with fuel rods; for a hole with a heat pipe inserted, all 6 adjacent holes are filled with fuel rods.

[0017] The first type of fuel assembly, the second type of fuel assembly, and the third type of fuel assembly are arranged as follows: three of the six fuel assembly positions adjacent to the first type of fuel assembly are the second type of fuel assemblies spaced 120° apart, and the third type of fuel assemblies are arranged in the remaining three positions, so that each fuel rod in the entire core area has at least three heat pipes adjacent to it.

[0018] Compared with the prior art, this application has the following advantages:

[0019] The heat pipe microreactor core and its arrangement method of this application, through the arrangement of different types of fuel assemblies and the coordinated arrangement of heat pipes and fuel rod pore positions, ensure that each fuel rod has at least three heat pipes around it for highly redundant cooling. The failure of a single heat pipe does not affect safety, significantly improving the safety of the core. By arranging three heat pipes at 120° intervals around the fuel rods and arranging fuel rods around all the heat pipes, the phenomenon of adjacent heat pipes is fundamentally eliminated, avoiding local hot spots. Attached Figure Description

[0020] The accompanying drawings are included to provide a further understanding of this application. They are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of this application.

[0021] Figure 1 This is a schematic diagram of the structure of a heat pipe microreactor core based on a 19-hole fuel assembly according to an embodiment of this application.

[0022] Figure 2 This is a schematic diagram of the structure of a first type of fuel assembly according to an embodiment of this application.

[0023] Figure 3 This is a schematic diagram of the structure of a second type of fuel assembly according to an embodiment of this application.

[0024] Figure 4This is a schematic diagram of the structure of a third type of fuel assembly according to an embodiment of this application.

[0025] Figure 5 yes Figure 1 A schematic diagram showing the arrangement of different fuel component types.

[0026] Figure 6 This is a schematic diagram of the arrangement of fuel assemblies in the reactor core according to an embodiment of this application.

[0027] Figure 7 This is a schematic diagram of the structure of a first combustible poison component according to an embodiment of this application.

[0028] Figure 8 This is a schematic diagram of the structure of a second combustible poison component according to an embodiment of this application.

[0029] Figure 9 This is a schematic diagram of the structure of a heat pipe microreactor core based on a 19-hole fuel assembly, according to another embodiment of this application.

[0030] Figure 10 This is a schematic diagram of the core structure of a heat pipe micropile according to another embodiment of this application.

[0031] Figure 11 This is a schematic diagram of the structure of a heat pipe microreactor core based on a 37-hole fuel assembly according to an embodiment of this application.

[0032] Figure 12 This is a schematic diagram of the structure of a heat pipe micropile core based on a staggered arrangement, according to an embodiment of this application.

[0033] Figure 13 This is a flowchart of a method for arranging the core of a heat pipe micropile according to an embodiment of this application.

[0034] Reference numerals: 1 Substrate; 2 Fuel rod; 3 Heat pipe; 4 Shutdown rod assembly; 5 Large drum; 51 First absorber; 52 First reflective material; 6 Outer casing; 7 Combustible poison rod; 8 Small drum; 81 Second absorber; 82 Second reflective material; 9 Enclosure;

[0035] A. Type I fuel assembly;

[0036] B1 Type II fuel assembly;

[0037] B2 Category III fuel assembly;

[0038] BP1 First Combustible Poison Assembly;

[0039] BP2 Second Combustible Poison Assembly;

[0040] D. Category IV fuel assembly;

[0041] E1 Category 5 fuel assembly;

[0042] E2 Category 6 fuel assembly;

[0043] R1 inner fuel zone;

[0044] R2 outer fuel zone;

[0045] T is an equilateral triangle. Detailed Implementation

[0046] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0047] Example 1: Heat pipe microreactor core based on 19-hole fuel assembly;

[0048] Figure 1 This is a schematic diagram of the core structure of a heat pipe micropile according to an embodiment of this application. Figure 1 As shown, the heat pipe microreactor core includes multiple hexagonal fuel assemblies. The fuel assembly substrate 1 has multiple apertures arranged in an equilateral triangular grid, and fuel rods 2 or heat pipes 3 are arranged within these apertures. The fuel rods 2 and heat pipes 3 are arranged according to the following rules:

[0049] Each fuel rod is surrounded by six adjacent fuel rods spaced 60° apart. For the fuel rod 2 fuel rod insertion point, three of the six adjacent fuel rod insertion points are spaced 120° apart and contain heat pipes, while the remaining three contain fuel rods. For the fuel rod 3 fuel rod insertion point, all six adjacent fuel rod insertion points contain fuel rods. Based on this arrangement, the fuel rod to heat pipe ratio in the reactor core is approximately 2:1, providing ample space for fissile material, and each fuel rod is surrounded by three heat pipes.

[0050] like Figure 1 As shown in the figure, in this embodiment, there are three main types of fuel assemblies arranged in the reactor core: Type I fuel assembly A, Type II fuel assembly B1, and Type III fuel assembly B2. The structure of Type I fuel assembly A is as follows: Figure 2 As shown, the first type of fuel assembly A includes a substrate 1 with 19 holes arranged in an equilateral triangular grid. A heat pipe 3 is placed in the central hole, and fuel rods 2 are inserted into the six adjacent holes. Fuel rods 2 are also inserted into the hexagonal corner areas, and the remaining holes are used to place heat pipes 3. The first type of fuel assembly A consists of 12 fuel rods and 7 heat pipes, ensuring that each side of the hexagonal assembly has a heat pipe, facilitating thermal connection with adjacent assemblies.

[0051] The structure of the second type of fuel assembly B1 is as follows: Figure 3 As shown, the second type of fuel assembly B1 includes a substrate 1 with 19 holes arranged in an equilateral triangular grid. A fuel rod 2 is placed in the central hole. Of the six adjacent holes, three are spaced 120° apart and contain heat pipes 3; the remaining three holes contain fuel rods 2. For each heat pipe 3 hole, six adjacent holes contain fuel rods 2. The structure of the third type of fuel assembly B2 is as follows... Figure 4 As shown, the third type of fuel assembly B2 is obtained by rotating the second type of fuel assembly B1 by 60°. Both the second type of fuel assembly B1 and the third type of fuel assembly B2 consist of 13 fuel rods and 6 heat pipes.

[0052] Figure 5 yes Figure 1 A schematic diagram showing the arrangement of different fuel component types. (See diagram below.) Figure 5 As shown, different types of fuel assemblies are arranged alternately in the reactor core. Type II fuel assemblies B1 and Type III fuel assemblies B2 are arranged alternately around Type I fuel assembly A, ensuring that heat pipes and fuel rods are staggered. Specifically, Type I fuel assembly A, Type II fuel assembly B1, and Type III fuel assembly B2 are arranged in a honeycomb pattern in the reactor core, with the following arrangement rule: For the six fuel assembly positions adjacent to Type I fuel assembly A, there are three Type II fuel assemblies B1 spaced 120° apart, and the remaining three positions are occupied by Type III fuel assemblies B2.

[0053] In this embodiment, the heat pipe microreactor core also includes a shutdown rod assembly 4 for emergency shutdown. Depending on design requirements, one, multiple, or no shutdown rod assembly 4 may be arranged.

[0054] Figure 6 This is a schematic diagram of the arrangement of fuel assemblies in the reactor core according to an embodiment of this application. Figure 6 As shown, this application ensures that a fuel rod 2 can be adjacent to three heat pipes 3 at any position through the coordinated arrangement at the component level and the orifice level, thereby guaranteeing the redundancy of the heat pipes. Even if some heat pipes fail, it can still ensure that the heat of the fuel rod can be carried away by other heat pipes, preventing the fuel rod temperature from becoming too high.

[0055] The fuel rods and heat pipes in this application are arranged in a staggered manner within the fuel assembly, ensuring that there are no adjacent heat pipes within the core, and that each fuel rod is surrounded by at least three heat pipes. The fuel assembly within the core consists of a fuel assembly with a fuel rod at its center and a fuel assembly with a heat pipe at its center, arranged in a staggered manner. This ensures effective cooling of the edge and corner regions, solving the problem of uneven edge distribution that exists with similar assembly arrangements, and avoiding imbalances in the distribution of heat pipes and fuel rods in edge and corner regions. Considering the arrangement of adjacent fuel assemblies, it ensures that each fuel rod in the entire core is surrounded by three heat pipes. While maximizing the utilization of core space for fuel rod arrangement, it also ensures heat pipe redundancy. Even if one heat pipe fails randomly at any location, the fuel rod can still rely on the other two adjacent heat pipes to remove heat, reducing the maximum temperature of the fuel rod after a local heat pipe failure and improving core safety.

[0056] To flatten the core power distribution and compensate for fuel consumption and extend core life as burnup deepens, this application also introduces combustible poison assemblies. The combustible poison assemblies include a first combustible poison assembly BP1 and a second combustible poison assembly BP2. For example... Figure 3 , Figure 7 and Figure 8 As shown, the first flammable poison assembly BP1 is constructed by replacing the fuel rods in the hexagonal corner regions of the second type of fuel assembly B1 with flammable poison rods 7. The second flammable poison assembly BP2 is constructed by replacing the fuel rods in the hexagonal corner regions of the third type of fuel assembly B2 with flammable poison rods 7.

[0057] like Figure 9 As shown, in areas requiring power flattening (such as the core center or specific locations), some Type II fuel assemblies B1 or Type III fuel assemblies B2 are replaced with corresponding Type I combustible poison assemblies BP1 or Type II combustible poison assemblies BP2. As seen in the figure: in the six fuel assembly positions adjacent to the Type I combustible poison assembly BP1, there are three Type III fuel assemblies B2 spaced 120° apart; in the six fuel assembly positions adjacent to the Type II combustible poison assembly BP2, there are three Type II fuel assemblies B1 spaced 120° apart. This arrangement ensures neutron absorption by the combustible poison assemblies in the early stages of core combustion, suppressing local power peaks and resulting in a more uniform power distribution. As burnup progresses, the combustible poison is gradually consumed, compensating for fuel consumption and extending core lifespan.

[0058] like Figure 1As shown, the heat pipe microreactor core also includes a reactivity control system, which comprises multiple large drums 5. A first absorber 51 is located on one side of each drum, and a first reflective material 52 is located on the other side. The neutron leakage rate of the core is controlled by rotating the large drums 5, thereby adjusting the reactivity. When the first absorber 51 faces the core, neutron absorption increases, reducing reactivity; when the first reflective material 52 faces the core, neutron leakage decreases, increasing reactivity. In this embodiment, the reactivity control system includes six large drums 5, which are arranged at six notch locations around the core.

[0059] In some embodiments, drum control is used as the primary reactive control method, and the shutdown rod assembly 4 can be selectively configured as a supplementary or backup control means. For example, when the large drum 5 fails or redundant shutdown capability is required, the shutdown rod assembly 4 can be quickly inserted into the reactor core to achieve emergency shutdown by absorbing neutrons.

[0060] To achieve more precise power regulation, some embodiments employ a control method combining large and small drums. For example... Figure 10 As shown, the heat pipe microreactor core also includes multiple small drums 8, which are arranged in pairs and interspersed between adjacent large drums 5. This embodiment employs a control method combining 6 large drums and 12 small drums to achieve more precise reactivity adjustment. The large drums 5 are arranged at the 6 notches in the honeycomb arrangement of the hexagonal components. Each large drum 5 has a first absorber 51 with an angle of 120° installed on one side and a first reflective material 52 on the other side. The large drums 5 serve as the primary reactivity control means, controlling neutron leakage through rotation to achieve coarse adjustment. The 12 small drums are arranged in pairs and interspersed in the gaps between the large drums. Each small drum 8 includes a second absorber 81 and a second reflective material 82, but is smaller in size than the large drums. The small drums 8 serve as an auxiliary control means, coordinating with the large drums 5 to achieve more precise power adjustment. Optionally, the large and small drums work together as follows: the large drums rotate synchronously, rapidly changing the core reactivity. The small drums can be adjusted independently or in groups to fine-tune the power distribution and compensate for local disturbances. This application uses a combination of large and small drums to achieve multi-level reactive control from coarse to fine adjustment.

[0061] To further flatten the radial power distribution, in some embodiments, such as Figure 10As shown, the reactor core includes an inner fuel region R1 and an outer fuel region R2. The inner fuel region R1 is located in the central region of the core and consists of several regular hexagonal fuel assemblies. Due to the high neutron flux in the inner fuel region, the fuel rods in the inner fuel region use low-enriched fuel to suppress power peaks. The outer fuel region R2 surrounds the inner fuel region R1 and consists of several regular hexagonal fuel assemblies. Due to the lower neutron flux in the outer fuel region, the fuel rods in the outer fuel region use high-enriched fuel to improve power output. This application achieves a more uniform radial power distribution in the reactor core through the partitioned configuration of fuel enrichment, thereby improving fuel utilization and core safety.

[0062] Optionally, the heat pipe microreactor core also includes a perimeter plate 9, arranged around the perimeter of the core. Specifically, the perimeter plate 9 is located between the fuel zone and the drum, and surrounds the entire fuel zone. The perimeter plate 9 provides support and fixation for the core and can reduce the transfer of heat from the core to external structural components to a certain extent.

[0063] Optionally, the heat pipe micropile core also includes an outer cylinder 6.

[0064] Example 2: Heat pipe microreactor core based on 37-hole fuel assembly;

[0065] This embodiment is basically the same as Embodiment 1, except that the fuel assembly uses a 37-hole design. Figure 11 As shown, the 37-hole assembly has a hole distribution of one hole in the center, six holes in the first ring, twelve holes in the second ring, and eighteen holes in the third ring. The 37-hole assembly implies greater core power and a more complex arrangement. To achieve a strictly staggered arrangement of heat pipes and fuel rods, this embodiment designs three types of 37-hole fuel assemblies:

[0066] Type 4 fuel assembly D: One heat pipe is placed in the central hole, and the remaining 36 holes are arranged in a staggered pattern, so that fuel rods and heat pipes alternate in an equilateral triangular grid, ultimately forming 24 fuel rods and 13 heat pipes. Due to the symmetry of the equilateral triangular arrangement, this arrangement ensures that each side of the hexagonal assembly has a heat pipe, facilitating thermal connection with adjacent assemblies.

[0067] Type 5 fuel assembly E1: One fuel rod is placed in the central hole, and the remaining 36 holes are arranged in a staggered pattern. This ultimately forms 25 fuel rods and 12 heat pipes.

[0068] The sixth type of fuel assembly E2 is obtained by rotating the fifth type of fuel assembly E1 by 60°. This rotational relationship allows the fifth type of fuel assembly E1 and the sixth type of fuel assembly E2 to be matched with different sides of the fourth type of fuel assembly D, achieving omnidirectional staggered engagement.

[0069] The various components within the fuel zone are arranged according to the following pattern: Around the fourth type of fuel assembly D, the fifth type of fuel assembly E1 and the sixth type of fuel assembly E2 are arranged alternately to ensure that no two heat pipes are directly adjacent throughout the entire core; each fuel rod has three heat pipes in adjacent positions. Specifically, this arrangement ensures that three heat pipes also exist around fuel rods in the core corners and edge regions, thus avoiding localized overheating due to insufficient cooling capacity in these areas; when a single heat pipe fails randomly at any location, the affected fuel rod can still rely on the remaining two heat pipes to dissipate heat, achieving high redundancy; the ratio of fuel rods to heat pipes in the entire core is approximately 2:1, verifying the scalability of this application. That is, by adjusting the number of openings in a single substrate and the number of fuel assemblies contained in the core, this application can be applied to heat pipe reactor cores of different sizes and power levels.

[0070] Furthermore, the core arrangement, combustible poison assemblies, fuel zoning, drum control, and shutdown rod configuration in Example 2 are the same as in Example 1, and will not be repeated here.

[0071] Because of the contact thermal resistance on the contact surfaces of adjacent components, heat exchange between the heat pipes and fuel rods between components can be affected. In some embodiments, efficient heat exchange can be achieved by filling with high-performance thermally conductive materials. The filling process and materials include, but are not limited to, metal powder filling, metal brazing, and inorganic thermally conductive adhesives.

[0072] like Figure 12 As shown, in some embodiments, the hexagonal components are arranged in a staggered manner, leaving an equilateral triangle T in the middle of every three hexagonal components. This staggered arrangement ensures that the six fuel rods around each heat pipe are arranged in a regular hexagonal pattern, and the heat transfer distance between each group of heat pipes and fuel rods remains consistent.

[0073] Example 3: Arrangement method of heat pipe micropile core;

[0074] This embodiment provides a method for arranging the core of a heat pipe micropile. For example... Figure 13 As shown, the arrangement method of the heat pipe micro stack core includes:

[0075] Step S131: Provide at least three types of regular hexagonal fuel assemblies, namely a first type of fuel assembly with a heat pipe inserted in the center hole, a second type of fuel assembly with a fuel rod inserted in the center hole, and a third type of fuel assembly, wherein the third type of fuel assembly is obtained by rotating the second type of fuel assembly by 60°;

[0076] Step S132: The first type of fuel assembly, the second type of fuel assembly, and the third type of fuel assembly are arranged as follows: three second type fuel assemblies are spaced 120° apart in the six fuel assembly positions adjacent to the first type of fuel assembly, and the third type of fuel assembly is arranged in the remaining three positions.

[0077] Each fuel assembly has multiple holes arranged in an equilateral triangular grid on its substrate. Fuel rods or heat pipes are inserted into these holes. The fuel rods and heat pipes are arranged at the hole level according to the following rules: each hole is surrounded by 6 adjacent holes at 60° intervals; for holes where fuel rods are inserted, 3 of the 6 adjacent holes are filled with heat pipes at 120° intervals, and the remaining 3 holes are filled with fuel rods; for holes where heat pipes are inserted, all 6 adjacent holes are filled with fuel rods. Through the coordinated arrangement at the assembly level and the hole level, each fuel rod in the entire reactor core is surrounded by at least three heat pipes.

[0078] Optionally, when the above-mentioned components are arranged around the core, since there are no adjacent components, the outermost fuel rod port of the component is changed to load reflective material rods or combustible poison rods, thereby ensuring that the fuel rods around the core also have three heat pipes adjacent to them.

[0079] It should be noted that although a regular hexagonal fuel assembly is preferred in this embodiment because it can achieve a honeycomb-like close packing, filling the core cross-section without gaps, and facilitating a 60° rotationally symmetrical arrangement, those skilled in the art, based on the concept of this application, can also use other regular polygons capable of tessell planes as the basic shape of the fuel assembly, such as squares or equilateral triangles. When using these shapes, only the rotation angle of the assembly (e.g., 90° for a square, 60° or 120° for an equilateral triangle) and the arrangement rules need to be adjusted accordingly to still achieve the staggered arrangement of fuel rods and heat pipes and redundant cooling. Such equivalent transformations based on the concept of this application should be included within the protection scope of this invention.

[0080] The heat pipe microreactor core and its arrangement method provided in this application can be used for the design and construction of various heat pipe microreactors, especially suitable for scenarios with high requirements for safety and compactness, such as space reactors, land-based small modular reactors, and mobile power sources. Its high redundancy cooling characteristics, flexible power control, and scalable core structure have good industrial applicability and market prospects.

[0081] Flowcharts are used in this application to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, various steps can be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0082] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0083] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0084] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0085] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0086] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of scope in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A heat pipe micropile core, characterized in that, include: Multiple hexagonal fuel assemblies, comprising at least three types: a first type fuel assembly with a heat pipe inserted in the center hole, a second type fuel assembly with a fuel rod inserted in the center hole, and a third type fuel assembly. The third type fuel assembly is obtained by rotating the second type fuel assembly by 60°. The first, second, and third type fuel assemblies are arranged in a honeycomb pattern in the reactor core, and the arrangement rule is as follows: in the six fuel assembly positions adjacent to the first type fuel assembly, there are three second type fuel assemblies spaced 120° apart, and the remaining three positions are occupied by the third type fuel assembly. Each fuel assembly has multiple holes arranged in an equilateral triangular grid on its base. Fuel rods or heat pipes are inserted into these holes. The fuel rods and heat pipes are arranged at the hole level according to the following rules: each hole is surrounded by 6 adjacent holes at 60° intervals; for a hole where a fuel rod is inserted, 3 of the 6 adjacent holes are occupied by heat pipes at 120° intervals, and the remaining 3 holes are occupied by fuel rods; for a hole where a heat pipe is inserted, all 6 adjacent holes are occupied by fuel rods. Each fuel rod in the entire reactor core is surrounded by at least three heat pipes, and the ratio of the number of fuel rods to the number of heat pipes in the core is approximately 2:

1.

2. The heat pipe micropile core as described in claim 1, characterized in that, Also includes: The first combustible poison assembly is composed of the second type of fuel assembly, in which the fuel rods in the hexagonal corner regions are replaced with combustible poison rods; The second combustible poison assembly is formed by replacing the fuel rods in the hexagonal corner regions with combustible poison rods from the third type of fuel assembly.

3. The heat pipe micropile core as described in claim 2, characterized in that, In the arrangement of the first combustible poison assembly, there are 3 of the third type of fuel assemblies arranged at 120° intervals among the 6 fuel assemblies adjacent to it; in the arrangement of the second combustible poison assembly, there are 3 of the second type of fuel assemblies arranged at 120° intervals among the 6 fuel assemblies adjacent to it.

4. The heat pipe micropile core as described in claim 1, characterized in that, The reactor core includes an inner fuel zone and an outer fuel zone. The fuel rods in the inner fuel zone use low-enrichment fuel, while the fuel rods in the outer fuel zone use high-enrichment fuel.

5. The heat pipe micropile core as described in claim 1, characterized in that, It also includes a reactivity control system, which comprises multiple drums arranged around the core, each drum having an absorber on one side and a reflective material on the other side.

6. The heat pipe micropile core as described in claim 5, characterized in that, The plurality of drums includes a plurality of first-size drums arranged at six notch locations around the core.

7. The heat pipe micropile core as described in claim 6, characterized in that, The plurality of drums also includes a plurality of second-size drums, the second-size drums being smaller than the first-size drums, and the second-size drums being arranged in pairs and interspersed between adjacent first-size drums.

8. The heat pipe micropile core as described in claim 1, characterized in that, It also includes at least one stop bar assembly, which is arranged among multiple fuel assemblies.

9. A method for arranging the core of a heat pipe micropile, characterized in that, Includes the following steps: At least three types of regular hexagonal fuel assemblies are provided: a first type of fuel assembly with a heat pipe inserted in the central hole, a second type of fuel assembly with a fuel rod inserted in the central hole, and a third type of fuel assembly. The third type of fuel assembly is obtained by rotating the second type of fuel assembly by 60°. Each fuel assembly has multiple holes arranged in an equilateral triangular grid on its base. Fuel rods or heat pipes are inserted into the holes. The fuel rods and heat pipes are arranged at the hole level according to the following rules: each hole is surrounded by 6 adjacent holes at 60° intervals; for a hole with a fuel rod inserted, 3 of the 6 adjacent holes are filled with heat pipes at 120° intervals, and the remaining 3 holes are filled with fuel rods; for a hole with a heat pipe inserted, all 6 adjacent holes are filled with fuel rods. The first type of fuel assembly, the second type of fuel assembly, and the third type of fuel assembly are arranged as follows: three of the six fuel assembly positions adjacent to the first type of fuel assembly are the second type of fuel assemblies spaced 120° apart, and the third type of fuel assemblies are arranged in the remaining three positions, so that each fuel rod in the entire core is surrounded by at least three heat pipes adjacent to it, and the ratio of the number of fuel rods to the number of heat pipes in the core is approximately 2:1.

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