Compact Core Applied to Onshore Mobile Power Supply and Onshore Mobile Power Supply

Abstract

The present invention provides a compact core for a land-based mobile power source and a land-based mobile power source, which relate to the technical field of nuclear reactors and are designed to solve the problem that the structure of current small land-based gas-cooled nuclear reactors is not compact enough. The compact core for a land-based mobile power source includes a core active region, a reflector layer coated on the periphery of the core active region, and a pressure-bearing layer coated on the periphery of the reflector layer. The core active region includes a plurality of hexagonal fuel elements, and the plurality of fuel elements are closely arranged in a honeycomb shape. The center of the fuel element is a fuel rod with a circular cross-section, and the six corners are coolant inlet channels; the fuel rod includes uranium carbide fuel; the coolant is a helium-xenon mixed gas. The land-based mobile power source includes the above-mentioned compact core for a land-based mobile power source. The compact core for a land-based mobile power source and the land-based mobile power source provided by the present invention have a more compact structure under the premise of the same power.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear reactors, and more particularly, to a compact core applied to an onshore mobile power source and an onshore mobile power source. Background Art

[0002] At present, the technical routes of land-based small nuclear reactors mainly focus on heat pipe reactors and gas-cooled reactors. For heat pipe reactors, although theoretically higher output power can be achieved, their power output is sensitive to the size and number of heat pipes. At the same time, drilling hundreds of thousands of millimeter-level channels on the matrix is a great challenge for industrial manufacturing. Therefore, from the perspective of feasibility, gas-cooled nuclear reactors will be a better solution.

[0003] Generally, a gas-cooled nuclear reactor includes a core. Inside the core are fuel elements, and gas flows directly through the above fuel elements as a coolant. The middle of the fuel element is fuel, and axial reflectors are provided at both ends of the fuel element to reduce neutron leakage. A gas gap and a fission gas plenum are placed behind the axial reflector to absorb fission gas and balance fission gas pressure. Fluid guiding devices are provided at both ends of the fuel element to control the coolant flow rate.

[0004] However, the current structure of gas-cooled nuclear reactors is not compact enough. Summary of the Invention

[0005] The first object of the present invention is to provide a compact core applied to an onshore mobile power source to solve the technical problem that the current structure of land-based small gas-cooled nuclear reactors is not compact enough.

[0006] The compact core applied to an onshore mobile power source provided by the present invention includes a core active zone, a reflector coated on the periphery of the core active zone, and a pressure-bearing layer coated on the periphery of the reflector. The core active zone includes a plurality of hexagonal fuel elements, and the plurality of fuel elements are closely arranged in a honeycomb shape. The fuel element has a graphite matrix, and the center of the fuel element is a fuel rod with a circular cross-section. The six corners of the fuel element are coolant inlet channels; the fuel rod includes uranium carbide fuel; the coolant is a helium-xenon mixed gas.

[0007] Further, the coolant inlet channel is coated with a cladding.

[0008] Further, the material of the cladding is molybdenum alloy.

[0009] Further, the pressure-bearing layer includes a first pressure-bearing layer and a second pressure-bearing layer arranged around the first pressure-bearing layer. There is a gap between the second pressure-bearing layer and the first pressure-bearing layer, and the gap forms a coolant outlet channel.

[0010] Further, the material of the reflective layer is beryllium.

[0011] Further, the enrichment of uranium in the fuel rod is between 19% and 20%.

[0012] Further, the compact core applied to the land mobile power source is provided with a central axis hole.

[0013] Further, the material of the pressure-bearing layer is stainless steel.

[0014] Further, the hexagon is a regular hexagon.

[0015] The beneficial effects brought by the compact core of the present invention applied to the land mobile power source are as follows:

[0016] By providing a compact core applied to the land mobile power source mainly composed of a core active zone, a reflective layer, and a pressure-bearing layer, wherein the reflective layer is coated on the periphery of the core active zone, and the neutrons leaked from the core active zone are reflected back to the core active zone through scattering to improve the neutron utilization efficiency of the nuclear reactor, so that the core power near the reflective layer rises; the pressure-bearing layer is coated on the periphery of the reflective layer, which plays a role of support, protection, and containment for the compact core applied to the land mobile power source, and also serves as a radiation protection barrier. The core active zone includes a plurality of fuel elements. The fuel elements are hexagonal, and a plurality of fuel elements are closely arranged in a honeycomb shape. The fuel elements are based on graphite, with a fuel rod having a circular cross-section in the center and coolant inlet channels at the six corners; the fuel rod includes uranium carbide fuel; the coolant is a helium-xenon mixed gas.

[0017] By providing a matrix made of graphite material, using graphite as a moderator material, which has a small thermal neutron absorption cross-section and a large scattering cross-section, can be used to significantly promote neutron fission reactions, and at the same time has a low cost, moderate strength, and can be used at high temperatures. The fuel elements of the compact core applied to the land mobile power source arrange graphite in the form of a matrix, and by opening holes in the graphite matrix to accommodate the fuel rod and allowing the helium-xenon mixed gas to pass through as the coolant, the neutron utilization rate can be improved, which is of great significance for power flattening.

[0018] Since the center of the fuel element is a fuel rod with a circular cross-section and the hexagon is the coolant inlet channel, that is, multiple coolant inlet channels are arranged around each fuel rod. When helium-xenon gas flows upward through the core as the coolant in the coolant inlet channels, it can carry away the fission heat generated by the nuclear reaction. Moreover, the multiple coolant inlet channels can also ensure sufficient contact between the helium-xenon gas as the coolant and the fuel element, reducing the helium-xenon pressure loss while increasing the power output of the whole reactor, improving the compactness of the core structure, and thus making the land mobile power structure applying this core also become compact, miniaturized, and highly mobile. Under the same volume condition, the power density is higher. Furthermore, during the operation of the compact core applied to the land mobile power, graphite as the matrix can conduct passive heat dissipation.

[0019] By using a helium-xenon mixed gas as the coolant, on the one hand, under the extreme working conditions of high temperature and high pressure, this setting makes the coolant not easily react with the solid materials in the active area of the core, ensuring the normal operation of the compact core applied to the land mobile power. On the other hand, the compressibility of this mixed gas is good, which can effectively reduce the size of the core while achieving the same power, facilitating the miniaturization and compact design of the compact core applied to the land mobile power.

[0020] The second object of the present invention is to provide a land mobile power to solve the technical problem that the structure of the current land mobile power is not compact enough.

[0021] The land mobile power provided by the present invention includes the above-mentioned compact core applied to the land mobile power.

[0022] The beneficial effects brought by the land mobile power of the present invention are:

[0023] By setting the above-mentioned compact core applied to the land mobile power in the land mobile power, since the above-mentioned compact core can achieve the same power while the structure becomes more compact, the structure of the land mobile power including it also becomes more compact, making the land mobile power have many excellent characteristics such as high power, long service life, mobility, and miniaturization. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0025] Figure 1Schematic longitudinal sectional view of a compact core applied to an onshore mobile power supply provided by an embodiment of the present invention;

[0026] Figure 2 Schematic cross-sectional view of a compact core applied to an onshore mobile power supply provided by an embodiment of the present invention;

[0027] Figure 3 is Figure 2 Local structure enlarged view at position A in

[0028] Description of reference numerals:

[0029] 100 - Core active area; 200 - Reflector; 300 - Pressure-bearing layer; 400 - Central axis hole;

[0030] 110 - Graphite; 120 - Fuel element; 140 - Cladding;

[0031] 111 - Fuel rod; 112 - Coolant inlet channel;

[0032] 310 - First pressure-bearing layer; 320 - Second pressure-bearing layer; 330 - Coolant outlet channel. Detailed implementation manners

[0033] Currently, there are mainly three ways of coolant circulation: 1. Open grid design. For this form of coolant circulation, although it is beneficial to reduce the volume and mass of the core and can also minimize the coolant pressure drop, it is difficult to control the coolant flow rate, which will bring local power peaks; 2. Annular channel design. This form of coolant circulation is the most commonly used design. The coolant flow rate and heat transfer can be well controlled, but detailed research on the size of the annular channel is required to reduce the coolant pressure drop; 3. Cermet fuel design. For this form of coolant circulation, although it can well balance the problems existing in the above two circulation methods, large-scale verification has not been carried out yet.

[0034] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of specific embodiments of the present invention will be given with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] Figure 1 Schematic longitudinal sectional view of a compact core applied to an onshore mobile power supply provided by this embodiment, Figure 2 Schematic cross-sectional view of a compact core applied to an onshore mobile power supply provided by this embodiment, Figure 3 is Figure 2 Local structure enlarged view at position A in Figures 1 to 3As shown in the figure, this embodiment provides a compact core applied to an onshore mobile power source, including a core active region 100, a reflector layer 200 coated on the periphery of the core active region 100, and a pressure-bearing layer 300 coated on the periphery of the reflector layer 200. Specifically, the core active region 100 includes a plurality of hexagonal fuel elements 120, and the plurality of fuel elements 120 are closely arranged in a honeycomb shape. The fuel element 120 has a graphite 110 as a matrix, and the center of the fuel element 120 is a fuel rod 111 with a circular cross-section. The six corners of the fuel element 120 are coolant inlet channels 112; the fuel rod 111 includes uranium carbide fuel, and the coolant is a helium-xenon mixed gas.

[0036] By setting a matrix made of graphite material, using graphite as a moderator material, which has a small thermal neutron absorption cross-section and a large scattering cross-section, it can be used to significantly promote the neutron fission reaction. At the same time, it has low cost, moderate strength, and can be used at high temperatures. The fuel element 120 of this compact core applied to an onshore mobile power source arranges graphite in the form of a matrix, and by opening holes in the graphite matrix 110 to accommodate the fuel rod 111 and allowing the helium-xenon mixed gas to pass through as a coolant, it can improve the neutron utilization rate and is of great significance for power flattening.

[0037] Since the center of the fuel element 120 is a fuel rod 111 with a circular cross-section and the six corners are coolant inlet channels 112, that is, a plurality of coolant inlet channels 130 are arranged around each fuel rod 111. When the helium-xenon gas flows through the core from bottom to top as a coolant in the coolant inlet channels 130, it can take away the fission heat generated by the nuclear reaction. Moreover, the plurality of coolant inlet channels 130 can also ensure the full contact between the helium-xenon gas as a coolant and the fuel element 120, reducing the helium-xenon pressure loss while increasing the power output of the whole reactor, improving the compactness of the core structure, and thus making the onshore mobile power source structure applying this core also become compact, miniaturized, and highly mobile. Under the same volume condition, the power density is higher. Moreover, during the operation of this compact core applied to an onshore mobile power source, the graphite 110 as a matrix can conduct passive heat dissipation.

[0038] By using a helium-xenon mixed gas as a coolant, on the one hand, under extreme working conditions of high temperature and high pressure, this setting makes the coolant not easily react with the solid materials in the core active region 100, ensuring the normal operation of the compact core applied to an onshore mobile power source. On the other hand, this mixed gas has good compressibility, can effectively reduce the size of the core while achieving the same power, and is conducive to the miniaturization and compactification design of this compact core applied to an onshore mobile power source.

[0039] It should be noted that in this embodiment, Figure 2 the core active region 100 in it can be regarded as severalFigure 3 The shown fuel element 120 is in a closely arranged honeycomb-like array. Among them, the radius of the core active area 100 is 600 mm, and the core height is 1200 mm.

[0040] In this embodiment, the opposite side distance of the hexagonal fuel element 120 is 29.45 mm.

[0041] In this embodiment, the fuel rod 111 is a cylindrical rod-like structure, the radius of the fuel rod 111 is 7 mm, and the radius of the coolant inlet channel 112 is 4 mm.

[0042] In this embodiment, the enrichment of uranium in the fuel rod 111 is between 19% and 20%. With such a setting, the fuel rod 111 can have a higher uranium density, a lower working temperature, and a smaller amount of fission gas release during burnup, and has excellent performance.

[0043] Preferably, the enrichment of uranium in the fuel rod 111 is 19.75%.

[0044] Please continue to refer to Figure 3 , in this embodiment, the coolant inlet channel 112 is coated with a cladding 140.

[0045] By coating the coolant inlet channel with the cladding 140, the mutual isolation of the helium-xenon mixed gas and the graphite 110 is achieved, which can play a certain protective role for the graphite 110, thereby avoiding the corrosion of solid materials caused by high-temperature gases.

[0046] Preferably, the material of the cladding 140 is molybdenum alloy. With such a setting, the corrosion resistance of the cladding 140 can be greatly improved, thereby further weakening the corrosion effect of high-temperature gases on solid materials.

[0047] In this embodiment, the outer diameter of the cladding 140 is 5 mm.

[0048] Please continue to refer to Figure 1 and Figure 2 , in this embodiment, the pressure-bearing layer 300 includes a first pressure-bearing layer 310 and a second pressure-bearing layer 320 arranged around the first pressure-bearing layer 310. Specifically, there is a gap between the second pressure-bearing layer 320 and the first pressure-bearing layer 310, and the above gap forms a coolant outlet channel 330.

[0049] In the compact core applied to the onshore mobile power supply, the coolant inlet channel 130 formed in the graphite 110 serves as the inner channel, and the coolant outlet channel 330 formed between the first pressure-bearing layer 310 and the second pressure-bearing layer 320 serves as the outer channel. As Figure 1As shown by the arrows in the figure, during the operation of the compact core applied to the land mobile power supply, the coolant inlet channel 130 and the coolant outlet channel 330 form a flow cycle: in the core active area 100, the helium-xenon mixed gas, as the coolant, flows upward from the coolant inlet channel 130 through the core and takes away the fission heat generated by the nuclear reaction. A large number of coolant inlet channels 130 ensure sufficient contact between the coolant and the fuel rods 111, reducing the helium-xenon pressure loss while increasing the power output of the whole reactor. The outflowing helium-xenon mixed gas enters the turbine to expand and do work, and finally drives the generator to generate electric power. The cooled helium-xenon mixed gas then flows isobarically through the coolant outlet channel 330 and returns to the compressor. This loop constitutes a closed Brayton cycle system for helium-xenon, which will help improve the utilization rate of helium-xenon and the cycle thermal efficiency of the whole machine. In addition, when discharging the residual heat of shutdown, the helium-xenon supply is closed and the body is opened to allow air to naturally pass through the coolant inlet channel 130 and the coolant outlet channel 330 for residual heat discharge. This design endows the compact core applied to the land mobile power supply with inherent safety mainly featuring the function of discharging residual heat with air as the coolant.

[0050] Specifically, in this embodiment, the material of the pressure-bearing layer 300 is stainless steel, that is: the materials of the first pressure-bearing layer 310 and the second pressure-bearing layer 320 are both stainless steel.

[0051] The pressure-bearing layer 300 in this material form has relatively high structural strength and can well withstand the pressure generated during the operation of the compact core applied to the land mobile power supply in this embodiment, thereby achieving the purpose of protecting the entire core.

[0052] Preferably, the materials of the first pressure-bearing layer 310 and the second pressure-bearing layer 320 are both austenitic 304 stainless steel.

[0053] In this embodiment, the thicknesses of the first pressure-bearing layer 310 and the second pressure-bearing layer 320 are both 20 mm; the thickness of the coolant outlet channel 330 is 50 mm.

[0054] Specifically, in this embodiment, the material of the reflector 200 is beryllium.

[0055] In this embodiment, the thickness of the reflector 200 is 350 mm.

[0056] Please continue to refer to Figure 1 and Figure 2 , in this embodiment, the compact core applied to the land mobile power supply is provided with a central axis hole 400.

[0057] By opening a central shaft hole 400 at the center of the compact core applied to the land mobile power supply, the core can respond to the overall design of the "three-in-one" compressor-core-turbine of the land mobile power supply and has good coupling characteristics with other components in the land mobile power supply. The central shaft hole 400 is used for the design of the main shaft mechanism of the above overall solution.

[0058] Specifically, in this embodiment, the fuel element 120 is in a regular hexagon shape. This setting can ensure the tight arrangement of multiple fuel elements 120 in the core active area 100. In this embodiment, the distance between opposite sides of the central shaft hole 400 is 187.06 mm.

[0059] Moreover, it can also ensure the full contact between the helium-xenon mixed gas and the fuel rod 111, so that during the flow of the helium-xenon mixed gas in the coolant inlet channel 130, the fission heat generated everywhere by the nuclear reaction can be evenly carried out.

[0060] Through the above design, the output thermal power of the compact core applied to the land mobile power supply in this embodiment is not less than 20 MWt, the full core life is not less than 3300 EFPD (1 EFPD means the core runs at full power for 1 day), the core fuel enrichment is less than 20%, and the fuel outlet temperature is not less than 1200 K.

[0061] In the compact core applied to the land mobile power supply, the specific parameters of each part structure are shown in Table 1 below.

[0062] Table 1 Structure Composition Table

[0063]

[0064]

[0065] In addition, this embodiment also provides a land mobile power supply, which includes the above compact core applied to the land mobile power supply.

[0066] By setting the above compact core applied to the land mobile power supply in the land mobile power supply, since the above compact core can achieve the same power while making the structure more compact, the structure of the land mobile power supply including it also becomes more compact, making the land mobile power supply have many excellent characteristics such as high power, long life, mobility, and miniaturization.

[0067] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

[0068] Finally, it should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0069] In the above embodiments, descriptions of orientations such as "upper" and "lower" are all based on the figures shown.

[0070] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A compact core applied to a land mobile power source, Characterized in that, It includes a core active area (100), a reflector layer (200) coated on the periphery of the core active area (100), and a pressure-bearing layer (300) coated on the periphery of the reflector layer (200). The core active area (100) includes a plurality of hexagonal fuel elements (120). The plurality of fuel elements (120) are closely arranged in a honeycomb shape. The fuel element (120) has a graphite (110) matrix. The center of the fuel element (120) is a fuel rod (111) with a circular cross-section. The six corners of the fuel element (120) are coolant inlet channels (112). By opening holes in the graphite (110) matrix to accommodate the fuel rod (111) and allowing a helium-xenon mixed gas to pass through as the coolant; the fuel rod (111) includes uranium carbide fuel; the coolant is a helium-xenon mixed gas; the coolant inlet channel (112) is coated with a cladding (140); the compact core applied to the land mobile power source is provided with a central axis hole (400).

2. The compact core applied to the land mobile power source according to claim 1, Characterized in that, The material of the cladding (140) is molybdenum alloy.

3. The compact core applied to the land mobile power source according to claim 1, Characterized in that, The pressure-bearing layer (300) includes a first pressure-bearing layer (310) and a second pressure-bearing layer (320) arranged around the first pressure-bearing layer (310). There is a gap between the second pressure-bearing layer (320) and the first pressure-bearing layer (310), and the gap forms a coolant outlet channel (330).

4. The compact core applied to the land mobile power source according to claim 1, Characterized in that, The material of the reflector layer (200) is beryllium.

5. The compact core applied to the land mobile power source according to claim 1, Characterized in that, The enrichment of uranium element in the fuel rod (111) is between 19% and 20%.

6. The compact core applied to the land mobile power source according to claim 1, Characterized in that, The material of the pressure-bearing layer (300) is stainless steel.

7. The compact core applied to the land mobile power source according to claim 1, Characterized in that, The hexagon is a regular hexagon.

8. A land mobile power source, Characterized in that, It includes the compact core applied to the land mobile power source according to any one of claims 1-7.

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