Petal-shaped spiral fuel pressurized water reactor core

Abstract

The invention discloses a petal-shaped spiral fuel pressurized water reactor core, and relates to the technical field of nuclear reactors. The problems that the design size of an existing pressurized water reactor is too large, and design parameters of a petal-shaped spiral fuel pressurized water reactor core are incomplete are solved. The reactor core comprises a plurality of fuel assemblies with hexagonal sections, and the hexagonal fuel assemblies are stacked layer by layer according to a honeycomb arrangement mode to form a cylindrical structure; the fuel assembly comprises a petal-shaped spiral fuel element, a burnable poison rod, a control rod, an inner shell and an outer shell. The outer shell and the inner shell are both of a regular hexagon structure. The inner shell is arranged in the outer shell, and the inner shell and the outer shell are concentric; the vertex of the outer shell and the vertex of the inner shell differ by 90 degrees; the burnable poison bars are respectively arranged at the inner vertex of the outer shell and the outer vertex of the inner shell; the control rod is arranged in the center of the inner shell; the petal-shaped spiral fuel elements are arranged between the inner shell and the outer shell in a hexagonal mode. The method is applied to the field of reactor design optimization.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear reactors, and in particular to the design of a petal-shaped spiral fuel pressurized water reactor core. Background Art

[0002] Under the condition of meeting the core safety, in order to further improve the economy of PWR, simplify the core structure and increase the heat exchange area of ​​fuel, researchers have proposed filament-shaped fuel elements, annular fuel elements, spherical fuel elements and petal-shaped fuel elements. Among them, petal-shaped helical fuel elements (PHF) can contain 2 to 8 petal-shaped petal-shaped fuel rods. This paper mainly explains four petal-shaped fuel rods (FPF) and three petal-shaped fuel rods (TPF). Compared with traditional fuel elements, PHF has the following advantages: (1) PHF has a larger surface area-to-volume ratio, which increases the contact area between the fuel rod and the coolant; (2) Due to its unique spiral structure, PHF can form self-support in the reactor while improving its mixing degree of the coolant. Studies have shown that at the same power level, the maximum critical heat flux density of the FPF assembly is 58% higher than that of the traditional round fuel rod; (3) The design of PHF reduces the concentration of stress points in the rod, which will help to extend the service life of the fuel rod. Traditional cylindrical fuel rods may crack or break during use due to stress concentration; (4) PHF can be adjusted according to different types of reactors to provide better adaptability and optimization.

[0003] Four-petal and three-petal fuel rods play an important role in improving reactor performance, extending fuel cycle, improving cooling effect and enhancing safety. However, there are still the following shortcomings: (1) The support principle of the combustible poison in the core of the petal-shaped spiral fuel PWR and the detailed design scheme of the petal-shaped spiral fuel PWR core are not clearly given; (2) At present, the research on petal-shaped fuel assemblies is mostly focused on thermal engineering, while the research on neutronic characteristics is relatively small. For the above reasons, it is very necessary to explore the design scheme of the PWR core based on petal-shaped fuel elements, make full use of the structural and thermal advantages of petal-shaped fuel rods, further reduce the size of existing PWRs, and optimize reactor design. Summary of the invention

[0004] Aiming at the problem that the current design size of pressurized water reactor is too large and the design parameters of petal-shaped spiral fuel pressurized water reactor core are incomplete, the present invention proposes a petal-shaped spiral fuel pressurized water reactor core, which is realized by the following technical solutions:

[0005] A petal-shaped spiral fuel pressurized water reactor core, the core comprising: a plurality of fuel assemblies with hexagonal cross-sections, the hexagonal fuel assemblies being stacked layer by layer in a honeycomb arrangement to form a cylindrical structure; the fuel assembly comprising a petal-shaped spiral fuel element, a burnable poison rod, a control rod, an inner shell and an outer shell; the outer shell and the inner shell are both regular hexagonal structures; the inner shell is arranged inside the outer shell, and the inner shell and the outer shell are concentric; the apex of the outer shell differs by 90 degrees from the apex of the inner shell; the burnable poison rod is respectively arranged at the inner apex of the outer shell and the outer apex of the inner shell; the control rod is arranged in the center of the inner shell; the petal-shaped spiral fuel element is arranged in a hexagonal shape between the inner shell and the outer shell.

[0006] Furthermore, a preferred embodiment is proposed, in which the fuel used by the petal-shaped spiral fuel element is a U-50% Zr alloy with a Zr mass fraction of 50%, and the cladding material of the petal-shaped spiral fuel element is a gadolinium-zirconium alloy.

[0007] Furthermore, a preferred embodiment is proposed, wherein the U-50% Zr alloy 235 The enrichment of U is less than 20%.

[0008] Furthermore, a preferred embodiment is proposed, wherein the petal-shaped spiral fuel element comprises petal-shaped fuel rods having 2 to 8 petals; and the hexagonal fuel assembly comprises 72 petal-shaped spiral fuel elements.

[0009] Furthermore, a preferred embodiment is proposed, wherein the petal-shaped spiral fuel element is a four-petal-shaped petal fuel rod or a three-petal-shaped petal fuel rod; wherein, the dimensions of the four-petal-shaped fuel rod are: the radius of the inner concave arc R is 0.1876 cm, the radius of the outer convex arc r is 0.0938 cm, and the length l of the connection between the outer convex arc and the inner concave arc is 0.1076 cm; the dimensions of the three-petal-shaped fuel rod are: the radius of the inner concave arc R is 0.2650 cm, the radius of the outer convex arc r is 0.1325 cm, and the length l of the connection between the outer convex arc and the inner concave arc is 0.1207 cm.

[0010] Furthermore, a preferred embodiment is proposed, wherein the burnable poison rod comprises two geometric sizes; the radius of the burnable poison rod located at the inner vertex of the outer shell is 0.483 cm; the radius of the burnable poison rod located at the outer vertex of the inner shell is 0.2515 cm.

[0011] Furthermore, a preferred embodiment is proposed, in which the combustible poisons used in the two combustible poison rods are both gadolinium-zirconium alloys, and the cladding material is 42CrNiMo.

[0012] Furthermore, a preferred embodiment is proposed, in which the radius of the control rod is 0.89 cm; the thickness of the cladding is 0.25 cm; the material of the control rod is B4C, and the material of the cladding is 42CrNiMo.

[0013] Furthermore, a preferred embodiment is proposed, wherein the inner shell and the outer shell are both made of E-110 alloy, the inner shell has a thickness of 0.07 cm and a side length of 1.776 cm; the outer shell has a thickness of 0.165 cm and a side length of 5.89 cm.

[0014] Furthermore, a preferred embodiment is proposed, in which the heights of the petal-shaped spiral fuel rods, burnable poison rods, control rods, and active areas of the inner shell and outer shell are all 120 cm.

[0015] The present invention is beneficial in that:

[0016] At present, the traditional pressurized water reactor design usually has a large volume, which not only affects the layout density of the core, but also increases the floor space and construction cost of the core. In the present invention, by introducing petal-shaped spiral fuel elements and hexagonal honeycomb arrangement, the present invention effectively optimizes the core structure, makes the layout of the fuel assembly more compact, improves the space utilization rate, and thus reduces the volume and size of the overall core. The unique design of using petal-shaped spiral fuel elements improves the density of the core, allowing the fuel elements to be more efficiently laid out in a limited space. The use of honeycomb arrangement and hexagonal structure allows the various components in the core to be arranged more compactly, which can maximize the use of space and reduce unused gaps, thereby improving the overall density and reaction efficiency of the core. Furthermore, there is no additional support structure inside the component, which reduces the flow resistance and ensures that the coolant can circulate effectively and smoothly inside the system, thereby improving the overall operating efficiency and stability of the system.

[0017] The traditional petal-shaped spiral fuel pressurized water reactor core design often lacks perfect parameters and specific optimization schemes, resulting in a lack of systematicity and operability in the design. The present invention specifies the various parameter settings of the core in detail in the design, enhancing the scientificity and systematicity of the design. The core fuel assembly adopts petal-shaped spiral fuel elements and is arranged in a hexagonal layout to form a more stable core structure. The precise design between the inner and outer shells, including the relative layout of the outer shell and the inner shell, ensures the stability of the structure and the safety of the fuel. Burnable poison rods and control rods are provided to ensure the stability and safety of the core under high temperature and high pressure conditions.

[0018] The fuel utilization efficiency of traditional pressurized water reactor designs is often affected by the core design, resulting in low fuel utilization and even potential safety hazards in some cases. The present invention significantly improves the fuel utilization efficiency and enhances the safety of the core by optimizing the core structure. The combination of hexagonal fuel assemblies and petal-shaped spiral fuel elements can ensure the uniformity of the core during operation and more efficient use of fuel. The provision of combustible poison rods and control rods not only improves the reaction control capability of the core, but also enhances the ability to respond to possible over-temperature or over-pressure phenomena.

[0019] The core design of the present invention fully considers the heat exchange problem of the fuel assembly. The petal-shaped spiral fuel rod, with its unique spiral structure design, can not only increase the heat exchange area between the coolant and the fuel rod, but also enhance the stirring effect of the fuel rod on the coolant, thereby effectively improving the heat conduction efficiency of the core. The layout design of the inner and outer shells ensures that the coolant can flow through every area of ​​the core, reducing the heat accumulation phenomenon. The hexagonal fuel assembly and honeycomb arrangement make the core perform better in thermal engineering, effectively reducing local overheating and heat loss.

[0020] The unique spiral structure of the petal-shaped spiral fuel element in the present invention can form an independent self-supporting structure, thereby simplifying the core.

[0021] The invention is applied to the field of reactor design optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of the four-petal spiral fuel rod according to the eleventh embodiment, wherein R c represents the radius of the circumscribed circle of the fuel rod, h represents the connection length between the inner concave arc and the outer convex arc, r represents the radius of the outer convex arc, R represents the radius of the inner concave arc, and b represents the thickness of the cladding;

[0023] Figure 2 This is a schematic diagram of the structure of a three-petal spiral fuel rod according to the eleventh embodiment;

[0024] Figure 3 This is a schematic diagram of the structure of a small-diameter combustible poison rod according to Embodiment 11;

[0025] Figure 4 This is a schematic diagram of the structure of a large-diameter combustible poison rod according to Embodiment 11;

[0026] Figure 5 This is a schematic diagram of the control rod structure according to the eleventh embodiment;

[0027] Figure 6 This is a schematic diagram of the inner shell and the outer shell according to the eleventh embodiment;

[0028] Figure 7A radial cross-sectional schematic diagram of a petal-shaped spiral fuel pressurized water reactor assembly according to Embodiment 11;

[0029] Figure 8 It is a schematic axial cross-sectional view of the petal-shaped spiral fuel pressurized water reactor assembly without coolant according to the eleventh embodiment;

[0030] Fig. 9 This is a schematic diagram of the core structure of a four-petal-shaped spiral fuel pressurized water reactor according to the eleventh embodiment;

[0031] Fig.10 This is a schematic diagram of the core structure of a three-petal-shaped spiral fuel pressurized water reactor according to the eleventh embodiment;

[0032] Fig.11 This is a schematic diagram of the supporting principle of fuel rods in a petal-shaped spiral fuel pressurized water reactor assembly according to the eleventh embodiment;

[0033] Fig.12 A schematic diagram of the supporting principle of the burnable poison rod in the four-petal-shaped spiral fuel pressurized water reactor assembly according to the eleventh embodiment;

[0034] Fig.13 A schematic diagram of the supporting principle of the burnable poison rod in the three-petal-shaped spiral fuel pressurized water reactor assembly according to the eleventh embodiment;

[0035] Fig.14 A schematic diagram of the infinite proliferation coefficient of the petal-shaped spiral fuel pressurized water reactor assembly according to the eleventh embodiment changing with time;

[0036] Fig.15 This is a schematic diagram of energy spectrum comparison of a petal-shaped spiral fuel pressurized water reactor assembly according to the eleventh embodiment, wherein Flux represents flux and Energy represents energy;

[0037] In the figure, 1 represents a four-petal petal-shaped fuel rod (FPF), 2 represents a three-petal petal-shaped fuel rod (TPF), 3 represents a burnable poison rod located at the outer vertex of the inner shell, 4 represents a burnable poison rod located at the inner vertex of the outer shell, 5 represents a control rod, 6 represents an outer shell, 7 represents an inner shell, 8 represents a four-petal petal fuel assembly, and 9 represents a three-petal petal fuel assembly. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described 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, not all of the embodiments.

[0039] Embodiment 1. The present embodiment describes a petal-shaped spiral fuel pressurized water reactor core, the core comprising: a plurality of fuel assemblies with hexagonal cross-sections, the hexagonal fuel assemblies being stacked layer by layer in a honeycomb arrangement to form a cylindrical structure; the fuel assembly comprising petal-shaped spiral fuel elements, burnable poison rods, control rods, an inner shell and an outer shell; the outer shell and the inner shell are both regular hexagonal structures; the inner shell is arranged inside the outer shell, and the inner shell and the outer shell are concentric; the vertices of the outer shell and the inner shell differ by 90 degrees; the burnable poison rods are respectively arranged at the inner vertices of the outer shell and the outer vertices of the inner shell; the control rods are arranged in the center of the inner shell; the petal-shaped spiral fuel elements are arranged in a hexagonal shape between the inner shell and the outer shell.

[0040] The current traditional pressurized water reactor design usually has a large volume, which not only affects the layout density of the core, but also increases the core's floor space and construction cost. In this embodiment, by introducing petal-shaped spiral fuel elements and hexagonal honeycomb arrangement, this embodiment effectively optimizes the core structure, making the layout of the fuel assembly more compact and improving space utilization, thereby reducing the volume and size of the overall core. The unique design of using petal-shaped spiral fuel elements increases the density of the core, allowing the fuel elements to be more efficiently laid out in a limited space. The use of honeycomb arrangement and hexagonal structure not only improves the space utilization of the core, but also maintains good fluid dynamics performance.

[0041] The traditional petal-shaped spiral fuel pressurized water reactor core design often lacks complete parameters and specific optimization schemes, resulting in a lack of systematicity and operability in the design. This implementation method specifies the various parameter settings of the core in detail in the design, enhancing the scientificity and systematicity of the design. The core fuel assembly adopts petal-shaped spiral fuel elements and is arranged in a hexagonal layout to form a more stable core structure. The precise design between the inner and outer shells, including the relative layout of the outer shell and the inner shell, ensures the stability of the structure and the safety of the fuel. Burnable poison rods and control rods are provided to ensure the stability and safety of the core under high temperature and high pressure conditions.

[0042] The fuel utilization efficiency of traditional pressurized water reactor designs is often affected by the core design, resulting in low fuel utilization and even potential safety hazards in some cases. This implementation significantly improves the fuel utilization efficiency and enhances the safety of the core by optimizing the core structure. The combination of hexagonal fuel assemblies and petal-shaped spiral fuel elements can ensure the uniformity of the core during operation and more efficient use of fuel. The provision of burnable poison rods and control rods not only improves the reaction control capability of the core, but also enhances the ability to respond to possible over-temperature or over-pressure phenomena.

[0043] The core design of this embodiment fully considers the heat exchange problem of the fuel assembly. The petal-shaped spiral fuel rod, with its unique spiral structure design, can not only increase the heat exchange area between the coolant and the fuel rod, but also enhance the stirring effect of the fuel rod on the coolant, thereby effectively improving the heat conduction efficiency of the core. The layout design of the inner and outer shells ensures that the coolant can flow through every area of ​​the core, reducing the heat accumulation phenomenon. The hexagonal fuel assembly and honeycomb arrangement make the core perform better in thermal engineering, effectively reducing local overheating and heat loss.

[0044] Embodiment 2. This embodiment further limits the petal-shaped spiral fuel pressurized water reactor core described in Embodiment 1. The fuel used by the petal-shaped spiral fuel element is U-50%Zr alloy with a Zr mass fraction of 50%, and the cladding material of the petal-shaped spiral fuel element is gadolinium zirconium alloy.

[0045] The material used for the fuel used in the petal-shaped spiral fuel element in this embodiment is U-50% Zr, which has the following advantages compared with traditional UO2: ① U-50% Zr has a higher thermal conductivity and can transfer the heat generated by fission in time, thereby reducing the temperature of the fuel element; ② U-50% Zr exhibits better toughness and ductility at high temperatures. Under high-temperature operation, U-50% Zr is less likely to melt, which can improve the inherent safety of the core; ③ U-50% Zr has better chemical stability in high temperature and radiation environments, and can effectively reduce the risk of radiation damage and chemical reactions.

[0046] Embodiment 3: This embodiment further defines the petal-shaped spiral fuel pressurized water reactor core described in Embodiment 2. 235 The enrichment of U is less than 20%.

[0047] In this embodiment, the enrichment of 235U in the U-50% Zr alloy is less than 20%, which means that the uranium-235 enrichment of the fuel is low, much lower than the enrichment of traditional highly enriched uranium fuel. Low-enriched uranium can effectively reduce the intensity of the neutron source in the core, thereby reducing the risk of core overheating or excessive reactor power. This feature helps to improve the safety of the reactor, reduce the risk of power fluctuations during the operation of the nuclear reactor, and extend the service life of the reactor.

[0048] Embodiment 4. This embodiment further limits the petal-shaped spiral fuel pressurized water reactor core described in Embodiment 1. The petal-shaped spiral fuel elements include petal-shaped fuel rods with 2 to 8 petals; the hexagonal fuel assembly includes 72 petal-shaped spiral fuel elements.

[0049] Embodiment 5. This embodiment is a further limitation of the petal-shaped spiral fuel pressurized water reactor core described in Embodiment 4, wherein the petal-shaped spiral fuel element is a three-petal-shaped petal fuel rod 2; the inner concave arc radius R of the three-petal-shaped petal fuel rod 2 is 0.2650 cm, the outer convex arc radius r is 0.1325 cm, and the length l of the connection between the outer convex arc and the inner concave arc is 0.1207 cm.

[0050] When the petal-shaped spiral fuel element is a four-petal-shaped petal fuel rod 1, the radius of the inner concave arc R of the four-petal-shaped petal fuel rod 1 is 0.1876 cm, the radius of the outer convex arc r is 0.0938 cm, and the length l of the connection between the outer convex arc and the inner concave arc is 0.1076 cm.

[0051] Embodiment 6. This embodiment is a further limitation of the petal-shaped spiral fuel pressurized water reactor core described in Embodiment 1, wherein the burnable poison rod comprises two geometric sizes; the radius of the burnable poison rod 4 located at the vertex inside the outer shell is 0.483 cm; the radius of the burnable poison rod 3 located at the vertex outside the inner shell is 0.2515 cm.

[0052] Embodiment 7: This embodiment further limits the petal-shaped spiral fuel pressurized water reactor core described in Embodiment 6. The burnable poisons used in the two burnable poison rods are both gadolinium zirconium alloy, and the cladding material is 42CrNiMo.

[0053] Embodiment 8. This embodiment further limits the petal-shaped spiral fuel pressurized water reactor core described in Embodiment 1. The radius of the control rod 5 is 0.89 cm; the cladding thickness is 0.25 cm; the material of the control rod is B4C, and the cladding material is 42CrNiMo.

[0054] This embodiment is explained in conjunction with the seventh embodiment. The material used for the fuel rods, burnable poison rods and control rods is 42CrNiMo alloy. Its mechanical properties include: ① It has high tensile strength and good toughness to adapt to the problem of radiation swelling that may occur in the reactor; ② Because the alloy contains Cr and Mo, the 42CrNiMo alloy has excellent wear resistance to adapt to the self-supporting structure between the internal components of the assembly; ③ The 42CrNiMo alloy has good oxidation resistance and corrosion resistance. The neutron properties of 42CrNiMo include: ① The absorption cross section of 42CrNiMo for neutrons is relatively low, and it will not significantly absorb neutrons in a neutron radiation environment. Specifically, the reaction of 42CrNiMo alloy in the thermal neutron region is weak, and it is suitable for use in the thermal neutron environment of a pressurized water reactor; ② The shielding effect of 42CrNiMo alloy on neutrons is relatively weak, and neutrons can pass through the cladding to undergo fission reactions with the internal fuel.

[0055] Embodiment 9. This embodiment further limits the petal-shaped spiral fuel pressurized water reactor core described in embodiment 1. The inner shell 7 and the outer shell 6 are both made of E-110 alloy. The thickness of the inner shell 7 is 0.07 cm and the side length is 1.776 cm; the thickness of the outer shell 6 is 0.165 cm and the side length is 5.89 cm.

[0056] Embodiment 10. This embodiment further limits the petal-shaped spiral fuel pressurized water reactor core described in Embodiment 1, wherein the heights of the petal-shaped spiral fuel rods, burnable poison rods, control rods, and active areas of the inner shell and outer shell are all 120 cm.

[0057] Implementation Method 11: See Figures 1 to 15 This embodiment provides a specific example of a petal-shaped spiral fuel pressurized water reactor core described in the first embodiment, and is also used to explain the second to tenth embodiments, specifically:

[0058] The present invention provides a petal-shaped spiral fuel pressurized water reactor core structure, which solves the problems of over-sized design size of current pressurized water reactors and incomplete design parameters of petal-shaped spiral fuel pressurized water reactor cores. At the same time, the Monte Carlo method is used to perform neutronics calculation on the petal-shaped spiral fuel pressurized water reactor core structure of the present invention, and the core design is verified by the Monte Carlo neutronics method to ensure the rationality of the design and solve the shortcomings of petal-shaped spiral fuel rods in neutronics calculation. This method improves the accuracy of core design and effectively overcomes the limitations of traditional calculation methods in complex geometric structures.

[0059] The petal-shaped spiral fuel rod structure used in the present invention is as follows Figure 1 and Figure 2 The geometric characteristic parameters of PHF include the inner concave arc radius R, the outer convex arc radius r, the connection length l between the outer convex arc and the inner concave arc, and the radius of the outer circumscribed circle of the fuel rod is R. c , the cladding thickness is b, the height of the fuel rod is H, and the pitch of the fuel rod is P, so the definition of the helix angle is as follows:

[0060]

[0061] Where β is the helix angle, which indicates the area swept by the upper surface of the fuel rod compared to the lower surface. To ensure that the FPF and TPF have the same water-uranium ratio, the cross-sectional area of ​​both FPF and TPF is 0.342 cm during design. 2; At the same time, in order to ensure that the size of the assembly is not affected by the shape of the fuel rods, the FPF and TPF have the same circumscribed circle radius, which is 0.483 cm; the total number of PHFs is 72, and they are placed in a hexagonal box with a side length of 5.89 cm and a thickness of 0.165 cm in a hexagonal arrangement.

[0062] The combustible poison rod structure used in the present invention is as follows: Figure 3 and Figure 4 During the operation of the reactor, a large power peak factor is often not conducive to the operation of the reactor. Therefore, in order to ensure the safe and efficient operation of the reactor, a certain amount of burnable poison is often required to be placed in the component when designing the component to achieve the effect of flattening the power. The present invention designs two different burnable poisons for specific positions, one of which has an inner diameter r of 1. BP 0.2515cm, outer diameter R BP is 0.2810cm, and the inner diameter r of another combustible poison BP 0.483cm, outer diameter R BP is 0.513cm; among them, 6 burnable poison rods with a radius of 1cm are placed at the outer vertices of the hexagonal box with a thickness of 0.07cm and an outer side length of 1.776cm, and six burnable poison rods with a radius of 2cm are placed at the inner vertices of the hexagonal box with a thickness of 0.165cm and an outer side length of 5.89cm to flatten the core power.

[0063] The present invention adopts a control rod provided at the center of each component to control the reactivity through the control rod. The control rod structure adopted in the present invention is as follows Figure 5 As shown. In the reactor design process, it is necessary to consider the absorption and release of the reactor's reactivity during accident conditions and operation to ensure the stable operation of the reactor. Therefore, this component is designed Figure 3 The control rod shown has an inner diameter of 0.89 cm and an outer diameter of 1.14 cm. The control rod is located in the center of the assembly and changes the reactivity in the reactor by lifting and inserting the control rod.

[0064] The two hexagonal boxes used in the present invention are as follows: Figure 6 In actual situations, in order to efficiently replace components and fix the internal structures of components, it is often necessary to design structural elements for a single component. Therefore, the present invention designs two hexagonal boxes to fix components and divide the internal areas of components.

[0065] The radial section and axial section of the petal-shaped spiral fuel pressurized water reactor assembly implemented by the present invention are as follows: Figure 7 and 8The petal-shaped spiral fuel pressurized water reactor assembly can be obtained by combining and fixing the petal-shaped spiral fuel rod, two burnable poison rods, control rods and two hexagonal boxes.

[0066] The petal-shaped spiral fuel pressurized water reactor hexagonal grid element structure and core structure schematic diagram of the present invention is as follows Fig. 9 and Fig.10 As shown. Take 199 petal-shaped spiral fuel pressurized water reactor assemblies and arrange them in a hexagonal arrangement to obtain the petal-shaped spiral fuel pressurized water reactor core structure. The pressurized water reactor core of the present invention includes 199 assemblies, and the core is designed in accordance with the design standards of the pressurized water reactor. All design parameters meet the core design requirements of the pressurized water reactor, which is convenient for compatibility with existing pressurized water reactor technology and reduces implementation costs and technical risks.

[0067] The present invention provides a supporting principle between fuel rods and between fuel rods and burnable poison rods in an assembly, so there is no redundant supporting material inside the assembly to fix the fuel rods and the burnable poison rods. This design simplifies the assembly structure. Fig.11 This is a schematic diagram of the fuel rod support principle in the petal-shaped spiral fuel pressurized water reactor assembly implemented by the present invention. As shown in the figure, in order for the PHF to form an independent and stable self-supporting structure in the assembly, it is necessary to ensure that there are more than two contact points between the petal-shaped fuel rods. Therefore, for FPF, β≥90°; for TPF, β≥240°, and a certain dislocation angle needs to be formed between adjacent TPFs to form a self-supporting point.

[0068] Fig.12 and Fig.13 The present invention is a schematic diagram of the supporting principle of the burnable poison rods in the petal-shaped spiral fuel pressurized water reactor assembly. As shown in the figure, in the horizontal direction, for the combustible poison rod with an inner diameter of 0.2515 cm, it is subjected to two forces F1 and F2 from PHF in the horizontal direction respectively. At the same time, a force F3 is applied to it at the outer vertex of the hexagonal box with a thickness of 0.07 cm and an outer side length of 1.76 cm. The resultant force formed by these three forces is 0. Therefore, in the horizontal direction, for the combustible poison rod with an inner diameter of 0.2515 cm, a stable self-supporting structure can be formed; in the horizontal direction, for the combustible poison rod with an outer diameter of 0.483 cm, it is first subjected to two forces F4, F5, and F6 from PHF. At the same time, the inner side of the hexagonal box with a side length of 5.89 cm and a thickness of 0.165 cm will apply two inward forces F7 and F8 to the combustible poison rod. The resultant force of the above F4, F5, F6, and F7 acting on the combustible poison rod is zero, thereby forming a stable self-supporting structure.

[0069] The design parameters of the petal-shaped spiral fuel pressurized water reactor core structure implemented by the present invention are shown in Table 1:

[0070] Table 1 Design parameters of petal-shaped spiral fuel PWR core structure

[0071] parameter value Thermal power (MW(th)) 175 Electric power (MW(e)) 50 fuel U-50% Zr 235U enrichment ＜20％ Control rod material <![CDATA[B4C]]> Combustible poison stick material <![CDATA[22.92%Gd2O3+77.08%Zr]]> Shell material 42CrNiMo Component housing material E-110 Moderator / Coolant <![CDATA[H2O]]> Number of core components 199 Component layout Hexagonal layout Active area length (cm) 120 Outlet temperature(℃) 313 Inlet temperature(℃) 277 Design pressure(MPa) 15.7

[0072] The Monte Carlo calculation parameters of the petal-shaped spiral fuel pressurized water reactor assembly implemented by the present invention are shown in Table 2:

[0073] Table 2 Monte Carlo calculation parameters of petal-shaped spiral fuel PWR assembly

[0074]

[0075]

[0076] According to the parameters designed in Table 1 and Table 2, the present invention performs neutronic simulation on the assembly when the control rods are fully raised, wherein the schematic diagram of the infinite multiplication coefficient of the petal-shaped spiral fuel pressurized water reactor assembly changing with time and the schematic diagram of the energy spectrum comparison are as follows: Fig.14 and Fig.15 As shown:

[0077] Fig.14 This is a schematic diagram of the infinite proliferation coefficient of the petal-shaped spiral fuel pressurized water reactor assembly implemented by the present invention changing with time. It can be seen from the figure that by improving the design of the petal-shaped spiral fuel pressurized water reactor assembly, its effective operation time can be maintained at 17 to 19 months; Fig.15 This is a schematic diagram of the energy spectrum comparison of the petal-shaped spiral fuel pressurized water reactor assembly implemented in the present invention. As can be seen from the figure, the energy spectrum of the TPF assembly is softer, so its thermal neutron flux is higher.

[0078] The core design was verified by Monte Carlo neutronics to ensure the rationality of the design and solve the shortcomings of petal-shaped spiral fuel rods in neutronics calculation. This method improves the accuracy of core design and effectively overcomes the limitations of traditional calculation methods in complex geometric structures.

[0079] Although the preferred embodiments of the present disclosure have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present disclosure.

[0080] Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is also intended to include these modifications and variations.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure rather than to limit its protection scope. Although the present disclosure has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that after reading the present disclosure, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the protection scope of the disclosed claims to be approved.

Claims

1. A petal-shaped spiral fuel pressurized water reactor core, characterized in that: The core comprises: a plurality of fuel assemblies with hexagonal cross-sections, wherein the hexagonal fuel assemblies are stacked layer by layer in a honeycomb arrangement to form a cylindrical structure; the fuel assembly comprises a petal-shaped spiral fuel element, a burnable poison rod, a control rod, an inner shell and an outer shell; the outer shell and the inner shell are both regular hexagonal structures; the inner shell is arranged inside the outer shell, and the inner shell and the outer shell are concentric; the apex of the outer shell differs by 90 degrees from the apex of the inner shell; the burnable poison rod is respectively arranged at the inner apex of the outer shell and the outer apex of the inner shell; the control rod is arranged in the center of the inner shell; the petal-shaped spiral fuel element is arranged in a hexagonal shape between the inner shell and the outer shell.

2. The petal-shaped spiral fuel pressurized water reactor core according to claim 1, characterized in that: The fuel used by the petal-shaped spiral fuel element is a U-50% Zr alloy with a Zr mass fraction of 50%, and the cladding material of the petal-shaped spiral fuel element is a gadolinium-zirconium alloy.

3. The petal-shaped spiral fuel pressurized water reactor core according to claim 2, characterized in that: The U-50% Zr alloy 235 The enrichment of U is less than 20%.

4. The petal-shaped spiral fuel pressurized water reactor core according to claim 1, characterized in that: The petal-shaped spiral fuel element includes petal-shaped fuel rods with 2 to 8 petals; the hexagonal fuel assembly includes 72 petal-shaped spiral fuel elements.

5. The petal-shaped spiral fuel pressurized water reactor core according to claim 4, characterized in that: The petal-shaped spiral fuel element is a four-petal petal fuel rod or a three-petal petal fuel rod; wherein, the dimensions of the four-petal fuel rod are: the radius of the inner concave arc R is 0.1876cm, the radius of the outer convex arc r is 0.0938cm, and the length l of the connection between the outer convex arc and the inner concave arc is 0.1076cm; the dimensions of the three-petal fuel rod are: the radius of the inner concave arc R is 0.2650cm, the radius of the outer convex arc r is 0.1325cm, and the length l of the connection between the outer convex arc and the inner concave arc is 0.1207cm.

6. The petal-shaped spiral fuel pressurized water reactor core according to claim 1, characterized in that: The burnable poison rod includes two geometric sizes; the radius of the burnable poison rod located at the inner vertex of the outer shell is 0.483 cm; the radius of the burnable poison rod located at the outer vertex of the inner shell is 0.2515 cm.

7. The petal-shaped spiral fuel pressurized water reactor core according to claim 6, characterized in that: The burnable poison used in the two burnable poison rods is gadolinium-zirconium alloy, and the cladding material is 42CrNiMo.

8. The petal-shaped spiral fuel pressurized water reactor core according to claim 1, characterized in that: The radius of the control rod is 0.89 cm; the thickness of the cladding is 0.25 cm; the material of the control rod is B4C, and the material of the cladding is 42CrNiMo.

9. The petal-shaped spiral fuel pressurized water reactor core according to claim 1, characterized in that: The inner shell and the outer shell are both made of E-110 alloy. The inner shell has a thickness of 0.07 cm and a side length of 1.776 cm; the outer shell has a thickness of 0.165 cm and a side length of 5.89 cm.

10. The petal-shaped spiral fuel pressurized water reactor core according to claim 1, characterized in that: The heights of the petal-shaped spiral fuel rods, burnable poison rods, control rods, and active areas of the inner shell and outer shell are all 120 cm.

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