Core Structure and Liquid Metal Cooled Fast Reactor

Abstract

This application relates to the field of nuclear reactor technology, and particularly to a core structure and a liquid metal-cooled fast reactor. The core structure includes: a grid assembly, auxiliary assemblies, stainless steel assemblies, fuel assemblies, conditioning assemblies, and an irradiation assembly. Multiple channels are formed within the grid assembly; the auxiliary assemblies are located in the outermost channels; the stainless steel assemblies have channels closer to the center than the auxiliary assemblies; the fuel assemblies have channels closer to the center than the stainless steel assemblies; the conditioning assemblies have channels around the fuel assemblies; the irradiation assembly has channels near the center, as well as channels adjacent to the fuel assemblies and channels between the fuel assemblies and the stainless steel assemblies; the fuel in the fuel assemblies includes oxide fuel, and the total neutron flux of the fuel assemblies in the core structure is not less than a predetermined value. The core structure and liquid metal-cooled fast reactor provided by the embodiments of this application can provide a high neutron flux and belong to the category of high-flux reactors.

Description

Technical Field

[0001] The embodiments of this application relate to the field of nuclear reactor technology, and particularly to a core structure and a liquid metal cooled fast reactor. Background Technology

[0002] The statements herein are provided merely as background information in connection with this application and do not necessarily constitute prior art.

[0003] For neutron flux rates close to or greater than 5 × 10 15 n / (cm 2 A reactor with a flux density of 1000 kJ / m³ can be called a high-flux reactor. High-flux reactors play an important role in advanced fuel research, production of special isotopes, and exploration of basic nuclear technologies. However, my country currently lacks operational performance data on high-flux reactors, resulting in slow progress in related research. Summary of the Invention

[0004] A brief overview of this application is provided below to offer a basic understanding of certain aspects thereof. It should be understood that this overview is not an exhaustive summary of the application. It is not intended to identify key or essential parts of the application, nor is it intended to limit its scope. Its purpose is merely to present certain concepts in a simplified form as a prelude to the more detailed description that follows.

[0005] A first aspect of this application provides a reactor core structure comprising: a grid assembly, an auxiliary assembly, a stainless steel assembly, a fuel assembly, a conditioning assembly, and an irradiation assembly. A plurality of adjacent channels are formed within the grid assembly. The auxiliary assembly is disposed in the outermost channel of the plurality of channels. The stainless steel assembly is disposed in a channel closer to the center of the plurality of channels than the auxiliary assembly. The fuel assembly is disposed in a channel closer to the center of the plurality of channels than the stainless steel assembly. The conditioning assembly is used to regulate the reactivity of the reactor and is disposed in channels surrounding the channels where the fuel assembly is disposed. The irradiation assembly is used to be irradiated to produce desired materials and is disposed in a channel near the center of the plurality of channels, a channel adjacent to the fuel assembly, and a channel between the fuel assembly and the stainless steel assembly. The fuel in the fuel assembly includes oxide fuel, and the total neutron flux of the fuel assembly configured in the core structure is not less than a predetermined value.

[0006] A second aspect of the embodiments of this application provides a liquid metal-cooled fast reactor, which includes the core structure provided in the first aspect of the embodiments of this application.

[0007] The core structure and liquid metal-cooled fast reactor provided in the embodiments of this application can provide a high neutron flux rate and belong to the category of high-flux reactors. Attached Figure Description

[0008] To further illustrate the above and other advantages and features of this application, the specific embodiments of this application will be described in more detail below with reference to the accompanying drawings. The drawings, together with the following detailed description, are included in and form a part of this specification. Elements having the same function and structure are indicated by the same reference numerals. It should be understood that these drawings only depict typical examples of this application and should not be considered as limiting the scope of this application.

[0009] Figure 1 This is a schematic diagram of a core structure according to an embodiment of this application;

[0010] Figure 2 This is a diagram showing the maximum neutron fluence rate distribution of the reactor based on an embodiment of this application;

[0011] Figure 3 This is a diagram showing the maximum neutron flux rate distribution of the reactor at the EOC, provided according to an embodiment of this application.

[0012] Figure 4 This is a maximum radiation damage dose distribution diagram of each component within a cycle according to an embodiment of this application.

[0013] It should be noted that the accompanying drawings are not necessarily drawn to scale, but are shown only in a schematic manner without affecting the reader's understanding.

[0014] Explanation of reference numerals in the attached drawings: 10, auxiliary component; 11, shielding component; 12, storage component; 20, stainless steel component; 30, fuel assembly; 31, first fuel assembly; 32, second fuel assembly; 41, compensation rod; 42, safety rod; 43, passive rod; 44, regulating rod; 50, irradiation assembly; 60, opening. Detailed Implementation

[0015] Exemplary embodiments of this application will be described below with reference to the accompanying drawings. For clarity and brevity, not all features of actual implementations are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the development of any such actual embodiment to achieve the developer's specific goals, such as complying with constraints related to the system and business, and these constraints may vary depending on the implementation. Furthermore, it should be understood that while development work can be very complex and time-consuming, such development work is merely a routine task for those skilled in the art who benefit from the content of this application.

[0016] It should also be noted that, in order to avoid obscuring this application with unnecessary details, only the equipment structure and / or processing steps closely related to the solution according to this application are shown in the accompanying drawings, while other details that are not closely related to this application are omitted.

[0017] The following disclosure provides several different implementations or examples for carrying out this application. To simplify the disclosure of this application, specific examples of components and methods are described below. Of course, these are merely examples and are not intended to limit this application. In the description of the embodiments of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0018] See Figure 1 A first aspect of this application provides a reactor core structure comprising: a grid assembly, an auxiliary assembly 10, a stainless steel assembly 20, a fuel assembly 30, a conditioning assembly, and an irradiation assembly 50. A plurality of adjacent channels are formed within the grid assembly. The auxiliary assembly 10 is disposed in the outermost channel of the plurality of channels. The stainless steel assembly 20 is disposed in a channel closer to the center of the plurality of channels than the auxiliary assembly 10. The fuel assembly 30 is disposed in a channel closer to the center of the plurality of channels than the stainless steel assembly 20. The conditioning assembly is used to regulate the reactivity of the reactor and is disposed in channels surrounding the channels where the fuel assembly 30 is disposed. The irradiation assembly 50 is used to be irradiated to produce desired substances and is disposed in channels near the center of the plurality of channels, channels adjacent to the fuel assembly 30, and channels between the fuel assembly 30 and the stainless steel assembly 20. The fuel in the fuel assembly 30 includes oxide fuel, and the total neutron flux of the fuel assembly 30 configured as a core structure is not less than a predetermined value.

[0019] The predetermined value here could be, for example, 5 × 10 15 n / (cm 2 The core structure provided in the embodiments of this application can provide a value greater than 5.5 × 10⁻⁶. 15 n / (cm 2 The neutron flux rate of ·s) belongs to a high-flux reactor. Furthermore, using the NAS program, the nominal value of the reactor balance cycle total reactor breeder ratio provided in the embodiments of this application is calculated to be 0.30.

[0020] See Figure 1 In the embodiments of this application, the irradiation component 50 may occupy a single channel or seven channels to form an irradiation circuit. The irradiation circuit may be cooled by a suitable method as needed, such as lead-bismuth cooling, sodium cooling, or air cooling.

[0021] In the embodiments of this application, the fuel assembly 30 may use uranium oxide ceramic fuel as fuel pellets. The fuel assembly 30 employs a hexagonal outer tube and internally houses triangularly arranged fuel pellets. The fuel pellets are radially positioned by spiral metal wire winding. The total length of the fuel assembly 30 is 2375 mm, and the effective density of the fuel pellets is 8.38 g / cm³. 3 The coefficient of linear expansion of the core is 1.1 × 10⁻⁶. -5 / ℃.

[0022] In the embodiments of this application, the structural materials used for various components include austenitic steel (domestic code CN-1515) and iron-horse steel (code CN-FMS).

[0023] In some embodiments, the fuel assembly 30 includes a first fuel assembly 31 and a second fuel assembly 32. The first fuel assembly 31 is configured to be closer to the center of the plurality of channels than the second fuel assembly 32, and the enrichment of the second fuel assembly 32 is greater than that of the first fuel assembly 31. The channels of the first fuel assembly 31 are configured outside the channels of the irradiation assembly 50. The channels of the irradiation assembly 50 are also configured between the channels of the first fuel assembly 31 and the second fuel assembly 32, and between the channels of the second fuel assembly 32 and the stainless steel assembly.

[0024] Local power peaks in the reactor limit the total output power of the entire reactor. Therefore, power leveling is necessary to improve the overall output power. Thus, the fuel assembly 30 can be divided into a first fuel assembly 31 and a second fuel assembly 32. The first fuel assembly 31, located closer to the center of the multiple channels, has a relatively lower enrichment level, thus achieving power leveling. In the embodiments of this application, the U-235 enrichment levels of the first fuel assembly 32 and the second fuel assembly 32 can be 49.3% and 59.8%, respectively.

[0025] In some embodiments, the adjustment assembly includes a compensation rod 41, a safety rod 42, a passive rod 43, and an adjustment rod 44. The compensation rod 41, the safety rod 42, and the passive rod 43 are disposed at the junction of the channel for the first fuel assembly 31 and the channel for the second fuel assembly 32, and the adjustment rod 44 is disposed at the outer edge of the channel for the second fuel assembly 32.

[0026] The absorbers of the compensation rod 41, safety rod 42, passive rod 43 and regulating rod 44 are all made of boron carbide core blocks. The absorber rod bundle moves inside the outer sleeve of the regulating component, and its radial positioning method adopts wire winding and upper and lower grid plate positioning.

[0027] In some embodiments, the channel of the auxiliary component 10 is formed into a C-shaped structure, and a stainless steel component 20 is provided in the channel at the opening 60 of the C-shaped structure.

[0028] In some embodiments, the compensation rod 41, the safety rod 42, and the passive rod 43 are uniformly arranged circumferentially along the channel through which the first fuel assembly 31 is disposed, wherein the channel through which the passive rod 43 is disposed is the outermost channel through which the second fuel assembly 32 is disposed.

[0029] In some embodiments, the safety rod 42 has two channels, which are respectively located between the channels of the first fuel assembly 31 and the second fuel assembly 32.

[0030] In some embodiments, the position of each adjusting rod 44 in the channel is configured to form a triangle with one of the safety rods 42 and one of the compensation rods 41.

[0031] In some embodiments, the adjusting rod 44 has two channels, which are respectively located between the channels of the second fuel assembly 32 and the stainless steel assembly 20.

[0032] In some embodiments, the auxiliary component 10 includes a shield 11 and a storage component 12, the storage component being used to store spent fuel, and the channels provided with the storage component 12 being disposed between the channels provided with the shield 11.

[0033] In the embodiments of this application, the fuel assembly 30 can be replaced in a "non-discharge" manner, that is, all fuel assemblies 30 are irradiated to the irradiation assembly 50 at fixed positions within the grid assembly. After the specified irradiation cycle is reached, the spent fuel is unloaded into the storage unit 12, and a new fuel assembly 30 is installed in the corresponding position. During the entire burn-out process, the positions of other components remain unchanged.

[0034] In some embodiments, the maximum neutron flux obtained varies depending on the location of the channel of the irradiation component 50.

[0035] See Figures 2 to 3 , Figure 2 This is a diagram showing the maximum neutron fluence rate distribution of the reactor based on embodiments of this application. Figure 3 This is a maximum neutron fluence rate distribution map of the reactor at the EOC provided according to an embodiment of this application. Figure 2 and Figure 3 The units for all numbers in the middle are 1E15cm. -2 s -1 .Depend on Figure 2 and Figure 3It can be seen that the maximum neutron flux rate occurs at the center of the reactor core, which is the location for setting up the irradiation assembly. Furthermore, the overall trend shows that the farther the assembly is from the core center, the lower the neutron flux rate. Therefore, a suitable location can be selected based on the required irradiation dose for the irradiation assembly.

[0036] Figure 4 This is a maximum radiation damage dose distribution diagram of each component within a cycle, provided according to an embodiment of this application. Figure 4 The unit for the numbers in the middle is DPA / L. Figure 4 As can be seen, the maximum DPA occurs near the center of the fuel inner region, and the DPA distribution in this area is relatively uniform. The DPA gradually decreases from the center outwards. All irradiated locations in the reactor core can provide an irradiation capacity greater than 1200 DPA / L per year.

[0037] In some embodiments, the critical rod position for the equilibrium cycle can be obtained by iterative calculation of keff under different control rod positions in BOC and EOC. Table 1 shows the critical rod positions for the equilibrium cycle under different control rod positions, where the rod position is the height of the bottom of the control rod absorber relative to the lower end face of the active fuel region in the core.

[0038] Table 1. Critical rod position in equilibrium cycle / cm

[0039]

[0040] Embodiments of this application also provide a liquid metal-cooled fast reactor, which includes the core structure provided in any embodiment of this application.

[0041] Regarding the embodiments of this application, it should also be noted that, without conflict, the embodiments of this application and the features in the embodiments can be combined with each other to obtain new embodiments.

[0042] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. The scope of protection of this application shall be determined by the scope of the claims.

Claims

1. A core structure of a liquid metal cooled fast reactor, characterized by, It comprises: a grid assembly, in which a plurality of channels adjacent to each other are formed; an auxiliary assembly, which is arranged in the outermost channels of the plurality of channels; a stainless steel assembly, which is closer to the central channels of the plurality of channels than the auxiliary assembly; a fuel assembly, which is arranged in the channels closer to the central channels of the plurality of channels than the stainless steel assembly; a regulating assembly, which is used to regulate the reactivity of the liquid metal cooled fast reactor, and is arranged in the channels surrounding the channels in which the fuel assembly is arranged; an irradiation assembly, which is used to be irradiated to produce the required substances, and is arranged in the channels near the central part of the plurality of channels, and the channels adjacent to the fuel assembly, and the channels between the channels in which the fuel assembly and the stainless steel assembly are arranged; The fuel in the fuel assembly includes oxide fuel, and the fuel assembly is arranged such that the total neutron fluence rate of the core structure is not less than a predetermined value, which is 5 x 10 15 n / (cm 2 •s). The fuel in the fuel assembly includes oxide fuel, and the fuel assembly is arranged such that the total neutron fluence rate of the core structure is not less than a predetermined value, which is 5 x 10 15 n / (cm 2 •s). the fuel assembly comprises a first fuel assembly and a second fuel assembly, the first fuel assembly is arranged closer to the central channels of the plurality of channels than the second fuel assembly, and the enrichment of the second fuel assembly is greater than that of the first fuel assembly, the channels in which the first fuel assembly is arranged are arranged outside the channels in which the irradiation assembly near the central part is arranged; the channels in which the irradiation assembly is arranged are also arranged between the channels in which the first fuel assembly and the second fuel assembly are arranged, and between the channels in which the second fuel assembly and the stainless steel assembly are arranged; the U-235 enrichment of the first fuel assembly and the second fuel assembly (32) is 49.3% and 59.8% respectively; wherein the regulating assembly comprises compensation rods, safety rods, passive rods and regulating rods, the compensation rods, the safety rods and the passive rods are arranged at the junction of the channels in which the first fuel assembly is arranged and the channels in which the second fuel assembly is arranged, and the regulating rods are arranged at the outer edge of the channels in which the second fuel assembly is arranged.

2. The core structure of claim 1, wherein The channels in which the auxiliary assembly is arranged form a C-shaped structure, and the channels at the opening of the C-shaped structure are provided with the stainless steel assembly.

3. The core structure of claim 1, wherein The compensation rods, the safety rods and the passive rods are uniformly arranged along the circumference of the channels in which the first fuel assembly is arranged, and the channels in which the passive rods are arranged are the outermost channels of the channels in which the second fuel assembly is arranged.

4. The core structure of claim 3, wherein The number of channels in which the safety rods are arranged is two, which are arranged between the channels in which the first fuel assembly and the second fuel assembly are arranged.

5. The core structure of claim 3, wherein The position of the channel in which each regulating rod is arranged is arranged to form a triangle with one of the safety rods and one of the compensation rods.

6. The core structure of claim 5, wherein The number of channels in which the regulating rods are arranged is two, which are arranged between the channels in which the second fuel assembly and the stainless steel assembly are arranged.

7. The core structure of claim 1, wherein The auxiliary assembly comprises a shielding member and a storage member for storing spent fuel, and the channels in which the storage member is arranged are arranged between the channels in which the shielding member is arranged.

8. The core structure according to any one of claims 1 to 7, characterized in that The channels of the irradiation assembly are arranged at different positions, and the maximum neutron flux rate obtained by the channels is different.

9. A liquid metal cooled fast reactor, characterized in that, it comprises a core structure according to any one of claims 1 to 8.

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