A method and system for symmetric boundary treatment of a neutron transport characteristic line method

Abstract

The application belongs to the technical field of nuclear reactor physics numerical calculation, and discloses a symmetric boundary processing method and system of a neutron transport characteristic line method. A geometry core model is constructed through an MOC program, boundary conditions of the geometry core model are set, the geometry core model is arranged with characteristic lines to obtain characteristic line arrangement information, symmetry of the geometry core model is set, a corresponding additional module is generated, an equivalent complete module of the additional module is generated according to the symmetry based on the additional module, boundary segment angular flux of the equivalent complete module is calculated, and the equivalent complete module is calculated according to the characteristic line arrangement information and based on the boundary segment angular flux of the equivalent complete module and a known source term distribution to obtain the equivalent complete module. The application realizes reduction of the difficulty of characteristic line arrangement of the additional module, and further improves the efficiency of neutron transport calculation.

Description

Technical Field

[0001] This application relates to the field of numerical calculation technology in nuclear reactor physics, and in particular to a symmetric boundary processing method and system for the neutron transport characteristic line method. Background Technology

[0002] Reactor physics analysis is fundamental to the analysis and computation of nuclear reactor systems. By solving the neutron transport equations, core reactivity and the fine power distribution across the entire reactor are obtained. With the rapid development of high-performance computing clusters, the Method of Characteristics (MOC), a method that combines high computational accuracy, good geometric adaptability, precise handling of anisotropic scattering, and parallelization across multiple dimensions, has gradually become a crucial method for neutron transport calculation. However, due to the enormous computational scale and excessive computation time required for fine-grained full-core numerical simulations, reasonable symmetric approximations are needed to reduce the problem size and save computation time.

[0003] Currently, mainstream MOC programs employ modular ray casting. This method uses the same ray casting for identical modules, significantly increasing the efficiency of geometric preprocessing and reducing data storage. However, when dealing with symmetric boundary conditions of a complete geometric core, the core becomes 1 / 2, 1 / 3, or 1 / 6 of its original size, introducing additional module units. To perform calculations on the symmetrically processed core, these additional modules need to be processed to ensure accurate connection with other modules. Existing techniques for processing these additional modules involve directly re-ray casting them. The drawbacks of this method are its cumbersome ray casting process, lack of versatility, and significant inconvenience in programming, making code maintenance extremely difficult. Summary of the Invention

[0004] Therefore, embodiments of this application provide a symmetric boundary processing method and system for the neutron transport feature line method, which reduces the difficulty of feature line arrangement of additional modules and thus improves the computational efficiency of neutron transport.

[0005] Firstly, this application provides a symmetric boundary processing method for the neutron transport characteristic line method.

[0006] This application is achieved through the following technical solution:

[0007] A symmetric boundary handling method for neutron transport characteristic lines, the method comprising:

[0008] A geometric core model is constructed using the MOC program, the boundary conditions of the geometric core model are set, and feature lines are arranged on the geometric core model to obtain feature line arrangement information.

[0009] Set the symmetry of the geometric core model, generate the corresponding additional module, generate the equivalent complete module of the additional module according to the symmetry property, and calculate the boundary segment angular flux of the equivalent complete module.

[0010] Based on the feature line arrangement information, and using the boundary segment angular flux and known source term distribution of the equivalent complete module, transport calculations are performed on the equivalent complete module to obtain the standard flux and effective proliferation factor Keff of the equivalent complete module.

[0011] In a preferred embodiment of this application, the step of calculating the boundary segment angular flux of the equivalent complete module may further include:

[0012] The angular flux of a portion of the outer boundary segments of the equivalent complete module is obtained by scanning transport calculation. Based on the symmetry property, the angular flux of the portion of the outer boundary segments is copied to the symmetrical unknown boundary segments to obtain the angular flux information of all boundary segments of the equivalent complete module.

[0013] In a preferred embodiment of this application, the geometric core model may be further configured as a hexagonal core or a square core.

[0014] In a preferred embodiment of this application, the additional modules corresponding to the hexagonal core may be further configured to include, but are not limited to, 1 / 2 additional modules, 1 / 3 additional modules, 1 / 6 additional modules, or 1 / 12 additional modules.

[0015] The additional modules corresponding to the square core at the four corners include, but are not limited to, 1 / 2 additional modules, 1 / 4 additional modules, or 1 / 8 additional modules.

[0016] In a preferred embodiment of this application, if the geometric core model is a hexagonal core, the feature lines are arranged as follows:

[0017] Given the number of azimuth angles N within the angle range of (0, 2π), the desired ray spacing is... Where N is a multiple of 12;

[0018] Divide all azimuth angles into N / 12 groups. The number of azimuth angles within the range of (0, π / 6) is N / 12, and the azimuth angles are evenly distributed. Calculate the expected azimuth angle for each group.

[0019] Where s represents the group number of the azimuth angle, s = 1, 2…N / 12;

[0020] Based on the desired ray spacing and desired azimuth The number of rays m, n, l corresponding to the three adjacent edges of the hexagonal core are obtained as follows:

[0021]

[0022]

[0023] n = m + l

[0024] Where ceil represents the floor function, m represents the number of rays corresponding to one edge of the hexagonal core, n represents the number of rays corresponding to the first adjacent edge of m, l represents the number of rays corresponding to the second adjacent edge of m, and a is the edge length of the hexagonal core.

[0025] Calculate the first angle of each azimuth angle based on the number of rays. and ray spacing δ s :

[0026]

[0027]

[0028] According to the first angle The angles of the six azimuth angles in each group are obtained, where the ray spacing between the six azimuth angles is equal and is δ. s :

[0029]

[0030]

[0031] In a preferred embodiment of this application, if the geometric core model is a square core, the feature lines are arranged as follows:

[0032] Set initial ray angle Given the initial ray spacing d, and based on the base width a and side height b, calculate the number N of base feature lines. a and the number of side feature lines N b :

[0033]

[0034]

[0035] Based on the number N of the bottom feature lines a and the number N of the side feature lines b Regarding the initial ray angle The initial ray spacing d is corrected to obtain the corrected ray angle. And ray spacing d′:

[0036]

[0037]

[0038] In a preferred example of this application, the neutron transport equation for transport calculation of the equivalent complete module can be further configured as follows:

[0039]

[0040] in, denoted by neutron angular flux, g by energy group designation, i by fine grid number of the characteristic line method, t by characteristic line number, m by azimuth number, n by polar number, and s by characteristic line coordinates. Let q represent the total cross section of the g group for the fine mesh i using the characteristic line method. g,i Let g represent the distribution of the source terms of the fine mesh i in the characteristic line method.

[0041] Secondly, this application provides a symmetric boundary processing system for the neutron transport characteristic line method.

[0042] This application is achieved through the following technical solution:

[0043] A symmetric boundary processing system for the neutron transport characteristic line method, the system comprising:

[0044] The model building unit is used to build a geometric core model through the MOC program, set the boundary conditions of the geometric core model, arrange the feature lines of the geometric core model, and obtain the feature line arrangement information.

[0045] An equivalent module generation unit is used to set the symmetry of the geometric core model, generate corresponding additional modules, generate equivalent complete modules of the additional modules according to the symmetry properties, and calculate the boundary segment angular flux of the equivalent complete modules.

[0046] The transport calculation unit is used to perform transport calculations on the equivalent complete module based on the feature line arrangement information and the boundary segment angular flux and known source term distribution of the equivalent complete module, to obtain the standard flux and effective multiplication factor Keff of the equivalent complete module.

[0047] Thirdly, this application provides a computer device.

[0048] This application achieves its goal through the following technical solution:

[0049] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the symmetric boundary processing method of any of the above-described neutron transport characteristic line methods.

[0050] Fourthly, this application provides a computer-readable storage medium.

[0051] This application is achieved through the following technical solution:

[0052] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the symmetric boundary processing method of any of the above-described neutron transport characteristic line methods.

[0053] In summary, compared with the prior art, the beneficial effects of the technical solution provided in this application include at least the following: constructing a geometric core model through an MOC program, setting the boundary conditions of the geometric core model, arranging feature lines, and obtaining feature line arrangement information; setting the symmetry of the geometric core model, generating corresponding extra modules, generating equivalent complete modules of the extra modules based on the symmetry properties, and calculating the boundary segment angular flux of the equivalent complete modules; and using the feature line arrangement information of the complete modules to perform transport calculations on the equivalent complete modules. By utilizing the property that the extra modules are symmetric parts of the complete modules, the extra modules are equivalent to complete modules, and then the equivalent complete modules are solved. The modular arrangement of complete modules is used uniformly, avoiding the processing of extra modules, reducing the difficulty of implementing symmetric boundary conditions, reducing the scale of the computational problem, and thus improving the efficiency of whole-core neutron transport calculations. Attached Figure Description

[0054] Figure 1 A flowchart illustrating the symmetric boundary processing method of the neutron transport characteristic line method provided in an exemplary embodiment of this application;

[0055] Figure 2 A schematic diagram of the modular feature line arrangement provided for an exemplary embodiment of this application;

[0056] Figure 3 A schematic diagram of a complete module and additional modules of a hexagonal core provided for an exemplary embodiment of this application;

[0057] Figure 4 A schematic diagram of the boundary segmentation of a hexagonal core provided for an exemplary embodiment of this application;

[0058] Figure 5 A schematic diagram illustrating the symmetrical processing of an additional module for a hexagonal core provided in an exemplary embodiment of this application;

[0059] Figure 6 A schematic diagram of the modular feature line arrangement of a square core with four corners provided for an exemplary embodiment of this application;

[0060] Figure 7 A schematic diagram of modular feature line connections for a square core with four corners provided as an exemplary embodiment of this application;

[0061] Figure 8 A schematic diagram illustrating the symmetry of a rectangular core provided for an exemplary embodiment of this application;

[0062] Figure 9 A schematic diagram of an additional module for a rectangular core provided in an exemplary embodiment of this application;

[0063] Figure 10 A schematic diagram of module boundary segmentation for a rectangular stack core provided as an exemplary embodiment of this application;

[0064] Figure 11 A schematic diagram illustrating the symmetrical processing of an additional module for a rectangular core provided in an exemplary embodiment of this application. Detailed Implementation

[0065] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

[0066] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0067] Furthermore, the term "and / or" in this application is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this application, unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship.

[0068] In this application, the terms "first," "second," etc., are used to distinguish identical or similar items with essentially the same function. It should be understood that there is no logical or temporal dependency between "first," "second," and "nth," nor are there any restrictions on quantity or execution order.

[0069] The embodiments of this application will now be described in further detail with reference to the accompanying drawings.

[0070] In one embodiment of this application, a symmetric boundary processing method for the neutron transport characteristic line method is provided, the main steps of which are described below:

[0071] S10: Construct a geometric core model using the MOC program, set the boundary conditions for the geometric core model, and arrange the feature lines to obtain feature line arrangement information. Start the MOC program, allow the user to input the geometric core model, and set the boundary conditions. The geometric core model can be a hexagonal core model or a square core model. Further geometric preprocessing is performed on the geometric core model, and feature lines are arranged to obtain feature line arrangement information, such as azimuth angle and ray spacing, for subsequent transport calculations.

[0072] S20: Set the symmetry of the geometric core model to generate corresponding extra modules. Based on the extra modules, generate equivalent complete modules according to the symmetry properties, and calculate the boundary segment angular flux of the equivalent complete modules. Setting the symmetry of a hexagonal or square core model will generate corresponding extra modules. Taking the hexagonal core model as an example, setting 1 / 2 symmetry will generate 1 / 2 extra modules; setting 1 / 3 symmetry will generate 1 / 3 extra modules; setting 1 / 6 symmetry will generate 1 / 6 extra modules; setting 1 / 12 symmetry will generate 1 / 12 extra modules. Taking the square core model as an example, setting 1 / 2 symmetry will generate 1 / 2 extra modules; setting 1 / 4 symmetry will generate 1 / 4 extra modules; setting 1 / 8 symmetry will generate 1 / 8 extra modules. These extra modules are all located on the symmetry boundary of the complete module and are also symmetric parts of the complete module. The existing modular raycasting for additional modules is very cumbersome, lacks versatility, causes great inconvenience to programming, and makes code maintenance extremely difficult.

[0073] S30: Based on the characteristic line arrangement information, and based on the boundary segment angular flux of the equivalent complete module and the known source term distribution, the transport calculation is performed on the equivalent complete module to obtain the standard flux and effective multiplication factor Keff of the equivalent complete module.

[0074] Therefore, this application utilizes the symmetry property of the extra module to equate it to an equivalent complete module, and then uses the feature line arrangement information of the complete module to solve for the equivalent complete module, calculating the boundary segment angular flux of the equivalent complete module. This avoids modular feature line processing of the extra module and reduces the difficulty of implementing boundary conditions. During the feature line scanning solution iteration, boundary segment angular flux input is required. Since some boundary angular fluxes of the equivalent complete module cannot be calculated, the solution is to copy the calculated angular fluxes of some outer boundary segments to the uncalculated unknown boundary segment angular fluxes based on the symmetry property, thus obtaining all boundary segment angular fluxes. This reduces the computational problem size, thereby improving the computational efficiency of the entire reactor core neutron transport calculation.

[0075] Specifically, when using the characteristic line method to perform transport calculations on an equivalent complete module, the solution domain needs to be divided into fine meshes, each containing only one material. Assuming the spatial distribution of source terms within the fine mesh is known, dense characteristic lines in several directions are used to perform ray tracing on the finely meshed solution domain, determining the intersections of the characteristic lines and the fine mesh, and generating characteristic line information. Through repeated characteristic line scanning and internal / external iterations, the neutron flux distribution and the effective multiplication factor Keff are obtained. The neutron transport equation used in the transport calculation is:

[0076]

[0077] in, denoted by neutron angular flux, g by energy group designation, i by fine grid number of the characteristic line method, t by characteristic line number, m by azimuth number, n by polar number, and s by characteristic line coordinates. Let q represent the total cross section of the g group for the fine mesh i using the characteristic line method. g,i Let g represent the distribution of the source terms of the fine mesh i in the characteristic line method.

[0078] Furthermore, it is determined whether the calculated standard flux and effective proliferation factor Keff have converged. If they have converged, the calculation program ends; if they have not converged, the process returns to step S20 above to continue the next source iteration.

[0079] It should be noted that the basic principle of modular ray arrangement is as follows:

[0080] In reactor engineering, reactor cores are often composed of repetitive arrangements of components or cells with identical geometry and fuel layout. This results in numerous repetitive structures during feature line arrangement. To address these repetitive structures, only one geometric preprocessing step is needed, followed by feature line arrangement according to certain rules. This allows feature lines to connect end-to-end between modules and extend into the entire solution domain. Corresponding reflection boundary conditions can also be processed and connected. Thus, the program only needs to store feature line information for a few different types of modules. During transport calculations, only the feature line information of the corresponding module needs to be called, saving significant storage space and computational overhead. This is the modular feature line tracing method.

[0081] Example 1:

[0082] In the hexagonal core model, the feature lines are arranged as follows:

[0083] The user sets the number of azimuth angles within the (0, 2π) angle range to N, where N is a multiple of 12. The user also sets the desired ray spacing.

[0084] The number of azimuth angles within the (0, π / 6) angle range is N / 12. All azimuth angles are divided into N / 12 groups, and the user-preset azimuth angles are evenly distributed. The desired azimuth angle in each group is... The calculation formula is:

[0085] Where s represents the group number of the azimuth angle, s = 1, 2…N / 12;

[0086] Furthermore, based on the above calculations, the desired azimuth angle and the user-defined desired ray spacing To calculate the number of rays m, n, l passing through the three adjacent edges of the hexagonal core, such as... Figure 2 As shown, m represents the number of rays corresponding to one edge of the hexagonal core, n represents the number of rays corresponding to the first adjacent edge of m, l represents the number of rays corresponding to the second adjacent edge of m, and a is the edge length of the hexagonal core. The hexagonal core is a regular hexagon with each edge of equal length. The specific formulas for calculating m, n, and l are as follows:

[0087]

[0088]

[0089] n = m + l

[0090] Where ceil represents the floor function, used to correct the number of rays m, n, l passing through the three adjacent edges of the hexagonal core;

[0091] Next, based on the calculated number of rays, the first angle of each azimuth angle group is calculated. and ray spacing δ s First angle and ray spacing δ s The calculation formula is:

[0092]

[0093]

[0094] The ray spacing for each azimuth angle is equal, and is the ray spacing δ calculated above. s The specific formulas for calculating the six azimuth angles are as follows:

[0095]

[0096]

[0097] Handling of additional modules in the hexagonal core:

[0098] like Figure 3 The diagram shows a hexagonal core composed of three hexagonal modules. This hexagonal core may have, but is not limited to, 1 / 2, 1 / 3, 1 / 6, and 1 / 12 symmetries. Symmetrical processing of the core would disrupt the integrity of the modules, resulting in additional 1 / 2, 1 / 3, 1 / 6, and 1 / 12 modules, respectively. The disrupted modules cannot be arranged using the modular ray arrangement of the complete modules; a new ray arrangement is required, which is cumbersome and lacks versatility. To avoid processing these additional modules and simplify the procedure for greater versatility, this application proposes a scheme that utilizes symmetry properties to process the additional modules.

[0099] The following explanation will be based on module 1 / 12 as an example. Figure 4As shown, the symmetry of the hexagonal core is set to 1 / 12 symmetry. Based on this symmetry, the complete module is divided into 12 identical parts along the symmetry axes. s1, s2, s3, s4, s5, and s6 are the six symmetry axes dividing the complete hexagonal module, and a, b, c, d, e, f, g, h, i, j, k, and l are the module segment boundaries formed after cutting along the symmetry axes. These 12 additional modules all belong to the symmetric parts of the complete module. They can be used to restore the complete module to an equivalent complete module, and then the solution can be applied to the equivalent complete module. For the triangular portion in the upper left corner of module 1 / 12, the angular flux of its boundary segment f can be obtained through transport scanning. However, apart from the angular flux of boundary segment f, the angular fluxes of the other boundary segments a, b, c, d, e, g, h, i, j, k, l are unknown. To restore it to an equivalent complete module, the symmetry relationship between s1 and s2 of the equivalent complete module needs to be satisfied. The angular flux of the remaining unknown boundary segments is obtained by copying the angular flux of boundary segment f using the symmetry relationship, where the angular flux copy relationship is: g = h = i = j = k = l = a = b = c = d = f. Specifically, boundary segment g is symmetric to boundary segment f about the symmetry axis s2, so the angular flux of boundary segment f can be copied to boundary segment g, i.e., g = f; similarly, boundary segment e is symmetric to boundary segment f about the symmetry axis s1, e = f; boundary segment Boundary segment d is symmetric to boundary segment g about the axis of symmetry s1, d = g = f; boundary segment i is symmetric to boundary segment d about the axis of symmetry s2, i = d = g = f; boundary segment b is symmetric to boundary segment i about the axis of symmetry s1, b = i; boundary segment k is symmetric to boundary segment b about the axis of symmetry s2, b = k; boundary segment l is symmetric to boundary segment k about the axis of symmetry s1, l = k; boundary segment a is symmetric to boundary segment l about the axis of symmetry s2, a = l; boundary segment j is symmetric to boundary segment a about the axis of symmetry s1, j = a; boundary segment c is symmetric to boundary segment j about the axis of symmetry s2, c = j; boundary segment h is symmetric to boundary segment c about the axis of symmetry s1, h = c. Finally, the angular flux of all boundary segments of the equivalent complete module is obtained, and the characteristic line arrangement method of the complete module can be used to arrange the characteristic lines, and then the transport calculation can be performed.

[0100] For the rhomboid portion in the upper left corner of the 1 / 6 module, the angular flux of its boundary segments f and g can be calculated through transport scanning. However, the angular flux of the remaining boundary segments is unknown except for the angular flux of boundary segments f and g. To restore it to an equivalent complete module, the symmetry relationship between s1 and s3 of the equivalent complete module needs to be used to copy the angular flux of the remaining unknown boundary segments a, b, c, d, e, h, i, j, k, l from the angular flux of boundary segments f and g using the symmetry relationship. This yields the angular flux of all boundary segments of the equivalent complete module. The specific angular flux copying relationship is: e = f, d = g, c = g, b = f, a = f, l = g, k = g, j = f. Thus, the angular flux of all boundary segments is obtained.

[0101] Similarly, for the 1 / 3 module, the angular flux of its boundary segments f, g, h, i can be calculated by transport scanning. Except for the angular flux of the unknown boundary segments f, g, h, i, the equivalent complete module satisfies the symmetry relationship between s1 and s5 and is obtained by replication. The specific replication relationship of the angular flux is: e = f, d = g, c = h, b = i, a = f, l = g, k = h, j = i.

[0102] For module 1 / 2, the angular flux of its boundary segments f, g, h, i, j, k can be calculated by transport scanning. The angular flux of other unknown boundary segments can be obtained by copying the equivalent complete module, which satisfies the symmetry relationship about s1. The specific angular flux copying relationship is: l = k, a = j, b = i, c = h, d = g, e = f.

[0103] like Figure 5 As shown, by replacing all the extra modules of the 1 / 6 symmetric core with equivalent complete modules, a core consisting of three equivalent complete modules can be obtained. This core is composed of six identical modules, and transport scan calculation can be performed with only one modular feature line arrangement.

[0104] Example 2:

[0105] In a square core model, such as Figure 6 As shown, the feature lines are arranged as follows:

[0106] Initial ray angle The initial ray spacing d is set by the user in the input program. The modular bottom width a and side height b are known information. Based on the above information, the number N of bottom feature lines is calculated. a and the number of side feature lines N b The specific calculation formula is as follows:

[0107]

[0108]

[0109] Then, using the number N of the base feature lines calculated above... a and the number of side feature lines N b For the initial ray angle input The corrected ray angle is obtained by correcting the initial ray spacing d. The formula for the ray spacing d′ is as follows:

[0110]

[0111]

[0112] After arranging the feature lines according to the above method, the tail of any ray (feature line) is connected to the head of another ray, such as... Figure 7 As shown, the tail of ray number 9 connects to the head of ray number 6, the tail of ray number 6 connects to the head of ray number 3, the tail of ray number 3 connects to the head of ray number 10, the tail of ray number 10 connects to the head of ray number 7, the tail of ray number 7 connects to the head of ray number 4, the tail of ray number 4 connects to the head of ray number 1, the tail of ray number 1 connects to the head of ray number 8, the tail of ray number 8 connects to the head of ray number 5, the tail of ray number 5 connects to the head of ray number 2, and the tail of ray number 2 connects to the head of ray number 9, thus forming a cycle.

[0113] Handling of the extra modules in the square core at the four corners:

[0114] like Figures 8 to 9 As shown, Figure 8 a is a rectangular core composed of 5*5 square modules, which may have, but is not limited to, 1 / 2 symmetry. Figure 8 b), 1 / 4 symmetry ( Figure 8 c), 1 / 8 symmetry ( Figure 8 d). Symmetrical processing of the core will destroy module integrity, resulting in an additional 1 / 2 extra module ( Figure 9 b、 Figure 9 c. Figure 9 d), 1 / 4 additional module ( Figure 9 e), 1 / 8 additional module ( Figure 9 f). Specifically, the handling scheme for the 1 / 8 extra module will be explained using this as an example. For example... Figure 10 As shown, based on the symmetry property, the complete module is divided into 8 parts according to the axis of symmetry. s1, s2, and s3 are the three axes of symmetry that divide the four-cornered square core, and a, b, c, d, e, f, g, and h are the module segment boundaries formed after the axis of symmetry is cut.

[0115] This application utilizes the property that the extra module is the symmetric part of the complete module to restore the extra module to the equivalent complete module and then solve the equivalent complete module. For the triangular 1 / 8 module located below the complete module, the angular flux of its boundary segment d can be calculated using transport scanning. The complete module is symmetric about the axes of symmetry s1, s2, and s3. The angular flux of the remaining unknown boundary segments a, b, c, e, f, g, and h is obtained by copying the symmetry relationships, where the copying relationships of the boundary angular flux are: a = b = c = e = f = g = h = d. Specifically, boundary segment c is symmetric to boundary segment d about s2, so c = d; boundary segment e is symmetric to boundary segment d about s3, so e = d; boundary segment f is symmetric to boundary segment e about s1, so f = e; boundary segment a is symmetric to boundary segment f about s2, so a = f; boundary segment h is symmetric to boundary segment a about s3, so h = a; and boundary segment g is symmetric to boundary segment b about s3, so g = b. Finally, the angular flux of all boundary segments of the equivalent complete module is obtained, and then the feature line arrangement method of the equivalent complete module can be used to arrange the feature lines and then perform transport calculations.

[0116] For the 1 / 4 module, the angular flux of its boundary segments d and e can be calculated by transport scanning. However, the angular flux of the other unknown boundary segments besides d and e must be obtained by copying the angular flux of boundary segments d and e using the symmetry of the complete module about s1 and s2. The specific copying relationship is: c = h = g = d, f = a = b = e.

[0117] For a 1 / 2 module, different 1 / 2 extra modules can be obtained according to different partitioning methods. The first type of 1 / 2 extra module is partitioned according to the axis of symmetry s2. The angular flux of its boundary segments d, e, f, g can be calculated by transport scan. The angular flux of the remaining unknown boundary segments is obtained by copying the angular flux of boundary segments d, e, f, g. The specific copying relationship is as follows:

[0118] c = d, b = e, a = f, h = g; The second type of 1 / 2 extra module is symmetrical about the axis of symmetry s1. The angular flux of its boundary segments b, c, d, e can be calculated through transport scan. The angular flux of the remaining unknown boundary segments is obtained by copying the angular flux of boundary segments b, c, d, e. The specific copying relationship is: a = b, h = c, g = d, f = e; The third type of 1 / 2 extra module is symmetrical about the axis of symmetry s3. The angular flux of its boundary segments b, c, d, e can be calculated through transport scan. The angular flux of the remaining unknown boundary segments is obtained by copying the angular flux of boundary segments a, b, c, d. The specific copying relationship is: h = a, g = b, f = c, e = d.

[0119] like Figure 11As shown, by replacing all the extra modules of the 1 / 8 symmetric core with equivalent complete modules, a core composed of equivalent complete modules can be obtained. This core consists of six identical modules, and transport scan calculations can be performed with only one modular feature line arrangement.

[0120] This application also provides a symmetric boundary processing system for the neutron transport characteristic line method, the system comprising:

[0121] The model building unit is used to build a geometric core model through the MOC program, set the boundary conditions of the geometric core model, arrange the feature lines of the geometric core model, and obtain the feature line arrangement information.

[0122] The equivalent module generation unit is used to set the symmetry of the geometric core model, generate the corresponding additional module, generate the equivalent complete module of the additional module according to the symmetry property, and calculate the boundary segment angular flux of the equivalent complete module.

[0123] The transport calculation unit is used to perform transport calculations on the equivalent complete module based on the feature line arrangement information and the boundary segment angular flux and known source term distribution of the equivalent complete module, to obtain the standard flux and effective multiplication factor Keff of the equivalent complete module.

[0124] In one embodiment, a computer device is provided, which may be a server.

[0125] The computer device includes a processor, memory, network interface, and database connected via a system bus. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media contains an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements the symmetric boundary processing method of any of the aforementioned neutron transport characteristic line methods.

[0126] In one embodiment, a computer-readable storage medium is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the computer program to implement the symmetric boundary processing method of any of the above-described neutron transport characteristic line methods.

[0127] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), Synchlink, DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0128] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the system described in this application can be divided into different functional units or modules to complete all or part of the functions described above.

Claims

1. A method of symmetric boundary treatment for a neutron transport characteristic line method, characterized by, The method includes: A geometric core model is constructed using an MOC program. Boundary conditions are set for the geometric core model, and feature lines are arranged to obtain feature line arrangement information. The geometric core model is either a hexagonal core or a square core. If the geometric core model is hexagonal, the feature line arrangement is as follows: Set (0, ) the number of azimuth angles in the angular range , the desired ray spacing where is a multiple of 12; Divide all azimuth angles into groups, the number of azimuth angles in the (0, ) angular range is , and the azimuth angles are evenly distributed, calculate the expected azimuth angle of each group of azimuth angles : wherein denotes the group number of the azimuth angle, ; based on the desired radial spacing and the desired azimuthal angle to obtain the number of rays corresponding to three adjacent edges of the hexagonal core : ， ， ， where ceil denotes the ceiling function, denotes the number of rays corresponding to one edge of the hexagonal core, denotes the number of rays corresponding to the first adjacent edge of the hexagon, denotes the number of rays corresponding to the second adjacent edge of the hexagon, is the length of the edge of the hexagonal core; calculating a first angle for each set of azimuth angles from the number of rays and ray spacing : ， ； According to the first angle , the angle of each azimuth angle in the group is obtained, wherein the ray spacing of the six azimuth angles is equal, and each is : ； If the geometric core model is a square core, the feature lines are arranged as follows: Set initial ray angle And initial ray spacing Based on base width And side height Calculate base feature line number And side feature line number : ， ； based on the number of bottom edge feature lines and the number of side edge feature lines , the initial ray angle and the initial ray spacing are corrected to obtain the corrected ray angle and ray spacing : ， ； Set the symmetry of the geometric core model, generate the corresponding additional module, generate the equivalent complete module of the additional module according to the symmetry property, and calculate the boundary segment angular flux of the equivalent complete module. Specifically, the step of calculating the angular flux of the boundary segments of the equivalent complete module includes: obtaining the angular flux of a portion of the outer boundary segments of the equivalent complete module through scanning transport calculation, and copying the angular flux of the portion of the outer boundary segments to the symmetrical unknown boundary segments based on the symmetry property to obtain the angular flux information of all boundary segments of the equivalent complete module. Based on the feature line arrangement information, and using the boundary segment angular flux and known source term distribution of the equivalent complete module, transport calculations are performed on the equivalent complete module to obtain the standard flux and effective proliferation factor Keff of the equivalent complete module.

2. The symmetric boundary treatment method of the neutron transport characteristic line method according to claim 1, characterized in that, The hexagonal core corresponds to an additional module comprising An additional module, An additional module, An additional module or An additional module; The four-cornered core corresponds to an additional module comprising An additional module, An additional module or An additional module.

3. The symmetric boundary treatment method of the neutron transport characteristic line method according to claim 1, characterized in that, The neutron transport equations for transport calculations on the equivalent complete module are as follows: ， where, denotes the neutron angular flux, denotes the energy group index, denotes the characteristic line method fine mesh index, denotes the characteristic line index, denotes the azimuthal angle index, denotes the polar angle index, denotes the characteristic line coordinate, denotes the g-group total cross section of the characteristic line method fine mesh i, denotes the g-group source term distribution of the characteristic line method fine mesh i.

4. A system for symmetric boundary treatment of a neutron transport characteristic line method, characterized in that, The system includes: The model building unit is used to construct a geometric core model through an MOC program, set the boundary conditions of the geometric core model, arrange feature lines on the geometric core model, and obtain feature line arrangement information; wherein, the geometric core model is a hexagonal core or a square core; if the geometric core model is a hexagonal core, the feature line arrangement method is as follows: Set (0, number of azimuth angles in the angular range desired ray spacing wherein is a multiple of 12; Divide all azimuth angles into groups, where (0, ) is the angle range of the azimuth number , and the azimuth angles are evenly distributed, calculate the expected azimuth angle of each group of azimuth angles : wherein denotes the group number of the azimuth angle, ; based on the desired radial spacing and the desired azimuthal angle to obtain the number of rays corresponding to three adjacent edges of the hexagonal core : ， ， ， where ceil denotes the ceiling function, denotes the number of rays corresponding to one edge of the hexagonal core, denotes the number of rays corresponding to the first adjacent edge of the hexagon, denotes the number of rays corresponding to the second adjacent edge of the hexagon, is the length of the edge of the hexagonal core; a first angle of each set of azimuth angles is calculated from the number of rays and the ray spacing : ， ； According to the first angle , the angle of each azimuth angle in the group is obtained, wherein the ray spacing of the six azimuth angles is equal, and is : ； If the geometric core model is a square core, the feature lines are arranged as follows: Set initial ray angle And initial ray spacing Based on base width And side height Calculate base feature line number And side feature line number : ， ； based on the number of bottom edge feature lines and the number of side edge feature lines , the initial ray angle and the initial ray spacing are corrected to obtain a corrected ray angle and a ray spacing : ， ； An equivalent module generation unit is used to set the symmetry of the geometric core model, generate corresponding additional modules, generate equivalent complete modules of the additional modules according to the symmetry properties, and calculate the boundary segment angular flux of the equivalent complete module. Specifically, the equivalent module generation unit is used to obtain the angular flux of a portion of the outer boundary segments of the equivalent complete module through scan transport calculation, and copy the angular flux of the portion of the outer boundary segments to the symmetrical unknown boundary segments based on the symmetry properties to obtain the angular flux information of all boundary segments of the equivalent complete module. The transport calculation unit is used to perform transport calculations on the equivalent complete module based on the feature line arrangement information and the boundary segment angular flux and known source term distribution of the equivalent complete module, to obtain the standard flux and effective multiplication factor Keff of the equivalent complete module.

5. A computer device, comprising: The method includes a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method according to any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the method according to any one of claims 1 to 3.

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