A first collision source determination method and apparatus for shielding computation

Abstract

The embodiment of the present specification belongs to the field of numerical simulation, and particularly relates to a first collision source determination method and device for shielding calculation, which comprises the following steps: obtaining information of a source term of a particle and information of a preset first collision point of the particle, wherein the preset first collision point represents a position where the particle collides with a material for the first time in a transport process; determining one or more geometric body models for representing a region passed through by the particle when the particle reaches the preset first collision point; calculating a passing distance of the particle in each of the geometric body models, and determining a first collision source corresponding to the preset first collision point according to the passing distance and material information corresponding to each of the geometric body models. The embodiment of the present specification solves the problem of high calculation cost of the first collision source in the existing simulation calculation.

Description

Technical Field

[0001] The embodiments in this specification relate to the field of numerical simulation, and in particular to a method and apparatus for determining the initial collision source for shielding calculations. Background Technology

[0002] In numerical simulations, it is often necessary to incorporate a First Collision Source (FCS) to mitigate the ray effect produced by the Discrete Ordinates Method (SN) and obtain more accurate shielding calculation results. The calculation of the First Collision Source involves determining the optical distance from the source term to the first collision point, which is the most time-consuming part of the entire process.

[0003] Currently, mesh-based ray tracing methods are mainly used in engineering practice. This method has an acceptable computational cost when using structured meshes, but the computational cost is too high for unstructured meshes. Since the structural information of unstructured meshes is more diverse, more computational resources are needed to calculate FCS, which limits its application value in practical engineering. Without combining FCS, it is difficult to overcome the ray effect generated by the SN method, resulting in low accuracy of shielding calculation. Summary of the Invention

[0004] This specification provides a method and apparatus for determining the first collision source in shielding calculations, which solves or at least partially solves the problem of high computational cost of the first collision source in existing shielding calculations.

[0005] To address the aforementioned technical problems, a first aspect of the embodiments of this specification provides a method for determining the initial collision source for shielding calculations, the method comprising:

[0006] Acquire information about the source term of the emitted particle and information about the preset first collision point of the particle, wherein the preset first collision point represents the position where the particle collides with the matter for the first time during the transport process;

[0007] Based on the area that the particle passes through when it reaches the preset first collision point, determine one or more geometric models to characterize the area it passes through;

[0008] The distance the particle travels through each of the geometric models is calculated, and based on the travel distance and the material information corresponding to each geometric model, the first collision source corresponding to the preset first collision point is determined.

[0009] Furthermore, before obtaining information about the source term of the emitted particle and the preset first collision point of the particle, the process also includes:

[0010] Construct a total mesh region containing the preset first collision point and the source item;

[0011] Generate a set of geometric models corresponding to the total grid region;

[0012] Based on each computing core and the total grid area, the grid area responsible for each computing core is determined;

[0013] The source item information, the set of geometric models and corresponding material information, and the mesh regions responsible for each computing core are sent to the corresponding computing core.

[0014] Further, calculating the distance the particle travels in each of the geometric models includes:

[0015] Based on the information of the source term and the information of the preset first collision point, the entry and exit positions of the particle in each of the geometric models are determined;

[0016] Each computing core calculates the travel distance of the particle corresponding to different first collision points in parallel based on the entry position and the exit position.

[0017] Further, based on the travel distance and the material information corresponding to each of the geometric models, the first collision source corresponding to the preset first collision point is determined, including:

[0018] Based on the distance the particle travels in each of the geometric models, the total distance the particle travels corresponding to the same material information is determined;

[0019] Obtain the total cross-section of the geometric model with the same material information;

[0020] The optical distance of the particle is determined based on the total travel distance and total cross-section of the particle in different materials;

[0021] Based on the optical distance, the first collision source corresponding to the preset first collision point is determined.

[0022] Furthermore, the method for determining the initial collision source used in the shielding calculation also includes:

[0023] Obtain information about the reflection boundary;

[0024] Construct a virtual source term that is symmetric about the reflection boundary and about the source term;

[0025] Based on the virtual source item and the preset first collision point, determine the intersection point of the travel path of the emitted particles of the virtual source item and the reflection boundary;

[0026] The travel distance of the emitted particles of the virtual source item in each of the geometric models is determined based on the area traversed by the emitted particles after they are emitted and reach the preset first collision point via the intersection point.

[0027] Furthermore, the method for determining the initial collision source used in the shielding calculation also includes:

[0028] The encryption threshold is determined based on the preset mesh refinement factor and the particle travel distance between the source term and the preset first collision point;

[0029] Encrypt the grid of the grid region containing the source item based on the encryption threshold;

[0030] Based on the travel distance, the grid and material information of the grid region where the source item is located, the first collision source corresponding to the preset first collision point is determined.

[0031] Furthermore, the grid of the grid region where the source item is located is encrypted according to the encryption threshold, including:

[0032] Determine whether the size of the grid in the grid region where the source item is located is greater than the encryption threshold;

[0033] If the determination is yes, recursively encrypt the grid in the grid region where the source term is located.

[0034] Furthermore, the mesh of the mesh region where the source term is located is recursively refined, including:

[0035] Divide the grid region containing the source term into subgrids;

[0036] Calculate the distance between the center distance of the sub-mesh and the preset first collision point;

[0037] The encryption threshold is updated based on the preset mesh refinement factor and the distance between the center distance of the sub-mesh and the preset first collision point.

[0038] When the size of a sub-mesh is greater than the updated encryption threshold, the sub-mesh is divided into sub-mesh sections, and the sub-mesh division operation based on the encryption threshold is continuously performed until the number of divisions reaches the preset mesh partitioning threshold.

[0039] A second aspect of the embodiments of this specification provides an apparatus for determining the first collision source for shielding calculations, the apparatus comprising:

[0040] The acquisition module is used to acquire information about the source term of the emitted particle and information about the preset first collision point of the particle, wherein the preset first collision point represents the position where the particle collides with the matter for the first time during the transport process.

[0041] The first determining module is used to determine one or more geometric models to characterize the area that the particle passes through when it reaches the preset first collision point.

[0042] The second determining module is used to calculate the travel distance of the particle in each of the geometric models, and determine the first collision source corresponding to the preset first collision point based on the travel distance and the material information corresponding to each of the geometric models.

[0043] A third aspect of the embodiments of this specification provides a computer device including a memory, a processor, and a computer program stored in the memory, wherein the computer program, when executed by the processor, executes instructions for the first collision source determination method for shielding calculations as described in any of the foregoing embodiments.

[0044] A fourth aspect of the embodiments of this specification provides a computer storage medium having a computer program stored thereon, which, when run by a processor of a computer device, executes instructions for the first collision source determination method for shielding calculations as described in any of the foregoing embodiments.

[0045] A fifth aspect of the embodiments of this specification provides a computer program product comprising a computer program that, when run by a processor of a computer device, executes instructions for the first collision source determination method for shielding calculations as described in any of the foregoing embodiments.

[0046] The method and apparatus for determining the first collision source for shielding calculations provided in this specification obtain information about the source term of the emitted particle and information about the preset first collision point of the particle to determine the region that the particle passes through when it reaches the preset first collision point. Based on the region it passes through, one or more geometric models representing the region are determined, thereby realizing the direct calculation of the particle's travel distance based on the geometric model, bypassing the continuous mesh, which greatly reduces the computational complexity. Finally, the first collision source is determined based on the travel distance and the material information corresponding to the geometric model, which reduces the cost of shielding calculations.

[0047] To make the above and other objects, features and advantages of the embodiments of this specification more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 A flowchart of the method for determining the initial collision source for shielding calculations in an embodiment of this specification is shown;

[0050] Figure 2 This specification illustrates a flowchart of an embodiment of the method for sending information to each computing core;

[0051] Figure 3 A flowchart illustrating the calculation of particle travel distance in an embodiment of this specification is shown;

[0052] Figure 4 This specification illustrates a flowchart of an embodiment for determining the initial collision source;

[0053] Figure 5 A flowchart of a method based on symmetric source terms, as illustrated in this specification, is shown.

[0054] Figure 6 The flowchart shown illustrates a scenario where the particle travel distance between the source item and a preset first collision point in an embodiment of this specification is less than a first preset threshold.

[0055] Figure 7 This specification shows a first flowchart of an embodiment of encrypting a mesh;

[0056] Figure 8 A second flowchart illustrating the encryption of the mesh according to an embodiment of this specification is shown;

[0057] Figure 9 A planar schematic diagram of the geometric model of an embodiment of this specification is shown;

[0058] Figure 10 A schematic diagram of the symmetric source term in an embodiment of this specification is shown;

[0059] Figure 11 A schematic diagram of the encrypted grid in an embodiment of this specification is shown;

[0060] Figure 12(a) shows a schematic diagram of the material distribution in the x, y plane of the environment in which the source item of the embodiment of this specification is located;

[0061] Figure 12(b) shows a schematic diagram of the material distribution in the x, z plane of the environment in which the source item of the embodiment of this specification is located;

[0062] Figure 13 A first schematic diagram of angular flux at different positions according to embodiments of this specification is shown;

[0063] Figure 14 This diagram illustrates the first schematic diagram showing the calculation deviation of angular flux at different positions according to embodiments of this specification;

[0064] Figure 15A second schematic diagram of angular flux at different positions according to embodiments of this specification is shown;

[0065] Figure 16 This diagram illustrates a second schematic showing the calculation deviation of angular flux at different positions according to embodiments of this specification.

[0066] Figure 17 A first schematic diagram of the angular flux distribution according to an embodiment of this specification is shown;

[0067] Figure 18 A second schematic diagram of the angular flux distribution according to an embodiment of this specification is shown;

[0068] Figure 19 A structural diagram of the initial collision source determination device for shielding calculations according to an embodiment of this specification is shown;

[0069] Figure 20 A structural diagram of a computer device according to an embodiment of this specification is shown.

[0070] Explanation of symbols in the attached drawings:

[0071] 1910. Acquisition Module;

[0072] 1920, First Determined Module;

[0073] 1930, Second Determining Module;

[0074] 2002, Computer equipment;

[0075] 2004, Processor;

[0076] 2006, Memory;

[0077] 2008, Drive mechanism;

[0078] 2010, Input / Output Module;

[0079] 2012, Input devices;

[0080] 2014, Output devices;

[0081] 2016, Presentation Equipment;

[0082] 2018, Graphical User Interface;

[0083] 2020, Network Interface;

[0084] 2022, Communication Link;

[0085] 2024, Communication Bus. Detailed Implementation

[0086] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the embodiments of this specification.

[0087] It should be noted that the terms "first," "second," etc., used in this specification, claims, and the foregoing drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0088] This specification provides the operational steps of the methods described in the embodiments or flowcharts, but based on conventional or non-inventive labor, more or fewer operational steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only possible execution order. In actual system or device products, the methods shown in the embodiments or drawings can be executed sequentially or in parallel.

[0089] It should be noted that the acquisition, storage, use, and processing of data in the technical solutions of the embodiments of this specification all comply with the relevant provisions of national laws and regulations.

[0090] It should be noted that in the embodiments of this specification, certain software, components, models and other existing solutions in the industry may be mentioned. These should be regarded as exemplary and are only intended to illustrate the feasibility of implementing the technical solutions of the embodiments of this specification. However, it does not mean that the applicant has used or necessarily used such solutions.

[0091] In the field of shielding computation, the Discrete Ordinates Method (SN) is a widely used numerical method that solves transport equations by discretizing the angular dimensions. However, when dealing with isolated point source problems or large cavity structures, the SN method often produces a ray effect at specific discrete angles, leading to inaccurate calculation results. To mitigate this effect, it is usually combined with the First Collision Source (FCS) method. Compared to core computation, shielding analysis involves more complex geometric features such as supporting structures, instruments, and components, thus placing higher demands on geometric description capabilities. Unstructured mesh techniques can meet this need, providing a more accurate geometric representation.

[0092] In calculating the initial collision source, the optical distance from the source to the target mesh needs to be calculated using ray tracing, which is the most time-consuming part of the entire process. The core of the ray tracing algorithm lies in determining the distance a ray travels through each type of material as it travels from the source point to the target.

[0093] Currently, mesh-based ray tracing methods are mainly used in engineering practice. While this method offers acceptable computational cost when using structured meshes, its geometric description capabilities are limited. When using unstructured meshes for spatial discretization, traditional ray tracing algorithms are not only computationally expensive but also difficult to implement in parallel, thus limiting their application value in practical engineering.

[0094] Therefore, in one embodiment of this specification, a method for determining the first collision source for shielding calculation is provided to solve the problem of high computational cost of the first collision source in existing shielding calculations.

[0095] Specifically, such as Figure 1 As shown, the method for determining the initial collision source used in the shielding calculation includes:

[0096] Step 110: Obtain information about the source term of the emitted particle and information about the preset first collision point of the particle, wherein the preset first collision point represents the position where the particle collides with the matter for the first time during the transport process;

[0097] Step 120: Based on the area that the particle passes through when it reaches the preset first collision point, determine one or more geometric models to characterize the area it passes through;

[0098] Step 130: Calculate the travel distance of the particle in each of the geometric models, and determine the first collision source corresponding to the preset first collision point based on the travel distance and the material information corresponding to each of the geometric models.

[0099] This embodiment obtains information about the source term of the emitted particle and the information about the preset first collision point of the particle to determine the area that the particle passes through when it reaches the preset first collision point. Based on the area it passes through, it determines one or more geometric models that characterize the area, thereby realizing the direct calculation of the particle's travel distance based on the geometric model, bypassing the continuous grid, which greatly reduces the computational complexity. Finally, the first collision source is determined based on the travel distance and the material information corresponding to the geometric model, which reduces the cost of shielding calculation.

[0100] The goal of shielding calculations is to solve the neutron transport equations. Considering the vacuum boundary and the isotropic point source at the target point, the multi-group transport equations are as follows:

[0101]

[0102] Where r represents spatial coordinates, Ω represents discrete directions, and g and g′ represent energy groups. This represents the total cross-section at position r. Let represent the scattering cross section at position r, i.e., the scattering coefficient from energy group g′ to g at position r; Ψ is the angular flux; G is the number of energy groups; L is the maximum order of the spherical harmonic expansion; Y is the spherical harmonic function; n represents the order of the spherical harmonic function; k represents the orientation quantum number of the spherical harmonic function; φ is the flux moment; and q fis It is a fission source, δ represents the unit impulse function, and q ext It is a fixed source.

[0103] When the initial collision source is introduced, the shielding problem can be decomposed into solving for the non-collision angle flux and the collision angle flux, i.e. Where, ψ u ψ represents the non-collision angular flux. c This represents the collision angle flux.

[0104] The non-collision angular flux is determined by the initial fixed source term and the optical distance. Then, the first collision source is determined using the non-collision angular flux. Solving for the collision angular flux requires treating the first collision source as a new source term and solving it using the Sub-Synthetic (SN) method. Therefore, when calculating the first collision source, shielding calculations typically divide the space containing the initial fixed source term and the first collision point into a total grid region composed of multiple grids. Based on the particle's travel distance within each grid and the corresponding material properties of the grid, the optical distance is calculated, and then the first collision source is determined from the optical distance.

[0105] In the embodiments of this specification, considering that the particle does not collide with the matter before reaching the first collision point, its travel direction during the transport process can be regarded as unchanged. Therefore, in order to reduce the amount of calculation of optical distance, the area traversed by the particle during its travel is constructed as a geometric model. Thus, when calculating the optical path, only the travel distance of the particle in the geometric model and the material information corresponding to the geometric model need to be considered to determine the optical distance traveled by the particle in each geometric model, thereby determining the total optical distance when the particle reaches the first collision point, and thus obtaining the first collision source. Figure 9 This is a planar schematic of an unstructured mesh region containing a fixed source term and the first collision point (the arrow in the figure points the fixed source term to the first collision point). The area with the thick border in the lower left corner is a schematic planar representation of a geometric model composed of multiple meshes.

[0106] In some embodiments of this specification, such as Figure 2 As shown, before obtaining the source term information of the emitted particle and the information of the preset first collision point of the particle, the process further includes:

[0107] Step 210: Construct a total mesh region containing the preset first collision point and the source item;

[0108] Step 230: Generate the set of geometric models corresponding to the total grid region;

[0109] Step 230: Determine the grid area responsible for each computing core based on each computing core and the total grid area;

[0110] Step 240: Send the information of the source item, the set of geometric models and the corresponding material information, and the mesh area responsible for each computing core to the corresponding computing core.

[0111] This embodiment constructs a total grid region containing target points and source terms, and determines the computational cores responsible for different grid regions. The optical distance is calculated in parallel by the computational cores, which improves the computational efficiency of the first collision source.

[0112] In unstructured meshes, to save computational resources, information is not shared between different computational cores. When calculating the optical distance of a particle, after the previous computational core determines the exit position of the particle, the next computational core adjacent to the mesh area can then know the entry direction of the particle and continue to calculate the optical distance of the particle in the mesh area that the computational core is responsible for. Therefore, the total optical distance calculation requires continuous waiting time and also requires information interaction between different computational cores, resulting in low computational efficiency.

[0113] In the embodiments described in this specification, by dividing the total grid area into different sub-grid areas, and then distributing the source item information, the geometric model and material information corresponding to the total grid area, and the divided sub-grid areas to the corresponding computing cores, each computing core has a global view and can directly determine the passage of particles when they reach the first collision point in their assigned grid area. This enables parallel computation of optical distance without the need for information exchange with the previous computing core. Furthermore, by constructing a geometric model to replace individual small grids, the amount of computational information is greatly reduced, achieving low-cost parallel computation. The geometric model can be a CAD model, through which the particle's passage distance in the model is directly calculated, or it can be other types of models; this specification does not limit this.

[0114] Specifically, in one embodiment of this specification, as follows: Figure 3 As shown, calculating the distance a particle travels through each of the aforementioned geometric models includes:

[0115] Step 310: Based on the information of the source item and the information of the preset first collision point, determine the entry position and exit position of the particle in each of the geometric models;

[0116] Step 320: Each computing core calculates in parallel the travel distance of the particle corresponding to different first collision points based on the entry position and the exit position.

[0117] In this embodiment, each computing core can determine the passage of a particle when it reaches the first collision point in its own grid area based on the information of the source term and the information of the preset first collision point (i.e., the entry and exit positions of each geometric model that the particle passes through when it reaches the first collision point in its own grid area after starting from the source term), thus eliminating the need for information interaction with the previous computing core and improving the efficiency of optical distance calculation.

[0118] Since each computing core stores source term information, the geometric model of the total grid region and corresponding material information, and the information of the sub-grid region it is responsible for, each computing core can determine the first collision point of its own grid region (each grid point in the grid region is regarded as the first collision point). It can determine the particle's travel direction based on the source term and the first collision point, thereby determining the travel situation of the particle when it reaches the first collision point in its own grid region after passing through each geometric model. After that, each computing core starts parallel computing to obtain the optical distance traveled by the particle corresponding to different first collision points.

[0119] In another embodiment of this specification, such as Figure 4 As shown, based on the travel distance and the material information corresponding to each of the geometric models, the first collision source corresponding to the preset first collision point is determined, including:

[0120] Step 410: Determine the total travel distance of the particle corresponding to the same material information based on the travel distance of the particle in each of the geometric models;

[0121] Step 420: Obtain the total cross-section of the geometric model with the same material information;

[0122] Step 430: Determine the optical distance of the particle based on the total travel distance and total cross-section of the particle in different materials;

[0123] Step 440: Determine the first collision source corresponding to the preset first collision point based on the optical distance.

[0124] This embodiment determines the total travel distance of a particle corresponding to the same material information based on the travel distance of the particle in each geometric model, and determines the total optical distance of the particle corresponding to the same material based on the total travel distance and the total cross section of the geometric model corresponding to the same material information, thereby further improving the efficiency of optical distance calculation.

[0125] In shielding calculations, the total cross section refers to the sum of the cross sections of all possible processes of particle-matter interaction, which is a physical quantity that characterizes the probability of particle-matter interaction. After obtaining the distance the particle travels in the geometric model, the total cross section is used as the weight of the travel distance and combined with the travel distance to obtain the optical distance. Then, the non-collision flux is determined based on the optical distance, and the first collision source is obtained by scattering (collision) calculation from the non-collision flux.

[0126] In another embodiment of this specification, such as Figure 5 As shown, the method for determining the initial collision source for shielding calculations also includes:

[0127] Step 510: Obtain information about the reflection boundary;

[0128] Step 520: Construct a virtual source term that is symmetric about the reflection boundary and about the source term;

[0129] Step 530: Based on the virtual source item and the preset first collision point, determine the intersection point of the travel path of the emitted particles of the virtual source item and the reflection boundary;

[0130] Step 540: Determine the travel distance of the emitted particles of the virtual source item in each of the geometric models based on the area traversed by the emitted particles of the source item when they reach the preset first collision point via the intersection point after being emitted.

[0131] This embodiment considers the problem of determining the particle travel distance in the reflection boundary problem. When the total grid area contains only part of the spatial information due to the setting of the reflection boundary, the total travel distance of the particles emitted by the source grid representing all spatial information can be determined by equivalent substitution without expanding the grid, thereby reducing the computing resources required by each computing core.

[0132] Figure 10 This is a schematic diagram of the source term including the reflection boundary. The right end of the reflection boundary is the real source term. The real source term is mapped with the reflection boundary as the axis of symmetry to obtain the virtual source term at the left end of the reflection boundary. The intersection point of the line connecting the virtual source term and the first collision point at the reflection boundary is determined. According to the symmetry property, the line connecting the real source term and the intersection point, as well as the line connecting the intersection point and the first collision point, can be combined to equivalently replace the travel distance of the particles emitted from the virtual source term.

[0133] Considering the following relationship between non-collision angular flux and travel distance:

[0134]

[0135] Where, ψ u Let τ represent the non-collision angular flux and τ represent the optical distance. This represents the distance from the source term r to the first collision point r. p The distance traveled.

[0136] Therefore, when When Ψ approaches 0, u It tends towards infinity. In other words, the shorter the travel distance, the higher the non-collision angle flux. Therefore, the calculation accuracy of short-distance travel has a significant impact on the calculation results.

[0137] Therefore, in one embodiment of this specification, as Figure 6 As shown, the method for determining the initial collision source for shielding calculations also includes:

[0138] Step 610: Determine the encryption threshold based on the preset mesh refinement factor and the particle travel distance between the source term and the preset first collision point;

[0139] Step 620: Encrypt the grid of the grid region where the source item is located according to the encryption threshold;

[0140] Step 630: Determine the first collision source corresponding to the preset first collision point based on the travel distance, the grid and material information of the grid region where the source item is located.

[0141] This embodiment considers encrypting the grid in the grid region where the source term is located when the encryption threshold is met, subdividing the original grid into smaller grids, determining the travel distance through the encrypted grid, and determining the first collision source corresponding to the preset first collision point based on the travel distance, the encrypted grid, and the material information corresponding to the encrypted grid, thereby improving the calculation accuracy of short-distance particle travel.

[0142] In another embodiment of this specification, such as Figure 7 As shown, a method for grid encryption is provided, including:

[0143] Step 710: Determine whether the size of the grid in the grid region where the source item is located is greater than the encryption threshold. If the determination is yes, proceed to step 720.

[0144] In step 710 above, if the size of the grid in the grid region where the source item is located is not greater than the encryption threshold, it means that the size of the grid region where the source item is located can meet the calculation accuracy requirements, and grid encryption can be omitted.

[0145] Step 720: Recursively encrypt the grid in the grid region where the source term is located.

[0146] This embodiment compares the size of the grid in the grid region where the source item is located with the encryption threshold, and recursively encrypts the grid in the grid region where the source item is located when the encryption threshold is met, thereby realizing the correlation between grid size and traversal distance and improving the effect of grid encryption.

[0147] The following formula is used to determine whether the grid is encrypted:

[0148]

[0149] in, This represents the distance from the source term r to the first collision point r. p The travel distance, where ε represents the mesh refinement factor. v cell This represents the mesh volume.

[0150] In another embodiment of this specification, such as Figure 8 As shown, recursively refining the mesh in the mesh region where the source term is located includes:

[0151] Step 810: Divide the grid of the grid region where the source term is located into sub-grids;

[0152] Step 820: Calculate the distance between the center distance of the sub-mesh and the preset first collision point;

[0153] Step 830: Update the encryption threshold according to the preset mesh refinement factor and the distance between the center distance of the sub-mesh and the preset first collision point;

[0154] Step 840: When the size of the sub-mesh is greater than the updated encryption threshold, the sub-mesh is divided into sub-mesh segments, and the sub-mesh segmentation operation based on the encryption threshold is continuously executed until the number of segments reaches the preset mesh subdivision threshold.

[0155] This embodiment implements dynamic updating of the encryption threshold and recursively encrypts the grid based on the encryption threshold. By continuously determining the correlation between the grid size and the traversal distance, the grid encryption effect is further improved.

[0156] The meshing threshold can be 5, 6, 7, etc. (representing the maximum number of mesh divisions, such as 5, 6, 7, etc.), and should be determined based on the actual situation. This specification does not impose any limitations. The meshing threshold is set here because the inventors found during experiments that when the mesh is refined to a certain number of times, the improvement in computational accuracy is not significant, but the computational load increases significantly. Therefore, a meshing threshold is set to balance the actual application effect.

[0157] Figure 11 The diagram illustrates the mesh generation process. The center of the large mesh is the initial collision point, and the lower left quarter of the mesh represents the source mesh. Initially, the traversal distance is calculated using the center point of the source mesh as the source term's position. Based on the size of the source mesh and the traversal distance, a decision is made regarding mesh refinement. If refinement is required, the source mesh is decomposed into four sub-meshes by connecting the midpoints of its four sides. The center-to-center distance (the traversal distance between the sub-mesh's center point and the initial collision point) of each newly generated sub-mesh is iteratively determined (i.e., the refinement threshold of the sub-mesh is compared with its size). Based on the determination results, the sub-mesh is further divided until the preset mesh generation threshold is reached. The small black dots in the diagram represent the center points of the sub-meshes.

[0158] Specific experimental data are provided in some embodiments of this specification. Figures 12(a) and 12(b) show schematic diagrams of material distribution in the x,y and x,z planes of space under vacuum boundary conditions, respectively. The horizontal and vertical axes represent the reflection boundaries (considering the case of symmetrical source terms). "Vacuum" represents the vacuum boundary, and "Reflective" represents the reflection boundary. Spatial regions "1", "2", and "3" represent the source term region, the void region, and the shield region, respectively. The corresponding source strength and key material information are shown in Table 1 below. Case 1 represents the case where the particle does not scatter with the shielding material, and case 2 represents the case where the particle scatters with the shielding material with a 50% probability.

[0159] Table 1

[0160]

[0161] In Table 1, the source term is located in region 1, therefore the source strength in region 1 is set to 1 cm. -3 ·s -1 The value in other areas is 0.

[0162] Subsequently, for the calculation of the initial collision source, the mesh-based ray tracing algorithm under unstructured mesh was compared with the ray tracing algorithm based on the geometric model in this scheme. The experimental results are shown in Table 2. The total number of meshes was 215024, the number of meshes in the source region was 253, and the total number of mesh points was 39021. The number of rays to be calculated was: 8 (number of reflections) × 253 (number of source points) × 39021 (number of target mesh points) = 78978504.

[0163] Table 2

[0164] method Ray tracing time / s Count of rays per second Grid-based ray tracing algorithm 12325.0 6408 Ray tracing algorithm based on geometric model 68.4 1154656

[0165] As shown in Table 2, the ray tracing algorithm based on the geometric model (this scheme) takes only 68.4 seconds and can calculate 1,154,656 rays per second, which greatly improves the computational efficiency compared with the mesh-based ray tracing algorithm.

[0166] The angle discretization order is set to S16, the mesh refinement factor of the first collision source is 0.013, and points with XYZ spatial coordinates of (5cm, 5cm, 5cm), (15cm, 15cm, 15cm), ..., (95cm, 95cm, 95cm) are selected as measurement points for comparison with the analytical solution. Figure 13 and Figure 14 These represent the angular flux and maximum relative deviation at each location in scenario case 1. Figure 15 and Figure 16 These represent the angular flux and maximum relative deviation at each location in scenario case2.

[0167] Figures 13 to 16In this diagram, "Flux" represents flux, "Position" represents location, "Ref" represents the reference solution, "FCSOFF" represents the calculation result based on an unstructured mesh without using the first collision source, and "FCS ON" represents the calculation result based on the geometric model with the first collision source. In scenario 1, the maximum relative deviations of "FCS OFF" and "FCS ON" are 132.82% and -13.32%, respectively. In scenario 2, the maximum relative deviations of "FCS OFF" and "FCS ON" are 76.65% and 26.43%, respectively. This demonstrates that the geometric model-based method successfully achieves flux calculation after introducing the first collision source. Furthermore, because this method is based on a geometric model, it significantly reduces computational costs, thus enabling the introduction of the first collision source to improve the accuracy of shielding calculations.

[0168] Figure 17 and Figure 18 The figures show the angular flux distribution of the existing unstructured mesh ray tracing algorithm and the geometric model-based method in scenario case 2, respectively. The darkest color at the bottom represents the source region where the source term is located. It can be seen that... Figure 17 In the source region, there are serrated outward rays, while... Figure 18 In the middle, the transition from the source region to the outer side is smooth, and the ray effect is not obvious.

[0169] Based on the same inventive concept, embodiments of this specification also provide a device for determining the first collision source for shielding calculations, as described in the following embodiments. Since the principle of the device for determining the first collision source for shielding calculations is similar to that of the method for determining the first collision source for shielding calculations, the implementation of the device for determining the first collision source for shielding calculations can refer to the method for determining the first collision source for shielding calculations; repeated details will not be elaborated further.

[0170] Specifically, such as Figure 19 As shown, the device for determining the initial collision source for shielding calculations includes:

[0171] The acquisition module 1910 is used to acquire information about the source term of the emitted particle and information about the preset first collision point of the particle, wherein the preset first collision point represents the position where the particle collides with the matter for the first time during the transport process.

[0172] The first determining module 1920 is used to determine one or more geometric models to characterize the area the particle passes through when it reaches the preset first collision point.

[0173] The second determining module 1930 is used to calculate the travel distance of the particle in each of the geometric models, and determine the first collision source corresponding to the preset first collision point based on the travel distance and the material information corresponding to each of the geometric models.

[0174] The method and apparatus for determining the first collision source for shielding calculations provided in this specification obtain information about the source term of the emitted particle and information about the preset first collision point of the particle to determine the region that the particle passes through when it reaches the preset first collision point. Based on the region it passes through, one or more geometric models representing the region are determined, thereby realizing the direct calculation of the particle's travel distance based on the geometric model, bypassing the continuous mesh, which greatly reduces the computational complexity. Finally, the first collision source is determined based on the travel distance and the material information corresponding to the geometric model, which reduces the cost of shielding calculations.

[0175] It should be noted that the embodiments in this specification achieve the following technical effects:

[0176] (1) Improved computational efficiency. By replacing the traditional mesh traversal algorithm with ray tracing based on the geometric model, the strong correlation between computational cost and mesh density is eliminated, and the complexity of optical distance calculation is reduced (from O(N) to O(1)) in complex geometric scenes, significantly reducing the time consumption of single ray tracing.

[0177] (2) Parallel computing optimization. The domain decomposition parallel architecture, combined with the lightweight geometric model distribution mechanism, breaks through the bottleneck of global data redundancy or high-frequency communication in unstructured grid parallelism, making memory usage and communication overhead independent of the grid encryption scale and maintaining high load balance.

[0178] (3) Optimization of computational accuracy in the near-source region. An adaptive mesh densification strategy based on distance criteria is used to dynamically implement multi-level recursive subdivision in the near-source region (i.e., the mesh region where the source term is located) to achieve a targeted improvement in local accuracy, while avoiding excessive consumption of computational resources by constraining the maximum densification depth.

[0179] (4) Enhanced compatibility with complex geometries. It can efficiently parse geometric models constructed by Boolean operations, avoid discretization errors of structural mesh surfaces, and improve the geometric fidelity of complex assemblies in shielding calculations.

[0180] In one embodiment of this specification, a computer device is also provided for implementing the methods described in any of the above embodiments, such as... Figure 20The diagram illustrates the structure of a computer device according to an embodiment of this specification. The computer device 2002 may include one or more processors 2004, such as one or more central processing units (CPUs), each of which can implement one or more hardware threads. The computer device 2002 may also include any memory 2006 for storing information of any kind, such as code, settings, data, etc. Non-limitingly, for example, the memory 2006 may include any type of RAM, any type of ROM, flash memory, hard disk, optical disk, etc. More generally, any memory can use any technology to store information. Furthermore, any memory can provide volatile or non-volatile retention of information. Furthermore, any memory can represent a fixed or removable component of the computer device 2002. In one case, when the processor 2004 executes associated instructions stored in any memory or combination of memories, the computer device 2002 can perform any operation of the associated instructions. The computer device 2002 also includes one or more drive mechanisms 2008 for interacting with any memory, such as hard disk drive mechanisms, optical disk drive mechanisms, etc.

[0181] Computer device 2002 may also include an input / output module 2010 (I / O) for receiving various inputs (via input device 2012) and providing various outputs (via output device 2014). A specific output mechanism may include a presentation device 2016 and an associated graphical user interface (GUI) 2018. In other embodiments, the input / output module 2010 (I / O), input device 2012, and output device 2014 may be omitted, and the device may function solely as a computer device within a network. Computer device 2002 may also include one or more network interfaces 2020 for exchanging data with other devices via one or more communication links 2022. One or more communication buses 2024 couple the components described above together.

[0182] Communication links 2022 can be implemented in any way, such as via a local area network (LAN), a wide area network (WAN) (e.g., the Internet), a point-to-point connection, or any combination thereof. Communication links 2022 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0183] Corresponding to Figures 1 to 8 In addition to the methods described above, embodiments of this specification also provide a computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the methods described above.

[0184] This specification also provides computer-readable instructions, wherein when a processor executes the instructions, the program therein causes the processor to perform the following... Figures 1 to 8 The method shown.

[0185] It should be understood that in the various embodiments of this specification, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this specification.

[0186] It should also be understood that, in the embodiments of this specification, the term "and / or" 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, and B existing alone. Additionally, the character " / " in this specification generally indicates that the preceding and following related objects have an "or" relationship.

[0187] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this specification can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the embodiments in this specification.

[0188] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0189] In the several embodiments provided in this specification, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through some interfaces, devices, or units, or they may be electrical, mechanical, or other forms of connection.

[0190] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments described in this specification, depending on actual needs.

[0191] Furthermore, the functional units in the various embodiments of this specification can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0192] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this specification, in essence, or the parts that contribute to the prior art, or all or part of the technical solutions, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this specification. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0193] This specification uses specific embodiments to illustrate the principles and implementation methods of this specification. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of the embodiments in this specification. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the embodiments in this specification. Therefore, the content of this specification should not be construed as a limitation on the embodiments in this specification.

Claims

1. A method for determining the initial collision source for shielding calculations, characterized in that, The method includes: Acquire information about the source term of the emitted particle and information about the preset first collision point of the particle, wherein the preset first collision point represents the position where the particle collides with the matter for the first time during the transport process; Based on the area that the particle passes through when it reaches the preset first collision point, determine one or more geometric models to characterize the area it passes through; The distance the particle travels through each of the geometric models is calculated, and based on the travel distance and the material information corresponding to each geometric model, the first collision source corresponding to the preset first collision point is determined.

2. The method as described in claim 1, characterized in that, Before obtaining information about the source term of the emitted particle and the preset first collision point of the particle, the process also includes: Construct a total mesh region containing the preset first collision point and the source item; Generate a set of geometric models corresponding to the total grid region; Based on each computing core and the total grid area, the grid area responsible for each computing core is determined; The source item information, the set of geometric models and corresponding material information, and the mesh regions responsible for each computing core are sent to the corresponding computing core.

3. The method as described in claim 2, characterized in that, Calculating the distance the particle travels in each of the geometric models includes: Based on the information of the source term and the information of the preset first collision point, the entry and exit positions of the particle in each of the geometric models are determined; Each computing core calculates the travel distance of the particle corresponding to different first collision points in parallel based on the entry position and the exit position.

4. The method as described in claim 1, characterized in that, Based on the travel distance and the material information corresponding to each geometric model, the first collision source corresponding to the preset first collision point is determined, including: Based on the distance the particle travels in each of the geometric models, the total distance the particle travels corresponding to the same material information is determined; Obtain the total cross-section of the geometric model with the same material information; The optical distance of the particle is determined based on the total travel distance and total cross-section of the particle in different materials; Based on the optical distance, the first collision source corresponding to the preset first collision point is determined.

5. The method as described in claim 1, characterized in that, The method further includes: Obtain information about the reflection boundary; Construct a virtual source term that is symmetric about the reflection boundary and about the source term; Based on the virtual source item and the preset first collision point, determine the intersection point of the travel path of the emitted particles of the virtual source item and the reflection boundary; The travel distance of the emitted particles of the virtual source item in each of the geometric models is determined based on the area traversed by the emitted particles after they are emitted and reach the preset first collision point via the intersection point.

6. The method as described in claim 2, characterized in that, The method further includes: The encryption threshold is determined based on the preset mesh refinement factor and the particle travel distance between the source term and the preset first collision point; Encrypt the grid of the grid region containing the source item based on the encryption threshold; Based on the travel distance, the grid and material information of the grid region where the source item is located, the first collision source corresponding to the preset first collision point is determined.

7. The method as described in claim 6, characterized in that, The grid of the grid region containing the source item is encrypted according to the encryption threshold, including: Determine whether the size of the grid in the grid region where the source item is located is greater than the encryption threshold; If the determination is yes, recursively encrypt the grid in the grid region where the source term is located.

8. The method as described in claim 7, characterized in that, Recursively refine the mesh of the mesh region containing the source term, including: Divide the grid region containing the source term into sub-grids; Calculate the distance between the center distance of the sub-mesh and the preset first collision point; The encryption threshold is updated based on the preset mesh refinement factor and the distance between the center distance of the sub-mesh and the preset first collision point. When the size of a sub-mesh is greater than the updated encryption threshold, the sub-mesh is divided into sub-mesh sections, and the sub-mesh division operation based on the encryption threshold is continuously performed until the number of divisions reaches the preset mesh partitioning threshold.

9. A device for determining the initial collision source for shielding calculations, characterized in that, The device includes: The acquisition module is used to acquire information about the source term of the emitted particle and information about the preset first collision point of the particle, wherein the preset first collision point represents the position where the particle collides with the matter for the first time during the transport process. The first determining module is used to determine one or more geometric models to characterize the area that the particle passes through when it reaches the preset first collision point. The second determining module is used to calculate the travel distance of the particle in each of the geometric models, and determine the first collision source corresponding to the preset first collision point based on the travel distance and the material information corresponding to each of the geometric models.

10. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method according to any one of claims 1 to 8.

11. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor of a computer device, it implements the method of any one of claims 1 to 8.

12. A computer program product, the computer program product comprising a computer program, characterized in that, When the computer program is executed by the processor of a computer device, it implements the method of any one of claims 1 to 8.

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