A material radiation damage simulation calculation method and calculation device

Abstract

A method for simulating and calculating material radiation damage calculates the angular flux function of irradiated particles and uses this angular flux function to simulate the primary dissociated atomic states of different elements within the target material under irradiation, thereby obtaining the spatial distribution of maximum radiation damage and establishing a functional relationship between the spatial distribution of radiation damage and the transport distance of the irradiated particles. A finite element model of the target material is established, and the radiation source distribution and source intensity are defined within the finite element model. The radiation damage state within each finite element is calculated, thereby obtaining the spatial distribution of radiation damage within the target material model. This method can accurately simulate the radiation damage behavior of materials with multiphase and polycrystalline structures, improving the accuracy of nuclear engineering safety assessments. The present invention also provides a calculation device.

Description

Technical Field

[0001] The present invention belongs to the field of nuclear engineering, and in particular relates to a material radiation damage simulation calculation method and a calculation device. Background Art

[0002] In nuclear engineering, atomic dislocation is the primary form of radiation damage to materials. This occurs when an incident particle knocks an atom out of its original lattice site. Dislocated atoms are typically caused by radiation from heavy charged particles, such as alpha particles or protons, or neutrons. A single alpha particle or neutron can often generate hundreds of dislocated atoms. Under high-intensity, long-term radiation exposure, material properties can be significantly affected. Therefore, evaluating and predicting the effects of radiation damage on materials is crucial for the safety and reliability of nuclear engineering construction. Currently, analytical simulations of radiation damage to materials are typically based on homogeneous material models. For example, SRIM / TRIM software can only simulate the transport and radiation damage caused by heavy charged particles, while Monte Carlo methods can simulate the transport and radiation damage of multiple particles, but neither method can reflect multiphase unit cell structures with specific geometries. However, many materials used in nuclear engineering are multiphase, inhomogeneous materials, such as ceramic solids of nuclear waste. Existing technologies struggle to accurately simulate and predict the radiation damage behavior of these materials. Therefore, an improved radiation damage simulation calculation method is provided to simulate the radiation damage behavior of multiphase inhomogeneous materials, which has high practical value. Summary of the Invention

[0003] The present invention aims to provide a material radiation damage simulation calculation method to improve the simulation accuracy of radiation damage behavior of multi-phase inhomogeneous materials. The present invention also provides a calculation device.

[0004] According to an embodiment of one aspect of the present invention, a method for simulating and calculating material radiation damage is provided, the method comprising the following steps:

[0005] Providing a target material model, wherein the target material model is a finite element model and includes a unit cell structure and components of the target material;

[0006] Establishing an irradiated particle transport model to calculate the angular flux function of the irradiated particles and / or primary dissociated atoms generated by the irradiated particles at various positions within the homogeneous material;

[0007] Calculating the maximum radiation damage that can be caused by the irradiated particles or the primary dislocated atoms generated by the irradiated particles at different energies and incident angles, and combining the above-mentioned angular flux function information to obtain the spatial distribution of the maximum radiation damage caused by the primary dislocated atoms in the homogeneous material;

[0008] performing differential solution on a calculation result of the spatial distribution of the maximum radiation damage caused by the irradiated particles to obtain a function of the radiation damage density with respect to the transport distance of the irradiated particles;

[0009] The radiation source distribution and source intensity in the target material model are defined, and the out-of-situ atomic data in each finite element model are calculated based on the function of the radiation damage density with respect to the irradiated particle transport distance to obtain the geometric distribution of the radiation damage in the material model.

[0010] Using the above method, it is possible to simulate and calculate the radiation damage behavior of inhomogeneous materials such as polycrystalline alloys, ceramic materials, or metal-ceramic composites. The calculation model is more consistent with actual scenarios such as nuclear waste ceramic solid bodies.

[0011] Furthermore, in some embodiments, the target material model is generated under the MOOSE framework.

[0012] Furthermore, in some embodiments, the target material model is configured as a mesoscale 2D or 3D model, and the generation method includes random generation and generation based on experimental data such as EBSD data.

[0013] Furthermore, in some embodiments, the irradiating particles include alpha particles, heavy charged particles such as protons, and / or neutrons. This method can accurately analyze and simulate the radiation damage behavior under mixed radiation sources.

[0014] Furthermore, in some embodiments, the energy and recoil angle function of the primary delocalized atom is described by an angular flux function.

[0015] Furthermore, in some embodiments, the maximum radiation damage caused by the primary ex-situ atoms in the homogeneous material is calculated using the SRIM / TRIM program, arc-dpa model, NRT model or molecular dynamics method.

[0016] Furthermore, in some embodiments, the maximum radiation damage is characterized by the number of atomic dissociations.

[0017] Furthermore, in some embodiments, the target material model is configured as a single-phase or multi-phase polycrystalline material model and includes metal material grains and / or ceramic material grains.

[0018] According to another embodiment of the present invention, a computing device is provided, which includes a memory and a processor, wherein the memory stores a computing program, and when the computing program is executed by the processor, the radiation damage simulation calculation method provided in any of the aforementioned embodiments can be implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1This is a flow chart of a method for simulating and calculating radiation damage in one embodiment;

[0020] Figure 2 is an image of the spatial angular flux function of α particles in one embodiment;

[0021] Figure 3 is a spatial distribution image of the maximum radiation damage that can be caused by α particles in one embodiment;

[0022] Figure 4 FIG1 is a graph showing the function of irradiation damage density with respect to transport distance in one embodiment;

[0023] Figure 5 Schematic diagram of the geometric distribution of radiation damage in one embodiment.

[0024] The purpose of the above drawings is to provide a detailed description of the present invention so that those skilled in the art can understand the technical concept of the present invention, and is not intended to limit the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below through specific embodiments with reference to the accompanying drawings.

[0026] Reference to "embodiments" herein means that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment herein. The phrases appearing in various locations in the specification do not necessarily refer to the same embodiment, nor are they limited to mutually exclusive independent or alternative embodiments. It should be understood by those skilled in the art that the embodiments herein may be combined with other embodiments without causing structural conflicts. In the description herein, "a plurality" means at least two.

[0027] Currently, conventional methods for analyzing material radiation damage have limitations. For example, SRIM / TRIM software can only simulate the transport and resulting damage of heavily charged particles in homogeneous materials (single phases). It cannot simulate multiphase unit cell structures with irradiated geometries, nor can it simulate the irradiation damage caused by uncharged neutrons. Conventional Monte Carlo methods, while capable of simulating the transport and resulting damage of multiple particles, are similarly limited to homogeneous materials and cannot simulate multiphase polycrystalline materials with irradiated geometries. In nuclear engineering applications, components such as nuclear waste ceramic solids are multiphase polycrystalline materials. Their damage behavior under long-term irradiation, such as irradiation swelling, irradiation hardening, embrittlement, changes in thermal conductivity, and elemental segregation, is difficult to simulate and predict using existing techniques. This hinders safety and reliability assessments in nuclear engineering and hinders the widespread application of civilian nuclear technology.

[0028] In order to solve the above problems, an embodiment of one aspect of the present invention provides an irradiation simulation damage calculation method, which can simulate the number of dislocated atoms generated when neutrons or heavy charged particles (such as α particles) hit the material and their geometric distribution in the material. Figure 1 As shown, the method includes the following steps:

[0029] a) Calculate the angular flux function of the incident particles and / or the primary off-position atoms generated by the incident particles at different positions in the material, that is, the spatial distribution of the angular flux of the incident particles in the homogeneous material. Wherein, the homogeneous material refers to a uniform atomic array of the same phase, wherein the non-uniform structures such as grain boundaries, phase interfaces, twins, subgrain boundaries and dislocations are not considered. Depending on the difference of the incident particles, a simulation calculation program is established for the transport process of neutrons or charged heavy ions (such as α particles or protons) or an existing particle transport program is used to calculate the angular flux function J (E, Ω, x). Wherein J is the angular flux, E is the energy of the particle, Ω is the angle of the particle, and x is the spatial position of the particle in the material.

[0030] b) Establish a functional relationship between the radiation damage caused by the incident particle in the material and the angle and energy of the incident particle. Use the NRT model, arc-dpa model, molecular dynamics (MD) simulation program, or SRIM / TRIM program to evaluate the maximum radiation damage (represented by the number of atomic dissociations) D(E,Ω) that the incident particle can cause after reaching a certain position x in the homogeneous material. When the incident particle is a neutron and the material is a mixed material, it is necessary to first obtain the energy and recoil angle of the primary dissociated atoms through a neutron transport program, and then add the maximum radiation damage that these primary dissociated atoms can cause to obtain the maximum radiation damage function that the neutron can cause after reaching position x in the material.

[0031] c) Establish a functional relationship between the radiation damage caused by the incident particles in the material and the transport distance. The functional relationship in step a) and step b) is coupled by the following equation to obtain the maximum number of atomic dissociations D that the incident particles can cause at each position in the material: tot :

[0032]

[0033] Differentiating the above formula yields the local radiation damage density function caused by the incident particles at each position in the material, that is, the function of the radiation damage density with respect to the transport distance.

[0034] d) Establish a data set for assessing the degree of radiation damage to materials. A 2D or 3D target material model at a mesoscale is established by a finite element program (MOOSE framework is used in a preferred embodiment). In different embodiments, the target material model can be randomly generated or established based on actual experimental (such as backscattered electron diffraction, EBSD) data and defines the area in which the radiation source is generated. In some embodiments, the radiation source for nuclear waste ceramic solid bodies is located inside the material. In other embodiments, the radiation source for nuclear waste sealed cladding is located on the surface of the material. Based on the local radiation damage density function obtained in step c), a data set for assessing the degree of radiation damage to materials is established. When dividing the finite element, the materials in the same finite element should belong to the same phase, and there should be no grain boundaries, subgrain boundaries or twin boundaries in a finite element that affect the uniformity of the material; for structures such as phase interfaces, grain boundaries, subgrain boundaries, twin boundaries, etc., finite element division should be performed separately.

[0035] e) Calculating irradiation damage and damage distribution: Based on the function of irradiation damage density with respect to transport distance obtained in step c) and the target material model established in step d), calculations are performed on each finite element to determine the degree of irradiation damage in the material and its spatial distribution.

[0036] The above method can be used to simulate and calculate the radiation damage of heterogeneous materials, especially polycrystalline materials with multiple phase compositions. It can also simulate mixed sources of neutrons and baryons. The simulation results are presented in the form of geometric distribution of radiation damage, which is more intuitive and reliable.

[0037] In the first embodiment, the radiation damage of the solidified ceramic body of the Dutch stone phase nuclear waste under the influence of α-particle irradiation is simulated and calculated, and the process is as follows:

[0038] First, the α-particle transport model was established, and the heavy charged particle transport program was used to calculate the angular flux function of α-particles at various positions in the uniform Dutch stone phase. The angular flux function image at one position is shown in the figure below. Figure 2 shown.

[0039] Next, the TRIM program is used to calculate the maximum radiation damage that can be caused by α particles at different energies E and angles Ω (by the number of dislocated atoms D generated). tot Characterization), and combined with the angular flux function to calculate the spatial distribution of the maximum radiation damage caused by α particles, the results are as follows Figure 3 shown.

[0040] Next, the spatial distribution of the maximum radiation damage caused by α particles is differentiated to obtain the function of radiation damage density with respect to the transport distance. The function graph is as follows: Figure 4 shown.

[0041] In the MOOSE framework, a mesoscale 2D geometric model of a nuclear waste ceramic solid body is randomly generated, and the material composition, α source (radioactive Pu isotope) distribution, and source intensity are defined in the unit cell. Based on the function of the irradiation damage density with respect to the transport distance, the distance between each finite element and other finite elements containing radioactive Pu isotopes is calculated, and the results are summed to calculate the order of magnitude of dislocated atoms generated by α particle irradiation in each finite element, and then the geometric distribution of irradiation damage in the 2D model of the nuclear waste ceramic solid body is obtained, such as Figure 5 As shown, the highlighted grid area 1 is the location of the defined α source.

[0042] In the second embodiment, the simulation calculation process of neutron irradiation damage of a nuclear waste ceramic solidified body containing Dutchmanite phase and pyroxenite phase is as follows:

[0043] First, a neutron transport model is established, and the angular flux function of neutrons at various positions in the material is calculated using a neutron transport program.

[0044] The angular flux function information is used to calculate the energy and recoil angle of primary dissociated atoms under neutron irradiation conditions in each phase of nuclear waste ceramic solidification body (described by angular flux function).

[0045] Next, the NRT model is used to calculate the maximum radiation damage D that can be caused by primary delocalized atoms at different positions at different energies E and angles Ω. tot , and perform differential solution to obtain the function of radiation damage density with respect to transport distance.

[0046] Within the MOOSE framework, a mesoscale 2D geometric model is established using experimental data from backscattered electron diffraction (EBSD) of ceramic solids, and the atomic species and distribution within each unit cell, as well as the neutron source distribution and source intensity, are defined based on experimental or theoretical predictions.

[0047] Next, the distance between each finite element and other finite elements containing the neutron source is calculated separately, and the results are summed to obtain the order of magnitude of dislocated atoms caused by neutron radiation in each finite element, and then the geometric distribution of radiation damage in the 2D model of the nuclear waste ceramic solid body is obtained.

[0048] Using EBSD test data for finite element modeling can improve the accuracy of simulation results.

[0049] In the third embodiment, the simulation calculation process of neutron irradiation damage of a pure metal material is as follows:

[0050] First, a neutron transport model is established, and the angular flux function of neutrons at various positions in the material is calculated using a neutron transport program.

[0051] The angular flux function is used to calculate the energy and recoil angle of primary dissociated atoms under neutron irradiation conditions of atoms of various elements in the uniform structure of metal materials (described by the angular flux function).

[0052] Next, the molecular dynamics (MD) method is used to calculate the maximum radiation damage D that can be caused by the primary dissociated atoms at each position under different energies E and incident angles Ω. tot , and perform differential solution to obtain the function of radiation damage density with respect to transport distance.

[0053] In the MOOSE framework, the EBSD test data of metal material samples are used to establish a mesoscale 2D geometric model, and the atomic types and distribution within each unit cell as well as the neutron source distribution and source intensity are defined.

[0054] Finally, the distance between each finite element and other finite elements containing the neutron source is calculated respectively, and the results are summed to obtain the order of magnitude of dislocated atoms caused by neutron radiation in each finite element, and then the geometric distribution of radiation damage in the 2D model of the metal material is obtained.

[0055] The MD method is used for simulation calculations, which can incorporate complex structures such as dislocations and grain boundaries in metal crystals, as well as interactions between atoms and thermodynamic and kinetic effects into the simulation calculations, thereby further improving the accuracy of the simulation results.

[0056] In the fourth embodiment, the simulation calculation process of neutron irradiation damage of an alloy material is as follows:

[0057] First, a neutron transport model is established, and the angular flux function of neutrons at various positions in the material is calculated using a neutron transport program.

[0058] The angular flux function is used to calculate the energy and recoil angle of primary dissociated atoms under neutron irradiation conditions for each element in the uniform structure of the alloy material (described by the angular flux function). When multiple phases exist in the alloy material, the calculation is performed separately for each phase.

[0059] Next, the molecular dynamics (MD) method is used to calculate the maximum radiation damage D that can be caused by the primary dissociated atoms at each position under different energies E and incident angles Ω. tot , and perform differential solution to obtain the function of radiation damage density with respect to transport distance.

[0060] Within the MOOSE framework, EBSD test data from metallic samples is used to establish a mesoscale 2D geometric model, defining the atomic species and distribution within each unit cell, as well as the neutron source distribution and intensity. In some embodiments, when the simulation object is a solid-solution alloy without considering segregation, the atomic species and distribution within each unit cell can be assumed to be identical. When the simulation object is a multiphase alloy, the atomic species and distribution within each unit cell are included, including both the matrix unit cell and the precipitated phase unit cell.

[0061] Finally, the distance between each finite element and other finite elements containing the neutron source is calculated respectively, and the results are summed to obtain the order of magnitude of dislocated atoms caused by neutron radiation in each finite element, and then the geometric distribution of radiation damage in the 2D model of the metal material is obtained.

[0062] The MD method is used for simulation calculations, which can incorporate complex structures such as dislocations and grain boundaries in alloy crystals, as well as the interactions between atoms and thermodynamic and kinetic effects into the simulation calculations, thereby further improving the accuracy of the simulation results.

[0063] In the fifth embodiment, the simulation calculation process of the damage of a nuclear waste ceramic solidified body caused by mixed neutron and α particle irradiation is as follows:

[0064] Firstly, the neutron and α particle transport models are established respectively, and the angular flux functions of neutrons and α particles at various positions in the material are calculated using the neutron and charged baryon transport program.

[0065] The angular flux function is used to calculate the energy and recoil angle of neutrons on primary dissociated atoms in uniform tissue in ceramic solidification under irradiation conditions (described by the angular flux function).

[0066] Next, the molecular dynamics (MD) method is used to calculate the maximum radiation damage that can be caused by the primary dissociated atoms of neutrons at various positions at different energies and incident angles. The TRIM program is used to calculate the maximum radiation damage that can be caused by α particles at various energies and angles. The maximum radiation damage caused by neutrons and α particles is added together to obtain the mixed radiation damage D. tot And perform differential solution to obtain the function of radiation damage density with respect to transport distance.

[0067] In the MOOSE framework, the EBSD test data of ceramic solid material samples are used to establish a mesoscale 2D geometric model, and the atomic species, distribution, mixed irradiation source distribution and source intensity in each unit cell are defined.

[0068] Finally, the distance between each finite element and other finite elements containing the neutron source is calculated separately, and the results are summed to obtain the order of magnitude of dislocated atoms caused by neutron radiation in each finite element, and then the geometric distribution of radiation damage in the 2D model of the ceramic solid body is obtained.

[0069] The above method can accurately simulate the radiation damage behavior caused by mixed radiation sources.

[0070] The material irradiation damage simulation calculation method provided in the above embodiment can be implemented by the computing device provided in the embodiment of another aspect of the present invention. The computing device includes a memory and a processor, and a computing program is stored in the memory. When the computing program is executed by the processor, the irradiation material damage simulation calculation method provided in the above embodiment can be implemented. The computing device can be a general-purpose computer, or a specially built dedicated computing device, or a computing device with equivalent functions such as a cloud computing device or a computing server. The simulation and calculation processes involved in each step in the above embodiment can be implemented using a general-purpose simulation computing program, or can be implemented by a specially written dedicated computing program, or can be implemented in a general-purpose computing program through a specially written script.

[0071] According to the principles of the material radiation damage simulation calculation method provided in the above embodiment, it can be understood that the above method is not limited to simulating the radiation damage behavior of multi-phase polycrystalline materials. In other embodiments, the finite element method can also be used to simulate and calculate the radiation damage behavior of other materials such as uniform materials or amorphous materials.

[0072] The purpose of the above embodiments is to provide a further detailed description of the present invention in conjunction with the accompanying drawings so that those skilled in the art can understand the technical concept of the present invention. Within the scope of the present invention, optimization or equivalent replacement of the method steps and device components involved, as well as combination of implementation methods in different embodiments without causing structural or principle conflicts, all fall within the scope of protection of the present invention.

Claims

1. A material radiation damage simulation calculation method, characterized in that: The following steps are involved: Providing a target material model, wherein the target material model is a finite element model and includes a unit cell structure and components of the target material; Establishing an irradiated particle transport model to calculate the angular flux function of the irradiated particles and / or primary dissociated atoms generated by the irradiated particles at various positions within the homogeneous material; Calculating the maximum radiation damage that can be caused by the irradiated particles or the primary displaced atoms generated by the irradiated particles at different energies and incident angles, and combining the above-mentioned angular flux function information to obtain the spatial distribution of the maximum radiation damage caused by the irradiated particles in the uniform material; performing differential solution on a calculation result of the spatial distribution of the maximum radiation damage caused by the irradiated particles to obtain a function of the radiation damage density with respect to the transport distance of the irradiated particles; The radiation source distribution and source intensity in the target material model are defined, and the out-of-place atomic data in each finite element are calculated according to the function of the radiation damage density with respect to the transport distance to obtain the geometric distribution of the radiation damage in the material model.

2. The radiation damage simulation calculation method according to claim 1, characterized in that: The target material model is generated under the MOOSE framework.

3. The radiation damage simulation calculation method according to claim 2, characterized in that: The target material model is configured as a mesoscale 2D or 3D model, and the generation method includes random generation and generation based on EBSD data.

4. The radiation damage simulation calculation method according to claim 1, 2 or 3, characterized in that: The irradiating particles include heavy charged particles and / or neutrons.

5. The radiation damage simulation calculation method according to claim 1, 2 or 3, characterized in that: The energy and recoil angle function of the primary dissociated atom is described by the angular flux function.

6. The radiation damage simulation calculation method according to claim 1, 2 or 3, characterized in that: The spatial distribution of the maximum radiation damage caused by the primary displaced atoms in the homogeneous material is calculated by SRIM or TRIM program, arc-dpa model, NRT model or molecular dynamics method.

7. The radiation damage simulation calculation method according to claim 1, 2 or 3, characterized in that: The maximum radiation damage is characterized by the number of atomic dissociations.

8. The radiation damage simulation calculation method according to claim 1, 2 or 3, characterized in that: The target material model is configured as a single-phase or multi-phase polycrystalline material model and includes metal material grains and / or ceramic material grains.

9. A computing device comprising a memory and a processor, characterized in that: The memory stores a calculation program, and when the calculation program is executed by the processor, the radiation damage simulation calculation method according to any one of claims 1 to 8 can be implemented.

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