A method, system and medium for seismic analysis of a fast reactor full core assembly

Abstract

The present invention relates to a method, system and medium for seismic analysis of a fast reactor full core assembly. The method comprises: equivalently decomposing the full reactor nonlinear multi-component system into a series of linear single-component vibration systems; calculating the additional mass coefficient of the characteristic component based on numerical simulation to simulate the influence of fluid-solid coupling on the vibration of the component; establishing a finite beam unit model of a single core assembly that is independent of each other based on Euler-Bernoulli theory, connectors and additional mass coefficients; reducing the dimension of the single core assembly vibration system to a solution of a single degree of freedom system; calculating the vibration response of the single degree of freedom system in modal coordinates using a central difference method and converting it into a dynamic response in physical coordinates; and performing deflection analysis and contact analysis if the earthquake acceleration time history stops. The present invention rapidly solves the structural dynamic response under gap conditions, greatly improving the computational efficiency of the method.

Description

Technical Field

[0001] The present invention relates to the technical field of seismic assessment of fast reactor core structures, and in particular to a seismic analysis method, system, and medium for a fast reactor full core assembly. Background Art

[0002] A typical fast reactor core is composed of hundreds of core assemblies arranged in a hexagonal pattern and independently inserted into the core support structure. The gaps between adjacent assemblies are very small, only a few millimeters, making collisions between adjacent assemblies inevitable during earthquakes. Furthermore, because all core assemblies are inserted and connected to supports and surrounded by fluid, the core assembly vibrates as a whole, creating significant fluid-structure coupling issues and further complicating internal collisions. When the intensity of an earthquake increases, excessive deformation and impact forces from the assemblies can affect the insertion and removal of control rods, leading to strength failure of the core assembly and even the risk of nuclear leakage, compromising the safety and reliability of the reactor. Therefore, the development of core seismic analysis and assessment methods is essential for fast reactor core design.

[0003] In order to evaluate the vibration characteristics of large-scale fast reactor core components, the main evaluation methods currently include: seismic tests and finite element seismic analysis methods. Although seismic tests are more reliable, due to the high cost of the tests, complete full-scale core seismic tests are rarely carried out. In order to solve this problem, equivalent alternatives are usually adopted, such as single component tests, single row component tests, hexagonal array component tests, and scaled tests. Compared with traditional seismic tests, finite element seismic analysis methods are more economical and efficient. The current common methods include numerical simulation (ABAQUS\ANASYS, etc.) and independently developed methods, such as France's CAST3M and Japan's REVIAN-3D methods. Although the above methods have greatly promoted the evaluation of the seismic performance of reactors, there are still some defects, which are mainly reflected in the following aspects:

[0004] Test plan: Although the alternative test plan has simulated the real component vibration environment as much as possible, there are still many differences between the test setup and the real environment, such as the boundary conditions of the entire core, the influence of fluids, and scale effects.

[0005] Numerical simulation solution: To simulate the seismic response of the entire core assembly, traditional finite element software usually requires a large amount of computing time and memory, and has high requirements for computer hardware and software environment.

[0006] Seismic analysis methods: Seismic analysis methods independently developed by various countries mainly use the direct time integration method or corresponding improved versions, which have relatively low computational efficiency. Currently, the above-mentioned seismic analysis mainly focuses on deformation and displacement response analysis, and lacks in-depth research.

[0007] How to fully consider the actual working conditions of the components in the core when they vibrate, improve computing efficiency and reduce the computing environment is an urgent problem that needs to be solved. Summary of the Invention

[0008] The present invention provides a method, system and medium for seismic analysis of a fast reactor full core assembly, in order to solve the problem of high requirements on computer hardware and software environment and relatively low calculation efficiency.

[0009] To achieve the above objectives, in a first aspect, the present invention provides a method for seismic analysis of a fast reactor core assembly, which is used for seismic analysis and calculation of the core assembly of a fast reactor core during a seismic acceleration time history. Spacers are provided between the core assemblies, the core assemblies are fixed by pins inserted into sockets, and spherical supports provide unilateral positional limitation for the core assemblies, comprising:

[0010] Step 1: Based on numerical simulation, a gap-damper-spring connector for simulating nonlinear collision of core components is obtained. The motion state of each core component and the contact state of each connector are initialized to obtain a full-core nonlinear multi-component system. The full-core nonlinear multi-component system is equivalently decomposed into a series of linear single-component vibration systems.

[0011] Step 2: Calculate the natural frequency and corresponding mode shape of the selected characteristic component, and calculate the added mass coefficient of the characteristic component based on numerical simulation to simulate the effect of fluid-structure interaction on the component vibration;

[0012] Step 3: Based on the Euler-Bernoulli theory, an equivalent beam model of the core assembly is constructed. In combination with the connector and the additional mass coefficient, a finite beam unit model of a single core assembly that is independent of each other is established. The connector is respectively provided between the core assembly and the core assembly spacer, between the core assembly and the spherical support, and between the pin and the socket.

[0013] Step 4: Reduce the dimension of the single core assembly vibration system to a single degree of freedom system;

[0014] Step 5: Calculate the vibration response of the single-degree-of-freedom system in modal coordinates using the central difference method, and convert the vibration response into a dynamic response in physical coordinates;

[0015] Step 6: Determine whether the earthquake acceleration time history stops. If the earthquake acceleration time history stops, perform deflection analysis and contact analysis.

[0016] Preferably, after determining whether the earthquake acceleration time history has stopped, the method further includes, if the earthquake acceleration time history has not stopped, repeating steps three to five in sequence.

[0017] To achieve the above objectives, in a second aspect, a method for performing seismic analysis and calculation of core assemblies of a fast reactor core during a seismic acceleration time history is provided, wherein spacers are provided between the core assemblies, the core assemblies are fixed by inserting pins into sockets, and spherical supports provide unilateral positional limitation for the core assemblies, including:

[0018] a single-component vibration system generation module, configured to obtain, based on numerical simulation, a gap-damper-spring connector for simulating nonlinear collisions of core components, initialize the motion state of each core component and the contact state of each connector, obtain a full-core nonlinear multi-component system, and decompose the full-core nonlinear multi-component system into a series of linear single-component vibration systems;

[0019] An additional mass coefficient calculation module is used to calculate the natural frequency and corresponding mode shape of the selected characteristic component, and based on numerical simulation, calculate the additional mass coefficient of the characteristic component to simulate the influence of fluid-structure interaction on the vibration of the component;

[0020] an equivalent beam model construction module, configured to construct an equivalent beam model of the core assembly based on the Euler-Bernoulli theory, and to establish an independent finite beam unit model of a single core assembly in combination with the connector and the additional mass coefficient, wherein the connector is respectively provided between the core assembly and the core assembly spacer, between the core assembly and the spherical support, and between the pin and the socket;

[0021] A dimensionality reduction module, used to reduce the dimension of the single core assembly vibration system to a single degree of freedom system solution;

[0022] A physical response module, configured to calculate the vibration response of the single-degree-of-freedom system in modal coordinates using a central difference method, and convert the vibration response into a dynamic response in physical coordinates;

[0023] The time judgment module is used to judge whether the earthquake acceleration time history has stopped, and if the earthquake acceleration time history has stopped, perform deflection analysis and contact analysis.

[0024] To achieve the above objectives, in a third aspect, the present invention further relates to a computer-readable storage medium having instructions stored therein, which, when executed, execute the above-mentioned method for seismic analysis of a full core assembly of a fast reactor.

[0025] The present invention relates to a method, system, and medium for seismic analysis of a fast reactor full core assembly. Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention fully considers the actual working conditions of components in the core when they vibrate: nonlinear collision, fluid-solid coupling problems and computational efficiency issues, proposes a simplified beam unit model, uses a gap-damper-spring connector to simulate the nonlinear collision between components and components and between components and the shroud, simplifies the influence of fluid-solid coupling to the additional mass of the components, and improves the traditional modal superposition method to accelerate the solution of dynamic response under gap nonlinear conditions, making it more applicable to engineering projects.

[0027] The present invention decomposes complex nonlinear systems into equivalent linear systems for calculation, improves the traditional modal superposition method, quickly solves the structural dynamic response under gap conditions, abandons the traditional direct time integration method of large-scale nonlinear systems, and greatly improves the computational efficiency of the method. Therefore, it will have broad application prospects in the field of seismic analysis of fast reactor core components. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of a method for seismic analysis of a fast reactor full core assembly in Example 1 of the present invention;

[0029] Figure 2 This is a schematic diagram of the main process of a method for seismic analysis of a full core assembly of a fast reactor in Example 1 of the present invention;

[0030] Figure 3 This is a schematic diagram of calculating the fluid-solid coupling additional mass coefficient of a core assembly in a method for seismic analysis of a full core assembly of a fast reactor in Example 1 of the present invention;

[0031] Figure 4 This is a schematic diagram of a Central European Bernoulli beam element for a method for seismic analysis of a full core assembly of a fast reactor in Example 1 of the present invention;

[0032] Figure 5 Schematic diagram of a collision model used in a method for seismic analysis of a full core assembly of a fast reactor in Example 1 of the present invention;

[0033] Figure 6 This is a schematic diagram of a simplified beam unit model of a core assembly in a method for seismic analysis of a full core assembly of a fast reactor in Example 1 of the present invention;

[0034] Figure 7 Schematic diagram of an improved modal superposition method for seismic analysis of a fast reactor full core assembly in Example 1 of the present invention;

[0035] Figure 8 Schematic diagram of earthquake acceleration of Example 1 and Example 2 in Example 1 of the present invention;

[0036] Figure 9 The figure is a comparison of the calculation results of the seismic analysis method proposed by the present invention and the finite element software ABAQUS in Example 1 of the embodiment of the present invention;

[0037] Figure 10 This is a schematic diagram of the deflection analysis results of the top of the component of Example 2 of Example 1 of the present invention. Figure 1 ;

[0038] Figure 11 This is a schematic diagram of the deflection analysis results of the top of the component of Example 2 of Example 1 of the present invention. Figure 2 ;

[0039] Figure 12 This is a schematic diagram of the deflection analysis results of the top of the component of Example 2 of Example 1 of the present invention. Figure 3 ;

[0040] Figure 13 This is a schematic diagram of the deflection analysis results of the top of the component of Example 2 of Example 1 of the present invention. Figure 4 ;

[0041] Figure 14 Schematic diagram of the component top contact analysis results of Example 2 of Example 1 of the present invention Figure 1 ;

[0042] Figure 15 Schematic diagram of the component top contact analysis results of Example 2 of Example 1 of the present invention Figure 2 ;

[0043] Figure 16 Schematic diagram of the component top contact analysis results of Example 2 of Example 1 of the present invention Figure 3 ;

[0044] Figure 17 Schematic diagram of the component top contact analysis results of Example 2 of Example 1 of the present invention Figure 4 ;

[0045] Figure 18 It is a structural schematic diagram of a fast reactor full core assembly seismic analysis system in the second embodiment of the present invention. DETAILED DESCRIPTION

[0046] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0047] Example 1

[0048] A method for seismic analysis of the entire core assembly of a fast reactor, see Figure 1-Figure 2This method is used for seismic analysis and calculation of core assemblies for fast reactor cores. In the core system, the core assemblies are arranged in a regular hexagonal shape within the shroud. The bottoms of the core assemblies are inserted into spherical supports. The bottoms of all core assemblies are supported by the supports, while the tops of edge core assemblies may collide with the shroud. In this seismic system, the spherical supports and the shroud are both considered rigid bodies, and their deformation is ignored. Spacers are placed between the core assemblies, and the core assemblies are fixed by pins inserted into sockets. The spherical supports provide unilateral positional limits for the core assemblies. The method includes the following steps: S10 to S60.

[0049] S10: Based on numerical simulation, a gap-damper-spring connector is obtained to simulate the nonlinear collision of core components. The motion state of each core component and the contact state of each connector are initialized to obtain the nonlinear multi-component system of the entire reactor. The nonlinear multi-component system of the entire reactor is equivalently decomposed into a series of linear single-component vibration systems.

[0050] The motion state of each core component and the contact state of each connector are initialized to obtain the nonlinear multi-component system of the whole reactor. Specifically, the numerical simulation based on the software ABAQUS is performed. At time t = 0, the initial velocity and displacement of each degree of freedom of each core component are 0, and each connector is in a non-contact state. The dynamic motion equation of the nonlinear multi-component system of the whole reactor is expressed as:

[0051]

[0052] Where F(t) represents the external force on the core, which comes from seismic excitation; is the acceleration vector of the multi-component system, is the velocity vector of the multi-component system, U(t) is the displacement vector of the multi-component system, M represents the overall mass matrix of the system, C represents the damping matrix of the system, and K represents the stiffness matrix of the system.

[0053] In this system, the spring force of the connector is the internal force of the system. In order to solve the collision force, the entire dynamic equation needs to be solved. However, the large number of degrees of freedom of the system matrix will make the calculation time and the required memory too large, resulting in a huge computational burden. At the same time, due to the presence of nonlinear connectors within the system, this brings a large number of nonlinear calculation difficulties to the multi-component system. Therefore, directly solving the dynamic equations of the multi-component system is very uneconomical. In order to solve this difficulty, the present invention decomposes the multi-component system with significant nonlinearity and equates it to a series of linear single-component vibration systems. At this time, the spring force of the connector becomes the external force of a single component, and it changes with time.

[0054] The full-stack nonlinear multi-component system is equivalently decomposed into a series of linear single-component vibration systems, specifically including:

[0055] The full stack nonlinear multi-component system is decomposed through the connector. At a certain moment, the single-component vibration system is a linear single-component vibration system, and its dynamic motion equation is:

[0056]

[0057] Where f(t) represents the external force of the component, which comes from the spring force of the connector; represents the acceleration vector of a single component, represents the velocity vector of a single component, u(t) represents the displacement vector of a single component, m represents the overall mass matrix of the core component, c represents the damping matrix of the core component, and k represents the stiffness matrix of the core component. In the full-core nonlinear multi-component system, the seismic excitations received by the core components are converted into the spring forces of the connectors.

[0058] S20: Calculate the natural frequency and corresponding modal vibration shape of the selected characteristic component. Based on numerical simulation, calculate the additional mass coefficient of the characteristic component to simulate the influence of fluid-structure interaction on the vibration of the component.

[0059] After the above system decomposition, we get a series of vibration systems with similar components. In order to facilitate subsequent calculations, we need to select characteristic components and perform modal analysis to obtain the natural frequency and modal vibration shape of the components. During modal analysis, the free vibration equation of the system without considering the influence of damping is solved, that is,

[0060]

[0061] Assuming the solution is in the form: u(t) = φsinω(t-t0), we get a generalized eigenvalue problem, namely:

[0062] kυ-ω 2 mφ=0

[0063] Among them, φ is the nth order vector, ω is the vibration frequency of vector φ, t is the time variable, and t0 is the time constant determined by the initial conditions. According to the characteristic analysis, n characteristic solutions can be obtained, namely According to the orthogonality and regularity of the natural vibration modes, we can get:

[0064]

[0065] That is: Φ T mΦ=I,Φ T kΦ=Ω, Φ and Ω represent the natural vibration mode matrix and the natural frequency matrix respectively.

[0066] Among them, the additional mass coefficient of the characteristic component is calculated to simulate the influence of fluid-solid coupling on the vibration of the component. Specifically, the additional mass coefficient of the characteristic component is calculated based on the numerical simulation of the software ABAQUS to approximately simulate the influence of fluid-solid coupling on the vibration of the component.

[0067] Because fast reactor core assemblies are immersed in coolant, the gap between the two assemblies is very small. When an earthquake occurs, the coolant significantly affects the movement and deformation of the core assembly structure, causing the structural vibration to exhibit strong nonlinearity. Therefore, the fluid-structure coupling effect is crucial for the seismic analysis of fast reactor cores. To quantify the influence of fluid on structural motion, traditional potential flow theory relies heavily on component shape and is unsuitable for the development of seismic analysis programs for large-scale component groups. The present invention combines a full-scale acoustic-structure coupling model in the finite element software ABAQUS to determine the added mass coefficient of the beam unit model, comprising steps S21 to S24.

[0068] S21: Based on the Euler-Bernoulli beam theory, the real core components are simplified into a beam unit model, and the typical characteristic beam model boundary conditions are selected: the bottom edge is fixed and the upper end is free.

[0069] S22: The concentrated additional mass is evenly distributed along the axial direction of the core assembly to equivalently simulate the influence of the fluid on the assembly vibration.

[0070] S23: In the Abaqus numerical simulation, the first-order natural frequency of the core assembly is adjusted by changing the added mass coefficient of the cross section of the beam element model so that the natural frequency of the core assembly is equal to the wet frequency of the assembly in the coolant.

[0071] S24: The damping effect of the fluid on the core assembly is equivalently simulated by an additional damping coefficient, which is determined by the vibration test results.

[0072] S30: Based on the Euler-Bernoulli theory, an equivalent beam model of the core assembly is constructed. Combined with the connector and the additional mass coefficient, a finite beam unit model of a single core assembly that is independent of each other is established. The connectors are respectively set between the core assembly and the core assembly pad, between the core assembly and the spherical support, and between the pins and the sockets.

[0073] Among them, based on the Euler-Bernoulli theory, an equivalent beam model of the core assembly is constructed, and a finite beam unit model of a single core assembly that is independent of each other is established by combining the gap-damping-spring connector and the additional mass coefficient, which specifically includes steps: S31 to S36.

[0074] S31: Based on the Euler-Bernoulli beam theory, under the 2D plane assumption, the finite element equations of the general plane beam element are derived. In the local coordinate system, each node of the general plane beam element has three degrees of freedom, namely the deflection in the Y direction, the axial displacement in the X direction, and the rotation angle in the plane.

[0075] Each beam element has 6 degrees of freedom. Among them, the deformation and stress states of the straight beam element in the beam element are not coupled with each other, and the axial stiffness is directly superimposed, which is equivalent to the simple superposition of the axial force rod element and the beam element, that is, the superposition of the stiffness matrices of the two.

[0076] Beam element node displacement q e , beam element node force P e Expressed as:

[0077]

[0078] Wherein, u1, ν1 and θ1 represent the plane displacement and rotation angle of the first node in the beam element, u2, ν2 and θ2 represent the plane displacement and rotation angle of the second node in the beam element; P u1 、P ν1 and M1 represent the nodal force and bending moment at the first node in the beam element, P u2 、P ν2 and M2 represent the nodal force and bending moment at the second node in the beam element.

[0079] The element stiffness matrix K of the beam element e and the mass matrix M of the beam element e Expressed as:

[0080]

[0081]

[0082] Wherein, E represents the Young's modulus of the material in the beam element, ρ represents the material density of the material in the beam element, A represents the cross-sectional area of the material in the beam element, l represents the unit length of the material in the beam element, and I represents the moment of inertia of the material in the beam element; ∈ is taken as 0.0001.

[0083] S32: The gap-damping-spring connector is arranged between the core assembly and the core assembly pad, between the core assembly and the spherical support, between the pin and the socket, and between the connectors between the core assembly and the shroud, wherein the core assembly is arranged in a regular hexagon in the shroud, and the top of the core assembly at the edge will collide with the shroud.

[0084] In the attached Figure 5 In the figure, a is a schematic diagram of the collision position, b is a schematic diagram of the connector and nonlinear spring stiffness, and c is a schematic diagram of the analysis of the collision force on the upper boss and pin of the component. Due to the compact arrangement characteristics of the hexagonal components in the fast reactor core, such as Figure 5As shown in the figure, under earthquake conditions, nonlinear collisions can occur between the spacers on the upper and middle bosses of the core assembly, between the spherical supports and the assembly, and between the pins and sockets. Therefore, simulating the gaps and collision forces between the spacers and the pin sockets is crucial. Furthermore, the spherical supports act as a single-sided limiter for the assembly. To perform nonlinear component collision analysis, the analysis process is as follows:

[0085] Gap-damping-spring connectors are set between the core assembly and the core assembly spacer, between the core assembly and the spherical support, and between the pin and the socket to simulate the real gap. The collision force at these locations is approximately calculated by the deformation of the spring. δ and k represent the gap value and collision stiffness of the connector, respectively.

[0086] S33: The collision stiffness of the equivalent gap-damper-spring connector and the damping coefficient of the gap-damper-spring connector are measured through collision tests; the gap value of the gap-damper-spring connector is determined by the gap between the core assemblies and the gap between the core assembly and the shroud.

[0087] S34: In the vertical direction, since the ball seat support plays a unilateral limiting role on the core assembly, a unilateral equivalent spring needs to be set at the spherical seat position to simulate the vertical collision.

[0088] S35: The connectors between the core assembly and the core assembly spacer and the connector between the core assembly and the shroud are single-sided connectors, while the connectors between the core assembly and the spherical support and the connectors between the pins and the sockets are double-sided connectors.

[0089] The connectors between the core assembly and the core assembly pads and the connectors between the core assembly and the shroud are unilateral connectors, that is, only the compression state of the spring is considered, and the spring force in the extension state is not considered; the connectors between the core assembly and the spherical support and the connectors between the pins and the sockets are bilateral connectors, that is, the compression and extension states of the spring are considered, with extension being positive and compression being negative.

[0090] S36: Calculation of core assembly collision force: The top collision force of the core assembly is represented by the collision force between the core assemblies in six directions around the core assembly. The collision force between the core assembly and the spherical support and between the pin and the support are directly calculated by the double-sided connector in the XY direction. Figure 5 As shown in the figure, taking the force analysis of the top of component 3 as an example, the collision forces of the six components in the six directions are synthesized into collision forces in the X / Y directions and applied to the finite element analysis model; the collision forces in the X / Y horizontal directions at the pin position of component 3 can be directly calculated by the bilateral connector. Based on the above Euler Bernoulli theory, collision model and fluid-structure coupling additional mass, a simplified beam unit model of the full core component is established, as shown in Figure 6 shown.

[0091] S40: Reduce the dimension of a single core assembly vibration system to a single degree of freedom system.

[0092] Specifically, based on the natural frequencies and corresponding modal vibration shapes of the characteristic components of S10, the modal superposition method is used to solve the dynamic response of the system, and the dynamic response of the system in physical coordinates is converted into the dynamic response in modal coordinates to achieve dimensionality reduction.

[0093] In a specific example, the modal superposition method is further improved to approximate the dynamic response of the structure under gap conditions, reducing the dimension of the single-component vibration system to a single-degree-of-freedom system, thereby improving computational efficiency. Based on the component natural frequency and natural vibration mode obtained in step 1, the modal superposition method is used to solve the dynamic response of the system, converting the dynamic response of the system in physical coordinates into the dynamic response in modal coordinates:

[0094]

[0095] Where, q(t)=[q1(t) q2(t) q3(t) … q n (t)] T The meaning of the above transformation is to regard u(t) as φ i The linear combination of i It can be regarded as a generalized displacement basis vector, q i Is a generalized displacement value. Mathematically, it is the transformation of the displacement vector u(t) from the n-dimensional space of the finite element system's node displacement as the basis vector (also known as the physical coordinate) to the n-dimensional space of φ i is the n-dimensional space of basis vectors (also known as mode coordinates or modal coordinates). At the same time, the linear superposition of a small number of mode shapes is used to approximate the dynamic response in physical coordinates to achieve dimensionality reduction.

[0096] Substitute the above transformation into the equation of motion and multiply both ends by Φ T , we can get the equation of motion in the new basis vector space:

[0097]

[0098] The above formula can be converted into m mutually uncoupled single-degree-of-freedom second-order ordinary differential equations:

[0099]

[0100] Due to the nonlinear boundary conditions of large-scale core components such as gaps and collisions, the deformation of fast reactor core components mainly includes the linear superposition of component rigid body translation and modal vibration shapes. Therefore, in order to make the modal superposition method suitable for approximate simulation of component deformation with rigid body translation components, such as Figure 7As shown, the dynamic response of the present invention in modal coordinates is The rigid body translation components are added: φ1, φ2, and φ3 represent the vertical, horizontal, and rotational translations of the component, respectively, while φ4, φ5, and φ6 represent the first three modal shapes of the cantilever beam. It is worth noting that the rigid body translation components φ1–φ3 also require mass matrix regularization to maintain uniform numerical dimensions.

[0101] S50: The central difference method is used to calculate the vibration response of the single-degree-of-freedom system in modal coordinates, and the vibration response is converted into the dynamic response in physical coordinates.

[0102] Among them, the central difference method is used to calculate the vibration response of the single-degree-of-freedom system in modal coordinates, and the vibration response is converted into the dynamic response in physical coordinates, including:

[0103] The acceleration and speed Use displacement q i (t) means:

[0104]

[0105]

[0106] In order to solve the displacement q at time t+Δt i (t+Δt), bringing the above velocity and acceleration into the motion equation of the multi-degree-of-freedom system, we can get the recursive formula of the central difference method, which is:

[0107]

[0108] When t=0, we can get q i (-Δt), that is

[0109]

[0110] where q i (0) and can be obtained from the given initial conditions, and Then we can use the equation of motion at t=0 to get:

[0111]

[0112] At this point, the algorithm steps for solving the motion equations using the central difference method can be summarized as follows:

[0113] 1) Initial calculation

[0114] · Forming stiffness Mass 1 and damping 2ω i ξ i ;

[0115] Given q i (0), and

[0116] Choose a time step Δt, where Δt < Δt cr , and calculate the integration constant c2 = 2c0 and c3 = 1 / c2;

[0117] ·calculate

[0118] Forming effective quality

[0119] Triangular decomposition

[0120] 2) For each time step (t=0,Δt,2Δt,…)

[0121] Calculate the payload at time t

[0122]

[0123] Solve for the displacement at time t+Δt

[0124]

[0125] S60: Determine whether the earthquake acceleration time history stops. If the earthquake acceleration time history stops, perform deflection analysis and contact analysis. If the earthquake acceleration time history does not stop, repeat S30 to S50.

[0126] Among them, performing deflection analysis and contact analysis specifically includes: obtaining the maximum deflection distribution diagram and fitting curve of the component top under different component gap conditions and the maximum collision force distribution diagram and fitting curve of the component top under different component gap conditions.

[0127] Two examples are given below to further illustrate the present invention. Figure 7 The acceleration time history of the earthquake (Northridge earthquake record) is displayed. Steel is selected as an example of the material, with a Poisson's ratio of 0.3, a Young's modulus of E=210GPa, and a material density of 7800kg / m^3.

[0128] (1) Example 1: This example uses a seven-component structural model to demonstrate the effectiveness of a proposed efficient seismic analysis method for fast reactor core components. Figure 9The calculation results of the seismic analysis method proposed in this invention and the finite element software ABAQUS are compared, where a shows the comparison of the motion trajectory of the component top, and b shows the time history diagram of the impact force at the component top, as shown in Figure 1. Figure 9 As shown in part a of FIG, the motion trajectory of the component top calculated by the method proposed in the present invention and the ABAQUS software is very similar, and the error of the motion range in the X / Y direction is very small; Figure 9 As shown in part b of the figure, the time history of the impact force on the top of the component obtained by the two methods is compared. Obviously, the distribution of the impact force is very similar, with the maximum impact force being 3493.04N and 3305.99N, respectively, with an error of only 6.37%. However, in terms of computational efficiency, the calculation time of the method proposed in this invention is 100.49s, while the calculation time of ABAQUS software under parallel computing conditions is close to 30h, which improves the computational efficiency by 3 orders of magnitude. Therefore, this example verifies that the seismic analysis method proposed in this invention can efficiently calculate the seismic response of the core component.

[0129] Example 2: This example further analyzes the effect of model parameters (number of component layers and component gaps) on the deformation and contact of the full core component. In the deflection analysis, Figure 10-13 The distribution diagram and fitting curve of the maximum deflection of the component top under different component layer numbers are shown. As the number of component layers increases, the maximum and minimum deflections of the components in the core and the maximum deflection of the central component all increase. This is mainly because the large scale of the components makes the core have a greater inertia effect, resulting in an increase in the deformation level of the top; at the same time, the deformation degree at the center of the core is significantly smaller than that of the edge components. Figure 10-13 As shown, Figure 10 is the maximum deflection distribution diagram of the component top under different component layer numbers (number of core components), Figure 11 is the fitting curve of the maximum deflection of the component top under different component layer numbers (number of core components), Figure 12 Represents the maximum deflection distribution of the component top under different gap conditions, Figure 13 Fitted curves representing the maximum deflection of the component top under different gap conditions. Figure 10 The maximum deflection distribution and fitting curves at the top of the core components under different component gap conditions are shown. Clearly, as the component gap increases, the deformation level at the top of the core components increases linearly. When the gap is less than 2 mm, the deformation level inside the core is lower than that of the edge components. However, when the gap is too large, the deflection level at the top of the edge components drops significantly, resulting in extensive localized deformation.

[0130] In contact analysis, Figure 13-14 The middle is a histogram of the maximum collision force at the top of each component layer and a distribution diagram of the maximum collision force of the component under different component layer numbers (number of core components). Figure 16-17Respectively represent the maximum collision force distribution diagram and fitting curve of the component top under different gap conditions. Figure 13-14 The figure shows the distribution diagram and histogram of the maximum impact force at the top of the module under different module layer numbers. When the number of module layers remains unchanged, the closer the module is positioned within the core, the smaller the maximum impact force. This phenomenon is mainly due to the fact that the outer modules have more room to move and have greater energy. When the module position remains unchanged, the maximum impact force at this location increases with the number of module layers (module size), mainly due to the greater inertia of the core. Figure 16-17 The maximum impact force distribution and fitting curves for the component tips under different component gap conditions are shown in Figure 2. Clearly, the impact strength at the core component tips increases linearly with increasing component gaps; the impact force level within the core is lower than that at the edge components.

[0131] Example 2

[0132] A fast reactor full core assembly seismic analysis system is used for seismic analysis and calculation of fast reactor core assemblies in the time history of earthquake acceleration. Spacers are set between the core assemblies, and the core assemblies are fixed by inserting pins into sockets. The spherical supports limit the core assemblies on one side. Figure 18 As shown, it includes a single-component vibration system generation module 71, an additional mass coefficient calculation module 72, an equivalent beam model construction module 73, a dimension reduction module 74, a physical response module 75 and a time judgment module 76.

[0133] A single-component vibration system generation module 71 is used to obtain, based on numerical simulation, a gap-damper-spring connector for simulating nonlinear collisions of core components, initialize the motion state of each core component and the contact state of each connector, obtain a full-core nonlinear multi-component system, and decompose the full-core nonlinear multi-component system into a series of linear single-component vibration systems.

[0134] An additional mass coefficient calculation module 72 is used to calculate the natural frequency and corresponding mode shape of the selected characteristic component, and calculate the additional mass coefficient of the characteristic component based on numerical simulation to simulate the influence of fluid-structure interaction on the vibration of the component;

[0135] An equivalent beam model construction module 73 is used to construct an equivalent beam model of the core assembly based on the Euler-Bernoulli theory, and to establish a finite beam unit model of a single core assembly that is independent of each other by combining connectors and additional mass coefficients, wherein connectors are provided between the core assembly and the core assembly spacer, between the core assembly and the spherical support, and between the pin and the socket.

[0136] Dimensionality reduction module 74, used to reduce the dimension of a single core assembly vibration system to a single degree of freedom system solution;

[0137] A physical response module 75 is used to calculate the vibration response of the single-degree-of-freedom system in modal coordinates using a central difference method, and convert the vibration response into a dynamic response in physical coordinates;

[0138] The time judgment module 76 is used to judge whether the earthquake acceleration time history has stopped. If the earthquake acceleration time history has stopped, deflection analysis and contact analysis are performed.

[0139] In this embodiment, the time judgment module 76 is also used to determine whether the earthquake acceleration time history has stopped. If the earthquake acceleration time history has not stopped, the equivalent beam model construction module 73, the dimensionality reduction module 74 and the physical response module 75 are repeatedly executed in sequence.

[0140] In some embodiments, the motion state of each core assembly and the contact state of each connector are initialized.

[0141] The full-stack nonlinear multi-component system is obtained, including:

[0142] Based on the numerical simulation software ABAQUS, at time t = 0, the initial velocity and displacement of each degree of freedom of each core component are 0, and each connector is in a non-contact state. The dynamic motion equation of the full-core nonlinear multi-component system is expressed as:

[0143]

[0144] Where F(t) represents the external force on the core, which comes from seismic excitation; is the acceleration vector of the multi-component system, is the velocity vector of the multi-component system, U(t) is the displacement vector of the multi-component system, M represents the overall mass matrix of the system, C represents the damping matrix of the system, and K represents the stiffness matrix of the system;

[0145] The full stack nonlinear multi-component system is equivalently decomposed into a series of linear single-component vibration systems, including:

[0146] The full stack nonlinear multi-component system is decomposed through the connector. At a certain moment, the single-component vibration system is a linear single-component vibration system, and its dynamic motion equation is:

[0147]

[0148] Where f(t) represents the external force of the component, which comes from the spring force of the connector; represents the acceleration vector of a single component, represents the velocity vector of a single component, u(t) represents the displacement vector of a single component, m represents the overall mass matrix of the core component, c represents the damping matrix of the core component, and k represents the stiffness matrix of the core component. In the full-core nonlinear multi-component system, the seismic excitations received by the core components are converted into the spring forces of the connectors.

[0149] In some embodiments, the added mass coefficient of the characteristic component is calculated to simulate the effect of fluid-structure interaction on the vibration of the component. Specifically, the added mass coefficient of the beam element model is determined by combining the full-scale acoustic-structure interaction model of the finite element software ABAQUS. The steps are as follows:

[0150] Based on the Euler-Bernoulli beam theory, the real core assembly is simplified into a beam unit model, and the typical characteristic beam model boundary conditions are selected: the bottom edge is fixed and the upper end is free;

[0151] The concentrated additional mass is evenly distributed along the axial direction of the core assembly to equivalently simulate the effect of fluid on the assembly vibration;

[0152] In the Abaqus numerical simulation, the first-order natural frequency of the core assembly is adjusted by changing the added mass coefficient of the cross section of the beam element model so that the natural frequency of the core assembly is equal to the wet frequency of the assembly in the coolant.

[0153] The damping effect of the fluid on the core assembly is equivalently simulated by an additional damping coefficient, which is determined by the vibration test results.

[0154] In some embodiments, based on the Euler-Bernoulli theory, an equivalent beam model of the core assembly is constructed, and a finite beam element model of a single core assembly that is independent of each other is established by combining a gap-damper-spring connector and an additional mass coefficient. Specifically, the model includes:

[0155] Based on the Euler-Bernoulli beam theory, the finite element equations of the general plane beam element are derived under the 2D plane assumption. In the local coordinate system, each node of the general plane beam element has three degrees of freedom, namely, the deflection in the Y direction, the axial displacement in the X direction, and the rotation angle in the plane.

[0156] Each beam element has 6 degrees of freedom, among which the deformation and stress states of the straight beam element in tension, compression and bending are not coupled with each other, and the axial stiffness is directly superimposed;

[0157] Beam element node displacement q e , beam element node force P e Expressed as:

[0158]

[0159] Where u1 and ν1 represent the plane displacement of the first node in the beam element, θ1 represents the rotation angle of the first node in the beam element, u2 and ν2 represent the plane displacement of the second node in the beam element, and θ2 represents the rotation angle of the second node in the beam element;

[0160] P u1 and P ν1 represents the nodal force at the first node in the beam element, M1 represents the bending moment at the first node in the beam element, and P u2 and P ν2 M2 represents the bending moment at the second node in the beam element.

[0161] The element stiffness matrix K of the beam element e and the mass matrix M of the beam element e Expressed as:

[0162]

[0163]

[0164] Wherein, E represents the Young's modulus of the material in the beam element, ρ represents the material density of the material in the beam element, A represents the cross-sectional area of the material in the beam element, l represents the unit length of the material in the beam element, and I represents the moment of inertia of the material in the beam element; ∈ is taken as 0.0001;

[0165] Gap-damping-spring connectors are provided between the core assembly and the core assembly pad, between the core assembly and the spherical support, between the pin and the socket, and between the core assembly and the shroud, wherein the core assembly is arranged in a regular hexagon in the shroud, and the top of the core assembly at the edge will collide with the shroud.

[0166] The collision stiffness of the equivalent gap-damping-spring connector and the damping coefficient of the gap-damping-spring connector are measured through collision tests; the gap value of the gap-damping-spring connector is determined by the gap between the core assemblies and the gap between the core assembly and the spherical support;

[0167] In the vertical direction, since the ball seat supports act as a unilateral limit for the core assembly, a unilateral equivalent spring needs to be set at the spherical seat position to simulate vertical collisions.

[0168] The connectors between the core assembly and the core assembly spacer, as well as the connectors between the core assembly and the shroud, are single-sided connectors, while the connectors between the core assembly and the spherical support, and between the pins and the sockets are double-sided connectors.

[0169] Calculation of core assembly collision force: The collision force at the top of the core assembly is represented by the resultant collision force between the core assemblies in six directions around the core assembly. The collision forces between the core assembly and the spherical support and between the pin and the support are both directly calculated by the bilateral connectors in the XY directions.

[0170] In some embodiments, reducing the dimension of a single-component vibration system to a single-degree-of-freedom system includes:

[0171] Based on the natural frequencies and corresponding modal vibration shapes of the characteristic components in step one, the modal superposition method is used to solve the dynamic response of the system, and the dynamic response of the system in physical coordinates is converted into the dynamic response in modal coordinates to achieve dimensionality reduction.

[0172] In some embodiments, deflection analysis and contact analysis are performed, specifically including: obtaining a maximum deflection distribution diagram and fitting curve of the component top under different component gap conditions and a maximum collision force distribution diagram and fitting curve of the component top under different component gap conditions.

[0173] In some embodiments, a central difference method is used to calculate the vibration response of a single-degree-of-freedom system in modal coordinates, and the vibration response is converted into a dynamic response in physical coordinates, including:

[0174] The acceleration and speed Use displacement q i (t) means:

[0175]

[0176]

[0177] The above acceleration and speed Substituting the motion equation of the multi-degree-of-freedom system into the equation, we can obtain the recursive formula of the central difference method, which is:

[0178]

[0179] When t=0, we can get q i (t-Δt), Δt is the time step:

[0180]

[0181] Among them, the initial displacement q i (t0) and initial velocity can be obtained from the given initial conditions, and Then we can use the equation of motion at t=0 to get:

[0182]

[0183] The central difference method is used to gradually solve the motion equation at t = 0, and the stiffness is obtained as The mass is unit mass and the damping is 2ω i ξ i ;

[0184] Where Δt<Δt cr , and calculate the integration constant c2=2c0 and c3=1 / c2, forming the effective mass

[0185] Calculate the effective load at each time t of the earthquake acceleration time history where t=0,Δt,2Δt,…

[0186]

[0187] Based on the effective mass and effective load, solve for the displacement q at time t+Δt i (t+Δt):

[0188] The implementation process, method and effect of the seismic analysis system for a fast reactor full core assembly in this embodiment are the same as those of the seismic analysis method for a fast reactor full core assembly described in the first embodiment, and will not be described in detail here.

[0189] Example 3

[0190] The present invention relates to a computer-readable storage medium, which stores instructions. When the instructions are executed, a method for seismic analysis of a full core assembly of a fast reactor is executed. The implementation process, method and effect of the method are the same as those of the method for seismic analysis of a full core assembly of a fast reactor described in Example 1, and will not be repeated here.

[0191] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0192] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for seismic analysis of a fast reactor core assembly, characterized in that: Used for seismic analysis and calculation of core assemblies of a fast reactor core during earthquake acceleration time history, wherein spacers are provided between the core assemblies, the core assemblies are fixed by inserting pins into sockets, and spherical supports provide unilateral positional limitation for the core assemblies, including: Step 1: Based on numerical simulation, a gap-damper-spring connector for simulating nonlinear collision of core components is obtained. The motion state of each core component and the contact state of each connector are initialized to obtain a full-core nonlinear multi-component system. The full-core nonlinear multi-component system is equivalently decomposed into a series of linear single-component vibration systems. Step 2: Calculate the natural frequency and corresponding mode shape of the selected characteristic component, and calculate the added mass coefficient of the characteristic component based on numerical simulation to simulate the effect of fluid-structure interaction on the component vibration; Step 3: Based on the Euler-Bernoulli theory, an equivalent beam model of the core assembly is constructed. In combination with the connector and the additional mass coefficient, a finite beam unit model of a single core assembly that is independent of each other is established. The connector is respectively provided between the core assembly and the core assembly spacer, between the core assembly and the spherical support, and between the pin and the socket. Step 4: Reduce the dimension of the single-component vibration system to a single-degree-of-freedom system; Step 5: Calculate the vibration response of the single-degree-of-freedom system in modal coordinates using the central difference method, and convert the vibration response into a dynamic response in physical coordinates; Step 6: Determine whether the earthquake acceleration time history stops. If the earthquake acceleration time history stops, perform deflection analysis and contact analysis.

2. The method for seismic analysis of a fast reactor core assembly according to claim 1, characterized in that: The step of determining whether the earthquake acceleration time history has stopped further includes, if the earthquake acceleration time history has not stopped, repeating steps three to five in sequence.

3. The method for seismic analysis of a fast reactor core assembly according to claim 1, characterized in that: Initializing the motion state of each core component and the contact state of each connector to obtain a full-core nonlinear multi-component system specifically includes: Based on the numerical simulation of the software ABAQUS, at time t=0, the initial velocity and displacement of each degree of freedom of each core component are 0, and each connector is in a non-contact state. The dynamic motion equation of the full-core nonlinear multi-component system is expressed as: Where F(t) represents the external force on the core, which comes from seismic excitation; is the acceleration vector of the multi-component system, is the velocity vector of the multi-component system, U(t) is the displacement vector of the multi-component system, M represents the overall mass matrix of the system, C represents the damping matrix of the system, and K represents the stiffness matrix of the system; The equivalent decomposition of the full stack nonlinear multi-component system into a series of linear single-component vibration systems specifically includes: The full stack nonlinear multi-component system is decomposed through the connector. At a certain moment, the single-component vibration system is a linear single-component vibration system, and its dynamic motion equation is: Where f(t) represents the external force of the component, which comes from the spring force of the connector; represents the acceleration vector of a single component, represents the velocity vector of a single component, u(t) represents the displacement vector of a single component, m represents the overall mass matrix of the core component, c represents the damping matrix of the core component, and k represents the stiffness matrix of the core component, wherein the seismic excitations received by the core component in the full-stack nonlinear multi-component system are all converted into the spring force of the connector.

4. The method for seismic analysis of a fast reactor core assembly according to claim 1, wherein: The added mass coefficient of the characteristic component is calculated to simulate the influence of fluid-structure coupling on the vibration of the component. Specifically, the added mass coefficient of the beam unit model is determined by combining the full-scale acoustic-structure coupling model of the finite element software ABAQUS. The steps are as follows: Based on the Euler-Bernoulli beam theory, the actual core assembly is simplified into a beam unit model, and the typical characteristic beam model boundary conditions are selected: the bottom edge is fixed and the upper end is free; uniformly distributing concentrated additional mass along the axial direction of the core assembly to equivalently simulate the influence of fluid on assembly vibration; In an Abaqus numerical simulation, adjusting the first-order natural frequency of the core assembly by changing the added mass coefficient of the cross section of the beam element model so that the natural frequency of the core assembly is equal to the wet frequency of the assembly in the coolant; The damping effect of the fluid on the core assembly is equivalently simulated by an additional damping coefficient, and the additional damping coefficient is determined by vibration test results.

5. The method for seismic analysis of a fast reactor core assembly according to claim 1, characterized in that: The equivalent beam model of the core assembly is constructed based on the Euler-Bernoulli theory, and a finite beam element model of a single core assembly that is independent of each other is established by combining the gap-damper-spring connector and the additional mass coefficient. Specifically, the model includes: Based on the Euler-Bernoulli beam theory, the finite element equation of the general plane beam element is derived under the 2D plane assumption. In the local coordinate system, each node of the general plane beam element has three degrees of freedom, namely, the deflection in the Y direction, the axial displacement in the X direction, and the rotation angle in the plane. Each beam element has 6 degrees of freedom, among which the deformation and stress states of the straight beam element in tension, compression and bending are not coupled with each other, and the axial stiffness is directly superimposed; The beam element node displacement q e , the beam unit node force P e Expressed as: Wherein, u1 and ν1 represent the plane displacement of the first node in the beam element, θ1 represents the rotation angle of the first node in the beam element, u2 and ν2 represent the plane displacement of the second node in the beam element, and θ2 represents the rotation angle of the second node in the beam element; P u1 and P ν1 represents the nodal force of the first node in the beam element, M1 represents the bending moment of the first node in the beam element, and P u2 and P ν2 represents the nodal force of the second node in the beam element, and M2 represents the bending moment of the second node in the beam element; The element stiffness matrix K of the beam element e and the mass matrix M of the beam element e Expressed as: Wherein, E represents the Young's modulus of the material in the beam element, ρ represents the material density of the material in the beam element, A represents the cross-sectional area of the material in the beam element, l represents the unit length of the material in the beam element, and I represents the moment of inertia of the material in the beam element; ∈ is taken as 0.0001; The gap-damping-spring connector is provided between the core assembly and the core assembly spacer, between the core assembly and the spherical support, between the pin and the socket, and between the connectors between the core assembly and the shroud, wherein the core assembly is arranged in a regular hexagon in the shroud, and the top of the core assembly at the edge will collide with the shroud; The collision stiffness of the equivalent gap-damping-spring connector and the damping coefficient of the gap-damping-spring connector are measured through a collision test; the gap value of the gap-damping-spring connector is determined by the gap between the core assemblies and the gap between the core assembly and the shroud; In the vertical direction, since the ball seat supports act as a unilateral limit for the core assembly, a unilateral equivalent spring needs to be set at the spherical seat position to simulate vertical collisions. The connectors between the core assembly and the core assembly spacer, as well as the connectors between the core assembly and the shroud, are single-sided connectors, while the connectors between the core assembly and the spherical support, and between the pins and the sockets are double-sided connectors. Calculation of core assembly collision force: The collision force at the top of the core assembly is represented by the resultant collision force between the core assemblies in six directions around the core assembly. The collision forces between the core assembly and the spherical support and between the pin and the support are both directly calculated by the bilateral connectors in the XY directions.

6. A fast reactor full core assembly seismic analysis method according to claim 1, characterized in that : The solution of reducing the dimension of the single-component vibration system to a single-degree-of-freedom system includes: Based on the natural frequency and corresponding modal vibration shape of the characteristic component in step one, the modal superposition method is used to solve the dynamic response of the system, and the dynamic response of the system in physical coordinates is converted into the dynamic response in modal coordinates to achieve dimensionality reduction.

7. The method for seismic analysis of a fast reactor core assembly according to claim 1, characterized in that: The performing of the deflection analysis and the contact analysis specifically includes obtaining a maximum deflection distribution diagram and a fitting curve of the component top under different component gap conditions, and a maximum collision force distribution diagram and a fitting curve of the component top under different component gap conditions.

8. A fast reactor full core assembly seismic analysis system, characterized in that: Used for seismic analysis and calculation of core assemblies of a fast reactor core during earthquake acceleration time history, wherein spacers are provided between the core assemblies, the core assemblies are fixed by inserting pins into sockets, and spherical supports provide unilateral positional limitation for the core assemblies, including: a single-component vibration system generation module, configured to obtain, based on numerical simulation, a gap-damper-spring connector for simulating nonlinear collisions of core components, initialize the motion state of each core component and the contact state of each connector, obtain a full-core nonlinear multi-component system, and decompose the full-core nonlinear multi-component system into a series of linear single-component vibration systems; An additional mass coefficient calculation module is used to calculate the natural frequency and corresponding mode shape of the selected characteristic component, and based on numerical simulation, calculate the additional mass coefficient of the characteristic component to simulate the influence of fluid-structure interaction on the vibration of the component; an equivalent beam model construction module, configured to construct an equivalent beam model of the core assembly based on the Euler-Bernoulli theory, and to establish an independent finite beam unit model of a single core assembly in combination with the connector and the additional mass coefficient, wherein the connector is respectively provided between the core assembly and the core assembly spacer, between the core assembly and the spherical support, and between the pin and the socket; A dimensionality reduction module, for reducing the dimension of the single-component vibration system to a solution of a single-degree-of-freedom system; A physical response module, configured to calculate the vibration response of the single-degree-of-freedom system in modal coordinates using a central difference method, and convert the vibration response into a dynamic response in physical coordinates; The time judgment module is used to judge whether the earthquake acceleration time history has stopped, and if the earthquake acceleration time history has stopped, perform deflection analysis and contact analysis.

9. A computer-readable storage medium, characterized in that: The storage medium stores instructions, which, when executed, execute a fast reactor full core assembly seismic analysis method according to any one of claims 1 to 7.

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