Reactor core hanging basket pre-tightening state degradation prediction method and device and medium

Abstract

The invention discloses a reactor core basket pre-tightening state degradation prediction method and device and a medium, and the method comprises the steps: building a statics model of a core basket structure and a core basket modal analysis model for a nuclear power plant core basket based on statics analysis and prestress modal analysis technologies; based on a reactor core hanging basket modal analysis model, obtaining a mapping relation between a reactor core hanging basket pre-tightening state degradation state and a reactor core hanging basket structure vibration response characteristic; constructing a reactor core hanging basket vibration characteristic trend prediction model according to the historical reactor core hanging basket vibration characteristic change data, and obtaining the prediction trend of the reactor core hanging basket vibration characteristics; and obtaining a prediction trend of the pre-tightening degradation state of the reactor core hanging basket according to the historical vibration characteristic change data of the reactor core hanging basket and the prediction trend of the vibration characteristics of the reactor core hanging basket in combination with the mapping relation. According to the method, the accurate change rule of the pre-tightening degradation state of the reactor core hanging basket can be predicted, and a foundation is laid for construction of a subsequent nuclear power key equipment health management system.

Description

Technical Field

[0001] The invention relates to the technical field of core hanging basket pre-tightening state degradation analysis, and in particular to a method, device and medium for predicting the pre-tightening state degradation of a reactor core hanging basket. Background Art

[0002] The core basket is the direct bearing structure of the core, the energy source of the nuclear power plant, and is a key device to protect the normal and stable operation of the core. Inside the pressure vessel, pressurized water, as the core coolant, will enter the pressure vessel through the nozzle on the wall of the pressure vessel and flow through the outer wall of the core basket. It will flow into the core basket from the coolant hole at the bottom of the core basket to cool the core, and finally flow out of the core basket from the nozzle on the wall of the core basket. Therefore, the core basket will vibrate under the turbulent excitation of the coolant, and the natural vibration frequency value of the core basket can be obtained by statistical signal processing of the neutron noise signal outside the core. During the operation of the reactor, the heat and radiation generated by the core will affect the microstructure of the materials of each metal component, resulting in changes in its mechanical properties. In particular, the components for structural pre-tightening of the core basket are in a state of compression deformation for a long time, and are prone to mechanical degradation in the harsh environment of the core, further affecting the motion characteristics of the core basket.

[0003] In the prior art, the analysis of the degradation state of the core basket preload is generally carried out by discretely modeling the compression spring in the form of multi-node displacement constraints. The degradation of the core basket preload state is simulated by reducing the number of constraint nodes, and the mechanism of the coolant's action on the core basket structure is simplified by adding mass. The influence of the spring at the top of the fuel assembly on the core basket structure is not considered.

[0004] However, the existing methods have the following problems: they ignore the structural characteristics of the compression spring itself and the friction contact force between the structures, the simulation method of the pre-tightening state of the core basket is too simplified, the buoyancy effect of the fluid flow on the core basket is not considered, and the hardening effect of the spring pre-tightening force on the top of the fuel assembly on the structural stiffness is ignored. Therefore, the current method does not effectively simulate the boundary constraints of the core basket, and cannot obtain the accurate change law of the pre-tightening degradation state of the core basket.

[0005] In view of this, this application is hereby filed. Summary of the invention

[0006] The technical problem to be solved by the present invention is that the core hanging basket pre-tightening degradation state analysis method in the prior art cannot predict the accurate change law of the core hanging basket pre-tightening degradation state. The purpose of the present invention is to provide a method, device and medium for predicting the degradation of the pre-tightening state of the reactor core hanging basket. First, based on static analysis and prestressed modal analysis technology, a static model of the core hanging basket structure and a modal analysis model of the core hanging basket under the action of pre-tightening force and coolant are established. Based on the modal analysis model of the core hanging basket, a mapping relationship between the degradation degree of the pre-tightening state of the nuclear power plant reactor core hanging basket and the vibration response characteristics of the core hanging basket structure is obtained, so as to realize the analysis and judgment of the degradation degree of the pre-tightening state of the reactor core hanging basket; second, based on the historical core hanging basket vibration characteristic change data, a core hanging basket vibration characteristic trend prediction model is constructed to obtain the trend prediction of the core hanging basket vibration characteristics; based on the trend prediction of the core hanging basket vibration characteristics, combined with the mapping relationship between the degradation degree of the core hanging basket pre-tightening state and the vibration response characteristics of the core hanging basket structure obtained in the first step, the development trend of the pre-tightening degradation state of the core hanging basket is obtained. The present invention can predict the accurate changing law of the pre-tightening degradation state of the core hanging basket, laying a foundation for the establishment of a subsequent health management system for key nuclear power equipment.

[0007] The present invention is achieved through the following technical solutions:

[0008] In a first aspect, the present invention provides a method for predicting degradation of a pre-tightening state of a reactor core basket, the method comprising:

[0009] Based on static analysis and prestressed modal analysis technology, a static model of the core basket structure and a modal analysis model of the core basket are established for the core basket of a nuclear power plant. The modal analysis model of the core basket is a three-dimensional simulation model of the core basket structure under the effects of preload, support, coolant, etc.

[0010] Based on the core basket modal analysis model, the mapping relationship between the degradation state of the core basket preload state and the vibration response characteristics of the core basket structure is obtained;

[0011] According to the historical core hanging basket vibration characteristic change data, a core hanging basket vibration characteristic trend prediction model is constructed; based on the core hanging basket vibration characteristic trend prediction model, the prediction trend of the core hanging basket vibration characteristics is obtained;

[0012] According to the historical core basket vibration characteristic change data and the predicted trend of the core basket vibration characteristics, and combined with the mapping relationship between the core basket preload degradation state and the core basket structure vibration response characteristics, the predicted trend of the core basket preload degradation state is obtained.

[0013] Furthermore, based on the static analysis and prestressed modal analysis technology, a static model of the core hanging basket structure and a modal analysis model of the core hanging basket of a nuclear power plant are established, including:

[0014] The stress state of the core basket structure of a nuclear power plant is statically simplified, and a static model of the core basket structure is established;

[0015] Based on the statics model of the core basket structure, the degradation mode of the core basket preload state during the operation of the nuclear power plant is analyzed, and the statics analysis results are obtained; the statics analysis results are the influence of preload degradation on the vibration characteristics of the core basket;

[0016] According to the results of static analysis, the modal analysis model of the core basket structure under the effects of preload, support, coolant, etc. is established using finite element software.

[0017] Furthermore, the modal analysis model of the core hanging basket structure under the action of preload, support, coolant, etc. is established by using finite element software, that is, the following modeling methods are implemented by using finite element software to establish a three-dimensional simulation analysis model of the core hanging basket structure;

[0018] The modeling methods include:

[0019] Modeling method of the compression spring: The core basket and the compression spring are modeled with real physical dimensions and materials. The upper internal component model that drives the compression spring to produce constant compression deformation and the pressure vessel shoulder that provides support for the lower surface of the core basket are modeled with their real dimensions. The components are set to be in friction contact (which can fully consider the influence of friction contact force on the vibration characteristics of the core basket). A downward fixed displacement constraint is applied to the upper internal component model to compress the compression spring to generate a preload force on the core basket flange.

[0020] Modeling method for compression spring stiffness degradation simulation: Based on material mechanics and compression spring structure, a stiffness-Young's modulus substitution model for compression spring stiffness degradation simulation is derived. By reducing the Young's modulus of the compression spring material to simulate the degradation of the compression spring preload state, different degrees of compression spring stiffness degradation can be more fully simulated.

[0021] Modeling method of coolant fluid: According to the coolant flow field distribution inside the pressure vessel, a three-dimensional flow field analysis model of the reactor coolant is established, including the entire flow path of the coolant after entering the pressure vessel from the nozzle. The force of the coolant on the core basket structure is calculated by the existing fluid dynamics calculation software, and is transmitted to the surface of the core basket structure through the node fluid-solid coupling method, which can fully consider the influence of the coolant fluid flow on the vibration characteristics of the core basket;

[0022] The modeling method of the fuel assembly spring is as follows: using spring units with the same preload force, the degradation of the preload state of the spring at the top of the fuel assembly is simulated by reducing the stiffness of the spring unit, so as to consider the influence of the preload force of the fuel assembly spring on the vibration characteristics of the core basket, which is more in line with the actual situation of the boundary conditions of the core basket.

[0023] Furthermore, based on the core basket modal analysis model, the mapping relationship between the degradation state of the core basket preload state and the vibration response characteristics of the core basket structure is obtained, including:

[0024] Based on the modal analysis model of the core basket, the mapping relationship between the degradation state of the core basket preload and the vibration response characteristics of the core basket structure is obtained by simulating the degradation of the core basket preload to different degrees.

[0025] Furthermore, based on the core basket modal analysis model, by simulating different degrees of pre-tightening degradation of the core basket, the mapping relationship between the degradation state of the core basket pre-tightening state and the vibration response characteristics of the core basket structure is obtained, including:

[0026] Based on the core basket modal analysis model, the core basket prestress modal analysis under different prestressing states is carried out by simulating different degrees of prestressing degradation of the core basket; different prestressing states include the prestressing state of the compression spring and the prestressing state of the spring at the top of the fuel assembly;

[0027] According to the modal analysis of the prestress of the core hanging basket under different prestressing states, the mapping relationship between the prestressing state of the compression spring, the prestressing state of the spring at the top of the fuel assembly and the natural vibration frequency of the core hanging basket is established, that is, the mapping relationship between the degradation state of the prestressing state of the core hanging basket and the vibration response characteristics of the core hanging basket structure is established;

[0028] Wherein: by simulating different degrees of preload degradation of the core hanging basket, including: simulating the degradation of the preload state of the compression spring by reducing the Young's modulus of the compression spring material, simulating the degradation of the preload state of the spring at the top of the fuel assembly by reducing the stiffness of the spring unit at the top of the fuel assembly.

[0029] Further, the mapping relationship between the degradation state of the core hanging basket pre-tension state and the vibration response characteristics of the core hanging basket structure refers to a one-to-one correspondence between the degradation state of the core hanging basket pre-tension state and the vibration response characteristics of the core hanging basket structure.

[0030] Furthermore, the method further comprises:

[0031] Based on the vibration characteristics of the core basket obtained by analyzing and processing the neutron noise signal of the nuclear power plant, the degradation state of the core basket pre-tightening under the current operation of the equipment is mapped, that is, the degradation degree of the core basket pre-tightening state.

[0032] Furthermore, based on the historical core basket vibration characteristic change data, a core basket vibration characteristic trend prediction model is constructed, including:

[0033] Acquire the natural vibration frequency change data of the core hanging basket of the nuclear power plant during operation, and pre-process the natural vibration frequency change data of the core hanging basket; and establish a data set of natural vibration frequency change of the core hanging basket based on the pre-processed data;

[0034] A core hanging basket vibration characteristic trend prediction model was constructed using a sequence neural network. The core hanging basket vibration characteristic trend prediction model was trained based on the core hanging basket natural vibration frequency change data set to obtain a trained core hanging basket vibration characteristic trend prediction model.

[0035] In a second aspect, the present invention further provides a device for predicting degradation of a pre-tightening state of a reactor core hanging basket, the device comprising:

[0036] The analysis model building unit is used to establish a static model of the core basket structure and a core basket modal analysis model for the nuclear power plant core basket based on static analysis and prestressed modal analysis technology; the core basket modal analysis model is a three-dimensional simulation model of the core basket structure under the action of preload, support, coolant, etc.;

[0037] A mapping relationship obtaining unit, used for obtaining a mapping relationship between a degradation state of a pre-tightening state of a core hanging basket and a vibration response characteristic of a core hanging basket structure based on a core hanging basket modal analysis model;

[0038] A vibration characteristic trend prediction unit is used to construct a core hanging basket vibration characteristic trend prediction model based on historical core hanging basket vibration characteristic change data; based on the core hanging basket vibration characteristic trend prediction model, a prediction trend of the core hanging basket vibration characteristic is obtained;

[0039] The pre-tensioning degradation state prediction unit is used to obtain the prediction trend of the core hanging basket pre-tensioning degradation state according to the historical core hanging basket vibration characteristic change data and the prediction trend of the core hanging basket vibration characteristics, and in combination with the mapping relationship between the core hanging basket pre-tensioning state degradation state and the core hanging basket structure vibration response characteristics.

[0040] Furthermore, the execution process of the analysis model building unit is:

[0041] The stress state of the core basket structure of a nuclear power plant is statically simplified, and a static model of the core basket structure is established;

[0042] Based on the statics model of the core basket structure, the degradation mode of the core basket preload state during the operation of the nuclear power plant is analyzed, and the statics analysis results are obtained; the statics analysis results are the influence of preload degradation on the vibration characteristics of the core basket;

[0043] According to the results of static analysis, the modal analysis model of the core basket structure under the effects of preload, support, coolant, etc. is established using finite element software.

[0044] Furthermore, the execution process of the mapping relationship obtaining unit is:

[0045] Based on the core basket modal analysis model, the core basket prestress modal analysis under different prestressing states is carried out by simulating different degrees of prestressing degradation of the core basket; different prestressing states include the prestressing state of the compression spring and the prestressing state of the spring at the top of the fuel assembly;

[0046] According to the modal analysis of the prestress of the core hanging basket under different prestressing states, the mapping relationship between the prestressing state of the compression spring, the prestressing state of the spring at the top of the fuel assembly and the natural vibration frequency of the core hanging basket is established, that is, the mapping relationship between the degradation state of the prestressing state of the core hanging basket and the vibration response characteristics of the core hanging basket structure is established;

[0047] Wherein: by simulating different degrees of preload degradation of the core hanging basket, including: simulating the degradation of the preload state of the compression spring by reducing the Young's modulus of the compression spring material, simulating the degradation of the preload state of the spring at the top of the fuel assembly by reducing the stiffness of the spring unit at the top of the fuel assembly.

[0048] In a third aspect, the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned reactor core basket pre-tightening state degradation prediction method when executing the computer program.

[0049] In a fourth aspect, the present invention further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the above-mentioned reactor core basket pre-tightening state degradation prediction method is implemented.

[0050] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0051] 1. The method, device and medium for predicting the degradation of the pre-tightening state of the reactor core hanging basket of the present invention, first, based on static analysis and prestressed modal analysis technology, a static model of the core hanging basket structure and a modal analysis model of the core hanging basket under the action of pre-tightening force and coolant are established, and the mapping relationship between the degradation degree of the pre-tightening state of the nuclear power plant reactor core hanging basket and the vibration response characteristics of the core hanging basket structure is obtained based on the modal analysis model of the core hanging basket, so as to realize the analysis and judgment of the degradation degree of the pre-tightening state of the reactor core hanging basket; second, based on the historical core hanging basket vibration characteristic change data, a core hanging basket vibration characteristic trend prediction model is constructed to obtain the trend prediction of the core hanging basket vibration characteristics; based on the trend prediction of the core hanging basket vibration characteristics, combined with the mapping relationship between the degradation degree of the pre-tightening state of the core hanging basket obtained in the first step and the vibration response characteristics of the core hanging basket structure, the development trend of the pre-tightening degradation state of the core hanging basket is obtained. The present invention can predict the accurate change law of the pre-tightening degradation state of the core hanging basket, laying a foundation for the construction of the subsequent health management system of key nuclear power equipment.

[0052] 2. The method, device and medium for predicting the degradation of the pre-tightening state of the reactor core hanging basket of the present invention further use deep learning technology to predict the trend of the pre-tightening degradation state, so as to realize the analysis, judgment and prediction of the degradation of the pre-tightening state of the reactor core hanging basket, and ensure the normal and stable operation of the nuclear power core system. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0054] Figure 1 This is a flow chart of a method for predicting degradation of a pre-tightening state of a reactor core basket according to the present invention;

[0055] Figure 2 It is the statics model of the core hanging basket of the present invention;

[0056] Figure 3 It is a mapping table between the preload state of the compression spring and the spring at the top of the fuel assembly and the natural vibration frequency f of the core hanging basket, that is, the mapping relationship between the degradation state of the preload state of the core hanging basket and the vibration response characteristics of the core hanging basket structure;

[0057] Figure 4 It is a technical roadmap of the reactor core basket pre-tightening state degradation prediction method of the present invention;

[0058] Figure 5 This is a structural block diagram of the reactor core basket pre-tightening state degradation prediction system of the present invention. DETAILED DESCRIPTION

[0059] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0060] The present invention designs a reactor core hanging basket pre-tightening state degradation prediction method, device and medium to realize the analysis, judgment and trend prediction of the reactor core hanging basket pre-tightening state degradation of a nuclear power plant, laying a foundation for the construction of a subsequent nuclear power key equipment health management system.

[0061] First, the core basket preload state degradation analysis technology

[0062] 1. Based on static analysis and prestressed modal analysis technology, a static model of the core basket structure and a modal analysis model of the core basket under the action of preload and coolant are established; specifically:

[0063] (1) Based on the core basket of a nuclear power plant, the stress state of its structure is statically simplified and the mechanical equilibrium equation is established, that is, the static model of the core basket structure is established; through the static model of the core basket structure, the degradation mode of the preload state of the core basket during the operation of the nuclear power plant is analyzed, and the influence of preload degradation on the vibration characteristics of the core basket is obtained, that is, the static analysis result; this part is a qualitative analysis;

[0064] (2) Based on the results of static analysis, a three-dimensional simulation model of the core basket structure under the effects of preload, support, coolant, etc. is established using finite element software, namely, the core basket modal analysis model; this part is a quantitative analysis;

[0065] 2. Based on the core basket modal analysis model, by simulating different degrees of pre-tightening degradation of the core basket, the mapping relationship between the degree of degradation of the pre-tightening state of the nuclear power plant reactor core basket and the vibration response characteristics of the core basket structure is obtained, and the degree of degradation of the pre-tightening state of the reactor core basket is analyzed and judged.

[0066] Further, based on the vibration characteristics of the core basket obtained by analyzing and processing the neutron noise signal of the nuclear power plant, the pre-tightening degradation state of the core basket under the current operation of the equipment is mapped, that is, the degradation degree of the pre-tightening state of the core basket.

[0067] Second, the core basket preload degradation state trend prediction technology

[0068] The historical data of core basket vibration characteristics changes during the operation of the nuclear power plant core basket are collected, and preprocessing and data sets are established based on the historical data of core basket vibration characteristics changes; a core basket vibration characteristic trend prediction model is constructed based on deep learning technology, and model training and correction are performed to obtain the trend prediction of the core basket vibration characteristics; based on the trend prediction of the core basket vibration characteristics, the mapping relationship between the degree of degradation of the core basket pre-tightening state obtained in the first step and the vibration response characteristics of the core basket structure is combined to obtain the development trend of the core basket pre-tightening degradation state, thereby improving the accuracy of the analysis and prediction of the core basket pre-tightening degradation state. The present invention can predict the accurate change law of the core basket pre-tightening degradation state, laying a foundation for the construction of a subsequent health management system for key nuclear power equipment.

[0069] Example 1

[0070] like Figure 1 As shown, the method for predicting degradation of the pre-tightening state of the reactor core hanging basket of the present invention comprises:

[0071] Step 1: Based on static analysis and prestressed modal analysis technology, a static model of the core hanging basket structure and a modal analysis model of the core hanging basket are established for the nuclear power plant core hanging basket; the modal analysis model of the core hanging basket is a three-dimensional simulation model of the core hanging basket structure under the effects of preload, support, coolant, etc.;

[0072] Step 1 specifically includes:

[0073] Step 11, statically simplifying the stress state of the core hanging basket structure of the nuclear power plant, and establishing a static model of the core hanging basket structure;

[0074] First, the stress state of the core basket structure of the nuclear power plant is analyzed: the weight of the core basket and its fixed components is transmitted to the pressure vessel through the lower surface of the flange, and the upper surface of the core basket flange is subject to the downward preload force of the compression spring. In addition, the bottom of the core basket will be subject to the preload force from the spring on the top of the fuel assembly, and the core basket will also be subject to the force of the pressurized coolant.

[0075] Secondly, the above stress state is statically simplified and a static model is established, such as Figure 2 As shown in the figure, when the preload decreases, the downward axial force of the core basket structure will gradually decrease. When it decreases to a level that is insufficient to offset the upward axial force, the preload at the core basket flange is insufficient to limit its displacement. At this time, the flange constraint is insufficient, and the overall vibration response of the core basket will change.

[0076] Step 12, based on the statics model of the core hanging basket structure, analyzing the degradation mode of the pre-tightening state of the core hanging basket during the operation of the nuclear power plant, and obtaining a statics analysis result; the statics analysis result is the influence of pre-tightening degradation on the vibration characteristics of the core hanging basket;

[0077] Step 13, based on the static analysis results, a modal analysis model of the core hanging basket structure under the effects of preload, support, coolant, etc. is established using finite element software.

[0078] In step 13, a modal analysis model of the core hanging basket structure under the action of preload, support, coolant, etc. is established by using finite element software, which is to use the finite element software to implement the following modeling methods to establish a three-dimensional simulation analysis model of the core hanging basket structure;

[0079] The modeling methods include:

[0080] First, the modeling method of the compression spring:

[0081] Considering that the existing modeling method of the compression spring is to discretely model the compression spring as displacement constraints of multiple nodes, the preload-deformation characteristics of the structure itself and the friction contact force are not considered, the boundary conditions of the established core basket modal analysis model are quite different from the actual situation, and the modeling method is not sufficient.

[0082] The models of the core basket and the compression spring of the present invention are established with their actual physical dimensions and materials (which can fully consider the preload-deformation characteristics of the structure itself), the upper in-core component model that drives the compression spring to produce a constant compression deformation, and the pressure vessel boss that provides support for the lower surface of the core basket are both modeled with their actual dimensions, and the various components are set to be in friction contact (which can fully consider the influence of the friction contact force on the vibration characteristics of the core basket), and a fixed downward displacement constraint is applied to the upper in-core component model to compress the compression spring to produce a preload force on the core basket flange (which is consistent with the actual situation).

[0083] Second, the modeling method of compression spring stiffness degradation simulation:

[0084] Considering that the existing method is to simulate stiffness degradation by reducing the number of displacement constraints at the nodes.

[0085] The present invention derives a "stiffness-Young's modulus substitution model" for simulating the degradation of the compression spring stiffness based on material mechanics and the compression spring structure. By reducing the Young's modulus of the compression spring material to simulate the degradation of the pre-tightened state of the compression spring, it can more fully simulate the different degrees of degradation of the compression spring stiffness.

[0086] Third, how the coolant fluid is modeled:

[0087] Considering that the existing method is to load the effect of coolant fluid on structural vibration into the structural model by means of additional mass, the influence of the buoyancy brought by the upward flow of coolant fluid on the boundary conditions of the core basket is not considered, resulting in a certain deviation in the calculated results.

[0088] The present invention establishes a three-dimensional flow field analysis model of the reactor coolant based on the coolant flow field distribution inside the pressure vessel, including the entire flow path of the coolant after entering the pressure vessel from the nozzle. The force exerted by the coolant on the core basket structure is calculated using existing fluid dynamics calculation software, and is transmitted to the surface of the core basket structure through node fluid-solid coupling. This can fully consider the influence of the coolant fluid flow on the vibration characteristics of the core basket.

[0089] Fourth, the modeling method of the fuel assembly spring:

[0090] Considering that the existing methods do not consider the influence of the fuel assembly spring on the vibration characteristics of the core basket.

[0091] The top spring of the fuel assembly of the present invention is modeled as a spring unit with the same preload force. The degradation of the preload state of the top spring of the fuel assembly is simulated by reducing the stiffness of the spring unit to consider the influence of the preload force of the fuel assembly spring on the vibration characteristics of the core basket, which is more in line with the actual situation of the boundary conditions of the core basket.

[0092] The above modeling method is implemented using finite element software to establish a three-dimensional simulation analysis model of the core basket structure.

[0093] Step 2, based on the core hanging basket modal analysis model, obtain the mapping relationship between the degradation state of the core hanging basket preload state and the vibration response characteristics of the core hanging basket structure;

[0094] Step 2 includes: based on the core basket modal analysis model, by simulating different degrees of pre-tightening degradation of the core basket, obtaining the mapping relationship between the degradation state of the core basket pre-tightening state and the vibration response characteristics of the core basket structure. Specifically including:

[0095] Step 21, based on the core hanging basket modal analysis model, by simulating different degrees of pre-tightening degradation of the core hanging basket, the prestress modal analysis of the core hanging basket under different pre-tightening states is performed; the different pre-tightening states include the pre-tightening state of the compression spring and the pre-tightening state of the spring at the top of the fuel assembly; wherein: simulating different degrees of pre-tightening degradation of the core hanging basket includes: simulating the degradation of the pre-tightening state of the compression spring by reducing the Young's modulus of the compression spring material, and simulating the degradation of the pre-tightening state of the spring at the top of the fuel assembly by reducing the stiffness of the spring unit at the top of the fuel assembly;

[0096] Step 22, based on the prestress modal analysis of the core hanging basket under different prestressing states, establish a mapping relationship between the prestressing state of the compression spring, the prestressing state of the spring at the top of the fuel assembly and the natural vibration frequency of the core hanging basket, that is, a mapping relationship between the degradation state of the prestressing state of the core hanging basket and the vibration response characteristics of the core hanging basket structure.

[0097] In this embodiment, the mapping relationship between the degradation state of the core hanging basket pre-tension state and the vibration response characteristics of the core hanging basket structure refers to a one-to-one correspondence between the degradation state of the core hanging basket pre-tension state and the vibration response characteristics of the core hanging basket structure.

[0098] The present invention is based on the core hanging basket modal analysis model established in step 1, and simulates the degradation of the pre-tightening state of the compression spring by reducing the Young's modulus of the compression spring material to different degrees (for example, 3% each time, 6 times in total), and simulates the degradation of the pre-tightening state of the spring at the top of the fuel assembly by reducing the stiffness of the spring unit at different degrees (for example, 4% each time, 10 times in total), and performs prestressed modal analysis of the core hanging basket under different pre-tightening states. The obtained calculation results establish a mapping relationship between the pre-tightening state of the compression spring, the pre-tightening state of the spring at the top of the fuel assembly and the natural vibration frequency of the core hanging basket (that is, the mapping relationship between the degradation state of the pre-tightening state of the core hanging basket and the vibration response characteristics of the core hanging basket structure), such as Figure 3 Finally, based on the natural vibration frequency of the core basket obtained by analyzing and processing the neutron noise signal of the nuclear power plant, the corresponding preload status of the compression spring and the top spring of the fuel assembly is obtained by looking up the table, and the preload degradation status of the core basket under the current operation of the equipment is further analyzed and determined.

[0099] Step 3: construct a core hanging basket vibration characteristic trend prediction model based on historical core hanging basket vibration characteristic change data; based on the core hanging basket vibration characteristic trend prediction model, obtain the prediction trend of the core hanging basket vibration characteristic;

[0100] In step 3, a core hanging basket vibration characteristic trend prediction model is constructed based on the historical core hanging basket vibration characteristic change data, including:

[0101] Acquire the natural vibration frequency change data of the core hanging basket of the nuclear power plant during operation, and pre-process the natural vibration frequency change data of the core hanging basket; and establish a data set of natural vibration frequency change of the core hanging basket based on the pre-processed data;

[0102] A core hanging basket vibration characteristic trend prediction model was constructed using a sequence neural network. The core hanging basket vibration characteristic trend prediction model was trained based on the core hanging basket natural vibration frequency change data set to obtain a trained core hanging basket vibration characteristic trend prediction model.

[0103] Step 3 of the present invention collects the data of the natural vibration frequency change of the core hanging basket of the nuclear power plant during operation, performs preprocessing on the data such as Gaussian filtering and data normalization, and establishes a data set of the natural vibration frequency change of the core hanging basket; uses a sequence neural network such as LSTM to establish a prediction model for the change trend of the natural vibration frequency of the core hanging basket (i.e., a prediction model for the vibration characteristic trend of the core hanging basket), and the model schematic diagram is shown in FIG. Figure 4As shown, training and correction are carried out, and finally the trend prediction of the natural vibration frequency of the core basket is realized, and the vibration frequency trend prediction result is obtained.

[0104] Step 4: According to the historical core basket vibration characteristic change data and the predicted trend of the core basket vibration characteristics, and in combination with the mapping relationship between the core basket preload state degradation state and the core basket structure vibration response characteristics, the predicted trend of the core basket preload degradation state is obtained.

[0105] Based on the vibration frequency trend prediction results, combined with Figure 3 The mapping relationship shown in the figure is used to analyze and determine the preload status of the compression spring and the spring on the top of the fuel assembly corresponding to each trend point of the natural vibration frequency of the core hanging basket, so as to realize the trend prediction of the preload degradation status of the core hanging basket and lay the foundation for the subsequent construction of the health management system for key nuclear power equipment.

[0106] Figure 4 The technical roadmap of the reactor core basket preload state degradation prediction method. The method of the present invention first establishes a static model of the core basket structure based on static analysis to obtain the influence of the preload mode on the core basket movement, and then establishes a modal analysis model of the core basket under the direct action of the preload force and the coolant based on the finite element numerical solution method to obtain the influence of the preload force degradation on the vibration behavior of the core basket, and establishes a mapping relationship between the degree of degradation of the preload state of the nuclear power plant reactor core basket and the vibration response characteristics of the core basket structure, and further uses deep learning technology to predict the trend of the preload degradation state, so as to realize the analysis, judgment and prediction of the degradation of the reactor core basket preload state, and ensure the normal and stable operation of the nuclear power core system.

[0107] Example 2

[0108] like Figure 5 As shown, the difference between this embodiment and embodiment 1 is that this embodiment further provides a device for predicting degradation of the pre-tightening state of the reactor core hanging basket, and the function of the device corresponds to the method for predicting degradation of the pre-tightening state of the reactor core hanging basket in embodiment 1; the device comprises:

[0109] The analysis model building unit is used to establish a static model of the core basket structure and a core basket modal analysis model for the nuclear power plant core basket based on static analysis and prestressed modal analysis technology; the core basket modal analysis model is a three-dimensional simulation model of the core basket structure under the action of preload, support, coolant, etc.;

[0110] A mapping relationship obtaining unit, used for obtaining a mapping relationship between a degradation state of a pre-tightening state of a core hanging basket and a vibration response characteristic of a core hanging basket structure based on a core hanging basket modal analysis model;

[0111] A vibration characteristic trend prediction unit is used to construct a core hanging basket vibration characteristic trend prediction model based on historical core hanging basket vibration characteristic change data; based on the core hanging basket vibration characteristic trend prediction model, a prediction trend of the core hanging basket vibration characteristic is obtained;

[0112] The pre-tensioning degradation state prediction unit is used to obtain the prediction trend of the core hanging basket pre-tensioning degradation state according to the historical core hanging basket vibration characteristic change data and the prediction trend of the core hanging basket vibration characteristics, and in combination with the mapping relationship between the core hanging basket pre-tensioning state degradation state and the core hanging basket structure vibration response characteristics.

[0113] As a further implementation, the execution process of the analysis model building unit is:

[0114] The stress state of the core basket structure of a nuclear power plant is statically simplified, and a static model of the core basket structure is established;

[0115] Based on the statics model of the core basket structure, the degradation mode of the core basket preload state during the operation of the nuclear power plant is analyzed, and the statics analysis results are obtained; the statics analysis results are the influence of preload degradation on the vibration characteristics of the core basket;

[0116] According to the results of static analysis, the modal analysis model of the core basket structure under the effects of preload, support, coolant, etc. is established using finite element software.

[0117] As a further implementation, the execution process of the mapping relationship obtaining unit is:

[0118] Based on the core basket modal analysis model, the core basket prestress modal analysis under different prestressing states is carried out by simulating different degrees of prestressing degradation of the core basket; different prestressing states include the prestressing state of the compression spring and the prestressing state of the spring at the top of the fuel assembly;

[0119] According to the modal analysis of the prestress of the core hanging basket under different prestressing states, the mapping relationship between the prestressing state of the compression spring, the prestressing state of the spring at the top of the fuel assembly and the natural vibration frequency of the core hanging basket is established, that is, the mapping relationship between the degradation state of the prestressing state of the core hanging basket and the vibration response characteristics of the core hanging basket structure is established;

[0120] Wherein: by simulating different degrees of preload degradation of the core hanging basket, including: simulating the degradation of the preload state of the compression spring by reducing the Young's modulus of the compression spring material, simulating the degradation of the preload state of the spring at the top of the fuel assembly by reducing the stiffness of the spring unit at the top of the fuel assembly.

[0121] Among them, the execution process of each unit can be executed according to the process steps of the reactor core hanging basket pre-tightening state degradation prediction method in Example 1, and will not be repeated in this embodiment.

[0122] At the same time, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned reactor core basket pre-tightening state degradation prediction method is implemented.

[0123] At the same time, the present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the above-mentioned reactor core basket pre-tightening state degradation prediction method is implemented.

[0124] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0125] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0126] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0127] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1The steps for the functions specified in one or more boxes.

[0128] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for predicting degradation of the pre-tightening state of a reactor core basket, characterized in that: The method includes: Based on static analysis and prestressed modal analysis technology, a static model of the core hanging basket structure and a modal analysis model of the core hanging basket are established for the core hanging basket of a nuclear power plant; the modal analysis model of the core hanging basket is a three-dimensional simulation model of the core hanging basket structure under the action of preload, support and coolant; Based on the core hanging basket modal analysis model, a mapping relationship between a degradation state of a core hanging basket preload state and a vibration response characteristic of a core hanging basket structure is obtained; According to the historical core hanging basket vibration characteristic change data, a core hanging basket vibration characteristic trend prediction model is constructed; based on the core hanging basket vibration characteristic trend prediction model, a prediction trend of the core hanging basket vibration characteristic is obtained; According to the historical core hanging basket vibration characteristic change data and the predicted trend of the core hanging basket vibration characteristics, and combined with the mapping relationship between the core hanging basket pre-tightening state degradation state and the core hanging basket structure vibration response characteristics, the predicted trend of the core hanging basket pre-tightening degradation state is obtained.

2. The method for predicting degradation of the pre-tightening state of the reactor core hanging basket according to claim 1, characterized in that: Based on static analysis and prestressed modal analysis technology, a static model of the core basket structure and a modal analysis model of the core basket are established for the nuclear power plant core basket, including: The stress state of the core basket structure of a nuclear power plant is statically simplified, and a static model of the core basket structure is established; Based on the statics model of the core hanging basket structure, the degradation mode of the pre-tightening state of the core hanging basket during the operation of the nuclear power plant is analyzed to obtain statics analysis results; the statics analysis results are the influence of pre-tightening degradation on the vibration characteristics of the core hanging basket; According to the static analysis results, a modal analysis model of the core hanging basket structure under the action of preload, support and coolant is established using finite element software.

3. The method for predicting degradation of the pre-tightening state of the reactor core hanging basket according to claim 2, characterized in that: The modal analysis model of the core basket structure under the action of preload, support and coolant is established by using finite element software. The following modeling methods are implemented by using finite element software to establish a three-dimensional simulation analysis model of the core basket structure. The modeling methods include: Modeling method of the compression spring: The core basket and the compression spring are modeled with real physical dimensions and materials. The upper internal component model that drives the compression spring to produce constant compression deformation and the pressure vessel shoulder that provides support for the lower surface of the core basket are modeled with their real dimensions. The components are set to be in friction contact, and a downward fixed displacement constraint is applied to the upper internal component model to compress the compression spring to generate a preload force on the core basket flange. Modeling method for compression spring stiffness degradation simulation: Based on material mechanics and compression spring structure, a stiffness-Young's modulus substitution model for compression spring stiffness degradation simulation is derived, and the degradation of the compression spring preload state is simulated by reducing the Young's modulus of the compression spring material; Modeling method of coolant fluid: According to the coolant flow field distribution inside the pressure vessel, a three-dimensional flow field analysis model of the reactor coolant is established, including the entire flow path of the coolant after entering the pressure vessel from the nozzle. The force of the coolant on the core basket structure is calculated by the existing fluid dynamics calculation software, and is transmitted to the surface of the core basket structure through the node fluid-solid coupling method; The fuel assembly spring is modeled in the following way: using spring units with the same preload force, the degradation of the preload state of the spring at the top of the fuel assembly is simulated by reducing the stiffness of the spring unit.

4. The method for predicting degradation of the pre-tightening state of the reactor core hanging basket according to claim 1, characterized in that: Based on the core hanging basket modal analysis model, a mapping relationship between the degradation state of the core hanging basket preload state and the vibration response characteristics of the core hanging basket structure is obtained, including: Based on the core hanging basket modal analysis model, by simulating different degrees of pre-tightening degradation of the core hanging basket, a mapping relationship between the degradation state of the core hanging basket pre-tightening state and the vibration response characteristics of the core hanging basket structure is obtained.

5. The method for predicting degradation of the pre-tightening state of the reactor core hanging basket according to claim 4, characterized in that: Based on the core hanging basket modal analysis model, by simulating different degrees of pre-tightening degradation of the core hanging basket, a mapping relationship between the degradation state of the core hanging basket pre-tightening state and the vibration response characteristics of the core hanging basket structure is obtained, including: Based on the core hanging basket modal analysis model, by simulating different degrees of prestressing degradation of the core hanging basket, a prestressing modal analysis of the core hanging basket under different prestressing states is performed; the different prestressing states include a compression spring prestressing state and a fuel assembly top spring prestressing state; According to the modal analysis of the prestress of the core hanging basket under different prestressing states, the mapping relationship between the prestressing state of the compression spring, the prestressing state of the spring at the top of the fuel assembly and the natural vibration frequency of the core hanging basket is established, that is, the mapping relationship between the degradation state of the prestressing state of the core hanging basket and the vibration response characteristics of the core hanging basket structure is established; Wherein: by simulating different degrees of preload degradation of the core hanging basket, including: simulating the degradation of the preload state of the compression spring by reducing the Young's modulus of the compression spring material, simulating the degradation of the preload state of the spring at the top of the fuel assembly by reducing the stiffness of the spring unit at the top of the fuel assembly.

6. The method for predicting degradation of the pre-tightening state of the reactor core hanging basket according to claim 1, characterized in that: The mapping relationship between the degradation state of the core hanging basket pre-tightening state and the vibration response characteristics of the core hanging basket structure refers to a one-to-one correspondence between the degradation state of the core hanging basket pre-tightening state and the vibration response characteristics of the core hanging basket structure.

7. The method for predicting degradation of the pre-tightening state of the reactor core hanging basket according to claim 1, characterized in that: The method further includes: Based on the vibration characteristics of the core basket obtained by analyzing and processing the neutron noise signal of the nuclear power plant, the degradation state of the core basket pre-tightening under the current operation of the equipment is mapped, that is, the degradation degree of the core basket pre-tightening state.

8. The method for predicting degradation of the pre-tightening state of the reactor core hanging basket according to claim 1, characterized in that: Based on the historical core basket vibration characteristic change data, a core basket vibration characteristic trend prediction model is constructed, including: Acquire the natural vibration frequency change data of the core hanging basket of the nuclear power plant during operation, and pre-process the natural vibration frequency change data of the core hanging basket; and establish a data set of natural vibration frequency change of the core hanging basket based on the pre-processed data; A core hanging basket vibration characteristic trend prediction model is constructed by using a sequence neural network, and the core hanging basket vibration characteristic trend prediction model is trained based on the core hanging basket natural vibration frequency change data set to obtain a trained core hanging basket vibration characteristic trend prediction model.

9. A reactor core hanging basket preload state degradation prediction device, characterized in that: The device includes: An analysis model building unit is used to establish a static model of a core hanging basket structure and a core hanging basket modal analysis model for a core hanging basket of a nuclear power plant based on static analysis and prestressed modal analysis technology; the core hanging basket modal analysis model is a three-dimensional simulation model of the core hanging basket structure under the action of preload, support, and coolant; A mapping relationship obtaining unit, used for obtaining a mapping relationship between a degradation state of a pre-tightening state of a core hanging basket and a vibration response characteristic of a core hanging basket structure based on the core hanging basket modal analysis model; A vibration characteristic trend prediction unit is used to construct a core hanging basket vibration characteristic trend prediction model according to historical core hanging basket vibration characteristic change data; based on the core hanging basket vibration characteristic trend prediction model, a prediction trend of the core hanging basket vibration characteristic is obtained; The pre-tensioning degradation state prediction unit is used to obtain the prediction trend of the core hanging basket pre-tensioning degradation state according to the historical core hanging basket vibration characteristic change data and the prediction trend of the core hanging basket vibration characteristics, and in combination with the mapping relationship between the core hanging basket pre-tensioning state degradation state and the core hanging basket structure vibration response characteristics.

10. The reactor core hanging basket pre-tightening state degradation prediction device according to claim 9, characterized in that: The execution process of the analysis model building unit is: The stress state of the core basket structure of a nuclear power plant is statically simplified, and a static model of the core basket structure is established; Based on the statics model of the core hanging basket structure, the degradation mode of the pre-tightening state of the core hanging basket during the operation of the nuclear power plant is analyzed to obtain statics analysis results; the statics analysis results are the influence of pre-tightening degradation on the vibration characteristics of the core hanging basket; According to the static analysis results, a modal analysis model of the core hanging basket structure under the action of preload, support and coolant is established using finite element software.

11. The reactor core hanging basket preload state degradation prediction device according to claim 9, characterized in that: The execution process of the mapping relationship obtaining unit is as follows: Based on the core hanging basket modal analysis model, by simulating different degrees of prestressing degradation of the core hanging basket, a prestressing modal analysis of the core hanging basket under different prestressing states is performed; the different prestressing states include a compression spring prestressing state and a fuel assembly top spring prestressing state; According to the modal analysis of the prestress of the core hanging basket under different prestressing states, the mapping relationship between the prestressing state of the compression spring, the prestressing state of the spring at the top of the fuel assembly and the natural vibration frequency of the core hanging basket is established, that is, the mapping relationship between the degradation state of the prestressing state of the core hanging basket and the vibration response characteristics of the core hanging basket structure is established; Wherein: by simulating different degrees of preload degradation of the core hanging basket, including: simulating the degradation of the preload state of the compression spring by reducing the Young's modulus of the compression spring material, simulating the degradation of the preload state of the spring at the top of the fuel assembly by reducing the stiffness of the spring unit at the top of the fuel assembly.

12. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for predicting degradation of the pre-tightening state of a reactor core basket according to any one of claims 1 to 8 is implemented.

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