Analysis method and system for failure probability of silicon carbide pressurized water reactor fuel rod cladding

Abstract

The invention provides a silicon carbide pressurized water reactor fuel rod cladding failure probability analysis method and system. The method comprises the following steps: S1, establishing a Weibull probability distribution intensity model of a silicon carbide cladding material; s2, establishing a fuel rod single-rod analysis finite element model, wherein the fuel rod single-rod analysis finite element model is used for performing in-pile irradiation-heat transfer-mechanical coupling behavior analysis of the fuel rod; s3, sampling the power history of the fuel rods at different positions of the reactor core and / or the dimensional tolerance of geometric structure parameters of the fuel rods; s4, a sampling result is input into the fuel rod single rod analysis finite element model for calculation, and distribution of a stress field of the silicon carbide cladding along with time change is obtained; and S5, based on the Weibull probability distribution intensity model and the stress field of the silicon carbide cladding, calculating the cumulative failure probability of the whole silicon carbide cladding in each time step, and obtaining the distribution of the failure probability of the silicon carbide cladding along with time.

Description

Technical Field

[0001] This application mainly relates to the field of nuclear reactor fuel element safety analysis technology, and in particular to an analysis method, system, equipment and storage medium for the failure probability of fuel rod cladding in silicon carbide pressurized water reactors. Background Technology

[0002] Zirconium alloys are commonly used as fuel rod cladding materials in pressurized water reactor nuclear power plants. However, under severe accident conditions, zirconium alloys oxidize rapidly in high-temperature steam, generating large amounts of heat and hydrogen, which may exacerbate the accident's consequences. Therefore, the concept of Accident Tolerant Fuel (ATF) has been proposed. Among these, silicon carbide is considered a highly promising ATF cladding material due to its high-temperature mechanical properties, chemical stability, excellent resistance to high-temperature water and steam oxidation, low heat release during reaction, and good neutron economy.

[0003] However, silicon carbide cladding, as a ceramic material, is a typical brittle material, and its strength is significantly affected by randomly distributed microscopic defects (such as microcracks, pores, and inclusions) within the material. These internal microscopic defects are prone to crack propagation under stress, ultimately leading to macroscopic failure of the material. This means that the strength of silicon carbide cladding is not a fixed value, but rather is dominated by the "weakest link theory," exhibiting significant dispersion.

[0004] Existing zirconium alloy cladding for pressurized water reactors is a metallic material, exhibiting ductile fracture. Its fracture characteristics are typically characterized using deterministic effective stress or strain energy density, which is fundamentally different from the failure modes of silicon carbide ceramic cladding. Therefore, there is an urgent need to develop a failure probability analysis method that can effectively characterize the strength dispersion of silicon carbide cladding, replacing and innovating existing ductile fracture analysis methods applicable to zirconium alloy cladding. This would provide crucial technical support for the safe application and reliability assessment of silicon carbide cladding in pressurized water reactors. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method, system, device and storage medium that can quantitatively assess the failure probability of silicon carbide cladding under reactor operating conditions.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for analyzing the failure probability of fuel rod cladding in a silicon carbide pressurized water reactor, comprising the following steps:

[0008] Step S1: Establish the Weibull probability distribution intensity model of the silicon carbide cladding material;

[0009] Step S2: Establish a finite element model for single fuel rod analysis. The finite element model is used to analyze the in-pile irradiation-heat transfer-mechanical coupling behavior of the fuel rod.

[0010] Step S3: Sampling of the dimensional tolerances of the fuel rod power history and / or fuel rod geometry parameters at different locations in the reactor core;

[0011] Step S4: Input the sampling results into the single-bar analysis finite element model of the fuel rod for calculation to obtain the distribution of stress field of silicon carbide cladding over time;

[0012] Step S5: Based on the Weibull probability distribution intensity model and the stress field of the silicon carbide cladding, calculate the cumulative failure probability of the entire silicon carbide cladding at each time step, and obtain the distribution of the failure probability of the silicon carbide cladding over time.

[0013] Secondly, the present invention provides a silicon carbide pressurized water reactor fuel rod cladding failure probability analysis system, comprising:

[0014] The sampling and input module is configured to sample the power history of fuel rods and / or the dimensional tolerances of fuel rod geometric parameters at different locations in the reactor core, and input the sampling results into the finite element analysis module.

[0015] The finite element analysis module is configured to build a single-bar finite element model of the fuel rod for performing in-pile irradiation-heat transfer-mechanical coupling behavior analysis to calculate the stress field of the silicon carbide cladding.

[0016] The failure probability calculation module is configured to receive the silicon carbide cladding stress field output by the finite element analysis module, and calculate the cumulative failure probability of the entire silicon carbide cladding based on the pre-stored Weibull probability distribution intensity model of the silicon carbide cladding material.

[0017] Thirdly, the present invention provides a computer device including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method described in any one of the first aspects above.

[0018] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in any one of the first aspects above.

[0019] Compared with the prior art, this application has the following advantages:

[0020] This application proposes a method for analyzing the failure probability of silicon carbide pressurized water reactor fuel rod cladding. This method combines finite element mechanical analysis with the Weibull statistical probability model to predict the failure probability of silicon carbide cladding under reactor operating conditions, solving the reliability assessment problem caused by the strength dispersion of silicon carbide cladding. Secondly, this application establishes a multi-physics field coupling analysis finite element model of fuel rod single rod that considers irradiation effects, pellet-cladding mechanical interactions, fission gas release, and internal pressure changes. This model can accurately simulate the stress response of the cladding in a complex reactor environment, providing a reliable input for probability assessment. Attached Figure Description

[0021] The accompanying drawings are included to provide a further understanding of this application. They are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of this application.

[0022] Figure 1 This is a flowchart of a method for analyzing the failure probability of fuel rod cladding in a silicon carbide pressurized water reactor according to an embodiment of this application.

[0023] Figure 2 This is a flowchart illustrating the establishment of a single-bar finite element model for fuel rod analysis according to an embodiment of this application.

[0024] Figure 3 This is a schematic diagram of an analysis system for the failure probability of fuel rod cladding in a silicon carbide pressurized water reactor according to an embodiment of this application.

[0025] Figure 4 This is a system block diagram of a computer device according to an embodiment of this application. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0027] Figure 1 This is a flowchart illustrating a method for analyzing the failure probability of fuel rod cladding in a silicon carbide pressurized water reactor according to an embodiment of this application. Figure 1 As shown, the analysis method 100 for the failure probability of fuel rod cladding in a silicon carbide pressurized water reactor includes:

[0028] Step S1: Establish the Weibull probability distribution intensity model of the silicon carbide cladding material.

[0029] The Weibull probability distribution strength model is a probability distribution model widely used in reliability engineering and failure analysis to describe the statistical laws governing the "life" or "strength" of materials or products. Its core idea is that the failure of a system is determined by its weakest link. This is known as the "weakest link model."

[0030] In this application, micro-defects (such as microcracks and pores) are randomly distributed inside the silicon carbide cladding. The purpose of the Weibull probability distribution strength model is to establish a mathematical relationship between the applied stress and the probability that the cladding will fracture due to these defects.

[0031] In one embodiment, the Weibull probability distribution intensity model is established in the following manner:

[0032] Fracture strength data of silicon carbide cladding materials were obtained through materials mechanics experiments (such as tensile, bending, and C-ring tests). Based on the fracture strength data, a Weibull probability distribution function was obtained. The Weibull probability distribution function is as follows:

[0033]

[0034] in, This represents the probability of failure. For the applied stress, For Weibull characteristic intensity, It is the Weibull modulus.

[0035] Step S2: Establish a single-bar finite element model for fuel rod analysis. This single-bar finite element model is used to analyze the coupled behavior of fuel rods in the reactor core, including irradiation, heat transfer, and mechanical processes.

[0036] In one embodiment, a single-rod finite element model of the fuel rod is established using the finite element software ABAQUS, which can be used for the analysis of the coupled behavior of irradiation, heat transfer, and mechanical processes within the fuel rod reactor. Figure 2 As shown, the steps for establishing a single-bar finite element model for fuel rod analysis are as follows:

[0037] Step S21: Establish a finite element geometric model based on the geometric parameters of the fuel rods.

[0038] The geometric parameters of the fuel rod include, but are not limited to, the inner diameter of the cladding, the outer diameter of the cladding, the outer diameter of the pellet, the height of the active zone, the volume of the gas chamber, and the volume of the fuel rod cavity.

[0039] Step S22: Set material property parameters for the core and cladding regions in the finite element geometric model.

[0040] Material properties include, but are not limited to, the elastic modulus, Poisson's ratio, coefficient of thermal expansion, thermal conductivity, and specific heat of the core and cladding.

[0041] Preferably, to accurately simulate irradiation damage, it is also necessary to define irradiation effects related to burnup, such as pellet compaction and swelling, and cladding swelling and creep. Since the physical properties of the pellet and cladding materials are affected by irradiation and are usually related to burnup, the UMAT and UMATHT subroutines of ABAQUS are preferably used for definition.

[0042] Step S23: Mesh generation, select thermally coupled C3D8RT element as the mesh type.

[0043] Step S24: Set the analysis time step, and set the analysis time step type to thermo-mechanical coupling analysis step.

[0044] Step S25: Set the outer surface of the core and the inner surface of the cladding as a contact pair.

[0045] The contact properties can be set to limited slip or hard contact to simulate the mechanical interaction between the core and the cladding.

[0046] Step S26: Set up a fluid cavity inside the finite element geometric model to simulate the internal pressure of the fuel rod.

[0047] The gas in the fluid cavity includes fuel rod pre-charge gas and fission gas. Fission gas release is related to temperature and burnup, and a modified Forsberg-Massih model can be used for calculation. The amount of fission gas released for each pellet cell is calculated separately, and the amount released into the fuel rod cavity volume is obtained by integrating over all pellets.

[0048] The gas in the fluid cavity satisfies the modified van der Waals equation:

[0049]

[0050] in,

[0051] : Internal pressure of fuel rods;

[0052] The volume of the fuel rod cavity can be read using an ABAQUS sensor.

[0053] 0.6, dimensionless constant;

[0054] : van der Waals constant, 8.5 × 10 -29 m 3 ;

[0055] : Number of gas atoms in the fluid cavity;

[0056] Boltzmann constant, 1.381 × 10⁻⁶ -23 J / K;

[0057] Temperature, K.

[0058] Step S27: Set loads and boundary conditions.

[0059] The bottom of the fuel rod is set to a fixed boundary condition.

[0060] The outer surface of the casing is set as the boundary condition for coolant pressure load and convective heat transfer between the casing and the coolant.

[0061] The volumetric calorific rate of the fuel cell is set. Considering the distribution of the volumetric calorific rate of the fuel cell along the radial direction of the fuel cell and the axial direction of the fuel rod, the DFLUX subroutine of ABAQUS is used to set the volumetric calorific rate that varies with space.

[0062] The inner surface of the cladding is subjected to the internal pressure load of the fuel rods, which is the fluid cavity pressure calculated in step 25. Considering that the internal pressure of the fuel rods varies with fuel consumption and has a strong coupling with temperature and mechanical deformation, the DLOAD subroutine of ABAQUS is used for setting.

[0063] The finite element model in this invention is not an ordinary mechanical analysis model. It is a high-fidelity, multi-physics dynamically coupled digital twin specifically constructed for the novel purpose of 'quantitatively assessing the failure probability of brittle silicon carbide cladding'.

[0064] First, the time-varying behavior of the simulated materials within the reactor as burnup changes directly affects the stress distribution. This application considers the material properties of irradiation effects (such as pellet compaction / swelling and cladding creep), transforming the model from a static simulation to a dynamic evolution simulation. The output stress field changes realistically over time, providing accurate time-varying input for probabilistic calculations, which is the foundation for achieving dynamic probabilistic assessment.

[0065] Secondly, this application establishes a core-cladding contact pair to accurately simulate the core-cladding mechanical interaction (PCI), a key factor leading to cladding stress. Traditional analyses may simplify this contact, but this application treats it as an essential feature, ensuring the accuracy of stress field calculations, especially the tensile stresses that lead to brittle fracture.

[0066] Furthermore, this application establishes a fluid cavity and couples the release of fission gas with the calculation of internal pressure. It simulates time-varying internal pressure loads, one of the main sources of cladding stress, and strongly correlates with fuel consumption. By strongly coupling thermo-mechanical analysis and internal pressure calculations through van der Waals equations, the model reflects the true load history, rather than applying a constant pressure. This is also essential for obtaining an accurate time-varying stress field.

[0067] The core purpose of the finite element model in this application is to provide high-fidelity, time-varying stress field input for subsequent Weibull probability models. This model is not an isolated mechanical model, but rather the core data generator for a larger, innovative "physics-probabilistic" hybrid analysis system. Its construction concept, accuracy requirements, and output objectives are all tailored to serve probabilistic assessment.

[0068] The finite element model in this application is not a simple listing of individual features, but rather an organically synergistic whole: the irradiation effect influences the pellet size and cladding performance, thereby altering the PCI contact state and internal pressure, collectively determining the instantaneous stress field of the cladding. This stress field is input into the Weibull model to calculate the instantaneous failure probability. This is an interconnected and tightly coupled technical chain. The ultimate technical effect is a shift from deterministic safety analysis of zirconium alloys to probabilistic reliability assessment of silicon carbide. This provides a novel and crucial quantitative tool for the design and safety review of accident-resistant fuels.

[0069] Step S3: Sampling of the dimensional tolerances of the fuel rod power history and / or fuel rod geometry parameters at different locations in the reactor core;

[0070] Step S4: Input the sampling results into the finite element model for single-bar analysis of fuel rods for calculation to obtain the distribution of stress field of silicon carbide cladding over time.

[0071] Random sampling is performed on the power history experienced by fuel rods at different locations in the reactor core, as well as the dimensional tolerances of the geometric parameters during the fuel rod manufacturing process. Each sampling combination is used as input conditions to drive the finite element model established in step S2 to perform calculations, thereby obtaining the distribution of the stress field of the silicon carbide cladding over time under this specific operating condition.

[0072] Preferably, the stress field of the silicon carbide cladding is the first principal stress field. In mechanics of materials and continuum mechanics, any point within an object experiences three mutually perpendicular principal stresses in three-dimensional space, arranged algebraically as the first principal stress, the second principal stress, and the third principal stress. The first principal stress is the maximum tensile stress at that point. For brittle materials like silicon carbide, fracture is primarily caused by tensile stress. Microcracks propagate most easily under tensile stress, leading to material failure.

[0073] Step S5: Based on the Weibull probability distribution intensity model and the stress field of the silicon carbide cladding, calculate the cumulative failure probability of the entire silicon carbide cladding at each time step, and obtain the distribution of the failure probability of the silicon carbide cladding over time.

[0074] For each time step of the finite element calculation results, the calculated cladding stress field (i.e., the stress value of each element) is substituted into the Weibull probability distribution strength model established in step S1. For each finite element of the cladding, its element failure probability at that stress level is calculated. Then, the failure probabilities of all elements are combined using a numerical integration method (such as multiplication) to obtain the cumulative failure probability of the entire cladding at that time step. Repeating this process yields the distribution curve of the cladding failure probability over time, thereby enabling dynamic assessment of the cladding's full life-cycle reliability.

[0075] This application addresses the issue that the fracture strength of silicon carbide cladding is not a fixed value but exhibits dispersion. It proposes a method for analyzing the failure probability of silicon carbide pressurized water reactor fuel rod cladding. This method combines finite element analysis with the Weibull statistical probability model to predict the failure probability of silicon carbide cladding under reactor operating conditions. It considers the effects of irradiation and the interaction between the fuel pellets and the cladding. The method encompasses processes such as the Weibull probability distribution strength model, the finite element model for single fuel rod analysis, core power history and dimensional tolerance sampling of fuel rod geometric parameters, and the calculation of the cumulative failure probability of silicon carbide cladding. This method solves the reliability assessment problem caused by the dispersion of silicon carbide cladding strength and fills a gap in existing technologies in this field.

[0076] Figure 3 This is a schematic diagram of an analysis system for the failure probability of cladding fuel rods in a silicon carbide pressurized water reactor according to an embodiment of this application. Figure 3 As shown, the analysis system 300 for the failure probability of silicon carbide pressurized water reactor fuel rod cladding includes a sampling and input module 31, a finite element analysis module 32, and a failure probability calculation module 33.

[0077] The sampling and input module 31 is configured to sample the power history of fuel rods and / or the dimensional tolerances of fuel rod geometric parameters at different locations in the reactor core, and input the sampling results to the finite element analysis module 32.

[0078] The finite element analysis module 32 is configured to establish a single-bar finite element model for fuel rod analysis, which is used to perform in-pile irradiation-heat transfer-mechanical coupling behavior analysis to calculate the stress field of silicon carbide cladding;

[0079] The failure probability calculation module 33 is configured to receive the silicon carbide cladding stress field output by the finite element analysis module 32, and calculate the cumulative failure probability of the entire silicon carbide cladding based on the built-in Weibull probability distribution intensity model 331 of the silicon carbide cladding material.

[0080] This application also provides a computer device 400. For example... Figure 4As shown, the computer device 400 includes a bus 401, a processor 402, a memory 404, and a communication interface 403. The processor 402, the memory 404, and the communication interface 403 communicate with each other via the bus 401. The computer device 400 can be a server or a terminal device. It should be understood that this application does not limit the number of processors and memories in the computer device 400.

[0081] Bus 401 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, Figure 4 The bus 401 may be represented by a single line, but this does not mean that there is only one bus or one type of bus. The bus 401 may include a path for transmitting information between various components of the computer device 400 (e.g., memory 404, processor 402, communication interface 403).

[0082] Processor 402 may include any one or more processors such as a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor (MP), or a digital signal processor (DSP).

[0083] Memory 404 may include volatile memory, such as random access memory (RAM). Processor 402 may also include non-volatile memory, such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid state drive (SSD).

[0084] The memory 404 stores executable program code, which the processor 402 executes to implement the aforementioned analysis method for the failure probability of silicon carbide pressurized water reactor fuel rods. That is, the memory 404 stores instructions for executing the analysis method for the failure probability of silicon carbide pressurized water reactor fuel rods.

[0085] The communication interface 403 uses transceiver modules such as, but not limited to, network interface cards and transceivers to enable communication between the computer device 400 and other devices or communication networks.

[0086] This application also provides a computer program product containing instructions. The computer program product may be software or program products containing instructions, capable of running on a computer device or stored on any usable medium. When the computer program product is run on at least one computer device, it causes the at least one computer device to execute a method for analyzing the failure probability of the fuel rod cladding in a silicon carbide pressurized water reactor.

[0087] This application also provides a computer-readable storage medium. The computer-readable storage medium can be any available medium that a computer device can store, or a data storage device such as a data center containing one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive). The computer-readable storage medium includes instructions that instruct a computer device to execute a method for analyzing the failure probability of the fuel rod cladding in a silicon carbide pressurized water reactor.

[0088] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0089] Flowcharts are used in this application to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, various steps can be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

[0091] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0092] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method of analyzing failure probability of a silicon carbide pressure water reactor fuel rod cladding, characterized by, The method comprises: Step S1: establishing a Weibull probability distribution strength model of the silicon carbide cladding material; Step S2: establishing a fuel rod single-rod analysis finite element model, the fuel rod single-rod analysis finite element model being used for performing in-pile irradiation-heat transfer-mechanical coupling behavior analysis of the fuel rod; Step S3: sampling the fuel rod power history at different positions of the reactor core and / or the size tolerance of the fuel rod geometric structure parameters; Step S4: inputting the sampling results into the fuel rod single-rod analysis finite element model for calculation to obtain the distribution of the stress field of the silicon carbide cladding with time; Step S5: based on the Weibull probability distribution strength model and the stress field of the silicon carbide cladding, calculating the cumulative failure probability of the entire silicon carbide cladding at each time step to obtain the distribution of the failure probability of the silicon carbide cladding with time.

2. The method of claim 1, wherein, In step S1, the Weibull probability distribution strength model is established by: obtaining the fracture strength data of the silicon carbide cladding material through material mechanics experiments, and fitting a Weibull probability distribution function based on the fracture strength data, the Weibull probability distribution function being: wherein is the failure probability, is the applied stress, is the Weibull characteristic strength, is the Weibull modulus.

3. The method of claim 1, wherein, In step S2, establishing the fuel rod single-rod analysis finite element model comprises: establishing a finite element geometric model based on the geometric structure parameters of the fuel rod; setting material physical property parameters for the pellet and cladding regions in the finite element geometric model; setting a contact pair between the outer surface of the pellet and the inner surface of the cladding in the finite element geometric model; setting a fluid cavity inside the finite element geometric model to simulate the internal pressure of the fuel rod.

4. The method of claim 3, wherein, Setting the material physical property parameters comprises: defining irradiation effects related to burnup, the irradiation effects including at least one of pellet densification, pellet swelling, and cladding creep.

5. The method of claim 3, wherein, Simulating the internal pressure of the fuel rod comprises: calculating a gas pressure contributed by the pre-charged gas and the fission gas together, and taking the gas pressure as the internal pressure of the fuel rod, wherein the release amount of the fission gas is calculated based on the temperature and burnup of the pellet.

6. The method of claim 5, wherein, The gas pressure is calculated based on a modified van der Waals equation, the equation being: wherein, is the fuel rod internal pressure, is the fuel rod cavity volume, is a constant, is the van der Waals constant, is the number of fluid cavity gas atoms, is the Boltzmann constant, is the temperature.

7. The method of claim 3, wherein, The method further comprises setting loads and boundary conditions, comprising: applying coolant pressure and convective heat transfer boundary conditions on the outer surface of the cladding; setting a spatially-distributed volumetric heat generation rate on the pellet; applying the calculated internal pressure of the fuel rod as a load to the inner surface of the cladding.

8. The method of claim 3, wherein, The fuel rod single-rod analysis finite element geometric model is meshed using thermal-mechanical coupling elements.

9. The method of claim 1, wherein, In step S4, the stress field of the silicon carbide cladding is a first principal stress field.

10. The method of claim 1, wherein, In step S5, calculating the cumulative failure probability of the entire silicon carbide cladding at each time step comprises: for a given time step, for each finite element cell of the silicon carbide cladding, calculating the failure probability of the cell according to its stress, and then numerically integrating the failure probabilities of all cells to obtain the cumulative failure probability.

11. A system for analyzing failure probabilities of a silicon carbide pressurized water reactor fuel rod cladding, the system comprising: The method comprises: a sampling and input module configured to sample the fuel rod power history at different positions of the reactor core and / or the size tolerance of the fuel rod geometric structure parameters, and input the sampling results into the finite element analysis module; a finite element analysis module configured to establish a fuel rod single rod analysis finite element model for performing in-pile irradiation-heat transfer-mechanical coupling behavior analysis to calculate a stress field of the silicon carbide cladding; a failure probability calculation module configured to receive the stress field of the silicon carbide cladding output by the finite element analysis module, and calculate a cumulative failure probability of the entire silicon carbide cladding based on a pre-stored Weibull probability distribution strength model of the silicon carbide cladding material.

12. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that, The computer program is executed by the processor to implement the method of any one of claims 1 to 11.

13. A computer readable storage medium having stored thereon a computer program, characterized in that The computer program is executed by the processor to implement the method of any one of claims 1 to 11.

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