Fuel cladding breakage rate determination method and device and fuel cladding monitoring method and system

Abstract

The invention discloses a fuel cladding breakage rate determination method and device and a fuel cladding monitoring method and system, and relates to the technical field of nuclear industry. The method comprises the following steps: acquiring target neutron kinetic parameters, target power distribution and target burnup of a target reactor core; determining a target fuel parameter and a target thermal hydraulic parameter according to the target neutron kinetic parameter, the target power distribution and the target burnup; and according to the target fuel parameter and the target thermal hydraulic parameter, determining the fuel cladding damage rate in the target reactor core. According to the embodiment of the invention, the method can improve the accuracy of determining the damage rate of the fuel cladding in the large break loss of water accident of the nuclear power plant, and facilitates the selection range of subsequent factory sites with adverse meteorological conditions, inland nuclear power site selection and the like.

Description

Technical Field

[0001] The present application belongs to the field of nuclear industry technology, and specifically relates to a method and device for determining a fuel cladding damage rate, and a method and system for monitoring a fuel cladding. Background Art

[0002] An important part of nuclear power plant safety analysis is to evaluate the environmental impact of various accidents. According to the requirements of national laws and regulations, it is necessary to carry out analysis and evaluation for different accidents at different stages of nuclear power plants.

[0003] For the design basis accident source items, the current safety analysis report of the reactor model has carried out a relatively complete analysis on the progress of the large break loss of coolant accident (LOCA). The analysis results show that all thermal acceptance criteria for the large break loss of coolant accident can be met. In the existing technology, in the process of radioactive consequence evaluation such as the analysis of the damage rate of the fuel cladding in the large break loss of coolant accident, the source item calculation takes into account the damage of 100% of the fuel assemblies in the entire core, and all the radioactive nuclides in the gaps between the fuel cladding are released. This assumption is conservative.

[0004] Although the above practice is conservative, it cannot fully reflect the current technological development. That is, the existing method for determining the fuel cladding damage rate in a large break loss of coolant accident in a nuclear power plant has the problem of low accuracy, and may affect the scope of subsequent site selection such as sites for adverse meteorological conditions and inland nuclear power sites. Summary of the invention

[0005] The technical problem to be solved by the present application is to provide a method and device for determining the damage rate of fuel cladding, and a method and system for monitoring fuel cladding in view of the above-mentioned deficiencies in the prior art. The use of this method can improve the accuracy of determining the damage rate of fuel cladding in large break loss of coolant accidents in nuclear power plants.

[0006] In a first aspect, an embodiment of the present application provides a method for determining a damage rate of a fuel cladding, comprising:

[0007] Obtaining target neutron kinetic parameters, target power distribution and target burnup of the target core;

[0008] Determine target fuel parameters and target thermal hydraulic parameters according to target neutron kinetic parameters, target power distribution and target burnup;

[0009] The fuel cladding damage rate in the target core is determined based on the target fuel parameters and the target thermal-hydraulic parameters.

[0010] In some embodiments of the first aspect, obtaining target neutron kinetic parameters, target power distribution, and target burnup of a target core includes:

[0011] Determining target neutron kinetic parameters, target power distribution and target burnup of the target core through the first type of program;

[0012] The first type of program includes at least one of a SMART program and a SAV program.

[0013] In some embodiments of the first aspect, determining a target fuel parameter and a target thermal hydraulic parameter according to the target neutron kinetic parameter, the target power distribution, and the target burnup includes:

[0014] Determine target fuel parameters according to the target power distribution and the target burnup, the target fuel parameters include fuel parameters under different target power distributions and fuel parameters under different target fuels, the fuel parameters include core heat storage, cladding gap and cladding internal pressure;

[0015] The target thermal-hydraulic parameters are determined according to the target neutron kinetic parameters and the target power distribution.

[0016] In some embodiments of the first aspect, determining a target fuel parameter according to the target power distribution and the target burnup includes:

[0017] Based on the target power distribution and the target burnup, the target fuel parameters are determined by the second type of procedure;

[0018] Among them, the second category of programs includes at least one of the COPERNIC program, the CARO program and the BETHY program.

[0019] In some embodiments of the first aspect, determining a target thermal-hydraulic parameter according to a target neutron kinetic parameter and a target power distribution includes:

[0020] Based on the target neutron kinetic parameters and the target power distribution, the target thermal hydraulic parameters are determined by a third type of procedure;

[0021] Among them, the third category of programs includes any one of the CATHARE-GB program and the RELAP5 program.

[0022] In some embodiments of the first aspect, the target thermal-hydraulic parameter is determined by a third type of procedure, comprising:

[0023] The target information is subjected to sensitivity analysis through the third type of program to obtain the target thermal-hydraulic parameters. The target information includes breach spectrum, average temperature of reactor coolant system, injection box pipeline resistance, injection box temperature system and axial power distribution.

[0024] In some embodiments of the first aspect, determining a fuel cladding damage rate in a target core according to target fuel parameters and target thermal-hydraulic parameters includes:

[0025] According to the target fuel parameters and the target thermal hydraulic parameters, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged is determined;

[0026] The fuel cladding damage rate in the target core is determined based on the total maximum linear power density.

[0027] In some implementations of the first aspect, determining, based on target fuel parameters and target thermal-hydraulic parameters, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged comprises:

[0028] Based on the target fuel parameters and the target thermal hydraulic parameters, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged is determined by the fourth type of program;

[0029] Among them, the fourth category procedure includes at least one of the SAHA procedure and the FRAPTRAN fuel procedure.

[0030] In some embodiments of the first aspect, when the fourth type of program includes a SAHA program, based on the target fuel parameters and the target thermal-hydraulic parameters, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged is determined by the fourth type of program, including:

[0031] The sensitivity analysis of the hot channel enthalpy rise factor was carried out using the SAHA program, and the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core was not damaged was obtained.

[0032] In some embodiments of the first aspect, a sensitivity analysis of the hot channel enthalpy rise factor is performed using a SAHA program to obtain the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged, including:

[0033] The SAHA program is used to simulate the hot rod stress corresponding to different enthalpy rise factors to determine the minimum enthalpy rise factor when the fuel cladding in the target core is not damaged;

[0034] Obtaining the core power, the target axial maximum power peak, the number of fuel assemblies in the target core, the number of fuel rods in the fuel assembly, and the height of the fuel rod active area;

[0035] Substitute the minimum enthalpy rise factor, core power, target axial maximum power peak, number of fuel assemblies, number of fuel rods and height of the active area of ​​the fuel rods into formula (1) for calculation, and obtain the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged;

[0036] Formula (1) includes:

[0037]

[0038] Among them, LPD max represents the maximum linear power density; P represents the core power; P r represents the minimum enthalpy rise factor; f z,max Indicates the target axial maximum power peak; N a Indicates the number of fuel assemblies; N r represents the number of fuel rods; h represents the height of the active area of ​​the fuel rod.

[0039] In some embodiments of the first aspect, determining the fuel cladding damage rate in the target core according to the total maximum linear power density includes:

[0040] Based on the full maximum linear power density, the fuel cladding damage rate in the target core is determined by the first type of procedure;

[0041] The first type of program includes at least one of a SMART program and a SAV program.

[0042] In some embodiments of the first aspect, when the first type of program includes a SMART program, determining the damage rate of fuel cladding in the target core by the first type of program includes:

[0043] Based on all maximum linear power densities, the target number of maximum linear power densities with a value greater than or equal to a preset power density is counted through the SMART program, and the target number is taken as the number of fuel rods with damaged cladding;

[0044] The number of fuel rods with damaged cladding and the total number of fuel rods in the target core are substituted into formula (2) through the SMART program to calculate the fuel cladding damage rate in the target core;

[0045] Among them, formula (2) includes:

[0046]

[0047] Where FR is the fuel cladding damage rate; N over Indicates the number of fuel rods with damaged cladding; N total Indicates the total number of fuel rods.

[0048] In some embodiments of the first aspect, the target neutron kinetic parameter includes at least one of a moderator density coefficient, a Doppler coefficient, a fast neutron lifetime, a thermal channel factor, and a thermal power peak factor;

[0049] The target power distribution includes normalized axial power distribution at different cycles and lifetimes;

[0050] The target thermal-hydraulic parameters include at least one of system pressure, core power, heat transfer coefficient between cladding and coolant, coolant temperature and maximum fuel cladding temperature.

[0051] Based on the same inventive concept, in a second aspect, the embodiment of the present application further provides a fuel cladding monitoring method, comprising:

[0052] Determine the fuel cladding damage rate in the target core corresponding to different target burnups according to the method for determining the fuel cladding damage rate of any one of the first aspects;

[0053] According to each target burnup and its corresponding target fuel cladding damage rate in the core, the relationship between the burnup and the fuel cladding damage rate is determined to determine the maximum fuel cladding damage rate during the entire life cycle.

[0054] Based on the same inventive concept, in a third aspect, an embodiment of the present application further provides a fuel cladding damage rate determination device, comprising:

[0055] A first acquisition module is used to acquire target neutron kinetic parameters, target power distribution and target burnup of a target core;

[0056] A first determination module, connected to the first acquisition module, is used to determine target fuel parameters and target thermal hydraulic parameters according to target neutron kinetic parameters, target power distribution and target burnup;

[0057] The second determination module is connected to the first determination module and is used to determine the fuel cladding damage rate in the target core according to the target fuel parameters and the target thermal hydraulic parameters.

[0058] In some implementations of the third aspect, the first acquisition module is specifically configured to:

[0059] Determining target neutron kinetic parameters, target power distribution and target burnup of the target core through the first type of program;

[0060] The first type of program includes at least one of a SMART program and a SAV program.

[0061] In some implementations of the third aspect, the first determining module is specifically configured to:

[0062] Determine target fuel parameters according to the target power distribution and the target burnup, the target fuel parameters include fuel parameters under different target power distributions and fuel parameters under different target fuels, the fuel parameters include core heat storage, cladding gap and cladding internal pressure;

[0063] The target thermal-hydraulic parameters are determined according to the target neutron kinetic parameters and the target power distribution.

[0064] In some implementations of the third aspect, the second determining module is specifically configured to:

[0065] According to the target fuel parameters and the target thermal hydraulic parameters, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged is determined;

[0066] The fuel cladding damage rate in the target core is determined based on the total maximum linear power density.

[0067] Based on the same inventive concept, in a fourth aspect, the embodiment of the present application further provides a fuel cladding monitoring system, comprising:

[0068] The fuel cladding damage rate determination device according to any one of the third aspects is used to determine the fuel cladding damage rates in the target cores corresponding to different target burnups;

[0069] The fuel cladding monitoring device is connected to the fuel cladding damage rate determination device and is used to determine the changing relationship between the burnup and the fuel cladding damage rate based on each target burnup and its corresponding target fuel cladding damage rate in the core, so as to determine the maximum fuel cladding damage rate during the entire life cycle.

[0070] According to the fuel cladding damage rate determination method and device, fuel cladding monitoring method and system provided in the embodiment of the present application, the target neutron kinetic parameters, target power distribution and target burnup of the target core are first obtained; then the target fuel parameters and target thermal hydraulic parameters are determined according to the target neutron kinetic parameters, target power distribution and target burnup of the target core; and then the fuel cladding damage rate in the target core is determined according to the target fuel parameters and target thermal hydraulic parameters. That is to say, in the embodiment of the present application, the fuel cladding damage rate determination method combines the target thermal hydraulic parameters, selects the worst working conditions, and determines the fuel cladding damage rate in the target core based on this. When calculating the source term, it is not necessary to assume that 100% of the fuel assemblies in the entire core are damaged, which increases the margin for the selection of the accident source term, thereby improving the accuracy of determining the fuel cladding damage rate in the large break loss of coolant accident of the nuclear power plant, and is conducive to the subsequent selection of sites such as unfavorable meteorological conditions and inland nuclear power sites. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 A schematic diagram showing a flow chart of a method for determining a damage rate of a fuel cladding provided in an embodiment of the present application;

[0072] Figure 2 A schematic diagram showing the relationship between time and heat rod stress under four enthalpy rise factors provided in the embodiments of the present application;

[0073] Figure 3 A schematic diagram showing a flow chart of a fuel cladding monitoring method provided in an embodiment of the present application;

[0074] Figure 4 Another schematic diagram showing a flow chart of a fuel cladding monitoring method provided in an embodiment of the present application;

[0075] Figure 5 A schematic diagram showing a structure of a fuel cladding damage rate determination device provided in an embodiment of the present application;

[0076] Figure 6 A structural schematic diagram of a fuel cladding monitoring system provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0077] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is further described in detail below with reference to the accompanying drawings and embodiments.

[0078] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application and are not configured to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0079] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0080] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0081] As described in the background technology, the current practice has not yet combined the specific accident analysis results to carry out the selection and calculation of source items. Although this practice is conservative, it cannot fully reflect the current technological development, that is, the existing method for determining the damage rate of fuel cladding in a large break loss of coolant accident in a nuclear power plant has the problem of low accuracy, and may affect the subsequent selection of sites such as unfavorable meteorological conditions and inland nuclear power sites.

[0082] Example 1

[0083] Figure 1 A schematic flow chart of a method for determining a fuel cladding damage rate provided in an embodiment of the present application is shown.

[0084] The fuel cladding damage rate determination method provided in the embodiment of the present application can be applied to a large-break loss of coolant accident in a nuclear power plant, and the nuclear power plant may include a pressurized water reactor nuclear power plant. The fuel cladding damage rate determination method can be executed by an electronic device and a fuel cladding damage rate determination device. The following is an example of the fuel cladding damage rate determination method being executed by an electronic device.

[0085] like Figure 1 As shown, the method for determining the damage rate of fuel cladding provided in the embodiment of the present application may include steps S110 to S130.

[0086] S110, obtaining target neutron kinetic parameters, target power distribution, and target burnup of the target core.

[0087] S120. Determine target fuel parameters and target thermal hydraulic parameters according to target neutron kinetic parameters, target power distribution, and target burnup.

[0088] S130. Determine the damage rate of the fuel cladding in the target core according to the target fuel parameters and the target thermal-hydraulic parameters.

[0089] According to the fuel cladding damage rate determination method and device, fuel cladding monitoring method and system provided in the embodiment of the present application, the target neutron kinetic parameters, target power distribution and target burnup of the target core are first obtained; then the target fuel parameters and target thermal hydraulic parameters are determined according to the target neutron kinetic parameters, target power distribution and target burnup of the target core; and then the fuel cladding damage rate in the target core is determined according to the target fuel parameters and target thermal hydraulic parameters. That is to say, in the embodiment of the present application, the fuel cladding damage rate determination method combines the target thermal hydraulic parameters, selects the worst working conditions, and determines the fuel cladding damage rate in the target core based on this. When calculating the source term, it is not necessary to assume that 100% of the fuel assemblies in the entire core are damaged, which increases the margin for the selection of the accident source term, thereby improving the accuracy of determining the fuel cladding damage rate in the large break loss of coolant accident of the nuclear power plant, and is conducive to the subsequent selection of sites such as unfavorable meteorological conditions and inland nuclear power sites.

[0090] In step S110 , the target core may be any core for which the fuel cladding damage rate needs to be determined.

[0091] The target neutron kinetic parameter includes at least one of a moderator density coefficient, a Doppler coefficient, a fast neutron lifetime, a thermal channel factor, and a thermal power peak factor.

[0092] Among them, the moderator density coefficient can be the coefficient of the influence of the density change of the moderator (such as light water or heavy water) on the reactor reactivity; the Doppler coefficient can be the change in neutron resonance absorption caused by the change in fuel temperature; the fast neutron lifetime can be the time or period of existence of fast neutrons; the hot channel factor can be the ratio of the average specific enthalpy rise or axial average heat flux density of the reactor coolant in the hot channel to the corresponding average specific enthalpy rise or average heat flux density of the core after considering various unfavorable factors of nuclear and engineering; the thermal power peak factor can be used to indicate the deviation of parameters such as the heat flux density, coolant flow rate, coolant enthalpy rise and temperature of the fuel elements in the target core from the nominal values.

[0093] As an example, the target neutron kinetic parameter may include a moderator density coefficient.

[0094] As another example, target neutron kinetic parameters may include the Doppler coefficient and the fast neutron lifetime.

[0095] As yet another example, target neutron kinetic parameters may include fast neutron lifetime, thermal channel factor, and thermal power peak factor.

[0096] As yet another example, target neutron kinetic parameters may include moderator density coefficient, Doppler coefficient, fast neutron lifetime, and thermal channel factor.

[0097] As yet another example, target neutron kinetic parameters may include moderator density coefficient, Doppler coefficient, fast neutron lifetime, thermal channel factor, and thermal power peak factor.

[0098] The target power distribution includes the normalized axial power distribution at different cycles and lifetimes.

[0099] The target burnup may include the usage of nuclear fuel in the target core in the nuclear reactor.

[0100] In some embodiments, obtaining target neutron kinetic parameters, target power distribution, and target burnup of a target core may include:

[0101] Determining target neutron kinetic parameters, target power distribution and target burnup of the target core through the first type of program;

[0102] The first type of program includes at least one of a SMART program and a SAV program.

[0103] Exemplarily, the SMART program may be the Korean SMART integrated modular advanced reactor, which is an integrated advanced pressurized water reactor independently developed by the Korea Atomic Energy Research Institute.

[0104] Exemplarily, the SAV program may be a safety analysis verification program, whose main function is to verify the accuracy and completeness of the safety analysis report of the nuclear facility, to ensure that the design and operation of the nuclear facility meet safety standards, and thus to ensure the safe operation of the nuclear facility.

[0105] As an example, the first category of programs includes SMART programs.

[0106] As another example, the first category of programs includes SAV programs.

[0107] As yet another example, the first category of programs includes SMART programs and SAV programs.

[0108] For example, the SMART program can calculate neutron dynamic parameters such as moderator density coefficient, Doppler coefficient, fast neutron lifetime, thermal channel factor, thermal power peak factor, and parameters such as normalized axial power distribution and burnup for different cycles and lifetimes.

[0109] In other embodiments, the target neutron kinetic parameters, target power distribution, and target burnup of the target core may be pre-stored in the electronic device for subsequent direct retrieval.

[0110] In step S120, after obtaining the target neutron kinetic parameters, target power distribution and target burnup of the target core, the electronic equipment may also determine the target fuel parameters and target thermal-hydraulic parameters according to the target neutron kinetic parameters, target power distribution and target burnup.

[0111] The target thermal-hydraulic parameters include at least one of system pressure, core power, heat transfer coefficient (HTC) between cladding and coolant, coolant temperature and maximum fuel cladding temperature (PCT).

[0112] Among them, the system pressure may include the pressure borne by key components such as the cooling system and pressure vessels of the nuclear power plant; the core power may be the heat generated by the nuclear reaction in the core area of ​​the nuclear reactor, and may be the ratio of the core heat release power to the core volume; the heat transfer coefficient between the cladding and the coolant may be the amount of heat that can be transferred per degree of temperature difference between the wall and the fluid per unit surface area per unit time; the coolant temperature may be the temperature of the coolant used to cool the reactor core or other heat sources; the maximum fuel cladding temperature may be the maximum temperature that the fuel cladding can withstand in a nuclear reactor.

[0113] As an example, the target thermal-hydraulic parameter may include system pressure.

[0114] As another example, target thermal-hydraulic parameters may include core power, and heat transfer coefficient between cladding and coolant.

[0115] As yet another example, the target thermal-hydraulic parameters may include a heat transfer coefficient between the cladding and the coolant, a coolant temperature, and a maximum fuel cladding temperature.

[0116] As yet another example, the target thermal-hydraulic parameters may include core power, heat transfer coefficient between cladding and coolant, coolant temperature, and maximum fuel cladding temperature.

[0117] As yet another example, target thermal-hydraulic parameters may include system pressure, core power, heat transfer coefficient between cladding and coolant, coolant temperature, and maximum fuel cladding temperature.

[0118] In some embodiments, determining target fuel parameters and target thermal hydraulic parameters according to target neutron kinetic parameters, target power distribution, and target burnup may include:

[0119] Determine target fuel parameters according to the target power distribution and the target burnup, the target fuel parameters include fuel parameters under different target power distributions and fuel parameters under different target fuels, the fuel parameters include core heat storage, cladding gap and cladding internal pressure;

[0120] The target thermal-hydraulic parameters are determined according to the target neutron kinetic parameters and the target power distribution.

[0121] Exemplarily, the core heat storage may be the heat generated by the target core; the cladding gap may include the annular gap between the fuel pellets and the cladding; and the cladding internal pressure may include the pressure borne by the inside of the cladding.

[0122] It should be noted that in the embodiments of the present application, the fuel parameters may also include other parameters besides core heat storage, cladding gap and cladding internal pressure, which are not limited here.

[0123] In some embodiments, determining the target fuel parameter according to the target power distribution and the target burnup may include:

[0124] Based on the target power distribution and the target burnup, the target fuel parameters are determined by the second type of procedure;

[0125] Among them, the second category of programs includes at least one of the COPERNIC program, the CARO program and the BETHY program.

[0126] Exemplarily, the COPERNIC program may be a program for fuel rod performance analysis; the CARO program may be an applied research tool for radiation field monitoring and corrosion product control measures; and the BETHY program may be a computer program for simulating the nuclear fuel cycle in a nuclear reactor.

[0127] As an example, programs of the second category include the COPERNIC program.

[0128] As another example, the second category of programs includes the CARO program and the BETHY program.

[0129] As yet another example, the second category of programs includes the COPERNIC program, the CARO program, and the BETHY program.

[0130] In some embodiments, determining target thermal hydraulic parameters according to target neutron kinetic parameters and target power distribution may include:

[0131] Based on the target neutron kinetic parameters and the target power distribution, the target thermal hydraulic parameters are determined by a third type of procedure;

[0132] Among them, the third category of programs includes any one of the CATHARE-GB program and the RELAP5 program.

[0133] For example, the CATHARE-GB program may be a program for safety analysis of nuclear power plants; the RELAP5 program may be a program for transient analysis of reactor system accidents.

[0134] As an example, the third category of programs includes the CATHARE-GB program.

[0135] As another example, the third category of programs includes the RELAP5 program.

[0136] As yet another example, the third category of programs includes the CATHARE-GB program and the RELAP5 program.

[0137] In some examples, determining the target thermal-hydraulic parameters by the third type of procedure may include:

[0138] The target information including breach spectrum, reactor coolant system (RCS) average temperature, injection box pipeline resistance, injection box temperature system and axial power distribution are analyzed by sensitivity analysis of the target information through the third type of program to obtain the target thermal hydraulic parameters.

[0139] Exemplarily, the breach spectrum may be a graph that describes the fission gas release characteristics produced by nuclear fuel at different burnup levels; the average temperature of the reactor coolant system refers to the average temperature of the coolant used to cool the nuclear fuel in the nuclear reactor during its flow in the system; the injection tank pipeline resistance may be the fluid resistance of the pipeline between the injection tank (usually refers to the storage tank of the emergency cooling system) and the reactor cooling system in a nuclear power plant; the injection tank temperature system may be a system in a nuclear power plant used to monitor and control the coolant temperature in the injection tank; the axial power distribution may be the power distribution along the axial direction of the reactor core (from top to bottom) in a nuclear reactor.

[0140] In step S130, after determining the target fuel parameters and target thermal-hydraulic parameters according to the target neutron kinetic parameters, target power distribution and target burnup, the electronic equipment can also determine the fuel cladding damage rate in the target core according to the target fuel parameters and target thermal-hydraulic parameters.

[0141] For example, the fuel cladding damage rate may be the proportion of fuel cladding damage during the operation of a nuclear power plant.

[0142] In some embodiments, determining the target fuel cladding damage rate in the core according to the target fuel parameters and the target thermal hydraulic parameters may include:

[0143] According to the target fuel parameters and the target thermal hydraulic parameters, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged is determined;

[0144] The fuel cladding damage rate in the target core is determined based on the total maximum linear power density.

[0145] For example, linear power density may be used to represent the power produced per unit length of a reactor fuel rod or other reactor assembly.

[0146] It should be noted that the target core may include multiple fuel rods. When the fuel cladding in the target core is not damaged, each fuel rod may correspond to multiple linear power densities.

[0147] In some embodiments, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged is determined according to the target fuel parameters and the target thermal-hydraulic parameters, including:

[0148] Based on the target fuel parameters and the target thermal hydraulic parameters, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged is determined by the fourth type of program;

[0149] Among them, the fourth category procedure includes at least one of the SAHA procedure and the FRAPTRAN fuel procedure.

[0150] Exemplarily, the SAHA program may be a program related to the safety and reliability of nuclear power plant operation. Specifically, it is a system implemented by Electricite de France (EDF) to ensure the high availability and reliability of nuclear power plant systems. The FRAPTRAN fuel program is a transient fuel performance code that can be used to simulate and predict the behavior of nuclear fuel in a reactor, especially under high burnup and accident conditions. The FRAPTRAN fuel program can be used to calculate fuel cladding damage under LOCA accidents.

[0151] Exemplarily, the SAHA program may be the SAHA program of the CATHARE program package.

[0152] As an example, the fourth category of programs includes the SAHA program.

[0153] As another example, the fourth category of programs includes the FRAPTRAN fuel program.

[0154] As yet another example, the fourth category of programs includes the SAHA program and the FRAPTRAN fuel program.

[0155] In some embodiments, when the fourth type of program includes a SAHA program, based on the target fuel parameters and the target thermal hydraulic parameters, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged is determined by the fourth type of program, including:

[0156] The sensitivity analysis of the hot channel enthalpy rise factor was carried out using the SAHA program, and the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core was not damaged was obtained.

[0157] Exemplarily, the hot channel enthalpy rise factor may be the ratio of the average specific enthalpy rise of the reactor coolant in the hot channel to the corresponding average specific enthalpy rise of the core.

[0158] In some examples, the sensitivity analysis of the hot channel enthalpy rise factor is performed through the SAHA program to obtain the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged, including:

[0159] The SAHA program is used to simulate the hot rod stress corresponding to different enthalpy rise factors to determine the minimum enthalpy rise factor when the fuel cladding in the target core is not damaged;

[0160] Obtaining the core power, the target axial maximum power peak, the number of fuel assemblies in the target core, the number of fuel rods in the fuel assembly, and the height of the fuel rod active area;

[0161] Substitute the minimum enthalpy rise factor, core power, target axial maximum power peak, number of fuel assemblies, number of fuel rods and height of the active area of ​​the fuel rods into formula (1) for calculation, and obtain the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged;

[0162] Formula (1) includes:

[0163]

[0164] Among them, LPD max represents the maximum linear power density; P represents the core power; P r represents the minimum enthalpy rise factor; f z,max Indicates the target axial maximum power peak; N a Indicates the number of fuel assemblies; N r represents the number of fuel rods; h represents the height of the active area of ​​the fuel rod.

[0165] Exemplarily, the enthalpy rise factor can be used to describe the thermal performance of fuel rods in a nuclear reactor, which indicates the degree of temperature rise of the fuel in the fuel rod under unit nuclear reactor power; the thermal rod stress may be the various mechanical stresses to which the fuel rod is subjected when operating in the nuclear reactor; the target axial maximum power peak may be the maximum value of the power distribution along the axial direction in the reactor; the fuel assembly may be a whole group of fuel elements assembled together; the fuel rod may be an assembly in a nuclear reactor used to store and provide nuclear fuel; the fuel rod active area height may be the effective length of the fuel part of the fuel rod in the nuclear reactor within the core of the nuclear reactor.

[0166] In some examples, the core power may be 3.05E6 kW, the number of fuel assemblies may be 177, the number of fuel rods may be 264, and the height of the fuel rod active region may be 3.6576 m.

[0167] Exemplarily, the electronic device may pre-store the core power, the target axial maximum power peak, the target number of fuel assemblies in the core, the number of fuel rods in the fuel assembly and the height of the fuel rod active area for subsequent direct retrieval.

[0168] For example, taking the beginning of the life cycle as an example, after determining the most extreme calculation conditions (i.e., the conditions where the target thermal hydraulic parameters are closest to the limit, generally referring to whether the maximum fuel cladding temperature is over-temperature) and the initial conditions, a sensitivity analysis of the heat channel enthalpy rise factor is performed in the CATHARE-GB program (i.e., the SAHA program of the CATHARE program package), and the maximum power critical linear power density (i.e., the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged) without damage to the fuel rod cladding is obtained by analysis. F is set respectively. △H =1.6, F △H =1.4, F △H =1.3, F △H =1.2 four enthalpy rise factors. The transient processes of the four enthalpy rise factor sensitivity conditions are the same, and the fuel rod response results (i.e., hot rod stress) simulated by the SAHA program are different. Among them, the initial conditions include at least one of the core power, primary circuit temperature, pressure, flow, core bypass flow, and pressurizer water level.

[0169] Figure 2 A schematic diagram showing the relationship between time and hot rod stress under four enthalpy rise factors provided in the embodiments of the present application is shown, wherein: Figure 2 The horizontal axes of the four sub-graphs are all time, and the unit is s; Figure 2 The vertical coordinates of the four sub-graphs are all hot rod stress, and its unit is Pa; the solid line represents the hot rod damage stress, referred to as damage stress; the dotted line represents the hot rod actual stress, referred to as actual stress; Figure 2 The sub-graph in the upper left corner represents F △H =1.6 Relationship between time and hot rod stress; Figure 2 The sub-graph in the upper right corner represents F △H =1.4 Relationship between time and hot rod stress; Figure 2 The sub-graph in the lower left corner represents F △H =1.3 The relationship between time and hot rod stress; Figure 2 The sub-graph in the lower right corner represents F △H =1.2The relationship between time and hot rod stress.

[0170] from Figure 2 It can be seen from the area 1 of the upper left sub-image, the area 2 of the upper right sub-image, and the area 3 of the lower left sub-image that F △H =1.6, F △H =1.4, F △H =1.3, the actual stress of the hot rod reaches the failure stress of the fuel rod, and the fuel cladding is damaged; Figure 2 Area 4 in the lower right sub-figure shows that F △H= 1.2, the actual stress of the hot rod did not reach the damage stress of the fuel rod, indicating that the fuel cladding was not damaged. Therefore, the minimum enthalpy rise factor without fuel cladding damage can be obtained as F △H =1.2.

[0171] In some embodiments, determining the damage rate of the fuel cladding in the target core according to the total maximum linear power density may include:

[0172] Based on the full maximum linear power density, the fuel cladding damage rate in the target core is determined by the first type of procedure;

[0173] The first type of program includes at least one of a SMART program and a SAV program.

[0174] In some embodiments, when the first type of procedure includes a SMART procedure, determining the fuel cladding damage rate in the target core by the first type of procedure may include:

[0175] Based on all maximum linear power densities, the target number of maximum linear power densities with a value greater than or equal to a preset power density is counted through the SMART program, and the target number is taken as the number of fuel rods with damaged cladding;

[0176] The number of fuel rods with damaged cladding and the total number of fuel rods in the target core are substituted into formula (2) through the SMART program to calculate the fuel cladding damage rate in the target core;

[0177] Among them, formula (2) includes:

[0178]

[0179] Where FR is the fuel cladding damage rate; N over Indicates the number of fuel rods with damaged cladding; N total Indicates the total number of fuel rods.

[0180] Exemplarily, the total number of fuel rods in the target core is pre-stored in the electronic device for subsequent direct retrieval, that is, the total number of fuel rods in the target core is known.

[0181] The preset power density can be set according to actual conditions and is not limited here. For example, the preset power density can be 31.7 kw / m.

[0182] It should be noted that the target number of fuel rods (i.e., the number of fuel rods with damaged cladding) may be the number of fuel rods corresponding to the maximum linear power density whose value is greater than or equal to the preset power density, that is, the number of maximum linear power density whose value is greater than or equal to the preset power density.

[0183] Exemplarily, the number of fuel rods with damaged cladding is 4, and the total number of fuel rods is 264, then the fuel cladding damage rate FR=0.76%.

[0184] It should be noted that, in the embodiment of the present application, the above-mentioned method for determining the fuel cladding damage rate may be a burnup sensitivity analysis, the purpose of which is to determine the maximum fuel cladding damage rate during the entire life cycle of the core, so as to provide more margin for the source term calculation.

[0185] Based on the same inventive concept, an embodiment of the present application further provides a fuel cladding monitoring method. The fuel cladding monitoring method provided by the embodiment of the present application is introduced below in conjunction with the accompanying drawings.

[0186] Example 2

[0187] Figure 3 A schematic flow chart of a fuel cladding monitoring method provided in an embodiment of the present application is shown.

[0188] The fuel cladding monitoring method provided in the embodiment of the present application can be executed by an electronic device and a fuel cladding monitoring system, etc.

[0189] The fuel cladding monitoring method provided in the embodiment of the present application may include steps S310 to S320.

[0190] S310. According to the method for determining the damage rate of fuel cladding of any one of Embodiment 1, the damage rates of fuel cladding in the target core corresponding to different target burnups are determined.

[0191] S320. According to each target burnup and its corresponding target fuel cladding damage rate in the core, determine the changing relationship between the burnup and the fuel cladding damage rate to determine the maximum fuel cladding damage rate during the entire life cycle.

[0192] According to the fuel cladding monitoring method provided in the embodiments of the present application, the fuel cladding damage rate in the target core corresponding to different target burnups is determined through the fuel cladding damage rate determination method of any one of Embodiment 1, which can improve the accuracy of determining the fuel cladding damage rate in a large break loss of coolant accident in a nuclear power plant. Furthermore, based on each target burnup and its corresponding fuel cladding damage rate in the target core, the changing relationship between the burnup and the fuel cladding damage rate can be determined to determine the maximum fuel cladding damage rate over the entire life cycle, thereby providing an accurate cladding damage rate for source term calculation.

[0193] It can be understood that in the embodiment of the present application, the changes in burnup and fuel cladding damage rate can also be used to predict the fuel cladding damage rate.

[0194] It should be noted that steps S110 to S130 in Example 1 may be repeated for different target burnups to calculate the relationship between the fuel cladding damage rate and the burnup under different target burnups. Each target burnup corresponds to a target power distribution.

[0195] In order to better understand the fuel cladding monitoring method provided in the embodiment of the present application, a specific embodiment is described below.

[0196] like Figure 4 As shown, the fuel cladding monitoring method provided in the embodiment of the present application may include steps S410 to S470.

[0197] S410 , the physical program SMART (ie, the SMART program) calculates the power distribution (ie, the target power distribution).

[0198] That is to say, the SMART program calculates neutron dynamic parameters such as moderator density coefficient, Doppler coefficient, fast neutron lifetime, thermal channel factor, thermal power peak factor, and parameters such as normalized axial power distribution and burnup (i.e. target burnup) of different cycles and lifetimes.

[0199] S420. The fuel program COPERNIC (ie, COPERNIC program) calculates fuel parameters (ie, target fuel parameters).

[0200] That is to say, using the power distribution (i.e., target power distribution) and fuel consumption parameters of step S410, the COPERNIC program calculates fuel parameters (i.e., target fuel parameters) such as core heat storage, cladding gap, and cladding internal pressure under different fuel consumption and various power distribution conditions.

[0201] S430, the thermal program CATHARE-GB determines the most extreme operating condition (i.e. the operating condition where the target thermal hydraulic parameter is closest to the limit value, generally refers to whether the maximum fuel cladding temperature exceeds the temperature).

[0202] That is to say, using the neutron kinetic parameters and power distribution of step S410, the CATHARE-GB program is used to perform a relatively comprehensive calculation of the large LOCA accident. Extensive calculation and analysis are performed on various parameters that affect the large LOCA accident. Through the sensitivity analysis of the breach spectrum, the average RCS temperature, the injection box pipeline resistance and the injection box temperature system sensitivity analysis, and the axial power distribution sensitivity analysis, the calculation conditions that affect the cladding damage most severely due to the large LOCA accident are found (i.e., the conditions where the target thermal hydraulic parameters are closest to the limit, generally referring to whether the maximum fuel cladding temperature is over-temperature).

[0203] S440. The SAHA program determines the maximum linear power density without damage to the fuel cladding (ie, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged).

[0204] That is, the fuel parameters of step S420 and the thermal hydraulic parameters of step S430 are used to calculate the maximum linear power density of the fuel rod when the fuel cladding is not damaged using the SAHA program of the CATHARE program package.

[0205] Taking the beginning of the service life as an example, after determining the most extreme calculation conditions (i.e. the conditions where the target thermal-hydraulic parameters are closest to the limit, generally referring to whether the maximum fuel cladding temperature is over-temperature) and initial conditions, a sensitivity analysis of the heat channel enthalpy rise factor is performed in the CATHARE-GB program (i.e. the SAHA program of the CATHARE program package), and the maximum power critical linear power density (i.e. the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged) without damage to the fuel rod cladding is obtained. F is set respectively. △H =1.6, F △H =1.4, F △H =1.3, F △H =1.2 four enthalpy rise factors. The transient processes of the four enthalpy rise factor sensitivity conditions are the same, and the fuel rod response results (i.e., hot rod stress) simulated by the SAHA program are different. Among them, the initial conditions include at least one of the core power, primary circuit temperature, pressure, flow, core bypass flow, and pressurizer water level.

[0206] from Figure 2 It can be seen from the area 1 of the upper left sub-image, the area 2 of the upper right sub-image, and the area 3 of the lower left sub-image that F △H =1.6, F △H =1.4, F △H =1.3, the actual stress of the hot rod reaches the failure stress of the fuel rod, and the fuel cladding is damaged; Figure 2 Area 4 in the lower right sub-figure shows that F △H = 1.2, the actual stress of the hot rod did not reach the damage stress of the fuel rod, indicating that the fuel cladding was not damaged. Therefore, the minimum enthalpy rise factor without fuel cladding damage can be obtained as F △H =1.2.

[0207] The maximum linear power density of the fuel rod can be obtained by formula (1):

[0208]

[0209] in:

[0210] LPD max is the maximum linear power density of the fuel rod;

[0211] P is the core power, in kW, and its value is 3.05E6;

[0212] Pr is the minimum enthalpy rise factor (also known as F) without cladding damage. △H =1.2);

[0213] f z,max is the maximum axial power peak of the assembly where the rod is located;

[0214] Na is the number of fuel assemblies in the core, in pieces, with a value of 177;

[0215] Nr is the number of fuel rods in the fuel assembly, in pieces, and the value is 264;

[0216] h is the height of the active area of ​​the fuel rod, in meters, and its value is 3.6576.

[0217] By using formula (1), the maximum linear power density of each fuel rod in the core can be obtained.

[0218] S450, the physical program SMART calculates the fuel cladding damage rate.

[0219] That is to say, by using the SMART program to collect statistics on all fuel rods with a maximum linear power density exceeding 31.7 kW / m, the damage rate of the fuel rod cladding at the beginning of the life cycle can be obtained. The formula (2) for calculating the damage rate of the cladding is:

[0220]

[0221] in:

[0222] FR is the fuel rod cladding damage rate;

[0223] N over The number of fuel rods with a maximum linear power density exceeding 31.7 kW / m (i.e. the number of fuel rods with damaged cladding);

[0224] N total is the total number of fuel rods.

[0225] S460: Determine whether to perform fuel consumption sensitivity analysis (ie, whether to execute steps S410 to S460).

[0226] If the judgment result of S460 is no, execute step S470.

[0227] If the judgment result of S460 is yes, step S410 is executed.

[0228] S470. Determine the relationship between the fuel cladding damage rate and the fuel consumption (i.e., the relationship between the fuel consumption and the fuel cladding damage rate).

[0229] That is to say, by analyzing different burnup depths (i.e., target burnup), we can obtain the relationship between the fuel cladding damage rate and burnup, and ultimately determine the maximum fuel cladding damage rate over the entire life cycle, as well as the fuel cladding damage rate that can be used for prediction.

[0230] Based on the same inventive concept, an embodiment of the present application further provides a fuel cladding damage rate determination device. The fuel cladding damage rate determination device provided in the embodiment of the present application is introduced below in conjunction with the accompanying drawings.

[0231] Example 3

[0232] like Figure 5 As shown, the fuel cladding damage rate determination device 500 provided in the embodiment of the present application may include a first acquisition module 510 , a first determination module 520 and a second determination module 530 .

[0233] The first acquisition module 510 is used to acquire target neutron kinetic parameters, target power distribution and target burnup of the target core;

[0234] A first determination module 520, connected to the first acquisition module 510, for determining target fuel parameters and target thermal hydraulic parameters according to target neutron kinetic parameters, target power distribution and target burnup;

[0235] The second determination module 530 is connected to the first determination module 520 and is used to determine the fuel cladding damage rate in the target core according to the target fuel parameters and the target thermal hydraulic parameters.

[0236] According to the fuel cladding damage rate determination device provided in the embodiment of the present application, the target neutron kinetic parameters, target power distribution and target burnup of the target core are first obtained; then the target fuel parameters and target thermal hydraulic parameters are determined according to the target neutron kinetic parameters, target power distribution and target burnup of the target core; and then the fuel cladding damage rate in the target core is determined according to the target fuel parameters and target thermal hydraulic parameters. That is to say, in the embodiment of the present application, the fuel cladding damage rate determination method combines the target thermal hydraulic parameters, selects the worst working conditions, and determines the fuel cladding damage rate in the target core based on this. When calculating the source term, it is not necessary to assume that 100% of the fuel assemblies in the entire core are damaged, which increases the margin for the selection of the accident source term, thereby improving the accuracy of determining the fuel cladding damage rate of the large break loss of coolant accident in the nuclear power plant, and is conducive to the subsequent selection of sites such as unfavorable meteorological conditions and inland nuclear power sites.

[0237] In some implementations, the first acquisition module 510 is specifically configured to:

[0238] Determining target neutron kinetic parameters, target power distribution and target burnup of the target core through the first type of program;

[0239] The first type of program includes at least one of a SMART program and a SAV program.

[0240] In some implementations, the first determining module 520 is specifically configured to:

[0241] Determine target fuel parameters according to the target power distribution and the target burnup, the target fuel parameters include fuel parameters under different target power distributions and fuel parameters under different target fuels, the fuel parameters include core heat storage, cladding gap and cladding internal pressure;

[0242] The target thermal-hydraulic parameters are determined according to the target neutron kinetic parameters and the target power distribution.

[0243] In some implementations, the first determining module 520 is specifically configured to:

[0244] Based on the target power distribution and the target burnup, the target fuel parameters are determined by the second type of procedure;

[0245] Among them, the second category of programs includes at least one of the COPERNIC program, the CARO program and the BETHY program.

[0246] In some implementations, the first determining module 520 is specifically configured to:

[0247] Based on the target neutron kinetic parameters and the target power distribution, the target thermal hydraulic parameters are determined by a third type of procedure;

[0248] Among them, the third category of programs includes any one of the CATHARE-GB program and the RELAP5 program.

[0249] In some implementations, the first determining module 520 is specifically configured to:

[0250] The target information is subjected to sensitivity analysis through the third type of program to obtain the target thermal-hydraulic parameters. The target information includes breach spectrum, average temperature of reactor coolant system, injection box pipeline resistance, injection box temperature system and axial power distribution.

[0251] In some implementations, the second determining module 530 is specifically configured to:

[0252] According to the target fuel parameters and the target thermal hydraulic parameters, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged is determined;

[0253] The fuel cladding damage rate in the target core is determined based on the total maximum linear power density.

[0254] In some implementations, the second determining module 530 is specifically configured to:

[0255] Based on the target fuel parameters and the target thermal hydraulic parameters, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged is determined by the fourth type of program;

[0256] Among them, the fourth category procedure includes at least one of the SAHA procedure and the FRAPTRAN fuel procedure.

[0257] In some implementations, when the fourth type of program includes the SAHA program, the second determination module 530 is specifically configured to:

[0258] The sensitivity analysis of the hot channel enthalpy rise factor was carried out using the SAHA program, and the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core was not damaged was obtained.

[0259] In some implementations, the second determining module 530 is specifically configured to:

[0260] The SAHA program is used to simulate the hot rod stress corresponding to different enthalpy rise factors to determine the minimum enthalpy rise factor when the fuel cladding in the target core is not damaged;

[0261] Obtaining the core power, the target axial maximum power peak, the number of fuel assemblies in the target core, the number of fuel rods in the fuel assembly, and the height of the fuel rod active area;

[0262] Substitute the minimum enthalpy rise factor, core power, target axial maximum power peak, number of fuel assemblies, number of fuel rods and height of the active area of ​​the fuel rods into formula (1) for calculation, and obtain the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged;

[0263] Formula (1) includes:

[0264]

[0265] Among them, LPD max represents the maximum linear power density; P represents the core power; P r represents the minimum enthalpy rise factor; f z,max Indicates the target axial maximum power peak; N a Indicates the number of fuel assemblies; N r represents the number of fuel rods; h represents the height of the active area of ​​the fuel rod.

[0266] In some implementations, the second determining module 530 is specifically configured to:

[0267] Based on the full maximum linear power density, the fuel cladding damage rate in the target core is determined by the first type of procedure;

[0268] The first type of program includes at least one of a SMART program and a SAV program.

[0269] In some implementations, when the first type of program includes a SMART program, the second determination module 530 is specifically configured to:

[0270] Based on all maximum linear power densities, the target number of maximum linear power densities with a value greater than or equal to a preset power density is counted through the SMART program, and the target number is taken as the number of fuel rods with damaged cladding;

[0271] The number of fuel rods with damaged cladding and the total number of fuel rods in the target core are substituted into formula (2) through the SMART program to calculate the fuel cladding damage rate in the target core;

[0272] Among them, formula (2) includes:

[0273]

[0274] Where FR is the fuel cladding damage rate; N over Indicates the number of fuel rods with damaged cladding; N total Indicates the total number of fuel rods.

[0275] In some embodiments, the target neutron kinetic parameter includes at least one of a moderator density coefficient, a Doppler coefficient, a fast neutron lifetime, a thermal channel factor, and a thermal power peak factor;

[0276] The target power distribution includes normalized axial power distribution at different cycles and lifetimes;

[0277] The target thermal-hydraulic parameters include at least one of system pressure, core power, heat transfer coefficient between cladding and coolant, coolant temperature and maximum fuel cladding temperature.

[0278] The fuel cladding damage rate determination device provided in the embodiment of the present application can be used to execute the fuel cladding damage rate determination method, that is, it has the beneficial effects and implementation methods of the fuel cladding damage rate determination method provided in Example 1 of the present application. For details, please refer to the specific description of the fuel cladding damage rate determination method in the above Example 1, which will not be repeated in this embodiment.

[0279] Based on the same inventive concept, an embodiment of the present application further provides a fuel cladding monitoring system. The fuel cladding monitoring system provided by the embodiment of the present application is introduced below in conjunction with the accompanying drawings.

[0280] Example 4

[0281] like Figure 6 As shown, the fuel cladding monitoring system 1000 provided in the embodiment of the present application may include the fuel cladding damage rate determination device 500 of any one of Embodiments 3, and a fuel cladding monitoring device 600.

[0282] Among them, the fuel cladding damage rate determining device 500 can be connected to the fuel cladding monitoring device 600, and the fuel cladding damage rate determining device 500 can be used to determine the fuel cladding damage rates in the target core corresponding to different target burnups; the fuel cladding monitoring device 600 can be used to determine the changing relationship between the burnup and the fuel cladding damage rate based on each target burnup and its corresponding fuel cladding damage rate in the target core, so as to determine the maximum fuel cladding damage rate during the entire life cycle.

[0283] According to the fuel cladding monitoring system provided in the embodiments of the present application, the fuel cladding damage rate in the target core corresponding to different target burnups is determined through the fuel cladding damage rate determination device of any one of Embodiment 3, which can improve the accuracy of determining the fuel cladding damage rate in a large-break loss of coolant accident in a nuclear power plant. Furthermore, based on each target burnup and its corresponding fuel cladding damage rate in the target core, the changing relationship between the burnup and the fuel cladding damage rate can be determined to determine the maximum fuel cladding damage rate over the entire life cycle, thereby providing an accurate cladding damage rate for source term calculation.

[0284] The fuel cladding monitoring system provided in the embodiment of the present application can be used to execute the fuel cladding monitoring method, that is, it has the beneficial effects and implementation methods of the fuel cladding monitoring method provided in Example 2 of the present application. For details, please refer to the specific description of the fuel cladding monitoring method in the above Example 2, which will not be repeated in this embodiment.

[0285] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present application, but the present application is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of the present application, and these modifications and improvements are also considered to be within the scope of protection of the present application.

Claims

1. A method for determining a fuel cladding damage rate, characterized in that: include: Obtaining target neutron kinetic parameters, target power distribution and target burnup of the target core; Determining target fuel parameters and target thermal hydraulic parameters according to the target neutron kinetic parameters, the target power distribution, and the target burnup; A fuel cladding damage rate in a target core is determined according to the target fuel parameters and the target thermal-hydraulic parameters.

2. The method according to claim 1, characterized in that: The step of obtaining target neutron kinetic parameters, target power distribution and target burnup of the target core includes: Determining target neutron kinetic parameters, target power distribution and target burnup of the target core through the first type of program; The first type of program includes at least one of a SMART program and a SAV program.

3. The method according to claim 1, characterized in that The determining of target fuel parameters and target thermal hydraulic parameters according to the target neutron kinetic parameters, the target power distribution and the target burnup includes: Determining target fuel parameters according to the target power distribution and the target burnup, wherein the target fuel parameters include fuel parameters under different target power distributions and fuel parameters under different target fuels, and the fuel parameters include core heat storage, cladding gap, and cladding internal pressure; Target thermal hydraulic parameters are determined according to the target neutron kinetic parameters and the target power distribution.

4. The method according to claim 3, characterized in that The step of determining a target fuel parameter according to the target power distribution and the target fuel consumption includes: determining a target fuel parameter through a second type of procedure based on the target power distribution and the target burnup; The second type of program includes at least one of the COPERNIC program, the CARO program and the BETHY program.

5. The method according to claim 3, characterized in that: Determining target thermal hydraulic parameters according to the target neutron kinetic parameters and the target power distribution includes: determining target thermal hydraulic parameters through a third type of program based on the target neutron kinetic parameters and the target power distribution; The third category of programs includes any one of the CATHARE-GB program and the RELAP5 program.

6. The method according to claim 5, characterized in that The target thermal hydraulic parameters are determined by the third type of program, including: The target information includes breach spectrum, average temperature of reactor coolant system, injection box pipeline resistance, injection box temperature system and axial power distribution, and the target thermal hydraulic parameters are obtained by performing sensitivity analysis on the target information through the third type of program.

7. The method according to claim 1, characterized in that The step of determining the damage rate of the fuel cladding in the target core according to the target fuel parameter and the target thermal-hydraulic parameter comprises: Determining, according to the target fuel parameters and the target thermal-hydraulic parameters, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged; The fuel cladding damage rate in the target core is determined based on all of the maximum linear power densities.

8. The method according to claim 7, characterized in that The step of determining, based on the target fuel parameters and the target thermal-hydraulic parameters, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged comprises: Based on the target fuel parameters and the target thermal-hydraulic parameters, determining, by a fourth type of program, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged; The fourth category of procedures includes at least one of the SAHA procedure and the FRAPTRAN fuel procedure.

9. The method according to claim 8, characterized in that In the case where the fourth type of program includes the SAHA program, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged is determined by the fourth type of program based on the target fuel parameters and the target thermal-hydraulic parameters, including: The SAHA program is used to perform sensitivity analysis on the hot channel enthalpy rise factor, and the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged is obtained.

10. The method according to claim 9, characterized in that The sensitivity analysis of the hot channel enthalpy rise factor is performed by the SAHA program to obtain the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged, including: The SAHA program is used to simulate the hot rod stress corresponding to different enthalpy rise factors to determine the minimum enthalpy rise factor when the fuel cladding in the target core is not damaged; Obtaining the core power, the target axial maximum power peak, the number of fuel assemblies in the target core, the number of fuel rods in the fuel assembly, and the height of the fuel rod active area; Substituting the minimum enthalpy rise factor, the core power, the target axial maximum power peak, the number of fuel assemblies, the number of fuel rods and the height of the active area of ​​the fuel rod into formula (1) for calculation, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged is obtained; The formula (1) includes: Among them, LPD max represents the maximum linear power density; P represents the core power; P r represents the minimum enthalpy rise factor; f z,max Indicates the target axial maximum power peak; N a Indicates the number of fuel assemblies; N r represents the number of fuel rods; h represents the height of the active area of ​​the fuel rod.

11. The method according to claim 7, characterized in that Determining the damage rate of the fuel cladding in the target core according to all the maximum linear power densities includes: Based on all of the maximum linear power densities, determining the fuel cladding damage rate in the target core by a first type of procedure; The first type of program includes at least one of a SMART program and a SAV program.

12. The method according to claim 11, characterized in that In the case where the first type of program includes the SMART program, determining the fuel cladding damage rate in the target core by using the first type of program includes: Based on all the maximum linear power densities, the target number of the maximum linear power densities whose values ​​are greater than or equal to a preset power density is counted by the SMART program, and the target number is used as the number of fuel rods with damaged cladding; Substituting the number of fuel rods with damaged cladding and the total number of fuel rods in the target core into formula (2) for calculation through the SMART program, the damage rate of fuel cladding in the target core is obtained; Wherein, the formula (2) includes: Where FR is the fuel cladding damage rate; N over Indicates the number of fuel rods with damaged cladding; N total Indicates the total number of fuel rods.

13. The method according to any one of claims 1 to 12, characterized in that The target neutron kinetic parameter includes at least one of a moderator density coefficient, a Doppler coefficient, a fast neutron lifetime, a thermal channel factor, and a thermal power peak factor; The target power distribution includes normalized axial power distribution at different cycles and lifetimes; The target thermal hydraulic parameters include at least one of system pressure, core power, heat transfer coefficient between cladding and coolant, coolant temperature and maximum fuel cladding temperature.

14. A fuel cladding monitoring method, characterized in that: include: According to the method for determining the damage rate of fuel cladding according to any one of claims 1 to 13, the damage rates of fuel cladding in target cores corresponding to different target burnups are determined; According to each target burnup and its corresponding target fuel cladding damage rate in the core, the relationship between the burnup and the fuel cladding damage rate is determined to determine the maximum fuel cladding damage rate during the entire life cycle.

15. A fuel cladding damage rate determination device, characterized in that: include: A first acquisition module is used to acquire target neutron kinetic parameters, target power distribution and target burnup of a target core; a first determination module, connected to the first acquisition module, configured to determine a target fuel parameter and a target thermal hydraulic parameter according to the target neutron kinetic parameter, the target power distribution and the target burnup; The second determination module is connected to the first determination module and is used to determine the fuel cladding damage rate in the target core according to the target fuel parameters and the target thermal-hydraulic parameters.

16. The device according to claim 15, characterized in that The first acquisition module is specifically used to: Determining target neutron kinetic parameters, target power distribution and target burnup of the target core through the first type of program; The first type of program includes at least one of a SMART program and a SAV program.

17. The device according to claim 15, characterized in that The first determining module is specifically configured to: Determining target fuel parameters according to the target power distribution and the target burnup, wherein the target fuel parameters include fuel parameters under different target power distributions and fuel parameters under different target fuels, and the fuel parameters include core heat storage, cladding gap, and cladding internal pressure; Target thermal hydraulic parameters are determined according to the target neutron kinetic parameters and the target power distribution.

18. The device according to claim 15, characterized in that The second determining module is specifically used to: Determining, according to the target fuel parameters and the target thermal-hydraulic parameters, the maximum linear power density corresponding to each fuel rod when the fuel cladding in the target core is not damaged; The fuel cladding damage rate in the target core is determined based on all of the maximum linear power densities.

19. A fuel cladding monitoring system, characterized in that: include: The fuel cladding damage rate determination device according to any one of claims 15 to 18, used to determine the fuel cladding damage rates in target cores corresponding to different target burnups; The fuel cladding monitoring device is connected to the fuel cladding damage rate determination device and is used to determine the changing relationship between the burnup and the fuel cladding damage rate according to each target burnup and its corresponding target fuel cladding damage rate in the core, so as to determine the maximum fuel cladding damage rate during the entire life cycle.

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