Vapor generator heat transfer tube limit state evaluation method, system, medium and equipment

Abstract

The invention relates to a steam generator heat transfer tube limit state assessment method and system, a medium and equipment. The method comprises the following steps: acquiring defect information of a to-be-assessed heat transfer tube; the to-be-evaluated heat transfer tube is a defective steam generator heat transfer tube determined in the maintenance process; judging whether the defect type of the to-be-evaluated heat transfer tube is micro-vibration wear or not based on the defect information; if yes, the predicted actual size of the abrasion defect of the heat transfer pipe to be evaluated is calculated; if not, limit state evaluation is not carried out; calculating limit evaluation data of the heat transfer tube to be evaluated according to the predicted actual size; and performing limit state evaluation on the to-be-evaluated heat transfer tube according to the limit evaluation data. The limit state of the heat transfer pipe of the steam generator can be accurately evaluated, the situation that the steam generator is excessively and unreasonably blocked, and the operation efficiency is reduced is avoided, and meanwhile the pressure of a conservative pipe blocking strategy on the nuclear power plant overhaul efficiency can be increased.

Description

Technical Field

[0001] The present invention relates to the technical field of steam generators in nuclear power plants, and more specifically, to a method, system, medium and device for evaluating the ultimate state of heat transfer tubes of steam generators. Background Art

[0002] Currently, the "40% plugging criterion" is generally adopted for the plugging criterion of heat transfer tubes in nuclear power plants, that is, when it is expected that there will be defects exceeding 40% of the wall thickness depth on the heat transfer tubes of the steam generator, the heat transfer tubes need to be plugged.

[0003] The "40% plugging criterion" is obtained based on the infinitely long uniform corrosion defects of Inconel600 alloy heat transfer tubes. Theoretical research and engineering experience both show that this criterion is too conservative for steam generators mainly using Inconel690 alloy heat transfer tubes, which will lead to excessive and unreasonable plugging of steam generators, reducing the operating efficiency and even causing premature scrapping. In addition, the overly conservative plugging strategy also brings great pressure to the maintenance efficiency of nuclear power plants. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method, system, medium and device for evaluating the ultimate state of heat transfer tubes of steam generators in view of the problems existing in the prior art.

[0005] The technical solution adopted by the present invention to solve its technical problems is: to construct a method for evaluating the ultimate state of heat transfer tubes of steam generators, including the following steps: Obtain the defect information of the heat transfer tube to be evaluated; the heat transfer tube to be evaluated is a defective heat transfer tube of the steam generator determined during the maintenance process; Based on the defect information, determine whether the defect type of the heat transfer tube to be evaluated is fretting wear; If so, calculate the predicted actual size of the wear defect of the heat transfer tube to be evaluated; if not, do not perform the ultimate state evaluation; Calculate the ultimate evaluation data of the heat transfer tube to be evaluated according to the predicted actual size; Perform the ultimate state evaluation on the heat transfer tube to be evaluated according to the ultimate evaluation data.

[0006] In the method for evaluating the ultimate state of heat transfer tubes of steam generators of the present invention, the calculation of the predicted actual size of the wear defect of the heat transfer tube to be evaluated includes: Determine the annual growth rate of fretting wear of the heat transfer tube to be evaluated; Determine the maintenance time interval of the heat transfer tube to be evaluated and the wall thickness of the heat transfer tube to be evaluated; Determine the axial length of the detection of the heat transfer tube to be evaluated; Calculate according to the annual growth rate, the overhaul time interval, and the wall thickness of the heat transfer tube to be evaluated to obtain the first defect size of the heat transfer tube to be evaluated; Calculate according to the detected axial length to obtain the second defect size of the heat transfer tube to be evaluated; The first defect size and the second defect size are the actual sizes of the prediction.

[0007] In the method for evaluating the ultimate state of the heat transfer tube of the steam generator according to the present invention, the first defect size is calculated by the following formula: ; Wherein, is the first defect size; is the detected defect depth; Gr is the annual growth rate of the fretting wear defect; Δ t is the time interval from this overhaul to the next overhaul; TW is the wall thickness of the heat transfer tube.

[0008] In the method for evaluating the ultimate state of the heat transfer tube of the steam generator according to the present invention, the second defect size is calculated by the following formula: ; Wherein, is the second defect size; L is the detected axial length.

[0009] In the method for evaluating the ultimate state of the heat transfer tube of the steam generator according to the present invention, the ultimate evaluation data is the bursting pressure of the heat transfer tube to be evaluated; Calculating the ultimate evaluation data of the heat transfer tube to be evaluated according to the predicted actual size includes: Calculate according to the first defect size and the second defect size to obtain the bursting pressure of the heat transfer tube to be evaluated.

[0010] In the method for evaluating the ultimate state of the heat transfer tube of the steam generator according to the present invention, the bursting pressure of the heat transfer tube to be evaluated is calculated by the following formula: ; Wherein, P is the bursting pressure of the heat transfer tube to be evaluated.

[0011] In the method for evaluating the ultimate state of the heat transfer tube of the steam generator according to the present invention, the ultimate evaluation data is the bursting pressure of the heat transfer tube to be evaluated; Evaluating the ultimate state of the heat transfer tube to be evaluated according to the ultimate evaluation data includes: Compare the bursting pressure with the ultimate bearing pressure; If the bursting pressure is less than the ultimate bearing pressure, it is determined that the heat transfer tube to be evaluated reaches the ultimate state; If the bursting pressure is greater than the ultimate bearing pressure, it is determined that the heat transfer tube to be evaluated does not reach the ultimate state.

[0012] The present invention also provides a system for evaluating the ultimate state of a heat transfer tube of a steam generator, including: A defect acquisition unit for acquiring defect information of the heat transfer tube to be evaluated; the heat transfer tube to be evaluated is a defective heat transfer tube of a steam generator determined during maintenance; A type judgment unit for judging whether the defect type of the heat transfer tube to be evaluated is fretting wear based on the defect information; A size calculation unit for calculating the predicted actual size of the wear defect of the heat transfer tube to be evaluated when the defect of the heat transfer tube to be evaluated is fretting wear; An ultimate evaluation data calculation unit for calculating the ultimate evaluation data of the heat transfer tube to be evaluated according to the predicted actual size; An ultimate state evaluation unit for performing an ultimate state evaluation on the heat transfer tube to be evaluated according to the ultimate evaluation data.

[0013] The present invention also provides a storage medium storing a computer program, and the computer program is suitable for being loaded by a processor to execute the steps of the method for evaluating the ultimate state of a heat transfer tube of a steam generator as described above.

[0014] The present invention also provides an electronic device including a memory and a processor, wherein a computer program is stored in the memory, and the processor executes the steps of the method for evaluating the ultimate state of a heat transfer tube of a steam generator as described above by calling the computer program stored in the memory.

[0015] Implementing the method, system, medium and device for evaluating the ultimate state of a heat transfer tube of a steam generator of the present invention has the following beneficial effects: including the following steps: acquiring defect information of the heat transfer tube to be evaluated; the heat transfer tube to be evaluated is a defective heat transfer tube of a steam generator determined during maintenance; judging whether the defect type of the heat transfer tube to be evaluated is fretting wear based on the defect information; if so, calculating the predicted actual size of the wear defect of the heat transfer tube to be evaluated; if not, not performing an ultimate state evaluation; calculating the ultimate evaluation data of the heat transfer tube to be evaluated according to the predicted actual size; performing an ultimate state evaluation on the heat transfer tube to be evaluated according to the ultimate evaluation data. Through the present invention, an accurate evaluation of the ultimate state of the heat transfer tube of a steam generator can be achieved, avoiding excessive and unreasonable plugging of the steam generator to reduce the operation efficiency, and at the same time, it can also increase the pressure on the maintenance efficiency of nuclear power plants with a conservative plugging strategy. Description of the Drawings

[0016] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. In the drawings: Figure 1 is a schematic flowchart of an embodiment of the method for evaluating the limit state of the heat transfer tubes of a steam generator provided by the present invention; Figure 2 is a logical block diagram of the system for evaluating the limit state of the heat transfer tubes of a steam generator provided by the present invention. Detailed implementation manners

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0018] To solve the problems existing in the prior art, the present invention provides a method for evaluating the limit state of the heat transfer tubes of a steam generator. This method can calculate and evaluate the limit state of the heat transfer tubes of a steam generator more accurately, providing technical support for plugging or repairing the heat transfer tubes.

[0019] Refer to Figure 1 , in a preferred embodiment, the method for evaluating the limit state of the heat transfer tubes of a steam generator includes the following steps: Step S100: Obtain the defect information of the heat transfer tube to be evaluated.

[0020] Among them, the heat transfer tube to be evaluated is a defective heat transfer tube of a steam generator determined during the overhaul process. Optionally, in some embodiments, the defect information of the heat transfer tube to be evaluated may include, but is not limited to, the defect size, defect morphology, defect detection signal, defect location information, etc. of the heat transfer tube to be evaluated. Among them, the defect information of the heat transfer tube to be evaluated can be obtained through various methods, such as directly calling from the system database, or can also be directly detected by on-site detection equipment. The present invention does not limit this, as long as it can meet the acquisition of defect information. It should be noted that in the embodiments of the present invention, the heat transfer tube to be evaluated is a heat transfer tube of a steam generator that has been found to be defective during the overhaul.

[0021] Step S200: Based on the defect information, determine whether the defect type of the heat transfer tube to be evaluated is fretting wear.

[0022] Optionally, in some embodiments, the determination of the type of defect of the heat transfer tube to be evaluated is as follows: First, obtain the defect detection signal of the heat transfer tube to be evaluated (such as the eddy current signal of the heat transfer tube to be evaluated), and determine whether it is a wear defect according to this defect detection signal. If it is a wear defect, further identify whether it is fretting wear. The identification of fretting wear can be carried out according to the location where the wear occurs. For example, if the wear occurs on the anti-vibration strip of the heat transfer tube to be evaluated, or the wear occurs near the support plate, it can be determined that the wear is fretting wear. Then perform step S300. If it is not a defect of fretting wear, it is not necessary to perform the limit state evaluation on the heat transfer tube to be evaluated. That is, the present invention is directed to the limit state evaluation of the steam generator heat transfer tube with fretting wear defects.

[0023] Step S300: If so, calculate the predicted actual size of the wear defect of the heat transfer tube to be evaluated; if not, do not perform the limit state evaluation.

[0024] Optionally, in some embodiments, calculating the predicted actual size of the wear defect of the heat transfer tube to be evaluated includes: determining the annual growth rate of fretting wear of the heat transfer tube to be evaluated; determining the maintenance time interval of the heat transfer tube to be evaluated and the wall thickness of the heat transfer tube to be evaluated; determining the detected axial length of the heat transfer tube to be evaluated; calculating according to the annual growth rate, the maintenance time interval and the wall thickness of the heat transfer tube to be evaluated to obtain the first defect size of the heat transfer tube to be evaluated; calculating according to the detected axial length to obtain the second defect size of the heat transfer tube to be evaluated. Among them, the first defect size and the second defect size are predicted actual sizes.

[0025] Specifically, the first defect size of the heat transfer tube to be evaluated is calculated by the following formula: (1).

[0026] Wherein, is the first defect size, which is the predicted actual defect depth; is the detected defect depth, which can be detected by the eddy current detection method. 0.9605 and 13.2 are obtained by fitting the eddy current detection test results, and 1.2 is the safety factor. Gr is the annual growth rate of fretting wear defects; Gr The specific data of can be determined by the specific steam generator maintenance historical data. Δ t is the time interval from this maintenance to the next maintenance; TW (wall thickness) represents the wall thickness of the heat transfer tube, and adding "%" represents the ratio of the defect depth divided by the wall thickness. For example, in an inspection, the defect depth is found to be 20% ( ), the defect growth rate is 5% / year ( Gr ), then 1.5 years (Δ t), the actual defect depth = 0.9605×20 + 13.2 + 1.2×5×1.5 = 41.41, that is, after 1.5 years, the predicted actual depth of this defect is 41.41%.

[0027] The second defect size of the heat transfer tube to be evaluated is calculated through formal calculation: (2).

[0028] Among them, is the second defect size, which is the predicted actual axial length of the defect; L is the detected axial length, that is L is a parameter related to the position where fretting wear occurs. 1.2 is the safety factor. For fretting wear at the anti-vibration bar (AVB), L = 11 mm; for fretting wear at the support plate (TSP), L = 30 mm. It should be noted that is the actual axial length of the defect considering uncertainty, L is the axial length obtained through non-destructive testing, that is, the length of the defect along the axial direction of the heat transfer tube. Among them, L can also be expressed as .

[0029] Step S400: Calculate the limit evaluation data of the heat transfer tube to be evaluated according to the predicted actual size.

[0030] Optionally, in the embodiment of the present invention, the limit evaluation data is the bursting pressure of the heat transfer tube to be evaluated. By calculating the bursting pressure, the limit state of the heat transfer tube to be evaluated can be evaluated. Specifically, in some embodiments, calculating the limit evaluation data of the heat transfer tube to be evaluated according to the predicted actual size includes: calculating according to the first defect size and the second defect size to obtain the bursting pressure of the heat transfer tube to be evaluated. Among them, the bursting pressure of the heat transfer tube to be evaluated is calculated by the following formula: (3).

[0031] Among them, P is the bursting pressure of the heat transfer tube to be evaluated; 60 is determined according to the bursting test of the heat transfer tube, which is the bursting pressure of the defect-free heat transfer tube; 1.09594 and 0.102 are the coefficients of the heat transfer tube bursting pressure prediction model established through numerical simulation regression.

[0032] Step S500: Perform a limit state evaluation on the heat transfer tube to be evaluated according to the limit evaluation data.

[0033] In step S400, the PAfter obtaining the value, the limit state can be evaluated. Optionally, in some embodiments, the limit state evaluation of the heat transfer tube to be evaluated based on the limit evaluation data includes: comparing the burst pressure with the limit bearing pressure; if the burst pressure is less than the limit bearing pressure, it is determined that the heat transfer tube to be evaluated reaches the limit state; if the burst pressure is greater than the limit bearing pressure, it is determined that the heat transfer tube to be evaluated does not reach the limit state. Among them, the limit bearing pressure is the limit bearing pressure of the heat transfer tube required in the steam generator maintenance code (denoted by For example P r = 25.83 MPa).

[0034] Specifically, for the fretting wear defect of the heat transfer tube to be evaluated that has been detected ( α NDE , L NDE ), first calculate the predicted actual size of the fretting wear defect of the heat transfer tube to be evaluated through the aforementioned formulas (1) and (2) ( , ), then the burst pressure of the heat transfer tube to be evaluated can be calculated according to formula (3) P , and then compare the calculated burst pressure P with the limit bearing pressure . If the comparison result is: ; Then it can be determined that the heat transfer tube to be evaluated does not reach the limit state, that is, this fretting wear defect can be left untreated. Otherwise, it is determined that the heat transfer tube to be evaluated reaches the limit state, and the heat transfer tube to be evaluated needs to be plugged or repaired.

[0035] Through the present invention, a suitable calculation and evaluation of the limit state of the steam generator heat transfer tube can be given for fretting wear defects, which can solve the problem of the existing "40% tube plugging criterion", avoid excessive and unreasonable tube plugging, and avoid increasing the maintenance efficiency pressure of nuclear power plants due to overly conservative tube plugging strategies.

[0036] Among them, the method for evaluating the limit state of the steam generator heat transfer tube provided by the present invention can be applied to heat transfer tubes made of Inconel690 alloy with a size of φ19.05×1.09 mm. Of course, it can be understood that the method for evaluating the limit state of the steam generator heat transfer tube provided by the present invention can also be applied to heat transfer tubes of other materials and different sizes. Among them, the specific values involved in the calculation of the predicted actual size are adjusted according to heat transfer tubes of different materials and different sizes.

[0037] Referring to Figure 2 , in a preferred embodiment, the present invention provides a system for evaluating the limit state of a steam generator heat transfer tube.

[0038] As Figure 2 shown, the steam generator heat transfer tube limit state evaluation system includes: A defect acquisition unit 10 for acquiring defect information of the heat transfer tube to be evaluated. Among them, the heat transfer tube to be evaluated is a defective steam generator heat transfer tube determined during the maintenance process.

[0039] A type judgment unit 20 for judging whether the defect type of the heat transfer tube to be evaluated is fretting wear based on the defect information.

[0040] A dimension calculation unit 30 for calculating the predicted actual size of the wear defect of the heat transfer tube to be evaluated when the defect of the heat transfer tube to be evaluated is fretting wear.

[0041] A limit evaluation data calculation unit 40 for calculating the limit evaluation data of the heat transfer tube to be evaluated according to the predicted actual size.

[0042] A limit state evaluation unit 50 for performing a limit state evaluation on the heat transfer tube to be evaluated according to the limit evaluation data.

[0043] Specifically, the specific cooperation operation process among the units in the steam generator heat transfer tube limit state evaluation system here can specifically refer to the above-mentioned steam generator heat transfer tube limit state evaluation method, which will not be elaborated here.

[0044] In addition, an electronic device of the present invention includes a memory and a processor; the memory is used to store a computer program; the processor is used to execute the computer program to implement the steam generator heat transfer tube limit state evaluation method as described in any one of the above. Specifically, according to an embodiment of the present invention, the process described with reference to the flowchart above can be implemented as a computer software program. For example, an embodiment of the present invention includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes program codes for executing the method shown in the flowchart. In such an embodiment, when the computer program is downloaded and installed by the electronic device and executed, it executes the above-mentioned functions defined in the method of the embodiment of the present invention. The electronic device in the present invention can be a terminal such as a notebook, a desktop computer, a tablet computer, a smart phone, etc., or a server.

[0045] In addition, a storage medium of the present invention stores a computer program, and when the computer program is executed by a processor, it implements the method for evaluating the ultimate state of the heat transfer tubes of the steam generator described in any one of the above. Specifically, it should be noted that the storage medium of the present invention described above can be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of a computer-readable storage medium can include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable storage medium can be any tangible medium that contains or stores a program, and this program can be used by or in combination with an instruction execution system, apparatus, or device. In the present invention, a computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, which carries computer-readable program code. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, and this computer-readable signal medium can send, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device. The program code contained on a computer-readable medium can be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0046] The above computer-readable medium can be included in the above electronic device; or it can exist separately without being assembled into the electronic device.

[0047] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts among the embodiments can be referred to each other. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

[0048] Those skilled in the art may further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0049] The steps of the methods or algorithms described in combination with the embodiments disclosed herein can be directly implemented by hardware, software modules executed by a processor, or a combination of the two. The software modules can be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium well known in the technical field.

[0050] The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and shall not limit the protection scope of the present invention. All equivalent changes and modifications made to the scope of the claims of the present invention shall fall within the scope covered by the claims of the present invention.

Claims

1. A steam generator heat transfer tube limit state assessment method, characterized in that: The following steps are involved: Obtaining defect information of a heat transfer tube to be evaluated; the heat transfer tube to be evaluated is a defective steam generator heat transfer tube determined during the overhaul process; Determining whether the defect type of the heat transfer tube to be evaluated is fretting wear based on the defect information; The determining whether the defect type of the heat transfer tube to be evaluated is fretting wear based on the defect information includes: acquiring a defect detection signal of the heat transfer tube to be evaluated, determining whether it is a wear defect according to the defect detection signal, and if it is a wear defect, determining whether the wear defect is on the anti-vibration strip or the support plate of the heat transfer tube to be evaluated, and determining that it is fretting wear; If yes, the predicted actual size of the wear defect of the heat transfer tube to be evaluated is calculated; if no, the limit state evaluation is not performed; the calculation of the predicted actual size of the wear defect of the heat transfer tube to be evaluated includes: determining the annual growth rate of the micro-vibration wear of the heat transfer tube to be evaluated; determining the maintenance time interval of the heat transfer tube to be evaluated and the wall thickness of the heat transfer tube to be evaluated; determining the axial length of the heat transfer tube to be evaluated; calculating according to the annual growth rate, the maintenance time interval and the wall thickness of the heat transfer tube to be evaluated, to obtain the first defect size of the heat transfer tube to be evaluated; calculating according to the detected axial length, to obtain the second defect size of the heat transfer tube to be evaluated; the first defect size and the second defect size are the predicted actual sizes; the first defect size is calculated by the following formula: ； in, is the first defect size; is the depth of the defect detected; Gr is the annual growth rate of fretting defects; Δ t is the time interval from this maintenance to the next maintenance; TW is the wall thickness of the heat transfer tube; Calculating the limit evaluation data of the heat transfer tube to be evaluated according to the predicted actual size; A limit state assessment is performed on the heat transfer tube to be assessed according to the limit assessment data.

2. The steam generator heat transfer tube limit state assessment method according to claim 1, characterized in that: The second defect size is formally calculated by: ； in, is the second defect size; L is the axial length of the test.

3. The steam generator heat transfer tube limit state assessment method according to claim 2, characterized in that: The limit evaluation data is the bursting pressure of the heat transfer tube to be evaluated; The step of calculating the limit evaluation data of the heat transfer tube to be evaluated according to the predicted actual size includes: The bursting pressure of the heat transfer tube to be evaluated is obtained by performing calculation according to the first defect size and the second defect size.

4. The steam generator heat transfer tube limit state assessment method according to claim 3, characterized in that: The bursting pressure of the heat transfer tube to be evaluated is calculated by the following formula: ； in, P is the bursting pressure of the heat transfer tube to be evaluated.

5. The steam generator heat transfer tube limit state assessment method according to claim 1, characterized in that: The limit evaluation data is the bursting pressure of the heat transfer tube to be evaluated; The performing limit state assessment on the heat transfer tube to be assessed according to the limit assessment data comprises: comparing the burst pressure with a limit bearing pressure; If the bursting pressure is less than the limit bearing pressure, it is determined that the heat transfer tube to be evaluated has reached the limit state; If the bursting pressure is greater than the ultimate bearing pressure, it is determined that the heat transfer tube to be evaluated has not reached the limit state.

6. A steam generator heat transfer tube limit state assessment system, characterized in that: include: A defect acquisition unit, used to acquire defect information of the heat transfer tube to be evaluated; The heat transfer tube to be evaluated is a defective heat transfer tube of a steam generator determined during the overhaul process; A type judgment unit, used for judging whether the defect type of the heat transfer tube to be evaluated is fretting wear based on the defect information; The determining whether the defect type of the heat transfer tube to be evaluated is fretting wear based on the defect information includes: acquiring a defect detection signal of the heat transfer tube to be evaluated, determining whether it is a wear defect according to the defect detection signal, and if it is a wear defect, determining whether the wear defect is on the anti-vibration strip or the support plate of the heat transfer tube to be evaluated, and determining that it is fretting wear; A size calculation unit is used to calculate the predicted actual size of the wear defect of the heat transfer tube to be evaluated when the defect of the heat transfer tube to be evaluated is fretting wear; the calculation of the predicted actual size of the wear defect of the heat transfer tube to be evaluated includes: determining the annual growth rate of the fretting wear of the heat transfer tube to be evaluated; determining the maintenance time interval of the heat transfer tube to be evaluated and the wall thickness of the heat transfer tube to be evaluated; determining the detected axial length of the heat transfer tube to be evaluated; calculating according to the annual growth rate, the maintenance time interval and the wall thickness of the heat transfer tube to be evaluated to obtain the first defect size of the heat transfer tube to be evaluated; calculating according to the detected axial length to obtain the second defect size of the heat transfer tube to be evaluated; the first defect size and the second defect size are the predicted actual sizes; the first defect size is calculated by the following formula: ； in, is the first defect size; is the depth of the defect detected; Gr is the annual growth rate of fretting defects; Δ t is the time interval from this maintenance to the next maintenance; TW is the wall thickness of the heat transfer tube; A limit evaluation data calculation unit, used for calculating the limit evaluation data of the heat transfer tube to be evaluated according to the predicted actual size; A limit state assessment unit is used to perform a limit state assessment on the heat transfer tube to be assessed according to the limit assessment data.

7. A storage medium, characterized in that: The storage medium stores a computer program, and the computer program is suitable for being loaded by a processor to execute the steps of the method for evaluating the limit state of a heat transfer tube of a steam generator according to any one of claims 1 to 5.

8. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and the processor executes the steps of the method for evaluating the limit state of a heat transfer tube of a steam generator according to any one of claims 1 to 5 by calling the computer program stored in the memory.

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