A fusion pi controller nuclear fuel cladding wall thickness eddy current measurement method

Abstract

The application provides a nuclear fuel cladding wall thickness eddy current measurement method fusing a PI controller, coaxial excitation coils and receiving coils are arranged outside the cladding tube, the receiving coils are located on the side close to the cladding tube, the axis of the receiving coils is perpendicular to the axis of the cladding tube, the method comprises the following steps: obtaining parameter values of multiple types of parameters of the cladding tube parameters, the receiving coil parameters and the distance parameters between the receiving coils and the cladding tube, and detecting the results of the mutual inductance of the coils; establishing a cladding tube eddy current analytical theory model, the input data of the model comprises the cladding tube parameters, the receiving coil parameters and the distance parameters, and the output data is the mutual inductance of the coils; setting an initial value of a control variable of the PI controller, taking the value of the cladding tube thickness in the cladding tube parameters as the initial value of the control variable, obtaining the calculation results of the mutual inductance of the coils by using the cladding tube eddy current analytical theory model based on the obtained parameter values of the multiple types of parameters; and updating the control variable of the PI controller by combining the calculation results and the detection results of the mutual inductance of the coils to obtain the measurement results of the cladding tube thickness.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power cladding tube wall thickness measurement using electromagnetic eddy current, and in particular to a nuclear fuel cladding wall thickness eddy current measurement method integrating a PI controller. Background Art

[0002] Fuel assemblies, as heat-releasing components within nuclear reactors, are the energy source for nuclear power generation. Zirconium alloy is currently the most commonly used fuel cladding material due to its advantages, including a small thermal neutron absorption cross-section, high thermal conductivity, high melting point, excellent resistance to water-side corrosion, and high mechanical strength. Zirconium-based nuclear fuel cladding serves as the primary pressure boundary and safety barrier in nuclear power plants, effectively preventing the escape of nuclear fission products while dissipating heat energy and protecting the fuel from cooling corrosion. Although zirconium-based cladding exhibits excellent corrosion resistance, it is subject to long-term erosion and corrosion from the intense neutron irradiation, high pressure (≥15.5 MPa), high temperature (300-500°C), and high-velocity circulating water within the reactor, which can easily lead to tube wall thinning, which in turn can induce hydrogen embrittlement, microcracks, and hydrogen blistering. Therefore, accurate cladding tube wall thickness measurement can ensure the safe and stable operation of nuclear power plants and prevent accidents. Summary of the Invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, the first object of the present invention is to propose a nuclear fuel cladding wall thickness eddy current measurement method integrating a PI controller to achieve high-precision cladding tube wall thickness measurement.

[0005] The second object of the present invention is to provide a nuclear fuel cladding wall thickness eddy current measurement system integrated with a PI controller.

[0006] A third object of the present invention is to provide an electronic device.

[0007] A fourth object of the present invention is to provide a computer-readable storage medium.

[0008] To achieve the above objectives, the present invention, in a first aspect, proposes a method for measuring the wall thickness of a nuclear fuel cladding using eddy currents integrated with a PI controller. An eddy current sensor is arranged outside a nuclear fuel cladding tube. The eddy current sensor includes a coaxial excitation coil and a receiving coil. The receiving coil is located near the cladding tube, and the axis of the receiving coil is perpendicular to the axis of the cladding tube. The method comprises:

[0009] Obtain parameter values ​​of multiple parameters including cladding tube parameters, receiving coil parameters, and distance parameters between the receiving coil and the cladding tube, and obtain a detection result of the coil mutual inductance detected by the eddy current sensor;

[0010] Establishing a theoretical model for eddy current analysis of a cladding tube, wherein input data of the theoretical model include cladding tube parameters, receiving coil parameters, and distance parameters, and output data is coil mutual inductance;

[0011] Setting an initial value of a control variable of a PI controller, setting a value of the cladding tube thickness in the cladding tube parameter as the initial value of the control variable, and obtaining a calculation result of the coil mutual inductance using the cladding tube eddy current analytical theoretical model based on the obtained parameter values ​​of the multiple types of parameters;

[0012] Calculate the error between the calculation result of the coil mutual inductance and the detection result of the detected coil mutual inductance. If the error does not meet the error requirement, update the control variable of the PI controller based on the error until the error meets the error requirement or the number of updates meets the update requirement, so as to obtain the final value of the control variable. The final value of the control variable is the measurement result of the cladding tube thickness.

[0013] In the method of the first aspect of the present invention, the cladding tube parameters include the cladding tube thickness, the inner and outer diameters of the cladding tube, and the electrical conductivity of the cladding tube; the receiving coil parameters include the number of coil turns, the inner and outer diameters of the coil, and the coil height; the distance parameters include the lifting distance and the distance from the receiving coil to the axis of the cladding tube.

[0014] In the method of the first aspect of the present invention, the error meeting the error requirement means that the error at the current moment is less than or equal to a set error threshold.

[0015] In the method of the first aspect of the present invention, the error between the calculated result of the coil mutual inductance and the detected result of the detected coil mutual inductance includes the current moment error and the cumulative error, and the control variable of the PI controller is updated based on the error, including: obtaining the updated control variable based on the product of the proportional coefficient of the PI controller and the current moment error, and the product of the integral coefficient of the PI controller and the cumulative error.

[0016] To achieve the above-mentioned object, the second aspect of the present invention provides a nuclear fuel cladding wall thickness eddy current measurement system integrated with a PI controller, comprising:

[0017] The eddy current detection device includes an eddy current sensor, which is arranged outside the nuclear fuel cladding tube. The eddy current sensor includes a coaxial excitation coil and a receiving coil. The receiving coil is located near the cladding tube, and the axis of the receiving coil is perpendicular to the axis of the cladding tube. The eddy current sensor is used to obtain the detection result of the coil mutual inductance;

[0018] A parameter acquisition module is used to obtain parameter values ​​of multiple parameters such as cladding tube parameters, receiving coil parameters, and distance parameters between the receiving coil and the cladding tube, and to obtain detection results of the coil mutual inductance detected by the eddy current sensor;

[0019] A modeling module is used to establish a theoretical model of eddy current analysis of the cladding tube, wherein the input data of the theoretical model include cladding tube parameters, receiving coil parameters and distance parameters, and the output data is the coil mutual inductance;

[0020] A calculation module is used to set an initial value of a control variable of a PI controller, take the value of the cladding tube thickness in the cladding tube parameter as the initial value of the control variable, obtain a calculation result of the coil mutual inductance based on the obtained parameter values ​​of multiple types of parameters using the eddy current analytical theoretical model of the cladding tube, calculate the error between the calculation result of the coil mutual inductance and the detection result of the detected coil mutual inductance, and if the error does not meet the error requirement, update the control variable of the PI controller based on the error until the error meets the error requirement or the number of updates meets the update requirement, so as to obtain a final value of the control variable, wherein the final value of the control variable is the measurement result of the cladding tube thickness.

[0021] In the system of the second aspect of the present invention, in the parameter acquisition module, the cladding tube parameters include the cladding tube thickness, the inner and outer diameters of the cladding tube, and the electrical conductivity of the cladding tube; the receiving coil parameters include the number of coil turns, the inner and outer diameters of the coil, and the coil height; the distance parameters include the lifting distance and the distance from the receiving coil to the axis of the cladding tube.

[0022] In the system of the second aspect of the present invention, in the calculation module, the error meeting the error requirement means that the error at the current moment is less than or equal to a set error threshold.

[0023] In the system of the second aspect of the present invention, in the calculation module, the error between the calculation result of the coil mutual inductance and the detection result of the detected coil mutual inductance includes the current moment error and the cumulative error, and the control variable of the PI controller is updated based on the error, including: obtaining the updated control variable based on the product of the proportional coefficient of the PI controller and the current moment error, and the product of the integral coefficient of the PI controller and the cumulative error.

[0024] To achieve the above-mentioned purpose, the third aspect of the present invention proposes an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method proposed in the first aspect of the present invention.

[0025] To achieve the above-mentioned purpose, the fourth aspect of the present invention proposes a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the method proposed in the first aspect of the present invention.

[0026] The present invention provides a nuclear fuel cladding wall thickness eddy current measurement method, system, electronic device and storage medium integrated with a PI controller. An eddy current sensor is arranged on the outside of the nuclear fuel cladding tube. The eddy current sensor includes a coaxial excitation coil and a receiving coil. The receiving coil is located near the cladding tube, and the axis of the receiving coil is perpendicular to the axis of the cladding tube. The method obtains parameter values ​​of multiple parameters such as cladding tube parameters, receiving coil parameters, and distance parameters between the receiving coil and the cladding tube, and obtains detection results of coil mutual inductance detected by the eddy current sensor; establishes a cladding tube eddy current analytical theoretical model, and the input data of the cladding tube eddy current analytical theoretical model include cladding tube parameters , receive coil parameters and distance parameters, and output data as coil mutual inductance; set the initial value of the control variable of the PI controller, let the value of the cladding tube thickness in the cladding tube parameters be the initial value of the control variable, and use the eddy current analytical theoretical model of the cladding tube based on the obtained parameter values ​​of multiple types of parameters to obtain the calculation result of the coil mutual inductance; calculate the error between the calculation result of the coil mutual inductance and the detection result of the detected coil mutual inductance. If the error does not meet the error requirement, update the control variable of the PI controller based on the error until the error meets the error requirement or the number of updates meets the update requirement, so as to obtain the final value of the control variable, and the final value of the control variable is the measurement result of the cladding tube thickness. In this case, eddy current sensors are placed on the exterior of the nuclear fuel cladding tubes. They induce eddy currents on and near the cladding tube surface to measure coil mutual inductance. A theoretical cladding tube eddy current analysis model is established, integrating multiple parameters, including cladding tube parameters, receiving coil parameters, and the distance between the receiving coil and the cladding tube. The cladding tube thickness, among the cladding tube parameters, is used as the initial value of the control variable of a PI controller. Based on the acquired values ​​of these multiple parameters, the cladding tube eddy current analysis model is used to calculate the coil mutual inductance. The PI controller's control variable is then updated based on the error between the calculated coil mutual inductance and the measured coil mutual inductance to obtain the final value of the control variable, thereby measuring the cladding tube thickness. This achieves high-precision cladding tube wall thickness measurement.

[0027] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0029] Figure 1 Schematic diagram of the eddy current sensor provided in an embodiment of the present invention detecting the base shell of the pickaxe;

[0030] Figure 2 A schematic flow chart of a method for measuring the wall thickness of a nuclear fuel cladding using eddy currents and a PI controller in accordance with an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of a specific process of the eddy current measurement method for nuclear fuel cladding wall thickness integrating a PI controller provided in an embodiment of the present invention;

[0032] Figure 4 Calculation results of the mutual inductance of the cladding shell provided by the embodiment of the present invention;

[0033] Figure 5 A graph showing the error between the calculated and measured results of the mutual inductance of the cladding shell provided by an embodiment of the present invention;

[0034] Figure 6 This is a graph showing the output results of the PI controller control variables provided by an embodiment of the present invention;

[0035] Figure 7 This is a block diagram of a nuclear fuel cladding wall thickness eddy current measurement system integrated with a PI controller provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0037] The following describes a method and system for measuring the wall thickness of a nuclear fuel cladding using eddy currents and integrating a PI controller according to an embodiment of the present invention with reference to the accompanying drawings.

[0038] The embodiment of the present invention provides a nuclear fuel cladding wall thickness eddy current measurement method integrated with a PI controller to achieve high-precision cladding tube wall thickness measurement. The nuclear fuel cladding of the present invention can be a nuclear fuel cladding based on a metallurgy.

[0039] In the present invention, an eddy current detection device is constructed. The eddy current detection device includes an eddy current sensor. The eddy current sensor is used to induce eddy currents on the surface and near the surface of the cladding tube, and the detection results of the mutual inductance of the coils are detected. Specifically, the eddy current sensor is arranged on the outside of the nuclear fuel cladding tube. The eddy current sensor includes a coaxial excitation coil and a receiving coil. The receiving coil is located on the near side of the cladding tube, and the excitation coil is located on the far side of the cladding tube. The parameters of the excitation coil and the receiving coil are the same. The axis of the receiving coil is perpendicular to the axis of the cladding tube. An alternating current is passed through the excitation coil to induce eddy currents on the surface and near the surface of the cladding tube.

[0040] Figure 1 This is a schematic diagram of the eddy current sensor provided in an embodiment of the present invention detecting the base shell of the pickaxe.

[0041] like Figure 1As shown in the figure, the excitation coil and receiving coil of the eddy current sensor are arranged outside the nuclear fuel cladding tube (referred to as the cladding). The excitation coil and receiving coil are coaxially arranged. The receiving coil is located near the cladding tube, and the excitation coil is located far from the cladding tube. The axis of the receiving coil or the excitation coil is perpendicular to the axis of the cladding tube. The cladding tube thickness (wall thickness) can be represented by c.

[0042] Figure 2 A schematic flow chart of a method for measuring the wall thickness of a nuclear fuel cladding using eddy currents and a PI controller is provided in accordance with an embodiment of the present invention.

[0043] like Figure 2 As shown, the nuclear fuel cladding wall thickness eddy current measurement method integrating the PI controller includes the following steps:

[0044] Step S101 , obtaining parameter values ​​of multiple parameters including cladding tube parameters, receiving coil parameters, and distance parameters between the receiving coil and the cladding tube, and obtaining detection results of coil mutual inductance detected by an eddy current sensor.

[0045] In step S101 , the cladding tube parameters include the cladding tube thickness, the inner and outer diameters of the cladding tube, and the electrical conductivity of the cladding tube.

[0046] In step S101, the receiving coil parameters include the number of coil turns, the inner and outer diameters of the coil, and the coil height. The receiving coil parameters are equal to the excitation coil parameters. The receiving coil parameters and the excitation coil parameters together constitute the sensor size.

[0047] In step S101 , the distance parameters include the lift-off distance and the distance from the receiving coil to the axis of the cladding tube.

[0048] Step S102 : establishing a theoretical analytical model of eddy currents of a cladding tube. The input data of the theoretical analytical model of eddy currents of a cladding tube include parameters of the cladding tube, parameters of the receiving coil, and distance parameters. The output data is the mutual inductance of the coils.

[0049] In step S102 , the input data of the cladding tube eddy current analytical theoretical model also includes excitation current, excitation angular frequency, spatial resolution, etc.

[0050] Step S103, setting the initial value of the control variable of the PI controller, taking the value of the cladding tube thickness in the cladding tube parameters as the initial value of the control variable, and obtaining the calculation result of the coil mutual inductance using the cladding tube eddy current analytical theoretical model based on the obtained parameter values ​​of multiple types of parameters.

[0051] In step S103, the value of the cladding tube thickness in the cladding tube parameters is set as the initial value of the control variable, and the obtained parameter values ​​of multiple types of parameters are input into the cladding tube eddy current analytical theoretical model to output the calculation result of the coil mutual inductance.

[0052] Step S104: Calculate the error between the calculation result of the coil mutual inductance and the detection result of the detected coil mutual inductance. If the error does not meet the error requirement, update the control variable of the PI controller based on the error until the error meets the error requirement or the number of updates meets the update requirement, so as to obtain the final value of the control variable. The final value of the control variable is the measurement result of the cladding tube thickness.

[0053] In step S104 , the error between the calculated result of the coil mutual inductance and the detected result of the coil mutual inductance includes a current moment error and a cumulative error.

[0054] In step S104 , the error meeting the error requirement means that the error at the current moment is less than or equal to a set error threshold.

[0055] In step S104 , the number of updates meeting the update requirement means that the number of updates reaches the maximum number of updates.

[0056] In step S104 , the control variable of the PI controller is updated based on the error, including obtaining an updated control variable based on the product of the proportional coefficient of the PI controller and the error at the current moment and the product of the integral coefficient of the PI controller and the accumulated error.

[0057] In some embodiments, Figure 3 This is a schematic diagram of a specific flow chart of a method for measuring the wall thickness of a nuclear fuel cladding using eddy currents and integrating a PI controller provided in an embodiment of the present invention. Figure 4 This is a diagram showing the calculation results of the mutual inductance of the cladding provided by the embodiment of the present invention. Figure 5 This is a diagram showing the error between the calculation and measurement results of the mutual inductance of the cladding based on the embodiment of the present invention. Figure 6 This is a graph of the control variable output results of the PI controller provided in an embodiment of the present invention.

[0058] like Figure 3 As shown, the specific steps of the nuclear fuel cladding wall thickness eddy current measurement method integrating the PI controller include:

[0059] 1) Build an eddy current detection device and design an eddy current sensor consisting of a coaxial excitation and receiving coil. Specifically, the eddy current sensor is located outside the cladding tube, and the axis of the excitation coil or receiving coil inside the eddy current sensor is perpendicular to the axis of the cladding tube.

[0060] 2) The eddy current response signal caused by the cladding tube is obtained by measuring the sensor in a sweep frequency mode. Specifically, an alternating current (i.e., excitation current) is passed through the excitation coil in the eddy current sensor in a sweep frequency mode to induce eddy currents on the surface and near the surface of the cladding tube, and then the eddy current response signal caused by the cladding tube is obtained by measuring the receiving coil, thereby obtaining the detection result of the coil mutual inductance. For example, a cylindrical-excitation-receiving eddy current sensor is designed, with the inner and outer diameters of the coil being 1.5 mm and 3 mm, respectively, and the number of turns of the coil being 100. The sensor is located outside the cladding tube, and the axis of its internal coil is perpendicular to the axis of the cladding tube, such as Figure 1 The coil is excited by a sinusoidal alternating current, which induces eddy currents in the base shell. The response signal of the coil is determined by the eddy current intensity and flow range.

[0061] 3) Establish a theoretical model for eddy current analysis of nuclear fuel cladding tubes. Specifically, the calculation expression for the mutual inductance of the coils is:

[0062]

[0063] In formula (1), M a is the calculated result of the mutual inductance of the coil, I is the excitation current, μ0 is the magnetic permeability in vacuum, and m represents the order index. α is the integral variable, r1 is the inner diameter of the cladding, and c is the thickness of the cladding tube. I m is the modified Bessel function of the first kind of order m. K m is the m-th order modified Bessel function of the second kind. d represents the differential symbol. j is the imaginary part. ω represents the excitation angular frequency. σ is the cladding conductivity (i.e., the conductivity of the cladding tube).

[0064] In formula (1):

[0065]

[0066] In formula (2), n is the number of coil turns, b is the lift-off distance, and h is the coil height. e1 is the inner diameter of the coil. e2 is the outer diameter of the coil. d is the distance from the coil to the axis of the cladding tube. r0 is the diameter variable, and its range is [r e1， r e2 ].

[0067] In formula (2):

[0068]

[0069] In formula (3), j is the imaginary part. r2 is the outer diameter of the cladding. κ is the distance variable, which ranges from [r2, r2+b].

[0070] In formula (3):

[0071]

[0072] Among them, K' m K m The first derivative of .

[0073] In formula (3):

[0074]

[0075] In formula (1):

[0076]

[0077]

[0078] In formula (6), α0 is the spatial resolution, which is equal to the inverse of the inner diameter of the coil (which can be the excitation coil or the receiving coil). m For I m The first-order derivative of . In equations (6) and (7):

[0079] Λ=BE-AF (8)

[0080]

[0081] In formula (9), k is the number of updates. In formula (9)-formula (12):

[0082]

[0083] M=K' m (|α|r1) / K m (|α|r1) (15)

[0084] N=I' m (|α|r1) / I m (|α|r1) (16)

[0085] L=K m (|α|(r1+c)) / K' m (|α|r1) (17)

[0086] P=K m (α k r1) / K' m (α k r1) (18)

[0087]

[0088] In formula (13):

[0089] Q=K' m (α kr1) / K' m (α k (r1+c)) (21)

[0090] In formula (21):

[0091] J=I' m (α k r1)-QI' m (α k (r1+c)) (22)

[0092] 4) Set the electromagnetic parameters of the cladding and sensor dimensions in the analytical theoretical model. For example, set the conductivity of the cladding tube and the values ​​of the receiving coil parameters. Also obtain the values ​​of various parameters, such as the cladding tube parameters, the distance between the receiving coil and the cladding tube, the excitation current, the excitation angular frequency, and the spatial resolution.

[0093] 5) Introduce a PI controller and set the initial control variable of the PI controller. Specifically, set the initial control variable of the PI controller, which is also called the initial value of the control variable.

[0094] 6) Input the control variable as the thickness value into the analytical theoretical model and calculate the corresponding mutual inductance change result. Specifically, let the thickness of the cladding tube be the control variable (the initial value of the control variable is taken for the first calculation), and combine the parameter values ​​obtained in 4) to calculate the corresponding mutual inductance change result of the coil, that is, the calculation result M of the coil mutual inductance is obtained. a The calculation result of the mutual inductance of the coil is M a Output results for analytical theoretical models. For example, the initial control variable of the controller is 0.1, and the controller proportional and integral coefficients are set to 1 and 1×10 respectively. -3 The inner diameter r1 of the base shell is set to 4.5mm, the wall thickness is set to 1mm, and the conductivity of the shell is set to 7.4MS / m. The excitation frequency is set to 100Hz to 1MHz, and a total of 20 frequency data are measured at logarithmic intervals. The analytical theoretical model is used to calculate the coil mutual inductance results, for example Figure 4 shown.

[0095] 7) Calculate the current moment error and cumulative error between the output of the analytical theoretical model and the measurement result, and determine whether the error is greater than the threshold. Specifically, when the PI controller is updated k times, the output of the control variable is used as the cladding tube wall thickness (i.e., cladding tube thickness) c and input to the analytical theoretical model. The calculation result of the coil mutual inductance is M a The actual measurement result (i.e. the detection result of the coil mutual inductance) is M m The current moment error e k The cumulative error ee after k updates k Respectively expressed as:

[0096] ek =||M m -M a ||2 (23)

[0097] ee k =ee k-1 +e k (twenty four)

[0098] In formula (24), ee k-1 is the cumulative error after k-1 updates. Determine the error at the current moment e k Is it greater than the corresponding threshold? The error change (i.e., deviation change) between the analytical calculation model and the actual measurement results at different times, for example Figure 5 shown.

[0099] 8) If yes, the error is input to the PI controller and the control variable is updated.

[0100] Specifically, if the error at the current moment is greater than the corresponding threshold, then the error at the current moment e k The cumulative error ee after k updates k Input to the PI controller to control the variable u k Update and control variable u k As the cladding tube wall thickness value input to the analytical theoretical model; control variable u k The update formula is:

[0101] u k =K p e k +K I ee k (25)

[0102] Where K p and K I Represents the proportional coefficient and integral coefficient of the PI controller respectively. For example, when the kth update is made, the control variable is u k =1×e k +1×10 -3 ee k The control variable output results for each iteration (i.e., each update number) are as follows: Figure 6 shown.

[0103] 9) If not, output the control variable, which is the cladding thickness measurement result.

[0104] Specifically, if the error at the current moment is less than or equal to the corresponding threshold within the maximum number of updates, the final control variable value is output, and the output result is the cladding thickness measurement result.

[0105] It should be noted that if the update number reaches the maximum update number and the error is still not less than the corresponding threshold, the control variable obtained by the last update is output as the cladding thickness measurement result.

[0106] In order to implement the above embodiment, the present invention also proposes a nuclear fuel cladding wall thickness eddy current measurement system integrated with a PI controller.

[0107] Figure 7 This is a block diagram of a nuclear fuel cladding wall thickness eddy current measurement system integrated with a PI controller provided by an embodiment of the present invention.

[0108] like Figure 7 As shown, the nuclear fuel cladding wall thickness eddy current measurement system integrating the PI controller includes an eddy current detection device 11, a parameter acquisition module 12, a modeling module 13 and a calculation module 14, wherein:

[0109] The eddy current detection device 11 includes an eddy current sensor, which is arranged outside the nuclear fuel cladding tube. The eddy current sensor includes a coaxial excitation coil and a receiving coil. The receiving coil is located near the cladding tube, and the axis of the receiving coil is perpendicular to the axis of the cladding tube. The eddy current sensor is used to obtain the detection result of the coil mutual inductance;

[0110] The parameter acquisition module 12 is used to obtain the parameter values ​​of multiple parameters such as the cladding tube parameters, the receiving coil parameters, and the distance parameters between the receiving coil and the cladding tube, and to obtain the detection result of the coil mutual inductance detected by the eddy current sensor;

[0111] Modeling module 13, used to establish a theoretical analytical model of eddy current of cladding tube, the input data of which include cladding tube parameters, receiving coil parameters and distance parameters, and the output data is the coil mutual inductance;

[0112] The calculation module 14 is used to set the initial value of the control variable of the PI controller, take the value of the cladding tube thickness in the cladding tube parameter as the initial value of the control variable, and obtain the calculation result of the coil mutual inductance based on the parameter values ​​of the obtained multiple types of parameters using the eddy current analytical theoretical model of the cladding tube; calculate the error between the calculation result of the coil mutual inductance and the detection result of the detected coil mutual inductance. If the error does not meet the error requirement, the control variable of the PI controller is updated based on the error until the error meets the error requirement or the number of updates meets the update requirement, so as to obtain the final value of the control variable, which is the measurement result of the cladding tube thickness.

[0113] Furthermore, in a possible implementation of an embodiment of the present invention, in the parameter acquisition module 12, the cladding tube parameters include the cladding tube thickness, the inner and outer diameters of the cladding tube, and the electrical conductivity of the cladding tube; the receiving coil parameters include the number of coil turns, the inner and outer diameters of the coil, and the coil height; and the distance parameters include the lifting distance and the distance from the receiving coil to the axis of the cladding tube.

[0114] Furthermore, in a possible implementation of the embodiment of the present invention, in the calculation module 14 , the error meeting the error requirement means that the error at the current moment is less than or equal to a set error threshold.

[0115] Furthermore, in a possible implementation of an embodiment of the present invention, in the calculation module 14, the error between the calculation result of the coil mutual inductance and the detection result of the detected coil mutual inductance includes the current moment error and the cumulative error, and the control variable of the PI controller is updated based on the error, including: obtaining the updated control variable based on the product of the proportional coefficient of the PI controller and the current moment error, and the product of the integral coefficient of the PI controller and the cumulative error.

[0116] It should be noted that the above explanation of the embodiment of the nuclear fuel cladding wall thickness eddy current measurement method integrating the PI controller is also applicable to the nuclear fuel cladding wall thickness eddy current measurement system integrating the PI controller of this embodiment, and will not be repeated here.

[0117] In an embodiment of the present invention, an eddy current sensor is arranged outside the nuclear fuel cladding tube. The eddy current sensor includes a coaxial excitation coil and a receiving coil. The receiving coil is located near the cladding tube, and the axis of the receiving coil is perpendicular to the axis of the cladding tube. The method obtains parameter values ​​of multiple parameters such as cladding tube parameters, receiving coil parameters, and distance parameters between the receiving coil and the cladding tube, and obtains the detection results of the coil mutual inductance detected by the eddy current sensor; establishes a cladding tube eddy current analytical theoretical model, the input data of the cladding tube eddy current analytical theoretical model includes cladding tube parameters, receiving coil parameters and distance parameters, and outputs data is the coil mutual inductance; an initial value of the control variable of the PI controller is set, and the value of the cladding tube thickness in the cladding tube parameter is taken as the initial value of the control variable; based on the obtained parameter values ​​of multiple types of parameters, the calculation result of the coil mutual inductance is obtained by using the eddy current analytical theoretical model of the cladding tube; the error between the calculation result of the coil mutual inductance and the detection result of the detected coil mutual inductance is calculated; if the error does not meet the error requirement, the control variable of the PI controller is updated based on the error until the error meets the error requirement or the number of updates meets the update requirement, so as to obtain the final value of the control variable, and the final value of the control variable is the measurement result of the cladding tube thickness. In this case, eddy current sensors are placed on the exterior of the nuclear fuel cladding tubes. They induce eddy currents on and near the cladding tube surface to measure coil mutual inductance. A theoretical cladding tube eddy current analysis model is established, integrating multiple parameters, including cladding tube parameters, receiving coil parameters, and the distance between the receiving coil and the cladding tube. The cladding tube thickness, among the cladding tube parameters, is used as the initial value of the control variable of a PI controller. Based on the acquired values ​​of these multiple parameters, the cladding tube eddy current analysis model is used to calculate the coil mutual inductance. The PI controller's control variable is then updated based on the error between the calculated coil mutual inductance and the measured coil mutual inductance to obtain the final value of the control variable, thereby measuring the cladding tube thickness. This achieves high-precision cladding tube wall thickness measurement.

[0118] The method and system of the present invention are a contactless pipe wall thickness measurement method based on electromagnetic eddy current testing. A controller is used to iteratively update the wall thickness measurement value, achieving high-precision cladding tube wall thickness measurement. Specifically, a coaxial eddy current sensor with an excitation and a reception mechanism is designed. The sensor is located outside the cladding tube, with the sensor coil axis perpendicular to the cladding tube axis. Alternating current is passed through the excitation coil, inducing eddy currents on and near the cladding tube surface. An analytical theoretical model is established to calculate the change in sensor mutual inductance under a frequency sweep mode. A PI controller is set and control variables are initialized. The control variables are input as thickness values ​​into the analytical theoretical model to calculate the corresponding change in mutual inductance. The current and cumulative errors between the output of the analytical theoretical model and the measured result are calculated. The errors are input into the PI controller to update the control variable until the error falls below a threshold or the maximum number of iterations is reached. At this point, the controller outputs the cladding thickness measurement result as the control variable. The proposed method for measuring nuclear fuel ferrous cladding wall thickness with eddy currents, incorporating a PI controller, produces results consistent with experimental results. Accurate measurements are achieved through continuous iterative updates of the controller, demonstrating broad application prospects.

[0119] In order to implement the above embodiments, the present invention also proposes an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method provided by the above embodiments.

[0120] In order to implement the above embodiments, the present invention further provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the methods provided in the above embodiments.

[0121] In order to implement the above embodiments, the present invention further provides a computer program product, including a computer program, which implements the methods provided in the above embodiments when executed by a processor.

[0122] In the descriptions of the foregoing embodiments, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and features of different embodiments or examples, unless they are mutually inconsistent.

[0123] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0124] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present invention pertain.

[0125] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0126] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0127] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0128] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing module, or each unit may exist physically separately, or two or more units may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or in the form of software functional modules. If the integrated modules are implemented in the form of software functional modules and sold or used as independent products, they may also be stored in a computer-readable storage medium.

[0129] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and are not to be construed as limiting the present invention. Persons skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A nuclear fuel cladding wall thickness eddy current measurement method integrating a PI controller, characterized in that: An eddy current sensor is arranged outside the nuclear fuel cladding tube, the eddy current sensor including a coaxial excitation coil and a receiving coil, the receiving coil is located near the cladding tube, and the axis of the receiving coil is perpendicular to the axis of the cladding tube. The method includes: Obtain parameter values ​​of multiple parameters including cladding tube parameters, receiving coil parameters, and distance parameters between the receiving coil and the cladding tube, and obtain a detection result of the coil mutual inductance detected by the eddy current sensor; Establishing a theoretical model for eddy current analysis of a cladding tube, wherein input data of the theoretical model include cladding tube parameters, receiving coil parameters, and distance parameters, and output data is coil mutual inductance; Setting an initial value of a control variable of a PI controller, setting a value of the cladding tube thickness in the cladding tube parameter as the initial value of the control variable, and obtaining a calculation result of the coil mutual inductance using the cladding tube eddy current analytical theoretical model based on the obtained parameter values ​​of the multiple types of parameters; Calculate the error between the calculation result of the coil mutual inductance and the detection result of the detected coil mutual inductance. If the error does not meet the error requirement, update the control variable of the PI controller based on the error until the error meets the error requirement or the number of updates meets the update requirement, so as to obtain the final value of the control variable. The final value of the control variable is the measurement result of the cladding tube thickness.

2. The eddy current measurement method for nuclear fuel cladding wall thickness integrating PI controller according to claim 1 is characterized in that: The cladding tube parameters include the cladding tube thickness, the inner and outer diameters of the cladding tube, and the conductivity of the cladding tube; the receiving coil parameters include the number of coil turns, the inner and outer diameters of the coil, and the coil height; the distance parameters include the lifting distance and the distance from the receiving coil to the axis of the cladding tube.

3. The eddy current measurement method for nuclear fuel cladding wall thickness integrating PI controller according to claim 1, characterized in that: The error meeting the error requirement means that the error at the current moment is less than or equal to the set error threshold.

4. The eddy current measurement method for nuclear fuel cladding wall thickness integrating PI controller according to claim 1, characterized in that: The error between the calculated result of the coil mutual inductance and the detected result of the coil mutual inductance includes a current moment error and a cumulative error. The control variable of the PI controller is updated based on the error, including: obtaining an updated control variable based on the product of a proportional coefficient of the PI controller and the current moment error, and the product of an integral coefficient of the PI controller and the cumulative error.

5. A nuclear fuel cladding wall thickness eddy current measurement system integrated with a PI controller, characterized in that: include: The eddy current detection device includes an eddy current sensor, which is arranged outside the nuclear fuel cladding tube. The eddy current sensor includes a coaxial excitation coil and a receiving coil. The receiving coil is located near the cladding tube, and the axis of the receiving coil is perpendicular to the axis of the cladding tube. The eddy current sensor is used to obtain the detection result of the coil mutual inductance; A parameter acquisition module is used to obtain parameter values ​​of multiple parameters such as cladding tube parameters, receiving coil parameters, and distance parameters between the receiving coil and the cladding tube, and to obtain detection results of the coil mutual inductance detected by the eddy current sensor; A modeling module is used to establish a theoretical model of eddy current analysis of the cladding tube, wherein the input data of the theoretical model include cladding tube parameters, receiving coil parameters and distance parameters, and the output data is the coil mutual inductance; A calculation module is used to set an initial value of a control variable of a PI controller, take the value of the cladding tube thickness in the cladding tube parameter as the initial value of the control variable, obtain a calculation result of the coil mutual inductance based on the obtained parameter values ​​of multiple types of parameters using the eddy current analytical theoretical model of the cladding tube, calculate the error between the calculation result of the coil mutual inductance and the detection result of the detected coil mutual inductance, and if the error does not meet the error requirement, update the control variable of the PI controller based on the error until the error meets the error requirement or the number of updates meets the update requirement, so as to obtain a final value of the control variable, wherein the final value of the control variable is the measurement result of the cladding tube thickness.

6. The nuclear fuel cladding wall thickness eddy current measurement system integrated with a PI controller according to claim 5, characterized in that: In the parameter acquisition module, the cladding tube parameters include the cladding tube thickness, the inner and outer diameters of the cladding tube, and the conductivity of the cladding tube; the receiving coil parameters include the number of coil turns, the inner and outer diameters of the coil, and the coil height; the distance parameters include the lifting distance and the distance from the receiving coil to the axis of the cladding tube.

7. The nuclear fuel cladding wall thickness eddy current measurement system integrated with a PI controller according to claim 5, characterized in that: In the calculation module, the error meeting the error requirement means that the error at the current moment is less than or equal to a set error threshold.

8. The nuclear fuel cladding wall thickness eddy current measurement system integrated with a PI controller according to claim 5, characterized in that: In the calculation module, the error between the calculation result of the coil mutual inductance and the detection result of the detected coil mutual inductance includes a current moment error and a cumulative error, and the control variable of the PI controller is updated based on the error, including: obtaining the updated control variable based on the product of the proportional coefficient of the PI controller and the current moment error, and the product of the integral coefficient of the PI controller and the cumulative error.

9. An electronic device, characterized in that: include: a processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 1 to 4.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 4 when executed by a processor.

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