KR101724151B1 - Estimating method for impact position and mass of metal piece using ambiguity pattern recognition - Google Patents

Abstract

Disclosed is a method to estimate an impact position and the mass of metal foreign matters simultaneously by using ambiguity pattern recognition, performing an impact test using a steel ball with respect to a nuclear power plant equipment structure or a simulation structure, applying an ambiguity calculation result as pattern recognition to construct a database, and determining authenticity of a signal through pattern recognition after ambiguity calculation of an acquired alert signal when an impact signal of a metal foreign matter generated in a nuclear power plant equipment occurs normal operation of a nuclear power plant, and estimating a position and the mass of an impact simultaneously by using an impact distance. According to the present invention, by using a database server (130) and a computer including a central processing unit (122), the ambiguity calculation between alert signals detected by a vibration sensor installed in upper and lower steam generators (101) and a coolant pump (102) of a nuclear reactor (103) in the nuclear power plant equipment (100) of the Fig. 1 and data acquired in real time through a data acquisition system (100) is performed, and pattern recognition calculation between the alert signals and data constructed in the database server is performed, so the position and the mass of the impact of the metal foreign matter are able to be correctly and quickly estimated. The database is constructed by performing the impact test with the nuclear power plant equipment structure or the simulation structure (201) of the Fig. 2, and a steel ball impact test device, and then storing ambiguity calculation results in the database server (130) to be used. Moreover, a result of the position and the mass of the impact of the foreign matter estimated by applying a method of the present invention is able to understand a damageable region and effect during health diagnosis of the nuclear power plant equipment structure.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for simultaneously estimating an impact position and a mass of a metal foreign object using ambiguity pattern recognition,

More particularly, the present invention relates to a method of simultaneously estimating impact positions and masses of metal impurities using ambiguity pattern recognition of a nuclear power plant primary system, and more particularly, When a shock due to a metal foreign substance is generated in the reactor and the steam generator during normal operation after the impact test database is constructed by using the data acquisition system (DAQ System) The impact position of the metal impurity and the impact mass of the metal impurity can be estimated by comparing the obtained impulse vibration signal with the database constructed by the central arithmetic processing unit, Mass simultaneous estimation method.

1, the main apparatus 100 of the nuclear reactor system of the pressurized water reactor type is composed of a reactor, a steam generator, and a coolant pump. The main apparatus is a pressure boundary structure and is mostly a plate or shell type structure. These internal structures cause metal foreign substances in the interior due to repeated corrosion or relaxation shrinkage due to the flow of the coolant, or foreign substances such as metal are generated due to carelessness during maintenance.

These foreign substances flow through the flow path of the coolant pump and impact the inside of the structure. If an impact is applied to the structure, the structure may be damaged, and safety problems such as radioactive contamination of the secondary cooling water may occur.

Therefore, at nuclear power plants, a metal debris monitoring system is installed and operated in order to monitor these problems early and to perform structural health diagnosis. Currently, the surveillance diagnostic system is constructed to detect a shock signal by attaching a large number of vibration sensors to the upper and lower parts of the reactor, the steam generator, and the outer surface of the coolant pump body, which are the detectable parts of the nuclear device structure.

When an impulse vibration signal due to a foreign object is detected, the impulse signal is stored in real time, and the stored impulse signal is analyzed and diagnosed. The major diagnostic performance items are to estimate the impact location of the foreign object and estimate the mass of the foreign object to determine whether the structure is sound.

Therefore, the impact position and impact mass of the foreign object are used as information to distinguish the degree of damage and the vulnerable structure area by the impact, so it is the most important and the first thing to be selected in order to understand the integrity of the structure.

Conventionally, in order to estimate the impact position and the impact mass, the shock signal measured from the monitoring diagnostic system is analyzed by a computer including a separate central processing unit, memory, and input / output unit.

First, the impulse position of the foreign object is estimated by reading the occurrence time of each sensor by a monitor screen or printing output in the form of a graph based on the time axis and the vibration amplitude axis with respect to the impact signal, extracting the time difference of signal arrival, The impact position is estimated by applying a position estimation method such as the law. However, this method causes an error depending on the degree of readout of the reader. Particularly, there are cases where background noise (signal noise) is included in the impact signal or distortion due to the propagation characteristics of the impact signal is difficult to read. It is also impossible to judge whether the impulse signal is caused by a foreign matter impact signal due to the internal flow or by friction or thermal shock of the external structure.

In order to solve such a problem, there is a need for an advanced diagnosis method rather than a simple time graph reading method. A diagnostic method using a time-frequency analysis method is currently being developed to solve such a problem. This method utilizes the characteristic that the propagation speed of shock wave differs according to the frequency when the characteristic of the impulse signal by the metal foreign matter propagates along the structure at the impact point, and the dispersion characteristic of the signal occurs. Therefore, when the signal of the shock wave is computed in the central processing unit and the memory, and output to the three-dimensional graph of the time axis, the frequency axis and the vibration energy axis, the dispersion characteristic of the impact energy becomes clear in the case of the internal impact signal by the foreign substance, It is possible to judge whether or not.

Also, by using such a dispersion characteristic, the arrival time difference information of the impact signal measured by each sensor can be accurately extracted, and the impact position can be more clearly estimated. Therefore, a method of estimating the impact position using the time- Has been developed and utilized. In this method, the shock signals sensed by three or more vibration sensors are read out from the energy diagrams represented by the dispersion characteristics of the shock waves in the three-dimensional graph, and the dispersion diagrams of the shock waves are extracted. This method estimates the impact position of the foreign object by estimating the impact distance or applying the position estimation method of the trigonometric method or the circular intersection method.

However, the limitation of this method is that as the impact position of the foreign object moves away from the sensing sensor, the dispersion characteristic is lowered due to the distortion of the impact signal, which makes it difficult to extract the reading and dispersion diagram.

Therefore, it is necessary to develop a diagnostic method that can estimate the impact position without reading the arrival time difference according to the dispersion characteristics, while maintaining accurate judgment of whether or not the impact is caused by a metal foreign substance in the nuclear electric equipment.

The method of estimating the mass of a foreign object has been developed by an analytical technique based on the theoretical Hertz shock theory, a spectrum analysis technique of a foreign matter impact signal, or a time-frequency analysis technique. However, since all of these methods estimate the mass of the foreign object based on the data of the frequency of the vibration signal generated by the impact, accurate frequency information extraction of the shock wave is indispensable in order to accurately estimate the foreign substance mass. However, since the vibration signal includes not only the signal due to the impact of the foreign object but also the background noise generated by the attachment condition of the vibration sensor, the resonance component, and the coolant flow, it is difficult to extract the frequency data information of the pure shock wave. And it is necessary to develop analytical methods that can be used.

If the impact location and mass estimation technology is developed to overcome these problems, it will improve the reliability of the structural integrity diagnosis of nuclear power plants, and it will be possible to operate nuclear power plants with more safety by early action before a safety accident occurs.

KR 10-0662083 JP 2000019286 A JP 2001264151 A JP 12346681 A KR 10-0336064 KR 10-0798007

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, A method of simultaneous estimation of impact position and mass of a metal foreign object by using ambiguity pattern recognition that can determine the authenticity of a shock wave generated by a metal foreign object.

It is another object of the present invention to provide an edible data production method which is a pattern capable of estimating impact position and impact mass regardless of a distortion of an impact signal or an impact point by a pattern recognition method when an impact is caused by a metal foreign substance, And to provide a simultaneous estimation method of impact position and mass of a metal foreign object using ambiguity pattern recognition based on a database construction method.

According to another aspect of the present invention, there is provided a method for simultaneously estimating impact position and mass of a metal foreign object using ambiguity pattern recognition according to the present invention, A reference database construction step of applying shocks by setting various distances, acquiring vibration signals generated at impact, analyzing shock wave data propagated in the structure, and constructing a reference database based on the analyzed shock waves; A signal filtering step of filtering the noise signal by receiving the alarm signal data detected by the active nuclear device; The filtered alarm signal data is represented by the following equation:

An ambiguity computing step of computing an ambiguity by using the ambiguity; Extracting a result of the ambiguity calculation into a three-dimensional image file, or extracting feature vector factors by dividing a feature representing an image feature or a quadrant into four quadrants and dividing a specific region of each quadrant, , A comparison database construction step of constructing a comparison database by classifying by impact velocity and impact distance; And an estimation step of determining an impact position and an impact mass from the alarm signal data sensed through the reference database and the comparison database.

At this time, the analysis of the shock wave data is carried out by subjecting a simulated structure similar to the nuclear power equipment structure or the nuclear power equipment structure to a variety of impact masses, impact speeds and impact distances using a steel ball, The noise signal filter operation on the vibration signal is performed through the data, and the filtered data by the noise signal filter operation on the vibration signal through the experiment data is subjected to the ambiguity operation using the equation, And extracting the pattern identification data through the feature vector.

In the estimating step, the impact position and the impact mass are estimated through comparison of the data of the reference database and the pattern recognition operation, and the pattern recognition operation is performed using a hidden markov model (HMM), an artificial neural network (ANN) And SPC (Statistical Processing Control).

The method may further include a monitoring step of monitoring a result calculated through the estimation step through a screen output device.

As described above, according to the present invention, it is possible to quickly and accurately determine the authenticity of an impulse signal caused by a metallic foreign substance in a nuclear power plant, and to make an objective judgment regardless of the capability of a judge.

In addition, when a database is built in advance by a shock test and the pattern recognition calculation process is performed when an impact signal is generated, when the impact position of the foreign object is estimated, the arrival time difference of the impact signal acquired by each vibration sensor and the extraction speed It is possible to extract the impact distance information up to the impact position in each sensor without performing the analysis, thereby making it more accurate and easy to analyze.

In addition, when the impact mass is estimated through the pattern recognition calculation method using the above-described database, it is possible to estimate the impact mass more accurately and easily by only the pattern recognition calculation process without the process for extracting the mass index required in the prior art.

FIG. 1 is a schematic diagram showing an operation processor and a processing procedure for acquiring a nuclear foreign material alarm signal and diagnosing an alarm signal, to which the technical method of the present invention can be applied.
FIG. 2 is a schematic diagram showing a process and construction of a steel ball impact test data for building a database for pattern recognition calculation.
3 is a schematic diagram illustrating a process of receiving an alarm signal generated from a nuclear power device and estimating an impact position and mass by pattern recognition.
FIG. 4 is a schematic view showing a procedure for constructing a steel ball impact test database for producing a patterned food data.
5 shows an example of a graph outputting the result of the ambiguity calculation process for the impulse signal of the metal foreign substance.
FIG. 6 is a graph showing an example of a result of an ambulance operation processing result of steel ball impact test data according to an impact distance in a nuclear power plant structure.
FIG. 7 shows an example of a graph outputting the results of the ambulatory operation processing on the steel ball impact test data according to the impact mass and the impact velocity in the nuclear power plant structure.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

The terms including ordinal, such as second, first, etc., may be used to describe various elements, but the elements are not limited to these terms.

The terms used herein are used only for the purpose of distinguishing one element from another. For example, without departing from the scope of the present invention, the second component may be referred to as a first component, and similarly, the first component may also be referred to as a second component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

In the present invention, impact masses, impact speeds, and impact distances are variously set in a simulated structure similar to a structure of a nuclear power system 100 or a nuclear power system 100, shocks are applied thereto, A reference database construction step of analyzing the shock wave data propagated in the structure and constructing a reference database based on the analysis; A signal filtering step of filtering the noise signal by receiving the alarm signal data sensed by the active nuclear device 100; The filtered alarm signal data is represented by the following equation:

An ambiguity computing step of computing an ambiguity by using the ambiguity; Extracting a result of the ambiguity calculation into a three-dimensional image file, or extracting feature vector factors by dividing a feature representing an image feature or a quadrant into four quadrants and dividing a specific region of each quadrant, , A comparison database construction step of constructing a comparison database by classifying by impact velocity and impact distance; And an estimation step of determining an impact position and an impact mass from the alarm signal data sensed through the reference database and the comparison database.

At this time, the analysis of the shock wave data is carried out by setting various impact masses, impact speeds and impact distances using a steel ball for a simulated structure similar to a nuclear power system 100 structure or a nuclear power system 100 structure, A noise signal filter operation is performed on the vibration signal through the experiment data, and the filtered data by the noise signal filter operation on the vibration signal is subjected to the ambiguity operation through the equation Extracts a feature vector, and extracts pattern-identifying data through the feature vector.

In the estimating step, the impact position and the impact mass are estimated through comparison of the data of the reference database and the pattern recognition operation, and the pattern recognition operation is performed using a hidden markov model (HMM), an artificial neural network (ANN) And SPC (Statistical Processing Control).

The method further includes a monitoring step of monitoring a result calculated through the estimation step through a screen output device.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic view showing an operation processor and a processing procedure for acquiring a warning signal of a nuclear foreign material alarm signal and for diagnosing an alarm signal to which the technical method of the present invention can be applied. FIG. 3 is a schematic view illustrating a process of receiving an alarm signal generated from a nuclear power plant and estimating an impact position and a mass by pattern recognition, FIG. FIG. 5 is a graph showing an example of outputting the result of the ambiguity calculation processing for the impact signal of a metal foreign substance, FIG. 6 is a graph showing an example of a steel ball impact test An example of a graph showing the result of the ambiguity operation processing on data is shown , Figure 7 shows a graph example in figures aembi eoti outputs the arithmetic processing result of the steel ball impact test data in accordance with the impact mass and the impact velocity on the nuclear power plant unit construction.

An alarm signal sensed by a vibration sensor installed in the upper and lower portions of the reactor 103 and the steam generator 101 and the coolant pump 102 in the nuclear reactor 100 of FIG. 1 is acquired and stored in the data acquisition system 110, The alarm signal obtained by using the central processing unit 122 and the computer composed of the network interface 121, the RAM memory 124 and the screen output unit 125 and the database server 130 is transmitted via the network interface 121 Receives the pattern recognition data from the database server 130 and stores the pattern recognition data in the RAM memory 123, and compares and analyzes the feature vectors with each other .

The data acquisition system 110 may use a monitoring diagnostic system installed in a nuclear power plant or various measurement systems capable of acquiring vibration signals in general.

를 절대시간 t에 대한 퓨리에 변환한 것이다. 여기에서 τ는 시간 지연 변수이고,

는

과 τ축으로 이루어진 앰비규어티 함수를 나타낸다.The ambiguity calculation method enables the vibration signal of the shock wave to be calculated using Equation (1). The ambiguity function of Equation (1) is a time-dependent autocorrelation function

Is the Fourier transform of the absolute time t. Where τ is a time delay variable,

The

And the τ-axis.

축과 τ축의 원점을 중심으로 4개의 사분면으로 나눌 수 있으며, 원전기기 구조물에 이물질의 충격으로 발생하는 충격파의 경우 주요 신호 성분이 제2사분면(520)과 제4사분면(540)에 분포하고 있음을 알 수 있다. 따라서 패턴인식을 위한 특징벡터 추출은 제2사분면(520)과 제4사분면(540)의 그룹과 제1사분면(510)과 제3사분면(530)을 그룹으로 구분하여 추출하여 비교할 수 있도록 한다.5 shows an example of outputting a result of arithmetic processing of a shock wave generated by impacting a steel ball on a flat plate and a shell structure using an ambi-feature function. The ambiguity calculation result graph 500 includes

Axis and the origin of the τ axis, and the main signal components are distributed in the second quadrant (520) and the fourth quadrant (540) in the case of the shock wave generated by the impact of foreign matter on the nuclear device structure . Accordingly, the feature vector extraction for pattern recognition can extract and compare the groups of the second and fourth quadrants 520 and 540, the first quadrant 510 and the third quadrant 530 by grouping.

Referring to FIGS. 2 and 4, the present invention may be applied to a nuclear power plant structure 100 or a quasi-simulated structure 200 for constructing a pattern recognition database, Attaches the vibration sensor 204 to the surface of the structure to acquire a vibration signal, and transmits the shock wave data propagated in the structure to the database server to construct a database.

In the analysis of the shock wave data, the central processing unit 222 receives the ball impact test data (400), performs the noise signal filter operation (401) on the vibration signal, and carries out the ambi- After extracting the feature vector, it extracts pattern recognition data and builds the database.

The feature vector extraction method of the result of ambiguity calculation is to extract the ambiguity result as a three-dimensional image file, or to divide the feature into four quadrants, The factors are extracted, and the experimental steel balls are classified by mass, impact velocity, and impact distance so that they can be constructed as a database.

3, the central processing unit 222 receives n alarm signal data (300), pre-processes the noise signal filter operation (401), and outputs the filtered data as an ambiance The feature vector is extracted, and the impact position and the impact mass are estimated (306) through the comparison of the data of the database 305 and the pattern recognition operation (304).

The pattern recognition operation can be performed by applying algorithms such as HMM (Hidden Markov Model), ANN (Artificial Neural Network), Fuzzy logic, SPC (Statistical Processing Control), and the like. It is possible to input and receive data from the database constructed from the data of the test results.

축에서

축 방향으로 신호 성분이 이동하는 것을 알 수 있다.The example shown in FIG. 6 shows the result of performing the ambiguity operation by dividing the impact distance by 0.3 m, 0.9 m, 1.8 m, and 2.7 m while maintaining the impact mass and the impact velocity constant. Regardless of the condition, all the results can be seen in the second and fourth quadrants including the major signal, and as the impact distance increases

On axis

It can be seen that the signal component moves in the axial direction.

The example shown in FIG. 7 shows a result (700) of the ambiguity calculation performed by dividing the impact velocity by 0.5 m / s, 1.0 m / s, and 2.0 m / s while keeping the impact mass and impact distance constant . Similar to the above results, it can be seen that the main signals are distributed in the second and fourth quadrants.

Also, it shows the result (710) of the ambiguity calculation by classifying the impact masses into 100grams, 140grams, and 180grams while keeping the impact velocity and the impact distance constant. Similar to the above results, it can be seen that the main signals are distributed in the second and fourth quadrants. These features can be extracted as feature vectors and constructed as a database.

As shown in FIGS. 1 and 3, when the impulse position and the impact mass are estimated when the foreign matter alarm signal is generated in the nuclear power unit structure according to the method of the present invention, information can be obtained more accurately and quickly than in the prior art .

100: nuclear equipment
101: Steam generator
102: coolant pump
103: Reactor
110: Surveillance diagnostic system
120: arithmetic processing unit
200: Steel ball impact test system
201: Nuclear equipment structure
202: Steel ball impact test support
203: Steel rod for impact test
204: Vibration sensor
205: Flexible wire for steel ball support
210: Surveillance diagnostic system
220: arithmetic processing unit

Claims (4)

Impact mass, impact velocity and impact distance are variously set for a nuclear structure or a simulated structure similar to the nuclear structure, and the vibration signal generated at impact is acquired to analyze the shock wave data propagated in the structure A reference database building step of building a reference database on the basis thereof;
A signal filtering step of filtering the noise signal by receiving the alarm signal data detected by the active nuclear device;
The filtered alarm signal data is represented by the following equation:

(here,

: Time dependent autocorrelation function
t: absolute time
τ: time delay variable

:

And the τ-axis is an ambiguity function)
An ambiguity computing step of computing an ambiguity by using the ambiguity;
Extracting a result of the ambiguity calculation into a three-dimensional image file, or extracting feature vector factors by dividing a feature representing an image feature or a quadrant into four quadrants and dividing a specific region of each quadrant, , A comparison database construction step of constructing a comparison database by classifying by impact velocity and impact distance; And
And an estimation step of determining an impact position and an impact mass from the alarm signal data sensed through the reference database and the comparison database. A method for simultaneously estimating impact position and mass of a metal foreign object using ambiguity pattern recognition .
The method of claim 1, wherein the analysis of the shock wave data comprises:
Impact mass, impact velocity and impact distance were set variously using a steel ball for a nuclear equipment structure or a simulated structure similar to the nuclear equipment structure,
Performing a noise signal filter operation on the vibration signal through the experimental data,
Extracting a feature vector by performing an ambiguity operation on the data filtered by the noise signal filter operation on the vibration signal through the equation,
And extracting pattern recognition data through the feature vector. The method of simultaneously estimating impact position and mass of a metal foreign object using ambiguity pattern recognition.
2. The method according to claim 1,
Estimating an impact position and an impact mass through comparison of pattern recognition operation with data of the reference database,
Wherein the pattern recognition calculation is performed using at least any one of an algorithm of HMM (Hidden Markov Model), ANN (Artificial Neural Network), Fuzzy logic and SPC (Statistical Processing Control) Simultaneous estimation of impact location and mass.
4. The method according to any one of claims 1 to 3,
And a monitoring step of monitoring a result calculated through the estimation step through a screen output device. The method of simultaneously estimating impact position and mass of a metal foreign object using ambiguity pattern recognition.

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