JP7427580B2 - Coolant pressure coefficient measurement method, coolant pressure coefficient measurement system and program - Google Patents

Description

The present disclosure relates to a coolant pressure coefficient measuring method, a coolant pressure coefficient measuring system, and a program.

Coolant pressure coefficient and moderator temperature coefficient are used as indicators of the safety of nuclear power plants. Patent Document 1 discloses a method of measuring the moderator temperature coefficient of an operating PWR nuclear power plant and the void coefficient of an operating BWR (Boiling Water Reactor) nuclear power plant using a noise analysis method.

Japanese Patent Application Publication No. 2008-45972

Data on the coolant pressure and reactivity of an operating BWR type nuclear power plant contains many noise components, and it is desired to measure the coolant pressure coefficient.

The present disclosure provides a coolant pressure coefficient measuring method, a coolant pressure coefficient measuring system, and a program that can solve the above problems.

A method for measuring a coolant pressure coefficient of the present disclosure includes the steps of acquiring time-series coolant pressure measurement data and reactivity measurement data measured during operation of a nuclear power plant; Executing a process of extracting a principal component from each piece of reactivity measurement data; and creating reactivity evaluation data that approximates the principal component of the reactivity measurement data by combining a plurality of functions. a step of creating evaluation data of the coolant pressure that approximates the main component of the measured data of the coolant pressure by a combination of the plurality of functions; a step of executing a noise analysis method using the evaluation data; A function is one function group, and in the step of creating the reactivity evaluation data, the functions included in the function group are combined to create a first one that approximates the main component of the reactivity measurement data. In the step of creating a function and creating the coolant pressure evaluation data, the functions included in the function group are combined to create a second function that approximates the main component of the coolant pressure measurement data.

The coolant pressure coefficient measurement system of the present disclosure includes an acquisition unit that acquires time-series coolant pressure measurement data and reactivity measurement data measured during operation of a nuclear power plant; a principal component extraction unit that executes a process of extracting a principal component for each of the reactivity measurement data; and a principal component extraction unit that extracts a principal component from each of the reactivity measurement data; a reconstruction unit that creates evaluation data of the coolant pressure that approximates the main component of the measured data of the coolant pressure by a combination of the plurality of functions, the evaluation data of the coolant pressure; a noise analysis method execution unit that executes a noise analysis method using reactivity evaluation data , and the plurality of functions used to create the reactivity evaluation data and the coolant pressure evaluation data. The plurality of functions used to create the function group is one function group, and the reconstruction unit combines the functions included in the function group to generate a first function that approximates the main component of the reactivity measurement data. A second function that approximates the main component of the coolant pressure measurement data is created by combining the functions included in the function group.

The program of the present disclosure includes the steps of: acquiring time-series coolant pressure measurement data and reactivity measurement data measured during operation of a nuclear power plant in a computer; a step of executing a process of extracting a principal component from each of the measurement data of the reactivity, and a step of creating evaluation data of the reactivity that approximates the principal component of the measurement data of the reactivity by a combination of a plurality of functions. , creating evaluation data of the coolant pressure that approximates the main component of the measured data of the coolant pressure by a combination of the plurality of functions; the evaluation data of the coolant pressure; and the evaluation data of the reactivity. and executing a noise analysis method using the plurality of functions used to create the evaluation data of the reactivity, and the plurality of functions used to create the evaluation data of the coolant pressure. is one function group, and in the step of creating the reactivity evaluation data, the functions included in the function group are combined to create a first function that approximates the main component of the reactivity measurement data. In the step of creating the coolant pressure evaluation data, a process is performed to create a second function that approximates the main component of the coolant pressure measurement data by combining functions included in the function group. let

According to the above-described coolant pressure coefficient measuring method, coolant pressure coefficient measuring system, and program, the coolant pressure coefficient can be measured based on the measured data of the coolant pressure and reactivity, which have many noise components.

FIG. 1 is a block diagram illustrating an example of a coolant pressure coefficient measurement system according to an embodiment. FIG. 2 is a diagram showing an overview of a method for measuring a coolant pressure coefficient according to an embodiment. It is a figure which shows an example of a coolant pressure signal and a reactivity signal. FIG. 3 is a first diagram showing an example of a signal analysis result according to the embodiment. FIG. 7 is a second diagram showing an example of a signal analysis result according to the embodiment. FIG. 3 is a diagram illustrating an example of a signal after reconstruction processing according to the embodiment. It is a figure which shows an example of the processing result by the conventional noise analysis method. It is a figure showing an example of a processing result by a method of measuring a coolant pressure coefficient of an embodiment. It is a flowchart which shows an example of a coolant pressure coefficient measurement process of an embodiment. 1 is a diagram illustrating an example of a hardware configuration of a coolant pressure coefficient measurement system according to an embodiment.

<Embodiment>
Hereinafter, the coolant pressure coefficient measuring method of the present disclosure will be described with reference to FIGS. 1 to 9.
(System configuration)
FIG. 1 is a block diagram showing an example of a coolant pressure coefficient measurement system according to an embodiment.
The coolant pressure coefficient measurement system 1 obtains measured values of coolant pressure and neutron flux from an operating BWR type nuclear power plant, and calculates a coolant pressure coefficient.

The coolant pressure coefficient measurement system 1 is communicably connected to the nuclear power plant 2, acquires the coolant pressure and neutron flux from the nuclear power plant 2 in rated operation, and measures the coolant pressure coefficient.
The nuclear power plant 2 is provided with a pressure sensor and a neutron detector. The pressure sensor measures the pressure of the reactor coolant and transmits the measured pressure to the coolant pressure coefficient measurement system 1 . The neutron detector measures the neutron flux of the nuclear reactor and transmits the measured neutron flux to the coolant pressure coefficient measurement system 1 .

The coolant pressure coefficient measuring system 1 includes a reactivity measuring device 3 and a measuring device 10. The reactivity measuring device 3 and the measuring device 10 are configured by one or more computers such as a PC or a server device.

The reactivity measuring device 3 acquires the neutron flux measured in the nuclear power plant 2 and calculates the reactivity of the reactor core. Reactivity is an index for determining whether something is critical or subcritical, and corresponds to the change in neutron flux over time. The reactivity measuring device 3 calculates the reactivity using, for example, a one-point reactor dynamic characteristic equation.The reactivity measuring device 3 outputs the reactivity to the measuring device 10.

The measuring device 10 includes a signal acquisition section 11, an input reception section 12, a singular value decomposition execution section 13, a signal analysis section 14, a signal reconstruction section 15, a noise analysis method execution section 16, and a storage section 17. , and an output section 18.
The signal acquisition unit 11 acquires a signal of the coolant pressure measurement value (referred to as a coolant pressure signal) and a signal of the reactivity calculated by the reactivity measuring device 3 (referred to as a reactivity signal). . These signals are time-series data measured from time to time or calculated based on measurement values measured from time to time.
The input receiving unit 12 receives setting input for a function set consisting of a plurality of functions.
The singular value decomposition execution unit 13 performs singular value decomposition on each of the coolant pressure signal and the reactivity signal, and extracts the principal component of each signal.

The signal analysis unit 14 analyzes the correlation between the coolant pressure signal and the reactivity signal after singular value decomposition. This analysis is performed for the purpose of selecting a set of functions.
The signal reconstruction unit 15 reconstructs the coolant pressure signal by combining function sets. The reconstructed coolant pressure signal is referred to as a coolant pressure signal (re). The signal reconstruction unit 15 reconstructs the reactivity signal by combining function sets. The reconstructed reactivity signal is referred to as a reactivity signal (re).
The noise analysis method execution unit 16 uses the coolant pressure signal (re) and the reactivity signal (re) to execute a noise analysis method that is generally implemented for PWR nuclear power plants.
The storage unit 17 stores information for measuring the coolant pressure coefficient, such as the coolant pressure signal, reactivity signal, set function set, coolant pressure signal (re), and reactivity signal (re) acquired by the signal acquisition unit 11. Memorize necessary information.
The output unit 18 outputs the measured coolant pressure coefficient to a display device, an electronic file, or the like.

(Overall process flow)
FIG. 2 is a diagram illustrating an overview of a method for measuring a coolant pressure coefficient according to an embodiment.
The coolant pressure coefficient measuring method of this embodiment is roughly divided into a first evaluation flow and a second evaluation flow. In the first evaluation flow, the singular value decomposition execution unit 13 performs singular value decomposition on each of the reactivity signal (ρ) and the coolant pressure signal (p) to extract principal components. Next, the signal analysis unit 14 analyzes the signal generated by extracting the principal component from the reactivity signal (ρ) and the signal generated by extracting the principal component from the coolant pressure signal (p). For this analysis result, the analyst sets a function set (function 1, function 2, function 3, . . . ). Then, the signal reconstruction unit 15 applies the function set to the principal component of each signal, and expands the principal component of each signal using the function set. In other words, by combining function sets, the main components of each signal are extracted and the resulting signal is reproduced (signal reconstruction). Through the above first evaluation flow, the noise of the reactivity signal (ρ) is removed, the reactivity signal (re)(ρ') is generated, the noise of the coolant pressure signal (p) is removed, and the coolant pressure signal (p) is removed. Generate a pressure signal (re)(p').

Next, a second evaluation flow is performed. The process itself of the second evaluation flow is similar to the process applied to a PWR type nuclear power plant. However, in the second evaluation flow, instead of using the reactivity signal (ρ) and the coolant pressure signal, the reactivity signal (re) (ρ′) and the coolant pressure signal obtained by implementing the first evaluation flow are used. A pressure signal (re) (p') is used. First, the noise analysis method execution unit 16 performs fast Fourier transform on each of the coolant pressure signal (re) (ρ') and the reactivity signal (re) (p'), and triangulates each signal (re). Convert to a combination of functions. Then, the noise analysis method execution unit 16 calculates the intensity of the signal component for each frequency for each of the reactivity signal (re) (ρ') and the coolant pressure signal (re) (p') after the fast Fourier transform. Calculate. As a result, the relationship between frequency and signal intensity can be obtained for the reactivity signal (re) (ρ') after fast Fourier transform and the coolant pressure signal (re) (p') after fast Fourier transform (respectively, the graph 201, graph 202). Next, the noise analysis method execution unit 16 evaluates the correlation based on the signal strength of the two signals for each frequency and the coolant pressure coefficient (=ρ'/p') (graph 203), and Calculate the final coolant pressure coefficient by averaging the coolant pressure coefficients that have a high value.

(Function set settings)
In this embodiment, the reactivity signal and the coolant pressure signal are reconstructed by a combination of function sets to obtain the reactivity signal (re) and the coolant pressure signal (re). This makes it possible to measure the coolant pressure coefficient of a BWR type nuclear power plant, which has been difficult due to the large number of noise components. FIG. 3 shows an example of a coolant pressure signal and a reactivity signal measured during rated operation of a BWR type nuclear power plant. Graph 31 is the coolant pressure signal, and graph 32 is the reactivity signal.

Next, with reference to FIGS. 4 and 5, a description will be given of how to select a function set in order to accurately reproduce the reactivity signal and coolant pressure signal after singular value decomposition. 4 and 5 are a first diagram and a second diagram, respectively, showing an example of the signal analysis results according to the embodiment.

The signal analysis unit 14 calculates the strength of the signal component for each frequency by performing the same processing as that included in the conventional noise analysis method, that is, fast Fourier transform, to select the function set. A process of calculating the correlation between two signals is performed. This is called the noise analysis method (conventional version). Fast Fourier transform is a process that is performed on the number of data that is 2 to the nth power. For this reason, for example, even if a reactivity signal consisting of 300 points (time series data of reactivity measured at 300 measurement times) is obtained, only 256 (=2 ⁸ ) measurement values are used. It will be processed. In other words, the noise analysis method (conventional version) extracts and processes a limited number of data from the reactivity signal and coolant pressure signal. In contrast to this conventional method, the present embodiment performs more precise analysis by increasing the number of data to be processed and increasing the number of processing times to obtain more processing results. For example, if a reactivity signal consisting of 300 points from t to t+299 is obtained, 45 measurement value groups from t to t+255, measurement value groups from t+1 to t+256, ..., measurement value groups from t+44 to t+299 are obtained. Create a reactivity signal. Then, fast Fourier transform is performed on each of the 45 generated reactivity signals. Furthermore, 45 coolant pressure signals are similarly created for the coolant pressure signals consisting of 300 points, and fast Fourier transform is performed on the coolant pressure signals. Then, the correlation between the reactivity signal and the coolant pressure signal of the corresponding measurement value group (256 measurement value group for the same period) is analyzed. In this way, 45 processing results (correlation) are obtained, and the correlation between the reactivity signal and the coolant pressure signal can be analyzed more precisely. This method is called the noise analysis method (improved version). Furthermore, the noise analysis method (improved version) also analyzes phase shifts, which is not performed in the noise analysis method (conventional version).

First, refer to FIG. 4. FIG. 4 is a graph plotting the correlation values obtained by the noise analysis method (conventional version) and the correlation values obtained by the noise analysis method (improved version). The vertical axis of the graph shown in FIG. 4 is the correlation value between coolant pressure and reactivity, and the horizontal axis is frequency. As shown in the figure, in the analysis results obtained by the noise analysis method (improved version), as shown in box 41, the correlation value of the low frequency component is high, and as shown in box 42, the correlation value around 4 Hz is as follows. The result was that it was high. In this way, by using the noise analysis method (improved version), it is possible to analyze trends that cannot be fully grasped using the noise analysis method (conventional version). Based on the results of this analysis, an analyst selects a function set. It is estimated that this includes a quadratic function. Also, based on the high correlation value around 4 Hz, the analyst estimates that the set of functions that reconstruct the reactivity signal and the coolant pressure signal include trigonometric functions.

Refer now to FIG. Figure 5 shows a correlation analysis that takes into account the phase shift (time delay) between the reactivity signal and the coolant pressure signal in the process of analyzing the correlation using the noise analysis method (improved version). be. This analysis is made possible by analysis that includes the imaginary component of the data after fast Fourier transform, which is not handled by the noise analysis method (conventional version). The vertical axis of the graph shown in FIG. 5 is the correlation value between coolant pressure and reactivity, and the horizontal axis is the phase shift angle. Referring to the phase shift analysis results, as shown in box 51, a high correlation value can be confirmed when the phase shift is around 90°, and as shown in box 52, a high correlation value can be confirmed when the phase shift is around 270°. Based on the analysis result of the phase shift in which peaks appear at 90° and 270°, the analyst estimates that the previously estimated trigonometric function is a sine function, for example. For example, if high correlation values can be confirmed near phase shifts of 0° and 180°, the analyst estimates that the trigonometric function is a cosine function. Further, from the overall trend of the graphs 31 and 32 shown in FIG. 3, the analyst estimates that the function set includes linear functions×trigonometric functions.

In this way, the analyst selects a function that is considered suitable from the characteristics of the target signal, based on the analysis results of the noise analysis method (improved version). In the case of the coolant pressure and reactivity signals illustrated in Figure 3, the analyst can determine that the overall characteristics of both signals are constant, or varying linearly in time, with periodic fluctuations. For example, we estimate the contents of the following function set.
1) Linear function f1(t)=a×t (t is time)
2) Quadratic function f2(t)=b× ^t2
3) Periodic function (trigonometric function) f3(t)=c×sin(ωn×t)
For ωn, n sets with different frequencies are prepared. For example, as shown in Figure 4, low-frequency components are predominant in the preliminary analysis, so we use several hundred (for example, n = 400) of the lowest low-frequency components that can be expressed from the length of the available data set. .
4) Combination of linear function and periodic function
f4(t)=d×t×e×sin(ωn×t)
Regarding ωn, several hundred low frequency components are selected as in 3).
5) Constant term C (constant) C may be 0.
For example, when setting 400 frequencies for the sine function, a total of 803 functions 1) to 5) are selected as the function set.

The function set setting process (selection of the function group included in the function set) may be performed each time the coolant pressure coefficient is measured, or the function group once selected may be used as is. The above 1) to 5) were selected based on the characteristics of the coolant pressure signal and reactivity signal illustrated in Fig. 3, but since they are general functions, they are not very unique. It is believed that the same set of functions can be used as long as the signal is not measured. After setting the function set, the analyst inputs the function set to the measuring device 10. The input receiving unit 12 receives the set function set and registers it in the storage unit 17.

(Signal reconstruction)
Once the function set is set, the signal reconstruction unit 15 calculates a signal that approximates the coolant pressure signal after singular value decomposition and a signal that approximates the reactivity signal after singular value decomposition by expanding the function set. do. As a simple example, the function set includes one linear function, one quadratic function, two trigonometric functions, one combination of a linear function and a periodic function, and a constant C of 0. A function F(t) obtained by expanding the function set is expressed as the following equation (1).

F(t)=a1×t+b1×t ² +c1×sin(ωn1×t)+
c2×sin(ωn2×t)+d1×t×e1×sin(ωn×t)...(1)

The signal reconstruction unit 15 performs curve fitting of the target signal and equation (1) using the least square method or the like, and determines coefficients a1, b1, c1, c2, d1, and e1 of equation (1). . The signal reconstruction unit 15 determines coefficients a1, b1, c1, c2, d1, and e1 for the reactivity signal. Further, the signal reconstruction unit 15 separately determines coefficients a1, b1, c1, c2, d1, and e1 for the coolant pressure signal. The signal reconstruction unit 15 applies the values of coefficients a1, b1, c1, c2, d1, and e1 determined for the reactivity signal to equation (1) to generate a function that approximates the reactivity signal after singular value decomposition. Create F1(t). Giving t the same time as the reactivity signal after singular value decomposition is called reconstructing the reactivity signal after singular value decomposition. The signal reconstruction unit 15 calculates a reactivity signal (re) by reconstructing the reactivity signal. Similarly, the signal reconstruction unit 15 applies the values of the coefficients a1, b1, c1, c2, d1, and e1 determined for the coolant pressure signal to equation (1) to generate the coolant pressure signal after singular value decomposition. Create a function F2(t) that approximates , reconstruct the coolant pressure signal using the function F2(t), and calculate the coolant pressure signal (re).

FIG. 6 shows a reactivity signal (re) and a coolant pressure signal (re) reconstructed by the signal reconstruction unit 15 using an actual function set (for example, a group of 803 functions). Similar to FIG. 3, graph 31 is the coolant pressure signal and graph 32 is the reactivity signal. Graph 61 is the coolant pressure signal (re), and graph 62 is the reactivity signal (re).

(Calculation of coolant pressure coefficient)
The noise analysis method execution unit 16 executes a noise analysis method generally used in PWR type nuclear power plants on the reactivity signal (re) and the coolant pressure signal (re), and calculates the coolant pressure coefficient of the BWR type nuclear power plant. Calculate. An example of the coolant pressure coefficient calculated based on the reactivity signal (re) and the coolant pressure signal (re) is shown in FIG. 7B. For comparison, the results of a noise analysis method performed using the same coolant pressure and reactivity signals before reconstruction are shown in FIG. 7A. The vertical axis of the graphs in FIGS. 7A and 7B is the coolant pressure coefficient, and the horizontal axis is the correlation value between the coolant pressure and the reactivity. The correlation value is 1.0 when the correlation between the coolant pressure and the reactivity completely matches. Referring to FIG. 7A, whether it is a simple average of the coolant pressure coefficient for each frequency or a value calculated by weighting the coolant pressure coefficient for each frequency with a correlation value, the correlation value is generally low; There are very few effective components (correlation value of 0.4 or more). In order to see the correlation between coolant pressure and reactivity, out of the data in which coolant pressure and reactivity are broken down by frequency, data for frequencies with a high correlation value of signal strength is used to calculate the coolant pressure coefficient. It will be done. Data from which only correlation values such as those shown in FIG. 7A can be obtained are not suitable for calculating the coolant pressure coefficient.

On the other hand, referring to FIG. 7B, there is a frequency at which a relatively high correlation value of about 0.7 is obtained between the reactivity signal (Re) and the coolant pressure signal (Re). In this example, the noise analysis method execution unit 16 uses, for example, data of a frequency where the correlation value is a predetermined value (for example, 0.4 or more) as a coolant pressure signal (re) and a reactivity signal signal (re). are extracted from the data obtained by fast Fourier transform, and the signal strength of the reactivity signal divided by the signal strength of the coolant pressure signal at each frequency is calculated, and their average value is calculated. This average value is the coolant pressure coefficient. With the method of this embodiment, as shown in FIGS. 7A and 7B, it is possible to increase the effective component of the signal compared to the conventional noise analysis method that uses a coolant pressure signal and a reactivity signal that are not reconstructed. , it is possible to calculate a highly reliable coolant pressure coefficient. In addition, in a BWR type nuclear power plant, the design value of the coolant pressure coefficient is calculated at the time of plant design. It has been confirmed that the coolant pressure coefficient calculated by the coolant pressure coefficient measuring method of this embodiment is the same value as the design value of the coolant pressure coefficient.

(motion)
Next, the processing flow of the coolant pressure coefficient measuring system will be explained.
FIG. 8 is a flowchart illustrating an example of the coolant pressure coefficient measurement process according to the embodiment.
The signal acquisition unit 11 continuously acquires a reactivity signal and a coolant pressure signal from the nuclear power plant 2 in operation (step S1), and records each signal in the storage unit 17. The analyst performs an operation to instruct the measuring device 10 to start the process of measuring the coolant pressure coefficient. Then, the singular value decomposition execution unit 13 executes singular value decomposition (step S2). The singular value decomposition execution unit 13 reads out the reactivity signal and the coolant pressure signal measured during the same time period from the storage unit 17. The singular value decomposition execution unit 13 performs singular value decomposition on the read reactivity signal and extracts the main component of the signal. The singular value decomposition execution unit 13 extracts, for example, about 10 principal components. Similarly, the singular value decomposition execution unit 13 performs singular value decomposition on the read coolant pressure signal and extracts the main component of the signal. The principal components are extracted from the reactivity signal and the coolant pressure signal, and the reactivity signal (referred to as the principal component of the reactivity signal) is composed of the extracted principal components and the coolant is composed of the extracted principal components. In order to perform subsequent processing such as correlation analysis and reconstruction on the pressure signal (referred to as the main component of the coolant pressure signal), the original reactivity signal and coolant pressure signal, which have large noise components, are The processing is easier and the accuracy is improved compared to performing similar processing on the target.

Next, the signal analysis unit 14 determines whether or not to set a function set (step S3). For example, the analyst inputs into the measurement device 10 whether or not to set a function set. The signal analysis unit 14 determines whether or not to set a function set based on this input. Alternatively, the signal analysis unit 14 determines not to set the function set if the function set has already been set (if the function set has already been registered in the storage unit 17), and if the function set has not yet been set. It is determined that the function set is set. If it is determined that a function set is not to be set (step S3; No), the process proceeds to step S6.

If it is determined that a function set is to be set (step S3; Yes), the signal analysis unit 14 executes the noise analysis method (improved version) (step S4). In other words, the signal analysis unit 14 increases the number of data and the number of processes, performs fast Fourier transform on the reactivity signal from which only the principal component has been extracted, and the coolant pressure signal from which only the principal component has been extracted. Analyze the correlation between This analysis yields the graph illustrated in FIG. Further, the signal analysis unit 14 performs a correlation analysis on the reactivity signal from which only the main component is extracted and the coolant pressure signal from which only the main component is extracted, taking into account the phase shift (time delay). This analysis yields the graph illustrated in FIG. The output unit 18 outputs the analysis results (for example, the graphs in FIGS. 4 and 5) by the signal analysis unit 14 to a display device.

The analyst sets a function set by referring to the analysis results displayed on the display device. For example, the analyst may determine that the functions included in the function set are linear functions (e.g., f1(t)=a×t), quadratic functions (e.g., f2(t)=b×t ² ), multiple functions (e.g., several hundred) trigonometric functions (e.g., f3(t)=c×sin(ωn×t)), multiple linear functions x trigonometric functions (e.g., f4(t)=d×t+e×sin(ωn×t)) ). The analyst inputs the estimated function set into the measuring device 10. The input receiving unit 12 registers the input function set in the storage unit 17 (step S5).

When the function set is registered, or when it is determined in step S3 that the function set is not set, the signal reconstruction unit 15 then creates a function that reproduces the reactivity signal using the function set (step S6). . The signal reconstruction unit 15, for example, makes the waveform of the function F1(t), which is a linear sum of functions included in the function set, approximate the waveform of the reactivity signal, which is composed only of principal components after singular value decomposition. Then, each coefficient (for example, a to e) of the function F1(t) is calculated. For example, the signal reconstruction unit 15 performs fitting between the function F1(t) using the least squares method and the reactivity signal after singular value decomposition, and adjusts the values of the coefficients. The signal reconstruction unit 15 records the reactivity coefficients in the storage unit 17 after the adjustment is completed.

Next, the signal reconstruction unit 15 uses the function set to create a function that reproduces the coolant pressure signal (step S7). For example, the signal reconstruction unit 15 approximates the waveform of the function F2(t), which is a linear sum of functions included in the function set, to the waveform of the coolant pressure signal, which is composed only of principal components after singular value decomposition. Each coefficient (for example, a to e) of the function F2(t) is calculated as follows. For example, the signal reconstruction unit 15 performs fitting between the function F2(t) by the least squares method and the coolant pressure signal after singular value decomposition, and adjusts the value of the coefficient. The signal reconstruction unit 15 records the coefficient for the coolant pressure after the adjustment is completed in the storage unit 17.

When the fitting is completed, the signal reconstruction unit 15 reconstructs the reactivity signal after singular value decomposition and the coolant pressure signal after singular value decomposition using a set of functions (step S8). The signal reconstruction unit 15 applies the coefficients calculated in step S6 to the function F1(t), and reconstructs a signal that approximates the reactivity signal after singular value decomposition using the function F1(t). Create a degree signal (re). The signal reconstruction unit 15 applies the coefficients calculated in step S7 to the function F2(t), and reconstructs a signal that approximates the coolant pressure signal after singular value decomposition using the function F2(t). Create a coolant pressure signal (re) of the coolant pressure.

Next, the noise analysis method execution unit 16 calculates a coolant pressure coefficient using the reconstructed reactivity signal (re) and the reconstructed coolant pressure signal (re) (step S9). The noise analysis method execution unit 16 decomposes the reactivity signal (re) and the coolant pressure signal (re) into frequencies by fast Fourier transform. Next, the noise analysis method execution unit 16 uses the frequency-specific reactivity signal (re) and the frequency-specific coolant pressure signal (re) to calculate a correlation value between the frequency-specific coolant pressure coefficient and the frequency-specific signal strength. (coherence). Here, if the frequency is ω1, the reactivity signal (re) is ρ, and the coolant pressure signal (re) is p, then the coolant pressure coefficient (ω1)=ρ(ω1)÷p(ω1). As a result, graph 203 in FIG. 2 is obtained. Next, the noise analysis method execution unit 16 selects frequencies whose correlation values are equal to or greater than the threshold value. For example, the noise analysis method execution unit 16 selects a frequency with a correlation value of 0.4 or more. Next, the noise analysis method execution unit 16 calculates the average value of the coolant pressure coefficient (ω1) at the selected frequency. This average value is the final coolant pressure coefficient. Thereby, the coolant pressure coefficient can be calculated based on the coolant pressure signal and the neutron flux signal acquired from the nuclear power plant in operation.

Note that the processing in steps S1 to S8 corresponds to the first evaluation flow shown in FIG. 2, and the processing in step S9 corresponds to the second evaluation flow shown in FIG.

In general, in BWR nuclear power plants where only the coolant pressure signal and reactivity signal (neutron flux signal), which have large noise components, can be measured, it is difficult to find effective correlation components between the data, so general noise analysis methods are used. In measurements, it is difficult to determine a reliable coolant pressure coefficient. In contrast, in this embodiment, by combining function sets, a coolant pressure signal for evaluation and a reactivity signal for evaluation from which noise components have been removed are obtained. Thereby, the coolant pressure coefficient of a BWR type nuclear power plant can be measured using a general noise analysis method used in a PWR type nuclear power plant. According to this embodiment, the coolant pressure coefficient among the furnace physical parameters can be measured. Note that the method for measuring the coolant pressure coefficient of this embodiment may be executed for a PWR type nuclear power plant.

Further, as a modification of the coolant pressure coefficient measuring method in this embodiment, a moderator temperature coefficient measuring device for measuring the moderator temperature coefficient of a BWR type nuclear power plant can be realized. In this case, the signal acquisition unit 11 inputs a time-series signal of the moderator temperature instead of the coolant pressure signal. The subsequent processing is performed in the same manner as in this embodiment, with the coolant pressure signal replaced by the moderator temperature signal. As a result, it is possible to obtain measured values from an operating BWR type nuclear power plant and calculate the moderator temperature coefficient.

FIG. 9 is a diagram showing an example of the hardware configuration of the coolant pressure coefficient measurement system according to the embodiment.
The computer 900 includes a CPU 901, a main storage device 902, an auxiliary storage device 903, an input/output interface 904, and a communication interface 905.
The above-described reactivity measuring device 3 and measuring device 10 are installed in a computer 900. Each of the above-mentioned functions is stored in the auxiliary storage device 903 in the form of a program. The CPU 901 reads the program from the auxiliary storage device 903, expands it to the main storage device 902, and executes the above processing according to the program. Further, the CPU 901 reserves a storage area in the main storage device 902 according to the program. Further, the CPU 901 secures a storage area in the auxiliary storage device 903 to store the data being processed according to the program.

Note that a program for realizing all or part of the functions of the reactivity measuring device 3 and the measuring device 10 is recorded on a computer-readable recording medium, and the program recorded on this recording medium is read into a computer system. , the processing by each functional unit may be performed by executing . The "computer system" here includes hardware such as an OS and peripheral devices. Furthermore, the term "computer system" includes the homepage providing environment (or display environment) if a WWW system is used. Furthermore, the term "computer-readable recording medium" refers to portable media such as CDs, DVDs, and USBs, and storage devices such as hard disks built into computer systems. Further, when this program is distributed to the computer 900 via a communication line, the computer 900 that received the distribution may develop the program in the main storage device 902 and execute the above processing. Further, the above program may be one for realizing a part of the above-mentioned functions, and further may be one that can realize the above-mentioned functions in combination with a program already recorded in the computer system. .

As described above, several embodiments according to the present disclosure have been described, but all these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention as well as within the scope of the invention described in the claims and its equivalents.

<Additional notes>
The coolant pressure coefficient measuring method, coolant pressure coefficient measuring system, and program described in each embodiment can be understood, for example, as follows.

(1) The method for measuring the coolant pressure coefficient according to the first aspect includes time-series coolant pressure measurement data and reactivity measurement data (coolant pressure signal and reaction rate measurement data, respectively) measured during the operation of a nuclear power plant. (S1), and a step (S2) of executing processing (singular value decomposition) for extracting principal components from each of the measured data of the coolant pressure and the measured data of the reactivity. , creating the reactivity evaluation data (reactivity signal (re)) that approximates the main component of the reactivity measurement data by a combination of a plurality of functions (S6, S8); creating evaluation data of the coolant pressure (coolant pressure signal (re)) that approximates the main component of the measured data by combining the plurality of functions (S7, S8); and the measured data of the coolant pressure. a step (S8) of reconstructing each of the main components of the reactivity measurement data and the main components of the reactivity measurement data by a combination of a plurality of functions; and the coolant pressure evaluation data (coolant pressure signal (re)). and a step (S9) of executing a noise analysis method using the reactivity evaluation data (reactivity signal (re)).

By extracting the principal components from the measured data of coolant pressure and the measured data of reactivity, and reconstructing these principal components using a function set, noise components are removed from the measured data of coolant pressure and reactivity. Even if a large amount of Thereby, even if the coolant pressure measurement data and the reactivity measurement data contain many noise components, the coolant pressure coefficient can be measured.

(2) A method for measuring a coolant pressure coefficient according to a second aspect is the method for measuring a coolant pressure coefficient according to (1), in which the plurality of functions used for creating the evaluation data of the reactivity and the coolant The plurality of functions used to create the pressure evaluation data is one function group, and in the step of creating the reactivity evaluation data, the functions included in the function group are combined to measure the reactivity. In the step of creating a first function (F1(t)) that approximates the principal component of the data (S6) and creating evaluation data of the coolant pressure, the functions included in the function group are combined to A second function (F2(t)) that approximates the principal component of the pressure measurement data is created (S7).
Regarding coolant pressure and reactivity, which should originally have a correlation, the correlation cannot be confirmed due to large noise components, but the measured data of coolant pressure was combined with functions of the same type (functions with high correlation). By creating a function that approximates the measured data of reactivity and reactivity, it is possible to replace it with a correlated one. In addition, since the noise component is large when the original measurement data of the coolant pressure and the measurement data of the reactivity are used as targets, the main components of the measurement data of the reactivity and the main components of the measurement data of the coolant pressure are By making it a target, reconstruction processing is realized.

(3) The coolant pressure coefficient measuring method according to the third aspect is the coolant pressure coefficient measuring method of (1) to (2), in which the main component of the measurement data of the reactivity and the coolant pressure are The method further includes a step (S4) of analyzing correlations including phase shifts with respect to principal components of the measurement data.
By referring to the analysis results, it is possible to decide what kind of functions to select as a function set. In addition, since the noise component is large when the original measurement data of the coolant pressure and the measurement data of the reactivity are analyzed, the main component of the measurement data of reactivity and the main component of the measurement data of coolant pressure are This makes it easy to analyze correlations.

(4) A method for measuring a coolant pressure coefficient according to a fourth aspect is the method for measuring a coolant pressure coefficient according to (3), and includes setting of the plurality of functions selected based on the correlation analysis results. The method further includes a step of accepting.
Based on the correlation analysis results, the principal components of the time series data of coolant pressure and the principal components of the time series data of reactivity are common, and the principal components of the time series data of coolant pressure and the time series data of reactivity are common. Select a group of functions that can express each of the principal components. Then, a function group (function set) resulting from the selection can be set.

(5) The coolant pressure coefficient measuring method according to the fifth aspect is the coolant pressure coefficient measuring method according to (1) to (4), in which the plurality of functions include main components of the reactivity measurement data. A function (sin function) corresponding to a phase shift between the component and the main component of the measured data of the coolant pressure is included.
For example, if the phase shift is 90° and 270°, a sine function is included in the function set. By selecting a periodic function that corresponds to the phase shift, the accuracy when reconstructing the signal is improved.

(6) The coolant pressure coefficient measuring method according to the sixth aspect is the coolant pressure coefficient measuring method according to (1) to (5), wherein the plurality of functions include a linear function, a quadratic function, a triangular Contains functions, functions multiplied by linear functions and trigonometric functions.
By combining these functions, it is possible to precisely reproduce the measured data of the coolant pressure from which the main components were extracted and the measured data of the reactivity from which the main components were extracted.

(7) The coolant pressure coefficient measurement system 1 according to the seventh aspect includes an acquisition unit (signal acquisition part 11), a principal component extraction part (singular value decomposition execution part 13) that executes a process of extracting a principal component from each of the measured data of the coolant pressure and the measured data of the reactivity, and the reactivity The reactivity evaluation data that approximates the main component of the measured data of is created by a combination of a plurality of functions, and the coolant pressure evaluation data that approximates the main component of the coolant pressure measurement data of the plurality of a noise analysis method execution unit 16 that executes a noise analysis method using a reconstruction unit (signal reconstruction unit 15) created by a combination of functions, the coolant pressure evaluation data, and the reactivity evaluation data; and.

(8) The program according to the eighth aspect includes the steps of: acquiring time-series coolant pressure measurement data and reactivity measurement data measured during operation of a nuclear power plant; Executing a process of extracting a principal component from each of the measurement data and the reactivity measurement data, and extracting the reactivity evaluation data that approximates the principal component of the reactivity measurement data using a plurality of functions. creating the coolant pressure evaluation data that approximates the main component of the coolant pressure measurement data by combining the plurality of functions; and the coolant pressure evaluation data; and executing a noise analysis method using the reactivity evaluation data.

1... Coolant pressure coefficient measurement system 10... Measuring device 11... Signal acquisition section 12... Input reception section 13... Singular value decomposition execution section 14... Signal analysis section 15... Signal reconstruction unit 16...Noise analysis method execution unit 17...Storage unit 18...Output unit 2...Nuclear plant 3...Reactivity measuring device 900...Computer 901...CPU
902... Main storage device 903... Auxiliary storage device 904... Input/output interface 905... Communication interface

Claims (7)

obtaining time-series coolant pressure measurement data and reactivity measurement data measured during operation of the nuclear plant;
Executing a process of extracting a main component from each of the coolant pressure measurement data and the reactivity measurement data;
creating the reactivity evaluation data that approximates the main component of the reactivity measurement data by combining a plurality of functions;
creating evaluation data of the coolant pressure that approximates the main component of the measured data of the coolant pressure by a combination of the plurality of functions;
performing a noise analysis method using the coolant pressure evaluation data and the reactivity evaluation data;
has
The plurality of functions used to create the reactivity evaluation data and the plurality of functions used to create the coolant pressure evaluation data are one function group,
In the step of creating the reactivity evaluation data, a first function that approximates the main component of the reactivity measurement data is created by combining the functions included in the function group;
In the step of creating evaluation data of the coolant pressure, functions included in the function group are combined to create a second function that approximates the main component of the measured data of the coolant pressure.
Coolant pressure coefficient measurement method. analyzing a correlation including a phase shift between the main component of the reactivity measurement data and the main component of the coolant pressure measurement data;
The method for measuring a coolant pressure coefficient according to claim 1 , further comprising: The coolant pressure coefficient measuring method according to claim 2 , further comprising the step of accepting settings for the plurality of functions selected based on the correlation analysis results. The plurality of functions include a function corresponding to a phase shift between a main component of the reactivity measurement data and a main component of the coolant pressure measurement data,
The method for measuring a coolant pressure coefficient according to any one of claims 1 to 3 . The plurality of functions include a linear function, a quadratic function, a trigonometric function, and a function obtained by multiplying a linear function and a trigonometric function.
The method for measuring a coolant pressure coefficient according to any one of claims 1 to 4 . an acquisition unit that acquires time-series coolant pressure measurement data and reactivity measurement data measured during operation of the nuclear plant;
a principal component extraction unit that executes a process of extracting a principal component from each of the coolant pressure measurement data and the reactivity measurement data;
The reactivity evaluation data that approximates the main component of the reactivity measurement data is created by a combination of a plurality of functions, and the coolant pressure evaluation data that approximates the main component of the coolant pressure measurement data is created. a reconfiguration unit created by combining the plurality of functions;
a noise analysis method execution unit that executes a noise analysis method using the coolant pressure evaluation data and the reactivity evaluation data;
Equipped with
The plurality of functions used to create the reactivity evaluation data and the plurality of functions used to create the coolant pressure evaluation data are one function group,
The reconstruction unit combines the functions included in the function group to create a first function that approximates the main component of the reactivity measurement data,
combining the functions included in the function group to create a second function that approximates the main component of the coolant pressure measurement data;
Coolant pressure coefficient measurement system. to the computer,
obtaining time-series coolant pressure measurement data and reactivity measurement data measured during operation of the nuclear plant;
Executing a process of extracting a main component from each of the coolant pressure measurement data and the reactivity measurement data;
creating the reactivity evaluation data that approximates the main component of the reactivity measurement data by combining a plurality of functions;
creating evaluation data of the coolant pressure that approximates the main component of the measured data of the coolant pressure by a combination of the plurality of functions;
performing a noise analysis method using the coolant pressure evaluation data and the reactivity evaluation data;
has
The plurality of functions used to create the reactivity evaluation data and the plurality of functions used to create the coolant pressure evaluation data are one function group,
In the step of creating the reactivity evaluation data, a first function that approximates the main component of the reactivity measurement data is created by combining the functions included in the function group;
In the step of creating the coolant pressure evaluation data, the program executes a process of combining functions included in the function group to create a second function that approximates the main component of the coolant pressure measurement data. .

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