JPH0464437B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an apparatus for evaluating transient signals generated when loose parts or the like mixed into plant equipment or piping constituting a plant system collide with the plant equipment or piping.

[Technical background of the invention and its problems]

For example, foreign objects such as objects left behind in the reactor during reactor construction or nuclear fuel exchange, or damaged objects due to falling or deteriorating parts of plant equipment may float in the primary reactor system as loose parts. Such loose parts tend to accumulate particularly at the bottom of the reactor pressure vessel and the steam generation section, and have an adverse effect on plant equipment or piping.

Therefore, in order to remove the loose parts from inside the plant equipment or piping, it is necessary to correctly evaluate the transient signal generated when the loose parts collide with the inner wall of the plant equipment or piping. by the way,
As a means of monitoring loose parts, a transient signal (analog signal) generated when a loose part collides with plant equipment or the inner wall of piping is converted into a digital signal, and this digital signal is subjected to fast Fourier transform (FET). Generally, a method is adopted in which frequency component data obtained by converting time domain data into frequency domain data is evaluated.

However, with the conventional transient signal evaluation device as described above, it is necessary to operate the device continuously at all times in order to capture transient signals that may occur at any time, and as a result, a huge amount of records may be kept. There was a problem that unnecessary expenses were incurred.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to operate the device only when a transient signal occurs in plant equipment or piping to accurately evaluate a transient signal. is to provide.

[Summary of the invention]

In order to achieve the above object, the present invention provides a detector installed in plant equipment or piping, and a negative delay device that is activated on the condition that the detection signal obtained from the detector exceeds the disk level. An A/D converter, a data partitioning device that separates the digital signal output from the A/D converter into at least noise signals and transient signals, and a spectrum analysis of each signal separated by the data partitioning device. and an arithmetic device that calculates a positive transient signal by subtracting the spectral component of a noise signal from the spectral component of the transient signal obtained by the spectral analysis device. It is.

First, the basic concept of the transient signal evaluation device according to the present invention will be explained.

7a to 7d show a method for determining a transient signal according to the present invention. In other words, Fig. 7a is a diagram showing the raw waveform α of the transient signal 1 in a noise-free situation, and when this raw waveform α is subjected to spectrum analysis in the time domain including the transient signal 1, it becomes 2 in Fig. 7b. It is expressed by spectral components as shown. On the other hand, FIG. 7c is a diagram showing the raw waveform β of the transient signal 3 when there is noise, and this raw waveform β
When spectral analysis is performed on the time domain including the transient signal 3, it is expressed by spectral components as shown in 5 in FIG. 7d. The spectral component 5 includes the spectral component 6 of the noise 4.

Therefore, in order to remove the spectral component 6 of the noise 4, a spectral analysis of the noise signal γ immediately before the transient signal 3 shown in FIG. subtract from the spectral components of That is, in FIG. 7d, if we subtract the spectral component 6 of the noise signal γ immediately before the transient signal 3 from the spectral component 5 of the raw waveform β, we get FIG. 7d.
A spectral component 7 is obtained as represented by the dotted line, and this spectral component 7 is the net transient signal 3
This means that the signal components of are evaluated.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block configuration diagram of an embodiment of the present invention, in which a detector 10 is installed in plant equipment and piping, and an analog signal obtained from this detector 10 is amplified by an amplifier 11. The signal is input to an A/D converter 12 with a minus delay. When this input analog signal exceeds the disc level, the trigger circuit is activated and
The D converter 12 receives a signal α for one data shown in FIG.
That is, a signal α consisting of a signal γ containing only background noise and an impact signal β containing background noise related to this signal γ is input to the next data partitioning device 13. The data partitioning device 13 separates the shock signal β including background noise and the signal containing only background noise (corresponding to the minus delay), and the respective signals β and γ are subjected to spectrum analysis in the spectrum analysis device 14. After performing this, it is input to the arithmetic unit 15,
In this arithmetic unit 15, the difference between the spectral components of both signals β and γ is calculated, and the spectral component of the net impact signal is determined. This result is displayed on the display 16 if necessary.

The present embodiment is configured as described above, and in particular, by using an A/D converter with a minus delay, the shock signal β including background noise and the signal immediately before the shock signal β appears. γ is collected as a 1-data signal α, and for this 1-data signal α, the impact signal β including noise and the noise-only signal are subjected to spectrum analysis, and the difference between the spectral components is taken as the spectral component of the positive impact signal. configured to evaluate.
Therefore, the A/D converter with a negative delay to which the detection signal is input is always on standby so that it can record the detection signal, and when the detection signal exceeds the disk level, the trigger circuit is activated to record one data. This is a very useful transient signal evaluation device because it records only the signal portion of the division and analyzes and calculates it, so there is no needless recording, and it can evaluate transient signals with a minimum of analysis calculations. can be provided.

FIG. 3 is a block diagram of another embodiment, and the same parts as in FIG. 1 are given the same reference numerals and will be explained.

Detector 1 installed in plant equipment and piping
The analog signal obtained from 0 is amplified by an amplifier 11 and input to an A/D converter 12 with a minus delay. When this input analog signal exceeds the disk level, the trigger circuit is activated and the A/D converter 12 with negative delay is activated as shown in FIG.
A signal α consisting of a signal α for data, that is, a signal γ containing only background noise, and a transient signal β containing background noise related to this signal γ
is input into the next data partitioning device 17. As shown in FIG. 5, the data sorting device 17 uses signals β ₁ , β ₂ , and β that classify the background noise signal γ (corresponding to the minus delay portion) and the transient signal β including the background noise over time. After the signals γ, β ₁ , β 2 and β ₃ are divided into ₃ and 3, the spectra of the signals γ, β ₁ , β 2 and β 3 are analyzed in the next spectrum analyzer 18, and the signals γ, β ₁ , β ₂ and β ₃ are shown in FIG. It is represented by spectral components as shown in a to d. Then, in the arithmetic unit 19, the signals β ₁ ,
When the difference between the spectral components of β ₂ , β ₃ and the signal γ is calculated, the difference becomes the shaded portions A, B, and C, respectively, as shown in FIG. 6b to d. Next, by calculating the average value of the shaded portions A, B, and C indicating this difference, the spectral component consisting of this average value is taken as the spectral component of the net transient signal. Then, this result is displayed on the display 20 if necessary.

FIG. 4 shows a flowchart of the transient signal evaluation device according to another embodiment of the present invention shown in FIG. 3, and its operation will be explained using this flowchart. That is, a detection signal obtained from a detector is amplified by an amplifier in a first step 101, and then in a second step 102 it is determined whether it is a transient signal or not. If the signal is not a transient signal, the process returns to the first step 101. If it is determined that the signal is a transient signal, in a third step 103, analog/digital conversion is performed on the signal α for one data consisting of the signal γ for the minus delay and the transient signal β. In the fourth step 104, data division is performed to further divide the signal γ and the transient signal β into signals β ₁ , β ₂ , β ₂ , and in the next fifth step 105 , each of the divided signals γ, β ₁ , β ₂ , and β ₃ respectively. Sixth step 106
Now, find the difference between the signals β ₁ , β ₂ β ₃ and the signal γ. In the next seventh step 107, the average of the differences is calculated, and in an eighth step 108, this average value is displayed as the spectral component of the net transient signal.

In the above embodiment, the data division between the minus delay signal γ and the transient signal β is 1.
Although the cases of 1:1 and 1:3 are explained, the ratio is not limited to this, and it goes without saying that any ratio can be selected.

〔Effect of the invention〕

As explained above, according to the present invention, when a signal is input, the A/D converter with minus delay is on standby so that the signal can be recorded at any time, and is triggered when the signal exceeds the disk level. It is possible to record the generated transient signal including the minus delay component, and to display the net spectral component of the transient signal by subtracting the noise spectral component from the spectral component of the transient signal.

Therefore, the device of the present invention does not need to be operated continuously like conventional devices, but only needs to be activated when a transient signal occurs, and has the advantage of being able to accurately evaluate transient signals. play.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.
2 shows a signal for one data input to the A/D converter with minus delay shown in FIG. 1, FIG. 3 shows a block diagram of another embodiment of the present invention, and FIG. Flowchart for explaining the operation of the embodiment, FIG. 5 is a flowchart for explaining the operation of the embodiment of
6a to 6d are diagrams representing the respective spectral components of the segmented signals γ, β ₁ , β ₂ , β ₃ in FIG. 5; FIG. 7a ~
d is a diagram for explaining the transient signal evaluation method according to the present invention. 10...Detector, 11...Amplifier, 12...A/D converter with minus delay, 13, 17...Data division device, 14, 18...Spectrum analysis device, 1
5, 19... Arithmetic device, 16, 20... Display device.

Claims (1)

[Claims] 1. A detector installed in plant equipment or piping, and an A/D converter with a negative delay that operates on the condition that the detection signal obtained from the detector exceeds the disk level. a data partitioning device that partitions the digital signal output from the A/D converter into at least a noise signal and a transient signal; and a spectrum analysis device that spectrally analyzes each signal partitioned by the data partitioning device. , and an arithmetic device that calculates a net transient signal by subtracting a spectral component of a noise signal from a spectral component of a transient signal obtained by the spectral analysis device. 2. The transient signal evaluation device according to claim 1, further comprising a data division device that classifies the digital signal output from the A/D converter with a minus delay into a noise signal and a plurality of transient signals.