JP3376531B2 - Leak monitoring device and leak monitoring method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leakage monitoring apparatus and a leakage monitoring method for estimating the sound source intensity and position of a monitoring area by using outputs of a plurality of acoustic sensors installed around the monitoring area, and more particularly, to a leakage monitoring method. The present invention relates to a leak monitoring device and a leak monitoring method suitable for estimating the loudness and position of a sound that occurs with the noise.

[0002]

2. Description of the Related Art As a conventional leakage monitoring method, there is a method of monitoring the presence or absence of leakage and the position of leakage based on the presence or absence of the correlation of the output signals of a plurality of acoustic sensors installed around the monitoring area.
-200999, JP-A-62-255842, JP-A-2-38937 and the like.
In principle, all of these are accompanied by a delay according to the distance between the sensor and the leak point position when the leak sound generated at the leak point reaches multiple acoustic sensors, and the amplitude of the leak sound waveform is It is attenuated according to the above, but the shape of the waveform does not change, and the presence / absence of leakage and the position of leakage are obtained by arithmetic processing.

The system described in Japanese Patent Laid-Open No. 58-200999 uses coherence arithmetic processing as a main arithmetic processing.
Cross-correlation calculation is used as the main calculation processing. Both of the calculation processes are calculations for quantifying the similarity of detection signal waveforms between a plurality of acoustic sensors and the stability of the generation time difference.Normal noise is uncorrelated with each acoustic sensor, but leakage does not occur. When a leak occurs, the point at which the correlation between the outputs of the respective acoustic sensors becomes large is grasped so that the leak occurrence can be known. However, although the presence or absence of leakage and the leakage position can be known, the loudness of the leakage sound cannot be directly known. JP-A-62-255842
In the method described in the publication, the main calculation process is a phasing calculation process, but the obtained sound source intensity is a relative value of the monitoring area,
The absolute value of the sound source intensity was not calculated.

[0004]

Although the above-mentioned prior art can certainly monitor the presence or absence of leakage and the leakage position, since the absolute value of the leakage sound source intensity at the leakage position due to the leakage is not measured, the leakage after the occurrence of leakage is not measured. No sufficient consideration was given to the monitoring of the amount of leakage necessary in considering the response. In other words, if a leak occurs, it may be necessary to immediately stop the equipment if the amount is large, and if it is small, prepare a countermeasure for it and put it into a work-ready state, and then stop the equipment as much as possible. It is possible to consider saving time.

Therefore, an object of the present invention is to provide a function for estimating the sound source intensity at the leak point to obtain information on the magnitude of the leak amount, and a leak monitoring device which facilitates the countermeasure after the leak is detected by the operator. It is to provide a leakage monitoring method.

[0006]

The above-mentioned object is to perform a phasing operation for reducing the noise level on the output signals of a plurality of acoustic sensors arranged in the vicinity of the monitoring target area to perform the noise detection in the monitoring target area. A leakage monitoring apparatus comprising: a means for obtaining a sound source intensity distribution with reduced noise; and a means for determining a leakage position and the presence / absence of leakage from the sound source intensity distribution in the monitored area, wherein the leakage position and the presence / absence of leakage are determined. The determining means determines a sound source intensity peak position as a leakage position from the noise source reduced sound intensity distribution in the monitored region, and then multiplies the sound source intensity at the leakage position by a correction coefficient according to the leakage position. by, the absolute value of the sound source intensity after correction in the leakage position, the absolute of the sound source intensity of the corrected
This can be achieved by a leakage monitoring device characterized by being a means for determining the presence or absence of leakage from a value .

[0007]

The means for phasing output signals of a plurality of acoustic sensor signals arranged in the vicinity of the monitoring target area to obtain the sound source strength distribution of the monitoring target area is a function of obtaining the relative value of the sound source strength of each part of the monitoring target area. There is. The means for searching for a peak from the sound source intensity distribution of the monitored area has a function of determining the leak position by assuming that the point where the sound source intensity in the monitored area is the largest is the leak point. According to the conventional research and experience, there is only one leak point at the beginning of the leak, and there is almost no possibility that a plurality of leak points will occur at the same time. With the above configuration in which the means for multiplying the intensity at the peak position of the sound source intensity distribution by the correction coefficient according to the position is used, it is possible to obtain the absolute value of the sound source intensity at the leak point. By using the relationship between the leakage amount and the absolute value of the sound source intensity obtained experimentally in advance, it is possible to set the threshold value for determining the presence or absence of leakage.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an SG of a nuclear power plant according to the present invention.
It is an example applied to water leakage monitoring of (steam generator). SG
Sodium as a high temperature fluid and water as a low temperature fluid pass through the inside of the container body 705. Water passes through the water supply inlet pipe 703, the heat transfer pipe 707, and the steam outlet pipe 704 to SG.
It is guided to the outside of the container body 705. On the other hand, sodium enters the SG container barrel 705 through the sodium inlet pipe 701 and is guided to the outside of the SG through the sodium outlet pipe 702. The heat transfer tube 707 through which the water flows is spirally shaped into the SG container body 705.
It is installed inside and is supported by the heat transfer tube support structure 706. In other words, sodium and water are 70
5 inside is separated by a heat transfer tube 707 wall.

The sodium pressure during the operation of the nuclear reactor is almost atmospheric pressure, whereas the water inside the heat transfer tube 707 has a high pressure. Therefore, when a pinhole or the like is formed in the heat transfer tube 707, water leaks to the sodium side. At this time, a sound of water blowing and a sound due to a chemical reaction between sodium and water are generated. Further, hydrogen generated by the sodium-water reaction causes a pressure increase on the sodium side. When the pressure rises, a system is always provided to detect it and lower the pressure.However, the leak monitoring device of the present invention detects the leak before that, and thus the reactor output decreases or the leak occurs. It exists in order to facilitate the handling including the stop processing of the existing system.

In FIG. 1, acoustic sensors 101 to 109 are installed on the outer wall of the SG container body 705. This is installed to detect the sound of water blowing and the sound of sodium-water reaction. These plural acoustic sensors 101 to
The output signal of 109 is amplified by the amplification unit 20 to a level at which AD conversion can be performed accurately. In the AD conversion unit 30,
The acoustic signal that changes moment by moment is converted into a digital signal. The beamforming calculation unit 40 estimates the sound source intensity distribution inside the SG container body 705 using the association of a plurality of acoustic signals. The leakage determination processing unit 50 determines the leakage position based on the sound source intensity distribution estimated by the beamforming calculation processing unit 40, estimates the absolute value of the sound source intensity, and determines whether a problematic leak occurs from the absolute value of the sound source intensity. To judge.
The display / recording unit 60 performs display / recording processing including other process signals and measurement signals based on the leakage determination result.

Next, the functions and operations of the beamforming calculation unit 40 and the leakage determination processing unit, which are the main parts of the present invention, will be described in detail. 2 to 5 are views showing the concept of beamforming, and the principle of the sound source intensity estimation method by beamforming calculation will be described using this. Basically, it tries to estimate the acoustic signal of the sound source point by using the output signals of multiple acoustic sensors, and corrects the amplitude attenuation and time delay until the acoustic waveform reaches the acoustic sensor. Estimate the acoustic waveform of a point.

2 to 5, FIG. 2 shows the relationship between the sound generated at the leak point and the output of the surrounding acoustic sensor. The acoustic sensor output depends on the sound source intensity at the leak point and the distance between the leak point and the acoustic sensor. FIG. 3 shows the output waveform of each acoustic sensor when the leakage sound is a damped vibration waveform. As indicated by the formula shown in FIG. 2, the output of the acoustic sensor located farther from the leak point has a smaller amplitude and a longer time delay. Here, since the positional relationship between the leak position and the acoustic sensor is clear, attenuation and time delay due to the distance between the leak point and the acoustic sensor can be corrected for each output of each acoustic sensor. The result of this correction is shown in FIG. FIG. 4 is an acoustic waveform generated at a leak point, that is, a sound source point. A signal waveform obtained by normalizing the addition result of the corrected output signals of the four sensors by the number of sensors is shown in the bottom of FIG. The amplitude of the damped oscillatory wave generated by the leakage is the same as the output of each acoustic sensor,
It can be seen that the noise level peculiar to each acoustic sensor is reduced.

In the following, the signal shown in the bottom of FIG. 4 obtained as a result of adding the respective signals after correcting the time delay and the amplitude attenuation due to the distance of each acoustic sensor is called a beamforming signal. FIG. 5 shows a beamforming signal when a position slightly deviated from the leak point is considered as an actual sound source point. It can be seen that the damping oscillatory wave generated due to the leakage is small because the phases of the corrected acoustic sensor output signals are not aligned. When the beamforming signal is obtained by correcting the change in acoustic wave due to distance, if the distance information for correction is correct , that is, the virtual sound source position and leakage
If the leak position matches , a large amplitude is obtained as shown in FIG. 4 , and if it is not correct, the amplitude becomes small.

Here, the square of the effective value of the beamforming signal is the intensity of the sound source. According to this concept, if many virtual sound source points are assumed in the leakage monitoring target area, the sound source intensity of each virtual point is obtained, and the sound source intensity distribution is created, the sound source intensity becomes large at the actual leak point. It is possible to obtain a distribution in which the intensity of the other points is small. If the peak of this sound source intensity distribution can be found, the leakage position can be known. That is, the sound source intensity distribution inside the SG container can be estimated by using the output signals of the acoustic sensors 101 to 109 installed on the outer wall of the SG container body 705. However, since there is actually a problem as shown in FIG. 6, it is necessary to construct a leak monitoring system in consideration of this point.

The problem of the leak detection method for estimating the sound source intensity by the beam forming method and the solution to the problem in the present invention will be described with reference to FIG. For simplification of the explanation, two acoustic sensors are arranged on a straight line, and the sound source intensity on the straight line between the sensors is estimated. FIG. 6A shows the relationship between the acoustic sensor arrangement and the actual sound source points. FIG. 6B shows a case where both the time delay and the amplitude are corrected in the calculation of the beamforming signal, as described with reference to FIGS. 2 to 5. In FIG. 6C, only the time delay is corrected,
This is the case where amplitude correction is not performed.

As can be seen from FIG. 6B, the sound source intensity is 1 in this case, but it can be correctly estimated to be 1 at any actual sound source point. On the other hand, in most cases in FIG. 6C, the intensity of the actual sound source point is not 1. In FIG. 6B, there exists a sound source point having an intensity higher than that of the actual sound source point. In FIG. 6C, there is a peak at the actual sound source point, and the intensity at other points is flat. From the viewpoint of leakage monitoring, that is, it is desirable that a peak occurs at an actual sound source point and the intensity of other points is flat because of the ease of searching for leakage points.
Further, from the viewpoint of monitoring the leakage amount, the estimated intensity should be equal to the absolute intensity of the actual sound source point. Therefore, in the present invention, as will be described later in detail, the leak position is determined by the beam forming method without amplitude correction, and then the sound source intensity correction coefficient for each leak point is calculated in advance based on the presence or absence of amplitude correction. , The method of knowing the absolute value of the sound source intensity by correcting the sound source intensity at the actual leakage position. This allows
Time and as compared with the case of simultaneously correcting processing amplitude of both the amplitude correction is applied only to the intensity of the leakage position
Because, the arithmetic processing amount Fewer, apparatus size also need not be large.

FIG. 6B shows that the estimated sound source intensity varies depending on whether the sound source is close to the sensor. In order to show this difference, the sound source intensity estimation results for both the case where the sound source is close to the sensor and the case where the sound source is farther than the sensor are shown in the following description. The former is referred to as a dense arrangement of sensors, and the latter is referred to as a sparse arrangement of sensors.

FIGS. 7-10 are in line with FIG.
The problem of amplitude correction, which was described for the point source ,
It is a figure for explaining that it is the same also about an existing point sound source . The sound source intensity distribution on the cross section of the SG container body 705 is obtained. FIG. 7 shows the case where the actual leak point is at the end and the sensors are densely arranged, and FIG. 8 shows the case where the actual leak point is at the end and the sensor is sparsely arranged. 9 shows that the actual leak point is in the center and the sensors are densely arranged.
Shows the case where the actual leak point is in the center and the sensors are sparsely arranged. still,
Amplitude correction is performed in each of FIGS. 7 to 10. In each drawing, (a) is a bird's-eye view and (b) is a plan view.
For estimating the sound source intensity of a point sound source existing in a three-dimensional monitoring area
In this case, the attenuation due to the distance between the sensor and the virtual sound source position is compensated.
The same problem arises because you will be doing positive.

As shown in FIGS. 7 to 10, the obtained sound source intensity distribution shows the same tendency as in the case where the acoustic sensors are arranged one-dimensionally. That is, when the actual leak point is at the end, the sound source intensity on the opposite side may be larger than the actual sound source point in some cases, and when the actual sound source point is in the center, the sound source intensity at the end is large, but the actual sound source point Less than the strength of. This is the result of calculation assuming that the frequency band of the leakage sound is sufficiently wide.

Next, another problem when the beam forming method is applied to the leakage monitoring and the corresponding method in the present invention will be described. This problem is a so-called aliasing phenomenon. Aliasing results in false intensity peaks in the sound source intensity distribution. This is a problem related to the arrangement density of acoustic sensors used for monitoring. In other words, 1/2 the wavelength of the monitored frequency of the acoustic signal
There is no problem if the acoustic sensors are arranged at shorter intervals, but in order to reduce the cost of the entire monitoring device, it may be necessary to reduce the acoustic sensor arrangement density even if the occurrence of aliasing is allowed. is there. In this embodiment,
In terms of cost, we have reduced the placement density to reduce the effects of aliasing by other means.

11 to 14 show examples of sound source intensity distributions obtained by simulation when leaked sound is white. 11 and 12 show a case with amplitude correction, and FIGS. 13 and 14 show a case without amplitude correction.
Note that FIGS. 11 and 13 show densely arranged sensors, and FIGS. 12 and 14 show sparsely arranged sensors. (A) is a bird's-eye view and (b) is a plan view.

In particular, as can be seen from the comparison with FIGS. 11 to 13 , the estimated sound source intensity distributions other than the actual sound source points should change smoothly or be flat. However, the figure
12 to 14, small peaks due to aliasing occur in places. In the case of peak search, the greater the difference in intensity or the difference in intensity ratio between the actual sound source point intensity and the other points, the higher the reliability of the peak search and the easier the search. From this point of view, such a small peak in some places becomes noise in the peak search. The peaks at these places are phenomena caused by aliasing, and are components that do not occur if the arrangement interval of the acoustic sensors is narrowed. However, increasing the density of the acoustic sensor arrangement so that aliasing does not occur causes an increase in the size of the leakage monitoring device. The generation pattern of false peaks due to aliasing is determined by the placement of the acoustic sensor, the frequency component of the leak sound, and the leak point position. Therefore, in the present invention, as described in detail below, in peak search, pattern matching is performed in consideration of aliasing to reduce the effect.

FIG. 15 shows the operation of the leakage monitoring apparatus shown in FIG. 1, and the operation of the entire monitoring apparatus will be described with reference to this figure. This monitoring procedure covers the solution for application of the above-mentioned beamforming method to leakage monitoring. When the monitoring process starts, the leak monitoring area is first set. In the present embodiment, the SG container body 705 is sliced to calculate a sound source intensity distribution in a circular cross section, and leakage is monitored from the sound source intensity distribution. Further, the scanning direction of the cross section is from bottom to top, but there is no particular problem in top to bottom or other scanning. Next, with respect to the output signal of the acoustic sensor corresponding to the monitoring area, the magnitude of the time delay correction is changed and the sound source intensity distribution of the monitoring area is calculated by the beamforming method. Since the calculation result of the sound source intensity distribution only once has a large variation due to the time variation of the signal and noise, the sound source intensity distribution obtained in the previous scan is averaged to reduce the variation.

Next, a leak point search process is performed. In the leak point search process, a simple peak search can be performed, but a peak search is performed here by pattern matching. That is, the sound source intensity distribution pattern for each leak point calculated in advance is compared with the estimated sound source intensity distribution pattern obtained at the time of monitoring to determine the leak point position of the sound source intensity distribution pattern of the closest pattern. In this case, the frequency distribution of the leak sound or noise is estimated by using the one obtained experimentally in advance. Specifically, a virtual leak point is determined, the sound source intensity is adjusted to obtain the minimum value of the inter-pattern distance, and this scanning is performed on the entire monitoring area. Then, by further calculating the minimum value in the minimum distance difference obtained for each virtual leak point,
Let the leaking virtual point corresponding to it be a leaking point. Further, the absolute value of the leakage sound intensity is obtained by the correction coefficient obtained in advance. Next, the sound source intensity is converted into the leak amount based on the relationship between the sound source intensity and the leak amount that has been experimentally obtained. Depending on the magnitude of this leakage amount, the warning method and the display method are carried out according to a predetermined method. After the end, the next monitoring area is set and the same processing is repeated.

Next, the operation of the alarm processing unit in this embodiment will be described. This leak detector displays the correlation between the trend of the sodium hydrogen meter output that is usually used in a nuclear power plant for detecting the maximum leak amount and the small leak and its time variation. As a result, the operator can know the relationship between the hydrogen meter and the leakage amount (sound source intensity) in the normal state, and therefore, it becomes possible to have higher reliability for the alarm due to the change when the alarm is issued. In addition, by displaying the distribution of the leakage amount (sound source intensity) inside the SG container, the situation inside the SG container under normal conditions can be known to some extent, and the difference can be grasped when an alarm is issued. I can play. When a leak alarm is issued, the wastage rate (corresponding to the fragility of the pipe near the leak point) is calculated and displayed from the relationship between the sodium temperature and the leak amount, the guidance of the necessity of response is displayed, and the self-plug (pin once opened) is displayed. Guidance is displayed to indicate whether there is a possibility that the hole will be closed again due to heat from sodium-water reaction and the leakage will spontaneously stop).

In the present embodiment, with the configuration and functions described above, leakage monitoring inside the SG is realized so that the operator can more easily deal with abnormal situations. In the present embodiment described above, the peak search can be simply a maximum value search. If the acoustic sensor arrangement density is realized to some extent, the size of the false peak due to aliasing does not become larger than the actual sound source intensity. Further, in the case of pattern matching, if compared with the sound source intensity distribution by amplitude correction (sound source intensity distribution of absolute value), the subsequent absolute value correction processing becomes unnecessary.
If a mechanism for monitoring the rate of change of the leak amount over time is added to the leak determination condition, it is possible to monitor the leak amount even more minutely. As described in the above embodiments, by configuring the leakage monitoring device as described above, it is possible to monitor the absolute value of the sound source intensity.

The following are specific effects of the present embodiment described above.

(1) Since the influence of aliasing is reduced by the signal processing, it is not necessary to increase the size of the device, which has the effect of improving the economical efficiency for realizing the leakage monitoring device.

(2) An absolute value monitoring function can be added by simply multiplying the correction coefficient by the intensity of the leak point.
There is no need to increase the burden on the arithmetic processing unit or the size of the device, and there is an effect of improving the economical efficiency for realizing the leakage monitoring device.

(3) Since the presence or absence of leakage can be confirmed by the two detection systems by the correlation display between the hydrogen meter and the sound source intensity, there is an effect of improving the reliability of leakage monitoring.

(4) The addition of guidance display functions such as a wastage rate calculation and a display function makes it possible to further facilitate the operator's decision on the appropriate treatment, thus improving the operation efficiency of the nuclear power plant.

(5) It is possible to monitor the time variation of the absolute value of the sound source intensity, which has the effect of improving the performance of the leakage monitoring device.

(6) Since the amount of leakage can be known, the large leak detection system of the pressure detection system used in the conventional plant can be eliminated, the manufacturing cost of the plant can be reduced, and the economical efficiency is improved. Has the effect of.

[0034]

As described above, according to the present invention, it is possible to estimate the sound source intensity at the leak point, and as a result, the magnitude of the leak amount can be known. As a result, it is possible to speed up the recovery work after unnecessary stoppages and leaks, which has the effect of improving the operation efficiency of the nuclear power plant.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of application of a leak monitoring device according to an embodiment of the present invention to SG leak monitoring.

FIG. 2 is a diagram showing a relationship between a sound generated at a leak point and an output of a surrounding acoustic sensor.

FIG. 3 is a diagram showing an output waveform of each acoustic sensor when the leakage sound is a damped vibration waveform in the positional relationship shown in FIG.

4 is a diagram showing an acoustic waveform generated at a leak point, that is, a sound source point in the positional relationship shown in FIG.

5 is a diagram showing a beamforming signal when a position slightly deviated from a leak point in the positional relationship shown in FIG. 2 is considered as an actual sound source point.

FIG. 6 is an explanatory diagram showing a difference in a sound source intensity estimation result due to a difference in a beamforming method correction method, and FIG.
FIG. 4A is a diagram showing a beamforming sensor arrangement in a one-dimensional system, FIG. 7B is a diagram showing a sound source intensity when amplitude is corrected, and FIG. 8C is a diagram showing a sound source intensity when a conventional amplitude is corrected.

7 is a diagram showing a sound source intensity distribution in the three-dimensional system of the present embodiment shown in FIG. 1, in the case where the actual leak point is at the end and the sensors are densely arranged, (a) is a bird's-eye view, FIG. (B) is a plan view.

FIG. 8 is a diagram similar to FIG. 7 in the case where the sensors are sparsely arranged, in which (a) is a bird's-eye view and (b) is a plan view.

9 is a diagram similar to FIG. 7 in the case where the actual leak point is in the center and the sensors are densely arranged, (a) is a bird's-eye view, and (b) is a plan view.

FIG. 10 is similar to FIG. 7, in the case where the actual leak point is in the center and the sensors are densely arranged, (a) is a bird's-eye view, and (b) is a plan view.

FIG. 11 is an example in which a sound source intensity distribution in the case where the leaked sound is white is obtained by simulation, and shows a sound source intensity estimation result when the sensors are densely arranged and amplitude correction is performed. Bird's-eye view, (b) is a plan view.

12 shows a sound source intensity estimation result when the sensors are sparsely arranged in the example of FIG. 11, (a) is a bird's-eye view, and (b) is a diagram.
Is a plan view.

13A and 13B show a sound source intensity estimation result when the sensors are densely arranged and amplitude correction is not performed in the example of FIG. 11, FIG. 13A is a bird's-eye view, and FIG. 13B is a plan view.

14A and 14B show a sound source intensity estimation result when the sensors are sparsely arranged and amplitude correction is not performed in the example of FIG. 11, where FIG. 14A is a bird's-eye view and FIG. 14B is a plan view.

FIG. 15 is an explanatory diagram of a leakage monitoring procedure.

[Explanation of symbols]

101-109 acoustic sensor 20 Amplifier 30 AD converter 40 Beamforming calculation unit 50 Leakage determination processing unit 60 Display / recording section 701 Sodium inlet piping 702 Sodium outlet piping 703 Water supply inlet piping 704 Steam outlet piping 705 SG (steam generator) container barrel 706 Heat transfer tube support structure 707 heat transfer tube

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Haruo Fujimori 7-2-1 Omika-cho, Hitachi-shi, Ibaraki Energy Research Laboratory, Hitachi, Ltd. (56) Reference JP-A-58-200999 (JP, A) SHO 62-255842 (JP, A) JP 58-168934 (JP, A) GAUBATZ DC, GREEND A, "Acoustic leak-detection / l (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) G21C 17/025 GDF G21C 17/00

Claims (7)

(57) [Claims] 1. A sound source intensity distribution in which noise in a monitored area is reduced by performing a phasing operation for reducing a noise level on output signals of a plurality of acoustic sensors arranged in the vicinity of the monitored area. A leak monitoring device comprising: a means for obtaining the leak position and a means for determining the presence / absence of a leak from the sound source intensity distribution of the monitored area, wherein the means for determining the leak position and the presence / absence of the leak is the monitored object. After the sound source intensity peak position is determined as the leak position from the sound source intensity distribution in which the noise in the region is reduced, and then the sound source intensity at the leak position is multiplied by a correction coefficient according to the leak position to correct the leak position. of the absolute value of the sound source intensity, leakage monitoring device, characterized in that the means for determining the presence or absence of leakage from the absolute value of the sound source intensity of the corrected. 2. The leak monitoring apparatus according to claim 1, further comprising means for estimating a leak amount from an absolute value of a sound source intensity multiplied by the correction coefficient and performing display processing. 3. The leakage monitoring apparatus according to claim 2, further comprising a unit for displaying a guidance for countermeasures of a plant operator according to the estimated leakage amount. 4. The leak monitoring device according to claim 1, 2, or 3, wherein the means for searching the sound source intensity peak for determining the leak position is an aliasing standard according to the position of the sound source intensity peak and its intensity. A leak monitoring device comprising a pattern matching means. 5. A means for obtaining a sound source intensity distribution of a monitoring target area by performing a phasing operation and amplitude correction on output signals of a plurality of acoustic sensors arranged in the vicinity of the monitoring target area, and leakage of the monitoring target area calculated in advance. Means for obtaining the peak position and its sound source absolute value by pattern matching with the absolute value intensity distribution for each position and the sound source intensity distribution obtained by phasing calculation and amplitude correction, and estimating the leakage amount from the sound source absolute value. And a display processing means. 6. A sound source intensity distribution in which noise in a monitored area is reduced by performing a phasing operation for reducing a noise level on output signals of a plurality of acoustic sensors arranged in the vicinity of the monitored area. A step of obtaining, a step of searching a sound source intensity peak from a sound source intensity distribution in which noise in the monitored region is reduced, and determining the sound source intensity peak position as a leakage position; and a correction coefficient according to the sound source intensity peak position. The step of obtaining the absolute value of the corrected sound source intensity at the leak position by multiplying the sound source intensity at the peak position of the sound source intensity, and the presence / absence of leakage is determined from the absolute value of the corrected sound source intensity to estimate the leak amount. And a step of displaying the countermeasure guidance of the plant operator according to the leakage amount, and the leakage position is determined by searching the sound source intensity peak. The leakage monitoring method, wherein a step of matching the position of the sound source intensity peak with an aliasing standard pattern according to the intensity is added to the determining step. 7. A step of obtaining a sound source intensity distribution of a monitoring target area by performing a phasing operation and amplitude correction on output signals of a plurality of acoustic sensors arranged near the monitoring target area, and leakage of the monitoring target area calculated in advance. A step of obtaining the peak position and its sound source intensity absolute value by pattern matching between the intensity distribution of the absolute value for each position and the sound source intensity distribution obtained by phasing calculation and amplitude correction, and estimating the leakage amount from the sound source intensity absolute value. And a display processing step.