JPH07104200B2 - Loose part position estimating device in flow path - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for monitoring parts (loose parts) dropped from equipment in a fluid channel of a nuclear reactor or the like, and in particular, the loose parts are channel walls. The present invention relates to a device for estimating the position of loose parts by detecting and processing a vibration sound generated by colliding with an object in a flow path.

(Prior Art) When a device part is dropped out in various circulation systems including flow passages of steam and liquid in a reactor device such as a reactor and a steam generator connected to the reactor, the dropout part (loose parts) ) Causes problems such as damage to various devices and obstruction of internal fluid flow. Nuclear technology requires greater safety than other technical fields, and it is necessary to reduce the occurrence of loose parts as much as possible.
In addition, if loose parts occur, it is necessary to detect the fact as soon as possible, and to accurately detect the occurrence site and the movement state of the loose parts. Therefore, various countermeasures have been conventionally considered, and applications such as Japanese Patent Application No. 56-120029 and Japanese Patent Application No. 61-233443 relating to the invention of the present inventor have been made. Of these, Japanese Patent Application No. 61-233443 describes a method for estimating the position of loose parts based on a detection signal from a sound wave detection accelerometer (sensor) closely arranged at three different positions of a measured object. ing.

The outline of the method will be described. As shown in FIG. 4, the coordinates of the sensor A are (x ₁ , y ₁ ) and the coordinates of the sensor B are (x ₂ ,
y ₂ ), sensor C coordinates (x ₃ , y ₃ ), loose part impact position P coordinates (x, y), sensor A to P distance d ₁ , sensor B to P distance Where d ₂ and the distance from sensor C to P are d ₃ , the following equation holds.

Further, as shown in FIG. 5, if the time differences t ₁ and t ₂ of the signal waveform rise of each sensor that receives the impact signal due to the collision of loose parts are obtained, the difference in the arrival time of the impact signal wave becomes the difference in the distance from the impact point. Since it corresponds, the following equation holds when the sound velocity is v.

(D ₁ −d ₂ ) = v × t ₁ (4) (d ₁ −d ₃ ) = v × t ₂ (5) where x ₁ , x ₂ , x ₃ , y ₁ , y ₂ , y ₃ Since the position of is known, the coordinates x and y of the impact position P can be obtained from the above equations (1) to (5), and the distances d ₁ and d ₂ from each sensor to the loose part generation position can be obtained. d ₃ can be calculated.

(Problems to be Solved by the Invention) In the method described in Japanese Patent Application No. 61-233443 (unknown), impact signals from sensors attached to at least three different positions are required. It was not possible to determine the exact impact position of loose parts from the impact signal of less than the number. In a reactor having a complicated conduit consisting of many devices such as a reactor device, it is necessary to install sensors for detecting loose parts in many places, and as the number of sensors increases, The device for recording and processing the signal from the sensor also becomes complicated. Therefore, it has been desired to develop a loose part position estimating method which is inexpensive and has few failures, by reducing the number of sensors as much as possible and simplifying the device as much as possible.

(Means for Solving Problems) The present invention has been made to solve the above problems, and in a loose parts position estimating device in a flow channel, at least two different devices constituting the flow channel are different. By mounting the sensor device at each position and performing a simulated impact test that is performed in advance, find the correlation between the distance from the impact point to each sensor device and the time required from the rising point to the peak point of the impact signal emitted from each sensor device. Based on the impact of the loose parts when the loose parts are generated, the required time from the rising point to the peak point of the impact signal emitted from each of the sensor devices is calculated.
It is characterized in that the position of the loose part is estimated with reference to the correlation.

(Example) An example of the present invention will be described with reference to Figs.
In FIG. 1, reference numerals 1 to 10 are acoustic wave detecting accelerometers (sensors) arranged in close contact with an object to be measured 100 such as a primary system pipe of a nuclear power plant. 11 to 20 are loose part detectors connected to the respective sensors. The signal from the loose parts detector is transmitted to the first event recorder 21, and the first event recorder 21 processes the signal from the detector and transmits it as a digital signal to the data recording device 22 as necessary. Based on the data from the data recording device, the loose parts digital analysis device 23 analyzes the data. In the loose parts detectors 11 to 20 shown in Fig. 1, the vibration noise detected by the accelerometers (sensors) 1 to 10 installed in the primary system piping or auxiliary equipment of the nuclear power plant is the background noise Compared to the above, an alarm signal is issued when there is a sudden impact sound, but the normal background noise and impact sound are compared, and an alarm is issued when the impact sound has a certain ratio or more. . In addition, after receiving the warning, the first event recorder 21 judges whether the warning is correct or not. If it is judged as an error, the warning is reset (reset). Data recording device 2
Record in 2. The data of this data recording device is analyzed by the loose part digital analysis device 23 to estimate the position of the loose part. The method will be described in detail below.

According to the experiments by the inventors, when an impact is given to an arbitrary position such as a piping system of a nuclear power plant, which is a measured object, the time of the impact signal wave detected by each sensor attached to the measured object When the waveform with respect to the axis is examined, it is found that there is a correlation between the time t from the rising start point of the impact signal waveform to the peak point of the waveform (maximum point of vibration width) and the distance from the impact point to each sensor mounting position. I have found

Therefore, by performing a simulated impact test in advance, each sensor mounted on the measured object is given an impact by changing the distance from the sensor, and the waveform of the impact signal transmitted from the sensor is recorded. From the rising point of the impact signal waveform, The relationship between the time to the peak point of the waveform and the distance from the impact point will be obtained. That is, the distance from the impact point to the sensor is d _{1 as} shown in FIG.
An impact instead of to d ₅ and 5 kinds, obtains a correlation diagram seek time t ₁ ~t ₅ from rising point a of the impact signal emanating from the sensor to the peak point b. A summary of this is shown in FIG. In the loose part detection system that has been subjected to such a simulation test, when a loose part occurs, an impact is given, and an impact signal from a sensor near the impact point is emitted from the loose part detector. This signal is an event recorder
21, the data recording device 22 is analyzed by the loose parts digital analysis device 23, the time from the rising point of the signal to the peak point is obtained, and the impact point or sensor The distance is calculated. Therefore, after performing the above operation on the impact signals from the two sensors with different mounting positions, two arcs are drawn with the distance from each of the two sensors to the impact point as a radius, and the intersection of these parts causes loose parts. It is an impact point.

Although the case where the present invention is applied to the nuclear power plant has been described above, the present invention is not limited to this and can be similarly applied to a thermal power plant such as a boiler. Further, in the embodiment, the method of estimating the impact point from the sensor signals attached to two different positions has been described, but the essence of the present invention is not limited to this, and the impact point is attached to three or more different positions. It can be easily understood from the content of the above-described embodiment that the method can be applied to the case of estimating the impact point from the obtained sensor signal.

(Effect of the Invention) According to the present invention, it is possible to estimate the position of a loose part by a signal from a sensor attached at least at two or more different places. It is possible to reduce the number of the loose parts, simplify the loose part detecting system, and provide a cheap loose part detecting method with less failure.

[Brief description of drawings]

FIG. 1 is a system diagram of a loose part position estimating device for explaining an embodiment of the present invention, FIG. 2 is an explanatory diagram of a simulated impact test performed prior to carrying out the present invention, and FIG. , FIG. 2 is a schematic diagram of the contents, and FIGS. 4 and 5 are explanatory views of the prior art. 1 to 10 …… Sensor, 11 to 20 …… Loose parts detector, 21 …… First event recorder, 22 …… Data recording device, 23 …… Loose parts digital analyzer.

Claims (1)

[Claims] 1. A loose parts position estimating device in a flow path, wherein a sensor device is attached to at least two different positions of a device forming the flow path, and each sensor device is measured from an impact point by a simulated impact test performed in advance. To the peak time and the required time from the rising point to the peak point of the impact signal emitted from each sensor device, and the impact signal emitted from each sensor device based on the impact of the loose part when the loose part occurs. A device for estimating the position of a loose part in a flow path, wherein a position required for the loose part is estimated with reference to the correlation, the required time from the rising point to the peak point of the above.