JP2600171Y2 - Leak detection device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak detecting device for detecting a leak of water from a pressure-resistant portion such as a vessel or a pipe constituting a plant.

[0002]

2. Description of the Related Art For example, with respect to a pressure-resistant part of a nuclear power plant, during a regular inspection, an inspection is carried out during a service period to confirm its soundness, and a leak detection means imposed as a design premise is currently 1 gpm. Is designed to be able to detect leaks within one hour, but in order to further improve plant reliability and stable operation, it is necessary to detect a smaller amount of leaks in a shorter time than the current situation and evaluate the leak position. It is important to do.

[0003] From this point of view, a conventional leak detection technique is to detect a leak by detecting a sound generated at the time of the leak or an increase in radiation level.
The E (acoustic emission) method, the microphone method, and the radiation method are typical.

[0004]

Among the conventional leak detection techniques as described above, in the AE method, the leak position can be evaluated in principle, but the accuracy is affected by external noise during plant operation. . In addition, it is difficult to immediately evaluate the leak position using the microphone method or the radiation method.

In view of the above prior art, the present invention is an optical type which can detect less leakage in a shorter time than the current state without being affected by disturbance during plant operation and can immediately evaluate the leakage position. It is an object of the present invention to provide a leak detection device.

[0006]

In order to achieve the above object, the present invention is directed to a moisture absorbing member which is attached to a cylindrical member adjacent to a leak detection target portion , wherein the cylindrical member is Perimeter
A substantially ring-shaped member in contact with the surface and a cutout
And a moisture absorbing material formed substantially in a ring shape.
The first magnet fixed to the outer peripheral surface of the first member and coupled to be openable and closable
The stone and the notch are fixed to each other and are attracted to each other by magnetic force
A moisture absorbing member having second and third magnets , a light source in a narrow wavelength range that generates light having a wavelength included in the absorption band of water, and an optical coupler optically connected to the light source; A first optical fiber having a proximal end connected to the optical coupler and a distal end connected to the moisture absorbing member, and a proximal end connected to the optical coupler and transmitting a reflected light from the moisture absorbing member to the distal end. Optical fiber for transmitting to the section, an image sensor provided opposite to the tip of the second optical fiber, and an image of the tip of the second optical fiber taken by the image sensor And an image processing analysis device for detecting the occurrence of leakage.

[0007]

According to the present invention having the above construction, a light beam having a wavelength included in the absorption band of water emitted from the light source is transmitted by the first optical fiber and irradiated on the moisture absorbing member, and the reflected light beam at this time is irradiated. Is transmitted again to the optical coupler by the first optical fiber. Further, the reflected light beam is
Is transmitted to the tip of the optical fiber. Thereafter, the tip of the second optical fiber is imaged by an image sensor, and the image at this time is subjected to image processing by an image processing / analyzing device, and the amount of reflected light is obtained.

[0008] At this time, if water is leaking in any of the leak detection target portions, the degree of squeezing of the moisture absorbing member attached to the leak detection target portion is greater than that of the other moisture absorbing members, and thus the image processing is performed. The light quantity of the light beam reflected from the obtained moisture absorbing member is lower than the light quantity of the reflected light ray from the other moisture absorbing members. From this, it is detected that a leak has occurred in the leak detection target section.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an explanatory diagram showing the configuration of the leak detecting device according to the present embodiment. As shown in the figure, the leak detecting device according to the present embodiment includes a plurality of moisture absorbing members including the moisture absorbing members 1, 2, 3, a plurality of waveguide type optical fibers 4, which are first optical fibers, and an optical coupler 5. , A light source 6, a plurality of optical fibers 7 as a second optical fiber, an image pickup tube 9 as an image pickup device,
An image processing / analyzing device 10, an alarm device 11 serving as a notification unit, and a monitor 12 are provided.

The light source 6 is a light source that generates a light beam, which is infrared light having a wavelength near 1.94 μm in the water absorption band. The optical coupler 5 is interposed between the light source 6 and the plurality of waveguide-type optical fibers 4 and the optical fiber 7, and transmits the light emitted from the light source 6 to the waveguide-type optical fiber 4. Then, the reflected light beam is transmitted to the optical fiber 7.

The plurality of waveguide type optical fibers 4 have their base ends connected to the optical coupler 5 and their front ends connected to the hygroscopic members 1, 2, 3 and other hygroscopic members, respectively. The above light beam is transmitted to irradiate each moisture absorbing member, and the reflected light beam at this time is transmitted again to the optical coupler 5.

A plurality of moisture absorbing members including the moisture absorbing members 1, 2, 3 are connected to the distal end of the waveguide type optical fiber 4 as shown in FIG. It is attached around each of the through-hole nozzles 23 which are leak detection target portions provided on the upper part of the reactor vessel 24 which is a high-pressure vessel. The penetrating portion nozzle 23 and the reactor vessel 24 are joined by welding, and this is a portion where leakage may occur.

FIG. 3A is a front view of a partially broken moisture absorbing member, and FIG. 3B is a sectional view taken along line CC of FIG. 3A. As shown in both figures, the moisture absorbing member comprises a moisture absorbing material 29 and a magnet 3.
0. The hygroscopic material 29 is a substantially ring-shaped member that is in contact with the outer peripheral surface of the through-hole nozzle 23, and has a cutout portion 29a at one portion thereof. Also, the magnet 30 of the magnet 30
a is formed in a substantially ring shape, and is fixed to the outer peripheral surface of the hygroscopic material 29. The magnets 30b and 30c are fixed to the notches 29a of the hygroscopic material 29, and are attracted to each other by magnetic force. In addition, the magnet 30a is connected by a member 31 so as to be openable and closable. That is, as shown in FIG. 4, the moisture absorbing member can be opened right and left by separating the magnets 30b and 30c, so that it can be easily attached to and detached from a cylindrical member such as the through nozzle 23. .

As shown in FIG. 5 (enlarged view of a portion B in FIG. 3A), the waveguide type optical fiber 4 is connected so as to be embedded in a hygroscopic material 29. Therefore, as shown in the figure, the transmission light beam 26 transmitted by the waveguide type optical fiber 4 is applied to the reflection surface 25 of the hygroscopic material 29, and the reflected light beam 27 at this time is again transmitted to the waveguide type optical fiber. 4 transmitted.

The plurality of optical fibers 7 have their base ends connected to the optical coupler 5 and have a waveguide type optical fiber 4.
Are transmitted to the reflected light detection surface 8, which is the tip thereof.

The image pickup tube 9 has a wavelength of 1.94 μm in the water absorption band.
The imaging device has high sensitivity to light having a wavelength near m, and is installed to face the reflected light detection surface 8 at the tip of the optical fiber 4. The imaging tube 9 captures an image of the reflected light detection surface 8 and transmits the image at this time to the image processing analysis device 10. The image processing analyzer 10 performs image processing on the image transmitted from the image pickup tube 9 to obtain a digital value of the amount of the reflected light. As a result, when it is determined that a leak has occurred, the alarm device 11 and the monitor 12 notify the occurrence and location of the leak.

According to the above embodiment, after the light beam having a wavelength of about 1.94 μm in the absorption band of water emitted from the light source 6 is transmitted to the waveguide type optical fiber 4 via the optical coupler 5. Is transmitted to each moisture absorbing member by the waveguide type optical fiber 4, and the reflection surface 2 of each moisture absorbing material 29 is transmitted.
5 and the reflected light at this time is transmitted again to the optical coupler 5 by the waveguide type optical fiber 4.

Further, the reflected light beam is transmitted to the optical fiber 7 via the optical coupler 5 and transmitted to the reflected light detecting surface 8 at the tip of the optical fiber 7. Thereafter, the reflected light detection surface 8 is imaged by the imaging tube 8, and the image at this time is transmitted to the image processing analysis device 10. The image processing / analysis device 10 performs image processing on the image, and as a result, obtains a digital value of the amount of the reflected light.

At this time, when no leakage occurs in any of the through-hole nozzles 23, as shown in FIG. 6A, the brightness of the reflected light from the moisture absorbing members 1, 2, and 3, 1
The brightness of the reflected light rays from the light-absorbing members 4, 15 and other members has a certain variation with little difference between them. Therefore, as shown in FIG.
Digital value 16, 17, 18 of the amount of reflected light from 3
The digital value of the light amount of the reflected light beam from the other moisture absorbing member has a certain variation with little difference between them. Therefore, the average value 19 and the deviation 20 of these digital values are statistically calculated and stored.

Next, for example, if there is a leak at the through-hole nozzle 23 to which the moisture absorbing member 2 is attached, the moisture absorbing material 29 of the moisture absorbing member 2 absorbs the leaked water, and therefore, the moisture absorbing member 2 becomes unusable. The degree of squeezing increases as compared with the above-mentioned moisture absorbing member. 1.
Since a light beam having a wavelength of around 94 μm is included in the absorption band of water, the light beam reflected from the moisture absorbing member 2 becomes weaker than a case where there is no leakage due to the increase in the degree of tightening. Accordingly, as shown in FIG. 7A, the brightness of the reflected light from the moisture absorbing member 2 is lower than the brightness of the reflected light from the other moisture absorbing members. Therefore, as shown in FIG. 7B, the digital value of the light amount of the reflected light from the moisture absorbing member 2 is lower than the digital value of the light amount of the reflected light from the other moisture absorbing members.
The deviation 20 will be deviated.

Therefore, the image processing / analyzing device 10 judges that a leak has occurred in the penetrating nozzle 23 to which the moisture absorbing member 2 is attached, activates the alarm device 11, and causes the monitor 12 to use the penetrating nozzle 23. Indicates that a leak has occurred.

[0023]

As described above in detail with the embodiments, the present invention is an optical leak detecting device using a light ray having a wavelength included in an absorption band of water, and an external leak detecting device represented by the AE method. It is possible to detect a smaller amount of leakage without being affected by disturbance such as noise, and at the same time, to evaluate a leakage position. Therefore, it is possible to further improve the reliability of the plant and contribute to safe operation. In addition, the moisture absorbing member and the second magnet
It can be opened right and left by pulling it away from the third magnet
Can be easily attached to and removed from cylindrical members.
Can be removed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a leak detection device according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3A is a front view of a partially broken moisture absorbing member,
(B) is a sectional view taken along line CC of (a).

FIG. 4 is a diagram illustrating a state when a moisture absorbing member is opened.

FIG. 5 is an enlarged view of a portion B in FIG. 3;

FIG. 6 is a diagram showing digital values of the brightness and the amount of light reflected from each moisture absorbing member when there is no leakage.

FIG. 7 is a diagram illustrating digital values of the brightness and the amount of light reflected from each moisture absorbing member when leakage occurs at the penetration portion nozzle 23 to which the moisture absorbing portion 2 is attached.

[Explanation of symbols]

 1, 2, 3 moisture absorbing member 4 waveguide type optical fiber 5 optical coupler 6 light source 7 optical fiber 9 image pickup tube 10 image processing / analysis device 11 alarm device 12 monitor

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuo Kida 1-1-1, Wadazakicho, Hyogo-ku, Kobe-shi, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Kobe Shipyard (56) References JP-A-1-260339 (JP) JP-A-63-19598 (JP, A) JP-A-62-88932 (JP, A) JP-A-63-214637 (JP, A) JP-A-56-112627 (JP, A) (58) Surveyed field (Int.Cl. ⁶ , DB name) G01M 3/38 G01M 3/20 G21C 17/02

Claims (1)

(57) [Scope of request for utility model registration] 1. A moisture absorbing member attached to a cylindrical member adjacent to a leak detection target portion , wherein the moisture absorbing member is provided outside the cylindrical member.
A substantially ring-shaped member in contact with the peripheral surface and a cutout
A moisture absorbing material having a portion, and a
A first member fixed to the outer peripheral surface of the material and connected to be openable and closable;
The magnet and the magnet are fixed to the notch and are attracted to each other by magnetic force.
A moisture absorbing member having second and third magnets , a light source in a narrow wavelength range for generating light having a wavelength included in the water absorption band, and an optical coupler optically connected to the light source. A first optical fiber having a proximal end connected to the optical coupler and a distal end connected to the moisture absorbing member, and a proximal end connected to the optical coupler and transmitting reflected light from the moisture absorbing member. A second optical fiber for transmitting to the distal end, an image sensor provided to face the distal end of the second optical fiber, and a distal end of the second optical fiber captured by the image sensor. A leak detection device comprising: an image processing analysis device that performs image processing on an image and detects occurrence of leakage.