JPH10300625A - Leak inspection device and leak inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out a leak inspection in a short time and moreover carry out the identification of a leak portion accurately. SOLUTION: Respective outside devices 810 are installed in the upper parts of a pair of base pipes 305a, 305b connected to branch pipes 304, an inside device 830 is lowered to a fixed position within the base pipes 305 through cables 826 from take-up machines 814, and the insides of the base pipes 305 and the branch pipes 304 are evacuated to the previously set vacuum of low level (such as 10<-2> Pa level) by vacuum exhausters 812. The travel device 821 of the inside device 820 and the take-up machines 814 of the outside devices 810 are operated by remote operation controllers 811, and leak detectors 824 are moved to a leak inspecting portion. The expansion feature of a semifinished seal device 822 is operated by the control from a remote operation controller, and a metal sheet is expanded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak inspection apparatus for inspecting whether there is a leak in a pipe by moving the inside of the pipe by remote control, and a leak inspection method using the apparatus.

[0002]

2. Description of the Related Art In nuclear power pipes and gas pipes buried underground that require high reliability, a defect detector that detects defects by ultrasonic inspection etc. has been installed to check the soundness of the pipes before. The development of the technology which moves the inspected device in the piping has been advanced. This type of inspection is performed around the welded portion, and the welding position is detected by a sensor. The main measurement items are appearance photographing with a TV camera, wall thinning measurement, and ultrasonic flaw inspection, all of which are performed in the atmosphere. In the development of the above technology, a drive mechanism for freely moving inside the bent pipe and a mechanism for performing operations such as welding and cutting in the pipe are also developed.

[0003] Regarding the vacuum technique, there has been reported a basic experiment in which a leak portion is provided in a part of a pipe in a vacuum, and a leak detector is operated to measure the detection sensitivity.

[0004]

By the way, the in-reactor piping in a fusion reactor is a highly reliable piping in which the existence of minute leaks is not allowed. If a leak is detected, the leak location is identified. Repair is required. It is difficult for humans to approach and inspect and repair the inside of the furnace both structurally and due to activation problems, and it is necessary to perform repairs by remotely controlling the inspection and repair equipment from outside the furnace.

For example, a blanket cooling pipe of a fusion reactor has a structure in which a blanket module having a long branch pipe is attached to a blanket body having a main pipe.
If a leak occurs in the weld between the main pipe and the branch pipe, high-pressure water in the cooling pipe leaks and the plasma does not ignite, so that a minute leak cannot be tolerated. In addition, since there are many welds between the main pipe and the branch pipe inside the pipe, it is not possible to identify the leak location only by evacuating the pipe at the pipe entrance outside the furnace and measuring the presence or absence of the leak.

As described above, it is difficult to apply an external vacuum method to a leak test in a blanket cooling pipe of a fusion reactor. Therefore, an internal vacuum method is used in which the inside of the pipe is evacuated to a certain degree, the outside is filled with a detection gas such as helium, and the gas leaking from the outside is detected. This internal vacuum method is a method of attaching a detector to the end of the pipe and checking whether there is a leak in the entire pipe, inserting a detector in the pipe and checking if there is a leak in a part of the pipe There is a way to check.

However, when a leak test of a blanket cooling pipe is performed by the internal vacuum method, (1) the conductance of one branch pipe is small and there are a plurality of branch pipes, so that a plurality of branch pipes are evacuated simultaneously. In the method of creating a required high vacuum state, evacuation takes a long time and a very long inspection period is required.

(2) Since a single blanket cooling pipe has a plurality of welds between the main pipe and the branch pipe, there is a possibility that the sensitivity may deteriorate due to the influence of the surrounding leak. Location identification becomes difficult.

There is a problem that

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a leak inspection apparatus and a leak inspection apparatus capable of performing a leak inspection in a short time and accurately identifying a leak location. An object of the present invention is to provide an inspection method.

[0011]

Means for Solving the Problems To achieve the above object, a first means is a leak inspection apparatus which moves to an arbitrary position in a pipe by remote control and detects the presence or absence of a leak at the arbitrary position. One pair is inserted into the pipe to form an inspection space by dividing the inside of the pipe into a predetermined width, and seal so that a predetermined differential pressure is maintained between the inspection space and the other space. Seal means, exhaust means for exhausting the inspection space, leak detection means for detecting the presence or absence of leak gas in the inspection space, and the seal means, the exhaust means and the leak detection means being integrally movable. Connection means for connection.

In this case, the leak detecting means is preferably provided in the inspection space, and the inspection space is set at a lower pressure than the space in the pipe other than the inspection space. Further, as the sealing means, for example, a metal sheet formed in an umbrella shape may be used, and a configuration may be made such that the outer edge of the metal sheet and the inner wall of the pipe are sealed. The outer edge of the metal sheet is preferably pressed against the inner wall of the pipe by pressing means, and an exhaust means is preferably provided on the inspection space side of the sealing means.

The second means is a leak inspection apparatus for detecting the presence or absence of a leak at an arbitrary position in a pipe by moving the pipe to an arbitrary position in a pipe by remote control, wherein only a small flow rate flows between the pipe and the inner wall of the pipe. It is formed in a shape like
A box movably inserted into the pipe, exhaust means for exhausting a space in the box, and a leak detecting leak gas flowing into the box to detect the presence / absence of a leak at the moving position of the box And a detecting means.

In this case, an exhaust means is provided in the box, and the inside of the box is exhausted by the exhaust means to make the pressure in the box lower than the pressure in the space outside the box. Further, a conduit for guiding gas outside the box body may be provided in the leak detecting means, and the presence or absence of a leak may be inspected by detecting the type of the gas.

The third means inserts the leak inspection device in the first and second means into a pipe, moves along the pipe to detect the presence or absence of a leak gas, and determines whether or not the leak gas is present. It is characterized by identifying the position.

An object to be identified is, for example, a blanket pipe of a fusion reactor, and a leak inspection device moves in a pair of mother pipes connected to both ends of a branch pipe of the blanket pipe while maintaining substantially the same level. The space between the pipes may be limited to inspect for the presence or absence of a leak, or one of the mother pipes may be closed at the end and moved in the other unclosed mother pipe. The inspection may be performed for each module of the blanket.

According to the first means, a pair of sealing means for sealing so as to maintain a predetermined differential pressure between the inspection space and the other space is moved, and the inside of the inspection space is exhausted. The leak detection means detects the presence or absence of leak gas flowing into the inspection space in a higher vacuum state, so that not only the space to be in a high vacuum state can be smaller but also the position of the inspection space can be specified, The inspection can be performed in a short time, and the leak position can be accurately identified.

Further, if the inspection space is set to a lower pressure than the space inside the pipe other than the inspection space in the first means, the leak gas flows into the inspection space due to the differential pressure between the inside and outside of the inspection space. I can do it. Further, if the sealing means is formed of a metal sheet formed in an umbrella shape, and a seal is formed between the outer edge of the metal sheet and the inner wall of the pipe, the required sealing function is exhibited by the metal sheet. In addition, it is possible to easily bend even in a curved pipe portion, whereby a leak test can be reliably performed regardless of the curvature shape of the pipe. Further, by providing means for pressing the outer edge of the metal sheet against the inner wall of the pipe, and by pressing the outer edge of the metal sheet against the inner wall of the pipe, the inspection space can be set at an arbitrary position.

According to the second means, the leak inspection apparatus is provided
A box that is movably inserted into the pipe and has a shape such that only a small flow rate flows between the pipe and the inner wall of the pipe; an exhaust unit that exhausts the inside of the box; By including the leak detecting means for detecting the presence or absence of a leak at the moving position, it is possible to further reduce the exhaust space as compared with the case where the inspection space is formed by the sealing means as described above. ,
Inspection time can be reduced. Further, in the second means, the pressure difference between the inside and the outside of the box can be maintained by providing a thin conduit for guiding the gas outside the box to the leak detection means, and the detection sensitivity can be reduced by reducing the pressure inside the box. And the gas from outside the box body can be reliably guided to the leak detection means side.

According to the third means, the leak inspection device is inserted into the pipe, moved along the pipe to detect the presence or absence of the leak gas, and the leak position is identified by the position where the leak gas is detected. Therefore, the leak position can be accurately identified in a short time. In addition, if the leak inspection device is moved while maintaining the same level in a pair of mother pipes connected to both ends of the branch pipe of the blanket pipe of the fusion reactor,
The leak test of the outgoing mother pipe and the return mother pipe can be performed simultaneously, and the inspection time can be shortened. The leak inspection device is connected to a pair of mother pipes connected to both ends of the branch pipe of the blanket pipe. If the end of one of the mother pipes is closed and the inside of the other mother pipe that is not closed is moved, a leak test can be performed after a sealed space is reliably formed. further,
If an inspection is performed for each module of the blanket by the leak inspection device, the presence or absence of a leak can be detected for each module.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 is a schematic view showing a state of a leak test of a mother tube and a branch tube of a blanket module of a fusion device according to a first embodiment of the present invention, and FIG. FIG. 3 is a longitudinal sectional view of one side showing a cross-sectional structure of a fusion device having a cooling pipe, FIG. 3 is a view showing a connection state between a main pipe and a branch pipe of a blanket module, and FIG. It is a principal part perspective view.

As shown in FIG. 2, the fusion device 100 includes a vacuum vessel 200, a blanket 300 inside the vacuum vessel 200 for extracting the thermal output of the plasma 1,
A toroidal magnetic field coil 400 for enclosing the plasma 1 inside the blanket 300 of the vacuum vessel 200 outside the vacuum vessel 200, and an air-core current transformer coil 500 provided inside the toroidal magnetic field coil 400
, A plasma control coil 600 provided on the outer periphery of the toroidal magnetic field coil 400, and a storage container 700 containing these.

A vertical port 201,
Each port of the horizontal port 202 and the exhaust port 203 is provided, and the inside of the container is maintained at a predetermined vacuum state. The vertical port 201 has the blanket 3
00 cooling pipes 301 are introduced and led out. Also,
As shown in FIG. 3, the blanket 300 includes a large number of blanket modules 302 and a blanket module mounting plate 303 to which the modules are mounted behind these modules. Inside the blanket module 302, branch pipes 304 are piped at a high density as shown in FIG.
It is connected to the mother pipe 305 arranged on the side.

Since such a fusion device is known, a detailed description of its structure and functions will be omitted.

The blanket module 302 thus constructed is connected to a branch pipe 304 as shown in FIGS.
Are connected to the mother pipe 305 by welding. At this time, since the main pipe 305 and the branch pipe 304 are each installed after undergoing a sufficient inspection outside the furnace, the main part where leakage occurs is at the welded portion 306. Therefore, these welded portions 306 are main leak inspection target portions.

As shown in FIG. 1, the leak inspection apparatus 800 basically comprises an extra-tube device 810 and an in-tube device 820. The extraluminal device 810 includes the remote control 81
1, a vacuum exhaust device 812, a leak measuring device 813, a winding device 814, and the like. The in-pipe device 820 is surrounded by a pair of traveling devices 821, a plurality of semi-perfect sealing devices 822 which are located inside the traveling devices 821, and are arranged in plurals so as to surround a leak inspection point. It consists of a vacuum pump 823 and a leak detector 824 installed in the space. The extra-tube device 810 and the in-tube device 820 are connected by a cable 826 via a support 825, and each element sandwiched between both traveling devices 821. Also cable 8
26. The semi-perfect sealing device 822
The sealing means for sealing so that a predetermined pressure difference can be maintained, the vacuum pump 823 for the exhaust means, and the leak detector 82
4 constitutes a leak detecting means, and the cable 826 constitutes a connecting means. Here, the reason why the sealing means is called a semi-perfect sealing device 822 is that it is not necessary to completely seal, and it is sufficient if the sealing means has a sealing function capable of holding a predetermined differential pressure.

As shown in FIG. 5, the semi-perfect sealing device 822 folds a metal sheet 827 such as an undivided soft indium sheet, and expands the metal sheet 827 in the radial direction. Inner wall 30
5c and the inner wall 305c of the main pipe and the metal sheet 827.
Is very small conductance between the outer edge 827a and the outer edge 827a. Instead of the metal sheet 827, a glass sheet sprayed with a metal powder on a glass cloth or a metal sheet vapor-deposited on the glass sheet surface can be used. As such a sealing means, any structure can be used as long as the structure does not generate high stress when the diameter increases and does not cause cracking. Therefore, it is also possible to adopt a mechanism like an umbrella bone as the expansion mechanism 828 and to attach the above-mentioned sheet to the umbrella bone. The reason why the indium sheet is used in this embodiment is that the sheet is soft and has good vacuum holding performance.

The leak inspection apparatus 80 thus configured
0, a pair of mother pipes 305a, 305a,
An extra-tube device 810 is installed on each of the upper portions of the in-pipe device 305 b via the cable 826 from the winding device 814.
0 is lowered to a predetermined position in the main pipe 305 and the apparatus stands by. Therefore, the mother pipe 305 and the branch pipe 3 are
The inside of the chamber 04 is evacuated to a preset low level of vacuum. When the evacuation is performed to a previously set low degree of vacuum (for example, about 10 ⁻² Pa), the traveling device 821 of the in-pipe device 820 and the winding device 814 of the out-of-pipe device 810 are operated by the remote control controller 811. Then, the leak detector 824 is moved to the leak inspection location. When the movement is completed, the expansion mechanism 828 of the semi-perfect sealing device 822 as shown in FIG.
Press and expand. As a result, the space sandwiched between the two metal sheets 827 is isolated from the other tube space 830, and an inspection space 829 is secured therebetween.

When the inspection space 829 is secured, the vacuum pump 823 located in the inspection space 829 is operated to evacuate the inspection space 829, and the pressure in the inspection space 829 is reduced to, for example, a vacuum of about 10 ⁻⁴ Pa. Set to state and leak detector 8
24 performs a leak gas detection operation. In this embodiment, the vacuum pump 823 is arranged inside the umbrella-shaped portion of the metal sheet 827 as shown in FIG. 5, and the inside is on the low pressure side (high vacuum side) and the outside is on the high pressure side (low vacuum side). )It has become.

The leak gas is made of helium gas filled in the vacuum vessel 200, and the leak detector 824 detects the presence or absence of the helium gas, and transmits it as an electrical signal to the measuring device 813 via the cable 826, 81
In step 3, the leak location is identified. The helium gas is set at a pressure higher than at least the pressure of the space 830 in the pipe, and if a defect such as a crack occurs in the welded portion 306, the helium gas can flow into the pipe from outside the pipe. Here, helium gas is used as the leak gas,
Other inert gases can be used similarly.

The remote operation is optimally performed by the main pipe 305 and the branch pipe 30.
4 is performed such that only one of the welds 306 with No. 4 is included in the inspection space 829. In the example shown in FIG. 1, the semi-perfect sealing device 8 is provided only in the mother pipe 305a on the outgoing side.
Since a closed space cannot be created by operating the nozzle 22, a similar device is installed in the mother pipe 305 b on the return side, the semi-perfect sealing device 822 is operated, and a leak test is performed for each blanket module 302. Like that. At this time, if the leak inspection is performed simultaneously on the going side and the return side, the inspection time can be reduced by half as compared with the case where the inspection time is performed one by one.

<Second Embodiment> FIG. 6 is a sectional view showing a schematic configuration of a leak inspection apparatus according to another embodiment, and FIG. 7 is a schematic diagram showing a leak inspection state. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

[0034] Leak inspection apparatus 900 according to this embodiment.
Is used to connect a pair of semi-perfect seal devices 822 to one box body 901.
It is configured in place of. The box body 901 is the mother pipe 305
Is small enough to move through the inside of
The outer shape is set so that the conductance becomes very small between the main pipe 305 and the main pipe 305 by the cable 825 and the traveling device 821. Inside the box 901, a vacuum pump 823 and a leak detector 824 are installed. From the conduit 902 which penetrates the box 901 and protrudes in a direction perpendicular to the longitudinal direction of the mother pipe 305, the box 9 is connected to the leak detector 824.
A gas other than 01 can be introduced.

The parts not particularly described are the same as those in the first embodiment.
The configuration is the same as that of the first embodiment.

The leak inspection device 90 thus configured
7, the extra-tube devices 810 are respectively installed above the mother pipes 305a to which the branch pipes 304 are connected as in the first embodiment as shown in FIG.
6, the in-pipe device 820 is lowered to a predetermined position in the mother pipe 305a and stands by. Therefore, the inside of the mother pipe 305a and the branch pipe 304 is evacuated to a preset low level of vacuum by the vacuum exhaust device 812. When the evacuation is performed to the previously set low level of vacuum (for example, about 10 ⁻² Pa), the remote control 81
1, the traveling device 821 of the in-pipe device 820 and the winding device 814 of the out-of-pipe device 810 are operated, the box 901 stops at the welded portion 306 between the mother pipe 305 and the branch pipe 304, and the conduit 902 is connected to the branch pipe 304. To face. In this state, the inside of the box 901 is evacuated by driving the vacuum pump 823. As a result, the inspection space 829 in the box 901 is replaced with the other tube space 83.
When the pressure becomes lower than 0 (high vacuum degree) and becomes a vacuum state of, for example, about 10 ⁻⁴ Pa as in the first embodiment, the leak detection by the leak detector 824 starts. in this case,
Gas flows from the other pipe space 830 through the conduit 902 due to the pressure difference between the inside of the box and the outside of the box. Leak detector 824
Then, the presence or absence of a leak gas (helium gas) in the inflowing gas is detected, and transmitted to the leak measuring device 813 as an electric signal via the cable 825 in the same manner as described above.

At this time, since the position of the conduit 902 is grasped by the remote control unit 811, if a leak gas is detected, the connection position of the detected branch pipe 304, that is, the leak point can be immediately identified.

In this embodiment, the box 901 constitutes a semi-perfect sealing device, and the inside of the box 901 is set as the inspection space 829 to perform the leak inspection. It will be easy. In addition, since the capacity of the inspection space 829 is significantly smaller than that of the first embodiment, the driving time of the vacuum pump 823 for achieving a high vacuum state is shortened, and the inspection time can be significantly reduced. it can.

In this embodiment, the return-side mother tube 3
05b is closed by a blind plate 307 to form a closed space.

[0040]

As apparent from the above description, the present invention has the following effects.

That is, the space for the high vacuum state can be reduced, and the position of the inspection space can be specified. Therefore, the inspection can be performed in a short time, and the leak position can be accurately identified.

Further, since the sealing means is formed of an umbrella-shaped metal sheet and is sealed between the outer edge of the metal sheet and the inner wall of the pipe, it is possible to easily follow the bending of the pipe. In addition, the leak test can be reliably performed regardless of the shape of the pipe, and the test space can be set at an arbitrary position.

A box which is formed in such a shape that only a very small flow rate flows between the inner wall of the pipe and is movably inserted into the pipe, an exhaust means for exhausting the inside of the box, and an inflow into the box. Since there is provided a leak detecting means for detecting a leak gas to detect the presence or absence of a leak at the moving position of the box,
As compared with the case where the inspection space is formed by the sealing means as described above, the space for exhausting can be further reduced, and the inspection time can be shortened accordingly.

Furthermore, even in a piping having a large number of welds such as a blanket pipe of a fusion reactor and having a complicated shape, a leak inspection can be performed by freely setting an inspection space, and the leak location can be identified in a short time. Can be performed with high accuracy.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration and an inspection state of a leak inspection apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a schematic configuration of a nuclear fusion device to which the present invention is applied.

FIG. 3 is a diagram showing a schematic configuration of a blanket module of a fusion device in which a leak test is performed.

FIG. 4 is a partially sectional perspective view showing the structure of the blanket module of FIG. 3;

FIG. 5 is a diagram showing an operation state of the semi-perfect sealing device according to the first embodiment.

FIG. 6 is a schematic configuration diagram illustrating a main part of a seal inspection device according to a second embodiment.

FIG. 7 is a diagram illustrating a schematic configuration and an inspection state of a seal inspection device according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plasma 200 Vacuum container 300 Blanket 301 Blanket cooling piping 302 Blanket module 303 Blanket module mounting plate 304 Branch pipe 305, 305a, 305b Mother pipe 800 Leak inspection device 810 External device 811 Remote operation control device 812 Vacuum exhaust device 813 Leak assumption device 814 Take-up device 820 In-tube device 821 Traveling device 822 Semi-perfect sealing device 823 Vacuum pump 824 Leak detector 826 Cable 829 Inspection space 900 Leak inspection device 901 Box body 902 Conduit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Hiroshi Taguchi, Inventor Hiroshi Taguchi, 801 Mukaiyama, Naka-cho, Naka-gun, Ibaraki Pref. １ The Japan Atomic Energy Research Institute Naka Research Laboratory

Claims (15)

[Claims] 1. A leak inspection apparatus for detecting the presence or absence of a leak at an arbitrary position in a pipe by moving the pipe to an arbitrary position by remote control, wherein the pipe is inserted into the pipe, and the pipe is divided into a predetermined width. A pair of sealing means for forming an inspection space and sealing so that a predetermined differential pressure is maintained between the inspection space and the other space; an exhaust means for exhausting the inspection space; Leak detecting means for detecting the presence or absence of leak gas flowing into the inspection space; and connecting means for integrally and movably connecting the sealing means, the exhaust means and the leak detecting means. Leak inspection equipment. 2. The leak inspection apparatus according to claim 1, wherein said leak detection means is provided in said inspection space. 3. The leak inspection apparatus according to claim 1, wherein the inspection space is set at a lower pressure than a space in the pipe other than the inspection space. 4. The leak inspection apparatus according to claim 1, wherein said sealing means is formed of an umbrella-shaped metal sheet, and is sealed between an outer edge of said metal sheet and an inner wall of a pipe. 5. The apparatus according to claim 4, further comprising means for pressing an outer edge of said metal sheet against an inner wall of said pipe.
The leak inspection device as described. 6. The leak inspection apparatus according to claim 1, wherein the exhaust unit is provided on the inspection space side of the sealing unit. 7. A leak inspection device for detecting the presence or absence of a leak at an arbitrary position in a pipe by moving the pipe to an arbitrary position in a pipe by a remote control, wherein the leak inspection apparatus has a shape such that only a small flow rate flows between the pipe and the inner wall. A box formed and movably inserted into the pipe by remote control; an exhaust unit for exhausting a space in the box; and a leak detecting unit for detecting the presence or absence of leak gas flowing into the box. A leak inspection device comprising: 8. The leak inspection apparatus according to claim 7, wherein said exhaust means is provided in said box. 9. The leak inspection apparatus according to claim 7, wherein said leak detection means is provided in said box. 10. The leak inspection apparatus according to claim 9, wherein the leak detection means includes a conduit for guiding gas outside the box. 11. The leak inspection apparatus according to claim 7, wherein the space inside the box is set at a lower pressure than the space outside the box by the exhaust means. 12. The leak inspection apparatus according to claim 1 is inserted into a pipe, moved along the pipe to detect the presence or absence of a leak gas, and leaked according to the position where the leak gas was detected. A leak inspection method characterized by identifying a position. 13. The apparatus according to claim 13, wherein the pipe is a blanket pipe of a fusion reactor, and the leak inspection device moves at a substantially same level in a pair of mother pipes connected to both ends of a branch pipe of the blanket pipe. 13. The leak inspection method according to claim 12, wherein: 14. The pipe is a blanket pipe of a fusion reactor, and the leak inspection device closes one end of a pair of mother pipes connected to both ends of a branch pipe of the blanket pipe. The leak inspection method according to claim 12, further comprising moving the inside of the other mother pipe that is not closed. 15. The apparatus according to claim 12, wherein the pipe is a blanket pipe of a fusion reactor, and the leak inspection apparatus performs an inspection for each module of the blanket.
15. The leak inspection method according to any one of items 14 to 14.