JP3349655B2 - Method and apparatus for inspecting leak position of thin tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a leak position of a thin tube for inspecting a leak portion generated in a narrow tube having a small inner diameter and a long shape, and to an apparatus therefor. The present invention relates to a method and an apparatus for inspecting a leak position of a thin tube suitable for inspecting a cooling water channel.

[0002]

2. Description of the Related Art Generally, a nuclear fusion device is provided with a toroidal coil or the like for confining plasma in a vacuum vessel. Water is circulated inside the toroidal coil for cooling. A cooling water channel is formed.

In such a toroidal coil, it is necessary to inspect whether or not a water seepage portion exists in the cooling water channel, that is, whether or not a water seeping portion exists on the peripheral wall of the thin tube forming the cooling water channel. However, since the thin tube is buried in the toroidal coil, it is not possible to inspect the oozing portion from the outside of the thin tube. Therefore, in the conventional inspection method, after completely draining the water in the cooling water channel, a specific gas is injected into the cooling water channel and pressurized, the pressure fluctuation of the gas is monitored, and when the gas pressure decreases, It was determined that there was a water seepage on the peripheral wall of the thin tube.

[0004]

In the above-mentioned prior art, however, it is only necessary to inspect whether or not there is a seepage portion of water on the peripheral wall of the thin tube forming the cooling water passage.
Even if the presence of a bleeding part could be checked, the position of the bleeding part could not be specified. Moreover, in the conventional gas pressurization, not only the pressure fluctuates due to a change in temperature, but also the measurement accuracy decreases as the volume of the cooling water channel increases, and thus there is a problem in reliability.

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, even if a water oozing portion occurs in a thin tube forming a cooling water channel, the position of the water oozing portion can be specified without fail, and the temperature change can be achieved. Another object of the present invention is to provide a thin-tube leak position inspection apparatus capable of accurately performing the above-described method regardless of the volume of the cooling water passage or the volume of the cooling water passage. is there.

[0006]

According to the method of the present invention,
A method for inspecting a bleeding portion present on a peripheral wall of a circular tube forming a cooling water passage and forming an annular shape, comprising the following steps: A) Filling an empty cooling water passage with a test gas pressurized. The test gas is extruded into the oozing part existing on the peripheral wall of the capillary and the surrounding material surrounding the conductor, B).
Next, after removing the inspection gas in the cooling water channel, C) the inspection gas impregnated into the oozing portion of the peripheral wall of the thin tube and the surrounding material is drawn into the cooling water channel, and the extracted inspection gas is discharged. By flowing the carrier gas into the cooling water channel, a state is created which is present only upstream but not upstream of the draining portion. D) While moving the preformed suction probe along the cooling water channel, the suction is performed. The probe sucks the gas in the cooling water passage. E) When the test gas existing only on the downstream side from the bleeding portion in the cooling water passage is detected from the sucked gas, the suction in the cooling water passage is performed. The present invention is characterized in that a bleeding portion of a peripheral wall of a thin tube is specified based on a moving amount of a probe.

Further, the present invention is an apparatus for inspecting a bleeding portion present on a peripheral wall of a narrow tube forming a cooling water passage and forming an annular shape, comprising: a gas supply source of an inspection gas and a carrier gas; The gas from the gas supply source is supplied to and discharged from the cooling water channel of the thin tube, and the flow rate and the pressure of the gas flowing through the cooling water channel are adjusted, so that the water present on the peripheral wall of the thin tube from the cooling water channel. Means for causing the inspection gas to be extruded into the portion and the surrounding material surrounding the conductor, and causing the extruded inspection gas to be present only in the water bleeding portion and the downstream side in the cooling channel, and moving in the cooling channel. A suction means for sucking in the gas in the cooling water passage while inspecting means for measuring a test gas existing only on the downstream side of the water leaking portion in the cooling water passage among the sucked gas. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIGS. 1 to 5 show an embodiment in which an embodiment of a leak inspection apparatus for carrying out the method of the present invention is applied to a toroidal coil of a nuclear fusion apparatus.

Before describing the leak inspection apparatus, a toroidal coil 100 indicated by a broken line in FIG. 1 will be described briefly. The toroidal coil 100 is provided in a pressure vessel (not shown) along the torus direction. As shown in FIG. 2 and a partially enlarged FIG. 3 of the toroidal coil 100, a plurality of coil conductors 103 are laminated on a non-magnetic coil case 101 via a ground insulating material 102. The surface of each of the coil conductors 103 is an interlayer insulator 104.
Square pipe 1 covered with
05 is buried, and the inside of the square pipe 105 is
6.

Although not shown in detail, the cooling water passage 106 is formed in a multiple curved shape as shown in FIG. 1 by communicating with the inside of the cooling water passage of each coil conductor 103.
The cross section of the cooling water passage 106 is, for example, about 5 × 15 mm in cross section, depending on the size of the nuclear fusion device.
Cool 00.

The leak position inspection apparatus according to the embodiment is roughly divided into a gas supply source and a gas supplied and discharged from the gas supply source to and from the cooling water passage 106, while the flow rate and the flow rate of the gas flowing through the cooling water passage are changed. Supply / discharge means for adjusting pressure, and cooling water channel 1
Inspection means for inhaling and measuring the inspection gas in 06.

More specifically, in FIG. 1, the gas supply source is a helium gas supply source 3 as a test gas,
The cooling water passage 106 is dried and functions as a carrier gas for helium gas.

The above-mentioned supply / discharge means is used for cooling water passage
06 and a gas connection pipe 4 connected to the end (end) of the cooling water channel 106.
And a vacuum pump 5 connected to the gas connection pipe 4. Branch pipes 1a and 1b are provided at an upstream portion of the gas supply pipe 1, and a nitrogen gas supply source 2 and a helium gas supply source 3 are connected to these branch pipes 1a and 1b.

A flow adjusting valve 6 for adjusting the flow rate of the nitrogen gas supplied from the nitrogen gas supply source 2 and a flow meter 7 are provided at an intermediate position of the branch pipe 1a. An on-off valve 8 for supplying or stopping the helium gas from the helium gas supply source 3 to the downstream side is provided at an intermediate position of the branch pipe 1b. In the gas supply pipe 1, branch pipes 1a, 1b
Further downstream, there is provided a compound meter 9 capable of measuring the pressure in the cooling water passage 106 between a negative pressure and a positive pressure.

The vacuum pump 5 is for evacuating the inside of the cooling water passage 106 and is driven as required. An opening / closing valve 10 is provided at an intermediate position of the gas exhaust pipe 4, and a vacuum gauge 11 for measuring a vacuuming state of the vacuum pump 5 is provided.

On the other hand, the inspection means includes a suction probe 12 moving in the cooling water passage 106 and the suction probe 1.
Inspection pump 1 that sucks gas in cooling water passage 106 from 2
3 and a measuring device 14 for detecting helium gas discharged from the pump. The suction probe 12 is inserted into the cooling water passage 106 from the opening / closing valve 15 side provided at the distal end side of the gas supply pipe 1, and serves to suck the gas in the cooling water passage 106 while moving inside the cooling water passage 106. Therefore, the tubular body is extremely thin so that it can be inserted into the cooling water passage 106, and has flexibility so that it can move even at a curved portion of the cooling water passage 106 having a curved shape.
For example, while having a thin and extremely thin cylindrical body,
Formed to be longer than the length of the cooling water passage 106 (inner diameter 0.5
(φ, length 50 m).

The inspection pump 13 adsorbs a gas other than helium gas, which is an inspection gas, and passes only helium gas as it is. Therefore, a special adsorbent for adsorbing a gas other than helium gas therein is used. Is provided. When detecting the helium gas discharged from the inspection pump 13, the measuring device 14 outputs and displays the helium gas in accordance with the detection signal, as indicated by the highest portion indicated by the solid line A in FIG. In this case, when the helium gas is detected by the measuring device 14, the position of the bleeding portion of the cooling water channel 1 (portion B in FIG. 4) is determined based on the length of the suction probe 12 with respect to the cooling water channel 1 at that time. That is, the bleeding portion of the square pipe 105 forming the cooling water channel 1 is specified.

This leak inspection apparatus is generally filled with a pressurized helium gas in a cooling water passage 106, and from the inside of the cooling water passage 106, a bleeding portion of each pipe 105 forming the same and its surroundings. The helium gas was extruded into the insulator and then unnecessary inspection gas in the cooling water passage 106 was removed, and then the water was extruded from the cooling water passage 106 into the oozing portion of each pipe 105 and the surrounding insulator. The helium gas is drawn into a water seepage portion in the cooling water channel 106 to be in a viscous flow state.
2 is moved in the cooling water channel 106 to suck gas into the suction probe, and the suction probe 12
When the helium gas staying in the cooling water passage 6 is detected, the water leaking portion of the cooling water passage 106 is specified based on the movement amount of the suction probe 12 in the cooling water passage 106.

Next, an embodiment of the method of the present invention will be described with reference to FIG. Prior to the inspection of the cooling water channel 1, the toroidal coil 10
After completely draining the water in the cooling water passage 106 (step 31), a preparation process required for inspection is performed.

That is, first, the end of the gas supply pipe 1 is connected to one end of the cooling water passage 106, and the gas exhaust pipe 4 is connected to the end of the cooling water passage 106.
06 is completely dried. In this case, the on-off valve 8 for helium gas and the on-off valve 15 for detection of the gas supply pipe 1 are respectively closed, while the flow control valve 6 of the gas supply pipe 1 and the on-off valve 10 of the gas exhaust pipe 4 are opened. Next, the inside of the cooling water passage 106 is dried by supplying nitrogen gas into the cooling water passage 106 from the nitrogen gas supply source 2 (step 32).

Thereafter, the on-off valve 6 is closed and the vacuum pump 5 is driven to evacuate the nitrogen gas in the cooling water passage 106 to completely remove the gas (step 3).
3). When the evacuation of the cooling water passage 106 is completed, the operation of the vacuum pump 5 is stopped. Whether or not the evacuation has been performed can be confirmed by monitoring the compound gauge 9 and the vacuum gauge 11.

After the evacuation, the cooling water passage 106
A helium gas as a test gas is supplied and pressurized (step 34). That is, while the on-off valve 8 of the branch 1b is opened, the on-off valve 10 of the gas exhaust pipe 4 is closed, and in this state, the helium gas supply source 3 supplies the pressurized helium gas into the cooling water passage 106 to fill it. Let it. This allows
When there is a water seepage portion on the peripheral wall of the square pipe 105 forming the cooling water channel 106, the helium gas in the cooling water channel 106 supplies helium gas to the water seepage portion of each pipe peripheral wall and the insulating portion on the outer peripheral side. It will be in the state of being pushed out. In this case, the pressurized helium gas is supplied to the cooling water passage 1
06 is maintained for about one hour as it is, so that it is surely pushed out of the cooling water passage 106 to the oozing portion of each pipe peripheral wall and the insulator on the outer peripheral side thereof. Thereafter, the on-off valve 8 of the branch pipe 1b is closed, and the on-off valve 10 of the gas exhaust pipe 4 is opened to reduce the pressure of the helium gas in the cooling water passage 106 to the atmospheric pressure.

Thereafter, the nitrogen gas is again supplied to the cooling water passage 106, and the helium gas in the cooling water passage 106 is replaced with nitrogen gas (step 35). In this case, the helium gas in the cooling water passage 106 is replaced with nitrogen gas by opening the flow control valve 6 of the branch pipe 1a and supplying nitrogen gas from the nitrogen gas supply source 2.

Therefore, by replacing the helium gas state with the nitrogen gas in the cooling water passage 106, unnecessary helium other than the helium gas extruded by the water bleeding portion of each pipe peripheral wall and the insulator in the cooling water passage 106. The gas will be exhausted.

Then, the suction probe 12 is connected to the cooling water channel 1.
In order to insert the suction probe into the gas inlet pipe 06, the on-off valve 15 of the gas supply pipe 1 is opened, and the tip of the suction probe 12 is inserted therein through a tool such as a probe joint (not shown) (step 36). In this case, a sealing material (not shown) is filled to prevent a gas from leaking due to a gap between the suction probe 12 and the on-off valve 15. Since the inspection pump 13 and the measuring device 14 are operated in advance, the suction probe 12 tries to suck the helium gas in the cooling water passage 106 when inserted from the on-off valve 15 side.
Since the inside of the cooling water channel is replaced with the nitrogen gas by the processing of the above step 35, there is no possibility that unnecessary helium gas is inhaled to cause a misdiagnosis of the inspection.

Next, the flow rate control valve 6 of the branch pipe 1a and the open / close valve of the gas exhaust pipe 4 are opened, and the nitrogen gas is supplied from the nitrogen gas supply source 2 into the cooling water passage 106. By operating the vacuum pump 5, the cooling water passage 10
The pressure is reduced so that the inside of the chamber 6 becomes a negative pressure (step 37). As a result, the helium gas that has been pushed out by the draining portion of the square pipe 105 and the insulator on the outer peripheral side thereof is drawn into the space of the cooling water passage 106.

At that time, the helium gas drawn into the cooling water passage 106 is not located upstream of the water seepage portion,
In order to be present only at the bleeding part and downstream,
The flow control valve 6 is adjusted to supply a desired amount of nitrogen gas to the cooling water channel 1.
06 to make the inside of the cooling water passage 106 into a viscous flow state (step 38).

As described above, when the helium gas is drawn out to the draining portion side in the cooling water passage 106 and is in a viscous flow state, detection of the helium gas is started (step 39). That is, the suction probe 12 is moved in the cooling water passage 106 so that the distal end of the suction probe 12 passes through the entire cooling water passage 106. In this case, since the suction probe 12 is flexible, the suction probe 12 can surely move even if the cooling water passage 106 is curved. The suction probe 12 may be moved slowly from the upstream side to the downstream side in order to surely suck the helium gas, and it is also preferable to return from the downstream side to the upstream side.

When the suction probe 12 moves, it is checked whether or not the measuring instrument 14 has detected helium gas (step 40). For example, when the suction probe 12 reaches the water bleeding part side in the cooling water channel 106 and helium gas as a test gas is sucked from the tip of the suction probe 12, the helium gas is inspected through the suction probe 12. When taken into the pump 13 and sent out to the measuring device 14, the output of the measuring device 14 is markedly increased as indicated by the portion B of the solid line A in FIG.

Therefore, since the helium gas is detected by the measuring device 14, the bleeding portion of the square pipe 105 forming the cooling water passage 106 is specified based on the feed length of the suction probe 12 to the cooling water passage 106 (step). 41). The inspection of the helium gas is performed in the cooling water channel 1
06 (step 42).
End the inspection.

In the method of the present invention, as described above,
In the case where there is a water seepage portion on the peripheral wall of the square pipe 105 forming the helium gas 06, the helium gas is once extruded into the water seepage portion of the square pipe peripheral wall and the insulator (surrounding material) on the outer periphery of the coil. Helium gas
When the suction probe 12 that has moved the cooling water passage 106 sucks helium gas in this state, the amount of movement of the suction probe 12 in the cooling water passage 106 is reduced. Since the position of the bleeding part of the cooling water channel is specified based on this, the position of the bleeding part can be known accurately. For this reason, compared to the conventional technology of monitoring the fluctuation of the gas pressure in the cooling water channel, the position of the water seepage portion can be specified more reliably, and the specified value can be specified regardless of the increase in the area of the cooling water channel or the temperature change. it can.

In FIG. 5, the suction probe 1
2 is only moved from one end (upstream) to the other end (downstream) of the cooling water passage 106. However, when specifying a bleeding portion, the suction probe 12 is moved from the opposite direction to the cooling water passage 106. They may move and check the location of the spill. That is, the gas exhaust pipe 4, the vacuum pump 5, and the like are connected to one end of the cooling water passage 106, and the gas supply pipe 1, the gas supply sources 2, 3, and the like are connected to the other end of the cooling water passage 106. By inserting and moving the suction probe 12 from the side, the position of the draining portion is confirmed. A broken line C shown in FIG. 4 indicates the output of the measuring device 14 when the suction probe 12 is detected by moving the suction probe 12 from the other end to the one end of the cooling water passage 106 in such a reverse connection state. . Performing such a check operation with the reverse connection is more effective because the accuracy of specifying the draining portion can be improved. Incidentally, the measurement accuracy at this time is determined by the cooling water passage 106
5.89 to 5.90 m from the upstream side (one end) of the sample, and could be measured with an accuracy of about 10 mm.

On the other hand, in the leak position inspection apparatus according to the embodiment, the gas from the gas supply source is cooled by the gas supply source including the helium gas supply source 3 and the nitrogen gas supply source 2 and the cooling water passage 106 of each pipe 105. While supplying and discharging to and from the water passage 106, the flow and pressure of the gas flowing through the cooling water passage 106 are adjusted, and the flow control valve 6 and the plurality of on-off valves 8.10.
5, a supply / discharge means comprising a vacuum pump 5 and the like, a gas in the cooling water channel is sucked while moving in the cooling water channel, and a part of the sucked gas is present on a water bleeding portion in the cooling water channel and on the downstream side. Inspection probe 1
2, since it is configured to include the inspection means including the inspection pump 13 and the measuring device 14, the above method can be performed accurately. Moreover, since the suction probe 12 is extremely thin and flexible, the suction probe 12 can surely move in a narrow tube having a small inside diameter and a curved line like the cooling water passage 106, and can perform a good function even in a narrow space. it can.

In the illustrated embodiment, the suction probe 12
Sucks helium gas, and the helium gas is
The position of the water seepage portion of the cooling water passage 106 can be obtained by calculation at the time of detection. Therefore, means for detecting the amount of movement of the suction probe 12 with respect to the cooling water channel 106, and when the measuring device 14 detects helium gas, calculates the position of the water seepage portion in the cooling water channel 106 based on the amount of movement of the suction probe 12. And means for performing the operation.

[0035]

As described above, according to the first aspect of the present invention, the cooling water channel is filled with the test gas pressurized, and the draining portion and the conductor existing on the peripheral wall of the thin tube are formed. To
Extrude the test gas with the surrounding surrounding material, and then
After removing the inspection gas in the cooling water channel,
Inspection gas soaked in the water seepage and surrounding material
To the cooling water channel and for the inspection
The gas is caused by flowing the carrier gas into the cooling channel.
And exists only downstream, not upstream
Condition, then the pre-formed suction probe
While moving the valve along the cooling channel,
The gas in the cooling water passage is sucked, and of the sucked gas,
It exists only downstream from the water seepage in the cooling channel.
When the test gas is detected,
Bleeding part of the capillary wall based on the amount of movement of the probe
Since so as to identify the partial position of's a water stain portion know exactly, to it water stains can be reliably identify the position of the portion, also identified without involving the increase or the temperature change of the area of the cooling water passage There is an effect that can be done.

According to the second aspect of the present invention, the gas from the gas supply source is supplied to and discharged from the gas supply source of the inspection gas and the carrier gas to the cooling water channel of the narrow tube, and the gas flows through the cooling water channel. The flow rate and pressure of the gas to be adjusted are adjusted, and from the inside of the cooling water channel, the test gas is pushed out to the oozing part existing on the peripheral wall of the thin tube and the surrounding material surrounding the conductor,
And a means for causing the extruded test gas to become viscous at a bleeding portion in the cooling channel, and sucking the gas in the cooling channel while moving in the cooling channel.
Since it is configured to include the inspection means for measuring the inspection gas at the water bleeding portion in the cooling water channel, there is an effect that the above method can be performed accurately.

[Brief description of the drawings]

FIG. 1 is a piping diagram showing an embodiment of a leak position inspection device for carrying out the method of the present invention.

FIG. 2 is an explanatory sectional view showing a part of a toroidal coil having a built-in cooling water passage;

FIG. 3 is an enlarged view of a main part of FIG. 2;

FIG. 4 is an explanatory diagram showing a measurement state of a measuring device.

FIG. 5 is a flowchart showing the method of the present invention in the order of steps.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Gas supply pipe, 2 ... Nitrogen gas supply source, 3 ... Helium gas supply source as inspection gas, 4 ... Gas exhaust pipe, 5 ... Vacuum pump, 6 ... Flow control valve, 7 ... Flow meter, 8, 10 , 1
5 ... open / close valve, 9 ... compound gauge, 11 ... vacuum gauge, 12 ... suction probe, 13 ... inspection pump, 14 ... measuring instrument.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Sasashima 3-1-1, Saimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant (72) Inventor Masaa Shimizu 801 Mukoyama, Nakamachi, Naka-gun, Naka-gun, Ibaraki Prefecture No. 1 in the Japan Atomic Energy Research Institute Naka Research Laboratory (72) Inventor Takashi Arai 801 in Mukaiyama, Naka-machi, Naka-gun, Naka-gun, Ibaraki Prefecture 1 in Japan Nuclear Research Institute Naka Research Laboratory (72) Inventor Kiyoshi Matsumoto Sachiko Hitachi, Ibaraki Prefecture No. 2-2 Hitachi Engineering Services Co., Ltd. (72) Inventor Masami Suzuki 3-2-1 Sayukicho, Hitachi City, Ibaraki Pref. Hitachi Engineering Co., Ltd. (56) References JP-A-4-145340 (JP, A JP-A-58-147628 (JP, A) JP-A-5-27649 (JP, A) JP-A-61-184437 (JP, A) 133602 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01M 3/20 G01M 3/02 G01M 3/04 G21C 17/025 GDF

Claims (2)

(57) [Claims] 1. A thin tube forming a cooling water passage and forming an annular shape.
This is a method to inspect the water seepage on the surrounding wall.
A) Inspection pressurized in the empty cooling water channel
Filled with cleaning gas and seeps on the peripheral wall of the capillary
Part andSurrounds the conductorPress the test gas with the surrounding material
B) Then, after removing the gas for inspection in the cooling water channel, C) soak into the oozing part of the peripheral wall of the thin tube and the surrounding material.
Inspection gas in the cooling water channelAnd pull out the
The test gas that flows out flows carrier gas into the cooling water channel.
By doing so, it is not upstream but downstream
Create a state that only exists in  D) In that state, cool the preformed suction probe
While moving along the water channel, the suction probe
Inhale the gas inside, E)A part of the sucked gas that oozes out in the cooling water channel
Only exists downstream from the minuteInspection gas detected
At this point, the amount of suction probe movement in the cooling
The feature is to identify the bleeding part of the capillary peripheral wall
Inspection method of the leak position of the thin tube to be used. 2. An apparatus for inspecting a bleeding portion existing on a peripheral wall of a narrow tube forming a cooling water passage and forming an annular shape, comprising: a gas supply source of an inspection gas and a carrier gas; On the other hand, while supplying and discharging the gas from the gas supply source, the flow rate and the pressure of the gas flowing in the cooling water channel are adjusted, and the water seeping portion and the conductor existing on the peripheral wall of the thin tube are surrounded from the cooling water channel. Means for extruding the inspection gas with the surrounding material, and causing the extruded inspection gas to be in a viscous flow state at a bleeding portion in the cooling channel, and a gas in the cooling channel while moving in the cooling channel. And a test means for measuring a test gas drawn into a water bleeding portion of the cooling water passage from the sucked gas.