JP2760712B2 - Flaw detector for double pipe structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flaw detector for detecting a surface defect generated in a cylindrical weld, for example, an improved BWR.
In the RIP nozzle weld at the lower part of the reactor pressure vessel
About the flaw detector for inspecting the heavy tube structure.

[0002]

2. Description of the Related Art A RIP nozzle of a reactor pressure vessel is formed by welding a pressure vessel and a casing in the middle of a through hole. As a method of inspecting the welded portion of the RIP nozzle, there is the following known technique. 1. Inspection method for reactor water circulation pump mounting welded part of nuclear reactor (Japanese Patent Laid-Open No. 57-168155) This known technique involves positioning a flaw detection head of a flaw detection device at a welding position on a central axis of a nozzle through hole, and then detecting a flaw by a drive device. The head is rotated to inspect the weld for defects.

[0003] In general, there are penetrant flaw detection, radiation flaw detection, ultrasonic flaw detection and the like as a method of flaw detection for a welded portion of a structure. 2. Penetrant testing apparatus (Japanese Patent Application Laid-Open No. 2-179441) This known technique is to apply a penetrating testing liquid by taking out a coated body from a vertically and rotatable flaw detection head, and then performing observation using a TV camera head. Inspection of the inner surface of the existing pipe by penetrant inspection.

[0004] 3. Inner surface penetration testing method (Japanese Patent Application Laid-Open No. 56-316)
26) According to this known technique, a penetrating liquid is impregnated into a defective portion of a narrow inner surface flaw detection portion of a flaw detection inspection object, and a defect indicating pattern appearing on a developed coating film is observed with an inspection device, so that accurate penetration of the narrow inner surface is performed. Inspection by flaw detection is performed.

[0005]

When the welded portion of the RIP nozzle is inspected from the back side of the through hole, an opening is provided below the RIP nozzle due to the restriction of the double pipe structure, and the double pipe structure is formed from the opening. It is necessary to insert a flaw detector into the gap between the inner pipe and the outer pipe to inspect the weld. However, the known technique 1 is an inspection method from the inside of the through hole, that is, from the inside of the inner pipe, and therefore cannot be applied to the inspection of the welded portion from the back side, that is, the gap between the inner pipe and the outer pipe having a double pipe structure.

The following problems exist when applying the known techniques 2 and 3 to the flaw detection inspection of the welded portion of the RIP nozzle. Known technique 2 is an inspection method for an inner surface of a pipe, and cannot be applied to inspection of a weld in a narrow structure.

The prior art 3 can cope with a narrow structure to some extent, but since the flaw detector has a tubular structure, the RIP
Accurate positioning with respect to the nozzle weld is difficult and flaw detection cannot be performed over the entire circumference of the cylindrical structure.

An object of the present invention is to perform a flaw detection test on a welded portion of an inner pipe of a double pipe structure from a gap between an inner pipe and an outer pipe.
An object of the present invention is to provide a flaw detector for a heavy pipe structure.

[0009]

[0010]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a method for manufacturing a vehicle, wherein a gap between an inner pipe and an outer pipe is narrow, at least one of the gaps is closed, and an access opening is formed in the outer pipe. A flaw detection head for performing a flaw detection test on the inner pipe welded part, wherein the flaw detection head performs the flaw detection test on the inner pipe welded part of the double pipe structure provided with the part. Positioning means for positioning the head through the access opening outside the welded portion of the inner pipe in the gap between the inner pipe and the outer pipe, wherein the positioning means operates the flaw detection device through the access opening. A belt for moving the head to a predetermined position is attached and when the flaw detection head is moved,
An arm forming a guide, and mounting and removing the arm
And a rotatable ring that can be used .

[0011]

[0012] Preferably, the arm and the rotary ring are configured in an articulated shape.

[0013] More preferably, the arm and the rotating ring have a structure that can be assembled and disassembled at the opening, or have a structure that has a plurality of nodes connected by pins and can be bent and stretched. Good.

Preferably, a rack for rotating the flaw detection head and the arm by an operation from the access opening is cut on an outer periphery of the rotating ring.

More preferably, the flaw detection head has a PT head for performing a penetrant flaw detection process on a welded portion and an observation head for performing observation after the process, and the PT head and the observation head are provided on the left and right sides of the arm.

[0016]

[0017]

In the present invention constructed as described above, a flaw detection head for performing a flaw detection test on the welded portion of the inner pipe is inserted into the gap between the inner pipe and the outer pipe through the access opening, and the inner pipe is positioned by the positioning means. Position outside the weld.

Further, a bell is used as a guide with an arm attached to the rotating ring by operation from the access opening.
The flaw detection head is moved to a predetermined position by moving the flaw detection head.

Further, by forming the arm and the rotary ring into an articulated shape, the arm and the rotary ring are inserted into a narrow gap between the inner pipe and the outer pipe from a small access opening, and assembled and arranged in the gap. Examples of articulated shapes include:
There are a case where the structure can be disassembled into a plurality of parts, and a case where a plurality of nodes are connected with a pin to form a structure that can be bent and stretched.

The flaw detection head and the arm can be connected to the inner tube and the outer tube by rotating the rotatable ring through the access opening using a rack cut on the outer periphery of the rotatable ring. The flaw detection head is rotated in the gap to position the flaw detection head at a predetermined position.

Further, the PT head and the observation head are provided on the left and right sides of the arm, so that the PT head performs the penetration testing of the welded portion, and the observation head performs the observation after the processing.

[0022]

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 2 is a sectional view of the entire reactor pressure vessel 1. The improved boiling water reactor (ABWR) employs an internal pump (RIP) as a recirculation pump, and the pressure vessel 1 has a RIP nozzle 1A having a through hole formed therein.
And the casing 2 of the RIP is the RIP nozzle 1A
In the through hole.

FIG. 3 is a sectional view showing details of the through hole of the RIP nozzle 1A. The casing 2 is welded to the reactor pressure vessel 1 via a weld 3 in the middle of the through hole. This welded portion forms a double pipe structure, the gap between the pipes is a narrow portion 4, and one (upper end) of the gap is closed. The other end (lower end) of the gap is also closed by the pad 6 for earthquake resistance, but an opening window 5 for accessing the gap is provided in a part of the reactor pressure vessel 1 corresponding to the outer tube. I have.

In this embodiment, a flaw detection test of the welded portion 3 is performed. FIG. 1 shows an overall configuration diagram of the flaw detection apparatus. In the figure, the flaw detection apparatus includes a rotating ring 7, a bending / extending arm 14 extending above the rotation ring, a PT head 15 attached to the uppermost stage of the bending / extending arm 14 and performing a penetrant detection process, and an observation head 18 performing observation after the process. A pressure feed header 17 for feeding a penetrant, a cleaning liquid, warm air, and a developer to the PT head 15 and the observation head 18, a control device 23 for controlling the rotation of the rotating ring, an observation device 21 for monitoring an image from the observation head, and a power supply 22. Having.

The rotating ring 7 has an inner diameter of RI shown in FIG.
The outer diameter is slightly larger than the outer diameter of the casing 2 of P, slightly smaller than the inner diameter of the reactor pressure vessel 1, and a rack 8 is cut on the outer periphery. The rotating ring 7 can be disassembled into several pieces in the circumferential direction, that is, it can be disassembled into one ring segment 7a for attaching an arm and several other ring segments 7b. These ring segments 7a and 7b are inserted one by one from the opening window 5 shown in FIG. 3, connected to each other, assembled into a ring shape, and arranged on the pad 6 in the narrow portion 4.

Further, a rack 8 cut on the outer circumference of a rotating ring assembled in a ring shape is engaged with a rotating motor 9 via a speed change gear 10, and the rotating motor 9 is attached to the reactor pressure vessel by mounting bolts 12. Attach it to the base 11 fixed to 1.

FIG. 4 shows the details of the bending and extending arm 14. As shown in FIG. The bending and extending arm 14 has an articulated structure, that is, the lowermost arm segment 14 attached to the rotating ring 7.
a, is composed of the uppermost arm segment 14b to which the PT head 15 and the observation head 18 are attached, and several arm segments 14c in the middle, and each arm segment is connected by a pin 37. . Each of these arm segments 14a to 14c
Has a length that can enter through the opening window 5, and
When the lowermost arm segment 14a is inserted into the lowermost arm segment 14a in order from the uppermost arm segment 14b and assembled, the tip of the arm segment 14b is configured to reach the upper end of the narrow portion 4 shown in FIG.

FIG. 5 is a sectional view of the lowermost arm segment 14a. A toothed roller 29 rotatably supported is incorporated in the lowermost arm segment 14a,
Further, the toothed roller 29 is provided with a toothed belt 13 set so that the steps mesh with each other. When the vertical movement motor 33 is driven by the control device 23 and the toothed roller 29 rotates via the bevel gear 31 and the flexible shaft 32, the toothed belt 13 moves up and down by a length corresponding to the number of rotations. I have.

FIG. 6 is a plan view of the uppermost arm segment 14b. A toothed roller 34 rotatably supported is incorporated in the uppermost arm segment 14b,
Like the toothed roller 29 of the lowermost arm segment 14a, the toothed belt 13 is applied. Toothed belt 13
Is mounted with a slider 35 to which the PT head 15 and the observation head 18 are fixed. When the toothed belt moves up and down, the slider 35 moves up and down using the arm segments 14a to 14c of the bending and extending arm 14 as guides.

FIG. 7 is a sectional view of the PT head 15. As shown in FIG. P
The T head is provided on the slider 35 shown in FIG. 6, and is configured to spray a penetrating liquid, a cleaning liquid, warm air, and a developing liquid.
It has a T nozzle 24. FIG. 8 is a front view of the PT nozzle 24.
Shown in The PT nozzle 24 has four nozzles of a permeating liquid nozzle 24a, a cleaning liquid nozzle 24b, a hot air nozzle 24c, and a developing liquid nozzle 24d, and has a structure arranged in a horizontal line in this order when viewed from the front.

In FIG. 7, the PT nozzle 24 is connected to the hose 1
6. The penetrating liquid, the cleaning liquid, the warm air and the developing liquid flowing through the nozzle 6 are respectively supplied to the penetrating liquid nozzle 24a and the cleaning liquid nozzle 24.
b, while blowing to the back surface 3A of the welded portion 3 in the narrow portion 4 from the hot air nozzle 24c and the developer nozzle 24d,
It rotates with the head 15.

FIG. 9 is a sectional view of the observation head 18. The observation head 18 is provided on a slider 35 shown in FIG. 6, and includes an illumination black light 28, a side-view mirror 25, and a small camera 26. The small camera 26 is provided with a filter 27 for preventing ultraviolet rays. Power is supplied to the illumination black light 28 by the power cable 19. After penetration test, the back surface 3 of the weld 3
The image reflected by the side-viewing mirror 25 of A is a small camera 26.
The image is transmitted through the camera cable 20 to the observation device 21 shown in FIG.

In the above configuration, when the control device 23 drives the rotation motor 9, the entire rotation ring 7 rotates in the narrow portion 4 via the transmission gear 10. Further, as the rotating ring 7 rotates, the bending / extending arm 14 having the PT head 15 and the observation head 18 at the upper end also becomes narrower.
Rotate inside.

Further, the PT head and the observation head 18 are driven by a vertical movement motor 33 by the control device 23 and the slider 35 fixed to the toothed belt 13 via the bevel gear 31.
Is moved up and down, so as to move up and down along the bending and extending arm 14.

Therefore, the PT head and the observation head 1
By rotating and moving up and down 8, it is positioned at an arbitrary position in the narrow portion 4.

After positioning the PT head and the observation head 18 on the back surface 3A of the welded portion 3 as described above, the PT head 15 performs the penetrating inspection process on the back surface 3A of the welded portion 3.
That is, first, the permeate sent through the hose 16 by the pressure feed header 17 is injected from the permeate nozzle 24a of the PT nozzle 24 provided in the PT head 15 to the back surface 3A of the welded portion. Wait for the permeate to penetrate into the interior of the weld 3,
Similarly, the cleaning liquid is sprayed from the cleaning liquid nozzle 24b to the welded portion 3A to wash the front surface of the welded portion back surface 3A. Similarly, hot air is sprayed from the hot air nozzle 24c to dry the welded portion back surface 3A. Then, the developer is sprayed from the developer nozzle 24d to the back surface 3A of the welded portion.

After completion of the penetrating inspection process, the observation head 18
To observe the penetrant detection processing section. That is, the black light 28 incorporated in the observation head 18 is turned on by the power cable 19 connected to the power supply 22, and the image signal of the back surface 3 </ b> A of the welded portion photographed by the small camera 26 of the observation head 18 is observed via the camera cable 20. It is received by the device 21 and observed.

FIG. 10 is a block diagram of the flaw detection system of this embodiment. The rotating ring 7 is rotated by the driving of the rotating motor 9, and the PT head 15 and the observation head 18 are rotated.
Is moved up and down along the bending and stretching arm 14 by driving the motor 33 for vertical movement. The rotation motor 9 and the vertical movement motor 33 are controlled by the control device 23.

On the other hand, a penetrating solution, a cleaning solution, warm air, and a developing solution are sent from the pressure feed header 17 to the PT head 15 to perform a penetrating flaw detection. Further, an image is received from the observation head 18 by the observation device 21 and observation is performed.

According to the present embodiment, the PT head 15 and the observation head 18 are inserted through the opening window 5 and
4 is used as a guide, and the rotating ring 7 is rotated using the rack 8, so that the PT head 15
In addition, the observation head 18 is positioned, and a penetration test can be performed on the back surface 3A of the inner pipe welded portion 3 from the narrow portion 4 of the gap between the casing 2 and the reactor pressure vessel 1.

The bending and extending arm 14 has a structure in which arm segments 14a to 14c are connected by pins 37, and the rotating ring 7 has a structure that can be disassembled into ring segments 7a and 7b. It can be inserted into the constriction 4 and assembled and arranged therein.

Further, since the vertical movement motor 33 and the rotation motor 9 are controlled by the controller 23, the PT head 15 and the observation head 18 can be accurately positioned at predetermined positions. Further, since the penetrating liquid, the cleaning liquid, the warm air, and the developing liquid are sent to the PT head 15 by the pressure feed header 17 and the image from the observation head 18 is monitored by the observation device 21, the flaw detection test can be efficiently performed by remote control.

In the above embodiment, the bending and extending arm 14 has a structure in which the arm segments 14a to 14c are connected by the pin 37, and the rotating ring 7 has a structure that can be disassembled into several pieces. It is also conceivable to adopt a structure that can be disassembled or a structure in which rings are connected by pins.

Although the description has been made using the PT head and the observation head as the flaw detection sensors, the same effect can be obtained by using a UT sensor that performs ultrasonic flaw detection, an ECT sensor that performs eddy current flaw detection, or the like as the flaw detection sensor. .

[0046]

According to the present invention, since the flaw detection head is inserted from the access opening and the flaw detection head is positioned outside the inner pipe weld by the positioning means, the inner pipe is welded from the gap between the inner pipe and the outer pipe. A flaw detection test can be performed on the part. Since the flaw detection head is moved by the belt using the arm as a guide, the flaw detection head can be positioned at a predetermined position and a flaw detection test can be performed. Further, since the arm and the rotating ring are articulated, they can be inserted into a narrow gap between the inner pipe and the outer pipe from a small access opening and assembled and arranged in the gap. Further, since the rotating ring is rotated by using the rack, the flaw detection head can be positioned at a predetermined position and a flaw detection test can be performed. In addition, since the PT head and the observation head are provided, it is possible to perform the penetrating detection processing of the welded portion.

[0047]

[0048]

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a flaw detector according to one embodiment of the present invention.

FIG. 2 is a sectional view of the entire reactor pressure vessel.

FIG. 3 is a cross-sectional view showing details of a through hole of a RIP nozzle.

FIG. 4 is a view showing details of a bending and extending arm.

FIG. 5 is a cross-sectional view of the lowermost arm segment.

FIG. 6 is a plan view of the uppermost arm segment.

FIG. 7 is a sectional view of a PT head.

FIG. 8 is a front view of a PT nozzle.

FIG. 9 is a sectional view of an observation head.

FIG. 10 is a block diagram of a flaw detection system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 reactor pressure vessel 1A RIP nozzle 2 casing 3 weld 3A weld back 4 narrow window 5 opening window 7 rotating ring 7a, b ring segment 8 rack 9 rotation motor 13 toothed belt 14 bending arm 14a-c arm segment Reference Signs List 15 PT head 17 Compression header 18 Observation head 21 Observation device 23 Control device 24 PT nozzle 24a Penetration liquid nozzle 24b Cleaning liquid nozzle 24c Hot air nozzle 24d Developer nozzle 26 Small camera 33 Vertical movement motor 37 Pin

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 21/88 G01B 11/30 G21C 17/003 GDC

Claims (6)

(57) [Claims] A gap between an inner pipe and an outer pipe is narrow, at least one of the gaps is closed, and an inner pipe welding portion of a double pipe structure having an access opening in the outer pipe. A flaw detection head for performing a flaw detection test on the inner pipe weld,
Have a positioning means for positioning the inspection head to the outside of the inner tube weld gap between the inner tube and the outer tube through the access opening, said positioning means, operated from the access opening
The belt that moves the flaw detection head to a predetermined position is
Attached and forms a guide for moving the flaw detection head
Arm that can be attached and detached
Rolling flaw detection apparatus characterized by chromatic and ring. 2. The flaw detector according to claim 1 , wherein the arm and the rotary ring are configured in a multi-joint shape. 3. The flaw detector according to claim 1 , wherein the arm and the rotary ring have a structure that can be assembled and disassembled at the opening. 4. The flaw detection device according to claim 1 , wherein the arm and the rotating ring have a plurality of nodes connected by pins and have a structure that can be bent and stretched. 5. The flaw detector according to claim 1 , wherein the rotation ring has a rack for rotating the flaw detection head and the arm by an operation from the access opening, which is cut at an outer periphery. Flaw detector. 6. The flaw detection apparatus according to claim 1 , wherein the flaw detection head has a PT head for performing a penetrant flaw detection process on a welded portion and an observation head for performing observation after the process. A flaw detection device provided on the left and right sides of the arm.