JPH08304360A - Flaw detecting device of nuclear reactor pressure vessel nozzle part - Google Patents

Abstract

PURPOSE: To provide a flaw detecting deice for reactor pressure vessel nozzle in which a flaw detection can be smoothly performed in a radius part. CONSTITUTION: This device has a probe 6 loaded on a truck 1 traveling along the peripheral part of the nozzle 41 of a pressure vessel to perform a flaw detection in a nozzle inner surface curved part 49 by this probe 6. The truck 1 has a rotating part 5 having a rotating shaft 4 right-angled to the shaft of the nozzle 41, the probe 6 is mounted on the rotating part 5, and the outer surface curved part of the probe 6 is moved in close contact with the nozzle outer surface curved part 44.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting an inner surface of a nozzle of a reactor pressure vessel from an outer surface thereof,
The present invention relates to a flaw detection device for a reactor pressure vessel nozzle portion that can smoothly detect an inner curved portion (radius portion).

[0002]

2. Description of the Related Art Various pipes are connected to a reactor pressure vessel. The piping is connected to the outer circumference of the reactor pressure vessel through a nozzle, and is regularly checked to check the integrity of the joint between the reactor pressure vessel and the nozzle, the joint between the nozzle and the pipe, the inner surface of the nozzle, etc. Ultrasonic flaw detection is performed.

FIG. 4 shows the vicinity of the nozzle,
The nozzle 41 is a mating surface portion 4 with the reactor pressure vessel 42.
3, a nozzle outer curved portion (radius portion) 44 having a curved surface whose section including the axis of the nozzle is an arc, a large-diameter cylindrical portion 4
5, the small-diameter cylindrical portion 4 to which the conical surface portion 46 and the pipe 48 are connected
It consists of 7. In this way, the nozzle 41 has a large diameter in the vicinity of the reactor pressure vessel 42, and
The diameter becomes smaller as it goes away from 2. A nozzle inner surface curved portion (radius portion) 49 is formed on the inner surface of the nozzle. Near the weld between the reactor pressure vessel 42 and the nozzle 41 4
3a, the vicinity 47a of the welded portion between the nozzle 41 and the pipe 48, and the radius portion 49 on the inner surface of the nozzle are obligatory as the target range of ultrasonic flaw detection. The flaw detection of the radius portion 49 on the inner surface of the nozzle is performed from the radius portion 44 on the outer surface.

FIG. 5 shows an example of a conventional flaw detector. The flaw detection device includes a carriage 51 that is attracted to the outer circumference of the nozzle 41 and travels in the circumferential direction of the nozzle 41, and an axial movement unit 52 that is attached to the carriage 51 and moves on the carriage in the axial direction of the nozzle 41.
And the arm support part 5 attached to the axial movement part 52.
3, an arm base 54 which is guided by the arm support 53 and moves in the radial direction of the nozzle 41, an arm rotation shaft 55 attached to the arm base 54, and an arm rotation shaft 55.
It is composed of an arm 56 that is rotatable about the axis toward the reactor pressure vessel 42, and an ultrasonic probe 57 attached to the tip of the arm.

At the time of inspection, the axial direction moving portion 52 is attached to the nozzle 4
1, the arm base 54 is moved in the radial direction of the nozzle 41 to move the ultrasonic probe 57 to the mating surface portion 4.
Position to 3. When the ultrasonic probe 57 is pressed by the rotational movement of the arm 56 and the carriage 51 is caused to travel along the large diameter cylindrical portion 45 of the nozzle 41, the predetermined position of the mating surface portion 43 is inspected along the circumferential direction of the nozzle 41. it can. The inspection of the mating surface portion 43 is completed by moving the arm base portion 54 at a predetermined pitch for each revolution of the carriage 51.
When the ultrasonic probe 57 comes to the radius part 44,
The ultrasonic probe 57 is positioned by moving the axial movement portion 52 and the arm base portion 54 together. In inspecting the radius portion 49 by entering from the radius portion 44, the axial movement portion 52 and the arm base portion 54 are combined and moved so that the ultrasonic probe 57 moves in an arc, and the carriage 5 is moved.
The inspection is performed at a predetermined angle pitch for every one revolution.

[0006]

In the conventional flaw detector, the mating surface portion 43 and the radius portion 49 can be inspected. However, when inspecting the radius portion 49,
The circular movement is realized by combining linear movements in two directions, that is, the movement of the nozzle 41 in the axial direction and the movement of the nozzle 41 in the radial direction. However, it is difficult to obtain an accurate circular motion and a predetermined angular pitch with a combination of linear motions in two directions, and it is difficult to cause the ultrasonic probe 57 to smoothly detect the radius portion 44.

Further, since the ultrasonic probe 57 is pressed by the rotational movement of the arm 56, the pressing direction does not coincide with the radial direction of the circular arc of the radius portion 44, and the ultrasonic probe 57 is not always required. Do not face the radius part 44 directly.

Further, the axial movement portion 52 and the arm base portion 54
Requires a stroke corresponding to the radius of the circular arc of the radius portion 44, so that the mechanism becomes large and the driving power is wasteful.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a flaw detector for a reactor pressure vessel nozzle which can smoothly detect the radius portion.

[0010]

In order to achieve the above object, the present invention mounts a probe on a carriage that runs along the outer peripheral portion of a nozzle of a pressure vessel, and uses this probe to form a curved portion on the inner surface of the nozzle. In an apparatus for flaw detection, the carriage is provided with a rotary portion having a rotary shaft in a direction perpendicular to the axis of the nozzle, the probe is attached to the rotary portion, and the outer curved portion of the probe is rotated by the rotation of the rotary portion. Is configured to move in close contact with the curved portion of the outer surface of the nozzle.

The probe may be movable in the radial direction of the rotating portion.

The carriage is provided with an axial moving portion that moves in the axial direction of the nozzle, a radial moving portion that moves in the radial direction of the nozzle is provided in the axial moving portion, and the rotating portion is provided in the radial moving portion. It may be mounted so that its rotation axis can be moved to the center of bending of the curved portion of the nozzle outer surface.

At least two laser type distance detectors for detecting the distance from the nozzle may be mounted on the carriage.

[0014]

With the above structure, since the rotating part has the rotating shaft in the direction perpendicular to the axis of the nozzle and the probe is supported by the rotating part, the rotating part causes the probe to rotate as described above. It rotates around an axis and makes an accurate circular motion. On the other hand, the curved portion of the nozzle outer surface forms an arc with a surface including the axis of the nozzle. Therefore, when the rotating portion rotates, the outer curved portion of the probe comes into close contact with the outer curved portion of the nozzle, and the inner curved portion of the nozzle can be smoothly detected.

Since the probe is movable in the radial direction of the rotating portion, the outer curved portion of the probe can be correctly pressed against the outer curved portion of the nozzle.

The bending diameter of the outer curved portion of the nozzle may differ depending on the size of the nozzle. Therefore, the axial moving unit is moved in the axial direction of the nozzle, and the radial moving unit is moved in the radial direction of the nozzle, so that the rotating unit is moved in the axial direction and the radial direction of the nozzle. With this configuration, the rotating shaft of the rotating portion is moved so as to come to the center of bending of the nozzle outer surface bending portion, and when the rotating portion is rotated there, the outer surface bending portion of the probe is moved in close contact with the nozzle outer surface bending portion. be able to. As a result, the flaw detector for the nozzle part of the reactor pressure vessel of the present invention can be used regardless of the size of the nozzle.

By mounting the laser type distance detector on the carriage, the distance from the nozzle can be detected when the carriage or each moving part is moved. Further, by using two laser type distance detectors, detection error can be prevented.

[0018]

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

FIG. 2 shows a side view of the flaw detector of the reactor pressure vessel nozzle portion according to the present invention, FIG. 3 is a plan view thereof, and FIG. 1 is a view attached to the nozzle. The flaw detection device of the nozzle part of the reactor pressure vessel is composed of a carriage 1 adsorbed on the outer circumference of the nozzle 41 and traveling in the circumferential direction of the nozzle 41, and an axis attached to the carriage 1 and moving on the carriage 1 in the axial direction of the nozzle 41. The directional moving unit 2, the radial moving unit 3 attached to the axial moving unit 2 and moving on the axial moving unit 2 in the radial direction of the nozzle 41, and the shaft of the nozzle 41 mounted on the radial moving unit 3. A rotating part 5 having a rotating shaft 4 in a direction perpendicular to the rotating part 5; and a superstructure having a rotating part 5 movably supported in the radial direction of the rotating part 5 and having an outer curved part directed outward in the radial direction of the rotating part 5. The sound wave probe 6 is included. The outer curved portion of the ultrasonic probe 6 is convexly curved to form an ultrasonic sensor surface.

Next, the details of each part will be described.

The trolley 1 is provided with a drive wheel 21 and an auxiliary wheel 22 that are in contact with the large diameter cylindrical portion 45 of the nozzle, and a guide wheel 23 that is in contact with the conical surface portion 46 of the nozzle. The drive wheel 21, the auxiliary wheel 22 and the guide wheel 23 are all composed of magnets,
The trolley 1 can rotate around the outer periphery of the nozzle 41 while adsorbing these wheels to the nozzle 41, and during traveling, the trolley 1 is balanced by the attraction force of each wheel so that the trolley 1 is conical with the large-diameter cylindrical portion 45. The distance from the boundary with the surface portion 46 is automatically adjusted to a predetermined distance. Drive wheel 2
1, the auxiliary wheel 22 and the guide wheel 23 are provided in two sets, and each set is arranged so as to sandwich the carriage 1 in the circumferential direction of the nozzle 41. The posture parallel to the tangent line of the nozzle 41 on the center line of 41 can be maintained. The main frame 24 of the carriage 1 extends in the axial direction of the nozzle 41, and a linear rail 25 parallel to the axis of the nozzle 41 is provided on the main frame 24.

The axial moving portion 2 is composed of a moving element 26 which is guided by the linear rail 25 to reciprocate, and a substantially box-shaped main housing 27 mounted on the moving element 26. A pipe side of the main housing 27 serves as a connector portion 28 for exchanging power, drive control, inspection information and the like with the outside, and a moving shaft 29 extending in the radial direction of the nozzle 41 is provided on the reactor pressure vessel side. It is provided.

The radial direction moving portion 3 is composed of a moving element 30 which is guided by the moving axis 29 and reciprocates, and a sub-housing 31 mounted on the moving element 30. This sub housing 3
1, laser type distance detectors 36 for detecting the distance from the nozzle are attached on both sides of the center line. The sub-housing 31 supports the rotary shaft 4 orthogonal to the axis of the nozzle 41.

The rotating part 5 includes a rotating disc 32 attached to one end of the rotating shaft 4, and a linear slider fixing piece 33 diametrically attached to the outer surface of the rotating disc 32.
A movable piece 34 of a linear slider that linearly moves back and forth along the fixed piece 33, and an L attached to the movable piece 34.
And the arm part 35. The L-shaped arm portion 35 has a base end portion 35a.
Extends in the radial direction of the rotating portion 5, and the tip end portion 35b bent on the reactor pressure vessel side is orthogonal to the axis of the nozzle 41.

Two ultrasonic probes 6 are attached to the distal end portion 35b of the L-shaped arm portion 35, and the outer curved portion 6a of each ultrasonic probe 6 is radially outward of the rotating portion 5. Is directed to. The two ultrasonic probes 6 are arranged so as to be parallel to the tangent line of the nozzle 41 with the center line of the nozzle 41 on which the carriage 1 is located sandwiched.

Next, the operation of the embodiment will be described.

The trolley 1 can travel along the large diameter cylindrical portion 45 of the nozzle by the rotation of the drive wheel 21. During traveling, the bogie 1 is automatically adjusted to a predetermined distance from the boundary line between the large-diameter cylindrical portion 45 and the conical surface portion 46 due to the balance of the attraction forces of the wheels. In addition, the main frame 24 of the carriage 1
Maintains a posture parallel to the tangent line of the nozzle 41 on the center line of the nozzle 41. Therefore, the ultrasonic probe 6 mounted on the main frame 24 goes around a fixed position around the axis of the nozzle 41. The inspection is performed by moving the ultrasonic probe 6 by a predetermined angle pitch each time the carriage 1 goes around.

The positioning operation of the ultrasonic probe 6 will be described.

The radius portion 4 is made different depending on the size of the nozzle 41.
Since the diameters of the circular arcs 4 are different, the axial movement unit 2 is moved in the axial direction of the nozzle 41, and the radial movement unit 3 is moved in the radial direction of the nozzle 41. Specifically, the axial moving unit 2 is guided by the linear rail 25 to move in the axial direction of the nozzle 41, and the radial moving unit 3 is guided by the moving shaft 29 to move in the radial direction of the nozzle 41. In this way, the rotating unit 5
Is moved in the axial direction and the radial direction of the nozzle 41, and the rotary shaft 4
Is positioned at the center of the arc of the radius portion 44. At that time, since the laser type distance detector 36 detects the distance from the nozzle, the positioning becomes accurate.

The strokes of the axial moving portion 2 and the radial moving portion 3 may be of a size capable of compensating for the difference in the diameter of the circular arc of the radius portion 44 depending on the size of the nozzle 41. No stroke is needed to compensate for the diameter. Therefore, the nozzle radius portion flaw detector of the present invention may be small in size and have a small driving force.

In this way, the rotary shaft 4 is connected to the radius portion 4
When located at the center of the arc of 4, the movable piece 34 moves relative to the fixed piece 33 of the linear slider, and the L-shaped arm portion 35 moves toward the radius portion 44. The ultrasonic probe 6 is pressed against the radius portion 44 with an appropriate pressure. As described above, since the ultrasonic probe 6 is movable in the radial direction of the rotating portion 5, the ultrasonic probe 6 can be pressed against the radius portion 44 with appropriate pressure.

The predetermined pitch movement of the ultrasonic probe 6 is
It is performed by rotating the rotating disk 32 of the rotating unit 5 around the rotating shaft 4 at a predetermined angle pitch. The rotating part 5 has the rotating shaft 4 in a direction perpendicular to the axis of the nozzle 41, and the ultrasonic probe 6 is supported by the rotating part 5, so that the rotating part 5 rotates to cause the ultrasonic probe to rotate. The reference numeral 6 rotates around the rotation axis 4 to perform an accurate circular arc movement. In addition, as shown in the figure,
It is sufficient that the range of the arc movement is about 90 °. Particularly, the range that needs to be inspected is a limited range including the radius portion 49 on the inner surface of the nozzle.

The rotary shaft 4 is placed at the center of the circular arc of the radius portion 44.
Is located, the ultrasonic probe 6 is located at the radius portion 4
It will rotate and move along 4. Since the ultrasonic probe 6 has the outer curved portion 6a directed outward in the radial direction of the rotating portion 5, the ultrasonic probe 6 always moves to face the radius portion 44. Therefore, the radius portion 44 can be smoothly detected. In this way, it becomes possible to accurately detect the defect 7 occurring in the radius portion 49 on the inner surface of the nozzle.

[0034]

The present invention exhibits the following excellent effects.

(1) Since the probe makes an accurate arc movement, the inspection of the radius part becomes accurate.

(2) Since the circular arc motion can be performed only by the rotation of the rotating part, the power can be reduced.

(3) In the structure in which the probe is movable in the radial direction of the rotating part, the ultrasonic probe can be correctly pressed against the radius part from the bending radial direction.
Radius inspection is accurate.

(4) In the structure in which the ultrasonic probe is movable in the radial direction of the rotating portion and the rotating shaft can move to the center of the arc of the radius portion, the radius portion can be accurately moved regardless of the size of the nozzle. Inspection is possible.

[Brief description of drawings]

FIG. 1 is a diagram in which a flaw detection device for a reactor pressure vessel nozzle portion according to an embodiment of the present invention is attached to a nozzle.

FIG. 2 is a side view of a flaw detection device for a reactor pressure vessel nozzle portion according to the present invention.

FIG. 3 is a plan view of a flaw detector for a nozzle part of a reactor pressure vessel according to the present invention.

FIG. 4 is a sectional view in the vicinity of a nozzle of a reactor pressure vessel.

FIG. 5 is a side view of a conventional flaw detection device.

[Explanation of symbols]

 1 Bogie 2 Axial moving part 3 Radial moving part 4 Rotating shaft 5 Rotating part 6 Probe (ultrasonic probe) 36 Laser distance detector 41 Nozzle 42 Reactor pressure vessel 44 Nozzle outer curved part (radius part) ) 49 Nozzle inner curved portion (radius portion)

Claims (4)

[Claims] 1. A device in which a probe is mounted on a carriage that travels along the outer peripheral portion of a nozzle of a pressure vessel, and a flaw is detected on the curved portion of the inner surface of the nozzle by the probe, in the direction perpendicular to the axis of the nozzle. A rotary part having a rotary shaft is provided and the probe is attached to the rotary part, and the rotation of the rotary part causes the outer curved part of the probe to move in close contact with the nozzle outer curved part. A flaw detector for a reactor pressure vessel nozzle. 2. The flaw detection device for a reactor pressure vessel nozzle portion according to claim 1, wherein the probe is configured to be movable in a radial direction of the rotating portion. 3. The trolley is provided with an axial moving portion that moves in the axial direction of the nozzle, and the axial moving portion is provided with a radial moving portion that moves in the radial direction of the nozzle, and the radial moving portion is provided with the rotating portion. 3. The flaw detection device for a reactor pressure vessel nozzle portion according to claim 2, wherein the portion is mounted so that its rotation axis can be moved to the center of bending of the curved portion of the outer surface of the nozzle. 4. The flaw detector for a reactor pressure vessel nozzle according to claim 1, wherein at least two laser type distance detectors for detecting a distance from the nozzle are mounted on the carriage.