JP2007003400A - Control rod through hole member inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control rod through-hole member inspection apparatus which is applied to a control rod through-hole member in a reactor pressure vessel so that inspection can be performed with high accuracy.
SOLUTION: A guide pipe 10 is seated between an upper lattice plate 8 and a core support plate 9 in a reactor pressure vessel 1, and a manipulator 7 and a scanner 5 are suspended by a chain 12 of a chain block 11 therein. The ultrasonic probe 4 held by is moved by a manipulator 7 and a scanner 5 to perform ultrasonic flaw detection of the welded portion of the CRD stub tube 3 installed in the lower mirror 2.
[Selection] Figure 1

Description

  The present invention relates to a nondestructive inspection apparatus for a welded portion in a reactor pressure vessel, and in particular, a control for inspecting the soundness of a welded portion of a control rod through-hole member installed in the vessel. The present invention relates to a rod through-hole member inspection device.

  There have been various proposals for a flaw detection inspection apparatus that performs nondestructive inspection of the inside of a reactor pressure vessel. In the prior art example, a link is made from the top of the reactor pressure vessel. The ultrasonic probe held by the mechanism is inserted, the ultrasonic probe is moved by the link mechanism to scan the target portion, and ultrasonic flaw detection in the container is performed (for example, see Patent Document 1).

  In this prior art, a housing is temporarily installed in the housing of the control rod drive mechanism, which is abbreviated as CRD, and a multi-joint arm is attached here, and the link mechanism holding the ultrasonic probe from the multi-joint arm is operated. The jet pump diffuser and the baffle plate, which are furnace internal structures, are subjected to ultrasonic flaw detection (see, for example, Patent Document 1).

Further, as another example of the prior art, ultrasonic waves for stub welds, which are provided in a control rod drive mechanism and perform ultrasonic flaw detection from the inner surface of a control rod through-hole member called a stub tube. There is a flaw detection apparatus and a flaw detection method (for example, see Patent Document 2). In this prior art, a driving device is installed on the stub tube to be inspected, water is put into the stub tube, an ultrasonic probe attached to the driving device is scanned, and ultrasonic flaw detection is performed by a water immersion method. Like to do.
Japanese Examined Patent Publication No. 6-68485 Japanese Patent No. 3489036

  Among the above-mentioned conventional techniques, the conventional technique in which an ultrasonic flaw detector is inserted from the upper part of the reactor pressure vessel to perform measurement is used for scanning the multi-joint part and the link mechanism with a flat flaw detection surface and less interference. In places where there is sufficient space, flaw detection is possible.

  However, in the case of CRD stub tubes installed in the lower mirror at the bottom of the reactor, they are welded to the inclined surface of the lower mirror having a spherical shape, so that the flaw detection surface has a curved shape of curvature, and Because they are densely attached to the bottom of the reactor, the environment is narrow and there is not enough space.

  Moreover, a number of neutron measurement housings are attached between the CRD stub tubes, and a shroud support ring is also installed between the outer periphery of the CRD stub tube and the inner wall of the reactor pressure vessel. It is necessary to operate the mechanism, tilt the probe in accordance with the inclined surface of the lower mirror spherical surface, and scan the probe along the flaw detection surface having a curved inclination shape, but it is extremely difficult to cope with the conventional technique.

  In addition, when using a multi-joint portion and a link mechanism that can be operated only in the vertical rotation axis direction as in this prior art, if operated in a narrow place, the adjacent CRD stub tube, neutron measurement housing, shroud support ring, etc. The problem of causing the inspection apparatus to interfere occurs.

  Next, in the case of the prior art relating to the ultrasonic flaw detection apparatus for a stub weld and its flaw detection method, since there is a gap between the inner surface of the CRD housing and the weld of the CRD stub tube, it is difficult to propagate ultrasonic waves. It is difficult to apply ultrasonic flaw detection to an actual machine, and in the case of a welded portion of a CRD stub tube, the flaw detection portion is extremely narrow, so the drive device must be made compact. Is difficult to apply.

  For accurate ultrasonic flaw detection, it is necessary to improve the contact of the ultrasonic probe so that the ultrasonic waves are incident on the flaw detection surface as vertically as possible. In this case, the flaw detection surface has a curved shape. Therefore, it is difficult to improve the contact property of the ultrasonic probe with the conventional technology.

  An object of the present invention is to provide a control rod through-hole member inspection apparatus that is applied to a control rod through-hole member in a reactor pressure vessel so that inspection can be performed with high accuracy.

  The above-described object is to provide a control rod through-hole member inspection apparatus that performs non-destructive inspection of the welded portion of the control rod through-hole member in the reactor pressure vessel from the outer surface of the control rod through-hole member. This is achieved by providing a moving mechanism for bringing the probe in the vicinity of the probe and a moving mechanism for adjusting the posture of the probe to the surface of the inspection target part.

  At this time, a guide pipe disposed between the upper lattice plate and the core support plate installed in the reactor pressure vessel is provided, and a moving mechanism that brings the inspection probe in the vicinity of the site to be inspected, The above object can be achieved even if a moving mechanism for adjusting the posture to the surface of the inspection target part is suspended from the lower part of the core support plate via the guide pipe. Here, the inspection probe is used. May be replaced with either an ultrasonic probe or an overflow probe.

  According to the present invention, the moving mechanism for controlling and scanning the posture of an inspection probe such as an ultrasonic probe and the moving mechanism for positioning the moving mechanism around the CRD housing to be inspected are separately provided. The drive mechanism can be shared, and as a result, the drive mechanism for causing the inspection probe to follow the inspection target part can be made compact, and the inspection apparatus can be applied to a narrow portion where the CRD stub tube is installed. Can be applied.

  Further, since the posture of the inspection probe can be controlled, the inspection probe can be pressed perpendicularly to the flaw detection surface, and a more accurate flaw detection result can be obtained at the time of ultrasonic flaw detection. Even if there is a gap between the inner surface of the CRD housing and the welded portion of the CRD stub tube, since the flaw detection is performed from the outer surface of the CRD stub tube, the influence of the gap can be eliminated even in ultrasonic flaw detection.

  According to an embodiment of the present invention, a scanner for controlling and scanning the attitude of a probe for nondestructive inspection and a manipulator for positioning the scanner around the CRD housing are provided. In this case, only the drive mechanism necessary to make the ultrasonic probe follow the flaw detection surface can be collected. As a result, the drive system in the vicinity of the ultrasonic probe is made compact, and the narrow part where the CRD stub tube is installed is used. But it can be applied.

  In addition, since this scanner has a drive shaft necessary for pressing the ultrasonic probe perpendicularly to the flaw detection surface, accurate ultrasonic flaw detection can be obtained, and the inner surface of the CRD housing and the CRD stub tube can be obtained. Even if there is a gap in the weld, the incidence of ultrasonic waves is not affected by the gap because the flaw detection is performed from the outer surface of the CRD stub tube.

  Hereinafter, a control rod through-hole member inspection apparatus according to the present invention will be described in detail with reference to an embodiment shown in the drawings.

  FIG. 1 is an overall configuration diagram of an embodiment of the present invention. As is apparent from this figure, a bottom mirror 2 is provided at the bottom of a reactor pressure vessel 1 to which this embodiment is applied. A plurality of CRD stub tubes 3 are welded.

  Therefore, in this embodiment, the ultrasonic probe 4 is used to detect the welded portion of the CRD stub tube 3 by ultrasonic waves, and together with this, the scanner 5 and the manipulator 7, the guide pipe 10, the chain block 11, the chain 12, the work A carriage 13 and a rail 14 are provided.

  First, the scanner 5 constitutes a moving mechanism for aligning the posture of the inspection probe with the surface of the inspection target part. For this purpose, the scanner 5 holds the ultrasonic probe 4 and arbitrarily sets the angle of the ultrasonic probe 4. In other words, the probe 4 is made perpendicular to the flaw detection surface of the welded portion having an inclination and a curvature, and the ultrasonic probe 4 is pressed against the flaw detection surface, and the flaw detection surface is scanned by the ultrasonic probe 4. do.

  At this time, although not shown, an ultrasonic flaw detector is provided outside the reactor pressure vessel 1, and the cable is extended from there to the reactor pressure vessel 1 and connected to the ultrasonic probe 4. Thus, ultrasonic flaw detection by the ultrasonic probe 4 can be performed.

  In such a case, it is possible to apply an eddy current inspection technique. Therefore, when this eddy current inspection technique is applied to form an embodiment of the present invention, an eddy current probe is used instead of the ultrasonic probe 4, Instead of the ultrasonic flaw detector, an eddy current inspection device is provided.

  Next, the manipulator 7 constitutes a moving mechanism for bringing an inspection probe to the vicinity of the inspection target part. For this purpose, the manipulator 7 holds the scanner 5 and welds the scanner 5 from the vicinity of the CRD housing 6 to the CRD stub tube 3. Work to move to the department.

  At this time, the guide pipe 10 holds the manipulator 7 inside, and functions to prevent shaking in the left-right direction when the manipulator 7 is moved in the up-down direction. For this reason, the manipulator 7 held inside the guide pipe 10 is suspended from the chain block 11 by the chain 12, and can move up and down in the guide pipe 10, and the manipulator 7 is guided by the guide pipe 10. When positioned at the upper end of the guide 10, the guide pipe 10 is also configured to be suspended from the chain block 11 by the chain 12.

  Accordingly, in this state, the guide pipe 10 can be moved up and down together with the manipulator 7 by moving the manipulator 7 up and down by the chain block 11. It can be positioned in the reactor pressure vessel 1 by being inserted into the reactor pressure vessel 1 from above the plate 8 through the lattice of the upper lattice plate 8 and seated in the hole of the core support plate 9. It can be done.

  Here, as described above, the chain block 11 suspends the guide pipe 10 and the manipulator 7 with the chain 12 and moves the guide pipe 10 and the manipulator 7 in the vertical direction. The block 11 is held on the rail 14 of the work carriage 13 so as to be manually movable along the rail 14, and on the reactor pressure vessel 1, an arbitrary position in the reactor pressure vessel 1 is provided. Will be able to move up.

  Next, the operation of this embodiment will be described. In this embodiment of the control rod through-hole inspection apparatus, first, the scanner 5 provided with the ultrasonic probe 4 is attached to the tip of the manipulator 7, and then the guide pipe 10 is provided. The manipulator 7 with the scanner 5 suspended is inserted. In this state, the manipulator 7 is attached to the chain 12 of the chain block 11, the chain block 11 is operated, the manipulator 7 and the guide pipe 10 are lowered at a predetermined position in the reactor pressure vessel 1, and the upper lattice plate 8 A guide pipe 10 is seated on the core support plate 9 through the lattice.

  Next, after the manipulator 7 is lowered in the guide pipe 10 and positioned in the vicinity of the CRD housing 6, the manipulator 7 is operated to place the scanner 5 on the welded portion of the CRD stub tube 3 and attach it to the scanner 5. A certain ultrasonic probe 4 is scanned to carry out ultrasonic flaw detection.

  Therefore, according to this embodiment, since the guide pipe 10 is seated on the core support plate 9 through the space between the upper lattice plates 8, the scanner 5 holding the ultrasonic probe 4 and these are held during the flaw detection. The manipulator 7 can be easily brought to the lower side of the core support plate 9 and definitely at the required place.

  FIG. 2 shows details of the manipulator 7. As shown in FIG. 2, the manipulator 7 is constituted by an articulated arm mechanism having a five-axis movable mechanism from a rotating unit 71 to a rotating unit 75. In FIG. 2, (a) shows the initial state before the operation, and (b) shows the movement of each axis. At this time, although not shown in the drawing, each rotation mechanism is individually provided with a predetermined actuator, for example, an electric actuator.

  Therefore, as is clear from these drawings, according to the manipulator 7, the degree of freedom 5 can be given to the operation of the scanner 5. For this reason, although not shown, a control device for controlling the manipulator 7 is provided outside the reactor pressure vessel 1, and this is also connected to the manipulator 7 via a cable not shown. The electric actuator provided in the rotating part can be individually controlled.

  More specifically, the manipulator 7 is first operated to rotate in the direction of the arrow (A) by operating the rotating unit 71, and then operated by operating the rotating unit 72 to move to the arrow (B). A rotational movement in the direction is obtained. In the operation of the rotating unit 73, the rotational movement in the direction of the arrow (C) is obtained. In the operation of the rotating unit 74, the rotational movement in the direction of the arrow (D) is obtained. A rotational movement in the direction e) can be obtained, whereby the scanner 5 can be easily moved to the welded portion of the CRD stub tube 3.

  Next, the scanner 5 will be described. The scanner 5 includes a first rotation mechanism, a linear movement mechanism in the left-right direction, a second rotation mechanism, and a pressing mechanism for pressing the ultrasonic probe 4 against the flaw detection surface. Therefore, it is configured as shown in FIG. Here, (a) of FIG. 3 is a side view and (b) is a front view. The scanner 5 is connected with a cable from the manipulator 7 and is connected to the control device through the cable.

  First, the scanner 5 incorporates a drive unit 15 incorporating a motor 32 (described later) serving as a power source and a gear train (connection gear) for transmitting rotational power as the first rotation mechanism described above. The mechanism 16, the rotating shaft 17, and the connecting plate 18 are provided. By these, the connecting plate 18 is configured to obtain a rotational movement in the arrow direction.

  At this time, the power from the motor of the drive unit 15 is transmitted to the rotary shaft 17 via the gear train of the mechanism unit 16, and as a result, the connecting plate 18 attached to the rotary shaft 17 is driven in the direction of the arrow (H). become.

  Here, FIG. 4 shows details of the drive unit 15. When a current is supplied to the motor 32, the shaft 33 rotates. Therefore, the bevel gear 34 attached to the tip of the shaft 33 rotates, and the connecting gear 35 installed in the mechanism portion 16 rotates. At this time, a position detector 36 is provided on the shaft 33 of the motor 32 so that the movement of the connecting plate 18 can be controlled.

  Next, the connecting plate 18 includes a drive unit 19 having a built-in motor as a power source, a gear train (connecting gear) for transmitting rotational power, and a ball screw mechanism as the above-described linear movement mechanism in the left-right direction. The built-in mechanism portions 20 and 21 and the connecting plate 22 driven by the ball screw mechanism are provided, and the connecting plate 22 is configured to obtain linear movement in the direction of the arrow (g).

  At this time, the power from the drive unit 19 is transmitted to a ball screw mechanism that is also built in the mechanism unit 21 via a gear train (connecting gear) built in the mechanism unit 20, and as a result, the connecting plate 22 is It is driven in the left-right direction indicated by the arrow (g).

  Here, FIG. 5 shows details of the drive unit 19 and the mechanism units 20, 21. When a current is supplied to the motor 37, the shaft 38 rotates, and a connecting gear 39 provided on the shaft 38. , And the ball screw 40 connected to the connecting gear 39 is rotated. By the rotation of the ball screw 40, the ball nut engaged with the ball screw 40 is moved and the connecting plate 22 is driven in the left-right direction. At this time, the rotation amount of the motor 37 is detected by the position detector 41 so that the movement of the connecting plate 22 can be controlled.

  In addition, the connecting plate 22 includes a drive unit 23 having a built-in motor as a power source and a mechanism unit 24 having a built-in gear train (connecting gear) for transmitting rotational power as the second rotating mechanism. The rotary shafts 25 and 25a and the holder 26 are provided so that the holder 26 can be rotated in the direction of the arrow (H).

  At this time, the power from the drive unit 23 is transmitted to the rotary shaft 25 via a gear train built in the mechanism unit 24. As a result, the holder 26 attached to the rotary shafts 25 and 25a is moved to the arrow ( ) In the direction of rotation.

  The holder 26 is provided with slide guides 27, 27a, a holder 28, an air cylinder 29, and a rod 30 as the pressing mechanism described above, and linear movement in the arrow (re) direction is thereby performed by the holder 28. It is configured to be obtained.

  At this time, the slide guides 27 and 27 a are attached to the holder 28, where the air cylinder 29 is attached to the holder 28, and the rod 30 of the air cylinder 29 is attached to the holder 26. Accordingly, when air pressure is applied to the air cylinder 29, the holder 28 is linearly driven along the slide guides 27 and 27a in the direction of the arrow (L).

  Here, FIG. 6 shows details of the drive unit 23, the mechanism unit 24, and the holders 26, 28. When a current is supplied to the motor 42, the shaft 43 in the mechanism unit 24 rotates, and this The rotating shaft 25 is rotated via a connecting gear 44 provided on the shaft 43, and the holder 26 to which the rotating shaft 25 is attached rotates. The rotation amount of the motor 42 at this time is detected by a position detector 45 attached to the motor 42, and the movement of the holder 26 is controlled.

  Further, when air pressure is applied to the air cylinder 29 attached to the holder 28, the rod 30 attached to the holder 26 is projected, and the holder 28 is moved along the slide guides 27 and 27a connecting the holder 26 and the holder 28. Is driven in the vertical direction.

  Therefore, according to the scanner 5, in addition to the degree of freedom 5 given by the manipulator 7, that is, the degree of freedom 5 shown by the arrows (A) to (E) in FIG. 2, the arrows (F) to (F) in FIG. The degree of freedom 4 shown in (b) is given. Therefore, if the holder 31 of the ultrasonic probe 4 is attached to the holder 28, the ultrasonic probe 4 is also given a movement of 4 degrees of freedom by the scanner 5, and when viewed from the manipulator 7, the ultrasonic probe 4. Is finally given 9 degrees of freedom.

  Therefore, according to this embodiment, first, the manipulator 7 moves the scanner 5 to the welded portion of the CRD stub tube 3, and then the scan 5 causes the ultrasonic probe 4 to take an arbitrary posture before welding. Can be brought into contact with the part.

  Therefore, in this embodiment, the moving system of the ultrasonic probe 4 is divided into a moving system for setting the position and a moving system for controlling the posture, and the moving system for setting the position by the manipulator 7 is configured, and the scanner Thus, a moving system for controlling the posture is configured by 5, and this is the result.

  As a result, the scanner 5 can collect only the drive mechanism necessary for causing the ultrasonic probe 4 to follow the flaw detection surface. As a result, the drive system in the vicinity of the ultrasonic probe 4 can be made compact, and the CRD stub tube 3 can be made compact. Can be easily applied to narrow parts such as the lower mirror 2 in which a large number of are installed.

  As a result, even if the flaw detection surface has a curved slope at the bottom of the reactor or the like, according to this embodiment, the ultrasonic probe 4 can be pressed against the exploration surface with good contact.

  As a result, even when the CRD stub tube 3 and the like are in a dense and narrow environment and there is not enough space, according to this embodiment, the ultrasonic probe 4 is easily brought to the exploration surface, It can be pressed against the exploration surface with good contact.

  The operation according to the present embodiment at this time will be described with reference to FIG. Here, FIG. 7 (a) shows a state when the welded portion on the front side of the CRD housing 6 is an inspection target part, and FIG. 7 (b) shows the state shown in FIG. 7 (a). ) Is viewed from the A direction.

  In this case, first, the manipulator 7 is guided by the guide pipe 10 by the chain block 11 of FIG. 1 and lowered to the vicinity of the CRD housing 6. At this time, it goes without saying that the guide pipe 10 is first inserted from the upper lattice plate 8 and is seated on the core support plate 9.

  Next, the actuator of each axis of the manipulator 7 is controlled and driven in the rotational directions (A), (B), (C), (D), and (E). First, the scanner 5 is moved to the CRD stub tube 3. It is set to the position corresponding to the welded part. Next, the scanner 5 is controlled, and as shown in FIG. 7 (a), the arrow (he) direction and the arrow are set so that the ultrasonic probe 4 comes into vertical contact with the surface of the lower mirror 2 having an inclined shape. (G) Move the ultrasonic probe 4 in the direction.

  Next, as shown in FIG. 7B, the ultrasonic probe 4 is moved in the direction of the arrow (H) along the flaw detection surface curved in the axial direction of the CRD stub tube 3, and thereafter, the ultrasonic probe 4 Is moved in the direction of the arrow (re), the ultrasonic probe 4 is pressed against the flaw detection surface, and then the ultrasonic probe 4 is scanned in the left-right direction as indicated by the arrow (g) to obtain the CRD stub tube weld 46. Ultrasonic flaw detection is performed.

  Therefore, according to this embodiment, since the moving system of the ultrasonic probe 4 is divided into the scanner 5 and the manipulator 7, the scanner 5 has a drive shaft necessary for causing the ultrasonic probe 3 to follow the flaw detection surface. As a result, the drive system of the ultrasonic probe 4 is made compact, so that it can be applied to a narrow part such as the lower mirror 2 in which a large number of CRD stub tubes 3 are installed.

  In addition, since this scanner 5 is provided with a drive shaft necessary for pressing the ultrasonic probe 4 perpendicularly to the flaw detection surface, accurate ultrasonic flaw detection can be obtained and the outer surface of the CRD stub tube 3 can be obtained. Therefore, even if there is a gap between the inner surface of the CRD housing 6 and the welded portion of the CRD stub tube 3, there is no possibility that the incidence and propagation of ultrasonic waves will be affected, and therefore inspection can be performed with high accuracy. .

  In the above description, the ultrasonic probe 4 is provided in the scanner 5 and the ultrasonic flaw detection is performed. However, as described above, an eddy current probe is used as the inspection probe, and the eddy current flaw detection apparatus is used. If it connects to, the control-rod through-hole inspection apparatus by an eddy current flaw detection technique can be obtained.

It is explanatory drawing which shows one Embodiment of the control-rod through-hole member inspection apparatus by this invention. It is explanatory drawing which shows the detail of the manipulator in one Embodiment of this invention. It is explanatory drawing of the scanner in one Embodiment of this invention. It is explanatory drawing which shows the detail of the one drive part of the scanner in one Embodiment of this invention. It is explanatory drawing which shows the detail of the one part other drive part of the scanner in one Embodiment of this invention. It is explanatory drawing which shows the detail of another drive part of the scanner in one Embodiment of this invention. It is operation | movement explanatory drawing of one Embodiment of this invention.

Explanation of symbols

1: Reactor pressure vessel (RPV)
2: Lower mirror 3: CRD stub tube (control rod through hole member of control rod drive mechanism)
4: Ultrasonic probe 5: Scanner 6: CRD housing 7: Manipulator 71-75: Rotating part 8: Upper lattice plate 9: Core support plate 10: Guide pipe 11: Chain block 12: Chain 13: Work carriage 14: Rail 15 : Drive unit 16: Mechanism unit 17: Rotating shaft 18: Connection plate 19: Drive unit 20: Mechanism unit 21: Mechanism unit 22: Connection plate 23: Drive unit 24: Mechanism unit 25, 25a: Rotation shaft 26: Holder 27, 27a: Slide guide 28: Holder 29: Air cylinder 30: Rod 31: Holder 32: Motor 33: Shaft 34: Bevel gear 35: Connection gear 36: Position detector 37: Motor 38: Shaft 39: Connection gear 40: Ball screw 41 : Position detector 42: Motor 43: Shaft 44: Connecting gear 45: Position detector 46: CRD Stub tube weld

Claims (3)

In the control rod through-hole member inspection device that performs non-destructive inspection of the welded portion of the control rod through-hole member in the reactor pressure vessel from the outer surface of the control rod through-hole member,
A moving mechanism that brings the probe for inspection in the vicinity of the region to be inspected;
A control rod through-hole member inspection apparatus, characterized in that a movement mechanism for adjusting the posture of the inspection probe to the surface of the inspection target part is provided. In the control rod through-hole member inspection device according to claim 1,
Providing a guide pipe disposed between the upper lattice plate and the core support plate installed in the reactor pressure vessel;
A moving mechanism for bringing the inspection probe in the vicinity of the inspection target portion and a moving mechanism for aligning the posture of the probe with the surface of the inspection target portion are suspended below the core support plate via the guide pipe. A control rod through-hole member inspection device characterized by being configured to be lowered. In the control rod through-hole member inspection device according to claim 1,
The control rod through-hole member inspection apparatus, wherein the inspection probe is configured to be replaced with either an ultrasonic probe or an overflow probe.

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