JP7592542B2 - Riser brace inspection device and riser brace inspection method - Google Patents

Description

An embodiment of the present invention relates to a riser brace inspection device and a riser brace inspection method for inspecting the weld between a riser brace and a reactor pressure vessel.

In boiling water reactors, to evaluate the integrity of the core shroud welds and jet pumps inside the reactor pressure vessel, inspection equipment is inserted into a narrow space called the annulus, which is made up of the inner surface of the reactor pressure vessel, the outer surface of the core shroud body, and the baffle plate, and inspections are performed on the structures located in the annulus.

Conventionally, this type of inspection device includes a riser brace inspection device that is equipped with a cart attached to the top of the reactor pressure vessel and running in the circumferential direction of the reactor pressure vessel, a base that moves in the radial direction of the reactor pressure vessel, a mast that can be extended and retracted up and down, and a flaw detection probe attached to the lowest part of the mast (see, for example, Patent Document 1). This type of inspection device can remotely access the welded parts between the riser brace and the reactor pressure vessel by using the mast.

JP 2020-085709 A

However, the inspection device described in Patent Document 1 performs inspections by directly contacting the inspection probe with the inspection object. For this reason, it is difficult to directly contact a direct contact type inspection probe with inspection objects that have a curved shape rather than a flat shape, such as the fillet welds on the top and bottom surfaces of a riser brace or the fillet welds on the side surfaces. Furthermore, when the inspection object with a curved shape is small and located in a narrow area, it is not even possible to bring the inspection probe close to the inspection object in the first place. Therefore, with conventional inspection devices, it is extremely difficult to inspect the entire volume of the weld, including the fillet welds of the riser brace.

The objective is to obtain a riser brace inspection device and inspection method that can inspect welds by inspecting riser brace welds and heat-affected zones, including fillet welds, for shapes other than flat surfaces.

The present invention was made in consideration of the above circumstances, and aims to provide a riser brace inspection device and inspection method that can inspect the entire volume of the weld between the riser brace and the reactor pressure vessel, including the fillet weld.

In order to solve the above-mentioned problems, the riser brace inspection device according to the embodiment is a riser brace inspection device that nondestructively inspects the welded portion and heat-affected portion of the riser brace that fixes the riser pipe of the jet pump to the reactor pressure vessel, and includes a connection part, a clamping mechanism, a water-immersion type flaw detection probe, a translation mechanism, and a rotation mechanism. The connection part connects a support member for handling the riser brace inspection device remotely underwater within the reactor pressure vessel. The clamping mechanism is attached to the connection part and clamps the riser brace so as to independently fix and position the riser brace inspection device to the riser brace. The water-immersion type flaw detection probe ultrasonically inspects at least the curved surface area of the end of the welded portion of the riser brace. The translation mechanism is attached to the clamping mechanism and translates the water-immersion type flaw detection probe in each of three orthogonal axial directions. The rotation mechanism is attached to the translation mechanism and supports the water-immersion type flaw detection probe rotatably around each of two orthogonal axes so as to be able to transmit and receive ultrasonic waves perpendicular to at least the curved surface area of the welded portion.

The riser brace inspection device and inspection method according to an embodiment of the present invention can inspect the welds between the riser brace and the reactor pressure vessel, including the fillet welds.

FIG. 1 is an overall configuration diagram showing an example of a configuration of a riser brace inspection device according to an embodiment. FIG. 13 is a schematic side view for explaining an example of a method for installing the riser brace inspection device on the riser brace. FIG. 2 is a schematic perspective view showing an example of a riser brace inspection device installed on a riser brace. FIG. 4 is a plan view illustrating a curved region of a welded portion. FIG. 4 is a side view illustrating a curved region of a welded portion. FIG. 4 is a plan view showing an example of the posture of the flaw detection unit when inspecting a flat flaw detection surface. 13 is a plan view showing an example of the posture of the flaw detector when inspecting a curved area on the end side of a weld. FIG. 13 is a plan view showing an example of the orientation of the flaw detector when inspecting a curved area above an end of a weld. FIG. FIG. 13 is a perspective view showing one configuration example of a hanging and moving mechanism that suspends and supports the riser brace inspection device from above.

The embodiment of the riser brace inspection device and inspection method according to the present invention will be described with reference to the attached drawings.

Figure 1 is an overall configuration diagram showing an example of the configuration of a riser brace inspection device 10 according to one embodiment. Also, Figure 2 is a schematic side view for explaining an example of a method for installing the riser brace inspection device 10 to a riser brace 20.

As shown in FIG. 1, the riser brace inspection device 10 has a connection part 11, a clamping mechanism 12, a translation mechanism, a rotation mechanism, and a water-immersion type flaw detection probe 13.

The connection part 11 is provided on the upper part of the riser brace inspection device 10 as shown in FIG. 2, and connects support members for handling the riser brace inspection device 10 remotely underwater within the reactor pressure vessel 100.

The support member connected to the connection part 11 can be an operating pole 111 for manually lowering the riser brace inspection device 10 from above into remote water and operating the clamp mechanism 12 to install the riser brace inspection device 10 on the riser brace 20.

The clamping mechanism 12 is attached to the connection portion 11 and clamps the riser brace 20 so as to independently fix and position the riser brace inspection device 10 to the riser brace 20.

When fixing the riser brace inspection device 10 to the riser brace 20, as shown in Figure 2, an operating pole 111 is connected to the connection part 11 so that an operator can handle it remotely underwater from a work cart 101 located above the reactor pressure vessel 100.

The operating pole 111 may be connected to multiple poles until the riser brace inspection device 10 reaches the riser brace 20 to be inspected. In particular, in a narrow section called the annulus between the reactor pressure vessel 100 and the core shroud 120, the riser brace inspection device 10 may be carefully installed on the riser brace 20 by an operator directly handling the operating pole 111 so as not to collide with the structure. The riser brace inspection device 10 may further include a seating detection mechanism (not shown) that detects that the riser brace inspection device 10 has come into contact with the top surface of the riser brace 20 and seated thereon and notifies the operator of that fact. The seating detection mechanism may include, for example, a limit switch.

In this way, the riser brace inspection device 10 according to this embodiment can be handled underwater by a worker from a work cart 101 located above the reactor pressure vessel 100 by connecting the operating pole 111 to the connection part 11. Therefore, the riser brace inspection device 10 can be fixed to the riser brace 20 to be inspected without removing the inlet mixer, which is part of the jet pump 130. This makes it possible to reduce the number of workers and equipment required to remove the inlet mixer, and shorten the inspection work period.

The translation mechanism is attached to the clamp mechanism 12 and translates the flaw detection probe 13 in each of the three orthogonal axial directions. In the following description, the three orthogonal axes of the translation mechanism, the x-axis, y-axis, and z-axis, are defined as the vertical direction, the y-axis direction, the radial direction of the reactor pressure vessel 100, and the x-axis direction, which is perpendicular to the z-axis and y-axis.

As shown in FIG. 1, the translation mechanism includes an x-axis translation mechanism 31x that translates the riser brace inspection device 10 along the x-axis, a y-axis translation mechanism 31y that translates the riser brace inspection device 10 along the y-axis, and a z-axis translation mechanism 31z that translates the riser brace inspection device 10 along the z-axis. These translation mechanisms 31x-31z only need to be configured to be able to translate the riser brace inspection device 10 along each axis, and may be configured, for example, by a screw mechanism, pinion and rack, or linear motor type translation drive mechanism. For example, the x-axis translation mechanism 31x shown in FIG. 1 is configured by a rack-and-pinion mechanism.

The rotation mechanism is attached to the translation mechanism and supports the flaw detection probe 13 so that it can rotate freely around each of two orthogonal axes so that ultrasonic waves can be transmitted and received perpendicular to at least the curved area of the weld between the riser brace 20 and the reactor pressure vessel 100.

As shown in FIG. 1, the rotation mechanism includes a yaw rotation mechanism 41YW that rotates the riser brace inspection device 10 in a yaw direction when the x-axis direction is assumed to be the front-to-rear direction, and a roll rotation mechanism 41RL that rotates the riser brace inspection device 10 in a roll direction.

The yaw rotation mechanism 41YW has, for example, a base shaft side pulley, a probe side pulley, and a belt connecting them. When the base shaft side pulley rotates as driven by the yaw rotation drive motor 41yp, the probe side pulley rotates around the yaw axis 30, and the flaw detection unit 14 including the flaw detection probe 13 connected to the probe side pulley rotates integrally around the yaw axis 30.

The yaw rotation drive motor 41yp may be provided on the base shaft pulley instead of the probe pulley. By providing the yaw rotation drive motor 41yp on the base shaft pulley instead of the probe pulley, the flaw detection unit 14 can be easily inserted to perform flaw detection testing, even in a narrow space such as between two upper and lower leaves, without being hindered by the yaw rotation drive motor 41yp.

When the gear driven by the roll rotation drive motor 41rp rotates, the gear 42 meshing with the gear rotates, and the probe support member 43 attached to the gear 42 rotates around the roll shaft 40, so that the flaw detection probe 13 rotates integrally with the probe support member 43 around the roll shaft 40.

The immersion type flaw detection probe 13 has ultrasonic transducers arranged on a plane 15 parallel to the roll axis 40, and performs non-contact ultrasonic flaw detection at least in the curved area of the end (fillet weld) of the weld of the riser brace 20 at a distance from the inspection surface. The flaw detection probe 13 can be moved by a translation mechanism and a rotation mechanism to a position where it can transmit and receive ultrasonic waves perpendicular to at least the curved area of the weld between the riser brace 20 and the reactor pressure vessel 100.

The flaw detection probe 13 may be positioned at a position where it can transmit and receive ultrasonic waves perpendicular to at least the curved area of the weld between the riser brace 20 and the reactor pressure vessel 100 using a translation mechanism and a rotation mechanism. In other words, the normal to the transducer array surface of the flaw detection probe 13 does not need to be parallel to the normal to the flaw detection surface. The angle between these two normals should be within the range of angles at which the beam direction can be swung mechanically or by using a delay circuit.

The flaw detection probe 13 may be a one-dimensional array probe or a two-dimensional array probe in which multiple ultrasonic transducers are arranged in the scan direction (azimuth direction) and multiple elements are also arranged in the lens direction (elevation direction). Examples of this type of two-dimensional array probe that may be used include a 1.5D array probe, a 1.75D array probe, and a 2D array probe.

Figure 3 is a schematic perspective view showing an example of the riser brace inspection device 10 installed on the riser brace 20.

After the riser brace inspection device 10 is brought close to the riser brace 20 using the method shown in FIG. 2, the riser brace inspection device 10 is installed on the top surface of the riser brace 20. The riser brace inspection device 10 is then fixed to the riser brace 20 by the clamp mechanism 12.

As shown in FIG. 3, the riser brace 20 has a yoke portion 21 and leaf portions 22 welded to both ends of the yoke portion 21, and has a U-shape in plan view. The leaf portions 22 have an upper leaf 22U and a lower leaf 22L. FIG. 3 shows an example in which the riser brace inspection device 10 is fixed to the upper leaf 22U by the clamp mechanism 12.

After the riser brace inspection device 10 is fixed to the riser brace 20, the operating pole 111 may be removed using a remotely detachable attachment/detachment device (not shown) provided at the connection part 11. In this case, if multiple riser brace inspection devices 10 are prepared, it becomes possible to simultaneously inspect multiple riser braces 20 inside the reactor pressure vessel 100, including simultaneously inspecting the two upper and lower leaves of the riser brace 20, and the inspection period can be significantly shortened.

Figure 4 is a plan view illustrating the curved area of the welded portion 51. Figure 5 is a side view illustrating the curved area of the welded portion 51.

Specifically, the riser brace 20 is welded to the reactor pressure vessel 100 via the pad 100p. The riser brace inspection device 10 non-destructively and non-contactly inspects the soundness of the welded portion 51 and the heat-affected portion 52.

Here, the heat-affected zone 52 between the riser brace 20 and the reactor pressure vessel 100 is a region in the vicinity of the weld 51, for example 10 mm away from the weld toe, which is the boundary with the weld 51, toward the non-welded side.

The curved surface area of the weld 51 includes at least one of the upper corner 51t, the lower corner 51b, the left side corner 51L, and the right side corner 51L of each of the upper leaf 22U and the lower leaf 22L of the riser brace 20. Specifically, as shown in FIG. 4, the side of the end (fillet weld) of the weld 51 has a curved surface area 51L that protrudes to the left and right. Also, as shown in FIG. 5, the upper side of the end of the weld 51 has a curved surface area 51t, and the lower side of the end has a curved surface area 51b.

It is difficult to detect flaws in these curved regions 51L, 51t, and 51b with a direct contact probe. On the other hand, the flaw detection probe 13 according to this embodiment can easily and accurately perform ultrasonic flaw detection of the curved regions 51L, 51t, and 51b at a distance from the detection surface without contact by moving the probe 13 to a position where ultrasonic waves can be transmitted and received perpendicularly to each of the curved regions 51L, 51t, and 51b using a translation mechanism and a rotation mechanism.

In addition, by rotating the flaw detection probe 13 around the roll axis 40, the transmission direction of the ultrasonic waves can be directed upward. Therefore, the riser brace inspection device 10 can inspect the upper surface 22Ut of the upper leaf 22U and the upper surface 22Lt of the lower leaf 22L, and can also inspect the lower surface 22Ub of the upper leaf 22U and the lower surface 22Lb of the lower leaf 22L.

Figure 6 is a plan view showing an example of the posture of the flaw detection unit 14 when inspecting a flat surface to be inspected. Figure 7 is a plan view showing an example of the posture of the flaw detection unit 14 when inspecting the curved area 51L on the end side of the welded part 51. Also, Figure 8 is a plan view showing an example of the posture of the flaw detection unit 14 when inspecting the curved area 51t on the upper side of the end of the welded part 51.

Flat inspection surfaces such as the heat-affected zone 52 can be inspected without using a rotation mechanism (see Figure 6). In this case, the riser brace inspection device 10 is fixed to the riser brace 20 using the clamping mechanism 12, and then the translation mechanism is used to position the immersion inspection probe 13. The positioning of the immersion inspection probe 13 can be performed based on the received signal of the immersion inspection probe 13 while adjusting the amount of movement of each of the three orthogonal axes of the translation mechanism.

On the other hand, when inspecting the curved area 51L on the end side of the weld 51, the flaw detection probe 13 is rotated around the yaw axis 30 so that the slice direction of the transducer is perpendicular to the curved area 51L (see FIG. 7). Similarly, when inspecting the curved area 51t on the upper end side of the weld 51 or the lower end side 51b, the flaw detection probe 13 is rotated around the yaw axis 30 so that the slice direction of the transducer is perpendicular to the curved areas 51t and 51b (see FIG. 8). By using a translation mechanism and a rotation mechanism to scan the water immersion type flaw detection probe 13 attached to the riser brace inspection device 10 so as to face the weld 51 of the riser brace 20, the entire volume of the weld 51 can be inspected.

The flaw detection probe 13 according to this embodiment can be moved by a translation mechanism and a rotation mechanism to a position where ultrasonic waves can be transmitted and received perpendicularly to each of the curved regions 51L, 51t, and 51b. This allows the curved regions 51L, 51t, and 51b to be ultrasonically detected easily and accurately without contact at a distance from the flaw detection surface. Therefore, according to the riser brace inspection device 10 according to this embodiment, it is possible to easily and accurately inspect the entire volume of the weld 51 between the riser brace 20 and the reactor pressure vessel 100, including not only the heat-affected zone 52 but also the curved regions (fillet welds) 51L, 51t, and 51b.

Figure 9 is a perspective view showing an example of the configuration of a hanging and moving mechanism 60 that suspends and supports the riser brace inspection device 10 from above.

The riser brace inspection device 10 may be supported by a hanging movement mechanism 60 suspended from above so that it can be handled remotely within the reactor pressure vessel 100. The hanging movement mechanism 60 has a base 61, a radial movement mechanism 62 provided on the base 61, and a mast 63 suspended from the radial movement mechanism 62. The riser brace inspection device 10 may be equipped with the hanging movement mechanism 60.

The pedestal 61 is fixed above the riser brace 20. The pedestal 61 is installed, for example, at the upper end of the core shroud 120, almost directly above the riser brace 20 to be inspected. A positioning pin 64 may be vertically attached to the underside of the pedestal 61. The pedestal 61 is installed at the upper end of the core shroud 120 by fitting the positioning pin 64 into a head bolt bracket provided on the shroud upper ring at the upper end of the core shroud 120. As a result, the position (orientation) of the pedestal 61 relative to the circumferential direction of the reactor pressure vessel 100 and the core shroud 120 is determined.

The radial movement mechanism 62 moves the mast 63 installed on the radial movement mechanism 62 in the radial direction of the reactor pressure vessel 100 and the core shroud 120. The radial movement mechanism 62 has a radial rail 621 and an installation stand 622. The radial rail 621 is fixed to the upper surface of the base 61 and extends in the radial direction of the reactor pressure vessel 100 and the core shroud 120. The installation stand 622 is provided so as to be movable along the radial rail 621, and the mast installation portion 65 of the mast 63 is attached to the installation stand 622.

The mast 63 includes a mast body 66 and a mast installation section 65 that are connected to each other. The mast 63 is suspended from above the core shroud 120, avoiding the jet pump 130. The mast installation section 65 is provided on a radial movement mechanism 62 of a pedestal 61 that is installed at the upper end of the core shroud 120.

The lower end of the mast body 66 of the mast 63 is connected to the connection part 11.

The mast 63 has a built-in telescopic mechanism 67. The telescopic mechanism 67 telescopically extends and retracts the mast 63 in the height direction, allowing the riser brace inspection device 10 connected to the lower end of the mast 63 via the connection part 11 to be positioned in the vertical direction.

The suspension movement mechanism 60 may also have a rotation mechanism 68 that rotates either the mast 63 or the connection portion 11 in the circumferential direction of the mast 63. For example, when the rotation mechanism 68 is installed between the mast installation portion 65 and the mast body 66 of the mast 63, the rotation mechanism 68 can rotate the mast body 66 in the circumferential direction of the mast 63 relative to the mast installation portion 65. When the rotation mechanism 68 is installed between the lower end of the mast body 66 and the connection portion 11, the riser brace inspection device 10 can rotate in the circumferential direction of the mast 63 relative to the mast body 66.

Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are within the scope of the invention and its equivalents as set forth in the claims, as well as the scope and spirit of the invention.

10... riser brace inspection device, 11... connection part, 12... clamp mechanism, 13... water immersion type flaw detection probe, 14... flaw detection part, 20... riser brace, 22L... lower leaf, 22U... upper leaf, 30... yaw axis, 31x... x-axis translation mechanism, 31y... y-axis translation mechanism, 31z... z-axis translation mechanism, 40... roll axis, 41RL... roll rotation mechanism, 41YW... yaw rotation mechanism, 51... welded part, 51L, 51t, 51b... curved surface area (fillet part), 52... heat-affected zone, 60... hanging movement mechanism, 61... base, 62... radial movement mechanism, 63... mast, 67... extension mechanism, 100... reactor pressure vessel, 111... operation pole, 130... jet pump.

Claims (7)

A riser brace inspection device for non-destructively inspecting a welded portion and a heat-affected portion of a riser brace that fixes a riser pipe of a jet pump to a reactor pressure vessel, the riser brace comprising:
a connection portion for connecting a support member for remotely handling the riser brace inspection device underwater within the reactor pressure vessel;
a clamp mechanism attached to the connection portion and configured to clamp the riser brace so as to self-support and position the riser brace inspection device on the riser brace;
A water immersion inspection probe that ultrasonically inspects at least a curved surface area of an end of the weld of the riser brace;
a translation mechanism attached to the clamp mechanism and configured to translate the water immersion type flaw detection probe in each of three orthogonal axial directions;
a rotation mechanism attached to the translation mechanism and supporting the water immersion type flaw detection probe rotatably about each of two orthogonal axes so as to be able to transmit and receive ultrasonic waves at least perpendicular to the curved surface region of the weld;
a seating detection mechanism that detects that the riser brace inspection device is installed on the upper surface of the riser brace;
Riser brace inspection equipment equipped with The curved area of the weld is
at least one of an upper fillet, a lower fillet, a left side fillet, and a right side fillet of each of the upper and lower leaves of the riser brace;
2. The riser brace inspection apparatus of claim 1. The connection portion is
The riser brace inspection device is manually lowered from above into remote water, and an operating pole is connected to operate the clamp mechanism to install the riser brace inspection device on the riser brace.
3. The riser brace inspection device according to claim 1 or 2. The connection portion is
The operation pole is configured to be remotely detachable,
4. The riser brace inspection apparatus of claim 3. a suspension movement mechanism including a base fixed above the riser brace, a radial movement mechanism provided on the base, and a mast suspended from the radial movement mechanism, for remotely handling the riser brace inspection device within the reactor pressure vessel;
Further equipped with
The lower end of the mast is detachably connected to the connection portion.
5. The riser brace inspection device according to claim 1. The mast has a telescopic mechanism that can be extended and retracted in a vertical direction,
The water immersion type flaw detection probe is positioned in the vertical direction by extension and contraction of the mast.
6. The riser brace inspection apparatus of claim 5. A riser brace inspection method using a riser brace inspection device for non-destructively inspecting a welded portion and a heat-affected portion of a riser brace that fixes a riser pipe of a jet pump to a reactor pressure vessel, the method comprising:
clamping the riser brace to self-supportingly position the riser brace inspection device on the riser brace;
A step of translating the water immersion inspection probe of the riser brace inspection device in each of three orthogonal axial directions and rotating it around each of two orthogonal axes to position the water immersion inspection probe at a position where ultrasonic waves can be transmitted and received perpendicular to at least the curved surface area of the end of the weld;
ultrasonically inspecting the curved surface area using the water immersion inspection probe;
detecting that the riser brace inspection device is installed on a top surface of the riser brace;
A riser brace inspection method comprising:

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