JPH04343095A - Inspection method and device for welding part of internal pump - Google Patents

Abstract

PURPOSE:To enable accessing easily, observing welding state from the backside wave bead and improving the intactness of the welding part. CONSTITUTION:An inspection device for internal pump welding part inspects the welding part 71 of an internal pump casing 13 fixed on a reactor pressure vessel nozzle 11. A radiation generation device 44 having an elevation driver 50 to elevate the radiation source is set on the nozzle 11 and an opening 17 for accessing is formed on the nozzle skirt 16 on the nozzle 11. In the sleeve shape gap 18 between the nozzle 11 and the casing 13, a film holder 20 charged with film 24 is inserted free of removal from the opening 17 and a holder elevation keeping device 21 connected with the holder 20 detachably is also inserted from the opening 17. The holder 20 is set on the position outside of corresponding welding part in the gap 18 with the device 21.

Description

[Detailed description of the invention]

0001 [Purpose of the invention]

0002

[Field of Industrial Application] The present invention relates to a method and apparatus for inspecting internal pump welds using a radiographic testing device, and in particular to a weld of an internal pump casing fixed to a reactor pressure vessel nozzle. The present invention relates to an inspection method and an inspection device for internal pump welds for confirming and inspecting the Uranami bead section.

0003

[Prior Art] In a boiling water reactor as a light water reactor, the coolant (reactor water) housed in the reactor pressure vessel is
It is returned to the reactor core as coolant by the reactor recirculation system. This reactor recirculation system consists of an external recirculation system in which the coolant inside the reactor pressure vessel is once taken out to the outside and then guided back into the reactor core, and the other is an external recirculation system in which the coolant is recirculated within the reactor pressure vessel and returned to the reactor core. There is an internal recirculation system to guide the process. Among these, the internal recirculation method is an advanced boiling water reactor (ABWR).
Applicable to , and equipped with an internal pump.

As shown in FIG. 7, a plurality of internal pumps 1, for example 8 internal pumps, are installed at the bottom (lower mirror) of the reactor pressure vessel 2.
From 10 to 10 units are installed at intervals in the circumferential direction. Specifically, a plurality of reactor pressure vessel nozzles (RPV nozzles) 3 are integrally formed at the bottom of the reactor pressure vessel 2, and the RP
The pump casing 4 of the internal pump 1 penetrates the nozzle hole 3a of the reactor pressure vessel 2 from below and is fixed to the V-nozzle 3 by welding, and is set in a suspended state.

[0005] The internal pump 1 is connected to the reactor pressure vessel 2.
It has a pump motor section 5 located outside and a pump impeller section 6 located inside the reactor pressure vessel 2, and the pump impeller section 6 is installed in a downcomer section 8 formed outside the core shroud 7. The internal pump 1 controls the core recirculation flow rate by changing the pump flow rate.

By the way, the pump casing 4 of the internal pump 1 is fixed to the RPV nozzle 3 by welding and suspended in a hanging state. Internal pump casing 4
If a welding defect occurs due to poor fusion in the welded part 9 of the It may develop into a leak.

Therefore, in order to improve the soundness of the pump casing weld 9 of the internal pump, it is necessary to accurately and reliably confirm weld defects and potential defect occurrence sites in and around the weld 9 of the pump casing 4. Needs to be inspected.

[0008]

[Problems to be Solved by the Invention] However, in conventional boiling water reactors, the internal pump casing 4
The sleeve-shaped gap formed between the RPV nozzle 3 and the RPV nozzle 3 is as small as several mm, for example, about 8 mm.
a is formed in the circumferential direction, and this circumferential pad 4a is RP
Since it was fitted into the lower part of the nozzle hole of the V-nozzle 3, the accessibility of the inspection device was poor, and it was not possible to access the position corresponding to the welding part of the internal pump casing.

In particular, once the internal pump casing 4 is fixed to the RPV nozzle 3 by welding, the pump casing weld 9 can be inspected from the nozzle hole side, and the welded part 9 of the welded part 9 can be checked. It was not possible to perform the test. For this reason, it has been difficult to confirm and inspect welding defects in the welded portion 9 of the internal pump casing 4 and welding defects due to dents in the underwave bead portion.

The present invention has been made in consideration of the above-mentioned circumstances, and improves the inspection property by making it possible to easily access the welded portion of the internal pump casing with a radiation testing device, and to check the welding condition of the welded portion. An object of the present invention is to provide an inspection method and an inspection device for internal pump welds, which can accurately and reliably confirm and inspect the internal pump welds and improve the soundness of the welds. [Structure of the invention]

[0011]

[Means for Solving the Problems] In order to solve the above-mentioned problems, a method for inspecting internal pump welds according to the present invention provides an internal pump welded part fixed to a reactor pressure vessel nozzle. In an internal pump weld inspection method for inspecting a weld of a null pump casing, a radiation generating device is installed in the reactor pressure vessel nozzle, and the radiation source of the radiation generating device is moved to correspond to the weld by a lifting drive device. At the same time, the film holder with the film attached is pushed circumferentially into the sleeve-shaped gap between the reactor pressure vessel nozzle and the internal pump casing through the access opening of the nozzle skirt, and the pushed film holder is inserted into the After connecting to the holder lifting/lowering holding device inserted through the access opening,
activating a fluid cylinder to raise the film holder within the sleeve-shaped gap to set the film in an outer position corresponding to the weld, and then applying radiation from a source section of the radiation generating device to the weld. In this method, the welded part is inspected by irradiating it under the photographing conditions, photographing it on film, and inspecting the welded part.

Further, in order to solve the above-mentioned problems, an internal pump welded part inspection device according to the present invention provides an internal pump casing fixed to a reactor pressure vessel nozzle. In an internal pump weld inspection device for inspecting a weld of An access opening is formed in the nozzle skirt of the reactor pressure vessel nozzle, and a film holder with a film attached thereto can be freely inserted into and removed from the access opening into the sleeve-shaped gap between the reactor pressure vessel nozzle and the internal pump casing. At the same time, a holder lifting/lowering holding device detachably connected to the film holder is inserted through the access opening, and the holder lifting/lowering holding device moves the film holder to an outer position corresponding to the welding part within the sleeve-shaped gap. It was retained.

[0013]

[Operation] The internal pump weld inspection method and inspection apparatus according to the present invention form an access opening in the nozzle skirt of a reactor pressure vessel nozzle, and from this access opening, the reactor pressure vessel nozzle (RPV The film holder with the film attached is pushed in the circumferential direction into the sleeve-shaped gap between the internal pump casing (nozzle) and the internal pump casing, and the fluid cylinder is operated while the pushed film holder is held by the holder elevating and lowering device that is also pushed in. The film holder is raised within the sleeve-shaped gap to accurately set the film mounted on the film holder in the outer position corresponding to the weld of the internal pump casing weld.

On the other hand, a radiation generating device is installed in the RPV nozzle, and the radiation source section of the radiation generating device is set at an inner position corresponding to the welding part by an elevating drive device.

After the radiation source section of the radiation generating device and the film attached to the film holder have been set, radiation is irradiated from the radiation source section to the welded part of the internal pump casing under required imaging conditions. Photograph the film and perform a confirmation inspection of the welded area.

At this time, the radiation generating device is installed in the RPV nozzle, and its radiation source can be easily set to the inside position corresponding to the welding part, while the film holder with the film attached is inserted through the access opening, and the holder is raised and lowered and held. It is held in the device and can be moved up and down inside the sleeve-shaped gap using a fluid cylinder to access the weld and set it to the outside position corresponding to the weld, improving inspection of the internal pump casing weld and inspecting the uranami bead. It is possible to perform a confirmation inspection for welding defects such as dents, and it is possible to accurately, reliably and accurately inspect welding defects and welding defects in the welded portion of the internal pump casing.

[0017]

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

FIG. 1 shows a partial cross section of the bottom (lower mirror) of a reactor pressure vessel 10 provided in a boiling water reactor as a light water reactor. A plurality of reactor pressure vessel nozzles (RPV nozzles) 11 are integrally molded around the bottom of the reactor pressure vessel 10, and an internal pump 1 is installed in the RPV nozzles 11.
The top of the second pump casing 13 is fixed by welding. The internal pump casing 13 is inserted from below into the reactor pressure vessel 10 through the nozzle hole 14, and its top is fixed to the RPV nozzle 11 in a suspended state by welding. A vibration-proof pad 15 is formed in the circumferential direction of the internal pump casing 13, and this pad 15 is connected to the nozzle hole 1.
4 to provide a vibration damping effect to the pump casing 13 of the internal pump 12.

The RPV nozzle 11 has a nozzle skirt 16 that projects below the reactor pressure vessel 10 and has an access opening 17 formed therein. Further, a sleeve-shaped gap 18 is formed between the RPV nozzle 11 and the pump casing 13 of the internal pump 12, and this sleeve-shaped gap 18 is about ten meters long.
m or more, for example, about 18 mm. The hole diameter d1 of the nozzle hole 14 of the RPV nozzle 11 is, for example, 348 mm.
φ, mouth outer diameter d2 of internal pump casing 13
is formed to have a diameter of 312 mm, for example.

From the access opening 17 of the nozzle skirt 16 of the RPV nozzle 11, the film holder 2 shown in FIG.
0 and the holder elevating and lowering holding device 21 are removably inserted. The film holder 20 is formed of a flexible band-shaped thin plate, and the insertion tip side and the insertion end side of the film holder 20 are removably connected with a one-touch detachable fitting (fastening fitting) 22, and are configured in a ring shape. Ru. Film holder 20
The holder element may have a two-part structure, and each of the two-part holder elements may be connected to each other by a one-touch detachable fitting 22 to form a ring shape.

A lead plate 23 for shielding radiation is stretched on the inside of the film holder 20, while a film mounting device 25 (such as a holding guide groove or a holding hook for holding the packed film 24 in a removable manner) is installed inside the film holder 20. 6(C)) is provided, and the packed film 24 is removably inserted into the inner peripheral side of the film holder 20 using this film mounting tool 25.

On the other hand, the holder lifting/lowering holding device 21 has two
It has a holding structure of stages (or one stage may be sufficient), and has flexible band-shaped holding plates 27 and 28. The band-shaped holding plates 27 and 28 may be a single plate or may have a structure that can be divided into several parts in the circumferential direction.
The insertion distal end sides of 7 and 28 are removably connected to the insertion distal end side with a one-touch detachable fitting 29, and are configured in a ring shape.

The holder lifting/lowering holding device 21 shown in FIG. 2 has a two-stage structure and includes an upper holding plate 27 and a lower holding plate 28. Air cylinders 30 as fluid cylinders are arranged at approximately equal intervals on the outer periphery of both holding plates 27 and 28.
31 are provided in pairs with each other. The piston rods 32 and 33 of the pair of air cylinders 30 and 31 extend in a direction toward each other, and their tips are removably connected by a concave-convex fit.

An air cylinder 35 as a fluid cylinder is also provided between the air cylinders 30 of the upper holding plate 27, and a one-touch detachable fitting 3 is attached to the tip of a piston rod 36 extending upward from the air cylinder 35.
7 is fixed, and this detachable fitting 37 is removably connected to a receiving fitting (bracket) 37a provided at a corresponding position on the film holder.

The air cylinders 30, 31, 35 fixed to the upper and lower holding plates 37, 28 of the holder lifting/lowering holding device 21 are connected to a compressed air cylinder as a pressure fluid source via a control box 40 via a supply/discharge pipe 39. 41, and the air cylinders 30, 31, and 35 are actuated by control from the control box 40, and can be raised and lowered. At this time, the strokes of the air cylinders 30, 31, and 35 are adjusted so that the packed film 24 held by the film holder 20 is set at an outer position corresponding to the welded portion of the internal pump casing 13.

On the other hand, an X-ray generator 44 as a radiation generator is installed in the RPV nozzle 11. A gamma ray generator may be provided in place of the X-ray generator 44. The X-ray generator 44 includes an X-ray generator 45, and the RPV nozzle 1
A pedestal 47 is fixed to the top of the frame 1 via a plurality of support legs 46 .

An elevating drive device 50 driven by a motor 48 is attached above the X-ray generator 45. This elevating drive device 50 is connected to a control box 52 via a control cable 51, and its operation is controlled by operating the control box 52. The screw shaft 55 attached to the nut 54 is driven to rotate by the motor 48 of the lifting drive device 50 via the reducer 49, and the guide shaft 55 is rotated by the rotation of the screw shaft 55.
, 56, the X-ray generator 45 is raised and lowered,
Its vertical position is measured by a potentiometer (not shown).

Further, below the X-ray generator 45, for example, there are three
A guide device 59 including guide rollers 58 is provided, and the guide device 59 smoothly guides the X-ray generator 45 up and down. A motor-driven cooling fan 60 is provided above the guide device 59.
The heat generated from the X-ray generator 45 is removed by driving the fan.

The X-ray generator 45 has a high-voltage transformer and an X-ray tube housed in a sleeve-shaped casing 61 made of corrosion-resistant aluminum, and is sealed with SF6 gas, etc., and is connected via a control cable 62 as shown in FIG. The X-ray generator 45 is connected to a controller 63, and the operation of the X-ray generator 45 can be controlled by the controller 63. In addition, the controller 63
is connected to a remote controller 65 via a remote control cable 64 as required, so that remote control operation can be performed using this remote controller 65. In addition, the code|symbol 66 is a power cable, and 67 is a warning light.

[0030] Also, the pedestal 47 of the X-ray generator 44 is equipped with an X-ray generator.
A borescope 70 is provided to adjust the radiation source position of the radiation generator 45, and the tip of the borescope 70 is set at the center of the weld bead of the internal pump casing weld 71. The source position adjustment of the X-ray generator 45 is as follows:
The elevator drive device 50 is operated while looking at the borescope 70, and the radiation source section (X-ray tube position) 72 is set to be located at the center of the position corresponding to the welding section.

Next, the procedure for inspecting the internal pump welds will be explained.

The welded portion 71 of the pump casing 13 of the internal pump 12 to the RPV nozzle 11 is inspected during welding (about three layers) and after welding all layers in order to improve the soundness of the welded portion. Prior to this inspection, the lifting drive device 50 equipped with the X-ray generator 44 and the borescope 70
, a film holder 20, a packed film 24, and a holder lifting/lowering holding device 21 are prepared.

After that, the internal pump casing 1
3. After setting a hole type permeameter (not shown) on the welded part 71 on the inner surface of 3, as shown in FIG.
The X-ray generating device 44 equipped with 0 is set and fixed at the upper end of the RPV nozzle 11.

After fixing the X-ray generator 44 to the RPV nozzle 11, in order to adjust the source position of the X-ray generator 45,
Set the borescope 70 at the center of the weld bead, drive the lifting drive device 50 while looking at the borescope 70, and set the source section 72 of the X-ray generator 45 to the center of the inner position corresponding to the welding part. do. After this setting, aging is performed to use the X-ray generator 45 of the X-ray generator 44 in a stable state.

On the other hand, at the same time or before or after the installation of the X-ray generator 44 and the adjustment of the source position, the access opening 17 formed in the nozzle skirt 16 of the RPV nozzle 11 is Insert the film holder 74 as necessary.

Subsequently, as shown in FIG. 6(C), the packed film 24 is attached to the strip-shaped film holder 20 over almost the entire surface thereof, and is integrated with the film holder 20. The film holder 20 with the packed film 24 mounted thereon is inserted into the RPV through the access opening 17 of the nozzle skirt 16.
Push the packed film 24 inside in the sleeve-shaped gap 18 between the nozzle 11 and the pump casing 13 in the circumferential direction, connect the insertion tip side and the insertion end side of the film holder 20 with the one-touch detachable fitting 22, and remove the ring. (FIG. 5(D)).

Next, the inserted film holder 20 is slightly lifted within the sleeve-shaped gap 18, and while maintaining this lifted state, the upper holding plate 27 of the holder lifting/lowering holding device 21 is moved as shown in FIG. 6(E). Push in circumferential direction. When pushing the upper holding plate 27 in the circumferential direction, the film holders 20 are sequentially connected using the one-touch detachable fitting 37 attached to the tip of the piston rod 36 of the air cylinder 35 as a fluid cylinder. At this time, the air cylinder 35 assumes a retracted position in which it does not operate. In this way, the upper holding plate 27 is sequentially connected to the film holder 20 and pushed in in the circumferential direction, and the insertion tip side and the insertion end side are connected to the one-touch detachable fitting 29.
connected to form a ring shape.

After the upper holding plate 27 is pushed in to form a ring shape, the lower holding plate 28 is pushed in in the circumferential direction while holding the holding plate 27 slightly lifted. When inserting this lower holding plate 28, the air cylinder 30
, 31 are connected to the upper holding plate 27 by sequentially engaging the piston rods 32 and 33 in a concave and convex manner. After the lower holding plate 28 is inserted into the sleeve-shaped gap 18 from the access opening 17, the insertion tip side and the insertion end side of the lower holding plate 28 are connected with a one-touch detachable fitting 29 to form a ring shape.

Next, the control box 40 is operated to control each of the air cylinders 30, 31, and 30 as fluid cylinders.
35 to lift the film holder 20 within the sleeve-shaped gap 18 by the holder lifting/lowering holding device 21;
As shown in FIGS. 2 and 6(F), the packed film 24 is set so as to be at the outer position corresponding to the welding part.

After the film holder 20 is set at a predetermined position, a high voltage is applied to the X-ray generator 45, and the ON- mode is set such that a high voltage is applied to the X-ray generator 45 and the X-ray is irradiated for one minute, and then the irradiation is stopped for one minute. Film photography is performed by simultaneously irradiating the entire circumference of the welded portion 71 with X-rays under photography conditions in which the OFF action is repeated several times.

After photographing a film by X-ray irradiation, the holder elevating and lowering holding device 21 and the film holder 20 are taken out from the access opening 17 by reversing the assembly procedure, and the X-ray generator 44 is removed from the RPV nozzle 11. After removal, the inspection of the pump casing welded portion 71 of one internal pump 12 is completed. This inspection is performed for each welded portion of each internal pump 12 to confirm the soundness of the welded portion. If a welding defect or poor welding is discovered, it will be repaired or replaced with a new one depending on the degree of the defect or defect.

[0042]

[Effects of the Invention] As described above, in the present invention,
Using the access opening provided in the nozzle skirt of the reactor pressure vessel nozzle, insert the film holder with the film attached or the holder lifting/lowering device into the sleeve-shaped gap between the reactor pressure vessel nozzle and the internal pump casing. The inserted film holder can be reliably and smoothly set to the outer position corresponding to the welded part of the pump casing using the holder lifting/lowering holding device, improving inspection of the welded part and making it easier to install it in the reactor pressure vessel nozzle. The radiation emitted from the radiation source of the radiation generator can be photographed on film through the welded area, allowing accurate and reliable inspection to confirm welding defects such as welding defects in the pump casing welded area and dents in the Uranami bead area. It is possible to improve the soundness of the welded part.

[Brief explanation of drawings]

FIG. 1 is a sectional view partially showing the bottom sectional structure of a reactor pressure vessel of a boiling water reactor.

FIG. 2 is a perspective view of a film mounting device showing essential parts of an inspection device for internal pump welds according to the present invention.

FIG. 3 is a sectional view showing part A in FIG. 2;

FIG. 4 is a diagram showing an X-ray generator installed in a reactor pressure vessel nozzle.

FIG. 5 is a configuration diagram showing a radiation testing device used in the internal pump welding part inspection device of the present invention.

FIGS. 6A to 6F are explanatory diagrams illustrating an inspection procedure using an inspection device for internal pump welds according to the present invention.

FIG. 7 is a sectional view showing how the internal pump is installed.

[Explanation of symbols]

10 Reactor pressure vessel 11 Reactor pressure vessel nozzle 12 Internal pump 13 Internal pump casing 14 Nozzle hole 15 Anti-vibration pad ■ 16 Nozzle skirt 17 Access opening 18 Sleeve-shaped gap 20 Film holder 21 Holder lifting/lowering holding device 22 One-touch type Detachable fitting 24 Packed film 27, 28 Holding plate 29 One-touch detachable fitting 30, 31, 35 Air cylinder (fluid cylinder) 4
0 Control box 44 X-ray generator (radiation generator) 45 X-ray generator 46 Support legs 50 Lifting drive device 59 Guide device 60 Cooling fan 63 Controller 65 Remote controller 70 Borescope

Claims (2)

[Claims] 1. In an internal pump weld inspection method for inspecting a weld of an internal pump casing fixed to a reactor pressure vessel nozzle, a radiation generating device is installed in the reactor pressure vessel nozzle, and the radiation The radiation source part of the generator is set to the inside position corresponding to the welding part by the lifting drive device, and the film holder with the film attached is inserted into the sleeve shape of the reactor pressure vessel nozzle and internal pump casing from the access opening of the nozzle skirt. After pushing the film holder circumferentially into the gap and connecting the pushed film holder to a holder lifting/lowering holding device inserted through the access opening, the fluid cylinder is actuated to raise the film holder within the sleeve-like gap. and setting the film at an outer position corresponding to the welded part, and then irradiating the welded part with radiation from the radiation source part of the radiation generating device under required imaging conditions and photographing the welded part, and inspecting the welded part. Features: Inspection method for internal pump welds. 2. In an internal pump weld inspection device for inspecting a weld of an internal pump casing fixed to a reactor pressure vessel nozzle, a radiation generating device is installed in the reactor pressure vessel nozzle, and the radiation The generator is equipped with an elevating drive device for elevating the radiation source, and an access opening is formed in the nozzle skirt of the reactor pressure vessel nozzle, and the reactor pressure vessel nozzle and internal pump casing are accessed from the access opening. A film holder with a film attached thereto is inserted in and out of the sleeve-shaped gap of the film holder, and a holder elevating and lowering device detachably connected to the film holder is inserted through the access opening, and the holder is moved up and down. An apparatus for inspecting an internal pump welded part, characterized in that a holding device holds the film holder at a position outside the sleeve-shaped gap corresponding to the welded part.