JP2002277582A - Surface reforming device of jet pump and surface reforming method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of a stress-corrosion cracking by allowing the reduction or compression of a tensile residual stress on the inner surface of a jet pump by laser irradiation from the inner surface to the weld part of the jet pump and the improvement of the texture of the inner surface. SOLUTION: This surface reforming device of jet pump for reforming the inner surface of the riser 6, elbow 5, thermal sleeve 4, safe end weld part 4a and vicinity thereof a jet pump 3 in a reactor pressure vessel 1 for boiling water reactor comprises a polishing device 9, laser irradiation device 35 and inspection device 27 successively introducible from the outside of the reactor in the opened state of a recirculation inlet nozzle 2 having the thermal sleeve 4 of the jet pump 3 inserted thereto and drivable on the inner surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jet pump surface reforming apparatus and a jet pump surface reforming method for modifying the surface of an existing jet pump installed in a boiling water reactor.

[0002]

2. Description of the Related Art Reactor water discharged from a recirculation pump flows through a jet pump at a high speed. Therefore, during the operation of the plant, a force of fluid vibration is applied to the vicinity of a welded portion of the jet pump, which may cause fatigue failure. Further, the jet pump is exposed to a high-temperature and high-pressure environment for a long period of time due to a long-term operation of the plant, and there is a concern that the jet pump may deteriorate. In particular, there is a danger of potential stress corrosion cracking due to the sensitization of the material and the formation of residual tensile stress due to heat input in the vicinity of the weld.

On the other hand, riser braces and brackets are welded to the outer surface of the jet pump. The shape of the outer surface of the welded portion is complicated, and a dedicated device is required for each portion in order to perform surface modification on the welded portion from the outer surface side of the jet pump.

Further, the welded portion between the jet pump diffuser and the elbow and the welded portion between the elbow and the thermal sleeve are close to the reactor pressure vessel, and a small dedicated device is required to modify the welded portion from the outer surface. There is a problem that it is difficult to perform surface modification.

Further, the thickness of the welded portion between the thermal sleeve and the safe end is large from the outer surface to the welded portion, and it is extremely difficult to obtain the effect of the application from the outer surface to the inner surface of the welded portion between the thermal sleeve and the safe end. It is.

[0006]

In the prior art,
In order to perform surface modification from the outer surface side of a jet pump with a complicated outer surface of the welded part, special equipment is required for each part, and the welded part between the jet pump diffuser and the elbow and the welded part between the elbow and the thermal sleeve are atomic. In order to reform the welded portion from the outer surface, which is close to the furnace pressure vessel, a small dedicated device is required, and there is a problem that the surface modification is difficult to perform. In addition, as for the welded portion between the thermal sleeve and the safe end, the thickness from the outer surface to the welded portion is large, and it is extremely difficult to obtain the effect applied from the outer surface to the inner surface of the welded portion between the thermal sleeve and the safe end. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a jet pump surface reforming apparatus and a surface reforming method for performing surface reforming of an existing jet pump from an inner surface side thereof. The purpose is to:

[0008]

According to the first aspect of the present invention, there is provided a jet pump mounted on a reactor pressure vessel of a boiling water reactor and a welded portion of the jet pump and an inner surface in the vicinity of the welded portion. A surface reforming device for a jet pump for reforming, wherein the recirculation inlet nozzle, into which the thermal sleeve of the jet pump is inserted, can be sequentially introduced from the outside of the furnace in an open state and driven on the inner surface of the pipe. And a surface reforming device for a jet pump, comprising a laser irradiation device and an inspection device.

According to the second aspect of the present invention, there is provided an operation rod which can be inserted from the outside into the recirculation inlet nozzle, a fixed arm storage portion connected to the operation rod, and a fixed arm stored in the fixed arm storage portion. A polishing tool provided on the distal end side of the fixed arm storage portion, wherein the rotary head is rotatably supported at the distal end of the fixed arm storage portion, and a riser tube, an elbow, and a thermal sleeve of a jet pump are provided. A polishing head comprising: a polishing head for polishing a safe-end welded portion and an inner surface near the welded portion; and a monitoring camera for monitoring a polishing state.

According to the third aspect of the present invention, there is provided an operation rod which can be inserted from the outside into the recirculation inlet nozzle, a fixed arm storage portion connected to the operation rod, and a fixed arm stored in the fixed arm storage portion. A laser irradiator provided on the distal end side of the fixed arm storage unit, wherein the laser irradiator is rotatably supported at the distal end of the fixed arm storage unit and is a jet pump riser tube, an elbow, A laser irradiation head for irradiating the thermal sleeve, the safe end welding portion and the inner surface near the welding portion with a laser,
An irradiation head opening / closing mechanism for putting the laser irradiation head into and out of the rotary head is provided.

According to the fourth aspect of the present invention, an operating rod which can be inserted from the outside into the recirculation inlet nozzle, a fixed arm connected to the operating rod, and a visual inspection inspection provided at a tip end side of the fixed arm. A camera and a head for penetrant testing, wherein the camera for visual inspection and the head for penetrant testing are a jet pump riser tube, an elbow,
Provided is an inspection apparatus characterized in that the entire circumference of a surface to be inspected can be inspected by rotating on a thermal sleeve, a safe end weld, and an inner surface near the weld.

In the invention according to claim 5, after the cooling water recirculation pipe is cut, the polishing device, the inspection device and the laser irradiation device according to claims 2 to 3 are inserted from the opening of the recirculation inlet nozzle. The polishing work by the polishing device and the laser irradiation by the laser irradiation device are performed on the riser pipe, elbow, thermal sleeve, and the welded portion of the safe end and the inner surface near the welded portion of the jet pump attached to the reactor pressure vessel. Thereafter, there is provided a method for modifying the surface of a jet pump, wherein the surface condition is inspected by the inspection device.

According to a sixth aspect of the present invention, in the method for modifying a surface of a jet pump according to the fifth aspect, the tensile residual stress in the vicinity of the weld is reduced or compressed by irradiating a YAG laser, or the tensile stress in the vicinity of the weld is reduced. Provided is a jet pump surface modification method characterized by preventing stress corrosion cracking by improving the metal structure.

According to the present invention, the riser brace welded to the outer surface of the jet pump, the welded portion of the bracket, the welded portion of the jet pump diffuser and the elbow, the welded portion of the elbow and the thermal sleeve, the welded portion of the thermal sleeve and the safe end, and the weld heat affected zone are formed. On the other hand, the surface tensile stress can be reduced or compressed.

In addition, a separate polishing device, an inspection device, and a laser irradiation device are not required for each of the above-mentioned portions, and a riser brace, a welding portion of a bracket, a welding portion of a vertical pipe portion of a jet pump diffuser and an elbow, and an elbow Two types of polishing equipment, inspection equipment, and laser irradiation equipment make it possible to perform surface modification on the above-mentioned welded portion of the welded portion of the horizontal sleeve portion of the thermal sleeve and the thermal sleeve and the safe end.

[0016]

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

FIG. 1 is a sectional view showing the structure of a jet pump, and FIG. 2 is a structural view showing a polishing device. FIG. 3 is a configuration diagram illustrating a laser irradiation device, and FIG. 4 is a configuration diagram illustrating an inspection device.

As shown in FIG. 1, the reactor pressure vessel 1 is provided with a recirculation inlet nozzle 2, and a thermal sleeve 4 of a jet pump 3 is connected to a safe end of the recirculation inlet nozzle 2 via a weld 4a. Communication is established. That is,
The jet pump 3 includes a thermal sleeve 4 attached to the reactor pressure vessel 1, an elbow 5 welded to the thermal sleeve 4, and a riser pipe 6 welded to the elbow 5. A bracket 7 and a riser brace arm 8 are welded to an outer surface of the bracket.
In a normal state, a reactor recirculation pipe (not shown) is connected to the outer end of the recirculation inlet nozzle 2.

In the present embodiment, with the reactor recirculation pipe cut from the outside of the reactor pressure vessel 1, a device described later is inserted from outside the recirculation inlet nozzle 2 opened by cutting the recirculation pipe. The reforming is performed.

FIG. 2 shows the configuration of a polishing apparatus used for cleaning performed at the beginning of the reforming operation. That is, as shown in FIG. 2, the polishing device 9 connects a fixed arm storage portion 11 as a cylindrical case body to an operation rod 10 for inserting the recirculation inlet nozzle 2 from outside. A fixed arm, which will be described later, for fixing the device is stored in the fixed arm storage unit 11 and the fixed arm storage unit 1
1 has a configuration in which a rotary head 12 provided with a polishing tool or the like is connected to the tip side.

A central shaft 13 is provided in the cylindrical fixed arm storage portion 11, and a total of three sets of fixed arms 14, one set each of two front and rear bodies which can be raised and lowered toward the periphery thereof, are fixed support points. 15 and is mounted so as to be openable and closable at equal intervals in the circumferential direction. Each of these fixed arms 14
Is provided with a nozzle inner surface contact portion 16 such as a roller, for example. Each fixed arm 14 is connected to a drive rod 19 of a telescopic cylinder 18 supported in a fixed arm storage part 11 via a rotary arm 17. , And moves back and forth between the inner and outer peripheries of the fixed arm storage section 11. Thereby, each fixed arm 14
Abuts on the inner peripheral surface at a predetermined position such as the thermal sleeve 4 in the recirculation inlet nozzle 2 and can be fixed.

The rotary head 12 is formed as a case body rotatably supported around the axis via a joint portion 21 at the end of the center shaft 13 of the fixed arm storage portion 11.
The rotary head 12 includes a driving cylinder 23 and an X
The polishing head 22 is supported by a polishing head expansion / contraction mechanism 25 including a telescopic link arm 24 having a rectangular shape, and a monitoring camera 26 is housed. That is, the rotating head 12
Is a polishing head 22 that rotates and performs a polishing operation, and a polishing head telescopic mechanism 2 that presses the polishing head 22 against a construction target portion.
5 and a monitoring camera 26 for monitoring the construction state. At the time of use, the polishing device 9 is inserted to a predetermined position using the operation rod 10, and the three fixed arms 14 are extended and fixed to the inner surface of the thermal sleeve 4, and then stored in the rotary head 12. The polished head 22 can be pressed against the construction target portion by extending the polished head extension mechanism 25.

Then, the wire brush is brought into close contact with the inner peripheral surface of the thermal sleeve 4 or the like, and by rotating the rotary head 12 as a whole, it is possible to remove the adhering substances adhered to the inner surface of the thermal sleeve 4 or the like. I have. The monitoring camera 13 checks the state after the removal.

The polishing head 22 is stored after confirming that the deposits have been removed. First, after the fixed arm 14 is stored in the fixed arm storage section 11, the operating rod 10 is operated to polish the polishing device 9 to the open end 2a of the recirculation inlet nozzle 2.
Can be removed more outward.

Next, FIG. 3 shows a laser irradiation apparatus which can be inserted from the open end 2a of the recirculation inlet nozzle 2. The laser irradiator 35 irradiates a laser to the weld heat affected zone and its vicinity.

That is, the laser irradiating device 35 has the same operating rod 10 as the polishing device 9, the fixed arm storing section 11, and the fixed arm 14, and has a laser irradiating head 36 and a laser irradiating head 36 at its tip. Irradiation head opening and closing mechanism 20 for taking in and out
And can be inserted into a predetermined position on the inner peripheral surface of the thermal sleeve 4 and the like.
It can be fixed through. The laser irradiation head 36 is deployed from the rotary head 12 by using the irradiation head opening / closing mechanism 20 and set at a predetermined position.
The rotary head 12 is provided with a guide roller, and has a function of maintaining a constant laser beam focus distance. After the setting is completed, the rotary head 12 is rotated to irradiate the entire surface of the inner surface of the thermal sleeve 4 or the like with a laser, and the inner surface of the tube at the target portion is subjected to surface treatment by heating.
The residual stress on the inner surface of the tube can be improved by heating by the laser irradiation. Since the fixed arm 14 and the like of the laser irradiation device 35 are substantially the same as those shown in FIG. 2, the corresponding portions in FIG. 3 are assigned the same reference numerals as in FIG.

FIG. 4 shows an inspection apparatus 27 which can be inserted into the recirculation inlet nozzle 2 after the completion of laser irradiation to check the inner surface state after laser irradiation. This inspection device 27
Is an operation rod 10 similar to the above, and this operation rod 10
And three sets of fixed arms 14 supported via a support shaft 28 which can be extended and retracted. The fixed arm 14 is provided with a nozzle inner surface contact portion 16 such as a roller. The inspection device 27 includes an inspection device main body 29 provided on the operation rod 10 and a guide roller 31 supported by the oblique shaft 30.
And an inspection head 34 provided with a camera 32 for appearance inspection and a head 33 for penetration inspection, so that both the appearance inspection and the penetration inspection can be performed.

The inspection apparatus main body 29 can be inserted up to a predetermined position in the thermal sleeve 4, and the apparatus can be fixed using a fixing arm 14 for fixing the apparatus and a guide roller 31. After fixing the inspection apparatus main body 29 in this way, the laser irradiation unit is inspected using the appearance inspection camera 32. The visual inspection camera 32 and the penetrating inspection head 33 are connected to the inspection head 34 about the axis of the tube.
By rotating by 60 degrees, the entire inner surface of the thermal sleeve 4 and the like can be inspected.

The penetrating inspection head 33 is used for a penetrating inspection test. The penetrating inspection head 33 is used to recirculate a cleaning solution and a developing solution through the opening end 2 a of the inlet nozzle 2.
It can be supplied from outside. Further, the inspection camera is capable of observing and inspecting the test location after the development processing of the penetration test by the penetration test head 33 is completed.

Next, the operation will be described. In this embodiment,
A remote control device (not shown) is provided, and the following operations can be automatically performed remotely.

In the reforming operation, first, as shown in FIG. 1, the water level in the reactor is lowered to just below the upper portion of the jet pump 3 and then the reactor recirculation pipe (not shown) connected to the recirculation inlet nozzle 2. From the outside of the reactor pressure vessel 1. Then, the polishing device 9 shown in FIG. 2 is inserted from the opening end 2a of the recirculation inlet nozzle 2 opened by cutting the reactor recirculation pipe. Next, after inserting the polishing device 9 to a predetermined position, first, the three sets of fixed arms 14 are extended,
It is fixed to the inner surface of the thermal sleeve 4. After fixing the thermal sleeve 4, the polishing head 22 stored in the rotary head 12 is pressed against the construction target portion by extending the polishing head extension mechanism 25.

Then, after the wire brush of the polishing head 22 is brought into close contact with the inner surface of the thermal sleeve 4, the rotating head 1
2 is rotated to remove the deposits attached to the inner surface. The condition after removal is confirmed by a surveillance camera,
After confirming that the adhering matter has been removed, polish head 2
After storing the fixed arm 14 and storing the fixed arm 14, the polishing device 9 is removed from the open end 2a of the recirculation inlet nozzle 2.

Next, the laser irradiation device 35 shown in FIG. 3 is inserted from the opening end 2a of the recirculation inlet nozzle 2 to irradiate the laser to the heat affected zone and its vicinity. In this case, after inserting the laser irradiation device 35 at a predetermined position in the thermal sleeve 4, the three sets of fixed arms 14 are extended,
The laser irradiation device 35 is fixed to the inner surface of the thermal sleeve 4. Then, the laser irradiation head 36 is deployed from the rotary head 12 by using the irradiation head opening / closing mechanism, and is set at a predetermined position. After the setting of the laser irradiation head 36 is completed, the rotary head 12 is rotated to irradiate the entire circumference of the thermal sleeve 4 with a laser to perform a surface treatment of a target portion.

After the laser irradiation is completed, the inspection device 27 shown in FIG. 4 is inserted to check the inner surface state after the laser irradiation. After inserting the inspection device main body 29 into the thermal sleeve 4 to a predetermined position, the device is fixed using the fixing arm 14 and the guide roller. After fixing the device, the laser irradiation unit is inspected using the visual inspection camera 32.
Next, a penetrating inspection test is performed using the penetrating inspection head 33, and after the development processing is completed, the presence or absence of a flaw is inspected by observing the surface of the part using an appearance monitoring camera 32. After the above series of work is completed, the piping is restored.

According to the embodiment described above, the welded portion of the jet pump 3 whose outer surface has a complicated shape is irradiated with YAG laser from the inner surface to reduce the residual tensile stress on the inner surface or to reduce the compression. can do. In addition, the structure of the inner surface can be improved, and the occurrence of stress corrosion cracking can be effectively prevented.

Further, since the above operation can be performed from the inside of the thermal sleeve 4 by inserting the device from outside the furnace, the operation is easy. Also, there are only two types of devices, one for the vertical tube portion and one for the horizontal tube portion, and a dedicated device is not required for each welded portion, so that the device configuration is extremely simple.

[0037]

As described above in detail, according to the present invention, it is possible to reduce or compress the tensile residual stress on the inner surface by irradiating the inner surface of the jet pump with a laser from the inner surface. Can be improved, and the occurrence of stress corrosion cracking can be prevented.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a configuration diagram of a jet pump.

FIG. 2, showing an embodiment of the present invention, is a configuration diagram of a polishing apparatus.

FIG. 3, showing an embodiment of the present invention, is a configuration diagram of a laser irradiation apparatus.

FIG. 4 shows one embodiment of the present invention, and is a configuration diagram of an inspection apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reactor pressure vessel 2 Recirculation inlet nozzle 3 Jet pump 4 Thermal sleeve 5 Elbow 6 Riser pipe 7 Bracket 8 Riser brace arm 9 Polishing device 10 Operating rod 11 Fixed arm storage part 12 Rotating head 13 Center axis 14 Fixed arm 15 Fixed fulcrum Reference Signs List 16 Nozzle inner surface contact part 17 Rotating arm 18 Telescopic cylinder 19 Drive rod 20 Irradiation head opening and closing mechanism 21 Joint part 22 Polishing head 23 Driving cylinder 24 Telescopic link arm 25 Polishing head telescopic mechanism 26 Monitoring camera 27 Inspection device 28 Telescopic Possible support shaft 29 Inspection device main body 30 Oblique axis 31 Guide roller 32 Appearance inspection camera 33 Penetration inspection test head 34 Inspection head 35 Laser irradiation device 36 Laser irradiation head

Claims (6)

[Claims] 1. A jet pump surface reforming apparatus for reforming a welded portion and an inner surface near a welded portion of a jet pump attached to a reactor pressure vessel of a boiling water reactor,
A recirculation inlet nozzle in which the thermal sleeve of the jet pump is inserted is opened, and a polishing device, a laser irradiation device, and an inspection device are provided, which can be sequentially introduced into the opening from outside the furnace and driven on the inner surface of the tube. A surface reforming device for a jet pump, comprising: 2. An operation rod that can be inserted from the outside into the recirculation inlet nozzle, a fixed arm storage connected to the operation rod, a fixed arm stored in the fixed arm storage, and the fixed arm storage. A polishing tool provided at the distal end of the jet pump, wherein the rotary head is rotatably supported at the distal end of the fixed arm storage part, and the riser pipe, elbow, thermal sleeve, safe end welding part, and A polishing head for polishing the inner surface near the weld,
A polishing apparatus comprising: a monitoring camera that monitors a polishing state. 3. An operation rod that can be inserted from the outside into the recirculation inlet nozzle, a fixed arm storage connected to the operation rod, a fixed arm stored in the fixed arm storage, and the fixed arm storage. A laser irradiating device provided at the distal end of the jet pump, wherein the laser irradiating device is rotatably supported at the distal end of the fixed arm storage portion, and is provided with a riser pipe, an elbow, a thermal sleeve, and a safe end welding of a jet pump. A laser irradiation apparatus, comprising: a laser irradiation head for irradiating a laser beam on an inner surface near a part and a welded part; and an irradiation head opening / closing mechanism for putting the laser irradiation head into and out of a rotary head. 4. An operation rod which can be inserted from the outside into the recirculation inlet nozzle, a fixed arm connected to the operation rod, a camera for visual inspection and a penetrating inspection test provided on the distal end side of the fixed arm. A head and a head for penetrant inspection, the entire surface to be inspected by rotating on the riser pipe, elbow, thermal sleeve, safe end welded portion of the jet pump and the inner surface near the welded portion. An inspection device characterized in that the circumference can be inspected. 5. After cutting the cooling water recirculation pipe, insert the polishing device, the inspection device and the laser irradiation device according to claim 2 through the opening of the recirculation inlet nozzle,
After the riser pipe of the jet pump attached to the reactor pressure vessel, the elbow, the thermal sleeve, the welded portion of the safe end and the inner surface near the welded portion, after the polishing work by the polishing device and the laser irradiation by the laser irradiation device, A surface reforming method for a jet pump, wherein a surface condition is inspected by the inspection device. 6. The method for modifying a surface of a jet pump according to claim 5, wherein the step of irradiating a YAG laser reduces or reduces tensile residual stress in the vicinity of the weld, or improves the metal structure in the vicinity of the weld. A method for modifying the surface of a jet pump characterized by preventing stress corrosion cracking.