JP2003337192A - Inspection preventive maintenance device and inspection method for reactor pressure vessel internal structure - Google Patents

Abstract

(57) [Summary] To improve the efficiency of inspection and preventive maintenance work of a furnace bottom part of a reactor pressure vessel and an annulus formed between a core shroud and the reactor pressure vessel. The structure of a reactor pressure vessel filled with cooling water is accessed by remote control to check the structure,
An inspection and preventive maintenance device for a reactor pressure vessel internal structure that performs cleaning and preventive maintenance, the inspection and preventive maintenance device holding and fixing itself to the pressure vessel internal structure or a guide pipe that guides itself. It comprises a mechanism part and a body part having a plurality of joints movably and detachably attached to the fixed mechanism part, wherein the body part has a nozzle 436 for generating cavitation bubbles, and an electronic part for monitoring a construction part. A camera and lighting means 437 were provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection preventive maintenance device and inspection method for internal structures of a reactor pressure vessel, and particularly to an internal structure of a reactor pressure vessel in which cooling water is filled in the reactor pressure vessel. The present invention relates to an inspection preventive maintenance device and an inspection method for a structure in a reactor pressure vessel, which is accessed by remote control to inspect and prevent the structure.

[0002]

2. Description of the Related Art Conventionally, the inspection of a reactor pressure vessel and reactor internals during the service period of a nuclear power plant is disclosed in Japanese Patent Application Laid-Open No. 7-69284 "Swimming Underwater Visual Observation Device" or Japanese Patent Application Laid-Open No. 11-14784. As shown in Japanese Patent Laid-Open Publication "Inspection apparatus for nuclear reactor", it is performed using an apparatus having only a camera function.

Further, the preventive maintenance by improving the residual stress of the reactor pressure vessel and the internal structure of the reactor is described in Japanese Patent No. 28419.
No. 63 "Method for improving residual stress of reactor structure and its residual stress measuring device", Japanese Patent No. 2824610 "Water jet peening method and its device" or Japanese Patent No. 2859125 "Preventive maintenance method in reactor vessel and its As shown in "Preventive maintenance device", a device provided with a nozzle for generating cavitation bubbles is used.

Further, when performing a residual stress improving work on an annulus portion such as a shroud support in a reactor pressure vessel, a CRD (control rod drive mechanism) housing, a CRD stub tube, an ICM (neutron measurement) housing and a reactor bottom, Japanese Patent No. 2841963 "Method for improving residual stress of nuclear reactor structure and residual stress measuring device thereof", Japanese Patent No. 2824
As shown in No. 610 “Water jet peening method and its apparatus” or Japanese Patent No. 2859125 “Preventive maintenance method and its preventive maintenance apparatus in reactor vessel”, it depends on the output size of the nuclear power plant, After removing 1/4 or more of the 102 to 240 CRDs, CRs (control rods) and CR guide tubes, the device is seated on the upper surface of the CRD housing for installation.

[0005]

The above-mentioned conventional inspection or preventive maintenance device does not have a cleaning function for the surface to be inspected. Therefore, if the clad or the like is attached to the surface to be inspected, it is necessary to remove the clad in advance by a separate device or means. For this reason, the work process including the confirmation work before and after the work becomes complicated, and the opportunity of being exposed to the worker increases.

Further, since the shroud support welded portion, the welded portion between the shroud support and the support leg, the welded portion between the support leg and the reactor pressure vessel bottom portion, etc. are narrow, the accessibility is deteriorated. Therefore, it was practically impossible to carry out the residual stress improvement work as a preventive maintenance measure during the periodic inspection of the nuclear power plant.

The present invention makes it possible to improve the efficiency of inspection and preventive maintenance work of the reactor bottom and the annulus portion formed between the core shroud and the reactor pressure vessel, and shorten the working time. Provide a preventive maintenance system that can inspect internal structures of a reactor pressure vessel.

[0008]

The present invention adopts the following means in order to solve the above problems.

Inspecting the reactor pressure vessel structure filled with cooling water by remote control,
An inspection preventive maintenance device for a reactor pressure vessel internal structure for cleaning and preventive maintenance, the inspection preventive maintenance device holding and fixing itself to the pressure vessel internal structure or a guide pipe for guiding itself. An electronic camera for observing a mechanical section and a main body having a plurality of joints movably and removably attached to the fixed mechanical section, the main body comprising a nozzle for generating cavitation bubbles and a construction section. And lighting means. Further, the inspection preventive maintenance device can be detachably attached to the fixing mechanism portion.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a view for explaining a nuclear reactor and a reactor internal structure which are the subject of the present invention, and here shows a pressure vessel 1 of a boiling water type light water reactor and its internal structure. As shown in the figure, a dryer 2, a separator 3, and a core shroud 4 are installed in a reactor pressure vessel 1, and a fuel assembly 7 is installed in the core shroud 4.
An upper grid plate 5, a core support plate 6 and the like for supporting the reactor are attached.

A recirculation water outlet nozzle 8 is attached to the lower portion of the reactor pressure vessel 1, and a baffle plate 10 and a welded to the baffle plate 10 are welded to a space surrounded by the pressure vessel 1 and the core shroud 4. A jet pump 9 is arranged. An annular narrow cylindrical space surrounded by the reactor pressure vessel 1 and the core shroud 4 and in which the jet pump 9 is installed is called an annulus portion 11.

Further, a CRD housing 12, a CRD stub tube 13, and an ICM are provided at the bottom of the reactor pressure vessel 1.
The housing 14 is welded. The bottom of the reactor pressure vessel 1 where the CRD housing 14 stands is called a reactor bottom 15. Further, the core shroud 4 is supported by a shroud support leg 16 and a shroud support 17 which are welded to the furnace bottom portion 15.

FIG. 2 is a view for explaining the inspection and preventive maintenance procedure performed by the inspection and preventive maintenance device for the reactor pressure vessel internal structure according to this embodiment, and FIG. 3 is for explaining the setting of the guide pipe. The inspection and preventive maintenance of the furnace bottom and the annulus will be described below with reference to FIGS.

First, in step 1, the RPV (pressure vessel) head is removed, and in step 2, the reactor well is filled with water. Then, in step 3, the dryer 2, separator 3 and other in-reactor equipment and the fuel assembly. 7 is removed, and in step 4, the water in the reactor well 19 is drained.

In step 5, the reactor water level is set to RP.
Lower to the V-flange surface, and install a scaffold consisting of, for example, a shield 22 on the RPV flange surface to cover the entire flange,
In step 6, from the shield 22 to the guide pipe 2
1 is suspended in the furnace, and the guide pipe 21 is held by the shield 22. In addition, when suspending the inspection preventive maintenance device using the built-in refueling cart, it is not necessary to install the shield and the guide pipe. Therefore, since the well is not drained, steps 4 to 6 can be omitted.

In step 7, the lift truck 2 to be described later
An inspection preventive maintenance device 25 for inspecting preventive maintenance of the shroud support part is attached to 4 and is suspended in the furnace. The lifting carriage 24 has a structure that moves up and down along a rail attached to the inner surface of the guide pipe 21.

In step 8, after the apparatus is installed at a predetermined position, for example, high-pressure water is jetted from a WJ (water jet) nozzle, laser irradiation from a laser oscillator,
The target surface is constructed by a method capable of generating cavitation such as ultrasonic irradiation from an ultrasonic transducer. That is, by irradiating the target surface with the collapse pressure of cavitation, the clad on the target surface can be removed, and at the same time, the residual stress on the target member surface can be converted into compressive stress. In step 9, the target weld is inspected by VT inspection (visual inspection by an electronic camera). In the present embodiment, as will be described later, it is possible to use a device for removing the clad, a device for improving the residual stress, and a device for performing the VT inspection all in one device.

If no defect is detected in the VT inspection in step 9, the preventive maintenance of the target site has already been completed by the work such as WJ, laser, ultrasonic wave, etc. performed in step 8, so the process proceeds to step 13. . Note that in step 8, the target site may be directly polished with a flapper or a brush to clean the target site and generate the compressive residual stress.

If a defect is detected in the VT inspection in step 9, in step 11, the location of the defect,
After the size is specified, in step 12, the defect is removed or repaired.

In step 13, restoration work is started. In step 14, the inspection preventive maintenance device is removed from the pressure vessel, and in step 15, the guide pipe 2
1 and the cable processing device 20 are removed, and the shield 22 is removed. In step 16, water is poured into the reactor well 19, the removed reactor internal equipment is restored in step 17, the water in the reactor well 19 is drained in step 18, and the RPV head 18 is attached in step 19.

4 and 5 are views showing an inspection / preventive maintenance device, FIG. 4 is a view showing the entire inspection / preventive maintenance device, and FIG. 5 is a WJP (water jet) attached to a lower arm of the inspection / preventive maintenance device. FIG. 6 shows a peening nozzle 436 and an underwater camera and underwater illumination 437. As shown in the figure, this device 25 comprises a lift truck 24 whose position can be fixed by means such as a clamp, and a main body of an inspection / preventive maintenance device. The main body comprises an arm rotation drive shaft and an arm vertical drive shaft. , The upper arm swing shaft, the lower arm swing shaft, the wrist swing drive shaft, and the nozzle swing drive shaft.

The arm swivel drive shaft 41 is driven by an arm swivel drive motor 47 with a speed reducer via a gear to provide a pinion 48.
Is rotated, and the swivel spindle 49 to which the pinion 48 is attached is swung to swivel the entire arm including the arm vertical drive unit 42 below the swivel spindle 49.

Further, the arm vertical drive unit 42 is driven by an arm vertical drive motor 411 with a speed reducer to move the vertical feed screw 412.
The slider 413 is moved up and down by driving. As the slider moves up and down, the arm vertical drive unit 42 moves in the vertical direction.

The upper arm 414 is attached to the arm vertical drive unit 42, and the upper arm 414 is moved up and down by moving the slider of the vertical drive unit up and down.

The upper arm drive is an upper arm swing motor 415 with a reduction gear.
Through the pinion 416 and the worm gear 417,
The pulley 418 attached to the worm gear 417 is rotated, and the pulley 421 attached to the upper arm swing shaft 419 is rotated by the timing belt 419.
Is transmitted to the upper arm 414 to swing.

The lower arm drive is a lower arm swing motor 422 with a reduction gear.
Through the pinion 423 and the worm gear 424,
The pulley 425 attached to the worm gear 424 is rotated, and the rotation of the pulley 425 is changed to the pulley 428 attached to the lower arm swing shaft 427 by the timing belt 426.
The lower arm 429 is swung by being transmitted to.

In the wrist turning drive, a pinion 431 is rotated by a wrist turning drive motor 430 with a speed reducer, and a wrist turning main shaft 432 to which the pinion 431 is attached is rotated to cause WJP below the wrist turning main shaft 432.
The entire nozzle swing drive is swung. Nozzle swing drive is performed by a nozzle swing drive motor 433 with a speed reducer.
By rotating 34, the nozzle swing shaft 435 is rotated. Thereby, the WJP nozzle 436, the underwater camera and the underwater illumination 437 attached to the nozzle swing shaft 435 are rotated.

In this way, the inspection / preventive maintenance device 25 for inspecting and performing preventive maintenance of the furnace bottom and the annulus has a multi-joint structure, and by simultaneously controlling the operation of several joints, the shroud support 17 and the shroud support leg are controlled. It is possible to inspect, clean, and preventatively maintain the inner / outer surface welded portion with 16 and the inner / outer surface welded portion between the support leg and the bottom of the reactor pressure vessel.

In FIG. 5, at the tip of the lower arm portion, a WJP nozzle 43 for cleaning the target surface and applying a compressive stress thereto.
6 and underwater camera and underwater illumination 437 for inspecting the plane of symmetry. The WJP nozzle 436 is connected to the high-pressure water supply pipe 51 via the swivel joint 52, and can rotate arbitrarily. Further, the motor 53 allows the swivel joint 52 to be rotated by remote control. By attaching an ultrasonic wave oscillating element or a laser oscillating device instead of the nozzle 436, it is possible to clean the target site by cavitation generated by using ultrasonic waves or a laser.

FIG. 6 is a view for explaining a construction state by the inspection preventive maintenance device. As shown in the figure, the upper arm 4 of the device
By controlling the lower arm 14 and the lower arm 429, it is possible to access and construct an arbitrary place. For example, when constructing the lower surface welded portion 61 called “H8” in the nuclear reactor, the positions of the upper arm 414 and the lower arm 429 are controlled so that the nozzle portion connected to the lower arm 429 faces directly above. Then, the nozzle 436 can be installed diagonally. Also, when installing a shroud support leg,
The lower arm is controlled so that the nozzle portion faces downward. Next, the nozzle is directed toward the H11 welding line 62 in the oblique direction, and the swing main shaft 49 of the present apparatus is further rotated. At that time, the H11 welding line 62 can be constructed by controlling the other axes at the same time. The tip of the guide pipe 21 is CR.
The upper arm portion and the lower arm portion can be fitted and fixed to the D housing 12, and the upper arm portion and the lower arm portion can be projected from the opening formed in the guide pipe.

FIG. 7 is a top view of the annulus portion of the nuclear reactor. As shown in the figure, there are many interfering substances, so it is very difficult to insert the inspection and preventive maintenance device from this part and lower it to the bottom of the furnace. Therefore, by using a flexible guide pipe 71 as described later, it is possible to more easily put the device into the narrow space. In the case of the figure,
12 locations shown in the figure (15 °, 45 °, 75 °, 10
5 °, 135 °, 165 °, 195 °, 225 °, 25
5 °, 285 °, 315 °, 345 ° positions), by inserting the flexible guide pipe 71 and lowering the device along the guide pipe, a shroud support welded portion, a shroud support and a shroud support leg, etc. It can be applied to welded parts.

FIG. 8 is a diagram for explaining the insertion of the flexible guide pipe and the inspection preventive maintenance device. The insertion and the insertion are performed according to the procedure shown in FIG. First, the RPV head 18 of the reactor is removed and the reactor is opened. Next, the in-core device and the fuel assembly 7 are removed. The fuel assembly 7 to be removed at this time can be provided only in the vicinity of the inspection target portion. Next, the water in the reactor well 19 is drained, and then the guide pipe installation jig 56 is installed on the upper surface of the flange of the shroud 4.

Next, the water level in the reactor is lowered to the RPV flange surface, a shield 57 is installed on the RPV flange surface to cover the entire flange, and the flexible guide pipe 71 is passed from the shield 57 to the guide pipe installation jig 56. Then, it is hung down to a predetermined level of the annulus portion 11. The guide pipe can be installed in another supportable structure instead of the shield 57.

Next, a second embodiment will be described with reference to FIGS. 9 to 13. 9 and 10 are views showing a procedure for inserting the inspection and preventive maintenance device from the upper part of the furnace and installing it on the jet pump 9. To the flexible guide pipe 71 installed by the above-mentioned method, four wire ropes 91 are attached as insertion guides in order to keep the orientation of this device constant. Furthermore, this wire rope 9
An insertion jig 94 of the present apparatus, which is provided with a guide pipe inner surface clamp mechanism 92 and a furnace inner clamp mechanism 93, is attached to the apparatus 1. The main body 62 of the inspection and preventive maintenance device is attached to the tip of the device insertion jig 94, and it is suspended in the furnace. Since the wire ropes 91 pass through the four corners of the device insertion jig 94,
The device insertion jig 94 can be lowered to the lower end of the guide pipe 71 without changing the orientation.

As shown in FIG. 10a, the guide pipe 71
The device insertion jig 94 that has descended to the lower end of the ball is rotated by rotating the ball screw 97 by the guide pipe inner surface clamp drive motor 96 and moving the ball screw nut 98 up and down.
Driving the link 99, the pipe inner surface clamp pad 910
To the outside and clamp the inner surface of the guide pipe 71,
This allows you to hold your own posture.

Next, as shown in FIG. 10B, by driving the in-reactor clamp mechanism turning shaft 911, the in-reactor clamp mechanism 93 is turned 90 °, and the clamp pad 912 of the in-reactor clamp mechanism 93 is moved to the shroud 4. The orientation is changed so that it can be clamped to the inner surface of the reactor pressure vessel 1.
After that, the positioning clamp drive motor rotates the ball screw 88 to move the ball screw nut 87 up and down, thereby driving the link 917 and in-core clamping mechanism 93.
The inner clamp pad 912 is bulged outward and clamped between the shroud 4 and the inner surface of the reactor pressure vessel 1.
Thereby, the position and orientation of the mechanical swing cylinder 913 can be maintained.

Next, as shown in FIG. 10C, the mechanical swing cylinder 913 and the inspection / preventive maintenance device 62 are turned to the jet pump 9 by driving the mechanical swing portion turning shaft 95.

Next, as shown in FIG. 10d, the link 918 is driven by driving the mechanical swing cylinder 913.
The inspection preventive maintenance device 62 is pressed against the jet pump 9 via. Here, the jet pumps are attached to the front part (lower arm part) and the rear part (upper arm part) of the main body 62 of the inspection and preventive maintenance device, and the main body 62 is attached to the jet pump 9.

Next, as shown in FIG. 10e, the mechanical connection cylinder 919 is turned off to separate the front part (lower arm part) and the rear part (upper arm part) into a self-supporting walking part. Then, the self-supporting walking section, that is, the main body section 62 is advanced to a predetermined working position.

FIG. 11 is a view showing a fixed portion and a main body portion of the inspection preventive maintenance device. Although the object to which the main body portion 62 is attached is changed from the jet pump to the reactor pressure vessel, the attachment procedure is the same as that shown in FIGS. 9 and 10.

FIG. 12 and FIG. 13 are diagrams for explaining the independent walking of the main body portion 62 of the inspection and preventive maintenance device. Body 62
WJP for cleaning the target surface and applying compressive stress
It is composed of a nozzle, a nozzle head portion 121 in which a camera for inspection is arranged, and a walking swiveling expansion / contraction portion 122. Also,
The walking swiveling expansion / contraction unit 122 includes a rear suction pad 131 and a rear pad lifter 123, a front / rear movement cylinder 124, a front pad lateral shift drive unit, a link 125, a front suction pad 126, and a front pad lifter 127.

The nozzle head section 121 includes a nozzle head lateral swing drive section, a nozzle swing drive section, and a WJP nozzle 12.
8 and underwater camera and underwater lighting 129.

First, as shown in FIG. 13A, the front pad lifter 127 separates the front suction pad 126 from the suction surface. Next, as shown in FIG. 13b, the link 125 is swung via the worm gear 130 by the front pad lateral shift drive motor. Next, as shown in FIG. 13c, the front-rear moving cylinder 124 is moved forward to turn off the front pad lifter 127 to set the front suction pad on the suction surface, and then the suction of the front suction pad 126 is turned off.
Set to N. Next, as shown in FIG. 13D, the rear pad lifter 123 separates the rear suction pad 131 from the suction surface. Next, as shown in FIG. 13e, by rotating the link 125 via the worm gear 130 by the front pad lateral shift drive motor, the rear pad portion is pulled toward the front pad, and the rear pad lifter 123 is opened.
By performing F, the rear suction pad 131 is set on the suction surface, and then the suction of the rear suction pad 131 is turned on. By the above operation, the main body 62 can be moved laterally. The nozzle head 121 is
The nozzle head lateral swing drive motor 132 can laterally swing the WJP nozzle 128, the underwater camera, and the underwater illumination 129 via the worm gear 133. Further, the nozzle swing drive motor 134 can swing the WJP nozzle 128, the underwater camera and the underwater illumination 129 up and down via the worm gear 135. This will allow you to inspect, clean, and
Preventive maintenance is possible.

Next, a third embodiment will be described with reference to FIGS. 14 to 15. Figure 14 shows the CRD of the bottom of the reactor
FIG. 15 is a view showing an inspection preventive maintenance device capable of performing inspection, cleaning and preventive maintenance of a welded portion of a cylindrical structure such as a housing, a CRD stub tube and an ICM housing.
Is a top view thereof. This apparatus has a total of four parallel link type clamp arms 143, one pair each on the left and right sides of the main body. This clamp arm is stored in a folded state when the device is put into or removed from the furnace, but when the device is installed at the bottom of the furnace, it is extended to the front and then the CRD housing 141 is held and clamped from both sides. can do.

The upper clamp portion 143a and the lower clamp portion 143b are each constituted by the left and right clamp arms as described above, and below the lower clamp portion 143b, a WJP nozzle for cleaning the target surface and further applying a compressive stress, And the nozzle head part 144 in which the camera for inspection is arranged is installed. When moving the main body, for example, the lower clamp arm 143 is projected toward the CRD housing in the direction in which the main body is to be transferred, the CRD housing 141 is clamped, and then the upper clamp is released to move between the CRD housings.

When the main body is installed in the furnace, the shield 22 and the guide pipe 21 are used, or the shield 21 and the guide pipe 21 are not used, and the crane and the like are installed. There is a method of using only the guide pipe 21 and the guide pipe 21, but the main procedures of attachment and detachment are the same as those shown in FIG.

A driving rubber roller 144 is provided at the base of the clamp arm, and the same CR is used for the upper and lower clamp arms.
After clamping the D housing 141, the main body can be swung around the CRD housing 141 by rotating the rubber roller with a motor. When working, for example, the upper and lower CRD housings 141 are the same.
With the nozzle clamped, the nozzle is swung up and down to adjust the position and WJP construction is carried out. Further, these clamp arms are provided with rack gears, and are structured to open and close by rotating them with other gears. The clamp arm has a structure in which the link operates and folds in the open state.

As described above, according to the present invention, the underwater VT function, the UT (ultrasonic flaw detection) function, the cleaning function for removing the clad on the inspection target surface, and the preventive maintenance for applying the compressive residual stress to the inspection target surface. Using the main unit with functions,
Reactor pressure vessels or reactor internals can be inspected, cleaned and preventatively maintained.

Further, the main body apparatus includes (1) a device for an annulus weld portion formed between the core shroud and the reactor pressure vessel, (2) a shroud support weld portion, and a weld between the shroud support leg and the shroud support. (3) CRD housing, CR for welding part such as a welding part between the bottom part and the support leg and the bottom part of the reactor pressure vessel
It can be manufactured separately from the device for the furnace bottom welding part such as the D stub tube and the ICM housing.

Therefore, it becomes possible to provide one main unit with cleaning, inspection, and preventive maintenance functions.
As a result, the number of times the main body device is inserted and set in the pressure vessel can be reduced, and the steps for cleaning, inspection, and preventive maintenance can be shortened.

Also, by inserting and setting the main body device using the guide pipe, quick and accurate positioning can be performed, the device can be easily accessed to the inspection and preventive maintenance target surface, and the welding portion can be inspected and cleaned. Further, the preventive maintenance process can be further shortened. Further, it is possible to reduce the detached portion of the internal structure of the furnace, which can shorten the process.

[0052]

As described above, according to the present invention, the inspection and preventive maintenance work of the reactor bottom and the annulus formed between the core shroud and the reactor pressure vessel can be performed with high efficiency. And work time can be shortened.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a nuclear reactor and a reactor internal structure to which the present invention is applied.

FIG. 2 is a diagram illustrating a procedure of inspection and preventive maintenance.

FIG. 3 is a diagram illustrating setting of a guide pipe.

FIG. 4 is a diagram showing an entire inspection / preventive maintenance device according to the first embodiment.

[Fig. 5] WJP attached to the lower arm of the inspection preventive maintenance device
It is a figure which shows a nozzle underwater camera and underwater illumination.

FIG. 6 is a diagram illustrating a construction state by the inspection preventive maintenance device.

FIG. 7 is a top view of the annulus portion.

FIG. 8 is a diagram illustrating insertion of a flexible guide pipe and insertion of an inspection and maintenance device.

FIG. 9 is a diagram showing a procedure of inserting the inspection / preventive maintenance device according to the second embodiment and installing it in the jet pump.

FIG. 10 is a diagram showing a procedure of inserting the inspection preventive maintenance device and installing the inspection preventive maintenance device in a jet pump.

FIG. 11 is a diagram illustrating a fixed portion and a main body portion of the inspection preventive maintenance device.

FIG. 12 is a diagram for explaining the independent walking of the main body.

FIG. 13 is a diagram for explaining the independent walking of the main body.

FIG. 14 is a diagram showing an entire inspection / preventive maintenance device according to a third embodiment.

FIG. 15 is a top view of the inspection and preventive maintenance device.

[Explanation of symbols]

1 Reactor pressure vessel 2 dryer 3 separator 4 core shroud 5 Upper lattice plate 6 Core support plate 7 Fuel assembly 8 Recirculation outlet nozzle 9 Jet pump 10 baffle plate 11 annulus section 12 CRD housing 13 CRD stub tube 14 IMC housing 15 core 16 shroud support legs 19 wells 21 Guide pipe 22 Shield 24 Lifting cart 25 Inspection preventive maintenance device 41 Arm rotation drive axis 49 Turning spindle 62 Inspection and preventive maintenance device body 71 Flexible guide pipe 143a Upper clamp arm 143b Lower clamp arm 414 upper arm 429 Lower arm 436 WJP nozzle 437 Underwater camera and underwater lighting 912 Clamp pad 919 Mechanical connection cylinder

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsuhiko Hirano             3-1-1 Sachimachi, Hitachi City, Ibaraki Prefecture Stock Association             Hitachi, Ltd. Nuclear Business Division (72) Inventor Ren Morinaka             3-1-1 Sachimachi, Hitachi City, Ibaraki Prefecture Stock Association             Hitachi, Ltd. Nuclear Business Division (72) Inventor Nobuo Tada             3-1-1 Sachimachi, Hitachi City, Ibaraki Prefecture Stock Association             Hitachi, Ltd. Nuclear Business Division (72) Inventor Hideaki Sakai             2410 Motoe, Uozu City, Toyama Prefecture Sugi Co., Ltd.             Inside the machine F-term (reference) 2G075 AA03 BA17 CA07 DA15 FA13                       FC14 GA15

Claims (20)

[Claims] 1. An inspection / preventive maintenance device for an internal structure of a reactor pressure vessel for remote control access to an internal structure of a reactor pressure vessel filled with cooling water to inspect, clean and prevent the structure. The inspection / prevention / maintenance device has a fixing mechanism part for holding and fixing itself to the pressure vessel internal structure or the guide pipe, and a plurality of joint parts movably attached to the fixing mechanism part. An inspection / preventive maintenance device for the internal structure of a reactor pressure vessel, comprising a main body, the main body having a cavitation generator that utilizes cavitation collapse pressure. 2. An inspection / preventive maintenance device for an internal structure of a reactor pressure vessel for remote control access to an internal structure of the reactor pressure vessel filled with cooling water for inspection, cleaning and preventive maintenance of the structure. The inspection / prevention / maintenance device includes a fixing mechanism part for holding and fixing itself to the internal structure of the pressure vessel or the guide pipe, and a plurality of fixing mechanism parts movably and detachably attached to the fixing mechanism part. An inspection / preventive maintenance device for a structure inside a reactor pressure vessel, comprising a main body portion having a joint portion, the main body portion having a nozzle for ejecting high-pressure water to clean the structure and at the same time preventive maintenance. . 3. The body according to claim 1, wherein the main body portion is provided with a nozzle that generates cavitation bubbles, a CCD camera that monitors a construction portion, and an illumination unit. Inspection and preventive maintenance equipment for the structure inside the reactor pressure vessel. 4. The reactor according to any one of claims 1 to 3, wherein the main body portion includes an upper arm portion and a lower arm portion connected via a link, and the upper arm portion and the lower arm portion are respectively the reactor. An inspection / preventive maintenance device for a structure inside a reactor pressure vessel, which is provided with a connecting portion for connecting to a structure inside the pressure vessel. 5. The inspection / preventive maintenance device for the internal structure of a reactor pressure vessel according to claim 4, wherein the connecting portion includes an adsorption pad and a pad lifter for releasing adsorption of the adsorption pad. 6. The inspection / preventive maintenance device for an internal structure of a reactor pressure vessel according to claim 4, wherein the connecting portion comprises a holding portion for holding the internal structure of the reactor pressure vessel. 7. The inspection / preventive maintenance of the internal structure of a reactor pressure vessel according to claim 1, wherein the inspection / preventive maintenance device is capable of traveling in a guide pipe. apparatus. 8. The arm according to any one of claims 4 to 7, wherein the arm portion is provided with a nozzle for generating cavitation bubbles, a CCD camera for monitoring the construction portion, and a lighting device. Inspection and preventive maintenance equipment for the structure inside the reactor pressure vessel. 9. The inspection / prevention of an internal structure of a reactor pressure vessel according to claim 1, wherein the cavitation generator includes any one of a nozzle, an ultrasonic oscillator, and a laser oscillator. Security device. 10. A method of inspecting the reactor pressure vessel and internal structures inside the reactor pressure vessel in water while the reactor pressure vessel is filled with cooling water, comprising: A method for inspecting a reactor pressure vessel and reactor internals, characterized in that the surface of the reactor internals to be inspected is cleaned. 11. The method for inspecting a reactor pressure vessel and reactor internals according to claim 10, wherein the cleaning uses collapse pressure of cavitation bubbles. 12. The reactor pressure vessel and reactor internal structure according to any one of claims 10 to 11, wherein the cleaning utilizes collapse pressure of cavitation bubbles from high-pressure water. How to check. 13. The reactor pressure vessel and reactor internal structure according to any one of claims 10 to 11, wherein the cleaning uses collapse pressure of cavitation bubbles due to use of ultrasonic waves. How to check. 14. The inspection of reactor pressure vessel and reactor internal structure according to claim 10, wherein the cleaning uses collapse pressure of cavitation bubbles by using laser. Method. 15. The method for inspecting a reactor pressure vessel and reactor internals according to claim 10, wherein the cleaning is performed using high pressure water. 16. The method for inspecting a reactor pressure vessel and reactor internals according to claim 10, wherein the cleaning is performed using a flapper or a brush. 17. The inspection of a reactor pressure vessel and a reactor internal structure according to claim 10, wherein a compressive residual stress is applied to the cleaning surface by the cleaning. And preventive maintenance methods. 18. The method for inspecting a reactor pressure vessel and reactor internals according to claim 10, wherein the inspection is performed by an underwater camera. 19. Inspection of a reactor pressure vessel and reactor internals according to any one of claims 10 to 18, characterized in that the inspection device used comprises an underwater camera and cleaning means. apparatus. 20. The reactor pressure vessel and reactor internal structure according to any one of claims 10 to 18, characterized in that the inspection device used includes an ultrasonic flaw detector and cleaning means. Inspection device.