JP2007024857A - Work device and work method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a work device capable of moving to a large range within a short time with a small number of installations and supporting a large reaction force. <P>SOLUTION: The work device comprises a work apparatus 30 for applying work to a structure, expansion mechanisms 23 and 32 for moving the work apparatus 30 to a work position in the closed state, a conveyance mechanism (for example, horizontal thruster 26) for conveying the work apparatus and the expansion mechanisms to the work position, a pushing mechanism (for example, ballast tank 21) for pushing the work apparatus 30 to the lower surface of the structure, and a travel mechanism having wheels 24 that travel along the lower side face of the structure and position. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a work apparatus and a work method for performing work such as in a reactor lower part.

  In general, an in-reactor work device is used for in-core work such as inspection, inspection, and preventive maintenance of an inner wall of a reactor pressure vessel (RPV) and a structure inside the reactor. In particular, in the inspection of the weld line existing in the lower part of the shroud support plate at the lower part of the boiling water reactor (BWR), it is difficult to make the in-reactor work device reach this weld line. . In addition, since it is a narrow place, there is a problem that the work area is limited or the entire work time is increased. In order to secure a work range as wide as possible in a short period of time for these difficult-to-access parts, the following various in-reactor work apparatuses have been proposed.

  As a first example of a conventionally known in-reactor work apparatus, there is an apparatus provided with a remotely operated vehicle (ROV) in water, a forward / reverse / turning thruster, a lifting / traverse thruster, and an underwater television camera. Yes (see, for example, Patent Document 1). This device is provided with a rotatable arm mechanism, and various inspection means such as an ultrasonic inspection means, a radiation-resistant television camera, and an infrared camera are detachably attached to the tip of this mechanism.

  In this example, an XY scanner mechanism is disposed at the tip of the arm mechanism, and various inspection means are attached to this mechanism. As an example of inspection, the arm mechanism and various inspection means are transported to the inspection site by an underwater ROV thruster, the XY scanner is pressed near the inspection site, and the inspection means is scanned by the degree of freedom of operation to perform inspection. To do.

  Further, as a second example of a conventionally known in-reactor working apparatus, there is a vehicle type moving body as described below (for example, see Patent Document 2). In this apparatus, a plurality of wheeled arms (cylinder rods) are extended toward the RPV and the shroud support under the shroud support plate to temporarily fix the apparatus itself. Then, a thruster or a wheel provided on the moving body is driven to move to a work location along the circumferential direction, where the pressing pressure of the cylinder rod is increased and firmly fixed.

In this example, since the work reaction force from the work object is held by the wheel that is developed and pressed, a large work reaction force can be held. Further, by driving and moving the wheels, accurate positioning in the circumferential direction is possible, and position reproducibility can be ensured.
Japanese Patent Laid-Open No. 11-14784 JP 2001-296385 A

  With respect to the welding line under the shroud support plate at the bottom of the reactor in the above-described conventional reactor water, an inspection camera is mounted on the swimming vehicle and a VT inspection (Visual Testing) is performed, or the above-described swimming vehicle There is a device that mounts a UT probe in combination with an arm and performs UT inspection (Ultrasonic Testing).

  According to such an auxiliary mechanism such as a swimming vehicle and an arm, since it is excellent in portability and mobility, a wide range of inspections are possible in a short time, and an efficient operation is realized.

  However, preventive maintenance and welding work by brush polishing, water washing, water jet peening, and laser peening have a large work reaction force, and the work is difficult to carry, position, or hold by the above-described swimming mobile vehicle. Furthermore, there is a problem that accurate movement and positioning are difficult and it is difficult to ensure position reproducibility.

  On the other hand, the traveling wheel is developed toward the inner wall of the pressure vessel and the shroud support, and the position is fixed and the thruster or the wheel is driven to move horizontally. Positioning is considered possible.

  However, there is a concern that the vertical position is shifted when the vehicle is driven in the circumferential direction of the shroud or the RPV, and there is a problem that it is difficult to prevent or suppress the vertical position shift.

  The present invention has been made to solve the above problems, and can be moved over a wide range within a short time with a small number of installations, can support a large work reaction force, and can move accurately along a structure. Since positioning is performed, an object is to provide a working device and a working method capable of easily ensuring position reproducibility.

  In order to achieve the above object, a working device according to one aspect of the present invention is a mobile working device that performs work under a structure. When the working device performs the work and the working device is moved, An unfolding mechanism that can be closed and opened when performing work, a transport mechanism that transports the working device and the unfolding mechanism to a position for performing the work, a pressing mechanism that presses the working device against the structure, and a lower part of the structure And a travel mechanism including a wheel that travels and positions along the structure.

  According to another aspect of the present invention, there is provided a working device for working on a structure in water, a main body casing including a ballast tank, and an upper portion of the main body casing projecting outward through a drive mechanism. A working device that is freely provided and performs various operations on the structure, a float that is provided on the upper portion of the main body casing so as to be protruded outward via a drive mechanism, and an outer side of the working device and the float And a wheel for abutting against the structure and rotating the working device and the float.

  According to another aspect of the present invention, there is provided a work device method for carrying out work on a lower side of a structure, wherein the work device and the deployment mechanism are transported to a work position with the deployment mechanism closed. Opening the deployment mechanism after transporting the work equipment and the deployment mechanism to the working position and setting the work equipment to the lower side of the structure; pressing the set work equipment against the lower surface of the structure; The work equipment is positioned while being moved along the lower surface of the structure, and the work is performed on the structure by the traveled and positioned work equipment.

  According to another aspect of the present invention, there is provided a working device method in the working device method for performing work under a shroud support plate provided between a reactor pressure vessel and a shroud. An access hole cover attached to the access hole is removed, and after the cover removing step, the work equipment is transported to the lower side of the shroud support plate through the access hole and is transported after the transport step. It is characterized in that the work is performed in water for the lower part of the reactor in the reactor.

  According to the working device and the working method of the present invention, it can be moved over a wide range within a short time with a small number of installations, and a large working reaction force can be supported. And since it can move and position correctly along a structure, position reproducibility can be ensured easily.

  Embodiments of a working device and a working method according to the present invention will be described below with reference to the drawings. Here, the same or similar parts are denoted by common reference numerals, and redundant description is omitted.

[First Embodiment]
FIG. 1 is a schematic longitudinal sectional view showing an installation state of the in-reactor work device according to the first embodiment of the present invention.

  As shown in the figure, the reactor lower part, which is a work place in the reactor, includes an inner wall of a reactor pressure vessel (RPV) 2, a shroud support cylinder 5 on which a nuclear fuel assembly (not shown) is placed, The shroud support cylinder 5 is surrounded by a shroud support leg 6 and the like, and is formed from a narrow region located below the shroud support plate 7. The shroud support plate 7 is a horizontal plate that is provided between the shroud support cylinder 5 and the inner wall of the RPV 2.

  In the narrow area, there are a large number of weld lines. For example, an H8 horizontal weld line 9 that is a weld line that connects the shroud support cylinder 5 and the shroud support plate 7, an H9 horizontal weld line 10 that is a weld line that welds the RPV 2 and the shroud support plate 7, and an H10 weld line 11, There are H11 welding line 12, AD-2 welding line 13, and the like.

  When performing various operations such as inspection, polishing, water washing, preventive maintenance, and repairing on these many welding lines 9 to 13, the inside of the RPV 2 is filled with water, and the in-reactor working device 20 is installed in the water. The A cable (not shown) is connected to the in-reactor working device 20, and the other end of the cable is connected to the control unit of the control device installed on the operating floor or the fuel changer existing above the RPV 2, and Connected to the operation unit.

  Here, the in-reactor work device 20 will be described. 2 is a front view showing the configuration of the in-reactor working device 20 of FIG. 1, and FIG. 3 is a top view showing the configuration of the in-reactor working device 20 of FIG. FIG. 4 is a front view showing the configuration of the wheel deployment mechanism 32 of FIG.

  As shown in the figure, the in-reactor working device 20 includes a cylindrical main body casing 22 in which a ballast tank 21 is incorporated. On the upper part of the main body casing 22, wheel unfolding mechanisms 23 and 32 for unfolding the work equipment 30 or the traveling wheel 24 are mounted.

  At least three types of traveling wheels 24 to be deployed are installed. A work device 30 is disposed between the pair of traveling wheels 24. Ball casters 25 are respectively attached to the upper portions of the three traveling wheels 24. An origin detection sensor 31 for setting the origin position is attached to the upper part of the in-reactor work device 20. Two upper and lower thrusters 28 (only one is shown in the figure) are attached to the lower part of the main casing 22 and are driven by a drive motor 27. Two horizontal thrusters 26 (only one is shown in the figure) are also attached to the central portion of the main casing 22 and are driven by a drive motor (not shown).

  The main body casing 22 is formed in a cylindrical shape having a dimension capable of passing through a round hole (not shown) of the core support plate 3. The overall height of the in-reactor working device 20 is also dimensioned so that it can pass through the shroud support legs 6 and enter the shroud support plate 7 after passing through the round hole of the core support plate 3 and entering the lower part of the reactor. Is formed.

  Further, the plurality of floats 29a and 29b arranged on the upper part of the in-reactor working device 20 are configured such that the center of gravity of the entire working device is lower than the buoyancy even when all the air is injected into the ballast tank 21. It is balanced so that the work equipment 30 is always upward.

  As shown in FIG. 3, the in-reactor work device 20 is provided with at least three types of wheel deployment mechanisms 23 and 32. In the example shown in the figure, there is one set of the wheel deployment mechanism 23, and two floats 29a, one wheel 24, and one ball caster 25 are attached. Two types of wheel deployment mechanisms 32 form a pair, and a single float 29b is supported by being sandwiched between these wheel deployment mechanisms 32. Each wheel deployment mechanism 32 has one wheel 24 and a ball caster at the tip. 25 is attached. In the wheel deployment mechanisms 23 and 32, the traveling wheel 24 is rotationally driven by a wheel drive motor 40 that is directly connected coaxially with the rotation shaft.

  Below the wheel drive motor 40, a roller 46 for measuring a travel distance along the outer surface of the shroud and a rotation sensor 45 directly connected thereto are attached. The traveling wheel 24, the roller 46, and the rotation sensor 45 are connected to the main body casing 22 side by a parallel link 42, and are stored by the air cylinder 41 while keeping the wheel rotation shaft vertical. Both ends of the parallel link 42 are rotatably supported by the bracket 60 and the pin 61.

  As described above, the in-reactor work device 20 is moved to the lower side of the shroud support plate 7 with the wheel deployment mechanisms 23 and 32 stored in a vertical state. After that, by supplying air to the air cylinder 41, the traveling wheel 24, the roller 46, and the rotation sensor 45 are pressed against the inner wall of the shroud support cylinder 5 and the RPV 2 to generate a horizontal traveling driving force, and the outer peripheral surface of the shroud Can move along. At the same time, the relative distance moved along the outer peripheral surface of the shroud can be measured by the pressed roller 46 and the rotation sensor 45.

  In the example shown in the figure, the driving air cylinder 41 is arranged at the upper part of the main body casing 22. However, as a modification, the driving source of the wheel deployment mechanisms 23 and 32 is arranged at the lower part of the ballast tank 21. It is also conceivable to construct a link that can be deployed by this drive source. In this case, the center of gravity of the apparatus can be further lowered, so that the posture in water can be further stabilized.

  Here, handling of the in-reactor work apparatus 20 will be described. FIG. 5 is a front view showing an operation state of the in-reactor working device 20 according to the embodiment of the present invention, and FIG. 6 is a top view showing an operation state of the in-reactor working device 20 according to the embodiment of the present invention. It is.

  For example, various operations are performed on the H8 horizontal welding line 9 which is a welding line below the shroud support plate 7 shown in FIG.

  The in-reactor working device 20 is suspended from above the RPV 2 into the RPV 2 filled with water by a cable (not shown), passes through the upper lattice plate and the core support plate 3 and moves to a narrow area at the lower part of the reactor. Is done. At this time, air in the ballast tank 21 is discharged and water is injected to reduce buoyancy and generate sedimentation force. At the same time, the submarine is submerged together with the settling thrust by the vertical thruster 28. Then, it passes between the shroud support legs 6 and enters under the shroud support plate 7.

  When this in-reactor working device 20 is entered, air is injected into the ballast tank 21 or the internal water is discharged, and the entire underwater weight of the device is adjusted to approximately 0 kgf, and is moved horizontally by the horizontal thruster 26. To do. Then, the work device 30 rotates around the vertical axis so as to face the shroud support cylinder 5 and is aligned.

  Next, the traveling wheel 24 is unfolded and installed until just before the traveling wheel 24 contacts the outer surface of the shroud support cylinder 5. Then, by injecting air into the ballast tank 21 and discharging the internal water, the in-reactor working device 20 is lifted and the three ball casters 25 are brought into contact with the lower surface of the shroud support plate 7.

  As described above, after the position in the vertical direction of the in-reactor working device 20 is determined, the deployment force is further increased and the traveling wheel 24 is firmly pressed against the shroud support cylinder 5 and the inner wall of the RPV 2. During traveling, the traveling wheels 24 are driven to travel while the ball caster 25 is always in contact with the lower surface of the shroud support cylinder 7 due to the buoyancy generated by the ballast tank 21. As a result, the in-reactor working device 20 can be moved horizontally along the H8 weld line 9.

  In addition, the reference position in the circumferential direction with respect to the H8 horizontal welding line 9, that is, the origin of travel, is a round hole of the shroud support plate 7 to which the jet pump adapter 8 is fixed by an origin detection sensor 31 such as an ultrasonic distance sensor. The reference position is set by detecting the inner edge of the bottom from the lower side.

  Then, the roller 46 is brought into contact with the wall surface, the movement distance is directly measured by the rotation sensor 45, and the relative movement distance from the origin position is calculated. Further, the work is performed by various work devices 30 while the relative position and posture with respect to the work target are adjusted remotely by the scan mechanism. For example, in the case of visual inspection, a CCD camera is mounted as the work device 30, and a pan head is mounted as the scanning mechanism. While moving in the horizontal direction, the vicinity of the weld line is imaged continuously, and the pan head is adjusted so that a desired imaging area is obtained, and inspection is performed while changing the direction of the camera.

  Other ultrasonic flaw detection sensors and eddy current flaw detection sensors can be similarly operated by being mounted together with a scanning mechanism configured with a required degree of freedom.

  In the same manner as the above procedure, various operations can be performed on the H9 horizontal welding line 10 as long as the work device 30 enters and expands so as to face the inner wall side of the RPV 2.

  According to the present embodiment, when performing various operations on the reactor internal structure in the reactor pressure vessel in the reactor water, the weld line under the shroud support plate 7 is particularly difficult to access. Repair work such as preventive maintenance and welding by inspection, polishing, water washing, water jet peening or laser peening becomes possible.

Moreover, since it can move to a wide range with a small number of times of insertion (number of installations), efficient work becomes possible.

  Moreover, since the traveling wheel 24 is unfolded and pressed, a large reaction force can be supported and stable work can be performed.

  Further, since the traveling wheel 24 continuously travels with respect to the outer surface of the shroud support cylinder 5, accurate and continuous positioning is realized, position reproducibility is easily ensured, and work quality can be improved. Moreover, since it can move along the lower surface of the shroud support plate 7 by buoyancy, the vertical position of the in-reactor work device is guaranteed and work quality can be improved.

  The work equipment 30 is selected from a brush for polishing work, a polishing jig, a nozzle for water cleaning, a water jet peening head for preventive maintenance, a laser peening head, or a welding head for repair.

  With these various work devices 30, it is possible to perform a stress improvement process or a repair work as a polishing work, a cleaning work, or preventive maintenance.

  Therefore, it is possible to perform not only inspection but also polishing work, cleaning work, stress improvement processing or repair work as preventive maintenance on a weld line in a narrow area under the shroud support plate which is difficult to access.

  In the present embodiment, the transport mechanism of the in-reactor working device is realized by adjusting the buoyancy of the two horizontal thrusters 26 and the ballast tank 21.

  It moves up and down by the ascending or sinking force generated by the ballast tank 21, and moves horizontally and rotates around the vertical axis by the thrust of the horizontal thruster.

According to the present embodiment, the degree of freedom in driving is reduced and the number of cables can be reduced, so that the handling property can be further improved. In addition, with a simpler structure, the in-reactor working device 20 can be submerged, levitated, or pressed to the lower surface of the shroud support plate.
In the present embodiment, the traveling wheel 24 is preferably a truncated cone-shaped rubber wheel. Since the large-diameter side is attached so as to be on the lower side, it is possible to apply a force in the direction of shifting the apparatus upward by rotating by pressing horizontally against the wall surface.

  Accordingly, it is possible to push the device to the lower surface of the shroud support plate more firmly together with the buoyancy due to the ballast tank, so that it is possible to move horizontally along the shroud support plate with certainty.

[Second Embodiment]
FIG. 7 is a diagram showing a fifth embodiment of the present invention. Here, the same or similar parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this embodiment, as compared with the first embodiment shown in FIG. 2, the drive mechanism 32 that supports and drives the work equipment 30 and the float 29b includes two links that are adjacent in the horizontal direction. Is different. Others are the same as those in the first embodiment.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS. Here, the same or similar parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 8 and 9, the pressure vessel 2 is provided with an upper lattice plate 43 having an opening and a core support plate 3 having an opening. The in-reactor working device 20 passes through the opening 44 of the upper lattice plate 43 and the opening of the core support plate 3 to access the lower part of the shroud support plate 7 from the inner surface of the shroud 100 and the access hole 46a. The shroud 1 is guided to the lower part of the shroud support plate 7 by two kinds of routes 44 and 145 of the route 145 that access the lower part of the shroud support plate 7 from the outer surface.

  According to the present embodiment, when various operations are performed on the reactor internal structure in the pressure vessel 2 in the reactor water, the shroud support cylinder 5 and the shroud support can be applied to any environment in the reactor. H8 horizontal weld line 9 which is a weld line of the plate 7, H9 horizontal weld line 10 which is a weld line of the pressure vessel 2 and the shroud support plate 7, and H10 weld line 11 which is a weld line of the shroud support leg 6 and the shroud support cylinder 5. Various operations can be performed on the H11 weld 12 that is the weld line between the shroud support leg 6 and the pressure vessel 2 and the AD-2 weld line 13 that is the weld line between the jet pump 8 and the shroud support plate 7. is there.

  That is, for example, even when the control rod guide tube 141 and the fuel are all installed and it is impossible to adopt the access route 44 to the lower part of the shroud support plate 7, the access hole cover 146 is removed for access. Route 145 can be employed.

  As shown in FIGS. 10 and 11, the access hole 46 a provided in the pressure vessel 2 is covered with an access hole cover 146. The access hole cover 146 is fixed to the access hole peripheral edge 46 b by six bolts (fastening portions) 50, and a retainer 52 is interposed between the access hole cover 146 and the nut 51.

  Further, a nut 51 is engaged with each bolt 50, and a stopper 53 that contributes to stopping the rotation of the bolt 50 comprises a spring mechanism. For this reason, attachment and removal of the bolt 50 can be easily performed.

  That is, since the stopper 53 of the bolt 50 is constituted by the spring mechanism 53, the access hole cover 146 can be easily attached and detached by using a handling jig dedicated to the locking key. With such a configuration, even when fuel (not shown), a control rod guide tube 141 and the like are loaded in the furnace, the access hole cover 146 can be removed to easily inspect the lower portion of the shroud support plate 7. Repair work such as polishing, water washing, preventive maintenance by water jet peening or laser peening, welding, etc. becomes possible.

[Fourth Embodiment]
Next, an in-reactor work device according to a fourth embodiment of the present invention will be described. In the embodiment of the present invention, a polymer resin material is used for the mechanism constituent member and the strength holding member of the in-reactor work apparatus and various work devices in each of the above-described embodiments.

  Specific materials include polyamide resin, polyimide resin, polyether ether ketone resin, and polyether sulfone resin, which have good radiation resistance, water absorption, mechanical strength, and heat resistance. Part or all of them are applied as the above-described mechanism constituent member and strength holding member.

  According to the present embodiment, the metal member can be replaced with a polymer resin material, and the underwater weight of the in-reactor work device and various work devices can be reduced. As a result, the ballast tank can be made smaller, and the overall dimensions can be reduced. Since weight reduction and size reduction are realized, the handling reliability is improved and the narrow portion is easily moved, so that the work reliability can be improved.

  Furthermore, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  For example, the inspection result may be displayed on a display device.

  In the above embodiment, the in-reactor work apparatus and the work method for performing work in the reactor have been described. However, the present invention is more generally applicable as a work apparatus and a work method. .

  In addition, in the above-described embodiment, a working apparatus and a working method that mainly perform work in water have been described, but the following modifications are also conceivable. That is, although the adsorption traveling module 22 constituting the operation mechanism and the accompanying mechanism are surrounded by a case-like one in which the inside is kept watertight and performs an adsorption traveling operation in water, an actual work device is the operation mechanism. A working device and a working method for working in the air in the air can be considered. In addition, for example, by increasing the shape of the thruster 41 of the adsorption travel module 22 and increasing the scale of the thruster drive source and drive mechanism, the airflow sufficient to exert the adsorption force in the air by the high-speed rotation of the thruster 41 is obtained. By adopting a configuration that can be obtained, the present invention can also be applied as a working device and a working method that perform work in the air.

The schematic longitudinal cross-sectional view which shows the installation state of the in-reactor work apparatus of the 1st Embodiment of this invention. FIG. 2 is a front view showing the configuration of the in-reactor work device of FIG. 1. The top view which shows the structure of the work apparatus in the reactor of FIG. The front view which shows the structure of the wheel expansion | deployment mechanism of FIG. The front view which shows the operation state of the in-reactor work apparatus of the 1st Embodiment of this invention. The top view which shows the operation state of the reactor internal reactor of the 1st Embodiment of this invention. The front view which shows the structure of the reactor internal reactor of the 2nd Embodiment of this invention. The longitudinal cross-sectional view which shows notionally the access route to the shroud support plate lower part in the nuclear reactor in the 3rd Embodiment of this invention. The horizontal sectional view which shows notionally the position of the access hole cover and access hole cover in the 3rd Embodiment of this invention. The top view which shows the access hole cover in the 3rd Embodiment of this invention. The elevation view which shows the vicinity of the volt | bolt which fixes the access hole cover in the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Shroud middle part copper, 2 ... Reactor pressure vessel (RPV), 3 ... Reactor core support plate 4 ... Shroud lower shell, 5 ... Shroud support cylinder, 6 ... Shroud support leg, 7 ... Shroud support plate, 8 ... Jet pump Adapter, 9 ... H8 horizontal weld line, 10 ... H9 horizontal weld line, 11 ... H10 weld line, 12 ... H11 weld line, 13 ... AD-2 weld line, 20 ... In-reactor work device (underwater work device), 21 DESCRIPTION OF SYMBOLS ... Ballast tank, 22 ... Main body casing, 23 ... Wheel deployment mechanism, 24 ... Traveling wheel, 25 ... Ball caster, 26 ... Horizontal thruster, 27 ... Drive motor, 28 ... Vertical thruster, 29a ... Float, 29b ... Float, 30 ... Work equipment 31 ... Origin detection sensor 32 ... Drive mechanism 40 ... Wheel drive motor 41 ... Air cylinder 42 ... Parallel link 4 ... upper lattice plate, 44 ... access route to shroud support plate lower part, 45 ... rotation sensor, 46 ... roller, 46a ... access hole, 50 ... bolt, 51 ... nut, 52 ... retainer, 53 ... stopper, 60 ... bracket, 61 ... Pin, 100 ... Shroud, 141 ... Control rod guide tube, 145 ... Access route to lower part of shroud support plate, 146 ... Access hole cover

Claims (16)

In a mobile work device that works under the structure,
A working device for performing the work;
A deployment mechanism that can be closed when moving the work equipment and open when performing work;
A transport mechanism for transporting the work device and the deployment mechanism to a position for performing the work;
A pressing mechanism that presses the work device against the structure;
A traveling mechanism including wheels for traveling and positioning the lower side of the structure along the structure;
A working apparatus comprising:   2. The work apparatus according to claim 1, wherein the structure is an annular shroud support plate disposed substantially horizontally between an inner surface of the reactor pressure vessel and an outer surface of the shroud.   The working apparatus according to claim 1, wherein the transport mechanism includes a ballast tank that submerses and levitates the working equipment in water. In work equipment that works on structures underwater,
A body casing including a ballast tank;
Work equipment provided on the upper part of the main body casing so as to be able to protrude outwards via a drive mechanism, and for performing various operations on the structure;
A float provided on the upper part of the main body casing so as to protrude outwards via a drive mechanism;
Wheels that are provided on the outer side of the work equipment and the float, contact the structure, and rotate the work equipment and the float;
A working apparatus comprising:   The structure is an annular shroud support plate disposed substantially horizontally in a space between the inner surface of the reactor pressure vessel and the outer surface of the shroud, and a structure in a space below the shroud support plate. The working device according to claim 4.   6. The work device according to claim 1, wherein the work device is at least one selected from an inspection sensor, a visual inspection camera, an ultrasonic flaw detection sensor, and an eddy current flaw detection sensor. Work equipment.   The work equipment was selected from a brush for polishing work, a polishing jig, a nozzle for water washing, a water jet peening head, a laser peening head, a welding head for repair welding, and a grinding jig for grinding a welded portion. The working device according to claim 1, wherein the working device is at least one.   The work according to any one of claims 1 to 7, wherein the transport mechanism includes a thruster capable of moving the work device up and down, moving horizontally, and rotating around a vertical axis. apparatus.   The working device according to any one of claims 1 to 8, wherein the traveling mechanism includes at least three wheels and a deployment mechanism that deploys and presses the wheels.   10. The wheel according to claim 1, wherein the wheel has a truncated cone shape attached so that a large-diameter side is on a lower side, and exerts a force to move upward by rotating while pressing against a wall surface. The working device according to any one of the above.   The working device according to any one of claims 1 to 10, further comprising a mechanism constituent member or a strength holding member using a polymer resin material. In the work method of working under the structure,
Transport the work equipment and the deployment mechanism to the work position with the deployment mechanism closed,
After opening the unfolding mechanism after transporting the working device and the unfolding mechanism to the working position, the working device is set below the structure;
Press the set work equipment against the lower surface of the structure,
Positioning the work equipment along the lower surface of the structure,
The work is performed with respect to the structure by the working equipment positioned by running.
A working method characterized by that.   The working method according to claim 12, wherein the structure is an annular shroud support plate disposed substantially horizontally between an inner surface of the reactor pressure vessel and an outer surface of the shroud. In the working method of working under the shroud support plate provided between the reactor pressure vessel and the shroud,
Remove the access hole cover attached to the access hole provided in the shroud support plate,
After the cover removing step, transport work equipment through the access hole to the underside of the shroud support plate;
Work in water against the lower part of the reactor in the reactor using work equipment transferred after the transfer step,
A working method characterized by that.   15. The working device is at least one selected from an inspection sensor, a visual inspection camera, an ultrasonic flaw detection sensor, and an eddy current flaw detection sensor. Work equipment method.   The work equipment was selected from a brush for polishing work, a polishing jig, a nozzle for water washing, a water jet peening head, a laser peening head, a welding head for repair welding, and a grinding jig for grinding a welded portion. The work device method according to claim 12, wherein the work device method is at least one.

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