JP2013129031A - Underwater drilling apparatus and underwater reracking method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underwater drilling apparatus capable of smoothly performing drilling operation under water while the apparatus is reliably positioned and fixed, with simple operation and structure.SOLUTION: The underwater drilling apparatus includes: a tool body 10 which is suspended from a temporary crane 103 and is positioned with respect to and fixed to a support plate 112 of an existing spent fuel storage rack 111, by means of a clamp mechanism 11; a cutter driving device 12 assembled on the tool body 10; a control panel 14 controlling the cutter driving device from an operation floor 126; and a waste water treatment device 15 sucking and collecting cutting chips from the operation floor. The cutter driving device has: a movable housing 24 in which a cutter rotating shaft 22 with a trepanning cutter 21 mounted thereto and a cutter rotating motor 23 are housed; and a fixed housing 28 in which the movable housing is vertically movably supported and a cutter feed shaft 26 providing feed to the trepanning cutter and a cutter feed motor 27 are housed, wherein the trepanning cutter includes a pit water inflow hole 29 for recovering cutting chip.

Description

  The present invention relates to an underwater drilling device that is effective when applied to, for example, a nuclear power generation facility (plant) and an underwater reracing method using the device.

  Spent fuel used for nuclear power generation is stored in a spent fuel storage rack installed on the floor of the spent fuel storage pit (pool) established in the nuclear power generation facility, where it is cooled for a certain period. Then, it is carried out to a reprocessing facility outside the facility.

  In recent years, as the amount of power generated by nuclear power generation has increased, the amount of spent fuel has increased, and the need to enhance the storage capacity of spent fuel within the nuclear power plant has increased. The enhancement of the storage capacity of the spent fuel is carried out by performing so-called relacking in which the rack cells containing the spent fuel are rearranged more closely.

  Examples of the reracing method include those disclosed in Patent Document 1 and Patent Document 2. First, the existing spent fuel storage rack composed of a plurality of rack cells is removed from the foundation bolts embedded in the floor of the spent fuel storage pit, and then the existing spent fuel storage rack is lifted and removed. To do. Then, after installing the gantry block at the position where the existing spent fuel storage rack has been removed, the spent spent on the cradle block with the density of rack cells set higher than that of the existing spent fuel storage rack by stud bolts. A fuel storage rack will be installed.

  In addition, as disclosed in Patent Document 3, in the modification of the spent fuel rack, a reinforcing plate having a securing plate is attached to the outer periphery of the replacement spent fuel rack body, and the securing plate and The fixing plate, the connecting plate, the connecting plate, and the support of the old rack are interposed between the support plate of the old rack that has been cut off and left behind and the screw for fixing the bolt is interposed. In some cases, the replacement spent fuel rack is firmly fixed to the side wall surface of the spent fuel storage pit by fixing the plates with bolts.

JP 2003-270281 A JP-A-4-285895 JP 2003-307586 A Japanese Patent No. 4154463

  However, in the reracing method disclosed in Patent Document 1 and Patent Document 2, there is no clear indication that the relacing method is performed in water, and the nut is removed or attached with an elongated fastening tool without drilling a bolt hole. This makes it possible to replace the existing rack and the new rack on the floor of the spent fuel storage pit. A specific configuration is not disclosed.

  Further, in the reracing method disclosed in Patent Document 3, when drilling the support plate of the old rack left on the side wall surface of the spent fuel storage pit, “underwater and remote operation is performed. Since the specific configuration of the dedicated jig is not disclosed, it is unclear whether or not it can be implemented.

  Patent Document 4 discloses a method and a tool for drilling a hole in a core shroud support plate in a nuclear reactor vessel by remote operation in water. This means that the drilling tool is fixed to the support base and drills a hole that penetrates approximately 90% of the shroud support plate. The drilling tool has a chip collection structure and is made up of atoms generated by the chip generated in the machining process. Prevents contamination of water in the furnace vessel After forming approximately 90% of the holes with a drilling tool, an EDM tool is fixed to the support base and the remainder of the hole is machined by EDM. Has a structure for machining the remainder of the hole, and after removing the slag from the hole, it sits under the shroud support plate. "

  However, in the underwater remote drilling tool and method disclosed in Patent Document 4, at least the drilling tool and the support base are divided, and it is necessary to position and fix the core shroud support plate to each other by remote control. In addition, the operation is complicated and each positioning and fixing structure is complicated, so that there is a problem that it cannot be applied to the reracing method.

  Therefore, the present invention provides an underwater drilling device capable of smoothly drilling in water while securely positioning and fixing the device with a simple operation and structure, and a used device in a high-dose environment using the device. An object of the present invention is to provide an underwater reracing method capable of safely underwater reracing work in a fuel storage pit.

An underwater drilling device according to the present invention for achieving such an object,
An underwater drilling device that drills holes in the structure in the pit.
A tool body suspended from the ground and positioned and fixed to the structure by a clamp mechanism;
A cutter driving device assembled on the tool body;
A control panel for controlling the cutter driving device from the ground using an operation unit as appropriate;
Wastewater treatment equipment for sucking and collecting cutting chips generated by the cutter driving device from the ground using pit water,
With
The cutter driving device includes a movable housing in which a cutter rotating shaft for mounting a trepanning cutter that cuts the structure into a ring shape by rotation to form a hole and a cutter rotating motor that rotates the cutter rotating shaft are accommodated. A cutter feed shaft that supports the movable housing so as to be movable in the axial direction of the cutter rotating shaft, and applies feed to the trepanning cutter via the movable housing; and a cutter feed motor that rotates the cutter feed shaft. The trepanning cutter is provided with a pit water inflow hole for collecting cutting chips together with the pit water by a swirling vortex by rotation,
It is characterized by that.

Also,
A chip breaker mechanism for providing a function of a chip breaker to the trepanning cutter is interposed between the cutter rotating shaft and the movable housing.

Also,
A piston rod that pushes out a cutting lump (core) from the trepanning cutter is housed inside the cutter rotating shaft so as to be movable in the axial direction of the cutter rotating shaft.

Also,
The cutter driving device is slidably supported on a tool body via a slide base, and can drill holes in at least two places of the structure.

Also,
The waste water treatment facility is characterized in that after cutting chips collected by suction with a pump are purified with filters, the filtered water is returned to the pits.

Also,
Furthermore, the cutting lump collection tool for collecting the cutting lump pushed out from the trepanning cutter is provided so as to be remotely operable from the ground.

  The tool body is a so-called long type in which a cutter rotation shaft and a cutter rotation motor, and a cutter feed shaft and a cutter feed motor of the cutter driving device are directly connected to each other in the vertical direction.

  The tool main body is a so-called short type in which a cutter rotation shaft, a cutter rotation motor, a cutter feed shaft, and a cutter feed motor of the cutter driving device are horizontally arranged via gear mechanisms.

An underwater reracing method according to the present invention for achieving such an object,
After the existing spent fuel storage rack composed of a plurality of rack cells installed in the spent fuel storage pit is lifted and removed by cutting the support plate provided on the outer periphery thereof, the density of the rack cells becomes the existing spent fuel storage rack. When installing a new spent fuel storage rack that is set higher than that of the existing spent fuel storage rack, a support plate provided on the outer periphery of the new used fuel storage rack and the existing use left in the spent fuel storage pit In underwater reracking work that bolts the support plate part of the spent fuel storage rack through the connecting plate,
Prior to cutting the support plate of the existing spent fuel storage rack,
After suspending the tool body of the underwater drilling device and positioning and fixing to the support plate of the existing spent fuel storage rack by the clamp mechanism,
After operating the cutter driving device to make one or more holes in a predetermined position of the support plate,
The support plate is cut leaving the support plate portion subjected to the drilling process,
It is characterized by that.

When hanging the tool body of the underwater drilling device, the address plate of the rack cell installed on the existing spent fuel storage rack is bent in advance.
It is characterized by that.

  According to the underwater drilling apparatus according to the present invention, the cutting is performed by the trepanning cutter in a state where the tool body is suspended from the ground and positioned and fixed to the structure in the pit by the clamp mechanism integrated with the tool body. Since the chip is sucked and collected from the ground using pit water, the cutter drive device is operated remotely from the ground control panel to drill holes in the structure, so the device can be operated with simple operation and structure. Drilling can be performed smoothly in water while reliably positioning and fixing.

  According to the underwater reracing method according to the present invention, the existing used fuel is mounted by the cutter driving device on the tool body that is securely positioned and fixed by the clamp mechanism to the support plate of the existing used fuel storage rack using the underwater drilling device. Since the support plate of the fuel storage rack can be drilled smoothly by remote control, underwater reracing can be safely performed in the spent fuel storage pit in a high-dose environment.

It is a schematic structure perspective view of the underwater drilling apparatus which shows one Example of this invention. It is sectional drawing of the clamp mechanism of a tool main body. It is explanatory drawing of the pit water inflow hole for cutting chip collection | recovery. It is explanatory drawing of the piston rod for core collection | recovery. It is an installation state figure of a cutter drive device. It is a cutting completion state figure of a cutter drive device. It is a core extrusion state figure of a cutter drive device. It is an initial state figure of the slide mechanism in a cutter drive device. It is a state figure after the slide of the slide mechanism in a cutter drive device. It is an installation procedure figure of a core recovery tool. It is a perspective view which shows the modification of a tool main body. It is a connection structure figure of the existing spent fuel storage rack and support board in re-racking construction. It is a joint structure figure of the new support structure and support board in re-racking construction. It is process drawing of the whole reracking construction. It is process drawing of the whole reracking construction.

  Hereinafter, an underwater drilling apparatus according to the present invention and an underwater reracing method using the apparatus will be described in detail with reference to the drawings.

  1 is a schematic configuration perspective view of an underwater drilling device showing an embodiment of the present invention, FIG. 2 is a sectional view of a clamping mechanism of a tool body, FIG. 3A is an explanatory view of a pit water inflow hole for cutting chip collection, 3B is an explanatory diagram of a piston rod for core recovery, FIG. 4A is an installation state diagram of the cutter driving device, FIG. 4B is a cutting completion state diagram of the cutter driving device, FIG. 4C is a core extrusion state diagram of the cutter driving device, FIG. Is a state diagram before sliding of the slide mechanism in the cutter driving device, FIG. 5B is a state diagram after sliding of the sliding mechanism in the cutter driving device, FIG. 6 is a diagram showing how to install the core recovery tool, and FIG. FIG. 8 is a structural view of the existing spent fuel storage rack and the support plate in the re-racking work. FIG. 9 is a structural view of the new support structure and the support plate in the re-racking work. 10 process diagram Rirakkingu construction in general, Fig. 11 is a process diagram of a Rirakkingu construction in general.

  The present embodiment is an example in which the underwater drilling device of the present invention is used for reracking work in a nuclear power generation facility (plant). Therefore, the overall steps of reracking work will be described with reference to FIGS.

  First, in Step 1, the temporary crane 103 is installed on the existing rail 102 that is laid on both sides of the spent fuel storage pits (pools) 100A and 100B arranged side by side and on which the spent fuel storage pit crane 101 travels. The temporary crane 103 is a larger frame than the spent fuel storage pit crane 101, and includes four wire jacks 104, a rack cradle 105, and the like.

  In the figure, reference numeral 106 denotes a fuel inspection pit for inspecting the fuel assembly and its handling tool, and 107 denotes an existing spent fuel storage rack assembly 109 (process) lifted and removed from the spent fuel storage pit (pool) 100A or 100B. Decontamination site pit for decontamination and shredding. Reference numeral 108 in the figure denotes a temporary floor on which a new support structure 116 (see step 5) as a new spent fuel storage rack is temporarily placed. The existing spent fuel storage rack assembly 109 is a structure in which a large number (for example, 150) of rack cells 110 are installed on the existing spent fuel storage rack 111 (see step 2), and a number of new support structures 116 are present. This refers to a frame on which (for example, 300) rack cells 121 can be installed (see step 6).

  Next, in step 2, for example, in the spent fuel storage pit 100A, all the fuel assemblies in the existing spent fuel storage rack assembly 109 to be lifted and removed are used by the spent fuel storage pit crane 101 to make other unused existing spent spent. After temporarily moving and storing in the fuel storage rack assembly 109, the temporary crane 103 is moved directly above the existing spent fuel storage rack assembly 109 to be lifted and removed. Then, after the tool body 10 (see FIG. 1) in the underwater drilling apparatus of the present invention is incorporated into the auxiliary hoist 120 of the temporary crane 103 via the manipulator or the telescopic pole 113, the tool body 10 (see FIG. 1) is suspended, and Bolt holes for attaching a required number of connecting plates are drilled in a support plate (structure) 112 provided on the outer periphery of two existing spent fuel storage racks 111 and connected and fixed to the side wall surface of the spent fuel storage pit 100A.

  Next, in step 3, the auxiliary hoist 120 of the temporary crane 103 is assembled with the tool main body 114 of the underwater electrical discharge machining cutting device via the manipulator or the telescopic pole 113 instead of the tool main body 10 of the underwater drilling device, The support plate 112 provided on the outer periphery of the lower two existing spent fuel storage racks 111 is left using a local seal box or the like so as to leave the support plate portion (pit side wall side) 112a having a bolt hole. Disconnect.

  Next, in step 4, after setting the existing spent fuel storage rack hanging device 115 from the temporary crane 103 on the existing spent fuel storage rack assembly 109 to be lifted and removed, the wire jack 104 is operated to operate the existing spent fuel. The storage rack assembly 109 is lifted and transferred to the rack cradle 105. Then, the temporary crane 103 is run to suspend the existing spent fuel storage rack assembly 109 from the decontamination site pit 107 to decontaminate the existing spent fuel storage rack assembly 109, and chopped and discarded.

  Next, in step 5, after the new support structure 116 stored on the temporary floor 108 is taken into the temporary crane 103, the new support structure hanging tool 117 is set on the new support structure 116. Then, the wire jack 104 is operated to suspend the new support structure 116 at the position where the existing spent fuel storage rack assembly 109 is lifted and removed. The provided support plate 118 is connected to the remaining support plate portion 112a of the above-described existing spent fuel storage rack assembly 109 by bolts and nuts via a connection plate (not shown) (see connection plate 119 in FIG. 9). Thereby, the new support structure 116 is fixed to the side wall surface of the spent fuel storage pit 100A.

  Finally, in step 6, by inserting a number of new rack cells 121 from the temporary crane 103 using the auxiliary hoist 120 or the like into the lattice of the new support structure 116 and installing them, a predetermined inspection is performed. The re-racking work is finished. After that, the fuel assemblies temporarily moved and stored in the other existing spent fuel storage rack assembly 109 by the spent fuel storage pit crane 101 are respectively stored in the rack cells 121 of the new support structure 116. It is housed.

  Further, as shown in FIG. 8, the support plate 112 of the above-described existing spent fuel storage rack 111 is formed integrally with the existing spent fuel storage rack 111 by arranging a large number of square holes 122 and its outer edge. The portion is connected and fixed to a support fitting 123 welded to an embedding plate installed on the side wall surface of the spent fuel storage pit 100A.

  Then, before the tool body 10 of the underwater drilling device is suspended and the bolt hole 124 for attaching the connecting plate is opened in the support plate 112, the tool body 10 is attached to the rack cell 110 in order to smoothly suspend it. In order to make the address plate 125 hang down from the horizontal state, the address plate 125 is bent using an underwater plate bending apparatus.

  Further, after the bolt holes 124 are opened in two places in the vertical direction on the support plate 112 of the existing spent fuel storage rack 111, the tool main body 114 (see step 3 in FIG. 10) of the underwater electric discharge machining apparatus is used. Then, the portion of the support plate 112 indicated by the broken line in the drawing is cut, and the existing spent fuel storage rack assembly 109 is lifted and removed.

  On the other hand, as shown in FIG. 9, the support plate 118 of the new support structure 116 is formed separately from the new support structure 116, and the support plate 112 of the existing spent fuel storage rack 111 described above (to be exact, The support plate portion 112a) is attached at a position corresponding to the support plate portion 112a). The support plate 118 is previously formed with bolt holes 126 for attaching the connecting plate in the air at two locations in the lateral direction.

  Then, after the new support structure 116 is suspended and installed in the spent fuel storage pit 100A, the bolt hole of the support plate portion 112a that is left on the basis of the bolt hole 126 of the support plate 118 using the underwater hole position measuring device. The position of 124 is measured. In other words, the bolt hole can be formed in the connecting plate 119 in the air at an accurate position corresponding to the bolt hole 124 by this measurement. Further, bolt holes corresponding to the bolt holes 126 are also formed in the air in the connecting plate 119 in advance.

  After the hole position measurement, the support plate portion 112a connected and fixed to the side wall surface of the spent fuel storage pit 100A and the support plate 118 of the new support structure 116 are connected to the connecting plate 119 using an underwater bolt / nut fastening device. The new support structure 116 is firmly positioned and fixed in the spent fuel storage pit 100A. The interval C between the rack cells 121 in the new support structure 116 is, for example, 300 mm, which is smaller than the interval between the rack cells 110 in the existing spent fuel storage rack assembly 109 is, for example, 400 mm.

  As shown in FIG. 1, the underwater drilling device described above is suspended from the auxiliary hoist 120 of the temporary crane 103 via a manipulator or an extendable pole 113 (telescopic pole portion 113a), and the existing spent fuel storage rack described above. A tool main body 10 composed of a front-side open casing that is positioned and fixed to the support plate 112 of the 111 by the clamp mechanism 11, a cutter driving device 12 assembled on the tool main body 10, and the cutter driving device 12 as an operation unit 13. A control panel 14 for controlling from the operation floor 126 on the ground using an appropriate, waste water treatment equipment 15 for sucking and collecting cutting chips generated by the cutter driving device 12 from the operation floor 126 on the ground using pit water, Is provided.

  Further, the underwater drilling device includes a core recovery tool 16 that recovers the core (cutting lump) W pushed out from the cutter driving device 12.

  The waste water treatment facility 15 purifies the cutting chips sucked and collected by the pump 18 through the chip collection hose 17 with a filter 19, and then returns filtered water to the spent fuel storage pit 100 </ b> A with a return hose 20. .

  As shown in FIG. 2, the clamp mechanism 11 moves the left and right clamp claws 31a, 31b in the direction of the arrows in the drawing by the fluid pressure cylinders 32a, 32b, thereby The tool body 10 is fixed by sandwiching the support plate 112 from the left and right directions (direction along the pit side wall surface). The tool body 10 is positioned in the front-rear direction (the direction perpendicular to the pit side wall surface) by placing at least one side end of both clamp claws 31a and 31b on the side wall surface of the spent fuel storage pit 100A. It is preferable that the contact is performed by hitting the support fitting 123 welded to the embedded plate.

  As shown in FIGS. 5A and 5B, the cutter driving device 12 includes a cutter rotating shaft 22 for mounting a trepanning cutter 21 that cuts the support plate 112 into a ring shape by rotation to form a hole, and the cutter rotation. A movable housing 24 in which a cutter rotation motor 23 that rotates the shaft 22 is housed, and the movable housing 24 are supported by a linear guide 25 so as to be movable up and down (movable in the axial direction of the cutter rotation shaft 22). A cutter feed shaft 26 that feeds the trepanning cutter 21 through the movable housing 24 and a fixed housing 28 that houses a cutter feed motor 27 that rotates the cutter feed shaft 26 are provided.

  As shown in FIG. 3A, the trepanning cutter 21 is provided with a pit water inflow hole 29 for collecting cutting chips together with the pit water by a swirling flow caused by rotation. That is, the chips are discharged to the inside of the cutter by the cutting edge angle of the trepanning cutter 21, and at this time, the pit water sucked and collected by the pump 18 from the pit water inflow hole 29 is drained through the rotary joint 30 and the chip collection hose 17. It is sent to the processing facility 15.

  Further, as shown in FIG. 3B, a piston rod 33 that pushes the core (cutting lump) W from the trepanning cutter 21 is movable up and down on the cutter rotating shaft 22 (movable in the axial direction of the cutter rotating shaft 22). To be stolen. That is, the cutting is completed and the core W remaining in the cutter is pushed out by the piston rod 33 and recovered by the core recovery tool 16 described later.

  More specifically, as shown in the core push-out state diagram of the cutter driving device in FIG. 4C, the piston rod 33 receives fluid pressure from the port P 1 of the movable housing 24 to the piston upper chamber A 1 of the cylinder 35 through the rotary joint 34. It is lowered by being supplied and pushes out the core W. On the contrary, it is raised by supplying fluid pressure from the port P2 to the piston lower chamber A2 of the cylinder 35 through the rotary joint 36, and returns to the original position. (See the installation state diagram of the cutter driving device in FIG. 4A and the cutting completion state diagram of the cutter driving device in FIG. 4B).

  Further, a trepanning cutter 21 is provided between the cutter rotating shaft 22 and a movable housing 24 that rotatably supports the cutter rotating shaft 22 with various bearings, as shown in the installation state diagram of the cutter driving device in FIG. 4A. In addition, a chip breaker mechanism 37 that provides the function of a chip breaker is interposed by finely moving the trepanning cutter 21 in the vertical direction (in the axial direction of the cutter rotating shaft 22).

  Specifically, the cutter rotating shaft 22 is divided into an upper rotating shaft 22a and a lower rotating shaft 22b, and the lower rotating shaft 22b is integrally coupled to the lower rotating shaft 22b with respect to the upper rotating shaft 22a. It is possible to move in the vertical direction through rotation. Further, the upper sleeve 39a is fitted to the lower rotary shaft 22b so that the upper sleeve 39a cannot rotate with respect to the lower rotary shaft 22b and is relatively movable in the vertical direction, and the lower sleeve 39b cannot rotate with respect to the lower rotary shaft 22b. Thus, it is fitted so that it cannot move relative to the vertical direction.

  Between the upper sleeve 39a and the lower sleeve 39b, a plurality of balls 40 rotatably supported on the movable housing 24 side and immovably supported in the circumferential direction are equally arranged in the circumferential direction and interposed. At the same time, a plurality of compression springs 41 are equally disposed in the circumferential direction between the upper sleeve 39a and the shaft coupling 38. The upper end surface of the lower sleeve 39b, on which the ball 40 rolls, is formed of a corrugated cam surface.

  Therefore, the cam surface of the lower sleeve 39b is urged upward by the compression coil spring 41 so as to always come into contact with the ball 40 via the shaft coupling 38 and the lower rotary shaft 22b. At the time of rotation, the lower rotating shaft 22b and the trepanning cutter 21 rotate together with the upper rotating shaft 22a, but only the lower rotating shaft 22b (and the trepanning cutter 21) are in the cylindrical cam of the ball 40 and the lower sleeve 39b. By the mechanism, the up and down movement is repeated slightly, and the chip breaker function is exhibited.

  Further, the cutter driving device 12 is slidably supported on the tool body 10 via the slide base 42, and can be drilled in at least two places on the support plate 112 of the existing spent fuel storage rack 111 described above. It has become.

  Specifically, as shown in FIGS. 5A and 5B, the fixed housing 28 of the cutter driving device 12 is mounted on the slide base 42, and the hydraulic pressure interposed between the slide base 42 and the tool body 10. The cylinder 43 is slidable in the front-rear direction (the direction in which the cylinder 43 comes in contact with or separates from the side wall surface of the spent fuel storage pit 100A).

  The core collection tool 16 is installed in a square hole 122 of the support plate 112, with a collection net 44 that accommodates the core W, an arm 45 that rotates the collection net 44, and the arm 45 rotatably supported. A tool base 46, a guide rope 47 connected to the tool base 46, and an operation rope 49 connected to the arm 45 through a hole 48 of the tool base 46.

  As shown in FIG. 6, when collecting the core W, first, the core collection tool 16 is suspended from the operation floor 126 via the guide rope 47 into the spent fuel storage pit 100A. At this time, the operation rope 49 is loosened (see Procedure 1). Next, the tool base 46 is tilted while applying appropriate tension to the operation rope 49 to pass through the square holes 122 of the support plate 112 in the existing spent fuel storage rack 111 at the upper part (see Procedure 2). Next, the tool base 46 is installed in the square hole 122 of the support plate 112 in the existing spent fuel storage rack 111 at the lower part while applying tension to the operation rope 49 (see Procedure 3). Next, the operation rope 49 is pulled to raise the collection net 44 to collect the core W. At this time, the operation rope 49 may be secured to a handrail or the like of the operation floor 126 (see point 4). Next, the operation rope 49 is loosened to open the collection net 44 (see Procedure 5). Next, the tool base 46 is tilted while applying appropriate tension to the operation rope 49 to pass through the square holes 122 of the support plate 112 in the existing spent fuel storage rack 111 at the lower part of the lifting (see point 6). Finally, when the tool base 46 passes through the square hole 122 of the support plate 112 in the upper existing spent fuel storage rack 111, the operation rope 49 is loosened and lifted to collect the core W.

  In FIG. 1, reference numeral 50 denotes hoses for supplying and discharging working fluid to the cutter rotation motor 23, and 51 denotes cables for supplying electric power to the cutter feed motor 27. Further, reference numeral 52 in FIG. 1 denotes tubes for supplying and discharging the working fluid to and from the fluid pressure cylinders 32a and 32b and the cylinder 35.

  When performing the reracing work using the underwater drilling device configured as described above, as described above, first, before cutting the support plates 112 of the upper and lower two existing spent fuel storage racks 111, Then, the tool body 10 of the underwater drilling device is suspended from the temporary crane 103 on the spent fuel storage pit 100A, and positioned and fixed to the support plate 112 of the existing spent fuel storage rack 111 by the clamp mechanism 11.

  Next, the cutter driving device 12 is operated to process, for example, two or more bolt holes 124 at predetermined positions on the support plate 112. After the drilling is completed, the support plate 112 is subjected to drilling. The support plate portion 112a is left and cut.

  In this way, the existing spent fuel storage rack is provided by the cutter driving device 12 on the tool body 10 that is securely positioned and fixed to the support plate 112 of the existing spent fuel storage rack 111 by the clamp mechanism 11 using the underwater drilling device. Since the support plate 112 of 111 can be smoothly drilled by remote operation from the temporary crane 103, the underwater reracing work can be safely performed in the spent fuel storage pit 100A under a high dose environment.

  In addition, when the tool body 10 of the underwater drilling device is suspended, the address plate 125 of the rack cell 110 installed on the existing spent fuel storage rack 111 is bent in advance, so that the tool body 10 interferes with the address plate 125. It can be hung smoothly without any trouble.

  Further, according to the underwater drilling device, the tool body 10 is suspended from the temporary crane 103 and positioned and fixed by the clamp mechanism 11 integrated with the tool body 10 on the support plate 112 of the existing spent fuel storage rack 111. In this state, the cutting drive by the trepanning cutter 21 is sucked and collected from the operation floor 126 using pit water, and the cutter driving device 12 is operated remotely from the control panel 14 of the operation floor 126 to support the support. Since the drilling process is performed on the plate 112, the drilling process can be performed smoothly in water while the apparatus is reliably positioned and fixed with a simple operation and structure.

  Further, a chip breaker mechanism 37 for providing the function of the chip breaker to the trepanning cutter 21 is interposed between the cutter rotating shaft 22 and the movable housing 24 of the cutter driving device 12, so that the cutting chips are shredded. And smooth chip collection.

  In addition, since the piston rod 33 that pushes out the core W from the trepanning cutter 21 is housed inside the cutter rotating shaft 22 so as to be movable in the axial direction of the cutter rotating shaft 22, the core W is reliably pushed out to collect the core. It can be recovered with the tool 16.

  Further, since the cutter driving device 12 is slidably supported by the tool body 10 via the slide base 42, any number of bolt holes can be formed in the support plate 112 quickly by simply sliding the cutter driving device 12 in water. 124 is opened.

  Moreover, since the wastewater treatment facility 15 purifies the cutting chips sucked and collected by the pump 13 with the filter 19, the filtered water is returned to the spent fuel storage pit 100A, so that the pit water does not have to be contaminated.

  Further, since the core recovery tool 16 for recovering the core W pushed out from the trepanning cutter 21 is provided so as to be remotely operable from the operation floor 126, the core W can be recovered safely.

  FIG. 7 shows a modification of the tool body. In the tool body 10 described above, the cutter rotating shaft 22 and the cutter rotating motor 23 of the cutter driving device 12 and the cutter feeding shaft 26 and the cutter feeding motor 27 are moved vertically. Although it is a so-called long type that is directly connected, the tool main body 10A in this figure includes a cutter rotation shaft 22, a cutter rotation motor 23, a cutter feed shaft 26, and a cutter feed motor 27 of the cutter driving device 12, and gear mechanisms 53 and 54, respectively. It is a so-called short type arranged horizontally.

  For example, a narrow part having a protrusion at the upper part of the drilling portion interferes with the tool body 10 having a high height, but the tool body 10A having a low height is not suitable for this purpose.

  The present invention is not limited to the above-described embodiments, and various modifications such as structural changes of various mechanisms, changes of various driving means, and changes in the number and size of various constituent members are possible without departing from the spirit of the present invention. Needless to say.

  The underwater drilling apparatus according to the present invention is not limited to underwater reracing work, but is effective when applied to other underwater works of nuclear power generation facilities (plants) and underwater works other than nuclear power generation facilities (plants).

DESCRIPTION OF SYMBOLS 10,10A Tool main body 11 Clamp mechanism 12 Cutter drive device 13 Operation unit 14 Control panel 15 Waste water treatment equipment 16 Core (cutting lump) collection tool 17 Chip collection hose 18 Pump 19 Filter 20 Return hose 21 Trepanning cutter 22 Cutter rotation shaft 22a Upper rotating shaft 22b Lower rotating shaft 23 Cutter rotating motor 24 Movable housing 25 Linear guide 26 Cutter feeding shaft 27 Cutter feeding motor 28 Fixed housing 29 Pit water inlet 30 Rotary joints 31a and 31b Clamping claws 32a and 32b Hydraulic cylinders 33 Pistons Rod 34 Rotary joint 35 Cylinder 36 Rotary joint 37 Chip breaker mechanism 38 Shaft coupling 39a Upper sleeve 39b Lower sleeve 40 Ball 41 Compression coil spring 42 Slide base 43 Fluid pressure cylinder 44 Recovery net 45 Arm 46 Tool base 47 Guide rope 48 Hole 49 Operation rope 50 Hose 51 Cables 52 Tubes 53 Gear mechanism 54 Gear mechanism 100A, 100B Spent fuel storage pit (pool)
DESCRIPTION OF SYMBOLS 101 Spent fuel storage pit crane 102 Existing rail 103 Temporary crane 104 Wire jack 105 Rack stand 106 Fuel inspection pit 107 Decontamination field pit 108 Temporary floor 109 Existing spent fuel storage rack assembly 110 Rack cell 111 Existing spent fuel storage rack 112 Support plate (structure)
112a Support plate part (pit side wall side)
DESCRIPTION OF SYMBOLS 113 Manipulator or telescopic pole 113a Telescopic pole part 114 Tool body of underwater electrical discharge machining cutting device 115 Existing spent fuel storage rack hanging tool 116 New support structure (new spent fuel storage rack)
117 New support structure lifting device 118 Support plate 119 Connecting plate 120 Auxiliary hoist 121 Rack cell 122 Square hole 123 Support bracket 124 Bolt hole 125 Address plate 126 Operation floor 127 Bolt hole 128 Bolt / nut A1 Piston upper chamber A2 Piston lower chamber C New support Rack cell spacing in structure P1, P2 Port W core (cutting lump)

Claims (10)

An underwater drilling device that drills holes in the structure in the pit.
A tool body suspended from the ground and positioned and fixed to the structure by a clamp mechanism;
A cutter driving device assembled on the tool body;
A control panel for controlling the cutter driving device from the ground using an operation unit as appropriate;
Wastewater treatment equipment for sucking and collecting cutting chips generated by the cutter driving device from the ground using pit water,
With
The cutter driving device includes a movable housing in which a cutter rotating shaft for mounting a trepanning cutter that cuts the structure into a ring shape by rotation to form a hole and a cutter rotating motor that rotates the cutter rotating shaft are accommodated. A cutter feed shaft that supports the movable housing so as to be movable in the axial direction of the cutter rotating shaft, and applies feed to the trepanning cutter via the movable housing; and a cutter feed motor that rotates the cutter feed shaft. The trepanning cutter is provided with a pit water inflow hole for collecting cutting chips together with the pit water by a swirling vortex by rotation,
An underwater drilling device characterized by that. Between the cutter rotating shaft and the movable housing, a chip breaker mechanism for providing a function of a chip breaker to the trepanning cutter is interposed.
The underwater drilling device according to claim 1, wherein: Inside the cutter rotating shaft, a piston rod that pushes a cutting lump out of the trepanning cutter is accommodated so as to be movable in the axial direction of the cutter rotating shaft.
The underwater drilling device according to claim 1 or 2, characterized in that. The cutter driving device is slidably supported on the tool body via a slide base, and can drill holes in at least two locations of the structure.
The underwater drilling device according to claim 1, 2, or 3. The waste water treatment facility is to clean the cutting chips sucked and collected by a pump with filters, and then return the filtered water to the pit.
The underwater drilling device according to claim 1, 2, 3, or 4. Furthermore, a cut lump collection tool for collecting a cut lump extruded from the trepanning cutter is provided so that it can be remotely operated from the ground.
The underwater drilling device according to claim 1, 2, 3, 4 or 5. The tool body is a so-called long type in which the cutter rotation shaft and the cutter rotation motor of the cutter driving device and the cutter feed shaft and the cutter feed motor are directly connected to each other vertically.
The underwater drilling device according to claim 1, 2, 3, 4, 5 or 6. The tool body is a so-called short type in which the cutter rotation shaft and the cutter rotation motor of the cutter driving device and the cutter feed shaft and the cutter feed motor are horizontally arranged via gear mechanisms, respectively.
The underwater drilling device according to claim 1, 2, 3, 4, 5 or 6. After the existing spent fuel storage rack composed of a plurality of rack cells installed in the spent fuel storage pit is lifted and removed by cutting the support plate provided on the outer periphery thereof, the density of the rack cells becomes the existing spent fuel storage rack. When installing a new spent fuel storage rack that is set higher than that of the existing spent fuel storage rack, a support plate provided on the outer periphery of the new used fuel storage rack and the existing use left in the spent fuel storage pit In underwater reracking work that bolts the support plate part of the spent fuel storage rack through the connecting plate,
Prior to cutting the support plate of the existing spent fuel storage rack,
After the tool body of the underwater drilling device according to any one of claims 1 to 8 is suspended and fixed to the support plate of the existing spent fuel storage rack by a clamp mechanism,
After operating the cutter driving device to make one or more holes in a predetermined position of the support plate,
The support plate is cut leaving the support plate portion subjected to the drilling process,
Underwater reracking method characterized by that. When hanging the tool body of the underwater drilling device, the address plate of the rack cell installed on the existing spent fuel storage rack is bent in advance.
The underwater reracing method according to claim 9.

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