JPH10100023A - Remote cutting device - Google Patents

Abstract

(57) [Summary] Means for cutting stud bolts by an approach of a cutting tool from the upper surface of a core support plate, and remotely collecting stud bolt cutting pieces outside the furnace, and stud bolts to be cut Provided is a remote cutting device having a function of efficiently performing installation of the device on the remote cutting device. A cutting head provided with a plate-shaped electric discharge machining electrode.
And a support mechanism 3 that is seated on the core support plate and holds the cutting head 2 so that the discharge direction of the electric discharge machining electrode is inclined at a predetermined angle with respect to the upper surface of the core support plate, and captures a section of the stud bolt 103. The remote cutting device 1 is provided with the section capturing device 4 having the bucket 16 to be cut.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote cutting apparatus for cutting and removing a structure in a nuclear reactor, in particular, a stud bolt for fixing a core support plate to a shroud.

[0002]

2. Description of the Related Art In a nuclear reactor, a core support plate is fixed to a pressure vessel with a number of stud bolts. After installation of the core support plate during construction, the stud bolts are welded and fixed to prevent falling off. For this reason, when removing the core support plate during the dismantling work or repair work of the nuclear reactor, it is necessary to cut the stud bolt and collect it outside the reactor.

[0003] In the conventional dismantling and repair work of a nuclear reactor, after cleaning radiation contaminants in the reactor, a radiation partition is provided in the working environment, workers are put in, and the reactor internal structure is cut manually. Did the work. Alternatively, for example, see
As disclosed in Japanese Unexamined Patent Publication No. 228986, a cutting device was put into a furnace to perform a cutting operation. On the other hand, the following two methods can be considered as means for cutting and collecting stud bolts using a remote cutting device in a furnace.

[0004] 1) A cutting tool is inserted between the end of the core support plate and the inner wall surface of the shroud to cut and separate the intermediate portion of the stud bolt, and the upper cut piece of the stud bolt is left on the core support plate, and the stud is removed. The lower cut piece of the bolt is dropped toward the furnace bottom.

2) On the upper surface of the core support plate, the bolt head of the stud bolt is cut and separated by a cutting tool, and the upper cut piece of the stud bolt is collected from the core support plate. And drop it.

[0006]

First, when stud bolts are cut and recovered on the premise of manual operation in a conventional furnace, the influence of activation is highest even when the core support plate is in the furnace.
In addition, due to the large number of stud bolts, manual work is not possible or the working time per worker is severely restricted, resulting in an increase in labor costs and a prolonged construction period.

On the other hand, the cutting and collecting means using the remote cutting device has the following problems.

The method for cutting stud bolts pointed out in the prior art 1) has an advantage that the upper cut pieces of the stud bolts can be simultaneously collected while hanging on the core support plate.
The clearance between the end of the core support plate and the inner wall surface of the shroud is about several centimeters, and there is a limit to the design of a cutting tool that can be inserted.

On the other hand, in the method of cutting stud bolts pointed out in the prior art 2), it is necessary to individually collect the cut pieces of the bolt head with attached parts such as washers, and furthermore, the cut pieces are dissipated inside the furnace. With danger.

Further, both of the prior arts 1) and 2) require means for collecting the lower cut piece of the stud bolt at the lower portion of the core support plate, and the lower cut piece recovery means is a CRD passage hole of the core support plate. To be installed at the lower part of the core support plate. Furthermore, in order to shorten the construction period, it is necessary to efficiently install a remote cutting device on a large number of stud bolts.

An object of the present invention is to cut stud bolts by an approach of a cutting tool from the upper surface of a core support plate,
In addition, the bolt head after cutting can be stably left on the core support plate, or peripheral parts such as the bolt head and washer can be eliminated at the same time as the cutting operation, and the lower cut piece of the stud bolt can be remotely operated. It is an object of the present invention to provide a remote cutting device having a function capable of recovering waste and having a function of efficiently installing the device on a stud bolt to be cut.

[0012]

[Means for Solving the Problems]

1) An object of the present invention is to provide a cutting head composed of a plate-shaped electric discharge machining electrode and a discharge mechanism of the electric discharge machining electrode, and a discharge direction of the electric discharge machining electrode seated on the core support plate and with respect to the upper surface of the core support plate. A supporting mechanism for holding the cutting head so as to be inclined at a predetermined angle, a bucket provided at a lower portion of the core support plate to capture a piece of a stud bolt to be cut, a degree of freedom and a bucket for rotating and driving the bucket about a vertical axis. And a section capturing device having a degree of freedom to be fed out in the horizontal direction.

2) An object of the present invention is to provide a cutting head configured to inject a cutting medium such as a plasma torch or a water jet cutting tool and cut an object, and a cutting head that is seated on a core support plate and is positioned above the core support plate. A support mechanism that holds the cutting head so that the injection direction of the cutting medium is inclined at a predetermined angle,
A bucket provided at a lower portion of the core support plate for capturing a section of a stud bolt to be cut, a section capturing apparatus having a degree of freedom for driving the bucket to rotate around a vertical axis and a degree of freedom for horizontally extending the bucket; This is achieved by configuring a cutting device.

3) An object of the present invention is to provide a machining head composed of an electric discharge machining electrode and an electric discharge machining electrode feeding mechanism, and a direction in which the electric discharge machining electrode is seated on the core support plate and is extended in a longitudinal direction of the stud bolt. A support mechanism for holding the processing head so as to be parallel, a bucket provided at the lower part of the core support plate for capturing a piece of a stud bolt to be cut, a degree of freedom for rotating the bucket about a vertical axis, and a horizontal direction for the bucket. And a section capturing device having a degree of freedom to be fed to the remote cutting device.

4) The object of the present invention is achieved by configuring the support mechanism described in 1), 2) and 3) as a multi-joint mechanism seated in a CRD passage hole of a core support plate. You.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram illustrating an overall configuration of a remote cutting device 1 according to the present embodiment. FIG. 2 is a diagram showing a detailed structure of the cutting head 2 of this embodiment and a cutting operation state.
FIG. 3 is a diagram showing a working state of the section capturing device 4 of the present embodiment. 1, 2 and 3, the same components are denoted by the same reference numerals.

As shown in FIG. 1, the upper lattice plate 100 is
The shroud 101 is held on the upper surface of the protrusion 102 and is fastened and fixed by a stud bolt 103 and a nut 105 penetrating the protrusion 102 from the upper lattice plate 100. Here, the bolt head 104 above the stud bolt 103 is fixed to the stud bolt 103 by welding in order to prevent the bolt head 104 from falling off.

As shown in FIG. 1, a remote cutting device 1 includes a cutting head 2 for performing a cutting process, a support mechanism 3 for positioning the position and posture of the cutting head 2 with respect to a cutting target, and a lower cutting of a stud bolt 103. It comprises a section capturing device 4 for capturing and recovering the pieces 108.

As shown in FIG. 2, the cutting head 2 has a plate-shaped electric discharge machining electrode 30 provided on a support plate 31. The support plate 31 is provided with a rail 35 on a base frame 34 and slide bearings 32 and 33. , Is slidably supported on the base frame 34. Further, the electric discharge machining electrode 30 is fed and drawn into and out of the base frame 34 by a ball screw 38 driven to rotate by an electrode feed motor 37 and a nut 36 provided on the support plate 31. Further, the cutting head 2 is connected to the support mechanism 3 via the flange 11 such that the feeding direction of the electric discharge machining electrode 30 is inclined at a predetermined angle with respect to the upper surface of the core support plate 100.

As shown in FIG. 1, the support mechanism 3 includes an installation portion 12, a first joint 5 having a rotational degree of freedom, a first link 8, a second joint 6 having a rotational degree of freedom, It comprises two links 9 and a wrist joint 7, and the wrist joint 7 has a degree of freedom to rotate the ball spline shaft 10 in the vertical direction and around the vertical axis. The cutting head 2 and the support mechanism 3 are connected by a flange 11 provided at the tip of a ball spline shaft 10. The mounting portion 12 has a seating portion 13 which sits in the CRD passage hole 106, and pushes and expands the clamp 15 by rotating a screw 14, and is fixed to the core support plate 100.

The positioning of the cutting head 2 in the horizontal plane is performed by driving the first joint 5 and the second joint 6 and operating the first link 8 and the second link 9.
Further, the positioning of the cutting head 2 in the vertical direction and the determination of the attitude in the horizontal plane are performed by driving the wrist joint 7 and rotating the ball spline shaft 10 up and down.

Next, the section capturing device 4 includes the
2 and is located below the core support plate 100 with the remote cutting device 1 installed on the core support plate 100. The section capturing device 4 includes a stud bolt 10
Bucket 16 for capturing the lower cut piece 108 of the third
A turning mechanism 17 provided at the lower end of the installation portion 12 for turning the bucket 16 around a vertical direction;
6 for pushing out the sheet 6 toward the shroud 101
It is composed of The payout mechanism 18 includes the turning mechanism 17.
, A drive block 21 slidably supported in the longitudinal direction of the support pole 19 and driven linearly by an actuator 20, and links 22 and 23. The link 23 is connected to the drive block 21 by a rotating hinge 24, and is connected to the bucket 16 by a rotating hinge 25.
Is connected to the upper end. Further, the link 22 is connected to the support pole 19 by a rotating hinge 26, and is connected to the center between the axes of the rotating hinges 24 and 25 on the link 22 by a rotating hinge 27.

With this configuration, the bucket 16 can be driven in the horizontal direction by driving the actuator 20.

When the bucket 16 is pulled toward the support pole 19 as shown in FIG.
Has a shape that can pass through the CRD passage hole. Further, the lower cut piece 1
A hatch 28 for discharging 08 is provided, and the hatch 28 can be opened and closed by an actuator 29.

Next, the operation of this embodiment will be described with reference to FIGS. 1, 2 and 3. FIG.

First, as for the installation of the remote cutting device 1, as shown in FIG. 3, with the bucket 16 pulled in, the section capturing device 4 is passed through the CRD passage hole, and as shown in FIG. The apparatus is seated and fixed on a core support plate 100. Thereafter, as shown in FIG. 3, the turning mechanism 17 and the feeding mechanism 18 are remotely operated to position the bucket 16 immediately below the stud bolt 103 to be cut. At this time, as shown in FIG.
With five degrees of freedom, the shroud 101 is fitted and attached to the inner wall surface of the inclined portion 107 of the shroud 101.

Next, as for the cutting operation, as shown in FIG. 2, by remotely operating the support mechanism 3, the electric discharge machining electrode 30 is positioned near the bolt head 104.
Electric discharge machining is performed, and both the core support plate 100 and the stud bolt 103 are cut in the inclined direction. In this operation, when the stud bolt 103 is cut, the cut lower cut piece 108 falls and is captured by the bucket 16.

Next, after the cutting operation is completed, the bucket 1
6 is positioned below the next stud bolt 103 to be cut, and the cutting mechanism 2 is moved by the support mechanism 3 to the stud bolt 103 to be cut.
Positioning in the vicinity of 04 and the cutting operation are repeated. This operation is repeated to accumulate the lower cut pieces 108 in the bucket 16, and when the predetermined amount is accumulated, the bucket 16 is stored, and the remote cutting device 1 is moved from the core support plate 100 to the lower cut piece 108 provided elsewhere. Move to above the collection area and use hatch 28
Is released, the lower cut pieces 108 accumulated in the bucket 16 are discharged.

Thereafter, the remote cutting device 1 is installed in another CRD passage hole 106 and the same operation is repeated to cut all the stud bolts 103 fixing the core support plate 100. Further, after removing the remote cutting device 1, the core support plate 100 is lifted horizontally, moved to a position where the articles do not fall into the furnace, and the stud bolts 103 remaining on the core support plate 100 are collected. Do.

According to this embodiment described above, after the stud bolt 103 is cut, the upper cut piece is placed in the core support plate 1.
Since it remains inserted in the bolt holes of No. 00, it can be collected outside the furnace together with the core support plate 100 without being dropped inside the furnace.

Further, the lower cut piece 108 is
6 and can be collected outside the furnace. Furthermore, the approach of the stud bolts 103 to the cutting head 2 is performed in the upper space of the upper lattice plate 100 where there is little interference, so that there are few restrictions on the size and shape of the cutting head 2.

Further, since the installation positioning of the cutting head 2 is performed by the support mechanism 3 having a multi-degree-of-freedom mechanism, and the bucket 16 can be arbitrarily positioned under the core support plate 100, one remote cutting operation is performed. With the installation of the apparatus 1 on the core support plate 100, a cutting operation of the plurality of stud bolts 103 can be executed.

Another embodiment of the present invention will be described with reference to FIG.

FIG. 4 is a view for explaining the cutting state of the cutting head 40 of the remote cutting device 39 of this embodiment. 4, the same components as those in FIGS. 1 to 3 are denoted by the same reference numerals.

As shown in FIG. 4, the cutting head 40 of the present embodiment is configured to cut a target object by injecting a cutting medium 41 such as a plasma torch or a water jet cutting tool. The cutting medium 41 is installed on the flange 11 such that the injection direction of the cutting medium 41 is inclined at a predetermined angle with respect to the upper surface of the core support plate 100. In such a configuration, the core support plate 100 and the stud bolts 103 are obliquely cut off by moving the cutting head 40 in the normal direction of the paper of FIG.

According to the present embodiment described above, since a plasma torch, a water jet, or the like is used as a cutting tool, the cutting operation can be performed at a higher speed than the embodiment shown in FIG.

Another embodiment of the present invention will be described with reference to FIG.

FIG. 5 is a view for explaining the cutting state of the cutting head 43 of the remote cutting device 42 of this embodiment. 4, the same components as those in FIGS. 1 to 3 are denoted by the same reference numerals.

In the cutting head 43 of the present embodiment, the electric discharge machining electrode 44 has a block-like shape, and the base frame 45 is mounted on the flange 11 so that the direction in which the electric discharge machining electrode 44 extends is substantially vertical. It is configured to be combined. In such a configuration, after the cutting head 43 is positioned by the support mechanism 3 so that the bottom surface of the electric discharge machining electrode 44 is located directly above the bolt head 104, the electric discharge machining electrode 44 is lowered, and the bolt is formed by electric discharge machining. Head 10
4. Melt and remove the whole. When the bolt head 104 on the core support plate 100 is completely removed, the lower cut piece 108 of the stud bolt 103 is collected in the bucket 16.

According to the present embodiment described above, unlike the embodiment shown in FIG. 1, the core support plate 1 does not leave the upper cut piece of the stud bolt 103 on the core support plate 100.
Since 00 can be moved, the danger of the cut pieces falling to the furnace bottom can be further reduced.

Another embodiment of the present invention will be described with reference to FIG.

FIG. 6 is a view for explaining the overall configuration of the cutting device 46 of this embodiment. 6, the same components as those in FIGS. 1 to 3 are denoted by the same reference numerals.

The cutting head 47 of this embodiment is the same in function and structure as the cutting head 2 shown in FIG. 2 except for the configuration of the base frame 48. The support mechanism 46 of the present embodiment sits on the core support plate 100 with the positioning caps 50 and 51 covering the two bolt heads 104 as scaffolds, and uniquely determines the position and posture of the cutting head 47 connected via the base frame 48. Stipulate.

According to this embodiment described above, the structure of the apparatus can be simplified as compared with the case where the support mechanism is constituted by a multi-degree-of-freedom mechanism as in the embodiment shown in FIG. The positioning accuracy can be increased, and the reliability of the cutting operation can be increased.

[0045]

According to the present invention, stud bolts for fixing the core support plate to the shroud are attached to the bottom of the reactor in the work of removing the core support plate generated during the repair work or the decommissioning work of the reactor. It can be cut and removed without dropping. Furthermore, since the work of installing the cutting head and the section capturing device on the plurality of stud bolts can be flexibly executed by the multi-degree-of-freedom mechanism, the time required for re-installing the device for each cut can be reduced, and an efficient cutting operation can be realized. . In addition, charging the remote cutting device into the furnace,
Since a series of disassembly operations such as cutting work, recovery of the core support plate, and stud bolts can be performed from outside the furnace by remote control, the working process can be shortened and the construction cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a cutting head according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a section capturing device according to an embodiment of the present invention.

FIG. 4 is an explanatory view of a cutting head according to another embodiment of the present invention.

FIG. 5 is an explanatory view of a cutting head according to another embodiment of the present invention.

FIG. 6 is a diagram showing an overall configuration of another embodiment of the present invention.

[Explanation of symbols]

1, 39, 42, 46 ... remote cutting device, 2, 40, 4
3, 47 cutting head, 3, 49 supporting mechanism, 4 section capturing device, 5 first joint, 6 second joint, 7 wrist joint, 8 first link, 9 second link , 10 ... ball spline shaft, 11 ... flange, 12 ... installation part, 13 ... seating part, 14 ... screw, 15 ... clamp, 1
6 bucket, 17 rotating mechanism, 18 feeding mechanism,
19 ... support pole, 20, 29 ... actuator, 21
... Driving block, 22, 23 ... Link, 24, 25, 2
6, 27 ... rotating hinge, 28 ... hatch, 30, 44 ... electric discharge machining electrode, 31 ... support plate, 32, 33 ... slide bearing, 34, 45, 48 ... base frame, 35 ... rail, 36 ... nut, 37 ... Electrode feed motor, 38 ball screw, 41 cutting medium, 50, 51 cap, 100 core support plate, 101 shroud, 102
... projecting part, 103 ... stud bolt, 104 ... bolt head, 105 ... nut, 106 ... CRD passage hole, 107
... Inclined part, 108.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Takao Shimura 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant (72) Inventor Shinya Omori 3-chome, Sachicho, Hitachi-shi, Ibaraki No. 1 Inside Hitachi, Ltd. Hitachi Plant (72) Inventor Nobuo Tada 3-1-1 Sachimachi, Hitachi-shi, Ibaraki Prefecture Inside Hitachi Ltd. Hitachi Plant (72) Inventor Hiroshi Muto, Hitachi-shi, Ibaraki 3-1-1, Machi, Hitachi, Ltd. Hitachi Plant

Claims (4)

[Claims] In a remote cutting apparatus for cutting a stud bolt for fixing a core support plate of a nuclear reactor, a cutting head comprising a plate-like electric discharge machining electrode and a discharge mechanism of an electric discharge machining electrode; A support mechanism that holds the cutting head so as to be seated and tilts the discharge direction of the EDM electrode at a predetermined angle with respect to the upper surface of the core support plate, and captures a stud bolt section provided at the lower portion of the core support plate to be cut. 1. A remote cutting device, comprising: a bucket, a section capturing device having a degree of freedom for rotating the bucket about a vertical axis, and a degree of freedom for extending the bucket in a horizontal direction. 2. A cutting head configured to cut a target object by injecting a cutting medium such as a plasma torch or a water jet cutting tool in a remote cutting device for cutting a stud bolt for fixing a core support plate of a nuclear reactor, A support mechanism that sits on the core support plate and holds the cutting head so that the injection direction of the cutting medium is inclined at a predetermined angle with respect to the upper surface of the core support plate; and a stud bolt provided at the lower portion of the core support plate and to be cut. A remote cutting device, comprising: a bucket for capturing a section; a section capturing device having a degree of freedom for pivotally driving the bucket about a vertical axis and a degree of freedom for extending the bucket in a horizontal direction. 3. A remote cutting apparatus for cutting a stud bolt for fixing a core support plate of a nuclear reactor, a machining head comprising an electric discharge machining electrode and a discharge mechanism of an electric discharge machining electrode; A supporting mechanism for holding the machining head so that the discharge direction of the electric discharge machining electrode is substantially parallel to the longitudinal direction of the stud bolt, a bucket provided at a lower portion of the core support plate to capture a section of the stud bolt to be cut, a bucket; And a section capturing device having a degree of freedom to rotate around a vertical axis and a degree to feed out a bucket in a horizontal direction. 4. The remote cutting device according to claim 1, wherein the support mechanism comprises a multi-joint mechanism seated in a CRD passage hole of the core support plate.