JP2004061395A - Cutting-assisting apparatus for dismantling reactor pressure vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting-assisting apparatus for dismantling a reactor pressure vessel, which is useful and highly feasible and enhances the safety of cutting work and stability by easily assisting the cutting work appropriately at a low cost, in place of one with a high degree of difficulty associated directly with increase in cost. <P>SOLUTION: When the reactor pressure vessel is cut from an inside, a support device for supporting an end part of the vessel from a bottom side is provided and the support device is constituted of a parallel link mechanism controlled to balance the support device by at least three sets of piston cylinder systems. A cut piece is held horizontally by the parallel link systems, and the cut pieces are stacked one on top of another, starting from the bottom side to the top side, without changing the positions by maintaining horizontality. Thus, safety in work and stability are highly enhanced, without causing slippages or shift at cut faces. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disassembly assisting device for dismantling a reactor pressure vessel, which is used for cutting a reactor pressure vessel used as a central device of the nuclear plant when dismantling the nuclear plant or the like.
[0002]
[Prior art]
A nuclear power plant developed as a typical example of the peaceful use of nuclear power has been commercialized in Japan for over 30 years and less than 40 years (Japan Nuclear Power Tokai Power Plant: 1966 (Commercial operation commenced in July), and there have been few cases where the operation was terminated during this period, and since there is a certain cooling period required after the operation is completed, there has been no example of actual dismantling.
[0003]
However, in Europe and the United States, which is ahead of Japan in this field, actual examples of dismantling have begun to appear.Particularly, as a treatment of a pressure vessel that hits a heavy structure, after filling the inside of the pressure vessel with concrete etc., bury it deep underground A method or a method of cutting the pressure vessel into a plurality of pieces and burying the same in the ground in the same manner as described above is employed.
[0004]
Among these methods, when looking at the cutting process, a turntable is installed at the bottom of the pressure vessel that extends vertically and is installed at the side space position of the pressure vessel that is installed vertically. A cutting device is arranged, the cutting device is operated from the side peripheral surface while rotating the pressure vessel with a turntable, and the image of the cutting device that cuts with a cutting tool from the peripheral surface of the work rotating around the vertical axis is used as the pressure container. May be sliced along a horizontal plane perpendicular to the vertical axis.
[0005]
Further, as another cutting method, an arc cutting device or a plasma cutting device is taken in and installed in the pressure vessel that extends in the vertical direction and is erected, and these cutting devices are installed vertically in the pressure vessel. In some cases, the pressure vessel is moved along the inner peripheral surface of the same pressure vessel in a horizontal plane perpendicular to the axis, and cut in the same manner as above.
[0006]
[Problems to be solved by the invention]
However, among the cutting methods for cutting a pressure vessel in the United States and Europe, which are performed while rotating the pressure vessel with a turntable, the pressure vessel is connected with various conduits under the pressure vessel. It is necessary to carry out the parts from the narrow space provided in the space, assemble the turntable, and install it so that the pressure vessel is supported from the lower surface, which is a difficult task in a very limited space, Preparatory work involving labor, work exposure and cost is required.
[0007]
Also, in the case of cutting from the inside of the pressure vessel by a thermal cutting method such as an arc cutting device or a plasma cutting device, a large amount of cutting gas, fumes and molten residues are generated, and radioactive substances are generated by these gases and fumes. It is necessary to take care to avoid mixing, adhering, scattering and diffusion into the wastewater. For this reason, special waste gas treatment equipment is required for safety, for example, a filter for removing particulate matter and a filter for removing molecular matter are required. And the like, and the cost must be increased.
[0008]
In such a situation, the present invention requires a high degree of difficulty in dismantling a pressure vessel, whose necessity is expected to further increase in Japan in the near future, such as a cutting method that is leading in Europe and the United States. A useful and feasible reactor pressure vessel that is easy and inexpensive to replace the one that directly leads to increased costs, and that can appropriately support the cutting operation and increase the safety and stability of the operation. It is an object of the present invention to provide a cutting assisting device for dismantling.
[0009]
[Means for Solving the Problems]
The present invention has been made in order to solve the above-mentioned problem, and moves along a plurality of cutting planes that are orthogonal to the longitudinal axis of the reactor pressure vessel in the horizontal direction and are parallel to the longitudinal axis direction to move the reactor pressure vessel. It has a cutting device for cutting the vessel from the inside, and a support device that is arranged at the lower part in the axial direction of the reactor pressure vessel and supports the mirror portion of the pressure vessel from below. The support devices balance each other. The present invention provides a cutting assisting device for dismantling a reactor pressure vessel constituted by a parallel link mechanism comprising three or more sets of piston and cylinder devices controlled by the pressure control.
[0010]
That is, according to the present invention, inside the reactor pressure vessel, while having a cutting device that moves along the cut surface and cuts the reactor pressure vessel from the inside, the axially lower part of the reactor pressure vessel Has a supporting device for supporting the mirror portion of the pressure vessel from below, and this supporting device is constituted by a parallel link mechanism comprising three or more sets of piston and cylinder devices and controlled so as to balance each other. When cutting a plurality of cutting planes that are perpendicular to the vertical axis of the pressure vessel in the horizontal direction and parallel to the vertical axis direction from the lower cutting plane to the upper one, the cutting that has finished cutting The cut pieces separated from the reactor pressure vessel at the surface are adjusted and controlled by a parallel link mechanism and supported at a predetermined position, and maintain the levelness from the lower one to the upper one without breaking the position. Stacked one by one Without causing slipping and misalignment in the cut surface which is, in which as much increase work safety, stability.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is an explanatory view schematically illustrating an outline of a cutting assisting apparatus for dismantling a reactor pressure vessel according to the present embodiment, FIG. 2 is an explanatory view conceptually illustrating a cutting apparatus directly used for cutting, and FIG. FIG. 2 is an explanatory view showing in detail a disassembly cutting assist device including a support lifter schematically shown in FIG. 1.
[0012]
The mainstream of commercial nuclear reactors is a so-called light water reactor using water (H ₂ O) as a coolant, but the light water reactor is further divided into a boiling water type and a pressurized water type. You.
[0013]
The boiling water reactor pressure vessel and the pressurized water reactor pressure vessel have the same basic structure in which both the reactor pressure vessels are erected upright, but the latter is a pressure vessel. In order to circulate the primary coolant to the outside, the inlet and outlet bulges like a nozzle, and the support part of the pressure vessel can be formed here. The support structure will be different.
[0014]
Although there is a difference as described above, both are likely to be exposed to the place of dismantling in the near future, and both will require an efficient dismantling method, but in this embodiment, A pressurized water reactor pressure vessel will be described below as a direct object, and a boiling water reactor pressure vessel can be applied as an applied modification thereof.
[0015]
That is, in the present embodiment, reference numeral 1 denotes a pressure vessel of a nuclear reactor, in which a lower mirror 1a is supported by a support lifter 3 and is installed in an installation space 4 surrounded by a partition wall 8 made of concrete or the like. I have.
[0016]
Here, the pressure vessel 1, after a commercial operation for a certain period determined as, for example, 30 years, after a further cooling period of 5 to 10 years in consideration of the decay period of radioactivity, The fuel rod and the control rod are removed, and the pressure vessel 1 itself is shown as being imagined to be dismantled.
[0017]
The pressure vessel 1 is in a state where it is scheduled to be cut into a plurality of pieces along a horizontal plane orthogonal to its axis, and a plurality of cutting lines 2 (cutting lines 2) Are included in the cut surface. In the present specification, the cut surface is a general term for both the surface to be cut and the cut surface.)
[0018]
The upper portion of the pressure vessel 1 is supported by the upper end support portion 7, and the lower portion is supported by the support lifter 3 installed in the lower space 6 by appropriate means.
[0019]
FIG. 2 conceptually shows a cutting device for cutting the pressure vessel 1 with a cutting tool along a cutting line 2. Reference numeral 10 denotes an upper pedestal installed on the pressure vessel 1 for this cutting operation; Is a hoist placed on the upper gantry 10, and the hoist 11 is connected to a support 13 arranged in the pressure vessel 1 by a cable covered with a cover 12, so that the support 13 can be moved vertically. ing.
[0020]
The support base 13 rotates to cut the wall surface of the pressure vessel 1, a main drive motor 19 that rotationally drives the cutting blade 15, and moves the cutting blade 15 along the peripheral surface of the pressure vessel 1. A turning motor 16, an elevating motor 17 that enables the cutting blade 15 to move up and down, and a radial feed that sends the cutting blade 15 radially toward the wall surface of the pressure vessel 1 to cut and cut the wall surface. The motor 18 and the like are supported.
[0021]
The support table 13 is formed of a disk-shaped or radial arm-shaped member centered on the axis of the pressure vessel 1, and clamps 14 at three or more positions on the outer circumference circle, preferably at four positions at 90 ° intervals. It is provided so that the position of the support base 13 can be fixed with respect to the pressure vessel 1 so that the horizontality of the cut surface is maintained.
[0022]
FIG. 3 shows details of the support lifter 3 schematically shown in FIG. 1 and a cutting assist device including the support lifter 3 and cooperating with each other when cutting by the cutting device.
In other words, the support lifter 3 is configured such that a plurality of arm members are sequentially pin-connected at the ends, and the parallel link 36 installed on the upper surface by extending and contracting in a bellows shape in the vertical direction can be moved up and down.
[0023]
The parallel link 36 is composed of four sets of pistons and cylinders. One end of the pistons and cylinders is connected to the support lifter 3 and the other end is connected to the cradle 31. The detecting device (not shown) detects the expansion and contraction state of the piston. The expansion and contraction of the respective pistons and cylinders are mutually adjusted by a control device (not shown), so that the receiving table 31 is held horizontally.
[0024]
The support 31 is provided with an annular support portion 32 at the upper end thereof, and supports the pressure vessel 1 via the support portion 32. Therefore, the support 31 is horizontally moved by the parallel link 36 as described above. By controlling the degree, the pressure vessel 1 is also supported while maintaining the levelness.
[0025]
The cradle 31 has a hopper 33, a chip discharge pipe 34 communicating with the hopper 33, and a vibration device 35 that engages with the bottom surface of the hopper 33 to apply vibration to the hopper 33. When the pressure vessel 1 is cut or cut, the chips 2 a and the like are collected in the hopper 33 and can be reliably discharged to the outside through the chip discharge pipe 34.
[0026]
In addition, the support lifter 3 is provided with a moving wheel 37 at a lower portion, and the support lifter 3 including the cradle 31 is moved to a position where the pressure vessel 1 is supported and set. After the device 3 is installed at the predetermined position, the position is not changed by an appropriate lock device.
[0027]
In the present embodiment configured as described above, when cutting the pressure vessel 1, the support lifter 3 is disposed below the pressure vessel 1, and is installed at a position where the pressure vessel 1 can be stably supported. The pressure vessel 1 is supported via the pedestal 31.
[0028]
Next, as shown in FIG. 2, the cutting device is installed inside the pressure vessel 1, the support 13 is positioned with respect to the predetermined cutting line 2 by the clamp 14, and the cutting line 2 is The cutting position of the pressure vessel 1 is determined by determining a position where the cutting blade 15 fits.
[0029]
The pressure vessel 1 has a thickness of about 100 to 250 mm, while the cutting of the cutting blade 15 cut in the thickness direction by the radial feed motor 18, that is, the radial direction of the pressure vessel 1, is about 10 to 20 mm per stroke. Therefore, the cutting blade 15 makes use of the turning motor 16 in addition to the diameter feed motor 18 to repeatedly perform cutting in the thickness direction and cutting in the circumferential direction, and the cutting proceeds along the cutting line 2. .
[0030]
The cutting line 2 is orthogonal to the longitudinal axis of the pressure vessel 1 in the horizontal direction, and the cutting line 2 is scheduled in a plurality of planes parallel to the longitudinal axis direction. Of these, the cutting is performed sequentially from the one located below.
[0031]
Therefore, the part including the mirror part 1a of the pressure vessel 1 is cut first, but this part is supported by the pedestal 31 via the support part 32, and supported by the parallel link 36 while maintaining the levelness. The predetermined position is held by the lifter 3.
[0032]
Next, cutting is performed along the cutting line 2 that is second from the bottom.
The cutting is performed by using the turning motor 16, the lifting motor 17, the radial feed motor 18 and the main drive motor 19 in the same manner as the cutting line 2 of the portion including the mirror portion 1a. When the cutting of the line 2 is completed, the cut pieces that have been cut here will be superimposed on the first cut pieces by their own weights.
[0033]
At this time, since the first cut piece is kept horizontal by the parallel link 36 as described above, the second cut piece is stably mounted thereon, and in that state, the parallel cut is further performed by the parallel link 36. The horizontality is adjusted and maintained, and the horizontality is similarly maintained for the third and fourth cut pieces.
[0034]
Thus, according to the present embodiment, the cut pieces sequentially cut from below along the predetermined cutting line 2 are sequentially cut from the lower one to the upper one while maintaining the horizontality without changing the position. The safety and stability of the work can be remarkably improved without causing slippage or slippage on the cut and stacked cut surfaces.
[0035]
The cutting in the present embodiment is carried out in the air using the cutting blade 15 from the inside of the pressure vessel 1 along the cutting line 2, so that the cutting is independent of the generation of cutting gas and fume. No scattering and diffusion of the pressure vessel, the cost was kept low with a simple device, safe and reliable cutting was performed, and the pressure vessel was effectively dismantled.
[0036]
As described above, the present invention has been described with reference to the illustrated embodiments. However, the present invention is not limited to such embodiments, and it goes without saying that various changes may be made to the specific structure within the scope of the present invention. Absent.
[0037]
【The invention's effect】
As described above, according to the invention of the present application, the reactor pressure vessel is cut from the inside by moving along a plurality of cutting planes orthogonal to the longitudinal axis of the reactor pressure vessel in the horizontal direction and parallel to the longitudinal axis direction. Cutting device, and a supporting device disposed at a lower part in the axial direction of the reactor pressure vessel and supporting a mirror portion of the pressure vessel from below, and the supporting devices are controlled so as to balance each other. Since the disassembly assisting device for dismantling the reactor pressure vessel is configured as a parallel link mechanism consisting of more than one set of piston and cylinder devices, a plurality of sets that are orthogonal to the longitudinal axis of the pressure vessel in the horizontal direction and parallel to the longitudinal axis direction When cutting the cut surface from the lower cut surface to the upper cut surface, the cut pieces separated from the reactor pressure vessel at the cut surface after cutting are adjusted and controlled in parallelism by the parallel link mechanism. Supported in place, and It is piled up sequentially from top to bottom without losing its position, keeping the horizontal level, without slipping or slipping on the cut surface, greatly improving work safety and stability, beneficial Thus, it is possible to obtain a highly feasible cutting assist device for dismantling a reactor pressure vessel.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram schematically illustrating an outline of a disassembly assisting device for dismantling a reactor pressure vessel according to an embodiment of the present invention.
FIG. 2 is an explanatory view conceptually illustrating a cutting device used directly for cutting in the present embodiment.
FIG. 3 is an explanatory view showing in detail a disassembly cutting assist device including a support lifter schematically shown in FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pressure container 1a Mirror part 2 Cutting line 2a Chip 3 Support lifter 4 Installation space 6 Lower space 8 Partition wall 10 Upper gantry 11 Hoist 12 Cover 13 Support base 14 Clamp 15 Cutting blade 16 Rotating motor 17 Elevating motor 18 Diameter feed motor 19 Main Drive motor 31 Cradle 32 Support section 33 Hopper 34 Chip discharge pipe 35 Vibration device 36 Parallel link 37 Moving wheel

Claims (1)

A cutting device that is orthogonal to the longitudinal axis of the reactor pressure vessel in the horizontal direction, moves along a plurality of cutting planes parallel to the longitudinal axis direction, and cuts the reactor pressure vessel from the inside, and the reactor pressure vessel And a support device for supporting the mirror portion of the pressure vessel from below, wherein the support device comprises three or more sets of piston and cylinder devices controlled to balance each other. A cutting assist device for dismantling a reactor pressure vessel, comprising a link mechanism.

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