JP3861143B2 - Cutting aid for dismantling reactor pressure vessel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nuclear reactor pressure vessel disassembly cutting assistance device that is used when cutting a nuclear reactor pressure vessel that is used as a central device of the nuclear power plant when the nuclear plant is dismantled.
[0002]
[Prior art]
The nuclear power plant developed as a typical example of the peaceful use of nuclear power has been in commercial use in Japan for over 30 years and less than 40 years (Japan Nuclear Power Generation Tokai Power Station: 1966) (Commercial operation started in July), and there are few examples where the operation was terminated during this period, and since a certain cooling period is required after the operation for dismantling, there are no examples of actual dismantling yet.
[0003]
However, in Europe and the United States, which precedes Japan in this field, examples of dismantling have begun to appear. Especially, as a treatment of pressure vessels that hit heavy structures, concrete is filled inside the pressure vessels and then buried deep underground. A method, or a method of cutting the same pressure vessel into a plurality of pieces and then embedding it in the ground in the same manner as described above.
[0004]
Among these methods, when seeing the cutting process, a turntable is installed at the bottom of the pressure vessel extending vertically, and at the side space position of the pressure vessel installed upright. The pressure vessel is arranged according to the image of a cutting device in which a cutting device is arranged, the cutting device is operated from a side circumferential surface while the pressure vessel is rotated by a turntable, and the workpiece is cut from the circumferential surface of the workpiece rotating around the vertical axis. Is cut along a horizontal plane perpendicular to its longitudinal axis.
[0005]
Further, as another cutting processing method, an arc cutting device or a plasma cutting device is taken in and installed in a pressure vessel standing and extending in the vertical direction, and these cutting devices are installed in the vertical direction of the pressure vessel. Some of them are moved along the inner peripheral surface of the same pressure vessel on a horizontal plane perpendicular to the axis, and cut into a ring as described above.
[0006]
[Problems to be solved by the invention]
However, among the cutting methods of the pressure vessel that are preceded in Europe and the United States, in the method of cutting while rotating the pressure vessel with a turntable, in order to connect various conduits to the pressure vessel, It is necessary to carry out difficult work in an extremely limited space, in which parts are carried from a narrow space provided in the assembly and a turntable is assembled, and the pressure vessel is installed so as to be supported from the lower surface. Labor, work exposure, and costly preparatory work is required.
[0007]
In addition, 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 from these gases and fumes. Special waste gas treatment equipment for safety, for example, a particulate matter removal filter and a molecular matter removal filter are required. Etc., and the cost is inevitably increased.
[0008]
Under such circumstances, the present invention has a high degree of difficulty in the dismantling process of a pressure vessel, which is expected to be further increased in Japan in the near future. A useful and feasible reactor pressure vessel that is easy and low-cost, instead of directly linked to increased costs, and that can properly support cutting operations and increase the safety and stability of the operations. It is an object of the present invention to provide a cutting assistance device for disassembly.
[0009]
[Means for Solving the Problems]
The present invention has been made to solve the above-described problem, and the reactor pressure vessel moves along a plurality of cutting planes that are orthogonal to the vertical axis of the reactor pressure vessel in the horizontal direction and parallel to the vertical axis direction. A cutting device that cuts the vessel from the inside and a support device that is disposed at the lower portion in the axial direction of the reactor pressure vessel and supports the mirror portion of the pressure vessel from below, and the support device expands and contracts in a bellows shape. And a parallel link mechanism consisting of three or more pairs of piston / cylinder devices that are arranged parallel to each other in the vertical direction on the lifter and that extend and contract in the vertical direction to control the balance with each other. A cutting auxiliary device for dismantling a furnace pressure vessel is provided.
[0010]
That is, according to the present invention, the reactor pressure vessel has a cutting device that moves along the cutting surface and cuts the reactor pressure vessel from the inside, and at the lower part in the axial direction of the reactor pressure vessel. Has a support device for supporting the mirror part of the pressure vessel from below, and this support device is arranged in parallel with the lifter vertically extending in the vertical direction and the lifter extending vertically in the bellows shape. Since it is composed of a parallel link mechanism consisting of three or more piston / cylinder devices that are stretched and controlled to balance each other, it is perpendicular to the vertical axis of the pressure vessel in the horizontal direction and in the same vertical axis direction. When cutting a plurality of parallel cut surfaces from the lower cut surface to the upper one, the cut pieces separated from the reactor pressure vessel at the cut surfaces that have been cut are supported by a lifter and a parallel link mechanism. Dress In adjusting the levelness, which is controlled and supported at a predetermined position, sequentially stacked while keeping the horizontal level without destroying the position to those from those below the upper, slippage or deviation in cut cutting plane The work safety and stability are greatly improved.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is an explanatory view for schematically explaining the outline of a cutting assistance device for dismantling a reactor pressure vessel according to the present embodiment, FIG. 2 is an explanatory view for conceptually explaining a cutting device used directly for cutting, and FIG. FIG. 2 is an explanatory view showing in detail a disassembly cutting assisting device including the support lifter schematically shown in FIG. 1.
[0012]
The so-called light water reactors, which use water (H ₂ O) as a coolant, dominate the commercial reactors, but the light water reactors are further divided into boiling water type and pressurized water type. The
[0013]
Although the boiling water reactor pressure vessel and the pressurized water reactor pressure vessel have the same basic structure in which the reactor pressure vessel is erected with the vertical direction long, the latter is a pressure vessel. In order to circulate the primary coolant outside, the inlet and outlet swells in the shape of a nozzle, and the support part of the pressure vessel can be formed here, but the former is structured to support via a skirt. The support structure will be different.
[0014]
Although there are differences as described above, both may be exposed to the field of dismantling in the near future, and both will require an efficient dismantling technique, but in this embodiment, A pressurized water reactor pressure vessel will be directly targeted, and a boiling water reactor pressure vessel will be described below as an application modification.
[0015]
That is, in the present embodiment, reference numeral 1 denotes a reactor pressure vessel, the lower mirror part 1a is supported by the support lifter 3, and is installed in an installation space 4 surrounded by a partition wall 8 made of concrete or the like. Yes.
[0016]
Here, after the commercial operation for a certain period such as 30 years, for example, after the end of the commercial operation, the pressure vessel 1 is further subjected to a certain cooling period of 5 to 10 years in consideration of the decay period of radioactivity, The fuel rods and control rods are removed, and the pressure vessel 1 itself is shown as an image of the situation of entering the dismantling operation.
[0017]
The pressure vessel 1 is in a state scheduled to be cut into a plurality along a horizontal plane orthogonal to the axis thereof, and a plurality of cutting lines 2 (cutting lines) are provided at the position of the cutting plane where the cutting is scheduled. In the present specification, the cut surface is a generic term for both the surface to be cut and the cut surface.
[0018]
The pressure vessel 1 is supported at its upper portion by an upper end support portion 7 and at its lower portion by a support lifter 3 installed in the lower space 6 by appropriate means.
[0019]
FIG. 2 conceptually shows a cutting device that cuts the pressure vessel 1 along a cutting line 2 with a blade, and reference numeral 10 denotes an upper frame installed on the upper portion of the pressure vessel 1 for this cutting operation. Is a hoist placed on the upper pedestal 10, and the hoist 11 is connected to a support base 13 disposed in the pressure vessel 1 by a rope covered with a cover 12, so that the support base 13 can be moved in the vertical direction. ing.
[0020]
The support 13 rotates a cutting blade 15 that 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, a lifting motor 17 that allows the cutting blade 15 to move up and down, and a radial feed that feeds the cutting blade 15 in the radial direction toward the wall surface of the pressure vessel 1 and performs cutting and cutting on the wall surface. The motor 18 and the like are supported.
[0021]
The support base 13 is formed of a disk-shaped or radial arm-shaped member centered on the axis of the pressure vessel 1, and clamps 14 are provided at three or more positions on the outer circumference circle, preferably at four positions at 90 ° intervals. The position of the support base 13 can be fixed with respect to the pressure vessel 1 so that the level of the cut surface is maintained.
[0022]
FIG. 3 shows details of the support lifter 3 schematically shown in FIG. 1 and a cutting assisting device that includes the support lifter 3 and cooperates during cutting by the cutting device.
That is, the support lifter 3 is configured such that a plurality of arm members are sequentially pin-connected at the end portion, and the parallel link 36 installed on the upper surface by extending and contracting vertically in a bellows shape can be moved up and down.
[0023]
The parallel link 36 is composed of four pairs of pistons and cylinders. One end of each piston / cylinder is connected to the support lifter 3 and the other end is connected to the pedestal 31, and the expansion / contraction state of the piston is detected by a detection device (not shown). The control device (not shown) adjusts the expansion and contraction of the pistons and cylinders to each other so that the cradle 31 is held horizontally.
[0024]
The cradle 31 is provided with an annular support portion 32 at the top end of the cradle 31. The pressure vessel 1 is supported via the support portion 32, so that the cradle 31 is horizontally supported by the parallel link 36 as described above. By controlling the degree, the pressure vessel 1 is also supported while maintaining the level.
[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 the bottom surface of the hopper 33 and applies vibration to the hopper 33. When cutting or cutting the pressure vessel 1, 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 in the lower part, and the support lifter 3 including the cradle 31 is moved to the support position of the pressure vessel 1 for the convenience of setting. After 3 is installed at the scheduled position, the position is not changed by an appropriate locking device.
[0027]
In the present embodiment configured as described above, when the pressure vessel 1 is cut, the support lifter 3 is disposed at the lower portion of 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 cradle 31.
[0028]
Next, as shown in FIG. 2, the cutting device is installed inside the pressure vessel 1, the support base 13 is positioned by the clamp 14 with respect to the planned cutting line 2, and the cutting line 2 is moved by using the lifting motor 17 or the like. The position where the cutting blade 15 fits is determined and the cutting of the pressure vessel 1 is started.
[0029]
The pressure vessel 1 has a thickness of about 100 to 250 mm, and on the other hand, the cutting blade 15 cut by the radial feed motor 18 in the thickness direction, that is, the radial direction of the pressure vessel 1 is about 10 to 20 mm per stroke. Therefore, the cutting blade 15 makes full use of the turning motor 16 in addition to the radial feed motor 18, repeatedly performs cutting in the thickness direction and cutting in the circumferential direction, and cutting proceeds along the cutting line 2. .
[0030]
The cutting lines 2 are respectively scheduled in a plurality of planes that are orthogonal to the vertical axis of the pressure vessel 1 in the horizontal direction and parallel to the vertical axis direction. Are sequentially cut from the one located below.
[0031]
Therefore, the part including the mirror part 1a of the pressure vessel 1 is first cut, and this part is supported by the cradle 31 via the support part 32 and supported by the parallel link 36 while maintaining the level. A predetermined position is held by the lifter 3.
[0032]
Next, cutting is performed along the cutting line 2 scheduled second from the bottom.
The cutting is performed by making full use of the turning motor 16, the lifting / lowering motor 17, the radial feed motor 18 and the main drive motor 19 in the same manner as the cutting line 2 of the part including the mirror part 1a. When the cutting of the line 2 is completed, the cut piece that has been cut in this way is overlapped by its own weight on the first cut piece.
[0033]
At this time, since the first cut piece is kept level by the parallel link 36 as described above, the second cut piece is stably placed thereon, and in this state, the parallel piece 36 further The levelness is adjusted to be maintained, and the levelness is similarly maintained for the third and fourth cut pieces.
[0034]
Thus, according to the present embodiment, the cut pieces sequentially cut from the lower side to the upper side along the predetermined cutting line 2 are sequentially kept from the lower side to the upper side without changing the position and maintaining the level. The safety and stability of the work can be remarkably improved without causing slippage or slippage on the cut surfaces that have been stacked and cut.
[0035]
Note that the cutting in the present embodiment is performed in the air using the cutting blade 15 from the inside of the pressure vessel 1 along the cutting line 2, so that it becomes irrelevant to the generation of cutting gas and fume, and the radioactive material In this way, the pressure vessel can be cut down safely and reliably, and the pressure vessel can be effectively disassembled.
[0036]
Although the present invention has been described with reference to the illustrated embodiment, the present invention is not limited to this embodiment, and it goes without saying that various modifications 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 that are orthogonal to the vertical axis of the reactor pressure vessel in the horizontal direction and parallel to the vertical axis direction. And a support device that is disposed at the lower part in the axial direction of the reactor pressure vessel and supports the mirror portion of the pressure vessel from below, and the support device includes a lifter that vertically expands and contracts in a bellows shape. It consists of a parallel link mechanism consisting of three or more piston-cylinder device which is controlled so as to ensure mutual balance adjusted stretch vertically disposed parallel to each other in the vertical direction on the lifter, thereby reactor pressure Since it constitutes a cutting aid for disassembling the container, it cuts a plurality of cutting surfaces 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 surface to the upper one. When you are finished cutting In cut pieces separated from the reactor pressure vessel, adjusting the levelness with supporting device having the lifter and parallel link mechanism, which is controlled and supported at a predetermined position, without losing the position to those from those below the upper Reactor pressure vessels that are useful and highly feasible, which are stacked one after another in order to maintain the level and improve the safety and stability of work without causing slippage or slippage on the cut surfaces. It is possible to obtain a cutting assist device for dismantling.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram schematically illustrating an outline of a cutting assistance device for dismantling a reactor pressure vessel according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram 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 assistance device including the support lifter schematically shown in FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pressure vessel 1a Mirror part 2 Cutting line 2a Chip 3 Support lifter 4 Installation space 6 Lower space 8 Partition wall 10 Upper mount 11 Hoist 12 Cover 13 Support base 14 Clamp 15 Cutting blade 16 Turning motor 17 Lifting motor 18 Radial feed motor 19 Main Drive motor 31 Receiving base 32 Support section 33 Hopper 34 Chip discharge pipe 35 Exciting device 36 Parallel link 37 Moving wheel

Claims (1)

A cutting device that moves along a plurality of cutting planes that are orthogonal to the vertical axis of the reactor pressure vessel in the horizontal direction and parallel to the vertical axis direction to cut the reactor pressure vessel from the inside, and the reactor pressure vessel And a support device that supports the mirror portion of the pressure vessel from below, and the support device is arranged in a bellows-like manner to vertically expand and contract, and the lifter is arranged in parallel with each other in the vertical direction. A reactor pressure vessel disassembly cutting assistance device comprising a parallel link mechanism composed of three or more sets of piston / cylinder devices that are controlled by adjusting the balance by extending and contracting vertically .

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