JP2004061396A - Cutting apparatus for dismantling reactor pressure vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting apparatus for dismantling a reactor pressure vessel to be used for cutting the reactor pressure vessel, when a nuclear power plant is dismantled or worked likewise, which cuts the vessel easily, safely and stably at a low cost. <P>SOLUTION: The cutting apparatus, disposed in an interior of the reactor pressure vessel for cutting the vessel along a specified horizontal cutting cross-section or a vertical cutting cross-section from an interior, is provided selectively and detachably with a horizontal cutting blade for cutting the horizontal cutting cross-section or a vertical cutting blade for cutting the vertical cutting cross section. The pressure vessel as a heavy structure is selectively cut in round slices, along the horizontal cutting cross-section by a simple constitution or cut along the vertical cutting cross section perpendicular to the horizontal cutting cross-section so that the vessel can be cut into desired shapes. <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 reactor pressure vessel dismantling cutting device used for cutting a reactor pressure vessel used as a central device of the nuclear power plant when dismantling the nuclear power 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 parts from the narrow space provided in the area and assemble the turntable, and to install it so that the pressure vessel is supported from the lower surface, which is a difficult task in a very limited space. , The costs are immense.
[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. Provided is a useful and highly feasible cutting apparatus for dismantling a reactor pressure vessel which can easily and inexpensively cut the pressure vessel safely and stably, instead of directly leading to an increase in cost. It is a subject.
[0009]
[Means for Solving the Problems]
The present invention has been made in order to solve the above-mentioned problems, and as a first means, is installed inside a reactor pressure vessel, and is orthogonal to the longitudinal axis of the reactor pressure vessel in the horizontal direction and the longitudinal axis direction. A plurality of horizontal cutting surfaces parallel to, or a cutting device for cutting the reactor pressure vessel from the inside along a plurality of vertical cutting surfaces extending in the longitudinal direction of the reactor pressure vessel, the cutting device is the said An object of the present invention is to provide a cutting device for dismantling a reactor pressure vessel, wherein a horizontal cutting blade for cutting a horizontal cutting surface and a vertical cutting blade for cutting a vertical cutting surface are selectively detachably attached.
[0010]
That is, according to the first means, the cutting device disposed inside the reactor pressure vessel and cutting the pressure vessel from the inside along a predetermined horizontal cutting surface or a vertical cutting surface is the horizontal cutting device. Since the horizontal cutting blade for surface cutting or the vertical cutting blade for vertical cutting surface cutting can be selectively attached and detached, the pressure vessel of the heavy structure can be cut into a circular section along the horizontal cutting surface under a simple configuration. Cutting and cutting along the vertical cutting plane perpendicular to the horizontal cutting plane are appropriately selected and combined, and the pressure vessel is cut into a desired shape to enable efficient dismantling processing. It is.
[0011]
According to a second aspect of the present invention, in the first aspect, the cutting device for dismantling a reactor pressure vessel, wherein the horizontal cutting blade and the vertical cutting blade are each formed of a hard coating blade such as a carbide or a nitride. Is provided.
[0012]
That is, according to the second means, the pressure vessel is disposed inside the reactor pressure vessel, and the pressure vessel is employed in a cutting device that cuts the pressure vessel from the inside along a predetermined horizontal cutting plane or a vertical cutting plane. Since the horizontal cutting blade that cuts the container along the horizontal cutting surface and the vertical cutting blade that cuts along the vertical cutting surface are each made of a hard coating blade such as carbide or nitride, it has excellent heat resistance, The use of high-strength coated blades eliminates the need for additional blade cooling equipment during cutting work, and greatly reduces the need to replace blades during cutting, resulting in high stability and safety. Thus, a cutting device suitable for use in this kind of dismantling operation is obtained.
[0013]
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 a reactor pressure vessel to be cut using the reactor pressure vessel cutting apparatus according to the present embodiment, and FIG. 2 shows an outline of a reactor pressure vessel cutting apparatus. FIG.
[0014]
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.
[0015]
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 outside, the inlet / outlet swells like a nozzle and a support portion of the pressure vessel can be formed here. However, the latter has a difference in the support structure in the absence of this.
[0016]
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 boiling water reactor pressure vessel will be described directly as a target, and a pressurized water reactor pressure vessel will be described below as being applicable as an applied modification thereof.
[0017]
That is, in the present embodiment, reference numeral 1 denotes a pressure vessel of a nuclear reactor, in which the lower mirror 1a is supported by the support skirt 5 at a position above the lower space 6, and the periphery is surrounded by a partition wall 8 made of concrete or the like. It is installed in the space 4.
[0018]
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 rods, the device for controlling the fuel rods, and the like are removed, and the situation in which the pressure vessel 1 itself starts to be dismantled is shown as an image.
[0019]
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.)
[0020]
FIG. 2 shows a cutting device for cutting the pressure vessel 1 along a cutting line 2. Reference numeral 10 denotes an upper pedestal installed on the upper part of the pressure vessel 1 for this cutting operation, and 11 denotes an upper pedestal 10. With the hoist placed, the hoist 11 is connected to a support 13 arranged in the pressure vessel 1 by a cable covered with a cover 12 to enable the support 13 to move up and down.
[0021]
The support base 13 is composed of four arm members extending radially at 90 ° intervals around the axis of the pressure vessel 1 (a disk-shaped member in which the four arm members are integrated on the same plane). ), And clamps 14 are provided at four positions of the support base 13 at the tip of each arm-shaped member.
[0022]
Therefore, the support base 13 is raised and lowered by the hoist 11, and the four clamps 14 are actuated at predetermined positions in the vertical direction of the pressure vessel 1 so that the support base 13 is fixedly stopped at a desired position inside the pressure vessel 1, The levelness with respect to the cut surface 2 can be maintained.
[0023]
Further, the support table 13 includes a side cutter 15 that rotates and cuts the wall surface of the pressure vessel 1 along the horizontal cutting plane, a main drive motor 19 that rotationally drives the side cutter 15, A turning motor 16 for moving the side cutter 15 along the surface, an elevating motor 17 for moving the side cutter 15 up and down to adjust the position with respect to the cut surface 2, and the side cutter 15 on the wall surface of the pressure vessel 1. A radial feed motor 18 that feeds radially toward and cuts and cuts the same wall surface, and an end mill that can cut the wall surface of the pressure vessel 1 along a vertical cutting surface parallel to the axis instead of the side cutter 15 is attached. It supports an end mill mounting portion 20 and the like that can be used.
[0024]
In the present embodiment, the end mill is attached to the end mill independently of the attachment portion of the side cutter 15, and the end mill attachment portion 20 for attaching the end mill is provided. By adjusting the mounting directions of the respective rotating shafts, the mounting portions can be made common, and mounting and dismounting can be performed alternately to replace the blade.
[0025]
The pressure vessel 1 has a thickness of about 100 to 250 mm. On the other hand, the cut of the side cutter 15 cut in the thickness direction by the radial feed motor 18, that is, in the radial direction of the pressure vessel 1, is not practical. Since the stroke is about 10 to 20 mm per stroke, the side cutter 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 a plurality of times. The ring-shaped cutting of the pressure vessel 1 proceeds along the horizontal cutting plane indicated by the line 2.
[0026]
On the other hand, the end mill is capable of cutting about 30 to 50 mm per stroke for practical use. Therefore, the cutting depth along the so-called vertical cutting plane in the direction parallel to the axis of the pressure vessel 1 is about 30 to 50 mm. When the length exceeds the above, cutting is performed along the same vertical cutting surface in a plurality of times.
[0027]
Further, in the present embodiment, the end mill attached to the side cutter 15 and the end mill attachment portion 20 employs a so-called coated blade coated with a titanium alloy.
[0028]
In the present embodiment configured as described above, when cutting along the horizontal cutting plane, the cutting device is installed inside the pressure vessel 1 and supported by the clamp 14 on the predetermined cutting line 2. The position of the table 13 is determined, the position of the side cutter 15 of the horizontal cutting blade, which cuts along the cutting line 2 using the elevating motor 17 or the like, is determined so as to conform to the horizontal cutting surface, and cutting of the pressure vessel 1 is started.
[0029]
As described above, the pressure vessel 1 of the heavy-weight structure has a thickness of about 100 to 250 mm, while the cut of the side cutter 15 cut in the thickness direction by the radial feed motor 18, that is, in the radial direction of the pressure vessel 1, Since the stroke is about 10 to 20 mm per stroke, the side cutter 15 repeatedly performs cutting in the thickness direction and cutting in the circumferential direction by making full use of the diameter feed motor 18 and the turning motor 16, and along the cutting line 2. The cutting proceeds.
[0030]
The cutting line 2 is orthogonal to the longitudinal axis of the pressure vessel 1 in the horizontal direction, and a plurality of cutting lines 2 that are parallel to the longitudinal axis direction are scheduled. The cut is made from what is scheduled below.
[0031]
Next, the cutting is performed along the second predetermined cutting line 2 from the bottom in the same procedure as described above, and thereafter the third and fourth steps are similarly performed, and the pressure vessel 1 is cut in a ring shape.
[0032]
On the other hand, although not shown, when cutting along a predetermined vertical cutting surface extending in a direction perpendicular to the cutting line 2 serving as the horizontal cutting surface, the end mill mounting portion 20 is used instead of the side cutter 15. And vertical cutting can be performed while moving the end mill by the elevating motor 17.
[0033]
In addition, since the stroke of the end mill is practically about 30 to 50 mm as described above, when the distance of this vertical cut surface exceeds 30 to 50 mm, the support table 13 for supporting the lifting motor 17 is not used. The set position is adjusted, and the vertical cutting is performed by repeating the cutting a plurality of times.
[0034]
This vertical cutting is preferably performed in combination with the cutting of the horizontal cutting surface by the side cutter 15 as a result. As a result, the cutting piece cut into a ring shape by the horizontal cutting is divided into a plurality of pieces in the circumferential direction, Can be easily handled.
[0035]
Thus, according to the present embodiment, the cut pieces are sequentially cut in a ring shape from below along a predetermined cutting line 2 and, if necessary, are vertically cut along the axial direction to obtain a circumference of the ring cut. The cutting pieces divided into multiple parts in the direction are cut off in the air by a cutting blade, so they are independent of the generation of cutting gas and fume, there is no scattering or diffusion of radioactive materials, cost is simple equipment The pressure vessel has been kept low, and safe and reliable cutting has been performed, and the pressure vessel has been effectively dismantled.
[0036]
In addition, the side cutter 15 and the end mill, which directly participate in the cutting, employ a coating cutter to perform the coating for the special work of dismantling the pressure vessel 1 having a thick structure and a heavy structure in a narrow working space. The heat resistance and high strength properties of the blades are synergistically utilized, eliminating the need for a blade cooling facility during cutting work, and eliminating the need for blade replacement during the cutting work. As a result, a suitable cutting device was obtained.
[0037]
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.
[0038]
【The invention's effect】
As described above, according to the invention described in claim 1 of the present application, a plurality of horizontal axes which are installed inside the reactor pressure vessel and are orthogonal to the longitudinal axis of the reactor pressure vessel in the horizontal direction and parallel to the longitudinal axis direction. A cutting device for cutting the reactor pressure vessel from the inside along a cut surface, or a plurality of vertical cut surfaces extending in the longitudinal direction of the reactor pressure vessel, the cutting device cutting the transverse cut surface Since the horizontal cutting blade and the vertical cutting blade for cutting the vertical cutting surface are selectively detachable, the cutting device for dismantling the reactor pressure vessel is configured. The cutting of the same pressure vessel into a desired shape is performed by appropriately selecting and combining the cutting along the horizontal cutting plane and the cutting along the vertical cutting plane perpendicular to the horizontal cutting plane, and disassembling efficiently. It is possible to obtain a suitable cutting apparatus for dismantling a reactor pressure vessel for performing a treatment.
[0039]
According to a second aspect of the present invention, in the first aspect of the present invention, the horizontal cutting blade and the vertical cutting blade are respectively disassembled as a hard coating blade such as carbide or nitride. This pressure vessel is arranged in a reactor pressure vessel, and is employed in a cutting apparatus that cuts the pressure vessel from the inside along a predetermined horizontal cutting plane or a vertical cutting plane. Cutting blade along the horizontal cutting surface, and vertical cutting blade along the vertical cutting surface are coated with high heat resistance and high strength. It is not necessary to provide a cutting device, and the need for blade replacement during cutting work is greatly reduced, providing a stable and safe cutting device suitable for use in this kind of demolition work. Was able to do Than it is.
[Brief description of the drawings]
FIG. 1 is an explanatory view schematically illustrating a reactor pressure vessel scheduled to be cut using a reactor pressure vessel cutting device according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing an outline of a cutting device for a reactor pressure vessel.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pressure vessel 1a Mirror part 2 Cutting line 4 Installation space 5 Support skirt 6 Lower space 8 Partition wall 10 Upper frame 11 Hoist 12 Cover 13 Support base 14 Clamp 15 Side cutter 16 Rotation motor 17 Elevating motor 18 Diameter feed motor 19 Main drive motor 20 End mill mounting part 20

Claims (2)

Installed inside the reactor pressure vessel, a plurality of horizontal cross sections perpendicular to the longitudinal axis of the reactor pressure vessel in the horizontal direction and parallel to the longitudinal axis direction, or a plurality of cross sections extending in the longitudinal axis direction of the reactor pressure vessel A cutting device that cuts the reactor pressure vessel from the inside along the vertical cutting surface, and the cutting device selects a horizontal cutting blade that cuts the horizontal cutting surface and a vertical cutting blade that cuts the vertical cutting surface A cutting device for dismantling a reactor pressure vessel, wherein the cutting device is configured so as to be detachable. The cutting device for dismantling a reactor pressure vessel according to claim 1, wherein the horizontal cutting blade and the vertical cutting blade are each formed of a hard coating blade such as a carbide or a nitride.

Images