JP6979780B2 - Reactor building demolition method and equipment - Google Patents

Description

The present invention relates to a method and an apparatus for dismantling a reactor building provided with a reactor heat shield wall surrounding a reactor pressure vessel.

FIG. 10 is a schematic cross-sectional view of the main part of the reactor building. As shown in the figure, the reactor containment vessel 2 is arranged inside the reactor building 1. The reactor pressure vessel 3 is housed in the reactor containment vessel 2. A reactor heat shield wall 4 is formed around the reactor pressure vessel 3. The upper part of the reactor building 1 is an operation area 5, and an overhead crane 6 is movably attached in the area.
Such nuclear power generation facilities are generally decommissioned after the end of their useful life, and are therefore dismantled and removed. At this time, it is necessary to prevent the workers engaged in the dismantling work from being exposed to radiation and dismantle the radioactive materials so as not to scatter them to the outside.

The dismantling method disclosed in Patent Document 1 is to insert a cutting means into the inside of the reactor pressure vessel from the upper opening of the reactor pressure vessel, cut the vessel from the inside, and carry out the cut reactor pressure vessel to the outside. is doing.

Japanese Unexamined Patent Publication No. 2004-61396

As disclosed in Patent Document 1, when cutting a reactor pressure vessel, a work space can be secured by using the internal space of the vessel. At this time, a mechanism for gripping the reaction force of the mechanical cutting is required, and the installation space of this mechanism can be easily secured.
On the other hand, if the reactor pressure vessel can be cut from the outside, the options for the dismantling method can be expanded while reducing the exposure and scattering of radioactive materials.
However, in the current reactor pressure vessel, the space between the reactor pressure vessel and the reactor heat shield wall is narrow, and it is difficult to arrange cutting means in a narrow space to cut from the outside, and the dismantling method is extremely limited. It was.

Therefore, in view of the above-mentioned problems of the prior art, it is an object of the present invention to provide a reactor building dismantling method and an apparatus capable of expanding the options of the reactor pressure vessel dismantling method.

As a first means for solving the above-mentioned problems, the present invention includes a first step of disassembling the internal structure of the reactor pressure vessel and the first step.
The second step of removing the connecting pipe of the reactor pressure vessel and
A wire saw of a cutting means is wound around the outer periphery of the reactor heat shield wall in which the reactor pressure vessel is arranged inside the wall to cut the reactor into round slices, and a hanging bracket is attached to the cut reactor heat shield wall to form a reactor containment vessel. The third step of lifting the reactor heat shield wall cut by connecting the hanging bracket to the hanging means of the balance suspended by the overhead crane of the reactor building from the upper surface opening of the reactor building and carrying it out for dismantling. When,
The fourth step of dismantling the reactor pressure vessel and
A fifth step of dismantling the reactor containment vessel,
Have a, the third step includes: the cutting means frame, said wire saw for slicing said reactor heat shielding wall on said platform, said reactor building has a main pulley winding the wire saw It is provided with a drive unit arranged in the operation area of the above, and is characterized in that the gantry and the drive unit are cut while being swiveled along the outer periphery of the reactor heat shield wall around the reactor pressure vessel in the middle of cutting. The purpose is to provide a method for dismantling the reactor building.
According to the first means, the reactor heat shield wall can be dismantled and removed before the reactor pressure vessel, so that the options for the dismantling method can be easily expanded by cutting the reactor pressure vessel from the outside. Can be done.

As a second means for solving the above-mentioned problems, the present invention relates to the above-mentioned first means, in which the third step is described.
The cutting step of winding the wire saw of the cutting means around the outer circumference of the reactor heat shielding wall and cutting it into round slices.
The installation process of attaching the hanging bracket to the cut reactor heat shield wall,
A carry-out step of lifting the reactor heat shield wall cut by connecting the hanging bracket to the hanging means of the balance suspended by the overhead crane of the reactor building from the upper surface opening of the reactor containment vessel. When,
It is to provide a method of dismantling a reactor building characterized by having.
According to the second means, the reactor pressure vessel can be cut from the outside of the reactor heat shield wall and disassembled while the reactor pressure vessel is left inside the wall. The shield wall cut into round slices is placed on the upper end of the shield wall, and there is no risk of falling.

As a third means for solving the above-mentioned problems, in the above-mentioned second means, in the cutting step, the cutting means is placed around the reactor pressure vessel on the outer periphery of the reactor heat shield wall. The purpose of the present invention is to provide a method for dismantling a reactor building, which is characterized by turning along the reactor building.
According to the third means, the cutting step can be efficiently sliced along a substantially horizontal direction.

As a fourth means for solving the above problems, the present invention is provided with a surface facing the upper end surface of the reactor heat shield wall, and can be inserted from the upper surface opening of the reactor containment vessel by an overhead crane in the reactor building. With a balance,
A gantry that is placed between the reactor containment vessel and the reactor heat shield wall and can run on the temporary scaffold of the reactor containment vessel or be hung by the balance, and the reactor heat shield wall on the gantry. It has a wire saw that slices the wire saw and a drive unit that has a main pulley around which the wire saw is wound and is arranged in the operation area of the reactor building. A cutting means that enables turning along the outer circumference of the reactor,
A hanging means that can hang a hanging bracket attached to the upper end surface of the reactor heat shield wall that has been sliced into round slices.
The purpose is to provide a demolition device for a reactor building, which is characterized by being equipped with.
According to the fourth means, the reactor pressure vessel can be cut from the outside of the reactor heat shield wall and disassembled while the reactor pressure vessel is left inside the wall. The shield wall cut into round slices is placed on the upper end of the shield wall, and there is no risk of falling.

According to the present invention, the reactor heat shield wall can be dismantled and removed before the reactor pressure vessel, and the options for the dismantling method of the reactor pressure vessel can be expanded. Further, the space between the reactor containment vessel and the reactor heat shield wall is small, and the reactor pressure vessel can be left inside the wall and can be disassembled by cutting from the outside of the reactor heat shield wall. ..

It is a processing flow diagram of the dismantling method of the reactor building of this invention. It is a structural schematic diagram of the dismantling apparatus of the reactor building of this invention. It is a plan view of the balance. It is a top view of the balance of the modification. It is explanatory drawing of the cutting means. It is explanatory drawing of the modification 1 of the cutting means. It is explanatory drawing of the modification 2 of the cutting means. It is explanatory drawing of the dismantling method of the reactor building of this invention. It is a block diagram of the structure of the demolition equipment of the reactor building of the modified example. It is a schematic sectional view of the main part of a reactor building.

The method of dismantling the reactor building and the embodiment of the apparatus of the present invention will be described in detail below with reference to the accompanying drawings.

[Reactor building demolition device 10]
The reactor building dismantling device 10 of the present invention is a reactor building in which a reactor heat shielding wall is arranged outside the reactor pressure vessel, and the reactor heat is left in the wall while the reactor pressure vessel 3 is left. It is a device capable of disassembling the shielding wall 4. FIG. 2 is a schematic configuration diagram of the dismantling device of the reactor building of the present invention. As shown in the figure, the dismantling device 10 of the reactor building of the present invention mainly includes a balance 20, a cutting means 40, and a hanging means 60.

[Balance 20]
FIG. 3 is a plan view of the balance. The balance 20 has a cylindrical shape having substantially the same shape as the reactor heat shield wall 4 in a plan view, has a surface facing the upper end surface of the reactor heat shield wall 4, and can be inserted from the upper surface opening 2a of the reactor containment vessel 2. It is formed to the size. The balance 20 has a hanging metal fitting that engages with the chain of the overhead crane 6 attached to the upper surface thereof, and has a plurality of hanging means 60 described later on the lower surface thereof. Further, the balance 20 is configured to be able to turn while being suspended by the overhead crane 6 by the turning means 6a attached to the connection point with the overhead crane 6. Such a balance 20 can carry the cutting means 40, which will be described later, into the vicinity of the reactor heat shield wall 4, and carry out the reactor heat shield wall 4 cut into round slices to the outside.

In addition, the shape of the balance 20 can be formed into a cross shape in a plan view, for example, if a part of the surface facing the upper end surface of the reactor heat shielding wall 4 is provided as shown in FIG. The cross-shaped balance 20A has hanging means 60 attached to four ends facing the reactor heat shield wall 4.

[Cutting means 40]
FIG. 5 is an explanatory view of the cutting means, and is a plan view in which a wire saw is wound around the outer periphery of the reactor heat shield wall 4. The cutting means 40 mainly includes a gantry 42, a drive unit 401 (see FIG. 2), a wire saw 48, and a guide 50.
The gantry 42 has a pair of horizontal pulleys 44a and b in which the rotation axes are arranged along the vertical direction and a pair of vertical pulleys 46a and b in which the rotation axes are arranged in the horizontal direction are mounted on the table. The horizontal pulleys 44a and b are attached to the reactor heat shielding wall 4 side, and the vertical pulleys 46a and b are attached to the reactor containment vessel 2 side. A drive unit 401 is provided above the horizontal and vertical pulleys 44 and 46. The drive unit is arranged in the operation area 5 and includes a main pulley directly connected to the drive motor, a plurality of auxiliary pulleys, and an extra length winding mechanism. Further, the horizontal pulleys 44a and 44 shown in FIG. 5 have a tension adjusting mechanism. The specific configuration of the tension adjusting mechanism is a pair of cylinder rods that can expand and contract the horizontal pulleys 44a and 44 in the direction of approaching or separating from each other. When the horizontal pulleys 44a and 44b having such a configuration are brought close to each other by the tension adjusting mechanism, the tension (deflection) of the wire saw described later can be eliminated and the reactor heat shield wall can be cut.

The wire saw 48 is a wire rope for cutting in a loop shape that is longer than the outer circumference of the reactor heat shield wall 4. The wire saw 48 is wound around the horizontal and vertical pulleys 44a, b, 46a, b and the main pulley and auxiliary pulley of the drive unit 401.
The guide 50 positions the wire saw wound around the reactor heat shield wall 4. As a specific configuration of the guide 50, for example, a pair of upper and lower anchors can be mounted by driving them into a shielding wall surface with a wire saw sandwiched between them. A plurality of such guides 50 can be attached radially from the central reactor pressure vessel 3 along the outer periphery of the reactor heat shield wall 4, and the wire saw can be wound in a substantially horizontal direction.
The cutting means 40 of the present embodiment is configured such that the drive unit 401 is arranged in the operation area 5, a hanging metal fitting is attached on the gantry 42, and the balance 20 can be hung from the hanging means. Further, the cutting means 40 can be configured to freely travel on a flat surface by attaching wheels to the lower surface. The cutting means 40 may be provided with either one or both of the hanging metal fittings and the wheels.

When cutting using the temporary scaffolding inside the reactor containment vessel 2, the cutting means 40 is provided with wheels so that it can travel freely on the temporary scaffolding. If there is no temporary scaffolding inside the reactor containment vessel 2, a hanging bracket can be attached to the gantry 42 and attached to the balance 20 or hung via a hanging means 60 described later.
FIG. 6 is an explanatory diagram of a modified example 1 of the cutting means. The cutting means 40a of the first modification has a tension adjusting mechanism 52 and a mobile drive pulley on the drive unit 401 side installed in the operation area 5, in addition to the configuration of the horizontal and vertical pulleys 44a, b, 44a, b on the gantry 42. It is equipped with 54. The tension adjusting mechanism 52 cancels the tension of the wire saw as described above, and has a configuration in which a pair of fixed pulleys 52a and a moving pulley 52b are provided between the vertical pulleys 46a and b and the drive unit. The tension adjusting mechanism 52 having such a configuration is configured so that the moving pulleys 52b can move forward and backward so as to approach or separate from each other, and by approaching each other, the tension of the wire saw can be released.

The mobile drive pulley 54 includes a drive motor 54a, a drive pulley 54b connected to the shaft of the drive motor 54a, and a slide portion capable of sliding the drive motor 54a and the drive pulley 54b in a direction orthogonal to the axis of the shaft. There is.
The cutting means 40a of the modified example 1 having such a configuration can release the tension of the wire saw by the tension adjusting mechanism 52, absorb and eliminate the excess length of the wire saw by the mobile drive pulley 54, and at the same time, reduce the tension required for cutting. Can be maintained.

FIG. 7 is an explanatory diagram of a modification 2 of the cutting means. The cutting means 40b of the second modification has a tension adjusting mechanism 52 and a drive pulley 55 on the drive unit 401 side installed in the operation area 5, in addition to the configuration of the horizontal and vertical pulleys 44a, b, 44a, b on the gantry 42. And the extra length adjusting mechanism 56 is provided.
The tension adjusting mechanism 52 cancels the tension of the wire saw as described above, and has a configuration in which a pair of fixed pulleys 52a and a moving pulley 52b are provided between the vertical pulleys 46a and b and the drive pulley 55. The tension adjusting mechanism 52 having such a configuration is configured so that the moving pulleys 52b can move forward and backward so as to approach or separate from each other, and by approaching each other, the tension of the wire saw can be released.
The drive pulley 55 is a pulley that moves around by sandwiching a wire saw between a pair of pulleys.

The extra length adjusting mechanism 56 winds a spirally wound wire saw around a plurality of pulleys 56a arranged in a circumferential shape. Further, the plurality of pulleys 56a are attached to the slide portion 56b which can move in the direction orthogonal to the axis and in the direction of approaching or separating from each other. The extra length adjusting mechanism 56 having such a configuration can absorb and eliminate the extra length of the wire saw, and at the same time, maintain the tension required for cutting.

[Hanging means 60]
The hanging means 60 is a chain block attached to the balance 20 in plurality. As an example, four suspending means 60 of the present embodiment are attached on a straight line passing through the center of the balance 20 and orthogonal to each other.
In such a hanging means 60, the reactor heat shield wall 4 cut in a circle by the cutting means 40 is hung and moved to an arbitrary position in the vertical direction, or the gantry 42 of the cutting means 40 is hung and arbitrarily in the vertical direction. You can move it to a place.

[How to dismantle the reactor building]
Next, the method of dismantling the reactor building of the present invention will be described below.
FIG. 1 is a processing flow diagram of a method for dismantling a reactor building of the present invention.
The internal structure of the reactor pressure vessel is dismantled (first step: step 1). The support structure and the like for arranging the atomic fuel in the reactor pressure vessel 3 are dismantled and removed.
The connection pipe connected to the reactor pressure vessel is removed (second step: step 2).

The reactor heat shield wall in which the reactor pressure vessel is arranged inside the wall is dismantled (third step: step 3). FIG. 8 is an explanatory diagram of a method of dismantling the reactor building of the present invention.
As shown in FIG. 6A, the drive unit 401 of the cutting means 40 is arranged in the operation area 5. Then, the balance 20 in which the gantry 42 and the wire saw 48 are suspended from the upper surface opening 2a of the reactor containment vessel 2 via the suspending means 60 is suspended by the overhead crane 6 of the reactor building 1 (carrying step).

The gantry 42 and the wire saw 48 are installed on the temporary scaffolding 2b near the cut portion of the reactor heat shielding wall 4, and are removed from the hanging means 60. The temporary scaffold 2b is formed in a cylindrical shape in a plan view so as to surround the outer periphery of the cylindrical reactor heat shield wall 4. Further, the temporary scaffolding 2b is detachably formed on the wall surface of the reactor containment vessel 2 for cutting the reactor heat shielding wall 4 into round slices.

As shown in FIG. 3B, the loop-shaped wire saw 48 is wound around the outer periphery of the reactor heat shield wall 4 via a guide. After fixing the gantry 42 that receives the cutting reaction force on the temporary scaffolding 2b, the main loop of the drive unit 401 of the operation area 5 is rotated to cut the reactor heat shield wall 4 into round slices (cutting step).
As shown in FIG. 5, it is difficult to evenly maintain the contact force between the wire saw and the shielding wall when cutting in a circle with a wire saw wound around the reactor heat shielding wall 4, and a portion where the cutting progress is large appears. In this case, the drive unit 401 is stopped during any cutting such as cutting a thickness of several tens of centimeters from the outer periphery of the reactor heat shield wall 4, and the cutting means 40 is mounted along the outer periphery of the reactor heat shield wall 4. Turn and move the 42 together on the temporary scaffolding 2b.
Then, the main loop of the drive unit 401 is rotated to cut the reactor heat shield wall 4 into round slices again.

By cutting by the cutting means 40 and shifting the position of the gantry 42 so as to rotate along the outer circumference several times, the reactor heat shield wall 4 can be cut into round slices in a substantially horizontal direction.
As shown in FIG. 6C, the hanging metal fitting 62 is attached to the reactor heat shield wall 4 cut into round slices (installation process). In the present embodiment, the hanging metal fitting 62 is attached to the upper end surface of the reactor heat shielding wall 4 at a position facing the hanging means 60.

As shown in FIG. 3D, after the hanging means 60 is locked to the hanging metal fitting 62, the reactor heat shield wall 4 cut into round slices is lifted together with the balance 20 by the overhead crane 6 and carried out (carrying step). ).
After the reactor heat shield wall 4 cut into round slices is carried out, the temporary scaffolding 2b is moved downward and the carry-in step to the carry-out process is repeated again to dismantle the reactor heat shield wall 4.

In the above dismantling method, the work of installing the cutting means 40 on the temporary scaffolding 2b of the reactor containment vessel 2 and moving the cutting means 40 on the temporary scaffolding 2b to perform the cutting step has been described. Next, the case where there is no temporary scaffolding for the reactor containment vessel 2 will be described below.
FIG. 9 is a schematic configuration diagram of the dismantling device of the reactor building of the modified example. A tensioning means 70 is attached to the balance 20 in order to receive the cutting reaction force generated when the shielding wall is cut, and the cutting means 40B (a set including the drive unit and the gantry) is fixed to the balance 20 via the connecting means 80. ..

In the tensioning means 70, the main body is fixed to the balance 20, and the tip of the rod that expands and contracts from the main body is in contact with the wall surface of the reactor containment vessel 2. A plurality of such main bodies can be provided on the outer periphery of the balance 20 and fixed at a predetermined position of the reactor containment vessel 2.
The connecting means 80 has a predetermined rigidity, and is a connecting member having one end fixed to the balance 20 and the other end fixed to the cutting means 40B.
The method of dismantling the reactor building using the reactor building dismantling device of such a modified example is basically the same as the processing flow shown in FIG. 1, but the carrying-in process and the cutting process shown below are different.

In the carry-in process, the cutting means 40B fixed by the connecting member 80 and the wire saw 48 suspended by the hanging means 60 using the balance 20 from the upper surface opening 2a of the reactor containment vessel 2 are carried by the overhead crane 6 of the reactor building 1. Suspend. Next, the balance 20 is fixed to the reactor containment vessel 2 by the tensioning means 70.
The main loop of the drive unit is rotated to cut the reactor heat shield wall 4 into round slices (cutting step). The main loop of the drive unit 401 is stopped during any cutting such as cutting a thickness of several tens of centimeters from the outer periphery of the reactor heat shielding wall 4 with the wire saw 48. When the cutting means 40B is moved along the outer periphery of the reactor heat shield wall 4, the fixing by the tensioning means 70 is released and the balance 20 is swiveled by the swirling means 6a.
Then, the main loop of the drive unit is rotated to cut the reactor heat shield wall 4 into round slices again.

By performing such cutting by the cutting means 40B and shifting the position of the cutting means 40B by turning the balance 20 along the outer circumference several times, the reactor heat shielding wall 4 is cut into round slices in a substantially horizontal direction. Can be done.
The installation process and the carry-out process are performed in the same manner.

After dismantling the reactor heat shield wall, the reactor pressure vessel is dismantled (4th step: step 4). Since the outer reactor heat shield wall 4 of the reactor pressure vessel 3 has been dismantled and removed, a cutting means is installed on the outside in addition to the method of arranging the cutting means on the inside and cutting as in the conventional method. There is space for cutting, and the options for cutting methods are expanding.

The reactor containment vessel is dismantled (fifth step: step 5).
According to the method of dismantling the reactor building of the present invention, the reactor heat shield wall can be sliced and cut even when the reactor pressure vessel is installed inside the wall. The shield wall cut into round slices is placed on the upper end of the shield wall, and there is no risk of falling.

INDUSTRIAL APPLICABILITY The present invention is particularly useful in the construction field requiring round-cutting work of a cylindrical structure such as a nuclear reactor heat shield wall and a chimney.

1 ………… Reactor building, 2 ………… Reactor storage vessel, 2a ………… Top opening, 2b ………… Temporary scaffolding, 3 ………… Reactor pressure vessel, 4 ………… Reactor heat shield wall, 5 ………… Operation area, 6 ………… Overhead crane, 10 ………… Reactor building dismantling device, 20 ………… Balance, 22 ………… Hanging metal fittings, 40 ………… Cutting means, 42 ………… Stand , 44a, b ……… Horizontal pulley, 46a, b ……… Vertical pulley, 48 ……… Wire saw, 50 ……… Guide, 52 ……… Tension adjustment mechanism, 54 ……… Mobile drive pulley, 55… …… Drive pulley, 56 ………… Extra length adjustment mechanism, 60 ………… Hanging means, 62 ………… Hanging metal fittings, 70 ………… Stretching means, 80 ………… Connecting means.

Claims (2)

The first step of dismantling the internal structure of the reactor pressure vessel,
The second step of removing the connecting pipe of the reactor pressure vessel and
A wire saw of a cutting means is wound around the outer periphery of the reactor heat shield wall in which the reactor pressure vessel is arranged inside the wall to cut the reactor into round slices, and a hanging bracket is attached to the cut reactor heat shield wall to form a reactor containment vessel. The third step of lifting the reactor heat shield wall cut by connecting the hanging bracket to the hanging means of the balance suspended by the overhead crane of the reactor building from the upper surface opening of the reactor building and carrying it out for dismantling. When,
The fourth step of dismantling the reactor pressure vessel and
The fifth step of dismantling the reactor containment vessel and
In the third step, the cutting means has a gantry, a wire saw for cutting the reactor heat shielding wall on the gantry, and a main pulley around which the wire saw is wound. It is provided with a drive unit arranged in the operation area of the above, and is characterized in that the gantry and the drive unit are cut while being swiveled along the outer periphery of the reactor heat shield wall around the reactor pressure vessel in the middle of cutting. How to dismantle the reactor building. A balance that has a surface facing the upper end surface of the reactor heat shield wall and can be inserted from the top opening of the reactor containment vessel with an overhead crane in the reactor building.
A gantry that is placed between the reactor containment vessel and the reactor heat shield wall and can run on the temporary scaffold of the reactor containment vessel or be hung by the balance, and the reactor heat shield wall on the gantry. It has a wire saw that slices the wire saw and a drive unit that has a main pulley around which the wire saw is wound and is arranged in the operation area of the reactor building. A cutting means that enables turning along the outer circumference of the reactor,
A hanging means that can hang a hanging bracket attached to the upper end surface of the reactor heat shield wall that has been sliced into round slices.
A reactor building demolition device characterized by being equipped with.

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