JPH0192696A - Method for cutting and disassembling cylindrical structure - Google Patents

Abstract

PURPOSE:To completely disassemble the thermal shielding wall (RSW) of a boiling water reactor by cutting the structure by a remote controlled abrasive jet from upward to downward directions to small blocks of prescribed sizes, then ejecting the blocks. CONSTITUTION:A cutting device 10 is hoisted by means of a crane with a wire rope 6 and is lowered until a guide frame 12 bestrides the RSW 1. A pressing jack 11 is extended and is fixed to the RSW 1 and the wire rope 6 is removed. The upper part of the RSW 1 is covered by a steel cap (not shown). An abrasive jet device is then driven to deliver ultra-high pressure water from a nozzle 19. The RSW 1 is cut to an L shape by moving the nozzle downward then transversely. The guide frame 12 is then moved toward the right and the cutting is similarly executed to cut the RSW 1 to the prescribed small block 1A. The small block 1A is hoisted and ejected by the crane. A device (not shown) for treating slurries and exhaust gases is provided as well.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for cutting and dismantling a cylindrical structure such as a heat shield wall (R3W) of a boiling water type (BWR type) nuclear power plant.

[Technical Background and Prior Art] The major difference between the demolition of such concrete structures and the demolition of general structures is that they are radioactive (changed into new radioactive materials) and that they are not contaminated with radioactive materials. The main reason for this is that there are many concrete structures with a large amount of reinforcing steel.

For this reason, since workers cannot approach the activated parts, it is necessary to dismantle them by remote control and prevent the activated dismantled pieces and dust from scattering.

[Object of the Invention] Therefore, an object of the present invention is to provide a structure cutting and demolition method for cutting and removing a cylindrical reinforced concrete structure into blocks.

[Structure of the Invention] According to the present invention, in a method of cutting and dismantling a cylindrical structure from the outer wall side, the structure is sequentially axially and circumferentially moved from above to below using an abrasive jet under remote control. It is cut into small blocks of predetermined dimensions, and the cut blocks are transported out.

[Operations and Effects of the Invention] Therefore, for example, when dismantling the heat shielding wall of a BWR type nuclear power plant, it is possible to cut it into small blocks by cutting from the top to the bottom to a predetermined size by remote control, and then transport the cut small blocks. can be dismantled and removed safely without posing any danger to humans.

[Preferred Embodiment] In practicing the present invention, it is preferable to use a slurry and exhaust treatment device. In this way, for example, it is possible to prevent radioactive dismantled pieces and dust from scattering.

[Example code] The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a case where the cutting and dismantling method of the present invention is applied to, for example, a heat shield wall (hereinafter referred to as R8W) 1 of a BWR type nuclear power plant.

In the figure, BSWI is 10 m in diameter and approximately 15 m in height.
It is a cylindrical steel structure with a thickness of about 60 cm, consisting of inner and outer shells made of thick steel plates with a thickness of about 30 to 45 cm, and shell partition plates, and filled with concrete or mortar. It is housed in a reactor containment vessel (PCV) 3 covered by a nuclear reactor containment vessel (PCV) 2.

The abrasive jet cutting and dismantling device according to the present invention includes a cutting device 10 set in the cutting section of the BSWI, an abrasive jet device 20, a slurry treatment device 30, and an exhaust treatment device 40. Existing cranes 5 and 51 in the building 4 are used as heavy processing equipment.

In FIGS. 2 and 3, the cutting device 10 includes a BSW
A guide frame 12 having a downward U-shape, which is fixed by a jack 11 and has an extension 12a protruding from the lower end in one direction of the cylinder (to the right in the illustrated example), and a lifting guide for the guide frame 12. Elevating roller 1 on rail 13
4 and is lifted and lowered by a lifting pinion gear motor 16 that meshes with the lifting rack 15a.
It consists of a soundproof/water leakage cover 18 that is traversed by a motor 17 of a traverse pinion gear that meshes with a traverse rack 15b provided at 2a, and a jet nozzle 19 that is provided on the cover 18 toward the center of the BSWI.

In FIG. 1, the abrasive jet device 2O includes an ultra-high pressure pump 21, an abrasive tank 23, and a monitoring control panel 2.
It consists of 5. The ultra-high pressure pump 21 is connected to a supply water source (not shown) and to the jet nozzle 19 via a high-pressure water pipe 22 , and the abrasive tank 23 is connected to the jet nozzle 19 via an abrasive pipe 24 . The monitoring I (J press board 25) includes an abrasive jet device 20, and the entire cutting and dismantling device is controlled by remote control.

The slurry processing device 30 includes a slurry receiving tank 30a provided at the bottom of the BSWI, a pump 32 connected to the tank 30a and a submersible pump 31a provided at the bottom of the PCV 3 via a slurry discharge pipe 31, and a pump 32. A magnetic separator 33 provided on the downstream side, an abrasive receiver 34 that receives the abrasive separated by the magnetic separator 33, a raw water tank 35 that receives water from the magnetic separator 33, a raw water pump 36, and a raw water pipe 36a A flocculation reaction tank 37 connected to the raw water tank 35, a sedimentation tank 38 provided downstream of the flocculation reaction tank 37, and a sedimentation! 3
It consists of a sludge receiver 38a that receives the sludge separated in step 8, and a treated water tank 39 that receives water from the settling tank 38. In addition, the code|symbol 31b in the figure is a slurry discharge pipe for the suspended slurry receiving tank 30a.

The exhaust treatment device 40 covers the upper end opening of the BSWI.
From a cooling heat exchanger 43 connected to the lid 41 via an exhaust pipe 42, a mist eliminator 44, an electric heater 45, a filter 46, and a turbo blower 47 provided in this order on the downstream side of the heat exchanger 43. , heat exchanger 43
and the mist eliminator 44 are connected to the slurry discharge pipe 31 of the slurry treatment device 30 via a pipe 48, and the turbo blower 47 is connected to an existing exhaust treatment facility (not shown).

Next, embodiments of the present invention will be described.

First, the cutting device 10 is suspended by the wire 6 using the crane 5, and lowered so that the guide frame 12 straddles the BSWI.For pressing, the jack 11 is extended and fixed to the BSWI, the wire 6 is removed, and the steel lid 41 is set. .

Next, the abrasive jet device 20, the slurry treatment device 30, and the exhaust treatment device 40 are operated, and the motor 16 of the lifting pinion gear is driven to control the nozzle 19 at a speed of, for example, 2.9 mm.
The R8WI is lowered by 8 m, the motor 17 of the traverse pinion gear is driven, and one nozzle is traversed by 1.48 m, for example, to cut R8WI into an L-shape using an abrasive jet. At this time, the slurry is collected in the slurry receiving tank 30a at the inner bottom of the R3WI, the slurry leaking to the outside of the RSWI is treated by the slurry treatment device 30 via the submersible pump 31a at the bottom of the PCV3, and dust and gas are collected by the exhaust treatment device 40. will be processed. Note that the receiving tank 30a is lifted up by the crane 5 at appropriate times and the slurry is discharged into the slurry discharge pipe 31b.

Next, in the same manner as described above, the guide frame 12 is moved to the right in the circumferential direction by, for example, 1.48 m and fixed to the right side of the previously cut L-shaped part, and R3WI is cut into an L-shape, for example. Cut into small blocks IA of 1.48 m square and 2.9 m long.

Next, crane 5 lifts small block IA (fourth
Figure 5) is carried out to Building 4 and re-lifted by crane 51.
(Fig. 6) and stored in a container 52 (Fig. 6).

[Summary] As explained above, according to the present invention, R
Since a structure such as 8W is cut into small blocks of a predetermined size from the top to the bottom and stored in a container, the dismantling process can be carried out safely without posing any danger to the human body.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an apparatus for implementing the present invention, FIG. 2 is a perspective view showing a cutting device, FIG. 3 is a radial cross-sectional view of FIG. 2, and FIGS. 4, 5, and 6. 2A and 2B are perspective views showing the process of carrying out small blocks, respectively. 1...Heat shielding wall (R3W) IA...Small block 10...Cutting device 18...Soundproof/water leakage cover 19...Jet nozzle 20...Abrasive jet equipment W30...Slurry Processing device 40
...Exhaust treatment equipment Fig. 5 Fig. 4

Claims (1)

[Claims] In the method of cutting and dismantling a cylindrical structure from the outer wall side,
A cylinder characterized by cutting the structure into small blocks of predetermined dimensions by sequentially cutting the structure from above to below in the axial direction and circumferential direction using an abrasive jet under remote control, and transporting the cut blocks. Cutting and demolition method for shaped structures.