JPH0342800B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a falling slag recovery device for recovering fallen slag generated at the bottom of a reactor when the inner wall of a nuclear reactor is cut.

(Technical background) To dismantle a nuclear reactor, the radioactively contaminated inner concrete walls must be dismantled and removed while safely isolating them to prevent contamination of human bodies or the atmosphere.

Therefore, in order to cut the inner concrete walls, cutting with a burning bar is carried out safely and efficiently using remote control, and the demolition blocks created by the cutting are also transported and removed while being completely isolated from human bodies and the atmosphere. There is a need.

On the other hand, when cutting with a burning bar, fine slag is produced as a by-product in addition to the cutting blocks. Since this slag is also contaminated with radioactivity, it must be transported and removed in a completely isolated state, just like the cutting blocks.

Furthermore, since this slag scatters and falls during cutting, it must be appropriately collected at the bottom of the furnace and the collected fallen slag must be recovered.

(Object of the Invention) The present invention has been made in view of the above points, and is a method for safely collecting and recovering slag generated when cutting the inner wall of a nuclear reactor, the so-called concrete heat shield wall, by remote control. The present invention provides a device for collecting fallen slag to be carried out and removed.

(Summary of the Invention) The fallen slag recovery apparatus of the present invention includes a cylindrical side wall provided on a rotary table placed at the bottom of a nuclear reactor to form a slag receiving tank. A weir plate is installed in this receiving tank, and a crushing beam is installed at the top of the slag receiving tank to crush the falling slag, which falls to the bottom of the reactor by this recovery device. The system collects and transports fine slag safely and efficiently using remote control.

(Example) Hereinafter, a fallen slag recovery device of the present invention will be explained with reference to the drawings.

FIG. 1 is a partially cutaway perspective view illustrating the dismantling work of a nuclear reactor. To outline the dismantling work of a nuclear reactor, an enclosure 10 is installed on top of the reactor head 1a of the reactor 1.
Built in and shielded from inside the furnace and outside. A gantry 20 is installed on the upper side 11 of this enclosure 10.
A lifting device 30 is provided, through which a main shaft 40 is suspended within the furnace.

A cutting device 5 is installed at the lower end of this main shaft 40.
0 is provided, and the gantry 20, elevator 30 and main shaft 40 act as a support drive for the cutting device 50.

That is, as the elevating device 30 traverses, ascends and descends, and rotates, the cutting device 50 moves horizontally and vertically via the main shaft 40, and also rotates horizontally. The cutting device 50 is equipped with a cutting machine that injects and burns fuel using a burning bar to perforate holes, and the inner wall of the nuclear reactor 1 is cut into blocks by this cutting machine. The cutting block cut by the cutting device 50 is gripped by a gripping device 60 that moves up and down using the main shaft 40 as a guide, and is then held by a loading/unloading lock device 70 provided in the enclosure 10.
It is carried out to the outside via a conveyance device.

As described above, when the inner wall is cut by the cutting device 50, molten slag is generated during the injection combustion of the burning bar, which falls to the furnace bottom 1b and scatters. A slag recovery device 80 is arranged at the hearth bottom 1b. The slag that has fallen into the slag recovery device 80 is collected as will be described later, and is dropped by the bucket device 81 into a storage container of the carry-in/out lock device 70, and the container is sealed and carried outside.

2 to 4 explain the slag recovery device 80, FIG. 2 is an explanatory view taken along the line A-A in FIG. 1, FIG. 3 is an explanatory view taken along the line B-B in FIG. FIG. 4 is an explanatory diagram taken along the line C--C in FIG. 3.

To further explain the slag recovery device 80 based on these explanatory diagrams, a rotary table 82 is provided at the hearth bottom 1b.
is provided. The rotary table 82 has a disk shape with a size approximately equal to the diameter of the hearth bottom 1b. This rotary table 82 is rotated in a fixed direction approximately around the core by, for example, two rotary motors M, M.

Also, a cylindrical side wall 8 is provided on the upper surface 82a of the rotary table.
3 are arranged along the inner periphery of the hearth bottom 1b. That is, the rotary table 82 and the cylindrical side wall 83 placed on its upper surface 82a form a circular tank, a so-called slag receiving tank 84. In this slag receiving tank 84, the rotary table 82 and the cylindrical side wall 83 must not be fixed integrally.

On the other hand, a weir plate 85 is arranged in the slag receiving tank 84 so as to have a constant angle with respect to the rotation direction of the rotary table 82 (as viewed by the arrow in FIG. 2). This weir plate 85
is not fixed to the rotary table 82, that is, when the rotary table 82 rotates, the weir plate 85 scrapes the slag that has fallen onto the upper surface 82a of the rotary table and collects it in a predetermined cylindrical position in front of the weir plate 85.

A crushing beam 86 is provided at the top of the receiving tank 84,
This crushing beam 86 consists of an annular outer ring beam 86a along the inner periphery of the furnace shape and an inner ring beam 86b having a smaller diameter, and both beams are connected by connecting beams 86c, 86c, . . . . So-called ridge-like acute angle portions are formed on the upper surfaces of these beams, and when falling slag collides with the crushing beam 86, the ridge-like acute angle portions crush the slag into fine pieces. Also, in order to carry out the slag collected in front of the weir plate 85, a bucket 81 is introduced from above. Therefore, it is necessary to form a bucket inlet 87 in a part of the crushing beam 86 stretched above the receiving tank 84. As shown in FIG.
lower to the specified position. A weir plate 85 is provided at a position downstream in the rotational direction of the rotary table 82 from that position,
Further, a bucket inlet 87 is provided at the front upper part of the weir plate 85 in the rotational direction.

The operation of collecting and transporting slag using the slag collecting device 80 having the above configuration will be described below.

The slag generated as a by-product by the cutting operation of the cutting device 50 collides with the crushing beam 86 as it falls through the furnace and is further crushed into fine pieces, becoming fine slag and scattering into the slag receiving tank 84. The slag falls almost uniformly onto the so-called table top surface 82a. Then, when the rotary motors M and M are driven to rotate the rotary table 82 in the direction of the arrow in FIG.
The slag on the top surface 82a of the rotary table is pushed forward by the weir plate 85 and is so-called scraped, and when the rotary table 82 rotates once, the slag on the top surface 82a of the rotary table
Most of the slag above a is collected in front of the weir plate 85. Next, the bucket 81 is lowered from the basket input port 87 provided at the front upper part of the weir plate 85, and the bucket shell is opened to store the slag.
It is to be carried out. The slag carried out by the bucket 81 is dropped into the storage container of the loading/unloading lock device 70, and by sealing the storage container itself, it is safely transported outside.

(Effects of the invention) As described above, the falling slag recovery device of the present invention has the following features:
The rotary table has a cylindrical side wall to form a slag receiving tank, a weir plate is installed inside this receiving tank, and a crushing beam is installed on the top.The structure is such that falling slag is crushed and evenly processed. The slag is scattered in the receiving tank and is easily collected at a certain location by the rotation of the rotary table, and the collected slag can be completely transported out using a transporter such as a bucket.

Therefore, the recovery device of the present invention can safely and reliably remove fine slag, which is a by-product, by remote control during large-scale cutting operations such as nuclear reactor dismantling.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view illustrating nuclear reactor dismantling work, and FIGS. 2 to 4 are illustrative of the slag recovery device of the present invention. 3 is an explanatory view taken along the line B-B in FIG. 1, and FIG. 4 is an explanatory view taken along the line C-C in FIG. 3. 1... Nuclear reactor, 1a... Reactor head, 1b... Reactor bottom,
80...Slag collection device, 81...Bucket, 8
2... Rotary table, 83... Cylindrical side wall, 84...
... Slag receiving tank, 85 ... Weir plate, 86 ... Crushing beam,
87...Bucket inlet.

Claims (1)

[Claims] 1. A slab receiving tank is formed by a rotary table disposed at the bottom of the furnace and a cylindrical outer wall arranged around the outer periphery of the rotary table and fixed to the bottom of the furnace; A falling slag recovery device, characterized in that a weir plate is fixedly provided on the side wall, and a crushing beam is fixedly arranged on the upper part of the side wall.