JPS5811306B2 - Underwater cutting device for radioactively contaminated metal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an underwater cutting device for radioactively contaminated metal, and in particular, it can easily dismantle radioactively contaminated metal (hereinafter referred to as metal to be cut) by arc-cutting the metal with a fusing torch. The present invention relates to a device for reducing volume.

When materials such as reactor internal structures deteriorated and were to be disposed of, they were stored in the fuel pool, but in recent years the amount of such material has increased.
In particular, since channel boxes and control rods are regularly disposed of, it has become necessary to dismantle them or cut them to reduce their volume before storing them.

However, these metals to be cut are highly contaminated with radioactive materials or are themselves radioactive, so
From the standpoint of preventing radiation exposure to workers, it is necessary to perform underwater remote control.

Conventionally, it has been known to use underwater cutting technology for channel boxes among these metals to be cut.
For example, pressing, shearing, punching, or a combination of these mechanical cutting methods have been used.

However, in the case of mechanical cutting, there are disadvantages in that the number of parts is large, the device is complicated, and various mechanical parts must be installed underwater.

Furthermore, as the equipment becomes larger and more complex, maintenance becomes more frequent and the time taken to prepare for operation increases, which poses the risk of increased radiation exposure.

On the other hand, control rods have disadvantages to remote cutting, such as their complicated shape and the need to prevent the neutron absorption rods from falling off during processing, so they have not yet been made into a device.

The inventors of the present invention have made extensive studies to solve the above-mentioned drawbacks of the prior art, and as a result, have arrived at the following invention.

That is, the present invention disposes a collecting tool for collecting sediment at the lower part of a container with an open top, which is installed underwater, and also stores at least a cutting part of radioactively contaminated metal and a fusing torch in the container. and a mechanism for moving the relative positions of the radioactively contaminated metal and the fusing torch, and a water circulation path of the purification mechanism for purifying the water in the container, one end of which is connected to the lower part of the container,
This is an underwater cutting device for radioactively stained metal, characterized in that the other end is connected to the upper part of the container.

Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIG. 1 is an explanatory diagram showing an embodiment of the present invention, in which a metal to be cut 1 is held at one end by a gripping tool 2.
is connected to a handling device 3 and is movable in the vertical direction by the handling device.

In addition to the vertical movement of the gripping tool 2, the handling device also
It is configured to be movable in the left and right directions.

The metal to be welded 1 is housed in a container 4.
A collection tray 5 is installed at the bottom of the container 4, and a fusing torch 6 is fixed to the side wall of the container 4.

All of these devices, except for the handling device 3, are installed underwater.

The fusing torch 6 is connected to an arc control system 7 via a line 8.

The arc control system 7 can also be installed above water.

In addition, the bottom end of the container 4 is connected to the filter 1 via a line 9.
0 and a pump 11, and further connected to the side wall of the container 4 via a sparger 12.

The line 9 filter 10, pump 11, and sparger 12 constitute a purification mechanism.

This purification mechanism can be installed above water, and the filter can also be installed underwater.

The metal to be cut 1 housed in the container 4 is fixed at an appropriate position by operating the handling device 3.

Next, the arc control system 7 operates to supply arc working fluid, etc., and the fusing torch 6 operates to move the metal to be cut 1 up and down to melt it. During the fusing operation, which is carried to a storage pool (not shown) while being held by the container 2, relatively large solids called dross, small suspensions, or hydrogen due to decomposition of water are generated. The water within 4 becomes polluted.

In the present invention, among these, solids with a relatively large particle size sink to the bottom and are collected on a collection tray 5 formed of a lattice structure, a perforated plate, gilt copper, etc., and the collection tray 5 is taken out as appropriate. Process.

In this embodiment, since the metal to be cut 1 can be moved three-dimensionally by the handling device 3, the metal to be cut 1 can be cut into various shapes as required.

Therefore, if the relative position of the melt-cutting torch 6 is moved in the horizontal direction, the melt-cut metal 1
will fall onto tray 5, and this tray 5 will be
will be taken out from container 4.

Further, the water in the container 4 contaminated with suspended matter having a small particle size passes through a line 9, is filtered by a filter 10, and is filtered by a pump 11.
The water is then refluxed into the container 4 via the sparger 12.

Therefore, the water in the container 4 is constantly purified, and continuous operation can be continued for a long period of time.

FIG. 2 is an explanatory diagram showing another embodiment, which is the same as the embodiment shown in FIG. 1 in that the metal to be cut 1 is moved.
The metal 1 is held horizontally at both ends, and is held by a handling device 3.
is moved left and right by

Although the container 4 of this embodiment is narrow in width and cannot accommodate the entire metal 1 to be welded, since the fixed fusing torch 6 is housed in the container 4, at least the fusing part is accommodated in the container 4. become.

Of course, the container 4 may be made large and the entire metal to be cut 1 may be movable within the container 4.

In addition, in the examples shown in these FIGS. 1 and 2,
Although the fusing torch 6 is fixed and the metal to be cut 1 is moved up and down or left and right, the present invention is not limited to this, and the former is moved up and down or left and right and the latter is fixed. Good too.

That is, the relative positions of the metal to be cut 1 and the cutting torch 6 may be moved.

Moreover, although the case where one fusing torch 6 is provided has been described, it is also possible to provide two or more depending on the fusing shape of the metal 1 to be welded.

The device of the present invention has the following advantages.

(1) When melting is performed by moving the relative position of the metal to be melted and the melting torch, a complicated moving mechanism is not required, resulting in an extremely simple configuration.

Furthermore, since the device mechanism is simple, parts replacement, maintenance, and repair are less frequent and safer.

(2) Regardless of whether the cutting direction of the metal to be cut is vertical or horizontal, it can be handled as appropriate by changing the moving direction of the object to be cut or the cutting torch.

(3) Since the purification mechanism is installed in parallel with the underwater cutting device, the contaminated water in the container is purified by the purification mechanism, so that the device can be operated continuously for a long period of time.

Furthermore, since the melting is done within the container, suspended matter caused by the melting work is not spread throughout the pool.

(4) When the device of the present invention fulfills its function and becomes contaminated waste, it is easy to disassemble and reduce the volume because of its simple structure.

(5) According to the device of the present invention, it becomes possible to cut and reduce the volume of control rods, which has been impossible until now.

As explained above, according to the present invention, since a collecting tool for collecting sediment is disposed at the lower part of a container with an open top, which is installed underwater, relatively large particles generated during fusing work can be removed. Sediment such as large solids can be collected using this collecting tool, and the collecting tool can be taken out and treated as appropriate.

In addition, the water circulation path of the water purification mechanism in the container was installed so that one end was connected to the bottom of the container and the other end was connected to the top of the container. The turbid water in the container enters the circulation path from the bottom of the container, is purified by a filter, etc., and then flows back into the container from the top.
The water in the container is constantly purified.

Therefore, even if the top end of the container is open, suspended water will not diffuse out of the container.

Further, since the upper end of the container is open, it is not only easy to insert and remove the metal to be cut, but also to observe and check the insertion, cutting, etc., as necessary.

Therefore, according to the present invention, it is possible to easily, safely and efficiently cut radioactively contaminated metal underwater.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing another embodiment. 1... Radioactively contaminated metal, 3... Handling device, 4... Container, 5... Collection tray, 6... Fusing Torch, 7...Arc control system, 10...Filter.

Claims (1)

[Claims] 1. A collection device for collecting sediment is arranged in the lower part of a container with an open top, which is installed underwater, and at least a cutting part of radioactively contaminated metal and a cutting torch are stored in the container,
A mechanism for moving the relative positions of the radioactively contaminated metal and the fusing torch is provided, and a water circulation path of the purification mechanism for purifying the water in the container is connected at one end to the bottom of the container and at the other end to the top of the container. An underwater cutting device for radioactively contaminated metal, characterized in that it is connected to each other.