JPS6039599A - Device for removing loaded and stacked clad - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for removing deposited crud at the bottom of a nuclear reactor well.

Each time a nuclear reactor undergoes a periodic inspection, the well is filled with water, and fuel and other materials are moved underwater. Therefore, radioactive crud in the reactor water overflows into the well. The inside of the well is decontaminated in preparation for the restart of reactor operation, but the bottom of the well is particularly uneven and irregular, making it extremely difficult to remove the highly radioactive crud deposited on the saws through isolation work. Conventionally, attempts have been made to remove the crud in this area by using a crane to pump suction, but this is a partial operation and requires manual work.

The present invention aims to quickly vacuum and remove deposited crud on the bottom of an irregularly shaped well by remotely controlling a truck equipped with a pump and a group of suction pipes at the bottom of a reactor well.

The present invention, which has been made to achieve this object, is summarized as follows. That is, a self-propelled truck is straddled over the irregular bottom portion of the reactor well, and the truck is connected to a suction pump and arranged in its original state.

A group of flexible tubes with a suction port at the tip are swept over the irregularities at the bottom of the reactor well to suction and remove the deposited crud.

Next, an example will be described. In FIG. 1, reference numeral 5 denotes a cart which is self-propelled by a drive device 3 along a rim 2 surrounding the well bottom 1 in a circumferential manner. Also, a cart 5 supported by four wheels 4
straddles the protrusion 6 to the extent that it does not touch it. Trolley 5
A large number of flexible tubes 7 having suction ports at their tips are suspended down to the ground in their original state, and their upper ends are joined to a main tube 8 and connected to a water suction tube 10 of a pump 9. The flexible tube 7 may be formed of a soft tube made of rubber or plastic, a hard tube connected with a flexible tube with a soft joint, or a hard tube connected with a flexible tube with a hard flexible joint. (swivel joint).

When the truck 5 travels in the direction of the arrow 11, the cladding 12 is swept by the flexible tube 7 and substantially the entire area is cleaned. Note that the flexible tube 7 blocked by the protrusion 6 swerves to the left and right so that it does not interfere with running.

In the direction of arrow 11, which is the first travel in FIG. 2, residual cladding 13 remains behind the protrusion 6, and a small amount of residual cladding 14 remains in front. Next, arrow 15 for the second reverse run in Figure 3
In this direction, the residual crud 13 (FIG. 2) in front of the protrusion 6 is mostly sucked out, and eventually a small amount of residual crud 14.1
Only 6 remains.

Further, washing water 18 is supplied to the well bottom 1 as needed to facilitate suction removal of the cladding 12.

In addition, since the flexible tubes 7 each have suction ports adjacent to each other, the openings are dispersed, and even if a part of the flexible tubes splashes into the air from the water surface 17 while traveling, the cladding 12 The deterioration of suction pressure does not occur to the extent that suction is inhibited.

In this way, rapid and efficient suction decontamination was possible despite the well bottom 1 having irregularly shaped protrusions. Note that the first
If the cart 5 shown in the figure is also equipped with a high-pressure pump 19, its injection nozzle 20, a brush 22 rotated by a power equipment 21, and a clad suction pipe 24 connected to the suction water pipe 10 of the pump 9, the groove 23 can be decontaminated quickly and reliably. is also possible.

Although not shown in the diagram, the power supply, air supply,
Water and other supplies as needed will be communicated and supplied in the usual way.
The discharge crud of the pump 9 is transferred to a filtration device or a storage tank as required.

Moreover, remote control of the deposited crud removal apparatus can be carried out in a conventional manner to bring out the performance of the apparatus.

As described above, according to the present invention, it is possible to bring about the following effects that have not been obtained conventionally.

1) Dense, high-dose crud can be quickly and reliably removed by suction.

2) Even well bottoms with irregularly shaped parts such as protrusions can be decontaminated at once with practical precision using the device of the present invention.

3) The crud dispersed in various parts of the well bottom can be simultaneously removed using the original suction pipe group, contributing to shortening the period of periodic inspection of the reactor.

4) Prevents exposure to radiation as remote control is possible from a remote location.
6.Final decontamination of the bottom of the reactor well requires further use of floor cleaning equipment.
Provides a highly clean finish. The initial decontamination work can be sufficiently carried out by the apparatus of the present invention to the extent that it does not hinder the access of workers at that time.

[Brief explanation of drawings]

FIG. 1 shows an apparatus for removing deposited crud according to the present invention. FIGS. 2 and 3 are explanatory diagrams of the sweep results for the mini protrusion irregularities. In the figure: l Well bottom 2 Rim Embankment 3 Drive device 4 Axle 5 Car 6 Projection 7 Flexible pipe 8 Main pipe 9 Pump 1o Water suction pipe 11 Arrow 12 Cladding 3 Residual cladding 14 Residual cladding 15 Arrow 16 Residual cladding 17 Water surface 18 Cleaning water 19 High pressure pump 2o Injection nozzle 21 Power equipment 22 Brush 23 Groove 24 Clad suction pipe and above Applicant Atomic Energy Co., Ltd. Agent Patent attorney Isamu Ohashi 2nd WJ This 3rd WJ

Claims (1)

[Claims] A self-propelled trolley is straddled over the irregular part of the bottom of the reactor well, and a group of flexible tubes connected to the suction pump from this trolley and arranged in their original shape and having a suction port at the tip are connected to the irregular part of the bottom of the reactor well. A deposited crud removal device that sweeps over the surface to suction and remove deposited crud.