JPS59142499A - Method and apparatus for cleaning polluted surface by radioactive substance - 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 a method for cleaning surfaces contaminated with radioactive substances while preventing radioactive substances from scattering into the working environment in a nuclear reactor-related facility, and an apparatus therefor.

In order to maintain a good environment in a building that houses a nuclear reactor, etc., radioactive substances adhering to the reactor, related equipment, and contaminated surfaces such as the building's interior walls are removed and cleaned. Cleaning involves washing away by spraying water or other cleaning fluids, or by applying a film-forming paint to the contaminated surface and peeling off the formed film, which removes any radioactive substances that may have adhered to the paint film. how to(
For example, there are Japanese Patent Publication No. 3g-, No. 23g07). In these methods, in order to apply a cleaning liquid such as a cleaning liquid or paint to a contaminated surface, a method is adopted in which the liquid is applied by means such as a roller, brush, pad, or spray gun. Among these, when rollers, brushes, pads, etc. are used, the work time is longer due to poor coating workability, which has the drawback of increasing the amount of linear radiation exposure to the worker.

For this reason, cleaning liquid is generally applied by a spray method, which is easy to work with. In addition, the mist of the cleaning solution will scatter, contaminating clean equipment and facilities, and increasing the concentration of radioactive substances in the air. Conventionally, as a means for preventing the scattering of mist and dust in such a spray coating method, the coating operation is performed while the target equipment to be cleaned is isolated using a polyethylene sheet.

There are problems such as deterioration of workability due to the presence of the ethylene sheet and securing a place for cleaning, and there is also the drawback that it does not lead to improvement of the working environment.

The present invention provides a method for cleaning contaminated surfaces by liquid spraying without causing scattering of radioactive substances, and a method for cleaning contaminated surfaces by liquid spraying without causing scattering of radioactive substances, by solving the problems of the method for cleaning surfaces contaminated with radioactive substances according to the liquid spraying method described above. The present invention provides a device for this purpose.

That is, the method for cleaning a surface contaminated with radioactive substances of the present invention is as follows:
This method is characterized in that a cleaning liquid is sprayed onto a surface contaminated with radioactive substances, and the liquid is sprayed onto the contaminated surface by suctioning the vicinity of the contaminated surface. Further, the radioactive material contaminated surface cleaning device of the present invention includes a hood body that opens toward the radioactive material contaminated surface;
This device is characterized by comprising a spray gun having a spray nozzle that opens into the hood attached to the base of the hood body, and a suction pipe attached to the side surface of the hood body with an opening.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

The cleaning liquid used in the present invention is not particularly different from those used conventionally.

That is, in addition to using simple water or a cleaning solution made by adding a decontaminating agent or the like to this water, the Tokko Sho 3g-2! ;g0
A film-forming paint, which optionally contains a decontaminating agent, as described in Japanese Patent No. 7, is preferably used. Note that the decontaminating agents mentioned here include surfactants, citric acid, acetic acid, sodium silicate, various chelating agents, and the like.

The method of cleaning a radioactive material-contaminated surface of the present invention is preferably carried out using the apparatus of the present invention whose perspective illustration of one embodiment is shown in FIG.

Referring to FIG. 1, the device in this example is a paint spraying device that faces and faces a radioactive material contaminated surface A consisting of one surface (in this example, a vertical surface) such as equipment or a building interior wall. A configuration in which a spray nozzle is inserted into the base of a portable hood body having a rectangular opening that gradually expands (
A spray gun is attached as shown in Fig. 1), and a paint supply hose 3 is connected to this spray gun. Further, an opening is provided in the upper side of the hood body l to attach a suction tube, and this suction tube is connected at the opposite end to a treatment device S for removing contaminants.

This processing device 5 has a blower 9 installed at the bottom of a box-shaped main body that houses an eliminator 6 made of coarse mesh paper, a secondary filter, and a secondary filter, and an exhaust duct 10 further installed downstream. The entire structure is movable using casters. In addition, a caster (2) is installed at one location on the open end facing the contaminated surface A of the hood body/, to adjust the gap from the open end of the hood body/ to the contaminated surface, and to adjust the distance along the contaminated surface of the hood body/. This makes it easier to move around.

The mode of coating work using the apparatus of the above example will be explained with reference to FIG. 1 and FIG. 1, which is a sectional view taken along the line ■-■ in FIG. A hood body/equipped with a spray gun is carried over the shoulder and is opposed to a predetermined position of the contaminated surface A via casters t2. Where is the blower? The paint t3 is sprayed by activating the spray coating method while sucking the space inside the hood body l through the suction pipe. The radioactive substances or paint mistakes)/+ scattered from the contaminated surface A by the spraying of the paint 13 pass through the gap between the contaminated surface A and the hood body formed by the casters into the hood body. is drawn into the suction tube q and removed while passing through the eliminator 6 and the filters 7 and g, and the purified air is discharged into the surrounding environment through the duct 10. . It is possible to continuously spray the paint onto the contaminated surface while moving the hood body/and the left side of the treatment device as necessary. Incidentally, as the hood body moves, marks from the caster/2 are produced on the coating surface, but these marks disappear due to the leveling effect of the paint, and an unbroken coating film is obtained as a whole.

As a spray gun, either an airless spray gun or an air spray gun can be used, but when using an air spray gun, the amount of air sucked through the suction pipe should be increased by the amount of air used. It is preferable to do so.

This allows air to flow in through the gap between the contaminated surface A and the hood body, thereby preventing radioactive substances and the like from scattering outside the hood body. Generally, the air velocity flowing through the gap is greater than or equal to sm/sec, especially A, 3~/! ,0m7sec
It is desirable to determine the above-mentioned gap and the amount of air taken in by the blower so that the amount of air is within the range of

As an example, using a hood body with opening dimensions of approximately 3 gm (vertical) x approximately 2 CrIL (horizontal), spraying is carried out with an airless spray gun at a speed of 2t1 minute.
When spraying paint at a pressure of /crl, the gap between the blowing surface A and the hood body is approximately 7.2 cylinders, and the amount of suction gas is approximately q,
o77-1:/min, good coating operation was performed without scattering of radioactive dust etc. to the surrounding area. The air suction speed through the gap corresponds to approximately q, om/sec.

In the above, an example has been described in which paint is sprayed to clean a contaminated surface, but it is of course also possible to spray a cleaning liquid using the same device to clean a contaminated surface. At this time, the cleaning liquid accompanied by radioactive substances and the like flows down through the lower gap of the hood body l, but scattering of contaminants or cleaning liquid mist into the surrounding atmosphere can be similarly prevented.

As described above, according to the present invention, when cleaning a contaminated surface with radioactive substances attached to equipment, equipment, or the inside wall of a nuclear reactor facility building by spraying paint or the like, conventional methods are used. There is a radioactive material that was a problem...
The present invention provides a method and a compact device for the purpose of improving the working environment by preventing paint spills, etc., and carrying out cleaning work efficiently and in a safe environment for workers.

[Brief explanation of the drawing]

Fig. 1 is a perspective explanatory view of one embodiment of the apparatus for cleaning surfaces contaminated with radioactive substances of the present invention, and Fig. 2 is for explaining the usage situation of the apparatus taken along the line ■-■ in Fig. 1. FIG. /... Hood body, Co... Spray gun, T... Suction tube, S... Processing device for removing contaminants, 6
~g... Filters, Wa... Blower, IO...
Exhaust duct, /co...caster, A...radioactive material contaminated surface. h i diagram

Claims (1)

[Scope of Claims] / A method for cleaning a surface contaminated with radioactive substances, characterized in that a cleaning liquid is sprayed onto the surface contaminated with radioactive substances, and the sprayed liquid on the contaminated surface suctions the vicinity of the contaminated surface. The λ cleaning liquid is a film-forming paint, and by peeling off the formed paint film, radioactive material contamination can be removed. A cleaning device for a surface contaminated with radioactive substances, comprising a spray gun equipped with a spray nozzle and a suction pipe attached to the side surface of the hood body with an opening. 5. The spray gun is an airless spray gun and is the device described in item 1 above. The apparatus according to item 3 or 3 above, wherein casters are attached to a plurality of locations on the open end of the hood body facing the contaminated surface, so that the hood body can be moved parallel to the contaminated surface and with a predetermined gap therefrom.