JPH0682160B2 - Method for containing radioactive contaminants and cracks on the surface of radioactive waste containers - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to the containment of radioactive contaminants adhering to the surfaces of radioactive waste containers and equipment, and a method for containing cracks on the surfaces of these containers and equipment.

[Prior Art] Conventionally, when radioactive contaminants are attached to the surface of a radioactive waste container or the container is cracked to make it difficult to repair, for example, Nuclear Industry, Vol. 32, No. 11, From page 37
As discussed on page 43, a process has been taken in which each container is placed in a separate container and sealed.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technique, a separate container is required even when the radioactive contaminants are locally attached or when the cracks are small. Equipment for sealing the lid is required.

Especially for radioactive waste containers that have high radioactivity levels and cannot be accessed directly by humans, a device for remote construction is required, and the above-mentioned conventional technology is technically difficult and economically burdensome. Become.

An object of the present invention is to provide a method for easily containing radioactive waste if the adhesion is localized or the cracks are small.

[Means for Solving Problems] The present invention relates to a radioactive waste container or other container or a radioactive contamination or radioactive waste container attached to the surface of a device,
In addition, a metal or ceramic is sprayed on the surface of the container or device so as to cover the cracks generated in the container or device containing the radioactive substance, and a sealing compound such as a resin compound or glass is applied on the sprayed coating. It is characterized in that the sprayed pores are sealed and the radioactive contaminants or cracks are sealed.

[Operation] The bonding force between the thermal spray coating and the object differs depending on the material of the thermal spray material and the object, the pretreatment state of the object surface, the surface roughness, the shape of the peaks and valleys of the surface roughness, etc. Mechanical bonding that occurs when the thermal spray material digs into the rough surface of the object, bonding due to the proximity of atoms to the object, metal bonding due to local melting, etc. are generally considered, and generally resin etc. are directly applied. Higher adhesion is obtained than in the case.

However, since the thermal spray coating is formed by laminating the thermal spray material, even if the thermal spray material is metal or ceramics,
The porosity is high and the sealing performance is not good up to this point.

Therefore, in the present invention, the sprayed pores are sealed by further coating a resin compound such as paint or glass on the sprayed coating. Since the surface of the thermal spray coating is a rough surface due to the laminated formation of the thermal spray material, the resin compound, glass and the like increase the mechanical bonding force by biting into the thermal spray coating, and a high adhesive force is obtained.

[Examples] Examples of the present invention will be described below.

FIG. 1 shows a method of containing radioactive contaminants 12 on the outer surface 11b of the wall 11a of the radioactive waste container. In this case, the contaminant 12 is an object to be contained, and first, a metal or ceramic material is sprayed on the outer surface 11b of the container so as to cover the contaminant 12 to form a sprayed layer 13 on the contaminant 12. It is necessary to appropriately decide whether to select metal or ceramics as the thermal spraying material, but generally, if the container is made of a metal material, a metal is selected, and if the container is made of a ceramic material, a ceramic is selected. For example, stainless steel can be selected as the metal and gray alumina can be selected as the ceramics. The thermal spray layer 13 sandwiches the contaminant 12 with the outer surface 11b of the radioactive waste container, or encloses it in the thermal spray layer 13 to exert a containment action. However, since the thermal spray coating has a laminated structure in which granular thermal spray materials are stacked, the porosity is generally high, and the sealing property cannot be obtained up to this point.

Therefore, a resin compound (eg, epoxy resin) 14 such as paint is further applied as a sealing material on the thermal spray layer 13 to seal the pores of the thermal spray layer 13. Other than this, a material having a good airtightness such as glass may be used as the sealing material. Since the surface of the thermal spray layer 13 is a rough surface formed by laminating granular thermal spray materials, there is an advantage that the resin compound, glass and the like enter the ridges and valleys of the surface of the thermal spray layer 13 to increase the adhesive force.

FIG. 2 shows an embodiment in which the wall 11a of the radioactive waste container has a crack 15, and the object to be contained in this case is the crack 15. The sealing method is the same as in the case of FIG.
And then sealed with resin compound or glass 14.

Incidentally, it is generally known that, in the thermal spraying process, it is known that the surface of the coating object is sufficiently washed, and that the surface having an uneven surface gives a stronger adhesive force.
Also in FIGS. 2 and 3, it may be considered that the outer surface 11b of the radioactive waste container is polished by sand pressure feeding or the like to form an uneven surface before the sprayed layer 13 is formed.

FIG. 3 shows a structural example of an apparatus for performing the thermal spraying work. Generally, it is desirable to handle radioactive waste containers by remote control from the viewpoint of reducing the exposure of workers.
In the illustrated example, the thermal spraying is performed using the remote thermal spraying device 23. The radioactive waste container 21 is placed on the installation table 22. Remote spraying equipment 23
Is, for example, an articulated arm type robot, and a spray gun 24 attached to the tip of the robot can freely move to a spray target position. A thermal spray material supply hopper 25 and a thermal spray material supply hopper 25 are supplied to the thermal spray gun 24 from a gas cylinder 26, and the thermal spray material is melted in the thermal spray gun 24 by high frequency power from a high frequency generator 27 and sprayed onto an object. Also a spray gun
24 is cooled by the cooling water sent from the cooling water device 28. Control of each of these devices is performed by the control device 29, enabling remote construction.

FIG. 4 shows an example of the constitution of the apparatus for performing the above-mentioned paint application, which is performed by remote control as in the case of the thermal spray application in FIG. The radioactive waste container 21 is placed on the table 22. The remote painting device 31 for painting is, for example, an articulated arm type robot, and a painting gun 32 is attached to the tip thereof. The paint gun 32 is supplied with paint and compressed air from a paint tank 33 and an air compressor 34, respectively, and sprays them onto an object. The control of each device is performed by the control device 35, which enables remote construction.

In FIG. 2 and FIG. 3, since the radioactive waste container 21 is the same, the remote spraying device 23 and the remote coating device 31 are shared, and the spray gun 24 and the coating gun 32 at the tip are replaced. , It is a matter of course that each construction may be performed by one device.

The present invention can be applied not only to the radioactive waste container but also to contain radioactive contaminants adhering to the surface of other containers or equipment, and not only to the radioactive waste container but also to contain radioactive substances. Of course, it can be applied to the containment of cracks generated in the container and the equipment.

[Advantageous Effects of the Invention] According to the present invention, radioactive waste containers and other containers, the containment of radioactive contaminants adhering to the surface of the device, and the containment of damage such as cracks on the surfaces of these containers and devices are locally carried out. In addition, it can be easily performed, and has an effect that the economical burden can be reduced and remote operation can be facilitated as compared with the conventional method of sealing in a separate container.

[Brief description of drawings]

The drawings each show an embodiment of the present invention.
Figure is a cross-sectional view showing the containment method when contaminants are attached to the surface of the radioactive waste container, and Figure 2 is a cross-sectional view showing the containment method when the radioactive waste container is cracked. FIG. 3 and FIG. 3 are illustrations of an apparatus configuration for performing remote thermal spraying, and FIG. 4 is an illustration of an apparatus configuration for remotely applying paint or the like. (Explanation of symbols) 11a ... wall of radioactive waste container, 11b ... outer surface of radioactive waste container, 12 ... contaminant, 13 ... sprayed layer, 14 ... resin compound, 15 ... crack, 21 ... radioactive waste container, 22 ... Installation stand, 23 ... Remote spraying device, 24 ... Spraying gun, 25 ... Spraying material supply hopper, 26 ... Gas cylinder, 27 ... High frequency generator, 28 ... Cooling water device, 29 ... Control device, 31 ... Remote coating device, 32 ... Painting gun, 33 ... Paint tank, 34 ... Air compressor, 35 ... Control device.

Claims (2)

[Claims] 1. A method for containing radioactive contaminants adhering to the surface of a radioactive waste container or other container or equipment, or a crack generated in a radioactive waste container or other container or equipment containing radioactive material. Then, the surface of the container or device is sprayed with metal or ceramics so as to cover the radioactive contaminants or cracks, and a sealing material such as a resin compound or glass is applied on the sprayed coating to seal the sprayed pores. Characterizing containment method. 2. The containment method according to claim 1, wherein the surface of the object to be coated is roughened by sand feeding or the like before the metal or ceramic is sprayed.