JPH0454918B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a blasting material suitable for decontaminating contaminated waste generated from nuclear material handling facilities etc. by surface polishing, although it is not particularly limited. More specifically, it relates to blasting pellets made by combining dry ice or ice particles with various fine abrasive materials for sandblasting.

[Prior Art] In the field of nuclear power, extremely important is placed on decontamination technology for contaminated waste generated from nuclear material handling facilities. If efficient decontamination technology is established, it will be possible to decontaminate highly contaminated waste to low levels and make subsequent handling easier.
This is because contaminated materials or equipment can be decontaminated and reused effectively, and the amount of nuclear contaminated waste can be reduced.

Conventional decontamination techniques for equipment and components contaminated with nuclear materials include cleaning methods using alcohol and detergents, hot water jet methods that spray hot water at high speed,
A sandblasting method in which the surface is polished by spraying an abrasive such as silica sand, alumina, or iron powder with compressed air.
Alternatively, ice blasting methods using crushed granular ice instead of these abrasive materials have been used. Another method is to use dry ice instead of ice.

[Problems to be solved by the invention] However, these methods generate a large amount of secondary waste (cleaning agents, abrasives, water, etc.) after decontamination, and therefore require secondary waste processing equipment. This has major drawbacks, such as high processing costs and the need for installation space for processing equipment.

In particular, decontamination work using the cleaning method has the drawback of requiring a large number of workers and taking a long time. In addition, in the case of ice blasting, the secondary waste is liquid, so it is relatively easy to handle, but ice particles, which are the blasting material, have a smaller specific gravity and lower hardness than sandblasting materials, so they are less effective at decontamination. There were major problems in terms of decontamination performance, such as low decontamination and high consumption of blasting material. Similar drawbacks occurred when dry ice was used as the blasting material.

The purpose of the present invention is to eliminate the drawbacks of the prior art as described above, to achieve high decontamination efficiency, and to significantly reduce the amount of secondary waste generated, thereby reducing the number of personnel required for decontamination. An object of the present invention is to provide a new blasting pellet that can significantly reduce the time required.

[Means for Solving the Problems] The present invention, which achieves the above objects, uses dry ice or ice granules adjusted to an appropriate particle size as the main material, and silica sand and alumina powder are coated on the surface of the dry ice or ice granules. These blasting pellets have a structure in which various fine sandblasting abrasive materials such as iron powder are adhered and fixed.

[Operation] Blasting pellets having such a structure can be used in the same equipment as conventional ice blasting materials. Unlike dry ice alone or ice alone, these blasting pellets have an abrasive added to them, which increases their specific gravity and hardness, allowing them to exhibit high decontamination performance.

In particular, when dry ice is used as the main material, it vaporizes immediately after decontamination, making it possible to minimize the amount of secondary waste generated.

Since the outside of these blasting pellets is covered with an abrasive material for sandblasting, the abrasive material effectively hits the surface of the object to be decontaminated during decontamination, increasing the decontamination efficiency. Furthermore, by fixing the sandblasting abrasive only to the outside, the amount of sandblasting used can be kept to a minimum, reducing the amount of nuclear-contaminated waste while maintaining a sufficiently high decontamination efficiency.

[Example] Hereinafter, the present invention will be explained in more detail based on the drawings. FIG. 1 is an enlarged explanatory view showing one embodiment of a blasting pellet according to the present invention. This blasting pellet 1 has an abrasive-covered structure in which a sandblasting abrasive 3 is adhered and fixed to the surface of dry ice or ice granules 2, which is the main material. The abrasive material 3 used here is not particularly limited, but may be one conventionally used as an abrasive material for sandblasting, such as silica sand, alumina powder, or iron powder. Other powders can also be used as long as they are powders with high hardness and high specific gravity. Further, the particle size of the dry ice or ice particles 2 and the abrasive material 3, which are the main materials, may be appropriately determined depending on the structure and material of the object to be decontaminated, the contamination status, etc.

Such blasting pellets can be easily manufactured by pulverizing solids obtained through a normal dry ice manufacturing process or ice making process to an appropriate particle size, and then adding an abrasive and stirring and mixing. Can be done.

Now, the blasting pellets according to the present invention can be used in the same apparatus and method as in the conventional ice blasting method. When the main material is dry ice, it vaporizes immediately after processing, so it has the great feature that the amount of secondary waste generated is extremely small. In addition, dry ice has a higher specific gravity than normal ice, and since it is covered with an abrasive material for sandblasting, there is a highly hard abrasive material on the outer surface, making it harder than dry ice alone and also having a higher specific gravity. Therefore, the decontamination efficiency will be significantly increased. Even when the main material is ice, since it contains an abrasive for sandblasting, it has a higher specific gravity and hardness than normal ice blasting materials, which improves the decontamination effect and reduces the consumption of blasting pellets. In this case, the secondary waste generated in the decontamination work is mainly liquid, and the amount of solid waste is extremely small, so waste treatment is relatively easy.

[Effects of the Invention] As described above, the present invention is a pellet in which a finer abrasive material for sandblasting is adhered and fixed to the surface of dry ice or ice granules, which are the main materials. The specific gravity and hardness are higher than in the case of
This method has excellent effects in that decontamination performance is greatly improved and the number of personnel and time required for decontamination work can be significantly reduced.

In particular, when dry ice is used as the main material, it vaporizes immediately after decontamination, resulting in very little secondary waste, making waste disposal extremely easy. Furthermore, even when ice is used as the main material, the secondary waste in decontamination work is mainly liquid waste, so it is relatively easy to dispose of it.

Further, in the present invention, since the outside is covered with an abrasive material for sandblasting, the highly hard abrasive material hits the surface of the object to be decontaminated during decontamination, increasing the decontamination efficiency.
In addition, since the abrasive material for sandblasting is attached only to the outside, unlike when it is uniformly dispersed inside, the amount used can be kept to a minimum, achieving sufficiently high decontamination efficiency and reducing the amount of nuclear-contaminated waste. It has an excellent effect of reducing

By using such blasting pellets, it can be used to decontaminate metals and plastics contaminated with nuclear fuel materials inside cells or α-holes, or to remove surface-contaminated parts during decommissioning. This method has the advantage that it is possible to carry out staining work in a short time and efficiently, and that the inside of a glove box contaminated with plutonium, uranium, etc. can be decontaminated and reused.

[Brief explanation of the drawing]

FIG. 1 is an enlarged explanatory view showing one embodiment of a blasting pellet according to the present invention. 1... Pellet for blasting, 2... Dry ice or ice granules, 3... Abrasive material for sandblasting.

Claims (1)

[Claims] 1 Blasting pellets made by adhering and fixing a finer abrasive material for sandblasting to the surface of the main material, dry ice or ice granules.