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Decontamination system for lower-level radioactive waste

What is wet decontamination?

To remove contamination on the products that are contaminated by the radioactive materials.

The Wet-blast Decontamination Systems

Wet-blasting decontamination system that we Macoho proposes are:

  1. A safe and clean environment
  2. A significant reduction of wastes

By doing so, we can contribute to the resource circulating type society by the following ways. 1) Reduction of low-level radioactive waste 2) Recycling of wastes.

Classification of wastes

Wet-blasting is effective for decontaminating low-level radioactive wastes.

Non-radioactive wasteNon-industrial waste
Industrial waste
Radioactive wasteLow-level radioactive waste
High-level radioactive waste

Current decontamination method and it's problem

1) Dry Blast・Working environment is bad due to dust, and the pollution spreads.
・A mass generation of secondary wastes (abrasives)
2) Chemical process・Decontaminated fluid treatment is costly and time-consuming.
・Unsuitable for focal decontamination.
3) Wet Blast・Waste water treatment is required.
・A mass generation of secondary wastes (abrasives)

Problems and solutions for wet-blasting decontamination

Although it is known that wet-blasting treatment is a safe processing method and does not generate dust, it has been pointed out that some problems such as generation of secondary waste due to fracture of particles, weak in processing power, and requirement of waste water facility occurs.

Problems and solutions for wet-blasting decontamination

Special stainless steel abrasives

G10
g10 sem
Name: GH0.10-0.20
Material: High hardened stainless steel
Shape: Grit shape
Hardness: HV750
(Cutwire SUS304 is around HV200)

Feature

  1. It has 1.5 times more cutting ability power than the original abrasives (Alumina abrasives of ceramics series) *Figure 1
  2. Abrasion and consumption are extremely small, due to hard particles. *Figure 2
  3. Waste amount can be decreased more than 10 times, compared to original abrasives.
  4. Retrieve it by using an iron powder collection unit, and do away with it as valuables.

Processing power of special stainless abrasives -figure 1

Processing power of special stainless abrasives.
  • Processing conditions
  • Work piece : Stainless steel
  • Air pressure : 0.2MPa

Consumption percentage of special stainless abrasives -Figure 2

Consumption percentage of special stainless abrasives.
  • Processing conditions
  • Work : Carbide
  • Air pressure : 0.5MPa
  • *Accelerating tests of abrasive consumption.

Closed system

Closed system

Feature

  • 1) Iron powder retriever as well as a sludge recovery unit collect abrasive particles and remove residues.
  • 2) The water after removal is returned to the cell to reuse it as water-rinse for the work piece.

*At the exchange of original water during an equipment maintenance, we recommend the usage of a drum dryer etc. for the evaporation to dryness.

Examples of associated equipment (WFB-112-R)

Macoho Decontamination System, the low-level radioactive waste can be decontaminated
safely and quickly.

Macoho Decontamination System 1
Macoho Decontamination System 2

Please click here for information on facility cleaning