Как выбрать гостиницу для кошек
14 декабря, 2021
Russia adheres to the principles of safe RAW management [18] , involving the following basic stages of the process:
1. Pretreatment
• collection
• segregation
• chemical adjustment
• decontamination.
2. Treatment
• volume reduction
• removal of radionuclides from the waste
• change of composition.
3. Conditioning
• solidification
• immobilization
• overpacking.
RAW is divided into categories based on its origin; its physical, chemical and biological properties; its state of aggregation; and level of activity. The different properties of different types of RAW make it necessary to use different RAW management technologies for different sorts of waste. In Russia, a number of technological methods have been developed to allow the optimal processing of RAW. The basic methods used for RAW processing [19] are presented in Table 10.5 and Fig. 10.5.
LRAW constitutes the majority of all RAW in Russia, with 90% of LRAW made up of aqueous solutions originating from (a) technological drains, which are produced at industrial and research centres, including medical and biological laboratories; and (b) decontamination drains from the decontamination of equipment and overalls. These aqueous solutions are highly varied in their chemical and radionuclide composition, and include such diverse forms as ions, dissolved complexes of organic substances, colloidal particles and micelles, suspended solids, and liquid emulsified oil products. Solid RAW includes different materials contaminated with radionuclides such as construction materials, dismantled equipment, spent filters and resin, corpses of experimental animals, and silts and soils from contaminated territories.
The basic aim of RAW treatment is to reduce the physical volume of the waste and to transfer this waste into a monolithic, chemically and mechanically stable form, suitable for long-term storage in containers.
RAW Type |
Processing methods |
|
Solid |
Combustible |
Combustion in furnaces on fire grates at 900°C, plasma treatment, thermochemical treatment, vitrification, acid decomposition |
Compactable |
Compaction at low and high pressure, super-compaction |
|
Metallic |
Compaction, melting |
|
Incombustible and non-compactable |
Direct placement into containers |
|
Liquid |
Organic combustible |
Combustion, joint combustion with SRAW, encapsulation in cement matrix |
Organic incombustible |
Absorption using powders and encapsulation in cement matrix, thermochemical treatment |
|
Liquid low salinity |
Purifying (concentration) by evaporation, by chemical precipitation, by absorption, by selective absorption, by a membrane separation process, by cementation |
|
Liquid high salinity |
Purifying by selective absorption, cementation, bituminization, vitrification |
|
Gaseous |
Trapping by absorption and through the use of chemical reagents |
Table 10.5 The basic methods for RAW processing |
10.5 Basic methods of RAW treatment at MosNPO ‘Radon’ [19].