Analysis of the Plasma Recycling Process of Radioactive Waste

Keywords

radioactive waste, plasma processing, plasmochemical reactor, arc plasmatron, radiation safety, slag compound

How to Cite

Semerak, M., Lys, S., & Kovalenko, T. (2019). Analysis of the Plasma Recycling Process of Radioactive Waste. Nuclear and Radiation Safety, (1(81), 23-29. https://doi.org/10.32918/nrs.2019.1(81).04

Abstract

The possibility of the plasma processing of low-level or intermediatelevel radioactive wastes in the reactor equipped with arc plasmatrons is shown. The reactor design for the plasma processing of the radioactive wastes that allows promoting the efficiency of the plasma processing of the radioactive wastes (RAW) by the increasing of the speed and the intensity of the plasma pyrolysis is proposed. The various methods for RAW preparation, dosage and supply into the plasmochemical reactor have been investigated. The waste which is supplied to the reactor can be in various aggregate states (solid, liquid or gaseous) depending on which different kinds of preparation, dosage, and supply of RAW materials to the plasmochemical reactor are used. The solid waste must be ground for increasing of the phase separation surface. The degree of grinding of the wastes depends on their further reprocessing. The reactor allows processing of the mixed-type radioactive waste, which includes both combustible and non-combustible components. The wastes can be packed or ground up. The selected technological regimes should provide temperature from 1500 °C in the melting chamber to 250 °C in the upper part in the pyrogas exit zone to prevent the flow-out of volatile compounds of a series of radionuclides and heavy metals from the furnace and to process the waste and merge slag melt without adding of fluxes. The fused slag is a basaltiform monolith, where the content of aluminum oxide reaches 28%; silicon oxide up to 56%; sodium oxide from 2.5 to 11 %. The resulting radioactive slag is extremely resistant to the chemical influence. The pyrogas produced in the shaft furnace will have a heating value of about 5 MJ/nm3. This allows, after initial heating by plasmatron, maintaining the required temperature in the combustion chamber due to the heat released during combustion of the pyrogas, when the plasma heating source is switched off, and burning the resin and soot effectively. It is proved that the plasma technology for RAW reprocessing allows a significant reduction in waste volumes and waste placement for long-term storage with the most efficient use of storage facilities.

https://doi.org/10.32918/nrs.2019.1(81).04

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