Behavior of radioactive cesium during direct melting treatment of decontamination waste with and without Cl-containing additives
| Autor: | Hidetoshi Kuramochi, Masaki Takaoka, Nagata Toshimi, Kohei Ito, Masahiro Osako, Hitoshi Koshida, Kazuko Yui, Hiroshi Suzuki, Koichi Noda, Yoshimoto Yuichi, Naoko Yoshimoto |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
021110 strategic
defence & security studies Strontium Environmental Engineering Volatilisation General Chemical Engineering Inorganic chemistry 0211 other engineering and technologies chemistry.chemical_element 02 engineering and technology Human decontamination 010501 environmental sciences Raw material Alkali metal 01 natural sciences chemistry Fly ash Environmental Chemistry Leaching (metallurgy) Safety Risk Reliability and Quality Thermal analysis 0105 earth and related environmental sciences |
| Zdroj: | Process Safety and Environmental Protection. 143:186-195 |
| ISSN: | 0957-5820 |
| DOI: | 10.1016/j.psep.2020.06.032 |
| Popis: | We investigated the behavior of radioactive cesium (r-Cs) in a direct melting system (DMS), in which decontamination waste (DW) is thermally converted to slag and fly ash. Most of the r-Cs (98.4 %) in the DW was volatilized in the melting furnace and solidified in fly ash (FA), resulting in slag with low radioactivity. To produce even cleaner slag, we added two Cl-containing additives (CaCl2 and polyvinyl chloride) to promote r-Cs volatilization as r-CsCl gas. The former was more effective than the latter. This difference between different additives was investigated by thermal analysis. The partitioning behavior of other elements such as strontium (Sr) was also investigated. We measured the leachability of r-Cs, alkali metals, and Sr from the slag and FA to evaluate their safety. Our results showed that the slag can be used as a construction material. However, the r-Cs and Sr leachability from FA increased with increased presence of Cl in the feedstock. Finally, the effect of the two additives on the partitioning and leaching behaviors of r-Cs and Sr was investigated based on their chemical forms in the DMS as predicted by a thermodynamic equilibrium calculation. |
| Databáze: | OpenAIRE |
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