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Magnetite Dissolution by Copper Catalyzed Reductive Decontamination
김선병,박상윤,최왕규,원휘준,박정순,서범경 한국방사성폐기물학회 2018 방사성폐기물학회지 Vol.16 No.4
Hydrazine based reductive dissolution applied on magnetite oxide was investigated. Dissolution of Fe(Ⅱ) and Fe(Ⅲ) from magnetite takes place either by protonation, surface complexation, or reduction. Solution containing hydrazine and sulfuric acid provides hydrogen to break bonds between Fe and oxygen by protonation and electrons for the reduction of insoluble Fe(Ⅲ) to soluble Fe(Ⅱ) in acidic solution of pH 3. In terms of dissolution rate, numerous transition metal ions were examined and Cu(Ⅱ) ion was found to be the most effective to speed up the dissolution. During the cycle of Cu(I) ions to Cu(Ⅱ) ions, the released electron promoted the reduction of Fe(Ⅲ) and Cu(Ⅱ) ions returned to Cu(I) ion due to the oxidation of hydrazine. In the experimental results, the addition of a very low amount of cupric ion (about 0.5 mM) to the solution increased the dissolution rate about 40% on average and up to 70% for certain specific conditions. It is confirmed that even though the coordination structure of copper ions with hydrazine is not clear, the Cu(Ⅱ)/H+/N2H4 system is acceptable regarding the dissolution performance as a decontamination reagent.
The Status and Prospect of Decommissioning Technology Development at KAERI
문제권,김선병,최왕규,최병선,정동용,서범경 한국방사성폐기물학회 2019 방사성폐기물학회지 Vol.17 No.2
The current status and prospect of decommissioning technology development at KAERI are reviewed here. Specifically, this review focuses on four key technologies: decontamination, remote dismantling, decommissioning waste treatments, and site remediation. The decontamination technologies described are component decontamination and system decontamination. A cutting method and a remote handling method together with a decommissioning simulation are described as remote dismantling technologies. Although there are various types of radioactive waste generated by decommissioning activities, this review focuses on the major types of waste, such as metal waste, concrete waste, and soil waste together with certain special types, such as high-level and high-salt liquid waste, organic mixed waste, and uranium complex waste, which are known to be difficult to treat. Finally, in a site remediation technology review, a measurement and safety evaluation related to site reuse and a site remediation technique are described.