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IEC 62321 국제표준화의 Projector Leader 수임에 의한 국가 경쟁력 강화
김재우(Kim Jae Woo),정재학(Jung Jaehak),이성익(Lee Seong-Ik),최은경(Choe Eun Kyung),명영찬(Myoung Young Chan),정남용(Cheong Nam-Yong) 표준인증안전학회 2012 표준인증안전학회지 Vol.2 No.2
Many electrical and electronic companies are realizing that they need to be able to identify materials containing hazardous substances. Thus, TC 111 working group 3 that developed test methods of hazardous substances was organized in the IEC. Korea has contributed to WG 3 by dispatching around 10 Korean experts since 2008. Particularly, NWIP(New Work Item Proposal) on the test method of phthalates that has been recently an issue in the international environmental regulation was proposed by Korean experts of WG 3 and approved officially by IEC TC 111 WG 3. As such the standardization of phthalates is now in progress and is expected to be published officially as international standard, IEC 62321-8 in 2015. Another successful example where Korean expert took on responsibility as a project leader is standardization of IEC 62321-3-2 by developing screening method for total bromine. In this paper, detailed processes of standardization of IEC62321-3-2 and IEC62321-8 under Korea s leadership will be reported with resulting positive effects of Korea national committee s aggressive participation in international standardization.
Phase Analysis of Uranium Oxides by XRD After Heat Treatment
Seonjin Kim,Joohyung Kim,Hyejin Son,Wonpyo Jeong,Seungyeon Choi,Sangjoon Ahn,Jaehak Cheong,Kwangheon Park 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2
Once discharged, spent nuclear fuel undergoes an initial cooling process within deactivation pools situated at the reactor site. This cooling step is crucial for reducing the fuel’s temperature. Once the heat has sufficiently diminished, two viable options emerge: reprocessing or interim storage. A method known as PUREX, for aqueous nuclear reprocessing, involves a chemical procedure aimed at separating uranium and plutonium from the spent nuclear fuel. This separation not only minimizes waste volume but also facilitates the reuse of the extracted materials as fuel for nuclear reactors. The transformation of uranium oxides through dissolution in nitric acid followed by drying results in uranium taking the form of UO2(NO3)2 + 6H2O, which can then be converted into various solid-state configurations through different heat treatments. This study specifically focuses on investigating the phase transitions of artificially synthesized UO2(NO3)2 + 6H2O subjected to heat treatment at various temperatures (450, 500, 550, 600°C) using X-ray Diffraction (XRD) analysis. Heat treatments were also conducted on UO2 to analyze its phase transformations. Additionally, the study utilized XRD analysis on an unidentified oxidized uranium oxide, UO2+X, and employed lattice parameters and Bragg’s law to ascertain the oxidation state of the unknown sample. To synthesize UO2(NO3)2 + 6H2O, U3O8 powder is first dissolved in a 20% HNO3 solution. The solid UO2(NO3)2 + 6H2O is obtained after drying on a hotplate and is subsequently subjected to heat treatment at temperatures of 450, 500, 550, and 600°C. As the heat treatment temperature increases, the color of the samples transitions from orange to dark green, indicating the formation of different phases at different temperatures. XRD analysis confirms that uranyl nitrate, when heattreated at 500 and 550°C, oxidizes to UO3, while the sample subjected to 600°C heat treatment transforms into U3O8 due to the higher temperature. All samples exhibit sharp crystal peaks in their XRD spectra, except for the one heat-treated at 450°C. In the second experiment, the XRD spectra of the heat-treated UO2 consistently indicate the presence of U3O8 rather than UO3, regardless of the temperature. Under an oxidizing atmosphere within a temperature range of 300 to 700°C, UO2 can be oxidized to form U3O8. In the final experiment, the oxidation state of the unknown UO2+X was determined using Bragg’s law and lattice parameters, revealing that it was a material in which UO2 had been oxidized, resulting in an oxidation state of UO2.24.