Development Trend of Radwaste Characterization Technology for Safe Disposal

Seok-Ju Hwang,YoungHwan Hwang,Cheon-Woo Kim 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2

For the disposal of radioactive waste generated from nuclear power plants, characterization of radioactive waste is essential. For characterization, samples of radioactive waste are directly collected or an indirect method is used through X-ray, etc. Through indirect analysis, which is a non-destructive method, the density, filling height, homogeneity and inter structure of the waste container can be analyzed. Currently, foreign institutions are in the process of developing a technology to perform characterization of radioactive waste through indirect analysis. In particular, research on improving internal image accuracy through image analysis techniques, improving measurement methods and enhancing portability for field application is ongoing. Through the review of such technology development trends, it will be utilized in the development of domestic radioactive waste disposal technolgy.

Review of Latest Radioactive Waste Monitoring Technology

Seok-Ju Hwang,Younghwan Hwang,Jisoo Yoon,Jung-Kwon Son 한국방사성폐기물학회 2024 한국방사성폐기물학회 학술논문요약집 Vol.22 No.1

Review on the Validation of Activated Material Modeling Analysis

Seok-Ju Hwang,Younghwan Hwang,Jisoo Yoon,Jung-Kwon Son 한국방사성폐기물학회 2024 한국방사성폐기물학회 학술논문요약집 Vol.22 No.1

Development Technology of Concrete Container Characteristic Evaluation

Seok-Ju Hwang,Younghwan Hwang,Mihyun Lee,Jung-Kwon Son,Changgyu Kim 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2

At domestic nuclear power plant, concrete containers are stored to store waste generated before waste acceptance criteria (WAC) was established. Concrete container store concentrated waste liquid and waste resin. In order to disposal radioactive waste to a disposal site, it is necessary to conduct a characteristic evaluation inside the waste to check whether it satisfies the WAC. Two types of concrete containers are stored: round and square. The round type is filled with one 200-liter drum, and the square type is filled with four 200-liter drums. In the case of a round shape, the top lid is fastened with bolts, so it is possible to collect samples after opening the top lid without the need for additional equipment. However, in the case of a square shape, there is no top lid, and concrete is poured to cure the lid, so the separate equipment for characteristic evaluation is required. It is necessary to install a workstation for sample collection on the top of the concrete container, equipment for coring the top of the concrete container, and a device to prevent concrete dust scattering. Currently, the design of equipment for evaluating the characteristics of concrete containers has been completed, and equipment optimization through mock-up test will be performed in the future.

Review of Overseas Radwaste Disposal Site WAC

Seok-Ju Hwang,Younghwan Hwang,Jisoo Yoon,Jung-Kwon Son 한국방사성폐기물학회 2024 한국방사성폐기물학회 학술논문요약집 Vol.22 No.1

Convective heat transfer characteristics of nanofluids under laminar and turbulent flow conditions

Younghwan Kwon,Yonghyeon Cho,Chengguo Li,Seongir Cheong,Yujin Hwang,Jaekeun Lee,Daeseung Hong,Seongyong Moonb 한국물리학회 2009 Current Applied Physics Vol.9 No.2

To investigate the effect of nanofluids on convective heat transfer, an experimental study was performed through a circular straight tube with a constant heat flux condition in the laminar and turbulent flow regime. Stable nanofluids, which were water-based suspensions of alumina and amorphous carbonic nanoparticles, were prepared by two- and one-step methods. The effects of thermal conductivity and supernatant nanoparticles of the nanofluids on convective heat transfer were investigated under different flow regimes. In alumina nanofluids containing 3 vol% of suspended particles, the increment of thermal conductivity and convective heat transfer coefficient was 8% and 20%, respectively. For amorphous carbonic nanofluids, the thermal conductivity was similar to that of water, and the convective heat transfer coefficient increased by only 8% in laminar flow. In a comparison of thermal conductivity and convection, the enhancement of the convective heat transfer was much higher than that of the thermal conductivity of nanofluids. The movements of nanoparticles enhanced the convective heat transfer at the entrance region. To investigate the effect of nanofluids on convective heat transfer, an experimental study was performed through a circular straight tube with a constant heat flux condition in the laminar and turbulent flow regime. Stable nanofluids, which were water-based suspensions of alumina and amorphous carbonic nanoparticles, were prepared by two- and one-step methods. The effects of thermal conductivity and supernatant nanoparticles of the nanofluids on convective heat transfer were investigated under different flow regimes. In alumina nanofluids containing 3 vol% of suspended particles, the increment of thermal conductivity and convective heat transfer coefficient was 8% and 20%, respectively. For amorphous carbonic nanofluids, the thermal conductivity was similar to that of water, and the convective heat transfer coefficient increased by only 8% in laminar flow. In a comparison of thermal conductivity and convection, the enhancement of the convective heat transfer was much higher than that of the thermal conductivity of nanofluids. The movements of nanoparticles enhanced the convective heat transfer at the entrance region.

Effect of materials structure and composition on properties of siloxane-containing hydrogels

Younghwan Kwon,Minhyeon Song,Yong Gu Hwang,Seung Hyun Chang,Won Ji Hong 한국물리학회 2008 Current Applied Physics Vol.8 No.3,4

Properties of siloxane-containing hydrogels were investigated with formulations of siloxane-containing monomer (TRIS) and/or poly(dimethylsiloxane) macromers with hydrophilic monomers such as 2-hydroxyethyl methacrylate (HEMA) and N,N-dimethyl acrylamide (DMA). Phase separation behavior of siloxane-containing hydrogels was found to be affected mainly by compositions of siloxanebased hydrophobic/hydrophilic monomers. Properties of siloxane-containing hydrogels were investigated with formulations of siloxane-containing monomer (TRIS) and/or poly(dimethylsiloxane) macromers with hydrophilic monomers such as 2-hydroxyethyl methacrylate (HEMA) and N,N-dimethyl acrylamide (DMA). Phase separation behavior of siloxane-containing hydrogels was found to be affected mainly by compositions of siloxanebased hydrophobic/hydrophilic monomers.

사면안정 대책공법 안내시스템 개발

지영환(Younghwan Ji),허태성(Taesung Hur),황영철(Yeongcheol Hwang),차영환(Yeonghwan Tscha),이승호(Seungho Lee) 한국정보과학회 2007 한국정보과학회 학술발표논문집 Vol.34 No.2C

상지대학교 ‘낙석 및 산사태 방재연구단’에서는 ‘건설교통부 지역기술혁신사업’의 일환으로 사계절 낙석과 산사태 위험에 노출되어 있는 강원지역의 주요 도로 사면에 대한 재해를 저감하기 위하여 통합 사면관리기술, 광역산사태 저감기술 및 사면 안정성증대기술을 개발하고 있다. 본 논문은 강원지역의 최근 5년간 시공된 주요 사면별 178종의 애트리뷰트들의 정보를 Database화하고 이를 활용하여 시공 예정인 특정 사면과 환경조건이 유사한 사면에 적용하였던 공법들과 이에 따른 유지보수 내역과 안정성 등의 정보를 제공하는 사면정보 검색시스템의 설계와 구현에 관한 것이다. 검색의 효율성을 위해 18종의 중요 애트리뷰트들을 선정하고, 이들을 선택형과 기재형으로 분류한 후, 공법들간의 유사도(일치도)를 측정하는 방안을 도입하였다.

디지털 트윈 내 복합추론을 위한 협력적 모델 추론 방식

정영환(Younghwan Jeong),최원기(Won Gi Choi),황태민(Taemin Hwang),이진영(Jinyoung Lee),이상신(Sangshin Lee) 대한전자공학회 2024 대한전자공학회 학술대회 Vol.2024 No.6

Digital twins, bridging the realms of reality and virtuality while harnessing simulations such as AI, get significant attention for their predictive capabilities in foreseeing the future. However, they encounter challenges in scalability due to simplistic predictions in specific domains. This paper proposes Multi-client collaborative inference scheme (MCCIS), a collaborative model training approach aimed at harmonizing and accelerating heterogeneous simulations within digital twins. The proposed method constructs a global fusion model based on similar pretrained models and trains it to excel in terms of training and inference costs, as well as accuracy, compared to conventional distributed model training methods.

이용자의 성격특성과 접근성이 디지털 리터러시에 미치는 영향에 관한 연구

문영환(Younghwan Moon),홍아름(Ah Reum Hong),황준석(Jun Seok Hwang) 한국정보사회학회 2017 정보사회와 미디어 Vol.18 No.2

본 연구는 이용자의 디지털 리터러시에 개인의 성격특성과 접근성이 미치는 영향 및 구조적 관계를 분석하기 위해 진행되었다. 정보격차의 원인으로 이용자의 디지털 리터러시를 보았으며 이에 접근성과 이용자 개인성격특성의 직간접적인 효과들을 구조방정식 모델을 통해서 검증하였다. 연구결과는 다음과 같다. 첫째. 이용자의 개인 성격특성은 디지털 리터러시와 접근성에 대해서 직접적인 영향을 미치는 것으로 나타났다. 둘째. 이용자의 접근성은 디지털 리터러시에 직접적인 영향을 미친다. 연구결과 기기 접근성, 서비스 접근성 모두 디지털 리터러시의 전 영역에 유의미한 직접효과를 미치는 것을 확인할 수 있다. 셋째. 이용자의 성격특성은 접근성을 매개하여 디지털 리터러시에 간접적인 영향을 미친다. 따라서 이용자 맞춤형 디지털 리터러시 교육을 위해서 성격특성에 따른 정책적 접근이 필요하다. This research intended to analyze the influences of digital divide on digital literacy, focusing on character trait and accessibility. The researcher confirmed the importance of digital literacy on digital divide, and investigated the relationship between factors of digital literacy (Skill, Usage, Participation) and external factors(personal characteristic trait, device and service accessibility) through structural equation. Research results are as follows. First. Users" individual characteristic trait appeared to directly influence digital literacy and both accessibility. Second. Users" accessibility directly influenced digital literacy. According to the research result, it was confirmed that both device accessibility and service accessibility directly influenced the whole area of digital literacy significantly. Third. Users" characteristic trait indirectly influenced digital literacy. In respect of Skill of digital literacy, it was confirmed that indirect effect was bigger than direct effect on all of characteristic trait, also, indirect effect of characteristic trait appeared bigger than indirect effect, on openness, faithfulness, and favorableness, in Participation. Nevertheless direct effect of characteristic trait on digital literacy was limited, as above, however it implied that characteristic trait was an important variable in digital divide problem, considering indirect effect. Also, mediated effect of accessibility should be considered as an important variable.