• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2005년도 Proceedings of The 6th korea-china joint workshop on nuclear waste management
• /
• pp.300-315
• /
• 2005

Recently plasma surface-cleaning or surface-etching techniques have been focused in the respect of decontamination of spent or used nuclear parts and equipment. In this study decontamination rate of metallic cobalt surface was experimentally investigated via its surface etching rate with a $CF_4-O_2$ mixed gas plasma and metallic surface wastes of cobalt oxides were simulated and decontaminated with $NF_3$ - Ar mixed gas plasma. Experimental results revealed that a mixed etchant gas with about $80{\%}\;CF_4-20{\%}\;O_2$ gives the highest reaction rate of cobalt disk and the rate reaches with a negative 300 DC bias voltage up to $0.43\;{\mu}m$/min at $380^{\circ}C$ and $20{\%}\;NF_3-80\%$ Ar mixed gas gives $0.2\;{\mu}m$/min of reaction rate of cobalt oxide film.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 2005년도 추계학술발표회
• /
• pp.203-204
• /
• 2005

• 자원리싸이클링
• /
• 제22권4호
• /
• pp.12-21
• /
• 2013

E-waste(폐전기전자기기, WEEE)는 많은 종류의 금속을 함유한 유가물과 유해물의 복합혼합물로 자원의 유효이용과 환경부하저감을 위해 리싸이클링 처리가 필수로 되어 있다. 특히 최근 레어메탈의 공급제약문제 등으로 도시광산자원 중에서 E-waste의 비중이 높아지고 있다. 한편, E-waste의 리싸이클링산업에 있어서 E-waste의 경제적 가치의 파악은 매우 중요하다. 이와 같은 관점에서 본보에서는 E-waste를 대형가전, 소형가전, 휴대전화기 및 PCB(전자인쇄회로기판, 기판)로 분류해서 경제적 가치를 논하였다.

• 한국광물학회지
• /
• 제27권4호
• /
• pp.207-222
• /
• 2014

폐-광석으로부터 금속구리분말을 회수하기 위하여 더미 미생물용출, Fe 제거와 전기분해실험을 수행하였다. Cu가 0.034% 함유된 폐-광석시료에 대하여 더미 용출실험을 수행한 결과, Cu 용출률은 박테리아 용출-용액에서 61%, 황산 용출-용액에서 62%로 나타났다. Fe를 효과적으로 제거하기 위하여 더미 용출-용액에 NaOH, $H_2O_2$ 및 $Ca(OH)_2$를 각각 적용한 결과 $H_2O_2$가 가장 효과적인 Fe 제거제로 선정되었다. 전해질 용액을 준비하기 위하여 $H_2O_2$를 더미 용출-용액에 처리한 결과 박테리아 용출-용액에서 Fe가 99%, 황산 용출-용액에서 60%로 제거된 반면에 Cu 제거율은 각각 5%와 7%로 나타났다. 이 용액에 대하여 전기분해 실험을 수행한 결과 Cu 회수율이 박테리아 용출-용액에서 98%, 황산 용출-용액에서 76%로 나타났다. 모수석 형태의 금속구리분말이 양쪽 용출-용액에서 회수되었다.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2004년도 학술논문집
• /
• pp.117-118
• /
• 2004

국내 TRIGA Mark II&III 및 우라늄 변환시설 해체시 다량의 금속폐기물 발생이 예상되며, 현재 이러한 저준위 방사성 금속폐기물을 처리, 재활용하는 기술들에 대한 연구가 국$\cdot$내외적으로 활발히 수행 중에 있다. 이에 본 연구에서는 해체시 발생하는 금속폐기물의 효율적인 감용 및 재활용에 관한 국내외 처리 기술을 검토하여 국내 TRIGA Mark II&III 및 우라늄 변환시설에서 발생하는 해체 금속폐기물의 처리 방안을 수립하기 위한 정보를 제공하고자 한다.

• Nuclear Engineering and Technology
• /
• 제55권8호
• /
• pp.2889-2896
• /
• 2023

The waste acceptance criteria for heavy metals in mixed waste should be developed by reflecting the leaching behaviors that could highly depend on the repository design and environment surrounding the waste. The current standards widely used to evaluate the leaching characteristics of heavy metals would not be appropriate for the silo-type repository since they are developed for landfills, which are more common than a silo-type repository. This research aimed to explore the leaching behaviors of cementitious waste with Pb, Cd, and Sb metallic and oxide powders in an environment simulating a silo-type radioactive waste repository. The Toxicity Characteristic Leaching Procedure (TCLP) and the ANS 16.1 standard were employed with standard and two modified solutions: concrete-saturated deionized and underground water. The compositions and elemental distribution of leachates and specimens were analyzed using an inductively coupled plasma optical emission spectrometer (ICP-OES) and energy-dispersive X-ray spectroscopy combined with scanning electron microscopy (SEM-EDS). Lead and antimony demonstrated high leaching levels in the modified leaching solutions, while cadmium exhibited minimal leaching behavior and remained mainly within the cement matrix. The results emphasize the significance of understanding heavy metals' leaching behavior in the repository's geochemical environment, which could accelerate or mitigate the reaction.

• 대한기계학회논문집
• /
• 제19권12호
• /
• pp.3372-3381
• /
• 1995

An equilibrium analysis was carried out to determine principal species of heavy metals in waste incineration and their behaviors with variation of temperature, chlorine concentration, excess air ratio, and C/H ratio. The waste was assumed as a compound of hydrocarbon fuel, chlorine, and metals. Calculated results showed that the most important parameter to determine the principal species was temperature. Chlorine concentration also affected on mole fractions of the principal species. Generally principal species at high temperature were chlorides while there were some metals of which principal species were oxides. At low temperature mole fractions of the principal species increased, but at high temperature mole fractions of some metal species decreased. C/H ratio of the hydrocarbon fuel and excess air ratio had little effect on mole fractions of the metal species, compared to the temperature and chlorine concentration.

• 자원리싸이클링
• /
• 제13권2호
• /
• pp.47-53
• /
• 2004

알루미늄 폐드로스는 알루미늄 용해업체에서 발생되는 주요 폐기물 중 하나인데, 폐드로스에는 상당량의 금속 알루미늄이 잔류한다. 본 연구에서는 알루미늄 폐드로스 내에 잔류하는 금속 알루미늄을 회수하고자 폐드로스를 수산화나트륨 용액으로 침출하여 폐드로스 중의 잔류 알루미늄을 용액 상으로 침출, 분리시킨 다음. 침출용액 중에서 알루미늄 성분을 수산화알루미늄으로 제조하는 연구를 수행하였으며, 연구결과의 상용화를 위하여 시범생산라인을 건설하여 시운전하였다. 시범생산라인은 년간 1,000톤의 폐드로스를 처리하여 500톤의 수산화알루미늄을 생산할 수 있는 규모이다. 생산라인의 시운전 결과 연구 개발한 기술의 상용화 가능성을 확인할 수 있었으며, 시험생산한 수산화알루미늄은 수처리 응집제용으로 사용 가능하다고 판단된다.

• Nuclear Engineering and Technology
• /
• 제53권5호
• /
• pp.1491-1510
• /
• 2021

This work presents an illustration of Nagra's AMAC (Advanced Methodology for Activation Characterization) approach to the South Korean pressurized water reactor Kori-1 decommissioning. The results achieved are supported by the existing experience from the detailed AMAC applications to Swiss NPPs and are used not only for a demonstration of the applicability of AMAC to South Korean NPPs, but also for a first approximation of the activated waste volumes to be expected from Kori-1. A packaging concept based on the above activation characterization is also presented, using the AMAC algorithmic optimization software ALGOPACK leading to the minimum number of waste containers needed given the selected packaging constraints. Nagra's AMAC enables effective planning before and during NPP decommissioning, including recommendations for cutting profiles for diverse reactor components and building structures. Finally, it is expected to lead to significant cost savings by reducing the number of expensive waste containers, by optimizing a potential melting strategy for metallic waste as well as by significantly limiting the number of radiological measurements. All information about Kori-1 used for the purpose of this study was collected from publicly available sources.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2004년도 학술논문집
• /
• pp.32-42
• /
• 2004

Recently, plasma surface-cleaning or surface-etching techniques have been focused in respect of the decontamination of spent or used nuclear parts and equipment. In this study the removal rate of metallic cobalt surface is experimentally investigated via its surface etching rate with a $CF_4-o_2$mixed gas plasma. Experimental results reveal that a mixed etchant gas with about 80% $CF_4$-20% $O_2$ (molar) gives the highest reaction rate and the rate reaches 0.06 ${\mu}m$/min at $380^{\circ}C$ and ion-assisted etching dramatically enhances the surface reaction rate. With a negative 300 V DC bias voltage applied to the substrate, the surface reaction initiation temperature lowers and the rate increases about 20 times at $350^{\circ}C$ and up to 0.43 ${\mu}m$/min at $380^{\circ}C$, respectively. Surface morphology analysis confirms the etching rate measurements. Auger spectrum analysis clearly shows the adsorption of fluorine atoms on the reacted surface. From the current experimental findings and the results discussed in previous studies, mechanistic understanding of the surface reaction, fluorination and/or fluoro-carbonylation reaction, is provided.