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        검색결과 4

        1.
        2023.05 구독 인증기관·개인회원 무료
        Wolsong unit 1, the first PHWR (Pressurized Heavy Water Reactor) in Korea, was permanent shut down in 2019. In Korea, according to the Nuclear Safety Act, the FDP (Final Decommissioning Plan) must be submitted within 5 years of permanent shutdown. According to NSSC Notice, the types, volumes, and radioactivity of solid radioactive wastes should be included in FDP chapter 9, Radioactive Waste Management, Therefore, in this study, activation assessment and waste classification of the End shield, which is a major activation component, were conducted. MCNP and ORIGEN-S computer codes were used for the activation assessment of the End shield. Radioactive waste levels were classified according to the cooling period of 0 to 20 years in consideration of the actual start of decommissioning. The End shield consists of Lattice tube, Shielding ball, Sleeve insert, Calandria tube shielding sleeve, and Embedment Ring. Among the components composed for each fuel channel, the neutron flux was calculated for the components whose level was not predicted by preliminary activation assessment, by dividing them into three channel regions: central channel, inter channel, and outer channel. In the case of the shielding ball, the neutron flux was calculated in the area up to 10 cm close to the core and other parts to check the decrease in neutron flux with the distance from the core. The neutron flux calculations showed that the highest neutron flux was calculated at the Sleeve insert, the component closest to the fuel channel. It was found that the neutron flux decreased by about 1/10 to 1/20 as the distance from the core increased by 20 cm. The outer channel was found to have about 30% of the neutron flux of the center channel. It was found that no change in radioactive waste level due to decay occurred during the 0 to 20 years cooling period. In this study, activation assessment and waste classification of End Shield in Wolsong unit 1 was conducted. The results of this study can be used as a basis for the preparation of the FDP for the Wolsong unit 1.
        2.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 인쇄회로기판(PCB) 제조 시 에칭공정에서 발생되는 구리이온(Cu+2)을 고농도로 함유한 황산 폐에칭액을 NF 막분리법을 사용하여 에칭액 회수와 구리이온 처리를 효율적으로 수행하기 위한 NF 막여과 공정의 운전 조건을 설정하기 위한 기본 자료를 확보하는데 있다. 이를 위해 미국 Koch사의 SelRO MPS-34 4040 NF 막을 대상으로 구리이온을 고농도(5~25 g/L)로 함유한 모의 황산 폐에칭액의 회분식(dead-end) 나노여과 실험을 수행하여 투과 플럭스와 구리이온의 총괄 배제도를 측정하였다. 이 결과 황산용액에의 막 보관기간이 길수록, 황산용액의 pH가 낮을수록 황산에 의한 NF 막의 손상이 더 크게 발생하여 순수 투과 플러스가 증가하였다. 황산 폐에칭액의 투과 플럭스는 황산용액 내 구리이온의 농도가 증가할수록 막 표면에의 구리이온 농축(농도분극)의 증가에 따라 감소하였으며, 구리이온의 배제도는 구리이온의 농도가 높을수록, pH가 낮을수록, 황산용액 내의 막 보관기간이 길수록 낮아져 초기 37%에서 최소 15% 수준으로까지 감소하였다.
        4,000원
        3.
        2013.12 KCI 등재 서비스 종료(열람 제한)
        Waste recycling comes to the fore because of resources depletion and environmental pollution. ‘End-of-Waste (EoW)Criteria’ are reported to help improve recycling by determining when a waste ceases to be a waste, independently fromthe waste management option, and guarantee higher quality of secondary materials by environmental requirements of thesematerials. This approach can reduce consumption of natural resources and decrease the amount of waste sent for disposal.The aim of this study is to comprehensively review and analyze the current criteria on the End of Waste in foreigncountries. In addition, this paper suggests policy implications to promote more recycling and use of waste materials asresources by comparing domestic and foreign regulations. Based on the research, domestic EoW criteria need to be morecleared in the aspect to hazard assessment, ensuring a high level of environmental protection and solving legal uncertaintyhindering the development of the recycling sector.
        4.
        2013.04 KCI 등재 서비스 종료(열람 제한)
        This paper is a research on the end-of-waste (EoW) criteria of steel scrap. Government strengthens the management of the scrap recently, as pollution has been raised due to the improperly treated steel scrap. In this study, current status of steel scrap recycling was investigated through field survey in 2012, and classification and recycling standard of steel scrap in developed countries and institutions were investigated through literature survey in order to introduce optimal EoW criteria. As a result, contents of contaminants were selected as the most important recycling standards, and contents of contaminants in steel scrap was measured less than 0.5% in most of companies, but only one recycling company showed 10% of contaminants. EoW criteria for steel scrap was determined to be below 2% of contaminants. In this study, contaminants in steel scrap was defined as hazardous and pre-treated substances, considering the Korean industrial standards (KS). And EoW stage was determined by considering the regulation on resources and practices in field.