Material balance evaluation is an important measure to determine whether or not nuclear material is diverted. A prototype code to evaluate material balance has been developed for uranium fuel fabrication facility. However, it is difficult to analyze the code’s functionality and performance because the utilization of real facility data related to material balance evaluation is very limited. It is also restricted to deliberately implement various abnormal situations based on real facility data, such as nuclear diversion condition. In this study, process flow simulator of uranium fuel fabrication facility has been developed to produce various process data required for material balance evaluation. The process flow simulator was developed on the basis of the Simulink-SimEvents framework of the MathWorks. This framework is suitable for batch-based process modeling like uranium fuel fabrication facility. It dynamically simulates the movement of nuclear material according to the time function and provides process data such as nuclear material amount at inputs, outputs, and inventories required for Material Unaccounted For (MUF) and MUF uncertainty calculation. The process flow simulator code provides these data to the material balance evaluation code. And then the material balance evaluation code calculates MUF and MUF uncertainty to evaluate whether or not nuclear material is diverted. The process flow simulator code can simulate the movement of nuclear material for any abnormal situation which is difficult to implement with real process data. This code is expected to contribute to checking and improving the functionality and performance of the prototype code of material balance evaluation by simulating process data for various operation scenarios.

With the stabilization of Korea’s industrialization, it has become interested in the efficient use of rare metals, climate change and industrial environment and safety etc. It is thus making efforts to implement economic policies that address such issues. Therefore it is necessary to understand the demand, supply and use of metal materials. Since 2010, the Korean government has developed the integrated material flow methodology and has been trying to examine the demand, supply and use of metal materials. In 2013, the Korean government surveyed the material flow of chromium. Material flow analysis and environment emission of chromium were investigated 8 steps; (1) raw material, (2) first process, (3) Intermediate product, (4) End product, (5) Use/accumulation, (6) Collection, (7) Recycling, (8) Disposal. Chromium was used for stainless steel, alloy steel, coated sheets, refractory material and coating materials. Recycling was done mainly in use of stainless steel scrap. To ensure efficient use of chromium, process improvement is required to reduce the scrap in the intermediate product stage. In the process of producing of the products using chromium, it was confirmed that chromium was exposed to the environment. It requires more attention and protection against environment emission of chromium.

The basis of the cobalt demand analysis by use was established via the investigation and analysis of the cobalt materials flow, and the overall cobalt metal material and parts industry structure in Korea was examined to determine the cobalt material flow. The markets of the cobalt material for machinery were studied, including their interrelations, via market and study trends, and relevant plans were examined. The results of the study indicated that the advanced core technology for advanced industry and technology-intensive industry development is required to structurally innovate the parts materials and basic materials industries and to upgrade the catch-up industry structure to the new frontier structure.

A 2D axisymmetric numerical analysis was performed to study the characteristics of charge process inside solar thermal storage tank. The porosity and heat transfer coefficient of filler material as well as inlet velocity of heat transfer fluid are selected as simulation parameters. The porosity is varied as 0.2, 0.5, and 0.8 to account for the effect of filler granule geometry. Two levels of the heat transfer coefficient is adopted to assess the heat transfer between heat transfer fluid and filler material. The inlet velocity is varied as 0.00278, 0.0278, and 0.278m/s. As both of the porosity and the heat transfer coefficient increase, the discrepancy of the temperature distributions between the filler and heat transfer fluid decreases. As the inlet velocity increases, the penetration depth of the heat transfer fluid increases proportionally.

A 2D axisymmetric numerical analysis was performed to study the characteristics of charge process inside solar thermal storage tank. The interfacial area density and inertial resistance of filler material are selected as simulation parameters. The interfacial area density is varied as 800, 2000, and 4000 1/m. The inertial resistance is varied as 1, 3, and 5 1/m. When the interfacial area density increases from 800 to 4000 1/m, the discrepancy of the temperature distributions between the filler and heat transfer fluid decreases. As inertial resistance increases from 1 to 5, both of the temperature and fluid flow pattern changes considerably.

본 논문에서는 패시브 진돈제어시스템을 설치한 실대물 K형 철골브레이스 골조의 실험결과를 다루었다. 패시브 진동제어시스템은 점탄성물질을 이용하여 새롭게 개발된 댐퍼를 사용하였다. 이 실험모델의 진동제어 효율성을 확인하고 철골조 브레이싱의 진동반응특성을 조사하기 위하여 일련의 실험을 행하였다. 자유진동실험결과 댐퍼를 설치시 설치하지 않은 경우와 비교하여 3배정도의 진동제어능력을 나타냈다. 점탄성물질 난류댐퍼의 효율성은 진동실험에 의하여 확인되었다.

This thesis investigates vibration response characteristics of building frames in which dampers are installed. The frames belong to passively vibration-controlled. Structures which utilizes energy dissipation of mechanical dampers provided in the structure. In this thesis, a turbulent flow damper sealed by visco-elastic material was dealt with as the device of passive vibration control. To investigate the resisting force characteristics of the damper, harmonic vibratration tests were carried out. Based on the test results, a theoretical model of the damper resistance was presented and a method of identifying the model parameters was proposed. Shaking table tests of the frame with and without the dampers were carried out and the effectiveness of the damper was examined. The response of the frame with the dampers was reduced to 1/2 or 1/3 of the cases without the damper.

Since the Framework Act on Resource Circulation was enacted in 2018, the government should establish a National Resource Circulation Master Plan every 10 years, which defines mid- to long-term policy goals and directions on the efficient use of resources, prevention of waste generation and recycling of waste. In addition, we must set mid- to longterm and stepwise targets for the final disposal rate, recycling rate (based on sorted recyclable materials and recycled products), and energy recovery rate of wastes, and relevant measures should be taken to achieve these targets. However, the current industrial waste (IW) statistics have limitations in setting these targets because the final disposal rate and recycling rate are calculated as the ratio of the recycling facility input to the IW generation. In this study, the material flow from the collection stage to the final disposal of industrial waste was analyzed based on the generation of 2016, and the actual recycling amount, actual incineration amount, final disposal amount and their rates were calculated. The effect on the recycling, incineration and final disposal rates was examined by changing the treatment method of nonhazardous wastes from the factory and construction and demolition wastes, which were put in landfills in 2016. In addition, the variation of the waste treatment charge was investigated according to the change of treatment methods. The results of this study are expected to be effectively used to establish the National Resource Circulation Master Plan and industrial waste management policy in the future in South Korea.

National statistics of solid waste indicate that, although the amount of combustible wastes from household sectors is decreasing, the amount of waste that is buried in landfills increases each year. And the increasing rate of combustible wastes from industrial sectors is higher than the decreasing rate of combustible wastes from household sectors. Combustible waste, once screened, can be used as a potential energy resource contributing to resource circulation. Therefore, the objective of this study was to predict the amount of waste materials to be recovered and recycled by landfill mining and reclamation (LFMR), based on material flow analysis for four existing landfills. In this study, the landfills analyzed by material flow analysis were classified into types 1 to 4 by considering the status of the landfill and incineration situation. In order to perform material flow analysis, volume increase rate and bulk density were applied to the methodology employed in previous studies. In addition, material flow analysis software ‘STAN 2.0’ was used for the analysis. As a result of analyzing the average value of four landfills, the landfilled waste was classified as 93.9 m3 (73.7%) of combustible waste, 9.2 m3 (7.3%) of incombustible waste, and 24.3 m3 (19.1%) of soil matter. So, 73.7% can be incinerated or recovered by energy, 7.3% can be recycled as materials and reclaimed, and 19.1% can be recycled as landfill cover materials based on weight. The results of the material flow analysis carried out in this study are expected to be used to predict the amount of waste materials landfilled to be recovered by the material flow analysis during landfill mining processes.

과불화합물(PFCs, Perfluorinated compounds, 이하 과불화화합물) 등은 발암성, 생식독성, 생농축성 등을 가지고 특히 장거리 이동성을 가지고 있는 대표적인 잔류성 유기오염물질로 분류되고 있다. 스톡홀름 협약은 사전예방 원칙에 입각하여 잔류성 유기오염물질로부터 인간의 건강 및 환경 보호를 목적으로 하는 국제협약으로 ’04년 5월 발효되었다. 우리나라는 ’01년 10월 협약에 서명한 후 협약가입을 위해 잔류성유기오염물질의 배출 실태를 파악하고, 관련 법규를 제정하는 등 협약가입 준비 후, ’07년 2월에 가입하였다. 제4차 스톡홀름협약 당사국총회에서 과불화옥탄술폰산(PFOS)과 그 염류 등은 규제 대상물질로 등재(’09.4)하였으며, PFOS의 경우 용도에 따라 항구적 면제(Acceptable purpose), 특정면제(Specific Exemption), 사용제한하고 있으며 PFOA는 스톡홀름협약 POPs 검토위원회(POPRC)에서 위해성 검토 중으로 규제예고 되어 있다. 하지만 국내에서는 최근 아웃도어용품 등의 방수 기능성 제품에서 과불화화합물이 검출되어 논란이 일어나는 등, 과불화화합물의 위해성에 대한 관심이 증대되고 있으나, 과불화화합물 함유 제품 및 폐기물의 관리체계는 초기 정비 단계로, 스톡홀름 협약의 이행 및 과불화화합물 함유 제품 및 폐기물의 체계적 관리가 필요한 시점이다. 이에 본 연구에서는 스톡홀름협약 이행과 과불화화합물 함유폐기물을 적정처리를 위해 과불화화합물의 생산･사용･폐기 등 전과정 물질흐름분석을 통해 정량적인 자료를 확보하고, 물질과 제품의 사용용도별 폐기물 관리체계를 마련하였다.

우리나라에서는 자원순환기본법이 2015년 5월 29일에 공포되어 2018년 1월 1일부터 시행된다. 이 법에 따라 국가의 중장기 단계별 자원순환목표를 달성하기 위해 시･도와 산업폐기물 배출자를 대상으로 자원순환 성과관리제가 도입된다. 그 대상 주체는 최종처분율, 순환이용률의 목표의 이행계획을 제출하고 목표를 이행한 후에 그 이행실적을 보고해야 한다. 그러나 현재 국내에서는 폐기물 종류별, 업체별 순환이용률을 산정하기 위한 통계 기반이 미흡하다. 이 성과관리제의 성공적 실시를 위해서는 일선 업체별 폐기물 종류별 폐기물의 순환이용 실태 파악과 자원순환률 산정방법의 정립이 필요하다. 현재 ‘전국 폐기물 발생 및 처리현황’통계는 1차 재활용시설로 반입된 폐기물이 전량 재활용(순환이용)된 것으로 간주하여 재활용률을 산정하고 있다. 폐기물에 따라서는 1차 재활용시설에서 재생원료 및 재활용제품이 생산되는 경우도 있으나 여러 단계의 가공 및 정제 공정을 거쳐 재생원료나 재활용제품이 생산되는 경우도 있고, 이들 재활용 공정에서 이물질 제거와 공정손실이 발생하므로 이를 고려하여 재활용률(순환이용률)을 산정하여야 한다. 본 연구에서는 재활용 폐기물의 특성(물리･화학적, 함수율 등)과 재활용공정을 고려하여 그 유형을 구분하고, 회수된 재활용 폐기물의 전 공정에 대한 물질흐름을 조사하여 실제로 천연자원을 대체하여 순환 이용된 유효재활용률을 산정하였다. 현재 재활용률의 산정방법에 대하여 국제적으로 통일된 방법이 없기 때문에 재활용 폐기물의 투입 시점, 1차 해체･선별하여 재활용 원료로 판매하는 시점, 최종 재생원료 또는 재활용품 생산시설의 투입 시점과 최종 재생원료와 재활용품의 제조완료 시점으로 구분하여 다양한 관점에서 재활용률을 산정하여 이를 비교･분석하였다. 이를 통하여 물질재활용에 대하여 폐기물 특성과 재활용 공정을 고려하여 합리적인 물질재활용률 산정방법을 제시하였다. 또한 다양한 재활용 공정의 물질흐름 분석을 통하여 폐기물의 유효재활용률의 향상방안과 재활용 정책의 기초자료를 수집･제시하였다. 본 연구 결과는 향후 자원순환 성과관리제도의 정착에 크게 기여할 것으로 판단된다.

In order to promote the resource circulation and upcycling of waste refrigerators, it is necessary to analyze the material flow of recovered valuable resources and low-value residues after they are discharged. This study divided the flow of waste refrigerators into the five steps of discharge, collection, pretreatment, resource recovery, and sale/export/disposal and conducted material flow analysis (MFA) in each step. Waste refrigerators are treated via official (formal sectors, 65.6% of total amount) and unofficial (informal sectors, 34.4% of total amount) channels. Officially, waste refrigerators are collected through free collection by national and local governments, recovery by product producers and distributors, and waste collection·transportation·recycling companies and are recycled at public and private recycling centers. Unofficially, waste refrigerators are collected through junk shops and individual collectors. Waste refrigerators recycled in the formal sectors undergo pretreatment processes such as the disassembly, shredding, and separation and recovery of resources such as scrap irons, plastics, PCB (printed circuit board), cables, glasses, waste refrigerants, urethane, etc. Waste refrigerators recycled in informal sector treated through disassembly of the exterior, the shredding process by the excavators in illegal facilities and recovered waste refrigerants, plastics, glasses, scrap irons, copper, nickel silver, PCB, urethane, etc. MFA results show that in 2015, the amount of waste refrigerators collected from formal sectors reached 121,642 ton/year, the amount of recycling was 107,684 ton/year, and the amount of residues was 13,955 ton/year respectively. Thus, actual recycling rate per a waste refrigerator was estimated 88.15% in 2015. To promote the resource circulation and upcycling of waste refrigerators, it is necessary to find a way to improve the recycling of urethane, which accounts for 10.8% of the total weight of a refrigerator.

With the increase in food consumption, the amount of animal and plant residues in food manufacturing has continued to increase. In particular, the residues generated from food manufacturing industries have a high recycling value because they are generated in large quantities, are homogeneous, and their recycling costs are less than that of households or small restaurants. In this study, we selected industries that produce large amounts of homogeneous animal and plant residues, including manufacturers of animal oils and fats, vegetable oils and fats, starches and glucose or maltose, and conducted material flow analysis using statistical data, field surveys, and questionnaires. In the results of material flow analysis, the amount of raw materials used in the surveyed industries was 3,029,830 tons per year, and 8,487 tons of animal and plant residues were generated through manufacturing and processing. In addition, the import substitution effect of recycling byproducts from industries into animal feed or similar was estimated to be ₩847,007 million KRW per year.

The most common types of refrigerants used in automobiles today usually include HCFCs and HFCs, which have the potential of ozone depletion or the greenhouse effect. Although environmentally friendly refrigerants are being developed, there is still a lack of safety and high-cost problems for new refrigerants. This study was conducted to determine the flow of refrigerants from automotive air conditioners and examine their potential problems and a proper management plan. The number of automobiles manufactured, the number of automobiles in use, and end-of-vehicle flow were examined through available statistics and reports. The material flow of refrigerants has been determined by the life cycle of automobiles and the unit requirements of the refrigerants used in automobiles. Based on the results, in 2014, there were approximately 1,017 tons of refrigerants introduced from the manufacturing stage of automobiles, and about 395 tons of refrigerants leaked from the use stage. After the use stage, only 13 tons of refrigerants were delivered to treatment facilities and 195 tons were emitted into the atmosphere during the dismantling process. As a result, in South Korea in 2014, a large amount of refrigerants (590 tons) was estimated to have been leaked into the atmosphere from automotive air conditioners during the use and dismantlement stage. Several preventive measures for refrigerants should be properly enforced by introducing economic incentives as well as a monitoring system with strengthened laws and policies.

수은은 온도계, 혈압계, 치과용 아말감, 전지, 형광등과 의약품 등 많이 사용되고 산업적으로도 전기 스위치, 촉매 등으로 중요하게 사용된다. 수은은 증기 흡입 시 폐렴을 유발하고 중추신경계와 신장에 영향을 줄 수 있을 정도로 매우 위험하여 수은과 수은 화합물의 사용이 금지되거나 제한을 받고 있으며, 대체물질과 대체 공정의 개발을 위한 노력이 행해지고 있다. 최근 연이은 병원, 학교 등의 혈압계, 온도계의 수은 누출사고와 형광등 생산시설인 (주)남영전구 광주공장의 해체 및 철거 중 수은 누출로 인한 근로자의 수은 중독 및 환경오염 사고와 비철금속업체의 수은 폐기물 처리문제가 대두되었다. 전국 병원 2,500개소 설문조사 결과, 143개 병원에서 혈압 및 체온계의 약 4천여개(수은량 : 약 140 kg)가 회수와 폐기가 필요한 것으로 조사되었다. 또한 미나마타 협약에서 요구되는 수은 수출･입, 공급원 파악, 임시보관 및 유통･보관, 회수, 처리 등 단계별 수은의 회수, 유통, 관리에 대한 체계 구축이 미흡하다. 수은폐기물은 미나마타협약에 의하여 ‘수은 구성 폐기물’, ‘수은 함유 폐기물’, ‘수은 오염 폐기물’로 나눠지고 본 연구에서는 ‘수은 함유 폐기물과 오염 폐기물’의 수입, 유통, 회수, 폐기 등 전과정 단계별 흐름 분석을 통하여 수은의 국내 흐름을 파악하고 관련 법 제도의 문제점을 분석하고자 함에 있다. 또한 수은 관련 유통량을 조사하고 폐기물의 처리 공정을 파악하여 대상 물질, 원료 사용량, 시스템 경계 설정, 데이터 수집 및 분석, 계산과 검증 등의 절차를 걸쳐 물질수지에 근거하여 ‘물질흐름도’를 작성하여 도출하였다. 물질흐름분석을 보다 쉽게 활용하고 적용할 수 있도록 ‘물질흐름분석 소프트웨어(STAN 2.5)를 활용하여 공정 내의 데이터 유입과 유출을 Shankey diagram 형태로 표현하였다. 연구 결과, 원자재 수은의 국내 유통량은 2014년 기준 국내 유입량은 약 3톤(제조량: 1 ton, 수입량: 2 ton)으로 집계되고 수입된 수은은 대부분 형광램프 제조(2.01 ton), 시약(0.76 ton), 촉매(0.12 ton) 등의 용도로 사용된 것으로 나타났다. 회수량은 문헌 조사 결과 수은 함유 부산물 및 폐기물 관리를 위해 도입되는 시나리오별 두 가지 기준을 적용하여 회수 가능량을 추정하였다. 시나리오에 따라 27.3 ton/yr, 25.4 ton/yr으로 예측하였다. 원자재 수은의 국내 재고량은 대략 0.5 ton/yr으로 보인다.

In this study, the chemical flow of butadiene in the Korean chemical material industry was analyzed by chemical flow analysis. In addition, the atmospheric emissions estimation equation was calculated. The results of the product-specific material flow analysis showed that 1,450,076 tons of butadiene have been used in the domestic chemical material industry. Of that, 28.2% was used for SBR, 29% for BR, 21.2% for ABS, and 21.5% for the manufacture of other rubber products. In addition, butadiene has been used in the production of final products, such as automotive supplies and equipment, tires, shoes, and consumer electronics products. Among them, it was found that the major product at 39% in the production of tires. About 56.7 tons of butadiene found to have been emitted into the atmosphere by the calculated expression. The results of the regional analysis showed butadiene was treated in five cities and seven provinces, with the largest amount of butadiene used in Chungnam. The results of standard industrial classification showed that, among the 23 divisions of the standard industrial classification, butadiene flow in the manufacture of synthetic resins or other plastic materials was found to account for about 70% of the total.

Material flow analysis (MFA) of recycling material and of mercury from linear-type spent fluorescent lamps (SFLs was performed to estimate the material composition of the chain recycling process by an input-output approach. The recycling process system for linear-type SFLs was established using an end-cutting system, a hammer crusher, a screen separation system, a mercury distillation system, and an activated carbon adsorption component. From the results of the MFA of lineartype SFLs, 92% of materials used in linear-type SFLs such as glass, aluminum, and phosphor powder can be recycled. For MFA of mercury, the mercury content in the phosphor powder was the highest among material compositions tested and the total mercury amount in the recycling materials from 1 ton of SFLs was estimated to be 75.43 g. In the recycling process system for linear-type SFLs, the mercury amount in the vapor phase was analyzed and found to be 2228 mg in the endcutting system, 172 mg in the hammer crusher, and 2585 mg in the screen separation system. The total mercury amount in the vapor phase was estimated to be 4985 mg, which was only 6.22% of the total mercury amount emitted from the recycling process system. Hence, it was estimated that the MFA of the total mercury amount obtained from the vapor phase and the recycling materials of 1 ton of SFLs using the recycling process system was 80.175 g.

In this study, the recycling processes of construction and demolition waste (C&D waste) were analyzed, and its national recycling rate was determined using material flow analysis (MFA). Available statistical data provided by Ministry of Environment and Korea Environment Corporation were used for the MFA study. The collected data were carefully examined and validated by field investigations. System boundary for MFA covered from waste generation from construction sites to final disposal in 2013. The field investigation showed that recycled aggregate is produced through mechanical shredding, separation, and screening processes of C&D waste. The production efficiency (or process yield) was estimated to be approximately 81.2% on average. The foreign materials in the waste accounted for 18.8% by weight. The separated impurities were sent to recycling facilities, incineration facilities, or landfill sites, depending on the physicochemical characteristics. Efficiency of recycling facilities and the statistical data were integrated to estimate the national actual recycling rate, which turned out to be 87.7% in 2013. Approximately 49.1% of the construction-related waste was recycled as recycled aggregate for concrete production and road base layer for asphalt pavement. Based on the result of MFA, there is 9.8% difference between the actual recycling rate in this study and reported recycling rate by national statistics. In the future, more various C&D waste treatment and disposal facilities, along with aggregate recycling facility, should be investigated to verify the actual recycling rate determined by this study. Statistical accuracy should be further refined through additional field investigations. Our findings can be applicable to development of recycling policies and best management practices for C&D waste streams.

In this study we conducted a material flow analysis (MFA) of the four major types of waste electrical and electronic equipment (WEEE), namely refrigerators, TV sets, washing machines, and air conditioners, based on the most reliable data available from the Eco-Assurance System, other governmental sources, the literature, a field survey, and interviews. A MFA of six major components, iron, copper, aluminum, plastics, precious metals, and rare metals was also conducted. The estimated total generation of WEEE in 2013 amounted to 401.8 thousand tons, of which 3.8% (or, approximately 5% including printed circuit boards) was exported and 55.0% was recycled. The collection by the formal take-back system occupied 34.6% of the total generation, from which 83.9% was recovered as valuables. The six major components amounted to 299.7 thousand tons, among which 89.8% of iron, 91.4% of copper, 56.0% of aluminum, 27.1% of plastics, 37.1% of precious metals, and 6.2% of rare metals were recovered. A high positive correlation was found between the amount of WEEE flowing into the private recycling business and its economic value. Since the recovery ratio in the private sector was estimated to be much lower, while the potential environmental impact was higher, an optimal strategy was identified to enhance the collection by the public sector. Providing economic incentives should be an effective means to encourage private collection through the formal take-back system.