Radioactive waste generated in large quantities from NPP decommissioning has various physicochemical and radiological characteristics, and therefore treatment technologies suitable for those characteristics should be developed. Radioactively contaminated concrete waste is one of major decommissioning wastes. The disposal cost of radioactive concrete waste is considerable portion for the total budget of NPP decommissioning. In this study, we developed an integrated technology with thermomechanical and chemical methods for volume reduction of concrete waste and stabilization of secondary waste. The unit devices for the treatment process were also studied at bench-scale tests. The volume of radioactive concrete waste was effectively reduced by separating clean aggregate from the concrete. The separated aggregate satisfied the clearance criteria in the test using radionuclides. The treatment of secondary waste from the chemical separation step was optimally designed, and the stabilization method was found for the waste form to meet the final disposal criteria in the repository site. The final volume reduction rates of 56.4~75.4% were possible according to the application scenario of our processes under simulated conditions. The commercial-scale system designs for the thermomechanical and chemical processes were completed. Also, it was found that the disposal cost for the contaminated concrete waste at domestic NPP could be reduced by more than 20 billion won per each unit. Therefore, it is expected that the application of this technology will improve the utilization of the radioactive waste disposal space and significantly reduce the waste disposal cost.

PURPOSES : High concentrations of particulate matter (PM) are emitted or generated from vehicle emissions in urban roads with dense transient populations. To reduce the effect of PM emission on bus stop users at roadsides, a plan to reduce PM emitted from the roadside must be devised. In this study, an atmospheric environment at a roadside is simulated in a large-scale environment chamber, and a test for reducing PM around the bus stop is conducted by installing a bus stop adapted to a PM reduction system. METHODS : Exhaust gas is injected into the experimental and reference chambers using diesel and gasoline vehicles for roadside airquality simulations. The two vehicles are operated in an idle state without an acceleration operation to emit exhaust gas uniformly, and the initial conditions are achieved by injecting car emissions for approximately 40 min. The initial condition is set to 1 ppm of NOx concentration in the environment chamber. Between the two environment chambers, a bus stop adapted to the PM reduction system is installed in the experimental chamber to conduct a PM reduction experiment pertaining to the air quality around the roadside. The experimental progress is set as the start time of the experiment based on the time at which the initial conditions are achieved; simultaneously, the PM reduction system in the experimental chamber is operated. After the simulation is commenced, the PM concentration, which changes over time, is measured using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) without additional injection of car emissions or pollutants. The HR-ToF-AMS measures the chemical composition of non-refractory PM1.0 (NR-PM1.0) in real time. RESULTS : The NR-PM1.0 compound (organic aerosol (OA), NO3 -, SO4 2-) increases by 160% compared with the simulated initial concentration up to T90min in both environmental chambers; this is speculated to be due to secondary formation. The reference chamber indicates a slight decrease or a steady-state after T90min, whereas the experimental chamber indicates a gradually decrease as the experiment progresses. The bus stop adapted to the PM reduction system reduces the amount of black carbon in the experimental chamber by 37% at 200 min. This implies that the PM emitted from the roadside is filtered via the PM reduction system installed at the bus stop, and cleaner air quality can be provided to passengers. CONCLUSIONS : The PM reduction system evaluated in this study can be detached from and attached to the outdoor billboard of a bus stop. Since it adopts air filtration technology that uses a high-efficiency particulate air filter, it can be maintained and managed easily. In addition, it can provide an atmospheric environment with reduced PM emission to passengers as well as provide a better air-quality condition to passengers waiting for public transportation near roadsides.

본 연구는 식품 생산 환경에서 A. ochraceus를 저감하기 위하여 물리적 제어기술인 광살균(LED, UV), 열수 처리를 통하여 그 효과를 확인하고자 하였다. 이를 위하여 A. ochraceus 포자 현탁액(107-8 spore/mL)를 스테인리스 칩에 1 mL 접종하고 37oC에 건조한 후 각각의 물리적 처리에 적용하였다. LED를 활용하여 30분, 1, 2, 5, 8, 11시간 처리하였으나 균수에서 유의적인 차이를 확인하지 못하였으나 UV-C와 열수침지에서는 모두 A. ochraceus가 유의적으로 감소하였다. UV-C를 단독으로 스테인리스 칩에 360 kJ/m2까지 조사한 결과 A. ochraceus가 1.27 log CFU/ cm2 까지 유의적으로 감소한 것을 확인하였다. 열수 처리에서는 가장 고온인 83oC에서 5분간 침지할 경우 A. ochraceus 초기 접종농도인 6.49 log CFU/cm2를 모두 사멸 시켰다. 그러나 고온의 열에너지를 5분간 현장에서 유지하는 것이 쉽지 않으므로 경제성과 사용 적합성 등을 고려하여 비교적 저온인 60oC와 자외선을 복합처리 하여 적절한 저감 조건을 확인하고자 하였다. 복합처리 결과 미온수에서도 침지시간 증가와 UV-C 조사량 증가에 따라 유의적으로 감소하여 불검출되었다. 이러한 결과들을 바탕으로 미온수인 60oC 물에 작업도구 등을 침지하여 3분 간 침지한 후 10분 이상 UV 살균처리 장치에 비치하여 둔다면 작업 중 A. ochraceus가 식품으로 교차오염되는 가능성을 줄일 수 있을 것으로 예상된다.

The global trend is the application of heat-treated omission materials to reduce the manufacturing cost of automobile steering parts. Attempts have been made to apply heat-treated omission materials in domestic, but they are delayed due to concerns over rising cold forging process costs. For quantitative prediction of cold forging process cost, fatigue properties of forging die materials were evaluated. Based on this, the die life and cost were predicted quantitatively, and the manufacturing cost reduction of automobile steering parts using heat-treated material was found to be about 11%. Also, various methods to improve die life were additionally presented.

PURPOSES : Over the years, the concentration of fine dust is gradually increasing, thereby aggravating the seriousness of the situation. Accordingly, this study intends to install a clean road system using low impact development (LID) techniques on the roadside in order to reduce the scattering of dust on roads effectively. This system stores rainwater collected through gutters in rainy weather and sprays water onto the pavement surface to reduce the scattering of road dust. METHODS : The developed clean road system consists of a water tank, controller, rain detection sensor, and solar cell. Based on this, a test-bed construction was used to evaluate its applicability. By applying the developed system, actual applicability was evaluated through total suspended solid (TSS) test and fine dust measurement. TSS test was conducted to measure the reduction rate of scattering dust on the road owing to the water injected by the clean road system. A spray nozzle was used for the TSS test, and a nebulization nozzle was used for the measurement of fine dust. In order to increase the reliability of the test, three measurements were taken each, for normal road as well as unfavorable conditions road that reproduced the construction site. RESULTS : In this study, fine dust concentration measurement and TSS test were conducted to evaluate the practical applicability of the developed clean road system. From the TSS test, it was found that for both general roads and roads depicting bad conditions, the TSS value after the first spray was the highest, and the value after the second spray was sharply reduced, such that most of the re-dispersed dust was washed out after the first spray, and similar TSS value results were obtained after the third spray. Based on this result, the result of fine dust measurement showed similar fine dust reduction effect of 9%-15.9% regardless of the concentration of fine dust in the atmosphere. These results indicate that the concentration of fine dust in the atmosphere does not significantly affect of the degree of reduction in fine dust. CONCLUSIONS : In this study, a clean road system for reducing fine dust on the road was developed and its applicability was evaluated. In a future study, we intend to check the performance of the drainage pavement through performance evaluation of water permeability coefficient test and performance test in the form of drainage pavement. Through this, we intend to evaluate the applicability of the clean road system to which drainage pavement is applied. Moreover, we will develop a clean road system that applies drainage packaging, and analyzes the degree of fine dust reduction according to the spray angle, spray amount, and spray time of the clean road system in order to study the spray system with the optimum amount of fine dust reduction. In addition, in order to reduce fine dust in the winter, when fine dust is mainly generated, it is planned to install heating wires in spray pipes where freezing is expected. Lastly, the black ice prevention effect will be analyzed by mixing a certain amount of sodium chloride when spraying water.

최근 국내에서 세계 최초로 개발한 SWRO-PRO 복합해수담수화 시스템은 압력지연삼투(PRO) 기술을 활용하여 역삼투(SWRO) 해수담수화 플랜트에서 발생하는 고염도 농축수의 삼투에너지를 회수하는 기술이다. 고염도 농축수와 저염도 하수처리수를 각각 PRO 시스템의 유도용액과 유입수로 사용하며, 두 용액의 농도차에 의해 발생되는 삼투에너지를 압력교환장치(isobaric pressure exchanger)를 통해 회수하여 SWRO 고압펌프에서 필요한 에너지를 줄이거나, 터빈 형태의 에너지 회수장치(Pelton turbine)를 통해 전력을 생산하는 기술이다. PRO 시스템을 통해 회수된 에너지는 해수담수화 운영비를 절감하는데 기여하고, 고농도 농축수의 희석 방류로 해양생태계 영향을 최소화 시킬 수 있다.

현재의 역삼투막 담수화는 전체 담수화 시장의 60%정도를 점유하고 있으며, 향후 2020년에는 70%까지 증가할 것으로 예상되고 있다. 역삼투막 공정의 Cost는 전처리 공정, 멤브레인 배치, 원수 및 최종 생산수의 요구수질 조건 등에 따라 다르므로, 설계에서 운영에 소요되는 모든 비용 구성을 이해하는 것이 중요하다. 대부분 전력비와 시설투자 비용에 80% 이상이며, 운영/유지보수에 20% 정도 차지한다. 당사에서는 역삼투막 전력비저감 및 고효율 전처리 개발과 운영/유지비용을 줄이기 위한 기술개발을 하고 있다. 또한 탈황 폐수처리를 위한 증발 무방류(Zero Liquid Discharge) 공정에 역삼투막(RO) 또는 정삼투막(FO) 공정을 결합하여 증발기의 용량을 줄여 열/전기에너지를 저감하는 공정 연구와 저염분 처리를 위한 전기화학 탈염 공정(CDI) 연구 개발을 수행하고 있다.

Excessive nitrate content in drinking groundwater is one of the sources of nitrate-nitrogen that threatens humanhealth all over the world. Nitrate-nitrogen reduction technology is categorized into membrane filtration, electro-dial-ysis, ion exchange, adsorption, chemical methods, and biological methods according to the principle of eliminationfrom water. In particular, an adsorption technique is the most popular and common process because of its cost effec-tiveness, convenience, and effective adsorption. In this review, the application of conventional adsorbents used toreduce nitrate-nitrogen from drinking water is discussed and novel technologies on nitrate-nitrogen removal are intro-duced. Furthermore, the recent development of novel nitrate-nitrogen adsorbents from biopolymers such as chitosanand agricultural and industrial byproducts is reviewed.

경막결정화를 이용한 산화물 사용후연료의 전해환원 공정에서 발생하는 LiCl 염폐기물 내 포함되어 있는 Cs 및 Sr을 분리(농축)에 대한 실험을 수행하였다. 결정화 공정에서 Cs 및 Sr과 같은 불순물들은 불순물들의 용융염 상 및 결정상에 대한 용해도이 차리로 분리되어 최종적으로 작은 양의 LiCl 용융염내에 농축된다. 본 연구에서는 LiCl-CsCl-SrCl2 계에대한 고체-액체 상평형도를 통해 결정화를 통한 분리가능성을 파악하였으며 열전달방정식 의 계산을 통해 경막결정화 운전중 LiCl 용융염상의 온도분포를 예측할 수 있었다. 경막결정화 공정에서 결정성 장 속도는 분리효율에 큰 영향을 미쳤으며 90%의 LiCl 재생율을 가정할 경우 20-25 l/min의 냉각속도 그리고 0.2 g/min·cm2보다 작은 결정성장 속도조건에서 각각의 Cs 및 Sr에 대하여 90% 정도의 분리효율을 나타내었다.

전 세계적으로 이상 고온, 폭우, 가뭄, 지진, 해일 등이 빈번하게 발생하고 있다. 그 피해 규모도 앞으로 계속 커질 전망이다. 경제활동의 주체인 기업이 이러한 자연 재해로 인하여 지속적이고 안정적으로 운영되지 못하게 된다면 이는 기업자체는 물론 치 열한 글로벌 경쟁체제 속에서 국가경쟁력향상에 상당한 타격을 줄 수 있다. 하지만 우리나라의 기업은 선진국에 비해 상대적으로 자연재해 발생 시 체계적인 방재시스템을 구축하지 못하고 있다. 본 논문에서는 자연재해저감기술 개발의 필요성과 선진국가의 사례들을 통한 우리나라의 자연재해저감기술이 나아갈 방향성을 모색하고자 한다.

최근 정부의 미세먼지 특별법이 발효됨에 따라 비상저감조치 시행시 건설현장 및 공장 작업시간을 조정 및 단축하도록 권고하고 있지만 정량적인 기준 및 저감기술 부재로 인해 기업의 자발적 참여를 유도하는 수밖에 없는 실정이다. 또한 최근 도로포장 재료생산 플랜트에서 발생하는 비산먼지 및 유해가스로 인한 피해사례가 다수 발생하고 있으며 이로 인한 공장 주변 주민들과의 갈등이 심각한 실정이다. 이에 본 연구에서는 국내외 도로포장 관련 비산먼지 발생현황 및 관련법에 대한 조사를 수행하고, 도로포장 전주기(생산-시공-운영)에서의 단계별 발생량 조사를 통해 각 단계에 적합한 비산먼지 저감기술 개발 및 적용방안을 제시하고자 한다.