• Nuclear Engineering and Technology
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• 제54권3호
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• pp.826-833
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• 2022

A two-phase natural circulation test using SMART integral test loop (SMART-ITL) was conducted to explore thermo-hydraulic phenomena of two-phase natural circulation in the SMART reactor. Specifically, the test examined the natural circulation in the primary loop under a stepwise coolant inventory loss while keeping the core power constant at 5% of the scaled full power. Based on the test results, three flow regimes were observed: single-phase natural circulation (SPNC), two-phase natural circulation (TPNC), and boiler-condenser natural circulation (BCNC). The flow rate remained steady in the SPNC, slightly increased in the TPNC, and dropped abruptly and maintained in the BCNC. Using a natural circulation flow map, the natural circulation characteristic in the SMART-ITL was compared with those in pressurized water reactor simulators. In the SMART-ITL, a BCNC regime appeared instead of siphon condensation and reflux condensation regimes because of the use of once-through steam generators.

• 상하수도학회지
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• 제29권4호
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• pp.503-510
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• 2015

The objective of this study is to analyze the investment adequacy of the projects implemented according to the master plan on sewerage rehabilitation at Seoul. The planned and actually implemented ratio of invested money on sewage treatment plants (STPs) to sewers were compared in two temporal periods. Though the planned ratio of investment on STPs to sewers was 50:50 (in 2009-2020), the actual implemented ratio in 2009-2013 was 34:66. Until 2020, the greater investment ratio on STPs to sewers should be made considering the necessity of coping with stricter legal compliance on advanced treatment, stormwater treatment and so on. The priority of the planned and partially implemented projects among four STPs and at each STP was evaluated. Considering only the performance indicator of reduced load of BOD, T-N, T-P per the capacity of each STP facility, the performance among four STPs was shown as Jung-Rang>Tan-Cheon>Seo-Nam>Nan-Ji. The reverse order of the performance results in the past may be considered for future investment priority, but the efficiency of operation implemented at each STP, deteriorated status of each STP, investment in the past and so forth should also be considered. As for the priority of projects conducted within each STP, projects related to legal compliance (such as advanced tertiary treatment, stormwater treatment, etc.) have highest priority. Odor-related project and inhabitant-friendly facility related projects (such as building park on STPs, etc.) has lower priority than water quality related projects but interactivity with end-users of sewerage should also be important.

• 상하수도학회지
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• 제25권6호
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• pp.885-892
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• 2011

In this study, LCA(Life Cycle Assessment) on 'Saemangum CSO Project' was carried out to evaluate environmental impact which occurred during the construction and operation periods and the potential environmental impact reduction was analyzed by comparing production and reduction level of pollution loads. LCA was conducted out according to the procedure of ISO14040 which suggested Goal and Scope Definition, Life Cycle Inventory Analysis, Life Cycle Impact Assessment and Interpretation. In the Goal and Scope Definition, the functional unit was 1 m3 of CSO, the system boundary was construction and operation phases, and the operation period was 20 years. For the data collection and inventory analysis, input energies and materials from civil, architecture, mechanical and electric fields are collected from design sheet but the landscape architecture field is excepted. LCIA(Life Cycle Impact Assessment) was performed following the procedure of Eco-Labelling Type III under 6 categories which were resource depletion, eutrophication, global warming, ozone-layer destruction, and photochemical oxide formation. In the result of LCA, 83.4% of environmental impact occurred in the construction phase and 16.6% in the operation phase. Especially 78% of environmental impact occurred in civil works. The Global warming category showed the highest contribution level in the environmental impact categories. For the analysis on potential environmental impact reduction, the reduction and increased of environmental impact which occurred on construction and operation phases were compared. In the case of considering only the operation phase, the result of the comparison showed that 78% of environmental impact is reduced. On the other hand, when considering both the construction and operation phases, 50% of environmental impact is increase. Therefore, this study showed that eco-friendly material and construction method should be used for reduction of environmental impact during life cycle, and it is strongly necessary to develop technology and skills to reduce environmental impact such as renewable energies.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.80-83
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• 2008

As SOC (Social Overhead Capital) has been expanded, the highway road construction has been accelerated and city road system has been more complicated. So, long road tunnels have been increased and traffic flow rate also has been raised. Accordingly, the exhausting gas of vehicle cars seriously deteriorates the tunnel inside air quality and driving view. In order to improve tunnel inside air quality, we may need to introduce a compulsory ventilation system as well as natural ventilation mechanism. The natural ventilation mechanism is enough for short tunnels, meanwhile longer tunnels require a specific compulsory ventilation facility. Many foreign countries already have been devoting on development of effective tunnel ventilation system and especially, some European nations and Japan have already applied their developed tunnel ventilation system for longer road tunnels. More recently, as the quality of life improved, our concerns about safety of driving and better driving environment have been increased. In order to obtain clearer and longer driving view, we are more interested in EP tunnel ventilation system in order to remove floating contaminants and automobile exhaust gas. Evan though it's been a long time since many European countries and Japan applied more economical and environment-friendly tunnel ventilation system with their self-developed Electrostatic Precipitator, we are still dependant on imported system from foreign nations. Therefore, we need to develop our unique technical know-how for optimum design tools through validity investigation and continuous possibility examination, eventually in order to localize the tunnel ventilation system technology. In this project, we will manufacture test-run products to examine the performance of system in order to develop main parts of tunnel ventilation system such as electrostatic precipitator, high voltage power generator, water treatment system, etc.

• 한국항해항만학회지
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• 제28권3호
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• pp.269-276
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• 2004

매립지는 도심부 혹은 내륙지역과는 달리 독특한 지형적 자연환경 특성을 가지고 있으며 내륙지역에 비해 낫은 기온, 강한 바람, 과다한 일사조건, 해염을 포함한 습기라는 기후적 악조건을 가지고 있다. 따라서 워터프런트를 개발할 경우는 매립에 따른 기후환경 특성을 상세하게 파악하여 적합한 개발 및 체계적인 유지관리가 필요하다. 워터프런트의 지형적, 기후적 특성을 충분히 검토하지 않고 개발을 추진한 경우 기후환경의 악화와 더불어 시설의 하자발생 및 부정확한 설비용량 산정에 따른 에너지비용 및 유지관리비용의 상승이 초래될 수 있다. 본 연구에서는 현재 매립ㆍ개발이 진행되고 있는 부산 신항만지역의 환경친화적 에너지 수급계획을 위하여 신항만지역의 표준기상데이터를 작성하고, 이를 바탕으로 현재 계획되어 있는 상업ㆍ업무시설과 주거시설을 대상으로 동적 최대 열부하계산을 실시하여 신항만지역 배후도시의 설비용량 산정을 위한 기초자료를 제시하였다.

• 한국축산시설환경학회지
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• 제10권3호
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• pp.175-182
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• 2004

A study was conducted to develop a management policy of animal waste in Northern Chungbuk province through investigating the status of animal waste management. In management of swine manure, rotary composting including a simple piling method has a portion of $64\%$ using as a liquefied fertilizer $18\%$, purification $9\%$ and ocean dumping $9\%$ respectively. Most of them use the animal waste as a fertilizer to the agricultural land. The exercise ground of dairy farms was bedded with $70\%$ of sawdust and $30\%$ of conventional soil ground besides the stall. They had a storage tank for the waste water from milking parlor. Korean beef cattle farms mostly run sawdust stall, which changed new one in a term of 6$\~$12 months. In case of layer, manure management was conducted in the order of simple piling method, rotary composting and ventilation into the piling mostly. Comparing the amount of excreted animal manure with that of possible spreading, the latter can be spread more than 2.9 times than the former in Northern Chungbuk province. The Northern Chungbuk province is an appropriate place to carry out an environmentally friendly animal production. An utilization model as a liquefied fertilizer should be developed for paddy field, upland field, orchard, and forage field to in-crease the value of animal waste effectively.

• 수산해양교육연구
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• 제29권1호
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• pp.148-157
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• 2017

This study has studied the phenomenon exclusive to the activity of skin scuba among marine sports in Busan region, and such empirical studies are for the development of skin scuba, and even of the entire marine sports, and in order to achieve such objective, the study method centered around qualitative study method of in-depth interview, participatory observation, and documentation study, the results of which are as follows. First is the advantage of the local environment as an open-water location. This study area has beaches of pebbles, and the underwater is also comprised of pebbles up to a certain distance, securing a superior underwater visibility compared to the sand of other Busan regions, and such local environment is thought to be an advantage of skin scuba activity. Second is the satisfaction of accessibility. This study area had an advantage in participant accessibility, which is thought to act as a good strength for the marine sports development of this area in the future. Third is the satisfaction of education. The club instructors of this study area had various marine sports-related licenses such as skin scuba, along with marine lifeguard trainer qualifications to prepare against safety accidents, which are also thought to have positive influences on the education satisfaction for beginners. Fourth is the inconvenient subsidiary facility. This study area has great natural environment for open waters, but the subsidiary facilities of the club for skin scuba activity was found to be very inconvenient by this study, and for the future development of skin scuba, the improvement of subsidiary facilities should be considered. Fifth is the inconvenient parking facilities. The participants in this study area agreed upon the inconvenience of the parking issue alongside the subsidiary facilities. There are always parking issues near the coasts of Busan region, and in order to resolve such issues, active assistance from the City of Busan and each local government, and if such methods are well proposed, the conflict between the marine sports participants and local residents shall be resolved, it would play a great role in the development of marine sports.

• 환경생물
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• 제35권4호
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• pp.654-661
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• 2017

축산폐수에 기인한 오염 물질 저감을 위해 최근 축산폐수처리 후속공정으로 인공습지와 같은 자연친화적인 처리법이 제안되고 있다. 따라서 본 연구는 자연친화적 공법이 수생태독성 저감에도 효과적인지 알아보기 위해 다양한 공정의 인공습지를 제작하여 축산폐수 시료를 대상으로 처리 전후 오염저감율 및 물벼룩 급성 독성 변화를 분석하였다. 본 실험결과, 비록 갈대의 유무 및 종류, 그리고 여재의 종류에 따른 영향은 없으나 인공습지에 처리된 경우 유입수에 비해 TN, TP, COD 농도 저감과 더불어 생태독성 영향이 감소하였다. 따라서 일반 갈대는 물론 바이오갈대와 바이오여재를 사용한 인공습지는 축산폐수의 TN, TP, COD 저감은 물론 생태독성 감소에도 효과적인 공법으로 판단된다. 향후 가축분뇨 정화시설과 연계한 후속처리공정으로 적용하기 위해서는 다양한 성상의 축산폐수를 대상으로 처리효율과 생태독성시험이 연계된 통합평가가 필요한 것으로 사료된다.

• 한국산학기술학회논문지
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• 제18권12호
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• pp.712-721
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• 2017

본 최근 전 세계적으로 홍수의 강도와 빈도가 증가하고 있어 홍수재해가 큰 문제로 대두되고 있다. 이 중 가장 큰 비중을 차지하는 홍수재해는 태풍 및 집중호우와 동반되는 홍수라고 할 수 있다. 이로 인해 하천의 수위가 제방의 둑마루까지 상승하여 월류하는 피해가 발생하고 있으며 이러한 피해는 시설물 자체의 피해뿐만 아니라 제내지의 인명 및 재산피해도 함께 유발시킨다는 점에서 대책 마련이 시급하다. 제방이 월류하였을 때 제방이 붕괴되는 것과 붕괴하지 않고 단순 월류하는 경우의 피해정도는 매우 다르며 제방 자체의 피해는 발생하더라도 붕괴되지 않으면 제내지로 유입되는 유량을 현저히 감소시켜 홍수피해를 감소시킬 수 있다. 따라서 제방의 붕괴가 발달하기 시작하는 뒷비탈의 보호는 중요한 홍수방어방법의 하나다. 본 연구에서는 제방뒷비탈 월류보호공의 형상과 유공율에 따라 수리학적으로 유리한 보호공을 제안하고 각 보호공의 안정성 검토를 위하여 수리실험을 수행하였다. 수리실험을 통해 제방뒷비탈 보호공의 안정성은 보호공의 단위면적당 중량과 높은 상관성이 있음을 규명하고, 보호공이 이탈되는 순간의 유속인 한계유속과 단위면적당 중량과의 관계식을 도출하였다. 본 연구결과를 통하여 국내에서는 아직 도입되지 않은 자연친화적 월류보호공이 현장에 적용됨으로써 홍수시 월류에 의해 발생하는 인명 및 재산피해를 경감시키고, 더 나아가서는 자연친화적인 하천공간이 조성될 수 있을 것으로 기대된다.

• 한국습지학회지
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• 제19권4호
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• pp.533-541
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• 2017

농업, 농촌경관은 다양한 생태계서비스 기능이 있지만 시설원예단지 개발은 환경보전에 대한 고려사항이 없어 단지를 조성 시 필요한 생태계서비스 기능 우선순위 분석을 실시하였다. 시설원예단지의 친환경적 조성을 위한 생태계서비스 기능 및 가중치 산정 방법은 총 3단계에 걸쳐서 진행되었다. 1차 조사결과 17개 기능을 개선방안으로 선정 하였고, 2차 조사에서 5개 기능을 제외 한 12개 기능이 선정되었다. 최종적으로 1. 수질정화 대책, 2. 지하수함양 방안, 3. 지표수저장 공간, 4. 홍수조절 대책, 5. 식생다양성 공간, 6. 탄소배출 저감 방안, 7. 수서곤충 서식 공간, 8. 양서파충류 서식 공간, 9. 경관 및 폐기물 대책, 10. 조류 서식 공간, 11. 열섬완화 방안, 12. 체험/생태교육 방안 순으로 고려할 것을 제안하였다. 기능 향상방법으로 수질정화 대책을 위해 수처리 시설의 구조, 유량, 용량, 유속, 배치, 형태 등 공학적 세밀한 접근과 계획을 제안하고 수질정화 식물인 벼, 부들, 줄, 부레옥잠, 물상추 등의 투입을 고려할 것을 제시했으며, 지하수 함양 대책을 위해 개발면적의 7-10%를 저류지 투입으로 제안하였다. 지표수 저장 공간과 홍수조절 대책을 위해 우리나라 실정에 맞는 저류지 및 저장시설 구조 개발을 제시했으며, 탄소배출 저감과 열섬완화 방안을 위한 녹지공간을 확보를 제안하였다. 생물다양성관 관련된 식생다양성, 수서곤충, 양서파충류 서식을 위한 서식처와 양액배출 관리를 제안하고 경관개선을 위한 녹지확보, 습지조성, 체험교육을 위한 시설투입을 거론하였다. 연구결과는 시설원예단지의 개선방안으로 활용하고 새로운 단지 개발에 있어 정책결정 자료로 활용 할 것을 제안했으며, 이러한 연구를 지속시켜 국가 생물다양성 및 국토환경보전, 지속가능한 농업에 이바지하길 기대하였다.