Technology for high-level-waste disposal employing a multibarrier concept using engineered and natural barrier in stable bedrock at 300–1,000 m depth is being commercialized as a safe, long-term isolation method for high-level waste, including spent nuclear fuel. Managing heat generated from waste is important for improving disposal efficiency; thus, research on efficient heat management is required. In this study, thermal management methods to maximize disposal efficiency in terms of the disposal area required were developed. They efficiently use the land in an environment, such as Korea, where the land area is small and the amount of waste is large. The thermal effects of engineered barriers and natural barriers in a high-level waste disposal repository were analyzed. The research status of thermal management for the main bedrocks of the repository, such as crystalline, clay, salt, and other rocks, were reviewed. Based on a characteristics analysis of various heat management approaches, the spent nuclear fuel cooling time, buffer bentonite thermal conductivity, and disposal container size were chosen as efficient heat management methods applicable in Korea. For each method, thermal analyses of the disposal repository were performed. Based on the results, the disposal efficiency was evaluated preliminarily. Necessary future research is suggested.

Currently, the most widely accepted disposal concept for long-term isolation of high level radioactive waste including spent nuclear fuels is to disposal in a deep geological repository designed and constructed with multiple barriers composed of engineered and natural barriers so that the waste can be completely isolated in a stable deep geological environment. In this concept, an important consideration is the heat generated from the waste due to the large amount of fission products present in the high level waste loaded in the disposal container. For safe and complete isolation of high level radioactive waste in the deep geology, the disposal concepts that meet the thermal requirements for the disposal system design have been developed by harmonizing the thermal characteristics of engineered and natural barriers in Korea. In this paper, the deposition hole configuration and the decay heat dissipation area (surface area) of disposal container were considered for the efficient thermal management in the deep geological disposal concept. Heat transfer through the waste form, its container and surrounding components and the rock will be mainly by conduction. Heat transfer by radiation and convection can be negligible after backfilling. When considering heat conduction, according to Fourier’s law, if the thermal conductivity of the repository components is the same, the greater the heat dissipation area and the adjacent temperature gradient, the greater the conduction effect. Therefore, rather than the conventional concept of loading 4 PWR spent fuel assemblies per disposal container and placing one disposal container in a deposition hole, it is better to load one assembly per disposal container and place 4 disposal containers in a deposition hole. In this case, it was found that the disposal area could be reduced through efficient thermal management. Considering this thermal management method as an alternative to the concept of deep geological disposal, additional research is needed.

본 연구는 부산광역시를 대상으로 열환경을 개선하기 위한 바람길 관리 방안 제안을 목적으로 한다. 이를 위해, Landsat-7 위성 열영상 자료와 공간통계 분석을 실시하여 부산광역시의 Hot spot과 Cool spot 지역 특성을 파악하였으며, WRF 기상모의를 통해 주요 바람길을 분석하였다. 그 결과, Hot spot 지역 중 열환경 개선이 요구되는 지역은 부산진구, 동래구, 연제구와 사상구 공업지역, 대규모 시설지역에는 부산항 부두로 나타났으며 주요 바람길에는 금정산~백양산~ 구덕산 계곡부로서 확인되었다. 이를 바탕으로 바람길 관리 전략을 제시하면 다음과 같다. 공업시설과 부산항 일대는 대기 온도 상승 요인으로서 주변 지역의 열환경을 악화시키므로 시설의 온도저감 및 바람길을 고려한 도시·건축계획이 요구된다. 바람길 관리가 필요한 지역으로 만덕동, 사직동 일대 산림에 대한 추가적인 훼손이 일어나지 않도록 하여야 하며, 산림과 인접한 지역의 대규모 고층아파트는 산림에서 생성된 차고 신선한 공기의 흐름을 방해하므로 금정산과 접해있는 제3종 일반주거지역의 신규·재개발에 따른 고층아파트 단지 조성은 지양해야 한다. 본 연구 결과는 부산광역시의 기후변화에 대응한 도시계획 및 환경계획수립 시 기초자료로 활용할 수 있을 것으로 기대한다.

본 연구에서는 단면설계 및 열 교환 장치 위치 변경을 통해 온실의 구조 변경을 진행하였으며, 선행연구를 통해 개발된 모델을 근간으로 하여 개선 여부에 따른 온실 내부 환경을 예측하였다. 단면형상과 열 교환 장치의 개선 후 유속 변화에 따른 시뮬레이션 분석을 진행하였으며, 이 때 온도와 균일도는 각각 평균 0.65°C, 0.75%p 상승함을 확인하였다. 해석대상 온실과 같은 소규모 온실의 경우 방열관의 난방성능 개선보다 FCU에 의해 형성되는 공기 유동이 균일한 환경 조성에 더 큰 영향을 미치는 것으로 판단된다. 개선 전 ‧ 후 온실에 환기시스템 적용 시 공기 유동 특성 분석을 위해 시뮬레이션 분석을 진행하였다. 공기 유동과 공기령은 유사한 분포를 보였으며, 개선 후 온실의 공기령이 개선 전 온실 대비 18초 낮게 나타났다. 개선 전 ‧ 후 온실 시뮬레이션 분석 결과 전체적으로 개선된 온실에서의 평균온도 및 온도 균일도 상승, 최대편차 감소 등 내부 환경의 균일성이 향상됨을 확인하였다. 선행연구로 개발 된 모델은 형상 변경, 열 교환 장치 위치 변경 등에 따라 변화하는 온실 내부 환경을 예측할 수 있음을 확인하였으며, 온실 설계, 온실 내 난방시스템 설계 등의 분야에 적용 가능할 것으로 판단된다.

There has been a steady rate of accident in Coal Thermal Power Plants which have relatively higher chance of mortality. However, neither the systematic view of safety management nor the methodology such as safety factors or system requirements are yet to be studied in detail. Therefore, this study aims to propose a methodology to preemptively deal with safety issues and to secure fact focused responsibility in safety. It consists of two main parts. First, the Safety Measurement Index(SMI) with total 50 factors is proposed by analyzing the key factors that contribute to safety accidents based on failure mode and effect analysis (FMEA) and quality function deployment (QFD). To analyze the safety requirements, index presented by major countries and organizations are discussed. Second, main features of intelligent CCTV are studied to determine their relative importance for the framework of Smart Safety Management System (SSMS). Main features are discussed with four technological steps. Also, QFD was held to analyze to analyze how key technologies deal with Quality Measurement Index(QMI). The research results of this study reveal that scientific approaches could be utilized in integrating CCTV technologies into a smart safety management system in the era of Industry 4.0. Moreover, this reasearch provides an specific approach or methodology for dealing with safety management in Coal Thermal Power Plant.

Electronic packaging involves interconnecting, powering, protecting, and cooling of semiconductor circuits fur the use in a variety of microelectronic applications. For microelectronic circuits, the main type of failure is thermal fatigue, owing to the different thermal expansion coefficients of semiconductor chips and packaging materials. Therefore, the search for matched coefficients of thermal expansion (CTE) of packaging materials in combination with a high thermal conductivity is the main task for developments of heat sink materials electronics, and good mechanical properties are also required. The aim of this work is to develop copper matrix composites reinforced with carbon nanofibers. The advantages of carbon nanofibers, especially the good thermal conductivity, are utlized to obtain a composite material having a thermal conductivity higher than 400 W/mK. The main challenge is to obtain a homogeneous dispersion of carbon nanofibers in copper. In this paper, a technology for obtaining a homogeneous mixture of copper and nanofibers will be presented and the microstructure and properties of consolidated samples will be discussed. In order to improve the bonding strength between copper and nanofibers, different alloying elements were added. The microstructure and the properties will be presented and the influence of interface modification will be discussed.

For microelectronic circuits, the main type of failure is thermal fatigue. Therefore, the search for matched coefficients of thermal expansion (CTE) of packaging materials in combination with a high thermal conductivity is the main task for developments of heat sink materials electronics, and good mechanical properties are also required. The aim of this work is to develop copper matrix composites reinforced with carbon nanofibers to meet these requirements. In this paper, a technology for obtaining a homogeneous mixture of copper and nanofibers will be presented and the microstructure and properties of consolidated samples will be discussed.

  This study suggests plan of green space management based on the result of research apprehending the characteristic through sorting types of city thermal environment targeting summer which thermal pollution is the most serious. Considering anthropogenic heat, development level of wind road, thermal environment, as a result of types of thermal environment process, it is appeared 36 types, and 10 types is relevant of this research subject. Type Ⅰ-1, size of building is large, artificial covering area is wide, and thermal load of anthropogenic heat is high, typeⅡ-1, development condition of wind road is incomplete as Ⅱlevel, entering cold air is difficult and thermal management and improvement is needed area. Type Ⅲ-1, scale is large and it is area of origin of cold air, development level of wind road is mostly favorable, type Ⅲ-2 is revealed as smaller scale than Ⅲ-1, and small area of origin of cold air. Type Ⅳ, anthropogenic heat is 81～150 W/㎡, average, but development function of wind road is very favorable. Type Ⅴ, large area of thermal load and the origin of cold air are distributed as similar ratio, and level of development function of wind road is revealed as Ⅱ level. According to standard of type classification of thermal environment, as a result of suggesting plan of green space management and biotops area ratio, type Ⅰ-1 is buffer green space and waterway creation, goal biotops area ratio 35%, type Ⅱ-1 afforestation in site and goal biotops area ratio 40%, type Ⅲ-1, preservation plan to display the current function continuously is requested. Type Ⅳ suggests afforestation of stream current, and typeⅤ suggests quantitative increase of green space and goal biotops area ratio 45%.