• 한국항행학회논문지
• /
• 제18권6호
• /
• pp.562-568
• /
• 2014

본 연구는 항공기 지상이동 유도 및 통제시스템(A-SMGCS)의 안전성 평가 기준과 과거에 수행된 연구개발 프로젝트의 사례연구에 대한 것이다. A-SMGCS 시스템은 저시정 상태 등과 같이 기존 공항의 효율성을 저해시키는 환경에서도 이전과 동일한 효율성을 유지한 상태에서 안전하게 운영하기 위하여 항공기 및 지상이동체의 통제를 기반으로 경로, 안내 및 감시를 제곤하는 시스템이다. 최근 한국과 유럽 등에서는 공항 이동 구역의 안전한 통제를 위하여 A-SMGCS 시스템 개발을 진행하고 있다. 항공 산업과 같이 안전을 근간으로 하는 산업 분야에서는 운용시스템에 대한 안전성 입증과 보장이 반드시 필요하다. 본 연구는 이러한 안전성을 요구하는 A-SMGCS의 안전 목표 수준을 검증하기 위한 안전성 평가 기준과 기존 연구 사례를 분석하였다.

• 한국산업보건학회지
• /
• 제22권3호
• /
• pp.235-243
• /
• 2012

Objectives: The purpose of this study is the work environment management method through risk assessment and investigation of the work place that deals with Ammonium nitrate, based on information in and outside the country. Methods: This study suggests method of work environment management through risk assessment and investigation of the work place that deals with Ammonium nitrate, and finds out cases of Ammonium nitrate causing hazard, danger and health risk, based on literature investigation. Results: Rats exposed repeatedly to $LD_{50}$ 2,217 mg/kg(rat), $LC_{50}$ 88.8 mg/L(rat, skin) which cause high level of skin irritation, reported 1 $mg/m^3$ of NOAEL, while LOAEL was less than 100 mg/kg for the rats orally administered with the $LD_{50}$ 2,217 mg/kg(rat), $LC_{50}$ 88.8 mg/L(rat, skin), for 13 weeks. Domestically 31,640 ton/y of ammonium nitrate has been used in 22 workplace and the result of workplace assessment was 0.0171-0.9983 $mg/m^3$. ADD was 8.77-59.63 ${\mu}g/kg-day$ according to the exposure scenario. In other words the result of the risk assessment goes beyond the 'standard 1'. Conclusions: Ammonium nitrate creates a high level of irritation and toxicity when coming in breathe it or contact with skin, and is classified as category3 of GHS and specific target organ toxicant (irritating respiratory system). Exposure level at work places needs to be maintained under $1mg/m^3$, to prevent workers from being damaged.

• 대한원격탐사학회지
• /
• 제39권6_2호
• /
• pp.1529-1539
• /
• 2023

바다의 색을 관측하여 해양환경을 관측하는 천리안 해양위성 2호(Geostationary Ocean Color Imager-II, GOCI-II)의 자료는 지상국 시스템에서 다양한 보정과정을 거쳐 Raw~Level 2 (L2)로 생산되는데, 각 처리 단계에서 발생하는 품질 정확도는 단계별로 누적되어 위성자료의 오차가 점차 증폭된다. 이에 GOCI-II의 Level-1A/B (L1A/B) 자료에서 발생할 수 있는 광학적 품질 및 위치보정 성능 오차를 측정할 수 있도록 GOCI-II 지상국 시스템을 개선하였다. 신규로 구축된 광학적 품질 및 위치보정 성능 평가 모듈(Radiometric and Geometric Performance Assessment Module, RGPAM)은 시험 운영을 통해 성능 측정, 측정 결과의 표출 및 저장 등 기능들이 정상 운영됨을 확인하였다. RGPAM을 통해 측정된 성능들은 향후 GOCI-II 검출기의 감도 저하에 따른 실시간 복사보정 모델 개선, 위성 L1A/B 자료의 품질 일관성 확인 및 이슈사항에 대한 재보정 방안 마련을 위한 기초자료로 활용될 수 있을 것으로 기대한다.

• Nuclear Engineering and Technology
• /
• 제52권9호
• /
• pp.2085-2091
• /
• 2020

The license for Kori-1, the first commercial reactor in Busan, Korea, was terminated in June 2017; therefore, preparations are being made for its decommissioning. Because the radioactivity of Bio-shield varies greatly throughout the structure, the doses received by the workers depend on the location, order, and duration of dismantling operations. Thus, a model for evaluating the worker external dose during the dismantling of the Kori-1 bio-shield was developed, and work scenarios for dose assessment were designed. The Dose evaluation code VISIPLAN was used for dose assessment. The dose rate around the bio-shield was evaluated and the level of exposure to the operator was evaluated according to the work scenario. The maximum annual external dose was calculated as 746.86 mSv for a diamond wire saw operator under dry cutting conditions, indicating that appropriate protective measures, such as changing dismantling sequence, remote monitoring, shield installation, and adjustment of work team are necessary for the safe dismantling of the bio-shield. Through these protective measures, it was found that the worker's dose could be below the dose limit.

• 방사선산업학회지
• /
• 제17권1호
• /
• pp.33-44
• /
• 2023

The deep geological repository of high-level radioactive waste shall be designed to meet the safety objective set in the form of radiation dose or corresponding risk to protect human and the environment from radiation exposure. Engineering feasibility and conformity with the safety objective of the facility conceptual design can be demonstrated by comparing the assessment result using the computational model for scenario(s) describing the radionuclide release and transport from repository to biosphere system. In this study, as the preliminary study for developing the high-level radioactive waste disposal facility in Korea, we reviewed and analyzed the entire list of FEPs and how to handle each FEP from a general point of view, which are selected for the geosphere region in the radiological safety assessment performed for the license application of the KBS-3 type deep geological repository in Finland and Sweden. In Finland, five FEPs (i.e., stress redistribution, creep, stress redistribution, erosion and sedimentation in fractures, methane hydrate formation, and salt exclusion) were excluded or ignored in the radionuclide release and transport assessment. And, in Sweden, six FEPs (i.e., creep, surface weathering and erosion, erosion/sedimentation in fractures, methane hydrate formation, radiation effects (rock and grout), and earth current) were not considered for all time frames and earthquake out of a total of 25 FEPs for the geosphere. Based on these results, an FEP list (draft) for the geosphere was derived, and the relative importance of each item was evaluated for conducting the radiological safety assessment of the domestic deep geological disposal facility. Since most of information on the disposal facility in Korea has not been determined as of now, it is judged that all FEP items presented in Table 3 should be considered for the radiological safety assessment, and the relative importance derived from this study can be used in determining whether to apply each item in the future.

• Geomechanics and Engineering
• /
• 제38권5호
• /
• pp.529-539
• /
• 2024

A high-level nuclear waste (HLW) repository is designed for the long-term disposal of high-level waste. Positioned at depths of 500-1000 meters, it offers an alternative to the insufficient storage space for spent fuels, providing a long-term solution. High-level waste emits heat and radiation, causing structural deterioration, including strength reduction and cracks. Therefore, the use of piezoelectric sensors for structural health monitoring is essential for evaluating the safety of the structure over time. Unlike other structures, the HLW repository restricts human access after the disposal of HLW, rendering sensor replacement impossible. Therefore, it is necessary to assess both the lifespan and suitability of sensors under the disposal conditions in the HLW repository. This study employed an accelerated life test (ALT) to assess the sensor's lifespan under disposal conditions. Failure modes, failure mechanisms, and operational limits were analyzed through accelerated stress test (AST). Additionally, the parameters of the Weibull life probability distribution and the Arrhenius accelerated life model were estimated through statistical methods, including the likelihood ratio test, maximum likelihood estimation, and hypothesis testing. Results confirmed that the sensor's lifespan decreases significantly with the increase in the temperature limit of the HLW repository. The findings of this study can be used for improving sensor lifespan through shielding, development of alternative sensors, or lifespan evaluation of alternative monitoring sensors.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2005년도 춘계학술대회 논문집
• /
• pp.175-180
• /
• 2005

As the high performance computer system increases, improving of reality and usefulness causes the virtual environment of simulator to be used widely as training and assessment tool. Although some domestic companies have developed train driving simulators since about mid of 1990s, accumulation of technology and experience is not yet sufficient compared to foreign makers. This paper describes system composition, training and assessment regimes for high level train driving simulator. When the subsystems are designed, comprehension of train system is emphasized and the functions that simulator should provide are discussed.

• Nuclear Engineering and Technology
• /
• 제52권10호
• /
• pp.2221-2229
• /
• 2020

After the Fukushima Daiichi nuclear power plant (NPP) accident, level 3 probabilistic safety assessment (PSA) has emerged as an important task in order to assess the risk level of the multi-unit NPPs in a single nuclear site. Accurate calculation of the radionuclide concentrations and exposure doses to the public is required if a nuclear site has multi-unit NPPs and large number of people live near NPPs. So, there has been a great need to develop a new method or procedure for the fast and accurate offsite consequence calculation for the multi-unit NPP accident analysis. Since the multi-unit level 3 PSA is being currently performed assuming that all the NPPs are located at the same position such as a center of mass (COM) or base NPP position, radionuclide concentrations or exposure doses near NPPs can be drastically distorted depending on the locations, multi-unit NPP alignment, and the wind direction. In order to overcome this disadvantage of the COM method, the idea of a new multiple location (ML) method was proposed and implemented into a new tool MURCC (multi-unit radiological consequence calculator). Furthermore, the MURCC code was further improved for the multi-unit level 3 PSA that has the arbitrary number of multi-unit NPPs. The objectives of this study are to (1) qualitatively and quantitatively compare COM and ML methods, and (2) demonstrate the strength and efficiency of the ML method. The strength of the ML method was demonstrated by the applications to the multi-unit long-term station blackout (LTSBO) accidents at the four-unit Vogtle NPPs. Thus, it is strongly recommended that this ML method be employed for the offsite consequence analysis of the multi-unit NPP accidents.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2021년도 학술발표회
• /
• pp.455-455
• /
• 2021

The Life Cycle Assessment (LCA) as an environmental impact assessment tool has received increasing attention over the years. Unlike the water footprint (WF) and carbon footprint (CF) assessments whose focus is only on a single environmental aspect, the LCA systematically analyzes the different impacts along the entire life cycle, making possible the identification of potential environmental tradeoffs. In Korea, LCA has drawn much attention from both industry and academia since the mid-90s. However, the level of Korea-related LCA studies with respect to different sectors in the past 20 years has not been analyzed. This study, therefore, sought to assess the status of environmental Life Cycle Assessment (LCA) studies in Korea, with a view to understanding the current level of sustainability reporting and identify potential research gaps. Online searches of English written articles published between 2000 and 2019 were conducted on Google, Google scholar, Scopus, and Web of Science databases using the Keywords "life cycle assessment", "lca", and "Korea." At the end of the search, about 88 LCA related studies were identified for Korea within the study period. Majority of these studies focused on the construction (49%) and energy (31%) sectors with fewer environmental studies on the transportation (9%), manufacturing (8%), agriculture (2%), and information and communication (1%) industries. Based on publication trend, results show that LCA studies in Korea have been on the rise in the past 20 years, even though the number of publications has not followed a constant pace. In comparison with the economic sectors of the country, reports show an inadequacy in the coverage of major industries of growing economic relevance like the tourism, health, and agriculture, suggesting a need to further increase and improve LCA related studies in these sectors.

• Nuclear Engineering and Technology
• /
• 제50권8호
• /
• pp.1246-1254
• /
• 2018

The importance of performing Level 3 probabilistic safety assessments (PSA) along with a general interest in assessing multi-unit risk has been sharply increasing after the Fukushima Daiichi nuclear power plant (NPP) accident. However, relatively few studies on multi-unit Level 3 PSA have been performed to date, reflecting limited scenarios of multi-unit accidents with higher priority. The major difficulty to carry out a multi-unit Level 3 PSA lies in the exponentially increasing number of multi-unit accident combinations, as different source terms can be released from each NPP unit; indeed, building consequence models for the astronomical number of accident scenarios is simply impractical. In this study, a new approach has been developed that employs the look-up table method to cover every multi-unit accident scenario. Consequence results for each scenario can be found on the table, established with a practical amount of effort, and can be matched to the frequency of the scenario. Preliminary application to a six-unit NPP site was carried out, where it was found that the difference between full-coverage and cut-off cases could be considerably high and therefore influence the total risk. Additional studies should be performed to fine tune the details and overcome the limitations of the approach.