• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4083-4095
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• 2023

Currently, various research institutes in Korea are conducting research to develop a safety case for deep geological repository for high-level radioactive waste (HLW). In the past, low and intermediate-level waste (LILW) was approved by a regulatory body by performing a post-closure safety assessment, but HLW has different disposal characteristics and safety objectives are different. Therefore, in the case of HLW, safety assessment should be performed based on these changed conditions, and specific procedures are also under development. In this paper, the regulatory status of prior research institutes, feature, event and process (FEP) and scenario development cases were investigated for well-organized FEP and scenario development methodologies. In addition, through the results of these surveys, the requirements and procedures necessary for the FEP and scenario development stage during the safety assessment of repository for HLW were presented. These review results are expected to be used to identify the overall status of previous studies in conducting post-closure risk assessment for HLW repository, starting with identifying regulatory requirements, the most basic element.

• 터널과지하공간
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• 제11권2호
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• pp.132-145
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• 2001

핵변환 후 영구 처분될 가압경수로 및 중수로용 사용후 핵연료에 대한 인간 생태계에 대한 영향을, 직접 처분하는 경우와 비교해 보았다. 심지층 처분된 용기에 저장된 사용후 핵연료로부터 유출된 방사성 핵종들이 공학적 방벽을거쳐 결정질 기반암 내 균열대를 통해 지하수의 흐름을 따라 이동하면서, 다양한 지질 및 암종을 거쳐 생태 환경으로 도달한다는 핵종 유출 시나리오 중 가장 보수적인 시나리오인 우물 시나리오에 대한 위해도를 평가하여 상대인 환경친화성을 정량적으로 제시하였다. 현재 국내에 가속기와 미임계형 원자로를 함께 사용하는 핵변환 시스템과 임계형 원자로와 같은 핵변환시스템이 개념적인 수준에서 개발되고 있어, 이 연구를 통해 향후 핵변환시스템 연구에서 요구되는 항목들도 기술적 개선, 경제성 제고, 환경 친화성, 그리고 수용성 측면에서 제시해 보았다.

• 환경영향평가
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• 제20권2호
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• pp.227-234
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• 2011

In the study, CE-QUAL-W2 was used and its examination and correction were conducted targeting 2001 and 2003 when the condition of rainfall was contradicted. Using the proved model in 2003, a scenario was implemented with management of locations for dewatering outlets and actual data for dam management in 1987 when inflow and outflow level were almost same. In case of the scenario which the location of dewatering outlets was 5m higher than usual location, exclusion efficiency for turbid water inflow at the beginning of precipitation was good. In case of the scenario which the location of dewatering outlets was 10m lower than usual location, exclusion efficiency for excluding turbid water remained in a reservoir after the end of precipitation. However, the scenario applying dam management data in 1987, exclusion efficiency was relatively low. In the scenario, power-generating water release spot at EL.57m for first four days after the beginning of precipitation, EL.52m for 5th to 8th and EL.42m from 9th days. An analysis of the scenario reveals that both excessive days exceeded 30 NTU and average turbidity levels were decreased comparing before and after the alteration on outlets. The average turbidity levels were decreased by minimum of 55% to maximum of 70% and 30NTU exceeding days were decreased by 45 days at maximum. Also, since it could exclude most of turbid water in a reservoir before the destatifcation, the risk for turbid water evenly distributed in a reservoir along with turn-over could be decreased as well.

• 한국지진공학회논문집
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• 제24권2호
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• pp.59-65
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• 2020

The empirical Green's function method is applied to the foreshock and the mainshock of the 2016 Gyeongju earthquake to simulate strong ground motions of the mainshock and scenario earthquake at seismic stations of seven metropolises in South Korea, respectively. To identify the applicability of the method in advance, the mainshock is simulated, assuming the foreshock as the empirical Green's function. As a result of the simulation, the overall shape, the amplitude of PGA, and the duration and response spectra of the simulated seismic waveforms are similar with those of the observed seismic waveforms. Based on this result, a scenario earthquake on the causative fault of Gyeongju earthquake with a moment magnitude 6.5 is simulated, assuming that the mainshock serves as the empirical Green's function. As a result, the amplitude of PGA and the duration of simulated seismic waveforms are significantly increased and extended, and the spectral amplitude of the low frequency band is relatively increased compared with that of the high frequency band. If the empirical Green's function method is applied to several recent well-recorded moderate earthquakes, the simulated seismic waveforms can be used as not only input data for developing ground motion prediction equations, but also input data for creating the design response spectra of major facilities in South Korea.

• 한국시스템다이내믹스연구
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• 제16권1호
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• pp.25-51
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• 2015

The purpose of this paper is to analyze nutrients dynamics depending on biomass of Menyanthes trifoliata L., the endangered species, in a small closed-type wetland. In order to understand dynamics between Menyanthes trifoliata L. and eutrophication, causal loops and stock-flow diagram were constructed. The result of the model simulation was matched well with monitoring data (Menyanthes trifoliata L. biomass, TN, TP, DO). The model was simulated with 3 scenarios. In case of scenario 1, the initial value of biomass was 0mg/L, and the eutrophic state period was 77 days. In case of scenario 2, the initial value of biomass was 35.8 mg/L, and the eutrophic state lasted for 13 days. In case of scenario 3, the initial value of biomass was 71.6 mg/L, and the eutrophic state was nonexistent. The scenario 3 was selected as planting plan of Menyanthes trifoliata L. Through this study, planting design with an endangered plant was developed to control eutrophication in small closed-type wetland.

• Smart Structures and Systems
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• 제4권5호
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• pp.641-653
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• 2008

This paper proposes a practical and realistic method to establish an optimal lifetime maintenance strategy for deteriorating bridges by considering the life-cycle performance as well as the life-cycle cost. The proposed method offers a set of optimal tradeoff maintenance scenarios among other conflicting objectives, such as minimizing cost and maximizing performance. A genetic algorithm is used to generate a set of maintenance scenarios that is a multi-objective combinatorial optimization problem related to the lifetime performance and the life-cycle cost as separate objective functions. A computer program, which generates optimal maintenance scenarios, was developed based on the proposed method using the life-cycle costs and the performance of bridges. The subordinate relation between bridge members has been considered to decide optimal maintenance sequence and a corresponding algorithm has been implemented into the program. The developed program has been used to present a procedure for finding an optimal maintenance scenario for steel-girder bridges on the Korean National Road. Through this bridge maintenance scenario analysis, it is expected that the developed method and program can be effectively used to allow bridge managers an optimal maintenance strategy satisfying various constraints and requirements.

• Asian Journal of Innovation and Policy
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• 제9권2호
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• pp.133-144
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• 2020

Korean economy has experienced a very rapid growth largely due to the change of the innovation system since the last half century. The recent outbreak of COVID-19 impacts the global economy as well as Korea's innovation system. In order to understand the influence of the shock to the Korean technological system, we have forecast the future of the system combining qualitative and quantitative techniques such as expert panel, cross impact analysis, and scenario planning. According to the results, we have identified 39 driving forces influencing the change of Korea's technological innovation system. Four scenarios have been suggested based on the predetermined factors and core uncertainties. In other words, uncertainties of emergence of the regions and global value chains generate four scenarios: regional growth, unstable hope, returning to the past, and regional conflicts. The 'regional growth' scenario is regarded as the most preferable, whereas the 'regional conflicts' scenario is unavoidable. In conclusion, we put forward some policy implications to boost the regional innovation system by exploiting the weakened global value chains in order to move on to the most preferable scenario away from the return to the past regime.

• 한국산학기술학회논문지
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• 제11권5호
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• pp.1873-1880
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• 2010

최근 인간 중심의 정보화 사회가 USN 기술의 발전과 더불어 유비쿼터스 컴퓨팅 사회로 급격히 변모하고 있다. USN 응용 웹 서비스는 USN 기술을 이용하여 환경과 상황의 자동 인지를 통해 편리함을 제공하며 실시간 관리를 통해 최적의 서비스를 제공함으로써 인간 생활의 편리성과 안전성을 향상시킨다. 따라서 이러한 기술을 이용한 USN 응용 웹 서비스는 생활 전반에 다양하게 적용된다. 본 논문에서는 USN을 기반으로 수집된 메타 데이터와 센싱 데이터에 대하여 사용자들의 요구사항을 분석하여 시나리오를 구현하고 각 시나리오에 가장 효과적으로 대응 할 수 있는 시각화를 구현하였다.

• 시스템엔지니어링학술지
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• 제15권1호
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• pp.51-59
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• 2019

After Fukushima Dai-ichi NPP accident, the need for implementation of diverse and flexible coping strategies (FLEX) became evident. However, to ensure the effectiveness of the safety strategy, it is essential to quantify the uncertainties associated with the station blackout (SBO) scenario as well as the operator actions. In this paper, a systems engineering approach for uncertainty analysis (UA) of a SBO scenario in advanced pressurized water reactor is performed. MARS-KS is used as a best estimate thermal-hydraulic code and is loosely-coupled with Dakota software which is employed to develop the uncertainty quantification framework. Furthermore, the systems engineering approach is adopted to identify the requirements, functions and physical architecture, and to develop the verification and validation plan. For the preliminary analysis, 13 uncertainty parameters are propagated through the model to evaluate the stability and convergence of the framework. The developed framework will ultimately be used to quantify the aleatory and epistemic uncertainties associated with an extended SBO accident scenario and assess the coping capability of APR1400 and the effectiveness of the implemented FLEX strategies.

• 한국가스학회지
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• 제17권2호
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• pp.59-69
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• 2013

본 연구에서는 가스전의 추가 생산정 위치선정을 위해 고속의 연산이 가능한 인공신경망을 이용하여 저류 전산시뮬레이터를 개발하였다. 입출력자료와 알고리즘을 설계하였으며, 개발한 시뮬레이터를 이용하여 가스전의 추가 생산정 위치선정을 위한 연구를 수행하였다. 입력값은 생산시간, 생산정간 상관관계, 추가 생산정 위치좌표, 생산성 잠재력, 함수적 연관관계, 저류층 압력으로 구성하였으며, 출력값은 생산량과 함께 공저압력을 동시에 사용하였다. 20가지의 생산정 위치 시나리오에 대해 학습을 수행한 결과, 생산량의 상관계수 값은 0.99, 공저압력은 0.98로 상관관계가 매우 높은 것으로 확인되어 인공신경망 시뮬레이터의 타당성이 검증되었다. 가스전에서 최대공급계약량 유지시점을 산출함으로써 생산정 위치에 따른 생산성을 분석하였다. 그 결과 시나리오 C-1이 최대공급계약량 유지기간이 가장 짧았으며, 시나리오 A-1이 가장 오랫동안 유지시킬 수 있는 것으로 산출되었다. 결론적으로, 시나리오 A가 생산성에 영향을 받는 인자를 포함한 시나리오 B, C보다 최대 21% 더 최대공급계약량을 유지시킬 수 있는 것으로 확인되었다. 따라서 생산성에 영향을 미치는 요소를 종합적으로 고려하여 생산정의 위치를 선정해야 생산량을 극대화 할 수 있다. 본 인공신경망 시뮬레이터를 이용 시 생산기간동안 생산량과 공저압력 변화를 동시에 비교 분석하는 것이 가능하여 다양한 최적화 모델에 전위모델로 사용하는 것이 가능하다.