• Nuclear Engineering and Technology
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• 제50권8호
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• pp.1217-1233
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• 2018

Following a surge of interest in multi-unit risk in the last few years, many recent studies have suggested methods for multi-unit probabilistic safety assessment (MUPSA) and addressed several related aspects. Most of the existing studies though focused on two-unit nuclear power plant (NPP) sites or used rather simplified probabilistic safety assessment (PSA) models to demonstrate the proposed approaches. When considering an NPP site with three or more units, some approaches are inapplicable or yield very conservative results. Since the number of such sites is increasing, there is a strong need to develop and validate practical approaches to the related MUPSA. This article provides several detailed approaches that are applicable to multi-unit Level 1 PSA for sites with up to six or more reactor units. To validate the approaches, a multi-unit Level 1 PSA model is developed and the site core damage frequency is estimated for each of four representative multi-unit initiators, as well as for the case of a simultaneous occurrence of independent single-unit initiators in multiple units. For this purpose, an NPP site with six identical OPR-1000 units is considered, with full-scale Level 1 PSA models for a specific OPR-1000 plant used as the base single-unit models.

• 한국건설관리학회논문집
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• 제15권4호
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• pp.119-127
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• 2014

본 연구는 기획단계에서 건축물의 이산화탄소 배출량 평가에 개략평가모델인 I-O LCA 모델의 활용 가능성을 파악하는 것을 목적으로 한다. 이를 위하여, I-O LCA 모델과 Hybrid LCA 모델을 정의하고, 두 LCA 모델을 이용하여 아파트 3개 단지와 3개 교육시설물에 대한 이산화탄소 배출량을 평가하고, 결과를 비교하였다. 사례분석 결과, I-O LCA 모델을 통해 산출된 이산화탄소 배출량은 Hybrid LCA 모델을 통해 산출된 이산화탄소 배출량과 상당히 유사하였다. 아파트 단지의 경우 78.2-86.3%의 유사도를 나타내었고, 학교 건축물의 경우 59.9-84.8%의 유사도를 나타내었다. 하지만, 전반적으로 I-O LCA 모델에 의해 산출된 이산화탄소 배출량은 Hybrid LCA 모델의 결과에 비해 작았다. 그럼에도 불구하고, 사례분석 결과는 총공사비를 유일한 입력요소로 하는 간단한 모델인, I-O LCA 모델이 상당히 높은 정확도를 가진다는 사실을 보여주었다. I-O LCA모델은 프로젝트의 초기 기획단계에 건축물의 이산화탄소 배출량을 예측하는데 활용될 수 있을 것으로 기대된다.

• 방사성폐기물학회지
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• 제7권3호
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• pp.183-190
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• 2009

고준위폐기물 처분장의 기본적인 기능은 단기간에 과도한 방사성핵종이 유출되는 것을 방지하는데 있다. 이를 위해서는, 처분시스템의 구성요소들과 관련된 많은 기술 기준이 개발되고 수립되어야 한다. 처분장 안전성평가는 합리적으로 단순화된 모델에 바탕을 두고 처분장의 미래 전개에 대한 정량적인 결과를 산출하므로 안전성평가는 기술기준의 하나로 간주되고 있다. 본문에서는 평가기간, 선량 제한치 및 평가의 불확실성 등을 중심으로 안전성평가와 관련된 주요국의 기술기준을 조사하였다. 특히, 미국의 기준을 조사하는 과정에서 안전성평가에서 도출된 peak dose가 선량 제한치를 충족하지 못하는 경우, 평가기간 및 peak dose에 대한 미국 규제당국의 접근방안은 참고할만한 가치가 있음을 알 수 있었다.

• 대한간호학회지
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• 제43권5호
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• pp.587-594
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• 2013

Purpose: The purpose of this study is to provide researchers with a simplified approach to undertaking exploratory factor analysis for the assessment of construct validity. Methods: All articles published in 2010, 2011, and 2012 in Journal of Korean Academy of Nursing were reviewed and other relevant books and articles were chosen for the review. Results: In this paper, the following were discussed: preliminary analysis process of exploratory factor analysis to examine the sample size, distribution of measured variables, correlation coefficient, and results of KMO measure and Bartlett's test of sphericity. In addition, other areas to be considered in using factor analysis are discussed, including determination of the number of factors, the choice of rotation method or extraction method of the factor structure, and the interpretation of the factor loadings and explained variance. Conclusion: Content validity is the degree to which elements of an assessment instrument are relevant to and representative of the targeted construct for a particular assessment purpose. This measurement is difficult and challenging and takes a lot of time. Factor analysis is considered one of the strongest approaches to establishing construct validity and is the most commonly used method for establishing construct validity measured by an instrument.

• Nuclear Engineering and Technology
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• 제42권2호
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• pp.145-150
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• 2010

The paper is describing work being developed in the frame of a 5-year IAEA Coordinated Research Programme (CRP) started in late 2005. Participants gained knowledge of modelling methodologies and experience in the development and use of rather sophisticated simulation tools in support of site characterization and performance assessment calculations. These goals were achieved by a coordinated effort, in which the advantages and limitations of numerical models are examined and demonstrated through a comparative analysis of simplified, illustrative test cases. This knowledge and experience should help them address these issues in their own country's nuclear waste program. Coordination efforts during the first three years of the project aimed at enabling this transfer of expertise and maximizing the learning experience of the participants as a group. This was accomplished by identifying common interests of the participants (i.e., Process Modelling and Total System Performance Assessment methodology), and by defining complementary tasks that are solved by the members. Synthesis of all available results by comparative assessments is planned in the coming months. The project will be completed end of 2010. This paper is summarizing activities up to November 2009.

• 한국지진공학회논문집
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• 제17권2호
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• pp.89-95
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• 2013

Structures in a nuclear power system are designed to be elastic even under an earthquake excitation. However a structural component such as an isolator shows inelastic behavior inherently. For the seismic assessment of nonlinear structures, response history analysis should be performed. In this study, the response of base isolation system was analyzed by response history analysis for the seismic performance assessment. Firstly, several seismic assessment criteria for a nuclear power plant structure were reviewed for the nonlinear response history analysis. Based on these criteria, the spectrum matched ground motion generation method modifying a seed earthquake ground motion time history was adjusted. Using these spectrum matched accelerograms, the distribution of displacement responses of the simplified base isolation system was evaluated. The resulting seismic responses excited by the modified ground motion time histories and the synthesized time history generated by stochastic approach were compared. And the response analysis of the base isolation system considering the different intensities in each orthogonal direction was performed.

• 전기의세계
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• 제27권1호
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• pp.49-55
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• 1978

This paper describes a computer method for power system planning. Power system planning was usually studied through individual programs. Because of the laborious work involved in data preparation, the increase of task for power system planning and the time required for the detailed analysis of results, the available time for assessment and decision making has been sacrificed. In order to improve the above situation, the use of data base techniques an the simplified evaluation of the presented programs were newly developed. This program has been used successfully for the routine of power system planning in Korea Electric Company. In addition, this paper describes some results of analysis and evaluation of power system planning in KECO.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2011년도 전기공동학술대회 논문집
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• pp.309-309
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• 2011

This paper outlines extraction potential of tidal stream resources from the simplified channel in which flow is driven by a head difference between inlet and outlet. Energy extraction alters the flow within a simple channel, and extraction of 10% energy flux in a natural channel would give rise to a flow speed reduction of about 5.7%.

• KIEE International Transactions on Power Engineering
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• 제5A권2호
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• pp.186-192
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• 2005

As the power industry moves towards open competition, there has been a call for methodology to evaluate power system reliability by using customer interruption costs. This paper presents an evaluation of the interruption costs for public customers in Korea using customer survey methodology. When various research results are examined, the evaluation of direct interruption costs becomes much more simplified. Especially, in the case of public customers, it is known that the evaluation of direct interruption costs is more useful. Accordingly, this paper selected the customer survey method to evaluate the interruption costs for public customers in Korea considering interruption and customer characteristics.

• 한국항공운항학회지
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• 제20권3호
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• pp.51-56
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• 2012

The wing is a framework composed chiefly of skin, spars, ribs and can be simplified by matrix structure. In this paper, a displacement reliability of matrix structure is analysed by AFORM(Advanced First Order Reliability Method) and applicability is assessed.