• Nuclear Engineering and Technology
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• 제40권5호
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• pp.349-364
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• 2008

Over the years, probabilistic risk assessment (PRA) research activities conducted at the U.S. Nuclear Regulatory Commission (NRC) have played an essential role in support of the agency's move towards risk-informed regulation. These research activities have provided the technical basis for NRC's regulatory activities in key areas; provided PRA methods, tools, and data enabling the agency to meet future challenges; supported the implementation of NRC's 1995 PRA Policy Statement by assessing key sources of risk; and supported the development of necessary technical and human resources supporting NRC's risk-informed activities. PRA research aimed at improving the NRC's understanding of risk can positively affect the agency's regulatory activities, as evidenced by three case studies involving research on fire PRA, human reliability analysis (HRA), and pressurized thermal shock (PTS) PRA. These case studies also show that such research can take a considerable amount of time, and that the incorporation of research results into regulatory practice can take even longer. The need for sustained effort and appropriate lead time is an important consideration in the development of a PRA research program aimed at helping the agency address key sources of risk for current and potential future facilities.

• Nuclear Engineering and Technology
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• 제41권10호
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• pp.1361-1374
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• 2009

Due to the need of data for a Human Reliability Analysis (HRA), a number of data collection efforts have been undertaken in several different organizations. As a part of this effort, a human error analysis that focused on a set of simulator records on a Steam Generator Tube Rupture (SGTR) scenario was performed by using the Human Event Repository and Analysis (HERA) system. This paper summarizes the process and results of the HERA analysis, including discussions about the usability of the HERA system for a human error analysis of simulator data. Five simulated records of an SGTR scenario were analyzed with the HERA analysis process in order to scrutinize the causes and mechanisms of the human related events. From this study, the authors confirmed that the HERA was a serviceable system that can analyze human performance qualitatively from simulator data. It was possible to identify the human related events in the simulator data that affected the system safety not only negatively but also positively. It was also possible to scrutinize the Performance Shaping Factors (PSFs) and the relevant contributory factors with regard to each identified human event.

• 한국생활과학회지
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• 제21권5호
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• pp.819-835
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• 2012

The purpose of this study was to develop and test the validity of an assessment scale for determining the competency of early childhood teachers practicing unification education. For this purpose, an evaluation scale was constructed and then tested for reliability and validity. Participants for this study included 266 early childhood teachers in the unification education field. In order to the measure reliability and validity of this scale, Exploratory Factor Analysis and Confirmatory Factor Analysis were conducted with SPSS 18.0 and AMOS. The result of this study identified four principal factors: 1) Instruction skills, 2) Evaluation, 3) Attitude, and 4) Knowledge. The results of this study supported the scale's reliability and legitimacy as a valid instrument for the evaluation of early childhood teacher's competence in unification education.

• Nuclear Engineering and Technology
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• 제54권5호
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• pp.1686-1697
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• 2022

As a part of probabilistic risk (or safety) assessment (PRA or PSA) of nuclear power plants (NPPs), the primary role of human reliability analysis (HRA) is to provide credible estimations of the human error probabilities (HEPs) of safety-critical tasks. Accordingly, HRA community has emphasized the accumulation of HRA data to support HRA practitioners for many decades. To this end, it is critical to resolve practical problems including (but not limited to): (1) how to collect HRA data from available information sources, and (2) how to inform HRA practitioners with the collected HRA data. In this regard, the U.S. Nuclear Regulatory Commission (NRC) and Korea Atomic Energy Research Institute (KAERI) independently initiated two large projects to accumulate HRA data by using full-scale simulators (i.e., simulator data). In terms of resolving the first practical problem, the NRC and KAERI developed two dedicated HRA data collection systems, SACADA (Scenario Authoring, Characterization, And Debriefing Application) and HuREX (Human Reliability data EXtraction), respectively. In addition, to inform HRA practitioners, the NRC and KAERI proposed several ideas to extract useful information from simulator data. This paper is the first of two papers to discuss the technical underpinnings of the development of the SACADA and HuREX systems.

• 한국안전학회지
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• 제14권2호
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• pp.178-191
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• 1999

More than twenty methods were suggested for Human Reliability Analysis (HRA) in the field of safety analysis for Nuclear Power Plants (NPPs). However, there is still a high uncertainty on the analysis and a difficulty in performing HRA. New methods and approaches are under studying to overcome such limitations of current HRA. This paper presents some results of study to analysis limitations of current HRA in viewpoint of user, i.e., HRA analyst. The limitation analysis was based on 89 human error events modeled in a Probabilistic Safety Assessment (PSA) project for NPPs in Korea. Total 17 specific limitations were identified and categorized into seven groups. Important analysis has also been undertaken to assess the order of priority among those limitations. Finally, seven requirements with priority ranking were generated for an advanced framework and methodology of HRA.

• 한국물환경학회지
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• 제29권2호
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• pp.165-169
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• 2013

Freshwater fish intake is a critical parameter for deriving water quality criteria and water quality standards for protection of human health based on human health risk assessment. Although the freshwater fish intake parameter should be accurate and representative of Korean fish consumption for the water quality criteria to be reliable, data are limited in Korea and have low reliability. In this study, Korean National Health and Nutrition Examination Survey data from 2008-2010 were analyzed to reevaluate freshwater fish consumption. Based on these results, an average consumption rate of 3.0 g/day per person, a $90^{th}$ percentile consumption rate of 0.0 g/day per person, an average consumption rate of 65.7 g/day per fish consumer, and a $90^{th}$ percentile consumption rate of 153.4 g/day per fish consumer were proposed for derivation of water quality criteria using a conservative approach and various exposure scenarios.

• Nuclear Engineering and Technology
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• 제54권1호
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• pp.110-116
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• 2022

Human failure event (HFE) dependency analysis is a part of human reliability analysis (HRA). For efficient HFE dependency analysis, a maximum number of minimal cut sets (MCSs) that have HFE combinations are generated from the fault trees for the probabilistic safety assessment (PSA) of nuclear power plants (NPPs). After collecting potential HFE combinations, dependency levels of subsequent HFEs on the preceding HFEs in each MCS are analyzed and assigned as conditional probabilities. Then, HFE recovery is performed to reflect these conditional probabilities in MCSs by modifying MCSs. Inappropriate HFE dependency analysis and HFE recovery might lead to an inaccurate core damage frequency (CDF). Using the above process, HFE recovery is performed on MCSs that are generated with a non-zero truncation limit, where many MCSs that have HFE combinations are truncated. As a result, the resultant CDF might be underestimated. In this paper, a new method is suggested to incorporate HFE recovery into the MCS generation stage. Compared to the current approach with a separate HFE recovery after MCS generation, this new method can (1) reduce the total time and burden for MCS generation and HFE recovery, (2) prevent the truncation of MCSs that have dependent HFEs, and (3) avoid CDF underestimation. This new method is a simple but very effective means of performing MCS generation and HFE recovery simultaneously and improving CDF accuracy. The effectiveness and strength of the new method are clearly demonstrated and discussed with fault trees and HFE combinations that have joint probabilities.

• 한국산업안전학회:학술대회논문집
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• 한국안전학회 1998년도 추계 학술논문발표회 논문집
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• pp.219-224
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• 1998

확률론적 안전성 평가(Probabilistic Safety Assessment PSA)나 정량적인 위험도 평가(Quantitative Risk Assessment: QRA)에서 인간신뢰도분석(human reliability analysis)은 인간행위를 기기처럼 생각하여 전체 시스템의 안전성에 중요한 초기사건(initiating event) 이전이나 초기사건 이후 또는 초기사건을 유발하는 인간행위를 파악하고 정량화하여, 확률론적 평가의 논리구조인 사건 및 고장수목(event tree 및 fault tree)이나 사고경위 단절집합 (accident sequence outsets)에 포함시키는 것이다. (중략)

• Nuclear Engineering and Technology
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• 제51권1호
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• pp.104-115
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• 2019

Since the Fukushima Daiichi accident, there has been an emphasis on the risk resulting from multi-unit accidents. Human reliability analysis (HRA) is one of the important issues in multi-unit probabilistic safety assessment (MUPSA). Hence, there is a need to properly identify all the human and organizational factors relevant to a multi-unit incident scenario in a nuclear power plant (NPP). This study identifies and categorizes the human and organizational factors relevant to a multi-unit incident scenario of NPPs based on a review of relevant literature. These factors are then analyzed to ascertain all possible unit-to-unit interactions that need to be considered in the multi-unit HRA and the pattern of interactions. The human and organizational factors are classified into five categories: organization, work device, task, performance shaping factors, and environmental factors. The identification and classification of these factors will significantly contribute to the development of adequate strategies and guidelines for managing multi-unit accidents. This study is a necessary initial step in developing an effective HRA method for multiple NPP units in a site.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 추계학술발표회논문집(1)
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• pp.753-758
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• 1997

본 논문은 확률론적 안전성 평가(Probabilistic Safety Assessment) 에서 수행하고 있는 현존 인간 신뢰도 분석(Human Reliability Analysis)의 현황과 기법의 한계점을 설명하고, 인적오류 분석(Human Error Analysis: HEA)의 필요성과 그 내용을 제시하였다. 그리고, 현재까지 개발된 인적오류 분석 기법 중 7가지 기법을 간략히 소개하고, 각 기법의 적용 범위, 오류 분석 구조, 분석 대상, 오류 분석 범위, 기반 모형 둥에 대해서 상호 비교한 결과를 제시하였다.