• Nuclear Engineering and Technology
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• 제51권5호
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• pp.1297-1306
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• 2019

Probabilistic safety assessments (PSA) have been used for several decades to visualize the risk level of commercial nuclear power plants (NPPs). Since the role of a human reliability analysis (HRA) is to provide human error probabilities for safety critical tasks to support PSA, PSA quality is strongly affected by HRA quality. Therefore, it is important to understand the underlying limitations or problems of HRA techniques. For this reason, this study conducted a survey among 14 subject matter experts who represent the HRA community of domestic Korean NPPs. As a result, five significant HRA issues were identified: (1) providing a technical basis for the K-HRA (Korean HRA) method, and developing dedicated HRA methods applicable to (2) diverse external events to support Level 1 PSA, (3) digital environments, (4) mobile equipment, and (5) severe accident management guideline tasks to support Level 2 PSA. In addition, an HRA method to support multi-unit PSA was emphasized because it plays an important role in the evaluation of site risk, which is one of the hottest current issues. It is believed that creating such a catalog of prioritized issues will be a good indication of research direction to improve HRA and therefore PSA quality.

• 한국컴퓨터정보학회논문지
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• 제10권6호
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• pp.337-344
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• 2005

원자력 발전소의 확률론적 안전성 평가(PSA)를 수행하기 위해서는 여러 가지 분야의 다양한 데이터가 필요하다. 그러므로 PSA의 수행 및 검토에 있어, 효과적인 자료의 관리가 필수적이라 할 수 있다. 한국 원자력연구소에서는 PSA 관련 모든 정보를 손쉽게 관리하기 위하여, PSA 정보 시스템(AIMS)을 개발하고 있다 AIMS는 PSA 분석에 필요한 모든 관련 문서와 모델을 통합하여, PSA평가를 손쉽게 수행할 수 있도록 개발한 시스템이다. 본 논문에서는 PSA정보 시스템의 개발 과정 및 데이터베이스 설계 그리고 입출력 시스템의 설계 및 구현에 관하여 기술하였다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2004년도 추계학술발표회 발표논문집
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• pp.413-414
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• 2004

• Nuclear Engineering and Technology
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• 제39권3호
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• pp.215-220
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• 2007

The existing flooding Probabilistic Safety Analysis(PSA) was updated to reflect the Korean plant specific operating experience data into the flooding frequency to improve the PSA quality. Both the Nuclear Power Experience(NPE) database and the Korea Nuclear Pipe Failure Database(NuPIPE) databases were used in this study, and from these databases, only the Pressurized Water Reactor(PWR) data were used for the flooding frequencies of the flooding areas in the primary auxiliary building. With these databases and a Bayesian method, the flooding frequencies for the flooding areas were estimated. Subsequently, the Core Damage Frequency(CDF) for the flooding PSA of the Ulchin(UCN) unit 3 and 4 plants based on the Korean Standard Nuclear Power Plant(KSNP) internal full-power PSA model was recalculated. The evaluation results showed that sixteen flooding events are potentially significant according to the screening criterion, while there were two flooding events exceeding the screening criterion of the existing UCN 3 and 4 flooding PSA. The result was compared with two kinds of cases: (1) the flooding frequency and CDF from the method of the existing flooding PSA with the PWR and Boiled Water Reactor(BWR) data of the NPE database and the Maximum Likelihood Estimate(MLE) method and (2) the flooding frequency and CDF with the NPE database(PWR and BWR data), NuPIPE database, and a Bayesian method. From the comparison, a difference in CDF results was revealed more clearly between the CDF from this study and case (2) than between case (1) and case (2). That is, the number of flooding events exceeding the screen criterion further increased when only the PWR data were used for the primary auxiliary building than when the Korean specific data were used.

• 과학기술학연구
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• 제13권1호
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• pp.77-109
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• 2013

현재 의료체계의 주된 변화로 근거중심의학(Evidence-based Medicine: EBM)의 전지구적확산을 꼽을 수 있다. 최근 STS 연구들은 EBM이 실제 의학 실행 속에서 어떻게 사용되고 작동하는지에 대한 검토를 수행했는데, 이 글은 이러한 맥락 속에서 전립선암 특이항원(Prostate-specific Antigen: PSA) 의 조기진단 검사 도구 사용 여부를 둘러싸고 미국에서 벌어진 논쟁을 추적한다. 본 연구는 EBM이 PSA 검사 조기진단의 지지자와 반대자 양측에서 논쟁의 자원으로 이용되었으며, 그 과정에서 '확고한 과학적 기준'을 제시할 것으로 기대되던 EBM의 과학적 증거 위계가 행위자들의 의도에 따라 사실상'유연하게' 해석되고 동원되었음을 보일 것이다. 나아가, 이 글은 현재 EBM이 PSA 검사 반대자를 지지하는 것처럼 보이는 일은 삶의 질이라는 가치가 EBM의 체계 내에 주요한 변수로 부상하는 역사적 맥락에 의해 만들어진 결과임을 드러낼 것이다. 본 사례 연구는 EBM 시대에 의료기술에 관한 논쟁을 검토하는 연구자들이 EBM이라는 대상을 주어진 것으로 간주하기 보다는 논쟁 속에서 맥락화하여 논쟁과 함께 분석해야 함을 시사한다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제9권4호
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• pp.331-341
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• 2009

PSA (Pressure Sensitive Adhesive) is used for various purposes in electronic appliances such as double-sided tape for fitting parts, product's name plate, and surface protecting film, and so forth. In several kinds of PSAs, this paper dealt with the failure analysis of PET (Polyethylene Terephthalate) acrylic adhesive tapes. The causes of interface failure were investigated through the test of adhesive strength, thickness, and structure. And test standard methods to prevent recurrences were established.

• Journal of Korean Biological Nursing Science
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• 제22권2호
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• pp.71-80
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• 2020

Purpose: The purpose of this study was to review primary research exploring the correlations between the levels of serum testosterone and the prostate-specific antigen (PSA) in healthy men without prostate diseases. Methods: An integrative review was conducted using the Whittemore & Knafle (2005) framework. The keywords, 'testosterone & prostate-specific antigen', 'testosterone & PSA' and 'healthy men' were used to search peer-reviewed publications in six databases. Among 1,959 searched articles, eleven articles were selected after excluding articles that do not meet inclusion criteria. Literature quality was moderate (Level 3). Results: As a result of this study, it was confirmed through the nine articles that healthy adult men showed no significant correlation between the serum testosterone and the PSA. Conversely, two articles presented that the serum PSA correlate positively with the testosterone. In particular, it is inferred that the effect of the serum testosterone and the PSA secreted into a 24-hour circadian rhythm with different amplitudes and slopes would have had great influence. However, it does not consider the factors affecting the testosterone and the PSA, such as race, liver disease, and BMI, so there is insufficient empirical data to clearly explain the relationship between the testosterone and the PSA. Conclusion: The correlation between the serum testosterone and the PSA in healthy adult men is insignificant in relation to the circadian rhythm of the testosterone and the PSA secretion. It is that a large-scale study including various influencing factors using new biochemical indicators such as pro PSA be conducted in the future.

• Nuclear Engineering and Technology
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• 제37권3호
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• pp.207-220
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• 2005

Nuclear power plants (NPP) are complex socio-technological systems that rely on the success of both hardware and human components. Empirical studies of plant operating experience show that human errors are important contributors to accidents and incidents, and that organizational factors play an important role in creating contexts for human errors. Current probabilistic safety assessments (PSA) do not explicitly model the systematic contribution of organizational factors to safety. As some countries, like the United States, are moving towards increased use of risk information in the regulation and operation of nuclear facilities, PSA quality has been identified as an area for improvement. The modeling of human errors, and underlying organizational weaknesses at the root of these errors, are important sources of uncertainty in existing PSAs and areas of on-going research. This paper presents a review of research into the following questions: Is there evidence that organizational factors are important to NPP safety? How do organizations contribute to safety in NPP operations? And how can these organizational contributions be captured more explicitly in PSA? We present a few past incidents that illustrate the potential safety implications of organizational deficiencies, some mechanisms by which organizational factors contribute to NPP risk, and some of the methods proposed in the literature for performing root-cause analyses and including organizational factors in PSA.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 추계학술발표회
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• pp.536-537
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• 2005

• 한국압력기기공학회 논문집
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• 제10권1호
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• pp.51-55
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• 2014

Based on the results of Probabilistic Safety Assessment(PSA) for a Nuclear Power Plant (NPP), Common Cause Failure(CCF) events have been recognized as one of the main contributors to the risk. Also, the CCF data and estimation method used in domestic PSA models have been pointed out as an issue with respect to the quality. The existing method of MGL and non-staggered testing even widely used were considered conservative in estimating the safety and had a limited capability in uncertainty analyses. Therefore, this paper presents the CCF estimation using a new generic data source and Alpha factor method. The analyses showed that Alpha factor and staggered method are effective in estimating the CCF contribution and risk insights of reference plant. This method will be a common bases for the optimization of new design for the construction plants as well as for the updating of safety assessment on the operating nuclear power plants.