• Nuclear Engineering and Technology
• /
• v.51 no.5
• /
• pp.1297-1306
• /
• 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.

• Journal of the Korea Society of Computer and Information
• /
• v.10 no.6 s.38
• /
• pp.337-344
• /
• 2005

In order to Perform a PSA. it requires a large number of data for various fields. Therefore, the effective management of the data is essential to perform and review a PSA and to maintain the quality of a PSA. Korea Atomic Energy Research Institute (KAERI) is developing a PSA information management system (AIMS: Advanced Information Management System for PSA) which enhances the accessibility to PSA information for all PSA related activities. The AIMS is a database system that stores all references and links to the information used for the PSA analysis. The AIMS consists of a database, information browsing modules and a PSA model manager. This Paper describes how we implemented such a database centered application in the view of two areas, database design and data (document) service.

• Proceedings of the Korean Nuclear Society Conference
• /
• 2004.10a
• /
• pp.413-414
• /
• 2004

• Nuclear Engineering and Technology
• /
• v.39 no.3
• /
• pp.215-220
• /
• 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.

• Journal of Science and Technology Studies
• /
• v.13 no.1
• /
• pp.77-109
• /
• 2013

The global diffusion of Evidence-Based Medicine (EBM) is changing the landscape of medicine and the healthcare system. STS scholars have shown how EBM works when put into practice. In continuing to add to the literature of previous scholars, this paper traces the historical process and debate over Prostate-Specific Antigen (PSA) testing as an early screening test for prostate cancer in the U.S. This study will reveal that both pros and cons of the testing using EBM as a crucial resources of the debate, and in the process both 'flexibly' interpret and mobilize the hierarchy of scientific evidence for EBM despite the fact the hierarchy is imagined to being scientific criteria that is rigid. Furthermore, this paper will argue that this phenomenon, for which EBM currently seems to support the cons side of PSA screening, was constructed in the context of appraisal of the value 'quality of life' in the EBM system. This case study proposes that those who study the debate of medical technology in the EBM era should contextualize and analyze EBM as part of this debate rather than simply taking EBM for granted.

• Journal of Applied Reliability
• /
• v.9 no.4
• /
• pp.331-341
• /
• 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
• /
• v.22 no.2
• /
• pp.71-80
• /
• 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
• /
• v.37 no.3
• /
• pp.207-220
• /
• 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.

• Proceedings of the Korean Nuclear Society Conference
• /
• 2005.10a
• /
• pp.536-537
• /
• 2005

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.10 no.1
• /
• pp.51-55
• /
• 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.