• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.7 no.4
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• pp.57-62
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• 2011

As NPPs' operating times increase, the integrity of nuclear components is continually degraded due to aging effects of systems, structures and components. In addition, for the case of continued operation beyond design life, additional aging effects occurred during the extended operating period lead to more degradation of the integrity of nuclear components. Therefore, it is very important to mange and evaluate the aging to secure the safety of NPPs. Wolsong unit 1 is approaching to its design life of 30 years in 2012. The license renewal documents for continued operation of Wolsong unit 1 Is under reviewing now. In this paper, regulatory technologies for continued operation of Wolsong unit 1 developed by KINS will be introduced. That technologies include the safety review guidelines, regulatory guides for aging management program and regulatory program for audit calculation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.4
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• pp.495-499
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• 2010

In this paper, the regulatory guidelines for the continued operation of the CANDU reactor in Korea were introduced. Wolsong Unit 1, which is a CANDU 600 reactor in Korea, will reach its design life of 30 years in 2012. A licensee who wants to operate a nuclear power plant beyond its design life should submit reports of periodic safety reviews (PSRs) conducted on the basis of 11 safety factors. In addition, the licensee should provide the following: (1) scoping and screening results for aging management, (2) aging management program, (3) TLAA, including the continued operation term, (4) operation-experience feedback, and (5) important safety-research results. In this study, 54 regulatory guidelines for the five above-mentioned items for the CANDU reactor in Korea were developed.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.7 no.2
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• pp.14-20
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• 2011

The end of design lifetime for Wolsong unit 1 will be reached on 20th November in 2012. So the license renewal documents for the continuous operation of Wolsong unit 1 is under reviewing now. Major components of primary system such as pressure tubes, feeder pipes including delayed neutron monitoring system tubing are being replaced and many components of secondary system are also being repaired. In this paper, the assessment on the wear degradation of delayed neutron monitoring system tubing(on the other hand, DN tube was called) was performed for the ageing management of the same component. The wear defects of this component was one of causes that resulted in heavy water leakage accidents. Therefore design specifications of Wolsong uint 1 and heavy water leakage accidents of pressurized heavy water reactors were reviewed and causes of wear defect for DN tubes were analyzed. Wear propagation equations based on the heavy water leakage history were made and the proper repairing time was possible to be expected if the continued operation was considered. Finally design change items of DN tubes that were conducted for the long term operation of Wolsong unit 1 are introduced.

• Nuclear Engineering and Technology
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• v.40 no.4
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• pp.277-284
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• 2008

Recently, the long-term operation of a nuclear power plant beyond its licensed term has become a worldwide trend as long as the safety of the plant is maintained in the extended period. Kori Unit 1, the oldest PWR in Korea, is the foremost example of this type of long-term operation in Korea. Comprehensive technical evaluation of the long-term operation of this plant was completed to confirm the overall safety of the plant. The technical evaluation included a review of PSR results, an assessment on aging management programs and time limited aging analyses, and a statement of radiological impact on the environment. Based on all of the results of the technical evaluation activities, Kori Unit 1 was approved to operate for an additional 10 years beyond its original design life of 30 years.

• Nuclear Engineering and Technology
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• v.42 no.5
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• pp.590-599
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• 2010

Recently, efficient operation and practical management of power plants have become important issues in the nuclear industry. In particular, typical aging parameters such as stress and cumulative usage factor should be determined accurately for continued operation of a nuclear power plant beyond design life. However, most of the major components have been designed via conservative codes based on a 2-D concept, which do not take into account exact boundary conditions and asymmetric geometries. The present paper aims to suggest an effective fatigue evaluation methodology that uses a prototype of the integrated model and its transfer functions. The validity of the integrated 3-D Finite Element (FE) model was proven by comparing the analysis results of individual FE models. Also, mechanical and thermal transfer functions, known as Green's functions, were developed for the integrated model with the standard step input. Finally, the stresses estimated from the transfer functions were compared with those obtained from detailed 3-D FE analyses results at critical locations of the major components. The usefulness of the proposed fatigue evaluation methodology can be maximized by combining it with an on-line monitoring system, and this combination, will enhance the continued operations of old nuclear power plants.

• Journal of Information Technology Services
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• v.12 no.4
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• pp.41-57
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• 2013

As the usage of SNS has grown dramatically over the last years, it has been used in various sectors not just a tool for communication. In particular, corporate companies actively use Facebook as a tool for corporate marketing. Corporate companies communicate with their customers by providing service or events information. In this study, empirical analysis was carried out on corporate companies that are using Facebook as a marketing tool, thus finding out the influencing factors in continued usage of Facebook Fan Page users. In addition, analysis of the factors will be investigated according to continued usage of the users, where the user's intention will differ depending on how corporate companies operate and deal with the Facebook Fan Page. Factors affecting the user's satisfaction, perceived usefulness, and perceived playfulness were deducted through the analysis of the existing literature study on corporate company's continued intention on the usage of Facebook Fan Page. Accordingly, factor affecting this such as relationship, speed, content diversity, which are the media characteristics of the Facebook were deducted and finally hypothesized. In addition, the type of corporate company's Facebook Fan Page was divided into event type, communication type, information service type. And hence investigated the factors that differed from the continued usage depending on the type. Results analysis shows that perceived usefulness affected only relationship, speed, content diversity. Furthermore, analysis shows that corporate company's Fan Page of communication and event types are the factors that affect the usage intention which meant it only affected the perceived enjoyment. On the basis of this study, we are able to present an implication of value where corporate company use it as a marketing tool, through factors from continued usage of coroporate company's Facebook Fan Page users.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.05a
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• pp.415-423
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• 2003

Korea Electric Power Research Institute(KEPRI) had worked a comprehensive Plant Lifetime Management (PLiM) project for a CANDU plant in corporation with Korea Hydro and Nuclear Power(KHNP). The project had been performed to understand the aging status of major components screened from the plant and to address provisions for the continued operation over its design life. A feasibility of the continued operation was reviewed in the aspects of technology, economics, and regulatory environments. This paper introduces general approach of aging assessment, screening of critical components and an experience of aging assessment for an example of fuel channel that is the most critical component in CANDU plant.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.131-138
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• 2001

This paper describes the result of endurance test of the brake system of the Korean EMU on the Sangju test track. The purpose of the test is to prove the endurance of brake system. Test conditions are more severe than actual operation on the commercial line. As of October, test result is good without severe problems. 100,000km of test operation will be continued by the end of this year to check the endurance of the brake system.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.6 no.2
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• pp.28-33
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• 2010

As a part of license renewal for the continued operation of Wolsong unit 1, the periodic safety review report was submitted near the end of design lifetime, 2012, and now is under reviewing. Major components of primary system such as pressure tubes, feeder pipes and so on are being replaced and many components of secondary system are also being repaired. So the license renewal of Wolsong unit 1 is expected to be acquired without significant issues. But on the other hand, steam generators of Wolsong unit 1 had the good performance and therefore the replacement and repair for the steam generator are not needed. Recently it is reported that some cracks were detected in a few of european steam generator with Alloy 800 tubes and the cause of cracks was the outer diameter stress corrosion cracking(ODSCC) due to the concentration of chemical impurities on the outer surface of tube. Accordingly the overall review on this issue was performed. The long-term operation is likely to results to form the concentration mechanism for the tube corrosion as the sludge build-up in the secondary side of steam generator and the crack in the crevice between tube and tube-sheet and expansion transitions is apt to be occurred. In this paper, the history of steam generator inspection and operation of Wolsong unit 1 are reviewed and the reliability of steam generator tube is evaluated and the steam generator aging management program for Wolsong unit 1 is introduced.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1413-1414
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• 2003

Interannual variability in the patterns of satellitederived pigment concentrations, sea-level height anomaly, sea surface temperature anomaly, and zonal wind anomaly are observed during the 2002-2003 El Ni${\tilde{n}}$o. The largest spatial extent of the phytoplankton bloom was recovery from El Ni${\tilde{n}}$o over the equatorial Pacific. The evolution towards a warm episode (El Ni${\tilde{n}}$o) started from spring of 2002 and continued during January 2003, while equatorial Sea Surface Temperature Anomaly (SSTA) remained greater than +1$^{\circ}$C in the central equatorial Pacific. The EOS (Earth Observing System) and OSMI (Ocean Scanning Multispectral Imager) data are used for detection of dramatic changes in the patterns of pigment concentration during El Ni${\tilde{n}}$o.