• Journal of the Korean Society of Safety
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• v.32 no.6
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• pp.1-8
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• 2017

P-PIE is a program developed to estimate failure probability of pipes and pressure vessels considering fatigue and stress corrosion crack growth. Using the program, crack growth simulation was performed with an initially existing crack in order to examine the effects of initial crack depth distribution on the leak probability of pipes. In the simulation stress corrosion crack growth was considered and several crack depth distribution models were used. From the results it was found that the initial crack depth distribution gives great effect on the leak probability of pipes. The log-normal distribution proposed by Khaleel and Simonen gives lower leak probability compared other exponential distribution models. The effects of the number and the quality of pre-service and in-service inspections on the leak probability were also examined and it was recognized that the number and the quality of pre-service and in-service inspections are also give great effect on the leak probability. In order to reduce the leak probability of pipes in plants it is very important to improve the quality of inspections. When in-service inspection is performed every 10 years and the quality of inspection is above the very good level, the leak probability shows nearly constant value after the first inspection for an initially existing crack.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.859-866
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• 2001

During the Pre-service Inspection for Wolsong Unit 3&4 in 1997/1998 respectively, 17 Distorted Roll Transition indications(over expanded beyond tubesheet secondary face) were identified at the Unit 4 (S/G B, D). Six(6) tubes out of these tubes were plugged in 1998. However the first Periodic Inspection identified additional 110 indications in 1999 and 2000. The additionally identified 110 indication call, not reported at the Pre-service Inspection, are; 2 Not-Finally-Expanded-Tubes and 108 Distorted Roll Transition tubes. Design limit of each Steam Generator tube Plugging is 6.4%. Plugging was performed by the Steam Generator manufacturer under the warranty. When Distorted Roll Transition indications were first identified on the Unit 4 in 1998 the degree of Over-expansion was measured using an inner dial-gage to make the disposition of Nonconformance report. 2 Not-Finally-Expanded-Tubes were plugged and 10 tubes out of 108 Distorted Roll Transition Tubes were also plugged as a preventive measure.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.6 no.2
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• pp.9-15
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• 2010

US NRC issued rulemaking of 10CFR50.55a to perform the Perservice and Inservice inspection for Reactor Vessel Head Penetration Nozzle of US Nuclaer plant. The rulemaking was required the EPRI Demonstration to verify the NDE technique performing special Ultrasonic examination. In order to meet this requirement, the UT and ECT procedures was demonstrated and the NDE personnel were qualified by EPRI. In this paper, the NDE technique and analysis method are described the Preservice inspection for the Palo Verde #1/2/3 Replacement Reactor Vessel Head Penetration Nozzle using the qualified procedures and personnel.

• Proceedings of the KIEE Conference
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• 2005.07e
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• pp.112-114
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• 2005

It is obvious that electrical safety cannot be secured soley by the efforts from public sector including government. With the global trend of deregulation as WTO/TBT agreement comes into effect, foreign countries strive to minimize unnecessary and inefficient regulations in every field by sharing responsibilities with the privae sector to secure international competency in trade. To this same end, in this paper 2 level approach plan is suggested to pave the way to the self-security system in electrical field by introducing self-reliance safety system by stage for pre-service inspection on the electrical installations for private use based on product requirements in terms of performance.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.4
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• pp.390-395
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• 2004

The iSTMS is a web-based integrated information system supporting Pre-Service and In-Service Inspection(PSI/ISI) processes for the nuclear power plants of KHNP(Korea Hydro & Nuclear Power Co. Ltd.). The system provides a full spectrum coverage of the inspection processes from the planning stage to the final report of examination in accordance with applicable codes, standards, and regulatory requirements. The major functions of the system includes the inspection planning, examination, reporting, project control and status reporting, resource management as well as objects search and navigation. The system also provides two dimensional or three dimensional visualization interface to identify the location and geometry of components and weld areas subject to examination in collaboration with database applications. The iSIMS is implemented with commercial software packages such as database management system, 2-D and 3-D visualization tool, etc., which provide open, updated and verified foundations. This paper describes the key functions and the technologies for the implementation of the iSIMS.

• Industrial Engineering and Management Systems
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• v.12 no.3
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• pp.281-287
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• 2013

In this paper, we introduce a roots method that uses the roots inside the unit circle of the associated characteristics equation to evaluate the steady-state system-length distribution at three epochs (pre-arrival, arbitrary, and post-departure) and sojourn-time distribution in GI/PH/1 queueing model. It is very important for an air base to inspect airplane oil because low-quality oil leads to drop or breakdown of an airplane. Since airplane oil inspection is composed of several inspection steps, it sometimes causes train congestion and delay of inventory replenishments. We analyzed interarrival time and inspection (service) time of oil supply from the actual data which is given from one of the ROKAF's (Republic of Korea Air Force) bases. We found that interarrival time of oil follows a normal distribution with a small deviation, and the service time follows phase-type distribution, which was first introduced by Neuts to deal with the shortfalls of exponential distributions. Finally, we applied the GI/PH/1 queueing model to the oil train congestion problem and analyzed the distributions of the number of customers (oil trains) in the queue and their mean sojourn-time using the roots method suggested by Chaudhry for the model GI/C-MSP/1.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.11 no.2
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• pp.13-19
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• 2015

Steam generator is one of the most important component of nuclear power plant, and it's integrity and reliability are to be assured to high level by pre-service inspection and in-service inspection. To improve the reliability of steam generator heat exchanger tubes and to secure the management of nuclear power plant safely, KHNP CRI recently has developed eddy current testing system for steam generator. KHNP CRI have performed a series of experimental verification and field application to confirm the performance of the developed ECT system in accordance with ASME Code requirements. The ECT system consists of a remote data acquisition unit, an ECT signal acquisition and analysis software, a water chamber robot controller and a probe push-puller. In this paper, we will details of the developed ECT system and the software and their experimental performance. And also we will report the field applying performance and the issues for further steps.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.212-218
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• 2000

The importance and role of pre-/in-service inspection(PSI/ISI) for nuclear power plant(NPP) components are intimately related to plant design, safety, reliability, operation, etc. In this paper, for an effective and efficient management of large amounts of PSI/ISI data in NPPs, an intelligent database program(WS-IDPIN) for PSI/ISI data management of NPP was developed. WS-IDPIN program enables the prompt extraction of previously conducted PSI/ISI conditions and results so that the time-consuming data management, painstaking data processing and analysis in the past are avoided. Furthermore, development of ISI UT auto flaw evaluation and acceptance module based on ASME Code Sec. XI were presented. This module can be used for any angle beam examination from flat plate to spherical shapes as selected by the proper azimuthal angle. This program can be further developed as a unique PSI/ISI data management expert system.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.4 no.2
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• pp.46-49
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• 2008

NDE(Nondestructive examination) detects a flaw or discontinuity in materials. Flaws detected by the pre-service or in-service examinations shall be sized for the purpose of analysis and repair. A flaw that is initiated from the surface is difficult to determine its depth by NDE. The depth of the surface flaw can be measured using an ultrasonic diffracted wave. To find the optimum standard for ultrasonic parameter(For example, frequency & size of transducer), a mock-up test and simulation were established and studied. This inspection technology may show the depth sizing possibility of the flaw down to nearly two(2) mm.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2761-2763
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• 2002

원자력발전소에서는 건설완료 단계에서 기기, 배관 및 각종 지지구조물에 대하여 PSI(Pre-Service Inspection)를 실시하여 시공된 설비의 건전성을 점검하고, 운영중에는 주기적으로 시간의 경과에 따른 취약화 정도를 비과괴검사로 감시 및 평가하는 ISI (In-Service Inspection)를 실시하여 안전성 관련 설비의 건전성을 점검하고 있다. 이 과정에서 방대한 양의 검사데이터가 생산되며 원전 가동년수가 증가함에 따라 검사자원을 체계적으로 관리하고 자동화 할 수 있는 시스템 개발이 필요하게 되었다. 본 논문에서는 PSI/ISI 검사결과 정보관리를 비롯하여 검사 기초자료 관리 및 검사계획 수립, 파괴역학 분식 기능 등을 포함한 Web 기반의 Application 개발 사례를 소개한다. 또한 가상현실 기법을 적용하여 기존의 2차원적 DB 운영을 3차원 가상공간에서 운영할 수 있는 'Touch & Tell' 기법을 개발하고 그 구현방법을 제시한다.