• Nuclear industry
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• v.7 no.4 s.50
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• pp.91-93
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• 1987

• Nuclear industry
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• v.20 no.10 s.212
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• pp.28-31
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• 2000

• Nuclear Engineering and Technology
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• v.17 no.2
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• pp.168-183
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• 1985

• Nuclear Engineering and Technology
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• v.17 no.1
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• pp.68-82
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• 1985

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.4
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• pp.741-747
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• 2001

Three-dimensional, elastic-plastic finite element analyses for circumferential through-wall cracked pipes are performed using actual tensile data of stainless steels, for two purposes. The first one is to validate the recently-proposed enhanced reference stress (ERS) method to estimate the J-integral and COD for circumferential through-wall cracked pipes. The second one is to compare those results with the GE/EPRI estimations. It is found that the J-integral and COD estimations according to the GE/EPRI method can be very sensitive to how the stress-strain data are fitted using the Ramberg-Osgood relation. Moreover, no tendency can be found regarding the most appropriate fitting range for the Ramberg-Osgood fit. On the contrary, the J-integral and COD estimations based on the ERS method give more accurate results than the GE/EPRI estimation. The present results provide confidence in applying the proposed method to the Leak-Before-Break(LBB) analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.6
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• pp.890-897
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• 2003

This paper compares engineering estimation schemes of C＊ and creep COD for circumferential and axial through-wall cracked pipes at elevated temperatures with detailed 3-D elastic-creep finite element results. Engineering estimation schemes included the GE/EPRI method, the reference stress method where reference stress is defined based on the plastic limit load and the enhanced reference stress method where the reference stress is defined based on the optimized reference load. Systematic investigations are made not only on the effect of creep-deformation behaviour on C＊ and creep COD, but also on effects of the crack location, the pipe geometry, the crack length and the loading mode. Comparison of the FE results with engineering estimations provides that for idealized power law creep, estimated C＊ and COD rate results from the GE/EPRI method agree best with FE results. For general creep-deformation laws where either primary or tertiary creep is important and thus the GE/EPRI method is hard to apply, on the other hand, the enhanced reference stress method provides more accurate and robust estimations for C* and COD rate than the reference stress method.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1635-1637
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• 2003

송전선의 뇌사고율은 뇌방전 현상, 송전선의 써지 전달 현상, 아킹혼 사이의 섬락 현상 등 다양한 현상이 관련된다. 송전선의 내뢰설계 목표는 이러한 자연현상 및 물리적인 현상이 편차를 포함하고 있다는 것을 인식하고, 가능한 한 정확도가 높은 뇌사고율을 예측을 수행하고 허용 가능한 뇌사고율을 산정하여 송전선로 설계시 반영하는 것이다. 이러한 예측 계산을 위해 한전에서는 EPRI에서 개발한 FLASH 프로그램을 기본으로 사용해 왔으며, 이 예측계산법의 타당성은 예측 사고율과 사고 실적과의 비교에 의해 검토되어야 한다. 한전에서는 과거 10년간의 뇌사고 실적과 FLASH 프로그램으로 계산한 예측 사고율이 차이가 많이 나타나고 있어, FLASH 프로그램의 예측 계산법의 타당성에 의문을 제기하고 있는 상황이다. 일본 전력회사들은 뇌사고율을 예측 계산하기 위하여 1988년에 전력중앙연구소에서 개발한 프로그램을 사용하여 왔으며, 최근에 사고 실적과의 비교 및 관련 연구를 수행하여 예측 계산 프로그램에 사용되는 파라메타를 수정 보완한 LORP2000-1을 완성하였다. 본 논문에서는 지리, 기후적으로 한국과 유사한 일본의 자연현상을 반영한 LORP 프로그램의 예측계산법이 한전 송전선로의 뇌사고율 예측 계산에 적용 가능성을 사고 실적과의 비교를 통해 검토하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.7
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• pp.875-881
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• 2013

The failure of a bolted joint owing to stress corrosion cracking (SCC) has been considered one of the most important structural integrity issues in a nuclear power plant. In this study, the failure possibility of bolting, which is used to support the steam generator of a pressurized water reactor, owing to SCC and brittle fracture was evaluated in accordance with guidelines proposed by the Electric Power Research Institute, which are called the Reference Flaw Factor method. For this evaluation, first, detailed finite element stress analyses were conducted to obtain the actual nominal stresses of bolting in which either service loads or bolt preloads were considered. Based on these nominal stresses, the structural integrity of bolting was addressed from the viewpoints of SCC and toughness. In addition, the accuracy of the EPRI Reference Flaw Factor for assessing bolting failure was investigated using finite element fracture mechanics analyses.

• Nuclear industry
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• v.23 no.4 s.242
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• pp.50-65
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• 2003

• NEWSLETTER 전기공업
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• no.99-13 s.230
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• pp.7-28
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• 1999