• Nuclear Engineering and Technology
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• 제51권2호
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• pp.618-625
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• 2019

When newcomer countries consider a nuclear power programme, it is recognized that the most important organizations are the Nuclear Energy Programme Implementing Organization (NEPIO), the regulator, and an operating organization. Concerning the number of construction delays these days, one of the essential organizations is an Authorized Inspection Agency (AIA). According to World Nuclear Industry Status Report, all of the reactors under construction in eight out of the thirteen countries have experienced delays. Globally, the Flamanville 3 project and Sanmen Unit 1 are 6.5 years and 5 years late respectively. One of the major reasons of delay is due to inappropriate manufacturing and inspection on safety class components. The recommendations are made to develop such an organization: (i) find existing inspection organizations in relevant industries, (ii) contract with expatriates who have experience on nuclear inspection, (iii) develop a legislative framework to authorize the inspection organization with enforcement, (iv) include a contract clause in the BIS for developing the AIA, (v) hold training programmes from vendor country, (vi) during manufacturing and construction, domestic AIA shall be involved.

• 비파괴검사학회지
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• 제23권1호
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• pp.38-44
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• 2003

원자력발전소의 안전성등급 기기에 적용되는 비파괴검사는 실제 결함을 실현한 시험편을 사용하여 결함탐지능력을 검증하도록 하는 기량검증이 요구되고 있다. 가동중인 원전에서 발생 가능한 균열으로는 기계적 피로균열, 열 피로균열 및 입계부식균열 등이 있으나 본 연구에서는 기계적 피로균열을 대상으로 하였다. 인장 피로하중을 사용하여 기계적 피로결함을 제조하기 위해서 시험편을 설계하였고 원하는 피로결함 파면의 조도를 얻기 위해서 인가하중의 크기 및 사이클 수를 조절하여 피로결함을 발생시켰다. 발생된 결함에 대한 정확한 크기와 위치에 대한 물리적 정보를 얻은 후에 결함이 설계된 크기와 위치에 존재하도록 기밀용접을 실시하였다. 기밀용접 후 잔여 용접 흠은 가스 텅스텐 아크용접 및 플럭스 코어드 아크용접으로 채워졌다. 최종 완성된 피로결함 시험편을 방사선투과검사 및 초음파탐상검사를 통하여 검사한 결과, 설계된 길이와 깊이로 피로결함이 형성되었음을 확인하였다.

• Nuclear Engineering and Technology
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• 제30권6호
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• pp.592-608
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• 1998

Inspection of RCS flow measurements for the domestic pressurized water reactors has been performed by the Korea Institute of Nuclear Safety (KINS) as one of the authorized periodical inspection activities. The inspection results for the Westinghouse-type plants reveal that 1) the RCS flow instrumentation has been calibrated by using the initial design and commissioning test result, without reflecting the cycle specific reference flow measurements, 2) the loop-to-loop now variation in the actual flow measurement which has not been considered in the safety analysis affects the asymmetric How transient results, and 3) the measured RCS flows in Kori 3 and 4, Yonggwang 1 and 2 do not support the definition of the best estimate RCS flow, approaching the RCS flow limit. In this study, the revealed problems were discussed with review of the design and the RCS flow measurement uncertainty evaluation, and the technical approaches and recommendations for resolving these problems were proposed.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.666-676
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• 2021

This paper presents numerical estimation of burst pressures of axial cracked U-bend tubes, considering the U-bending process analysis. The validity of the FE simulations is confirmed by comparing with published experimental data. From parametric analyses, it is shown that existing EPRI burst pressure estimation equations for straight tubes can be conservatively used to estimate burst pressures of the U-bend tubes. This is due to the increase in yield strength during the U-bending process. The degree of conservatism would decrease with increasing the bend radius and with increasing the crack depth.

• 대한기계학회논문집A
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• 제39권2호
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• pp.187-193
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• 2015

STS310S 는 열전달 능력이 우수하여, 열교환기용 열전달 튜브 재료로서 많이 사용된다. 튜브의 안쪽은 가스와 물의 혼합물이 흐르고, 튜브 바깥은 화염이 흐른다. 이와 같은 환경에서 튜브는 취화하였고, 누설이 발생하였다. 균열은 안쪽에서 바깥으로 전파하여 취성파괴 하였다. 본 연구는 취성파괴의 원인을 실험과 고찰을 통하여 규명하고, 해결 방법을 제안하였다.