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Evaluation of Thermal Stratification and Primary Water Environment Effects on Fatigue Life of Austenitic Piping

열성층 및 냉각재 환경이 오스테나이트 배관의 피로수명에 미치는 영향 평가

  • 최신범 (성균관대학교 기계공학부) ;
  • 우승완 (성균관대학교 기계공학부) ;
  • 장윤석 (성균관대학교 기계공학부) ;
  • 최재붕 (성균관대학교 기계공학부) ;
  • 김영진 (성균관대학교 기계공학부) ;
  • 이진호 (한국원자력안전기술원 기계해석실) ;
  • 정해동 (한국원자력안전기술원 기계해석실)
  • Published : 2008.08.01

Abstract

During the last two decades, lots of efforts have been devoted to resolve thermal stratification phenomenon and primary water environment issues. While several effective methods were proposed especially in related to thermally stratified flow analyses and corrosive material resistance experiments, however, lack of details on specific stress and fatigue evaluation make it difficult to quantify structural behaviors. In the present work, effects of the thermal stratification and primary water are numerically examined from a structural integrity point of view. First, a representative austenitic nuclear piping is selected and its stress components at critical locations are calculated in use of four stratified temperature inputs and eight transient conditions. Subsequently, both metal and environmental fatigue usage factors of the piping are determined by manipulating the stress components in accordance with NUREG/CR-5704 as well as ASME B&PV Codes. Key findings from the fatigue evaluation with applicability of pipe and three-dimensional solid finite elements are fully discussed and a recommendation for realistic evaluation is suggested.

Keywords

Environmental Fatigue;Global Stress Analysis;Local Stress Analysis;Metal Fatigue;Thermal Stratification

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