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Derivation of Elastic Stress Concentration Factor Equations for Debris Fretting Flaws in Pressure Tubes of Pressurized Heavy Water Reactors

가압중수로 압력관 이물질 프레팅 결함의 탄성 응력집중계수 수식 도출

  • 김종성 (순천대학교 기계우주항공공학부) ;
  • 오영진 (한국전력기술(주))
  • Received : 2013.09.14
  • Accepted : 2013.12.03
  • Published : 2014.02.01

Abstract

If volumetric flaws such as bearing pad fretting flaws and debris fretting flaws are detected in the pressure tubes of pressurized heavy water reactors during in-service inspection, the initiation of fatigue cracks and delayed hydrogen cracking from the detected volumetric flaws shall be assessed by using elastic stress concentration factors in accordance with CSA N285.8-05. The CSA N285.8-05 presents only an approximate formula based on linear elastic fracture mechanics for the debris fretting flaw. In this study, an engineering formula considering the geometric characteristics of the debris fretting flaw in detail was derived using two-dimensional finite element analysis and Kinectrics, Inc.'s engineering procedure with slight modifications. Comparing the application results obtained using the derived formula with the three-dimensional finite element analysis results, it is found that the results obtained using the derived formula agree well with the results of the finite element analysis.

Keywords

Pressurized Heavy Water Reactor;Pressure Tube;Debris Fretting Flaw;Elastic Stress Concentration Factor;Finite Element Analysis

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