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Restrained Bending Effect by the Support Plate on the Steam Generator Tube with Circumferential Cracks

원주방향 균열 존재 증기발생기 전열관에 미치는 지지판의 굽힘제한 영향

  • 김현수 (한국전력기술(주) 재료기술그룹) ;
  • 진태은 (한국전력기술(주) 재료기술그룹) ;
  • 김홍덕 (한국전력공사 전력연구원) ;
  • 정한섭 (한국전력공사 전력연구원) ;
  • 장윤석 (성균관대학교 기계공학부) ;
  • 김영진 (성균관대학교 기계공학부)
  • Published : 2007.02.01

Abstract

The steam generator in a nuclear power plant is a large heat exchanger that uses heat from a reactor to generate steam to drive the turbine generator. Rupture of a steam generator tube can result in release of fission products to environment outside. Therefore, an accurate integrity assessment of the steam generator tubes with cracks is of great importance for maintaining the safety of a nuclear power plant. The steam generator tubes are supported at regular intervals by support plates and rotations of the tubes are restrained. Although it has been reported that the limit load for a circumferential crack is significantly affected by boundary condition of the tube, existing limit load solutions do not consider the restraining effect of support plate correctly. In addition, there are no limit load solutions for circumferential cracks in U-bend region with the effect of the support plate. This paper provides detailed limit load solutions for circumferential cracks in top of tube sheet and the U-bend regions of the steam generator tube with the actual boundary conditions to simulate the restraining effect of the support plate. Such solutions are developed based on three dimensional finite element analyses. The resulting limit load solutions are given in a polynomial form, and thus can be simply used in practical integrity assessment of the steam generator tubes.

Keywords

Restrained Bending;Support Plate;Limit Load;Through-Wall Crack

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