Transactions of the Korean Society of Pressure Vessels and Piping (한국압력기기공학회 논문집)

Korean Society of Pressure Vessels and Piping (한국압력기기공학회)
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Leak-Before-Break Assessment Margin Analysis of Improved SA508-Gr.1a Pipe Material

개선된 SA508-Gr.1a 배관재의 파단전누설평가 여유도 분석

  • 김만원 (한국수력원자력(주) 중앙연구원) ;
  • 이요섭 (한국수력원자력(주) 중앙연구원) ;
  • 신인환 (한국수력원자력(주) 중앙연구원) ;
  • 양준석 (한국수력원자력(주) 중앙연구원) ;
  • 김홍덕 (한국수력원자력(주) 중앙연구원)
  • Received : 2020.04.29
  • Accepted : 2020.05.26
  • Published : 2020.06.30
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Abstract

The effect of improving the tensile and J-R fracture toughness properties of SA508 Gr.1a on the LBB margin for the main steam pipe is investigated. The material properties and microstructure images of the existing main steam piping material SA106 Gr.C used in domestic nuclear power plants and the newly selected material SA508 Gr.1a were compared. For each material, LBB margins were calculated and compared through finite element analysis and crack instability evaluation. The LBB margin of the improved SA508 Gr.1a is found to be greatly improved compared to that of the existing SA106 Gr.C and SA508 Gr.1a. This is because of the increased material's strength and J-R fracture toughness compared to the previous materials. In order to analyze the effect of physical property change on the LBB margin, the sensitivity of each LBB margin according to the variation of tensile strength and J-R fracture toughness was analyzed. The effect of the change in tensile strength was found to be greater than that of the change in fracture toughness. Therefore, an increase in strength significantly influenced the improvement of the LBB margin of the improved SA508 Gr.1a.

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References

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