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

Korean Society of Pressure Vessels and Piping (한국압력기기공학회)
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Study on Optimal Welding Processes of Half Nozzle Repair on Small Bore Piping Welds in Reactor Coolant System

원자로냉각재계통 소구경 관통관 용접부 부분노즐교체 예방정비를 위한 최적 용접공정에 관한 연구

  • 김영주 (한전KPS(주) (기술연구원)) ;
  • 정광운 (한전KPS(주) 기술연구원 발전기술연구실) ;
  • 최광민 (한전KPS(주) 기술연구원 발전기술연구실) ;
  • 최동철 (한전KPS(주) 기술연구원 발전기술연구실) ;
  • 조상범 (한전KPS(주) 기술연구원 발전기술연구실) ;
  • 조홍석 (한전KPS(주) (기술연구원))
  • Received : 2018.05.09
  • Accepted : 2018.06.15
  • Published : 2018.06.30
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Abstract

The purpose of this study is to develop a Half Nozzle Repair(HNR) process to prevent the leakage from welds on small bore piping in Reactor Coolant System. The Codes & Standards of tempered bead and design requirements of J-Groove welds are reviewed. Automatic machine GTAW welding and machining equipments are developed to perform HNR process. Single pass welding and overlay welding equipments are conducted in order to obtain the optimal temper bead welding process parameters with Alloy 52M filler wire. Coarse grain heat affected zone(CGHAZ) is formed by rapid cooling rate in heat affected zone after welding. Accordingly, a proper temper bead technique is required to reduce CGHAZ in 1-Layer of welds by 2- and 3-Layers. Mock-up tests show that the developed HNR process is possible to meet ASME Code & Standard requirements without any defect.

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References

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