Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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Development of a Short-term Failure Assessment of High Density Polyethylene Pipe Welds - Application of the Limit Load Analysis -

고밀도 폴리에틸렌 융착부에 대한 단기간 파손 평가법 개발 - 한계하중 적용 -

  • 류호완 (고려대학교 기계공학부) ;
  • 한재준 (고려대학교 기계공학부) ;
  • 김윤재 (고려대학교 기계공학부) ;
  • 김종성 (순천대학교 기계우주항공공학부) ;
  • 김정현 (한국과학기술원 원자력 및 양자공학과) ;
  • 장창희 (한국과학기술원 원자력 및 양자공학과)
  • Received : 2014.05.16
  • Accepted : 2015.02.23
  • Published : 2015.04.01
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Abstract

In the US, the number of cases of subterranean water contamination from tritium leaking through a damaged buried nuclear power plant pipe continues to increase, and the degradation of the buried metal piping is emerging as a major issue. A pipe blocked from corrosion and/or degradation can lead to loss of cooling capacity in safety-related piping resulting in critical issues related to the safety and integrity of nuclear power plant operation. The ASME Boiler and Pressure Vessel Codes Committee (BPVC) has recently approved Code Case N-755 that describes the requirements for the use of polyethylene (PE) pipe for the construction of Section III, Division 1 Class 3 buried piping systems for service water applications in nuclear power plants. This paper contains tensile and slow crack growth (SCG) test results for high-density polyethylene (HDPE) pipe welds under the environmental conditions of a nuclear power plant. Based on these tests, the fracture surface of the PENT specimen was analyzed, and the fracture mechanisms of each fracture area were determined. Finally, by using 3D finite element analysis, limit loads of HDPE related to premature failure were verified.

최근 미국에서는 가동기간이 오래된 원전 매설배관에서 부식 및 침식에 의해 삼중수소 누설로 지하수가 오염되는 사례가 급증하고 있다. 따라서, 현재 원전 안전등급 매설배관으로 사용되고 있는 금속재료의 배관을 대신해서 부식 및 침식 등의 열화 손상에 대한 저항성이 우수한 고밀도 폴리에틸렌(HDPE) 배관을 ASME Code Class 3 안전계통 배관으로 사용하기 위한 연구가 수행되고 있다. 본 연구에서는 발전소 가동 중 매설배관에 가해질 수 있는 하중과 온도 범위를 바탕으로 HDPE 배관 융착부에 대한 인장 시험과 저속균열성장 (SCG) 시험을 수행하였다. 시험 결과로 얻은 SCG 시험편의 파단면을 분석하여 HDPE 재료의 파손 기구를 파악하였다. 이를 바탕으로 3D 유한요소 해석을 이용하여 균열이 있는 HDPE 재료가 버틸 수 있는 한계하중에 대한 검증을 수행하였다.

Keywords

References

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