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

The Korean Society of Mechanical Engineers (대한기계학회)
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Evaluation of Leak Rate Through a Crack with Linearly-Varying Sectional Area

선형적으로 변하는 단면적을 가진 균열에서의 누설률 평가

  • Received : 2016.03.18
  • Accepted : 2016.08.03
  • Published : 2016.09.01
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Abstract

The leak before break (LBB) concept is used in pipe line design for nuclear power plants. For application of the LBB concept, leak rates through cracks should be evaluated accurately. Usually leak late analyses are performed for through-thickness cracks with constant cross-sectional area. However, the cross-sectional area at the inner pipe surface of a crack can be different from that at the outer surface. In this paper, leak rate analyses are performed for the cracks with linearly-varying cross-sectional areas. The effect of varying the cross-sectional area on leak rates was examined. Leak rates were also evaluated for cracks in bi-material pipes. Finally, the effects of crack surface morphology parameters on leak rates were examined.

원자력 배관 설계에는 파단전 누설(leak before break, LBB) 개념이 사용되고 있다. LBB 개념의 적용을 위해서는 관통균열을 통한 누설률을 정확하게 예측할 수 있어야 한다. 단면적이 일정한 관통균열에 대한 누설률 해석은 많이 이루어지고 있으나 실제 관찰되는 관통균열에서는 배관 내면 쪽과 외면 쪽의 단면적이 다른 경우가 많이 발생된다. 따라서 본 논문에서는 유동경로를 따라 선형적으로 변화하는 단면적을 가진 관통균열에 대하여 누설률을 평가하여 단면적의 분포가 누설률에 미치는 영향을 살펴보았다. 또한 클래딩 등에 의하여 두께 방향으로 이중 재료로 된 배관에 존재하는 관통균열에 대해서도 누설률을 평가하여 유동경로를 따라 달라지는 균열면 형태학적 변수가 누설률에 미치는 영향을 살펴보았다.

Keywords

References

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