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An Investigation of Turbine Blade Ejection Frequency Considering Common Cause Failure in Nuclear Power Plants

공통원인고장을 고려한 원전 터빈블레이드 비산빈도계산

  • Oh, Ji-Yong (Central Research Institute, Korea Hydro & Nuclear Power Co., Ltd.) ;
  • Chi, Moon-Goo (Central Research Institute, Korea Hydro & Nuclear Power Co., Ltd.) ;
  • Hwang, Seok-Won (Central Research Institute, Korea Hydro & Nuclear Power Co., Ltd.)
  • 오지용 (한국수력원자력 중앙연구원) ;
  • 지문구 (한국수력원자력 중앙연구원) ;
  • 황석원 (한국수력원자력 중앙연구원)
  • Received : 2011.02.21
  • Accepted : 2012.02.08
  • Published : 2012.04.01

Abstract

The objective of this research is to examine the probabilistic approach to evaluating turbine ejection frequency considering common-cause failure. This paper identifies basic turbine ejection mechanisms under high and low speeds and presents a detailed probabilistic methodology (fault tree) for assessing ejection frequency. The alpha factor methodology is applied to common-cause failure evaluations. The frequencies under different test schemes are compared and the propagation of uncertainty through the fault tree model is evaluated. The following conclusions were reached: (1) the turbine blade ejection frequency due to ductile failure under high speed is around 8.005E-7/yr; (2) if common-cause failure is considered, the frequency will be increased by 11% and 33% depending on the test scheme; and (3) if the parameter uncertainties are considered, the frequency is estimated to be in the range of 9.35E-7 to 1.13E 6, with 90% confidence.

Keywords

Turbine;Ejection;Missile;Fault Tree;Uncertainty;Staggered;Non-Staggered

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