Damage Probability of Turbine Missile Impact

Abstract

AS part of probabilistic safety analysis, the risk of structural damage to critical components of a nuclear power power plant from accidentally generated turbine missiles has been evaluated. Perforation and scabbing modes of failure are considered for concrete walls, whereas perforation in case of steel barriers is identified as the only mode of failure. Available empirical formulas for assessing local damage are evaluated using turbine missile test data from the U.S. and elsewhere. The most applicable formulas are selected and uncertainties in their predictions are evaluated and incorporated in the assessment of damage probability. Monte Carlo technique and Advanced First Order Second Moment (AFOSM) method are used in evaluating damage probability. Simplified methods derived for the assessment of turbine missile damage probability are compared with Monte Carlo and AFOSM methods, and limitations of the simplified methods are investigated. Evaluation of damage probabilities of multiple barriers are also illustrated. Bounds on damage probabilities are given using normal and chi‐square distributions.