Prestressed concrete containment vessel (PCCV) is the ultimate barrier in a nuclear power plant against radioactivity release during normal accident conditions. In certain PCCVs, steel liners are provided at inner surface to control leakage rate during accident conditions. Qualification of PCCV for air leakage resistance up to its design pressure is done through tests. Estimation of air leakage for beyond design basis accident or severe accident conditions using analytical technique is very complex and computationally challenging. An attempt has been made in this paper to estimate the air leakage rate of a lined containment for severe internal accidental pressure. The strain induced liner damage is coupled with available formulation for air leakage through cracked concrete section to estimate the leakage through lined concrete containment section. In this study, it is assumed that air will leak through cracked concrete but amount of leakage will be controlled by the degree of damage in the co-located liner. The damage of liner is initiated at its critical J-integral value; J_(cr). Leakages are calculated based on different damage propagation patterns, such as linear, parabolic and power variation from initiation of damage to final damage for different J_(cr) values of liner material. Finally a probabilistic study is conducted considering variability of all these parameters and it is observed that the test values are within the zone of mean and 95% confidence curve.
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