Insights from level-1 Probabilistic Safety Analysis of Prototype Fast Breeder Reactor

► Estimated CDF of PFBR is ∼0.9E−06/yr. ► Functional reliability analysis is included in event tree. ► Approximate unavailability can be estimated by considering only CCF. This paper presents the results and important insights from level-1 Probabilistic Safety Analysis of Prototype Fast Breeder Reactor (PFBR) which is under construction at Kalpakkam. Level-1 PSA of PFBR was carried out as per the regulatory requirement in India. The desired target value for overall Core Damage Frequency (CDF) of PFBR is ≤1E−6/reactor year (ry). The scope of this study is limited to internal events at full power. The salient feature of this study is the inclusion of functional failure of natural convection based decay Heat Removal System in event tree development. As in most of the safety systems the unavailability contribution is dominated by CCF events and hence are highly sensitive to CCF model parameters. The dominant contributors to Core Damage Frequency are Loss of Off-Site Power and Loss of Steam Water System. Research & Development (R&D) input is required in modeling flow blockage events which has the largest uncertainty.