Integrated Deterministic And Probabilistic Safety Analysis Of AP1000 Passive Containment Cooling System

Risk assessment and safety analysis for passive systems is conventionally performed by a Deterministic Safety Analysis(DSA)of a limited set of Design Basis Accidents under highly conservative assumptions on the system dynamics and physical models.It is limited in the consideration of relevant system parameters,their uncertainty and sensitivity.Probabilistic Safety Assessment(PSA)overcomes the limitations by extending the input parameter set through wide range of probable values,which can be important especially when the system parameter uncertainty significantly influences the system failure behavior.The IDPSA method acts as bridge between deterministic and probabilistic safety analysis,resulting in more reliable values of failure criteria variables corresponding to the design parameters effecting system performance.To demonstrate the applicability of the methodology,performance of the AP1000 passive containment cooling system is studied under accident condition and IDPSA methodology is applied for analysis.The IDPSA methodology scheme starts from determination of the relevant system parameters and failure criteria.IDPSA integrates probabilistic sampling of the uncertainties in the model to the computation of the system response under a design basis accident by a mechanistic T-H code.This demonstrates the potential use and applicability of the method to help in the assessment of required design modifications for other systems.