Abstract
In this paper, the influence of ageing on Probabilistic Safety Assessment (PSA) results is estimated for Advanced Power Reactor APR1400 onsite power system. Models for component ageing failure rate including surveillance test and replacement ageing control are presented for utilization. Time-dependent ageing effect and average ageing effect over plant lifetime or replacement intervals are evaluated. Components are prioritized regarding their influence on the change of system unavailability and relative increase of their unavailability due to ageing.