Assessing the Impact of Common Cause Failures on Site Risk within Level 1 Multi-Unit PSA

Common cause failures (CCFs) may lead to the simultaneous unavailability or failure of numerous components in nuclear power plant because existence a shared when an initiating event disrupts normal functioning plants. The presence common (intra-unit and inter-unit) can be recognized multi-unit probabilistic safety assessment (MUPSA) as crucial dependency factor that influence accident scenarios core damage frequency (CDF), CCF affect availability proper operation mitigating systems. Since such are likely significantly undermine benefits concept redundancy systems, it is necessary identify CCFs contribute site analyse their overall quantitative magnitude qualitative proportions. In this study, twin-unit generic pressurized water reactor (PWR) modeled using AIMS-PSA software. For loss-of-offsite-power (LOOP) station blackout (SBO) events, CDF was calculated, cut-sets produced by quantification were examined for basic events fault trees. contributions examined. trees contributed 4.58% combined LOOP followed SBO event. alone leads damage, while 17.19% damage. With considered modeling process, estimated with increased 7.53% inclusion 7.42%. A 15.66% increase recorded compared without events. results show how contribution CDF. at impacted considered. various fundamental compositions percentage explicitly minimal which units. conclusion, study’s findings help us better understand risk also act starting point future studies on categorizations effects within MUPSA.