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on 4/4/25 at 9:58 AM
This report presents a study performed on a set of common-cause failure (CCF) events within the International Common-cause failure Data Exchange (ICDE) project. The topic of the study was external factor events. An external factor event is a CCF event or CCF fragility (impairment) related to external or environmental factors or an event directly caused or triggered by such factors (conditions).
The report is mainly intended for designers, operators and regulators to provide insights into the type of external factor events in the ICDE database. The insights can give valuable experience to support and improve the external event modelling in probabilistic risk assessment (PRA) models and provide CCF data for quantification purposes.
The report summarises the results of two data analysis workshops performed by the ICDE steering group, presents CCF defence aspects, and includes in total 64 external factor events spanning an observation period from 1977 through 2015. The data analysis included an assessment of the event parameters: event cause, coupling factor, corrective action, CCF root cause, event severity and detection method.
