2007:37 Identification of Common Cause Initiating Events Using the NEA IRS Database

The study carried out within the framework of this project is a continuation of work conducted for SKI in 1998 on the identification of Common Cause Initiators based on operational events documented in the NEA Incident Reporting System (IRS). This project covered the events reported in the IRS database with the incident date in the period of 1980- 01-01 – 2006-11-15.

The events of highest concern in nuclear power plants today are the dependent events, where a single event or a single cause initiate a disturbance with impact across redundant systems and, indeed, throughout a plant. Several such events have been observed in the past, often related with support systems, electrical systems, etc.