European Clearinghouse: Report on Events of the Cooling Chain of Nuclear Power Plants

This summary report presents the main results of an extensive review of operating experience related to deficiencies of the reactor cooling chain. The cooling systems included in the review are the Essential Service Water System (ESWS); the Component Cooling Water System (CCWS) and the Residual Heat Removal System (RHRS). More than 1000 events from the International Reporting System (IRS) database, the United States Nuclear Regulatory Commission (US NRC) licensee event report database and the French and German national databases were analyzed. Root cause analyses carried out allowed identifying Human and Organizational Factors (HOF) to represent a significant share in the spectrum of root causes. This finding is reflected in the long list of lessons learned from the events. Recommendations how to avoid or mitigate similar events in future are included in the report. The lessons learned are presented apart, in the Annex to this Summary Report. All recommendations focus on enhancing nuclear safety whenever it might be affected.JRC.F.5-Nuclear Reactor Safety Assessmen