The European Clearinghouse on Operating Experience Feedback (CH) is regularly issuing topical studies (TSs) with the goal to improve regulatory and operational aspects of nuclear power plants (NPPs) safety. These TSs are assessing NPPs events from several sources (U.S., France, Germany, and IAEA/OECD International reporting system, IRS) in order to analyse trends, contributing factors and relevant insights. The number of events related to each TS varies from tens to several hundred per source. The methodology to draft TSs encompasses the assessment; characterisation and analysis of selected events, which leads to define lessons learned and observations.
The aim of this work is to identify and assess common generic contributing factors and findings from different TSs. The work is part of an ongoing task aiming at assessing overall CH production of TSs during ten years, and to summarise the most relevant findings.
The paper presents initial results from comparative assessment of four topical studies, i.e.: 1) leaks and cracks; 2) loss of offsite power; 3) cooling chains; and 4) maintenance. The evidence for robust trend similarity needs further analysis.
An aggregated list of the most important contributing factors provides some new insights. The most important contributing factors (i.e. maintenance, procedures, and organization) are common for several topical studies. The comparison of selected generic insights gives emphasis to the importance of design and analysis.
This assessment could be extended further for trend comparisons and to the number of considered topical studies.