This report is the third in a series of the WGOE (Working Group on Operating Experience) of reports on recurring events. The first two reports NEA/CSNI/R(1999)19 and NEA/CSNI/R(2003)13 discussed a variety of recurring events extracted from more than two decades of international operating experience exchange. In addition to this, the WGOE has issued a consolidated Technical Opinion paper (CSNI Technical Opinion Paper - No. 3, Recurring Events) that summarizes the essence of both of the first two reports for in a brief form.
On the basis of the first two reports the WGOE decided to study in more detail the various sorts of corrective actions associated with recurring events. The aim was to learn about effective corrective actions to prevent from them or to mitigate their consequences. Several recurring events were evaluated against specified selection criteria, and on this basis it was decided to study in detail the PWR event Loss of Residual Heat Removal (RHR) While at Mid-Loop conditions.