A review for identification and selection of initiating events important for Level 1 probabilistic safety assessment study for a 10 MW water water research reactor (VVR)

A key element in the safety of any Nuclear Research Reactor design is the evaluation of the reactor's ability to withstand events that could reasonably be postulated to occur and, if unmitigated, could lead to core damage or radionuclides releases to the atmosphere. A first step to ensuring that the reactor design is sufficiently robust to withstand accidents is to identify a comprehensive list of IEs that might lead to core damage or radionuclide releases. This work seeks to present as comprehensive as possible the results obtained from identifying possible important initiating events (IEs) applied in the development of PSA Level-1 study for a 10 MW Water-Water Research Reactor (VVR). The methodology involves the listing approach and the IE screening and grouping methodologies and the focus was on internal IEs due to random failures of components and human errors with full power operational conditions and the reactor core was the radioactivity source. The results provided a set of IEs that were as systematic and as representative as possible, providing confidence to the completeness of PSA study. This study is one of the first few to address comprehensive steps to identify important IEs used in Level-1 PSA study.