Jarovoj S. Ukrainian NPPs ecological safety level increase based on hard emergencies analysis at Chernobyl NPP and Fuku-shima-1

The dissertational work is devoted to methods of the analysis of ecological safety of nuclear reactors developed based on experience of the severe accident at Fukushima-1. For this purpose scientific substantiations of principal causes and consequences of severe accidents at Fukushima-1 are executed, the analysis of similar extreme effects for safety of NPPs of Ukraine is carried out. Based on emergency events at NPPs of leading world countries analysis results and experience of estimate or-der of NPP radioactive environmental impact a scientific grounding for sequential stages of complex risk analysis of hard emergencies and their ecological consequences was made. For the first time, the method of identification of the full list of initial events and accident sequences for possi-ble severe accidents at NPPs with WWER is developed with using the symptom-informed approach. The categorization of the NPPs for level of hard emergencies risk and ecological hazard was made. Results of this work can be used to develop and review license reports for the analysis of ecological safety of the NPPs of Ukraine by operating and regulatory organizations.