Climate changes and influence of extreme external factors on NPP safety

Worldwide in nowadays there are 450 nuclear reactors in operation with total installed capacity of over 370 GWe, in Nuclear Power Plants (NPPs) in 31 states. Their share in the limitation of the greenhouse emissions in the environment is very significant. The relation "global climate changes – natural disasters and other extreme events" is definitely supported by events that took place in the last several decades. From the point of view of NPP safety, there is obvious necessity for re-estimation of the importance and the analysis of the possible extreme external factors, their consideration during the design and operation of NPPs, especially after the severe accident on in"Fukushima" NPP. The presented paper aims two goals: Brief review of the most important external factors for NPPs, and respectively their most significant characteristics; Outlining of the most probable factors, which may cause basic extreme impact on the equipment and systems in NPP, and on external facilities related / interconnected to the NPPs – electrical power lines for HV/EHV, communication systems, power supply facilities, hydro facilities, etc. The results are presented as generalized information for main extreme external factors and systematized analysis of their potential impact on the NPPs.