Level-3 Probabilistic Safety Analysis VAB-3 as an NPP Safety Enhancement Stage

Questions pertaining to the development of reactors from the standpoint of the evolution of protection and emergency response systems for large radiation accidents, and development of probabilistic safety analysis at different levels are examined. Examples are presented of the calculation of quantitative characteristics of risk in an accident at a model NPP that show the possibility of using VAB-3 to evaluate the scale of countermeasures as a function of the level of intervention, their effectiveness as a function of the time of application and validation of countermeasures for an individual populated point. It is shown that the VAB-3 methodology must be developed in order to increase NPP safety.