Analysis and assessment of the risk of accidents of a structure as a system by the method of "Fault Tree Analysis" on the example of a nuclear power facility under seismic impact

The article discusses a method for analyzing the risk assessment of failures of the structure as a system by developing a "Fault Tree Analysis". Formulas were proposed for the numerical estimation of the probability of system failure, taking into account the stochastic dependence of the failures of its elements. On the example of a nuclear power facility, a "wet" stand-alone storage facility for spent nuclear fuel, an analysis of possible scenarios of a facility failure was carried out, a "Fault Tree Analysis" was developed and calculated under seismic impact. It has been determined that the risk of structure as a system under seismic impact is determined by the risk of falling process equipment and building structures on the overlap of storage compartments or stored nuclear fuel. To increase the safety of building structures under seismic impact, it is necessary to pay special attention to the design features of the frame part and the interface between the monolithic storage compartment and the frame part, as the most vulnerable link.