Reliability of the emergency ac power system at nuclear power plants

This paper contains an evaluation of the onsite ac power system reliability. The approach to determine the onsite system reliability is to gather from the operating nuclear plants detailed data that have not been available to the NRC, to select typical but detailed design features, and to combine the two to determine ac power system reliability for different designs. Fault trees were constructed from the specific designs, and the categorized data will be used to calculate a spectrum of the expected frequency of station blackout