Seismic capacities of existing nuclear power plant structures

The paper presents a discussion of the more important conservatisms and some of the results obtained when this methodology has been applied to various nuclear plants. Results are shown for both BWR and PWR plants, on both rock and soil sites, and for plants and soil sites, and for plants that were designed in the late 1960s to plants that have yet to load fuel. Safe shutdown earthquake design levels of 0.1 g to 0.25 g were used for these plants. Overall median structural factors of safety for the lowest significant seismic failure capacity at each plant ranged from 3.5 to 8.5. The lowest containment-related failure capacity at each plant ranged from 4.6 to 31. The types of failure corresponding to each safety factor are also tabulated. (orig./HP)