Development of an updated societal-risk goal for nuclear power safety

The safety-goal policy of the U.S. Nuclear Regulatory Commission (NRC) has never included a true societal-risk goal. In particular, safety goals have focused primarily on radiation-related fatalities, while experience with actual nuclear accidents has shown that societal disruption can be significant even in accidents that yield only small numbers of fatalities. We have evaluated the social disruption from severe reactor accidents as a basis to develop a societal-risk goal for nuclear plants, focusing on population relocation. Our analysis considers several different accident scenarios at five nuclear-plant sites in the U.S. The corresponding source terms were used as input to calculate offsite consequences using actual weather data for each of the five plant sites over a two-year period. The resulting plumes were then compared to population data to determine the population that would need to be relocated to meet current protective-action guidelines. Our results suggest that the number of people relocated is a good proxy for societal disruption, and relatively straightforward to calculate. Safety goals taking into account societal disruption could in principle be applied to the current generation of nuclear plants, but could also be useful in evaluating and siting new technologies.