[en] The capacity of safety-related structures at nuclear power plants to safely absorb impulsive loadings arising from accidental explosions is estimated. These safety-related reinforced concrete structures and structural components were assumed to meet the regulatory criteria for seismic and tornado loads which are based on allowing only elastic response. Blast waves from the detonation of both solid explosives and fuel-air mixtures were included in the analysis. Since the expected frequency of occurrence of large, nearby explosions is generally very low, and since the forcing function from a blast loading is characterized by a single impulse, allowing only elastic response is very conservative. In this report, dynamic responses for both elastic and elastic-plastic behavior of the most vulnerable structural components were considered. The principal results are presented as the minimum allowable distance versus weight of explosive for plants sited in the various tornado intensity regions in the United States. More detailed results cover blast capacity as a function of the amount of steel reinforcement. 16 references, 19 figures, 37 tables