The paper demonstrates the effect of an external explosion on the outer reinforced concrete shell of a typical nuclear containment structure. The analysis has been made using appropriate non-linear material models till the ultimate stages. The generation and the propagation of blast wave and its effect on a cylindrical structure are discussed. Parametric studies have also been performed for surface detonations of different amount of blast charges at a distance of 100 m from a nuclear containment shell. Critical distances have been evaluated for different amount of blast charges for nuclear containment shell. (c) 2005 Elsevier B.V. All rights reserved.