In the course of the evaluation of the Philippsburg 1 boiling water reactor in the Federal Republic of Germany, carried out for the licensing authorities, the behavior of the reactor internals during a bearing water line accident was analyzed by theoretical calculations. During this accident, the reactor internals are exposed to a short-time negative pressure wave that expands in the water and is rapidly attenuated. The extent of the influence this load has on the operating capability of the components, particularly of the shut-down facilities, is to be analyzed. Linearly elastic dynamic analyses were carried out on the mechanical behavior of the structure on the basis of calculations of the time- and space-dependent pressure distribution on the core shroud and vessel dome. Staggered geometries and attenuation were not taken into consideration. All calculated components were treated as axially symmetric structures. The load is not axially symmetric and is therefore represented as a Fourier series. The results are given in the form of stresses, displacements, and forces as a function of time.