[en] This paper describes the calculations of probabilistic dynamic responses to seismic forces of a Floating Nuclear Plant (FNP) Platform restrained by mooring struts attached to caissons, within a protective breakwater. An offshore nuclear power plant, similar to the one proposed for the Atlantic Generating Station, is chosen as the example problem. The FNP is modelled using eight-noded isoparametric plane strain elements. The buoyancy effects are accounted for by boundary elements with appropriate axial stiffnesses. The fluid medium is isolated from the structure, and discretized using two-dimensional plane strain eight-noded isoparametric quadrilateral finite elements with pressures as the nodal unknowns. The fluid structure interaction is simulated by incorporating the hydrodynamic forces, associated with frequency-dependent added mass and damping, as external loading at the interfacial nodes of the FNP platform. (orig.)