[en] Pressure fields in the vicinity of reactor buildings may be investigated by: 1) linear wave equation; 2) nonlinear or linear equations of motion, in Lagrangian or Eulerian formulation; 3) experiments. These pressure fields include the pressure loading on the surfaces of building structures. A variational approach to simulate complex physical processes such as wave propagation in gaseous media, depressurization of subcooled fluids and dynamic deformation of structures was used to establish the basic concept for the code system SAN (Structural Analysis). Finite element techniques were applied for discretization of solid, fluid and gaseous media. (orig./WL)