Vibrational analysis of nuclear fuel assemblies can be used for calculation of their expected lifetime period in term of abrasion of fuel rod coating. This monograph involves analytical methods for the fuel assembly modelling, calculation of modal values, sensitivity analysis of fuel assembly eigenfrequencies with respect to design and operational parameters and dynamic load calculation caused by spatial motion of the fuel assembly supporting plates in reactor core. The approach to modelling of vibrations is based on the fuel assembly decomposition into subsystems and on modal synthesis...