Mathematical modelling of friction-vibration interactions of nuclear fuel rods

Anotace: Nuclear fuel rods (FRs) are transverselly linked to each other by three spacer grid cells at several vertical levels inside a fuel assembly (FA). Vibration of FA components, caused by the motion of FA support plates in the reactor core, generates variable contact forces between FRs and spacer grid cells. Friction effects in contact surfaces have an influence on the expected lifetime period of nuclear FA in terms of FR cladding fretting wear. This paper introduces an original approach to mathematical modelling and simulation analysis of FR nonlinear vibrations and fretting wear taking into consideration friction forces at all levels of spacer grids.