Modelling of the friction-vibration interactions in reactor core barrel couplings

The key-groove couplings between the lower part of core barrel and reactor pressure vessel in the nuclear VVER-type reactor show assembly side clearances. Vibration of reactor components, caused by coolant pressure pulsations generated by main circulation pumps, produces impulse and friction contact forces in the above mentioned couplings. These forces are used for calculation of power and work of friction forces in the slipping contact surfaces between the key and the groove of the particular couplings and for their fretting wear prediction in dependence on the clearance values. The paper presents an original approach to mathematical modelling and simulation analysis of reactor nonlinear vibrations respecting friction-vibration interactions at all the key-groove couplings with clearances. The method is applied to VVER 1000/320 type reactor operated in the nuclear power plant Temelı ́n in the Czech Republic