Nonlinear vibration of the nuclear reactor with clearances in core barrel couplings

This work was supported by the project LO1506 of the Ministry of Education, Youth and Sports of the Czech Republic.The original mathematical model of the VVER-type reactor excited by coolant pressure pulsations was derived as the linear clearance-free model in couplings. Assembly clearances in the key-groove (K-G) couplings between the lower part of core barrel (CB3) and the reactor pressure vessel (PV) (Fig. 1) produce nonlinear vibration of reactor components. Friction vibration interactions in the above mentioned couplings cause the fretting wear on their contact surfaces. The aim of this contribution is an investigation of the VVER 1000 type reactor nonlinear vibration respecting the assembling side clearances and friction in eight K-G couplings uniformly deployed to circumference between CB3 and PV