Analysis of SGTF Vertical Sodium Pump Using ARMD

In sodium cooled fast breeder reactors (FBR), centrifugal sodium pumps are widely used to circulate the hot sodium in primary as well as in secondary loops. Performance of this critical component is very important in reactor circuits as it affects the load factor and availability of the plant. Operation of the centrifugal sodium pumps, limiting its vibration is a challenge in view of both safety and economy. Various experimental facilities have been set up at IGCAR for testing of FBR components. Vertical centrifugal sodium pumps are used to circulate hot sodium in these facilities. The pump shaft is supported by hydrostatic bearing (HSB) at the bottom and by tapper roller bearing at the top. As the HSB runs with the close tolerance, rotor dynamic analysis was carried out for ensuring its effectiveness and proper functioning of the pump. The results obtained from the analysis are also verified by conducting experiments. This paper discusses the rotor dynamic analysis carried out on a vertical sodium pump used to circulate sodium in steam generator test facility (SGTF) using the rotor dynamic analysis software. In this pump, shaft is supported at the top by tapper roller bearing and hydrostatic bearing at the bottom. Critical speeds and corresponding mode shapes were obtained in the operating range of the rotor speed. Stability analysis was performed for the rotor-bearing system to get the threshold speed of the rotor. Unbalance response of the pump was also carried out to estimate the amplitude of vibration at the bearing locations and compared with experimental results.