Investigation of hydraulic performance and internal flow in a lead-bismuth coolant pump for nuclear reactors

The lead-cooled fast reactor (LFR) is a representative design of Generation IV nuclear reactors. To investigate the flow field characteristics of LFR coolant within an axial-flow pump, computational fluid dynamics (CFD) simulations were conducted for both lead-bismuth eutectic (LBE) and water under five distinct flow rates. Results indicate that LBE consistently exhibits significantly higher head and efficiency than water at all operating points. While the theoretical head difference between LBE and water is minimal, hydraulic losses within the impeller and guide vanes are markedly lower for LBE. The variation trends of skin friction coefficients are similar for both media, yet LBE demonstrates substantially lower coefficients on blade surfaces. The vorticity and turbulent kinetic energy (TKE) in the impeller and guide vanes exhibit a strong positive correlation. In the blade wake region, areas of high vorticity show significant overlap with zones of elevated TKE. The distribution characteristics of both TKE and vorticity remain consistent across the two media, with water demonstrating slightly higher values than LBE.