The research illustrated in the present thesis focuses on the study and numerical CFD modeling of the ICE experiment conducted in the CIRCE facility, located at the ENEA research center of Brasimone (Bologna, Italy). Such experiment plays a pivotal role in the research process involving the use of HLM (heavy liquid metals) as coolants in the primary circuit of the future 4th generation LFR reactors. The present study describes the generation process of a “modular” CFD model of the CIRCE ICE experiment (created by means of the Siemens STAR-CCM+ software), with the main aim to investigate and appropriately simulate the fluid-dynamic behaviour of molten lead-bismuth eutectic under the typical circumstances required by a modern LFR reactor.