Study and modular CFD modeling of the ENEA CIRCE ICE experiment.

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. In the first chapter, the study focuses on the most important components of the real CIRCE facility, also illustrating how their geometries have been imported in the CFD simulation environment. In a second phase, the procedures followed to generate the meshes for the CFD model are described. The third chapter of the research accurately analyses the numerical modeling approaches followed in order to simulate the “regime condition” phase of the CIRCE ICE experiment, providing results and validating them by comparison with the experimental data. The last section of the thesis focuses on the analysis of the simulation of the “SCRAM transient” phase of the experiment. The concluding chapter demonstrates the relevance of the present CFD model, its current and future applications, and its contribution to the progress of the research on the CIRCE experiments.