Verifica e validazione preliminare sull’accoppiamento del codice di calcolo RELAP5/Mod.3.3 e il codice di fluidodinamica computazionale ANSYS Fluent

The aim of the present work, carried out at DICI of University of Pisa, is to contribute to the development and improvement of coupling methods between CFD codes and thermal-hydraulic system (STH) codes. The CFD solvers adopted are STAR-CCM+ and Fluent, whereas the system code RELAP5 is used. The work was structured in two parts. The first part aims at simulating with STAR-CCM+ the Protected Loss Of Heat Sink with Loss Of Flow accidental scenario inside CIRCE pool type facility with DHR. The second part deals with the development of a “two way” implicit coupling scheme between Fluent and RELAP5 in order to simulate a CIRCE experimental test representative of an isothermal gas enhanced circulation test. The performed simulations are the first application of the in-house developed coupling tool for a pool type facility, showing the opportunity to determinate a new data exchange methodology in order to guarantee a proper convergence. The obtained results shows good agreement with the experimental data giving confidence on the developed tool.