Multi-scale coupled simulation of E-SCAPE at isothermal conditions

Liquid metal-cooled reactors are a Generation IV reactor type that has the advantage of high power density owing to the high thermal conductivity of metals. The thermo-hydraulic phenomena that occur in the reactor pool, such as flow patterns, thermal diffusion, and stratification in different scenarios (steady operation, accidents, non-critical transients, etc.) have been and still are a topic of great interest in various research projects. One such reactor is MYRRHA, a flexible fast-spectrum research reactor cooled by lead-bismuth eutectic (LBE) in a pool configuration under design in Belgium. In support of its development, the European Scaled Pool Experiment (E-SCAPE), a 1/6th scale model of the same, was developed within the collaborative European framework of the THINS and MYRTE projects. This LBE mock-up, constructed and operational at SCK CEN in Belgium, serves to provide relevant data that gives insight into the thermo-hydraulic phenomena and provides the possibility to carry out numerical code validation and support the overall design of MYRRHA. In the framework of the collaborative European project PASCAL, NRG aims to perform multi-scale simulations of asymmetric accident scenarios (i.e. Single Loop Heat Exchanger Failure and Single Pump Failure) of E-SCAPE by coupling the in-house System Thermal Hydraulic (STH) code SPECTRA to the commercial Computational Fluid Dynamics (CFD) code STAR-CCM+ via the in-house coupling tool myMUSCLE: MultiphYsics MUltiscale Simulation CoupLing Environment. In a previous article, the construction of the standalone models of SPECTRA and STAR-CCM+ was reported. The simulation results were compared to a steady state isothermal E-SCAPE experiment at a mass flow rate of 93.2 kg/s and a temperature of 180 °C, showing good agreement of both models with each other and the experiment. In this article, the next step is taken by performing coupled calculations of the same isothermal case and comparing to the standalone and experimental results. The calculations reveal stable solutions that are well in agreement with the standalone results