The development of GEN IV nuclear reactors represents a challenge from an engineering point of view. In particular, the reliability of engineering tools to reproduce the thermal hydraulic behavior of pool-type liquid-metal cooled reactors needs to be demonstrated.
One of the main challenges in numerical simulation is the reliable modeling of heat transfer in liquid-metal cooled reactors by Computational Fluid Dynamics (CFD). Heat transfer applications with low-Prandtl number fluids are often in the transition range between conduction and convection dominated regimes. Compared to common fluids with Pr around one, liquid-metal systems need improved, extended or different physical modeling in CFD. Moreover, most reactor flows involve anisotropic turbulent fluxes and strong buoyancy influences. Here also model improvements are ongoing.
MYRRHA, a flexible fast-spectrum research reactor currently under design in SCK•CEN, cooled by Lead-Bismuth Eutectic (LBE) in pool-type configuration, presents all these issues thus the accurate simulation of the energy transport becomes of paramount importance. The correct simulation of the heat transfer allows establishing the temperature profiles on the structures of the facilities, the heat removal by natural and forced circulation and the presence of stagnant zones and stratification.
To investigate the heat transfer in the MYRRHA reactor and assess the performance of the closure correlations for the turbulent momentum and heat transfer in liquid-metal pool flows, SCK•CEN is currently constructing the E-SCAPE facility (European SCAled Pool Experiment). E-SCAPE is a thermal hydraulic 1/6-scale model of the MYRRHA reactor, with an electrical core of 100 kW as main power source, cooled by LBE.