Towards more efficient implementations of multiscale thermal-hydraulics

• Reactor-scale system simulations are often affected by complex 3D effects. • To model them, one may couple a subchannel or CFD simulation to the system scale. • This paper discusses a range of coupling algorithms, based on the CEA multiscale modelling experience. • For single-phase, they are stable, simple to implement, and present low numerical overhead. • However, this may not hold for two-phase flows. Candidates for this more challenging...