Gas entrainment at the free surface

In a liquid metal reactor primary circuit, some structures in mixing regions, such as the above core structure, the core outlet zone, the IHX outlets, and thermal stratifications zones. 

DYE CORE TO INTAKE. COHERENT SWIRL THROUGHOUT WATER COLUMN 

Knowledge of primary circuit thermal-hydraulic phenomena is necessary for the determination of structural loads. The methodology used to establish thermal stresses is generally based on close links between research on phenomena and an experimental approach using scaled models. Transposition to the reactor is made using similarity rules directly from experimental results, or using calculation codes, after validation on models or in-pile experiments. 

The increased compactness of the next generation of liquid metal reactors is accompanied by greater complexity of the hydraulic and thermal problems, and a need to decrease uncertainties, particularly for gas entrainment phenomena, temperature fluctuations for thermal striping, and modelling of the core outlet area. 

---