2D and 3D numerical investigations of sodium boiling in sodium cooled fast reactor with MOX fuel and low sodium void reactivity effect during unprotected loss of flow accidents

Highlights: • Behavior of SFR under ULOF simulated for Low Sodium Void Worth design. • No core melting simulated and stable boiling behavior predicted by both codes. • Different frequencies and amplitudes of boiling regimes with SIMMER and COREMELT. • 3D modeling performed with COREMELT confirms oscillating behavior and absence of core melting. • If confirmed by enough experimental evidence, could make safety demonstration of SFR more robust.