Challenges Associated with the Mitigation of Unprotected Loss of Flow in Sodium-Cooled Fast Reactor Cores

Abstract : Reactivity effects associated with the mitigation of unprotected loss of flow in sodium fast reactors are being studied to find ways to reduce the potential release of mechanical energy. The studies performed with ERANOS illustrate the importance of cladding removal as well as radial leakage changes during the core slumpdown. Possible arrangements and dispositions are envisioned that would avoid recriticality and hence the possibility of going into severe power excursions. Challenges to be faced by safety studies that would ascertain that no cliff-edge effects occur are then listed.