Challenges Associated to the Mitigation of ULOF in Sodium-Cooled Fast Reactor Cores

Abstract

The reactivity effects associated to the mitigation of the Unprotected Loss Of Flow (ULOF) in Sodium Fast Reactors are being studied for finding means to reduce the potential release of mechanical energy. The studies performed with ERANOS illustrate the importance of the cladding removal as well as the radial leakage changes during the core slump-down. Possible arrangements and dispositions to be taken to avoid re-criticality and hence the possibility to go into severe power excursions are then envisioned.Challenges to be faced by safety studies to ascertain no cliff edge effects are occurring are then listed.