The impact of americium on transients in the European Lead-cooled SYstem ELSY loaded with nitride fuel

Abstract The Unprotected Loss-of-Flow transient (ULOF) and the Unprotected Transient-Over-Power (UTOP) have been evaluated for a modified design of the European Lead-cooled SYstem (ELSY) using nitride fuel. Additional americium has been added to the core in concentrations of 0%, 4% and 8%. During ULOF, fuel and clad asymptotic temperatures stabilize below limits. For UTOP, however, the maximum allowed cladding temperature limit is exceeded at EOC and introduction of a power penalty is necessary for Am transmutation. The power penalty is higher than that reported for SFR.