The impact of americium on the ULOF and UTOP transients of the European Lead-cooled SYstem (ELSY)

The Unprotected Loss-of-Flow (ULOF) transient and the Unprotected Transient-Over-Power (UTOP) have been evaluated for the European Lead-cooled SYstem (ELSY) for americium concentrations in the fuel between 0% and 10%. With americium in the core, the ELSY design exceeds the maximum allowed asymptotic temperature limit for fuel during UTOP, except for low Am contents. During ULOF, fuel and clad temperatures stabilize below the asymptotic temperature limits.

► Reference ELSY design is not suitable for Am burning.
► During ULOF at ELSY with up to 10% Am temperatures stabilize below maximal limits.
► During UTOP fuel temperature exceeds the limits for more than 1.5% Am.