Experimental Accelerator Driven System (xADS) Neutronic Steady State Characterisation at the BoL. G. Glinatsis

This document describes neutron characteristics and performances, at the Beginning of Life (BoL), of the PDS-xADS core, fuelled by MOX fuel at two different enrichments and cooled by LBE, within the adopted safety constraints following the fundamental requirement to preserve the sub-criticality state of the core in any operating and/or accidental condition. The use of two enrichments allows obtaining differentiated characteristics and performances in the two regions of different enrichment. From the whole core neutron characterization point of view this solution allows also to obtain: fuel (at high enrichment) sufficiently reactive; a good flattening of the neutron fluxes, then of the power; a good index of intrinsic 'burner' capabilities; a good 'answer' to the coolant void effect; good behaviour of other reactivity coefficients.