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

This document describes neutron characteristics and performances at the End of Life of the PDS-xADS core, fuelled by MOX fuel at two different enrichments at the Beginning of Life and cooled by LBE, characterised by an average Bum-Up rate of 22.3 MWd/Kg-HM for a fuel cycle length of 930 days at 100% of the nominal power. Observing that choices and design constraints condition the neutron performances of the reactor, using two differentiated enrichments, while it improves some neutron performances it does not turn out to be sufficient to obtain also good performances in terms of Burn-Up rate. Moreover power redistribution, temperature effect 'good answers', negative value of the void effect reactivity coefficient of the whole core are confirmed, and also small Burn-Up rates causes an appreciable 'degradation' of the void effect reactivity worth. Finally, the coolant void effect influences the neutron spectrum characteristics of the core in a considerable way.