On the allowed sub-criticality level of lead (-bismuth) cooled ADS: the EU FP6 EFIT and FP7 FASTEF cases

This paper proposes a simple - and at some extent general - methodology to estimate a priori the allowed sub-criticality level in operation of lead (-bismuth) cooled ADSs with steady states neutronic analyses only. The allowed sub-criticality was evaluated for two different ADS concepts, designed within international collaborative projects co-funded by the EURATOM 6th and 7th Framework Programmes (FPs):