Preliminary core design of the European lead-cooled system

GEN-IV reactor concepts have to fulfil four strategic goals, namely: sustainability, economics, safety and reliability, proliferation resistance and physical protection. Fast spectrum nuclear reactors, such as ELSY, enable a much more reduction of uranium consumption, produce significantly less MA compared to thermal spectrum facilities and, in a long term, can burn MA more efficiently. To reduce the operational cost it is important to reduce a number of the intermediate reactor shutdowns for the core reshuffling. Therefore the core composition should be designed with the sufficient reactivity reserve and small reactivity swing to assure at least one year of operation without fuel reloading. The paper presents the specifications of the ELSY-600 MWe (1500 MWth) core design and reports the results of a first round of the nuclear physics, thermal-mechanical and thermal-hydraulic assessments of such a core consisting of closed hexagonal MOX-fuel assemblies. It is shown that with a start-up core based on the present fuel rod design and a 2$-reactivity excess, one can operate during 3.5 years without core reshuffling, reaching a peak burnup of about 60 GWd/tHM. Beyond that period pellet-cladding mechanical interaction occurs, requiring a further fuel design optimisation.