Possible Solutions for the Neutronic Design of the two zones EFIT-MgO/Pb Core

This work has been carried out within the framework of the EUROTRANS project - DM1 domain, having the task to deliver a conceptual design for a lead cooled European Transmutator Demonstrator (in a sub-critical reactor) for MA isotopes. The main goal in the Task 1.2.4 (WP 1.2) is the preliminary definition of the core geometrical and power size and the structure of the fuel assembly. Since at the beginning some terms of the problem were not completely clear, three different design approaches have been analysed. A U-free combustible (MOX spent fuel after 30 years' cooling inserted in a MgO matrix) has been chosen evaluating its impact on the core design, the transmutation and safety performances. Each core (300-400 MWth power) has been regulated to achieve the max allowable power density in order to fast the waste incineration. The reactor transmutation capability has been verified with the ERANOS Code by means of burn up calculations without refuelling.