Outcomes of the PELGRIMM project on Am-bearing fuel in pelletized and spherepac forms

The PELGRIMM project was a FP7-European project (funded by the European Commission, Grant Agreement No. 295664), carried out from 2012 to 2017. It was devoted to the investigation of spherepacked and pelletized fuel forms for Minor Actinide transmutation in homogeneous and heterogeneous recycling modes. PELGRIMM aimed at constituting a new step in the long term process in the assessment of Minor Actinide-bearing fuel, initiated within the European projects ACSEPT, F-BRIDGE, CP-ESFR and FAIRFUELS. The present paper provides an overview of the main technical outcomes gained within PELGRIMM. The developments of alternative processes in order to simplify synthesis routes and to limit secondary waste streams for Minor Actinide-bearing fuel preparation are detailed. The first results of behaviour under irradiation of spherepacked and pelletized fuel forms are provided from Post-Irradiation Examinations on (U,Pu,Am)O2 and (U,Am)O2 fuels respectively irradiated during SPHERE and MARIOS experiments, along with the description of the latest irradiation experiment, MARINE. In parallel, the capabilities of existing models and calculation codes have been improved to describe Minor Actinide-bearing fuel behaviour under irradiation in a more reliable way, and their predictive results have been compared to available Post-Irradiation Examinations. Finally, to start linking fuel behaviour with core neutronic problematics, a preliminary design of a Sodium-cooled Fast Reactor core loaded with spherepacked (U,Pu,Am)O2 fuels was built and correlated preliminary safety assessments have been performed.