[en] This report addresses the assessment of the Astrid action (industrial prototype of a sodium-cooled fast breeder reactor of fourth generation) which is financed within the framework of the PIA (programme of future investments). This report aims at synthesising the context, the process and the main stakes of the programme, at analysing results and socio-economic impacts of the action with respect to defined objectives, and the efficiency of the use of PIA credits, and at documenting externalities generated by Astrid and its potential improvements. Thus, it proposes an overview of the various challenges and stakes, presents Astrid as an ambitious and technically advanced project (in terms of technical dimensions, of organisation based on partnerships, of use and consequences of expenses), and discusses the various impacts Astrid may have, even beyond the nuclear sector. It outlines that some objectives have been reached, that improvements have been brought to the programme, and that the project has generated many positive externalities