Post-Fukushima lessons and safety orientations for ASTRID

The Fukushima accident occurred quite simultaneously with the launching of ASTRID preconceptual design phase (March 2011). Thus the workprogram has been able to take into account the main lessons from the Fukushima accident at the very early stages of ASTRID project. The paper presents the main lessons retained from the Fukushima accident, and the safety orientations deduced for ASTRID design. The major items are identified with a focus on the consideration of natural hazards, and the post-accidental management. On each item, safety orientations defined for ASTRID are presented. One of the most important orientation concerns the consideration of extreme natural hazards with the objective to increase safety margin before cliff-edge effect in terms of radiological releases into the environment. Principles for identifying among the safety provisions a "hardened safety core" of features resistant to extreme natural hazards are described. In this context, favorable intrinsic behavior of the concept is underlined. (author)