By the resolutions taken on 5 May 2011, the French Nuclear Safety Authority (Autorité de sûreté nucléaire – ASN) has required all operators of relevant basic nuclear installations, including AREVA, the French Alternative Energies and Atomic Energy Commission (Commissariat à l’énergie atomique et aux énergies alternatives – CEA), the French national power utility (Électricité de France – EDF) and the Laue-Langevin Institute (ILL[1]) to submit by 1 June 2011 at the latest, a memorandum describing the methodology they adopted in order to conduct the complementary safety assessment (évaluation complémentaire de la sûreté – ECS) for some of their installations with respect to the nuclear accident that occurred at the Fukushima-Daiichi Nuclear Power Plant (NPP) in Japan, on 11 March 2011.