Les cahiers de l'ASN #03 - 10 years after Fukushima

As early as 2012, ASN instructed EDF* to strengthen the safety margins on its NPPs. Starting from the simple observation that during the accident at the Fukushima NPP, the water and electricity resources needed to cool the fuel were lacking, new equipment was installed so that the nuclear installations could deal with degraded situations and function independently for a period of several days. Safer NPPs, today ... REINFORCING SAFETY IN FRANCE * See glossary page 24 18 NPPs in service are subject to ASN regulation and oversight initially lost can be repaired or the response by the emergency crews organised. The improvements made also facilitate crisis management , thanks to additional human and material resources and reinforcement of the existing resources. Gaining time The improvements made (see the guided tour on pages 10 and 11) reinforce the robustness of the installations to situations involving a total loss of electrical power or a total loss of cooling by river or sea water. They help enable the installation to function independently for several days in the event of an accident , thus gaining time so that the resources ASN wants to go even further... Some of this new equipment installed is designed to withstand natural hazards of extreme intensity. However, it is today connected to parts of the installation for which operation cannot be guaranteed in the face of such hazards. ASN therefore asked EDF* to further reinforce the safety of the NPPs, so that there is a complete “hardened safety core*” of resources capable of withstanding extreme situations. 12 • Les cahiers de l’ASN • March 2021