ASN issues its opinion concerning the methodologies adopted by the operators in order to conduct complementary safety assessments in the light of the nuclear accident that occurred at the Fukushima NPP

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.

After reviewing those memoranda[2], ASN considered that the methodological approaches submitted by the operators were, on the whole, satisfactory, as long as they also submit all additional information they have agreed to provide during the analysis and comply with all ASN requests, dealing mostly with the following:

• the status of the installation;
• hazards, including the assessment of safety margins, the robustness against flood and the integration of a scenario involving both an earthquake and a flood;
• all events generated in the installation by natural hazards and all hazards associated with its industrial environment, and
• the management of severe accidents.

More specifically, ASN has ordered that a review be made of all consequences induced by the rupture of any dyke of the Grand Canal d’Alsace, located close to the Fessenheim Site, of the Donzère Canal located near the Tricastin Site and of the Provence Canal, located in the vicinity of the Cadarache Site.

In addition, ASN feels that the quality of ECSs will depend on the capability of the operators to detail their proposed approach with sufficient comprehensiveness.

The operators shall also submit to ASN no later than 15 September 2011 their first report on those ECS results in the installations to be reviewed in 2011. ASN, together with its technical support organisation, the French Institute for Radiation Protection and Nuclear Safety (Institut de radioprotection et de sûreté nucléaire – IRSN) will analyse those reports before the end of November 2011.

ASN emphasises the fact that ECSs constitute the first step in the multi-year experience-feedback process following the Fukushima accident.

[1] An international research establishment located in Grenoble, Isère District.

[2] Those memoranda were reviewed by the Advisory Group for Nuclear Reactors (Groupe permanent d’experts pour les réacteurs nucléaires – GPR) and the Advisory Group for Laboratories and Plants (Groupe permanent d’experts pour les laboratoires et usines – GPU) on the basis of IRSN’s detailed analysis.