ASN Report 2017

419 ASN report on the state of nuclear safety and radiation protection in France in 2017 Chapter 15  - Decommissioning of Basic Nuclear Installations Brennilis (EDF) BNI 162 - EL4-D La Hague (Areva NC) BNI 33 - Spent fuel reprocessing plant (UP2) BNI 38 - STE2 BNI 47 - ÉLAN IIB La Hague BNI 80 - HAO Cadarache (CEA) BNI 25 - Rapsodie BNI 32 - ATPu BNI 37B - Effluent Treatment Station (STE) BNI 42 - ÉOLE BNI 52 - ATUE BNI 53 - MCMF BNI 54 - LPC BNI 56 - Radioactive waste interim storage area BNI 92 - Phébus BNI 95 - Minerve Chinon (EDF) BNI 94 - Irradiated Materials Facility (AMI) BNI 133 - Chinon A1D BNI 153 - Chinon A2D BNI 161 - Chinon A3D Fontenay-aux-Roses (CEA) BNI 165 - Procédé BNI 166 - Support Saclay (CEA) BNI 18 - Ulysse BNI 40 - Osiris * BNI 49 - High-Activity Laboratory (LHA) Saint-Laurent-des-Eaux (EDF) BNI 46 - Saint-Laurent-des-Eaux A1 et A2 Marcoule (CEA) BNI 71 - Phénix Chooz (EDF) BNI 163 - Chooz A Tricastin (Areva NC) BNI 105 - Comurhex Tricastin (Eurodif Production) BNI 93 - Eurodif Bugey (EDF) BNI 45 - Bugey 1 Creys-Malville (EDF) BNI 91 - Superphénix Veurey-Voroize (SICN, Subsidiary of Areva) BNI 65 et 90 SICN Grenoble (CEA) BNI 36  : STED BNI 79  : Decay interim storage facility INSTALLATIONS definitively shut down or in the process of decommissioning as at 31st December 2017 * The CEA shut down the Osiris reactor in December 2015 (see chapter 14). FUNDAMENTALS Technical difficulties associated with the decommissioning of the Gas-Cooled Reactors (GCR) The EDF GCRs, which have been shut down for several decades, were designed and built in accordance with the safety requirements of the time. They were not built to function over a very long time scale. Nowadays, the most significant safety issues concern: ཛྷ ཛྷ the behaviour of the reactor pressure vessels in the event of an earthquake; ཛྷ ཛྷ the resistance of the internal structures that support the graphite bricks of the “integrated” reactors, in normal and earthquake situations. Several factors can effectively call into question the resistance of the reactor, such as the ageing of materials (anti-seismic pads) or the corrosion of steel structures. The behaviour of EDF’s gas-cooled reactors had been considered acceptable from an immediate dismantling viewpoint, which might not be the case with deferred dismantling. In 2017, EDF submitted the files to justify the change of strategy proposed in 2016 and to make safe the reactors whose decommissioning is deferred. The reasons put forward by EDF for its change of strategy concern difficulties in maintaining the leak-tightness of the reactor pressure vessel when decommissioning under water, and in treating large quantities of effluents. The improvements in remotely-operated handling equipment mean that it is now possible to carry out dismantling “in air” from a distance, reducing the radiation protection problems. The lack of a disposal route for the low-level long-lived graphite waste from the GCRs is a problem. The first file sent to ASN in March 2017 put these difficulties into the balance for the change of strategy. A second file was sent to ASN at the end of 2017 to demonstrate that it is possible to make these reactors safe for long periods of time. These two files will undergo an in-depth technical examination in 2018 and ASN will adopt a position on the matter as of 2019.