ASN Report 2017

422 ASN report on the state of nuclear safety and radiation protection in France in 2017 Chapter 15  - Decommissioning of Basic Nuclear Installations ASN considers that the level of safety of the nuclear installations undergoing decommissioning on the Chinon site (Chinon A1, A2 and A3) is satisfactory over the short term. In 2018, ASN will examine the periodic safety reviews of the Chinon A1 and Chinon A2 reactors, for which the conclusions reports were received at the end of 2017. Saint-Laurent-des-Eaux A1 and A2 reactors (BNI 46) Complete decommissioning of the facility, which comprises two reactors whose final shutdown was declared in 1990 and 1992 respectively, was authorised by the Decree of 18th May 2010. The prescriptions regulating the water intakes and effluent discharges are set by ASN resolutions published in 2015. EDF wants to change decommissioning strategy, which would push back the end of decommissioning of the Saint-Laurent- des-Eaux A reactors to beyond 2100. ASN is examining the files submitted by EDF concerning its GCR decommissioning strategy (see point 2.1.1). Pending decommissioning of the pressure vessel of the reactors, other operations are performed outside the pressure vessel or to prepare for its decommissioning. Some worksites presenting a risk of contamination by alpha radionuclides (emptying tanks, characterising sludge, removing the source term from the Saint-Laurent-des-Eaux A2 pool) had been suspended since 2016 following the discovery of confirmed cases of internal contamination of personnel working on these sites. An operating rigour action plan was thus initiated by EDF and presented to ASN, which asked that worker training and monitoring be stepped up. ASN conducted several inspections to check that this risk had been adequately taken into account. Operations on these worksites resumed in 2017. ASN observes improvements in the nuclear safety and radiation protection of these installations in view of the results obtained on the first worksites to have resumed their activity. ASN will ensure that EDF restarts the other worksites with similar diligence and will check implementation of the specified actions in 2018. Lastly, in 2018 ASN will examine the periodic safety reviews of the Saint-Laurent-des-Eaux reactors A1 and A2, for which the conclusions report was received at the end of 2017. 2.1.4 Chooz A reactor The reactor of the Ardennes NPP (BNI 163) was the first pressurised water reactor built in France. It was shut down in 1991. Its decommissioning work foreshadows the future decommissioning of pressurised water reactors, the technology of the French nuclear power reactors currently in operation. In the context of partial decommissioning of the reactor, the Decree of 19th March 1999 authorised the modification of the existing facility to convert it into a storage facility – called CNA-D – for its own equipment left on site. Its complete decommissioning was authorised by Decree of 27th September 2007. Decommissioning work on the reactor pressure vessel has been underway since 2016. The licensee must be particularly attentive to the risk of internal contamination by alpha-emitting radionuclides, given the recurrent internal contamination events on the Chooz A decommissioning worksite. With regard to nuclear safety and the environment, ASN considers that the decommissioning operations are being carried out correctly. Lastly, in 2018 ASN will examine the periodic safety review conclusions report for the Chooz A reactor which it received at the end of 2017. 2.1.5 The Superphénix reactor and the Fuel storage facility The Superphénix fast neutron reactor (BNI 91), a 1,200 MWe sodium-cooled industrial prototype is situated at Creys-Malville. It was definitively shut down in 1997. The reactor has been unloaded and the majority of the sodium is neutralised in concrete. Neutralisation of the remaining sodium-potassium eutectic is in progress. Superphénix is associated with another BNI, the APEC fuel storage facility (BNI 141). The APEC essentially comprises a pool containing the fuel unloaded from the reactor pressure vessel and the area for storing the soda concrete packages resulting from the neutralisation of sodium from Superphénix. In 2017, the licensee finished neutralising the reactor pressure vessel and filling it with water prior to the decommissioning of its internal structures. The licensee also continued setting up the cutting and packaging worksites inside the reactor building. The periodic safety review of the two facilities has been carried out. EDF sent the files and conclusions reports to ASN within the prescribed deadlines, namely end of December 2015 for BNI 141 and end of March 2016 for BNI 91. After prior discussions, ASN started the in-depth technical examination of these files in 2017. At the same time, in May 2017 the licensee sent the application file for authorisation to start decommissioning the reactor pressure vessel internal structures, corresponding to the start of the stage 2 of the Superphénix decommissioning decree, which ASN has started examining. ASN considers that the decommissioning operations in 2017 on the whole were conducted with satisfactory safety standards. ASN did however instruct EDF to bolster its organisation for ensuring compliance with commitments and the management of deviations. ASN’s inspections also revealed deficiencies in the monitoring of subcontracted activities, the management of sodium waste and the related risks, and the emergency management organisation. 2.1.6 Irradiated Material Facility The Irradiated Material Facility (AMI), which was declared and commissioned in 1964, is situated on the Chinon nuclear site and operated by EDF. This installation (BNI 94) is not yet undergoing decommissioning even if it has stopped functioning. It was intended essentially for performing examinations and analyses and expert assessments on activated