With regard to the deviation affecting three primary system nozzles, EDF proposed installing a retaining collar around each nozzle concerned. In the event of rupture of the nozzle set-in weld, this collar would limit the size of the resulting break. The consequences of this break would then be covered by the reactor’s existing safety studies. ASN considers that the solution proposed by EDF is in principle acceptable. ASN will issue a final ruling on this modification once EDF has provided the required data concerning the demonstration of the effectiveness of the arrangement, the design, manufacturing and operating requirements applicable to the collars and the quality of the set-in welds around which these collars would be installed. Oversight of construction, start-up tests and preparation for operation Oversight of construction also regularly brought to light con– struction quality flaws, which required corrective action and led EDF to conduct additional checks, which are the subject of discussions with ASN within the context of the quality review. In 2021, ASN checked the production of the additional inspections programme and its implementation, through periodic meetings and two on-site inspections. In 2022, EDF should be issuing the results of these actions and draw up the corresponding conclusions. ASN considers that EDF’s equipment conservation strategy is satisfactory, provided that EDF carries out additional maintenance to prevent ageing of the equipment and sets up an equipment inspection programme at the end of the conservation phase, to check the effectiveness of the steps taken and detect any latent defects. In 2019, EDF had carried out most of the installation start-up tests. In June 2020, EDF sent ASN a first version of the results of these tests. These results are updated as and when the remaining tests are performed. ASN has begun examination of this document, in order to verify that the as-built installation complies with the hypotheses contained in the safety case. This examination will continue in 2022. In addition, during its inspections, ASN ensures that EDF has taken sufficient measures to guarantee that the work carried out after the start-up tests does not compromise the results obtained during these tests. In 2021, ASN carried out 14 inspections on the Flamanville site and two inspections in the engineering departments. ASN also carried out labour inspections. The conclusions of these inspections are presented in the Regional Overview in the introduction to this report. 4 // Oversight of the reactor projects The EPR 2 reactor EDF is developing a new reactor, called “EPR 2”. It aims to incorporate the lessons learned from the design, construction and commissioning of the EPR reactors and from operation of existing reactors. As with the EPR reactors, this project aims to meet the general safety objectives for third-generation reactors. In addition, the design of this reactor aims to incorporate all the lessons learned from the Fukushima Daiichi NPP accident. This more specifically entails reinforcing the design against natural hazards and consolidating the independence of the installation and the site in an accident situation (with or without core melt) until such time as the off-site resources can intervene. ASN examined the Safety Options Dossier (DOS) for this reactor project, then called “EPR NM”, with the support of IRSN, taking account of the recommendations of Guide No. 22 on PWR design. On 16 July 2019, ASN then published its opinion on the proposed safety options. ASN considers that the general safety objectives, the safety baseline requirements and the main design options are on the whole satisfactory. ASN’s opinion identifies the subjects to be considered in greater depth prior to submitting a reactor creation authorisation application. Additional justifications were in particular needed on the break preclusion approach for the main primary and secondary piping, the approach for dealing with hazards, fire and explosion in particular, and the design choices for certain safety systems. The justifications required were specified by ASN in a letter sent to EDF in July 2021. Further to ASN’s opinion, EDF changed its break preclusion approach for the main primary and secondary systems piping. EDF intends to make a number of design, manufacturing and organisational changes to enhance safety. These changes will more particularly concern the choice of materials and manufacturing and inspection techniques. Furthermore, even though EDF applies a break preclusion approach, it also intends to add certain devices to mitigate the consequences of any break, such as separating walls, whip-restraint devices and steam evacuation vents. ASN considers that, given the additional measures, using a break preclusion approach for the main lines of the primary and secondary systems of the EPR 2 reactor project is acceptable. This position statement, issued in September 2021, supplements ASN’s 2019 opinion on the safety options for this reactor project. Examination of the break preclusion baseline requirements will continue in 2022. In April 2021, ASN also issued a position statement on the additional information provided by EDF regarding a military aircraft crash. ASN considers that the EDF approach would be able to achieve sufficient safety objectives for the EPR 2 reactor, identical to those of the Flamanville EPR reactor. In February 2021, EDF sent ASN a preliminary version of the safety analysis report for advance examination, were a construction programme for new reactors actually to be launched. A file examination programme was drawn up jointly with IRSN. Finally, Framatome submitted reactor vessel and SG conformity assessment requests to ASN for these two reactors. Procurement of the first components is scheduled for 2022 on the Le Creusot site. Small Modular Reactors Several Small Modular Reactor (SMR) projects are currently being developed around the world. These are reactors with a power of less than 300 MWe, built mainly in a factory. They use a variety of technologies: that of the PWRs or advanced technologies (high-temperature, molten salt, fast neutron, etc. reactors). The characteristics of the SMRs, in particular their low power and compactness, contribute to their safety. ASN considers that the designers should take advantage of these characteristics to propose reactors aiming for more ambitious safety objectives than the existing high-power reactors. 308 ASN Report on the state of nuclear safety and radiation protection in France in 2021 10 – THE EDF NUCLEAR POWER PLANTS
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