ASN Report 2020

equipment. This latter must be substantiated to take account of the deviations observed. With regard to the monitoring of NPE manufacturing, the action taken by ASN in 2020 mainly concerned the preparation for and performance of repairs of welds on the main steam letdown lines subject to the break preclusion requirements (see box page 317). ASN also initiated an analysis of the deviations which affected the post-weld heat treatment of the connection welds on the SG and pressuriser components carried out in Framatome’s Saint- Marcel plant. If the design and manufacturing checks prove to be satisfactory in the light of the regulatory requirements, ASN issues certification of NPE compliance. Over the previous years, ASN issued the very first certificates, including that for the reactor pressure vessel. The compliance evaluation of the other NPE or level N1 nuclear assemblies will continue in 2021. 2.11.3 Assessment of construction, start-up tests and preparation for operation of the Flamanville EPR reactor ASN considers that the design of the Flamanville EPR reactor should be able to achieve the ambitious safety objectives set for the third generation reactors. It should also lead to a significant reduction in the probability of core melt and radioactive releases in the event of an accident, by comparison with the second generation reactors. The EPR reactor design in particular includes systems for managing severe accidents and is able to withstand extreme external hazards. This design only required very minor changes to take account of the lessons learned from the accident at the Fukushima Daiichi NPP. However, a number of important technical subjects are still being examined. This is notably the case with the design of the safety valves on the primary system, the general operating rules that will apply as of commissioning and the lessons learned from commissioning of the first EPR reactors abroad. Oversight of construction also regularly brought to light construction quality flaws, which required corrective action and led EDF to conduct additional checks, which are the subject of discussions with ASN. ASN considers that EDF must supplement the programme of additional inspections scheduled as part of the quality review of equipment other than pressure equipment. EDF has carried out most of the tests needed prior to start-up of the installation. The in-depth analysis of the results will verify that the as-built installation complies with the safety case. 2.12  Studies on reactors of the future The EPR 2 reactor In April 2016, EDF asked ASN for its opinion on the safety options for a PWR reactor project called “EPR New Model” (EPR NM), being developed by EDF and Framatome. This project aims to meet the general safety objectives for third- generation reactors. It aims to integrate the lessons learned from the design, construction and commissioning of the EPR reactors at Flamanville 3, Olkiluoto 3, Taishan 1 and 2 and Hinkley-Point C, along with operating experience feedback from existing reactors. In addition, the design of this reactor will 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 the EPR NM with the support of the IRSN, taking account of the recommendations of Guide No. 22 on PWR design. At the request of ASN, the GPR met in January 2018 to examine this dossier. In 2018, EDF sent ASN its decision to upgrade the technical configuration of the EPR NM to a new version, called “EPR 2”. On 16 July 2019, ASN thus published its opinion on the safety options proposed for the EPR NM reactor and its EPR 2 configuration upgrade. 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 are 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. In 2020, EDF provided additional information on these subjects. It is currently being examined. 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 in a factory and delivered to their installation site. A French SMR project involving EDF, Technicatome, the Alternative Energies and Atomic Energy Commission (CEA) and Naval Group is currently at the preliminary design stage. ASN considers that these projects are opportunities to develop reactors with significant nuclear safety improvements. Generation IV reactors Since 2000, in partnership with EDF and Framatome, the CEA has been examining fourth-generation reactors, notably within the “Generation IV” International Forum (GIF). Given that the CEA’s Astrid project has been abandoned, the industrial deployment of Generation IV reactors cannot be envisaged before the end of this century. 318 ASN Report on the state of nuclear safety and radiation protection in France in 2020 10 – THE EDF NUCLEAR POWER PLANTS