ASN Report 2018

The organisations approved for assessment of NPE conformity are authorised by ASN to assist it with the examination of this design documentation. • Oversight of NPE manufacturing for the Flamanville EPR reactor During the course of 2018, ASN continued to assess the conformity of manufacture of the Nuclear Pressure Equipment (NPE) for the main primary and secondary systems, equipment manufacturing having now been completed. ASN and the organisations it approves are reviewing the technical documentation and the monitoring of the on-site NPE assembly operations. The conformity of the equipment intended for the Flamanville EPR is also evaluated in the light of operating experience feedback from the assembly and testing performed on other EPR type reactors such as those of Taishan (China) and Olkiluoto (Finland). ASN asks Framatome to identify and implement the necessary corrective measures based on this operating experience feedback. This is notably the case with the cracks detected on the seating surfaces of certain valves and vibrations detected on the pressuriser expansion line. With the support of the organisations it has duly mandated, ASN is also examining the handling of deviations identified by the review of the manufacturing files for the components forged at the Creusot Forge plant and installed on the Flamanville EPR reactor. In 2018, ASN carried out six inspections of EDF and its manufacturer Framatome concerning the assembly of the NSSS and the preparation of the hydrotests and three inspections of approved inspection organisations or entities mandated by ASN to monitor these activities. In addition, these inspection organisations or entities themselves carried out several thousand inspections in 2018 on all the nuclear pressure equipment of the Flamanville EPR reactor (see point 2.2.2). • Certification of compliance for Flamanville EPR reactor nuclear pressure equipment At the end of the design and manufacturing checks and if they prove to be satisfactory in the light of the regulatory requirements, ASN issues certification of NPE compliance. During the course of 2017 and 2018, ASN issued the very first certificates. The compliance evaluation of the other NPE or level N1 nuclear assemblies will continue in 2019. ASN also authorised the commissioning and operation of the reactor vessel in 2018 (see box). Filling of the reactor building cavity for the functional tests with vessel open Authorisation for commissioning and operation of the Flamanville EPR reactor vessel At the end of 2014, Framatome revealed an anomaly in the chemical composition of the steel used in the Flamanville EPR reactor pressure vessel closure and bottom heads, which could impair its ability to withstand crack propagation. Together with EDF, Framatome initiated a test programme to demonstrate that the mechanical strength of the steel is sufficient in all operating situations, including accident situations. Framatome transmitted its technical conclusions to ASN in December 2016. Based on an assessment of the files transmitted by Framatome and the additional technical data supplied by EDF, carried out by its nuclear pressure equipment department and its technical support organisation, IRSN, on the opinions of its Advisory Committee for Nuclear Pressure Equipment and of the High Council for the Prevention of Technological Risks, and the observations collected by the public consultation, ASN issued its opinion on this anomaly on 10 October 2017. It indicated that, with certain reservations, it considered that this anomaly did not compromise the commissioning of the reactor pressure vessel. As the commissioning and operation of the Flamanville EPR reactor pressure vessel also required ASN authorisation, notably with regard to compliance with other requirements applicable to the vessel as a whole, Framatome submitted an application in this respect on 13 July 2018, which was then supplemented following requests from ASN. ASN examined this application, drawing on the conclusions of its 2017 opinion. It also verified compliance with the technical and regulatory requirements other than those concerning the chemical composition of the steel of the reactor vessel closure and bottom heads. On the basis of the conclusions of this examination, ASN authorised the commissioning and operation of the Flamanville EPR reactor pressure vessel on 9 October 2018, subject to the performance of a test programme to monitor thermal ageing, plus specific inspections during operation of the facility. As the current state of knowledge does not enable the feasibility of these inspections to be confirmed for the vessel closure head, ASN set a service life limit at end of 2024 for the existing vessel closure head. 312  ASN report on the state of nuclear safety and radiation protection in France in 2018 10 – EDF NUCLEAR POWER PLANTS