ASN Report 2017

372 ASN report on the state of nuclear safety and radiation protection in France in 2017 Chapter 12  - EDF Nuclear Power Plants Oversight of NPE manufacturing for the Flamanville 3 reactor During the course of 2017, ASN continued to assess the conformity of manufacture of the Nuclear Pressure Equipment (NPE) for the main primary and secondary systems. Manufacture of the largest equipment items has been completed and is continuing for certain control, stop and check valves. ASN and the approved organisations review the technical documentation and the monitoring of the assembly of NPE carried out on the site. 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) or Olkiluoto (Finland). ASN asks Areva NP 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. 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 3 reactor. In 2017, ASN carried out two inspections of Areva NP concerning the assembly of the NSSS and the preparation of the hydrotests and two 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 2017 (see point 2.2.2). Finally, ASN was informed by EDF in 2017 of deviations during welding of main secondary system piping. Some requirements specific to the break preclusion approach for these pipes were not specified to the subcontractors and were therefore not taken into account at manufacturing or installation of the pipes concerned. These deviations are being examined by ASN and this will continue in 2018. Certification of compliance for Flamanville 3 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, ASN issued the first certificates, concerning four control valves for the Atmospheric Steam Dump Valves (VDA). The compliance evaluation of each of the 200 other NPE or level N1 nuclear assemblies will continue in 2018. 2.11.3 Evaluation of construction, start-up tests and preparation for operation of the Flamanville 3 reactor In its construction site oversight activities, ASN devoted particular attention to the following subjects in 2017: ཛྷ ཛྷ the continued mechanical assembly of the installation led EDF to notify two significant safety events relating to the assembly of the main secondary systems. In 2017, ASN paid close attention to identifying the root causes of these events, evaluating their impact on the safety case and the performance of appropriate remedial, corrective and preventive measures. The investigation of one of these events will continue in 2018. ASN also maintains its oversight of EDF monitoring of the outside contractors and in particular ensures that there is adequate management of deviations detected during these operations; ཛྷ ཛྷ the preparation for and performance of the start-up tests for the various systems of the installation and the satisfactory EDF organisation for management of the overall tests. ASN more particularly reinforces its monitoring of these tests, which require appropriate documentation. The start-up tests must help demonstrate that the reactor’s structures, systems and components meet the requirements assigned to them; ཛྷ ཛྷ the preparation for operation of the Flamanville EPR by the EDF entity which will be responsible for it after start-up. This entity currently comprises more than 400 staff. With a view to reactor commissioning, EDF is continuing with a process of gradual transfer of responsibility for the operation of the structures, systems and components from the entity in charge of reactor construction and start-up operations to the entity in charge of its future operation. The steps in this process enable future operating personnel to upgrade their skills, familiarise themselves with the reactor equipment, draw up operating documentation and develop the appropriate tools. Through its oversight, ASN verifies that the future operating staff take advantage of operating experience and best practices employed in EDF’s NPPs and that they correctly assimilate the working of the equipment during reactor construction and systems start-up tests. ASN also ensures that these preparations for operation are completed before actual commissioning of the reactor; ཛྷ ཛྷ maintaining a strategy to conserve the equipment and structures present on the construction site until the commissioning of the Flamanville 3 reactor. Owing to the reactor commissioning postponements announced by EDF and following the deviations encountered during the conservation of new heat exchangers, ASN ensures that EDF continues to focus particular attention on defining and complying with the requirements associated with the conservation of equipment already installed and the structures built, notably taking account of the impact of filling the systems with water for hydro-testing and start-up tests; ཛྷ ཛྷ appropriate management of environmental protection by EDF, notably the management of the buried waste discovered on the site and the underground water intake structures, plus monitoring by EDF of outside contractors on this topic; ཛྷ ཛྷ radiation protection of workers, given the large number of radiographic inspections performed on the construction site. Generally speaking, these inspections showed that there was room for improvement in the organisation put into place for performance of these activities. In 2018, ASN will pursue its inspections on these topics, in particular preparation for operation. 2.11.4 Cooperation with foreign nuclear safety regulators To be able to share experience feedback, ASN multiplies technical exchanges with its foreign counterparts on the topic of regulating the design, construction and operation of new reactors.