ASN Report 2018

The third periodic safety review In early 2015, ASN issued a position statement on the generic aspects of the continued operation of the 1,300 MWe reactors beyond thirty years of service. ASN considers that the steps taken or being envisaged by EDF to assess the condition of its 1,300 MWe reactors and control their ageing up until the fourth periodic safety review are acceptable. ASN also considers that the modifications identified by EDF during this study phase will help to significantly improve the safety of these installations. These improvements in particular concern reinforcing protection of the facilities against hazards, reducing releases of radioactive substances in the event of an accident, with or without core melt, and preventing the risk of uncovering of the fuel assemblies stored in the spent fuel pit or during handling. Further to the conclusions of the generic phase of this review, ASN intends to issue additional generic binding requirements in 2019 applicable to all the 1,300 MWe reactors, with the aim of reinforcing their safety. Flamanville NPP reactor 1, the reactors of the Saint-Alban/ Saint-Maurice NPP, Paluel NPP reactors 1, 2 and 3 and Cattenom NPP reactors 1 and 2 carried out their third ten- yearly outage inspection between 2015 and 2018. These third ten-yearly outage inspections for the 1,300 MWe reactors will continue until 2024. • 1,450 MWe reactors The first periodic safety review The generic studies and modifications associated with the first periodic safety reviews of the 1,450 MWe reactors were the subject of an ASN position statement in 2012, which in particular requested additional work by EDF to demonstrate the adequacy either of the studies carried out, or of the modifications made to the installations during their first ten- yearly outage inspection, in order to comply in full with the objectives set in the periodic safety review. The first ten-yearly outage inspections took place between 2009 and 2012. Following the additional work performed by EDF, ASN issued a position statement on the continued operation of the two Chooz NPP reactors and the two Civaux NPP reactors. On this occasion, it issued additional binding requirements to reinforce the safety of these reactors, more particularly requiring the processing of a deviation affecting the water reserves of the secondary system and the performance of modifications to improve control of the fuel storage pool drainage, explosion and high outdoor temperature risks. The second periodic safety review In 2011, EDF transmitted its orientation proposals for the generic studies programme for the periodic safety review of the 1,450 MWe reactors. After consulting the GPR in 2012, EDF supplemented its generic studies programme with a number of measures and clarified some of its proposals. In February 2015, ASN ruled on the orientations of the second periodic safety review of the 1,450 MWe reactors. It more specifically considers that the safety objectives to be considered for the second periodic safety review of the 1,450 MWe reactors must be defined in the light of the objectives applicable to the new nuclear power reactors and asked EDF to study the measures liable to comply with this requirement as rapidly as possible, so that they can be implemented as of the second periodic safety review of the 1,450 MWe reactors. The second ten-yearly outage inspections for the 1,450 MWe reactors are scheduled to start in 2019 with the Chooz B2 reactor and will run until 2022. Ageing control With a view to continued operation beyond the fourth periodic safety review of the 900 MWe NPP reactors, EDF intends to reuse the ageing control approach applied since the third periodic safety review of its reactors, while reinforcing its equipment renovation and replacement projects. Ageing control, in particular for irreplaceable items whose integrity is vital for safety (such as the reactor pressure vessel – see point 2.2 – and its containment – see point 2.3), and obsolescence management, are essential for maintaining a satisfactory level of safety. Having considered in 2013 and then in 2016 that the steps taken or planned by EDF – more particularly to identify the various degradation modes for this equipment, implement the corresponding countermeasures and incorporate operating experience feedback – were on the whole satisfactory, ASN, with the support of IRSN, again examined the ageing and obsolescence control approach and in March 2018 obtained the opinions of the GPR and the GPESPN. ASN notes that EDF has taken account of the requests it made in 2013 and 2016. ASN considers that the steps taken or planned to ensure control of the ageing and obsolescence of the structures, systems and components of the 900 MWe reactors and thus contribute to maintaining their compliance beyond their periodic safety review, supplemented by the undertakings made following the examination, are satisfactory. The programmes for equipment qualification for accident conditions are pertinent and enable this qualification to be extended beyond the fourth ten-yearly outage inspection. Steps are still in progress to cover all the equipment concerned. The envisaged exceptional maintenance operations (replacements, repairs or renovations scheduled during or after the fourth ten-yearly outage inspections) are consistent with the ageing assessments. The improvements identified for the processing of obsolescence are such as to guarantee its satisfactory and long-term processing. The programme of additional investigations defined by EDF and the planned procedures for processing the results are considered to be satisfactory. ASN however identified weaknesses in the processing of operating experience feedback, advance planning of the decisions to be taken, the time taken to process certain generic ageing assessment sheets and the assimilation by the NPPs of the demonstration of the suitability for continued operation in the summary dossier specific to each reactor. Finally, a small amount of additional work is required concerning ageing phenomena on several components of the main primary and secondary systems. In addition, the issue of ageing control was the subject of the first Topical Peer Review stipulated by Council Directive 2014/87/Euratom of 8 July 2014 amending Directive 2009/71/Euratom establishing a Community framework for the nuclear safety of nuclear installations. This Directive requires a peer review, every six years, of a technical aspect relating to the nuclear safety of their nuclear facilities. The procedures of this review are defined by ENSREG (European Nuclear Safety Regulators Group) (see chapter 6, point 2.2). ASN report on the state of nuclear safety and radiation protection in France in 2018  309 10 – EDF NUCLEAR POWER PLANTS 10