ASN Report 2018

• Equipment or component obsolescence Before it is installed in the NPPs, some equipment undergoes a qualification process designed to ensure that it is able to perform its functions in the stress and atmosphere conditions corresponding to the accident situations in which it would be required. The availability of spares for this equipment is heavily dependent on changes in the industrial network of suppliers, with the cessation of manufacture of certain components or the closure of the manufacturing company, potentially leading to supply difficulties. Prior to installing these parts, EDF must check that the new spares that are different from the original parts do not compromise the qualification of the equipment on which they are to be installed. Given the length of this procedure, the licensee must anticipate these needs well in advance. • The nuclear power reactors ageing control process The approach adopted by EDF to control the ageing of its facilities is based on three key points: ∙ ∙ Anticipate ageing in the design: in the design and during manufacture of components, the choice of materials and the installation arrangements must be tailored to the intended operating conditions and take into account the kinetics of known or presumed deterioration processes. ∙ ∙ Monitor the actual condition of the facility: during operation, degradation phenomena other than those considered in the design can be discovered. The periodic test and preventive maintenance programmes, the additional investigation programmes as well as examination of operating experience feedback (see points 2.4.3, 2.4.4, 2.4.7, 2.4.8 and 2.6.1) must enable these phenomena to be detected sufficiently early. ∙ ∙ Repair, renovate or replace equipment: given the operating constraints liable to be generated by such routine or exceptional maintenance operations, especially when they can only be performed during NPP reactor outages, EDF must seek to anticipate them, to take account of the time needed to procure new components, the time required to prepare for and carry out the work, the risk of obsolescence of certain components and the loss of technical skills on the part of the workforce. At the request of ASN, EDF established a methodology for controlling the ageing of its nuclear power reactors beyond 30 years of operation, the aim of which is to demonstrate their ability to continue to function until their fourth periodic safety review in satisfactory conditions of safety, on the one hand in the light of the understanding of and ability to control the mechanisms and kinetics of the damage modes linked to ageing and, on the other according to the condition of the facilities observed during their third periodic safety review. This methodology comprises a first generic phase, which aims to determine the extent to which account has been taken of ageing for a group of similar reactors. Subsequently, on the occasion of the third periodic safety review on each nuclear power reactor, a summary file specific to the reactor is produced in order to demonstrate control of the ageing of the equipment and the reactor’s ability to continue to operate for the ten-year period following its third ten-yearly outage inspection. With a view to the possible continued operation of the nuclear power reactors beyond their fourth periodic safety review, EDF intends to continue with such an approach, which will be extended to all systems, structures and components important for controlling not only radiological risks, but also conventional ones. 2.10.3  –  The periodic safety reviews in progress on NPPs • 900 MWe reactors The third periodic safety review In July 2009, ASN adopted a position statement on the generic aspects of the continued operation of the 900 MWe reactors beyond 30 years. ASN did not identify any generic elements compromising EDF’s ability to ensure the safety of the 900 MWe reactors up until the next periodic safety review. It considers that the new baseline safety requirements presented in the generic safety report for the 900 MWe reactors and the modifications to the installation envisaged by EDF are such as to maintain and improve the overall level of safety of its nuclear power reactors. This generic assessment does not take account of any specific individual aspects and ASN gives a ruling on the suitability for continued operation of each nuclear power reactor, notably on the basis of the results of the conformity checks and the assessment made in the periodic safety review conclusion report for the reactor submitted by EDF. In 2018, Gravelines NPP reactor 6 and Cruas-Meysse NPP reactor 2 incorporated the improvements resulting from their periodic safety review as part of their ten-yearly outage inspection, meaning that 32 out of the thirty four 900 MWe reactors have carried out their third periodic safety review. In 2018, ASN also sent the Minister responsible for Nuclear Safety its analysis of the review conclusions reports for the Bugey 3 reactor. On the basis of this analysis, ASN has not identified any element that would compromise EDF’s ability to satisfactorily control the safety of this 900 MWe reactor until the next periodic safety review. Pursuant to Article L.593-19 of the Environment Code, ASN took this opportunity to issue additional requirements designed to reinforce the safety of this reactor. The fourth periodic safety review The fourth periodic safety review for the 900 MWe reactors is dealt with in a specific thematic sheet (see the introduction to this report). • 1,300 MWe reactors The second periodic safety review In 2006, ASN gave a favourable opinion to the generic aspects of continued operation of the 1,300 MWe reactors up to their third periodic safety review, provided that the modifications decided on during this review were effectively implemented. The twenty 1,300 MWe reactors have now all undergone their second periodic safety review and have incorporated the improvements resulting from the review. Pursuant to Article L.593-19 of the Environment Code, ASN in 2014 sent its position statement on the continued operation of the two Saint-Alban reactors, Cattenom reactors 2 and 3, the two Nogent-sur-Seine reactors and Penly reactor 1 and took this opportunity to issue additional requirements designed to reinforce the safety of these nuclear power reactors. It is currently preparing its position regarding the continued operation of the other 1,300 MWe reactors. 308  ASN report on the state of nuclear safety and radiation protection in France in 2018 10 – EDF NUCLEAR POWER PLANTS