ASN Report 2017

367 ASN report on the state of nuclear safety and radiation protection in France in 2017 Chapter 12  - EDF Nuclear Power Plants This methodology comprises a first generic phase, which aims to determine the extent to which account has been taken of ageing for an identical reactor series. Subsequently, on the occasion of the VD3 on each nuclear power reactor, a summary file specific to the reactor is produced in order to demonstrate management of the ageing of the equipment and the reactor’s ability to continue to operate for the ten- year period following its VD3. With a view towards the possible continued operation of the nuclear power reactors beyond their Fourth Ten-yearly Outage inspections (VD4), EDF intends to continue with such an approach, which will be extended to all systems, structures and components important for managing not only radiological risks, but also conventional ones. 2.10.3 Management of the review process by EDF 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. ASN 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 these nuclear power reactors. As this generic assessment does not take account of any specific individual features, ASN gives an opinion on the ability of each NPP reactor to continue to function, more specifically based on the results of inspections performed during the reactor conformity check during the third ten- yearly outage and on the assessment of the reactor review report submitted by EDF. In 2017, Gravelines reactor 5 incorporated the improvements resulting from the periodic safety review as part of its VD3, raising the number of 900 MWe reactors that had carried out their VD3 to 30 out of a total of 34. In 2017, ASN also sent the Minister responsible for Nuclear Safety its analysis of the review conclusions reports for the Gravelines 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 reactors. The fourth periodic safety review The continued operation of the nuclear power reactors beyond their fourth periodic safety review is of particular importance in a number of respects: ཛྷ ཛྷ The period of forty years of operation corresponds to the initial design hypotheses for a certain number of equipment items, in particular with regard to their ability to function in accident operating conditions (qualification). The studies concerning the conformity of the installations and the management of equipment ageing therefore need to be reviewed to take account of the degradation mechanisms actually observed and the maintenance and replacement strategies adopted by the licensee. ཛྷ ཛྷ The modifications associated with this periodic safety review allow the completion of the integration on the 900 MWe reactors of the modifications prescribed following the stress tests carried out in the wake of the Fukushima Daiichi NPP accident. This concerns the phase 3 work (see point 2.9). ཛྷ ཛྷ Finally, the wish expressed by EDF in 2010 to significantly extend the operating life of the NPP reactors beyond 40 years was examined by ASN. By this time frame, the 900 MWe reactors will be operating alongside EPR or equivalent type reactors which are designed to meet significantly tighter safety standards. Their safety must therefore be reassessed in the light of these new safety requirements, the state of the art nuclear technologies and the operating life targeted by EDF. After familiarising itself with ASN’s requests of June 2013 concerning the orientations of the generic studies programme carried out by EDF in order to extend the operating life of the nuclear power reactors beyond 40 years, EDF drafted and, in October 2013, transmitted its Orientation File (DOR) for the fourth periodic safety review for the 900 MWe reactors. Further to ASN’s requests for additional data in March 2014, EDF updated its file. In April 2015, ASN asked the GPR for its opinion on the orientations of the generic studies being envisaged by EDF on the various topics contained in the orientation file. Following the GPR meeting, EDF completed its generic studies programme in June 2015 with a certain number of measures and clarified a certain number of its proposals. In April  2016, ASN issued a position statement on the orientation of the generic studies programme to be carried out in preparation for the fourth periodic safety reviews on the nuclear power reactors, after consulting the public on the draft requests for additional information to be sent to EDF concerning the studies and verifications to be carried out. ASN is currently examining the generic studies linked to this review. This is in particular the case of the methods for verifying installation compliance and the management of ageing and obsolescence and studies on the safety of the spent fuel pools, mitigation of the consequences of accidents, improved management of accidents with core melt, the ability of the installations to withstand internal and external hazards and the mechanical strength of reactor pressure vessels. The main files will be submitted for the opinion of the GPR or the GPESPN in  2018 and  2019. ASN intends to issue a position statement on the generic studies linked to this review at the end of 2020 after obtaining the GPR’s opinion on the results of the review in 2020. ASN is also taking part in the work initiated by the High Committee for Transparency and Information on Nuclear Security (HCTISN) to propose methods to involve the public in this fourth periodic safety review for the 900 MWe reactors. The first phase of consultation with the public will take place in the second half of 2018.