ASN Report 2017

35 ASN report on the state of nuclear safety and radiation protection in France in 2017 ཛྷ ཛྷ in the field of radiation protection: Nogent-sur-Seine; ཛྷ ཛྷ in the field of environmental protection: Dampierre-en-Burly and Nogent-sur-Seine. Irregularities detected at the Areva NP Creusot Forge plant The anomalies brought to light in the production by Areva NP’s Creusot Forge plant, more specifically carbon segregation problems, led ASN in 2016 to ask the manufacturer to carry out a review of the manufacturing files on the components forged in this plant. These reviews revealed production irregularities concerning inconsistencies, modifications or omissions in the production files and concerning manufacturing parameters or test results. In its resolution 2017-DC-0604 of 15th September 2017 ASN ordered EDF to send it the results of the review of the production files for the components forged by Creusot Forge, for each reactor in service and no later than two months before its scheduled restart following its next refuelling outage. EDF is required to complete its review no later than 31st December 2018. The ASN review of the deviations on the first reactors led to additional justification requests but did not reveal any deviations requiring repair or replacement before restart. In conjunction with this review, ASN is continuing to investigate the irregularity detected on the shell of a steam generator on Fessenheim reactor 2. Following the discovery of this anomaly, ASN suspended the steam generator test certificate on 18th July 2016, the effect of which was to keep this reactor shut down. In July 2017, Areva NP transmitted a file demonstrating the mechanical strength of the component concerned. ASN intends to issue a position statement on this subject in the first half of 2018. These irregularities revealed unacceptable practices at the Creusot Forge plant that are incompatible with the principles underpinning the safety culture. They reveal shortcomings in EDF’s surveillance of its suppliers. Other irregular situations, more specifically concerning repair or modificationwork on equipment installed in the NPPs, were detected in 2017. EDF presented ASNwith an action plan which it has begun to implement. Experience feedback from the Fukushima Daiichi accident EDF deployed temporary or mobile measures to reinforce the management of situations involving a total loss of heat sink or electrical power supplies. The Nuclear Rapid Intervention Force (FARN) has been fully operational since the end of 2015. EDF has also begun to implement a large part of the final measures, more particularly the construction of buildings intended to house the ultimate back-up diesel generator sets. 2017 was marked by continued work to install the equipment of the “hardened safety core”. More specifically, the first performance tests on the ultimate back-up diesel generator sets intended for the 900 MWe reactors were successfully run on the Saint-Laurent-des-Eaux site in May  2017. In 2017, ASN also continued examinations to verify that the hardware changes proposed by EDF will be able to meet the safety targets set. Examination of NPP operating life extensions After its position statement in April  2016 on the orientation of the generic study programme to be carried out in preparation for the fourth periodic safety review of the 900 MWe NPP reactors, ASN continued in 2017 to examine the generic studies related to this review. These more specifically aim to demonstrate the serviceability of the reactor pressure vessels, the attainment of the safety reinforcement goals for the spent fuel pools, the mitigation of the potential consequences of accidents - including accidents with core melt - and improved resistance of the facilities to internal and external hazards. The deployment of most of the modifications to the facilities as a result of this periodic safety review and performed during the fourth ten-yearly outage inspection of the 900 MWe reactors, will run until 2030. The Flamanville 3 EPR reactor ASN is continuing to examine the commissioning authorisation application for the Flamanville EPR transmitted by EDF in March  2015. In 2017, it issued a position statement on the safety case studies, more particularly the safety of fuel storage and handling. InDecember  2015, ASN issued a position statement on the approach adopted by Areva NP to demonstrate the serviceability of the Flamanville EPR reactor pressure vessel closure head and bottom head following the anomaly in the chemical composition of their steel. In 2017, ASN examined the technical file from Areva NP presenting the implementation of the approach. ASN considers that this anomaly is not such as to compromise the commissioning of the reactor pressure vessel, provided that specific checks are carried out during operation, to ensure that no flaws appear. As the feasibility of these checks cannot at present be confirmed for the closure head, ASN considers that the current closure head cannot be used beyond 2024. Evaluation of the manufacture of nuclear pressure equipment During the course of 2017, ASN continued to assess the conformity of the manufacture of the replacement nuclear pressure equipment for the NPPs in service and the Flamanville EPR reactor. ASN and the organisations it approves are reviewing the technical documentation and the monitoring of the on-site assembly operations. In 2017, ASN confirmed the conformity of several equipment items. ASN ensured that all the industrial firms have taken on-board the lessons learned from the carbon segregation anomalies detected in 2016 and the irregularities in the Areva NP Creusot Forge plant. Outlook Operating experience feedback from the NPP reactors reveals that there are still inadequacies in the processes employed by EDF to obtain conformity of the facilities with their design and operating baseline requirements and then maintain this compliance over the long term. In 2018, ASN will reinforce its oversight of the processes used by EDF to ensure that they are actually able to detect and then process all deviations from the design and operating baseline requirements, in good time. Management of the conformity of the facilities in service will be a major focal point of ASN inspections in 2018. In 2018, ASN will continue to check the performance of the file reviews for all the components manufactured in the Significant events and outlook