ASN Report 2018

None of EDF’s NPPs activated its PUI in 2018. In 2019, ASN will continue to check the application of the provisions of its resolution 2017-DC-0592 of 13 June 2017 concerning the obligations incumbent upon BNI licensees in terms of preparedness for and management of emergency situations and the content of the on-site emergency plan. Work to ensure compliance with the provisions of the resolution is continuing. 2.4.3  –  Monitoring maintenance of the facilities Preventive maintenance is an essential line of defence in maintaining the conformity of a facility with its baseline safety requirements. This is an important topic, checked by ASN during its inspections in the NPPs. In order to improve the reliability of the equipment contributing to safety but also to industrial performance, EDF is optimising its maintenance activities, drawing on other practices in use in conventional industry and by the licensees of NPPs in other countries. Since 2010, EDF has been deploying a new maintenance methodology, called AP-913, developed by the American nuclear licensees. The main interest of this method is to make the equipment more reliable through in-service monitoring, in order to improve preventive maintenance. Deployment of this maintenance methodology is based on implementation of the following six processes: ∙ ∙ identification of critical equipment and definition of the associated maintenance and monitoring programmes; ∙ ∙ definition of equipment monitoring and maintenance requirements; ∙ ∙ equipment and systems performance analysis; ∙ ∙ definition and oversight of corrective measures; ∙ ∙ continuous improvement of baseline requirements and oversight of reliability; ∙ ∙ equipment lifecycle management. After an AP-913 deployment review in mid-2016, EDF aimed to develop its practices in order to guarantee the quality of maintenance work, refocus performance monitoring on the most important equipment and systems and optimise the volume of maintenance operations. 2.4.4  –  Evaluation of maintenance ASN observes that EDF has implemented action plans to reduce the occurrence of maintenance quality defects, but it also observes that too many of these still persist. Some of them could have been avoided by taking greater account of operating experience feedback from other reactors, including on the same site. An insufficiently questioning and proactive attitude in the implementation of appropriate corrective actions is all too often observed in identifying and processing maintenance-related deviations. ASN still observes activity management problems owing to difficulty with the procurement of spares, in particular because spares are unavailable or non-conforming, but the slight improvement trend observed in 2017 was confirmed in 2018. ASN also regularly observes a lack of rigour in technical oversight of interventions and in monitoring of contractors, along with deficiencies in the traceability of and error-reduction in the interventions. The workers still have to deal with constraints linked to work organisation, such as insufficient preparation for certain activities, unplanned scheduling changes and problems with worksite coordination, leading to activity delays or postponements. These difficulties are more particularly encountered with regard to unscheduled activities such as dealing with unexpected events. Management of maintained qualification of equipment for accident conditions should be improved, notably owing to the sites’ incorrect integration of the binding documents into their operational documents, or to their incorrect application. Post-maintenance requalification of equipment is not always able to detect any work that has been incorrectly performed. Consequently, the reactor restart phases are all too often the time when maintenance quality faults are detected, which can lead to a significant extension of these phases. The AP-913 maintenance method (see point 2.4.3) gives the licensee a clearer picture of the condition of its facilities and enables it to ensure more regular maintenance. However, ASN considers that proactive measures must be taken by EDF to reinforce its maintenance processes. EDF must in particular more strictly manage their implementation and allocate the necessary resources. EDF must also ensure that all participants follow the recommended methods for filling out the equipment monitoring indicators, for the preparation, performance and write-up of field inspections and for the traceability of maintenance decisions. Despite this, ASN considers that most sites have successfully been able to organise themselves to carry out large-scale maintenance operations, such as the preparation for and performance of the ten-yearly outage inspections, which constitute a considerable drain on their human resources, notably those with the most experience, owing to the particularly intense maintenance phases. With a view to extending the service life of the reactors, and in the light of the “major overhaul” programme and the lessons learned from the Fukushima Daiichi accident, ASN considers that it is important for EDF to continue the efforts started to resolve the difficulties encountered and improve the effectiveness of its maintenance work. The Independent Safety Organisation (FIS) EDF’s in-house Independent Safety Organisation (FIS) verifies the actions and decisions taken by the departments in charge of operating the installations, from the viewpoint of safety. On each NPP, the FIS comprises safety engineers and auditors, who conduct a daily check on the safety of the reactors. The working of each FIS is checked and evaluated at a national level by the FIS at EDF’s Nuclear Production Division. Finally, the EDF internal inspection services, in particular the general inspector reporting to the Chairman of the EDF group, assisted by a team of inspectors, represents the highest level of independent verification of nuclear safety within the EDF group. ASN report on the state of nuclear safety and radiation protection in France in 2018  287 10 – EDF NUCLEAR POWER PLANTS 10