ASN Report 2017

337 ASN report on the state of nuclear safety and radiation protection in France in 2017 Chapter 12  - EDF Nuclear Power Plants 2.1.2 Evaluation of the condition of the fuel and its management in the reactor ASN considers that in 2017 the condition of the first containment barrier, which is the fuel cladding, is on the whole satisfactory. On all the NPP sites, management of this point is considered to be satisfactory or could be improved with regard to a small number of aspects. However, ASN still observes the presence of foreign material in the primary system. The organisation implemented to avoid fuel damage through the ingress of foreign material into the primary system could be improved despite the progress made since 2016. In 2017, the number of significant events linked to fuel handling remains small and ASN observes a good level of involvement by the departments concerned. However, for 2017, ASN notes the following events: ཛྷ ཛྷ recurring malfunctions in the “flux” In-core Instrumentation System (RIC) on Civaux NPP reactor 2, which are the subject of particular attention on the part of ASN; ཛྷ ཛྷ the recurrence of leaking assemblies in the two Civaux reactors, as well as the detection of leaking fuel rods in certain reactors at Gravelines, Cattenom and Nogent-sur-Seine; ཛྷ ཛྷ position defects by certain absorber rod clusters (Le Blayais and Golfech reactors). Finally, in 2017, ASN observed recurring cases of absorber rod clusters blocking when actuated (Saint-Alban/Saint-Maurice and Belleville-sur-Loire reactors). These blockages led ASN to impose operating restrictions or prohibit the restart of these reactors. Investigations are in progress to define the origin of these blockages. 2.2 Nuclear pressure equipment 2.2.1 Monitoring of the design and manufacturing conformity of Nuclear Pressure Equipment (NPE) ASN assesses the compliance with regulatory requirements of the NPE the most important in terms of safety, said to be “level N1”, which are the reactor pressure vessel, the steam generators, the pressuriser, the reactor coolant pumps, the piping and the control valves and relief valves. These regulatory requirements are a guarantee of their safety. They are defined by a European Directive on Pressure Equipment and supplemented by requirements specific to NPE. This conformity assessment concerns the equipment intended for the new nuclear facilities (more than 200 items are concerned on the Flamanville EPR) and the equipment spares intended for nuclear facilities already in operation (replacement steam generators in particular). For the performance of these duties, ASN can rely on the organisations that it approves, which can be tasked by ASN with performing some of the inspections on the level N1 equipment. They are also responsible for assessing conformity with the regulatory requirements applicable to NPE that is less important for safety, referred to as “level N2 or N3”. Oversight by ASN and its approved organisations comes into play at different stages of design and manufacture of nuclear pressure equipment. It takes the form of examination of the technical documentation for each item of equipment and of inspections in the manufacturers’ facilities as well as in those of their suppliers and subcontractors. Five inspection organisations or bodies are currently approved by ASN to assess ESPN conformity: Apave SA, Asap, Bureau Veritas Exploitation, Vinçotte International and the EDF users inspection entity. FOCUS Analysis of the irregularities detected in the manufacturing files at the Creusot Forge plant for components installed in reactors in service Following the detection of irregularities in certain manufacturing files at the Areva NP Creusot Forge plant in 2016, ASN resolution 2017-DC-0604 of 15th September 2017 ordered EDF to send ASN the review report of the manufacturing files for the components forged by the Creusot Forge plant for each reactor in service and no later than two months prior to restart following its next refuelling outage. EDF is required to complete its review no later than 31st December 2018. To date, the ASN examination of deviations on 12 reactors has led to requests for additional justifications and has not brought to light any deviation requiring immediate repair or replacement prior to restart. Subsequent requests could be made for representative checks or tests to clarify the justifications provided. This examination will continue in 2018 for the other reactors. For each reactor, it concerns an average of more than 50 deviations. In conjunction with this review, ASN is continuing to investigate the irregularity detected on the lower 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. In conjunction with its technical support organisation, IRSN, ASN is examining this information which was presented on 27th February 2018 to the Advisory Committee for Nuclear Pressure Equipment (GPESPN). ASN intends to issue a position statement in the first half of 2018.