- 102 - The main nonconformities detected during processing concern: locking the threaded fasteners of certain valves, cracking of electrical relays or their sockets, default fixings of certain Printed Circuit Board (PCB), sensor qualification faults, excess lubricant on the contacts of certain relays, strength defects of lines, exchangers, catwalks or access towers. All these nonconformities are not simultaneously present on all the reactors. Similarly, two design anomalies are being processed: Sufficiency of steam generator auxiliary feedwater system reserves to deal with a loss of off-site power. modelling of the physics of hydraulic flows under the reactor vessel dome (which has an impact on the definition of the safe shutdown times of the reactor when facing loss of power supply). These nonconformities are the subject of significant event notifications and are being processed accordingly with ASN oversight. Conformity examinations on the occasion of the ten-yearly periodic safety reviews: The periodic safety review conducted by EDF is an opportunity on the one hand to carry out a detailed examination of the situation of the facility, in order to check that it in fact complies with all the rules applicable to it (conformity review) and, on the other, to improve its safety level (safety reassessment) in particular by comparing the applicable requirements with those in force for facilities with more recent safety objectives and practices and by taking account of changes to available knowledge and national and international operating experience feedback. The conformity review consists more precisely in comparing the state of the facility with the safety requirements and the applicable regulations, in particular its authorisation decree and all ASN prescriptions. This conformity review aims to ensure that any evolution of the facility and its operations, due to modifications or to ageing, complies with all the rules applicable to it. This ten-yearly review does not however relieve the licensee of its permanent obligation to guarantee the conformity of its facility. In addition, the licensee implements a complementary investigation programme to consolidate the hypotheses adopted concerning the absence of damage in certain zones considered not to be susceptible and thus not covered by a preventive maintenance programme. The checks carried out under the complementary investigation programme are spot-checks and differ from one reactor to another, in order to cover all the areas concerned by maintenance. For the safety reassessment, the conformity of the equipment, structures and components is checked in terms of the compliance of their seismic strength with the reassessed baseline level. Detection of a seismic strength nonconformity during the ten-yearly outage inspections may lead to a significant event notification, processed accordingly with ASN oversight. Incorporation of international operating experience feedback: In its approach, EDF incorporated some of the operating experience feedback form the July 2007 earthquake in the Japanese power plant at Kashiwasaki-Kariwa, especially by defining the scope of seismic inspections it performed and studying the consequences of a transformer fire. Following the Fukushima accident, EDF conducted an initial series of field reviews on all its sites, which included earthquakes (specific reliability review: WANO SOER 2011-2). A number of observations were made, but none called into question the reliability of the systems.
RkJQdWJsaXNoZXIy NjQ0NzU=