- 16 - 2. Summary of the pressurised water reactor (PWR) targeted inspections carried out in 2011 on topics related to the Fukushima accident Summary of the inspections The inspections showed that the five subjects targeted by the programme were not always correctly integrated into the current frame of reference. The main steps to be taken by EDF are summarised below. 1. With regard to the topic of flooding, the conclusions of the inspections are diverse and vary according to the sites. ASN considers that the organisation put into place to manage the flooding risk complies satisfactorily with the expectations. However, ASN does consider that the management of volumetric protection1 needs to be improved on some of the sites inspected. EDF will therefore focus its efforts in particular on the monitoring and maintenance of volumetric protection. ASN also considers that EDF needs to define and implement exercises for testing the ability of the equipment and crews to deal with this type of situation and to incorporate experience feedback from these exercises. Finally, ASN considers that improvement is required on the following topics: the strict application on the sites of special operating rules in the event of flooding; monitoring of meteorological, flood and tide parameters; the schedule for the performance of actions decided on in the light of the experience feedback from the partial flooding of the Le Blayais site in 1999; management of mobile pumping resources. 2. With regard to the topic of earthquakes, ASN finds that the inspections revealed shortcomings on several sites and that progress is required on all the sites as a whole. It is important to conduct exercises simulating an earthquake leading to the implementation of planned procedures and to prepare the personnel for this type of situation. ASN moreover considers that greater consideration must be given to the event-earthquake problem in the procedures and day-to-day operations of the units. Finally, EDF must ensure compliance with RFS I.3.b2 concerning seismic instrumentation, in particular with regard to operator familiarity with the equipment, its upkeep and its calibration. On the whole, ASN considers that this subject requires permanent vigilance on the part of EDF, so that the potential implications of a hazard of this nature during the day-to-day operation of the reactors are not lost. EDF informed ASN that it has already taken steps in response to ASN's findings (seismic risk awareness campaigns launched on all the sites, appointment of a local seismic coordinator, currently ongoing checks of the positioning of the seismic measurement sensors, and updating of procedures). ASN considers that this subject should be the focus of priority action in 2012. 3. ASN finds that the heat sink, which plays a fundamental safety role, requires particular vigilance. Recent heat sink clogging or partial loss of heat sink events, at Cruas and Fessenheim in December 2009 in particular, revealed its vulnerability and led EDF to initiate a plan of action to enhance the robustness of all the heat sinks. ASN asked EDF to conduct a design review of all heat sinks. ASN will be asking EDF for the detailed conclusions of this design review, site by site, along with the associated plan of action with its milestones and deadlines. The inspections carried out by ASN in 2011 showed that the general condition of the facilities was correct but that a certain number of problems still persisted on certain sites. Rigorous operation and maintenance, monitoring of the condition of the equipment and structures, and exhaustive application of the national directives are as a general rule areas of improvement for many sites. At numerous sites, maintenance of the SEC (Essential Service Water) system needs to be improved. 1In a flooding situation, the equipment designed to ensure reactor safety must remain operational. Therefore, when necessary, systems are thus put into place to protect against the various hazards that could lead to flooding. This protection is based on several lines of defence (embankments, walls, water drainage networks, etc.), including volumetric protection. The perimeter of volumetric protection, which encompasses buildings containing equipment designed to guarantee reactor safety, was defined by EDF to guarantee that the arrival of water outside this perimeter does not lead to flooding of the premises situated inside the perimeter. In concrete terms, the volumetric protection consists of walls, ceilings and floors. Protection of existing openings in these walls (doors, other openings, etc.) can constitute potential points of water ingress in the event of flooding. 2 RFS I.3.b of 8th June 1984 concerning seismic instrumentation.
RkJQdWJsaXNoZXIy NjQ0NzU=