Complementary-safety-assessments-french-nuclear-safety

- 22 -  Cattenom: presence of water in the backup generator set fuel tanks following infiltration through the seals between buildings forming the PV between the groundwater and the buildings;  Dampierre: damaged concrete on a pumping station access hatch;  Nogent: presence of rainwater in the pumping station owing to defective openings that are part of the PV;  in Flamanville, the "civil engineering" basic maintenance programme for the site only makes provision for visual inspection of the embankment, with no underwater inspection. The embankment check-out showed that the tip of the intake channel embankment was sinking significantly. Furthermore, correction of the anomalies affecting the PV is sometimes a lengthy process (6 months at Dampierre, 8 months at Cattenom) or not even traced (at Saint-Laurent, for example, there is no complete record of the installation of the flood panels, despite the presence of a problem with the lifting resources). The inspectors noted that on several sites, the seals between buildings had no expiration date. In this case, ASN considers that regular monitoring will be required. ASN finds that the monitoring and upkeep of the protection systems need to be improved as a whole. 2.1.10 Mobile pumping resources (MMP) The inspectors questioned the sites concerning the mobile pumping resources (MMP) available in the event of flooding. Following the meeting of the advisory committees (for reactors and for laboratories and plants) on 21st and 22nd March 2007, the capacity and number of MMP were validated for all the sites. The number of MMP and their capacity varies according to the site's vulnerability and the number of reactors (8 pumps at Dampierre and Cattenom, 6 at Bugey, Saint-Alban and Blayais, 3 at Belleville, 1 at Flamanville, 4 at Saint-Laurent, 11 pumps at Tricastin). These mobile pumping resources are managed by specific flood reports or by reports related to the PUI safety requirements (for example Bugey) detailing their management and their location. These mobile pumping resources are sometimes subject to annual preventive maintenance (Cattenom, Fessenheim, Tricastin) but this is often not the case (Dampierre, Gravelines), in particular concerning the hoses; nonetheless, some sites have decided to draft memos to initiate these checks (Nogent, SaintLaurent). Finally, the inspectors point out that this maintenance must be staggered, so that a minimum number of MMP is guaranteed to be available on the site (unlike at Tricastin, for instance, which performs all its tests on the same day off the site and which, in the event of flooding, then has no other pumping resource). Finally, some pumps are not equipped with a meter giving warning of the saturation of the tanks. ASN finds that MMP management on the sites needs to be improved. For those sites with mobile pumping resources, the equipment is in good condition and sometimes stored in dedicated areas. For all the sites questioned, the MMPs are specific to flood management and are not required for firefighting purposes, a fact that ASN considers to be satisfactory. 2.1.11 Powering the pumps after loss of off-site power supplies Most sites have fuel tanks and electricity generating sets, but their number and their operating capacity vary from site to site, in particular between those sites impacted by a loss of off-site power in the event of flooding and those which are not. The operating time is linked to the fuel capacity and the possibility of fuel resupply. The case of the Tricastin site must be highlighted as it only has a single electricity generating set for supplying pumps remote from power sources. It complies with the requirements of the flood frame of reference of 2004, but does not take account of the risk off losing off-site power supplies in the event of flooding. This must therefore be reviewed in the light of the 2011 flood RPC, which modifies this diagnostic and considers the site to be exposed to LOOP (loss of off-site power) in the event of flooding. The Le Blayais site must also test the procedures planned in the event of a loss of off-site power, that is installation of a bypass system by RTE (the Electricity Transmission System). ASN finds that the power supply to the pumps in the event of LOOP needs to be improved.

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