- 159 - Ultimate make-up means for all the reactors: EDF proposes implementing an ultimate make-up means by pumping water from the water table or largecapacity ponds using a stand-alone motor-driven pump or an electric pump backed by the ultimate backup diesel generator (DUS). This system will be a fixed installation on all the sites and will allow the make up of the EFWS and PTR tanks and the spent fuel pools (before 2015). EDF has confirmed that the make-up means and its supporting systems will be dimensioned for the needs of the entire site. The output will be sufficient to supply the spent fuel pool building (BK) and either the EFWS tank or the PTR tank simultaneously. Ultimate make-up means from the demineralisation plant water supply system (SEA) ponds (Paluel, Penly and Flamanville sites) The demineralisation plant water supply system (SEA) ponds at the Paluel, Penly and Flamanville sites are situated on the cliff (total capacity of 150,000 m3 at Flamanville, 36,500 m3 at Penly and 36,000 m3 at Paluel). The CSA reports for Flamanville 1-2 and 3 and Penly 3 indicate that the ultimate make-up will be made from these ponds. For Penly 1-2 and Paluel, an ultimate make-up means by pumping water from the water table or tanks is mentioned but not detailed. During the examination, EDF pointed out that for these three sites (all plant units), the ultimate make-up would be provided by the existing SEA ponds. These ponds are not included in the safety demonstration at present, therefore they are not safety-classified and have no seismic requirement. EDF nevertheless indicates that they are stable under the stresses of the SSE (safe shutdown earthquake), and even beyond. The ponds are connected to the demineralisation plants by two pipes (SEI - industrial water system) which are not designed to withstand an earthquake at Flamanville and Paluel but are at Penly (level not specified). The risk of rupture of the SEI pipes is studied for Flamanville and Paluel, as EDF considers that the consequences of complete emptying of the ponds are acceptable with respect to the flood risk (water retained in the galleries and turbine halls). As regards the ultimate make-up function of the ponds, EDF indicates that it will make the valve chamber and the SEI pipes earthquake resistant at Flamanville (not specified for Paluel). ASN considers that if the SEA ponds and the SEI pipes and valves are to be part of the ultimate defence against H1 situations, or even a severe accident, including situations induced by an earthquake exceeding the baseline safety standard, they must be included in the "hard core" of tightened material and organisational provisions. Ultimate make-up means at Civaux and Cattenom These sites have large water reservoirs which constitute the backup heat sink (ponds at Civaux giving an autonomy of 10 days, Mirgenbach lake at Cattenom giving an autonomy of 30 days ). ASN emphasizes that the earthquake-resistance stability of the Mirgenbach lake dam at Cattenom "presents moderate margins beyond the SSE" according to chapter 4 of the CSA reports. For these sites like the others, the CSA reports mention the implementation of long-lasting ultimate water make-up means (pumping from the water table, ponds, etc.) for the EFWS and PTR tanks and the spent fuel pools. ASN considers that the characteristics of the ultimate means envisaged by EDF must satisfy the requirements assigned to the systems, structures and components of the "hard core" of tightened material and organisational provisions. Particular case of the Flamanville 3 EPR The complementary measures envisaged by EDF concern, among other things, the ultimate make-up of the EFWS tanks and the spent fuel pool with water from the ponds of the demineralisation plant water supply system (SEA), and reinforcement of the ultimate backup diesel generators. The ultimate water make-up solution for the spent fuel pool envisaged by EDF by gravity feed from the SEA ponds could compensate for the evaporation losses and enable a minimum water level to be maintained once the JAC water reserves are exhausted. The autonomy provided by the ponds considerably increases the time lapse before the fuel assemblies stored in the rack become exposed. For the whole-site situation, pooling of water reserve utilisation is envisaged, which will reduce the gain in autonomy compared with the single plant unit situation.
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