- 163 - indicate what external action is planned to prevent fuel damage to the fuel, and the resources available: o equipment already on the site, for example equipment from another reactor; o equipment available off the site, assuming that all the reactors on a given site have suffered damage; o the availability of human resources; indicate the times within which the above resources can be available; identify the time within which the main cliff-edge effects occur; indicate what measures can be envisaged to prevent these cliff-edge effects or to increase the robustness of the facility (design change, change in procedures, organizational arrangements, etc.). ASN has asked EDF to take two situations into consideration for the loss of the off-site electrical power supplies and the on-site backup supplies: loss of the off-site electrical power supplies and loss of the conventional backup supplies (safeguard means in particular); loss of the off-site electrical power supplies and loss of the conventional backup supplies , and any other emergency source (including the ultimate backup means). ASN has asked EDF to take into consideration the loss of the main cooling system combined with total loss of the off-site and backup electrical power supplies, considering initially that only one reactor is affected, and in a second phase that all the facilities of a given site are affected simultaneously. Loss of the main cooling system combined with total loss of the off-site and backup electrical power supplies is not analysed for the baseline safety standard. EDF specifies in the CSA reports that the situation of total loss of the heat sink combined with total loss of the electrical power supplies has no additional impact compared with the total electrical power loss alone: as the pumps of the intermediate cooling system (CCWS) are supplied by the backed-up electrical panels, the loss of the electrical power supplies intrinsically causes total loss of the heat sink. EDF has also pointed out that the impact of an earthquake or a flood on these combined situations has been examined in the CSA reports. ASN observes that EDF has analysed loss of the main cooling system combined with loss of the off-site electrical power supplies and loss of the conventional backup power supplies. Nevertheless, in its CSA reports EDF has not analysed the loss of the main cooling system combined with loss of the off-site electrical power supplies and loss of the conventional backup power supplies and any other emergency source. ASN considers it necessary for EDF to adopt a position regarding the missing assessment. 5.3.1 Site autonomy before loss of the normal conditions of core and fuel pool cooling EDF specifies in the CSA reports that from a thermohydraulic viewpoint, this situation is identical to that described in the paragraph relative to loss of the off-site electrical power supplies and the conventional backup power supplies (see § 5.1.2). ASN does not question EDF's conclusions, but nevertheless notes that this combined situation is more penalising with regard to the recovery of the support functions, since it is not enough to simply recover an electrical power supply - it is also important to restore a heat sink. 5.3.2 External actions planned to prevent damage to the fuel Regarding the external actions planned to prevent damage to the fuel, EDF has specified in the CSA reports that in terms of facility management, the situation evoked is identical to that described in the paragraph relative to loss of the off-site electrical power supplies and the conventional backup power supplies (see § 5.1.2).
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