- 141 - some of these material resources could be provided by the "FARN" (Nuclear Rapid Intervention Force)33; to equip the sites in the short term with high-power mobile stand-alone lighting equipment to facilitate interventions on the premises; to draft an operating document for the situation of loss of off-site electrical power supplies and the backup energy sources; to update the current operating procedure as part of a modification of the chapter VI procedures of the general operating rules (GOR): o anticipation of rapid cooling, o limiting of steam generator depressurisation; for the 900 MWe series and for states where the primary system is just open, to change the primary system pressure build-up procedure to remove the residual power by the steam generators, thereby having sufficient secondary pressure to supply the required turbine-driven auxiliary feedwater pump and maintain the required SG water inventory when the primary system can be repressurised; to modify the operating documents so that the necessary measures are taken as soon as loss of the heat sink or total loss of the electrical power supplies is confirmed, without waiting for deployment of the on-site emergency plan (PUI); to study the complementary operating measures, notably by providing charts to evaluate the TAC or the GUS for management of the spent fuel pools in these situations; to study the appropriateness of having a generator set to back up the information strictly necessary for managing loss of the spent fuel pool cooling; ultimately, to study the feasibility of transferring control of the existing spent fuel pool make-up system to premises totally protected against the effects of steam and improve the functioning of the steam vent. For the EPR reactor, to prevent cliff-edge effects or to increase the robustness of the facility, EDF has proposed in its CSA reports: to implement a mobile means of pumping fuel from the main generator set tanks to resupply the SBO generators, should it be impossible to obtain fuel from the exterior; to envisage resupplying the ASG system tanks from the freshwater ponds of the demineralized water production system (SEA); to study and implement means of controlling the explosion risk resulting from radiolysis of the spent fuel pool water if there is no ventilation; to implement a passive or automatic system for opening the fuel pit area vent to improve the prevention of a pressure build-up situation in the fuel pit area; to implement gravity make-up of the spent fuel pool with water from the SEA ponds via an external connection with the fuel building, that will compensate for water losses by evaporation and at least maintain the water level; to study the measures to take to increase the robustness of the fuel pool instrumentation (water temperature, water level, dose rate in the fuel pit area) for managing the situation, and water top-up in particular. ASN considers that EDF's electricity supply backup proposals, which comply with the CSA specifications, must be implemented. EDF has identified the need to keep information vital for operations management available in the control room and to maintain control room lighting. However, it has not assessed the risk of a cliff-edge effect associated with certain information losses in the control room, with exhaustion of the batteries and the absence of lighting in situations with the primary system open or LLS unavailable. ASN notes that EDF's proposal to deploy one or 33 See § 6 of this chapter
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