- 240 - With regard to the pools and associated systems, the following have been deigned to withstand earthquakes: the pools themselves; the equipment for controlling sub-criticality (devices implemented in the storage of fuel elements such as storage structures and racks; pool water level gauges, particularly that triggering emergency shutdown); the equipment contributing to the containment of radioactive materials (pool and canal liners, etc.); the residual power removal equipment (backup cooling systems in particular); the radiological monitoring equipment. The licensee has also taken operating measures with respect to the seismic risk that concern the heavy handling means (polar crane, travelling crane, main bridge of the pools), which when not in use are placed in a parked position away from areas housing elements important for safety; a programme for monitoring the paraseismic supports; measures for the maintenance of the drains of the nailed wall and limitation of heavy load handling heights. Conformity of the facility Conformity of the facility shall be verified as construction progresses, through the qualification of the required materials and the acceptance and commissioning programme. Evaluation of the safety margins With regard to the civil engineering structures, the CEA has evaluated the margins by determining the earthquake level beyond which the safety functions would no longer be ensured. The CEA indicated that this approach revealed the weak spots of a facility and allowed the envisaging of measures to improve its robustness and prevent "cliff-edge" effects. This level of earthquake is expressed with reference to the design-basis earthquake (DBE), whose spectrum already encompasses the Cadarache SSE and paleoearthquake spectra determined by application of RFS 2001-01. The following JHR civil engineering structures were studied using this procedure: supporting of the nuclear unit (UN) consisting of the paraseismic supports, the concrete blocks and the lower basemat; the reactor pool (RER); the intermediate pool (REE); the water block bunkers; the pools of the nuclear auxiliary building (BUA); the safeguard buildings (BAS) and the connection galleries (BAG); the BUA roof; the potential hazards for the structures whose integrity or stability must be maintained: the locker and changing room building (BAV), the gallery connecting the BAV to the UN, the nailed wall. The margins were determined with reference to the dimensioning criteria. The CEA also evaluated the margins on the capacity of certain structures (BAS and BAG) to dissipate energy through ductile behaviour. For the equipment, the CEA examined the electrical power sources, the safeguard systems, the immersed storage baskets, compartments and racks, the pool bridge and the polar crane of the reactor building (BR). The safety margin factors evaluated by the CEA for these equipment items vary from 1.4 to 2. For the safeguard pipes, international experience feedback indicates a margin of 3 with respect to the DBE. From simplified calculations the CEA estimates that the stability of the immersed baskets, racks and compartments is ensured for at least 1.4 DBE. CEA's analysis for the BR polar crane, designed to remain stable in a design-basis earthquake in an unfavourable position with its maximum load, concluded on a margin of more than 2 with respect to the DBE. As regards containment integrity, the licensee announces an overall margin of 2 with respect to the DBE. The BUA cranes are still to be analysed, as their design is not yet completed.
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