- 271 - Conformity of the facilities with the current frame of reference The licensee has not yet performed a periodic safety review of its facilities. It bases its assessment of SSC conformity on its internal inspection and maintenance system. It indicates that implementation of this organisational procedure has revealed no nonconformities. This is not sufficient to assess the conformity of the SSCs, which must undergo a proper conformity review in the short term. This review has begun for one facility, the Socatri BNI. For the Georges Besse II plant, effective conformity is verified from design through to commissioning. Evaluation of the safety margins The licensee examined the safety margins with respect to the initial design of the facilities. It concludes from the studies that a number of facilities would not withstand a Fukushima-type event. More detailed information is provided for the Georges Besse II plant. Georges Besse II plant The complementary safety assessment considers two hazard events on the Tricastin site: flow of water from the siphons of the river Gaffière attaining 300 m3.s-1 per loading on the left bank: in this case the facilities remain above water; flooding by a break in the canal embankment on the right bank between the TGV (high-speed railway) line and the NPP: in this case, according to the water heights given in the impact study conducted by SNCF TGV Méditerranée, the equipment involved in safety functions remains above water, except for the pumps and the emergency drainage system cold traps or chemical traps. The sub-criticality of these equipment items is guaranteed in case of immersion. Measures envisaged to reinforce the robustness of the facilities to the risk of flooding Additional measures were identified in the complementary safety assessments, in particular to further knowledge relating to the flood risk for the facilities in the event of increased rainfall scenarios considering the risk of the storm water drainage system being unavailable, water build-up areas due to the site configuration and the location of accesses to building containing equipment to protect, or to reinforce the measures to take in the event of flooding (operating instructions relative to stopping production in the W plant for example, implementing security measures to limit flooding of the premises and to contain the consequences of the flood within the bounds of the facility). On completion of its review, ASN considers that for the Tricastin site facilities, the specific risk of flooding of the enriched material storage areas is a particular aspect that must be taken into account. Furthermore it considers that the licensee must further reinforce the measures taken in the event of flooding. It will issue requirements on this subject. More particularly, ASN considers that AREVA must provide it with additional information concerning the available margins for the flood accident sequences considered, taking into account all site developments that could influence the water heights attained. The different nuclear licensees on the platform must also assess the margins available for the flood accident sequences considered (upstream dam burst, failure of the Donzère canal embankment, etc.) and propose any necessary reinforcements, taking into account all the site developments that could influence the water heights attained. For Socatri, ASN considers that the licensee must take the necessary measures to prevent the risk of criticality in the event of flooding of the enriched material storage areas. It shall issue requirements on this subject. 3.3.2. La Hague site Design of the facilities Owing to its location and environment (high elevation with respect to the sea, situated on the high point in the area), the La Hague site is not subject to tsunami, dam burst or flood risks. Flooding of the buildings could only result from a rise of the ground water tables or extremely heavy rainfall.
RkJQdWJsaXNoZXIy NjQ0NzU=