- 259 - 2.4.2. Masurca Design The MASURCA facility was designed in accordance with the provisional "PS 62" paraseismic rules. This facility is currently shut down and will be renovated as from 2015. The licensee considers that its stability is globally ensured for an SSE that is established taking into account the true distance between the site and the Middle-Durance fault. Measures to protect the facilities against the seismic risk The design measures concern the civil engineering of the storage and handling building (BSM) and the storage compartments of the fissile materials storeroom, which were designed to the reference spectrum applicable in 1964 when the facility was built. The operating measures implemented to mitigate the consequences of an earthquake are described in a specific procedure concerning the post-earthquake actions. The main measure is to cut off the supplies of electricity, water, diesel fuel, argon-CO2 to avoid the risks of indirect effects following an earthquake. The identified indirect effects considered in the analysis are the loss of all the electrical power supplies, damage to the electrical systems that could produce a short circuit and start a fire, and rupture of the water pipes in the BSM, causing water to flow around the fissile materials. The CEA indicated that these indirect effects were not such as to generate an additional cliff-edge effect. The analysis of the earthquake behaviour of the civil engineering structures is based essentially on an opinion of experts. On 30 June 2011 the reactor was unloaded and only the BSM building contained nuclear materials. A facility renovation project is currently in progress, with the planned construction of a new storage building to replace the BSM (entry into service planned for 2017). Conformity of the facilities with the current frame of reference The CEA reports a diagnosis revealing that the current design of the BSM does not meet the safety requirements in the event of the SSE earthquake defined per RFS 2001-01 for all the Cadarache site facilities. Evaluation of the safety margins In view of the foregoing, the facility in its current state has no safety margin. With regard to the stability of the storage and handling equipment (storage compartments and overhead travelling stacking crane) in the event of an earthquake, the CEA points out that they are not directly involved in the containment but can play a role in the prevention of the criticality risk. According to the CEA they display margins significantly higher than those of the civil engineering. Consequently, the main risk feared is the destruction of the BSM building, which would lead to destruction of the equipment and loss of containment. The risk of instability of the storage and handling equipment items in themselves is not feared. Measures to improve the safety of the facility - Opinion of ASN The CEA points out that a specific complementary assessment of the renovated facility configuration will be presented as part of the renovation project file review. Pending availability of this new building, the measures envisaged consist in limiting the quantity of water that could be spread over nuclear materials following a break in the water pipe supplying the BSM by: shutting off the municipal water feeder supplying a shower and wash-hand basin (the equipment in the locker/changing room building can be used); shutting off and draining of the air-conditioning chilled water system.
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