- 258 - Measures envisaged to increase the robustness of the facilities to the seismic risk FBFC announces the renovation of building R1 (recycling of manufacturing discards), for which the file should be submitted at the end of 2012. For FBFC, ASN considers that the licensee must carry out work to reinforce building R1 used for recycling uraniferous materials, and the equipment it houses. It will issue a requirement on this subject to set the work schedule. ASN considers that the licensee must implement an automatic system for cutting off the electrical power supplies, closing the UF6 emission valves and isolating the on-site hazardous gas infeed lines on detection of an earthquake. 2.4 Other facilities (ATPu, Masurca) 2.4.1. ATPu Design of the facility This facility, which was built in 1959 with no particular anti-seismic provisions, essentially consists of blocks A, B, C, D, E and F comprising 3 levels separated by construction joints. The basement houses the radioactive materials storage and conditioning rooms, production cells and technical premises. The ground floor contains must of the manufacturing and inspection cells and storage areas for fuel elements and waste. The first floor accommodates cubicles, technical rooms and offices. The CEA indicates that blocks A and B constituting the "powder block" underwent seismic reinforcements in 1977 in accordance with the PS69 rules. Studies performed in 1994 demonstrated the need for additional seismic reinforcements. CEA however opted for closure of the facility which is currently under decommissioning. The safety functions to be guaranteed for the ATPu unit are the containment of radioactive materials and control of sub-criticality. Conformity of the facilities with the current frame of reference With regard to the civil engineering structures, CEA underlines that in an earthquake corresponding to 50% of the MHPE, the main building could collapse, which would lead to the dissemination of quantities of radioactive substances exceeding those quantified in the on-site emergency plan (PUI) and pollution of the water table, thereby leading to very serious radiological consequences. Evaluation of the safety margins The ATPu, currently under decommissioning, has no margin with respect to a seismic intensity corresponding to the MHPE. Measures envisaged to reinforce robustness to the seismic risk The licensee proposes no measures for reinforcing robustness of the facilities to earthquakes. This is because the essential measure to reduce the radiological risk associated with the ATPu consists in finalising as quickly as possible the operations to remove the radioactive substances still present and decommission the facility. These operations are governed by final shutdown and decommissioning decree No.2009-262 of 6 March 2009, which sets a time scale of fifteen year for completing facility decommissioning. Given the state of the ATPu, ASN considers that no earthquake resistance reinforcement is to be required of the licensee (requests will be made for emergency situation management).
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