- 96 - electrical and diesel buildings) shall be analysed by EDF in the study that ASN will ask it to conduct on the incorporation of long-term H1 or H3 site situations (see § 5). It is important to note that updating of the site SSE is simply one part of the periodic safety reviews concerning seismic aspects. The development of computing methods and resources utilized by paraseismic engineering has helped fine-tune the evaluation of the seismic strength of buildings and equipment. Reinforcements can thus be decided, not solely on the basis of a reassessment of the hazard, which constitutes input data for the design of structures and equipment, but also on the basis of changes to paraseismic engineering. Thus, the seismic modifications implemented during the VD3 at Fessenheim, are not due to a reassessment of the seismic hazard, but to the use of new computing methods. Seismic operating experience feedback (nuclear and non-nuclear) and construction robustness design studies are also sources for the evaluation of seismic conformity. In addition to the initial seismic design of the facility, ASN made specific requests on the occasion of the second and third ten-yearly outage reactor inspections, to take account of changes to the baselines and to available scientific data in the field of the hazard and the paraseismic justification. ASN considers that the seismic reassessments conducted since the design of the units, based on reassessed hazards and changes to paraseismic justification methods, were performed satisfactorily. ASN noted the conformity of the reactors with this baseline, subject to the implementation of identified reinforcements and changes, scheduled for the ten-yearly outages. 2.1.2 Steps designed to protect the facilities from the earthquake for which they are designed Identification of systems, structures and components (SSCs) for which availability is required subsequent to an earthquake The plant shall be designed so that it can be restored to and kept in safe shutdown conditions after an earthquake corresponding to the SSE. The licensee shall demonstrate that it meets the three safety objectives: controlled reactivity (including the safe shutdown function), residual heat removal, containment of radioactive materials. These objectives are the responsibility of equipment, systems and structures to which behaviour requirements are attributed (integrity, functional capability, operability). integrity: applies to pressure vessels playing a safety role; it aims to maintain the containment capacity. functional capability: aims to maintain the function of a system for a mission duration defined in the safety analysis report. operability: aims to ensure correct working of the mobile parts and mechanisms, for performance of the safety functions of this equipment and the nominal working of actuators and control systems. During the design process, the equipment, systems or structures necessary for the safety demonstration are classified on a list of elements important for safety. Depending on its safety role, this equipment is placed in a safety class which comprises seismic classification requirements defined by the regulations or by the RFS (RFS IV.1.a of 21st December 1984 concerning the classification of certain mechanical equipment, RFS IV.1.b concerning the design and classification of safety-class electrical equipment, etc.). These elements are designed to perform their functions in all plant operating situations (normal, transient, incident and accident). The behaviour requirements are determined by the role to be played by the equipment, systems or structures in the various operating situations.
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