GENERALITIES ON SEISMIC QUALIFICATION

Seismic qualification of items important to safety can be performed by the use of one or more of the following approaches  

It is also possible to use combinations of these methods, as shown in Fig. 1. 

Seismic qualification generally includes qualification of structural integrity as well as qualification for operability or functionality. Seismic qualification is made directly on actual or prototype items or indirectly on a reduced scale model, a reduced scale prototype or a simplified item or by means of similarity where this can be established between a candidate item and a reference item and direct qualification has been performed on the latter. Whatever the method selected, it should accurately represent the actual performance of the component or structure when it is subjected to the prescribed effects. 

Care should be taken to ensure that consistent levels of sophistication in modelling apply for all the items to be qualified. 

Any qualification programme requires that the boundary conditions applying for this item in the plant during an earthquake are correctly or conservatively simulated, or that any departure from them will not significantly influence the result. Among these conditions, the most important are excitation conditions, support conditions, environmental conditions and operational conditions. 

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