Updated design of the IRIS nuclear reactor seismic isolation system and seismic analysis in beyond project design condition

This document updates the document [1]: ACS - P9LU - 001. Only the new results are included here. The isolation frequency was chosen in the document mentioned before and it will be maintained in order to keep the maximum horizontal displacement close to 100 mm. Thus the global stiffness of the isolation system must be maintained (1570kN/mm). This document besides presents the numerical analysis results performed in order to investigate the maximum peak ground acceleration that can be accepted by the isolation system in case of beyond project earthquake, without failures and maintaining the normal functionality.