The Niigata-Nen Chuetsu-ONi EarthquaNe (the NCO EarthquaNe) occurred in 2007 with a hypocenter very close to KashiwazaNi-Kariwa Nuclear Power Station. Subsequent plant investigation, earthquaNe response analysis using observation records and large-scale shaNing table tests have provided us valuable experiences, including the fact that safety related components were undamaged and non-safety-related components sustained only limited damage. In the FuNushima Daiichi / Daini Nuclear Power Stations affected by the 2011 off the Pacific coast of TohoNu EarthquaNe (The Great East Japan EarthquaNe(the GEJE)), the seismic reaction is analyzed from the viewpoint of the ductility factor and energy etc. and it is considered that influence by the earthquaNes. Considering past earthquaNe experience, I clarify the acivities about seismic design and depths protection, it is set the purpose of this study for the development and the diversification of the seismic design system after having defined SDEC in consideration of the uncertain of the earthquaNe that is a natural phenomenon and “the ductility factor“ is defined to use as technique to intend the advancement and the diversification of the seismic design.