This standard provides (a) criteria for selecting the seismic design category1) (SDC) for nuclear facility structures@ systems@ and components (SSCs) to achieve earthquake safety and (b) criteria and guidelines for selecting Limit States for these SSCs to govern their seismic design. The Limit States are selected to ensure the desired safety performance in an earthquake. 1) The SDCs used in this standard are not the same as the SDCs referred to in the International Building Code (IBC).