Document: NUREG-0800
Document ID: acdd814e-c3ba-4fc6-9914-b7afbf7eddee
Document Type: srp
Title: -
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1319/ML13198A223.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.2
CFR Part: 
CFR Title: 

Content:
Revision 4 – September 2013 Any other modeling methods used for SSI analysis are also reviewed, as is any basis for not using an SSI analysis. For a DC application, the number and characteristics of generic site profiles are reviewed to ensure that there is an adequate seismic design basis for a standard plant. 5. Development of In-Structure Response Spectra. The procedures and methods for developing in-structure response spectra (e.g., floor response spectra) are reviewed. There are several methods for generating in-structure response spectra (ISRS). One method makes use of time history analysis by considering single or multiple (real or artificial) ground motion time histories which have response spectra that satisfy the enveloping criteria for the design ground response spectra and the target power spectral density (PSD) function. A second method, which does not require time history analysis, is generally referred to as direct generation of ISRS. The basis and justification for the use of either of the above methods are reviewed. 6. Three Components of Design Ground Motion. The staff reviews the procedures by which the three components of design ground motion (time history or response spectra) are considered in determining the seismic response of all seismic Category I SSCs. If three design ground motion time histories (two horizontal and one vertical) are applied in a single time history analysis, the statistical independence among the three components is also reviewed. 7. Combination of Modal Responses. When a modal time history analysis method or a response spectrum analysis method is used to calculate the seismic response of SSCs, the contribution to the total response due to the effects of high frequency modes (i.e., modes with natural frequencies greater than the frequency at which the spectral acceleration converges to approximately the zero period frequency, (ZPA) is reviewed, to ensure that the total response closely simulates the behavior of the SSC