Document: NUREG-0800
Document ID: 8e07b880-6f70-4aba-8fed-a47a4d8a6666
Document Type: srp
Title: -
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1235/ML12353A354.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.2
CFR Part: 
CFR Title: 

Content:
ent because the site profile frequency characteristics determine the amplification of the input ground motion through the site. Using a seismic SSI analysis, the seismic ground motion input spectra is propagated through the site profiles into the structure in terms of seismic response or demands for design of structural members and supported equipment. The amplification of the input ground motion occurs at the profile column frequencies. Therefore, a CSDRS containing significant amplification at frequencies other than those of the profile columns will not be amplified in structural demands through the postulated site profiles. The proposed criterion ensures that the CSDRS should be shown to be appropriate for the postulated site profiles in frequency content by demonstrating that there is a reasonable distribution of the site profile column frequencies over the amplified portion of the CSDRS. The proposed enhancement improves the SRP guidance in the following aspects: (1) it includes the consideration of the generic site profiles in the scope of the review and the corresponding appropriate CSDRS to ensure an adequate seismic design basis; (2) it clarifies that for a COL application referencing a standard plant design, where the site- specific GMRS fall below the standard plant CSDRS, it is also necessary to confirm that the site-specific, strain-dependent soil properties, including consideration of uncertainty, are consistent with the generic site profiles used in the standard plant design. If this is not the case, then a site-specific SSI analysis is needed; and (3) for a DC application, the CSDRS should be shown to be appropriate for these postulated site profiles in