Document: NUREG-0800
Document ID: 91dd5605-fced-4aa9-82f4-b0def4175216
Document Type: srp
Title: Safe Shutdown Earthquake. In meeting the requirements of Ref-
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340591.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.5.2.6
CFR Part: 
CFR Title: 

Content:
erence 1, this subsection is accepted when the vibratory ground motion specified for the SSE is described in terms of the free-field response spectrum and is at least as conservative as that which would result at the site from the maximum earthquake (determined in Subsection 2.5.2.4) consider- ing the site transmission effects (determined in Subsection 2.5.2.5). If several different maximum potential earthquakes produce the largest ground motions in different frequency bands (as noted in Subsection 2.5.2.4), the vibratory ground motion specified for the SSE must be as conservative in each frequency band as that for each earthquake. The staff reviews the free-field response spectra of engineering significance (at appropriate damping values). Ground motion may vary for different founda- tion conditions at the site. When the site effects are significant, this review is made in conjunction with the review of the design response spectra in Section 3.7.1 to ensure consistency with the free-field motion. The staff normally evaluates response spectra on a case-by-case basis. The staff considers compliance with the following conditions acceptable in the evalua- tion of the SSE. In all these procedures, the proposed free-field response spectra shall be considered acceptable if they equal or exceed the estimated 84th percentile ground-motion spectra from the maximum or controlling earth- quake described in Subsection 2.5.2.4. 2.5.2-6 Rev. 2 - August 1989 The following steps summarize the staff review of the SSE. 1. Both horizontal and vertical component site-specific response spectra should be developed statistically from response spectra of recorded strong motion records that are selected to have similar source, propaga- tion path, and recording site properties as the controlling earthquake(s). It must be ensured that the recorded motions represent free-field condi- tions and are free of or corrected for any soil-structure interaction effects that may be present because of