Document: NUREG-0800
Document ID: 585516eb-af20-45dc-a470-9638ec9381f3
Document Type: srp
Title: Each calculated spectrum of the artificial time history is considered to envelop
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0706/ML070640306.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.0
CFR Part: 
CFR Title: 

Content:
t SSI effects and the expected duration of the vibratory motion. If the OBE is set at one-third or less of the SSE, an explicit analysis or design is not required. If the OBE is set at a value greater than one-third of the SSE, an analysis and design must be performed to demonstrate that the applicable stress, strain, and deformation limits are satisfied. Appendix S also requires that the horizontal component of the SSE ground motion in the free-field at the foundation level of the structures must be an appropriate response spectrum with a peak ground acceleration of at least 0.1g. SRP Section 3.7.1 describes acceptance criteria for developing the required earthquake loadings consisting of the SSE and OBE (if applicable) and other seismic design parameters needed to perform an SSI analysis. This SRP section indicates that an explicit analysis for the OBE, in addition to the SSE, should be performed unless the magnitude of the OBE is set at one-third or less of the SSE. Criteria for the required characteristics of the earthquake motion are presented which include the duration of the seismic ground motion. SRP 3.7.1 also specifies that the horizontal free-field SSE ground motion at the foundation level shall be represented by an appropriate response spectrum, such as that defined in Regulatory Guide 1.60, with a minimum peak ground acceleration of 0.1g.The criteria presented in this SRP section provide the earthquake loadings and seismic design parameters so that the SSI analysis can determine the response of the SSCs in terms of stresses, strains, and deformations. In addition, the use of these criteria allow the SSI analysis to calculate the floor response spectra for use in qualification of equipment. Meeting these requirements provides assurance that appropriate methods will be used to determine the required OBE and SSE loadings and the response of SSCs, which will ensure that they will remain functional within applicable acceptance limits. III. REVIEW PROCEDURES