Document: NUREG-0800
Document ID: 10bc45c3-8e70-44ed-a57b-2dd08d4ef847
Document Type: srp
Title: SEISMIC SUBSYSTEM ANALYSIS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0706/ML070640313.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.3
CFR Part: 
CFR Title: 

Content:
ualify subsystems important to safety, and thereby ensure that they will be able to perform their intended safety function when subjected to the SSE and OBE (if applicable). 3.7.3-9 Revision 3 - March 2007 3. 10 CFR Part 50, Appendix S is applicable to applications for a design certification or combined license to 10 CFR Part 52 or a construction permit or operating license pursuant to 10 CFR Part 50 on or after January 10, 1997. For SSE ground motions, 10 CFR Part 50, Appendix S requires that SSCs will remain functional and within applicable stress, strain, and deformation limits. The required safety functions of SSCs must be assured during and after the vibratory ground motion through design, testing, or qualification methods. The evaluation must take into account soil-structure interaction effects and the expected duration of the vibratory motion. If the OBE is set at one-third or less of the SSE, an explicit response or design analysis 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. SRP Section 3.7.3 describes acceptable analytical methods that are used to determine the seismic response of subsystems in terms of stresses, strains, and deformations. These responses are combined with the structural responses from other loads in accordance with the criteria in SRP Section 3.8. The criteria in SRP Section 3.7.3 ensure that the effects of soil-structure interaction and expected duration of the earthquake are appropriately included in the evaluation. In addition, criteria is provided to indicate when the effects of the OBE are required to be considered explicitly in the seismic design of the subsystems. Meeting these requirements provides assurance that appropriate methods will be used to determine the structural response of subsystems, under the SSE and OBE (if applicable), which will ensure that they will