Document: NUREG-0800
Document ID: a8564bea-31bf-4592-ba45-e92b53d2d706
Document Type: srp
Title: SEISMIC SUBSYSTEM ANALYSIS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340570.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.3
CFR Part: 
CFR Title: 

Content:
data have been accumulated. 2. Appendix A to 10 CFR Part 100 - Two earthquake levels, the safe shutdown earthquake (SSE) and the operating basis earthquake (OBE), shall be considered in the design of safety-related structures, components, and systems. Appendix A to 10 CFR Part 100 further states that the design used to ensure that the required safety functions are maintained during and after the vibratory ground motion associated with the safe shutdown earthquake shall involve the use of either a suitable dynamic analysis or a suitable qualification test to demonstrate that structures, systems, and components can withstand the seismic and other concurrent loads, except where it can be demonstrated that the use of an equivalent static load method provides adequate conservatism. Specific criteria necessary to meet the relevant requirements of GDC 2 and Appendix A to Part 100 are as follows: 1. Seismic Analysis Methods The acceptance criteria provided in SRP Section 3.7.2, subsection II.1, are applicable. 2. Determination of Number of Earthquake Cycles During the plant life at least one safe shutdown earthquake (SSE) and five operating basis earthquakes (OBEs) should be assumed. The number of cycles per earthquake should be obtained from the synthetic time history (with a minimum duration of 10 seconds) used for the system analysis, or a minimum of 10 maximum stress cycles per earthquake may be assumed. 3. Procedures Used for Analytical Modeling The acceptance criteria provided in SRP Section 3.7.2, subsection II.3, are applicable. 3.7.3-3 Rev. 2 - August 1989 4. Basis for Selection of Frequencies To avoid resonance, the fundamental frequencies of components and equipment should preferably be selected to be less than 1/2 or more than twice the dominant frequencies of the support structure. Use of equip- ment frequencies within this range is acceptable if the equipment is adequately designed for the applicable loads. 5. Analysis Procedure for Dampinq The acceptance