Document: NUREG-0800
Document ID: 29f5ac9f-4962-4021-913a-6375076e03fd
Document Type: srp
Title: SEISMIC SYSTEM ANALYSIS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340566.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.2
CFR Part: 
CFR Title: 

Content:
esponse combination. When modes with closely spaced modal frequencies exist (two modes having frequencies within 10 percent of each other), the methods delineated in Reference 8 are acceptable. Use of other methods for considering closely spaced modes, such as those outlined in References 4 and 9 will be reviewed and accepted on a case-by-case basis. Acceptance criteria for the adequate consideration of high-frequency modes are provided in Appendix A to this SRP section. B. Interaction of Non-Category I Structures with Category I Structures To be acceptable, the interfaces between Category I and non-Category I structures and plant equipment must be designed for the dynamic loads and displacements produced by both the Category I and non-Category I structures and plant equipment. In addition, a statement indicating the fact that all non-Category I structures meet any one of the following requirements should be provided. a. The collapse of any non-Category I structure will not cause the non-Category I structure to strike a seismic Category I structure or component. b. The collapse of any non-Category I structure will not impair the integrity of seismic Category I structures or components. c. The non-Category I structures will be analyzed and designed to prevent their failure under SSE conditions in a manner such that the margin of safety of these structures is equivalent to that of Category I structures. 9. Effects of Parameter Variations on Floor Response Spectra Consideration should be given in the analysis to the effects on floor response spectra (e.g., peak width and period coordinates) of expected variations of structural properties, dampings, soil properties, and soil-structure interactions. The acceptance criteria for the considera- tion of the effects of parameter variations are provided in subsection I1.5 of this SRP section. 10. Use of Equivalent Vertical Static Factors The use of equivalent static load factors as vertical response loads for the seismic