Document: NUREG-0800
Document ID: 6515b846-83c3-42fc-8006-29454eea66b1
Document Type: srp
Title: -
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1319/ML13198A223.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.2
CFR Part: 
CFR Title: 

Content:
Revision 4 – September 2013 6. Three Components of Design Ground Motion. RG 1.92 describes acceptable methods for combining the responses due to three components of design ground motion, for both the response spectrum method and the time history method. Use of alternate methods is evaluated on a case-by-case basis for acceptability. When the three components of design ground motion are applied simultaneously, using a set of three time histories, the statistical independence of the time histories should be demonstrated. See Subsection II.1.B of SRP 3.7.1 for the acceptance criteria to demonstrate statistical independence. 7. Combination of Modal Responses. RG 1.92 describes acceptable methods for combination of modal responses, including consideration of closely-spaced modes and high-frequency modes, when the response spectrum method or the modal superposition time history method of analysis is used to determine the dynamic response of damped linear systems. Use of alternate methods is evaluated on a case-by-case basis for acceptability. 8. Interaction of Non-Seismic Category I Structures with Seismic Category I SSCs. All non- seismic Category I structures should be assessed to determine whether their failure under SSE conditions could impair the integrity of seismic Category I SSCs, or result in incapacitating injury to control room occupants. Each non-seismic Category I structure should meet at least one of the following criteria: A. The collapse of the non-seismic Category I structure will not cause the non- seismic Category I structure to strike a seismic Category I SSC. B. The collapse of the non-seismic Category I structure will not impair the integrity of seismic Category I SSCs, nor result in incapacitating injury to control room occupants. C. The non-seismic Category I structure is analyzed and designed to prevent its failure under SSE conditions. The disposition of each non-seismic Category I structure should be formally documented. For criterion B, it is