Document: NUREG-0800
Document ID: 6b7eddf4-f7ce-4821-9f11-e37070221e57
Document Type: srp
Title: DYNAMIC TESTING AND ANALYSIS OF SYSTEMS, STRUCTURES, AND
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1613/ML16133A418.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.2
CFR Part: 
CFR Title: 

Content:
eas of review identified in subsection I.2 of this SRP section are described below. Other approaches that are justified as equivalent to or more conservative than the stated acceptance criteria may be used to confirm the ability of all seismic Category I systems and components and their supports to function as needed during and after an earthquake. A. Seismic Analysis Methods. The seismic analysis of all seismic Category I systems, components, equipment, and their supports (including supports for conduit and cable trays and ventilation ducts) should utilize either a suitable dynamic analysis method or an equivalent static load method, if justified. (i) Dynamic Analysis Method. A dynamic analysis (e.g., response spectrum method or time history method) should be performed when the use of the equivalent static load method cannot be justified. To be acceptable, such analyses should address the following items: (1) Use of either the time history or the response spectrum method. (2) Use of an adequate number of mass degrees of freedom in dynamic modeling. SRP Section 3.7.2, Subsection II.1.A.iv provides detailed acceptance criteria for selecting an adequate 3.9.2-16 Revision 4 – March 2017 number of discrete mass degrees of freedom in dynamic modeling, to determine the response of all seismic Category I and applicable non-seismic Category I systems and plant equipment. (3) Investigation of a sufficient number of modes to ensure participation of all significant modes. When using either the response spectrum method or the modal superposition time history method, all modes with frequency f ≤ zero period acceleration (ZPA) frequency should be explicitly included in the analysis. As identified in SRP Section 3.7.2, Subsection II.1.A.v, the additional response associated with high frequency modes (i.e., f > ZPA frequency) should be included in the total dynamic solution using the guidance and methods described in RG 1.92, "Combining Modal Responses and Spatial Components in