Document: NUREG-0800
Document ID: e8ae4ac1-29ed-46b1-b4c2-19c7f632e815
Document Type: srp
Title: DYNAMIC TESTING AND ANALYSIS OF SYSTEMS, COMPONENTS, AND
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070336.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.2
CFR Part: 
CFR Title: 

Content:
he seismic analysis of all Category I systems, components, equipment, and their supports (including supports for conduit and cable trays and ventilation ducts) DRAFT Rev. 3 - April 1996 3.9.2-8 should utilize either a suitable dynamic analysis method or an equivalent static load method, if justified. (1) Dynamic Analysis Method A dynamic analysis (e.g., response spectrum method, time history method, etc.) should be used when the use of the equivalent static load method cannot be justified. To be acceptable such analyses should consider the following items: (a) Use of either the time history method or the response spectrum method. (b) Use of an adequate number of masses or degrees of freedom in dynamic modeling to determine the response of all Category I and applicable non-Category I systems and plant equipment. The number is considered adequate when additional degrees of freedom do not result in more than a 10% increase in responses. Alternately, the number of degrees of freedom may be taken equal to twice the number of modes with frequencies less than 33 hz. (c) Investigation of a sufficient number of modes to assureensure participation of all significant modes. The criterion for sufficiency is that the inclusion of additional modes does not result in more than a 10% increase in responses. (d) Consideration of maximum relative displacements among supports of Category I systems, and components. (e) Inclusion of significant effects such as piping interactions, externally applied structural restraints, hydrodynamic (both mass and stiffness effects) loads, and nonlinear responses. (2) Equivalent Static Load Method An equivalent static load method is acceptable if: (a) Justification is provided that the system can be realistically represented by a simple model and the method produces conservative results in terms of responses. Typical examples or published results for similar systems may be submitted in support of the use of the simplified method. (b) The design and