Document: NUREG-0800
Document ID: 10bc45c3-8e70-44ed-a57b-2dd08d4ef847
Document Type: srp
Title: SEISMIC SUBSYSTEM ANALYSIS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0706/ML070640313.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.3
CFR Part: 
CFR Title: 

Content:
lations should be the same as the guidance provided in SRM for SECY-93-087 dated July 21, 1993 for piping systems. The number of earthquake cycles to consider are two SSE events with 10 maximum stress cycles per event. This is considered to be equivalent to the cyclic load basis of one SSE and five OBEs. Alternatively, the number of fractional vibratory cycles equivalent to that of 20 full SSE vibratory cycles may be used (but with an amplitude not less than one-third of the maximum SSE amplitude) when derived in accordance with Institute of Electrical and Electronics Engineers (IEEE ) Standard 344-1987, Appendix D. 3. Procedures Used for Analytical Modeling. The acceptance criteria provided in SRP Section 3.7.2, subsection II.3, are applicable. 4. Basis for Selection of Frequencies. To avoid resonance, the fundamental frequencies of components and equipment should preferably be selected to be less than ½ or more than twice the dominant frequencies of the support structure. Use of equipment frequencies within this range is acceptable if the equipment is adequately designed for the applicable loads. 5. Analysis Procedure for Damping. The acceptance criteria provided in SRP Section 3.7.2, subsection II.13, are applicable. 6. Three Components of Earthquake Motion. The acceptance criteria provided in SRP Section 3.7.2, subsection II.6, are applicable. 7. Combination of Modal Responses. The acceptance criteria provided in SRP Section 3.7.2, subsection II.7, are applicable. 3.7.3-5 Revision 3 - March 2007 8. Interaction of Other Systems With Seismic Category I Systems. To be acceptable, each non-seismic Category I system should be designed to be isolated from any seismic Category I system by either a constraint or barrier, or should be remotely located with regard to the seismic Category I system. If it is not feasible or practical to isolate the seismic Category I system, adjacent non-seismic Category I systems should be analyzed according to the same seismic criteria