Document: NUREG-0800
Document ID: 94da2f11-6df6-47d0-a25e-edeb21a4d649
Document Type: srp
Title: 3.7.1-12
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1419/ML14198A460.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.0
CFR Part: 
CFR Title: 

Content:
functions other than those given in Appendix A can be used if justified. For design response spectra other than RG 1.60 response spectra, a compatible target PSD should be generated. For generation of target PSD in such cases (i.e., spectra based on NUREG/CR-6728, “Technical Basis for Revision of Regulatory Guidance on Design Ground Motions: Hazard- and Risk-consistent Ground Motion Spectra Guidelines,” October 2001 or based on other spectra), the guidelines and procedures provided in Appendix B to this SRP section can be used. These guidelines and procedures are consistent with the approach described in NUREG/CR-5347, “Recommendations for Resolution of Public Comments, Seismic Design Criteria,” dated June 1989. Alternative methods for developing target spectra PSD can be used and are reviewed on a case-by-case basis. Regardless of the approach used, the development of the target PSD and the range of frequency for the PSD check are reviewed on a case-by- case basis. The PSD criteria are included as secondary check to prevent potential deficiency of power over the frequency range of interest. It should be noted that the ground motion is still primarily defined by the 3.7.1-13 Revision 4 – December 2014 design response spectrum. The use of PSD criteria alone can yield time histories that may not envelop the design response spectrum. ii. Approach 2. For Approach 2, the design ground motion time histories to match or envelop the design response spectra should be developed with Steps (a) through (d) below. The general objective is to generate a modified recorded or artificial accelerogram which achieves approximately mean based fit to the target response spectrum; that is, the average ratio of the spectral acceleration calculated from the accelerogram to the target, where the ratio is calculated frequency by frequency, is only slightly greater than “1.” The aim is to achieve an accelerogram that does not have significant gaps in the Fourier amplitude