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:
valid OMB control number. 3.7.1-25 Revision 4 – December 2014 APPENDIX A TO SRP SECTION 3.7.1 GUIDANCE ON MINIMUM POWER SPECTRAL DENSITY FOR RG 1.60 DESIGN SPECTRA For a RG 1.60 horizontal response spectrum anchored to 1.0 g, the following guidance for developing minimum PSD can be used. For other peak accelerations, this PSD should be scaled by the square of the peak acceleration. The one-sided PSD is related to the Fourier amplitude |ܨሺ߱ሻ| of the time history by the equation ܵ௢ሺ߱ሻ = ଶ|ிሺఠሻ|మ ଶగ்ವ ...........................................................(1) In which ܶ஽ is the strong motion duration over which ܨሺ߱ሻ is evaluated; ߱ represents the circular frequency (in rad/s) and is defined as: ߱ൌ2ߨ݂, where ݂ is the natural frequency (in Hz). The duration ܶ஽ represents the duration of near maximum and nearly stationary power of an acceleration time history record. Additional guidance on estimation of ܶ஽ for artificial time history or actual earthquake time history is provided in Appendix B of NUREG/CR-5347. The average one-sided PSD defined by Equation (1) should exceed 80 percent of the target PSD as defined by Equation (2) for ݂ between 0.3 Hz and 24 Hz. Less than 2.5 Hz ܵ௢ሺ߱ሻ = 0.419 m 2/sec 3 ൬ቀ ఠ ଶగቁ/2.5 Hz ൰ ଴.ଶ 2.5 Hz to 9.0 Hz ܵ௢ሺ߱ሻ = 0.419 m 2/sec 3 ൬2.5 Hz/ ቀ ఠ ଶగቁ൰ ଵ.଼ ..................................................................(2) 9.0 Hz to 16.0 Hz ܵ௢ሺ߱ሻ = 418 cm 2/sec 3 ൬9.0 Hz/ ቀ ఠ ଶగቁ൰ ଷ Greater than 16 Hz ܵ௢ሺ߱ሻ = 74.2 cm 2/sec 3 ൬16.0 Hz/ ቀ ఠ ଶగቁ൰ ଼ At any frequency ݂ (where, ݂ൌ߱/2ߨ), the average PSD is computed over a frequency band width of ±20%, centered on the frequency ݂ (e.g., 4 Hz to 6 Hz band width for ݂ = 5 Hz). 3.7.1-26 Revision 4 – December 2014 The power above 24 Hz for the target PSD is so low as to be inconsequential so that checks above 24 Hz are unnecessary;