Document: NUREG-0800
Document ID: e40387bd-a6d6-49ae-a11b-6d22124df03a
Document Type: srp
Title: Each calculated spectrum of the artificial time history is considered to envelop the
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070317.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.0
CFR Part: 
CFR Title: 

Content:
Analysis Methods," American Society of Mechanical Engineers.72 S0( ) 2 F ( ) 2 2 TD 3.7.1-13 DRAFT Rev. 3 - April 1996 ....................(1) APPENDIX A TO SRP SECTION 3.7.1 SPECIFICATION FOR MINIMUM POWER SPECTRAL DENSITY (PSD) REQUIREMENT For a Regulatory Guide 1.60 horizontal response spectrum anchored to 1.0 g, the following minimum PSD requirement should be satisfied. For other peak accelerations, this PSD requirement should be scaled by the square of the peak acceleration. The onesided PSD is related to the Fourier amplitude |F( )| of the time history by the equation 73 where T is the strong motion duration over which F( ) is evaluated. This duration T D D represents the duration of near maximum and nearly stationary power of an acceleration time history record. Additional guidance on estimation of T for artificial time history or actual D earthquake time history is provided in Appendix B of NUREG/CR-5347 (Reference 610) . 74 The average onesided PSD defined by Equation (1) should exceed 80 percent of the target PSD as defined by Equation (2) from 0.3 Hz to 24 Hz. Less than 2.5 Hz S ( )(f) = 0.419 m 650 inch / sec (f/2.5 Hz ) 0 75 2 2 76 3 77 0.2 2.5 Hz to 9.0 Hz S ( )(f) = 0.419 m 650 inch / sec (2.5 Hz/f) .....................(2) O 2 2 78 3 1.8 9.0 Hz to 16.0 Hz S ( )(f) = 418 cm 64.8 inch /sec (9.0 Hz/f) O 2 2 3 3 Greater than 16 Hz S ( )(f) = 74.2 cm 11.5 inch /sec (16.0 Hz/f) O 2 2 3 8 At any frequency f, the average PSD is computed over a frequency band width of ±20 percent, centered on the frequency f (e.g., 4 Hz to 6 Hz band width for f = 5 Hz). The power above 24 Hz for the target PSD is so low as to be inconsequential so that checks above 24 Hz are unnecessary. (However, note that the response spectrum calculations are required beyond 24 Hz as governed by Regulatory Guide 1.60 definitions.) Similarly, power below 0.3 Hz has no influence on stiff nuclear plant facilities, so that checks below 0.3 Hz are DRAFT Rev. 3 - April 1996 3.7.1-14