Document: NRC Regulatory Guide
Document ID: cdc706d5-60ed-40a4-b55a-9771904107a7
Document Type: regulatory_guide
Title: Seismic Qualification of Electric and Mechanical Equipment for Nuclear Power Plants (Rev. 4)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1809/ML18093A675.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.100
CFR Part: 
CFR Title: 

Content:
simply restrict the frequency range of testing up to 33 hertz. The tested frequency range should be consistent with the RRS of the specific plant equipment. Different sections of this RG and IEEE Std 344-2013 refer to one-third-octave spacing for use with low-frequency excitation. For high-frequency sensitive equipment, an interval of one-sixth-octave spacing should be used, extending up to the frequency of interest shown in the RRS. f. For certain hard rock-based plants, the site-specific spectra might exceed the certified design spectra in the high-frequency range. As a result of the high-frequency ground motion, the seismic input to SSCs might also contain high-frequency excitations. Most existing seismic qualification tests used input frequencies up to only 33 hertz. The use of these prior test results should be justified by demonstrating that the frequency content of the PSD of the test waveform is sufficient in accordance with IEEE Std 344-2013, Annex B. g. If licensees or applicants plan new seismic qualification tests for equipment in plants with high-frequency ground motion, the tests should demonstrate the adequacy of the frequency content and the stationarity of the frequency content of the synthesized input waveforms. The frequency content of the Fourier transform of the test waveform or the frequency content of the PSD of the test waveform must be compatible with the amplified portion of the RRS. IEEE Std 344-2013, Annex B, provides acceptable guidelines on frequency content and stationarity. h. For NPPs that do require an evaluation of an OBE, electrical equipment that has been qualified by testing should be qualified with five events at one-half of the SSE followed by one full SSE event. Alternatively, the equipment may be qualified with a number of fractional peak cycles equivalent to the maximum peak cycles for five one-half SSE events, in accordance with IEEE Std 344-2013, Annex D, when such events are followed by one full SSE event. This is