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:
vides guidelines on frequency content and stationarity. i. For NPPs that do not require an evaluation of an OBE, active mechanical equipment that has been qualified by testing should be qualified with five one-half SSE events 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 discussed in SECY-93-087. For other reactors, the staff will review the seismic qualification based on the OBE level in accordance with the design basis. 1.2.2 Specific NRC Staff Positions The NRC staff has the following specific positions on ASME QME-1-2017, Nonmandatory Appendix QR-A, including exceptions and clarifications: a. Section QR-A6200 (Seismic Qualification Requirements—Damping) The damping values used in analysis should be in accordance with the damping values for mechanical and electrical components listed in Table 6 of RG 1.61 or as approved in the plant design basis. b. Section QR-A6300 (Seismic Qualification Requirements—Required Response Spectrum) Section QR-A6300 states, “For in-line active mechanical equipment qualified in accordance with QR-A7400 [Earthquake Experience-Based Qualification], the RRS is typically the building filtered response spectrum at the distribution system support attachments to the building.” The use of the building-filtered response spectrum at the distribution system support attachments to the building as the RRS for the in-line equipment might be inadequate. The RRS for in-line active mechanical equipment should account for the potential motion amplification of the distribution system. c. Section QR-A7331 (Qualification by Similarity—Excitation) Section QR-A7331 states that “a conservative composite excitation may be generated by extrapolations or interpolations of data whose parameters are not