Document: NRC Regulatory Guide
Document ID: 37f53017-d71c-4f3c-a2a4-ab67a8270066
Document Type: regulatory_guide
Title: Pre-Earthquake Planning, Shutdown, and Restart of a Nuclear Power Plant Following an Earthquake (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1826/ML18268A185.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.166
CFR Part: 
CFR Title: 

Content:
nse spectra in a standard design approval or a certified design. certified standard design See “standard design certification.” free-field Those locations on the ground surface or in the site soil column that are sufficiently distant from the nuclear power plant structures to be essentially unaffected by the vibration of these structures. Therefore, a time-history recorder located at the free-field records essentially the free-field ground motion. ground motion response spectra Site-specific GMRS that are characterized by horizontal and vertical response spectra that are determined as free-field motions on the ground surface or as free-field outcrop motions on the uppermost in situ competent material. instrumental intensity Derived from ground motions recorded by seismographs. Unlike conventional intensity scales, the estimated intensities are not based directly on observations of earthquake effects on people or structures. An instrumental intensity map ranks the observed earthquake effect on a scale from I to X depending on the severity of shaking and provides a correlation to the potential damage, peak ground acceleration, and peak ground velocity. The U.S. Geological Survey produces these maps, which can be accessed at https://earthquake.usgs.gov/data/shakemap/. moment magnitude M The most common measure of earthquake size for medium to large earthquakes. The U.S. Geological Survey uses the moment magnitude scale M to report magnitudes for all modern earthquakes larger than M 4.0. operating-basis earthquake ground motion The vibratory ground motion for which those features of the nuclear power plant necessary for continued operation without undue risk to public health and safety will remain functional. The OBE is only associated with plant shutdown and inspection after an earthquake unless the applicant specifically selects it as a design input. response spectrum A plot of the maximum responses (acceleration, velocity, or displacement) of idealized