Document: NUREG-0800
Document ID: 71cb532b-b4ee-4e32-b83f-f1f4412193fb
Document Type: srp
Title: SEISMIC INSTRUMENTATION
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1230/ML12304A031.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.4
CFR Part: 
CFR Title: 

Content:
and post-earthquake actions in order to make a rapid determination of the degree of severity of the observed ground motion. The data from the seismic instrumentation, coupled with information obtained from a plant walkdown, should be used to make the initial determination of whether the plant must be shut down. With regard to the necessary baseline data, information related to seismic instrumentation, including instrument calibration, should be kept at the plant. The applicant’s program should also describe the necessary actions, such as selecting equipment and structures for inspections and the content of the baseline inspections that are to be taken immediately after an earthquake, as described in RG 1.166. If a free-field instrument is installed at a different location (e.g., elevation or geological profile) than the OBE is defined, the applicant should perform a site response analysis to develop a transfer function between the location at which the OBE is defined and the location of the instrument. This will enable an accurate comparison of the OBE spectrum and the response spectrum from the recorded vibratory ground motion. With regard to the evaluation of ground motion records, the applicant’s program should describe data identification (i.e., record collection log), data collection, and record evaluation procedures. Shutdown of the nuclear power plant is required if the vibratory ground motion experienced exceeds that of the OBE. A criterion for determining exceedance of the OBE is provided in the Electric Power Research Institute (EPRI) document EPRI NP-5930, “A Criterion for Determining Exceedance of the Operating Basis Earthquake.” This criterion is based on a threshold response spectrum ordinate check and a cumulative absolute velocity (CAV) check. The ground motion evaluation should consist of a check on the response spectrum and CAV and a check on the operability of the instrumentation as described in RG 1.166. This evaluation should take place