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:
demonstrate that the seismic instrumentation will be operable during all modes of plant operation, including periods of plant shutdown. In addition, the applicant’s maintenance and repair procedures should provide for keeping the maximum number of instruments (i.e., the greatest number of instruments possible given the constraints of the system) in service during plant operation and shutdown. Instruments should be designed and installed so that the mounting is rigid and oriented so that the horizontal components are parallel to the orthogonal axes assumed for the seismic analysis. Also, protections against accidental impacts should be provided. With regard to capabilities and characteristics, the seismic instrumentation should include each of the specifications identified in RG 1.12, as well as any additional technical specifications listed here. This includes provisions for in-service testing, a remote alarm to indicate actuation, recording capabilities, sufficient dynamic range and sampling rate, and a low and adjustable actuating level or trigger. Both vertical and 3.7.4-5 Draft Revision 3 - August 2013 horizontal input vibratory ground motion should actuate the same time-history accelerograph. 2. Comparison with RG 1.166. The seismic instrumentation program is considered to be acceptable if it contains pre-earthquake planning and post-earthquake actions in accordance with RG 1.166. The bases for elements of the proposed seismic instrumentation program that differ from RG 1.166 must be provided. This guide provides guidance for a timely evaluation after an earthquake of the recorded seismic instrumentation data and for determining whether plant shutdown is required. The COL, DC, CP, and OL applicants should provide a description of both pre- earthquake planning 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