Document: NRC Regulatory Guide
Document ID: 99fe445b-c440-4921-ba8f-841c8f236046
Document Type: regulatory_guide
Title: Nuclear Power Plant Instrumentation for Earthquakes + HISTORY - HISTORY 09/2016 – DG-1332 , Proposed Revision 3 04/2015 – Periodic Review on Revision 2 – Revise 02/1995 – DG-1033, Third Proposed Revision 2 11/1992 – DG-1016, Second Proposed Revision 2 07/1981 – Draft MS 140-5 , First Proposed Revision 2 (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1610/ML16104A220.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.12
CFR Part: 
CFR Title: 

Content:
rrent regulatory practice, and consistent with applicable NRC requirements. DG-1332, Page 6 C. STAFF REGULATORY GUIDANCE This section provides detailed descriptions of the methods, approaches, or data that the staff considers acceptable for meeting the requirements for the type, locations, functionality, characteristics, installation, actuation, remote indication, accompanying materials, and maintenance of seismic instrumentation. The following regulatory positions satisfy the requirements in Paragraph (b) of Section 20.1101 to 10 CFR Part 20, Paragraph IV(a)(4) of Appendix S to 10 CFR Part 50, and Paragraph (d)(1) of 10 CFR 100.23, for ensuring the safety of nuclear power plants. 1. Seismic Instrumentation Type and Location 1.1 Scope Solid-state digital instrumentation that enable the processing of data at the plant site within 4 hours of the seismic event should be used. 1.2 Instrument Type and Location Triaxial acceleration sensors should be installed at the locations described below. (1) Free-field. (a) At the free ground surface, the location consistent with the site conditions and properties used to determine the site-specific ground motion response spectra (GMRS). (b) At a depth corresponding to the top of competent rock, or at foundation level if that is where the certified seismic design response spectra (CSDRS) and GMRS are defined if this depth exceeds 40 ft. below plant grade. (c) Placed at an appropriate distance away from structures, such that the free-field ground motion is recorded (see Section C.1.3.1 of this guidance). (d) Located so that (a) and (b) are as close to being directly over each other, as practical. (2) Containment foundation. (a) One three-component instrument when the foundation supports only containment and internal structures; or (b) Three three-component instruments when the foundation supports the containment/internal structure, and other Seismic Category I structures and forms a “nuclear island.” The instruments should be