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:
ether the OBE has been exceeded. The type, location, operating modes, characteristics, installation, activation, remote indication, and maintenance of the seismic instrumentation are described in this guide to help ensure (1) that the data DG-1332, Page 5 provided are comparable with the data used in the design of the nuclear power plant, (2) that exceedance of the OBE can be determined, and (3) that the equipment will perform as required. This guide does not address the need for instrumentation that would automatically scram a nuclear power plant when an earthquake occurs which exceeds a predetermined size. Also, this guide does not address nuclear power plant designs incorporating base isolation techniques since procedures for the seismic analysis and design are yet to be defined. It is important that all significant ground motion associated with an earthquake is recorded. This is accomplished by specifying how long before and after the actuation of the seismic trigger the data is recorded. Settings for the instrumentation's pre-event memory are correlated with the maximum distance to any potential epicenter that could affect a specific site. For example, the "P" wave may not be recorded when instrumentation is set for only a 3-second pre-event memory. Also, when an event occurs at some distance and the trigger threshold limit is not exceeded until 15 or 20 seconds into the event, a part of the record, although at low amplitude, is lost. A 60-second value may be more appropriate and is within the capabilities of current digital time-history accelerographs. Harmonization with International Standards The International Atomic Energy Agency (IAEA) has established a series of safety guides and standards constituting a high level of safety for protecting people and the environment. IAEA safety guides present international good practices and increasingly reflects best practices to help users striving to achieve high levels of safety. Pertinent to this regulatory guide,