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:
In-place Functional Testing The instruments should have the capability for in-place functional testing. 4.3 Inaccessible Sensor Locations Instrumentation stations should be accessible for maintenance during full-power operation. Instrumentation that has sensors located in inaccessible areas should contain provisions for data recording in an accessible location, and the instrumentation should provide an external remote alarm to indicate actuation. The free-field instrumentation should be accessible immediately following an earthquake. 4.4 Pre- and Post-Event Recording Limits The instrumentation should record, at a minimum, 60 seconds of low-amplitude motion prior to seismic trigger actuation, continue to record the motion during the period in which the earthquake motion exceeds the seismic trigger threshold, and continue to record low-amplitude motion for a minimum of 60 seconds beyond the last exceedance of the seismic trigger threshold. 4.5 Recording Duration The instrumentation should be capable of recording a minimum of 120 minutes of sensed motion. 4.6 Battery Capacity The battery should be of sufficient capacity to power the instrumentation to sense and record a minimum of 2 hours (120 minutes) of motion over a period of not less than the channel check test interval (Section C. 9.2 of this guidance). This can be accomplished by providing enough battery capacity for a minimum of 2 hours of system operation at any time over a 4-days period in case of loss of normal power supply, without recharging, in combination with a battery charger whose line power is connected to an uninterruptable power supply or a line source with an alarm that is checked at least every 24 hours. Other combinations of larger battery capacity and alarm intervals may be used. 4.7 Reliability Instruments should be operating during all modes of operation; including periods of plant shutdown (see Section C.3 of this guidance). Instrument operational reliability should be demonstrated prior to