Document: NRC Regulatory Guide
Document ID: 37f53017-d71c-4f3c-a2a4-ab67a8270066
Document Type: regulatory_guide
Title: Pre-Earthquake Planning, Shutdown, and Restart of a Nuclear Power Plant Following an Earthquake (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1826/ML18268A185.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.166
CFR Part: 
CFR Title: 

Content:
d EPRI NP-6695 and published it in 2013 as EPRI Report 3002000720, “Guidelines for Nuclear Plant Response to an Earthquake” (Ref. 13). In addition, experience has been gained from the shutdown and restart of the Virginia Electric and Power Company (VEPCO) North Anna Power Station following the August 23, 2011, earthquake in Mineral, Virginia. For example, the plant used older analogue recording instrumentation that took longer to process than modern digital instrumentation. This contributed to the delay in determining if the OBE and SSE were exceeded; in contrast, modern digital recording instrumentation would have facilitated the determination earlier. In response to the earthquake, VEPCO committed to a number of long-term actions to address exceeding the design basis as a result of the August 23, 2011, seismic event in a letter to the NRC dated November 7, 2011 (Ref. 14). NRC responded to the VEPCO letter with a Confirmatory Action Letter (CAL) on November 11, 2011 (Ref. 15), which remained in effect until NRC concluded that all the actions in the enclosure to the CAL were completed. ANSI/ANS-2.23-2016, incorporates the significant changes and additions included in EPRI Report 3002000720. ANSI/ANS-2.23-2016 provides guidance that implements both the observed damage level and earthquake shaking level to determine post-earthquake actions for an event that exceeds the OBE, whereas EPRI NP-6695 considers only the observed damage level to determine post-earthquake actions. In addition, ANSI/ANS-2.23-2016 builds on EPRI NP-6695 by adding guidance on action levels that clarify what actions should be taken, when they should be taken, and who should perform them. It also provides more comprehensive guidance than EPRI NP-6695 for short-term actions that a licensee should perform following an earthquake and for long-term post-earthquake evaluations. Therefore, this RG endorses ANSI/ANS-2.23-2016 and no longer endorses EPRI NP-6695. Harmonization with International