NRC Seismic Reevaluations

Seismic Reevaluations

Operating reactor sites are using present-day information to reevaluate the earthquake effects—or hazards—that could impact their site.  These newly reevaluated hazards, if worse than what the plant had originally calculated, will be analyzed to determine if plant structures, systems, and/or components need to be updated to protect against the new hazard.  The NRC will review each step in the analysis process and take action to require plant changes as necessary.
Process Overview
Related Documents:

• NRC Request for Information letter related to seismic, flooding and emergency preparedness (March 12, 2012)
• NRC-issued guidance for performing a Seismic Margin Assessment (JLD-ISG-2012-04) (November 16, 2012)
• Industry-issued guidance for screening, prioritization, and implementation details (SPID) (EPRI Report 1025287) (November 2012)
• NRC endorsement of guidance for screening, prioritization, and implementation details (SPID) (February 15, 2013)
• Industry-issued guidance on expedited approach for seismic reevaluations (EPRI Draft Report 3002000704) (April 2013)
• NRC endorsement of industry's expedited approach for seismic reevaluations (May 7, 2013)
• Industry letter on Relay Chatter Reviews for Seismic Hazard Screening (October 3, 2013)
• NRC letter to industry with guidance on the content of seismic reevaluation submittals (February 20, 2014)
• Industry-issued letter on seismic risk evaluations for plants in the Central and Eastern United States (CEUS) (March 12, 2014)
• NRC letter regarding Seismic Screening and Prioritization Results for CEUS Licensees (May 9, 2014)
• Probabilistic Seismic Hazard Analysis: Background Information (May 20, 2014)
• NRC memo providing preliminary staff ground motion response spectra for CEUS Licensees (May 21, 2014)
• NRC letter regarding development of Seismic Risk Evaluations (December 10, 2014)
• NRC response letter to licensees related to expedited approach commitment change (December 15, 2014)
• NRC letter regarding Seismic Screening and Prioritization Results for WUS Licensees (May 13, 2015)
• Industry-issued High Frequency Program Application Guidance and Schedule (July 30, 2015)
• NRC Endorsement of Industry High Frequency Program: Application Guidance (September 17, 2015)
• NRC letter on final determination regarding Seismic Probabilistic Risk Assessments (October 27, 2015)
• NRC letter regarding review of limited high frequency exceedance sites (February 18, 2016)
• Industry-issued Spent Fuel Pool Evaluation Guidance for Low to Moderate Hazard Sites (February 23, 2016)
• NRC endorsement of Spent Fuel Pool Evaluation Guidance for Low to Moderate Hazard Sites (March 17, 2016)

For plant-specific documents, visit our Plant-Specific Japan Lessons-Learned Activities page.