PNO-III-20-002A, Update: Duane Arnold Energy Center, Notice of Unusual Event and Unplanned Shutdown Greater than 72 Hours Due to Loss of Offsite Power from Severe Weather Event; Decision to Permanently Shut Down

PNO-III-20-002A Update: Duane Arnold Energy Center, Notice of Unusual Event and Unplanned Shutdown Greater than 72 Hours Due to Loss of Offsite Power from Severe Weather Event; Decision to Permanently Shut Down

ML20267A144
Person / Time
Site:	Duane Arnold
Issue date:	09/22/2020
From:	April Nguyen, Robert Ruiz NRC/RGN-III
To:	NextEra Energy
References
PNO-III-20-002A
Download: ML20267A144 (1)

PRELIMINARY NOTIFICATION September 22, 2020 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE - PNO-III-20-002A This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. Some of the information may not yet be fully verified or evaluated and is essentially all that is known by the Region III staff on this date.

Facility Licensee Emergency Classification Duane Arnold Energy Center Notification of Unusual Event NextEra Energy, Inc. Alert Palo, IA Site Area Emergency Docket No: 50-331 General Emergency X Not Applicable

SUBJECT:

UPDATE: NOTICE OF UNUSUAL EVENT AND UNPLANNED SHUTDOWN GREATER THAN 72 HOURS DUE TO LOSS OF OFFSITE POWER FROM SEVERE WEATHER EVENT; DECISION TO PERMANENTLY SHUT DOWN On August 10, 2020, a severe weather event caused Duane Arnold Energy Center (DAEC) to lose offsite power, leading to an automatic reactor shutdown and declaration of a Notice of Unusual Event.

The emergency diesel generators successfully provided power to onsite essential equipment until offsite power was restored the following day. Offsite power has subsequently been restored to the site.

The NRC Senior Resident Inspector responded to the site and verified that required safety functions were maintained when the event occurred. In addition, other NRC inspectors from Region 3 assisted in monitoring licensee actions to restore offsite power and performed an independent assessment of licensees actions in response to the weather event.

The NRC evaluated the circumstances surrounding the event through the performance of focused baseline inspections, with technical support provided by Region 3 and Headquarters program office specialists, confirming that public health and safety was maintained throughout this event.

After NextEra Energy performed an assessment of the storm damage, they made the decision to permanently shut down DAEC ahead of the originally scheduled date of October 30, 2020. The plant is currently in Mode 4 (cold shutdown), with decommissioning activities underway.

This updated preliminary notification is issued for information only.

The State of Iowa has been notified.

The information presented herein has been discussed with the licensee and is current as of 12:45 CT, September 22, 2020.

ADAMS Accession Number: ML20267A144 Contacts: A. Nguyen R. Ruiz (630) 829-9587 (630) 829-9732 April.Nguyen@nrc.gov Robert.Ruiz@nrc.gov