ML12334A342

Official Exhibit - NYS000036-00-BD01 - Preliminary Notification of Event or Unusual Occurrence (PNO-III-11-015A), Monticello Nuclear Generating Plant, Unplanned Shutdown Greater than 72 Hours Due to a Loss of the Auxiliary Power Transformer

ML12334A342
Person / Time
Site:	Indian Point
Issue date:	10/28/2011
From:	Kenneth Riemer, Nirodh Shah NRC/RGN-III
To:	Atomic Safety and Licensing Board Panel
SECY RAS
References
RAS 21523, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01 PNO-III-11-015A
Download: ML12334A342 (1)

Text

United States Nuclear Regulatory Commission Official Hearing Exhibit In the Matter of

Entergy Nuclear Operations, Inc. (Indian Point Nuclear Generating Units 2 and 3)

ASLBP #:07-858-03-LR-BD01 Docket #:05000247 l 05000286 Exhibit #:

Identified:

Admitted: Withdrawn:

Rejected: Stricken: Other: NYS000036-00-BD01 10/15/2012 10/15/2012 NYS000036 Submitted: December 12, 2011 u .... 0 I./l I '

0-" ,-.* ..... PRELIMINARY NOTIFICATION

-REGION III October 28, 2011 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE

-PNO-III-11-015A 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 by the Region III staff. Facility Monticello Nuclear Generating Plant Northern States Power Co. Monticello, MN Docket: 50-263 License: DPR-22 Licensee Emergency Classification Notification of Unusual Event Alert _ Site Area Emergency

_ General Emergency

..x Not Applicable

SUBJECT:

UNPLANNED SHUTDOWN GREATER THAN 72 HOURS DUE TO A LOSS OF THE AUXILIARY POWER TRANSFORMER (UPDATE) DESCRIPTION:

On October 28,2011, at 5:32 a.m. Monticello restarted following a reactor scram occurring on October 21, 2011. The scram resulted from the unexpected loss of the auxiliary power transformer, which supplies offsite power to plant equipment.

There were also several unexpected equipment interactions that occurred during the event. The normal cooling water supply to one of the emergency diesel generators did not work properly and one of the non-safety electrical buses failed to energize.

These two conditions did not adversely impact the operation of any safety-related equipment and they were evaluated as part of the licensee's subsequent investigation.

There was no effect to public health and safety from this event. The NRC resident inspectors observed the reactor shutdown, the licensee repair and troubleshooting activities, and the subsequent restart. The resident inspectors have not identified any issues with the licensee's corrective actions. This preliminary notification is issued for information only. State and local officials have been informed.

The site issued a press release on October 21, 2011, describing the event. The information presented herein has been discussed with the licensee, and is current as of 9:00 a.m. (CST), on October 28,2011. ADAMS Accession Number ML11301A217 CONTACTS:

Ken Riemer 630/829-9628 Kenneth. Riemer@nrc.gov Nirodh Shah 630/829-9821 Nirodh.Shah@nrc.gov OAG10001404_00001