PNO-III-12-002: Difference between revisions
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# | {{Adams | ||
| number = ML12062A086 | |||
| issue date = 03/02/2012 | |||
| title = PNO-III-12-002A, (Update) Byron Unit 1 Loss of Offsite Power and Declaration of a Notice of Unusual Event | |||
| author name = Bartlett B, Duncan E | |||
| author affiliation = NRC/RGN-III/DRP/B3 | |||
| addressee name = | |||
| addressee affiliation = | |||
| docket = 05000454 | |||
| license number = NPF-037 | |||
| contact person = | |||
| document report number = PNO-III-12-002A | |||
| document type = NRC Preliminary Notification of Event/Occurrence | |||
| page count = 1 | |||
}} | |||
{{#Wiki_filter:PRELIMINARY NOTIFICATION - REGION III March 2, 2012 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE | |||
- PNO-III-12-002A | |||
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 by the Region III staff. | |||
Facility Byron Unit 1 Exelon Generation Company, LLC Byron, Illinois Docket: 50-454 License: NPF-37 Licensee Emergency Classification X Notification of Unusual Event Alert Site Area Emergency General Emergency Not Applicable | |||
==SUBJECT:== | |||
(UPDATE) BYRON UNIT 1 LOSS OF OFFSITE POWER AND DECLARATION OF A NOTICE OF UNUSUAL EVENT DESCRIPTION: | |||
This preliminary notification supplements information in PNO-III-12-002, which documented a loss of offsite power event for Byron Unit 1 and the resulting declaration of a Notice of Unusual Event (NOUE). | |||
At 5:31 p.m. (CST) on February 28, 2012, Byron Station declared a NOUE following a loss of offsite power that affected Byron Unit 1. The loss of offsite power caused both Unit 1 station auxiliary transformers (SATs) to de-energize. Once the loss of offsite power occurred, the emergency diesel generators automatically started as designed to supply power to safety-related equipment. The nonsafety-related loads automatically transferred to both Unit 1 unit auxiliary transformers and, as a result, Unit 1 remained operating at full power as designed. | |||
The licensee identified that a broken insulator in the switchyard was the direct cause of the problem. The licensee replaced the insulator and restored normal electrical lineup for the unit. As a result, Byron Unit 1 exited the NOUE at 9:00 p.m. (CST) on February 29, 2012. | |||
The NRC resident inspectors closely monitored the event and the licensee's assessment of the equipment problem and other aspects of this event. The inspectors observed the licensee's repair activities and normal electrical lineup restoration. | |||
State and local officials have been informed. | |||
The information presented herein has been discussed with the licensee, and is current as of 11:00 a.m. on March 1, 2012. | |||
ADAMS Accession Number ML12062A086. | |||
CONTACTS: Eric Duncan Bruce Bartlett 630-829-9620 815-234-5451 Eric.Duncan@nrc.gov Bruce.Bartlett@nrc.gov}} | |||
{{PNO-Nav|region=III}} | |||
Revision as of 21:36, 19 August 2019
| ML12062A086 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 03/02/2012 |
| From: | Bruce Bartlett, Eric Duncan Region 3 Branch 3 |
| To: | |
| References | |
| PNO-III-12-002A | |
| Download: ML12062A086 (1) | |
PRELIMINARY NOTIFICATION - REGION III March 2, 2012 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE
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 Byron Unit 1 Exelon Generation Company, LLC Byron, Illinois Docket: 50-454 License: NPF-37 Licensee Emergency Classification X Notification of Unusual Event Alert Site Area Emergency General Emergency Not Applicable
SUBJECT:
(UPDATE) BYRON UNIT 1 LOSS OF OFFSITE POWER AND DECLARATION OF A NOTICE OF UNUSUAL EVENT DESCRIPTION:
This preliminary notification supplements information in PNO-III-12-002, which documented a loss of offsite power event for Byron Unit 1 and the resulting declaration of a Notice of Unusual Event (NOUE).
At 5:31 p.m. (CST) on February 28, 2012, Byron Station declared a NOUE following a loss of offsite power that affected Byron Unit 1. The loss of offsite power caused both Unit 1 station auxiliary transformers (SATs) to de-energize. Once the loss of offsite power occurred, the emergency diesel generators automatically started as designed to supply power to safety-related equipment. The nonsafety-related loads automatically transferred to both Unit 1 unit auxiliary transformers and, as a result, Unit 1 remained operating at full power as designed.
The licensee identified that a broken insulator in the switchyard was the direct cause of the problem. The licensee replaced the insulator and restored normal electrical lineup for the unit. As a result, Byron Unit 1 exited the NOUE at 9:00 p.m. (CST) on February 29, 2012.
The NRC resident inspectors closely monitored the event and the licensee's assessment of the equipment problem and other aspects of this event. The inspectors observed the licensee's repair activities and normal electrical lineup restoration.
State and local officials have been informed.
The information presented herein has been discussed with the licensee, and is current as of 11:00 a.m. on March 1, 2012.
ADAMS Accession Number ML12062A086.
CONTACTS: Eric Duncan Bruce Bartlett 630-829-9620 815-234-5451 Eric.Duncan@nrc.gov Bruce.Bartlett@nrc.gov