ML12044A186

NRR E-mail Capture - Operating Experience Regarding Byron Loss-of-offsite-power Event - Duane Arnold Notification; Dominion Fleet Notification

ML12044A186
Person / Time
Site:	Byron
Issue date:	02/10/2012
From:	Feintuch K Division of Operating Reactor Licensing
To:	Browning T, Byrne T, Gadzala J, Sly C Dominion Generation, Florida Power & Light Co
References
Download: ML12044A186 (3)

Text

NRR-PMDAPEm Resource From: Feintuch, Karl Sent: Friday, February 10, 2012 1:50 PM To: Browning, Tony; Byrne, Thomas; Jack Gadzala; Craig D Sly Cc: Ring, Mark; Haeg, Lucas; Murray, Robert; Riemer, Kenneth; Krsek, Robert; Barclay, Kevin

Subject:

Operating Experience regarding Byron Loss-of-offsite-power event - Duane Arnold notification; Dominion Fleet notification Attachments: EN 7624 Byron 2.pdf A short time ago I distributed files to you pertaining to a Byron event. The attached file EN 7624 Byron 2.pdf replaces file EN 7624 Byron.pdf.

Please advise others to whom you distributed the original information.

1

Hearing Identifier: NRR_PMDA Email Number: 268 Mail Envelope Properties (4FFCA0F0F7657F428D1AF69C06EB598B0A7A453675)

Subject:

Operating Experience regarding Byron Loss-of-offsite-power event - Duane Arnold notification; Dominion Fleet notification Sent Date: 2/10/2012 1:49:48 PM Received Date: 2/10/2012 1:49:00 PM From: Feintuch, Karl Created By: Karl.Feintuch@nrc.gov Recipients:

"Ring, Mark" <Mark.Ring@nrc.gov>

Tracking Status: None "Haeg, Lucas" <Lucas.Haeg@nrc.gov>

Tracking Status: None "Murray, Robert" <Robert.Murray@nrc.gov>

Tracking Status: None "Riemer, Kenneth" <Kenneth.Riemer@nrc.gov>

Tracking Status: None "Krsek, Robert" <Robert.Krsek@nrc.gov>

Tracking Status: None "Barclay, Kevin" <Kevin.Barclay@nrc.gov>

Tracking Status: None "Browning, Tony" <Tony.Browning@fpl.com>

Tracking Status: None "Byrne, Thomas" <Thomas.Byrne@fpl.com>

Tracking Status: None "Jack Gadzala" <jack.gadzala@dom.com>

Tracking Status: None "Craig D Sly" <craig.d.sly@dom.com>

Tracking Status: None Post Office: HQCLSTR01.nrc.gov Files Size Date & Time MESSAGE 224 2/10/2012 1:49:00 PM EN 7624 Byron 2.pdf 92450 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received:

Power Reactor Event Number: 47624 Facility: BYRON Notification Date: 01/30/2012 Region: 3 State: IL Notification Time: 11:39 [ET]

Unit: [ ] [2] [ ] Event Date: 01/30/2012 RX Type: [1] W-4-LP,[2] W-4-LP Event Time: 10:01 [CST]

NRC Notified By: LEO WEHNER Last Update Date: 01/31/2012 HQ OPS Officer: JOHN KNOKE Emergency Class: UNUSUAL EVENT Person (Organization):

10 CFR Section: JAMNES CAMERON (R3DO) 50.72(a) (1) (i) - EMERGENCY DECLARED CYNTHIA PEDERSON (R3) 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL BRUCE BOGER (ET) 50.72(b)(2)(i) - PLANT S/D REQD BY TS JEFFERY GRANT (IRD) 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION SIL MOUVONE (DOE)

DEBBY HASSEL (DHS)

LOU BURCKANT (FEMA)

SAM WILLIS (HHS)

MIKE BEVERLY (USDA)

Initial RX Current Unit SCRAM Code RX CRIT Initial PWR Mode PWR Current RX Mode Power 2 A/R Y 100 0 Hot Standby Operation Event Text UNUSUAL EVENT DUE TO LOSS OF OFFSITE POWER GREATER THAN 15 MINUTES At 1101 EST, Byron Unit-2 experienced a reactor trip due to RCP undervoltage. All rods fully inserted, MSIV's were manually closed and decay heat is being removed by Auxiliary Feedwater pumps running and steam leaving via atmospheric relief valves. The unit is currently in a natural circulation cooldown with the diesels supplying station emergency loads. Licensee will be cooling the plant down to Mode 5.

At 1118 EST, Byron declared an Unusual Event due to a loss of offsite power on Unit 2 from a faulted Station Auxiliary Transformer (SAT). The faulted SAT caused both 6.9 kV and 4.1 kV bus voltage to drop. Smoke was observed coming from the SAT with no visible flames being apparent.

This caused bus loads to trip without a complete loss of ESF busses 241 and 242. These buses were manually disconnected from the SAT, which transferred the load to the emergency diesel generators 2A and 2B. Both diesel generators started and loaded without incident. Offsite assistance was requested from the local fire department as a precaution.

The licensee is also declaring notification for 10 CFR 50.72(b)(3)(v)(D)

Unit 1 is not being affected by this event and remains at 100% power.

The licensee has notified the NRC Resident Inspector.

• UPDATE FROM GREG BALESTRIERI TO JOHN KNOKE AT 2119 EST ON 01/31/12 * *

"At 2000 CST on 1/31/12, Byron terminated their Unusual Event due to the Loss of Offsite Power to Unit 2. Switchyard repairs were completed and offsite power has been restored to essential busses 241 and 242 thru System Auxiliary Transformers 242-1 and 242-2. Unit 2 Emergency Diesel Generators have been shutdown."

The licensee is citing classification 10 CFR 50.72(c)(1)(iii)

The licensee has notified the NRC Resident Inspector. Notified R3DO (James Cameron), NRR EO (Louise Lund), IRD MOC (Scott Morris), DHS (Konopka) and FEMA (Hollis). Licensee may issue a press release.