05000424/LER-2017-002

LER-2017-002, Vice President
Vogtle Units 1-2
7821 River RD
Waynesboro GA, 30830
706-848-0004 tel
706-848-3321 fax
June 29, 2017
Docket No: 50-424 NL-17-1104
U.S. Nuclear Regulatory Commission
ATTN: Document Control Desk
Washington, D.C. 20555-0001
Vogtle Electric Generating Plant — Unit 1
Licensee Event Report 2017-002-01
Wiring Error results in Automatic Actuation of a Safety System
Ladies and Gentlemen:
In accordance with the requirements of 10 CFR 50.73(a)(2)(iv)(A), Southern Nuclear Operating
Company is submitting the enclosed Licensee Event Report, 2017-002-01 for Vogtle Electric
Generating Plant Unit 1. This letter contains no NRC commitments. If you have any questions,
please contact Dom Sutton at (706) 848-1428.
Respectfully sub
Darin J. M rs
Vice President — Plant ogtle Units 1&2 - SNC
DJM/KCW
Enclosure: Unit 1 Licensee Event Report 2017-002-01
Cc: Regional Administrator
NRR Project Manager — Vogtle 1 & 2
Senior Resident Inspector — Vogtle 1 & 2
RType: CVC7000
Vogtle Electric Generating Plant — Unit 1
Licensee Event Report 2017-002-01
Wiring Labeling Error results in Automatic Actuation of a Safety System
Enclosure
Unit 1 Licensee Event Report 2017-002-01
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION
(04-2017)
LICENSEE EVENT REPORT (LER) ILWa t
l,viricir (See Page 2 for required number of digits/charactersfor each block)
•••••••
(See NUREG-1022, R.3 for instruction and guidance for completing this form
http://www.nrc.qovireadincl-rmidoc-collections/nuregs/staff/sr1022/r3i)
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 0313112020
Estimated burden per response to comply with this mandatory collection request: 80 hours
Reported lessons learned are incorporated into the licensing process and fed back to industry
Send comments regarding burden estimate to the Information Services Branch (T-2 F43), US
Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects
Resource@nrc gov, and to the Desk Officer, Office of Information •and Regulatory Affairs,
NEOB-10202, (3150-0104), Office of Management and Budget, Washington. DC 20503. If a means
used to impose an information collection does not display a currently valid OMB control number,
the NRC may not conduct or sponsor, and a person is not required to respond to, the information
collection.
1. FACILITY NAME
Vogtle Electric Generating Plant
. DOCKET NUMBER 13. PAGE
17.:15000424 1 1 OF 2
4. TITLE
Mirina Error results in_AulomaticActuation_of a Safety System_

Vogtle Electric Generating Plant
Event date:	3-17-2017
Report date:	6-29-2017
Reporting criterion:	10 CFR 50.73(a)(2)(iv)(B), System Actuation 10 CFR 50.73(a)(2)(iv)(A), System Actuation
4242017002R01 - NRC Website

LER 17-002-01 for Vogtle, Unit 1, Wiring Error Results in Automatic Actuation of a Safety System

ML17180A197
Person / Time
Site:	Vogtle
Issue date:	06/29/2017
From:	Myers D J Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-17-1104 LER 17-002-01
Download: ML17180A197 (4)

Infocollects Resource@nrc gov, and to the Desk Officer, Office of Information and Regulatory Affairs NEOB-10202 (3150-0104). Office of Management and Budget, Washington. DC 20503 If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor and a person is riot required to respond to the information collection.

A. Event Description

On March 17, 2017, at approximately 1517 EDT, Unit 1 was in refueling outage 1R20 with the unit in Mode 6 being prepared for fuel offload. After work had been performed on the 1-B Reserve Auxiliary Transformer (RAT) and during power restoration, a valid undervoltage actuation signal was sent to the 1-B Emergency Diesel Generator (EDG). The EDG started and automatically tied to the electrical safety bus. Once the issue was identified and understood by the operators, the EDG was secured and the electrical safety bus was transferred to the appropriate offsite power source.

The reactor was Mode 6 at the time of the event and remained so throughout the event. Decay heat was removed via the Residual Heat Removal (RHR) system, to the Component Cooling Water System, to the Nuclear Service Cooling Water system,. and finally to the atmosphere.

This report is required per 10CFR50.73(a)(2)(iv)(A) due to an automatic actuation of the Emergency AC power system.

B. Cause of Event

The cause of the event was a wiring error of the Open Phase system alarm and trip circuitry to the RAT. This resulted in a valid undervoltage actuation signal to be sent to the 1 B EDG as power was being restored to the Open Phase system. The EDG properly detected the undervoltage condition and responded per design.

C. Safety Assessment The EDG properly started and loaded the safety bus as required. At no time was decay heat removal lost to the RCS or the Spent Fuel Pool. Because all safety systems performed their safety function, the safety significance of the event is considered very low.

D. Corrective Actions

The wiring error was discovered using a continuity check during the post-event troubleshooting. The wires from the Open Phase system to the 1-B RAT were found mislabeled and landed on the wrong terminals. The wiring error was subsequently corrected and an extent of condition review was performed to verify proper labels and continuity and no other errors were found.

E. Previous Similar Events:

None -t-