05000395/LER-2018-001, Valid Actuation of Emergency Diesel Generator

Valid Actuation of Emergency Diesel Generator

ML18078A066
Person / Time
Site:	Summer
Issue date:	03/19/2018
From:	Lippard G South Carolina Electric & Gas Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CR-18-00268, RC-18-0021 LER 2018-001-00
Download: ML18078A066 (4)

LER-2018-001, Valid Actuation of Emergency Diesel Generator

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)
3952018001R00 - NRC Website

text

A SCANA COMPANY George A. Lippard Vice President, Nuclear Operations 803.345.4810 March 19, 2018 Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555

Dear Sir / Madam:

Subject:

VIRGIL C. SUMMER NUCLEAR STATION (VCSNS), UNIT 1 DOCKET NO. 50-395 OPERATING LICENSE NO. NPF-12 LICENSEE EVENT REPORT (LER 2018-001-00)

VALID ACTUATION OF EMERGENCY DIESEL GENERATOR Attached is Licensee Event Report (LER) 2018-001-00, for the Virgil C. Summer Nuclear Station. This report describes the actuation of the A' Emergency Diesel Generator caused by the loss of the 115 kV power supply to the normal incoming Engineered Safety Features power supply to the safety related bus 1DA. This report is submitted in accordance with 10 CFR 50.73(a)(2)(iv)(A).

An apparent cause evaluation is being performed. A supplemental LER will be submitted to provide the results of the evaluation.

Should you have any questions, please call Mr. Michael S. Moore at (803)345-4752.

BAB/GAL/nk Attachment c:

J.E. Addison W.K. Kissam J. B. Archie J. H. Hamilton G. J. Lindamood W. M. Cherry C. Haney S. A. Williams NRC Resident Inspector L.W. Harris Paulette Ledbetter J.C. Mellette ICES Coordinator K.M. Sutton INPO Records Center Marsh USA, Inc.

Maintenance Rule Engineer NSRC RTS (CR-18-00268)

File (818.07)

PRSF (RC-18-0021)

V. C. Summer Nuclear Station

• P. 0. Box 88

• Jenkinsville, South Carolina

• 29065

• F (803) 941-9776

• www.sceg.com

NRC FORM 366 (04-2017)

U.S. NUCLEAR REGULATORY COMMISSION M

i LICENSEE EVENT REPORT (LER)

(See Page 2 for required number of digits/characters for each block)

(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/readina-rm/doc-collections/nuregs/staff/sr1022/r3A APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

1. FACILITY NAME V.C. Summer Nuclear Station, Unit 1

2. DOCKET NUMBER 05000 395

3. PAGE 1 OF

4. TITLE VALID ACTUATION OF EMERGENCY DIESEL GENERATOR

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED YEAR SEQUENTIAL NUMBER REV NO.

FACILITY NAME DOCKET NUMBER 05000 01 18 2018 2018 -

001 00 03 19 2018 FACILITY NAME DOCKET NUMBER 05000

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)

J 20.2201(b)

]

20.2203(a)(3)(i) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 1

[

20.2201(d)

]

20.2203(a)(3)(H) 50.73(a)(2)(H) (B) 50.73(a) (2)(viii)(B)

]

20.2203(a)(1)

]

20.2203(a)(4) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A)

]

20.2203(a)(2)(i) 50.36(c)(1)(i)(A)

[7] 50.73(a)(2)(iv)(A) 50.73(a)(2)(x)

10. POWER LEVEL

]

20.2203(a)(2)(H) 50.36(c)(1)(ii)(A) 50.73(a)(2)(v)(A) 73.71(a)(4)

]

20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(B) 73.71(a)(5)

] 20.2203(a)(2)(iv) 50.46(a)(3)(H) 50.73(a)(2)(v)(C) 73.77(a)(1) 100

] 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(D) 73.77(a)(2)(i)

^ 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(2) (vii) 73.77(a)(2)(H) 50.73(a)(2)(i)(C)

OTHER Specify in Abstract below or in =(04-2017)

U.S. NUCLEAR REGULATORY COMMISSION w

LICENSEE EVENT REPORT (LER)

I CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form http://wvwv.nrc.Qov/readina-rm/doc-collections/nureas/staff/sr1022/r3/1 APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020

, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

1.0 EVENT DESCRIPTION

On January 18, 2018 at 1202 [EST], VCSNS lost one of its two redundant offsite power supplies. The Parr Substation supplies the 115 kV offsite power supply to VCSNS. Emergent maintenance at the offsite Parr Substation resulted in an inadvertent opening of breaker #1802 in the Parr Switchyard. The loss of the power supply created an undervoltage condition on the normal incoming ESF power supply to the safety related bus 1DA. The 'A' EDG started and loads sequenced as designed.

The 'A' Residual Heat Removal Pump started but did not inject any water into the Reactor Coolant System. The 'A' Emergency Feedwater pump started and ran for approximately 2 minutes. All other plant equipment and systems also responded as expected. The normal power supply for the other required offsite power source remained available throughout the event.

Operations personnel monitored the plant and verified conditions were stable prior to realigning the plant to normal feed and securing the EDG. All loads were transferred back to the offsite power supply at 1318 [EST]. The EDG was secured at 1321 [EST], and reset for auto start.

2.0 EVENT ANALYSIS

The SCE&G transmission system supplies offsite power for operating the ESF buses as well as for startup and shutdown of the station. One power source is the SCE&G transmission grid terminating at the VCSNS 230 kV switchyard bus, which feeds the plant through a step down transformer. The second power source is from the offsite Parr Generating Complex over a 115 kV transmission line. This source is connected to the plant through onsite step down transformers and a separate regulating transformer.

The 7.2 kV ESF buses are each provided with three loss of voltage relays set at approximately 81% of the nominal bus voltage level and three degraded voltage relays set at approximately 91.34% of the nominal bus voltage level. Receipt of an undervoltage signal from the associated bus from either the loss of voltage relays or degraded voltage relays will automatically initiate a diesel generator start, a permissive for EFW turbine pump start, an ESF load sequence operation and a permissive for diesel generator circuit breaker close. Loss of voltage on an ESF bus opens the normal or alternate supply circuit breaker (whichever is closed) and, when emergency diesel generator voltage and frequency are established, closes the emergency power source circuit breaker.

The undervoltage and degraded voltage relays associated with 1DA functioned properly upon detecting the loss of voltage on the incoming 115kV line. The 'A' EDG started and all required loads sequenced on as designed. Operators acknowledged alarms and walked down the main control board to ensure equipment was functioning properly. The normal power supply for the other required offsite power source remained available throughout the event. Page 2

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