Text

(Vcsns), Unit 1 - Licensee Event Reports (2016-001-02, 2016-002-01, 2016-003-02) - Revision to Correct Typographical Errors
	ML18116A691
Person / Time
Site:	Summer
Issue date:	04/25/2018
From:	Lippard G; South Carolina Electric & Gas Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	RC-18-0056 LER 2016-001-02, LER 2016-002-01, LER 2016-003-02
	Download: ML18116A691 (16)
	v • d • e

George A. Lippard Vice President, Nuclear Operations 803.345.4810 SCE^SrG A SCANA COMPANY April 25, 2018 RC-18-0056 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 REPORTS (2016-001-02, 2016-002-01, 2016-003-02)

REVISIONS TO CORRECT TYPOGRAPHICAL ERRORS Attached are revised Licensee Event Reports (LER) 2016-001-02, 2016-002-01, and 2016-003-02, for the VCSNS Unit 1. These revised reports correct administrative typographical errors as follows:

LER 2016-001 NRC FORM 366, page 1 of 4, the Event Date in field 5 and the Sequential Number in field 6 have been revised to correct typographical errors. This revised report is submitted in accordance with 10 CFR 50.73(a)(2)(i)(B).

LER 2016-002 NRC FORM 366, page 1 of 3, the Manufacturer code in field 13 has been included. This revised report is submitted in accordance with 10 CFR 50.73(a)(2)(i)(B).

LER 2016-003 NRC FORM 366, page 1 of 4, the Docket Number in field 2 has been included and the Event Date in field 5 has been revised to correct a typographical error. This revised report is submitted in accordance with 10 CFR 50.73(a)(2)(v)(D).

These administrative typographical errors were captured in CR-18-00799.

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

Very truly yours WHK/GAL/bb V. C. Summer Nuclear Station

P. 0. Box 88

Jenkinsville, South Carolina

29065

F (803) 941-9776

www.sceg.com

Document Control Desk CR-18-00799 RC-18-0056 Page 2 of 2 Attachments Attachment I: LER 2016-001-02 Attachment II: LER 2016-002-01 Attachment III: LER 2016-003-02 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-18-00799)

File (818.07)

PRSF (RC-18-0056)

Document Control Desk Attachment I CR-18-00799 RC-18-0056 Page 1of 5 VIRGIL C. SUMMER NUCLEAR STATION (VCSNS)

DOCKET NO. 50-395 OPERATING LICENSE NO. NPF-12 ATTACHMENT I LER 2016-001-02

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (02-2018) Estimated burden per response to comply with this mandatory collection request 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months .

Reported lessons learned are incorporated into the licensing process and fed back to

&v^BEC% LICENSEE EVENT REPORT (LER) industry. Send comments regarding burden estimate to the Information Services Branch (1-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail

< S (iff \ ^a9e 2 f°r required number of digits/characters for each block) to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget,

^ ^ee NURE(3-1022, R.3 for instruction and guidance for completing this form Washington, DC 20503. If a means used to impose an information collection does not

\> ^ http://www.nrc.aov/readina-rm/doc-collections/nureas/staff/sr1022/r3/) 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 2. Docket Number 3. Page VC SUMMER-UNIT 1 05000 395 1 OF 4

4. Title LOW REFRIGERANT RENDERS A-CHILLER NON-FUNCTIONAL AND A CHARGING PUMP INOPERABLE

5. Event Date 6. LER Number 7. Report Date 8. Other Facilities Involved Y Sequential Rev Facility Name Docket Number Month Day Year Month Day Year r Number No. 05000 Facility Name Docket Number 12 16 2015 2016 - 001 - 02 04 25 2018 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)

] 20.2201(d) i ] 20.2203(a)(3)(ii)

50.73(a)(2)(ii)(B)

50.73(a)(2)(viii)(B) 1

] 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)

50.73(a)(2)(iv)(A)

50.73(a)(2)(x)

10. Power Level )) 20.2203(a)(2)(ii)

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) i" ] 20.2203(a)(2)(iv)

50.46(a)(3)(H)

50.73(a)(2)(v)(C)

73.77(a)(1) 100 l 20.2203(a)(2)(v)

50.73(a)(2)(i)(A)

50.73(a)(2)(v)(C)

73.77(a)(2)(ii)

] 20.2203(a)(2)(vi) l7] 50.73(a)(2)(i)(B)

50.73(a)(2)(vii)

73.77(a)(2)(iii)

50.73(a)(2)(i)(C) ] Other (Specify in Abstract below or in NRC Form 366A

12. Licensee Contact for this LER Licensee Contact Telephone Number (Include Area Code)

Michael S. Moore (803) 345-4752

13. Complete One Line for each Component Failure Described in this Report Cause System Component Manufacturer Reportable to ICES Cause System Component Manufacturer Reportable to ICES X KM CHU N418 Y

14. Supplemental Report Expected Month Day Year

15. Expected Submission Date l Yes (If yes, complete 15. Expected Submission Date) [/] No Abstract (Limit to 1400 spaces, i.e., approximately 14 single-spaced typewritten lines)

A past operability review determined that HVAC System Mechanical Water Chiller A (XHX0001A-VU) had been non-functional from July 24, 2015, through September 17, 2015, due to a refrigerant leak in Circuit 2. XVM16506A-VU, Chilled Water Chiller "A" Liquid Injection Solenoid Inlet Valve Circuit 2, was replaced and post maintenance testing completed satisfactorily.

On February 24, 2016, Operations started Circuit 2 of XHX0001A-VU to support the interim action and discovered an additional leakage path that is the cause of the initial event described in LER-2016-001-00. An inter-circuit evaporator gasket leak was allowing refrigerant leakage from Circuit 2 to Circuit 1. The gaskets were replaced and post maintenance testing was completed satisfactorily.

This report is being submitted in accordance with 10 CFR 50.73(a)(2)(i)(B).

NRC FORM 366 (02-2018)

NRC FORM 366A (04-2017) Page 2 of 4 NRC FORM 366A (04-2017) Page 3 of 4 NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2017)

Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months . Reported lessons learned are incorporated into the licensing process and fed back to industry. Send

° " LICENSEE EVENT REPORT (LER) comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to CONTINUATION SHEET lnfocollects.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 (See NUREG-1022, R.3 for instruction and guidance for completing this form 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 http://www.nrc.aov/readina-rm/doc-collections/nureas/staff/sr1022/r3A collection.

NARRATIVE 3.0 SAFETY SIGNIFICANCE (continued)

The delta CDF for the 57 day period out of service is 4.61E-08/yr The delta LERF for the 57 day period out of service is 5.82E-10/yr 4.0 PREVIOUS OCCURRENCE On October 24, 2011, a refrigerant leak on Circuit 1 of XHX0001A-VU was observed. The leak was identified as conning from XVR16482A-VU, Chilled Water Chiller "A" Condenser Vessel Relief Valve Circuit 1A. XVR16482A-VU was reinstalled with new sealant and a follow up leak check was completed satisfactorily.

5.0 CORRECTIVE ACTIONS For the refrigerant leak around the threaded connection of XVM16506A-VU, Chilled Water Chiller "A" Liquid Injection Solenoid Inlet Valve Circuit 2, XVM16506-VU was replaced.

The gaskets were replaced on the north and south side of the evaporator per maintenance procedures. Post maintenance testing was conducted satisfactory to ensure the inter circuit leak was resolved.

NRC FORM 366A (04-2017) Page 4 of 4

Document Control Desk Attachment II CR-18-00799 RC-18-0056 Page 1 of 4 VIRGIL C. SUMMER NUCLEAR STATION (VCSNS)

DOCKET NO. 50-395 OPERATING LICENSE NO. NPF-12 ATTACHMENT II LER 2016-002-01

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (02-2018) Estimated burden per response to comply with this mandatory collection request 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months .

Reported lessons learned are incorporated into the licensing process and fed back to LICENSEE EVENT REPORT (LER) industry. Send comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail i ?? \ ^ee Pa9e 2 for required number of digits/characters for each block) to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget

/ (See NUREG-1022, R.3 for instruction and guidance for completing this form Washington, DC 20503. If a means used to impose an information collection does not

^ J1 http://www.nrc.aov/readina-rm/doc-collections/nureas/staff/sr1022/r3/) display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is notrequired to respond to, the information collection.

1. Facility Name 2. Docket Number 3. Page VC SUMMER-UNIT 1 05000 395 1 OF 3

4. Title PRESSURIZER HEATER INOPERABLE LONGER THAN TECHNICAL SPECIFICATION LIMITING CONDITION FOR OPERATION 3.4.3

5. Event Date 6. LER Number 7. Report Date 8. Other Facilities Involved Y Sequential Rev Facility Name Docket Number Month Day Year Month Day Year Number No. 05000 Facility Name Docket Number 07 22 2016 2016 - 002 - 01 04 25 2018 05000

9. Operating Mode 11. This Report is Submitted Pursuant to the Requirements of 10 CFR §: (Check all that apply) 20.2201 (b)

20.2203(a)(3)(i)

50.73(a)(2)(ii)(A)

50.73(a)(2)(viii)(A) 20.2201 (d) 20.2203(a)(3)(H)

50.73(a)(2)(ii)(B)

50.73(a)(2)(viii)(B) 1

] 20.2203(a)(1) l [ 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)

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)

J 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)(C)

73.77(a)(2)(H)

] 20.2203(a)(2)(vi) \7\ 50.73(a)(2)(i)(B)

50.73(a)(2)(vii)

73.77(a)(2)(iii)

50.73(a)(2)(i)(C) J Other (Specify in Abstract below or in NRC Form 366A

12. Licensee Contact for this LER Licensee Contact Telephone Number (Include Area Code)

Michael S. Moore (803) 345-4752

13. Complete One Line for each Component Failure Described in this Report Cause System Component Manufacturer Reportable to ICES Cause System Component Manufacturer Reportable to ICES E AB EHTR, 52 G080 Y

14. Supplemental Report Expected Month Day Year

15. Expected Submission Date l [ Yes (If yes, complete 15. Expected Submission Date) [/] No Abstract (Limit to 1400 spaces, i.e., approximately 14 single-spaced typewritten lines)

On July 22, 2016, a past operability review determined that the Pressurizer Backup Group 2 Heaters were inoperable for 94 hours0.00109 days 0.0261 hours 1.554233e-4 weeks 3.5767e-5 months , from 0600 on June 15, 2016, to 0400 on June 19, 2016. On June 18, 2016, the breaker (XSW1DB 05) that provides safety class 1E power to Pressurizer Backup Group 2 Heaters was found with its charging springs discharged. The closing coil plunger was found mechanically bound due to foreign material. The closing latch was unable to reset and the contacts did not allow the spring charging motor to energize and recharge the closing springs. The failed breaker XSW1DB 05 was swapped with a spare breaker and the Pressurizer Backup Group 2 Heaters were returned to service at 0400, June 19, 2016.

The time for which the Pressurizer Backup Group 2 Heaters were inoperable exceeds Technical Specification 3.4.3.a Limiting Condition for Operation of 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . Therefore, this report is being submitted in accordance with 10 CFR 50.73(a)(2)(i)(B).

NRC FORM 366 (02-2018)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2017)

Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months . Reported lessons learned are incorporated into the licensing process and fed back to industry. Send LICENSEE EVENT REPORT (LER) comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to CONTINUATION SHEET lnfocollects.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 (See NUREG-1022, R.3 for instruction and guidance for completing this form used to impose an information collection does not display a currently valid OMB control number, the http://www.nrc.gov/readina-rm/doc-collections/nureas/staff/sr1022/r3A NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

2. DOCKET NUMBER 3. LER NUMBER

1. FACILITY NAME YEAR SEQUENTIAL REV NUMBER NO.

VC SUMMER-UNIT 1 05000- 395 2016 - 002 - 01 NARRATIVE 1.0 EVENT DESCRIPTION On June 18, 2016, breaker XSW1DB 05 was found with charging springs discharged. The closing coil plunger was found mechanically bound in the up position. The closing latch was unable to reset and the contacts did not allow the spring charging motor to energize and recharge the closing springs.

A past operability evaluation, completed on July 22, 2016, determined that the breaker was not reliable for 94 hours0.00109 days 0.0261 hours 1.554233e-4 weeks 3.5767e-5 months from 0600 on June 15, 2016, to 0400, June 19, 2016. This event exceeded the Technical Specification (TS) 3.4.3.a Limiting Condition for Operation (LCO) of 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

2.0 EVENT ANALYSIS TS 3.4.3 requires a water volume less than or equal to 1288 cubic feet and at least two groups of pressurizer heaters, each having a capacity of at least 125 kW, to be operable during Modes 1, 2, and 3. The requirement that a minimum number of pressurizer heaters be operable enhances the capability of the plant to control Reactor Coolant System pressure and establish natural circulation. Pressurizer pressure is controlled by three components: electrical heaters, spray valves, and relief valves. The electrical heaters are energized when pressurizer pressure drops below a desired pressure. When the desired pressure is reached, the heaters are turned off.

The 78 pressurizer heaters have an installed capacity of 1420 kW which is divided between one control group and two backup groups. Proportional (Variable) Heaters are powered from bus 1C (XSW1C 02), Backup Group 1 is powered from XSW1DA (XSW1DA 12) and Backup Group 2 is powered from XSW1DB (XSW1DB 05). The two backup heater groups are on separate emergency generator supplied buses so that any single failure will not defeat operation or control of both groups. Additionally, the two backup heaters have automatic actions from the pressurizer level control. The Proportional (Variable) Heaters are supplied by non-safety power, thus the TS requirement refers only to the backup groups of pressurizer heaters. With one group of pressurizer heaters unavailable, two groups must be restored to operable status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , or be in at least hot standby within the next six hours and in hot shutdown within the following six hours.

On June 18, 2016 breaker XSW1 DB 05 was found with its charging springs discharged. The closing coil plunger was found mechanically bound in the up position. The closing latch was unable to reset and the contacts didn't allow the spring charging motor to energize and recharge the closing springs. The station replaced the breaker with a spare, completed the breaker retest, and cleared the R&R.

Station investigation of the failed breaker revealed foreign material was causing the plunger to stick. The foreign material was determined to be part of the cotter pin that was introduced during the refurbishment of the breaker conducted under a previous work order. The piece of cotter pin caused the plunger to fail after the coil was actuated.

NRC FORM 366A (04-2017) Page 2 of 3

NRC FORM 366A (04-2017) Page 3 of 3 Document Control Desk Attachment III CR-18-00799 RC-18-0056 Page 1of 5 VIRGIL C. SUMMER NUCLEAR STATION (VCSNS)

DOCKET NO. 50-395 OPERATING LICENSE NO. NPF-12 ATTACHMENT III LER 2016-003-02

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018) Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months .

Reported lessons learned are incorporated into the licensing process and fed back to LICENSEE EVENT REPORT (LER) industry. Send comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail

< S (fit' S ^ee Page 2 for required number of digits/characters for each block) to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget,

£ (See NUREG-1022, R.3 for instruction and guidance for completing this form Washington, DC 20503. If a means used to impose an information collection does not

\ ^ *<? http://www.nrc.aov/readina-rm/doc-collections/nureas/staff/sr1022/r3/) display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is notrequired to respond to, the information collection.

1. Facility Name 2. Docket Number 3. Page VC SUMMER-UNIT 1 05000 395 1 OF 4

4. Title STEAM PROPAGATION DOOR DISCOVERED PROPPED OPEN

5. Event Date 6. LER Number 7. Report Date 8. Other Facilities Involved Y Sequential Rev Facility Name Docket Number Month Day Year Month Day Year r Number No. 05000 Facility Name Docket Number 09 13 2016 2016 - 003 - 02 04 25 2018 05000

9. Operating Mode 11. This Report is Submitted Pursuant to the Requirements of 10 CFR §: (Check all that apply) 20.2201(b) 20.2203(a)(3)(i)

50.73(a)(2)(ii)(A)

50.73(a)(2)(viii)(A) 3 20.2201(d) 3 20.2203(a)(3)(ii)

50.73(a)(2)(ii)(B)

50.73(a)(2)(viii)(B) 1

] 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)

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)(ii)

50.73(a)(2)(v)(C)

73.77(a)(1) 100 ] 20.2203(a)(2)(v)

50.73(a)(2)(i)(A) \7\ 50.73(a)(2)(v)(D)

73.77(a)(2)©

] 20.2203(a)(2)(vi)

50.73(a)(2)(i)(B)

50.73(a)(2)(vii)

73.77(a)(2)(ii)

50.73(a)(2)(i)(C) \7\ Other (Specify in Abstract below or in NRC Form 366A)

12. Licensee Contact for this LER Licensee Contact Telephone Number (Include Area Code)

Michael S. Moore (803) 345-4752

13. Complete One Line for each Component Failure Described in this Report Cause System Component Manufacturer Reportable to ICES Cause System Component Manufacturer Reportable to ICES A KM CHU Y018 Y

14. Supplemental Report Expected Month Day Year

15. Expected Submission Date

] Yes (If yes, complete 15. Expected Submission Date) [/] No Abstract (Limit to 1400 spaces, i.e., approximately 14 single-spaced typewritten lines)

On September 13, 2016 at 20:30 a steam propagation door (DRIB/107) to Chiller Room C was discovered propped open without all required compensatory actions during routine operator rounds. The door was determined to be open for approximately 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months and 22 minutes. The propped open door could have rendered both trains of Chilled Water nonfunctional if a High Energy Line Break (HELB) event occurred. This could have subsequently rendered both trains of High Head Safety Injection inoperable due to the loss of chilled water cooling to safety related room coolers. Technical Specification 3.0.3 was entered until the door was secured at 20:42. The cause of the event was due to a human performance error. Station Shift Test Specialist authorized the door to be propped open without verifying programmatic contingencies were established. This condition is reportable under 10CFR50.72(b)(3)(v) and 10CFR50.73(a)(2)(v)(D) as any event or condition that at the time of discovery could have prevented the fulfillment of a safety function. An 8 hour9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months event notification (EN 52240) was made.

VCSNS has supplemented the previous License Event Report with the Final Results from an Engineering Technical Report. The report concludes that a HELB event postulated to occur during the times when the non-conforming HELB barrier configuration existed would not have impacted the operability of equipment in the Battery/Battery Charger Rooms or the functionality of equipment in the Chiller Pump Room and at least one of the three Chiller Rooms.

NRC FORM 366 (04-2018)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)

Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months . Reported LICENSEE EVENT REPORT (LER) 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), U. S. Nuclear Regulatory

, CONTINUATION SHEET Commission, Washington, DC 20555-0001, or by e-mail to lnfocollects.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 (See NUREG-1022, R.3 for instruction and guidance for completing this form collection does not display a currently valid OMB control number, the NRC may not conduct or http://www.nrc.aov/readina-rm/doc-collections/nuregs/staff/sr1022/r3/f sponsor, and a person is not required to respond to, the information collection.

1. FACILITY NAME 2. DOCKET NUMBER 3. LER NUMBER YEAR SEQUENTIAL REV NUMBER NO.

VC SUMMER-UNIT 1 05000- 395 2016 - 003 - 02 NARRATIVE 1.0 EVENT DESCRIPTION On September 13, 2016 at 20:30 a steam propagation door (DRIB/107) to Chiller Room C was discovered propped open without all required compensatory actions during routine operator rounds. The door was determined to be open for approximately 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months and 22 minutes. The propped open door could have rendered both trains of Chilled Water (VU) nonfunctional if a High Energy Line Break (HELB) event occurred. This could have subsequently rendered both trains of High Head Safety Injection inoperable due to the loss of chilled water cooling to safety related room coolers. Technical Specification 3.0.3 was entered until the door was secured at 20:42.

2.0 EVENT ANALYSIS The Fire Protection Procedure (FPP-025 Enclosure 6.3) provides the compensatory actions for propping open DRIB/107.

Door DRIB/107 may be opened during all Modes provided XHX0001C-VU is declared nonfunctional and train separation has been established via closure of HELB dampers. Closure of the HELB dampers isolates the room from the common ventilation ductwork supplying the other rooms. This contingency is controlled by the station's procedure for controlling fire barriers and the Lock-Out/Tag-Out (LOTO) process. DRIB/107 is a steam propagation door that leads to one of three chiller units that provide chilled water to the VU System. The VU System has two trains and is designed to provide safety related cooling to various areas and equipment as discussed in FSAR 9.4.7.2.4. Allowing the steam propagation door to Chiller Room C to be propped open without closing the room's HELB dampers would have provided a pathway for a steam environment to the other chiller rooms if a HELB event occurred. High Energy Line Breaks are discussed in FSAR 3.11.2.2.2.2 and 15.4.2. The open pathway could have affected the functionality of both trains of VU. In addition, the ventilation for the chiller rooms shares common supply and exhaust ductwork with the Safety Related Battery and Charger Room Ventilation system, thereby providing a potential pathway for a steam environment to also affect the functionality of both trains of vital DC power systems.

The apparent cause of this event was a human performance error. Compensatory measures associated with propping open DRIB/107 had been in place during the previous night shift and were cleared prior to the end of the night shift. There was inadequate communication between Work Control and the Shift Test Specialist that the LOTO for a HELB contingency had been cleared. The Shift Test Specialist assumed the HELB contingencies were still in place when a subsequent request to prop open the door was made.

The VU System provides cooling to safety related areas (TS Table 3.7-7) as an attendant cooling system and supports the comfort requirements for the Control Room Emergency Filtration Systems (CREFS). The VU System is needed to ensure that equipment located within these areas can withstand the environmental effects of a postulated FSAR Chapter 15 event. With a nonfunctional chiller unit, its associated VU train will become nonfunctional, thereby affecting room temperatures and the reliability of the train's associated equipment. The most limiting area for temperature limits has been identified as the Charging Pump rooms. PerTS 3/4.5.2, one Charging Pump has to be operable per train of Emergency Core Cooling System (ECCS) during Modes 1-3.

TS 3/4.7.6, "Control Room Emergency Filtration Systems (CREFS)", states that two CREFS trains shall be operable. The surveillance requirements under TS 3/4.7.6 require each CREFS train to be demonstrated operable through verification that the control room air temperature is less than or equal to 85 degrees Fahrenheit.

NRC FORM 366A (04-2018)

Page 2 of 4

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)

Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months . Reported LICENSEE EVENT REPORT (LER) 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), U. S. Nuclear Regulatory CONTINUATION SHEET Commission, Washington, DC 20555-0001, or by e-mail to lnfocollects.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 (See NUREG-1022, R.3 for instruction and guidance for completing this form collection does not display a currently valid OMB control number, the NRC may not conduct or http://www.nrc.aov/readina-rm/doc-collections/nureas/staff/sr1022/r3/) sponsor, and a person is not required to respond to, the information collection.

1. FACILITY NAME 2. DOCKET NUMBER 3. LER NUMBER YEAR SEQUENTIAL REV NUMBER VC SUMMER-UNIT 1 05000- NO.

2016 003 02 NARRATIVE TS 3/4.7.9, "Area Temperature Monitoring", and associated Table 3.7-7 describe the area temperature limits during normal operation due to cooling provided by the VU System. If the chiller cooling a Chilled Water loop is not running, room temperatures will rise over time. If the temperature in a given area exceeds the limit shown in TS Table 3.7-7 for eight hours, a Special Report detailing the basis for continued operability must be submitted to the NRC within 30 days.

Additionally, if the Technical Specification limit for a given area is exceeded by thirty degrees for four hours, the equipment in the associated area must be declared inoperable.

TS 3/4.8.2 "D.C. SOURCES", the D.C. power sources and associated distribution systems during operation ensures that sufficient power will be available to supply the safety related equipment required for 1) the safe shutdown of the facility and 2) the mitigation and control of accident conditions within the facility. The minimum specified independent and redundant D.C. power sources and distribution systems satisfy the requirements of General Design Criterion 17 of Appendix "A" to 10 CFR 50.

VCSNS contracted an engineering firm to conduct an assessment of the impact on equipment affected by this condition.

Specifically, this evaluation considers DRIB/107 being propped open while the associated room's ventilation system HELB dampers remained open. HELB dampers are installed to prevent steam propagation from the Intermediate Building (IB)

Harsh Area into the Chiller Rooms, Chilled Water Pump Room, Battery Rooms, and the Battery Charger Rooms (Mild Areas) during postulated HELB events when the affected chiller room door is propped open. The evaluation also considers the nonconforming condition of the Chiller Room and Chilled Water Pump Room drain system that was discovered under the extent of condition review. Specifically, steam propagation barriers (orifices) in the floor drainage system were installed incorrectly between the Chiller Rooms and the Chilled Water Pump Room. While this condition existed, Chiller Rooms B and C were connected by an 8-inch drain line, as were Chiller Room A and the Chilled Water Pump Room. The drainage system nonconformance condition will be reported in LER-2016-004.

A thermal hydraulic model was developed using the GOTHIC computer code (version 8.1) to calculate the environmental conditions that could have existed at the Intermediate Building (IB) 412 foot elevation during a postulated HELB event.

The GOTHIC computer program is a general purpose analysis tool that solves the conservation equations for mass, energy, and momentum for multi-component, multi-phase flow, and it has been used extensively for compartment transient analysis in nuclear power plants. The initial analysis indicated that during a postulated HELB event, the environmental result for the additional rooms connected by the drain line were not expected to significantly rise in temperature and humidity. And as a result, there would have been reasonable assurance that the risk significant equipment in the Mild Area (i.e., Chiller, Chiller Pump, Battery and Battery Charger rooms) would have been able to perform their required functions had such an event occurred.

However, further analyses were initiated to ensure smaller break sizes (<4" Nominal Pipe Size (NPS)) would not potentially lead to more steam propagation than the EQ design basis cases. The station performed analyses which postulated these types of breaks. For small breaks, the mass and energy release rates are low and the IB rooftop blowout panels do not actuate. Although temperatures within the IB rise, IB pressure remains low, so that propagation of air/steam from the IB is small. As a result, entry of air/steam from the IB into Chiller Room C does not lead to significant changes in the Battery, Battery Charger, Chiller, and Chilled Water Pump room conditions.

NRC FORM 366A (04-2018)

Page 3 of 4

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)

Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months . Reported LICENSEE EVENT REPORT (LER) 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), U. S. Nuclear Regulatory CONTINUATION SHEET Commission, Washington, DC 20555-0001, or by e-mail to lnfocollects.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 (See NUREG-1022, R.3 for instruction and guidance for completing this form collection does not display a currently valid OMB control number, the NRC may not conduct or http://www.nrc.aov/readina-rm/doc-collections/nureas/staff/sr1022/r3/') sponsor, and a person is not required to respond to, the information collection.

1. FACILITY NAME 2. DOCKET NUMBER 3. LER NUMBER YEAR SEQUENTIAL REV NUMBER NO.

VC SUMMER-UNIT 1 05000-2016 003 02 NARRATIVE For intermediate breaks, the mass and energy release rates could be high enough to result in degraded conditions at an open Chiller Room door, but low enough to not actuate the IB rooftop blowout panels. As a result, intermediate breaks have the potential to produce the largest changes in Battery/Battery Charger and Chiller Area room environmental conditions. However, for this worst case, the Battery/Battery Charger Area room temperatures remain in their normal operational band and relative humidity remains at normal values. Chiller Room A temperature remains in the normal operational band and relative humidity remains at normal values. The Chiller Pump Room temperature remains in the normal operational band and relative humidity remains at normal values because it is not connected via floor drains to the Chiller Room with the propped open door. The environmental conditions in Chiller Room B, however, would degrade to the point where Chiller B would fail due to high temperature resulting in one of the two trains of Chilled Water being inoperable during the time the door to Chiller Room C was propped open. Chiller Room A and the Chilled Water Pump Rooms would not have been affected by the postulated event.

3.0 SAFETY SIGNIFICANCE A HELB event postulated to occur during the times when the non-conforming HELB barrier configuration existed would not have impacted the functionality of equipment in the Battery/Battery Charger Rooms (which would have remained within Technical Specification 3.7.9 limits) or the functionality of equipment in Chiller Room A and the Chilled Water Pump Rooms. There is no change to the result in the PRA model, and the condition is determined to be not risk significant.

4.0 PREVIOUS OCCURRENCE No previous occurrence within the last three years.

5.0 CORRECTIVE ACTIONS To mitigate the events and preclude reoccurrence VCSNS conducted the following activities:

1. The door was closed as the immediate action and VCSNS issued Special Order 16-05 as an interim action to suspend propping open chiller room doors. This Special Order has since been cancelled as the proper plant configuration (drain orifices) has been restored to its normal configuration.

2. The station conducted a walkdown of the steam barriers associated with the event. Based on the walkdown the station evaluated the extent of condition of identified nonconformances addressed in LER 2016-004-00 (orifice) and LER 2016-005-00 (ductwork). A detailed analysis was completed to address safety significance.

3. Procedures have been reviewed and updated to minimize reoccurrence under the Corrective Action Program.

4. The station initiated an assessment of the potential impacts due to steam propagation. The resulting technical report documents the evaluation of the potential impact on equipment functionality of recently identified non-conforming HELB barrier configurations at VCSNS.

NRC FORM 366A (04-2018)

Page 4 of 4

George A. Lippard Vice President, Nuclear Operations 803.345.4810 SCE^SrG A SCANA COMPANY April 25, 2018 RC-18-0056 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 REPORTS (2016-001-02, 2016-002-01, 2016-003-02)

REVISIONS TO CORRECT TYPOGRAPHICAL ERRORS Attached are revised Licensee Event Reports (LER) 2016-001-02, 2016-002-01, and 2016-003-02, for the VCSNS Unit 1. These revised reports correct administrative typographical errors as follows:

LER 2016-001 NRC FORM 366, page 1 of 4, the Event Date in field 5 and the Sequential Number in field 6 have been revised to correct typographical errors. This revised report is submitted in accordance with 10 CFR 50.73(a)(2)(i)(B).

LER 2016-002 NRC FORM 366, page 1 of 3, the Manufacturer code in field 13 has been included. This revised report is submitted in accordance with 10 CFR 50.73(a)(2)(i)(B).

LER 2016-003 NRC FORM 366, page 1 of 4, the Docket Number in field 2 has been included and the Event Date in field 5 has been revised to correct a typographical error. This revised report is submitted in accordance with 10 CFR 50.73(a)(2)(v)(D).

These administrative typographical errors were captured in CR-18-00799.

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

Very truly yours WHK/GAL/bb V. C. Summer Nuclear Station

P. 0. Box 88

Jenkinsville, South Carolina

29065

F (803) 941-9776

www.sceg.com

Document Control Desk CR-18-00799 RC-18-0056 Page 2 of 2 Attachments Attachment I: LER 2016-001-02 Attachment II: LER 2016-002-01 Attachment III: LER 2016-003-02 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-18-00799)

File (818.07)

PRSF (RC-18-0056)

Document Control Desk Attachment I CR-18-00799 RC-18-0056 Page 1of 5 VIRGIL C. SUMMER NUCLEAR STATION (VCSNS)

DOCKET NO. 50-395 OPERATING LICENSE NO. NPF-12 ATTACHMENT I LER 2016-001-02

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (02-2018) Estimated burden per response to comply with this mandatory collection request 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months .

Reported lessons learned are incorporated into the licensing process and fed back to

&v^BEC% LICENSEE EVENT REPORT (LER) industry. Send comments regarding burden estimate to the Information Services Branch (1-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail

< S (iff \ ^a9e 2 f°r required number of digits/characters for each block) to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget,

^ ^ee NURE(3-1022, R.3 for instruction and guidance for completing this form Washington, DC 20503. If a means used to impose an information collection does not

\> ^ http://www.nrc.aov/readina-rm/doc-collections/nureas/staff/sr1022/r3/) 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 2. Docket Number 3. Page VC SUMMER-UNIT 1 05000 395 1 OF 4

4. Title LOW REFRIGERANT RENDERS A-CHILLER NON-FUNCTIONAL AND A CHARGING PUMP INOPERABLE

5. Event Date 6. LER Number 7. Report Date 8. Other Facilities Involved Y Sequential Rev Facility Name Docket Number Month Day Year Month Day Year r Number No. 05000 Facility Name Docket Number 12 16 2015 2016 - 001 - 02 04 25 2018 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)

] 20.2201(d) i ] 20.2203(a)(3)(ii)

50.73(a)(2)(ii)(B)

50.73(a)(2)(viii)(B) 1

] 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)

50.73(a)(2)(iv)(A)

50.73(a)(2)(x)

10. Power Level )) 20.2203(a)(2)(ii)

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) i" ] 20.2203(a)(2)(iv)

50.46(a)(3)(H)

50.73(a)(2)(v)(C)

73.77(a)(1) 100 l 20.2203(a)(2)(v)

50.73(a)(2)(i)(A)

50.73(a)(2)(v)(C)

73.77(a)(2)(ii)

] 20.2203(a)(2)(vi) l7] 50.73(a)(2)(i)(B)

50.73(a)(2)(vii)

73.77(a)(2)(iii)

50.73(a)(2)(i)(C) ] Other (Specify in Abstract below or in NRC Form 366A

12. Licensee Contact for this LER Licensee Contact Telephone Number (Include Area Code)

Michael S. Moore (803) 345-4752

13. Complete One Line for each Component Failure Described in this Report Cause System Component Manufacturer Reportable to ICES Cause System Component Manufacturer Reportable to ICES X KM CHU N418 Y

14. Supplemental Report Expected Month Day Year

15. Expected Submission Date l Yes (If yes, complete 15. Expected Submission Date) [/] No Abstract (Limit to 1400 spaces, i.e., approximately 14 single-spaced typewritten lines)

A past operability review determined that HVAC System Mechanical Water Chiller A (XHX0001A-VU) had been non-functional from July 24, 2015, through September 17, 2015, due to a refrigerant leak in Circuit 2. XVM16506A-VU, Chilled Water Chiller "A" Liquid Injection Solenoid Inlet Valve Circuit 2, was replaced and post maintenance testing completed satisfactorily.

On February 24, 2016, Operations started Circuit 2 of XHX0001A-VU to support the interim action and discovered an additional leakage path that is the cause of the initial event described in LER-2016-001-00. An inter-circuit evaporator gasket leak was allowing refrigerant leakage from Circuit 2 to Circuit 1. The gaskets were replaced and post maintenance testing was completed satisfactorily.

This report is being submitted in accordance with 10 CFR 50.73(a)(2)(i)(B).

NRC FORM 366 (02-2018)

NRC FORM 366A (04-2017) Page 2 of 4 NRC FORM 366A (04-2017) Page 3 of 4 NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2017)

Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months . Reported lessons learned are incorporated into the licensing process and fed back to industry. Send

° " LICENSEE EVENT REPORT (LER) comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to CONTINUATION SHEET lnfocollects.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 (See NUREG-1022, R.3 for instruction and guidance for completing this form 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 http://www.nrc.aov/readina-rm/doc-collections/nureas/staff/sr1022/r3A collection.

NARRATIVE 3.0 SAFETY SIGNIFICANCE (continued)

The delta CDF for the 57 day period out of service is 4.61E-08/yr The delta LERF for the 57 day period out of service is 5.82E-10/yr 4.0 PREVIOUS OCCURRENCE On October 24, 2011, a refrigerant leak on Circuit 1 of XHX0001A-VU was observed. The leak was identified as conning from XVR16482A-VU, Chilled Water Chiller "A" Condenser Vessel Relief Valve Circuit 1A. XVR16482A-VU was reinstalled with new sealant and a follow up leak check was completed satisfactorily.

5.0 CORRECTIVE ACTIONS For the refrigerant leak around the threaded connection of XVM16506A-VU, Chilled Water Chiller "A" Liquid Injection Solenoid Inlet Valve Circuit 2, XVM16506-VU was replaced.

The gaskets were replaced on the north and south side of the evaporator per maintenance procedures. Post maintenance testing was conducted satisfactory to ensure the inter circuit leak was resolved.

NRC FORM 366A (04-2017) Page 4 of 4

Document Control Desk Attachment II CR-18-00799 RC-18-0056 Page 1 of 4 VIRGIL C. SUMMER NUCLEAR STATION (VCSNS)

DOCKET NO. 50-395 OPERATING LICENSE NO. NPF-12 ATTACHMENT II LER 2016-002-01

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (02-2018) Estimated burden per response to comply with this mandatory collection request 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months .

Reported lessons learned are incorporated into the licensing process and fed back to LICENSEE EVENT REPORT (LER) industry. Send comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail i ?? \ ^ee Pa9e 2 for required number of digits/characters for each block) to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget

/ (See NUREG-1022, R.3 for instruction and guidance for completing this form Washington, DC 20503. If a means used to impose an information collection does not

^ J1 http://www.nrc.aov/readina-rm/doc-collections/nureas/staff/sr1022/r3/) display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is notrequired to respond to, the information collection.

1. Facility Name 2. Docket Number 3. Page VC SUMMER-UNIT 1 05000 395 1 OF 3

4. Title PRESSURIZER HEATER INOPERABLE LONGER THAN TECHNICAL SPECIFICATION LIMITING CONDITION FOR OPERATION 3.4.3

5. Event Date 6. LER Number 7. Report Date 8. Other Facilities Involved Y Sequential Rev Facility Name Docket Number Month Day Year Month Day Year Number No. 05000 Facility Name Docket Number 07 22 2016 2016 - 002 - 01 04 25 2018 05000

9. Operating Mode 11. This Report is Submitted Pursuant to the Requirements of 10 CFR §: (Check all that apply) 20.2201 (b)

20.2203(a)(3)(i)

50.73(a)(2)(ii)(A)

50.73(a)(2)(viii)(A) 20.2201 (d) 20.2203(a)(3)(H)

50.73(a)(2)(ii)(B)

50.73(a)(2)(viii)(B) 1

] 20.2203(a)(1) l [ 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)

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)

J 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)(C)

73.77(a)(2)(H)

] 20.2203(a)(2)(vi) \7\ 50.73(a)(2)(i)(B)

50.73(a)(2)(vii)

73.77(a)(2)(iii)

50.73(a)(2)(i)(C) J Other (Specify in Abstract below or in NRC Form 366A

12. Licensee Contact for this LER Licensee Contact Telephone Number (Include Area Code)

Michael S. Moore (803) 345-4752

13. Complete One Line for each Component Failure Described in this Report Cause System Component Manufacturer Reportable to ICES Cause System Component Manufacturer Reportable to ICES E AB EHTR, 52 G080 Y

14. Supplemental Report Expected Month Day Year

15. Expected Submission Date l [ Yes (If yes, complete 15. Expected Submission Date) [/] No Abstract (Limit to 1400 spaces, i.e., approximately 14 single-spaced typewritten lines)

On July 22, 2016, a past operability review determined that the Pressurizer Backup Group 2 Heaters were inoperable for 94 hours0.00109 days 0.0261 hours 1.554233e-4 weeks 3.5767e-5 months , from 0600 on June 15, 2016, to 0400 on June 19, 2016. On June 18, 2016, the breaker (XSW1DB 05) that provides safety class 1E power to Pressurizer Backup Group 2 Heaters was found with its charging springs discharged. The closing coil plunger was found mechanically bound due to foreign material. The closing latch was unable to reset and the contacts did not allow the spring charging motor to energize and recharge the closing springs. The failed breaker XSW1DB 05 was swapped with a spare breaker and the Pressurizer Backup Group 2 Heaters were returned to service at 0400, June 19, 2016.

The time for which the Pressurizer Backup Group 2 Heaters were inoperable exceeds Technical Specification 3.4.3.a Limiting Condition for Operation of 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . Therefore, this report is being submitted in accordance with 10 CFR 50.73(a)(2)(i)(B).

NRC FORM 366 (02-2018)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2017)

Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months . Reported lessons learned are incorporated into the licensing process and fed back to industry. Send LICENSEE EVENT REPORT (LER) comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to CONTINUATION SHEET lnfocollects.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 (See NUREG-1022, R.3 for instruction and guidance for completing this form used to impose an information collection does not display a currently valid OMB control number, the http://www.nrc.gov/readina-rm/doc-collections/nureas/staff/sr1022/r3A NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

2. DOCKET NUMBER 3. LER NUMBER

1. FACILITY NAME YEAR SEQUENTIAL REV NUMBER NO.

VC SUMMER-UNIT 1 05000- 395 2016 - 002 - 01 NARRATIVE 1.0 EVENT DESCRIPTION On June 18, 2016, breaker XSW1DB 05 was found with charging springs discharged. The closing coil plunger was found mechanically bound in the up position. The closing latch was unable to reset and the contacts did not allow the spring charging motor to energize and recharge the closing springs.

A past operability evaluation, completed on July 22, 2016, determined that the breaker was not reliable for 94 hours0.00109 days 0.0261 hours 1.554233e-4 weeks 3.5767e-5 months from 0600 on June 15, 2016, to 0400, June 19, 2016. This event exceeded the Technical Specification (TS) 3.4.3.a Limiting Condition for Operation (LCO) of 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

2.0 EVENT ANALYSIS TS 3.4.3 requires a water volume less than or equal to 1288 cubic feet and at least two groups of pressurizer heaters, each having a capacity of at least 125 kW, to be operable during Modes 1, 2, and 3. The requirement that a minimum number of pressurizer heaters be operable enhances the capability of the plant to control Reactor Coolant System pressure and establish natural circulation. Pressurizer pressure is controlled by three components: electrical heaters, spray valves, and relief valves. The electrical heaters are energized when pressurizer pressure drops below a desired pressure. When the desired pressure is reached, the heaters are turned off.

The 78 pressurizer heaters have an installed capacity of 1420 kW which is divided between one control group and two backup groups. Proportional (Variable) Heaters are powered from bus 1C (XSW1C 02), Backup Group 1 is powered from XSW1DA (XSW1DA 12) and Backup Group 2 is powered from XSW1DB (XSW1DB 05). The two backup heater groups are on separate emergency generator supplied buses so that any single failure will not defeat operation or control of both groups. Additionally, the two backup heaters have automatic actions from the pressurizer level control. The Proportional (Variable) Heaters are supplied by non-safety power, thus the TS requirement refers only to the backup groups of pressurizer heaters. With one group of pressurizer heaters unavailable, two groups must be restored to operable status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , or be in at least hot standby within the next six hours and in hot shutdown within the following six hours.

On June 18, 2016 breaker XSW1 DB 05 was found with its charging springs discharged. The closing coil plunger was found mechanically bound in the up position. The closing latch was unable to reset and the contacts didn't allow the spring charging motor to energize and recharge the closing springs. The station replaced the breaker with a spare, completed the breaker retest, and cleared the R&R.

Station investigation of the failed breaker revealed foreign material was causing the plunger to stick. The foreign material was determined to be part of the cotter pin that was introduced during the refurbishment of the breaker conducted under a previous work order. The piece of cotter pin caused the plunger to fail after the coil was actuated.

NRC FORM 366A (04-2017) Page 2 of 3

NRC FORM 366A (04-2017) Page 3 of 3 Document Control Desk Attachment III CR-18-00799 RC-18-0056 Page 1of 5 VIRGIL C. SUMMER NUCLEAR STATION (VCSNS)

DOCKET NO. 50-395 OPERATING LICENSE NO. NPF-12 ATTACHMENT III LER 2016-003-02

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018) Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months .

Reported lessons learned are incorporated into the licensing process and fed back to LICENSEE EVENT REPORT (LER) industry. Send comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail

< S (fit' S ^ee Page 2 for required number of digits/characters for each block) to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget,

£ (See NUREG-1022, R.3 for instruction and guidance for completing this form Washington, DC 20503. If a means used to impose an information collection does not

\ ^ *<? http://www.nrc.aov/readina-rm/doc-collections/nureas/staff/sr1022/r3/) display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is notrequired to respond to, the information collection.

1. Facility Name 2. Docket Number 3. Page VC SUMMER-UNIT 1 05000 395 1 OF 4

4. Title STEAM PROPAGATION DOOR DISCOVERED PROPPED OPEN

5. Event Date 6. LER Number 7. Report Date 8. Other Facilities Involved Y Sequential Rev Facility Name Docket Number Month Day Year Month Day Year r Number No. 05000 Facility Name Docket Number 09 13 2016 2016 - 003 - 02 04 25 2018 05000

9. Operating Mode 11. This Report is Submitted Pursuant to the Requirements of 10 CFR §: (Check all that apply) 20.2201(b) 20.2203(a)(3)(i)

50.73(a)(2)(ii)(A)

50.73(a)(2)(viii)(A) 3 20.2201(d) 3 20.2203(a)(3)(ii)

50.73(a)(2)(ii)(B)

50.73(a)(2)(viii)(B) 1

] 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)

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)(ii)

50.73(a)(2)(v)(C)

73.77(a)(1) 100 ] 20.2203(a)(2)(v)

50.73(a)(2)(i)(A) \7\ 50.73(a)(2)(v)(D)

73.77(a)(2)©

] 20.2203(a)(2)(vi)

50.73(a)(2)(i)(B)

50.73(a)(2)(vii)

73.77(a)(2)(ii)

50.73(a)(2)(i)(C) \7\ Other (Specify in Abstract below or in NRC Form 366A)