ML20069F270

Voluntary Supplement to Special Report 2019-003 RCS Subcooling Margin Monitor Inoperable

ML20069F270
Person / Time
Site:	Summer
Issue date:	03/09/2020
From:	Lippard G Dominion Energy South Carolina
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
19-388A
Download: ML20069F270 (3)

Text

V. C. Summer Nuclear Station Bradham Blvd & Hwy 215, Jenkinsville, SC 29065

~ Dominion Mailing Address: ~ Energy P.O. Box 88, Jenkinsville, SC 29065 Dominion Energy.co m March 9, 2020 Attn : Document Control Desk Serial No.19-388A U. S. Nuclear Regulatory Commission VCS-LIC/JRB RO Washington , DC 20555-0001 Docket No. 50-395 License No. NPF-12 DOMINION ENERGY SOUTH CAROLINA, INC.

VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) UNIT 1 VOLUNTARY SUPPLEMENT TO SPECIAL REPORT 2019-003 RCS SUBCOOLING MARGIN MONITOR INOPERABLE Dominion Energy South Carolina, Inc. (DESC) is subm itting this voluntary supplement to Special Report 2019-003 (NRC Adams Accession Number ML192800380), previously submitted pursuant to the requirements of Technical Specifications (TS) 3.3.3.6 and 6.9.2. This update addresses one of the required Reactor Coolant System (RCS) Subcooling Margin Instrument Loop/Indicator monitoring channels being inoperable for more than thirty (30) days.

During calibration of RCS Subcooling Margin Monitor 'B', in accordance with Surveillance Requirement 4.3.3.6 (Table 3.3-1O; 10, 12), it was identified that the monitor was inoperable for certain analog inputs. The monitor was declared inoperable on August 26, 2019.

The failure of RCS Subcooling Margin Monitor 'B' (ITM004998) was captured in the station's corrective action program (CR-19-03018) . The monitor's power supply and computer board assembly (A5 card) were shipped to an offsite vendor for troubleshooting and repair. While RCS Subcooling Margin Monitor 'B' is inoperable, RCS Subcooling Margin Monitor 'A' remains operable and is available to monitor RCS subcooling . Additionally , an alternate method of monitoring is available via the plant process computer subcooling calculation .

The initial attempts to fully repair RCS Subcooling Margin Monitor 'B' were unsuccessful. VCSNS is continuing to troubleshoot the monitor in an attempt to repair it. Concurrently, VCSNS is developing an Engineering Change Request to replace the monitor during its upcoming Refueling Outage RF-25 (May 2020), if repair attempts are unable to restore operability.

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

Sincerely,

~ ippa~d Site Vice President V.C . Summer Nuclear Station

Serial No. 19-388A Docket No. 50-395 Page 2 of 2 Commitments contained in this letter: None cc: G. J. Lindamood - Santee Cooper L. Dudes - NRC Region II S. A Williams - NRC Project Manager NRC Resident Inspector

Serial No. 19-388A Voluntary Supplement to Special Report 2019-003: RCS Subcooling Margin Monitor Inoperable be: page 1 of 1 be: R. R. Haselden - VCS J. H. Hamilton - VCS C. D. Sly - IN2SE M. S. Moore - VCS J. A. Langan - MPS N. Turner- NAPS R. Philpot - SPS James Roth - IN2SE Stacey Nelson - IN2SE W. S. Blair - RS RTS (CR-19-03018)

File (818.08)

PRSF-VCS Concurrences See Correspondence Routing and Approval CHOP Sheet Verification of Accuracy None Action Plan None Changes to the UFSAR, USAR, QA Topical Report. ISFSI FSAR, DSAR or PSDAR None