ML21022A411
| ML21022A411 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 01/27/2021 |
| From: | Vaughn Thomas NRC/NRR/DORL/LPL4 |
| To: | Lippard G South Carolina Electric & Gas Co |
| Thomas Vaughn-NRR/DORL 301-415-5897 | |
| References | |
| EPID L-2019-LRO-0105 | |
| Download: ML21022A411 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 January 27, 2021 Mr. George A. Lippard Site Vice President V.C. Summer Nuclear Station Dominion Energy South Carolina P.O. Box 88 Jenkinsville, SC 29065
SUBJECT:
VIRGIL C. SUMMER NUCLEAR STATION, UNIT 1REVIEW OF STEAM GENERATOR INSERVICE INSPECTION REPORT FOR UNIT 1 END-OF-CYCLE-24 REFUELING OUTAGE (EPID L-2019-LRO-0105)
Dear Mr. Lippard:
By letter dated May 14, 2019 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19134A372), as supplemented by letter dated December 14, 2020 (ADAMS Accession No. ML20349A326), Dominion Energy South Carolina, Inc. (the licensee),
submitted information summarizing the results of inspections at Virgil C. Summer Nuclear Station, Unit 1 (Summer Unit 1), in accordance with Technical Specification (TS) 6.9.1.12, Steam Generator Tube Inspection Report. The report summarizes the steam generator tube inspections that the licensee performed in fall 2018 during the Summer Unit 1 cycle 24 refueling outage. The U.S. Nuclear Regulatory Commission (NRC) staff reviewed the submittal and concludes that the licensee provided the information required by TS 6.9.1.12. The enclosure documents the NRC staffs review of the submittal and completes the NRC staffs efforts for Enterprise Project Identifier (EPID) L-2019-LRO-0105.
Any inquiries can be directed to me at 301-415-5897 or by e-mail to Vaughn.Thomas@nrc.gov.
Sincerely,
/RA/
Vaughn V. Thomas, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-395
Enclosure:
As stated cc w/encl: Listserv
Enclosure REVIEW BY THE OFFICE OF NUCLEAR REACTOR REGULATION FALL 2018 STEAM GENERATOR TUBE INSERVICE INSPECTION REPORT DOMINION ENERGY SOUTH CAROLINA VIRGIL C. SUMMER NUCLEAR STATION, UNIT 1 DOCKET NO. 50-395 By letter dated May 14, 2019 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19134A372), as supplemented by letter dated December 14, 2020 (ADAMS Accession No. ML20349A326), Dominion Energy South Carolina, Inc. (the licensee),
submitted information summarizing the results of the fall 2018 steam generator (SG) inspections performed at Virgil C. Summer Nuclear Station, Unit 1 (Summer Unit 1), during the end-of-cycle-24 refueling outage (RFO 24).
The three replacement SGs at Summer, Unit 1, were fabricated by Westinghouse and installed in 1994. Each SG contains 6,307 thermally treated Alloy 690 tubes, with a nominal outside diameter of 0.6875 inches and a nominal wall thickness of 0.040 inches. The tubes are supported by nine 1.125-inch-thick Type 405 stainless steel tube support plates (TSPs) with trefoil, broached holes. Four sets of Type 405 stainless steel antivibration bars support the U-bend sections. The first 17 rows of tubing were stress relieved during fabrication. A flow distribution baffle plate is present between the tubesheet and the lowest support plate, and a sludge collector is placed above each primary separator.
The licensee provided the scope, extent, methods, and results of the SG tube inspections in the documents referenced above. In addition, the licensee described corrective actions (e.g., tube plugging) taken in response to the inspection findings. Based on the review of the information provided, the U.S. Nuclear Regulatory Commission (NRC) staff makes the following observations:
Ten tubes were plugged during RFO 24; three tubes (two in SG A and one in SG B) due to foreign object (FO) wear and seven tubes (five in SG A and two in SG C) due to indications of possible loose parts (PLPs). The licensee clarified that no FOs were present at the three FO wear locations, five of the seven tubes with PLPs were not accessible for secondary-side inspection and FO search and retrieval, and two of the seven tubes with PLPs were associated with confirmed FOs that could not be removed.
The licensees RFO 24 condition monitoring and final operational assessment concluded that FOs returned to service during RFO 24 would not experience FO wear that would violate SG tube structural or leakage integrity.
Heavy deposit formations were identified during the visual inspection of the top (ninth)
TSP in each SG. The licensee reported tube denting at the 09H TSP in SG C and stated that it could be related to the heavy deposit formation. The licensee also noted (in the December 14, 2020, letter) that SG chemical cleaning was performed during RFO 25.
Based on its review of the information provided, the NRC staff concludes that the licensee provided the information required by Technical Specification 6.9.1.12, Steam Generator Tube
Inspection Report. In addition, the NRC staff concludes that there are no technical issues that warrant additional followup action because the inspections appear to be consistent with the objective of detecting potential tube degradation and the inspection results appear to be consistent with industry operating experience at similarly designed and operated units.
Principal Contributor: Leslie S. Terry Date: January 27, 2021
ML21022A411 OFFICE NRR/DORL/LPL4/PM NRR/DORL/LPL2-1/LA NRR/DNLR/NCSG/BC NAME VThomas KGoldstein SBloom DATE 01/14/2021 01/27/2021 01/13/2021 OFFICE NRR/DORL/LPL2-1/BC NRR/DORL/LPL2-1/PM NAME MMarkley (SWilliams for)
VThomas DATE 01/27/2021 01/27/2021