ML22066A484

Review of the Spring 2021 Steam Generator Tube Inspection Report

ML22066A484
Person / Time
Site:	Surry
Issue date:	03/09/2022
From:	John Klos Plant Licensing Branch II
To:	Stoddard D Virginia Electric & Power Co (VEPCO)
John Klos (301) 415-5136
References
EPID L-2021-LRO-0046
Download: ML22066A484 (4)

Text

March 9, 2022

Mr. Daniel G. Stoddard Senior Vice President and Chief Nuclear Officer Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711

SUBJECT:

SURRY POWER STATION, UNIT 1 - REVIEW OF THE SPRING 2021 STEAM GENERATOR TUBE INSPECTION REPORT (EPID L-2021-LRO-0046)

Dear Mr. Stoddard:

By letter dated August 27, 2021, Agencywide Documents Access and Management System (ADAMS) Accession No. ML21243A313, as supplemented by letter dated February 9, 2022 (ADAMS Accession No. ML22040A101), Virginia Electric and Power Company (the licensee) submitted information summarizing the results of the spring 2021 steam generator tube inspections performed at Surry Power Station, Unit 1, during the end-of-cycle 30 refueling outage.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the documents referenced above and concludes that the licensee provided the information required by their technical specifications and that no additional follow-up is required at this time. The enclosure documents the NRC staffs review of the submittals.

If you have any questions, please contact me at (301) 415-5136, or via email at John.Klos@nrc.gov.

Sincerely,

/RA/

John Klos, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Docket Nos. 50-280 and 50-281

Enclosure:

Review of Steam Generator Tube Inspection Report

cc: Listserv REVIEW OF THE SPRING 2021 STEAM GENERATOR

TUBE INSPECTION REPORT

VIRGINIA ELECTRIC AND POWER COMPANY

SURRY POWER STATION UNIT 1

DOCKET NO. 50-280

By letter dated August 27, 2021, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML21243A313), as supplemented by letter dated February 9, 2022, (ADAMS Accession No. ML22040A101), Virginia Electric and Power Company (the licensee) submitted information summarizing the results of the spring 2021 steam generator tube inspections performed at Surry Power Station, Unit 1 (Surry, Unit 1) during the end-of-cycle (EOC) 30 refueling outage (RFO).

The three replacement steam generators (SGs) at Surry Unit 1 were installed in 1981.

Westinghouse fabricated the replacement SGs, and each SG contains 3,342 thermally treated Alloy 600 tubes that have a nominal outside diameter of 0.875 inches and a nominal wall thickness of 0.050 inches. The tubes were hydraulically expanded at both ends for the full length of the tubesheet and are supported by stainless steel tube support plates. The U-bends of the tubes installed in rows 1 through 8 were thermally stress relieved after bending.

The licensee provided the scope, extent, methods, and results of their 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 NRC staff has the following observations:

The licensee reported one indication, in SG C, of a circumferential primary water stress corrosion cracking approximately 0.34 inches below the top of the tubesheet (TTS) on the hot leg (HL), at a historical eddy current indication identified as a single circumferential anomaly. The location of the tube is Row 11 Column 42. The crack was detected by the

+Point' rotating probe and sized with the +Point' probe at 41 percent through-wall and 28 degrees in circumferential extent. The 100 percent HL TTS array probe examination did not detect the crack; however, the licensees review of the array probe data revealed a small and non-reportable signal at that location. The licensees review of historical +Point' results concluded that a discontinuity signal was discerned initially during the fall 2010 inspection (RFO 23) and that the depth m easurement has not changed significantly since the spring 2015 (RFO 26), nor the spring 2018 (RFO 28) inspections.

The licensees February 9, 2022, letter provides a summary of the foreign objects removed from the SGs during RFO 30 and the disposition of foreign objects identified but not removed.

The licensee performed repairs on the primary moisture separator riser barrels due to localized erosion on the outside surface, apparently due to impingement of feedwater discharge through a feedwater ring J-nozzle. The licensee repaired the barrels by installing Alloy 600 impingement plates over the degraded areas. Similar erosion of riser barrels had been detected and repaired previously in Surry Units 1 and 2.

Enclosure

Based on the review of the information provi ded, the NRC staff concludes that the licensee provided the information required by their techni cal specifications. In addition, the NRC staff concludes that there are no technical issues that warrant additional follow-up action at this time since 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: G. Makar

ML22066A484 OFFICE DORL/LPL2-1/PM DORL/LPL2-1/LA NRR/DNRL/NCSG/BC NAME JKlos KGoldstein SBloom DATE 03/04/2022 03/07/2022 02/23/2022 OFFICE DORL/LPL2-1/BC DORL/LPL2-1/PM NAME MMarkley JKlos DATE 03/08/2022 03/09/2022