ML23115A212
| ML23115A212 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 05/01/2023 |
| From: | Klos L Plant Licensing Branch II |
| To: | Pigott E Duke Energy Carolinas |
| Klos L | |
| References | |
| EPID L-2022-LRO-0141 | |
| Download: ML23115A212 (1) | |
Text
May 1, 2023 Mr. Edward Pigott Site Vice President Duke Energy Carolinas, LLC McGuire Nuclear Station 12700 Hagers Ferry Road Huntersville, NC 28078-8985
SUBJECT:
MCGUIRE NUCLEAR STATION, UNIT 1 - REVIEW OF THE SPRING 2022 STEAM GENERATOR TUBE INSPECTION REPORT (EPID: L-2022-LRO-0141)
Dear Mr. Pigott:
By letter dated October 25, 2022, Duke Energy Carolinas, LLC (the licensee), submitted information summarizing the results of the spring 2022 steam generator inspections performed at McGuire Nuclear Station, Unit 1, during refueling outage 28 (M1R28).
The U.S. Nuclear Regulatory Commission (NRC) staff has completed its review of the report 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 submittal.
If you have any questions, please contact me at 301-415-5136 or via e-mail at John.Klos@nrc.gov.
Sincerely,
/RA/
L. John Klos, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-369
Enclosure:
Review of Steam Generator Tube Inspection Report cc: Listserv
MCGUIRE NUCLEAR STATION, UNIT 1 REVIEW OF THE SPRING 2022 STEAM GENERATOR TUBE INSPECTION REPORT DOCKET NO. 50-369 By letter dated October 25, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22298A071), Duke Energy Carolinas, LLC (the licensee), submitted information summarizing the results of the spring 2022 steam generator (SG) tube inspections performed at McGuire Nuclear Station, Unit 1 (McGuire, Unit 1), during refueling outage 28 (M1R28). The licensee provided additional information concerning the inspections in a letter dated March 16, 2023 (ML23075A206), which supersedes the letter dated February 15, 2023 (ML23046A217).
McGuire, Unit 1, has four model CFR80 SGs manufactured by Babcock and Wilcox Canada that were installed in 1997. Each SG has 6,633 thermally treated Alloy 690 tubes, which have a nominal outside diameter of 0.688 inches and a nominal wall thickness of 0.040 inches. The tubes have a triangular pitch of 0.930 inches and were hydraulically expanded at each end for the full depth of the 26.63-inch thick (without cladding) tubesheet. The tubes are supported by nine stainless steel lattice grid support plates and eight fan bars. A feedwater equalization header also functions as a foreign object trapping device.
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, such as 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 has the following observations:
Two tubes were preventatively plugged in SG 1B due to possible loose parts.
The licensee clarified in its letter dated March 16, 2023, that there are 23 foreign object wear indications in the McGuire, Unit 1, SGs and that an indication characterized as lattice grid wear during M1R25 (fall 2017, ML18023A160) in SG 1C (Tube Row 22 Column 104) was re-characterized as a foreign object wear indication during M1R28 (spring 2022).
During M1R28, the licensee performed visual examinations in the SG 1A steam drum.
The licensee compared 14 separators inspected during M1R25 and M1R28 and stated that there was no visible change in the erosion patterns. The letter dated March 16, 2023, clarified that only the SG 1A steam drum was visually inspected during M1R25.
The licensee further clarified that the SG 1A steam drum was chosen as the lead for consistent monitoring and trending. During M1R22, the SG 1D steam drum was inspected, and the rates of degradation were comparable with those of the SG 1A steam drum. The licensee also stated in its letter dated March 16, 2023, that current inspection findings in the SG 1A steam drum do not indicate a need to inspect the other SG steam drums for McGuire, Unit 1.
Based on the review of the information provided, the staff concludes that the licensee provided the information required by their technical specifications. In addition, the 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.
- by email OFFICE NRR/DORL/LPL2-1/PM NRR/DORL/LPL2-1/PM NRR/DORL/LPL2-1/LA NAME ZTurner JKlos KGoldstein DATE 4/26/2023 04/26/2023 04/26/2023 OFFICE NRR/DNRL/NCSG/BC*
NRR/DORL/LPL2-1/BC*
NRR/DORL/LPL2-1/PM NAME SBloom MMarkley JKlos DATE 04/20/2023 04/28/2023 05/01/2023