ML26020A161
| ML26020A161 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 01/15/2026 |
| From: | Sierra T NRC/NRR/DORL/LPL2-2 |
| To: | Southern Nuclear Operating Co |
| References | |
| EPID L-2025-LRO-0056 | |
| Download: ML26020A161 (0) | |
Text
From:
Tony Sierra To:
"btrothsc@southernco.com" Cc:
"rmjoyce@southernco.com"; Tony Sierra
Subject:
For Your Review - DRAFT RAI Questions - Vogtle, Unit 2, SG Inspection Report Date:
Thursday, January 15, 2026 9:09:00 AM
- Ben,
By letter dated September 26, 2025 (Agencywide Documents Access System (ADAMS)
Accession No. ML25269A150), Southern Nuclear Operating Company (SNC, the licensee),
submitted information summarizing the results of the spring 2025 steam generator (SG) tube inspections performed at Vogtle Electric Generating Plant (Vogtle), Unit 2, during refueling outage (RFO) 24 (U2R24).
The U.S. Nuclear Regulatory Commission (NRC) staff has determined that additional information is required for the staff to complete its review. The NRC staffs draft requestion for additional information (RAI) is included.If SNC requires clarification on this draft RAI, SNC should provide me multiple days and times for availability by noon on January 20, 2026. If no clarification is required, this draft RAI will be considered a formal RAI, and a response will be expected within 30 days.
If you have any questions, please contact me.
Thank you
Tony Sierra, Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
DRAFT REQUEST FOR ADDITIONAL INFORMATION (RAI)
By letter dated September 26, 2025 (Agencywide Documents Access System (ADAMS)
Accession No. ML25269A150), Southern Nuclear Operating Company (SNC, the licensee),
submitted information summarizing the results of the spring 2025 steam generator (SG) tube inspections performed at Vogtle Electric Generating Plant (Vogtle), Unit 2, during refueling outage (RFO) 24 (U2R24).
Regulatory Basis Technical Specification (TS) 5.6.10 for Vogtle, Unit 2, requires that a report be submitted within 180 days after the initial entry into hot shutdown (MODE 4) following completion of an inspection of the SGs performed in accordance with TS 5.5.9, which requires that a SG Program be established and implemented to ensure SG tube integrity is maintained.
DRAFT RAI Question 1 Table 1 of the report lists the X-probe (detection) and the +Point probe (detection and sizing) as techniques used for detection and sizing of outside diameter stress corrosion cracking (ODSCC) at dents and dings. At the bottom of page E-7, the description of
ODSCC indications at dents and dings states there were two axial ODSCC indications that measured less than 40 percent through-wall (TW) detected at a dent by the +Point probe.
- 1. Please clarify whether theseaxial ODSCC indications were detected by the X-probe.
DRAFT RAI Question 2 Section 9.0 of the report, beginning at the bottom of page E-9, discusses a tube with a possible loose part (PLP) indication and an adjacent tube with an indication of 37 percent TW tube wear from a foreign object not associated with a legacy foreign object. The indications are at the top surface of the baffle plate on the hot leg (BPH). The report states that the tubes with the wear and PLP indications, along with four adjacent tubes, were preventively plugged and stabilized to form a protective box. Therefore, according to the report, no in-service tubes are expected to wear as a result of the PLP at this location.
The report does not discuss any attempts to characterize or retrieve the object, or the basis for concluding that the object will not move to another location.
Please address the following:
- 1.
- a. Discuss any attempts to visually characterize or retrieve an object that produced the PLP signal on the tube at Row 58, Column 50 (R58C50) and apparently caused wear on the adjacent tube (R58C51). Provide any information gained from the characterization and retrieval attempts.
- b. Describe any additional evaluation supporting the conclusion that the object will not affect other inservice tubes. The NRC staff notes that tubes R58C50 and R58C51 appear to be at the periphery of the BPH, and, therefore, the object may also be at the periphery of the BPH and able to migrate to another location.