ML25219A764
| ML25219A764 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 08/07/2025 |
| From: | John Lamb Plant Licensing Branch II |
| To: | Wilson C Southern Nuclear Operating Co |
| References | |
| Download: ML25219A764 (4) | |
Text
From:
John Lamb Sent:
Thursday, August 7, 2025 3:59 PM To:
CWILSON@southernco.com Cc:
Joyce, Ryan M.; Lowery, Ken G.; Steven Bloom; Greg Makar; Paul Klein; Andy Johnson; Leslie Terry; Michael Markley; Zach Turner; Alan Blamey; Alejandro Alen Arias; Christian Scott; Nicole Coovert; Theo Fanelli; JP Parent
Subject:
FYI: Request for Steam Generator Inspection Call with Vogtle Unit 4
- Cotasha, The NRC staff would like to thank SNC for agreeing to have a conference call regarding the steam generator (SG) tube inspections during the first refueling outage (RFO), scheduled for fall 2025 for Vogtle Electric Generating Plant (Vogtle), Unit 4.
STEAM GENERATOR TUBE INSPECTION DISCUSSION POINTS The following discussion points have been prepared to facilitate the conference call that will be arranged with SNC to discuss the results of the SG tube inspections to be conducted during the upcoming fall 2025, Vogtle, Unit 4, RFO. This conference call will be scheduled to occur towards the end of the planned SG tube inspections, but before Vogtle, Unit 4, completes the inspections and repairs.
The NRC staff plans to document a publicly available summary of the conference call, as well as any material that is provided in support of the call.
- 1. Discuss any trends in the amount of primary-to-secondary leakage observed during the recently completed cycle.
- 2. Discuss whether any secondary side pressure tests were performed during the outage and the associated results.
- 3. Discuss any exceptions taken to the industry guidelines.
- 4. For each steam generator, provide a description of the inspections performed including the areas examined and the probes used (e.g., dents/dings, sleeves, expansion-transition, U-bends with a rotating probe), the scope of the inspection (e.g., 100% of dents/dings greater than 5 volts and a 20% sample between 2 and 5 volts), and the expansion criteria.
- 5. For each area examined (e.g., tube supports, dent/dings, sleeves, etc), provide the following:
- a. A summary of the number of indications identified to date for each degradation mode (e.g., number of circumferential primary water stress corrosion cracking indications at the expansion transition).
- b. For the most significant indications in each area, provide an estimate of the severity of the indication (e.g., voltage, depth, and length of the indication), including whether tube integrity (structural and accident induced leakage integrity) was maintained during the previous operating cycle. In addition, discuss any analyses performed specifically for the most significant indications to demonstrate tube integrity.
- c. Recent operating experience in both the U.S. and internationally has indicated that very large steam generators have increased susceptibility to aggressive wear from tube supports on tubes in the low rows. Describe the examinations and results of inspections
performed in the low row tubes and how the results will be considered in the operational assessment.
- 6. Describe repair/plugging plans.
- 7. Describe in-situ pressure test and tube pull plans and results (as applicable and if available).
- 8. Discuss the following regarding loose parts:
- a. The inspections performed to detect loose parts.
- b. A description of any loose parts detected and their location within the SG (including the source or nature of the loose part, if known).
- c. If the loose parts were removed from the SG.
- d. Indications of tube damage associated with the loose parts.
- 9. Discuss the scope and results of any secondary side inspection and maintenance activities (e.g., in-bundle visual inspections, feedring inspections, sludge lancing, assessing deposit loading, etc).
- 10. Discuss any unexpected or unusual results.
- 11. Provide the schedule for SG-related activities during the remainder of the current outage.
Hearing Identifier:
NRR_DRMA Email Number:
2789 Mail Envelope Properties (MN2PR09MB5084466E162D4F1ABF6B283FFA2CA)
Subject:
FYI Request for Steam Generator Inspection Call with Vogtle Unit 4 Sent Date:
8/7/2025 3:58:34 PM Received Date:
8/7/2025 3:58:00 PM From:
John Lamb Created By:
John.Lamb@nrc.gov Recipients:
"Joyce, Ryan M." <rmjoyce@southernco.com>
Tracking Status: None "Lowery, Ken G." <kglowery@southernco.com>
Tracking Status: None "Steven Bloom" <Steven.Bloom@nrc.gov>
Tracking Status: None "Greg Makar" <Gregory.Makar@nrc.gov>
Tracking Status: None "Paul Klein" <Paul.Klein@nrc.gov>
Tracking Status: None "Andy Johnson" <Andrew.Johnson@nrc.gov>
Tracking Status: None "Leslie Terry" <Leslie.Terry@nrc.gov>
Tracking Status: None "Michael Markley" <Michael.Markley@nrc.gov>
Tracking Status: None "Zach Turner" <Zachary.Turner@nrc.gov>
Tracking Status: None "Alan Blamey" <Alan.Blamey@nrc.gov>
Tracking Status: None "Alejandro Alen Arias" <alejandro.alenarias@nrc.gov>
Tracking Status: None "Christian Scott" <Christian.Scott@nrc.gov>
Tracking Status: None "Nicole Coovert" <Nicole.Coovert@nrc.gov>
Tracking Status: None "Theo Fanelli" <Theodore.Fanelli@nrc.gov>
Tracking Status: None "JP Parent" <Jason.Parent@nrc.gov>
Tracking Status: None "CWILSON@southernco.com" <CWILSON@southernco.com>
Tracking Status: None Post Office:
MN2PR09MB5084.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 3488 8/7/2025 3:58:00 PM Options Priority:
Normal Return Notification:
No
Reply Requested:
No Sensitivity:
Normal Expiration Date: