ML25352A130
| ML25352A130 | |
| Person / Time | |
|---|---|
| Site: | Farley  (NPF-002, NPF-008) |
| Issue date: | 12/29/2025 |
| From: | Turner Z NRC/NRR/DORL/LPL2-1 |
| To: | Southern Nuclear Operating Co |
| Turner Z, NRR/DORL/LPL2-1 | |
| Shared Package | |
| ML25352A128 | List: |
| References | |
| EPID L-2025-LLR-0025 | |
| Download: ML25352A130 (0) | |
Text
December 29, 2025 LICENSEE:
Southern Nuclear Operating Company, Inc.
FACILITY:
Joseph M. Farley Nuclear Plant, Units 1 and 2
SUBJECT:
SUMMARY
OF DECEMBER 16, 2025, OBSERVATION MEETING HELD WITH SOUTHERN NUCLEAR OPERATING COMPANY, INC., REGARDING ALTERNATIVE REQUEST FNP-ISI-ALT-2025-10 FOR CONTAINMENT UNBONDED POST-TENSIONING SYSTEM INSERVICE INSPECTION REQUIREMENTS IN ACCORDANCE WITH 10 CFR 50.55(A)(Z)(1)
On December 16, 2025, an Observation meeting was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of Southern Nuclear Operating Company, Inc. (SNC, the licensee). The purpose of the meeting was for the NRC staff and SNC to discuss details related to the ongoing review of SNCs proposed alternative request FNP-ISI-ALT-2025-10 dated February 27, 2025 (Agencywide Documents and Access Management System (ADAMS) Accession No. ML25058A186), as supplemented by letter dated October 9, 2025 (ML25282A075).
A list of meeting attendees is provided in the Enclosure.
The meeting was noticed on the NRC public webpage on December 5, 2025 (ML25339A113).
The NRC staff opened the meeting with introductory remarks and a roll call of the attendees.
The SNC representative presented slides contained in ADAMS Accession No. ML25350A003.
SNC representatives discussed the following topics related to SNCs proposed alternative request:
(1) Hydrogen stress cracking (2) Anchor heads properties and locations (3) Water presence and locations (4) Augmented Examinations for 2012, 2017, and 2021 (5) ASME Code section IWL-2500 requirements; and (6) General Discussion Discussion The NRC staff asked these questions related to the following topics:
- 1. Hydrogen Stress Cracking Discuss what caused the hydrogen stress cracking during events in 1985, 2012, and 2017.
Discuss what actions the applicant has taken to detect potential widespread degradation beyond the sampled components. The NRC staff notes that the number of replaced or repaired anchor heads substantially exceeds the number of samples inspected.
- 2. Discuss and present the following with drawings or diagrams Sources of the material and material properties for the anchor heads, unreplaced anchor heads with potential high hardness and their locations.
Water presence and their locations, actions taken.
Factors contributing to low corrosion protection medium (CPM) base number and their locations, action taken.
- 3. The augmented examinations Discuss the tendon selection in 2012, 2017 and 2021 examinations.
Present the examination results and resolutions of non-conformances for the initial inspection and subsequent inservice inspections (ISIs) for the tendons requiring augmented examinations per the American Society of Mechanical Engineers (ASME Code), Subsection IWL, Table IWL-2521-2.
Present tendon force trends for the replaced or re-tensioned tendons during the events in 2012 and 2017.
Present the distribution of the replaced or re-tensioned hoop tendon locations using drawings or diagrams to demonstrate whether balanced effects of prestressing tendon system are maintained for the structural integrity of the containment structure.
During the discussion, SNC relayed additional information related to the containment tendon anchor heads to include previous inspection and surveillance data, anchor head replacement locations, root cause findings for previous inspection failures and corrective actions, in addition to quality assurance documentation.
SNC confirmed that no Rockwell hardness testing was performed for the anchor head failure in 1985. SNC stated that the anchor head failure in 2012 was initially attributed to a low corrosion protection medium (CPM) base number combined with high Rockwell hardness and moisture.
Following a similar failure in 2017, SNC concluded that both the 2012 and 2017 events were caused by hydrogen stress cracking associated with the high hardness of anchor head material from heat treatment Lot 10114, as both failed anchor heads originated from that same lot. It is SNCs opinion that a low CPM base number is not necessarily a cause of hydrogen stress cracking. Rather, SNC suggests that a combination of moisture and high hardness in the anchor head material increases the susceptibility of anchor heads to hydrogen cracking. Additionally, CPM base number measurements can be unreliable, as they are influenced by such factors as the sample location and the testing laboratory. Furthermore, SNC clarified samples of anchor heads from six of the ten total lots for Unit 1 were tested for Rockwell hardness; however, no samples from the seven lots (five original plus two additional lots) associated with Unit 2 were evaluated for Rockwell hardness. SNC stated that all of the installed anchor heads from Lot 10114 have since been replaced with no additional issues found in the 2021 inservice inspection (ISI).
SNC also stated that the group of tendons subject to augmented examinations will not be combined with the general tendon population, and augmented examinations were completed or will continue to be performed in accordance with the ASME Section XI Code.
Closing Remarks There was one member of the public in attendance, who did not have any comments.
The NRC staff did not make any regulatory decisions during the meeting. The NRC staff will continue to perform a thorough review of SNCs proposed alternative request. The NRC staff will make any regulatory decisions in writing in a timely manner. Public Meeting Feedback forms were available, but no comments were received.
The meeting adjourned at 11:55 am Eastern Time (ET).
Please direct any inquiries to Zachary.Turner@nrc.gov or 301-415-2258.
/RA/
Zachary M. Turner, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-348 and 50-364
Enclosure:
List of Attendees cc: Listserv
Enclosure LIST OF ATTENDEES DECEMBER 16, 2025, OBSERVATION MEETING WITH SOUTHERN NUCLEAR COMPANY REGARDING ALTERNATIVE REQUEST FNP-ISI-ALT-2025-10 FOR CONTAINMENT UNBONDED POST-TENSIONING SYSTEM INSERVICE INSPECTION REQUIREMENTS JOSEPH M. FARLEY NUCLEAR PLANT, UNITS 1 AND 2 ATTENDEE REPRESENTING Zach Turner U.S. Nuclear Regulatory Commission (NRC)
Mike Markley NRC Si Hwan Park NRC George Wang NRC Ian Tseng NRC John Lamb NRC Dawnmathews Kalathiveettil NRC Wes Sparkman Southern Nuclear Operating Company (SNC)
Ryan Joyce SNC Aaron Knighton SNC Scott Walden SNC Mark Doyle SNC Corey Thomas SNC James Annett Public
ML25352A128 (Package)
ML25339A113 (Meeting Notice)
ML25350A003 (SNC Slides)
ML25352A130 (Meeting Summary)
NRC-001 OFFICE NRR/DORL/LPL2-1/PM NRR/DORL/LPL2-1/LA NRR/DEX/ESEB/BC NAME ZTurner KZeleznock ITseng DATE 12/18/2025 12/23/2025 12/22/2025 OFFICE NRR/DORL/LPL2-1/BC NRR/DORL/LPL2-1/PM NAME MMarkley (SWilliams for)
ZTurner DATE 12/29/2025 12/29/2025