IR 05000483/2025011
| ML25339A000 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 12/08/2025 |
| From: | Greg Warnick NRC/RGN-IV/DORS/EB2 |
| To: | Karenina Scott Ameren Missouri |
| References | |
| IR 2025011 | |
| Download: ML25339A000 (0) | |
Text
December 08, 2025
SUBJECT:
CALLAWAY PLANT - LICENSEE RENEWAL REPORT 05000483/2025011
Dear Kent Scott:
On December 3, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an in-office inspection at Callaway Plant and discussed the results of this inspection with Todd Witt, Director, Nuclear Engineering Design and Regulatory Affairs and other members of your staff.
The results of this inspection are documented in the enclosed report.
No findings or violations of more than minor significance were identified during this inspection.
This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely, Gregory G. Warnick, Chief Engineering Branch 2 Division of Operating Reactor Safety Docket No. 05000483 License No. NPF-30
Enclosure:
As stated
Inspection Report
Docket Number:
05000483
License Number:
Report Number:
Enterprise Identifier:
I-2025-011-0037
Licensee:
Union Electric Company Ameren Missouri
Facility:
Callaway Plant
Location:
Steedman, MO
Inspection Dates:
December 1, 2025 - December 3, 2025
Inspectors:
G. Pick, Senior Reactor Inspector
Approved By:
Gregory G. Warnick, Chief
Engineering Branch 2
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting a licensee renewal inspection at Callaway Plant, in accordance with the Reactor Oversight Process. The Reactor Oversight Process is the NRCs program for overseeing the safe operation of commercial nuclear power reactors. Refer to https://www.nrc.gov/reactors/operating/oversight.html for more information.
List of Findings and Violations
No findings or violations of more than minor significance were identified.
Additional Tracking Items
None.
INSPECTION SCOPES
This inspection was conducted using the appropriate portions of the inspection procedures in effect at the beginning of the inspection unless otherwise noted. Currently approved inspection procedures with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html.
Samples were declared complete when the inspection program requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspector reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.
OTHER ACTIVITIES
- TEMPORARY INSTRUCTIONS, INFREQUENT AND ABNORMAL
===71003 - Post-Approval Site Inspection for License Renewal Phase 3 Inspection activities are performed after the licensee enters the period of extended operation. The period of extended operation is an additional 20 years beyond the original 40-year licensed term. Callaway Plant began the period of extended operation on October 18, 2024.
The inspector performed this in-office inspection to evaluate whether the licensee completed outstanding actions required to comply with the license renewal license condition and commitments and effectively implemented outstanding actions related to aging management programs.
During this in-office inspection, the inspector evaluated the licensee actions related to commitments not closed during the Phase 2 license renewal inspection (Inspection Report 05000483/2024011 (ML24117A310)).
The inspector reviewed program documents, inspection results, licensing correspondence, engineering reports, and corrective action documents. The inspector interviewed the program owners to discuss the technical resolution related to the commitments.
The inspector closed Commitments 32 and 45 and their associated aging management programs during this inspection.
Post-Approval Site Inspection for License Renewal===
(1)19.1.31 Structures Monitoring (XI.S6) and Commitment 45 This existing inspection and monitoring program manages the effects of aging for concrete elements, structural steel, roof systems, masonry walls and metal siding, non ASME mechanical supports, and electrical supports. The licensee included the required inspections of their masonry walls and water control structures aging management programs as part of this program. The program manages the following aging effects for in-scope structures and structural elements: concrete cracking and spalling, cracking and distortion, cracking with loss of material, cracking with loss of bond or loss of material, increase in porosity and permeability, loss of strength, loss of material, loss of mechanical function, loss of sealing, and reduction in concrete anchor capacity.
Commitment 45 specified:
- Enhance the regulatory guide 1.127, Inspection of Water-Control Structures Associated with Nuclear Power Plants, program and procedures to include the concrete structures in the turbine building that provide a flow path for the circulating water system in the scope of the program.
During the last inspection, the inspector identified that the licensee had not monitored the concrete tunnels (also known as vaults) below the turbine building that provided a return path for circulating water because they considered them inaccessible. The inspector determined that the licensee could access the vault during outages when operations secure circulating water flow to clean the cooling tower basin.
During this inspection, the inspector determined that the licensee had inspected the vaults. The inspector reviewed the vault inspection report including photographs of the concrete condition. After 40 years the inspection identified that the concrete remained in good condition with surface level cracking, flaking/spalling, minor aggregate popouts, and joint overpour. The licensee planned to implement future inspections at the same frequency of other structural inspections.
Based on the review of the procedures, work orders, the inspection report, and discussions with licensee personnel, the inspector did not identify any findings or violations associated with this aging management program.
(2)19.2.3 Concrete Containment Tendon Prestress Program (X.S1)and Commitment 32 This existing program, which is part of the ASME section XI, subsection IWL inservice inspection program, manages loss of tendon prestress consistent with the requirements of 10 CFR 50.55a(b)(2)(viii)(B).
Commitment 32 specified:
Enhance the program to:
- Include random samples for the 40-, 45-, 50-, and 55-year surveillances.
- Extend the predicted lower limit lines for the vertical and hoop tendon groups to 60 years.
- Require the final report for each surveillance interval to plot the measured results against time and to include the predicted lower limit, minimum required value, and trend lines.
- Require a regression analysis consistent with the requirements of Information Notice 99-10, Degradation of Prestressing Tendon Systems in Prestressed Concrete Containments, revision 1, attachment 3, Comparison and Trending of Prestressing Forces.
During a previous inspection, the inspector did not close the commitment nor the aging management program because the licensee had not yet received a decision from NRC related to an associated relief request, which would delay the required 5-year testing for the 40-year inspection by another 5 years.
During this inspection, the inspector reviewed correspondence between the NRC and the licensee. The inspector verified that the NRC had approved relief request C3R-01, Request for Relief from Requirements of ASME BPV Code,Section XI, Subsection IWL Regarding Examination and Testing of the Unbonded Post-Tensioning System. The NRC had granted this relief request as an one-time extension of the 40th year in the third interval to the 45th year. The licensee indicated that they planned to perform the examination in the summer of 2030.
Based on the review of the procedures, work orders and correspondence, and discussions with licensee personnel, the inspector did not identify any findings or violations associated with this aging management program.
INSPECTION RESULTS
No findings were identified.
EXIT MEETINGS AND DEBRIEFS
The inspector verified no proprietary information was retained or documented in this report.
- On December 3, 2025, the inspector presented the license renewal inspection results to Todd Witt, Director, Nuclear Engineering Design and Regulatory Affairs and other members of the licensee staff.
NRC closed commitments: 3, 9, 20, 41, and 42 in Inspection Report 05000483/2023010.
NRC closed commitments: 1, 2, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 33, 34, 35, 36, 37, 38, 39, 40, 43, 44, and 46 in Inspection Report 05000483/2024011 During this inspection, the inspectors closed commitments 32 and 45.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Corrective Action
Documents
CR-
2401621, 202401988, 202401998, 202402035, 202402038,
2402039, 202402053, 202502696
Callaway Plant, Unit No. 1 - Supplemental Information Needed
for Acceptance of Requested Licensing Action Re: Request for
Relief from Requirements of ASME Code,Section XI,
Subsection IWL Examination And Testing of the Unbonded
Post-Tensioning System (EPID L-2023-LLR-0061)
2/14/2023
Reinforced Concrete Structures under the Turbine Building and
in Yard Area
8/7/2025
Callaway Plant, Unit No. 1 - Regulatory Audit Summary
Concerning Review of Request No. C3R-01 for Proposed
Alternative to ASME Code, Section Xi Requirements for
Containment Building Inspections (EPID L-2023-LLR-0061)
8/2/2024
Relief Request
Callaway Plant, Unit No. 1 - Authorization and Safety
Evaluation for Alternative Request C3R-01 (EPID L-2023-LLR-
0061)
8/13/2024
71003
Miscellaneous
Request for Relief from Requirements of ASME BPV Code,
Section XI, Subsection IWL Regarding Examination and
Testing of the Unbonded Post-Tensioning System (Relief
Request C3R-01)
10/26/2023
Miscellaneous
Supplement to Relief Request from Requirements of ASME
BPV Code,Section XI, Subsection IWL Regarding
Examination and Testing of the Unbonded Post-Tensioning
System (Relief Request C3R-01)
2/21/2023
71003
Procedures
Ultimate Heat Sink Retention Pond In-Service Inspection
Callaway Structures Inspection Program
Work Orders
Job
24000980, 24002343, 24503571