IR 05000483/2025004
| ML26020A112 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 01/23/2026 |
| From: | Ami Agrawal NRC/RGN-IV/DORS/PBB |
| To: | Karenina Scott Union Electric Co |
| References | |
| IR 2025004 | |
| Download: ML26020A112 (0) | |
Text
January 23, 2026
SUBJECT:
CALLAWAY PLANT - INTEGRATED INSPECTION REPORT 05000483/2025004
Dear Kent Scott:
On December 31, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at the Callaway Plant. On January 6, 2026, the NRC inspectors discussed the results of this inspection with J. Morton, Supervising Engineer, 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, Ami N. Agrawal, Chief Reactor Projects Branch B 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-2025-004-0004
Licensee:
Union Electric Company
Facility:
Callaway Plant
Location:
Steedman, MO
Inspection Dates:
October 1 to December 31, 2025
Inspectors:
N. Brown, Senior Resident Inspector
J. Ellegood, Senior Resident Inspector
Approved By:
Ami N. Agrawal, Chief
Reactor Projects Branch B
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at the 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.
PLANT STATUS
The Callaway Plant began the inspection period at rated thermal power. On November 12, 2025, the licensee entered a forced outage due to secondary chemistry exceeding allowable limits following an inadvertent actuation of the auxiliary feedwater system. The unit was taken to Mode 5 where it remained until November 25 when plant startup was commenced. The plant was brought critical on November 29, the main generator was synchronized to the grid on November 30, and full power operations resumed on December 2. The plant remained at rated thermal power for the remainder of the inspection period.
INSPECTION SCOPES
Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs 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 IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors performed activities described in IMC 2515, Appendix D, Plant Status, observed risk significant activities, and completed on-site portions of IPs. The inspectors 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.
REACTOR SAFETY
71111.01 - Adverse Weather Protection
Seasonal Extreme Weather Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated readiness for seasonal extreme weather conditions prior to the onset of cold temperatures on October 29, 2025.
71111.04 - Equipment Alignment
Partial Walkdown Sample (IP Section 03.01) (2 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
(1)engineered safety features train B switchgear room HVAC on December 10, 2025 (2)component cooling water train B on December 17, 2025
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (3 Samples)
The inspectors evaluated the implementation of the fire protection program by conducting a walkdown and performing a review to verify program compliance, equipment functionality, material condition, and operational readiness of the following fire areas:
(1)upper cable spreading room on October 15, 2025 (2)component cooling water train A and B pump and heat exchanger area, Fire Area A-16, Rooms 1401 and 1406 on October 20, 2025 (3)electrical penetration rooms A and B, Fire Areas A-17 and A-18, Rooms 1409 and 1410 on October 20, 2025
71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Performance in the Actual Plant/Main Control Room (IP Section 03.01) (1 Sample)
- (1) The inspectors observed and evaluated licensed operator performance in the control room during scheduled surveillances on October 3, 2025.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated continuing license training on October 21, 2025.
71111.12 - Maintenance Effectiveness
Maintenance Effectiveness (IP Section 03.01) (4 Samples)
The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components remain capable of performing their intended function:
- (1) Cycle 26 maintenance rule a(3) assessment (2)essential service water train A planned maintenance outage on October 18, 2025 (3)engineered safety features switchgear room HVAC maintenance on December 12, 2025 (4)component cooling water train A on December 18, 2025
Quality Control (IP Section 03.02) (1 Sample)
The inspectors evaluated the effectiveness of maintenance and quality control activities to ensure the following structure, systems or component remains capable of performing its intended function:
- (1) BB8157 A and B controller replacements
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (1 Sample)
The inspectors evaluated the accuracy and completeness of risk assessments for the following planned and emergent work activities to ensure configuration changes and appropriate work controls were addressed:
(1)essential service water A planned maintenance outage on October 15, 2025
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (3 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
(1)power range nuclear instrument SEN0044 on October 7, 2025 (2)residual heat removal pump train B on October 9, 2025 (3)emergency diesel generator A on November 6, 2025
71111.20 - Refueling and Other Outage Activities
Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated forced outage 78 on November 12 through December 4, 2025.
71111.24 - Testing and Maintenance of Equipment Important to Risk
The inspectors evaluated the following testing and maintenance activities to verify system operability and/or functionality:
Post-Maintenance Testing (PMT) (IP Section 03.01) (3 Samples)
(1)essential service water train A on October 18, 2025 (2)auxiliary feedwater system after forced outage 78 on November 29, 2025 (3)engineered safety features train A switchgear room HVAC on December 12, 2025
Inservice Testing (IST) (IP Section 03.01) (2 Samples)
(1)residual heat removal train B inservice test on September 12, 2025
- (2) turbine-driven auxiliary feedwater pump on October 27, 2025
Diverse and Flexible Coping Strategies (FLEX) Testing (IP Section 03.02) (1 Sample)
(1)flex diesel generator checks on September 29, 2025
71114.06 - Drill Evaluation
Additional Drill and/or Training Evolution (1 Sample)
The inspectors evaluated:
- (1) 2025 annual ERO drill on November 20, 2025
OTHER ACTIVITIES - BASELINE
71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
IE01: Unplanned Scrams per 7000 Critical Hours Sample (IP Section 02.01) (1 Sample)
- (1) October 1, 2024, through September 30, 2025
IE03: Unplanned Power Changes per 7000 Critical Hours Sample (IP Section 02.02) (1 Sample)
- (1) October 1, 2024, through September 30, 2025
IE04: Unplanned Scrams with Complications (USwC) Sample (IP Section 02.03) (1 Sample)
- (1) October 1, 2024, through September 30, 2025
MS07: High Pressure Injection Systems (IP Section 02.06) (1 Sample)
- (1) July 1, 2024, through June 30, 2025
MS09: Residual Heat Removal Systems (IP Section 02.08) (1 Sample)
- (1) July 1, 2024, through June 30, 2025 71152A - Annual Follow-up Problem Identification and Resolution
Annual Follow-up of Selected Issues (Section 03.03) (1 Sample)
The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:
(1)
- fire water system
71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02) (1 Sample)
- (1) The inspectors reviewed the licensees corrective action program to identify potential trends in human performance that might be indicative of a more significant safety issue with emphasis on human performance errors during maintenance activities. The inspectors sampled a population of condition reports during the period of July 1 to December 31, 2025. Based on the samples reviewed, the inspectors identified seven instances where mispositioning occurred during maintenance activities and one example of late technical specification entry. While degradation was apparent in the implementation of the licensees human performance program, the licensees organization successfully identified these degradations before any harmful events occurred. The licensee independently identified this human performance trend, condition report 202506087 and condition report 202504781, and is taking appropriate actions to address the degraded conditions that were encountered during the inspection period.
71153 - Follow-Up of Events and Notices of Enforcement Discretion
Personnel Performance (IP Section 03.03) (1 Sample)
- (1) The inspectors evaluated an inadvertent auxiliary feedwater actuation and the licensees response on November 12, 2025.
Reporting (IP Section 03.05) (1 Sample)
The inspectors evaluated the following licensees event reporting determinations to ensure it complied with reporting requirements:
- (1) inadvertent auxiliary feedwater actuation on November 13,
2025 INSPECTION RESULTS
No findings were identified.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On January 6, 2026, the inspectors presented the integrated inspection results to J. Morton, Supervising Engineer, Regulatory Affairs and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Corrective Action
Documents
Condition Reports
2506430, 202506485
Procedures
OTS-ZZ-00007
Plant Cold Weather
Work Orders
Jobs
24512302, 24511862
Checklist 1
OTN-GK-00001
Checklist 1
OTN-GK-00001
Checklist 2
Procedures
OTN-GK-00001
Checklist 3
Calculations
KC-133
Fire Safety Analysis Calculation: KC-133 Fire Area: C-22
Upper Cable Spreading Room
and 4
Miscellaneous
Fire Preplan Manual
OTO-KC-00001,
Addendum A-16
Auxiliary Building 2026' - General Area
OTO-KC-00001,
Addendum A-17
Auxiliary Building 2026' - South Electrical Penetration Room
OTO-KC-00001,
Addendum A-18
Auxiliary Building 2026' - North Electrical Penetration Room
Procedures
OTO-KC-00001,
Addendum C-22
Control Building 2073' Upper Cable Spreading Room
LOCT 25-4 S-2
Control Room
Logs
10/03/2025
Miscellaneous
Training Plan
T61.0810 8
Procedures
Centrifugal Charging Pump B Inservice Test - Group B
Work Orders
Jobs
25509382
Calculations
GK-35
Determination of Allowable Number of Plugged Condenser
Tubes in SGK05A/B
Corrective Action
Documents
Condition Reports
2506181, 202506185, 202506178, 202506244,
2506252, 202507316, 202507319
Maintenance Rule Periodic Assessment for Cycle 26
Miscellaneous
Maintenance Rule Periodic Assessment for Cycle 25
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Request for
Resolution
160775, 240255
EDP-ZZ-04600
Engineering Change Control
Procedures
ETP-ZZ-03050
Aging Management of Loss of Coating or Lining Integrity for
Internal Coatings
Work Orders
Jobs
16005247, 22509549, 24504980, 21504015, 24506069,
23500343, 24507347, 24506050, 24508677, 23500344,
245006113
Miscellaneous
Risk Informed Completion Time RICT-2025-05
Procedures
APA-ZZ-00315
Risk Management Programs
Calculations
ARC-1589
Analysis of EDG System for Replacement of Valves
KJV0820 A & B
Corrective Action
Documents
Condition Reports
2505415, 202505687, 202506110, 202505465,
2506648
Drawings
M-22KJ03
Piping and Instrumentation Diagram Standby Diesel
Generator A Lube Oil System
Work Orders
Jobs
255002751, 25507116, 25507851
Corrective Action
Documents
Condition Reports
2506942, 202506860, 202506893, 202506848,
2506849
OTG-ZZ-00001
Plant Heatup Cold Shutdown to Hot Standby
OTG-ZZ-00002
Reactor Startup - IPTE
Procedures
OTG-ZZ-00003
Plant Startup Hot Zero Power to 30% Power - IPTE
Corrective Action
Documents
Condition Reports
2507352, 202505465, 202506456
OSP-AL-P00002
Turbine Driven Auxiliary Feedwater Pump Inservice Test -
Group B
Procedures
ESW Train A Inservice Test
Work Orders
Jobs
24506069, 25000814, 24506648, 24506058, 25502751,
25507116, 25507851, 24504980, 25511491, 25512379,
25509427, 24508790, 22510214
Miscellaneous
Drill Guide
25 Annual ERO Drill November 13, 2025, to December
18, 2025
Procedures
EIP-ZZ-00101
Classification of Emergencies
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
EIP-ZZ-00101,
Addendum 2
Emergency Action Level Technical Bases Document
Safety Injection Performance Indicator Data Sheets 7/1/2024
through 6/30/2025
Unplanned Scrams per 7000 Critical Hours Performance
Indicator Data Sheets 10/1/2024 through 9/30/2025
Unplanned Scrams with Complications Performance
Indicator Data Sheets 10/1/2024 through 9/30/2025
Unplanned Power Changes per 7000 Critical Hours
Performance Indicator Data Sheets 10/1/2024 through
9/30/2025
71151
Miscellaneous
Residual Heat Removal System Performance Indicator Data
Sheets 7/1/2024 through 6/30/2025
Calculations
KC-43
Code Compliance Evaluation NFPA-805, Performance
Based Standard for Fire Protection for Light Water Reactor
Electrical Generation Plants
Corrective Action
Documents
Condition Reports
2503755, 202503613, 202506133, 202506237
APA-ZZ-00700
APA-ZZ-00703
Fire Protection Operability Criteria and Surveillance
Requirements
Procedures
EDP-ZZ-01101
Fire Protection Monitoring Program
Work Orders
Jobs
25002452, 25003998
OTG-ZZ-00005
Plant Shutdown 20% Power to Hot Standby
OTO-AC-00002
Turbine Vibrations
OTO-MA-00008
Rapid Load Reduction
Procedures
OTO-SA-00001
ESFAS Verification and Restoration
46