IR 05000263/2025004
| ML26016A558 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 01/20/2026 |
| From: | Dariusz Szwarc NRC/RGN-III/DORS/RPB3 |
| To: | Hafen S Northern States Power Company, Minnesota |
| References | |
| IR 2025004 | |
| Download: ML26016A558 (0) | |
Text
SUBJECT:
MONTICELLO NUCLEAR GENERATING PLANT - INTEGRATED INSPECTION REPORT 05000263/2025004
Dear Shawn Hafen:
On December 31, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Monticello Nuclear Generating Plant. On January 8, 2026, the NRC inspectors discussed the results of this inspection with you 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, Dariusz Szwarc, Chief Reactor Projects Branch 3 Division of Operating Reactor Safety Docket No. 05000263 License No. DPR-22
Enclosure:
As stated
Inspection Report
Docket Number:
05000263
License Number:
Report Number:
Enterprise Identifier:
I2025004-0058
Licensee:
Northern States Power Company, Minnesota
Facility:
Monticello Nuclear Generating Plant
Location:
Monticello, MN
Inspection Dates:
October 1, 2025, to December 31, 2025
Inspectors:
T. Hartman, Senior Resident Inspector
T. McGowan, Emergency Preparedness Inspector
K. Pusateri, Resident Inspector
J. Robb, Operations Engineer
T. Wingfield, Operations Engineer
Approved By:
Dariusz Szwarc, Chief
Reactor Projects Branch 3
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Monticello Nuclear Generating 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 unit began the inspection period at rated thermal power. On December 22, 2025, the unit was lowered to approximately 55 percent rated thermal power for repairs to a main feedwater pump. On December 24, 2025, the unit returned to rated thermal power and remained at or near 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 onsite 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
71111.04 - 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)division 1 emergency filtration train emergency service water system on October 02, 2025 (2)division 1 residual heat removal service water (RHRSW) on October 30, 2025
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (2 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)fire zones 15 B, C, and D, 11 diesel generator room including 11 and 12 day tank rooms, on October 07, 2025 (2)fire zone 8, cable spreading room, on October 20, 2025
71111.11A - Licensed Operator Requalification Program and Licensed Operator Performance
Requalification Examination Results (IP Section 03.03) (1 Sample)
- (1) The inspectors reviewed and evaluated the licensed operator examination failure rates for the requalification annual operating examination and biennial written examinations administered between the weeks of September 8, 2025, and 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 power reduction for reactor feedwater pump repairs with reactor manual control system challenges on December 20, 2025.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated an NRC exam simulator requalification scenario on October 22, 2025.
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (2 Samples)
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)unplanned entry into a risk informed completion time for an instrument failure in reactor core isolation cooling (RCIC) system on October 12, 2025 (2)emergent change in high-risk plan for reactor building main supply HVAC unit (VAC10A) per WO 700143690
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (4 Samples)
The inspectors evaluated the licensees justifications and actions associated with the following operability determinations and functionality assessments:
(1)14 residual heat removal (RHR) service water pump has low discharge pressure (2)division 2 RHR low pressure coolant injection outboard valve (MO2013) motor pinion concern with no set screw part traceability (3)division 1 RHR discharge to torus outboard valve (MO2006) loose motor pinion (4)12 RHR pump vibrations are in the inservice testing (IST) alert range
71114.04 - Emergency Action Level and Emergency Plan Changes
Inspection Review (IP Section 02.0102.03) (1 Sample)
- (1) The inspectors evaluated the following submitted emergency action level and emergency plan changes:
- EPLAN01, Standard Emergency Plan, Rev. 1
- EPLAN02, Emergency Plan Annex, Rev. 1
- EPLAN04, Monticello Emergency Action Level (EAL) Technical Basis Document, Rev. 3 This evaluation does not constitute NRC approval.
OTHER ACTIVITIES - BASELINE
71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
MS09: Residual Heat Removal Systems (IP Section 02.08) (1 Sample)
- (1) Unit 1 (October 1, 2024, through September 30, 2025)
MS10: Cooling Water Support Systems (IP Section 02.09) (1 Sample)
- (1) Unit 1 (October 1, 2024, through September 30, 2025) 71152A - Annual Follow-up Problem Identification and Resolution
Annual Follow-up of Selected Issues (Section 03.03) (2 Samples)
The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:
(1)safety-related grease expiring prior to use (2)reactor pressure vessel flange inner seal leakage
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 that might be indicative of a more significant safety issue during the week ending December 12, 2025. Since April 1, 2025, the licensee, in accordance with FP-PA-ARP01, CAP Process, has written 36 corrective action documents to evaluate issues that are or could be considered trends. The inspectors did not identify any findings or violations of NRC requirements in the course of their review.
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 8, 2026, the inspectors presented the integrated inspection results to S. Hafen, Site Vice President, and other members of the licensee staff.
- On December 19, 2025, the inspectors presented the Emergency Action Level and emergency plan changes inspection results to B. Carberry, Emergency Preparedness Manager, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
215423
RHR Service Water System Prestart Valve Checklist
Procedures
215434
Emergency Service Water System Prestart Valve Checklist
A.308
Cable Spreading Room
Fire Plans
A.315-B
No. 11 Diesel Generator Room & No. 11 & No. 12 DG
Day Tank Rooms
Miscellaneous
RQ-SS175
RCIC Leak, Loss of Stator Water Cooling with High Power
Procedures
2300
Reactivity Adjustment
2/20/2025
Procedures
FP-WM-IRM01
Integrated Risk Management
Work Orders
Perform Mechanical PM on V-AC10A Rx Bldg. Main
Supply HVAC Unit
01/29/2019
501000089688
MO2013 Motor Pinion Concern
09/10/2024
501000098840
RHR Pump Vibrations Elevated into the Alert Range
During Procedure 025504-IA12
05/15/2025
501000102811
Pinion Gear was Loose on the Motor Shaft During Extent of
Condition Inspection
09/09/2025
501000103587
RHRSW Pump Pressure Low During RTS
10/06/2025
Corrective Action
Documents
501000105806
RSW Pump Low Pressure at B RHR HX
2/05/2025
501000105620
Motor Pinion Inspection Enhancements
11/25/2025
501000105630
MOV Set Screw Not Retained
11/25/2025
501000105656
NRC Question on 7001437650010 Redundant Steps
2/01/2025
Corrective Action
Documents
Resulting from
Inspection
501000106124
NRC Question on P202B Maintenance
2/15/2025
501000094114
MNGP Ops Memo 2405 vs. EPFAQ 201804
01/16/2025
501000102376
EPLAN Document Alignment
08/27/2025
501000102591
EPLAN01 Rev 1 Change Summary Incorrect
09/02/2025
501000102592
Emergency Plan Submittal was Late
09/02/2025
501000102731
Documents Not Updated for EPLAN Change
09/05/2025
Corrective Action
Documents
501000103510
EPLAN/EPIP Misalignment
09/30/2025
EPLAN01
Standard Emergency Plan
Procedures
EPLAN02
Emergency Plan Annex
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
EPLAN04
Monticello Emergency Action Level (EAL) Technical Basis
Document
MSPI Margin Report - MS0608, 4Q243Q25
10/28/2025
MSPI Derivation Reports; Cooling Water, Residual Heat
Removal; Unavailability Index; Unit 1
10/1/2024 -
09/30/2025
MSPI Derivation Reports; Cooling Water, Residual Heat
Removal; Unreliability Index; Unit 1
10/1/2024 -
09/30/2025
MSPI Basis Document
71151
Miscellaneous
MSPI Basis Document
501000012629
SR Grease Expiration Concern
05/30/2018
501000012696
SR Grease Past Expiration Date
06/01/2018
501000098976
Vessel Flange Seal Leak
05/19/2025
501000101552
Vessel Flange Leakage 4A-35 Received
08/02/2025
501000102090
Seal Leak Parameter Action Level Reached
08/17/2025
501000102132
Flange Seal Leak Growing
08/18/2025
501000102188
Condition Update for WO 70055219
08/21/2025
Corrective Action
Documents
501000102290
ACMP Threshold Value Updated
08/22/2025
Engineering
Evaluations
608000000211
Grease Used in Safety-Related Equipment Exceeded Shelf
Life
Adverse Condition Monitoring Plan - Vessel Flange Seal
Leak Alarm
Adverse Condition Monitoring Plan - Vessel Flange Seal
Leak Alarm
Monticello Station Log
08/01/2025 -
08/22/2025
Miscellaneous
ODMI 2508
Type 2 Operation Decision Making Issue Evaluation - Rx
Vessel Flange Leak
C.6004-A35
Vessel Flange Seal Leak
Procedures
Shelf Life Program
501000100107
NOS Adverse Trend: Maintenance PU&A
06/18/2025
501000101787
Trend in Work H Rule CAPS
08/08/2025
501000102721
Trend CAP - Door Issues at MNGP
09/05/2025
Corrective Action
Documents
501000104174
Potential Trend in Rework
10/17/2025
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
501000105262
Trend in CAP Closure and Causal Eval
11/13/2025
501000105615
Trend in CAP Behaviors
11/25/2025
Miscellaneous
MT POT TREND Keyword Search 04012025 to 11302025
2/03/2025
Procedures
FP-PA-ARP01
CAP Process
68