ML26016A558
| 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
Shawn Hafen Site Vice President Monticello Nuclear Generating Plant Northern States Power Company, Minnesota 2807 West County Road 75 Monticello, MN 55362-9637
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 cc: Distribution via LISTSERV January 20, 2026 Signed by Szwarc, Dariusz on 01/20/26
Letter to Shawn Hafen from Dariusz Szwarc dated January 20, 2026.
SUBJECT:
MONTICELLO NUCLEAR GENERATING PLANT - INTEGRATED INSPECTION REPORT 05000263/2025004 DISTRIBUTION:
Rodney Clagg RidsNrrDorlLpl3 RidsNrrPMMonticello RidsNrrDroIrib Resource Mohammed Shuaibi Diana Betancourt-Roldan Deborah Piskura Shelbie Lewman Jennifer Dalzell R3-DORS ADAMS Accession Number: ML26016A558
SUNSI Review
Non-Sensitive
Sensitive
Publicly Available
Non-Publicly Available OFFICE RIII NAME DSzwarc:anm DATE 01/20/2026 OFFICIAL RECORD COPY
Enclosure U.S. NUCLEAR REGULATORY COMMISSION Inspection Report Docket Number:
05000263 License Number:
DPR-22 Report Number:
05000263/2025004 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
2
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.
3 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
4 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
5 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.
6 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.
7 DOCUMENTS REVIEWED Inspection Procedure Type Designation Description or Title Revision or Date 215423 RHR Service Water System Prestart Valve Checklist 37 71111.04 Procedures 215434 Emergency Service Water System Prestart Valve Checklist 33 A.308 Cable Spreading Room 16 71111.05 Fire Plans A.315-B No. 11 Diesel Generator Room & No. 11 & No. 12 DG Day Tank Rooms 15 Miscellaneous RQ-SS175 RCIC Leak, Loss of Stator Water Cooling with High Power ATWS 1
71111.11Q Procedures 2300 Reactivity Adjustment 12/20/2025 Procedures FP-WM-IRM01 Integrated Risk Management 27 71111.13 Work Orders WO 700143690 Perform Mechanical PM on V-AC10A Rx Bldg. Main Supply HVAC Unit 01/29/2019 501000089688 MO2013 Motor Pinion Concern 09/10/2024 501000098840 12 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 14 RHRSW Pump Pressure Low During RTS 10/06/2025 Corrective Action Documents 501000105806 14 RSW Pump Low Pressure at B RHR HX 12/05/2025 501000105620 Motor Pinion Inspection Enhancements 11/25/2025 501000105630 MOV Set Screw Not Retained 11/25/2025 501000105656 NRC Question on 7001437650010 Redundant Steps 12/01/2025 71111.15 Corrective Action Documents Resulting from Inspection 501000106124 NRC Question on P202B Maintenance 12/15/2025 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 1
71114.04 Procedures EPLAN02 Emergency Plan Annex 1
8 Inspection Procedure Type Designation Description or Title Revision or Date EPLAN04 Monticello Emergency Action Level (EAL) Technical Basis Document 3
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 15 71151 Miscellaneous MSPI Basis Document 16 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 1
Adverse Condition Monitoring Plan - Vessel Flange Seal Leak Alarm 0
Adverse Condition Monitoring Plan - Vessel Flange Seal Leak Alarm 1
Monticello Station Log 08/01/2025 -
08/22/2025 Miscellaneous ODMI 2508 Type 2 Operation Decision Making Issue Evaluation - Rx Vessel Flange Leak 0
C.6004-A35 Vessel Flange Seal Leak 3
71152A Procedures FP-SC-PE05 Shelf Life Program 12 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 71152S Corrective Action Documents 501000104174 Potential Trend in Rework 10/17/2025
9 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 12/03/2025 Procedures FP-PA-ARP01 CAP Process 68