ML25363A117
| ML25363A117 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 12/30/2025 |
| From: | Robert Ruiz NRC/RGN-III/DORS/RPB1 |
| To: | Mudrick C Constellation Energy Generation, Constellation Nuclear |
| References | |
| IR 2025003 | |
| Download: ML25363A117 (0) | |
Text
Christopher H. Mudrick Senior Vice President Constellation Energy Generation, LLC President and Chief Nuclear Office (CNO)
Constellation Nuclear 200 Energy Way, KSA-3N Kennett Square, PA 19348
SUBJECT:
QUAD CITIES NUCLEAR POWER STATION - INTEGRATED INSPECTION REPORT 05000254/2025003 AND 05000265/2025003
Dear Christopher H. Mudrick:
On September 30, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Quad Cities Nuclear Power Station. On November 20, 2025, the NRC inspectors discussed the results of this inspection with Doug Hild, Site Vice President, and other members of your staff. The results of this inspection are documented in the enclosed report.
Due to the temporary cessation of government operations, which commenced on October 01, 2025, the NRC began operating under its Office of Management and Budget-approved plan for operations during a lapse in appropriations. Consistent with that plan, the NRC operated at reduced staffing levels throughout the duration of the shutdown. However, the NRC continued to perform critical health and safety functions and make progress on other high-priority activities associated with the ADVANCE Act and Executive Order 14300. On November 13, 2025, following the passage of a continuing resolution, the NRC resumed normal operations. However, due to the 43-day lapse in normal operations, the Office of Nuclear Reactor Regulation granted the Regional Offices an extension on the issuance of the calendar year 2025, 3rd quarter integrated inspection reports normally issued by November 15, 2025, to December 31, 2025. The NRC will resume the routine cycle of issuing inspection reports on a quarterly basis beginning with the calendar year 2025, 4th quarter integrated inspection reports, which will be issued 45 days after the 4th quarter ends on December 31, 2025.
No findings or violations of more than minor significance were identified during this inspection.
December 30, 2025
C. Mudrick 2
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, Robert Ruiz, Chief Reactor Projects Branch 1 Division of Operating Reactor Safety Docket Nos. 05000254 and 05000265 License Nos. DPR-29 and DPR-30
Enclosure:
As stated cc w/ encl: Distribution via LISTSERV Signed by Ruiz, Robert on 12/30/25
C. Mudrick 3
Letter to Christopher H. Mudrick from Robert Ruiz dated December 30, 2025.
SUBJECT:
QUAD CITIES NUCLEAR POWER STATION - INTEGRATED INSPECTION REPORT 05000254/2025003 AND 05000265/2025003 DISTRIBUTION:
Rodney Clagg RidsNrrDorlLpl3 RidsNrrPMQuadCities Resource RidsNrrDroIrib Resource Jack Giessner Mohammed Shuaibi Diana Betancourt-Roldan John Pelchat Deborah Piskura Jared Heck Jennifer Dalzell R3-DORS ADAMS Accession Number: ML25363A117
SUNSI Review
Non-Sensitive
Sensitive
Publicly Available
Non-Publicly Available OFFICE RIII RIII NAME NShah:gmp RRuiz DATE 12/30/2025 12/30/2025 OFFICIAL RECORD COPY
Enclosure U.S. NUCLEAR REGULATORY COMMISSION Inspection Report Docket Numbers:
05000254 and 05000265 License Numbers:
DPR-29 and DPR-30 Report Numbers:
05000254/2025003 and 05000265/2025003 Enterprise Identifier:
I-2025-003-0056 Licensee:
Constellation Nuclear Facility:
Quad Cities Nuclear Power Station Location:
Cordova, IL Inspection Dates:
July 01, 2025, to September 30, 2025 Inspectors:
C. Hunt, Senior Resident Inspector E. Kokkinis, Resident Inspector C. Norton, Senior Resident Inspector M. Porfirio, Illinois Emergency Management Agency Approved By:
Robert Ruiz, Chief Reactor Projects Branch 1 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 Quad Cities Nuclear Power Station, 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 Unit 1 began the inspection period at rated thermal power. On September 6, 2025, power was reduced to approximately 20 percent to repair adjustable speed drive and to perform control rod sequence exchange. The unit returned to 100 percent rated thermal power on September 7, 2025. On September 13, 2025, power was reduced to approximately 73 percent to perform control rod sequence exchange. The unit returned to 100 percent rated thermal power on September 14, 2025.
Unit 2 operated at or near rated thermal power for the entire 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 Impending Severe Weather Sample (IP Section 03.02) (1 Sample)
(1)
The inspectors evaluated the adequacy of the overall preparations to protect risk-significant systems from impending severe weather including lightning and thunderstorms on July 10, 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)
Unit 1 diesel generator (DG) during 1/2 DG system planned maintenance and testing on July 17, 2025 (2)
Unit 1B train residual heat removal (RHR) system during 1A RHR pump maintenance and testing on July 18, 2025
4 71111.05 - Fire Protection Fire Area Walkdown and Inspection Sample (IP Section 03.01) (1 Sample)
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 Zone 5.0, Unit 2 turbine building, elevation 595'-0", safe shutdown pump room on August 15, 2025 71111.06 - Flood Protection Measures Flooding Sample (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated internal flooding mitigation protections in the Unit 1 high pressure coolant injection (HPCI) rooms and reactor core isolation cooling (RCIC) rooms on August 13, 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 a Unit 1 planned down-power and single loop operation on September 6, 2025.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
(1)
The inspectors observed and evaluated licensed operator requalification on July 14, 2025.
71111.12 - Maintenance Effectiveness Maintenance Effectiveness (IP Section 03.01) (4 Samples 1 Partial)
The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components (SSCs) remain capable of performing their intended function:
(1)
Unit 1 target rock safety relief valve on July 21, 2025 (2) safe shutdown makeup pump on August 18, 2025 (3) 2A RHR service water pump high pressure seal water orifice on August 21, 2025 (4)
Unit 1 HPCI room cooler on August 28, 2025 (5)
(Partial)
Unit 1 250 VDC [Volts direct current] motor control center 1A cubicles on September 17, 2025
5 71111.13 - Maintenance Risk Assessments and Emergent Work Control Risk Assessment and Management Sample (IP Section 03.01) (4 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) risk management associated with Unit 1B adjustable speed drive and unplanned conditional critical window on July 17, 2025 (2) risk management associated with emergent 1/2 'B' emergency fire pump unplanned unavailability on July 22, 2025 (3) risk management associated with Unit 2B RHR service water unplanned maintenance on August 8, 2025 (4) risk management associated with Unit 1 HPCI turbine inlet supply valve unplanned maintenance on September 5, 2025 71111.15 - Operability Determinations and Functionality Assessments Operability Determination or Functionality Assessment (IP Section 03.01) (5 Samples)
The inspectors evaluated the licensees justifications and actions associated with the following operability determinations and functionality assessments:
(1) operability of the Unit 1 and 1/2 DGs for performing the DG fuel oil transfer pump operability surveillance, QCOS 6600-3 on Unit 2 (2) operability of Unit 1 HPCI with the room cooler inoperable (3) operability of Unit 1 HPCI with leaking cooling water pressure control valve (4) operability of Unit 1 HPCI when the HPCI turbine inlet valve would not open from the control room (5) availability of the safe shutdown makeup pump with the contaminated condensate storage tank suction line isolated and drained 71111.18 - Plant Modifications Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02)
(1 Sample)
The inspectors evaluated the following temporary or permanent modifications:
(1) temporary isolation of the Unit 2 southeast water box from the water box vacuum/venting system to prevent leakage
6 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)
Unit 2 station blackout DG test after scheduled maintenance on August 14, 2025 (2) safe shutdown makeup pump test after breaker and room cooler maintenance on August 21, 2025 (3) 2A RHR service water pump seal line orifices after cleaning and inspection on August 22, 2025 Surveillance Testing (IP Section 03.01) (6 Samples)
(1)
QCOS 6600-41, Unit 1 Emergency Diesel Generator Load Test, on July 7, 2025 (2)
QCOS 2900-01, SSMP [safe shutdown makeup pump] Flow Rate Test, on August 21, 2025 (3)
QCOS 1000-04, RHR Service Water Pump Operability Test, on August 22, 2025 (4)
Unit 2B loop low-pressure coolant injection system non-outage logic test on September 3, 2025 (5)
Unit 2 RCIC pump operability test on September 4, 2025 (6)
Unit 2 standby liquid control pump flow rate test on September 10, 2025 Diverse and Flexible Coping Strategies (FLEX) Testing (IP Section 03.02) (1 Sample)
(1)
FLEX diesel generator 5 test on July 17, 2025 71114.06 - Drill Evaluation Additional Drill and/or Training Evolution (1 Sample)
The inspectors evaluated:
(1) emergency response Team 3 training drill on July 22, 2025 OTHER ACTIVITIES - BASELINE 71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
MS07: High Pressure Injection Systems (IP Section 02.06) (2 Samples)
(1)
Unit 1 (July 1, 2024, through June 30, 2025)
(2)
Unit 2 (July 1, 2024, through June 30, 2025)
7 MS08: Heat Removal Systems (IP Section 02.07) (2 Samples)
(1)
Unit 1 (July 1, 2024, through June 30, 2025)
(2)
Unit 2 (July 1, 2024, through June 30, 2025) 71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02) (1 Sample)
(1)
The inspectors reviewed the licensees corrective action program (CAP) to identify potential trends in the function of the Unit 2 sequence of events recorder (SER) that might be indicative of a more significant safety issue.
INSPECTION RESULTS Observation: Resolution of Degraded Unit 2 Sequence of Events Recorder 71152S The reliability of the Unit 2 sequence of events recorder (SER) was noted in the CAP to have decreased over time, which affected the ability of operators to cut out nuisance alarms. The state of the SER was observed to have created a distraction for the operators when they had to repeatedly acknowledge alarms during routine operations, such as running suppression pool cooling. It was also observed that this condition had the potential to interfere with operator concentration and awareness during plant transients. The licensee had intended to replace the Unit 2 SER during the 2026 refueling outage and put off pursuing short-term resolution.
The inspectors reviewed the CAP history and observed that a slow degradation of the Unit 2 SER began June 27, 2024, when the Unit 2 interface with the SER (referred to as the beta box) disabled the wrong alarm points. Rebooting the SER computer and resetting the SER restored limited function. On December 6, 2024 and January 22, 2025, when addressing alarms, operators found that the beta box was non-functional. Restarting the SER computer provided no immediate relief. On February 4, 2025, the Unit 2 beta box began disabling random alarms and did not allow operators to reenable these alarms or print an alarm summary list. On March 2, 2025, Unit 2s down-power evolution was suspended and delayed for 30 minutes when the Unit 2 SER froze and was not recording inputs. On April 6 and May 7, 2025, Unit 2 SER again froze. Similar failures of the Unit 2 SER were documented on May 19, May 31, June 15, June 16, and July 7, 2025.
After discussions with the inspectors, on August 18, 2025, shift managers elevated visibility of the Unit 2 SER issue by requiring daily reports at the plant status meeting; however, the Unit 2 SER continued to degrade. On September 11, 2025, operators documented that the Unit 2 SER was resetting spuriously several times a shift.
On September 12, 2025, a high impact team (HIT) was formed. The HIT trouble-shot and replaced components in the Unit 2 SER beta box and resolved the issue on September 21, 2025. No subsequent Unit 2 SER issues were identified. The licensee still intends to replace the Unit 2 SER during the 2026 refueling outage.
Although SER issues challenged Unit 2 operators, no violation of regulatory requirements were identified by inspectors because the SER is non-safety related and operators had taken required compensatory actions to monitor/verify plant parameters. Complacent behaviors on the part of the licensee were observed by inspectors through the failure to aggressively
8 address the declining trend in the Unit 2 SER performance. These behaviors were observed to be inconsistent with the NRCs Safety Culture Common Language (NUREG-2165),
Attribute QA.4: Individuals recognize and plan for the possibility of mistakes, latent problems, or inherent risk, even while expecting successful outcomes. This is not, however, a regulatory requirement, and thus is not a violation or finding.
EXIT MEETINGS AND DEBRIEFS The inspectors verified that no proprietary information was retained or documented in this report.
On November 20, 2025, the inspectors presented the integrated inspection results to Doug Hild, Site Vice President, and other members of the licensee staff.
9 DOCUMENTS REVIEWED Inspection Procedure Type Designation Description or Title Revision or Date Corrective Action Documents AR 4879825 Lightning Strike Coincident with Spurious U1 Annunciators 07/08/2025 71111.01 Procedures QCOA 0010-10 Tornado Watch/Warning Severe Thunderstorm Warning, or Severe Winds 35 M-25, Sheet 2 Diagram of Service Air Piping Diesel Generator Air Start 08/25/1998 Drawings M-39, Sheet 3 Diagram of Residual Heat Removal RHR Piping 07/29/1999 QOM 1-1000-03 Unit 1 RHR Valve Checklist (Rack 2201-59B, South RHR Room) 5 QOM 1-1000-04 Unit 1 RHR Valve Checklist (South RHR Room) 13 QOM 1-1000-09 Unit 1 'B' RHR Valve Checklist (Outside 1B RHR Corner Room) 9 71111.04 Procedures QOM 1-6600-1 Unit 1 Diesel Generator Valve Checklist 26 71111.05 Fire Plans FZ 5.0 Unit 2 TB 595'-0" Elev. Safe Shutdown Pump Room 08/2022 Corrective Action Documents Resulting from Inspection AR 4891844 NRC ID: Flood Barrier Readiness 08/20/2025 Miscellaneous QC-PSA-012 Quad Cities Internal Flood Evaluation Summary and Notebook 05/14/2010 71111.06 Procedures QCTS 0810-10 Reactor Building Internal Flood Barrier Surveillance 8
Miscellaneous LOCT-2421 Faulted Tagout/TCV Failure/Circ Water Rupture/LOCA/Blowdown 2
QCOP 0202-21 Unit 1 Reactor Recirculation system Shut Down of One Pump 21 QCOP 202-42 Reactor Recirculation System Startup 27 71111.11Q Procedures QCOS 0202-09 Recirculation Single Loop Operation Outage Report 20 AR 4850594 PSU - QCOS 4700-02 Target Rock System Leak Test 03/30/2025 AR 4891157 0-5799 SSMP AHU Inboard Fan Bearing Degraded 08/19/2025 71111.12 Corrective Action Documents AR 4893750 FI 1-3941 Degraded Root Valves 48H & 48L Packed with Mud 08/28/2025
10 AR 4895640 PMs Have Been Canceled and Need to be Re-Implemented 09/05/2025 Corrective Action Documents WGE 4850594 Work Group Evaluation for IR 4850594: QCOS 4700-02 Target Rock System Leak Test 06/05/2025 Miscellaneous ISSUE-2025-8014 1-0203-3A TR SRV Diaphragm Degradation 06/27/2025 Operability Evaluations AT 4849546-02 Past Functionality for TR SRV 04/24/2025 Procedures QC EPM 0200-06 Inspection and Maintenance of 4kV Vertical Cubicle 31 WO 5047792 Bus 31 Cubicle 1 Inspection 1
71111.12 Work Orders WO 5341414 Inspect/Clean 2A RHR SW High Pressure Pump Seal/Flush Orifices 08/21/2025 AR 4882784 Unexpected Annunciator 901-4 A5, RRCA/ASD Minor Failure 07/17/2025 AR 4884133 1/2 'B' Fire Pump Diesel Overspeed 07/22/2025 AR 4888530 Rec. Alarm 902-3 C-8 RHR Dish Header Hi/Lo Pressure 08/05/2025 AR 4888532 Erroneous RHR Flow Indication 08/05/2025 AR 4888545 RHRSW Leak In 2B RHR Room 08/05/2025 AR 4888633 Erroneous RHR Service Water Flow Indication 08/06/2025 AR 4888635 Erroneous Containment Spray Flow Indication 08/06/2025 Corrective Action Documents AR 4895381 MO 1-2301-3 Not Opening from Control Switch 09/04/2025 4E-1529, Sheet 1 Schematic Diagram High Pressure Coolant Injection System Steam Main Pumps and Condensate Valves AN Drawings 4E-1684C Wiring Diagram Reactor Building 250V DC MCC 1A Part 3 AG QCAN 901-4 A5 RRCS/ASD Minor Failure 9
QCOA 0202-08 Reactor Recirculation Control System Trouble 22 71111.13 Procedures QCOA 0202-09 Reactor Recirculation Adjustable Speed Drive (ASD) Alarm Panel Response 20 AR 4894083 Leak Found on PCV 1-2301-46 08/29/2025 AR 4895381 MO 1-2301-3 Not Opening from the Control Room 09/04/2025 Corrective Action Documents AR 4899548 Relay 1-590-102F Intermittently Chattering 09/21/2025 71111.15 Corrective Action Documents Resulting from Inspection AR 4893894 NRC ID: Loose Insulation U1 HPCI 08/28/2025
11 4E-1529 Schematic Diagram High Pressure Coolant Injection System Steam Main Pumps and Condensate valves AN 4E1466, Sheet 1 Schematic Diagram Reactor Protection System Channel B SCRAM & Auxiliary Trip Relays AH 4E1466, Sheet 3 Schematic Diagram Reactor Protection System CH B SCRAM and Aux Trip Relays AP Drawings M-46, Sheet 1 Diagram of HPCI Piping CF Engineering Evaluations EC 353595 Online HPCI Room Cooler Maintenance and HPCI System Availability 0
OP-AA-108-115 Operability Determinations 28 OP-QC-102-106 Operator Response Time Program at Quad Cities 18 QCOP 2900-01 Safe Shutdown Makeup Pump System Preparation for Standby Operation 42 QCOP 2900-02 Safe Shutdown Makeup Pump Local Operation 33 71111.15 Procedures QCOS 6600-3 Diesel Generator Fuel Oil Transfer Pump Monthly Operability 27 71111.18 Engineering Changes EC 641814 Temporary Isolation of the Southeast Water Box from the Water Box Vacuum/Venting System to Prevent Leakage 0
AR 4841743 N+1Battery Powered Trailer Mover F-20 Error 03/01/2025 AR 4890202 U2 SBO Trouble Alarm 08/13/2025 Corrective Action Documents AR 4894711 2C RHRSW Pump Breaker Has Issues in Test Position 09/02/2025 QCOS 0050-01 FLEX Generator Test 14 QCOS 1000-04 RHR Service Water Pump Operability Test 69 QCOS 1000-44 Unit 2 'B' LPCI and Containment Cooling Modes of RHRS Non-Outage Logic Test 32a QCOS 1100-07 SBLC Pump Flow Rate Test 46 QCOS 1300-05 RCIC Pump Operability Test 67 QCOS 2900-01 SSMP Flow Rate Test 44 QCOS 6600-41 Unit 1 Emergency Diesel Generator Load Test 64 71111.24 Procedures QCOS 6620-10 SBO DG 1(2) Endurance/Margin and Full Load Reject Test 40 Miscellaneous Quad Cities 3Q25 ERO Team 3 Drill 07/22/2025 71114.06 Procedures QOP 5750-24 Technical Support Center Ventilation Emergency Operation 07/22/2025 MSPI Derivation Report Unit 1 MSPI High Pressure Injection System Unavailability Index 09/09/2025 71151 Miscellaneous MSPI Derivation Report Unit 1 MSPI High Pressure Injection System Unreliability Index 09/09/2025
12 MSPI Derivation Report Unit 1 MSPI Heat Removal System Unavailability Index 09/09/2025 MSPI Derivation Report Unit 1 MSPI Heat Removal System Unreliability Index 09/09/2025 MSPI Derivation Report Unit 2 MSPI High Pressure Injection System Unavailability Index 09/09/2025 MSPI Derivation Report Unit 2 MSPI High Pressure Injection System Unreliability Index 09/09/2025 MSPI Derivation Report Unit 2 MSPI Heat Removal System Unreliability Index 09/09/2025 MSPI Derivation Report Unit 2 MSPI Heat Removal System Unreliability Index 09/09/2025 AR 4783718 Unit 2 SER Beta Box Not Functional 06/27/2024 AR 4822173 U2 SER No Longer Printing 12/16/2024 AR 4831611 Unit 2 SER Not Alarming or Printing 01/22/2015 AR 4834541 U2 SER Beta Box Malfunctions 02/14/2025 AR 4841830 U2 SER Frozen during Down-Power 03/02/2025 AR 4867012 U2 SER Fuse F13 Reseated IAW QCOA 0900-01 05/19/2025 AR 4869801 U2 SER Froze/BETA Box Unresponsive 05/31/2025 AR 4873144 U2 SER Not Printing Alarms 06/15/2025 AR 4873384 SER Frozen 06/16/2025 AR 4879121 QGA Alarm Tile Disabled due to Unit 2 SER/Beta Box 07/05/2025 Corrective Action Documents AR 4896928 Update to Unit 2 SER Degradation, MCR Distraction 09/11/2025 71152S Procedures OU-AA-101-1002 High Impact (HIT) Teams 8