IR 05000254/2025003
| 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
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 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
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.
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
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
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
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)
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 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.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Corrective Action
Documents
Lightning Strike Coincident with Spurious U1 Annunciators
07/08/2025
Procedures
QCOA 0010-10
Tornado Watch/Warning Severe Thunderstorm Warning, or
Severe Winds
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)
QOM 1-1000-04
Unit 1 RHR Valve Checklist (South RHR Room)
QOM 1-1000-09
Unit 1 'B' RHR Valve Checklist (Outside 1B RHR Corner
Room)
Procedures
QOM 1-6600-1
Unit 1 Diesel Generator Valve Checklist
Fire Plans
FZ 5.0
Unit 2 TB 595'-0" Elev. Safe Shutdown Pump Room
08/2022
Corrective Action
Documents
Resulting from
Inspection
NRC ID: Flood Barrier Readiness
08/20/2025
Miscellaneous
QC-PSA-012
Quad Cities Internal Flood Evaluation Summary and
Notebook
05/14/2010
Procedures
QCTS 0810-10
Reactor Building Internal Flood Barrier Surveillance
Miscellaneous
LOCT-2421
Faulted Tagout/TCV Failure/Circ Water
Rupture/LOCA/Blowdown
QCOP 0202-21
Unit 1 Reactor Recirculation system Shut Down of One
Pump
QCOP 202-42
Reactor Recirculation System Startup
Procedures
QCOS 0202-09
Recirculation Single Loop Operation Outage Report
PSU - QCOS 4700-02 Target Rock System Leak Test
03/30/2025
0-5799 SSMP AHU Inboard Fan Bearing Degraded
08/19/2025
Corrective Action
Documents
FI 1-3941 Degraded Root Valves 48H & 48L Packed with
Mud
08/28/2025
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
04/24/2025
Procedures
Inspection and Maintenance of 4kV Vertical Cubicle
Bus 31 Cubicle 1 Inspection
Work Orders
Inspect/Clean 2A RHR SW High Pressure Pump Seal/Flush
Orifices
08/21/2025
Unexpected Annunciator 901-4 A5, RRCA/ASD Minor
Failure
07/17/2025
1/2 'B' Fire Pump Diesel Overspeed
07/22/2025
Rec. Alarm 902-3 C-8 RHR Dish Header Hi/Lo Pressure
08/05/2025
Erroneous RHR Flow Indication
08/05/2025
08/05/2025
Erroneous RHR Service Water Flow Indication
08/06/2025
Erroneous Containment Spray Flow Indication
08/06/2025
Corrective Action
Documents
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
Wiring Diagram Reactor Building 250V DC MCC 1A Part 3
AG
QCAN 901-4 A5
RRCS/ASD Minor Failure
QCOA 0202-08
Reactor Recirculation Control System Trouble
Procedures
QCOA 0202-09
Reactor Recirculation Adjustable Speed Drive (ASD) Alarm
Panel Response
Leak Found on PCV 1-2301-46
08/29/2025
MO 1-2301-3 Not Opening from the Control Room
09/04/2025
Corrective Action
Documents
Relay 1-590-102F Intermittently Chattering
09/21/2025
Corrective Action
Documents
Resulting from
Inspection
NRC ID: Loose Insulation U1 HPCI
08/28/2025
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
Drawings
M-46, Sheet 1
Diagram of HPCI Piping
Engineering
Evaluations
Online HPCI Room Cooler Maintenance and HPCI System
Availability
OP-QC-102-106
Operator Response Time Program at Quad Cities
QCOP 2900-01
Safe Shutdown Makeup Pump System Preparation for
Standby Operation
QCOP 2900-02
Safe Shutdown Makeup Pump Local Operation
Procedures
QCOS 6600-3
Diesel Generator Fuel Oil Transfer Pump Monthly Operability
Engineering
Changes
Temporary Isolation of the Southeast Water Box from the
Water Box Vacuum/Venting System to Prevent Leakage
N+1Battery Powered Trailer Mover F-20 Error
03/01/2025
U2 SBO Trouble Alarm
08/13/2025
Corrective Action
Documents
2C RHRSW Pump Breaker Has Issues in Test Position
09/02/2025
QCOS 0050-01
FLEX Generator Test
QCOS 1000-04
RHR Service Water Pump Operability Test
QCOS 1000-44
Unit 2 'B' LPCI and Containment Cooling Modes of RHRS
Non-Outage Logic Test
2a
QCOS 1100-07
SBLC Pump Flow Rate Test
QCOS 1300-05
RCIC Pump Operability Test
QCOS 2900-01
SSMP Flow Rate Test
QCOS 6600-41
Unit 1 Emergency Diesel Generator Load Test
Procedures
QCOS 6620-10
SBO DG 1(2) Endurance/Margin and Full Load Reject Test
Miscellaneous
Quad Cities 3Q25 ERO Team 3 Drill
07/22/2025
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
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
Unit 2 SER Beta Box Not Functional
06/27/2024
U2 SER No Longer Printing
2/16/2024
Unit 2 SER Not Alarming or Printing
01/22/2015
U2 SER Beta Box Malfunctions
2/14/2025
U2 SER Frozen during Down-Power
03/02/2025
U2 SER Fuse F13 Reseated IAW QCOA 0900-01
05/19/2025
U2 SER Froze/BETA Box Unresponsive
05/31/2025
U2 SER Not Printing Alarms
06/15/2025
SER Frozen
06/16/2025
QGA Alarm Tile Disabled due to Unit 2 SER/Beta Box
07/05/2025
Corrective Action
Documents
Update to Unit 2 SER Degradation, MCR Distraction
09/11/2025
Procedures
High Impact (HIT) Teams
8