IR 05000373/2025002
| ML25223A298 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 08/11/2025 |
| From: | Robert Ruiz NRC/RGN-III/DORS/RPB1 |
| To: | Rhoades D Constellation Energy Generation |
| References | |
| IR 2025002 | |
| Download: ML25223A298 (1) | |
Text
SUBJECT:
LASALLE COUNTY STATION - INTEGRATED INSPECTION REPORT 05000373/2025002 AND 05000374/2025002
Dear David Rhoades:
On June 30, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at LaSalle County Station. On July 9, 2025, the NRC inspectors discussed the results of this inspection with John VanFleet, Site Vice President, 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, Robert Ruiz, Chief Reactor Projects Branch 1 Division of Operating Reactor Safety Docket Nos. 05000373 and 05000374 License Nos. NPF-11 and NPF-18
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000373 and 05000374
License Numbers:
Report Numbers:
05000373/2025002 and 05000374/2025002
Enterprise Identifier:
I-2025-002-0055
Licensee:
Constellation Nuclear
Facility:
LaSalle County Station
Location:
Marseilles, IL
Inspection Dates:
April 01, 2025, to June 30, 2025
Inspectors:
M. Abuhamdan, Reactor Inspector
J. Benjamin, Senior Resident Inspector
J. Hoang, Reactor Technology Instructor
R. Zuffa, Illinois Emergency Management Agency
Approved By:
Robert Ruiz, Chief
Reactor Projects Branch 1
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at LaSalle County 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
Type Issue Number Title Report Section Status LER 05000373/2024-004-01 LER 2024-004-01,
Supplement to Emergency Diesel Generator Auto-Start and Load due to Loss of System Auxiliary Transformer 71153 Closed
PLANT STATUS
Unit 1 began the inspection period at rated thermal power. On April 4, 2025, the unit down powered to approximately 60 percent to perform a reactor control rod pattern adjustment and main turbine control valve testing. The unit returned to full power on April 7, 2025. On June 28, 2025, the unit derated to approximately 90 percent power to ensure adequate main condenser vacuum margin during hot weather conditions coupled with degraded main condenser performance. The unit operated at approximately 90 to 95 percent for the remainder of the inspection period.
Unit 2 began the inspection period at rated thermal power. On May 17, 2025, the unit down powered to approximately 76 percent to perform control rod testing. The unit returned to full power on May 18, 2025, and operated at full power for the remainder of the cycle.
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)station summer readiness: Unit 1 main condenser performance and Unit 2A train emergency diesel generator (EDG) jack water heat exchanger
71111.04 - Equipment Alignment
Partial Walkdown Sample (IP Section 03.01) (3 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
- (1) Unit Common EDG following 2-year planned preventative maintenance out of service on May 9, 2025
- (2) Unit 1 residual heat removal (RHR) service water system following system outage window on June 5, 2025
- (3) Unit 1 switchgear heat removal system (VX) on June 9, 2025
Complete Walkdown Sample (IP Section 03.02) (1 Sample)
The inspectors evaluated system configurations during complete walkdowns of the following systems/trains:
- (1) Unit 2 hardened containment vent system (HCVS) on June 11, 2025
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (7 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 Zone (FZ) 3H4, reactor building, elevation 694'-6", Unit 2 reactor core isolation cooling (RCIC)/low-pressure core spray (LPCS) cubicle on June 3, 2025
- (2) FZ 4E2, auxiliary building, elevation 731'-0", Unit 2 auxiliary equipment room on June 4, 2025
- (3) FZ 2I, reactor building, elevation 673'-4", Unit 1 LPCS/RCIC pump cubicle on June 4, 2025
- (4) FZ 4D3, auxiliary building, elevation 749'-0", Unit 1 electrical equipment room on June 4, 2025
- (5) FZ 4D4, auxiliary building, elevation 749'-0", Unit 2 electrical equipment room on June 4, 2025
- (6) FZ 2E, reactor building, elevation 761'-0", Unit 1 general area on June 5, 2025
- (7) FZ 3F, reactor building, elevation 740'-0", Unit 2 general area on June 6, 2025
71111.06 - Flood Protection Measures
Flooding Sample (IP Section 03.01) (2 Samples)
The inspectors evaluated internal flooding mitigation protections in the:
- (1) Unit 1 AB core standby cooling system (CSCS) pump rooms on June 16, 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 ascension following an unplanned downpower due to high condenser backpressure on June 30, 2025.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated an out-of-the-box training activity on April 22, 2025.
71111.12 - Maintenance Effectiveness
Maintenance Effectiveness (IP Section 03.01) (3 Samples)
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 2A train EDG
- (2) Action Request (AR) 4846342, Rising 2A Reactor Recirculation Pump #2 Seal Pressure Trend
- (3) Unit 2A and 'B' trains EDG cooling water pumps
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (5 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)elevated Unit 1 risk on April 1, 2025, during division 1 work window with RHR system and low-pressure coolant injection inoperable (2)elevated Unit 2 risk on April 8, 2025, during Unit 2B train RHR system planned work window (3)elevated Unit 2 risk on April 21, 2025, during Unit 2 division 3 125 Vdc battery performance testing (4)elevated Unit 1 and Unit 2 risk from May 5, 2025, through May 7, 2025, during unit Common EDG planned work window (5)elevated Unit 2 risk from May 19, 2025, through May 20, 2025, during Unit 2 division 3 work window
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (8 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
- (1) AR 4853964, MOV [motor-operated valve] 2E12-F003B As-Found Under Thrust
- (2) AR 4846342, Rising 2A Reactor Recirculation Pump Seal #2 Adverse Trend
- (3) AR 4857391, 'B' Diesel-Driven Fire Pump Failure to Start on Remote Start Signal from the Main Control Room
- (4) AR 4861597, Unit 1 'B' Train Residual Heat Removal Heat Exchange Service Water Side Through Wall Leak
- (5) AR 4861260, LOA-WL-001 Entry Due to Low Lake Level
- (6) AR 4868809, Unit 2 Reactor Core Isolation Cooling Water Pump Suction Pressure Higher Than Normal
- (7) AR 4868178, U1 RBM [rod-block monitor] Recorder Reading Low
- (8) AR 4875675, ADS [automatic depressurization system) Valve Solenoid Lights Out 2B21C-S013A (Continuity Lights on Panel 2H13-P628)
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) (5 Samples)
- (1) Unit Common 'B' train diesel driven fire pump after upgrade during the week of February 3, 2025
- (2) Unit 1B train RHR service water leak repair on May 4, 2025
- (3) Unit Common EDG cooling water pump planned maintenance on May 7, 2025
- (4) Unit Common EDG 2-year maintenance work on May 7, 2025
- (5) Unit 2 division 3 work window May 19 through May 20, 2025
Surveillance Testing (IP Section 03.01) (5 Samples)
- (1) Work Order (WO) 4745806, Motor Operated Valve 2E12-F003B Diagnostic Testing
- (2) Unit 2 division 3 125 Vdc battery performance testing on April 21, 2025
- (3) Unit 1B train EDG run on April 24, 2025
- (4) Unit 1 division 2 RHR service water system operability and inservice testing on June 1, 2025
- (5) Unit 1 RHR 'B' train pump operability on June 27, 2025
Inservice Testing (IST) (IP Section 03.01) (1 Sample)
- (1) Unit 1 RCIC valve inservice test on June 10, 2025
71114.06 - Drill Evaluation
Required Emergency Preparedness Drill (1 Sample)
- (1) April 18, 2025, drill and exercise performance (DEP) drill
Additional Drill and/or Training Evolution (1 Sample)
The inspectors evaluated:
- (1) April 24, 2025, DEP drill
OTHER ACTIVITIES - BASELINE
===71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
BI02: RCS Leak Rate Sample (IP Section 02.11)===
- (1) Unit 1 (April 1, 2024, through March 31, 2025)
- (2) Unit 2 (April 1, 2024, through March 31, 2025)
71152A - Annual Follow-Up Problem Identification and Resolution Annual Follow-Up of Selected Issues (Section 03.03)
The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:
- (1) AR 4853657, Second Fuel Defect Suppressed at LaSalle
- (2) AR 4849266, 2A RR [reactor recirculation] Pump Seal Cavity #2 Pressure Trend
- (3) AR 4867317, Rosemount Transmitters Static Shift Concern
71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02)
- (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. No potential adverse trends were identified.
71153 - Follow Up of Events and Notices of Enforcement Discretion Event Report (IP Section 03.02)
The inspectors evaluated the following licensee event reports (LERs):
- (1) LER 05000373/2024-004-01, Supplement to Emergency Diesel Generator Auto-Start and Load due to Loss of System Auxiliary Transformer (Agencywide Document Access and Management System (ADAMS) Accession No. ML24235A178). The inspectors determined that the cause of the condition described in the LER was not reasonably within the licensees ability to foresee and correct and therefore was not reasonably preventable. No performance deficiency nor violation of NRC requirements was identified. This LER is closed.
INSPECTION RESULTS
No findings were identified.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified that no proprietary information was retained or documented in this report.
- On July 9, 2025, the inspectors presented the integrated inspection results to John VanFleet, Site Vice President, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Procedures
LOS-ZZ-A2
Preparation for Winter Summer Operation
U1 Div 1 Supply Fan Trip
05/13/2021
Corrective Action
Documents
U1 Div 1 VX Abnormal Noise
04/16/2025
Schematic Diagram Hardened Containment Vent System
(HCVS)
A
Schematic Diagram Hardened Containment Vent System
(HCVS)
A
M-138, Sheet 3
P&ID Primary Containment Vent and Purge
B
M-5092, Sheet 1
Logic Block Diagram Primary Containment Vent and Purge
System "PC"
G
M-959, Sheet 4
Primary Containment and Reactor Vessel Isolation Piping
System
A
Drawings
P&ID M-134
CSCS Equipment Cooling Water System
BH
LOP-DG-03M
Unit 0 Diesel Generator Mechanical Checklist
LOP-PC-04E
Unit 2 Hardened Containment Vent System Electrical
Checklist
LOP-PC-04M
Unit 2 Hardened Containment Vent System Mechanical
Checklist
LOP-RH-05
Operation of the RHR Service Water System
LOP-VX-01
Switchgear Heat Removal System Startup
Procedures
LOP-VX-01E
Unit 1 Switchgear Heat Removal System Electrical Checklist
PFP AUX BLDG
731-0, Fire Zone
4E2
Pre-Fire Plan U2 Auxiliary Equipment Room
PFP AUX BLDG
749-0, Fire Zone
4D3
Pre-Fire Plan U1 Electrical Equipment Room
Fire Plans
PFP AUX BLDG
749-0, Fire Zone
4D4
Pre-Fire Plan U2 Electrical Equipment Room
PFP RX BLDG
673-4, Fire Zone
2I
Pre-Fire Plan U1 LPCS /RCIC Pump Cubicle
PFP RX BLDG
694-6, Fire Zone
3H4
Pre-Fire Plan U2 RCIC/LPCS Cubicle
PFP RX BLDG
740-0, Fire Zone
3F
Pre-Fire Plan U2 General Area & CRD Repair Room
Fire Plans
PFP RX BLDG
761-0, Fire Zone
2E
Pre-Fire Plan U1 General Area & RWCU Pump Cubicles
High Risk Fire Area Identification
LOP-FP-02M
Unit 2 Fire Protection System Mechanical Checklist
Scaffold Installation, Modification, and Removal Request
Process
Control of Transient Combustible Material
Fire Drill Performance
Procedures
OP-LA-201-012-
1001
LaSalle On-Line Fire Risk Management
Corrective Action
Documents
U1 D3 CSCS Sump - Neither Sump Pump Removes Water,
Equipment Deficiency Tag (EDT) 151905
05/18/2025
Engineering
Changes
LaSalle Mitigating Strategies Flood Hazard Assessment
(MSFHA) and Supporting Documents, L-004286
DBD-LS-M11
Topical Design Basis Document Flood Protection
F
LS-PRA-012
LaSalle County Generating Station Probabilistic Risk
Assessment Internal Flood Analysis Volume 1 of 2:
Summary and Notebook
Miscellaneous
LS-PRA-012
LaSalle County Generating Station Probabilistic Risk
Assessment Internal Flood Analysis Volume 2 of 2: Flood
Walkdown Notebook
UFSAR Appendix
J
J.4 Effects of Flooding
UFSAR Chapter
03, Section 04
Figures
UFSAR Chapter
2.4
Hydrologic Engineering
Miscellaneous
UFSAR Chapter
3.4
Water Level (Flood) Design
Plant Barrier Control Program
CC-LA-201-1001
Plant Barrier Control Program Implementation
ER-LA-450
LaSalle Structures Monitoring Program
LOA-FLD-001
Operating Abnormal Procedure - Flooding
Procedures
TRM 3.5.a
ECCS Corner Room Watertight Doors
Miscellaneous
LORT Simulator
Scenario - April
2, 2025
LORT Training Performed on April 22, 2025 in Simulator
Procedures
REMA L1C21-03
Reactivity Maneuver LaSalle Unit 1 Cycle 21-03
06/30/2025
2A DG Cooling Water Strainer Found Continuously
Backwashing
2/23/2023
LOS-DG-M1 DG Engine Cooling Water to Oil Cooler Limit
03/13/2023
2PM01J-B206 2A DG Trouble Alarm
04/01/2023
2A DG Starting Air Pressure PPC D825 Alarm
04/13/2023
2A DG CWP d/p Outside Surveillance Criteria
04/15/2023
2A DG CWP d/p Outside Surveillance Criteria
04/15/2023
2A DG Cooling Water Strainer DP High Alarm
06/07/2023
2A DG Exciter Diode Replacement
10/16/2024
Corrective Action
Documents
Raising Pressure Trend on RR Pump Seals
03/18/2025
Maintenance Rule Functions - Safety Significance
Classification
Exelon Maintenance Rule Process Map
Maintenance Rule Implementation Per NEI 18-10
Maintenance Rule 18-10 Failure Definition
Procedures
Maintenance Rule - (A)(1) and (A)(2) Requirements
Maintenance Rule 18-10 - Expert Panel Roles and
Responsibilities
Procedures
Maintenance Rule Support
Work Orders
Pump Seal
Issues
2A Reactor Recirculation Pump Seal Cavity #2 Adverse
Pressure Trend
03/26/2025
Nuclear Risk Management Process
Risk Management Documentation
On-Line Risk Management
Integrated Risk Management
Operations On-Line Fire Risk Management
OP-LA-201-012
LaSalle On-Line Fire Risk Management
Procedures
On-Line Risk Management and Assessment
During LIS-NR-105B, Found RBM 'B' Not Functioning
Properly
04/30/2025
MOV 2E12-F003B As-Found Underthrust
04/07/2025
'B' DFP Failure to Start on a Remote Start Signal
04/15/2025
Through Wall Leak, WS Side of Outlet Piping of U1 B RHR
04/29/2025
U1 RBM Recorder Reading Low
05/23/2025
U2 RCIC Pump Suction Pressure Indicated High
05/28/2025
Corrective Action
Documents
ADS Valve Solenoid Lights Out 2B21C-S013A
06/24/2025
Corrective Action
Documents
Resulting from
Inspection
Raising Pressure Trend on RR Pump Seals
03/18/2025
Drawings
Schematic Diagram Auto Depressurization System NB B21C
Part 7
R
LOA-WL-001
River Screen House and Lake Abnormal
Technical Specification Compliance
Operability Determinations (CM-1)
Procedures
Control Rod Block Instrumentation
06/12/2025
Perform EQ Inspection and Votes Test
04/07/2025
Work Orders
U1 B RBM Recorder Indication Erratic and Not Normal
06/12/2025
OP-AA-102-107-
1001
Operations On-Line Work Management
On-Line Work Control Process
Procedures
Work Screening and Processing
MOV 2E12-F000B VOTES Diagnostic Testing
04/07/2026
Disassemble, Inspect 0 DG Heat Exchanger
05/05/2025
Unit 2 Division 3 Battery Charger Inspection and Cleaning
05/25/2025
Unit 2 Division III 125VDC Battery Performance Testing
04/21/2025
1B DG 24-HR Run Surveillance
04/24/2025
LOS-RH-Q1 1B RHR WS Operability & Inservice Testing
06/26/2025
LOS-RI-Q1 U1 RCIC Valves
06/10/2025
LOS-RH-Q1 1B RHR Att. 1B - Unit 1 RHR B Quarterly
Surveillance Run
06/27/2025
Work Orders
1B RHR-WS Leak Repair and Drain
05/01/2025
April 18, 2025 EP
Drill Package
Drill Package 4/18/2025
Miscellaneous
April 25, 2025
LaSalle DRP Drill
Package
DEP Drill 4/25/2025
71151
Procedures
Exelon Nuclear Performance Monitoring and Management
Implementation Guide
Calculations
Average Power Range Monitor (APRM), Rod Block Monitor
(RBM), and Recirculation Flow Monitor (RFM) Bistable Loop
Accuracy for Rod Block and Scram Functions
2A RR Pump Seal Cavity #2 Pressure Trend
03/27/2025
Second Fuel Defect Suppressed at LaSalle
04/06/2025
RM - Second Fuel Defect Suppressed in LaSalle Unit 1
04/06/2025
Corrective Action
Documents
Pressure Transmitter Static Shift Concern
05/20/2025
Engineering
Evaluations
NES-EIC-20.04
Analysis of Instrument Channel Setpoint and Instrument
Loop Accuracy
07/18/2011
Miscellaneous
R369-0297
Binder J-0223
Rosemont Transmitters
Procedures
LIS-RR-101A
Unit1 Recirculation Flow Converter A Calibration
LIS-RR-201A
Recirculation Flow Converter A Calibration
BWR Fuel Conditioning
BWR Reactivity Maneuver Guidance
Corrective Action Program (CAP) Procedure
Replace Electrolytic Capacitors in ABB Flow Units
2/19/2025
Work Orders
Recirculation Flow Converter 'A' Calibration
01/15/2025
Operations Trending in Human Performance
04/28/2023
Operations Trend in Communications
05/25/2023
Maintenance Trend: MMD Attention to Detail
06/12/2023
Operations Trend - Place Keeping Behaviors
06/14/2023
Trend in Self-Check Behaviors
08/02/2023
Ops Trend: Attention to Detail Less than Adequate
10/19/2023
Maintenance Trend in Maintenance Work Preparations
11/22/2023
Trend in Control of CDA
2/11/2023
Emerging Trend - At Risk Safety Behaviors
2/22/2024
Corrective Action
Documents
Operations MRM Trend IR
04/08/2025