ML25346A020
| ML25346A020 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 12/12/2025 |
| From: | Dariusz Szwarc NRC/RGN-III/DORS/RPB3 |
| To: | Mudrick C Constellation Energy Generation |
| References | |
| IR 2025003 | |
| Download: ML25346A020 (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:
BYRON STATION - INTEGRATED INSPECTION REPORT 05000454/2025003 AND 05000455/2025003
Dear Christopher H. Mudrick:
On September 30, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Byron Station. On December 10, 2025, the NRC inspectors discussed the results of this inspection with Harris Welt, 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 NRC-identified or self-revealing findings were identified during this inspection.
A licensee-identified violation which was determined to be of very low safety significance is documented in this report. We are treating this violation as a non-cited violation (NCV) consistent with Section 2.3.2 of the Enforcement Policy.
December 12, 2025
C. Mudrick 2
If you contest the violation or the significance or severity of the violation documented in this inspection report, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region III; the Director, Office of Enforcement; and the NRC Resident Inspector at Byron Station.
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 Nos. 05000454 and 05000455 License Nos. NPF-37 and NPF-66
Enclosure:
As stated cc w/ encl: Distribution via LISTSERV Signed by Szwarc, Dariusz on 12/12/25
SUNSI Review
Non-Sensitive
Sensitive
Publicly Available
Non-Publicly Available OFFICE RIII NAME DSzwarc:anm DATE 12/12/2025
Enclosure U.S. NUCLEAR REGULATORY COMMISSION Inspection Report Docket Numbers:
05000454 and 05000455 License Numbers:
NPF-37 and NPF-66 Report Numbers:
05000454/2025003 and 05000455/2025003 Enterprise Identifier:
I-2025-003-0057 Licensee:
Constellation Nuclear Facility:
Byron Station Location:
Byron, IL Inspection Dates:
July 01, 2025, to September 30, 2025 Inspectors:
N. Bolling, Resident Inspector T. Hooker, Health Physicist M. Learn, Team Leader T. Ospino, Resident Inspector C. Padilla, Senior Resident Inspector 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 Byron 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. A licensee-identified non-cited violation is documented in report section: 71111.15.
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 and remained at or near full power throughout the remainder of the inspection period.
Unit 2 began the inspection period at rated thermal power and remained at or near full power throughout 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 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 71111.04 - 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) partial walkdown of the 1A emergency diesel generator (EDG) on July 9, 2025 (2) partial walkdown of the 1A auxiliary feedwater train prior to other train work on July 17, 2025 71111.05 - Fire Protection Fire Brigade Drill Performance Sample (IP Section 03.02) (1 Sample)
(1) observation and evaluation of the stations fire brigade during an announced fire drill on July 15, 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) observation of various activities involving on-watch operations crews in the main control room during the week ending September 5, 2025
4 Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
(1) observation of the performance of a complex casualty graded scenario by a crew of licensed plant operators in the facilitys simulator on August 12, 2025 71111.12 - Maintenance Effectiveness Maintenance Effectiveness (IP Section 03.01) (2 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)
(Partial) maintenance effectiveness review of the 0A essential service water makeup pump (2) review of work practices and challenges generated during the work window associated to the Unit 2B safety injection unplanned maintenance on the week ending July 11, 2025 (3) review of work practices related to the EDG control air system and the maintenance and operability implications for the week ending August 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) review and evaluation of the risk associated with dry cask storage activities, as documented in various work orders (2) risk assessment of the week of September 2, 2025, due to multiple opposite train planned work 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) evaluation of the operability of 1B EDG starting air system, as documented in various action requests (ARs)
(2) evaluation of the operability of 1A EDG after control air loss, as documented in AR 4884396 (3) evaluation of the operability of 2A main steam isolation valve (MSIV) upon discovery of a non-safety-related gauge installed on the safety-related train, as documented in AR 4889796 (4) evaluation of the functionality of four non-safety-related diaphragms installed on the 2A auxiliary feedwater train which is safety related, as documented in various ARs
5 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) (4 Samples)
(1) functional and operational testing of the 2B safety injection train test after failed air test of the 2B SI pump cubicle cooler, as documented in Work Order (WO) 5677654 (2) functional and operational testing of 1B EDG following replacement of 1DG5212B turning gear interlock valve, as documented in WO 5681243 (3) functional and operational testing of DC 211 battery following cell replacement, as documented in WO 5678488 (4) functional and operational testing of 0A SX makeup pump following fuel line repairs, as documented in WO 5535776 Surveillance Testing (IP Section 03.01) (2 Samples)
(1)
BOP IC-3, Moveable Incore Detectors Flux Mapping Procedure, on July 23, 2025 (2) 2BOSR 7.5.4-2, Unit Two Diesel Driven Auxiliary Feedwater Pump Monthly Surveillance, on August 5, 2025 Inservice Testing (IST) (IP Section 03.01) (1 Sample)
(1) 1BOSR 5.5.8.CS.5-2c, Unit One Comprehensive Inservice Testing (IST)
Requirements for Containment Spray Pump 1CS01PB, as documented in WO 5647834 71114.06 - Drill Evaluation Required Emergency Preparedness Drill (1 Sample)
(1) emergency preparedness drill on July 24, 2025 Additional Drill and/or Training Evolution (1 Sample)
The inspectors evaluated:
(1) emergency preparedness drill before evaluated NRC drill on September 17, 2025 RADIATION SAFETY 71124.05 - Radiation Monitoring Instrumentation Effluent Monitoring Calibration and Testing Program Sample (IP Section 03.03) (1 Sample)
The inspectors evaluated the calibration and maintenance of the following radioactive effluent monitoring and measurement instrumentation:
(1)
Unit 2, essential service water process monitor, 2PR03J
6 71124.06 - Radioactive Gaseous and Liquid Effluent Treatment Walkdowns and Observations (IP Section 03.01) (3 Samples)
The inspectors evaluated the following radioactive effluent systems during walkdowns:
(1) auxiliary building ventilation system, including Unit 1 auxiliary building ventilation effluent monitor (1RE-PR028) and the Unit 2 auxiliary building vent effluent monitor (2RE-PR028)
(2) liquid effluent discharge system, including the effluent release tanks, and radwaste release tank monitor (0RE-PR01J)
(3) gaseous radwaste system, including gaseous decay tanks, sampling station, and radiological waste control room Sampling and Analysis (IP Section 03.02) (3 Samples)
Inspectors evaluated the following effluent samples, sampling processes and compensatory samples:
(1) gaseous effluents released from the Unit 2 auxiliary building vents (2) liquid effluents released from the liquid effluent discharge system (3) gaseous effluents released from the gaseous decay tanks Dose Calculations (IP Section 03.03) (2 Samples)
The inspectors evaluated the following dose calculations:
(1) permit number L-20250507-465-B; Liquid Release Tank 0WX01T; May 5, 2025 (2) permit number G-20250331-2224-B; Unit 2 Containment Purge; April 14, 2025 Abnormal Discharges (IP Section 03.04) (1 Sample)
The inspectors evaluated the following abnormal discharges:
(1) 2023 gaseous abnormal release 71124.07 - Radiological Environmental Monitoring Program Environmental Monitoring Equipment and Sampling (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated environmental monitoring equipment and observed collection of environmental samples.
Radiological Environmental Monitoring Program (IP Section 03.02) (1 Sample)
(1)
The inspectors evaluated the implementation of the licensees radiological environmental monitoring program.
7 GPI Implementation (IP Section 03.03) (1 Sample)
(1)
The inspectors evaluated the licensees implementation of the Groundwater Protection Initiative (GPI) program to identify incomplete or discontinued program elements.
OTHER ACTIVITIES - BASELINE 71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
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)
MS09: Residual Heat Removal Systems (IP Section 02.08) (2 Samples)
(1)
Unit 1 (July 1, 2024, through June 30, 2025)
(2)
Unit 2 (July 1, 2024, through June 30, 2025)
MS10: Cooling Water Support Systems (IP Section 02.09) (2 Samples)
(1)
Unit 1 (July 1, 2024, through June 30, 2025)
(2)
Unit 2 (July 1, 2024, through June 30, 2025)
BI01: Reactor Coolant System (RCS) Specific Activity Sample (IP Section 02.10) (2 Samples)
(1)
Unit 1 (February 1, 2024, through August 31, 2025)
(2)
Unit 2 (February 1, 2024, through August 31, 2025)
OR01: Occupational Exposure Control Effectiveness Sample (IP Section 02.15) (1 Sample)
(1)
May 1, 2024, through August 31, 2025 PR01: Radiological Effluent Technical Specifications/Offsite Dose Calculation Manual Radiological Effluent Occurrences (RETS/ODCM) Radiological Effluent Occurrences Sample (IP Section 02.16) (1 Sample)
(1)
April 1, 2024, through August 31, 2025 71152A - Annual Follow-up Problem Identification and Resolution Annual Follow-up of Selected Issues (Section 03.03) (1 Sample)
The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:
(1)
The inspectors reviewed the implementation and tracking of the essential service water fouling monitoring program (BVP 800-30) and extent-of-condition exams.
8 71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02) (1 Sample)
(1) non-safety-related equipment installed as safety-related parts on safety-related trains INSPECTION RESULTS Licensee-Identified Non-Cited Violation 71111.15 This violation of very low safety significance was identified by the licensee and has been entered into the licensee corrective action program and is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Violation: 10 CFR 50, Appendix B, Criterion VIII, Identification and Control of Materials, Parts, and Components, requires, in part, that identification and control measures shall be designed to prevent the use of incorrect or defective material, parts, and components.
Contrary to above, the licensee failed to establish measures for the identification and control of materials, parts, and components. Specifically, the licensee failed to ensure Procurement Classification 1 (QL-1), Safety Related, components were selected for replacement in safety-related components, as required by step 4.1 of site procedure SM-AA-300-1002, Revision 11, Bill of Material Development and Right Parts Selection for Maintenance, when a non-safety-related (NSR) gauge and four NSR diaphragms were installed in safety-related systems and constitutes a performance deficiency. The NSR gauge was installed on the pressure sensing line of the 2A main steam isolation valve accumulator on April 27, 2021, discovered on August 12, 2025, and replaced on September 5, 2025. The four NSR diaphragms were installed in the 2AF005A through 2AF005D auxiliary feedwater flow control valves on April 18, 2025, discovered on August 27, 2025, and replaced on October 29, 2025.
Significance/Severity: Green. The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The inspectors determined the finding was of very low safety significance (Green) because they answered Yes to question 1 in Exhibit 2, Mitigating Systems Screening Questions.
Corrective Action References:
AR 4889796, NSR Pressure Gauge Installed in SR Application AR 4893579, NSR Diaphragm Installed in 2AF005A AR 4893583, NSR Diaphragm Installed in 2AF005B AR 4893585, NRS Diaphragm Installed in 2AF005C AR 4893586, NSR Diaphragm Installed in 2AF005D
9 Observation: Non-Safety-Related Equipment Installed as Safety-Related Parts on Safety-Related Trains 71152S The inspectors conducted a review of plant issues, with a focus on entries in the licensees corrective action program over recent months. This review identified a potential negative trend involving the installation of non-safety-related (NSR) components in safety-related (SR) applications.
- 1. NSR Pressure Gauge Installed in SR Application (AR 4889796)
A non-safety-related, Quality Level 4, pressure gauge (Part 2PI-MS251A) was installed on the safety-related 2A main steam isolation valve (MSIV) train under Work Order (WO) 4569070 on April 27, 2021. This gauge, which serves as the accumulator tank pressure indicator, remained in place for over 4 years without detection when the error was discovered on August 12, 2025. Although a past operability determination was performed, which determined there was no reason to suspect the pressure boundary would fail during a design basis event, the gauge was isolated immediately and subsequently replaced with a safety-related pressure gauge on September 5, 2025.
- 2. NSR Diaphragms Installed in SR Auxiliary Feedwater Flow Control Valves (ARs 4893585, 493583, 493585, 493586)
During the most recent Unit 2 outage, four NSR, Quality Level 4 diaphragms, were installed in place of SR, qualified diaphragms in the 2A auxiliary feedwater system flow control valves (2AF005A-D), under WOs 5411043, 5411042, 5411041, and 5411040, respectively.
The installation followed procedure MA-BY-MM-4-AF005, Revision 7, 1/2AF005A Through H Valve Repair. This issue was identified not through routine checks but as a result of a question raised by Braidwood Nuclear Plant regarding preventive maintenance frequency.
A functionality evaluation (EC 645425) was conducted, which noted that the NSR diaphragms had undergone a parts quality initiative (PQI) inspection prior to use. Although no operability concerns were identified, the licensee replaced the diaphragms with Quality Level 1 components on October 29, 2025.
In both cases, the licensee failed to meet the requirements of SM-AA-300-1002, Revision 11, Bill of Material Development and Right Parts Selection for Maintenance. Step 4.1.4 states, in part, Only Safety Related item/components (Cat ID Quality Level 1 or 2) are permissible for use, in Configuration Level 1 (Safety-Related Equipment). These oversights represent lapses in human performance which could have led to more significant consequences.
Upon discovery, the licensee did perform extent-of-condition searches and took action to replace the affected parts. The licensee also expanded the scope by including evaluation of ARs generated as a result of a potential for incorrect parts to be installed in generation of a Trend IR, AR 4901934, in order to evaluate their parts selection process performance.
The licensee identified opportunities to improve training and the parts selections. However, it is also important to stress the importance of acquiring parts that meet the design and manufacturing requirements under a quality assurance program complying with 10 CFR 50, Appendix B and their role in ensuring the continued reliability of structures, systems, and components important to the safe shutdown of the plant.
The screening and significance determinations for the installation of these NSR components are discussed in the licensee-identified non-cited violation attached to this report.
10 EXIT MEETINGS AND DEBRIEFS The inspectors verified that no proprietary information was retained or documented in this report.
On December 10, 2025, the inspectors presented the integrated inspection results to Harris Welt, Site Vice President, and other members of the licensee staff.
On September 11, 2025, the inspectors presented the radiation protection inspection results to Harris Welt, Site Vice President, and other members of the licensee staff.
On September 30, 2025, the inspectors presented the radiation protection inspection results to Jason Reed, Manager of RP Programs, and other members of the licensee staff.
11 DOCUMENTS REVIEWED Inspection Procedure Type Designation Description or Title Revision or Date Corrective Action Documents Resulting from Inspection AR 4880501 NRC ID DG M/E Lineups Need to be Revised 07/09/2025 BOP AF-E1A Auxiliary Feedwater Train A Electrical Lineup 1
BOP AF-M1A Auxiliary Feedwater System Train 'A' Valve Lineup 7
BOP DG-E1A Diesel Generator Train A Electrical Lineup 3
71111.04 Procedures BOP DG-M1A Train A Diesel Generator System Valve Lineup 14 71111.05 Miscellaneous Fire Drill Scenario
- 25-03 Barrel Storage Building 07/15/2025 HU-AA-1211-F-01 Pre-Job Briefing Checklist 10 OP-AA-101-111 Roles and Responsibilities of On-Shift Personal 15 OP-AA-101-111-1001 Operation Standards and Expectations 37 71111.11Q Procedures TQ-AA-155 Conduct of Simulator Training and Evaluation 15 AR 4868384 1A DG Loss of 80# Air Header 05/25/2025 AR 4879681 2VA04SB Welds Repairs Required 07/08/2025 AR 4879924 Delay to LCO Window Due to Additional Welds Needed 07/08/2025 AR 4880326 2B SI Lower Cooler Failed Pressure Test During Maintenance 07/10/2025 AR 4880525 Active SX Leak from 2VA04SB Lower Cooler 07/10/2025 AR 4880537 Need Contingency Weld Package for Future SI Cooler Work 07/10/2025 AR 4883026 Foreign Material Causes Loss of Control Air - 1A EDG 07/17/2025 AR 4884293 1A DG Output Breaker Opened during Monthly Surveillance 07/22/2025 AR 4884396 1A DG Inoperability Due to Control Air Loss 07/22/2025 AR 4884465 1PI-DG124 Reading Low Turbo Lube Oil Pressure 07/22/2025 AR 4885891 1A DG Non-Essential Control Air Reg Failure 07/25/2025 Corrective Action Documents AR 4888432 AR 1A DG Starting Air Systems Have Crosstalk 08/05/2025 71111.12 Drawings M-152, Sheet 15 MFRs Supplement Diagram of Diesel Generator Control Diagram Shutdown System 02/05/1998
12 Inspection Procedure Type Designation Description or Title Revision or Date M-152, Sheet 20 Control Diagram Starting System and Alarms 02/06/2013 Failure Analysis Failure Analysis of Valve, Check, Body Material Aluminum, Size 1/4 X 1 07/17/2023 Miscellaneous Maintenance Plan (Excel file) 2B Safety Injection (2SI01PB) 48hrs of 7d LCO 0
Work Orders WO 5698019 1A DG Output Breaker Opened During Monthly Surveillance 07/23/2025 Miscellaneous Major Activities for Week Week: 2536BA A-Train 09/02/2025 BFP FH-69 Hi-Trac Movement Within the Fuel Building 38 Procedures OU-AA-630-1000 Spent Fuel Loading Campaign Management 14 71111.13 Work Orders WO 5618966 2025 Dry Cask Storage Campaign 0
AR 4815961 1B DG Starting Air Receiver Pressure did not Change on Start 11/07/2025 AR 4843282 1B DG Starting Air Receiver Pressure Uneven Change on Start 03/07/2025 AR 4863962 1B DG Starting Air Receiver Pressure Uneven Change on Start 05/07/2021 AR 4872849 1B DG Starting Receiver Degraded Trend 06/11/2025 AR 4873850 1B DG Starting Air Receiver Pressure Uneven SAT Outage 03/09/2025 AR 4884293 1A DG Output Breaker Opened during Monthly Surveillance 07/22/2025 AR 4884396 1A DG Inoperability Due to Control Air Loss 07/22/2025 AR 4884465 1PI-DG124 Reading Low Turbo Lube Oil Pressure 07/22/2025 AR 4889796 NSR Pressure Gauge Installed in SR Application 08/12/2025 AR 4893579 NSR Diaphragm Installed in 2AF005A 08/27/2025 AR 4893583 NSR Diaphragm Installed in 2AF005B 08/27/2025 AR 4893585 NSR Diaphragm Installed in 2AF005C 02/27/2025 Corrective Action Documents AR 4893586 NSR Diaphragm Installed in 2AF005D 08/27/2025 M-152, Sheet Number 15 MFRs Supplement Diagram of Diesel Generator Control Diagram Shutdown System 02/05/1998 Drawings M-152, Sheet Number 20 Control Diagram Starting Systems and Alarms 02/06/2013 71111.15 Engineering Changes EC 345722 Replace MSIV N2 Pressure Gauge with Safety Related Gauges 04/05/2005
13 Inspection Procedure Type Designation Description or Title Revision or Date EC 645425 2AF005A-D Functionality Evaluation for NSR Actuator Diaphragm 09/04/2025 CES SO-0351 MO-7176 Report of Witness Tests of KSV-20-T Engine-Generator Set 11/30/1979 CES-0420-100 Report of Witness Tests KSV-20T Engine-Generator Set 09/20/1984 Logs Byron Logs 22-23 July 07/22/2025 Miscellaneous Past Operability 2A MSIV Past Operability 09/17/2025 WO 4569070 EWP IM Perform Calibration of 2PI-MS251A 04/27/2021 WO 5411040 Rebuild Actuator/Replace Elastomers 2AF005D 04/18/2025 WO 5411041 Rebuild Actuator/Replace Elastomers 2AF005B 04/18/2025 WO 5411042 Rebuild Actuator/Replace Elastomers 2AF005C 04/18/2025 Work Orders WO 5411043 Rebuild Actuator/Replace Elastomers 2AF005A 04/18/2025 AR 4246114 EC 398675 (EDG Frequency and Voltage Variation) 08/09/2019 AR 4866048 Post-B2R25 Incore Blocked Thimbles 05/07/2025 AR 4872400 2B AF PP is Leaking a Decent Amount of Exhaust to the Room 06/12/2025 AR 4880326 2B SI Lower Cooler Failed Pressure Test During Maintenance 07/10/2025 AR 4880754 Minor Active Leak on Lower Cooler of 2VA04SB 07/11/2025 Corrective Action Documents AR 4886534 Incore Blocked Thimble #15 07/23/2025 0BOSR 7.9.6-1 Essential Service Water Makeup Pump 0A Monthly Operability Surveillance 44 1BOSR 5.5.8.CS.5-2c Unit One Comprehensive Inservice Testing (IST)
Requirements for Containment Spray Pump 1CS01PB 11 2BOSR 5.5.8.SI.5-2A Unit Two Group A Inservice Testing (IST) Requirements for Safety Injection Pump 2SI01PB 5
2BOSR 7.5.4-2 Unit Two Auxiliary Feedwater Pump Monthly Surveillance 40 Procedures BOP IC-3 Moveable Incore Detectors Flux Mapping Procedure 27 WO 5535776 Essential Service Water Makeup Pump Support 0BVSR Z.7.A.6-1 09/23/2025 WO 5647834 OPS Perform 1BOSR 5.5.8.CS.5-2C 1B CS Pump Comprehensive 07/17/2025 71111.24 Work Orders WO 5677654 (NEIL)-2SI01PB Group A IST Requirements for Safety 07/11/2025
14 Inspection Procedure Type Designation Description or Title Revision or Date Injection Pump WO 5678488 DC 211 Battery Voltage Low (Cell 44) 09/12/2025 WO 5681243 1B DG Staring Air Receiver Pressure Uneven Change on Start 09/12/2025 WO 5696620 (NEIL) - 2B Diesel Driven AF Pump Monthly Surveillance 08/05/2025 Byron 2025 Integrated Drill Byron 2025 Integrated Drill Binder #3 07/24/2025 71114.06 Miscellaneous Byron 2025 Pre-Exercise Byron 2025 Pre-exercise Binder #31 09/17/2025 71124.05 Miscellaneous 2PR03J Calibration Source Tracking 09/30/2025 2022 Annual Radioactive Effluent Release Report 04/27/2023 2024 Annual Radioactive Effluent Release Report 04/28/2025 Software Quality Assurance for OpenEMS Byron Nuclear Power Plant 2023 Annual Radioactive Effluent Release Report 04/25/2024 2021 Annual Radioactive Effluent Release Report 04/02/2022 L-20250507-465-B Liquid Permit Release Information 05/07/2025 2C.111 Gaseous Pre-Release Permit Report, Gaseous Release Permit Report, RP-BY-90-0-0H3 Bubbler, Supporting Documentation and BCP 400-TCNMT/Continuous 03/31/2025 CY-BY-110-600-1 Chemistry Sample Points - Turbine Building 23 G-20250822-2429-B Gas Permit Release Information 08/22/2025 L-20250505-463-B Liquid Permit Release Information 05/05/2025 Miscellaneous L-20250822-488-B Liquid Permit Release Information 08/22/2025 CY-AA-170-000 Radioactive Effluent and Monitoring Programs 6
CY-AA-170-210 Potentially Contaminated Systems Controls Program 2
CY-AA-170-2300 Determination of Carbon-14 in Gaseous Effluents 0
CY-BY-170-301 Offsite Dose Calculation Manual for Byron Station Units 1 and 2 18 71124.06 Procedures Y-AA-170-1100 Quality Assurance for Radiological Monitoring Programs 4
15 Inspection Procedure Type Designation Description or Title Revision or Date Self-Assessments 04893178 2025 RETS/REMP 71124.06 & 71124.07 09/05/2025 Calibration Records CY-BY-130-8000 CY-BY-130-8001 Attachment 3 Compositor Performance Check Sheet, CY-BY-130-8000 Attachment 2 NPDES/Compositor Performance Check Sheet 06/4/2025 -
6/07/2025 06/11/2025 AR 4668429 NOS ID: Correct ODCM for Two Offsite Dosimeters 04/07/2023 AR 4705740 No Flow into CWBD Steel Pot for ODCM Sampling 09/29/2023 AR 4882979 Third Party Lab Issues with RETS/REMP Reports 07/17/2025 Corrective Action Documents AR 4886899 CGS Vendor Labs Unable to Meet Ni-63 Specs. on Byron Fish 07/29/2025 BYRON 2023-0022 2022 Annual Radiological Environmental Operating Report (AREOR) 05/04/2023 BYRON 2024-0028 2023 Annual Radiological Environmental Operating Report (AREOR) 05/09/2024 Miscellaneous BYRON 2025-0029 2024 Annual Radiological Environmental Operating Report (AREOR) 05/12/2025 0BCSR 12.A.1-7 Radiological Environmental Monitoring, Milk Ingestion -
Monthly 8
0BCSR 12.B.1-1 Radiological Environmental Monitoring, Land Use Census -
Annual 3
CY-AA-170-100 Radiological Environmental Monitoring Program 2
CY-BY-170-301 Offsite Dose Calculation Manual for Byron Station Units 1 and 2 18 CY-BY-408-416-01 Radiological Groundwater Protection Program Sampling 1
EN-AA-407 Response to Inadvertent Releases of Licensed Materials to Groundwater, Surface Water, Soil or Engineered Structures 12 EN-AA-408 Radiological Groundwater Protection Program 3
EN-AA-408-4000 Radiological Groundwater Protection Program Implementation 14 71124.07 Procedures EN-BY-408-4160 RGPP Reference Material for Byron Generating Station 18 71151 Miscellaneous NRC Performance Indicator Data; Mitigating Systems -
Mitigating System Performance Index for Cooling Water Systems 07/01/2024-06/30/2025
16 Inspection Procedure Type Designation Description or Title Revision or Date NRC Performance Indicator Data; Mitigating Systems -
Mitigating System Performance Index for Residual Heat Removal Systems 07/01/2024-06/30/2025 NRC Performance Indicator Data; Mitigating Systems -
Mitigating System Performance Index for Heat Removal Systems 07/01/2024-06/30/2025 LS-AA-2140 Monthly Data Elements for NRC ROP Indicator -
Occupational Exposure Control Effectiveness various LS-AA-2150 Monthly Data Elements for NRC ROP Indicator -
RETS/ODCM Radiological Effluent Occurrences various Corrective Action Documents AR 4495844 0SX98AB - B2R23 UT Inspection Results 04/27/2022 Corrective Action Documents Resulting from Inspection AR 4820258 NRC ID: NRC Document Request Not Provided in a Timely Manner 07/15/2025 Engineering Evaluations EC 634325 B2R23 Minimum Wall Thickness Evaluation for Raw Water Program 2
BVP 800-30 Essential Service Water Fouling Monitoring Program (GL 89-13 Program Basis Document) 18 71152A Procedures ER-AA-5400-1001 Raw Water Piping Integrity Management Guide 12 AR 4889796 NSR Pressure Gauge Installed in SR Application 08/12/2025 AR 4893579 NSR Diaphragm Installed in 2AF005A 08/27/2025 AR 4893583 NSR Diaphragm Installed in 2AF005B 08/27/2025 AR 4893585 NSR Diaphragm Installed in 2AF005C 08/27/2025 AR 4893586 NSR Diaphragm Installed in 2AF005D 08/27/2025 Corrective Action Documents AR 4901934 Trend IR: Cases Where the Wrong Parts Were Installed 09/30/2025 71152S Engineering Changes EC 645425 2AF005A-D Functionality Evaluation for NSR Actuator Diaphragm 09/05/2025