IR 05000353/2024004

Integrated Inspection Report 05000353/2024004 and 05000353/2024004

ML25043A152
Person / Time
Site:	Limerick
Issue date:	02/12/2025
From:	Sarah Elkhiamy Division of Operating Reactors
To:	Rhoades D Constellation Energy Generation, Constellation Nuclear
References
IR 2024004
Download: ML25043A152 (1)

Text

February 12, 2025

SUBJECT:

LIMERICK GENERATING STATION, UNITS 1 AND 2 - INTEGRATED INSPECTION REPORT 05000352/2024004 AND 05000353/2024004

Dear David Rhoades:

On December 31, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Limerick Generating Station, Units 1 and 2. On January 28, 2025, the NRC inspectors discussed the results of this inspection with Michael Gillin, Site Vice President, and other members of your staff. The results of this inspection are documented in the enclosed report.

One finding of very low safety significance (Green) is documented in this report. This finding involved a violation of NRC requirements. We are treating this violation as a non-cited violation (NCV) consistent with Section 2.3.2 of the Enforcement Policy.

A licensee-identified violation which was determined to be Severity Level IV is documented in this report. We are treating this violation as an NCV consistent with Section 2.3.2 of the Enforcement Policy.

If you contest the violations or the significance or severity of the violations 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 I; the Director, Office of Enforcement; and the NRC Resident Inspector at Limerick Generating Station, Units 1 and 2.

If you disagree with a cross-cutting aspect assignment in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your disagreement, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region I; and the NRC Resident Inspector at Limerick Generating Station, Units 1 and 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, Sarah H. Elkhiamy, Chief Projects Branch 4 Division of Operating Reactor Safety

Docket Nos. 05000352 and 05000353 License Nos. NPF-39 and NPF-85

Enclosure:

As stated

Inspection Report

Docket Numbers:

05000352 and 05000353

License Numbers:

NPF-39 and NPF-85

Report Numbers:

05000352/2024004 and 05000353/2024004

Licensee:

Constellation Energy Generation, LLC

Facility:

Limerick Generating Station, Units 1 and 2

Location:

Sanatoga, PA 19464

Inspection Dates:

October 1, 2024 to December 31, 2024

Inspectors:

A. Ziedonis, Senior Resident Inspector

L. Grimes, Resident Inspector

B. Edwards, Health Physicist

S. Mercurio, Emergency Preparedness Inspector

Approved By:

Sarah H. Elkhiamy, Chief

Projects Branch 4

Division of Operating Reactor Safety

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Limerick Generating Station, Units 1 and 2, 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: 7115

List of Findings and Violations

Failure to Ensure the Alert and Notification System (ANS) Siren Program Complied with the Approved Federal Emergency Management Agency (FEMA) ANS Design Report Cornerstone Significance Cross-Cutting Aspect Report Section Emergency Preparedness Green NCV 05000352,05000353/2024004-01 Open/Closed

[H.1] -

Resources 71114.02 The inspectors identified a Green non-cited violation of Title 10 of the Code of Federal Regulations (10 CFR) 50.54(q)(2) and 10 CFR 50.47(b)(5). Specifically, the licensee failed to ensure the ANS siren program complied with the approved FEMA ANS Design Report by ensuring that foliage growth did not adversely impact siren operation or limit access to the siren.

Additional Tracking Items

Type Issue Number Title Report Section Status LER 05000352/2024-003-00 LER 2024-003-00 for Limerick Generating Station,

Unit 1, Core Operating Limits Report Thermal Limit Exceeded for Unit 1 Fuel Bundle GGK123 71153 Closed

PLANT STATUS

Unit 1 began the inspection period at rated thermal power (RTP). On November 23, 2024, operators lowered thermal power to approximately 65 percent for a control rod pattern adjustment, electrohydraulic fluid system leak repairs, and turbine valve testing. The unit was returned to RTP on November 24, 2024, and remained at or near RTP for the remainder of the inspection period.

Unit 2 began the inspection period at RTP. On November 16, 2024, operators lowered thermal power to approximately 65 percent for a control rod pattern adjustment and leak repairs on the feedwater heating system. The unit was restored to RTP on November 18, 2024, and remained at or near RTP for the remainder of the inspection period.

INSPECTION SCOPES

Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors performed activities described in IMC 2515, Appendix D, Plant Status, observed risk significant activities, and completed 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.

71111.01 - Adverse Weather Protection

Seasonal Extreme Weather Sample (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated readiness for seasonal extreme weather conditions prior to the onset of winter cold temperatures for the following systems:

• Unit 1 and Unit 2 emergency diesel generators (EDGs)

• Unit 1 and Unit 2 reactor core isolation cooling (RCIC) systems

• Unit 1 and Unit 2 high pressure coolant injection (HPCI) systems

• Unit 1 and Unit 2 residual heat removal (RHR) systems

71111.04 - Equipment Alignment

Partial Walkdown Sample (IP Section 03.01) (4 Samples)

The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:

(1) Unit 2 RCIC system following degraded main control room hand-switch condition for normal supply from the condensate storage tank on October 16, 2024

(2) Unit 2 core spray system on October 31, 2024

(3) Unit 1 HPCI system following pump, valve, and flow testing on November 8, 2024

(4) Unit common residual heat removal service water (RHRSW) 'B' train during the weeks of November 12 and December 16, 2024

71111.05 - Fire Protection

Fire Area Walkdown and Inspection Sample (IP Section 03.01) (4 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) Unit 2 fire area 61, 'A' core spray pump room on October 9, 2024

(2) Unit common fire area 26, remote shutdown room on October 15, 2024

(3) Unit 2 fire area 64, reactor enclosure cooling water heat exchanger area on October 24, 2024

(4) Unit 1 fire area 47, standby liquid control and general equipment areas, and fuel pool cooling water area on December 6, 2024

71111.06 - Flood Protection Measures

Flooding Sample (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated internal flooding mitigation protections in the unit common control enclosure 4 kilovolt switchgear rooms and corridor areas on December 27, 2024.

71111.11A - Licensed Operator Requalification Program and Licensed Operator Performance

Requalification Examination Results (IP Section 03.03) (1 Sample)

(1) The inspectors reviewed and evaluated the licensed operator examination failure rates for the requalification annual operating exam completed on November 21, 2024.

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 main control room during portions of a Unit 2 load drop for a rod pattern adjustment and feedwater heating system steam leak repairs on November 16 and 18, 2024.

Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)

(1) The inspectors observed and evaluated licensed operator classroom training associated with the digital modification project on December 2, 2024.

71111.12 - Maintenance Effectiveness

Maintenance Effectiveness (IP Section 03.01) (1 Sample)

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 and Unit 2 general EDG maintenance effectiveness to address lubricating oil entrainment in the intercooler air subsystem during the weeks of November 18 and December 9, 2024

Aging Management (IP Section 03.03) (1 Sample)

The inspectors evaluated the effectiveness of the aging management program for the following SSCs that did not meet their inspection or test acceptance criteria:

(1) Unit 1 spent fuel pool boral coupon thickness exceeded acceptance criteria in RT-3-097-572-1, "Maximum Density Spent Fuel Storage Rack Test Coupon Analysis,"

(IR 4711193) during the week of December 9, 2024

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) Unit 2 reactor enclosure 'A' supply fan failure following catastrophic failure and thrown fan blades inside the supply fan housing during the week of September 30, 2024

(2) Unit 1 control rod position indication system failure during the week of October 28, 2024

(3) Unit 2 elevated risk during planned HPCI testing on November 7, 2024

(4) Unit 2 emergent work to perform '6A' feedwater heater relief valve discharge piping steam leak repairs during the weeks of November 11 and 18, 2024

(5) Unit 1 'B' RHRSW pipe repairs following leakage during testing on December 16, 2024

71111.15 - Operability Determinations and Functionality Assessments

Operability Determination or Functionality Assessment (IP Section 03.01) (5 Samples)

The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:

(1) Unit 1 D12 EDG elevated lube oil consumption rate during 24-hour endurance run on October 7 and 8, 2024

(2) Unit 2 D23 EDG elevated fuel oil consumption rate during 24-hour endurance run during the week of October 21, 2024

(3) Unit common RHRSW piping with pinhole leak and housekeeping clamp during the week of November 11 and 18, 2024

(4) Unit 1 turbine control valve fast closure reactor protection system instrumentation following unsatisfactory surveillance test acceptance criteria during the weeks of November 25 and December 2, 2024

(5) Unit 2 feedwater level control system with the 'C' reactor feedwater pump discharge motor operated valve electrical supply power breaker de-energized open during the weeks of December 2 and 9, 2024

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) Unit 2 'B' main steam line high temperature automatic isolation removal during the week of October 21, 2024

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) (7 Samples)

(1) Unit common RHRSW 'B' loop pump, valve, and flow test following lift adjustment for pump total dynamic head in the alert range on October 11, 2024

(2) Unit 1 'D' RHR following planned maintenance on October 15, 2024

(3) Unit 2 RCIC suction valves following remote control hand-switch replacement during the week of October 28, 2024

(4) Unit common 'C' emergency service water pump following motor replacement during the week of November 10, 2024

(5) Unit 2 'A' RHR drywell spray outboard isolation valve diagnostic testing and stroke time testing following planned maintenance on December 12, 2024

(6) Unit 1 'B' core spray pump, valve, and flow testing following planned maintenance on December 20, 2023

(7) Unit common 'A' emergency service water header return valves from Unit 2 RCIC room coolers following replacement during the week of December 23, 2024

Surveillance Testing (IP Section 03.01) (5 Samples)

(1) Unit 2 D12 EDG 24-hour endurance surveillance test during the week of October 7, 2024

(2) Unit 2 D23 4 kilovolt emergency safeguard bus undervoltage surveillance test on October 21, 2024

(3) Unit 2 D23 EDG 24-hour endurance surveillance test during the week of October 21, 2024

(4) Unit 1 main turbine control valve exercise and reactor protection system channel functional surveillance test, OPCON 1, 2 on November 25, 2024

(5) Unit 1 RCIC pump, valve, and flow surveillance test on December 13, 2024

Inservice Testing (IST) (IP Section 03.01) (1 Sample)

(1) Unit 1 HPCI pump, valve, and flow inservice test on November 7, 2024

71114.02 - Alert and Notification System Testing

Inspection Review (IP Section 02.01-02.04) (1 Sample)

(1) The inspectors evaluated the licensee's maintenance and testing of the station ANS on November 4 through November 7, 2024, for the period of September 2022 through October 2024.

71114.03 - Emergency Response Organization Staffing and Augmentation System

Inspection Review (IP Section 02.01-02.02) (1 Sample)

(1) The inspectors evaluated the readiness of the Emergency Preparedness Organization on November 4 through November 7, 2024, for the period of September 2022 through October 2024.

71114.04 - Emergency Action Level and Emergency Plan Changes

Inspection Review (IP Section 02.01-02.03) (1 Sample)

(1) The inspectors evaluated the following submitted Emergency Action Level and Emergency Plan changes:

• Evaluation 22-68, EP-AA-120-F-06, Evacuation Time Estimate Review Checklist, Revision C

• Evaluation 23-06, EP-AA-121, Emergency Response Facilities and Equipment Readiness, Revision 20

• Evaluation 23-48, EP-AA-120-1006, EP Reportability - Loss of Emergency preparedness Capabilities, Revision 8

• Evaluation 24-21, EP-AA-120 & EP-AA-120-F-01, Revisions 23 and Q

This evaluation does not constitute NRC approval.

71114.05 - Maintenance of Emergency Preparedness

Inspection Review (IP Section 02.01 - 02.11) (1 Sample)

(1) The inspectors evaluated the maintenance of the emergency preparedness program on November 4 through November 7, 2024, for the period of September 2022 through October 2024.

71114.06 - Drill Evaluation

Required Emergency Preparedness Drill (1 Sample)

(1) The inspectors observed and evaluated the adequacy of an emergency preparedness drill on October 9,

71124.06 - Radioactive Gaseous and Liquid Effluent Treatment

Walkdowns and Observations (IP Section 03.01) (4 Samples)

The inspectors evaluated the following radioactive effluent systems during walkdowns:

(1) Radioactive Waste Liquid Radiation monitor 0O5368

(2) Unit 1 Service Water Radiation Monitor # 1OS164

(3) RHR (B-train) Service Water Radiation Monitor

(4) Hold pond continuous release point

Sampling and Analysis (IP Section 03.02) (4 Samples)

Inspectors evaluated the following effluent samples, sampling processes, and compensatory samples:

(1) North Stack iodine cartridge collection and analysis

(2) Unit 1 south stack particulate filter collection and analysis

(3) Unit 2 south stack iodine cartridge collection and analysis

(4) Wide Range Accident Monitor (WRAM) silver zeolite cartridge collection and analysis

Dose Calculations (IP Section 03.03) (3 Samples)

The inspectors evaluated the following dose calculations:

(1) Dose calculations for batch release permit L-20240724-386-B

(2) Dose calculations for batch release permit L-20230505-244-B

(3) Dose calculations for batch release permit L-20240419-360-B

Abnormal Discharges (IP Section 03.04) (1 Sample)

The inspectors evaluated the following abnormal discharges:

(1) 5 drums of drywell chill water batch release to hold pond (permit #L-20220706-184-B)

71124.08 - Radioactive Solid Waste Processing & Radioactive Material Handling, Storage, &

Transportation

Radioactive Material Storage (IP Section 03.01)

The inspectors evaluated the licensees performance in controlling, labeling, and securing the following radioactive materials:

(1) Storage of High Integrity Containers (HICs) storage in the HLSA building (2)2002 Pad Hold Pond sludge drying location

Radioactive Waste System Walkdown (IP Section 03.02) (2 Samples)

The inspectors walked down the following accessible portions of the solid radioactive waste systems and evaluated system configuration and functionality:

(1) Condensate Phase Separator Tank Room #125

(2) Equipment Drain Surge Tank Pump Room #248

Waste Characterization and Classification (IP Section 03.03) (2 Samples)

The inspectors evaluated the following characterization and classification of radioactive waste:

(1) Waste stream deep bed resin L100268-4.

(2) Waste stream waste sludge 24DR3018 1ASRT

Shipping Records (IP Section 03.05) (4 Samples)

The inspectors evaluated the following non-excepted radioactive material shipments through a record review:

(1) Low Specific Activity - II(LSA-II) resin liner in HIC shipment #MW-24-043

(2) Low Specific Activity - II (LSA-II) resin liner in HIC shipment #MW-22-033

(3) Radioactive Material Type B Reactor Water Cleanup resin liner in HIC shipment

1. MW-23-003

(4) Low Specific Activity - II(LSA-II) resin liner in HIC shipment #MW-23-040

OTHER ACTIVITIES - BASELINE

===71151 - Performance Indicator Verification

The inspectors verified licensee performance indicators submittals listed below:

MS10: Cooling Water Support Systems (IP Section 02.09)===

(1) Unit 1 for the period of October 1, 2023 through September 30, 2024

(2) Unit 2 for the period of October 1, 2023 through September 30, 2024

BI01: Reactor Coolant System (RCS) Specific Activity Sample (IP Section 02.10) (2 Samples)

(1) Unit 1 for the period of October 1, 2023 through September 30, 2024

(2) Unit 2 for the period of October 1, 2023 through September 30, 2024

BI02: RCS Leak Rate Sample (IP Section 02.11) (2 Samples)

(1) Unit 1 for the period of October 1, 2023 through September 30, 2024

(2) Unit 2 for the period of October 1, 2023 through September 30, 2024

OR01: Occupational Exposure Control Effectiveness Sample (IP Section 02.15) (1 Sample)

(1) October 1, 2023 through September 30, 2024 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) October 1, 2023 through September 30, 2024

EP01: Drill/Exercise Performance (DEP) Sample (IP Section 02.12) (1 Sample)

(1) July 1, 2023 through September 30, 2024

EP02: Emergency Response Organization (ERO) Drill Participation (IP Section 02.13) (1 Sample)

(1) July 1, 2023 through September 30, 2024

EP03: Alert And Notification System (ANS) Reliability Sample (IP Section 02.14) (1 Sample)

(1) July 1, 2023 through September 30, 2024

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) The inspectors reviewed Constellation's corrective action program evaluation (CAPE)

===4731070-07 and work group evaluation (WGE) 4805275-10 in response to multiple reactor and turbine building supply fan catastrophic failures

(2) The inspectors reviewed Constellation's CAPE 4727659-08 in response to Unit 1 'D' safety relief valve leakage and associated forced outage 1F60

(3) The inspectors reviewed Constellation's WGE 4765933-18 in response to the identification of a mis-oriented water rod in fuel bundle GGK123

71152S - Semiannual Trend Problem Identification and Resolution

Semiannual Trend Review (Section 03.02)===

(1) The inspectors reviewed the licensees corrective action plan for potential adverse trends that might be indicative of a more significant safety issue

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 05000352/2024-003-00, Core Operating Limits Report (COLR) Thermal Limit Exceeded for Fuel Bundle GGK123 (ADAMS Accession No. ML24170A772). The inspectors determined that the cause of the condition described in the LER was not reasonably within the licensee's ability to foresee and correct, and therefore was not reasonably preventable. No performance deficiency was identified. The enforcement aspects of this LER are discussed in the Results section of this report. This LER is closed.

INSPECTION RESULTS

Failure to Ensure the Alert and Notification System (ANS) Siren Program Complied with the Approved Federal Emergency Management Agency (FEMA) ANS Design Report Cornerstone Significance Cross-Cutting Aspect Report Section Emergency Preparedness

Green NCV 05000352,05000353/2024004-01 Open/Closed

[H.1] -

Resources 71114.02 The inspectors identified a Green non-cited violation of Title 10 of the Code of Federal Regulations (10 CFR) 50.54(q)(2) and 10 CFR 50.47(b)(5). Specifically, the licensee failed to ensure the ANS siren program complied with the approved FEMA ANS Design Report by ensuring that foliage growth did not adversely impact siren operation or limit access to the siren.

Description:

The Limerick Generating Station (LGS) site is located in Limerick Township, Montgomery County, Pennsylvania, about 30 miles northwest of Philadelphia along the Schuylkill River. The Limerick 10-mile emergency planning zone (EPZ) area is 360.5 square miles and includes portions of Montgomery, Chester, and Berks County. The terrain is predominantly rolling hills.

There are seven boroughs within the EPZ that have population density greater than 2,000 people per square mile. The total area of these boroughs is 13.8 square miles. Thus, minimum siren system sound coverage outside these boroughs has to be at least 60 decibels relative to the carrier (dBC) and inside these areas has to be at least 70 dBC. The ANS consists of 165 American Signal Corporation Tempest Model T-128 sirens mounted on 60-foot galvanized steel poles located throughout the 10-mile EPZ.

The NRC inspectors selected a sample of the 165 sirens in the EPZ to inspect for overall material condition during the emergency preparedness program inspection on November 4, 2024, using maintenance records from 2023. The inspectors identified a number of the sirens appeared to have foliage and growth within the specified distance of 25 feet from the siren head based upon photographs. The completed maintenance records for 2024 were not available for review.

The design report states that the maintenance program also includes monitoring tree growth at each siren site to assure that nearby foliage is below the top of the mounting pole, so it does not interfere with near-field siren sound propagation (e.g., tree growth is at least 25 feet away or below the siren horn), and does not cause excessive radio frequency scatter (i.e.,

pine needles), as well as not provide ready access to siren control boxes by squirrels or other vermin. Constellation failed to incorporate this standard into their work order packages.

Corrective Actions: Constellation staff entered additional information into the corrective action program to capture the extent of condition review to ensure formal documentation of the condition of the sirens with respect to foliage growth. The contracted siren vendor performing maintenance in still in progress so that the sirens meet the requirements specified in the FEMA approved ANS Design Report.

Corrective Action References: Issue Reports 04792666, 04794971, and 04814336

Performance Assessment:

Performance Deficiency: The inspectors determined that the siren maintenance was not in compliance with the requirements in the FEMA ANS Design Report, which is a performance deficiency that was reasonably within the ability of the licensee to foresee and correct.

Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Facilities and Equipment attribute of the Emergency Preparedness cornerstone and adversely affected the cornerstone objective to ensure that the licensee is capable of implementing adequate measures to protect the health and safety of the public in the event of a radiological emergency. Specifically, the licensee failed to ensure that tree growth did not adversely affect siren operation or limit access as specified in the approved design report.

Significance: The inspectors assessed the significance of the finding using IMC 0609, Appendix B, Emergency Preparedness SDP. The performance deficiency was determined to have very low safety significance (Green) because licensee ANS test and maintenance programs do not comply with requirements in the ANS design report.

Cross-Cutting Aspect: H.1 - Resources: Leaders ensure that personnel, equipment, procedures, and other resources are available and adequate to support nuclear safety.

Specifically, Constellation failed to ensure adequate oversight of the maintenance the vendor performed to ensure it was conforming with the FEMA-approved design report.

Enforcement:

Violation: 10 CFR 50.54(q)(2) requires that a holder of a nuclear power reactor operating license under this part, shall follow and maintain the effectiveness of an emergency plan that meets the requirements in Appendix E to this part and the planning standards of 10 CFR 50.47(b).

10 CFR 50.47(b)(5) requires, in part, the means to provide early notification and clear instruction to the populace within the plume exposure pathway EPZ have been established.

Section IV.D.3 of Appendix E to 10 CFR Part 50 requires, in part, the licensee demonstrate the appropriate governmental authorities have the capability to make a public alerting and notification decision promptly, each nuclear power reactor licensee shall demonstrate that administrative and physical means have been established for alerting and providing prompt instructions to the public within the plume exposure pathway EPZ, and that the design objective of the prompt public ANS shall be to have the capability to essentially complete the initial alerting and initiate notification of the public within the plume exposure pathway EPZ within approximately 15 minutes. To accomplish this, the licensee implements the program in the Limerick Generating Station (LGS) Public Alert and Notification System (ANS) Design Report, dated February 2017, Revision 3, which describes siren design, testing, and maintenance activities. The design report states that the maintenance program also includes monitoring tree growth at each siren site to assure that nearby foliage is below the top of the mounting pole, so it does not interfere with near-field siren sound propagation (e.g., tree growth is at least 25 feet away or below the siren horn), and does not cause excessive radio frequency scatter (i.e., pine needles), as well as not provide ready access to siren control boxes by squirrels or other vermin.

Contrary to the above, prior to November 6, 2024, the licensee did not maintain effectiveness of their emergency plan in that the licensee failed to adequately monitor tree growth at each siren site, in accordance with the FEMA-approved design report, to ensure that nearby foliage was below the top of the mounting pole, so that it did not interfere with near-field siren sound propagation, and did not cause excessive radio frequency scatter, as well as not provide ready access to siren control boxes by squirrels or other vermin.

Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.

Observation: Semiannual Trend Review: Adverse Trend of Building Enclosure Supply Fan Catastrophic Failures 71152S The inspectors performed a semiannual review to identify trends that might indicate the existence of a more significant safety issue, including issues that may have been documented outside the normal corrective action program. Overall, the inspectors determined that Constellation was appropriately identifying, evaluating, and resolving adverse trends. In particular, the inspectors observed one self-revealing adverse trend involving catastrophic failures of the reactor and turbine enclosure supply fans, where each fan failed in a manner that threw multiple fan blades within its respective supply fan plenum enclosure. Specifically, between September 28, 2023, and September 29, 2024, the station experienced a failure of the Unit 1 'B' turbine enclosure supply fan (IR 4705596), a failure of the Unit 2 'C' reactor enclosure supply fan (IR 4755684), a failure of the Unit 2 'B' reactor enclosure supply fan (IR 4731070), and a failure of the Unit 2 'A' reactor enclosure supply fan (IR 4805275).

In response, Constellation performed CAPE 4731070-07 to evaluate the casual aspects associated with the equipment failures, performed WGE 4805275-10 to evaluate the organizational and programmatic aspects that led to the repetitive equipment failures, instituted an adverse condition monitoring plan for the turbine and reactor enclosure ventilation systems on both units, and established a high impact team of cross-departmental staff from operations, maintenance, and engineering to focus on restoring overall system health. The inspectors reviewed the IRs and evaluations, performed walkdowns in the plant, and discussed system performance with various Constellation staff from operations, maintenance, and engineering. The inspectors determined that Constellation was taking reasonable actions to correct the adverse trend. The inspectors did not identify any findings or violations of more than minor significance.

Licensee-Identified Non-Cited Violation 71153 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: Limerick Unit 1 Technical Specification (TS) Limiting Condition for Operation (LCO)3.2.3, "Minimum Critical Power Ratio (MCPR), requires all MCPR values to be greater than or equal to the MCPR operating limits specified in the COLR when thermal power is greater than or equal to 25 percent. With the MCPR value less than the value specified in the COLR, TS LCO 3.2.3, Action b, requires corrective actions to be initiated within 15 minutes, and the MCPR value restored to within the required limits within two-hours, or reduce thermal power to less than 25 percent within the next 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

Contrary to the above, with a mis-oriented water rod and four grid spacers out of their expected location, fuel bundle GGK123 was determined to have not met the limits specified in the COLR, for greater than the time periods allowable under TS LCO 3.2.3, Action b, with thermal power greater than 25 percent.

Significance/Severity: No performance deficiencies were identified against Constellation.

NRC Enforcement Policy, Section 2.2.1, states, in part, that, whenever possible, the NRC uses risk information in assessing the safety significance of violations. In accordance with IMC 0609, Appendix A, inspectors determined the issue was of very low safety significance because all of the screening questions under Exhibit 3, Barrier Integrity, were answered no.

Accordingly, after considering that the violation represented very low safety significance, with no associated performance deficiency, the inspectors concluded the violation was of Severity Level IV under the traditional enforcement process.

In response to the issues described in Part 21 safety communication 22-04 (ML22334A267),the NRC Quality Assurance and Vendor Inspection Branch conducted inspection at Global Nuclear Fuel - America, LLC, and identified nonconformances that were documented in Inspection Report 99901376/2023-201 (ML23125A314).

Corrective Action References: IR 4765933, WGE 4765933-18, and LER 2024-003 (ML24170A772)

EXIT MEETINGS AND DEBRIEFS

The inspectors verified no proprietary information was retained or documented in this report.

• On January 28, 2025, the inspectors presented the integrated inspection results to Michael Gillin, Site Vice President, and other members of the licensee staff.

• On November 7, 2024, the inspectors presented the Exit Debrief for IP 71124.08 Radioactive Waste Processing Systems inspection results to Mike Gillin, Site Vice President, and other members of the licensee staff.

• On November 7, 2024, the inspectors presented the emergency preparedness program inspection results to Michael Gillin, Site Vice President, and other members of the licensee staff.

• On September 19, 2024, the inspectors presented the exit debrief for RP Inspection 71124.06 RETS inspection results to Mike Gillin, Site Vice President, and other members of the licensee staff.

DOCUMENTS REVIEWED

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

71111.24

Corrective Action

Documents

IR 4710075

Work Orders

5408879

71114.02

Corrective Action

Documents

04792666

04794971

04814336

Miscellaneous

Limerick Generating Station (LGS) Public Alert and

Notification System (ANS) Design Report

Revision 3

71114.04

Procedures

EP-AA-120-1001

CFR 50.54(q) Change Evaluation

Revision 11

71114.05

Corrective Action

Documents

Resulting from

Inspection

04818928

Miscellaneous

EP-AA-1000

Exelon Nuclear Standardized Radiological Emergency Plan

Revision 33

EP-AA-1008

Exelon Nuclear Radiological Emergency Plan Annex for

Limerick Generating Station

Revision 32