IR 05000334/2025001

Integrated Inspection Report 05000334/2025001 and 05000412/2025001

ML25133A023
Person / Time
Site:	Beaver Valley
Issue date:	05/13/2025
From:	Young R Division of Operating Reactors
To:	Blair B Vistra Operations Company
References
IR 2025001
Download: ML25133A023 (1)

Text

May 13, 2025

SUBJECT:

BEAVER VALLEY POWER STATION, UNITS 1 AND 2 - INTEGRATED INSPECTION REPORT 05000334/2025001 AND 05000412/2025001

Dear Barry Blair:

On March 31, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Beaver Valley Power Station, Units 1 and 2. On April 22, 2025, the NRC inspectors discussed the results of this inspection with you and other members of your staff. The results of this inspection are documented in the enclosed report.

Two findings of very low safety significance (Green) are documented in this report. One of these findings 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.

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 I; the Director, Office of Enforcement; and the NRC Resident Inspector at Beaver Valley Power Station, Units 1 and 2.

If you disagree with a finding not associated with a regulatory requirement 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 Beaver Valley Power 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, Matt R. Young, Chief Projects Branch 2 Division of Operating Reactor Safety

Docket Nos. 05000334 and 05000412 License Nos. DPR-66 and NPF-73

Enclosure:

As stated

Inspection Report

Docket Numbers:

05000334 and 05000412

License Numbers:

DPR-66 and NPF-73

Report Numbers:

05000334/2025001 and 05000412/2025001

Licensee:

Vistra Operations Company, LLC

Facility:

Beaver Valley Power Station, Units 1 and 2

Location:

Shippingport, PA

Inspection Dates:

January 1, 2025 to March 31, 2025

Inspectors:

N. Day, Senior Resident Inspector

L. Dumont, Senior Reactor Inspector

M. Fadden, Project Engineer

T. Fish, Senior Operations Engineer

N. Mentzer, Senior Project Engineer

A. Nugent, Resident Inspector

R. Rolph, Senior Health Physicist

Approved By:

Matt R. Young, Chief

Projects Branch 2

Division of Operating Reactor Safety

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Beaver Valley Power 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.

List of Findings and Violations

Unanalyzed Condition of Unit 1 Containment Due to Degraded River Water Piping Cornerstone Significance Cross-Cutting Aspect Report Section Barrier Integrity Green NCV 05000334/2025001-01 Open/Closed None (NPP)71152A A self-revealed Green finding and associated non-cited violation (NCV) of Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1 was identified when pinhole leaks were found in river water piping located inside containment, downstream of the 'A' and

'D' recirculation spray (RS) heat exchangers.

Manual Reactor Trip due to Loss of Steam Generator Water Level Control Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green FIN 05000334/2025001-02 Open/Closed None (NPP)71153 A self-revealed Green finding was identified when the licensee failed to implement established work control procedures for main feedwater regulation valve (MFRV) bypass valve

'A'. Specifically, not designating corrective maintenance appropriately resulted in the bypass valve failure and a loss of control of steam generator water level control which necessitated a manual reactor trip.

Additional Tracking Items

Type Issue Number Title Report Section Status LER 05000334/2024-004-00 LER 2024-004-00 for Beaver Valley Power Station, Unit 1,

Reactor Trip Due to Bypass Feedwater Regulating Valve Failure to Control 71153 Closed LER 05000334/2024-003-00 LER 2024-003-00 for Beaver Valley Power Station, Unit 1,

Unanalyzed Containment Bypass Condition Due to Degraded River Water Piping 71153 Closed

PLANT STATUS

Unit 1 started and remained at or near full rated power for the duration of the inspection period.

Unit 2 started the inspection period at full rated power. On February 5, 2025, the unit automatically tripped due to low steam generator level. Following maintenance on the 'B' MFRV, the unit was restarted on February 8, 2025. Unit 2 operated at or near rated thermal power 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

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 due to predicted cold weather conditions on January 10, 2025.

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 1, Quench spray train 'A' following performance of quench spray pump test per 1OST-13.1 on January 14, 2025

(2) Unit 1, Emergency diesel generator (EDG) 1-1 starting air system following performance of diesel generator monthly test per 1OST-36.1 on January 15, 2025

(3) Unit 2, Low head safety injection train 'A' on January 28, 2025

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 1, Safeguards Building 735' East Cable Vault, Fire Area CV-2 on January 16, 2025

(2) Unit 1, AE and DF Switchgear Rooms, Fire Areas ES-1 and ES-2 on February 12, 2025

(3) Unit 2, AE and DF Switchgear Rooms, Fire Areas 2ES-1 and 2ES-2 on February 12, 2025

(4) Unit 1, Fuel Building, Fire Area FB-1 on March 26, 2025

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 Beaver Valley Unit 2 licensed operator examination failure rates for the biennial written examinations administered January to February 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 unit 2 reactor trip on February 5, 2025.

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

(1) The inspectors observed and evaluated simulator scenarios for a rapid load reject, plant fire, and hostile action on January 28, 2025.

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 remain capable of performing their intended function:

(1) Systems discussed in Periodic Assessment Report of Maintenance Rule Program, approved on February 26, 2025, inspected on March 31, 2025

71111.13 - Maintenance Risk Assessments and Emergent Work Control

Risk Assessment and Management Sample (IP Section 03.01) (3 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, Startup activities on February 8, 2025

(2) Unit 1, Circulating water clamp repair in turbine building per temporary change TCC-1-32-TM-0001 on February 24, 2025

(3) Unit 2, Main turbine throttle valve TV-2 control circuitry repair management while at full power on February 26, 2025

71111.15 - Operability Determinations and Functionality Assessments

Operability Determination or Functionality Assessment (IP Section 03.01) (6 Samples)

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

(1) Unit 1, Quench spray pump A suction line through wall leak as described in condition report (CR)-2025-00331 on January 1, 2025

(2) Unit 1, operability impact associated with 1P 480V emergency bus degraded voltage relay test per 1MSP-36.44-E performed on January 27, 2025

(3) Unit 2, Mode 2 readiness on February 7, 2025

(4) Unit 2, Control Rod F14 rod bottom stuck position as described in CR-2025-00840 on February 7, 2025

(5) Unit 1, RS heat exchanger outlet valve C failing to indicate closed and impact to closed system inside containment as described in CR-2025-01770 on March 17, 2025

(6) Unit 2, Steam generator B operational decision making instruction BV2-25-01 on March 20, 2025

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 1, Post-calibration testing of the 1DF 4KV emergency bus diesel start loss of voltage relay, and associated time delay relay, per 1MSP-36.54A-E and 1MSP-36.54B-E on January 2, 2025

(2) Unit 2, Steam generator B MFRV following arm reattachment with Loctite, per Work Order (WO) 200966295 on February 8, 2025

(3) Unit 1, Valve strokes following repair of MOV-1RW-104C to address failure to indicate shut as described in CR-2025-01770 on March 18, 2025

(4) Unit 1, Low head safety injection pump A following motor preventative maintenance per 1OST-47.3L and 1OST-43.11.1s on February 18, 2025

(5) Unit 2, High head safety injection pump B following motor preventative maintenance per 2OST-7.5 on March 25, 2025

Surveillance Testing (IP Section 03.01) (3 Samples)

(1) Unit 1, Quench spray pump A quarterly test per 1OST-13.1 on January 13, 2025

(2) Non-licensed operator rounds in the Unit 2 turbine building on January 31, 2025

(3) Unit 1, Motor Driven Aux Feedwater Pump B surveillance test per 1OST-24.03 on March 4, 2025

Diverse and Flexible Coping Strategies (FLEX) Testing (IP Section 03.02) (1 Sample)

(1) Surveillance test of FLEX Auxiliary Feedwater Pumps performed on January 27, 2025

71114.06 - Drill Evaluation

Required Emergency Preparedness Drill (1 Sample)

(1) Gold team hostile action emergency drill on February 20,

71124.03 - In-Plant Airborne Radioactivity Control and Mitigation

Permanent Ventilation Systems (IP Section 03.01) (1 Sample)

The inspectors evaluated the configuration of the following permanently installed ventilation systems:

(1) Unit 2, Control room normal and emergency ventilation system

Temporary Ventilation Systems (IP Section 03.02) (1 Sample)

The inspectors evaluated the configuration of the following temporary ventilation systems:

(1) The portable ventilation unit, SP700 #40 in the potentially contaminated area shop decontamination room

Use of Respiratory Protection Devices (IP Section 03.03) (1 Sample)

(1) The inspectors evaluated the licensees use of respiratory protection devices.

Self-Contained Breathing Apparatus for Emergency Use (IP Section 03.04) (1 Sample)

(1) The inspectors evaluated the licensees use and maintenance of self-contained breathing apparatuses.

71124.04 - Occupational Dose Assessment

Source Term Characterization (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated licensee performance as it pertains to radioactive source term characterization.

External Dosimetry (IP Section 03.02) (1 Sample)

(1) The inspectors evaluated how the licensee processes, stores, and uses external dosimetry.

Internal Dosimetry (IP Section 03.03) (2 Samples)

The inspectors evaluated the following internal dose assessments:

(1) Unit 2, Containment Entry on May 29, 2024, for internal dose assessment for H3

(2) Unit 2, Containment Entry on May 30, 2024, for internal dose assessment for H3

Special Dosimetric Situations (IP Section 03.04) (2 Samples)

The inspectors evaluated the following special dosimetric situations:

(1) Declared Pregnant Worker ID 23625

(2) Declared Pregnant Worker ID

OTHER ACTIVITIES - BASELINE

===71151 - Performance Indicator Verification

The inspectors verified licensee performance indicators submittals listed below:

IE01: Unplanned Scrams per 7000 Critical Hours Sample (IP Section 02.01)===

(1) Unit 1 (January 1 through December 31, 2024)

(2) Unit 2 (January 1 through December 31, 2024)

IE03: Unplanned Power Changes per 7000 Critical Hours Sample (IP Section 02.02) (2 Samples)

(1) Unit 1 (January 1 through December 31, 2024)

(2) Unit 2 (January 1 through December 31, 2024)

IE04: Unplanned Scrams with Complications (USwC) Sample (IP Section 02.03) (2 Samples)

(1) Unit 1 (January 1 through December 31, 2024)

(2) Unit 1 (January 1 through December 31, 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 the completed and planned corrective actions per CR-2024-

===04203 to prevent recurrence, as well as the root cause evaluation associated with the Unit 1 containment condition prohibited by TS discovered on May 8, 2024, associated with a Green NCV in the Barrier Integrity cornerstone. This is documented in the Inspection Results 71152A section in this report. The inspectors verified corrective actions are established with appropriate completions scheduled.

2)

The inspectors reviewed CR-2024-01407 and corrective action procedures to assess the effectiveness of the licensee in prioritizing and evaluating the unplanned Unit 2 rod drive power supply motor generator (MG) output breaker trip. In addition, the inspectors reviewed the licensee preventive maintenance related to the MG sets associated components to verify that maintenance was effective, so that the MG sets will perform their intended function when required. The inspectors verified these corrective actions had been completed as scheduled.

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 2024-003-00, Unanalyzed Condition Due to Degraded River Water Piping (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24185A033). Through a past operability review, the licensee determined that a condition prohibited by TS existed. The inspectors documented a Green NCV due to the failure to meet the Technical Specification Limiting Condition for Operation for containment. This violation is documented in the results sections of 71152A of this report. This LER is Closed.

(2) LER 2024-004-00, Reactor Trip Due to Bypass Feedwater Regulating Valve Failure to Control (ML24199A242). Through a work history review, the inspectors determined that a performance deficiency existed. The inspectors documented a Green finding due to inadequate execution of licensee's work control procedures. The inspection conclusions associated with this LER are documented in this report under Inspection Results Section 71153. This LER is Closed.

Personnel Performance (IP Section 03.03) (1 Sample)

(1) The inspectors evaluated the Unit 2 reactor trip due to low steam generator B water level and licensees performance on February 5,

INSPECTION RESULTS

Unanalyzed Condition of Unit 1 Containment Due to Degraded River Water Piping Cornerstone Significance Cross-Cutting Aspect Report Section Barrier Integrity

Green NCV 05000334/2025001-01 Open/Closed

None (NPP)71152A A self-revealed Green finding and associated NCV of Technical Specifications Limiting Condition of Operation 3.6.1 was identified when pinhole leaks were found in river water piping located inside containment, downstream of the 'A' and 'D' RS heat exchangers.

Description:

On May 9, 2024, during a Unit 1 refueling outage, a pinhole leak was identified on the river water piping inside containment, on the outlet side of the 'D' RS heat exchanger during a Type B pressure test of the adjacent mechanical expansion joint. An extent of condition evaluation was performed on the remaining trains, through which a similar leak was discovered on the river water piping downstream of the 'A' RS heat exchanger.

This piping is operated at vacuum when the RS system is in service. This portion of the piping is considered a closed system inside containment, and there are isolation valves downstream of the leaks, outside of containment. These valves remain open upon both a containment isolation 'A' and containment isolation 'B' signal. This allows river water flow through the RS system, to maintain containment parameters during a design basis accident. Therefore, due to these leaks in the river water piping, a bypass path was created through containment. The licensee determined the cumulative area to be approximately 1.5 square inches. In the event of a gaseous release, operators would be able to detect and manually shut the heat exchanger isolation valves to stop the release. However, given that two of the RS heat exchangers would be isolated, an additional failure of a single component could prevent maintaining containment temperature within limits. This results in a containment bypass condition and unanalyzed condition.

These leaks were similar to a previous leak found on the outlet of the 'C' RS heat exchanger river water piping on October 22, 2019. As a corrective action, the leak was repaired using a welded cap. The inspectors note this as prior plant experience.

Step 7.3.1 of licensee procedure 1/2-ADM-2106, River/Service Water System Control and Monitoring Program, Revision 0, states that "the River/Service Water System Engineer recommends locations to be examined by NDE methods by the NDE Group in accordance with Engineering Standard M-032, River/Service Water Inspection Monitoring Program." Step 2.4.1 of Engineering Standard M-032, Revision 3 states, in part, that, "Engineering judgment, industry and prior plant experience... may be used as a guide to select locations for examination of piping for long term monitoring of pipe wall thickness"

Corrective Actions: The licensee performed an immediate action of performing a weld buildup repair of the A outlet piping, and a pipe replacement on the D piping in order to return the system to service.

The licensee performed a root cause evaluation, which attributed the degradation to a failure by the organization to recognize the potential for a containment vulnerability due to a leak in the RS heat exchanger river water outlet piping. This recognition should have directed the licensee to establish programmatic requirements to monitor and when needed, repair or replace any degraded sections of this piping.

To prevent recurrence, this piping will be replaced over the next several refueling outages.

Additionally, the licensee has established a monitoring and replacement program for the Unit 1 RS heat exchanger river water outlet piping, where wall thickness will be monitored on river water piping between the containment structure and the RS heat exchangers.

Corrective Action References: CR-2019-08787, CR-2024-04129, CR-2024-04143, and CR-2024-04203

Performance Assessment:

Performance Deficiency: The licensee's failure to use prior plant experience as a guide to select locations for examination of river water piping for long term monitoring of pipe thickness is a performance deficiency. Specifically, after the leak found in 2019 was repaired, the licensee failed to use this plant experience to establish a monitoring program for the Unit 1 RS heat exchanger river water outlet piping in accordance with Engineering Standard M-032, as referenced in 1/2-ADM-2106.

Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Human Performance attribute of the Barrier Integrity cornerstone and adversely affected the cornerstone objective to provide reasonable assurance that physical design barriers protect the public from radionuclide releases caused by accidents or events. The performance deficiency was also associated with the Equipment Performance attribute of the Mitigating Systems cornerstone. However, the inspectors determined that the Barrier Integrity cornerstone was impacted more significantly as evaluated per the Significance Determination Process (SDP) in IMC 0609, Appendix A.

Significance: The inspectors assessed the significance of the finding using IMC 0609, Appendix A, The Significance Determination Process for Findings At-Power, and IMC 0609, Appendix H, Containment Integrity SDP. Per table 4.1 of IMC 0609, Appendix H, in regards to failure of containment isolation valves in lines connected to closed systems inside/outside containment, small lines (<1-2 inch diameter) and lines connecting to closed systems would not generally contribute to large early release frequency (LERF). This is congruent with the licensee risk evaluation performed per PRA-BV3-09-001, Revision 0, which was reviewed by the inspectors, and states that a nominal value of an equivalent 2 inch diameter hole size in containment be used as the minimum opening size for LERF for Beaver Valley Unit 1.

Cumulatively, the pinhole leaks found in the river water piping constituted an equivalent 1.5 square inches of surface area, which can be equated to a hole approximately 0.7 inches in diameter. Therefore, the inspectors determined the finding to be of very low safety significance (Green).

Cross-Cutting Aspect: Not Present Performance. No cross-cutting aspect was assigned to this finding because the inspectors determined the finding did not reflect present licensee performance.

Enforcement:

Violation: Technical Specifications Limiting Condition for Operation 3.6.1 requires that containment must be operable in Modes 1, 2, 3, and 4.

Contrary to the above, from November 16, 2022, to April 13, 2024, during the periods Beaver Valley Unit 1 was in Mode 1, 2, 3, and 4, Unit 1 containment was inoperable and Technical Specifications Limiting Condition for Operation 3.6.1 was not met due to the river water pinhole leaks providing a bypass path through containment.

Enforcement Action: This violation is being treated as an NCV, consistent with Section 2.3.2 of the Enforcement Policy.

Observation: Rod Drive Power Supply MG Set 22 Generator Output Breaker Tripped 71152A On February 8, 2024, Beaver Valleys rod drive MG sets 21 and 22 were operated in parallel to power the rod control system (each rod drive MG set is 100% capacity). Then, rod drive power supply MG set 22 generator output breaker tripped on over current trip switch phase C due to an actuation of the directional overcurrent (IRV) with rod drive MG set 22 output breaker open. Following extensive troubleshooting, the licensee identified the cause as a failed resistor, a subcomponent in the MG set.

The inspectors reviewed CR-2024-01407 and corrective action program procedures to assess the effectiveness of the licensee in prioritizing and evaluating the issue. This sample was selected based on the rod drive MG set potential to result in a reactor trip. The inspectors reviewed the licensee preventive maintenance related to the MG sets associated components to verify that licensee preventive maintenance was effective. The inspectors noted that the MG set was refurbished every 12 years, and the voltage regulator associated with the MG set was replaced on a 15-year frequency. In addition, the inspectors performed visual inspection of rod drive MG set 22 during operation. During the inspection, rod drive MG set 22 was running in parallel with rod drive MG set 21. Finally, the inspectors reviewed the post-maintenance testing of rod drive MG set 21. No issues were identified.

The inspectors did not identify any performance deficiency. The licensee had preventive maintenance in place and the licensee did not have any operating experiences associated with the issue. The inspectors concluded that the cause of the MG set trip was not reasonably within the licensees ability to foresee and correct it.

Manual Reactor Trip due to Loss of Steam Generator Water Level Control Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events

Green FIN 05000334/2025001-02 Open/Closed

None (NPP)71153 A self-revealed Green finding was identified when the licensee failed to implement established work control procedures for MFRV bypass valve 'A'. Specifically, not designating corrective maintenance appropriately resulted in the bypass valve failure and a loss of control of steam generator water level control which necessitated a manual reactor trip.

Description:

On October 7, 2021, preventative maintenance was performed on Unit 1 steam generator MFRV bypass valve 'A' (1FW-FCV-479), which included an air leak test of the valve actuator. The test indicated air leakage which was documented in CR-2021-07499.

Licensee staff evaluated the air leak rate and determined it did not challenge valve operation in the near term. This determination was supported by similar history on an identical valve for a separate steam generator (1FW-FCV-499). Licensee staff closed CR-2021-07499 with no recommended action based on the scheduled performance of the preventative maintenance in July 2023, as tracked by WO 200774278. Licensee procedure NOP-WM-1003, Nuclear Maintenance Notification Initiation and Screening, requires a notification added to the WO to track the correction of the identified issue via preventative maintenance. Instead, licensee staff added a note to WO 200774278 and sent an email to work scheduling, which did not formally delineate using a preventative maintenance activity to perform corrective maintenance.

Performance of WO 200774278 was rescheduled until the end of 2024, in order to minimize time that the valve would be out of service and allow for additional maintenance to be done simultaneously. The work scheduling group did not see a notification on the WO that would have alerted them to the need to perform the work as scheduled. This informal note added to WO 200774278, which might have prevented the delay, was not recognized, as notifications are the formal process.

On May 18, 2024, at 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br />, operators at Beaver Valley Unit 1 began increasing reactor power to return to full power following refueling outage 1R29. Operators observed lowering steam generator A water levels due to 1FW-FCV-479 not responding to regulate feedwater flow in automatic control. 1FW-FCV-479 did not respond as expected due to binding in the actuator or toggle assembly, which is normally overcome by the differential pressure developed in the actuator. Due to the excessive air leakage, the required differential pressure could not be developed in the actuator. Operators attempted manual remote and local valve control of the valve to attempt to restore steam generator water level but were unsuccessful.

Steam generator water level continued to lower to the previously established administrative steam generator low level manual trip limit and operators performed a manual reactor trip.

Corrective Actions: Licensee performed a failure mode analysis and troubleshooting of 1FW-FCV-479. The air leak was repaired and boosters tuned to restore the valve to service for the subsequent startup.

Corrective Action References: CR-2024-04528, CR-2025-02148

Performance Assessment:

Performance Deficiency: The failure to adhere to procedures for assigning and scheduling maintenance is a performance deficiency. Specifically, licensee staff did not initiate a notification in accordance with procedure NOP-WM-1003 when work was identified in 2021.

As a result, 1FW-FCV-479 did not perform as expected while in service, which resulted in loss of steam generator water level control and necessitated a manual reactor trip.

Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Human Performance attribute of the Initiating Events cornerstone and adversely affected the cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations.

Significance: The inspectors assessed the significance of the finding using IMC 0609, Appendix A, The SDP for Findings At-Power. Specifically, the feedwater transient necessitated a manual reactor trip but did not result in the loss of mitigation equipment relied upon to transition the plant from the onset of the trip to a stable shutdown condition.

Therefore, the inspectors determined the finding to be of very low safety significance (Green).

Cross-Cutting Aspect: Not Present Performance. No cross-cutting aspect was assigned to this finding because the inspectors determined the finding did not reflect present licensee performance.

Enforcement:

Inspectors did not identify a violation of regulatory requirements associated with this finding.

EXIT MEETINGS AND DEBRIEFS

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

• On April 22, 2025, the inspectors presented the integrated inspection results to Barry Blair, Site Vice President, and other members of the licensee staff.

• On January 30, 2025, the inspectors presented the 71124.03 and 71124.04 inspection results to Bob Kristophel, Plant Manager, and other members of the licensee staff.

• On February 13, 2025, the inspectors presented the rod drive power supply MG set 22 generator output breaker tripped inspection results to Michael Jansto, Principal Nuclear Engineer Regulatory Compliance, and other members of the licensee staff.

DOCUMENTS REVIEWED

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

71152A

Corrective Action

Documents

CR-2024-01047

CR-2023-06659

CR-2023-03586

CR-2024-01136

Miscellaneous

2DBD-01

Design Basis Document for Reactor Control and Protection

System

NORM-ER-1202

480 V Motor Repair Specification

Procedures

2OM-1.4.B

Reactor Rod Drive Control System Startup

BVPM-ER-3004

Maintenance Rule (MR) Program Supplemental Guidance

NOBP-ER-3901

Component Classification ER Workbench Module 1

Work Orders

200963243