IR 05000259/2024004

Integrated Inspection Report 05000259/2024004 and 05000260/2024004 and 05000296/2024004

ML25028A120
Person / Time
Site:	Browns Ferry   (DPR-033, DPR-052, DPR-068)
Issue date:	01/31/2025
From:	Louis Mckown NRC/RGN-II/DORS/PB5
To:	Erb D Tennessee Valley Authority
References
IR 2024004
Download: ML25028A120 (1)

Text

SUBJECT:

BROWNS FERRY NUCLEAR PLANT - INTEGRATED INSPECTION REPORT 05000259/2024004 AND 05000260/2024004 AND 05000296/2024004

Dear Delson Erb:

On December 31, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Browns Ferry Nuclear Plant. On January 14, 2025, the NRC inspectors discussed the results of this inspection with Daniel Komm, 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. One Severity Level IV violation without an associated finding is documented in this report. We are treating these violations as non-cited violations (NCVs) 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 II; the Director, Office of Enforcement; and the NRC Resident Inspector at Browns Ferry Nuclear Plant.

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 II; and the NRC Resident Inspector at Browns Ferry Nuclear Plant.

January 31, 2025 This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.

Sincerely, Louis J. McKown, II, Chief Projects Branch 5 Division of Operating Reactor Safety Docket Nos. 05000259 and 05000260 and 05000296 License Nos. DPR-33 and DPR-52 and DPR-68

Enclosure:

As stated

Inspection Report

Docket Numbers:

05000259, 05000260 and 05000296

License Numbers:

DPR-33, DPR-52 and DPR-68

Report Numbers:

05000259/2024004, 05000260/2024004 and 05000296/2024004

Enterprise Identifier:

I-2024-004-0013

Licensee:

Tennessee Valley Authority

Facility:

Browns Ferry Nuclear Plant

Location:

Athens, Alabama

Inspection Dates:

October 01, 2024, to December 31, 2024

Inspectors:

S. Billups, Resident Inspector

D. Lanyi, Senior Operations Engineer

K. Pfeil, Resident Inspector

K. Schaaf, Operations Engineer

T. Steadham, Senior Resident Inspector

F. Young, Resident Inspector

Approved By:

Louis J. McKown, II, Chief

Projects Branch 5

Division of Operating Reactor Safety

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Browns Ferry Nuclear Plant, 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

Failure to Control Gaseous Fire Suppression Boundary Penetration Breaches Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000259,05000260,05000296/202400 4-01 Open/Closed

[H.5] - Work Management 71111.05 The inspectors identified a Green non-cited violation (NCV) of Unit 1, 2, and 3 Operating License Condition 2.C.(13), 2.C.(14), and 2.C.(7), respectively, for the licensees failure to control the breaching of carbon dioxide boundaries in the Units 1, 2, and 3 standby diesel generator buildings. As a result, the associated carbon dioxide fire suppression systems were non-functional until the licensee took appropriate corrective actions in response to the inspectors' concerns, such as implementing the required compensatory measures and sealing the penetrations.

Main Steam Relief Valves Lift Settings Outside of Technical Specification Required Setpoints Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NCV 05000296/2024004-02 Open/Closed Not Applicable 71153 A self-revealed Severity Level IV NCV of Technical Specification (TS) 3.4.3 and TS 3.0.4 was identified when the licensee discovered, through as found test results, that four of thirteen Main Steam Relief Valves (MSRVs) that were removed for testing had as found lift settings outside of the +/-3 percent setpoint band required for their operability.

Additional Tracking Items

None.

PLANT STATUS

Unit 1 began the inspection period at 88 percent rated thermal power (RTP) for power ascension following refueling outage 1R15. The unit achieved full RTP (100%) on October 2, 2024. On October 3, 2024, operators lowered reactor power to 65 percent RTP for a control rod pattern adjustment. On October 3, 2024, the unit was returned to 100 percent RTP. On November 16, 2024, operators lowered power to 60% for a control rod sequence exchange. On November 17, 2024, the unit was returned to 100 percent RTP where it remained at or near for the remainder of the inspection period.

Unit 2 began the inspection period at full RTP. On October 13, 2024, reactor power was lowered to 27 percent RTP following a trip of the Unit 2A reactor recirculation pump. Following repairs, the unit was returned to 100 percent RTP on October 16, 2024. On October 26, 2024, operators lowered reactor power to 66 percent RTP for a control rod pattern adjustment. On October 27, 2024, the unit was returned to 100 percent RTP. On November 23, 2024, operators lowered reactor power to 60 percent RTP to repair a reactor water cleanup pipe leak and a reactor core isolation cooling motor operated valve motor that was affected by the leak. Following repairs, the unit was returned to 100 percent RTP on November 24, 2024. On November 25, 2024, operators lowered reactor power to 76 percent RTP for a control rod pattern adjustment. On November 26, 2024, the unit was returned to 100 percent RTP. On December 8, 2024, operators lowered reactor power to 77 percent RTP for a control rod pattern adjustment. On December 9, 2024, the unit was returned to 100 percent RTP. On December 27, 2024, operators reduced power to 80 percent RTP for a control rod pattern adjustment. On December 28, 2024, the unit was returned to 100 percent RTP where it remained at or near for the remainder of the inspection period.

Unit 3 began the inspection period at full RTP. On October 4, 2024, operators lowered reactor power to 17 percent RTP and manually scrammed the unit for forced outage F313 to correct the cause of increased unidentified drywell leakage. Following repairs, operators started up the unit on October 11, 2024. On October 16, 2024, the unit was returned to 100 percent RTP. On December 15, 2024, operators lowered reactor power to 65 percent RTP for a control rod sequence exchange. On December 16, 2024, the unit was returned to 100 percent RTP where it remained at or near 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.

71111.05 - Fire Protection

Fire Area Walkdown and Inspection Sample (IP Section 03.01) (2 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 3 control air conditioner mechanical equipment room on November 4, 2024

(2) Unit 3 emergency diesel generator 3A, 3B, 3C, and 3D rooms elevation 565' on December 19, 2024

71111.11A - Licensed Operator Requalification Program and Licensed Operator Performance

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

The licensee completed the annual requalification operating examinations and biennial written examinations required to be administered to all licensed operators in accordance with Title 10 of the Code of Federal Regulations 55.59(a)(2), "Requalification Requirements," of the NRC's "Operator's Licenses." The inspector performed an in-office review of the overall pass/fail results of the individual operating examinations, the crew simulator operating examinations, and the biennial written examinations in accordance with Inspection Procedure (IP) 71111.11, "Licensed Operator Requalification Program and Licensed Operator Performance." These results were compared to the thresholds established in Section 3.03, "Requalification Examination Results," of IP 71111.11.

(1) The inspectors reviewed and evaluated the licensed operator examination failure rates for the requalification annual operating exam administered on December 4, 2024.

71111.11B - Licensed Operator Requalification Program and Licensed Operator Performance

Licensed Operator Requalification Program (IP Section 03.04) (1 Sample)

An inspection was performed to assess the effectiveness of the facility licensee in implementing requalification requirements identified in 10 CFR Part 55, Operators Licenses. Each of the following inspection activities was conducted in accordance with IP

===71111.11, Licensed Operator Requalification Program and Licensed Operator Performance.

(1) Biennial Requalification Written Examinations The inspectors evaluated the quality of the licensed operator biennial requalification written examination administered on November 2023.

Annual Requalification Operating Tests The inspectors evaluated the adequacy of the facility licensees annual requalification operating test.

Administration of an Annual Requalification Operating Test The inspectors evaluated the effectiveness of the facility licensee in administering requalification operating tests required by 10 CFR 55.59(a)(2) and that the facility licensee is effectively evaluating their licensed operators for mastery of training objectives.

Requalification Examination Security The inspectors evaluated the ability of the facility licensee to safeguard examination material, such that the examination is not compromised.

Remedial Training and Re-examinations The inspectors evaluated the effectiveness of remedial training conducted by the licensee, and reviewed the adequacy of re-examinations for licensed operators who did not pass a required requalification examination.

Operator License Conditions The inspectors evaluated the licensees program for ensuring that licensed operators meet the conditions of their licenses.

Control Room Simulator The inspectors evaluated the adequacy of the facility licensees control room simulator in modeling the actual plant, and for meeting the requirements contained in 10 CFR 55.46.

71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance

Licensed Operator Requalification Training/Examinations (IP Section 03.02)===

(1) The inspectors observed and evaluated a licensed operator requalification training session in the simulator which included an inadvertent reactor core isolation cooling pump injection, a trip of a reactor building closed cooling water pump, a failed reactor pressure vessel level transmitter leading to a half scram, loss of a 480V shutdown board, a failure of all control rods to insert on a scram, and a steam leak inside the drywell on November 5, 2024. This training session required the crew to enter various abnormal operating instructions, emergency operating instructions, and emergency plan implementing procedures to control the plant and appropriately classify the emergency.

(2) The inspectors observed and evaluated a licensed operator requalification training session in the simulator which included a condensate pump trip, main steam relief valve inadvertent opening, loss of a 480V reactor motor operated valve board, a station blackout, emergency high pressure makeup pump failure, and the failure of high pressure coolant injection to automatically start on November 5, 2024. This training session required the crew to enter various abnormal operating instructions, emergency operating instructions, and emergency plan implementing procedures to control the plant and appropriately classify the emergency.

(3) The inspectors observed and evaluated a licensed operator requalification training session in the simulator which included a high pressure coolant injection inadvertent initiation, loss of a 4KV unit board, loss of a control rod drive pump, an anticipated transient without scram, and a torus water leak on November 5, 2024. This training session required the crew to enter various abnormal operating instructions, emergency operating instructions, and emergency plan implementing procedures to control the plant and appropriately classify the emergency.

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) Maintenance rule monitoring program periodic assessment report review on October 29, 2024

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) Maintenance risk during common unit residual heat removal service water pump A2 was unavailable due to planned maintenance on October 29, 2024

(2) Emergent work control during Unit 2 reactor core isolation cooling turbine unavailability on November 20, 2024

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) CR 1962832, main steam relief valve pilot disc procedure inconsistencies on October 10, 2024

(2) CR 1965693 & 1965792, Units 1 & 2 main control room air handling units 1A and 1B inoperable on October 16, 2024

(3) CR 1965828, through wall leak on Unit 3 reactor recirculation pump 3B discharge pressure sensing line on October 24, 2024

(4) CR 1968863, Unit 2 scram discharge volume indication on panel 2-9-5 not illuminated on October 31, 2024

(5) CR 1971949, Unit 2 high pressure coolant injection discharge check valve reseated on November 18, 2024

(6) CR 1977118, Unit 1 reactor core isolation cooling barometric condenser vacuum pump not developing expected pressure on December 12, 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) BFN-23-029, Install blind flange in demineralized water supply for Unit 1 standby liquid control system on December 16, 2024

71111.20 - Refueling and Other Outage Activities

Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated various Unit 3 forced outage F313 activities from October 4, 2024, through October 11, 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) (4 Samples)

(1) WO 123153734, common unit train C standby gas treatment filter pressure drop and in-place leak test after maintenance on October 11, 2024

(2) WO 124871621, repair pressure boundary leak on Unit 3 reactor recirculation pump 3B discharge pressure sensing line on October 18, 2024

(3) WO 123526028, Unit 1 reactor core isolation cooling high pressure flow test following system maintenance on October 30, 2024

(4) WO 124963499, Unit 2 replacement of reactor core isolation cooling steam line outboard isolation valve actuator motor on December 10, 2024

Surveillance Testing (IP Section 03.01) (1 Sample)

(1) WO 123485047, Unit 2 high pressure coolant injection pump quarterly flowrate surveillance test on November 12, 2024

Reactor Coolant System Leakage Detection Testing (IP Section 03.01) (1 Sample)

(1) Unit 3 drywell unidentified leakage testing from June 3, 2024, through October 4,

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

(2) Unit 2 (October 1, 2023, through September 30, 2024)

(3) Unit 3 (October 1, 2023, through September 30, 2024)

IE03: Unplanned Power Changes per 7000 Critical Hours Sample (IP Section 02.02) (3 Samples)

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

(2) Unit 2 (October 1, 2023, through September 30, 2024)

(3) Unit 3 (October 1, 2023, through September 30, 2024)

IE04: Unplanned Scrams with Complications (USwC) Sample (IP Section 02.03) (3 Samples)

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

(2) Unit 2 (October 1, 2023, through September 30, 2024)

(3) Unit 3 (October 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) Licensee identification and monitoring of increased Unit 3 drywell leakage between June 3, 2024, and October 4, 2024, including identification of the cause and corrective actions to repair the identified leaks on October 24, 2024

(2) CR 1962832, Corrective actions to address repeat main steam relief valves pilot disc failures on October 31, 2024

(3) CR 1769257, Unit 1 1A residual heat removal service water heat exchanger outlet valve breaker tripped while closing the valve from main control room on November 21, 2024

(4) CR 1892410, Corrective actions to address previous Unit 1 standby liquid control inadvertent dilution events on December 10, 2024

(5) CR 1911843, Gross leakage through Unit 3 penetration 3-X-11 outboard valves on December 12, 2024

71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02)

(1) The inspectors performed a review of potential adverse trends in procurement document control 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 licensees event reporting determinations to ensure it complied with reporting requirements.

(1) LER 2024-001-01 for Browns Ferry Nuclear Plant, Units 1, 2, and 3, Inoperability of Unit 3 Diesel Generator due to Relay Failure (ADAMS Accession No.

ML24185A151). The inspectors determined that this LER was a revision to an LER previously reviewed in inspection report 05000259/2024002 and 05000260/2024002 and 05000296/2024002 (ADAMS Accession No. ML24214A167). No additional violations or findings were identified as a result of this review. This LER is Closed.

(2) LER 2024-001-02 for Browns Ferry Nuclear Plant, Units 1, 2, and 3, Secondary Containment Isolation Valve Inoperable due to Mechanical Failure (ADAMS Accession No. ML24302A223). The inspectors determined that this LER was a revision to an LER previously reviewed in inspection report 05000259/2024002 and 05000260/2024002 and 05000296/2024002 (ADAMS Accession No.

ML24214A167). No additional violations or performance deficiencies were identified as a result of this review. This LER is Closed.

(3) LER 2024-002-00 for Browns Ferry Nuclear Plant, Unit 2, High Pressure Coolant Injection Inoperable due to Rupture Disc Failure and Resulting System Isolation (ADAMS Accession No. ML24141A246). The inspectors determined that this LER was related to a White performance deficiency and associated violation previously dispositioned in inspection report 0500260/2024090. No additional violations or findings were identified as a result of this LER review. This LER is Closed.

(4) LER 2024-002-01 for Browns Ferry Nuclear Plant, Unit 2, High Pressure Coolant Injection Inoperable due to Rupture Disc Failure and Resulting System Isolation (ADAMS Accession No. ML24330A077). The inspectors determined that this LER was a revision to an LER previously reviewed in this inspection report. No additional violations or findings were identified as a result of this LER review. This LER is Closed.

(5) LER 2024-003-00 for Browns Ferry Nuclear Plant, Unit 3, Main Steam Relief Valves Lift Settings Outside of Technical Specifications Required Setpoints (ADAMS Accession No. ML2490A129). The inspectors determined that it was not reasonable to foresee or correct the cause discussed in the LER therefore no performance deficiency was identified. The inspectors determined that this LER was related to a SL IV NCV violation that is documented in the violations section of this report. This LER is Closed.

INSPECTION RESULTS

Failure to Control Gaseous Fire Suppression Boundary Penetration Breaches Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000259,05000260,05000296/20240 04-01 Open/Closed

[H.5] - Work Management 71111.05 The inspectors identified a Green non-cited violation (NCV) of Unit 1, 2, and 3 Operating License Condition 2.C.(13), 2.C.(14), and 2.C.(7), respectively, for the licensees failure to control the breaching of carbon dioxide boundaries in the Units 1, 2, and 3 standby diesel generator buildings. As a result, the associated carbon dioxide fire suppression systems were non-functional until the licensee took appropriate corrective actions in response to the inspectors' concerns, such as implementing the required compensatory measures and sealing the penetrations.

Description:

On December 16, 2024, the inspectors identified open electrical boxes inside the Unit 3 diesel generator rooms 3A, 3B, 3C, and 3D. These boxes were connected to 3/4 conduit that breached the carbon dioxide (CO2) barrier for each diesel generator room in two places - through the east wall into the common pipe tunnel and through the ceiling into the respective diesel exhaust fan room. For all eight penetrations, the unsealed conduit was open on both sides of the CO2 boundary providing an uncontrolled pathway past each of the four boundaries which was equivalent to a single 1.06 diameter hole in the CO2 boundary for each diesel generator room CO2 barrier. The function of the CO2 barrier is to maintain a sufficient CO2 concentration in the room to ensure sufficient fire suppression and with the unsealed penetrations, the functionality of the CO2 barrier for each Unit 3 standby diesel generator was adversely affected. During the extent of condition review for this concern, the licensee identified a similar condition for all four Unit 1/2 standby diesel generators and the Unit 1/2 diesel auxiliary board room B. For all four Unit 1/2 standby diesel generators, a single 3/4" unsealed conduit was open in both the diesel generator room and the other side of the CO2 boundary in each diesel generator's respective fan room. In addition, a single unsealed conduit breached the CO2 boundary for the Unit 1/2 diesel auxiliary board room B that was likewise open on both sides of the boundary.

The following areas protected by CO2 suppression systems were affected:

• BFN-0-SUPR-039-0007/20A, Unit 1/2 diesel generator room A

• BFN-0-SUPR-039-0008/20B, Unit 1/2 diesel generator room B

• BFN-0-SUPR-039-0009/20C, Unit 1/2 diesel generator room C

• BFN-0-SUPR-039-0010/20D, Unit 1/2 diesel generator room D

• BFN-0-SUPR-039-0006/20E, Unit 1/2 diesel auxiliary board room B

• BFN-0-SUPR-039-0038/21A, Unit 3 diesel generator room 3A

• BFN-0-SUPR-039-0039/21B, Unit 3 diesel generator room 3B

• BFN-0-SUPR-039-0040/21C, Unit 3 diesel generator room 3C

• BFN-0-SUPR-039-0041/21D, Unit 3 diesel generator room 3D These conduits were being installed for an ongoing plant modification under work order 124867684 which was originally signed on to begin work on November 1, 2024. The licensee did not flag this work order as needing a fire protection impairment because the impact on the CO2 barriers was not identified when the work order was planned. Hence, during the work order planning stage, the fire protection group did not review the planned work for any potential impacts on the fire protection program. As such, the installation of the conduit resulted in breaches to the CO2 boundaries that were outside of the existing fire protection configuration control program. Upon further review, the conduit was installed in previously sealed spare two-inch penetrations. As such, conservatively assuming that at most a total of two 2" openings existed for any one CO2 boundary, this would be equal to a single 2.83" diameter hole. Because the work order did not have proper controls on the CO2 boundary breaches, the original opening of the applicable spare penetrations was likewise uncontrolled and represented a larger breach than the unsealed conduits that the inspectors discovered. When the inspectors identified this issue to the licensee, the Fire Protection group immediately identified these conduits as an uncontrolled CO2 boundary breach. Because of this, the inspectors concluded that it was reasonable to believe that had Fire Protection been consulted during the planning stages of the work order, the CO2 boundary impact likely would have been identified.

Browns Ferry Nuclear Fire Protection Requirements Manual, Revision 26, Section 9.3.11.D, CO2 Systems, requires, that CO2 systems are considered non-functional if penetration(s) of the enclosure protected by CO2 are breached outside of existing configuration control. Based on this, the licensee declared the affected CO2 systems non-functional and implemented a roving fire watch consistent with Table T9.3.11.D-1 of the Fire Protection Requirements Manual. Craft personnel sealed the conduits on December 18, 2024, which restored the functionality of the CO2 boundaries for all eight diesel generator rooms and the Unit 1/2 diesel auxiliary board room B.

Corrective Actions: The licensee implemented an hourly fire watch until craft personnel sealed the affected penetrations and restored the CO2 boundaries. Training was conducted with craft personnel on identifying work that can impact the functionality of a CO2 boundary.

Corrective Action References: CR 1979883

Performance Assessment:

Performance Deficiency: The failure to control the breaching of nine CO2 boundaries in the Unit 1, 2, and 3 standby diesel generator buildings was contrary to the fire protection program and was a performance deficiency.

Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Protection Against External Factors attribute of the Mitigating Systems cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the unsealed penetrations rendered the CO2 systems associated with the Units 1, 2, and 3 standby diesel generators non-functional which is consistent with the more than minor criteria for Example 2.d in Inspection Manual Chapter 0612, Appendix E, Examples of Minor Issues, dated November 1, 2023.

Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix F, Fire Protection and Post - Fire Safe Shutdown SDP. The finding was assessed a low degradation rating because it represented a hole in the wall or floor with an area less than a single five-inch diameter penetration seal and therefore screened as Green.

Cross-Cutting Aspect: H.5 - Work Management: The organization implements a process of planning, controlling, and executing work activities such that nuclear safety is the overriding priority. The work process includes the identification and management of risk commensurate to the work and the need for coordination with different groups or job activities. Specifically, the planning for Work Order 124867684 did not involve the fire protection group. If Fire Protection had been involved, it is reasonable to assume that they would have identified the impact on the CO2 boundary and the work would have been performed using the appropriate fire protection controls thereby maintaining CO2 functionality for the Units 1, 2, and 3 standby diesel generators.

Enforcement:

Violation: BFN Unit 1 Operating License Condition 2.C(13), BFN Unit 2 Operating License Condition 2.C(14), and BFN Unit 3 Operating License Condition 2.C(7) states, in part, that the licensee shall implement and maintain in effect all provisions of the approved fire protection program as described in the Fire Protection Report for the facility. Browns Ferry Nuclear Fire Protection Requirements Manual, Revision 26, Section 9.3.11.D, CO2 Systems, states, in part, that CO2 systems for the Unit 1 and 2 diesel generator rooms A, B, C, and D; the Unit 3 diesel generator rooms 3A, 3B, 3C, and 3D; and the Unit 1 & 2 diesel generator auxiliary board room B shall be functional and that the CO2 systems are considered non-functional if penetrations of the enclosure protected by CO2 are breached outside of existing configuration control.

Contrary to the above, between November 1, 2024, and December 16, 2024, the licensee failed to maintain the CO2 systems for the Unit 1 and 2 diesel generator rooms A, B, C, and D; the Unit 3 diesel generator rooms 3A, 3B, 3C, and 3D; and the Unit 1 & 2 diesel generator auxiliary board room B functional. Specifically, the licensee failed to utilize the existing configuration control program to breach CO2 system enclosures in each of these nine rooms.

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

Assessment 71152S Semi Annual Trend in Procurement Document Control The inspectors performed interviews and plant walkdowns and sampled a population of condition reports during the during a roughly one-year period ending on December 31, 2024. Based upon the samples reviewed, the inspectors had a concern with the quality of purchase orders. For example, the inspectors identified that the licensee received new station battery cells that were factory tested to the correct standard but the wrong year because the year was not specified in the purchase order. While reviewing procurement documents for the high pressure coolant injection rupture discs, the inspectors identified concerns with the licensee's oversight of commercial grade dedication activities by their supplier. Lastly, the inspectors identified gaps with the procurement of safety related services for the platinum coating of main steam relief valve pilot disc seats.

The inspectors resolved the technical issues in each of these cases to ensure that the identified concerns did not constitute a technical concern for the ability of the associated equipment to perform their intended functions; however, each issue represented an unnecessary challenge to the proper control of safety related procurement. When reviewed in aggregate, these issues represented a trend in behaviors that might lead to more significant issues in the future. The inspectors determined that the licensee had and continued to take actions to address the identified issues and the behaviors that contributed to the trends. The inspectors did not identify any findings as a result of this inspection.

Main Steam Relief Valves Lift Settings Outside of Technical Specification Required Setpoints Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NCV 05000296/2024004-02 Open/Closed Not Applicable 71153 A self-revealed Severity Level IV NCV of Technical Specification (TS) 3.4.3 and TS 3.0.4 was identified when the licensee discovered, through as found test results, that four of thirteen Main Steam Relief Valves (MSRVs) that were removed for testing had as found lift settings outside of the +/-3 percent setpoint band required for their operability.

Description:

The Browns Ferry Unit 3 TS 3.4.3 requires twelve of the thirteen MSRVs to be operable while in Modes 1, 2, and 3. On May 7, 2024, the licensee was notified of as-found testing results that four MSRVs from Unit 3 were outside of the +/-3 percent setpoint band required for operability per surveillance requirement 3.4.3.1. It was determined that MSRV BFN-3-PCV-001-0005 and BFN-3-PCV-001-0022 failed due to corrosion bonding to the valve seat and simmering. MSRV BFN-3-PCV-001-0004 and BFN-3-PCV-001-0030 failed due to a relaxation of the setpoint spring over time. All MSRVs were considered to be inoperable during the entire operating cycle from April 3, 2022, to February 17, 2024, and longer than permitted by TS 3.4.3. Additionally, TS 3.0.4 requires that when a limiting condition for operation (LCO) is not met, entry into an applicable Mode or specified condition is not permitted unless the associated actions permit continued operation. On April 3, 2022, BFN Unit 3 entered a TS 3.4.3 Applicable Mode when LCO TS 3.4.3 Required Actions were not met.

The affected valves remained capable of maintaining reactor pressure below the ASME code limit of 1375 psig. All thirteen of the MSRV pilot valves were replaced during the Unit 3 Spring 2022 refueling outage. The previous corrective action from LER 05000260/2021-002-00 to apply a platinum coating to the pilot using the plasma enhanced magnetron sputtering deposition method (PEMS), which improves the quality and adhesion of the coating, has been utilized. A flaking issue has been noted with the platinum coated pilot disc. The Boiling Water Reactor Owners' Group (BWROG) is currently working toward a solution to improve the quality and adhesion of the platinum coating on the discs.

Corrective Actions: The licensee replaced all thirteen MSRV pilot valves during the spring 2024 (U3R21) refueling outage. As left testing verified that these refurbished pilot valves were within +/- 1 percent of their setpoints. The installed valves have implemented corrective actions from past occurrences of corrosion bonding that include preparing the pilot discs in accordance with the revised procedure and vendor recommendations. The currently installed refurbished valves had platinum coatings applied utilizing the PEMS deposition method, and as-left values were verified to be within +/- 1 percent of their setpoints. Additional corrective actions may be developed based on feedback from the Boiling Water Reactor Owners Group related to corrosion bonding of this specific model safety relief valve.

Corrective Action References: CRs 962223, 1286467, 1410577, 1521190, 1658693, 1699286, 1775232, 1822254, 1860559, and 1929514.

Performance Assessment:

The NRC determined this violation was not reasonably foreseeable and preventable by the licensee and therefore is not a performance deficiency.

Enforcement:

The ROPs significance determination process does not specifically consider the regulatory process impact in its assessment of licensee performance. Therefore, it is necessary to address this violation which impedes the NRCs ability to regulate using traditional enforcement to adequately deter non-compliance.

Severity: This violation is characterized as a Severity Level (SL) IV violation based on its similarity to SL IV example 6.1.d.1 in the Enforcement Policy. The inspectors also reviewed NRC Enforcement Policy, Section 2.2.1, "Factors Affecting Assessment of Violations", which states, in part, that in determining the appropriate enforcement response to a violation, the NRC considers, whenever possible, risk information in assessing the safety or security significance of violations and assigning severity levels. The inspectors determined the issue to be of very low safety significance because the valves remained capable of performing their required safety function.

Violation: Browns Ferry Nuclear Unit 3 Technical Specification 3.4.3, "Safety/Relief Valves (S/RVs)," Condition A, requires that with one or more required S/RVs inoperable, that the unit be in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

Contrary to the above, four required S/RVs were inoperable from April 3, 2022, to February 17, 2024, and the unit did not enter Mode 3 and Mode 4 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />, respectively.

Browns Ferry Nuclear Unit 3 Technical Specification LCO 3.0.4, requires, in part, that when an LCO is not met, entry into a mode or other specified condition in the applicability shall only be made when the associated actions to be entered permit continued operation in the mode or other specified condition in the applicability for an unlimited period of time.

Contrary to the above, on April 3, 2022, Unit 3 entered a Technical Specification 3.4.3 applicable mode when Technical Specification LCO 3.4.3 required actions were not met.

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

EXIT MEETINGS AND DEBRIEFS

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

• On January 14, 2025, the inspectors presented the integrated inspection results to Daniel Komm, Site Vice President, and other members of the licensee staff.

DOCUMENTS REVIEWED

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

Corrective Action

Documents

1979883

Engineering

Changes

ECP BFN-20-

1150

Information Technology Upgrades

71111.05

Work Orders

24867684

71111.12

Miscellaneous

R40-240229-549

Maintenance Rule 14th Periodic Report

03/10/2024

Corrective Action

Documents

CR 1962832,

1540236,

1965693,

1965792,

1963793,

1963794,

1965828,

1968863,

1971949,

1977118,

283660

71111.15

Miscellaneous

Purchase Order

28645

Add platinum to main steam relief valve pilot discs

Corrective Action

Documents

CR 1892408,

1892410,

1848830

0-47W462-3

Mechanical Standby Liquid Control System

Drawings

1-47E-856-2

Flow Diagram Demineralized Water

Engineering

Changes

BFN-23-029-01

SLC Separation Modification

71111.18

Work Orders

24048762

Corrective Action

Documents

1963793,

1973522

71111.24

Work Orders

24871621,

23526028,

23485047,

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

24963499

Corrective Action

Documents

CR 1929158,

1936239,

1936470,

1963793,

1963794,

1965828,

1962832,

1540236,

1965620,

1769257,

1892410,

1908551,

1902569,

1892408,

1891412,

1912158,

1911843

Miscellaneous

Purchase Order

7683053

Procedures

0-TI-360

Containment Leak Rate Program

71152A

Work Orders

24871621,

24313418,

23827281,

24342380