IR 05000390/2024004
| ML25043A055 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 02/13/2025 |
| From: | Louis Mckown NRC/RGN-II/DORS |
| To: | Erb D Tennessee Valley Authority |
| References | |
| EAF-RII-2025-0052 IR 2024004 | |
| Download: ML25043A055 (1) | |
Text
SUBJECT:
WATTS BAR NUCLEAR PLANT - INTEGRATED INSPECTION REPORT 05000390/2024004 AND 05000391/2024004 AND APPARENT VIOLATION
Dear Delson Erb:
On December 31, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Watts Bar Nuclear Plant. On February 3, 2025, the NRC inspectors discussed the results of this inspection with Christopher Reneau, Site Vice President, and other members of your staff. The results of this inspection are documented in the enclosed report.
Section 71111.12 of the enclosed report discusses a finding with an associated apparent violation for which the NRC has not yet reached a preliminary significance determination. The performance deficiency is the failure to identify the failure mechanism of emergency diesel generator (EDG) damper failures as required by quality-related procedure NPG-SPP-22.300, Corrective Action Program. Multiple damper failures occurred during calendar year 2024 where the failure mechanism was not identified, and thus not corrected, which led to the 2A-A EDG being declared inoperable on November 8, 2024.
We are currently evaluating the significance of this finding and will notify you in a separate correspondence once we have completed our preliminary significance review. We ask that you promptly provide any relevant information that you would like us to consider in making our determination. You will be given an additional opportunity to provide additional information prior to our final significance determination unless our review concludes that the finding has very low safety significance (i.e., Green). The NRCs significance determination process is designed to encourage an open dialogue between your staff and the NRC; however, neither the dialogue nor the written information you provide should affect the timeliness of our final determination.
Licensee-identified violations which were determined to be of very low safety significance are documented in this report. We are treating these violations as non-cited violations consistent with Section 2.3.2 of the Enforcement Policy.
February 13, 2025 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 Watts Bar 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 Watts Bar Nuclear Plant.
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. 05000390 and 05000391 License Nos. NPF-90 and NPF-96
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000390 and 05000391
License Numbers:
Report Numbers:
05000390/2024004 and 05000391/2024004
Enterprise Identifier:
I-2024-004-0029
Licensee:
Tennessee Valley Authority
Facility:
Watts Bar Nuclear Plant
Location:
Spring City, Tennessee
Inspection Dates:
October 1, 2024 to December 31, 2024
Inspectors:
S. Battenfield, Operations Engineer
P. Cooper, Senior Reactor Inspector
D. Hardage, Senior Resident Inspector
A. Nielsen, Branch Chief
D. Restrepo, Health Physicist
J. Rivera, Health Physicist
D. Strickland, Senior Reactor Inspector
J. Walker, Senior Emergency Preparedness Inspector
R. Wehrmann, 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 Watts Bar 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. Licensee-identified non-cited violations are documented in report sections: 71111.18 and 71124.0
List of Findings and Violations
Failure to Identify a Failure Mechanism for Inlet Dampers not Opening Challenged 2A-A EDG Operability Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Pending AV 05000390,05000391/2024004-01 Open EAF-RII-2025-0052
[P.2] -
Evaluation 71111.12 NRC inspectors identified a finding with its safety significance as 'yet to be determined' and associated apparent violation (AV) of 10 CFR 50, Appendix B, Criterion V, Instructions,
Procedures, and Drawings, for the licensee's failure to identify the failure mechanism affecting performance of emergency diesel generator (EDG) intake damper sections as required by quality-related procedure NPG-SPP-22.300, "Corrective Action Program."
Specifically, the licensee's performance of the same corrective actions subsequent to repetitive failures across a variety of the same components reasonably indicated that the equipment or part failure mechanism of multiple damper sections was not identified, which is required by NPG-SPP-22.300, Revision 25. This resulted in the 2A-A EDG being declared inoperable due to the failure of multiple damper sections on November 8, 2024.
Additional Tracking Items
None.
PLANT STATUS
Unit 1 began the inspection period at rated thermal power (RTP). Unit 1 commenced end of life coastdown operations on October 20, 2024. On November 1, 2024, the plant was shut down from 95 percent RTP for refueling outage 1R19. Reactor startup after refueling was performed on December 8, 2024. The unit returned to RTP on December 11, 2024, and remained at or near RTP for the remainder of the inspection period.
Unit 2 operated at or near RTP for the entire 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 onsite portions of IPs. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.
REACTOR SAFETY
71111.04 - Equipment Alignment
Partial Walkdown Sample (IP Section 03.01) (1 Sample)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
- (1) Unit 1 'A' train residual heat removal (RHR) with the train in operation, in Mode 5 with loops filled, and 'B' train secured for testing on November 3, 2024
Complete Walkdown Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated system configurations during a complete walkdown of the Unit 1 'A' train safety injection system on November 26, 2024, through November 30, 2024.
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (5 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 480V transformer rooms and 480V electric board rooms on October 9, 2024
- (2) Unit 1 auxiliary building, elevation 713, in the vicinity of motor-driven auxiliary feedwater pumps and component cooling system (CCS) pumps on October 22, 2024
- (3) Unit 1 upper containment on November 30, 2024
- (4) Unit 1 annulus on December 1, 2024
- (5) Unit 1 lower containment on December 2, 2024
===71111.08P - Inservice Inspection Activities (PWR) The inspector verified that the reactor coolant system (RCS) boundary, reactor vessel internals, risk-significant piping system boundaries, and containment boundary are appropriately monitored for degradation and that repairs and replacements were appropriately fabricated, examined and accepted by reviewing the following activities in Unit 1 during refueling outage 19 from November 11 - November 14, 2024:
PWR Inservice Inspection Activities Sample - Nondestructive Examination and Welding Activities (IP Section 03.01)===
The inspectors verified that the following nondestructive examination and welding activities were performed appropriately:
- (1) Ultrasonic Examination
- RCS-002, pipe - elbow, ASME Class 1
- RCS-003, elbow - pipe, ASME Class 1
- RCS-004, pipe - elbow to pipe, ASME Class 1
- WP-06, pressurizer longitudinal shell weld, Class 1
- WP-01, pressurizer lower head to shell weld, Class 1
Visual Examination
- RVWASHER-01 to 54, Closure Head Bolting, Class 1
- RVNUT-01 to 54, Closure Head Bolting, Class 1 Welding Activities
- WO# 122805538, Replace 1-FSV-068-0394, -0396, -0397
- WO# 117331101, Replace SFP Pump/TBBP Cooler A-A Cooling Coil PWR Inservice Inspection Activities Sample - Vessel Upper Head Penetration Inspection
Activities (IP Section 03.02) (1 Sample)
The inspectors verified that the licensee conducted the following vessel upper head penetration inspections and addressed any identified defects appropriately:
- (1) CRDM Upper Head Penetrations 03, 05, 08,12, 23 PWR Inservice Inspection Activities Sample - Boric Acid Corrosion Control Inspection Activities (IP Section 03.03) (1 Sample)
The inspectors verified the licensee is managing the boric acid corrosion control program through a review of the following evaluations:
- (1) Boric Acid Walkdown - November 13, 2024
- Reviewed engineering evaluations in WO# 121226521 and 124826960
- Reviewed CR's 1970142, 1970052, 1970268, 1970497 PWR Inservice Inspection Activities Sample - Steam Generator Tube Inspection Activities (Section 03.04) (1 Sample)
The inspectors verified that the licensee is monitoring the steam generator tube integrity appropriately through a review of the following examinations:
- (1) Eddy Current Examination
- Steam Generator 1 - Row 89 Column 96
- Steam Generator 2 - Row 100 Column 63
- Steam Generator 3 - Row 97 Column 42
- Steam Generator 4 - Row 94 Column 37
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 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 September 6, 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 control room during reactor shutdown for the refueling outage on November 1, 2024.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated an as found scenario that included a failed power range nuclear instrument, a feedwater leak outside of containment, a loss of offsite power and a faulted steam generator on October 9, 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)2A-A EDG exhaust fan intake damper failure on November 8, 2024
Quality Control (IP Section 03.02) (1 Sample)
The inspectors evaluated the effectiveness of maintenance and quality control activities to ensure the following SSC remains capable of performing its intended function:
(1)1B-B centrifugal charging pump rotating element replacement under WO 124556162 on November 20 through November 25, 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:
===123621442
- (2) Unit 1/Unit 2 elevated risk due to control room habitability barrier breaches for cable pulls on October 30, 2024, under WOs 123428819 and 123428818
- (3) Unit 1 yellow shutdown risk for RCS drain down on November 4 through November 5, 2024
- (4) Unit 2 elevated risk due to emergent loss of 'H-B' essential raw cooling water (ERCW)pump and 'D' common station service transformer (CSST) on November 16, 2024
- (5) Unit 1 transition from Mode 5 to Mode 1 during the week of December 7 through December 13, 2024
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01)===
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
- (1) Condition Report (CR) 1974606, main control room chiller 'B' found tripped on high discharge pressure
71111.18 - Plant Modifications
Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02) (2 Samples)
The inspectors evaluated the following temporary or permanent modifications:
(1)50.59 screen associated with change to technical requirements manual, sections 3.0.7 and 3.6.3 following the 2C lower compartment cooler (LCC) failure on November 12, 2024 (2)procedurally controlled temporary modification to install dehumidifiers in Unit 1 upper containment
71111.20 - Refueling and Other Outage Activities
Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated Unit 1 refueling outage 1R19 activities from October 31 to December 9, 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 (IP Section 03.01) (7 Samples)
(1)auxiliary control air compressor 'A' air and ERCW piping testing on October 9, 2024, under WOs 121323946 and 121323947 (2)2A CCS pump seal replacement on October 16, 2024, under WO 123621442 (3)1A-A main control room air handling unit motor replacement on October 17, 2024, under WO 124878337 (4)main steam safety valve testing and setpoint adjustment on October 29, 2024, under WO 123489743 (5)1A-A diesel generator output breaker relay AX replacement on October 31, 2024, under WO 124926709 (6)1A-A main control room chiller oil pump overload heater replacement on November 5, 2024, under WO 124374289 and 124931377
124958780 Surveillance Testing (IP Section 03.01)
(1)station blackout testing of the 1B-B EDG, on November 25, 2024, under WO
124931587 (2)1-SI-62-907, "Chemical Volume Control System Valve Position Indication and Full Stroke Exercise," on November 26, 2024, under WO 123764077 Inservice Testing (IP Section 03.01)
- (1) RHR full flow test on November 4 through November 6, 2024, under WO 123763791
Containment Isolation Valve Testing (IP Section 03.01) (1 Sample)
(1)local leak rate test on Unit 1 penetration X-106 on November 14, 2024
Ice Condenser Testing (IP Section 03.01) (1 Sample)
(1)lower inlet door testing per 1-SI-61-5 on December 1, 2024, under WO 123764072
71114.02 - Alert and Notification System Testing
Inspection Review (IP Section 02.01-02.04) (1 Sample)
- (1) The inspectors evaluated the maintenance and testing of the alert and notification system during the week of October 7, 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 Response Organization during the week of October 7, 2024.
71114.04 - Emergency Action Level and Emergency Plan Changes
Inspection Review (IP Section 02.01-02.03) (1 Sample)
- (1) The inspectors evaluated submitted Emergency Action Level, Emergency Plan, and Emergency Plan Implementing Procedure changes during the week of October 7, 2024. 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 during the week of October 7,
RADIATION SAFETY
71124.01 - Radiological Hazard Assessment and Exposure Controls
Radiological Hazard Assessment (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated how the licensee identifies the magnitude and extent of radiation levels and the concentrations and quantities of radioactive materials and how the licensee assesses radiological hazards.
Instructions to Workers (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated how the licensee instructs workers on plant-related radiological hazards and the radiation protection requirements intended to protect workers from those hazards.
Contamination and Radioactive Material Control (IP Section 03.03) (2 Samples)
The inspectors observed/evaluated the following licensee processes for monitoring and controlling contamination and radioactive material:
(1)observed workers and tools exiting the radiologically controlled area (2)observed workers and tools exiting Unit 1 lower containment during the U1R19 refueling outage
Radiological Hazards Control and Work Coverage (IP Section 03.04) (3 Samples)
The inspectors evaluated the licensee's control of radiological hazards for the following radiological work:
- (1) Unit 1 reactor head lift activities
- (2) Unit 1 upper internals lift activities
- (3) Unit 1 scaffolding activities High Radiation Area and Very High Radiation Area Controls (IP Section 03.05) (5 Samples)
The inspectors evaluated licensee controls of the following high radiation areas and very high radiation areas:
- (1) Unit 1 RHR and containment spray heat exchanger room (2)tritiated drain collector tank room (3)waste packaging area
- (4) Unit 1 mixed bed and cation valve gallery (5)spent resin storage tank area Radiation Worker Performance and Radiation Protection Technician Proficiency (IP Section 03.06) (1 Sample)
- (1) The inspectors evaluated radiation worker and radiation protection technician performance as it pertains to radiation protection requirements.
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)
"foxtrot pad" outside storage area (2)dry active waste (DAW) storage building (3)refueling floor
Radioactive Waste System Walkdown (IP Section 03.02) (3 Samples)
The inspectors walked down the following accessible portions of the solid radioactive waste systems and evaluated system configuration and functionality:
(1)liquid waste processing system in packaging area (2)liquid waste collection tanks in the auxiliary building (3)spent resin and filter storage container, associated piping, and valve components in railroad bay
Waste Characterization and Classification (IP Section 03.03) (2 Samples)
The inspectors evaluated the following characterization and classification of radioactive waste: (1)2023 DAW (2)2024 chemical and volume control resin
Shipping Records (IP Section 03.05) (4 Samples)
The inspectors evaluated the following non-excepted radioactive material shipments through a record review:
- (1) WBN-22-04, Low specific activity (LSA), Resin
- (2) WBN-24-03, LSA, Filters
- (3) WBN-23-03, Type B, Resin
- (4) WBN-24-04, Type B, Resin
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 2023 through September 2024)
- (2) Unit 2 (October 2023 through September 2024)
IE03: Unplanned Power Changes per 7000 Critical Hours Sample (IP Section 02.02) (2 Samples)
- (1) Unit 1 (October 2023 through September 2024)
- (2) Unit 2 (October 2023 through September 2024)
IE04: Unplanned Scrams with Complications Sample (IP Section 02.03) (2 Samples)
- (1) Unit 1 (October 2023 through September 2024)
- (2) Unit 2 (October 2023 through September 2024)
MS05: Safety System Functional Failures Sample (IP Section 02.04) (2 Samples)
- (1) Unit 1 (October 2023 through September 2024)
- (2) Unit 2 (October 2023 through September 2024)
OR01: Occupational Exposure Control Effectiveness Sample (IP Section 02.15) (1 Sample)
- (1) May 20, 2023, through November 8, 2024 PR01: Radiological Effluent Technical Specifications/Offsite Dose Calculation Manual Radiological Effluent Occurrences Radiological Effluent Occurrences Sample (IP Section 02.16) (1 Sample)
- (1) August 5, 2023, through November 8, 2024
EP01: Drill/Exercise Performance Sample (IP Section 02.12) (1 Sample)
- (1) April 1, 2023, through June 30, 2024 EP02: Emergency Response Organization Drill Participation (IP Section 02.13) (1 Sample)
- (1) April 1, 2023, through June 30, 2024
EP03: Alert And Notification System Reliability Sample (IP Section 02.14) (1 Sample)
- (1) Apr 1, 2023, through June 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) Inspectors performed a follow-up on the 2023 third quarter integrated inspection report (IR 2023003, ADAMS ML23313A002) non-cited violation (05000390,05000391/2023003-01) for failure to maintain records of activities affecting quality.
71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02)
- (1) For the period of June to December 2024, the inspectors reviewed the licensees corrective action program, which included inspector-identified issues, for potential adverse trends in the implementation of the Watts Bar fire protection program that might be indicative of a more significant safety issue.
INSPECTION RESULTS
Failure to Identify a Failure Mechanism for Inlet Dampers not Opening Challenged 2A-A EDG Operability Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Pending AV 05000390,05000391/2024004-01 Open EAF-RII-2025-0052
[P.2] -
Evaluation 71111.12 NRC inspectors identified a finding with its safety significance as 'yet to be determined' and associated apparent violation (AV) of 10 CFR 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, for the licensee's failure to identify the failure mechanism affecting performance of emergency diesel generator (EDG) intake damper sections as required by quality-related procedure NPG-SPP-22.300, "Corrective Action Program."
Specifically, the licensee's performance of the same corrective actions subsequent to repetitive failures across a variety of the same components reasonably indicated that the equipment or part failure mechanism of multiple damper sections was not identified, which is required by NPG-SPP-22.300, Revision 25. This resulted in the 2A-A EDG being declared inoperable due to the failure of multiple damper sections on November 8, 2024.
Description:
On November 8, 2024, while performing rounds on the 2A-A EDG, an operator discovered three inlet damper sections, 2-MTR-30-444A-A, 2-MTR-30-444B-A, and 2-MTR-30-444D-A, had failed to open with an exhaust fan for the 2A-A EDG running.
Each EDG has four inlet damper sections, and at least two damper sections are required to be open to support EDG operability in accordance with licensee procedures. The basis of this procedural requirement is licensee calculation EPMAMP081789. Appendix E, Section 9.0, Conclusion, states in part, failure of three of the four dampers causes the pressure loss to exceed the capability of the fan, causing possible unstable fan operation and exceeding the motor allowable horsepower during a LOOP.
Based on the above, the operators declared the 2A-A EDG inoperable on November 8, 2024, at 0715. The licensee entered this issue into the corrective action program as CR 1971401 and generated a minor maintenance work order to repair the damper sections.
A review of the licensee's corrective action program revealed that additional EDG damper failures had occurred in the 2024 calendar year:
The 2A-A EDG experienced the following damper failures:
1. March 13, 2024 (CR 1916514), when two sections failed to open, closed to WO
2. May 15, 2024 (CR 1931587), when one section failed to open, closed to WO
3. August 14, 2024 (CR 1950860), when one section failed to open, closed to WO
4. October 17, 2024 (CR 1966168), when two sections failed to open, closed to WO
The 2B-B EDG experienced the following damper failures:
1. June 10, 2024 (CR 1936490), one section failed to open, closed to WO
2. September 18, 2024 (no CR identified), one damper failed to open
3. October 23, 2024 (CR 1967644), two sections failed to open, and a third section was
not fully open, closed to WO The 1B-B EDG experienced the following damper failures:
1. October 8, 2024 (CR 1964560), one damper section failed to open, closed to WO
The defined work scope in each of these minor maintenance work orders was to:
Troubleshoot damper intake linkage (for the appropriate fan) and lubricate pivot points and linkages as required to correct issue. These work orders lubricated pivot linkage points on each damper intake and stroked each damper several times. Revision 25 of NPG-SPP-22.300, Corrective Action Program, became effective on June 27, 2024, and added a requirement that cause evaluations identify the failure mechanism. Specifically, NPG-SPP-22.300, Section 3.4.2, "Corrective Action Development," paragraph B.1 prescribes, that licensee staff create at least one action to correct the adverse condition, which includes an action to address the equipment or part failure mechanism. The CRs for the damper failures noted after June 27, 2024, occurred between August 14 and November 8, 2024, and did not identify the equipment or part failure mechanism.
Corrective Actions: On November 8, 2024, at 18:06, the 2A-A EDG was declared operable after repair and testing of damper sections 2-MTR-30-444B-A and 2-MTR-30-444D-A. The licensee documented issues related to the EDG dampers in the corrective action program, including trend reviews of damper failures (CR 1967949 and CR 1971736) and damper failure analysis (CR 1966168).
Corrective Action References: CR 1971736, CR 1967949, CR 1966168
Performance Assessment:
Performance Deficiency: The licensees failure to identify the failure mechanism affecting performance of EDG intake damper sections as required by quality-related procedure NPG-SPP-22.300 is a performance deficiency. Specifically, multiple damper failures occurred over a one-year period where the failure mechanism of the dampers was not identified and corrected. This directly resulted in the 2A-A EDG being declared inoperable.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Equipment Performance 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. The damper failures degraded the ability of the EDG HVAC system to provide adequate intake air flow to the EDG room, which challenged the reliability of the associated EDG. This led to the licensee declaring the 2A-A EDG inoperable on November 8, 2024.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. Using Exhibit 2, Mitigating Systems Screening Questions, Section A, Mitigating SSCs and PRA Functionality (except Reactivity Control Systems), questions 3 & 6 were answered as "Yes,"
therefore, a Detailed Risk Evaluation is required.
Cross-Cutting Aspect: P.2 - Evaluation: The organization thoroughly evaluates issues to ensure that resolutions address causes and extent of conditions commensurate with their safety significance. Following multiple damper failures, the licensee performed corrective actions that restored short-term functionality. However, the licensee failed to perform a thorough evaluation to identify the failure mechanism as required by NPG-SPP-22.300.
Enforcement:
Violation: 10 CFR 50, Appendix B, Criterion V, requires, in part that, activities affecting quality shall be prescribed by documented instructions, procedures, or drawings, of a type appropriate to the circumstances and shall be accomplished in accordance with these instructions, procedures, or drawings.
Quality-related procedure NPG-SPP-22.300, Revision 25, Section 3.4.2, paragraph B.1 prescribes, for an adverse condition entered in the corrective action program, that licensee staff create at least one action in the action plan to correct the adverse condition, which includes an action that addresses the equipment or part failure mechanism.
Contrary to the above, from August 14 to November 8, 2024, the licensee failed to accomplish activities affecting quality in accordance with an existing procedure appropriate to the circumstances. Specifically, the licensees performance of the same corrective actions subsequent to repetitive failures across a variety of the same components reasonably indicated that these actions were not correcting the identified adverse condition as prescribed by NPG-SPP-22.300. This ultimately resulted in the inoperability of the 2A-A EDG.
Enforcement Action: This violation is being treated as an apparent violation pending a final significance (enforcement) determination.
Licensee-Identified Non-Cited Violation 71111.18 This violation of very low safety significance was identified by the licensee and has been entered into the licensees corrective action program; therefore, it is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Violation: Watts Bar Unit 1 and Unit 2 Technical Specification 5.7.1, "Procedures," Section 1.a., requires, in part that, written procedures shall be established, implemented, and maintained covering the applicable procedures recommended in Appendix A of Regulatory Guide 1.33, Revision 2. Section 6 of Appendix A requires procedures for combating emergencies and other significant events. The licensee established procedure EAP-R-0, Restoration Guidance Emergency Abnormal Operations, Revision 1, in part, to meet the regulatory requirement.
Contrary to the above, until present, the licensee failed to provide procedural direction to restart lower compartment cooler (LCC) fans after a main steam line break (MSLB) accident in EAP-R-0. The accident analysis credits restart of two of the four LCC fans within 1.5 to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> after an MSLB accident to recirculate air in the lower compartment dead-ended spaces. While performing an evaluation following a loss of a Unit 2 LCC, the licensee identified that procedural direction to restart LCCs after an MSLB did not exist.
Significance/Severity: Green. Using Inspection Manual Chapter 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power, Exhibit 2, Mitigating Systems Screening Questions, the inspectors determined that the finding was of very low safety significance (Green) because all questions in Section A, "Mitigating SSCs and PRA Functionality (except Reactivity Control Systems)," were answered No.
Corrective Action References: CR 1971891 Licensee-Identified Non-Cited Violation 71124.08 This violation of very low safety significance was identified by the licensee and has been entered into the licensees corrective action program; therefore, it is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Violation: The NRC regulation in 10 CFR 71.5 requires, in part that, licensees comply with Department of Transportation regulations in 49 CFR 172.200. This regulation requires that all hazardous materials contained in the shipping package be listed on the shipping papers.
Contrary to the above, shipment WBN-23-112 contained batteries and circuit boards that were not listed on the shipping paper. Also, shipment WBN-24-103 contained lead blankets that were not listed on the shipping paper. The issue was identified by site environmental specialists.
Significance/Severity: Green. The correct packaging was used for both shipments, no radiation limits were exceeded, and there was no breach of the packages during transport. Therefore, using the Public Radiation Safety Significance Determination Process, the violation was determined to be of very low safety significance (Green).
Corrective Action References: CR 1960918 Assessment 71152A Follow-up on Failure to Maintain Records of Activities Affecting Quality Inspectors performed a follow-up on the 2023 third quarter integrated inspection report (IR 2023003, ADAMS ML23313A002) non-cited violation (05000390,05000391/2023003-01) for failure to maintain records of activities affecting quality. The scope of this inspection included review of corrective actions taken following the documentation of the non-cited violation in the third quarter 2023 integrated inspection report. The inspectors assessed the corrective actions put into place to correct the previously identified failure to maintain records for work on safety-related SSCs and determined they have been effective based on a reduction in the number of issues identified during this inspection. However, inspectors did identify a minor violation of 10 CFR 50, Appendix B, Criterion VIII, "Identification and Control of Materials, Parts, and Components," which is documented in the results section of this report.
Minor Violation 71152A Failure to Maintain Traceability of Lubricants Used in Safety-Related Applications Minor Violation: Inspectors identified a minor violation of 10 CFR 50, Appendix B, Criterion VIII, "Identification and Control of Materials, Parts, and Components," when the licensee failed to maintain traceability of lubricants used in safety-related applications. Specifically, NRC inspectors identified 35 examples over a one-year period where lubricants were utilized in safety-related components (e.g., RHR pumps, charging pumps, etc.) without documentation traceable to the lubricants end use.
The licensee establishes their self-imposed standards which implement the requirements of 10 CFR 50, Appendix B, Criterion VIII via TVA-NQA-PLN89-A, Nuclear Quality Assurance Plan, Section 8.3, Identification and Control of Materials, Parts and Components, Section 2, Program Element B, Traceability.
Screening: The inspectors determined the performance deficiency was minor. The inspectors screened the performance deficiency in accordance with Inspection Manual Chapter 0612 Appendix B, Issue Screening Questions, and determined the performance deficiency was minor because all questions in Block 4 were answered No.
Enforcement:
The licensee has entered the issue into the corrective action program as CR 1967916. This failure to comply with 10 CFR 50 Appendix B, Criterion VIII, constitutes a minor violation that is not subject to enforcement action in accordance with the NRCs Enforcement Policy.
Assessment 71152S Semiannual Trend Review of Watts Bar Fire Protection Program Implementation The inspectors identified an adverse trend in the licensees control of transient combustible materials as a result of identifying multiple examples over a short period where personnel failed to follow the requirements of procedure NPG-SPP-18.4.7, "Control Transient Combustibles." The inspectors considered it noteworthy that a significant number of the examples were NRC-identified. This issue is documented as a minor violation in the results section of this report.
The inspectors, also, identified an adverse trend in the licensees screening of housekeeping issues as a result of identifying multiple examples over a short period where personnel failed to follow the requirements of procedures NPG-SPP-22.300, "Corrective Action Program," and NPG-SPP-22.302, "Condition Report Screening." The inspectors considered it noteworthy that there were 22 identified misclassifications or closures to the work order process without appropriate controls. Additionally, the Management Review Committee did not identify the misclassification issues or the closure of CRs to work orders without corrective action controls. This issue is documented as a minor violation in the results section of this report.
The inspectors noted that the licensees corrective actions for these items included the immediate correction of the identified discrepancies as well as sharing crew learnings with the site to reinforce the standards associated with transient combustibles and housekeeping practices. The licensee captured these adverse trends within the corrective action program as CR 1989431 and CR 1989437.
Minor Violation 71152S Failure to Control Transient Combustibles Minor Violation: The inspectors identified a minor violation of Watts Bar Unit 1 and Unit 2 Technical Specifications 5.7.1.1d., "Fire Protection Program Implementation," when the licensee failed to control transient combustibles in accordance with procedure NPG-SPP-18.4.7, "Control of Transient Combustibles." NPG-SPP-18.4.7 is a quality-related procedure and requires that the limits for transient combustibles be controlled in accordance with Sections 3.2.1, 3.2.2, 3.3.1, and 3.4. These controls include limiting the transient combustibles to amounts specified based on fire risk and ensuring adequate spacing, establishing separation between transient combustibles and plant equipment, and obtaining a Transient Combustible Permit/Evaluation form with appropriate compensatory measures.
The inspectors identified 15 examples where personnel failed to implement the requirements of NPG-SPP-18.4.7 from June 2024 to December 2024. The inspectors considered it noteworthy that seven of the 15 issues were NRC-identified.
Screening: The inspectors determined the performance deficiency was minor. The inspectors screened the performance deficiency in accordance with Inspection Manual Chapter 0612 Appendix B, Issue Screening Questions, and determined the performance deficiency was minor because all the questions in Block 4 were answered No.
Enforcement:
The licensee has entered the issue into the corrective action program as CR 1989431. This failure to comply with Unit 1 and Unit 2 Technical Specifications 5.7.1.1d.
constitutes a minor violation that is not subject to enforcement action in accordance with the NRCs Enforcement Policy.
Minor Violation 71152S Failure to Properly Screen Housekeeping Issues as Conditions Adverse to Quality Minor Violation: The inspectors identified a minor violation of Watts Bar Unit 1 and Unit 2 Technical Specifications 5.7.1.1d., "Fire Protection Program Implementation," when the licensee failed to control transient combustibles in accordance with procedure NPG-SPP-18.4.7, "Control of Transient Combustibles." NPG-SPP-18.4.7, "Control of Transient Combustibles," credits the implementation of NPG-SPP-01.3, "Housekeeping," to ensure that fire protection requirements are met. The licensee uses the corrective action program screening process as prescribed within procedures NPG-SPP-22.300, "Corrective Action Program," and NPG-SPP-22.302, "Condition Report Screening, to ensure compliance with the fire protection program as established by NPG-SPP-18.4.7 and NPG-SPP-01.3. The inspectors identified 22 examples of fire protection related housekeeping issues that were not entered into the corrective action program from June 2024 through December 2024.
Screening: The inspectors determined the performance deficiency was minor. The inspectors screened the performance deficiency in accordance with Inspection Manual Chapter 0612 Appendix B, Issue Screening Questions, and determined the performance deficiency was minor because all the questions of Block 4 were answered No.
Enforcement:
The licensee has entered the issue into the corrective action program as CR 1989437. This failure to comply with 10 CFR 50, Appendix B, Criterion XVI, Corrective Action, constitutes a minor violation that is not subject to enforcement action in accordance with the NRCs Enforcement Policy.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On October 10, 2024, the inspectors presented the emergency preparedness program inspection results to Christopher Reneau, Site Vice President, and other members of the licensee staff.
- On November 12, 2024, the inspectors presented the radiation protection inspection results to Christopher Reneau and other members of the licensee staff.
- On November 21, 2024, the inspectors presented the inservice inspection results to Christopher Reneau and other members of the licensee staff.
- On February 3, 2025, the inspectors presented the integrated inspection results to Christopher Reneau and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Procedures
1-SOI-74.01
Residual Heat Removal System
Revision 26
Fire Plans
RXN-1-702-01
Reactor Building Elevation 702 prefire plan
Revision 3
Fire Plans
RXN-1-713-01
Reactor Building Elevation 713 prefire plan
Revision 2
Fire Plans
RXN-1-757-01
Reactor Building Elevation 757 prefire plan
Revision 2
Corrective Action
Documents
1970052
Boric Acid Identification on 1-DRV-77-515A
11/03/2024
Corrective Action
Documents
1970142
Wet Mixed Color Boric Acid Leak Downstream of 1-FE-68-
48B
11/03/2024
Corrective Action
Documents
1970268
Dry white/rust Boric Acid Leak on Pipe Cap Downstream of
1-TV-62-614
11/04/2024
Corrective Action
Documents
1970497
Boron Accumulation at 1-I SIV-062-0432 D/L Packing
11/04/2024
Engineering
Evaluations
1970278 WBN-1-
TV-062-0611-S
1-TV-062-0611-S Boric Acid Evaluation
11/18/2024
Engineering
Evaluations
1970451 WBN-1-
TV-077-0504
RCDT Vent Header Test Vent Boric Acid Evaluation
11/21/2024
Miscellaneous
Clearance
Section 1-0140-
GO
1-GO-10 Attachment 30 for Mansell System
11/04/2024
Corrective Action
Documents
Resulting from
Inspection
CR 1978812
NRC questions concerning compensatory manual actions for
'B' main control room chiller
2/11/2024
Operability
Evaluations
CA 1973091-001
Perform past operability evaluation
2/05/2024
Work Orders
Monitoring plan for MCR chiller 'B'
11/23/2024
Corrective Action
Documents
Condition Report
CR 1981667, 1941022
Miscellaneous
A24-0136
Transient Combustible Permit for WO 125041115
Rev 001
Procedures
0-SOI-30.07
Shutdown Board Rooms HVAC el 757 & 772
27
Procedures
0-TI-66.004
Temporary Dehumidifiers in Upper Containment
003
Work Orders
25041115
Ops request to install dehumidifiers in U1 upper IAW 0-TI-
001
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
66.004
Corrective Action
Documents
Resulting from
Inspection
Condition Report
CR 1977690, 1970157, 1976195
Procedures
0-SI-82-4
Loss of Offsite Power with Safety Injection Test - DG 1B-B
Revision 87
Procedures
Monthly Diesel Generator Start and Load Test DG 1A-A
Revision 62
Procedures
1-SI-43-701-A
Containment Isolation Valve Local Leak Rate Test Post
Accident Sampling
Revision 13
Procedures
REP-Appendix C
Watts Bar Nuclear Plant Radiological Emergency Plan
Rev. 116
Corrective Action
Documents
CR 1970822
Corrective Action
Documents
CR 1970865
Procedures
1-SI-63-917
Testing of Cold Leg Accumulator Check Valves
Revision 13
Procedures
NISP-RP-010
Nuclear Industry Standard Process, Radiological Job
Coverage
Revision 2
Radiation
Surveys
WBN-M-
241103-14
Initial entry into Unit 1 cavity
11/03/2024
Radiation
Surveys
WBN-M-
241103-26
U1R19UC Rx Cavity Update / Post Decon
11/03/2024
Radiation
Surveys
WBN-M-
241104-30
R152 U-1 Upper Containment
11/04/2024
Radiation
Surveys
WBN-M-
241105-19
R152 U-1 Upper Containment
11/05/2024
Corrective Action
Documents
CR 1960918
Procedures
NPG-SPP-05.6.1
Radiation Protection Implementation of 10 CFR 37 Category
and Category 2 Quantities of Radioactive Material
Revision 3
Shipping Records
WBN-23-112
11/02/2023
Shipping Records
WBN-24-103
04/09/2024
Corrective Action
Documents
Condition Report
CRs 1872489, 1870666, 1872072, 1887078, 1971528,
1969903, 1968056, 1968054, 1965221, 1962852, 1957122,
1956951, 1956169, 1949850, 1948192, 1948189, 1946290,
Various
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
1937954, 1923258, 1921148, 1920973, 1918142, 1915369,
1911274, 1910212, 1909149, 1908623, 1908276, 1907755,
1904393, 1904326, 1903756, 1896420, 1895140, 1894716,
1893242, 1888958, 1884812, and 1884796
Procedures
0-TI-78
Lubrication Program
23
Corrective Action
Documents
Condition Report
CRs 1975379, 1973584, 1969911, 1969425, 1967055,
1961757, 1961053, 1961048, 1959315, 1957892, 1954732,
1951103, 1945055, 1941609, 1941532, 1978276, 1977965,
1977396, 1977179, 1976127, 1976085, 1971541, 1962922,
1962914, 1961053, 1961048, 1960378, 1959706, 1952812,
1952591, 1952527, 1952506, 1949935, 1948197, 1948196,
1948195, and 1948194
Various