IR 05000346/2025001
| ML25128A008 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 05/09/2025 |
| From: | Sanchez-Santiago E NRC/RGN-III/DORS/RPB2 |
| To: | Tony Brown Vistra Operations Company |
| References | |
| IR 2025001 | |
| Download: ML25128A008 (1) | |
Text
SUBJECT:
DAVIS-BESSE NUCLEAR POWER STATION-INTEGRATED INSPECTION REPORT 05000346/2025001
Dear Terry Brown:
On March 31, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Davis-Besse Nuclear Power Station. On April 10, 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.
No NRC-identified or self-revealing findings were identified during this inspection.
A licensee-identified violation which was determined to be of very low safety significance is documented in this report. We are treating this violation as a non-cited violation (NCV)
consistent with Section 2.3.2 of the Enforcement Policy.
If you contest the violation or the significance or severity of the violation documented in this inspection report, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region III; the Director, Office of Enforcement; and the NRC Resident Inspector at Davis-Besse Nuclear Power Station.
May 9, 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, Elba M. Sanchez Santiago, Chief Reactor Projects Branch 2 Division of Operating Reactor Safety Docket No. 05000346 License No. License No. NPF-3
Enclosure:
As stated
Inspection Report
Docket Number:
05000346
License Number:
Report Number:
Enterprise Identifier:
I2025001-0062
Licensee:
Vistra Operations Company, LLC
Facility:
Davis-Besse Nuclear Power Station
Location:
Oak Harbor, OH
Inspection Dates:
January 01, 2025 to March 31, 2025
Inspectors:
R. Cassara, Resident Inspector
B. Towne, Senior Resident Inspector
Approved By:
Elba M. Sanchez Santiago, Chief
Reactor 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 Davis-Besse Nuclear Power Station, in accordance with the Reactor Oversight Process. The Reactor Oversight Process is the NRCs program for overseeing the safe operation of commercial nuclear power reactors. Refer to https://www.nrc.gov/reactors/operating/oversight.html for more information. A licensee-identified non-cited violation is documented in report section: 71111.11Q.
List of Findings and Violations
No findings or violations of more than minor significance were identified.
Additional Tracking Items
None.
PLANT STATUS
Davis-Besse operated at or near rated thermal power 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) (3 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
- (1) Auxiliary feedwater train 2 during quarterly test of auxiliar feedwater pump 1 on January 24, 2025
- (2) Decay heat/low pressure injection train 1 while train 1 is the protected train during the week ending February 15, 2025
- (3) Component cooling water (CCW) train 1 while shifting CCW in service train to train 2 on March 19, 2025
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) Emergency core cooling system (ECCS) pump room train 1, fire area AB01 on January 8, 2025
- (2) Condensate storage tank room 345, fire area II on January 13, 2025
- (3) Control room emergency ventilation system (CREVS) equipment room 603 and 603A, fire area HH on January 30, 2025
- (4) Service water pipe tunnel, room 250, fire area BG, during the week ending March 1, 2025
- (5) Emergency diesel generator (EDG) 2 room, rooms 319 and 318A, fire area J on March 26, 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) (2 Samples)
- (1) The inspectors observed and evaluated licensed operator performance in the control room as they performed a down power to 99.5 percent and took actions to place the integrated controller system in manual to swap feedwater inlet temperature instruments on February 27, 2025
- (2) The inspectors observed and evaluated licensed operator performance in the control room during a down power to 95 percent for control rod exercise test, main turbine stop valve testing, main turbine control valve testing, and main turbine combined intermediate valve testing on March 14, 2025
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated licensed operator performance in the simulator and classroom during licensed operator training on February 20, 2025
71111.12 - Maintenance Effectiveness
Maintenance Effectiveness (IP Section 03.01) (2 Samples)
The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components remain capable of performing their intended function:
- (1) Maintenance rule (a)(1) evaluation for the auxiliary boiler following engineering modification and maintenance outage during the week of February 17, 2025
- (2) Maintenance rule evaluation of the EDG air compressor 3 due to tripping on overload and not shutting off a setpoint, lifting the air reservoir on March 11, 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) Assessment of elevated risk and mitigating actions due to extreme cold weather alert during the week ending January 11, 2025
- (2) Assessment of elevated risk and mitigating actions due to maintenance on high pressure injections (HPI) train 1 minimum flow recirculating stop check valve on March 25, 2025
- (3) Inspection of mitigating fire risk actions as prescribed by the fire hazards analysis report (FHAR) due to EDG 2 room fire detection out of service during the week ending March 28, 2025
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (5 Samples)
The inspectors evaluated the licensees justifications and actions associated with the following operability determinations and functionality assessments:
- (1) Operability determination of safety features actuation system (SFAS) channel 1 due to sequencer failure during SFAS functional test on January 22, 2025
- (2) Operability determination of control room envelope and CREVS train 1 due to air inleakage above the limit for acceptance criteria on January 30, 2025
- (3) Operability determination of feedwater inlet temperature due to temperature channel divergence during the week ending March 1, 2025
- (4) Operability determination of makeup pumps due to makeup pump room AC failure with temperatures approaching the limit for operability on March 10, 2025
- (5) Operability determination of core flood tank 1 level instrumentation due to diverging trend in level between channels, during the week ending March 29, 2025
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) CREVS access door seal modification during the week ending February 8, 2025
- (2) Emergency feedwater new battery and charger system during the week ending March 8, 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) (7 Samples)
- (1) EDG 1 following work on the air start system on January 2, 2025
- (2) Station blackout diesel generator after maintenance on air start compressor during the week ending January 11, 2025
- (3) SFAS channel 1 after replacement of sequencer during the week ending January 25, 2025
- (4) PMT of the control room emergency ventilation system following temporary modification of the access door downstream of the charcoal filter to correct air inleakge on February 1, 2025
- (5) PMT of HP32 HPI train 1 minimum flow recirculating stop check valve following diagnostic static testing on March 25, 2025
- (6) PMT of MU6421 alternate reactor coolant system makeup isolation valve following motor-operated valve (MOV) breaker replacement on March 20, 2025
- (7) PMT of diesel fire pump following scheduled maintenance and overspeed limiting device replacement during the week ending March 8, 2025
Surveillance Testing (IP Section 03.01) (4 Samples)
- (1) Auxiliary feedwater pump 1 quarterly test on January 24, 2025
- (2) Offsite dose calculation manual license condition requirement for storm sewer flow rate calculation/estimation due to failed flow rate instrument, on February 20, 2025
- (3) Calibration of the seismic monitoring system during the week ending March 1, 2025
- (4) Station air compressor 1 after scheduled maintenance during the week ending January 25, 2025
Inservice Testing (IST) (IP Section 03.01) (1 Sample)
- (1) Auxiliary feed pump train 2 inservice testing during the week ending March 8, 2025
Diverse and Flexible Coping Strategies (FLEX) Testing (IP Section 03.02) (1 Sample)
- (1) Turbo Marine FLEX diesel generators during the week ending February 8,
OTHER ACTIVITIES-BASELINE
71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02)
- (1) The inspectors reviewed the corrective action program for trends in measuring and test equipment (M&TE) readiness that might be indicative of a more significant safety issue. Inspectors identified a trend of documented instances of M&TE not being available for scheduled surveillances, was out of calibration, or was not in stock and equivalent equipment had to be identified. The inspectors reviewed associated documents to ensure there weren't any delayed, missed, or improperly performed surveillance on safety systems as a result of this trend. The adverse trend was communicated to the licensee and entered into the corrective action program. No issue of significance was identified.
INSPECTION RESULTS
Licensee-Identified Non-Cited Violation 71111.11Q This violation of very low safety significance was identified by the licensee and has been entered into the licensee corrective action program and is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Violation: Technical Specification Section 5.4.1.a requires, in part, that written procedures shall be established, implemented, and maintained covering the applicable procedures recommended in Regulatory Guide 1.33, Revision 2, Appendix A, February 1978.
NRC Regulatory Guide 1.33, Revision 2, Appendix A, Section 7 addresses Procedures for Control of Radioactivity (For limiting materials released to environment and limiting personnel exposure) and Section 7.e, addresses Radiation Protection Procedures.
The licensee established procedure NOP-OP4301, "Respiratory Protection Program,
" Rev. 10, October 20, 2017, to address, in part, the program requirements for respiratory protection at all licensee facilities against all industrial hazards, including those that may be radioactive, in accordance with 10CFR20 and 29CFR1910.134. Procedure NOP-OP4301, Rev. 10, Step 4.1.6.1 states: Department and contractor supervision shall ensure compliance of all applicable respirator procedures for employees working under their direction. Step 4.1.6.6 requires the licensee to: Maintain emergency respirator qualification, when required, for employees working under their direction. This includes ensuring that employees who may be required to don emergency respirators maintain respirator glasses, if applicable, and are clean-shaven. Step 4.6.7.3 requires: Active NRC-licensed personnel who have a corrective lens requirement as a license condition shall maintain appropriate corrective lenses readily available for emergency respirator use.
Contrary to the above, from October 2, 2023 to January 16, 2025, the licensee failed to implement procedures as required by TS 5.4.1.a. Specifically, the licensee failed to implement steps 4.1.6.1, 4.1.6.6, and 4.6.7.3 of procedure NOP-OP4301 when facility managers/supervisors failed to ensure compliance of all applicable respirator procedures for employees working under their direction and failed to ensure that the licensed operator properly maintained a set of respirator glasses. The licensed operator, who had a corrective lens requirement as a license condition, failed to properly maintain the appropriate corrective lenses readily available for emergency respirator use.
Significance/Severity: Green. The inspectors assessed the significance of the finding using IMC 0609 Appendix C, Occupational Radiation Safety Significance Determination Process.
The inspectors determined that the finding is not related to ALARA, does not involve an overexposure, does not have a substantial potential for overexposure, did not compromise the licensee's ability to assess dose, and therefore screens to Green, or very low safety significance.
Corrective Action References: CR202500314 Licensed Individual Did Not Have Personal Spectacle Kit Available in the CTRM
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On April 10, 2025, the inspectors presented the integrated inspection results to T. Brown, Site Vice President, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
DBOP06012
Decay Heat and Low Pressure Injection System Operating
Procedure
DBOP06233
Auxiliary Feedwater System
Procedures
DBOP06262
Component Cooling Water System Procedure
ECCS Pump Room 11, Fire Area AB01
Diesel Generator 12 Room, Rooms 319 and 318A, Fire
Area J
AC Equipment Room and Records and Storage, Room 603
and 603A, Fire Area HH
Service Water Pipe Tunnel, Room 250, Fire Area BG
Fire Plans
Condensate Storage Tank Area, Room 345, Fire Area II
Corrective Action
Documents
CR202501772
Unexpected Alarm While Testing Main Turbine Combined
Intercept Valves
03/14/2025
DBSC03272
Control Rod Exercising Test
DBSC04150
Main Turbine Stop Valve Test
DBSC04152
Main Turbine Combined Intermediate Valve Test
DBSc004151
Main Turbine Control Valve Test
Procedures
OPS-GOP-S102
Simulator Guide
CR202408778
SV3915 Aux Boiler Atomizing Steam Inlet Solenoid Valve
Plumbed Incorrectly
11/08/2024
CR202408830
Failed Relay During Commissioning Testing
11/10/2024
CR202409051
Spurious Trip During Commissioning
11/19/2024
CR202409384
Aux Boiler Failed to Fire
2/06/2024
CR202501604
EDG Compressor 3 Overload
03/09/2025
Corrective Action
Documents
CR202501650
EDG AC 3 (C113) Running Continuously
03/10/2025
Procedures
NOP-ER3004
Corrective Action
Documents
Resulting from
Inspection
CR202502149
Documentation of NRC Resident Question
03/26/2025
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Miscellaneous
FHAR
Davis-Besse Nuclear Power Station Unit 1 Fire Hazards
Analysis Report
CR202408828
Small Change Seen in Feedwater Temperature Trending
11/10/2024
CR202408996
Diverging Trent in CFT 1 Level Indicators
11/16/202
CR202500451
Did Not Receive All Expected Computer Points While
Testing SFAS CH 1 Sequence
01/02/2025
Cr202500624
Control Room Unfiltered Leakage Greater than Acceptance
Criteria
01/30/2025
Corrective Action
Documents
CR202501564
Makeup Pump Room AC Unit Not Blowing Air
03/07/2025
Work Orders
200967888
Core Flood Tank 11 Level Transmitter Buffer Replacement
2/26/2025
Miscellaneous
251016-001
Design Equivalent Change Package
ECP210112-001
Replace EFWP Engine Start Battery Charger
08/07/2023
Procedures
ECP210113-001
Replace EFWP Engine Start Battery
07/18/2023
DBFP04047
Diesel Fire Pump Tes
DBFP04049
Diesel Fire Pump Tests
DBOP06412
Process and Area Radiation Monitor
DBPF03272
Post-Maintenance Valve Test
DBSC03070
Emergency Diesel Generator 1 Monthly Test
DBSC03110
SFAS Channel 1 Functional Test
DBSP03151
AFP 1 Quarterly Test
DBSP03160
AFP2 Quarterly Test
Procedures
DBSS03301
Control Room Unfiltered Air Inleakage Test for Control
Room Emergency Ventilation
200735037
Station Blackout Diesel Generator Air Start Post
Maintenance Test
01/08/2025
200834963
AF05 Pressure Test
03/18/2025
200834964
AF07 Pressure Test
03/18/2025
200834965
AF08 Pressure Test
03/18/2025
200871152
Station Air Compressor 1 Maintenance
01/28/2025
200885668
Seismic Monitoring System Test
2/27/2025
200891520
FXK1P Functional Test
2/11/2025
Work Orders
200891521
FXK1A Functional Test
2/11/2025
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
200892861
PMT of HP32 HPI Train 1 MIN Flow Recirc Stop Check
Valve
03/25/2025
200900042
Perform EDG 1 Monthly Test
01/02/2025
200900907
SFAS Channel 1 Functional Test
01/22/2025
200911500
PMT MU6421 ARCS Makeup Isolation Valve MOV BRKR
Replacement
03/20/2025
200962090
Perform Quarterly Test on Aux Feedwater Pump 1
01/24/2025
200965529
CH 1 Sequence Module Replacement
01/22/2025
CR202409338
Rollup CR for Unavailability of Measuring & Test Equipment
2/03/2024
Corrective Action
Documents
CR202500637
DB Maintenance 1H25 IPA - New Gap - Unavailability of
Measuring & Test Equipment
01/30/2025