IR 05000346/2024003
| ML24318A723 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 11/14/2024 |
| From: | Dariusz Szwarc NRC/RGN-III/DORS/RPB2 |
| To: | Tony Brown Vistra Operations Company |
| References | |
| IR 2024003 | |
| Download: ML24318A723 (1) | |
Text
SUBJECT:
DAVIS-BESSE NUCLEAR POWER STATION - INTEGRATED INSPECTION REPORT 05000346/2024003
Dear Terry Brown:
On September 30, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Davis-Besse Nuclear Power Station. On October 8, 2024, the NRC inspectors discussed the results of this inspection with you and other members of your staff. The results of this inspection are documented in the enclosed report.
Two findings of very low safety significance (Green) are documented in this report. Two of these findings involved violations of NRC requirements. 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 III; the Director, Office of Enforcement; and the NRC Resident Inspector at Davis-Besse Nuclear Power Station.
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 III; and the NRC Resident Inspector at Davis-Besse Nuclear Power Station.
November 14, 2024 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, Dariusz Szwarc, Chief Reactor Projects Branch 2 Division of Operating Reactor Safety Docket No. 05000346 License No. NPF-3
Enclosure:
As stated
Inspection Report
Docket Number:
05000346
License Number:
Report Number:
Enterprise Identifier:
I2024003-0058
Licensee:
Vistra Operations Company LLC
Facility:
Davis-Besse Nuclear Power Station
Location:
Oak Harbor, OH
Inspection Dates:
July 01, 2024, to September 30, 2024
Inspectors:
R. Cassara, Resident Inspector
B. Towne, Senior Resident Inspector
Approved By:
Dariusz Szwarc, Branch 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.
List of Findings and Violations
Inadequate Assessment of Fire Brigade Performance During an Unannounced Fire Drill Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000346/202400301 Open/Closed
[P.6] - Self-Assessment 71111.05 The inspectors identified a finding of very low safety significance and associated non-cited violation (NCV) of the Renewed Facility Operating License NPF3, Condition 2.C(4),
Fire Protection when the licensee failed to identify a hazard during an unannounced fire brigade drill. Specifically, a miscommunication during the drill led to fire brigade members taking actions that, in a real scenario, could have endangered fire brigade members. The drill controllers did not identify the hazard to the fire brigade during the conduct of the drill and failed to note it as a weakness or deficiency during the drill debrief.
Reactor Protection System Flow Modules Found Not Conforming to Design for Multiple Channels and Ready-Spares Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green NCV 05000346/202400302 Open/Closed
[P.2] -
Evaluation 71152 A A self-revealed Green finding and an associated non-cited violation (NCV) of 10 CFR Part 50,
Appendix B, Criterion XV, Nonconforming Materials, Parts, or Components, was identified when the licensee failed to identify the installation of non-conforming parts in a safety-related system. Specifically, the licensee failed to identify reactor coolant system (RCS) flow modules that did not conform to design specifications prior to installation into Channels 1 and 2 of the reactor protection system (RPS). The nonconformance of the RCS flow modules resulted in an increase in circuit noise that caused three spurious trip signals of RPS Channel 1 within a 5-week period.
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
71111.01 - Adverse Weather Protection
Impending Severe Weather Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated readiness for thunderstorms and high winds during the week ending August 31, 2024.
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) High pressure injection system train 1 during normal at power operation on July 16, 2024
- (2) Motor-driven auxiliary feedwater (AFW) pump while AFW system train 2 is inoperable on July 28, 2024
- (3) Component cooling water system during the monthly run of emergency diesel generator (EDG) 1 on August 15, 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) No. 3 mechanical penetration room, rooms 303 and 303PC elevation 585', fire area PFP-AB303 on July 18, 2024
- (2) Condensate storage tank area, room 345, fire area II, elevations 585', 603', and 623' on July 28, 2024
- (3) AFW pump 1 room, fire area E, elevation 565', 1PFP-AB237 on August 6, 2024
- (4) Emergency core cooling system pump room 11, room 105, fire area AB01, elevation 555' and 545', fire area 1PFP-AB105 on August 12, 2024
- (5) No. 4 mechanical penetration room, rooms 115C, 314, and 314CC, fire area A during the week ending August 31, 2024
Fire Brigade Drill Performance Sample (IP Section 03.02) (2 Samples)
- (1) The inspectors evaluated fire brigade training and performance during a simulated fire in X01 startup transformer, elevation 585', on August 16, 2024.
- (2) The inspectors evaluated fire brigade training and performance during a simulated fire in X01 startup transformer, elevation 585', on September 13, 2024.
71111.06 - Flood Protection Measures
Flooding Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated internal flooding mitigation protections in the circulating water pump room 585', during the week ending August 9, 2024.
71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated an emergency response organization full-scale drill simulating a fuel handling accident and radiological release followed by multiple dropped rods and RCS leakage into containment resulting in a general emergency declaration on August 14, 2024.
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 (SSCs) remain capable of performing their intended function:
- (1) Station blackout diesel generator radiator maintenance during the week ending July 27, 2024
- (2) AFW pump 2 target rock flow control valve repairs during the week ending August 3, 2024
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (6 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) Elevated risk during at power containment entry to add oil to reactor coolant pump (RCP) 21 during the week ending July 20, 2024
- (2) Elevated risk during the return to service of RPS channel 1 from bypass for the performance of surveillances on other RPS channels during the week ending July 20, 2024
- (3) Elevated risk during key work activity execution of RCP inputs to steam feed rupture control system (SFRCS) and RPS channel 3 functional test; C1 bus undervoltage relay functional test on August 14, 2024
- (4) Elevated risk during scheduled work activities on anticipatory reactor trip system (ARTS) channel 3 and RCP monitor to channel 1 SFRCS and channel 1 RPS on September 3, 2024
- (5) Elevated risk during a scheduled maintenance outage of EDG 1 during the week of September 13, 2024
- (6) Elevated risk during maintenance on AFW pump train 2 during the week ending September 21, 2024
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (6 Samples)
The inspectors evaluated the licensees justifications and actions associated with the following operability determinations and functionality assessments:
- (1) RPS channel 1 due to spurious trip on Flux/Delta Flux/Flow bistable on July 2, 2024
- (2) Train 2 of AFW due to AFW pump discharge flow controller failing to meet acceptance criteria for minimum asfound voltage during the performance of DBSP03161, AFW Train 2 Level Control, Interlock, and Flow Transmitter Test on July 28, 2024
- (3) Safety features actuation system channel 1 after data light found off during the week ending July 13, 2024
- (4) Containment air cooler 1 service water return inboard vacuum breaker due to leakage from telltale drain during testing on August 16, 2024
- (5) Subcooling margin meter due to display anomalies during the week ending September 14, 2024
- (6) AFW pump 2 due to post-maintenance test performed with suspect data during the week ending September 21, 2024
71111.18 - Plant Modifications
Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02) (3 Samples)
The inspectors evaluated the following temporary or permanent modifications:
- (1) Auxiliary boiler full flow test line installation during the week ending August 9, 2024
- (2) Repair of buried cast iron fire protection piping with ductile iron piping with installation of cathodic protection during the week ending August 16, 2024
- (3) Modification for EDG 2 to replace power packs assembly with new design during the week ending September 13, 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) (8 Samples)
- (1) Post-maintenance test of MU59C seal return isolation logic after replacement of auxiliary contactor BE1177 during the week ending July 13, 2024
- (2) Post-maintenance test of safety features actuation system channel 1 after failed auxiliary contactor replaced during the week ending July 13, 2024
- (3) Post-maintenance test of station air compressor 2 after scheduled maintenance during the week ending July 27, 2024
- (4) Post-maintenance test of station blackout diesel generator after radiator maintenance during the week ending July 27, 2024
- (5) Post-maintenance test and return to operability of AFW train 2:
DBSP03161 - AFW Train 2 Level Control, Interlock, and Flow Transmitter Test, following calibration of AF6451 AFW Pump 12 Discharge Control Valve on July 29, 2024
- (6) Post-maintenance test of EDG 1 following scheduled maintenance outage and powerpack replacement on September 11, 2024
- (7) Post-maintenance test of AFW pump 2 after scheduled maintenance during the week ending September 21, 2024
- (8) Post-maintenance test of EDG 2 after scheduled maintenance during the week ending September 28, 2024
Surveillance Testing (IP Section 03.01) (4 Samples)
- (1) DBME03045, C1 Bus Under Voltage Unit Functional Test, on August 14, 2024
- (2) RPS channel 4 overpower, power/imbalance/flow, and power/pumps trip function calibration on August 27, 2024
- (3) EDG 2 monthly test on August 29, 2024
- (4) Containment spray train 1 quarterly pump and valve test on September 6, 2024
Inservice Testing (IST) (IP Section 03.01) (2 Samples)
- (1) DBSP03151, Auxiliary Feedwater Pump 1 Quarterly Test, on August 8, 2024
- (2) Inservice testing of service water pump 3 during the week ending August 31, 2024
Diverse and Flexible Coping Strategies (FLEX) Testing (IP Section 03.02) (1 Sample)
- (1) FLEX equipment spent fuel pool spray and pump, and alternate low pressure flex emergency feedwater pump during the week ending July 13, 2024
71114.06 - Drill Evaluation
Additional Drill and/or Training Evolution (1 Sample)
The inspectors evaluated:
- (1) Emergency response organization full-scale drill simulating a fuel handling accident and radiological release followed by multiple dropped rods and RCS leakage into containment resulting in a general emergency declaration on August 14,
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) July 1, 2023, through June 30, 2024 IE03: Unplanned Power Changes per 7000 Critical Hours Sample (IP Section 02.02) (1 Sample)
- (1) July 1, 2023, through June 30, 2024
IE04: Unplanned Scrams with Complications (USwC) Sample (IP Section 02.03) (1 Sample)
- (1) July 1, 2023, through June 30, 2024
MS05: Safety System Functional Failures (SSFFs) Sample (IP Section 02.04) (1 Sample)
- (1) July 1, 2023, through June 30, 2024
MS06: Emergency AC Power Systems (IP Section 02.05) (1 Sample)
- (1) October 1, 2023, through June 30, 2024
MS07: High Pressure Injection Systems (IP Section 02.06) (1 Sample)
- (1) October 1, 2023, through June 30, 2024
MS08: Heat Removal Systems (IP Section 02.07) (1 Sample)
- (1) October 1, 2023, through June 30, 2024
MS09: Residual Heat Removal Systems (IP Section 02.08) (1 Sample)
- (1) October 1, 2023, through June 30, 2024
MS10: Cooling Water Support Systems (IP Section 02.09) (1 Sample)
- (1) October 1, 2023, through June 30, 2024 BI01: Reactor Coolant System (RCS) Specific Activity Sample (IP Section 02.10) (1 Sample)
- (1) July 1, 2023, through June 30, 2024
BI02: RCS Leak Rate Sample (IP Section 02.11) (1 Sample)
- (1) October 1, 2023, through June 30, 2024
71152 A - 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) Incorrect Capacitors Found Installed in FYRC1A1 and FYRC1B1 for RPS Channel 1, CR202406404
- Inspectors dispositioned this issue as a violation of 10CFR Part 50, Appendix B, Criterion XV Non-conforming Materials, Parts, or Components.
See the results section of the report for additional detail.
- (2) Excessive transient combustibles observed by inspectors in the Condensate Storage Tank Room - CR202406145
- Inspectors dispositioned this issue as a minor performance deficiency. See the results section of the report for additional detail.
71152 S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02)
- (1) The inspectors reviewed the corrective action program for trends in work order processing errors that might be indicative of a more significant safety issue.
A review of condition reports (CRs) for 2024 revealed that 15 CRs have been written to address work order processing errors. Some work orders are missing/lost, and some CRs describe other work management processing errors including missing cybersecurity reviews, missed clearance writing milestones, and overdue order review.
71153 - Follow-Up of Events and Notices of Enforcement Discretion Event Report (IP Section 03.02) (1 Partial)
The inspectors evaluated the following licensees event reporting determinations to ensure it complied with reporting requirements.
(1)
(Partial)
The inspectors reviewed aspects of Licensee Event Report (LER) 2021001, Emergency Diesel Generator Speed Switch Failure due to Direct Current System Ground, (ADAMS Accession Number ML21105A489). This review was insufficient to close the LER. The results of this inspection should be considered during subsequent reviews and closure of the LER. This LER remains open.
INSPECTION RESULTS
Inadequate Assessment of Fire Brigade Performance During an Unannounced Fire Drill Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000346/202400301 Open/Closed
[P.6] - Self-Assessment 71111.05 The inspectors identified a finding of very low safety significance and associated non-cited violation (NCV) of the Renewed Facility Operating License NPF3, Condition 2.C(4), Fire Protection when the licensee failed to identify a hazard during an unannounced fire brigade drill. Specifically, a miscommunication during the drill led to fire brigade members taking actions that, in a real scenario, could have endangered fire brigade members. The drill controllers did not identify the hazard to the fire brigade during the conduct of the drill and failed to note it as a weakness or deficiency during the drill debrief.
Description:
On August 16, 2024, the inspectors observed an unannounced fire drill involving a simulated fire in the 01 startup transformer located in the area to the north of the turbine building.
The fire brigade responded as expected, and a hose team simulated the snaking out of an adjacent fire hose to fight the fire. A communication over the radio that the transformer was deenergized was passed, and the hose team simulated application of water to the transformer. It was revealed during the drill debrief that the control room operators had simulated shifting downstream loads to the opposite transformer and deenergized the transformer auxiliaries but had not simulated isolating the transformer from the switchyard.
Control room operators must coordinate with grid operators to open the switchyard breakers, which was not simulated during the drill. This condition would have left the transformer energized with 345kV to all three phases, creating a risk of injury when the hose team applied water to the transformer. The firefighting strategy for the fire scenario did not include coordination with switchyard operators, which would be necessary to fully deenergize the startup transformer and prevent a hazardous condition. Although this condition was recognized by the licensee staff, they did not consider that as a hazard that could impact the firefighting activities. Following the drill debrief, the controllers graded the drill performance with a passing score of 96/100. The inspectors raised a concern about the missed hazard to the fire marshal and operations management, and the matter was entered into the licensees corrective action program on August 22, 2024.
Corrective Actions: A condition report was entered into the licensees corrective action program on August 22, 2024. The firefighting strategy for a fire in the startup transformer was adjusted to ensure that control room operators would coordinate with switchyard operators to open the appropriate breakers and fully deenergize the transformer prior to application of water by the hose team. On September 13, 2024, an unannounced drill was observed by inspectors with the same scenario which was conducted with a different fire brigade team to ensure that the hazardous condition was not repeated.
Corrective Action References: CR202406745
Performance Assessment:
Performance Deficiency: The inspectors determined that the licensees failure to identify a hazard to the fire brigade members and its potential impact to the firefighting activities during the drill debrief was a performance deficiency within their ability to foresee and prevent.
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.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power.
The issue screened to Green because the inspectors answered Yes to the question in Exhibit 2, Section D.1.a - Fire Brigade and concluded that the finding would not have significantly affected the ability of the fire brigade to respond to the fire.
Cross-Cutting Aspect: P.6 - Self-Assessment: The organization routinely conducts self-critical and objective assessments of its programs and practices. This finding has a cross-cutting aspect in the area of Problem Identification and Resolution, Self-Assessment, because Davis-Besse did not conduct a self-critical or objective assessment of fire brigade drill performance. Specifically, during the drill debrief, the licensee staff did not consider a hazardous condition existed when firewater was applied to energized transformer.
Enforcement:
Violation: Davis-Besse Facility Operating License Condition 2.C.(4), Fire Protection, requires the licensee to implement and maintain in effect all provisions of the approved fire protection program that comply with 10 CFR 50.48(a) and 10 CFR 50.48(c).
Per the licensees Updated Final Safety Analysis Report Section 9.5.1, the licensees fire protection program is described in NGDB00302, DBNPS Fire Protection Program.
The Fire Hazard Analysis Report (FHAR), which is part of the overall program, describes the analysis that ensures compliance with 10 CFR 50.48(c). Table B1 Section 3.4.3(c)of the FHAR states, in part that, Fire brigade drills assess the fire brigades ability to respond to, control, and extinguish fires...Each fire drill is critiqued, and strengths and weaknesses are identified. Contrary to the above, on August 16, 2024, the licensee failed to identify a weakness in fire brigade performance. Specifically, the fire brigade post-drill evaluation failed to identify a hazard that, had simulated events been real, could have resulted in the injury of fire brigade members and potentially delayed firefighting activities.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Reactor Protection System Flow Modules Found Not Conforming to Design for Multiple Channels and Ready-Spares Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green NCV 05000346/202400302 Open/Closed
[P.2] -
Evaluation 71152 A A self-revealed Green finding and an associated non-cited violation (NCV) of 10 CFR Part 50, Appendix B, Criterion XV, Nonconforming Materials, Parts, or Components, was identified when the licensee failed to identify the installation of non-conforming parts in a safety-related system. Specifically, the licensee failed to identify reactor coolant system (RCS) flow modules that did not conform to design specifications prior to installation into Channels 1 and 2 of the reactor protection system (RPS). The nonconformance of the RCS flow modules resulted in an increase in circuit noise that caused three spurious trip signals of RPS Channel 1 within a 5-week period.
Description:
On June 26, 2024, during normal full-power operation, the RPS Channel 1 experienced a spurious trip on Flux-Delta Flux-Flow. RPS Channel 1 was taken to Bypass in accordance with Technical Specifications. Troubleshooting revealed that a small flow perturbation on the RCS Loop 1 coincided with a normal neutron flux spike to generate a trip signal in RPS Channel 1. The protection circuit signal filtering which normally minimizes fluctuations in RCS flow signal indicated decreased dampening on Channel 1 compared to the other RPS Channels. RPS Channel 1 experienced two additional trip signals on July 2, and July 21, 2024, from the same condition. On August 07, 2024, the licensee conducted a review of the instock available spare Foxboro modules for RPS Channel 1 RCS flow circuit.
The inspection revealed that the RCS flow modules had an improper capacitor configuration that was not in accordance with design. Specifically, a single capacitor for signal dampening/filtering was installed in place of two capacitors. Further investigation of the extent of this condition revealed that a similar nonconformance was present in the RCS Flow modules that were currently installed in RPS Channel 1 and 2. The licensee determined that the capacitor configuration of the non-conforming RCS flow modules was subject to a reduced amount of signal dampening that contributed to the circuit noise that caused the trip signals in RPS Channel 1.
A similar issue with RPS Channel 1 RCS flow modules occurred on November 28, 2023.
The station installed RCS flow modules into RPS Channel 1 with incorrect capacitor settings due to using the wrong vendor technical manual. The issue was dispositioned as a Green NCV in inspection report 05000346/2024001 (ADAMS Accession Number ML24122C664).
The extent of condition following the event failed to identify the non-conforming RCS Flow modules in either the ready-spare inventory or installed in RPS Channel 1 and 2.
Corrective Actions: The licensee conducted maintenance to return the instock available spare RCS flow modules to the design configuration. They subsequently swapped and reconfigured the RCS flow modules in RPS Channel 1 and 2 to restore the design configuration. RPS Channel 1 was returned to service following a monitoring period that revealed no additional spurious trip signals.
Corrective Action References: CR202406404; work order (WO) 200955236
Performance Assessment:
Performance Deficiency: The failure to identify the presence of the non-conforming RCS flow modules as ready-spares and their installation into RPS Channels 1 and 2 is a performance deficiency within the licensees ability to foresee and prevent.
Screening: The inspectors determined the performance deficiency was more-than-minor because it was associated with the Design Control attribute of the Initiating Events cornerstone and adversely affected the cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Specifically, the installation of non-conforming RCS flow modules into the RPS resulted in several spurious reactor trip signals. Multiple RPS Channels and the ready-spares were affected, which reduced the reliability of the associated safety-related equipment and increased the likelihood of a spurious reactor trip.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power.
The issue screened as Green because the inspectors answered No to the question in Exhibit 1, Section B - Transient Initiators.
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. This finding had a cross-cutting aspect in the area of Problem Identification and Resolution, Evaluation, because Davis-Besse did not thoroughly evaluate the extent of condition following a similar issue with RCS flow modules in RPS Channel 1 in November 2023. Specifically, on November 28, 2023, the station installed RCS flow modules into RPS Channel 1 with incorrect capacitor settings due to using the wrong vendor technical manual. The extent of condition prescribed following that event failed to identify non-conforming RCS flow modules in either the ready-spare inventory or installed in RPS Channel 1 and 2.
Enforcement:
Violation: Title 10 of CFR 50, Appendix B, Criterion XV, Nonconforming Materials, Parts, or Components, requires, in part, that measures shall be established to control components which do not conform to requirements in order to prevent their inadvertent use or installation.
Contrary to the above, from November 28, 2023, to August 7, 2024, the licensee failed to establish measures to control components which did not conform to requirements in order to prevent their inadvertent use or installation. Specifically, the licensee failed to identify non-conforming instock spare RCS flow modules and failed to prevent their installation in RPS Channels 1 and 2, contributing to several spurious reactor trip signals.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Minor Performance Deficiency 71152 A Excessive Transient Combustibles Observed by Inspectors in the Condensate Storage Tank Room Minor Performance Deficiency: During performance of a fire area walkdown in the condensate storage tank (CST) room on July 29, 2024, the inspectors observed an excessive amount of transient combustibles. The licensee wrote condition report, CR202406145 and performed an evaluation of the transient combustibles found in the room against the allowable loading. The transient combustible evaluation found that the estimated fire loading for the transient combustibles was within the allowable value for the fire area. The licensee removed the excess transient combustibles from the CST room.
Davis-Besse procedure DBFP00007, Control of Transient Combustibles, sections 6.1.5 and 6.1.6, describe the following requirements for transient combustibles: The quantity of transient combustibles within the work areas shall be limited to that quantity required to perform the work scope during the shift. All waste, debris, scrap, rags, oil spills, or other combustibles resulting from work activity shall be removed following completion of the work activity, or at the end of each work shift, whichever is sooner. Material can remain in work areas where work will be continued for multiple shifts, days, etc., provided waste material is properly disposed of regularly and if necessary, a transient combustible permit has been obtained. Contrary to the guidance contained in DBFP00007, the CST room contained excess transient combustible material that was not associated with a work activity and did not have a transient combustible permit.
Screening: The inspectors determined the performance deficiency was minor. The failure to adhere to the requirements of DBFP00007 is a performance deficiency that is within the ability of the licensee to foresee and prevent. The issue screens as minor because the total amount of transient combustibles found within the CST room were within the allowable fire loading of the compartment.
Even though the value of the transient combustibles were less than the allowed fire loading of the compartment, the storage of transient combustibles in risk-significant locations may indicate a lack of awareness for fire hazards within the power block, which have been established in the sites probabilistic risk analysis as a major contributor to overall site risk.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On October 8, 2024, 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
NORM-LP7221
Davis-Besse Flooding Mitigating Strategy Assessment
Support Document
RAEP02810
Tornado or High Winds
RAEP02810
Tornado or High Winds
Procedures
RAEP02830
Flooding
DBOP06011
High Pressure Injection System
Procedures
DBOP06262
Component Cooling Water System Procedure
Corrective Action
Documents
Resulting from
Inspection
2406857
NRC Identified Fire Barrier Question
08/27/2024
CFP013.06028
Four AFW Pump Room Ventilation Openings in Fire Barriers
ECCS Pump Room 101 Room 105
Auxiliary Feed Pump 1 Room, Room 237, Fire Area E
No. 3 Mechanical Penetration Room Rooms 303 and 303PC
No. 4 mechanical Penetration Room, Fire Area A
Fire Plans
Risk Significant Area
DBFP00005
Fire Brigade
Procedures
Condensate Storage Tank Area, Room 345, Fire Area II
Miscellaneous
EP Drill Exercise Guide
N/A
2405002
SBODG Low Radiator Air Flow Readings
Corrective Action
Documents
2406143
AF6451 AUX FD PMP12 DISCH CONTROL VALVE Close
mVdc Does Not Meet the Min Value Spec
200888402
AUX FD PMP 12 DISCH CONTROL SOLENOID
10/04/2023
200889827
AFW Train 2 Level Control, Interlock and Flow Transmitter
Test
07/28/2024
200954639
Failed PMT
07/28/2024
Work Orders
200954640
AFW Train 2 Level Control, Interlock, and Flow Transmitter
Test
07/29/2024
Corrective Action
Documents
2405748
Computer Point L828 RCP 21 Motor Lower Bearing Oil
Level Coming in Low and Clearing
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Miscellaneous
ODMI 24.05
Operation with RPS Channel 1 in Manual Bypass
DBMI03205
Channel Functional Test/Calibration and Response Time of
RCP Monitor (RC3601) to SFRCS LCH 1 and RPS CH1
DBMI03358
Anticipatory Reactor Trip System (ARTS) Channel 3
Interchannel Logic Test for Mode 1
DBBP-OPS0011
Protected Equipment Posting
NOP-ER3004
Procedures
NOP-OP1007
Risk Management
Work Orders
200951337
RCP 21 Motor Lower Bearing Oil Level Low
07/17/2024
2405590
RPS CH1 Flux/DFlux/Flow Bistable Tripped with Channel in
Manual Bypass
07/02/2024
2405777
MU59 C9 RCP 101 Seal Return Isolation SFAS Data Light
Extinguished
07/11/2024
2406143
AFW PMP 12 DISCH CONTROL VALVE Does Not Meet
the Reqd Min Volts
07/28/2024
2406638
Leakage Past Service Water Vacuum Breaker SW76
08/16/2024
2407085
CTRM PAM Panel CH2 Subcooling Margin Meter Display
Anomalies
09/05/2024
2407188
CRTM CH2 Subcooling Margin Meter Further Degradation
09/10/2024
2407381
AFP 2 Quarterly Test Data is Suspect
09/18/2024
Corrective Action
Documents
2407441
AFW 2 Discharge Pressure Inaccurate
09/20/2024
DBPF03020
Service Water Train 1 Valve Test
Procedures
DBSP03161
AFW TRAIN 2 Level Control Interlock, and Flow Transmitter
Test
200889827
AFW Train 2 Level Control Interlock and Flow Transmitter
Test
07/28/2024
200951398
Reactor Coolant Pump 11 Seal Return Isolation Indication
Repair
07/11/2024
200951398
Reactor Coolant Pump 11 Seal Return Iso
07/11/2024
200954640
AFW Train 2 Level Control, Interlock, and Flow Transmitter
Test
07/29/2024
Work Orders
200957120
RCS Margin to SAT Indicator (TSAT) Post Accident
Monitoring System
09/11/2024
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Engineering
Changes
ECP170329-001
Installation of Auxiliary Boiler Test Line
Miscellaneous
231084
Design Equivalent Change Package - Replace Power Packs
Assembly with New Design
DBSS04126
Auxiliary Boiler Quarterly Low Level, Low-Low Level, and
Trip Test
EC241078-001
Update M0601 KEE Pipe Class
NOP-ER3001
Problem Solving and Decision Making
Procedures
NOP-ER300103
Simple Troubleshooting Plant
Work Orders
200946386
Aux Boiler Weld Inspection
06/10/2024
2405002
SBODG Low Radiator Air Flow Readings
2405777
MU59C (RCP 11 Seal Return Isolation) SFAS Data Light
Extinguished
2405777
MU59C SFAS Date Light Extinguished
07/11/2024
Corrective Action
Documents
2407451
Excessive Service Water Pump
DBME03045
C1 Bus Under Voltage Unit Functional Test
DBSC03071
Emergency Diesel Generator Monthly Test
DBSC03076
Emergency Diesel Generator 1 184 Day Test
DBSC04271
SBODG Monthly Test
DBSP03151
AFP 1 Quarterly Test
DBSP03160
AFP 2 Quarterly Test
DBSP03161
AFW Train 2 Level Control, Interlock, and
Flow Transmitter Test
Procedures
DBSP03337
Containment Spray Train 1 Quarterly Pump and Valve Test
200834960
Perform AFP 1 Quarterly Test
08/06/2024
200853103
4000 Hour Maintenance Main 8000 Hour Maintenance
07/21/2024
200878559
Station Air Compressor Maintenance
07/22/2024
200884994
RT 12196 DBFX-P1A Flow Performance Test
08/07/2024
200885301
RPS Channel 4 Functional Calibration
08/27/2024
200888798
RT 12206 DBFX-P3P Flow Performance Test
07/08/2024
200889801
SBODG Monthly Test - Critical Periodic Test
07/24/2024
200891381
08/29/2024
Work Orders
200892770
AFP 2 Quarterly Test
09/16/2024
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
200897991
EDG 2 184 Day Test
09/25/2024
200951398
Reactor Coolant Pump 11 Seal Return ISO
07/11/2024
200951398
RSP 11 Seal Return Isolation Valve
07/11/2024
200958413
PMT EDG 2 Overspeed Trip Test
09/25/2024
2406145
Transient Combustibles in the CST Room
07/28/2024
71152 A A
Corrective Action
Documents
2406404
Incorrect Capacitors Found Installed in FYRC1A1 and
FYRC1B1 for RPS Channel 1
08/07/2024
71152 S
Corrective Action
Documents
2407198
Trend CR for Work Order Closure Issues
09/10/2024