IR 05000395/2025004
| ML26030A039 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 02/03/2026 |
| From: | Matthew Fannon NRC/RGN-II/DORS/PB2 |
| To: | Carr E Dominion Energy South Carolina |
| References | |
| EAF-RII-2026-0008 IR 2025004 | |
| Download: ML26030A039 (0) | |
Text
SUBJECT:
VIRGIL C. SUMMER NUCLEAR PLANT - INTEGRATED INSPECTION REPORT 05000395/2025004 AND APPARENT VIOLATION
Dear Eric S. Carr:
On December 31, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Virgil C. Summer Nuclear Plant. On January 21, 2026, the NRC inspectors discussed the results of this inspection with Beth Jenkins, 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. This finding involved a failure to properly pre-plan and perform maintenance on the turbine-driven emergency feedwater pump governor valve linkage.
We intend to issue our final safety significance determination and enforcement decision, in writing, within 90 days from the date of this letter. The NRCs significance determination process (SDP) 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. We ask that you promptly provide any relevant information that you would like us to consider in making our determination. 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. 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).
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.
February 3, 2026 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 II; the Director, Office of Enforcement; and the NRC Resident Inspector at Virgil C. Summer 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, Matthew S. Fannon, Chief Projects Branch 2 Division of Operating Reactor Safety Docket No. 05000395 License No. NPF-12
Enclosure:
As stated
Inspection Report
Docket Number:
05000395
License Number:
Report Number:
Enterprise Identifier:
I-2025-004-0030
Licensee:
Dominion Energy South Carolina
Facility:
Virgil C. Summer Nuclear Plant
Location:
Jenkinsville, SC
Inspection Dates:
October 1, 2025, to December 31, 2025
Inspectors:
K. Dials, Resident Inspector
M. Donithan, Senior Operations Engineer
B. Griman, Reactor Inspector
M. Read, Senior Resident Inspector
S. Sandal, Senior Reactor Analyst
T. Stephen, Senior Reactor Analyst
Approved By:
Matthew S. Fannon, Chief
Projects Branch 2
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Virgil C. Summer 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. A licensee-identified non-cited violation is documented in report section: 71111.2
List of Findings and Violations
Inadequate Maintenance Strategy Resulting in Inoperability of the Turbine-Driven Emergency Feedwater Pump Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Pending AV 05000395/2025004-01 Open EAF-RII-2026-0008 None (NPP)71111.12 A self-revealed apparent violation (AV) of Technical Specifications (TS) 6.8.1, Procedures and Programs, was identified when the licensee failed to schedule and implement a preventative maintenance procedure appropriate to the circumstances for the governor linkage for the turbine-driven emergency feedwater (TDEFW) pump, which resulted in the inoperability and unplanned unavailability of the pump.
Additional Tracking Items
None.
PLANT STATUS
The unit began the inspection period at rated thermal power. On October 3, 2025, the unit was rapidly downpowered due to a steam leak on a moisture separator drain tank. The unit was returned to rated thermal power on October 13, 2025. On October 14, 2025, the reactor tripped due to a fire on the generator exciter field control breaker. The unit was returned to rated thermal power on October 26, 2025, and remained at or near rated thermal power for the remainder of the inspection period.
INSPECTION SCOPES
Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors performed activities described in IMC 2515, Appendix D, Plant Status, observed risk significant activities, and completed on-site portions of IPs. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.
REACTOR SAFETY
71111.01 - Adverse Weather Protection
Impending Severe Weather Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors validated actions for impending severe weather conditions prior to onset of freezing temperatures on November 10-12, 2025.
71111.04 - Equipment Alignment
Partial Walkdown Sample (IP Section 03.01) (2 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
(1)
'B' train reactor building spray system on October 14, 2025, during 'A' train maintenance
- (2) Residual heat removal system on October 16, 2025, while providing decay heat removal
Complete Walkdown Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated system configurations during a complete walkdown of the vital DC power and safety-related inverters system on October 28, 2025.
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (6 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) Intermediate building elevation 423 feet, fire zone IB11 and fire area IB23.02 on October 1, 2025
- (2) Control room emergency panel in intermediate building elevation 436 feet, fire zones IB-15 and IB-24 on October 28, 2025
- (3) Control building elevation 425 feet, fire zone CB01.02, upper cable spreading room on December 5, 2025
- (4) Control building elevation 448 feet, fire area CB15, upper cable spreading room on December 5, 2025
- (5) Radiological maintenance building on December 12, 2025
- (6) Diesel generator building elevations 427, 436, and 463 feet, on December 18, 2025
Fire Brigade Drill Performance Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated the onsite fire brigade training and performance during an announced fire drill in the service water pump house on October 1, 2025.
71111.07A - Heat Exchanger/Sink Performance
Annual Review (IP Section 03.01) (1 Sample)
The inspectors evaluated readiness and performance of:
(1) 'B' residual heat removal heat exchanger, walkdown completed on October 16, 2025
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 tests 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 tests completed on August 29, 2025, and the biennial written examinations also completed on August 29, 2025.
71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Performance in the Actual Plant/Main Control Room (IP Section 03.01) (1 Sample)
- (1) The inspectors observed and evaluated licensed operator performance in the control room during rapid downpower on October 3, 2025, during startup on October 9, 2025, during a reactor trip on October 14, 2025, and during restart activities on October 23, 2025.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated an operator requalification scenario involving cooldown following steam generator tube rupture on December 17, 2025.
71111.12 - Maintenance Effectiveness
Maintenance Effectiveness (IP Section 03.01) (3 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) Refueling water storage tank concrete pedestal on October 14, 2025
- (2) Control room ventilation and battery room air handling unit dampers on December 29, 2025
- (3) Turbine-driven emergency feedwater pump governor, governor valve, and linkage, inspection completed on December 17, 2025 Per IMC 0309, Reactive Inspection Decision Basis for Power Reactors, the NRC considered whether this inspection sample should be the subject of a reactive inspection and determined that a reactive inspection was not necessary, as documented in ML25323A276.
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) Repairs and commercial grade dedication activities for the turbine-driven emergency feedwater pump on November 16, 2025
Aging Management (IP Section 03.03) (1 Sample)
The inspectors evaluated the effectiveness of the aging management program for the following SSCs that did not meet their inspection or test acceptance criteria:
- (1) Impressed current cathodic protection system for underground diesel fuel oil piping on November 18, 2025
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (1 Sample)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
(1)
'C' main steam safety valve cycling, review completed on December 18, 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) VC-23-00001, 'A' feedwater venturi instrumentation changes, review completed on October 1, 2025
- (2) ECR-50830, Simplex upgrade, review completed on December 15, 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) (6 Samples)
- (1) ERMP-100.011A, FLEX combustion turbine generator testing, on September 24, 2025, following generator protection system setpoint changes, review completed on December 8, 2025
- (2) Turbine-driven emergency feedwater pump on November 16, 2025, following governor and linkage repairs
- (3) Testing XAH0011B, 'B' train air handling unit for emergency feedwater pump ventilation, using MMP-460.025 for filter maintenance and fan testing, on November 19, 2025
- (4) XFN-32B following motor repairs, review completed on December 8, 2025
- (5) STP-395.006, to calibrate feedwater flow transmitter IFT-497, on December 11, 2025
- (6) SOP-102, 'A' Charging Pump testing following room ventilation filter inspection, motor bearing lubrication, and motor oil sampling, on December 29, 2025
Surveillance Testing (IP Section 03.01) (1 Sample)
- (1) STP-125.013A, 'A' emergency diesel generator semi-annual testing, on November 4, 2025
OTHER ACTIVITIES - BASELINE
71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
MS05: Safety System Functional Failures (SSFFs) Sample (IP Section 02.04) (1 Sample)
- (1) Unit 1 (October 1, 2024, through September 30, 2025), review completed December 22, 2025
MS08: Heat Removal Systems (IP Section 02.07) (1 Sample)
- (1) Unit 1 (October 1, 2024, through September 30, 2025), review completed December 22, 2025
MS10: Cooling Water Support Systems (IP Section 02.09) (1 Sample)
- (1) Unit 1 (October 1, 2024, through September 30, 2025), review completed December 22, 2025
71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02) (1 Sample)
- (1) The inspectors reviewed the licensees corrective action program for potential adverse trends regarding fire extinguisher monthly inspections that might be indicative of a more significant safety issue. The review was completed on December 18, 2025.
71153 - Follow-Up of Events and Notices of Enforcement Discretion
Notice of Enforcement Discretion (IP Section 03.04) (1 Sample)
- (1) The inspectors evaluated the licensee actions surrounding Notice of Enforcement Discretion EAF-RII-2025-0197, which can be accessed at http://www.nrc.gov/reading-rm/doc-collections/enforcement/notices/noedreactor.html, on November 15, 2025.
INSPECTION RESULTS
Inadequate Maintenance Strategy Resulting in Inoperability of the Turbine-Driven Emergency Feedwater Pump Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Pending AV 05000395/2025004-01 Open EAF-RII-2026-0008 None (NPP)71111.12 A self-revealed apparent violation (AV) of Technical Specification (TS) 6.8.1, Procedures and Programs, was identified when the licensee failed to schedule and implement a preventative maintenance procedure appropriate to the circumstances for the governor linkage for the turbine-driven emergency feedwater (TDEFW) pump, which resulted in the inoperability and unplanned unavailability of the pump.
Description:
On November 12, 2025, during routine surveillance testing of the TDEFW pump, the turbine tripped during its initial start. During troubleshooting, the licensee identified worn components on the turbine speed control governor valve assembly, specifically, the valve stem (burr at a bushing), valve stem connector (shoulder worn and pin end worn), cam crank (gouge from valve stem connector shoulder), and cam crank support (anti-rotation slot very worn and rough). These components were degraded and resulted in binding while closing the governor valve. Inspectors assessed the degradation of each subcomponent of the assembly to estimate the impact on the governor operation.
The governor valve stem is connected to the valve stem connector and kept aligned through two carbon bushings. The valve stem was found to have a minor burr which contributed to binding during full open to full closed travel. Inspectors determined that this was a contributing cause to the responsiveness of the governor, but the output of the governor should have been able to overcome the resistance absent additional issues. The licensee deburred the valve stem and restored the smooth operation through the bushing.
The valve stem connector is attached to the stem and rides in the cam plate using a cam follower, large washer, and lock nut. The valve stem connector has a cylindrical end pin that extends into the fixed cam crank support anti-rotation slot. The alignment of the cam crank, valve stem connector, washer, and anti-rotation slot keep the valve stem from rotating and keep the valve stem connector perpendicular to the cam crank during valve operation. The squared shoulder of the valve stem connector was worn from rotating into the cam crank during years of operation. The cam plate had gouges from the rotation of the valve stem connector shoulder which were located near the full-open position of the cam plate slot.
Inspectors determined that the gouging was the most significant cause of binding during pump start on November 12, 2025. The licensee replaced the valve stem connector and cam crank.
The rotation of the valve stem connector degraded both the valve stem connector and cam crank, and inspectors determined that this rotation was caused by the worn anti-rotation slot of the cam crank support and worn valve stem pin end. The bottom of the anti-rotation slot was worn significantly worse than the top of the slot due to the force of the governor assembly output.
Inspectors reviewed historical maintenance activities on the linkage between the governor and governor valve. Licensee procedure MMP-300.015, Turbine Maintenance, Emergency Feedwater Pump TPP0008, Revision 19, Section 7.4, required during governor valve maintenance, Examine linkage for wear and proper operation by manually stroking linkage to full open. Additionally, step 7.4.2 specifically required examining the radius faces of cam crank clevis for wear and even contact with surfaces. There were no additional procedure requirements to inspect linkage subcomponents.
Inspectors noted that the last governor valve preventative maintenance using Section 7.4 was performed in May 2017 (Work Order 88101005471). Inspectors noted that Section 7.4 for valve maintenance was performed in 2008, 2011, and 2017, and was scheduled for 2023, but the 2023 work order was deferred to 2027.
Inspectors noted that Section 7.17 for governor linkage adjustment did not require inspection for excessive play or degraded subcomponents.
Corrective Actions: The licensee tuned the governor, replaced components on the governor valve and linkage, and smoothed edges of the anti-rotation slot.
Corrective Action References: Condition Report (CR) 1306541 and CR1306755
Performance Assessment:
Performance Deficiency: The failure to properly pre-plan and perform maintenance that can affect the performance of safety-related equipment in accordance with written procedures, documented instructions, or drawings appropriate for the circumstances, was a performance deficiency. Specifically, the licensees failure to perform preventative maintenance appropriate to the circumstances on the governor valve linkage of the TDEFW pump was a performance deficiency that was reasonably within the licensees ability to foresee and correct.
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. Specifically, the TDEFW pump tripped during testing, rendering the pump inoperable.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power.
Inspectors used Exhibit 2, "Mitigating Systems Screening Questions," and determined that a detailed risk evaluation was required by answering question A.3, "Does the degraded condition represent a loss of the PRA function of one train of a multi-train TS system for greater than its TS allowed outage time?" as "Yes." The finding cannot be screened to Green and is pending an initial significance determination.
Cross-Cutting Aspect: Not Present Performance. No cross-cutting aspect was assigned to this finding because the inspectors determined the finding did not reflect present licensee performance.
Enforcement:
Violation: Technical Specification 6.8.1, Procedures and Programs, requires, in part, that written procedures shall be established, implemented, and maintained covering the activities referenced in the applicable procedures recommended in Appendix A of Regulatory Guide 1.33, Quality Assurance Program Requirements (Operation), Revision 2. Section 9, Procedures for Performing Maintenance, requires, in part, that maintenance that can affect the performance of safety-related equipment should be properly pre-planned and performed in accordance with written procedures, documented instructions, or drawings appropriate for the circumstances.
Contrary to the above, since 2017, the licensee failed to pre-plan or perform preventative maintenance on the TDEFW pump governor valve linkage using written procedures, documented instructions, or drawings appropriate for the circumstances, which affected the performance of this safety-related equipment. Specifically, the licensee did not provide procedural steps to identify excessive play or worn subcomponents in the governor valve linkage except during governor valve maintenance activities. Governor valve maintenance was last performed in 2017 and therefore inspections for degradation of the governor valve linkage were not scheduled appropriate to the circumstances. As a result, during surveillance testing on November 12, 2025, the degradation caused sufficient binding to cause an overspeed trip of the TDEFW pump.
Enforcement Action: This violation is being treated as an apparent violation pending a final significance (enforcement) determination.
Very Low Safety Significance Issue Resolution Process: Submittal of Licensee Event Report for Main Steam Safety Valve Failed Surveillance Testing 71111.15 This issue involves ambiguity in the applicability of regulatory requirements and inspection effort is being discontinued in accordance with the Very Low Safety Significance Issue Resolution (VLSSIR) process. No further evaluation is required.
Description:
Surveillance testing on the '2806K' code safety valve on the 'C' main steamline (MSSV) in October 2025 revealed that mechanical drift had caused the lift setpoint to lower to 1117 psig, which was lower than the Technical Specification (TS) required lift setpoint between 1176 psig +/-1 percent (1164.24 - 1187.76 psig). The inspectors reviewed the licensee's reportability review based on 10 CFR 50.73, "Licensee Event Report System," and guidance contained in NUREG-1022, "Event Report Guidelines 10 CFR 50.72 and 50.73,"
Revision 3. NUREG-1022 states, "For testing that is conducted within the required time (i.e.,
the surveillance interval plus any extension allowed by STS Surveillance Requirement (SR)3.0.2 or its equivalent), it should be assumed that the discrepancy occurred at the time of its discovery unless there is firm evidence, based on a review of relevant information such as the equipment history and the cause of failure, to indicate that the discrepancy existed previously." The inspectors noted that the safety valve unexpectedly lifted during the October 3, 2025, rapid downpower and closure of the main steam isolation valves.
Regulatory Requirement: Title 10 of the Code of Federal Regulations (10 CFR)50.73(a)(2)(i)(B) requires licensees to report any operation or condition which was prohibited by the plant's TS. License holders shall submit a Licensee Event Report (LER) for any event of the type described in 10 CFR 50.73(a) within 60 days after the discovery of the event. The licensee's TS 3.7.1.1 requires, in part, All main steam line code safety valves associated with each steam generator shall be operable with lift settings as specified in Table 3.7.2. With one or more main steamline code safety valves inoperable, operation in Modes 1, 2, and 3 may proceed provided, that within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, either the inoperable valve is restored to operable status or the Power Range Neutron High Trip Setpoint is reduced per table 3.7-1; otherwise, be in at least hot standby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in cold shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
The inspectors questioned whether the licensee failed to submit an LER within 60 days of the failed surveillance test on October 20, 2025, based on review of the equipment history and cause of the failure. The licensee performed a review of the information and determined that "firm evidence" of the valve being inoperable for greater than the TS allowed outage time did not exist. Based on the term "firm evidence" in the reportability guidance in NUREG-1022, the inspectors concluded ambiguity existed to determine if the regulatory requirement in 10 CFR 50.73(a)(2)(i)(B) was met.
Significance: The NRC Enforcement Policy provides an example of a Severity Level IV (SL-IV) violation under Section 6.9.d.9 as "A licensee fails to make a report required by 10 CFR 50.72 or 10 CFR 50.73." The failure to report the issue would have been considered an SL-IV if processed via the Enforcement Policy as a violation.
Technical Assistance Request: The inspectors did not request technical assistance.
Corrective Action Reference: CR1304488, CR1302820, and CR1303919 Licensee-Identified Non-Cited Violation 71111.24 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: 10 CFR 50.155(b)(1), Mitigation of beyond-design-basis events: Strategies and guidelines, states, in part, each licensee shall develop, implement, and maintain: Mitigation strategies for beyond-design basis external events - Strategies and guidelines to mitigate beyond-design-basis external events from natural phenomena that are developed assuming a loss of all AC power concurrent with either a loss of normal access to the ultimate heat sink or, for passive reactor designs, a loss of normal access to the normal heat sink. These strategies and guidelines must be capable of being implemented site-wide and must include the following: Maintaining or restoring core cooling, containment, and spent fuel pool cooling capabilities. 10 CFR 50.155(c), Equipment, states, in part,
- (1) The equipment relied on for the mitigation strategies and guidelines required by paragraph (b)(1) of this section must have sufficient capacity and capability to perform the functions required by paragraph (b)(1) of this section.
Contrary to the above, since the implementation of the FLEX strategy in 2012, the licensee failed to implement and maintain strategies and guidelines to mitigate beyond-design basis external events as required by 10 CFR 50.155(b)(1) and failed to ensure equipment relied on for the mitigation strategies and guidelines had sufficient capacity and capability to perform the functions as required by 10 CFR 50.155(c)(1). Specifically, the licensee failed to establish appropriate FLEX combustion turbine generators protection system settings to support the FLEX strategy for restoring steam generator feed.
Significance/Severity: Green. A detailed risk assessment was required since the finding involved equipment credited in FLEX strategy such that a FLEX function could not be completed within the time allotted. A regional Senior Reactor Analyst (SRA) performed a detailed risk assessment using SAPHIRE 8 Version 8.2.12 and the V.C. Summer SPAR Model Version 8.82 dated May 14, 2025. The SRA assumed the maximum one-year exposure time and set basic events FLX-CTG-FR-11 and FLEX-CTG-FR-12 to true to model the FLEX combustion turbine generators failing to run when loaded. The dominant accident sequence was a fire-induced plant-centered loss of offsite power, failure of an emergency diesel generator, failure of the FLEX diesel-driven steam generator makeup pump, failure of operators to manually control the turbine-driven emergency feedwater pump, failure of the FLEX 480 VAC diesel, and operators failing to recover onsite or offsite power in 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. The change in core damage frequency was less than 1E-6 and change in large early release frequency was less than 1E-7 corresponding to a finding of very low safety significance (GREEN).
Corrective Action References: CR-20-01919, CR1280601, CR1301078
EXIT MEETINGS AND DEBRIEFS
The inspectors verified that no proprietary information was retained or documented in this report.
- On January 21, 2026, the inspectors presented the integrated inspection results to Beth Jenkins, Site Vice President, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Reactor Trip or Safety Injection
Procedures
GOP-4A
Power Operation (Mode 1 - Ascending)
Corrective Action
Documents
CR1298289
Battery Room Damper PMs are Past Due Date
08/13/2025
Engineering
Evaluations
LEE -
CA13312993
Level of Effort Evaluation for Control Room Air Handling Unit
'A' Inlet Control Damper Failure
07/01/2025