ML25323A276
| ML25323A276 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 11/19/2025 |
| From: | Matthew Fannon, Mark Franke NRC/RGN-II/DORS/PB2 |
| To: | |
| References | |
| MD 8.3 | |
| Download: ML25323A276 (10) | |
Text
1 : Decision Documentation for Reactive Inspection (Deterministic and Risk Criteria Analyzed)
Decision Documentation for Reactive Inspection (Deterministic and Risk Criteria Analyzed)
Note: The results of this assessment are based on an initial or preliminary set of information and do not prejudge or imply deficient performance on the part of the licensee or the lack thereof. The purpose of this assessment is to determine whether to conduct a reactive inspection; it is independent of determining the significance of any inspection findings that may be associated with these circumstances.
PLANT:
V.C. Summer EVENT DATE: 11/12/2025 EVALUATION DATE: 11/13/2025 Brief Description of the Significant Event or Degraded Condition:
At 2:08 a.m. on November 12, 2025, V.C. Summer initiated quarterly testing of the turbine-driven emergency feedwater (TDEFW) pump. Within seconds of starting, control room indications showed pump speed increasing to the expected normal range before it tripped on overspeed.
This is the third failure of the TDEFW pump this year (3/4/2025 and 8/19/2025). The cause of the failure is due to binding in the governor to governor valve linkage. The third failure differs from the previous two which were associated with the overspeed trip device and governor speed control.
Y/N DETERMINISTIC CRITERIA Involved operations that exceeded, or were not included in, the design bases of the facility N
Remarks: Not applicable to this assessment (N/A)
Involved a major deficiency in design, construction, or operation having potential generic safety implications N
Remarks: N/A Led to a significant loss of integrity of the fuel, primary coolant pressure boundary, or primary containment boundary of a nuclear reactor N
Remarks: N/A Led to the loss of a safety function or multiple failures in systems used to mitigate an actual event N
Remarks: N/A Involved possible adverse generic implications N
Remarks: The terry turbine maintenance guide from EPRI and licensee procedures cover inspection and adjustments of valve linkage. Valve linkage adjustments are well understood by industry.
2 Involved significant unexpected system interactions N
Remarks: N/A Involved repetitive failures or events involving safety-related equipment or deficiencies in operations N
Remarks: This is the third failure of the TDEFW pump this year (3/4/2025 and 8/19/2025). The 3/4/2025 failure was due to inadequate setup of a newly refurbished governor which failed to ensure the pneumatic control air port was vented. The 8/19/2025 failure was due to wear on the overspeed trip device tappet nut. The cause of the 11/12/2025 failure is binding in the governor to governor valve linkage.
IMC 0309 Exhibit 1: Additional Guidance and Examples states that isolated surveillance test failures not readily known to be repetitive would not generally warrant MD 8.3 evaluation unless exacerbated by other issues or complexities.
Involved questions or concerns pertaining to licensee operational performance N
Remarks: N/A CONDITIONAL RISK ASSESSMENT RISK ANALYSIS BY: N/A DATE: N/A Brief Description of the Basis for the Assessment (may include assumptions, calculations, references, peer review, or comparison with licensees results):
N/A - No deterministic criteria were met The estimated conditional core damage probability (CCDP) is ___________________ and places the risk in the range of a _______________ and ____________________ inspection.
3 : Decision Documentation for Reactive Inspection and Examples (Deterministic-only Criteria Analyzed)
Decision Documentation for Reactive Inspection (Deterministic-only Criteria Analyzed)
Note: The results of this assessment are based on an initial or preliminary set of information and do not prejudge or imply deficient performance on the part of the licensee or the lack thereof. The purpose of this assessment is to determine whether to conduct a reactive inspection; it is independent of determining the significance of any inspection findings that may be associated with these circumstances.
PLANT: V.C. Summer EVENT DATE: 11/12/2025 EVALUATION DATE: 11/13/2025 Brief Description of the Significant Event or Degraded Condition:
See Enclosure 1 Above REACTOR SAFETY Y/N IIT Deterministic Criteria Led to a Site Area Emergency N
Remarks: N/A Exceeded a safety limit of the licensee's technical specifications N
Remarks: N/A Involved circumstances sufficiently complex, unique, or not well enough understood, or involved safeguards concerns, or involved characteristics the investigation of which would best serve the needs and interests of the Commission N
Remarks: N/A
4 Y/N SI Deterministic Criteria Significant failure to implement the emergency preparedness program during an actual event, including the failure to classify, notify, or augment onsite personnel N
Remarks: N/A Involved significant deficiencies in operational performance which resulted in degrading, challenging, or disabling a safety system function or resulted in placing the plant in an unanalyzed condition for which available risk assessment methods do not provide an adequate or reasonable estimate of risk.
N Remarks: N/A
5 RADIATION SAFETY Y/N IIT Deterministic Criteria Led to a significant radiological release (levels of radiation or concentrations of radioactive material in excess of 10 times any applicable limit in the license or 10 times the concentrations specified in 10 CFR Part 20, Appendix B, Table 2, when averaged over a year) of byproduct, source, or special nuclear material to unrestricted areas N
Remarks: N/A Led to a significant occupational exposure or significant exposure to a member of the public. In both cases, significant is defined as five times the applicable regulatory limit (except for shallow-dose equivalent to the skin or extremities from discrete radioactive particles)
N Remarks: N/A Involved the deliberate misuse of byproduct, source, or special nuclear material from its intended or authorized use, which resulted in the exposure of a significant number of individuals N
Remarks: N/A Involved byproduct, source, or special nuclear material, which may have resulted in a fatality N
Remarks: N/A Involved circumstances sufficiently complex, unique, or not well enough understood, or involved safeguards concerns, or involved characteristics the investigation of which would best serve the needs and interests of the Commission N
Remarks: N/A Y/N AIT Deterministic Criteria Led to a radiological release of byproduct, source, or special nuclear material to unrestricted areas that resulted in occupational exposure or exposure to a member of the public in excess of the applicable regulatory limit (except for shallow-dose equivalent to the skin or extremities from discrete radioactive particles)
N Remarks: N/A
6 Involved the deliberate misuse of byproduct, source, or special nuclear material from its intended or authorized use and had the potential to cause an exposure of greater than 5 rem to an individual or 500 mrem to an embryo or fetus N
Remarks: N/A Involved the failure of radioactive material packaging that resulted in external radiation levels exceeding 10 rads/hr or contamination of the packaging exceeding 1000 times the applicable limits specified in 10 CFR 71.87 N
Remarks: N/A Involved the failure of the dam for mill tailings with substantial release of tailings material and solution off site N
Remarks: N/A Y/N SI Deterministic Criteria May have led to an exposure in excess of the applicable regulatory limits, other than via the radiological release of byproduct, source, or special nuclear material to the unrestricted area; specifically occupational exposure in excess of the regulatory limits in 10 CFR 20.1201 exposure to an embryo/fetus in excess of the regulatory limits in 10 CFR 20.1208 exposure to a member of the public in excess of the regulatory limits in 10 CFR 20.1301 N
Remarks: N/A May have led to an unplanned occupational exposure in excess of 40 percent of the applicable regulatory limit (excluding shallow-dose equivalent to the skin or extremities from discrete radioactive particles)
N Remarks: N/A Led to unplanned changes in restricted area dose rates in excess of 20 rem per hour in an area where personnel were present or which is accessible to personnel N
Remarks: N/A Led to unplanned changes in restricted area airborne radioactivity levels in excess of 500 DAC in an area where personnel were present or which is accessible to personnel and where the airborne radioactivity level was not promptly recognized and/or appropriate actions were not taken in a timely manner N
Remarks: N/A
7 Led to an uncontrolled, unplanned, or abnormal release of radioactive material to the unrestricted area for which the extent of the offsite contamination is unknown; or, that may have resulted in a dose to a member of the public from loss of radioactive material control in excess of 25 mrem (10 CFR 20.1301(e)); or, that may have resulted in an exposure to a member of the public from effluents in excess of the ALARA guidelines contained in Appendix I to 10 CFR Part 50 N
Remarks: N/A Led to a large (typically greater than 100,000 gallons), unplanned release of radioactive liquid inside the restricted area that has the potential for ground-water, or offsite, contamination N
Remarks: N/A Involved the failure of radioactive material packaging that resulted in external radiation levels exceeding 5 times the accessible area dose rate limits specified in 10 CFR Part 71, or 50 times the contamination limits specified in 49 CFR Part 173 N
Remarks: N/A Involved an emergency or non-emergency event or situation, related to the health and safety of the public or on-site personnel or protection of the environment, for which a 10 CFR 50.72 report has been submitted that is expected to cause significant, heightened public or government concern N
Remarks: N/A
8 SAFEGUARDS/SECURITY Y/N IIT Deterministic Criteria Involved circumstances sufficiently complex, unique, or not well enough understood, or involved safeguards concerns, or involved characteristics the investigation of which would best serve the needs and interests of the Commission N
Remarks: N/A Failure of licensee significant safety equipment or adverse impact on licensee operations as a result of a safeguards-initiated event (e.g., tampering).
N Remarks: N/A Actual intrusion into the protected area N
Remarks: N/A Y/N AIT Deterministic Criteria Involved a significant infraction or repeated instances of safeguards infractions that demonstrate the ineffectiveness of facility security provisions N
Remarks: N/A Involved repeated instances of inadequate nuclear material control and accounting provisions to protect against theft or diversions of nuclear material N
Remarks: N/A Confirmed tampering event involving significant safety or security equipment N
Remarks: N/A Substantial failure in the licensees intrusion detection or package/personnel search procedures which results in a significant vulnerability or compromise of plant safety or security N
Remarks: N/A
9 Y/N SI Deterministic Criteria Involved inadequate nuclear material control and accounting provisions to protect against theft or diversion, as evidenced by inability to locate an item containing special nuclear material (such as an irradiated rod, rod piece, pellet, or instrument)
N Remarks: N/A Involved a significant safeguards infraction that demonstrates the ineffectiveness of facility security provisions N
Remarks: N/A Confirmation of lost or stolen weapon N
Remarks: N/A Unauthorized, actual non-accidental discharge of a weapon within the protected area N
Remarks: N/A Substantial failure of the intrusion detection system (not weather related)
N Remarks: N/A Failure to the licensees package/personnel search procedures which results in contraband or an unauthorized individual being introduced into the protected area N
Remarks: N/A Potential tampering or vandalism event involving significant safety or security equipment where questions remain regarding licensee performance/response or a need exists to independently assess the licensees conclusion that tampering or vandalism was not a factor in the condition(s) identified N
Remarks: N/A
10 RESPONSE DECISION USING THE ABOVE INFORMATION AND OTHER KEY ELEMENTS OF CONSIDERATION AS APPROPRIATE, DOCUMENT THE RESPONSE DECISION TO THE EVENT OR CONDITION, AND THE BASIS FOR THAT DECISION DECISION AND DETAILS OF THE BASIS FOR THE DECISION:
None of the deterministic criteria were met. Therefore, no reactive inspection is required. IMC 0309 Exhibit 1: Additional Guidance and Examples does not generally warrant MD 8.3 evaluations for isolated surveillance test failures not readily known to be repetitive unless they are exacerbated by other issues that contributed to those events and conditions or complexities that occurred because of those events and conditions. The TDEFW pump failure was not a repeat of a previous failure condition nor exacerbated by other issues or complexities. Both of the previous issues have been thoroughly inspected and evaluated. The first is documented in the V.C. Summer second quarter integrated inspection report (ML25213A008) and the second issue has been inspected and is pending inspection report issuance. The MD 8.3 evaluation of the third issue was documented to explain the differences in failure mechanisms and the decision for the resident office to perform routine baseline inspection.
Inspection Follow-up Determination: No reactive inspection recommended.
BRANCH CHIEF REVIEW:
DIVISION DIRECTOR REVIEW:
ADAMS ACCESSION NUMBER: ML25323A276 EVENT NOTIFICATION REPORT NUMBER (as applicable): N/A Profiled using template NRR-123 (ML18233A547 (non-public))
Signed by Fannon, Matthew on 11/19/25 Signed by Franke, Mark on 11/19/25