IR 05000461/2025004
| ML26040A159 | |
| Person / Time | |
|---|---|
| Site: | Clinton  (NPF-062) |
| Issue date: | 02/10/2026 |
| From: | Robert Ruiz NRC/RGN-III/DORS/RPB1 |
| To: | Mudrick C Constellation Energy Generation |
| References | |
| IR 2025004 | |
| Download: ML26040A159 (0) | |
Text
SUBJECT:
CLINTON POWER STATION - INTEGRATED INSPECTION REPORT 05000461/2025004
Dear Christopher H. Mudrick:
On December 31, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Clinton Power Station. On January 23, 2026, the NRC inspectors discussed the results of this inspection with F. Payne, Site Vice President, 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. None of these findings involved a violation of NRC requirements.
If you disagree with a cross-cutting aspect assignment or a finding not associated with a regulatory requirement 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 Clinton Power Station.
February 10, 2026 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, Robert Ruiz, Chief Reactor Projects Branch 1 Division of Operating Reactor Safety Docket No. 05000461 License No. NPF-62 Enclosure:
As stated cc w/ encl: Distribution via GovDelivery Signed by Ruiz, Robert on 02/10/26
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Clinton 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
Failure to follow Preventive Maintenance Revision Process Leads to Servovalve Failure and Automatic Scram on High Water Level Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green FIN 05000461/2025004-01 Open/Closed
[H.14] -
Conservative Bias 71111.13 A Green finding of site procedure WC-AA-120, Preventive Maintenance (PM) Database Revision Requirements, and AD-AA-3000, Nuclear Risk Management, was self-revealed when the plant scrammed on high reactor water level. Equipment failure analysis revealed the failure mechanism to be metallic particulate silt accumulation in the Electro-Hydraulic Control (EHC)servovalve causing the valve to become stuck in the open position leading to the overfeeding event. Specifically, the servovalve failed due to the sites decision to extend the servovalve replacement frequency from every 3 refueling outages (O3) to every 4 refueling outages (O4), in 2024, without a technically robust risk assessment and screening per the sites preventive maintenance change processes.
Failure to Follow Parts Quality Process Leads to Turbine Electro-Hydraulic Control Oil Leak and Manual Scram Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green FIN 05000461/2025004-02 Open/Closed None (NPP)71111.13 A Green finding of SM-AC-3019, Parts Quality Process, was self-revealed when the operators inserted a manual scram due to low EHC oil level. Specifically, Clinton failed to properly screen the turbine control valve actuator into the Parts Quality Initiative (PQI) program, and therefore inadequately tested the actuator prior to accepting it into inventory. This resulted in the #3 Turbine Control Valve (TCV3) actuator being installed in 2018 and subsequently failing in the fall of 2025, causing an un-isolable EHC rupture in the heater bay resulting in a low EHC oil level (-24.5"), which led to a procedurally-required manual scram.
Additional Tracking Items
None.
PLANT STATUS
Unit 1 began the inspection period in Mode 4, cold shutdown, due to the ongoing refueling outage, C1R22. The reactor achieved criticality on October 2, 2025. The generator was synchronized to the grid on October 4, 2025, ending refueling outage C1R22. Later, on October 4, 2025, the generator tripped on differential overcurrent, and the site entered forced outage C1F65. The reactor remained stable at 14 percent rated thermal power (RTP).
Following repair activities, the generator was synchronized to the grid following C1F65 on October 5, 2025.
On October 6, 2025, during reactor startup, Unit 1 automatically scrammed on high reactor water level when operating at 23 percent RTP. The unit subsequently entered Mode 3 and forced outage C1F66 due to the automatic scram. Following repair activities, the reactor achieved criticality on October 7, 2025, and synchronized to the grid on October 8, 2025.
The reactor achieved approximately 95 percent RTP on October 11, 2025. Reactor power was subsequently lowered to approximately 70 percent RTP for a planned rod pattern adjustment and then raised back to 95 percent RTP. On October 13, 2025, reactor power was lowered to approximately 70 percent RTP for a planned rod pattern adjustment. Reactor power was subsequently raised to approximately 100 percent RTP on October 14, 2025.
On October 22, 2025, Unit 1 reactor power was lowered from approximately 100 percent RTP to 86 percent RTP to support mitigation actions in combating an EHC fluid leak from the #3 turbine control valve positioner. The reactor was subsequently manually scrammed from approximately 86 percent RTP due to low level in the EHC reservoir. Unit 1 subsequently entered Mode 3 and forced outage C1F67. Unit 1 entered Mode 4, cold shutdown, on October 24, 2025. Following repair activities, the reactor achieved criticality on October 29, 2025. The reactor synchronized to the grid on October 30, 2025. The reactor achieved approximately 95 percent RTP on November 1, 2025. Power was lowered to approximately 70 percent RTP for a planned rod pattern adjustment and then restored to 95 percent RTP on the same day. Power was raised to approximately 100 percent RTP on November 2, 2025.
On November 14, 2025, Unit 1 had a complete loss of offsite power to vital busses due to the emergency reserve auxiliary transformer (ERAT) tripping during a planned maintenance outage window on the B reserve auxiliary transformer (RAT). This resulted in the sites required declaration of a Notice of Unusual Event (emergency action level MU.1). All three emergency diesel generators auto-started and reenergized the vital busses with no challenges. The site completed repairs and restoration on November 16, 2025, and exited the Unusual Event.
The unit was restored to a normal electrical lineup that same evening.
On November 19, 2025, Unit 1 power was reduced to approximately 75 percent RTP for a planned rod pattern adjustment. Power was restored to approximately 100 percent RTP on November 20, 2025, following successful completion of the rod pattern adjustment.
On December 7, 2025, Unit 1 power was reduced to approximately 70 percent RTP, for a planned rod pattern adjustment. Power was restored to approximately 100 percent RTP on December 8, 2025, following successful completion of the rod pattern adjustment.
The reactor remained at or near approximately 100 percent RTP until the end 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
Seasonal Extreme Weather Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated readiness for seasonal extreme winter weather conditions prior to the onset of seasonal cold temperatures for the following systems:
diesel generators, emergency reserve auxiliary transformer (ERAT), reserve auxiliary transformer (RAT), and shutdown service water (SX) systems on December 5th, 2025
71111.04 - Equipment Alignment
Complete Walkdown Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated system configurations during a complete walkdown of the reactor core isolation cooling (RCIC) system ending on October 29th, 2025.
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (3 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)707 Auxiliary: RCIC pump room on December 1, 2025 (2)825 Control: control room HVAC on December 10, 2025 (3)777 Turbine: general access and mezzanine on December 22, 2025
71111.11A - Licensed Operator Requalification Program and Licensed Operator Performance
Requalification Examination Results (IP Section 03.03) (1 Sample)
- (1) The inspectors reviewed and evaluated the licensed operator examination failure rates for the requalification annual operating exam and annual written exam administered between October 22, 2025, and December 5, 2025.
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 License Operator Requalification Examinations on October 28, 2025.
71111.12 - Maintenance Effectiveness
Maintenance Effectiveness (IP Section 03.01) (2 Samples)
The inspectors evaluated the effectiveness of maintenance to ensure the system structures, systems, and components (SSCs) remain capable of performing their intended function:
(1)feedwater system with focus on valve maintenance practices completed on November 13, 2025 (2)fire protection systems completed on December 15, 2025
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (4 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) The inspectors evaluated the thoroughness of work completion, work management, and risk associated to the containment fire protection header containment isolation valves (1FP050 and 1FP092) leakage repair and testing under Work Order (WO) 05725664 ending on October 27, 2025.
- (2) The inspectors evaluated the thoroughness of work completion, work management, and risk associated with the reactor water cleanup (RT) drain line containment isolation valve to radwaste (1WX020) secondary containment repair under WO 05615967 ending on October 27, 2025.
- (3) The inspectors evaluated the thoroughness of work completion, work management, and risk associated with the RPS level 8 scram and turbine driven reactor feed pump servo motor replacement under WO 05732014.
- (4) The inspectors evaluated the thoroughness of work completion, work management, and risk associated with the #3 turbine control valve hydraulic oil rupture and manual scram under WO 05739914.
71111.20 - Refueling and Other Outage Activities
Refueling/Other Outage Sample (IP Section 03.01) (2 Samples)
- (1) The inspectors evaluated refueling outage 1CR22 activities beginning on September 8, 2025, and ending on October 4, 2025.
- (2) The inspectors evaluated forced outage 1CF67 beginning on October 22, 2025, and ending on October 29, 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) (1 Sample)
(1)reserve auxiliary transformer risk informed completion time system outage window and system restoration from November 10, 2025, to November 16, 2025
Surveillance Testing (IP Section 03.01) (2 Samples)
(1)division I diesel generator integrated testing under WO 05449881
- (2) scram discharge volume vent valve stroke and flow scan on October 1, 2025
Containment Isolation Valve (CIV) Testing (IP Section 03.01) (1 Sample)
(1)main steam line containment isolation local leak rate testing completed on October 27, 2025, under WO 5161467
71114.04 - Emergency Action Level and Emergency Plan Changes
Inspection Review (IP Section 02.01-02.03) (1 Sample)
- (1) The inspectors evaluated the following submitted Emergency Action Level and Emergency Plan changes.
- EP-AA-1000, Standardized Radiological Emergency Plan, Revision 34
- EP-AA-1003 Addendum 3, Constellation Emergency Action Levels for Clinton Station, Revision 9 This evaluation does not constitute NRC approval.
71114.06 - Drill Evaluation
Additional Drill and/or Training Evolution (1 Sample)
The inspectors evaluated:
- (1) frazil ICE scenario with DEP opportunity
OTHER ACTIVITIES - BASELINE
71152A - Annual Follow-up Problem Identification and Resolution
Annual Follow-up of Selected Issues (Section 03.03) (2 Samples)
The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:
(1)
- RAT B mechanically switched capacitor EC, refueling outage MSC trips during condensate pump starts and load tap changer excessive tapping (2)
- RCIC turbine trip valve wiring discrepancy and RCIC 1E51F076 overthrust event
71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02) (1 Sample)
- (1) The inspectors reviewed the licensees corrective action program to identify potential trends in configuration control events that might be indicative of a more significant safety issue.
71153 - Follow-up of Events and Notices of Enforcement Discretion Event Follow-up (IP Section 03.01) (1 Sample)
- (1) Complete loss of offsite power and ERAT during RAT B System Outage Window from November 14, 2025, to November 16, 2025.
Personnel Performance (IP Section 03.03) (2 Samples)
- (1) The inspectors evaluated the automatic reactor scram on high reactor water level due to turbine driven reactor feed pump overfeeding and licensees response on October 6, 2025.
- (2) The inspectors evaluated the manual scram due to turbine controls EHC oil leak and licensees response on October 22, 2025.
INSPECTION RESULTS
Failure to follow Preventive Maintenance Revision Process Leads to Servovalve Failure and Automatic Scram on High Water Level Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green FIN 05000461/2025004-01 Open/Closed
[H.14] -
Conservative Bias 71111.13 A Green finding of site procedure WC-AA-120, Preventive Maintenance (PM) Database Revision Requirements, and AD-AA-3000, Nuclear Risk Management, was self-revealed when the plant scrammed on high reactor water level. Equipment failure analysis revealed the failure mechanism to be metallic particulate silt accumulation in the EHC servovalve causing the valve to become stuck in the open position leading to the overfeeding event.
Specifically, the servovalve failed due to the sites decision to extend the servovalve replacement frequency from every 3 refueling outages (O3) to every 4 refueling outages (O4),in 2024, without a technically robust risk assessment and screening per the sites preventive maintenance change processes.
Description:
On October 6, 2025, at 0321 Clinton Power Station, Unit 1, automatically scrammed on high reactor water level while placing the turbine driven reactor feed pump (TDRFP) A in service as a part of starting up the reactor after the most recent refueling outage, C1R22.
The reactor scram was uncomplicated and the operators in the control room performed their post-scram actions with no challenges.
The sites failure analysis concluded that the failure mechanism was metallic particulate/silt accumulation in the tight/narrow passages between the servo valve control swing plate and the valve body. This metallic silt accumulation led to increased frictional forces preventing the swing plate from restoring to the neutral/center position leading to hydraulic pressure shunting the TDRFP hydraulic operating cylinder to the full open position and leading to the overfeeding event. Furthermore, the failure analysis concluded that this failure mechanism aligned with an industry-known failure mode similar to spool-valve silting, in which small particles accumulate within tight hydraulic tolerances and restrict motion.
Additionally, when the servo valve that failed via the silt locking mechanism was calibrated in 2019 as a part of the post-maintenance testing of the servo position controller (SPC),the SPC was left with controller gain values that did not completely eliminate excess oscillations from the control scheme. These additional oscillations could have contributed to excessive wear of the servo valve due to increased motion and abrasion between the valve body and the swing plate leading to the silt lock mechanism that resulted in the high water level scram.
On July 9, 2024, the site approved preventive maintenance modification request (PMMR),
Preventive Maintenance Change (PMC)-24-149999, to permanently change the frequency of the TDRFP servovalve replacement from every 3 refueling outages (6 year frequency) to every 4 refueling outages (8 year frequency) contrary to original equipment manufacturer (OEM) guidance and Exelon EHC High Impact Team (HIT) guidance. This moved the planned replacement from the most recent refueling outage, C1R22 to C1R23. If replaced in C1R22, the servovalve would have reasonably not failed due to silt lock and would have prevented the high level scram from occurring. The basis for the decision to move out the servo valve replacement was based on a technical review, and risk assessment performed as part of the PMMR process.
The technical review required per station procedure WC-AA-120, Preventive Maintenance Database Revision Requirements, Section 6.2.4.c, used the fact that the as-found condition of the servovalves was always satisfactory over the last 20 years as basis to extend the PM frequency. However, the as-found condition review only included visual cleanliness inspections of the servovalve, and did not include, nor require, a detailed inspection of the hydraulic or electrical components of the servovalve. Contrary to, PMMR E-Strategy Tool, WC-AA-120-F-02, Step 46, which states, in part, ensure planned PM Modification is technically sound, utilizing the as-found visual cleanliness review as a basis for extending frequency was not technically sound because visual cleanliness is not sufficient to be a predicative/leading metric/indicator for the applicable potential failure mechanismsspecifically, the silting mechanism that led to the high water level scram.
Additionally, the site performed a risk assessment per, AD-AA-3000, Nuclear Risk Management Process, as a part of PMC-24-149999, which was prompted by WC-AA-120, Section 6.4.4, which states, in part, Risk assessments may be requested for potential high consequence issues per AD-AA-3000. The risk assessment from PMC-24-149999, completed in July 2024, concluded that the risk from the servovalve was LOW due to the likelihood of an event being low per AD-AA-3000. However, the safety culture assessment, performed as a part of the causal evaluation in response to the high water level scram, concluded the servo PM was changed from O3 to O4 without robust risk assessment. The basis for this conclusion was the fact that AD-AA-3000 requires both likelihood and consequences to be considered in the risk assessment via a likelihood-consequence significance matrix.
The consequence analysis was accurate in determining a potential significance 2 event (i.e., scram/transient), but the likelihood analysis resulted in a LOW result without consideration of potential unknown factors. The risk assessment and ultimate likelihood conclusion lacked robustness because only one electrical failure mechanism was considered in PMC-24-149999 when multiple failure modes were possible, and plausible, both mechanically and electrically. The lack of control with potential failure mechanisms suggests this issue was more complex. Additionally, the unknown factors in relation to the potential failure modes as discussed in AD-AA-3000, Attachment 1, Risk Assessment and Ranking Process, states in part, The more known about conditions that influence the risk item and resulting consequences, the higher the certainty or predictability of that probability and the lower the likelihood would have resulted in a higher likelihood result than LOW. Failure mechanisms, like the silting mechanism that led to the scram, were not considered, and even if considered, would have a lack of predictability due to the nature of the failure mechanism.
These additional possible failure mechanisms with lack of predictability would have driven the risk matrix likelihood result higher than LOW leading to a different conclusion from the risk assessment in PMC 24-149999 and could have reasonably prevented the servo valve replacement frequency change from O3 to O4.
Ultimately, the site failed to follow the requirements of WC-AA-120 by performing a cursory risk assessment in support of the PMMR, and a lack of robust technical review with respect to technical basis and work history. This resulted in the PM frequency being extended from O3 to O4, which ultimately led to the scram on high water level event on October 6, 2025.
Corrective Actions:
In response to the high water level scram, the site replaced the servo valve on both the A and B TDRFPs. Additionally, the site completed a root cause evaluation to gain further insights and mitigate recurrence.
Corrective Action References: AR 04903283
Performance Assessment:
Performance Deficiency:
The licensees failure to follow WC-AA-120, Preventive Maintenance Database Revision Requirements, with respect to performance of an adequate risk assessment ranking in accordance with AD-AA-3000 Attachment 1, Risk Assessment and Ranking Process, and robust technical review in accordance with WC-AA-120-F-02, step 45 and 46, PMMR E-Strategy PMMR Tool, was a performance deficiency.
Screening:
The inspectors determined the performance deficiency was more-than-minor because it was associated with the Equipment Performance 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 performance deficiency resulted in the failure of the A TDRFP control system to adequately perform its function resulting in overfeeding the reactor vessel and an automatic scram on high water level. Examples 4.b and 5.b in IMC 0612 Appendix E Examples of Minor Issues supports the more-than-minor determination.
Significance:
The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power.
Specifically, all the questions in IMC 0609 Appendix A, The Significance Determination Process (SDP) For Findings At-Power, Exhibit 1, Initiating Events Screening Questions were answered No.
Cross-Cutting Aspect:
H.14 - Conservative Bias: Individuals use decision-making practices that emphasize prudent choices over those that are simply allowable. A proposed action is determined to be safe in order to proceed, rather than unsafe in order to stop. Specifically, the driver behind the failure to follow WC-AA-120 with respect to changing PM frequency, technical rigor, and risk assessment, points toward decision-making that prioritized protection of outage schedule and scope over ensuring plant equipment reliability.
Enforcement:
Inspectors did not identify a violation of regulatory requirements associated with this finding.
Failure to Follow Parts Quality Process Leads to Turbine Electro-Hydraulic Control Oil Leak and Manual Scram Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green FIN 05000461/2025004-02 Open/Closed None (NPP)71111.13 A Green finding of SM-AC-3019, Parts Quality Process, was self-revealed when the operators inserted a manual scram due to low Electro-Hydraulic Control (EHC) oil level. Specifically, the licensee failed to properly screen the turbine control valve actuator into the Parts Quality Initiative (PQI) program, and therefore inadequately tested the actuator prior to accepting it into inventory. This resulted in the #3 Turbine Control Valve (TCV3) actuator being installed in 2018 and subsequently failing in the fall of 2025, causing an un-isolable EHC rupture in the heater bay resulting in a low EHC oil level (-24.5"), which led to a procedurally-required manual scram.
Description:
On October 22, 2025, Clinton Power Station manually scrammed from low EHC oil level while operating at approximately 86 percent rated thermal power. The reactor scram was uncomplicated and the operators in the control room performed their post-scram actions with no challenges.
The site concluded that the failure was the #3 Turbine Control Valve (TCV3) actuator, including a dislodged backing plate, four of the eight tie rods sheared, and two of the remaining tie rods were under-torqued, resulting in an un-isolable EHC rupture. The sites extent of condition included resonance testing on tie rods and identifying multiple under-torqued (<500 ft-lbs) tie rods on both currently installed and spare actuators. The failure analysis identified the under-torquing of tie rods increased cyclic stress on the actuator to the point of shearing. The sheared tie rods allowed leakage of pressurized EHC fluid to spray out, leading to failure of the TCV3 actuator and coating the heater bay and below levels of the Turbine Building in EHC fluid.
On March 12, 2009, the site incorrectly screened the turbine control valve actuator in accordance with procedure SM-AC-3019, Parts Quality Process, documenting on their inventory control program, in part...used on a Risk Significant System (TG [turbine generator]). However, the actuator itself does not require any additional PQI testing.
The Parts Quality Process Section 7.1.1 identifies the Catalog Identification (CatID) should be verified for PQI applicability when in receipt of a new potential PQI item. Parts Quality Process Attachment 2, PQI Component Inclusion List provides a recommended list of PQI components including Valve Positioners. Clintons evaluation of the manual scram event noted the breakdown was a Parts/Vendor Quality Issue. The inspectors determined the licensee did not follow their procedure Parts Quality Process Section 7.1.1 step 2 to properly screen the actuator (valve positioner) as PQI which directs the site to assess in part if in-house testing, [...], or enhanced receipt inspection are necessary to verify quality of the part. Specifically, if screened correctly the site would have had the opportunity to perform additional non-invasive testing, like resonance frequency testing of the bolted tie rods or torque checks, as part of the PQI process. Not performing the testing produced a vulnerability which caused a mechanical failure resulting in a manual reactor scram.
Corrective Actions:
In response to the manual scram, the site resonance frequency tested the three remaining Turbine Control Valves, all four Main Turbine Stop Valves and Intermediate Valves, and all six Main Turbine Bypass Valves to assess tie rod torquing. Additionally, the site will implement periodic resonance frequency testing on actuators and require a Certificate of Conformance from the vendor for torque specifications on tie rods. The licensee completed a Corrective Action Program Evaluation (CAPE) following the event. Constellation corporate engineering is also determining a long-term strategy for tie rods evaluations.
Corrective Action References: AR 04908061
Performance Assessment:
Performance Deficiency:
In March 2009, the licensees failure to follow SM-AC-3019, Parts Quality Process, procedure to screen and test the turbine control valve actuators as Parts Quality Initiative components correctly was a performance deficiency.
Screening:
The inspectors determined the performance deficiency was more-than-minor because it was associated with the Equipment Performance 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 performance deficiency resulted in the failure of the
- 3 Turbine Control Valve actuator which prompted the Electro-Hydraulic Control low oil level manual scram. Examples 4.b and 5.b in IMC 0612 Appendix E Examples of Minor Issues supports the more-than-minor determination.
Significance:
The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power.
Specifically, all the questions in IMC 0609 Appendix A, The Significance Determination Process (SDP) For Findings At-Power, Exhibit 1, Initiating Events Screening Questions were answered No.
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. Specifically, the performance deficiency occurred on March 12, 2009, and does not reflect present licensee performance.
Enforcement:
Inspectors did not identify a violation of regulatory requirements associated with this finding.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On January 23, 2026, the inspectors presented the integrated inspection results to F. Payne, Site Vice President, and other members of the licensee staff.
- On December 8, 2025, the inspectors presented the emergency preparedness inspection results to R. Lorch, Emergency Preparedness Manager, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Winter Readiness-Heater 1SH05AC Not Working
10/10/2025
Winter Readiness: RWT Chemical Feed Tray
11/05/2025
Corrective Action
Documents
Degraded Winter Readiness of MPW Trailer
11/09/2025
Miscellaneous
Clean Power
Station Winter
Readiness
Certification
Clean Power Station Winter Readiness Certification
10/31/2025
Corrective Action
Documents
1E51C003 Further Degradation into Action Range
10/04/2025
Procedures
3310.01
Reactor Core Isolation Cooling
034
1893.04M103
707' Auxiliary: RCIC Pump Room Prefire Plan
5a
1893.04M370
25' Control Building Control Room HVAC
Fire Area / Fire Zone: CB-1i
7b
Fire Plans
1893.04M730
777', 781' & 783' Turbine Building General Access &
Mezzanine
Fire Area / Fire Zone: T-1(h, k)
5d
Miscellaneous
TQ-AA-150-F25
LORT Annual Exam Status Report
2/05/2025
71111.11Q Miscellaneous
LOR Exam
Licensed Operator Requalification Exams
10/06/2025
RFP A Ovation Points Not Indicating Correctly
10/06/2025
RFP B Ovation Points Not Indicating Correctly
10/07/2025
Corrective Action
Documents
Multiple Issues Placing RFP B In Service
10/31/2025
ISSUE-2021-7256
1FP50J Troubleshoot 11-20 Turbine Generator Bearing and
Underskirt
05/21/2021
ISSUE-2023-
13094
1FP092 CNMT FP Outboard Isolation LLRT Results
07/21/2023
Miscellaneous
ISSUE-2023-
1FP050 Has A Packing Leak
09/24/2023
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
18097
ISSUE-2024-0814
FP B Low Room Temperature
01/14/2024
ISSUE-2024-
18575
Fire Pump B 0FP01PB Degrading Oil Pressure Trend
11/26/2024
9071.03
Fire Protection Water System Valve Cycling-Testable Valves
9071.03C001
Fire Protection Water System Valve Cycling
Checklist-Testable Valves
CL-PRA-021.02
Clinton Power Station Fire PRA Equipment Selection
Notebook
Procedures
CPS 3213.02
Plant Fire Detection System
Install New Model LVDT on RFP A per EC 629096
11/02/2022
Issues Identified During RFP A SPC 2 Calibration
03/29/2022
Work Orders
Replace Servo Valve on FW Reg Valve (1FW01KA)
07/30/2020
04897507
1FP050 and 1FP092 LLRT Results per 9861.02D045
09/12/2025
04897584
1WX020 As-Found Leakage Outside Admin Limit
09/13/2025
04899315
9861.02D045, FP to CNMT, 1FP092 Above Evaluation Limit
09/20/2025
04908072
1TGCV3 Actuator Cylinder Blown Seal and Indicator Damage
10/22/2025
04910320
Residual EHC Fluid Identified at Turbine Control Valve 1
10/30/2025
04910325
Leak Identified at Turbine Control Valve 3
10/30/2025
04954031
Install New Model LVDT on TDRFP-A Per EC 629096
09/21/2019
Corrective Action
Documents
Observations of TDRFP B Tuning/Calibration on SPBSPC2
10/10/2019
Drawings
M05-1089
Radwaste Sludge Process (WX)
Miscellaneous
PMC-24-149999
Revise PMID 00158129-10 Replace Servo Valve (SVA2) on
1FW01KB from an O3 to O4 Frequency
07/16/2024
3103.01
3103.02
Digital Feedwater (Ovation) System Operations
Preventive Maintenance Program
Procedures
Preventive Maintenance Oversight Committee
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Maintenance Strategy Analysis
PCM Templates
Issue Identification
and Screening
Process
Nuclear Risk
Management
Process
SM-AA-3019
Parts Quality Initiative (PQI)
Preventive Maintenance Database Revision Requirements
Self-Assessments 04908061-26
CAPE - Manual Scram Due to Main EHC Leak
10/22/2025
01149908
Replace Servo Valve (SVA2) on 1FW01KA
01/12/2010
01685570
Replace Servo Valve (SVA2) on 1FW01KA
05/04/2015
04667653
1TGCV3 Replace
01/19/2018
04968764
Issues Identified During TDRFP-A SPC 2 Calibration
10/13/2019
04996991
Replace Servo Valve (SVA2) on 1FW01KA
07/30/2020
226078
1FW01KA Replace Filter Element in Hydraulic System
09/18/2023
Work Orders
05615967
1WX020 Failed To Open - BWRT Overflowing to RF
04900136
MSIV Stem Assemblies Need Rebuilt Prior to C1R23
09/23/2025
04900157
Secondary Containment Bypass Leakage Above TS Limit
09/24/2025
04900293
C1R22 LL: Suppression Pool Level Suspect Readings
09/24/2025
04900403
C1R22 1E51F076 Overthrust
09/24/2025
Corrective Action
Documents
04900454
Leak in Drywell from 1B21F051D
09/25/2025
Miscellaneous
C1R22 SSMP
C1R22 Shutdown Safety Management Program
CPS 3005.01F001
Unit Power Changes Power Increase Flowchart
CPS 3005.01F002
Unit Power Changes Power Decrease Flowchart
CPS 3005.01F003
Secondary Thermal Power Validation
0b
Procedures
CPS 3006.01
Unit Shutdown
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
CPS 3006.01F001
Unit Shutdown Flowchart
0a
04009845
PSU: C1R17 MSIV LLRT Tech Spec 3.6.1.3 Limit Exceeded
05/12/2017
04896157
MSIV LLRT 9861.04 Acceptance Criteria not Met
09/09/2025
04897000
MSIV LLRT Leakage Determination
09/12/2025
04900160
9861.04 MSIV LLRT Final Results
09/24/2025
1C11F010 Failed to Indicate Full Closed
10/01/2025
Corrective Action
Documents
1C11F010 Internal Mechanical Binding
09/26/2025
Drawings
E02-1AP03
Electrical Loading Diagram Clinton Power Station Unit
11/09/2025
Miscellaneous
Risk Assessment:
CPS-1-2025-0329
Simple Issue Risk Assessment: C1R22 MSIV Decision and
Impact
9012.01 Rev 032
Scram Discharge Volume Vent and Drain Valve
Operability Test
04/15/2025
9012.01 Rev 032
Scram Discharge Volume Vent and Drain Valve
Operability Test
07/18/2025
Procedures
9080.21
Diesel Generator 1A - ECCS Integrated
04874764, Blank
RAT B Inspections Work Instructions
Work Orders
05449881
9080.21R20 OP *DG 1A Integrated Test
09/25/2025
EOP/SAG Guidelines for CPS
2b
Evaluation No.: 24-
§50.54(q) Program Evaluation Assessment Review for
Standardized Radiological Emergency Plan Revision 34
2/28/2025
Calculations
Evaluation No.: 25-
§50.54(q) Program Evaluation Assessment Review for Clinton
Minimum Steam Cooling RPV Level EAL
09/18/2025
Miscellaneous
EPID L-2018-LLA-
0045
Issuance of Amendments to Revise the Emergency Response
Organization Staffing Requirements
03/21/2019
Procedures
Exelon Nuclear Standardized Radiological Emergency Plan
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Standardized Radiological Emergency Plan
Addendum 3
Constellation Emergency Action Levels for Clinton Station
EPA-400/R-17/001 PAG Manual: Protective Action Guides and Planning
Guidance for Radiological Incidents
01/2017
Procedures
Addendum 3
Emergency Action Levels for Clinton Station
Breaker Tripped and Wont Reset for RAT MSC Yard Lighting
08/04/2025
Received 5008-5L due to ERAT LTC Tapping
08/15/2025
RCIC Level Switch Wiring
09/21/2025
RCIC Turb Trip As-Found Wiring Incorrect
09/21/2025
C1R22 1E51F076 Overthrust
09/25/2025
09/28/2025
RAT MSC Tripped Again During CB Pump Start
10/02/2025
RAT MSC Breaker 52-2 SF6 Pressure Was Below the
Fill Spec
10/16/2025
10/23/2025
Corrective Action
Documents
RAT B SVC Long Term Abandonment
03/12/2024
Work Orders
RCIC Steam Supply LLRT Higher than Admin Limit
09/28/2025
FP Program Health Yellow Cornerstone/White Overall 2025P1 07/22/2025
Corrective Action
Documents
Results of Clinton 2025 Biennial Fleet Safety Culture SA
07/23/2025
07/25/2025
1H2025 Station Trending HURB Documentation Review
07/25/2025
CPS Is One Component Failure Away from Required
Shutdown
07/13/2025
MOVs Improperly Descoped from C1R22
07/16/2025
Multiple FP Device Troubles Received after 22-01
07/20/2025
Fire Plans
C1R22 FAC Component 1B21-F010B Low Wall Thickness
09/20/2025