IR 05000336/2025004
| ML26028A066 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 01/28/2026 |
| From: | Glenn Dentel Division of Operating Reactors |
| To: | Carr E Dominion Energy |
| References | |
| IR 2025004 | |
| Download: ML26028A066 (0) | |
Text
January 28, 2026
SUBJECT:
MILLSTONE POWER STATION, UNITS 2 AND 3 - INTEGRATED INSPECTION REPORT 05000336/2025004 AND 05000423/2025004
Dear Eric Carr:
On December 31, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Millstone Power Station, Units 2 and 3. On January 21, 2026, the NRC inspectors discussed the results of this inspection with James Petty, Site Vice President, and other members of your staff. The results of this inspection are documented in the enclosed report.
No findings or violations of more than minor significance were identified during this inspection.
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, Glenn T. Dentel, Acting Chief Projects Branch 2 Division of Operating Reactor Safety
Docket Nos. 05000336 and 05000423 License Nos. DPR-65 and NPF-49
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000336 and 05000423
License Numbers:
Report Numbers:
05000336/2025004 and 05000423/2025004
Enterprise Identifier: I-2025-004-0046
Licensee:
Dominion Energy Nuclear Connecticut, Inc.
Facility:
Millstone Power Station, Units 2 and 3
Location:
Waterford, CT
Inspection Dates:
October 1, 2025 to December 31, 2025
Inspectors:
B. Pinson, Senior Resident Inspector
D. Antonangeli, Resident Inspector
E. Bousquet, Resident Inspector
T. Fish, Senior Operations Engineer
M. Patel, Senior Operations Engineer
B. Dyke, Senior Operations Engineer
N. Eckhoff, Health Physicist
E. Chen, Reactor Inspector
Approved By:
Glenn T. Dentel, Acting 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 Millstone Power Station, Units 2 and 3,
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
No findings or violations of more than minor significance were identified.
Additional Tracking Items
None.
PLANT STATUS
Unit 2 operated at or near rated thermal power for the entire inspection period.
Unit 3 began the inspection period at rated thermal power. On October 16, 2025, the unit shut
down for a planned maintenance outage to address reactor coolant pump seal leakage and
returned to rated thermal power on October 28, 2025. On November 4, 2025, the unit lowered
power to approximately 75 percent to repair a leak on the cover of service water check valve
3SWP*V705 and returned to rated thermal power on November 5, 2025. The unit 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 DProperty "Inspection Manual Chapter" (as page type) with input value "NRC Inspection Manual 2515,</br></br>Appendix D" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process., 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 evaluated the adequacy of the overall preparations to protect risk-
significant systems from impending severe weather prior to the onset of heavy rain
and wind on October 10, 2025.
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)
Unit 3, 'A' residual heat removal train during shutdown cooling operations,
October 21, 2025
(2)
Unit 3, 'B' train of service water located in the engineered safeguards building,
November 5, 2025
(3)
Unit 3, reactor plant component cooling water system components located in the
auxiliary building, December 17, 2025
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (7 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)
Unit 3, main steam valve building (fire area MSV-1 elevation 24'6", 41', 49'6", and
71'6"), October 1, 2025
(2)
Unit 3, east switchgear room (fire area CB-2 elevation 4'6"), October 2, 2025
(3)
Unit 3, normal switchgear room (fire area SB-1), November 17, 2025
(4)
Unit 2, auxiliary building railroad bay area (fire area A-14B elevation 14'6"),
November 20, 2025
(5)
Unit 3, auxiliary building (fire area AB-1C), elevation 24 foot, November 24, 2025
(6)
Unit 3, cable spreading room (fire area CB-8), November 25, 2025
(7)
Unit 2, intake structure (fire area I-1, zone A), December 11, 2025
71111.06 - Flood Protection Measures
Flooding Sample (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated internal flooding mitigation protections in the:
Unit 2, upper 4160 volt switchgear room, west cable vault, and 480 volt west
switchgear room, December 3, 2025.
71111.07A - Heat Exchanger/Sink Performance
Annual Review (IP Section 03.01) (1 Sample)
The inspectors evaluated readiness and performance of:
(1)
Unit 2 'A' reactor building component cooling water heat exchanger, including review
of eddy current testing from December 2 through December 4, 2025 (Work Order
(WO)53203406272)
71111.11A - Licensed Operator Requalification Program and Licensed Operator Performance
Requalification Examination Results (IP Section 03.03) (2 Samples)
(1)
The inspectors reviewed and evaluated the Unit 3 licensed operator examination
failure rates for the Unit 3 requalification annual operating exams administered
October - November 2025 and the Unit 3 biennial written examinations administered
November - December 2024.
(2)
The inspectors reviewed and evaluated the licensed operator examination failure
rates for the Unit 2 requalification annual operating exam completed on
December 12, 2025.
71111.11B - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Requalification Program (IP Section 03.04) (1 Sample)
(1)
Biennial Requalification Written Examinations
The inspectors evaluated the quality of the Unit 3 licensed operator biennial
requalification written examinations administered November - December 2024.
Annual Requalification Operating Tests
The inspectors evaluated the adequacy of the Unit 3 annual requalification operating
test administered week of October 28, 2025.
Administration of an Annual Requalification Operating Test
The inspectors evaluated the effectiveness of the facility licensee in administering
requalification operating tests required by Title 10 of the Code of Federal Regulations
(10 CFR) 55.59(a)(2) and that the facility licensee is effectively evaluating their
licensed operators for mastery of training objectives.
Requalification Examination Security
The inspectors evaluated the ability of the facility licensee to safeguard examination
material, such that the examination is not compromised.
Remedial Training and Re-examinations
The inspectors evaluated the effectiveness of remedial training conducted by the
licensee, and reviewed the adequacy of re-examinations for licensed operators who
did not pass a required requalification examination.
Operator License Conditions
The inspectors evaluated the licensees program for ensuring that licensed operators
meet the conditions of their licenses.
Control Room Simulator
The inspectors evaluated the adequacy of the facility licensees control room
simulator in modeling the actual plant, and for meeting the requirements contained in
71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Performance in the Actual Plant/Main Control Room (IP Section 03.01) (4 Samples)
(1)
The inspectors observed and evaluated licensed operator performance in the Unit 3
control room during solid plant operations, October 16, 2025.
(2)
The inspectors observed and evaluated licensed operator performance in the Unit 3
control room during reactor startup operations, October 26, 2025.
(3)
The inspectors observed and evaluated licensed operator performance in the Unit 3
control room during multiple diesel generators starts, as part of a maintenance
outage, during the week of November 17, 2025.
(4)
The inspectors observed and evaluated licensed operator performance in the Unit 2
control room during a period of elevated risk due to 'D' service water bay outage,
switchyard work, reactor building component cooling water heat exchanger outage,
and reactivity manipulations from December 9-10, 2025.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (4 Samples)
(1)
The inspectors observed and evaluated Unit 3 operator performance in the simulator
during just in time training for a unit shutdown, October 15, 2025.
(2)
The inspectors observed and evaluated Unit 3 operator performance in the simulator
during just in time training activities related to service water train 'A' isolation,
November 4, 2025.
(3)
The inspectors observed and evaluated operator requalification training in the Unit 2
simulator, November 4, 2025.
(4)
The inspectors observed and evaluated licensed operator requalification training in
the Unit 3 simulator, December 9, 2025.
71111.12 - Maintenance Effectiveness
Maintenance Effectiveness (IP Section 03.01) (1 Sample)
The inspectors evaluated the effectiveness of maintenance to ensure the following
structures, systems, and components (SSCs) remain capable of performing their intended
function:
(1)
Unit 3 safety-related dampers 3HVP*MOD26B, 3HVP*MOD23B, 3HVP*MOD26A,
and 3HVP*MOD23A, December 31, 2025
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)
ASME Qualifications for replacement service water valve bonnet, SWP*V705,
following emergent replacement, November 7, 2025
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (3 Samples)
The inspectors evaluated the accuracy and completeness of risk assessments for the
following planned and emergent work activities to ensure configuration changes and
appropriate work controls were addressed:
(1)
Unit 2, scheduled yellow risk due to switchyard maintenance requiring north bus
outage, October 14, 2025
(2)
Unit 3, containment closure due to a short time to boil with the reactor shutdown,
October 18, 2025
(3)
Unit 3, high risk plans in effect due to isolation of the 'A' train of service water for
replacement of a check valve bonnet at power, November 4-5, 2025
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (7 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the
following operability determinations and functionality assessments:
(1)
Unit 2, 'B' emergency diesel generator alarm response procedure entry for jacket
water low temperature along with failure of standby jacket water pump to run,
October 16, 2025
(2)
Unit 3, 'B' residual heat removal excessive seal leak, October 23, 2025 (Condition
Report (CR) 130457)
(3)
Unit 3, functionality assessment associated with leading edge flow meter degraded
transducers, November 24, 2025
(4)
Unit 2, non-vital 120 volt power supply, VR-21, to control element assembly control
board core mimic panel indication for CEA-47, December 4, 2025 (CRs 1298943,
1306753, and 1306807)
(5)
Unit 2, operability determination and engineering technical evaluation associated with
a through-wall flaw on 'A' service water header piping upstream of valve 2-SW-3.2B,
December 17, 2025 (CR 1308124)
(6)
Unit 3, steam dump isolation valves found out of position, December 19, 2025
(CR 1309651)
(7)
Unit 2, 'B' emergency diesel generator jacket water cooling system with thermal
overload discrepancy in jacket water pump motor, December 23, 2025
71111.20 - Refueling and Other Outage Activities
Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated reactor coolant pump seal replacement forced outage
activities from October 16, 2025, to October 28, 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) (8 Samples)
(1)
Unit 2, replacement of automatic control element drive mechanism (CEDM) timing
module for CEDM 68, October 3, 2025
(2)
Unit 3, repair of station blackout air valve, 3BGA-AOV84, October 6, 2025 (WO 53203468036 and CR 1302692)
(3)
Unit 2, post-maintenance testing of 'B' emergency diesel generator standby jacket
water cooling pump following thermal overload replacement, October 16, 2025 (WO 53203469358)
(4)
Unit 3, 'B' service water strainer inspection and repair, October 17, 2025 (WOs
53203469327 and 53203469499)
(5)
Unit 3, replacement of 'C' reactor coolant pump seal assembly, October 21-22, 2025
(6)
Unit 3, post-maintenance testing of the 'B' containment air recirculation fan following
replacement, October 24, 2025
(7)
Unit 3, post-maintenance operability testing of 'B' emergency diesel generator,
November 22, 2025 (WO 53203450180)
(8)
Unit 3, calibration and testing of 'B' chiller temperature switch M33HVK*TS1006B,
December 4, 2025 (WO 53203465243)
Diverse and Flexible Coping Strategies (FLEX) Testing (IP Section 03.02) (1 Sample)
(1)
Beyond design basis high capacity pumps 'A' and 'B', annual and semiannual
surveillances reviewed, December 2, 2025
71114.06 - Drill Evaluation
Additional Drill and/or Training Evolution (1 Sample)
The inspectors evaluated:
(1)
Unit 1 emergency planning drill on December 4, 2025
RADIATION SAFETY
71124.08 - Radioactive Solid Waste Processing & Radioactive Material Handling, Storage, &
Transportation
Radioactive Material Storage (IP Section 03.01) (1 Sample)
The inspectors evaluated the licensees performance in controlling, labeling, and securing
the following radioactive materials:
(1)
Radioactive materials containers in warehouse 9 and stack yard.
Radioactive Waste System Walkdown (IP Section 03.02) (1 Sample)
The inspectors walked down the following accessible portions of the solid radioactive waste
systems and evaluated system configuration and functionality:
(1)
Radioactive liquid processing system
Waste Characterization and Classification (IP Section 03.03) (2 Samples)
The inspectors evaluated the following characterization and classification of radioactive
waste:
(1)
Unit 2 2R29 dry active waste 2024, L107814-1
(2)
Unit 3 ALPS resin sample, L109562-2
Shipping Records (IP Section 03.05) (3 Samples)
The inspectors evaluated the following non-excepted radioactive material shipments through
a record review:
(1)
Shipment number 25-055, UN3321, LSA II, dry active waste
(2)
Shipment number 25-067, UN3321, LSA II, U3 Carbon/Bead ALPS Resin Liner
(3)
Shipment number 25-067, UN3321, LSA II, U3 ALPS Bead/SRT Resin Liner
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) (2 Samples)
(1)
Unit 2, July 1, 2024 through June 30, 2025
(2)
Unit 3, July 1, 2024 through June 30, 2025
MS06: Emergency AC Power Systems (IP Section 02.05) (2 Samples)
(1)
Unit 2, July 1, 2024 through June 30, 2025
(2)
Unit 3, July 1, 2024 through June 30, 2025
MS07: High Pressure Injection Systems (IP Section 02.06) (2 Samples)
(1)
Unit 2, July 1, 2024 through June 30, 2025
(2)
Unit 3, July 1, 2024 through June 30, 2025
MS08: Heat Removal Systems (IP Section 02.07) (2 Samples)
(1)
Unit 2, July 1, 2024 through June 30, 2025
(2)
Unit 3, July 1, 2024 through June 30, 2025
MS09: Residual Heat Removal Systems (IP Section 02.08) (2 Samples)
(1)
Unit 2, July 1, 2024 through June 30, 2025
(2)
Unit 3, July 1, 2024 through June 30, 2025
MS10: Cooling Water Support Systems (IP Section 02.09) (2 Samples)
(1)
Unit 2, July 1, 2024 through June 30, 2025
(2)
Unit 3, July 1, 2024 through June 30, 2025
OR01: Occupational Exposure Control Effectiveness Sample (IP Section 02.15) (1 Sample)
(1)
November 1, 2024 through November 30, 2025
PR01: Radiological Effluent Technical Specifications/Offsite Dose Calculation Manual
Radiological Effluent Occurrences (RETS/ODCM) Radiological Effluent Occurrences Sample
(IP Section 02.16) (1 Sample)
(1)
November 1, 2024 through November 30, 2025
71152A - Annual Follow-up Problem Identification and Resolution
Annual Follow-up of Selected Issues (Section 03.03) (1 Sample)
The inspectors reviewed the licensees implementation of its corrective action program
related to the following issues:
(1)
Review of recent trips of Units 2 and 3 emergency diesel generators and station
blackout diesel, December 3, 2025 (CR 12111444)
71152S - Semiannual Trend Problem Identification and Resolution
Semiannual Trend Review (Section 03.02) (2 Samples)
(1)
The inspectors reviewed the licensees corrective action program to identify potential
trends in Unit 3 alarm response procedure use and adherence that might be
indicative of a more significant safety issue.
(2)
The inspectors reviewed the licensees corrective action program to identify potential
trends in Unit 2 unplanned instrument air compressor outages that might be indicative
of a more significant safety issue.
INSPECTION RESULTS
Observation: Semiannual Trend Review
The inspectors evaluated a sample of Unit 3 control room operator log entries for unexpected
annunciator alarms that occurred from July 2025 through November 2025, to determine
whether issues were appropriately considered as emerging or adverse trends. The inspectors
verified that issues were appropriately evaluated by licensee staff for potential trends and
addressed within the scope of the corrective action program or through department review.
The inspectors did not identify any new trends that could indicate a more significant safety
issue. The inspectors determined that Millstone personnel identified trend issues at a low
threshold and entered them into the corrective action program for resolution.
The inspectors noted some instances where issues were entered into the operator logs, but
CRs were not written consistently or were not written due to prior CRs existing related to the
issue. This could have an impact on the ability to trend adverse conditions in the future if new
CRs are not being consistently written. The inspectors did not identify any instances where a
CR was not written when procedurally required. None of the reviewed issues impacted
system operability or functionality and Millstone personnel were monitoring the conditions.
The inspectors independently evaluated the deficiencies noted above for significance in
accordance with the guidance in IMC 0612, Appendix B, "Issue Screening," and Appendix E,
"Examples of Minor Issues." The inspectors determined that none of the conditions were
deficiencies of more than minor significance and, therefore, are not subject to enforcement
action in accordance with the NRC's Enforcement Policy.
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
James Petty, Site Vice President, and other members of the licensee staff.
On December 4, 2025, the inspectors presented the 71124.08 Inspection Debrief
inspection results to Mark Goolsbey, Nuclear Operations Director, and other members of
the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Corrective Action
Documents
CR 1211444
Procedures
DQR-SYS-ENG-
System/Component Engineer (Initial)
Revision 0
Work Orders
53203345034