ML25303A001
| ML25303A001 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 10/29/2025 |
| From: | Chatman C Dominion Energy Nuclear Connecticut |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| Download: ML25303A001 (1) | |
Text
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station 314 Rope Ferry Road, Waterford, CT 06385 Dominion Energy.com U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 October 29, 2025 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3 Serial No.25-225 NSSL/TFO RO Docket No.
50-423 License No. NPF-49 INSERVICE INSPECTION PROGRAM -
OWNER'S ACTIVITY
- REPORT, REFUELING OUTAGE 23 Dominion Energy Nuclear Connecticut, Inc. (DENG) hereby submits the American Society of Mechanical Engineers (ASME),Section XI, Form OAR-1, Owner's Activity Report, for the period from December 1, 2023, through Refueling Outage 23, completed on May 18, 2025, for Millstone Power Station Unit 3. The enclosure is in accordance with the requirements of ASME Code Case N-532-5.
If you have any questions or require additional information, please contact Ms. Lori K. Kelley at (860) 447-1791, extension 6520.
Christopher S. Chatman Director, Plant Support - Millstone
Enclosure:
- 1. Millstone Power Station Unit 3 Owner's Activity Report, Refueling Outage 23, Report Number MP3-3R23.
Commitments made in this letter: None
cc:
U. S. Nuclear Regulatory Commission Region I 475 Allendale Road, Suite 102 King of Prussia, PA 19406-1415 Theo L. Edwards Project Manager U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop O-8C04 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station Serial No.25-225 MPS3 Owner's Activity Report Docket No. 50-423 Page 2 of 2
ENCLOSURE 1 MILLSTONE POWER STATION UNIT 3 OWNER'S ACTIVITY REPORT REFUELING OUTAGE 23 REPORT NUMBER MP3-3R23 Serial No.25-225 Docket No. 50-423 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3
Form OAR-1 Owner's Activity Report I ER-AA-ISI-100 ATTACHMENT 1 Page 1 of 3 Report Numb er:
MP3-3R23 Plant: Millstone Nuclear Power Station. Rope FerN Road, Waterford. Connecticut 06385 Unit No.
3 Commercial service date: April 26, 1986 Refueling outage no. 23 (if applicable)
Current inspection interval: --------'4-=th-=---------
(1st, 2nd, 3rd, 4th, other)
Current inspection period: ----~2=n~dc.--__________ _
(1st, 2nd 1 3rd)
Edition and Addenda of Section XI applicable to the inspection plans:
2013 Edition, No Addenda Date and revision of inspection p I ans: ---=-08=/-=0-=8/=2=0=22=---/.:...R=e..... v*=,s=io;..:..n....,2=----------------
Edition and Addenda of Section XI applicable to repair/replacement activities, if different than the inspection plans:
N/A Code Cases used for inspection and evaluation:
N-532-5. N-716-1. N-722-1. N-729-6, N-800. N-831-1. N-892 (if applicable, including cases modified by Case N-532 and later revisions)
CERTIFICATE OF CONFORMANCE I certify that (a) the statements made in this report are correct; (b) the examinations and tests meet the Inspection Plan as required bythe ASME Code,Section XI; and (c) the repair/replacement activities and evaluations supporting the completion of 3R23 conform to the requirements of Section XI.
(refueling o CERTIFICATE OF INSERVICE INSPECTION I, the undersigned, holding a valid commission issued by the National Board of Boiler and Pressure Vessel Inspectors and employed by Hartford Steam Boiler Inspection and Insurance Company of Hartford. CT have inspected the items described in this Owner's Activity Report, and state that, to the best of my knowledge and belief, the Owner has performed all activities represented by this report in accordance with the requirements of Section XI.
By signing this certificate neither the Inspector nor his employer makes any warranty, expressed or implied, concerning the repair/replacement activities and evaluation described in this report. Furthermore, neither the Inspector nor his employer shall be liable in any mannerforany personal injury or property damage, ora loss of any kind arising from or connected with this i spection.
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National Board Number and Endorsement Form No. 729595 (Apr 2021)
Form OAR-1 Owner's Activity Report I ER-AA-ISI-100 ATTACHMENT 1 Page 2 of 3 Table 1 Items with Flaws or Relevant Conditions That Required Evaluation for Continued Service Examination Category and Item Number Item Description Evaluation Description Bolting less than full thread Pipe Support engagement. Evaluated by F-A/F1.10B 3-RCS-1-PSR431 Engineering and found to be acceptable for continued service.
Reference CR1289011 Support spring load setting found to be out of design tolerance.
F-A/F1.20C Pipe Support Evaluated by Engineering and 3-S IL-1-P SS H033 found to be acceptable for continued service.
Reference CR1288725 Service Water pump strainer shell wall thickness was found to be below the design required thickness. Engineering has evaluated this condition for structural integrity in accordance with ASME Section XI, Non-N/A Service Water Pump Strainer Mandatory Appendix U and found 3SWP*STR1B to be acceptable for continued service until repair could be completed. Reference CR1250708, CR1251354 and ETE-MP-2024-1011. Repair was completed on 05/01/2025 under work order 53203410397.
Form No. 729595 (Apr 2021)
Form OAR-1 Owner's Activity Report I ER-AA-ISI-100 ATTACHMENT 1 Page 3 of 3 Table 2 Abstract of Repair/Replacement Activities Required for Continued Service Code Item Description Description of Work Date Repair/Replacement Class Completed Plan Number Service Water Perform weld repair on U3-2645 3
system piping piece 4/27/2025 (53203455013) 3SWP-21-8, degraded area No. 1 Service Water Perform weld repair on U3-2644 3
system piping piece 4/27/2025 (53203455012) 3SWP-21-8 degraded area No. 2 Service Water Perform weld repair on U3-2642 3
system piping piece 4/27/2025 (53203454371) 3SWP-21-7A, degraded pipe flange.
Service Water Perform weld repair on U3-2636 3
pump strainer 5/01/2025 (53203410397) 3SWP*STR1B strainer shell assembly.
Installation of Service Water system piping blind Blind Flange was 3
flange that did not removed, and system 4/17/2025 U3-2658 comply with ASME was restored to required (53203438698)
Section XI & Ill design configuration.
requirements.
(CR1301260)
Form No. 729595 (Apr 2021)