ML25262A005
| ML25262A005 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 09/30/2025 |
| From: | Geoffrey Miller Plant Licensing Branch II |
| To: | Carr E Dominion Energy |
| Miller G | |
| References | |
| EPID L-2025-LLL-0016 | |
| Download: ML25262A005 (1) | |
Text
September 30, 2025 Mr. Eric S. Carr Senior Vice President and Chief Nuclear Officer Innsbrook Technical Center 5000 Dominion Blvd.
Glen Allen, VA 23060-6711
SUBJECT:
NORTH ANNA POWER STATION, UNIT NO. 1 - RE: REQUEST TO REVISE REACTOR VESSEL MATERIAL SURVEILLANCE CAPSULE WITHDRAWAL SCHEDULE (EPID L-2025-LLL-0016)
Dear Mr. Carr:
By letter dated September 23, 2025 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25267A090), Virginia Electric Power Company (VEPCO, Dominion Energy Virginia) requested approval to revise the reactor vessel materials surveillance capsule withdrawal schedules for North Anna Power Station, Unit 1.
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the subject request and concludes, as set forth in the enclosed safety evaluation, that VEPCO has demonstrated that the proposed schedule revision remains consistent with the intent and requirements found in Appendix H to Title 10 of the Code of Federal Regulations (10 CFR), Part 50. Therefore, the NRC staff approves the requested change.
If you have any questions, please contact the Project Manager, Ed Miller at (301) 415-2481 or via e-mail at Ed.Miller@nrc.gov.
Sincerely, Michael T. Markley, Chief Plant Licensing Branch 2-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-338
Enclosure:
Safety Evaluation cc: Listserv MICHAEL MARKLEY Digitally signed by MICHAEL MARKLEY Date: 2025.09.30 06:47:42 -04'00'
Enclosure SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REVISION TO REACTOR VESSEL MATERIALS SURVEILLANCE CAPSULE WITHDRAWAL SCHEDULE VIRGINIA ELECTRIC POWER COMPANY NORTH ANNA POWER STATION, UNIT NOS. 1 DOCKET NO. 50-338
1.0 INTRODUCTION
By letter dated September 23, 2025 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25267A090), Virginia Electric and Power Company (Dominion Energy Virginia or Dominion, the licensee) requested revision of the reactor vessel material surveillance capsule withdrawal schedule for North Anna Power Station (North Anna), Unit 1.
In accordance with Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix H, Reactor Vessel Material Surveillance Program Requirements,Section III.B.3, a proposed withdrawal schedule must be submitted with a technical justification as specified in § 50.4 and must be approved prior to implementation. Specifically, the licensee proposed to revise the reactor vessel material surveillance capsule withdrawal schedule so that Capsule X is removed from the reactor vessel after 41.9 effective full power year (EFPY) of operation such that it is exposed to a neutron fluence of 7.69 x 1019 neutron per square centimeter (n/cm2).
2.0 REGULATORY EVALUATION
The regulations and guidance pertinent to this request include:
Section I of Appendix H to 10 CFR Part 50 states, in part, that:
The purpose of the [reactor vessel] material surveillance program required by this appendix is to monitor changes in the fracture toughness properties of ferritic materials in the reactor vessel beltline region of light water nuclear power reactors which result from exposure of these materials to neutron irradiation and the thermal environment. Under the program, fracture toughness test data are obtained from material specimens exposed in surveillance capsules, which are withdrawn periodically from the reactor vessel.
Section III(B)(3) of Appendix H to 10 CFR Part 50 states:
A proposed withdrawal schedule must be submitted with a technical justification as specified in [10 CFR 50.4]. The proposed schedule must be approved prior to implementation.
Generic Letter 97-04, NRC [U.S. Nuclear Regulatory Commission] Staff Approval for Changes to 10 CFR Part 50, Appendix H, Reactor Vessel Surveillance Specimen Withdrawal Schedules, dated September 30, 1997 (ML031210296), states, in part:
The Commission found that while 10 CFR Part 50, Appendix H, II.B.3 requires prior NRC approval for all withdrawal schedule changes, only certain changes require license amendments as the process to be followed for such approval.
Specifically, those changes that do not conform to the ASTM standard referenced in Appendix H (ASTM E-185, Standard Practice for Conducting Surveillance Tests for Light-Water Cooled Nuclear Power Reactor Vessels) will require approval by the license amendment process, whereas changes that conform to the ASTM standard require only staff verification of such conformance.
NUREG-2191, Revision 1, Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report, July 2025.
3.0 TECHNICAL EVALUATION
3.1 Fluence Analysis The licensee has not proposed any changes to the fluence model that was previously approved by the NRC staff on August 6, 2020 (ML20216A299). Therefore, no further review of this aspect is necessary.
3.2 Surveillance Capsule Withdrawal Schedule Change By letter dated August 24, 2020 (ML20246G696 and ML20246G698), the licensee submitted application for the subsequent license renewal for North Anna, Units 1 and 2, pursuant to 10 CFR Part 54. The NRC staff issued the Safety Evaluation Related to the Subsequent License Renewal of North Anna Power Station, Units 1 and 2, on January 4, 2022 (ML21354A196).
Table 5.4-2 of the North Anna, Unit 1, Updated Final Safety Analysis Report (UFSAR) indicates that the projected 80-year peak neutron fluence at clad-base metal interface of the reactor vessel is 7.20 x 1019 n/cm2. Table 5.4-2 further indicated that the schedule for the withdrawal of Capsule X was estimated at 39.1 EFPY (2025).
During the current refueling outage (North Anna, Unit 1, Thirty-First Refueling Outage [1R31]),
the licensee attempted to withdraw Capsule X, as scheduled. Despite repeated attempts, the licensee was unable to withdraw Capsule X using the Irradiated Sample Handling Tool (ISHT).
The licensee determined that additional attempts using increasing levels of force to the ISHT would likely result in damage to the ISHT and the possible introduction of debris into the reactor vessel. Therefore, the licensee proposed revision of the reactor vessel material surveillance capsule withdrawal schedule, delaying the withdrawal of Capsule X to the NAPS, Unit 1, Thirty-Third Refueling Outage (1R33) in 2028, during which the core barrel lift will allow for improved access to the capsule. The projected neutron fluence at Refueling Outage 1R33 at 41.9 EFPY is 7.69 x 1019 n/cm2.
The NRC staff finds that the licensees proposal to withdraw Capsule X after 41.9 EFPY of operation in order for the capsule to be exposed to a neutron fluence of 7.69 x 1019 n/cm2 would achieve the same objective for this capsule as contained in the schedule in the licensees current licensing basis, which is explained in the Safety Evaluation Report Related to the Subsequent License Renewal of North Anna Power Station, Units 1 and 2 (ML21354A196).
Additionally, the NRC staff notes that the proposed schedule for the Capsule X is also consistent with the guidelines in the American Society for Testing of Materials (ASTM) E185-82 for the end of license (EOL) capsule, which is to be withdrawn at not less than once or greater than twice the peak end-of-life vessel neutron fluence.
The NRC staff noted that NUREG-2191, Revision 1, Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report, provides the NRC staffs recommendation of aging management programs that the staff determined are adequate for the subsequent period of extended operation. Specifically, NUREG-2191,Section XI.M31, Reactor Vessel Material Surveillance, recommends that this program includes withdrawal and testing of at least one capsule addressing the subsequent period of extended operation with a neutron fluence of the capsule between one and two times the peak neutron fluence of interest at the end of the subsequent period of extended operation. North Anna, Unit 1, Subsequent License Renewal Application Section 4.2, Reactor Vessel Embrittlement Analysis, indicates that the 72 EFPY bounding peak neutron fluence at clad-base metal interface of the reactor vessel is 7.20 x 1019 n/cm2. The NRC staff noted that the proposed withdrawal of the Capsule X after 72 EFPY of operation in order for the capsule to be exposed to a neutron fluence of 7.20 x 1019 n/cm2 achieves at least one time but not exceeding two times the maximum neutron fluence projections for 80 years of operation.
The NRC staff determined that the proposed withdrawal schedule for North Anna, Unit 1, Capsule X will accomplish addressing (1) the underlying purpose for Appendix H to 10 CFR Part 50 (i.e., monitor changes in the fracture toughness properties of the reactor pressure vessel and (2) recommendations in NUREG-2191 for the subsequent period of extended operation. Therefore, the NRC staff finds that the licensees proposed revision of the withdrawal schedule for the North Anna, Unit 1, Capsule X be tested following its withdrawal during Refueling Outage 1R33, is acceptable.
4.0 CONCLUSION
Based on the above, the NRC staff concludes that the revised surveillance capsule withdrawal schedule for North Anna, Unit 1, Capsule X to be withdrawn and tested during Refueling Outage 1R33 after 41.9 EFPY is acceptable and approves this revised surveillance capsule withdrawal schedule.
Principal Contributor: C. Fairbanks, NRR Date: September 30, 2025
ML25262A005 OFFICE NRR/DORL/LPL2-1/PM NRR/DORL/LPL2-1/LA NRR/DNRL/NVIB NAME GEMiller KZeleznock ABuford DATE 09/29/2025 09/29/2025 09/29/2025 OFFICE NRR/DORL/LPL2-1/BC NAME MMarkley DATE 9/30/2025