RA-24-0103, Response to Request for Additional Information (RAI) Regarding License Amendment Request for a One-Time Extension to the Integrated Leak Rate Test Interval
| ML24110A112 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/19/2024 |
| From: | Snider S Duke Energy Carolinas |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| RA-24-0103 | |
| Download: ML24110A112 (1) | |
Text
Steven M. Snider Vice President Oconee Nuclear Station Duke Energy ON01VP l 7800 Rochester Hwy Seneca, SC 29672 o: 864.873.3478 f: 864.873.5791 Steve.Snider@duke-energy.com 10 CFR 50.90 RA-24-0103 April 19, 2024 ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 Duke Energy Carolinas, LLC Oconee Nuclear Station (ONS), Units 1, 2, and 3 Docket Numbers 50-269, 50-270, and 50-287 Renewed Facility Operating License Nos. DPR-38, DPR-47, and DPR-55
Subject:
Response to Request for Additional Information (RAI) Regarding License Amendment Request for a One-Time Extension to the Oconee Units 1, 2, and 3 Integrated Leak Rate Test Interval By letter dated November 16, 2023 (Agencywide Document Access and Management System (ADAMS) Accession No. ML23320A111), Duke Energy Carolinas, LLC (Duke Energy),
submitted a license amendment request (LAR) for Oconee Nuclear Station (ONS) Units 1, 2, and 3. The proposed change would allow for a one-time extension to the ten-year frequency of the ONS Units 1, 2 and 3 containment leakage rate test (i.e., Integrated Leak Rate Test (ILRT) or Type A test). This test is required by ONS Technical Specification (TS) 5.5.2, Containment Leakage Rate Testing Program. The proposed change would permit the existing ILRT frequency to be extended from 10 years to approximately 12 years for all three ONS units.
The U.S. Nuclear Regulatory Commission (NRC) staff reviewed the LAR and determined that additional information is needed to complete their review. Duke Energy received the request for additional information (RAI) from the NRC through electronic mail on March 26, 2024 (ADAMS Accession No. ML24086A377).
The enclosure provides Duke Energys response to the RAI questions. The information contained within this response does not change the No Significant Hazards Consideration provided in the original LAR submittal.
No regulatory commitments are contained in this submittal.
If there are any questions or if additional information is needed, please contact Mr. Ryan Treadway, Director - Nuclear Fleet Licensing at 980-373-5873.
RA-24-0103 Page 2 I declare under penalty of perjury that the foregoing is true and correct. Executed on April
, 2024.
Sincerely, Steven M. Snider Vice President Oconee Nuclear Station
Enclosure:
Response to Request for Additional Information
RA-24-0103 Page 3 cc w/
Enclosure:
Ms. Laura Dudes, Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, GA 30303-1257 Mr. Shawn Williams, Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, Maryland 20852 Mr. Jared Nadel NRC Senior Resident Inspector Oconee Nuclear Station Lynne Garner Manager, Radioactive and Infectious Waste Management Section Division of Waste Management South Carolina Department of Health & Environmental Control 2600 Bull Street Columbia, SC 29201 Robin Mack Assistant Bureau Chief, Bureau of Environmental Health Services South Carolina Department of Health & Environmental Control 2600 Bull Street Columbia, SC 29201
RA-24-0103 Enclosure Page 1 of 4 ENCLOSURE RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION
RA-24-0103 Enclosure Page 2 of 4 NOTE: The U.S. Nuclear Regulatory Commission (NRC) staffs RAI questions (including the introductory discussion) are in italics throughout this enclosure to distinguish from the Duke Energy Carolinas, LLC (Duke Energy) responses.
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Background===
By letter dated November 16, 2023 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23320A111), Duke Energy Carolinas, LLC, (the licensee, Duke Energy) submitted a license amendment to revise Technical Specifications (TS) for Oconee Nuclear Station, Units 1, 2, and 3 (ONS). Specifically, the proposed change revises TS 5.5.2, Containment Leakage Rate Testing Program, by allowing a one-time extension to the ten-year frequency of the containment integrated leakage rate test (ILRT or Type A test). The proposed amendment would permit the existing ILRT frequency to be extended from 10 years to approximately 12 years for all three Oconee Units.
Regulatory Basis The U.S. Nuclear Regulatory Commission (NRC) regulations in Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Section 55a, Codes and standards, paragraph (f)(4), Inservice testing standards requirement for operating plants, state, in part, that throughout the service life of a boiling or pressurized water-cooled nuclear power facility, pumps and valves that are within the scope of the American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants, Division 1, OM Code: Section IST (OM Code) must meet the in-service test (IST) requirements (except design and access provisions) set forth in the ASME OM Code and addenda that become effective subsequent to editions and addenda specified in paragraphs 10 CFR 50.55a(f)(2) and (3) and that are incorporated by reference in paragraph 10 CFR 50.55a(a)(1)(iv), to the extent practical within the limitations of design, geometry, and materials of construction of the components.
The NRC regulations in 10 CFR Part 50, Section 54, Conditions of licenses, paragraph (o,)
require primary reactor containments for water-cooled power reactors to be subject to the requirements of 10 CFR Part 50, Appendix J, Leakage Rate Testing of Containment of Water-Cooled Nuclear Power Plants. Appendix J to 10 CFR Part 50 specifies containment leakage testing requirements, including the types required to ensure the leak-tight integrity of the primary reactor containment and systems and components which penetrate the containment. In addition, Appendix J to 10 CFR Part 50 discusses leakage rate acceptance criteria, test methodology, frequency of testing and reporting requirements for each type of test.
The NRC regulations in 10 CFR 50, Appendix J, Option B, requires a general visual inspection of the containment prior to each Type A test and at a periodic interval between tests. Nuclear Energy Institute (NEI) 94-01, Revision 3-A, recommends these inspections be performed in conjunction with the ASME Code,Section XI, Subsection IWE required examinations.
The NRC regulations in 10 CFR 50.55a(b)(2)(ix)(A) imposes a condition on the use of ASME Code,Section XI, Subsection IWE which requires licensees to evaluate the acceptability of inaccessible metal containment areas when conditions exist in accessible areas that could indicate the presence of, or result in degradation to, such inaccessible areas.
Section XI of ASME Code, Item E1.11, in Table IWE-2500-1 (E-A), requires general visual examination of 100 percent of accessible surface areas during each inspection period, while
RA-24-0103 Enclosure Page 3 of 4 Item E1.30 in the same table requires general visual examination of 100 percent of accessible moisture barriers during each inspection period.
RAI No. 1
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Background===
In Section 3.1.2, Containment Isolation System, of its LAR, the licensee describes the types of fluid penetrations which require isolation after an accident at ONS. In the subsection titled Periodic Operability Tests, the licensee states that each containment isolation valve will be tested periodically during normal operation or during shutdown conditions to assure its operability when needed. In addition, the licensee states that a program of testing and surveillance of each of the three Reactor Buildings has been developed to provide assurance, during service, of the capability of each containment system to perform its intended safety function. The NRC regulations require the licensee to implement the AMSE OM Code as incorporated by reference in 10 CFR 50.55a for the IST Program to assess the operational readiness of specific pumps, valves, and dynamic restraints at ONS.
Request for Additional Information Please describe any changes to the IST Program at ONS, including testing of containment isolation valves, that will be implemented as part of the LAR to revise TS 5.5.2 for a one-time extension of the containment Type A leak rate test frequency at ONS. If any IST Program changes are planned that would not meet the NRC regulatory requirements in the ASME OM Code as incorporated by reference in 10 CFR 50.55a, the licensee should submit requests for those changes in accordance with the NRC regulations.
Duke Energy Response to RAI No. 1 No changes to the IST Program at ONS will be implemented as a result of this proposed change to revise TS 5.5.2 for a one-time extension of the containment Type A leak rate test frequency.
RAI No. 2
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Background===
Enclosure to the LAR, Section 3.3.3 Results of Recent Containment Examinations, Part Oconee Unit 2 2019 Moisture Barrier Inspection, (page 106 of 185) identified 9 non-conforming conditions during the examination of the moisture barrier.
Issue The non-conforming conditions on page 106 of the enclosure states the moisture barrier is missing, cracked, has separated from the wall, or contain holes; however, insufficient discussion is provided about the condition of the containment liner behind the non-conforming moisture barrier. A degraded moisture barrier could indicate the presence of degradation in the inaccessible areas behind the moisture barrier. Furthermore, a degraded moisture barrier could allow moisture to contact the containment and cause degradation in an inaccessible area.
RA-24-0103 Enclosure Page 4 of 4 Requests for Additional Information
- 1. Summarize the results of any 10 CFR 50.55a(b)(2)(ix)(A) evaluations associated with the noted non-conforming moisture barrier conditions or explain how it was determined that the inaccessible portions of the containment were not impacted and that an evaluation was not necessary.
- 2. Provide a description of the corrective actions taken or engineering evaluation for the non-conforming moisture barrier defects that were identified (missing, cracked, separated from the wall, and holes).
Duke Energy Response to RAI No. 2
- 1. During refueling outage O2R29 (Fall, 2019), periodic visual examinations of all moisture barriers within containment were performed in accordance with ASME Section XI requirements (Reference 1). The examination of the moisture barrier was to identify any unacceptable defects that would permit intrusion of moisture against inaccessible areas of pressure retaining surfaces of the metallic containment liner. These visual examinations revealed several areas of the degradation and delamination between the moisture barrier and the containment liner. Per IWE-3512, degraded moisture barriers that could permit intrusion of moisture against inaccessible surfaces of the metallic containment liner shall be corrected by corrective measures. Therefore, all identified areas with degradation or delamination were replaced with new moisture barriers and reinspected in accordance with ASME Section XI, Section IWE-3122.2 during O2R29. When the old moisture barrier was removed, the liner behind the moisture barrier was made accessible for VT-1 examination. A VT-1 examination of the exposed metallic containment liner was performed and revealed no corrosion or relevant conditions. Afterwards, the moisture barrier was replaced, and a preservice VT-1 exam of the replaced moisture barrier was performed. Therefore, since all the metallic containment liner located behind degraded moisture barriers was examined and no relevant conditions were identified, evaluations associated with inaccessible portions of containment were not required.
- 2. Prior to completing outage O2R29, corrective measures in compliance with IWE-3122.2 were performed on all degraded moisture barriers identified during the IWE visual examinations.
Specifically, all degraded/delaminated moisture barriers identified were completely removed allowing accessibility to perform a VT-1 exam of the exposed metallic containment liner.
These VT-1 exams revealed no corrosion or relevant conditions associated with the metallic containment liner. As needed, touch-up coatings were applied to the metallic containment liner in accordance with site coatings maintenance requirements. Following these metallic liner coating repairs, a new moisture barrier was installed between the liner and concrete basement floor. A preservice VT-1 of the newly replaced moisture barrier was performed prior to continued service. Subsequent periodic examinations of all moisture barriers are performed in accordance with ASME Section XI, Subsection IWE as scheduled in the ONS Containment IWE Inservice Inspection Plan and Schedule document.
RAI No. 2 References
- 1. American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code)
Section XI, 2007 Edition with the 2008 Addenda.