ML25119A129
| ML25119A129 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 04/29/2025 |
| From: | Kimberly Green Plant Licensing Branch II |
| To: | Hughes S Tennessee Valley Authority |
| Green K | |
| References | |
| EPID L-2024-LLA-0081 | |
| Download: ML25119A129 (3) | |
Text
From:
Kimberly Green To:
Hughes, Shawna Marie
Subject:
Request for Additional Information -TVA Alternative Request to Extend Watts Bar, Unit 2, Containment Inservice Inspection Interval (EPID L-2024-LLR-0081)
Date:
Tuesday, April 29, 2025 8:52:00 AM Attachments:
WBN2 CISI Extension Alternative Request - Final RAI.docx
Dear Shawna Hughes:
By letter dated December 12, 2025 (Agencywide Documents Access and Management System Accession No. ML24347A035), Tennessee Valley Authority (TVA) requested an alternative (i.e., WBN-2-ISI-02) from the requirements of paragraph 50.55a(g)(4)(ii) of Title 10 of the Code of Federal Regulations and certain requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessl Code for Watts Bar Nuclear Plant, Unit 2, to align the Containment Inservice Inspection Program interval end date with the TVA fleet interval end dates.
The U.S. Nuclear Regulatory Commission (NRC) staff is reviewing TVAs request and has identified an area where additional information is needed to complete its review. A draft request for additional information (RAI) was previously sent to you via email on April 24, 2025. You have indicated that the TVA does not need a clarification call. Therefore, the final RAI is unchanged from the draft RAI.
A response to the attached RAI is requested within 30 days of the date of this email. The NRC staff considers that timely responses to RAIs help ensure sufficient time is available for staff review and contribute toward the NRCs goal of efficient and effective use of staff resources. If circumstances result in the need to revise the requested response date, please me at (301)415-1627 or via email atKimberly.Green@nrc.gov.
Sincerely, Kimberly Green Senior Project Manager Division of Operating Reactor Licensing U.S. Nuclear Regulatory Commission 301-415-1627
REQUEST FOR ADDITIONAL INFORMATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION ALTERNATIVE REQUEST TO EXTEND CONTAINMENT INSERVICE INSPECTION PROGRAM INTERVAL END DATE TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT, UNIT 2 DOCKET NO. 50-391
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Introduction:==
By letter dated December 12, 2025 (Agencywide Documents Access and Management System Accession No. ML24347A035), Tennessee Valley Authority (TVA or the licensee) requested an alternative from the requirements of paragraph 50.55a(g)(4)(ii) of Title 10 of the Code of Federal Regulations (10 CFR) for Watts Bar Nuclear Plant (WBN), Unit 2, to align the Containment Inservice Inspection Program interval end date with the TVA fleet interval end dates.
Background:
The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code),Section XI, Table IWE-2500-1 (E-G), Examination Category E-G, Pressure Retaining Bolting, 2013 Edition, requires 100 percent of each Item E8.10, Bolted Connections to be examined during the first and successive inspection intervals. Note (2) states that [e]xamination may be performed with the connection assembled and bolting in place under tension, provided the connection is not disassembled during the interval. If the bolted connection is disassembled for any reason during the interval, the examination shall be performed with the connection disassembled.
Section VI, Proposed Alternative and Basis for Use in the Enclosure of Proposed Alternative WBN-2-ISI-02 states, There are two refueling outages (Cycle 7 and Cycle 8) for WBN Unit 2 that are scheduled to occur between October 18, 2026, and September 8, 2028. This change adds a fourth period (extension period) with these dates to ensure that the structural integrity of the steel containment vessel is monitored and maintained. For Examination Category E-G, Item E8.10,Section VI of Proposed Alternative WBN-2-ISI-02 states that [f]or bolted connections, 100 percent of the examination requirements will be completed by the end of the originally scheduled interval for Unit 2. However, any bolted connections that are disassembled during this timeframe, and were not previously examined in the disassembled condition, will be VT-1 examined in the disassembled condition during the extension period.
Regulatory Basis:
Section 50.55a(g)(4)(ii) of 10 CFR requires inservice examination of components and system pressure tests conducted during successive 120-month inspection intervals to comply with the requirements of the latest edition and addenda of the ASME Code incorporated by reference in paragraph (a) of 10 CFR 50.55a 18 months before the start of the 120-month inspection interval.
Paragraph 50.55a(z)(1) of 10 CFR requires the applicant to demonstrate that, when alternatives to the requirements of paragraphs (b) through (h) of 10 CFR 50.55a or portions thereof are used, the proposed alternative would provide an acceptable level of quality and safety.
Issue:
Proposed Alternative WBN-2-ISI-02 lacks information regarding how the proposed examinations of bolted connections at WBN, Unit 2, during the extension period will provide an acceptable level of quality and safety.
Request:
- 1. Summarize the examination results, conclusions, and disposition of non-conformances for bolted connections at WBN, Unit 2, that have been completed during the initial interval.
- 2. Provide the justification for why the proposed examinations on bolted connections at WBN, Unit 2, during the proposed extension period will demonstrate an acceptable level of quality and safety.