ML21273A192
| ML21273A192 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 10/12/2021 |
| From: | Luke Haeg Plant Licensing Branch II |
| To: | |
| Wentzel M | |
| References | |
| EPID L-2021-LRM-0091 | |
| Download: ML21273A192 (4) | |
Text
October 12, 2021 LICENSEE: Tennessee Valley Authority FACILITY: Browns Ferry Nuclear Plant, Unit 2
SUBJECT:
SUMMARY
OF SEPTEMBER 27, 2021, MEETING WITH TENNESSEE VALLEY AUTHORITY RELATED TO A PLANNED ALTERNATIVE REQUEST PER AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) CODE CASE N-526, ALTERNATIVE REQUIREMENTS FOR SUCCESSIVE INSPECTIONS OF CLASS 1 AND 2 VESSELS, SECTION XI, DIVISION 1, FOR BROWNS FERRY NUCLEAR PLANT, UNIT 2 (EPID L-2021-LRM-0091)
On September 27, 2021, an Observation Public Meeting was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of the Tennessee Valley Authority (TVA, the licensee) via teleconference. The purpose of the meeting was to discuss a planned alternative request per the American Society of Mechanical Engineers (ASME) Code Case N-526 for a reactor pressure vessel subsurface flaw identified during examinations as part of the Browns Ferry, Unit 2, spring of 2021 refueling outage (RFO). The meeting notice and agenda dated September 13, 2021, are available in the Agencywide Documents Access and Management System (ADAMS) at Accession No. ML21270A049. A list of attendees is provided as an enclosure.
The licensee presented information (ADAMS Accession No. ML21270A032) regarding the reason for the planned request, the applicable ASME Code requirements, and schedule for the submittal. Specifically, the licensee proposed an alternative to the requirements of ASME Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Article IWB-2420, Successive Inspections. Namely, if a component (the reactor pressure vessel (RPV), in this case) is accepted for continued service after detection of a flaw, IWB-2420(b) requires reexamination of areas containing flaws during the next three inspection periods. Code Case N-526 provides an alternative to the successive examination requirements for subsurface flaws. The licensee discussed that although Code Case N-526 did not specifically address whether the criteria for flaw proximity applied to the inside or outside surface of the RPV, the licensees position was that the Code Case could be applied after performance of conservative calculations that considered the flaws proximity to the inside RPV surface. The licensee anticipated submittal of the request on October 27, 2021, with a requested approval date of November 4, 2022.
The NRC staff queried the licensee regarding the applicable ASME requirements; the method of flaw identification; how the flaw was evaluated for acceptability coming out of the spring of 2021 RFO; the flaw size, orientation, and location within the RPV wall; and, whether the above information would be included in the planned alternative request submittal. The licensee responded that the flaw was identified during Code-required vessel ultrasonic exams, that the flaw was evaluated as acceptable per ASME Code,Section XI, Subsection IWB-3600, and that fatigue crack growth analysis concluded that the flaw would not reach the maximum allowable depth for more than 70 years. The licensee responded that the subsurface vertical (axial) flaw
size was approximately 3.8 inches long, with a half-depth of 1.6 inches. The licensee also responded in the affirmative regarding providing further details and inclusion of the above information in the planned submittal. The NRC staff also queried how the flaw would be further evaluated to support the request and whether the submittal would be supplemented with this additional information. The licensee responded that the flaw would be further evaluated, and plans were in place to provide supplemental information to the NRC when complete.
No comments or public meeting feedback were received. No regulatory decisions were made at this meeting.
Please direct any inquiries to me at 301-415-0272, or Lucas.Haeg@nrc.gov.
/RA/
Lucas Haeg, Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-260
Enclosure:
List of Attendees cc w/ enclosure: Listserv
LIST OF ATTENDEES
SUMMARY
OF SEPTEMBER 27, 2021, MEETING WITH TENNESSEE VALLEY AUTHORITY RELATED TO A PLANNED ALTERNATIVE REQUEST PER AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) CODE CASE N-526, ALTERNATIVE REQUIREMENTS FOR SUCCESSIVE INSPECTIONS OF CLASS 1 AND 2 VESSELS, SECTION XI, DIVISION 1, FOR BROWNS FERRY NUCLEAR PLANT, UNIT 2. (EPID L-2021-LRM-0091)
U.S. Nuclear Regulatory Commission Michael Wentzel Lucas Haeg John Tsao Dan Widrevitz Tennessee Valley Authority Tracy Orf Adam Keyser Spencer Craig Members of the Public None Enclosure
ML21273A192 OFFICE NRR/DORL/LPL2-2/PM NRR/DORL/LPL2-2/LA NRR/DNRL/NVIB/BC NAME LHaeg RButler ABuford DATE 9/30/2021 10/6/2021 10/7/2021 OFFICE NRR/DORL/LPL2-2/BC NRR/DORL/LPL2-2/PM NAME DWrona MWentzel DATE 10/7/2021 10/12/2021