ML23041A002

NRR E-mail Capture - Request for Additional Information Related to TVA Alternative Request BFN-0-ISI-32 (CNL-22-025)

ML23041A002
Person / Time
Site:	Browns Ferry
Issue date:	02/09/2023
From:	Kimberly Green NRC/NRR/DORL/LPL2-2
To:	Eckermann J Tennessee Valley Authority
References
L-2022-LLR-0062, CNL-22-025
Download: ML23041A002 (7)

Text

From: Kimberly Green Sent: Thursday, February 9, 2023 11:04 AM To: Eckermann, Jeremy Beau

Subject:

Request for Additional Information Related to TVA Alternative Request BFN-0-ISI-32 (CNL-22-025) (EPID L-2022-LLR-0062)

Attachments: Final RAI - BFN SLC Nozzle Alternative Request BFN-0-ISI-32.pdf

Dear Mr. Eckermann,

By letter dated August 22, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22234A271), the Tennessee Valley Authority (TVA), requested an alternative (BFN-0-ISI-32) to certain requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) at Browns Ferry Nuclear Plant (Browns Ferry or BFN), Units 1, 2, and 3, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(z)(2). Specifically, TVA proposed to perform a VT-2 visual examination of the inner radius of the standby liquid control (SLC) nozzle attached to the reactor vessel as part of system leakage testing during plant startup in lieu of the ASME Code required ultrasonic examination for the remainder of the third, fifth, and fourth inservice inspection (ISI) intervals at Browns Ferry, Units 1, 2, and 3, respectively.

The U.S. Nuclear Regulatory Commission (NRC) staff is reviewing the submittal and has identified areas where additional information is needed to complete its review. A draft request for additional information (RAI) was previously transmitted to you by email dated January 25, 2023. At TVAs request, a clarification call was held on February 9, 2023, to clarify the NRC staffs draft RAI. As a result of the clarification call and further NRC deliberation, the staff determined that RAI 1.(e) could be eliminated because sufficient information exists in the request. Additionally, the staff edited the RAIs, as shown below in redline/strikeout, to clarify the staffs requests. The attached RAI reflects these changes.

RAI 1

Issue Section IV states that all three BFN units did not inspect the SLC nozzle inner radii in the first 10-year ISI interval.Section IV also states that with the exception of the BFN Unit 2 second 10-year ISI interval for which relief was requested, ultrasonic examination results have been obtained as required for each successive interval. However, the alternative request is not clear which BFN units have performed what type of examinations and the results of these examinations.

Request Discuss whether any repairs have been made to SLC N-10 nozzles inner radii at BFN Units 1, 2, and 3. If so, provide the following:

(a) a brief description of the repair.

(b) discuss how the degradation of the SLC nozzle was detected.

(c) discuss whether extent of condition inspections were performed.

(d) discuss whether the known degradation will affect the adequacy of the proposed alternative of not performing the required volumetric examination of the SLC nozzle inner radius.

(e) describe the examination history of the SLC nozzle radii, including all 10-year ISI intervals, the examination method used, the examination coverage obtained, and examination results at Browns Ferry Units 1, 2, and 3.

RAI 2

Issue The alternative request states that performing an ultrasonic examination of the SLC nozzle inner radius location would constitute a hardship or unusual difficulty without a compensating increase in quality or safety.Section IV of the alternative request states that the SLC nozzle is located in the bottom head of the vessel, in an area that is inaccessible without extensive disassembly, hindering the ability to complete the Code required volumetric or approved Code alternative VT-1 examinations from the inside surface of the reactor pressure vessel (RPV). The NRC staff notes that ASME Code Case N-648-1 allows a VT-1 visual examination in lieu of an ultrasonic examination but does not specify the VT-1 examination to be performed from the inside surface or outside surface of the SLC nozzle. The alternative request did not address the potential for performing the VT-1 examination on the outside surface of the SLC nozzle.

Request Describe the feasibility of performing the VT-1 examination on the outside surface of the SLC nozzle. If it is not feasible to perform the VT-1 examination on the outside surface of the SLC nozzle, provide a justification Provide additional information regarding the inaccessibility and disassembly of equipment that constitutes the hardship or difficulty for performing the VT-1 from the inside surface.

RAI 3

Request (a) Discuss State whether the system leakage test and associated VT-2 examination will be performed in accordance with (1) Table IWB-2500-1, Examination Category B-P, Item Number B15.10 and B15.20, and (2) IWA-5000 and IWB-5220 of the ASME Code,Section XI.

The remainder of the draft RAI was not changed.

A response to the attached RAI is requested no later than 30 days from 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 at Kimberly.Green@nrc.gov.

Sincerely,

Kimberly Green, Sr. Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Hearing Identifier: NRR_DRMA Email Number: 1944 Mail Envelope Properties (DM6PR09MB5462D05B56D19FD2CE2310088FD99)

Subject:

Request for Additional Information Related to TVA Alternative Request BFN-0-ISI-32 (CNL-22-025) (EPID L-2022-LLR-0062)

Sent Date: 2/9/2023 11:04:20 AM Received Date: 2/9/2023 11:04:00 AM From: Kimberly Green Created By: Kimberly.Green@nrc.gov Recipients:

"Eckermann, Jeremy Beau" <jbeckermann@tva.gov>

Tracking Status: None Post Office: DM6PR09MB5462.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 5206 2/9/2023 11:04:00 AM Final RAI - BFN SLC Nozzle Alternative Request BFN-0-ISI-32.pdf 117168 Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

REQUEST FOR ALTERNATIVE BFN-0-ISI-32 REGARDING AMERICAN SOCIETY OFMECHANICAL ENGINEERS, BOILER AND PRESSURE VESSEL CODE, SECTION XI EXAMINATION REQUIREMENTS FOR CLASS 1 NOZZLE INNER RADII DRAFT REQUEST FOR ADDITIONAL INFORMATION BROWNS FERRY NUCLEAR PLANT UNITS 1, 2, AND 3 DOCKET NOS. 50-259, 50-260, AND 50-296 By letter dated August 22, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22234A271), Tennessee Valley Authority (TVA), requested an alternative to certain requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) at Browns Ferry Nuclear Plant (Browns Ferry or BFN),

Units 1, 2, and 3, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(z)(2). TVA proposed to perform a VT-2 visual examination of the inner radius of the standby liquid control (SLC) nozzle attached to the reactor vessel as part of system leakage testing during plant startup in lieu of the ASME Code required ultrasonic examination for the remainder of the third, fifth, and fourth inservice inspection (ISI) intervals at Browns Ferry, Units 1, 2, and 3, respectively, which are scheduled to end on January 31, 2026.

The NRC staff requests additional information (RAI) to complete its review of the alternative request.

Regulatory Basis The regulations at 10 CFR 50.55a(g), Preservice and inservice inspection requirements, require, in part, that the inservice inspection (ISI) of ASME Code Class 1, 2, and 3 components be performed in accordance with Section XI of the ASME Code and applicable edition and addenda.

Pursuant to 10 CFR 50.55a(g)(4), Inservice inspection standards requirement for operating plants, ASME Code Class 1, 2, and 3 components (including supports) must meet the requirements, except the design and access provisions and the preservice examination requirements set forth in the ASME Code,Section XI to the extent practical within the limitations of design, geometry, and materials of construction of the components. The regulations require that inservice examination of components and system pressure tests conducted during the first 10-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(a)(1)(ii),

ASME Boiler and Pressure Vessel Code,Section XI, 18 months prior to the start of the 120-month interval, subject to the conditions listed in 10 CFR 50.55a(b)(2), Conditions on ASME BPV Code,Section XI.

Pursuant to 10 CFR 50.55a(z), Alternatives to codes and standards requirements, alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC if (1) the proposed alternatives would provide an acceptable level of quality and safety or (2) compliance

2 with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality or safety.

RAI 1

Issue Section IV of the alternative request states that No leakage from this nozzle inner radius has ever been observed on any unit at BFN However, this statement does not preclude the possibility that repairs have been made to the SLC nozzles.

Section IV states that all three BFN units did not inspect the SLC nozzle inner radii in the first 10-year ISI interval.Section IV also states that with the exception of the BFN Unit 2 second 10-year ISI interval for which relief was requested, ultrasonic examination results have been obtained as required for each successive interval.

Request Discuss whether any repairs have been made to SLC N-10 nozzle inner radii at BFN Units 1, 2, and 3. If so, provide the following:

(a) a brief description of the repair.

(b) discuss how the degradation of the SLC nozzle was detected.

(c) discuss whether extent of condition inspections were performed.

(d) discuss whether the known degradation will affect the adequacy of the proposed alternative of not performing the required volumetric examination of the SLC nozzle inner radius.

RAI 2

Issue The alternative request states that performing an ultrasonic examination of the SLC nozzle inner radius location would constitute a hardship or unusual difficulty without a compensating increase in quality or safety.Section IV of the alternative request states that the SLC nozzle is located in the bottom head of the vessel, in an area that is inaccessible without extensive disassembly, hindering the ability to complete the Code required volumetric or approved Code alternative VT-1 examinations from the inside surface of the reactor pressure vessel (RPV).

Request Provide additional information regarding the inaccessibility and disassembly of equipment that constitutes the hardship or difficulty for performing the VT-1 from the inside surface.

RAI 3

Issue Section V of the alternative request states that BFN Units 1, 2, and 3 will perform a VT-2 visual examination of the subject SLC nozzles each refueling outage in conjunction with the Class 1 system leakage test. The alternative request did not describe in detail how the VT-2 examination will be conducted nor the specific ASME Code,Section XI requirements. This

3 information is relevant to the staffs review of the alternative request because it allows the staff to determine the adequacy of the VT-2 examination in lieu of the required ultrasonic examination.

Request (a) State whether the system leakage test and associated VT-2 examination will be performed in accordance with (1) Table IWB-2500-1, Examination Category B-P, Item Number B15.10 and B15.20, and (2) IWA-5000 and IWB-5220 of the ASME Code,Section XI.

(b) Discuss whether the insulation will be removed from the SLC nozzle area prior to the VT-2 examination. If the insulation will not be removed, discuss how the leakage from the SLC nozzle could be detected.

(c) Discuss how the potential leakage from the SLC nozzle can be differentiated from other nozzle leakage if leakage occurs.