ML18227A107

Request for Additional Information - Relief Request I5R-06

ML18227A107
Person / Time
Site:	Peach Bottom
Issue date:	08/15/2018
From:	Jennifer Tobin Plant Licensing Branch 1
To:	David Helker Exelon Nuclear
Tobin J, NRR/DORL/LPL1, 415-2328
References
EPID L-2017-LLR-0059
Download: ML18227A107 (2)

Text

From: Tobin, Jennifer To: "Helker, David P:(GenCo-Nuc)"

Cc: "Gropp Jr, Richard W:(GenCo-Nuc)"; "Loomis, Thomas R:(GenCo-Nuc)"

Subject:

Peach Bottom Units 2 and 3 - Request for Additional Information - Relief Request I5R-06 (EPID L-2017-LLR-0059)

Date: Wednesday, August 15, 2018 10:54:00 AM Attachments: PB I5R06 RAI.docx

Dear Mr. Helker,

By letter dated April 19, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18109A116), Exelon Generation Company, LLC (the licensee) requested relief from the requirements of the American Society of the Mechanical Engineers (ASME) Boiler and Pressure Vessel (BPV) Code for Peach Bottom Atomic Power Station, Units 2 and 3. The licensee proposed alternative, I5R-06, requests to eliminate the volumetric examination of the reactor pressure vessel (RPV) threads in flange (i.e., Category B-G-1 examinations) during the fifth inservice inspection (ISI) interval at Peach Bottom, Units 2 and 3. Pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Part 50.55a(z)(1), the licensee requested to use the proposed alternative on the basis that the alternative provides an acceptable level of quality and safety.

The Nuclear Regulatory Commissions (NRC) staff is reviewing your submittal and has determined that additional information is needed to complete its review. The specific request for additional information (RAI) questions are provided below. A clarification phone call will be held if needed. A response to these RAIs is requested by September 14, 2018.

If you have any questions, please contact me at (301) 415-2328. A copy of this e-mail will be made publicly available in ADAMS.

Thanks, Jenny Jenny Tobin Project Manager NRR/DORL/LPL-1 Office O9-C12 Phone 301-415-2328 REQUEST FOR ADDITIONAL INFORMATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION PROPOSED ALTERNATIVE REQUEST NO. I5R-06 ON THE CONDITION MONITORING OF THE REACTOR PRESSURE VESSEL THREADS IN FLANGE EXELON GENERATION COMPANY, LLC PEACH BOTTOM, UNITS 2 AND 3 DOCKET NOS. 50-277 AND 50-278 EPID: L-2017-LLR-0059 By letter dated April 19, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18109A116), Exelon Generation Company, LLC (the licensee) requested relief from the requirements of the American Society of the Mechanical Engineers (ASME) Boiler and Pressure Vessel (BPV) Code for Peach Bottom Atomic Power Station, Units 2 and 3. The licensee proposed alternative, I5R-06, requests to eliminate the volumetric examination of the reactor pressure vessel (RPV) threads in flange (i.e., Category B-G-1 examinations) during the fifth inservice inspection (ISI) interval at Peach Bottom, Units 2 and 3. Pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Part 50.55a(z)(1), the licensee requested to use the proposed alternative on the basis that the alternative provides an acceptable level of quality and safety.

The NRC staff has determined that additional information is necessary to complete its review of proposed alternative I5R-06. The NRC staffs request for additional information (RAI) is provided below.

Background:

Section 5 of the licensee proposed alternative states the following:

To protect against non-service related degradation, the Peach Bottom Atomic Power Station, Units 2 and 3 uses detailed procedures for the care and visual inspection of the RPV studs and the threads in flange each time the RPV closure head is removed. These controlled maintenance activities provide further assurance that degradation is detected and mitigated prior to returning the reactor to service.

Historically, the NRC has not authorized the elimination of the RPV threads in flange volumetric inspections for sequential 10-year ISI intervals. Additional information associated with the care and visual inspection activities is needed for the NRC staff to determine if there is reasonable assurance that RPV threads in flange degradation will be detected prior to returning the reactor to service each time the RPV closure head is removed.

Issue:

The licensee proposed alternative lacks sufficient information to justify that degradation of the RPV threads in flange will be detected and mitigated prior to returning the reactor to service each time the RPV closure head is removed during the fifth ISI interval if volumetric inspections are not performed. The licensee has not provided sufficient information about the care and visual inspection activities associated with the RPV closure head removal and installation to justify the elimination of the RPV threads in flange volumetric inspections for a consecutive 10-year ISI interval.

Request:

Address the following plant-specific items for the fifth ISI interval. The plant-specific responses are to consider the impact of stuck studs, missing studs, flange holes with bushings, and other unique flange-stud configurations, as applicable.

1. Provide a detailed description of the care and visual inspections performed on the RPV threads in flange and studs each time the RPV head is removed. Alternatively, provide the procedures that control the care and visual inspection activities.

2. Justify that the existing care and visual inspection activities will provide assurance that degradation of the RPV threads in flange is detected and mitigated prior to returning the reactor to service each time the RPV closure head is removed during the fifth ISI interval if volumetric inspections are not performed.