SVPLTR 20-0053, Deviation from BWR Vessel and Internals Project (BWRVIP) Guideline - Inspection of Unit 3 Top Guide Rim Weld

Deviation from BWR Vessel and Internals Project (BWRVIP) Guideline - Inspection of Unit 3 Top Guide Rim Weld

ML20304A208
Person / Time
Site:	Dresden
Issue date:	10/15/2020
From:	Karaba P Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SVPLTR 20-0053
Download: ML20304A208 (2)

Text

Dresden Nuclear Power Station 6500 North D1esden Road Exelon Generation~ Moms, [L 60450 SVPLTR: # 20-0053 October 15 1 2020 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Unit 2 and Unit 3 Renewed Facility Operating License Nos. DPR-19 and DPR-25 NRC Docket Nos. 50-237 and 50-249 Subject. Deviation from BWR Vessel and Internals Project (BWRVIP) Guideline -

Inspection of Unit 3 Top Guide Rim Weld

Reference:

1) BWRVIP-26-A: BWR Vessel and Internals Project, BWR Top.Gu,ide Inspection and Flaw Evaluation Guidelines, EPRI, Palo Alto, CA: 2004. 1009946.

2) BWRVIP-94NP Revision 3: BWR Vessel and Internals Project, BWR Vessel and Internals Project, Program Implementation Guide. EPRI, Palo Alto, CA:

2018. 3002013101.

Exelon Generation Company, LLC (EGC) is a member of the BWR Vessel and Internals Project (BWRVIP) and has committed to implementing BWRVIP products and to providing timely notification to the NRC staff if an applicable aspect of a BWRVIP product will not be implemented.

• BWRVIP-26-A (Reference 1) requires an EVT-1 inspection every other cycle of the top guide rim weld locations accessible during normal refueling activities.

Due to the current plan to permanently shut down both Dresden Units in 2021 and staffing concerns associated with Covid-19, Exelon evaluated opportunities to reduce the work performed during the D3R26 refueling outage. D3R26 is scheduled to start October 2Et 2020.

The Unit 3 rim weld was last inspected in D3R24 and deferring the inspection until D3R27

• (2022) would exceed tlie BWRVIP-26-A (Reference 1) inspection frequency by one cycle.

A Deviation Disposition was prepared in accordance with BWRVIP-94NP, Revision 3 (Reference 2). The Deviation Disposition contains an evaluation documenting the acceptability of n'ot performing the "needed" Top Guide rim weld inspections. The deviation was found to be acceptable because previous evaluations and analysis of the rim weld proved it to be very flaw tolerant. An engineering evaluation has shown that.only.8.9 inches of weld (of a total 600 inches) are needed to ensure structural integrity. Recent inspections resulted in no relevant indications and the amount of weld inspected greatly exceeds the required ligament.

Since the weld is shown to be very flaw tolerant and there 1s no history of cracking, the risk impact. of performing a one-time change to the inspection frequency from two to three cycles is negligible.

• This letter is being transmitted for your information in accordance with Section 3.5 of BWRVIP-94NP Revision 3 {Reference 2). This letter is to notify the NRC of the deviation from "neededD BWRVIP guidance. No actions or approvals on the part of the NRC are required as a result of his letter.

There are no regulatory commitments contained in this letter. Should you have any questions, please contact Joshua Sarrafian 779-231-1376.

Peter J. Karaba Site Vice President Dresden Nuclear Power Station