SVPLTR 21-0005, Submittal of Analytical Evaluation of Isolation Condenser Nozzle to Shell Weld Flaw Indications (ISI Weld 3/2/1302A-12/12-8)

Submittal of Analytical Evaluation of Isolation Condenser Nozzle to Shell Weld Flaw Indications (ISI Weld 3/2/1302A-12/12-8)

ML21041A445
Person / Time
Site:	Dresden
Issue date:	01/29/2021
From:	Karaba P Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SVPLTR 21-0005
Download: ML21041A445 (3)

Text

• Exelon Generation Dresden Nuclear Power Station 6500 North Dresden Road Moms, IL 60450 January 29, 2021 SVPLTR 21-0005 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Unit 3 Facility Operating License No. DPR-25 NRC Docket No. 50-249

Subject:

Submittal of Analytical Evaluation of Isolation Condenser Nozzle to Shell Weld Flaw Indications (ISi Weld 3/2/1302A-12/12-8)

In accordance with the American Society of Mechanical Engineers (ASME) Code,Section XI, 2007 Edition with 2008 Addenda, IWC-3134(b) ("Review by Authorities"), Dresden Generating Station, Unit 3, is submitting an analytical evaluation associated with the Isolation Condenser Nozzle to Shell Weld Flaw Indications discovered during the D3R25 refueling outage.

As discussed in the attached report, an analytical evaluation was performed to disposition the indications associated with the isolation condenser inlet nozzle-to-vessel shell weld No.

3/2/1302A-12/12-8. The indications are subsurface, circumferentially oriented. The first flaw is defined as 1.5 inches in length, 0.27 inches deep, 0.82 inches from the outside (OD) surface of the nozzle. The second flaw is defined as 0.75 inches in length, 0.36 inches deep, and 0.82 inches from the OD surface. The evaluation of these flaws was performed in accordance with the acceptance criteria of Appendix A of Section XI.

As concluded in this evaluation, the required safety factors will be maintained until the end of vessel service life (40 additional years) with these indications.

There are no regulatory commitments in this letter.

If you have any questions concerning this letter, please contact Mr. Ryan Sprengel, Regulatory Assurance Manager at (815) 416-2800.

Respectfully,

~

Peter J. Karaba Site Vice President Dresden Nuclear Power Station Page 1 of3

Evaluation of Isolation Condenser Nozzle to Shell Weld Flaw Indications (ISi Weld 3/2/1302A-12/12-8)

Page 3 of 3

EC 626258, Revision 00 Scope Evaluation of Indications on the Steam Unit 3 Isolation Condenser The scope of this DCR EC was to document, evaluate and accept indications found in ISI weld 3/2/1302A-12/12-8 at the steam inlet nozzle to channel. These indications are unacceptable with respect to the 2007 Edition/2008 Addenda ASME Section XI Table IWC-3511-1. This EC documents, evaluates and accepts these indications and updates Struthers Wells vendor (S445) drawing 66-2-5637D2 as shown below:

This DCR EC adds Note B to Struthers Wells Vendor (S445) Drawing 66-2-5637D2:

NoteB Acceptable indications in Unit 3 East nozzle (from line 3-1302A-12"-A) weld to channel.

Refer to EC 626258.

This DCR EC utilized the methodology within the 2007 Edition/2008 Addenda ASME Section XI IWC and IWB to accept the indications.

The technical justification was performed by Structural Integrity Associates (SIA) in calculation 1801382.301, which is issued through this DCR EC. SIA performed evaluations in EC 368322 (Unit 2) and EC 382190 (Unit 3) for other indications found in Isolation Condenser welds/cladding. As such, in review of Attachment 2 ofHU-AA-1212, the response to all questions/topics were either NIA" or Low. Therefore, per Section 4.3.2.1.A, the T&RM can be exited and the controls and reviews of the DCR and calculation processes are adequate without additional compensatory measures or augmented reviews.