ML20316A042

NRR E-mail Capture - FW: Draft RAI for North Anna Unit 2 Steam Generator Tube Inspection Report (ML19179A075)

ML20316A042
Person / Time
Site:	North Anna
Issue date:	11/10/2020
From:	Ed Miller NRC/NRR/DORL/LPL2-1
To:	Aitken D Dominion Generation
References
Download: ML20316A042 (4)

Text

From: Miller, Ed Sent: Tuesday, November 10, 2020 4:15 PM To: diane.aitken@dominionenergy.com

Subject:

FW: Draft RAI for North Anna Unit 2 Steam Generator Tube Inspection Report (ML19179A075)

Attachments: NAPS2 SG Inspection Report Draft RAIs.doc

Diane, Attached is the NRC staffs draft RAI for the subject review. The questions are being transmitted to you to determine 1) If the question clearly conveys the NRC informational needs, 2) Whether the regulatory basis for the question is clear, and 3) If the information has already been provided in existing docketed correspondence. Additionally, review of the draft question will allow you to determine whether you are able to support a 30 day response time. Thank you.

Ed Miller (301) 415-2481

Hearing Identifier: NRR_DRMA Email Number: 884 Mail Envelope Properties (SA9PR09MB55498E3E0145EB75AAF79623E9E90)

Subject:

FW: Draft RAI for North Anna Unit 2 Steam Generator Tube Inspection Report (ML19179A075)

Sent Date: 11/10/2020 4:15:04 PM Received Date: 11/10/2020 4:15:04 PM From: Miller, Ed Created By: Ed.Miller@nrc.gov Recipients:

"diane.aitken@dominionenergy.com" <diane.aitken@dominionenergy.com>

Tracking Status: None Post Office: SA9PR09MB5549.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 511 11/10/2020 4:15:04 PM NAPS2 SG Inspection Report Draft RAIs.doc 44440 Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

DRAFT REQUEST FOR ADDITIONAL INFORMATION OFFICE OF NUCLEAR REACTOR REGULATION Issue Date: 11/10/2020 North Anna Unit 2 Steam Generator Inspection Report Review Virginia Electric & Power Co.

Dockets: 05000339-PWR-North Anna 2 EPIDS: L-2019-LRO-0108 Questions Question Number: 75 By letter dated June 24, 2019 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19179A075), Virginia Electric and Power Company submitted information summarizing the results of the spring 2019 steam generator (SG) inspections performed at North Anna Power Station, Unit 2. The inspections were performed during refueling outage 26.

In Appendix A of Part 50 of Title 10 of the Code of Federal Regulations (10 CFR), General Design Criteria (GDC) 14, 15, 30, 31, and 32, define requirements for the structural and leakage integrity of the RCPB. As part of the RCPB, the SG tubes must also meet the requirements of 10 CFR 50.55a with respect to inspection and repair requirements of the ASME Code. All pressurized water reactors have Technical Specifications (TS) according to 10 CFR 50.36 that include a SG Program with specific criteria for the structural and leakage integrity, repair, and inspection of SG tubes. North Anna Power Station, Unit 2 TS Section 5.6.7 requires that a report be submitted within 180 days after the initial entry into hot shutdown (MODE 4) following completion of an inspection of the SGs performed in accordance with TS Section 5.5.8.d, which requires that a SG Program be established and implemented to ensure SG tube integrity is maintained.

To complete its review of the inspection, the U.S. Nuclear Regulatory Commission (NRC) staff requests the following additional information:

1. Please discuss the results of the primary side channel head visual examinations performed on each SG (i.e.,

plugs, divider plate, and bowls).

Question Number: 76

2. The NRC staff has the following questions regarding Table 1, "Bobbin Probe Indication/Special Interest Exam Summary," in the spring 2019 SG inspection report:

a. Eighteen tubes with 19 hot-leg (HL) manufacturing burnish marks (MBHs) in SG B were reported in the spring 11/10/2020 12:42:02 PM

2019 SG tube inspection report. However, 19 tubes with 20 HL MBHs in SG B were reported in the fall 2014 SG tube inspection report (ADAMS Accession No. ML15050A040). Given that no tubes have been plugged in this steam generator, please discuss the difference in the number of tubes and MBHs between the two inspection reports.

b. In SG C, 605 tubes with 1,002 cold-leg (CL) overexpansions (OXPs) were reported in the spring 2019 SG tube inspection report. However, the spring 2016 SG inspection report reported 603 tubes with 998 CL OXPs in SG C (ADAMS Accession No. ML16202A066). Please confirm that 2 tubes with 4 CL OXPs were newly identified during the spring 2019 SG inspections. In addition, please provide any insight you may have with regards to these CL OXPs being newly identified during the spring 2019 SG inspections.

c. Two tubes with no tube expansion in SG C were reported in the spring 2019 SG tube inspection report.

However, the spring 2016 SG tube inspection report reported one tube with no tube expansion in SG C. Please confirm that an additional tube with no tube expansion in SG C was identified during the spring 2019 SG inspections. In addition, please provide any insight you may have with regards to this no tube expansion being newly identified during the spring 2019 SG inspections.

11/10/2020 12:42:02 PM