ML21335A225

NRR E-mail Capture - Catawba Nuclear Station, Unit 2 - Request for Additional Information Spring 2021 Steam Generator Tube Inspection Report (L-2021-LRO-0043)

ML21335A225
Person / Time
Site:	Catawba
Issue date:	12/01/2021
From:	Stone Z NRC/NRR/DORL/LPL2-1
To:	Grzeck L Duke Energy Carolinas
References
L-2021-LRO-0043
Download: ML21335A225 (4)

Text

From: Stone, Zackary Sent: Wednesday, December 1, 2021 11:38 AM To: Grzeck, Lee Cc: Edwards, Nicole D

Subject:

Catawba Nuclear Station, Unit 2 - Request for Additional Information RE:

Spring 2021 Steam Generator Tube Inspection Report (L-2021-LRO-0043)

Attachments: Catawba Unit 2 SG Inspection Report RAIs.docx

Dear Mr. Grzeck,

By letter dated August 2, 2021, Duke Energy Carolinas, LLC, submitted information summarizing the results of the spring 2021 steam generator inspections performed at Catawba Nuclear Station, Unit 2 for the end-of-cycle 24.

The U.S. Nuclear Regulatory Commission staff has determined that additional information is needed as provided in the attached.

Please respond within 30 days of the date of this e-mail.

If you have any questions, please contact me at 301-415-0615 or via e-mail at Zackary.Stone@nrc.gov.

Sincerely, Zackary Stone, Project Manager Plant Licensing Branch, II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No: 50-414 cc w/encl: Listserv

Hearing Identifier: NRR_DRMA Email Number: 1440 Mail Envelope Properties (SA1PR09MB8687AF4930D255F9C5C6B7E0E1689)

Subject:

Catawba Nuclear Station, Unit 2 - Request for Additional Information RE: Spring 2021 Steam Generator Tube Inspection Report (L-2021-LRO-0043)

Sent Date: 12/1/2021 11:37:47 AM Received Date: 12/1/2021 11:37:00 AM From: Stone, Zackary Created By: Zackary.Stone@nrc.gov Recipients:

"Edwards, Nicole D" <Nicole.Edwards@duke-energy.com>

Tracking Status: None "Grzeck, Lee" <Lee.Grzeck@duke-energy.com>

Tracking Status: None Post Office: SA1PR09MB8687.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 823 12/1/2021 11:37:00 AM Catawba Unit 2 SG Inspection Report RAIs.docx 27042 Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

REQUEST FOR ADDITIONAL INFORMATION SPRING 2021 STEAM GENERATOR TUBE INSPECTION REPORT DUKE ENERGY CAROLINAS CATAWBA NUCLEAR STATION, UNIT 2 DOCKET NUMBER 50-414 EPID: L-2021-LRO-0043 By letter dated August 2, 2021 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML21214A160), Duke Energy Carolinas, LLC (the licensee), submitted information summarizing the results of the spring 2021 steam generator (SG) inspections performed at Catawba Nuclear Station, Unit 2 (Catawba Unit 2) for the end-of-cycle (EOC) 24.

In addition, the U.S. Nuclear Regulatory Commission (NRC) staff held a conference call with the licensee on April 12, 2021, regarding the ongoing SG inspection activities at Catawba Unit 2. A summary of the conference call, regarding the spring 2021 SG inspections, is available at ADAMS Accession No. ML21133A004.

Title 10 of the Code of Federal Regulations Part 50.36 establishes the requirements for pressurized water reactors to have technical specifications (TS) which include a SG program with specific criteria for the structural and leakage integrity, repair, and inspection of SG tubes.

Catawba Unit 2 TS Section 5.6.8 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 5.5.9, which requires that a SG Program be established and implemented to ensure SG tube integrity is maintained.

To complete its review of the inspection report, the NRC staff requests the following additional information:

RAI No. 1 The tube in Row 36, Column 100 (R36C100) was plugged in SG 2D at the EOC-24 due to FO

[foreign object] wear at AVB [Anti-Vibration Bar] 3 at 43 %TW [percent through-wall]. The April 12, 2021, conference call summary stated that FO wear was identified at an AVB wear indication, which is not typical, although there was no loose part detected during the outage.

However, the NRC staff notes that the fall 2019 inspection report, dated December 19, 2019 (ADAMS Accession No. ML19353A416), reported a 38 %TW wear indication in tube R36C100 at AVB 3. It appears that the 38 %TW AVB wear indication reported at EOC-23 was reclassified as a FO wear indication at EOC-24. Please discuss the differences between inspections performed at EOC-23 and EOC-24 and the basis for reclassifying the AVB wear indication as a FO wear indication.

RAI No. 2 There appears to be errors in the reported number of tubes plugged in SG 2B prior to the EOC-24 and the total number of tubes plugged in SG 2B after the EOC-24. The spring 2021 inspection report states that 133 tubes were plugged in SG 2B prior to EOC-24 and 7 tubes were plugged during EOC-24, resulting in a total of 140 (133 + 7 = 140) tubes plugged in SG 2B. However, the spring 2021 inspection report also states that a total of 141 tubes have been plugged in SG 2B. The NRC staff notes that the fall 2019 inspection report stated that 131 tubes were plugged in SG 2B prior to EOC-23 and 3 tubes were plugged during EOC-23, resulting in a total of 134 (131 + 3 = 134) tubes plugged in SG 2B. However, the fall 2019

inspection report states that a total of 133 tubes were plugged in SG 2B. Please confirm the total number of tubes plugged in SG 2B.