ML21033B107

NRR E-mail Capture - RAI - Vogtle Unit 1 - SG Report (L-2020-LRO-0059)

ML21033B107
Person / Time
Site:	Vogtle
Issue date:	02/02/2021
From:	John Lamb NRC/NRR/DORL/LPL2-1
To:	Lowery K Southern Nuclear Operating Co
References
L-2020-LRO-0059
Download: ML21033B107 (3)

Text

From: Lamb, John Sent: Tuesday, February 2, 2021 2:21 PM To: Lowery, Ken G.

Subject:

RAI - Vogtle Unit 1 - SG Report (L-2020-LRO-0059)

Importance: High

Ken, By letter dated September 17, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20262G974), Southern Nuclear Operating Company (SNC, the licensee) submitted information summarizing the results of the spring 2020 steam generator (SG) inspections performed at Vogtle Electric Generating Plant (Vogtle), Unit 1. The inspections were performed during refueling outage (RFO) 22 (1R22).

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 reactor coolant pressure boundary (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 American Society of Mechanical Engineers Boiler and Pressure Vessel Code. All primary 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. Vogtle, Unit 1, TS 5.6.10 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 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, the U.S. Nuclear Regulatory Commission (NRC) staff requests the below additional information.

On January 26, 2021, the NRC staff provided draft request for additional information (RAI) questions to SNC to make sure that the RAIs are understandable, the regulatory basis is clear, to ensure there is no proprietary information, and to determine if the information was previously docketed. On January 29, 2021, SNC requested a clarifying call with the NRC staff. On February 2, 2021, a clarifying call between the NRC staff and the SNC staff was held. SNC stated that SNC would provide the RAI response within 30 days of the date of this email.

If you have any questions, you can contact me at 301-415-3100.

Sincerely, John REQUEST FOR ADDITIONAL INFORMATION By letter dated September 17, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20262G974), Southern Nuclear Operating Company (SNC, the licensee) submitted information summarizing the results of the spring 2020 steam generator (SG)

inspections performed at Vogtle Electric Generating Plant (Vogtle), Unit 1. The inspections were performed during refueling outage (RFO) 22 (1R22).

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 reactor coolant pressure boundary (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 American Society of Mechanical Engineers Boiler and Pressure Vessel Code. All primary 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. Vogtle, Unit 1, TS 5.6.10 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 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, the U.S. Nuclear Regulatory Commission (NRC) staff requests the following additional information:

1. A new foreign object (FO) indication in tube Row 1, Column 2 (R1C2) was identified during RFO 1R22 (spring 2020). The spring 2020 SG tube inspection report (SGTIR) stated that lookback showed a precursor signal for the FO indication in tube R1C2.

a. The report does not indicate in which outage, or in how many outages, the precursor signal was present. Please provide this information.

b. Tube R1C2 was not plugged during 1R22. The spring 2020 SGTIR stated that no secondary side activities were performed during 1R22. Please discuss SNCs decision not to perform FO search and retrieval to confirm the presence of the FO and to attempt to remove it.

2. Table 8 in the RFO spring 2020 SGTIR includes the two broached tube support plate (TSP) wear indications identified during 1R22. Both broached TSP wear indications were first identified during RFO 1R21 (fall 2018). The broached TSP wear indication in tube R44C21 was reported to be in SG-4 in the RFO spring 2020 SGTIR, but it was reported to be in SG-1 in the RFO fall 2018 SGTIR (ADAMS Accession No. ML19080A329). Please confirm the SG in which the broached TSP wear indication in tube R44C21 is located.

Hearing Identifier: NRR_DRMA Email Number: 999 Mail Envelope Properties (DM6PR09MB567157FA8E524E1CF6F828D9FAB59)

Subject:

RAI - Vogtle Unit 1 - SG Report (L-2020-LRO-0059)

Sent Date: 2/2/2021 2:20:49 PM Received Date: 2/2/2021 2:20:49 PM From: Lamb, John Created By: John.Lamb@nrc.gov Recipients:

"Lowery, Ken G." <KGLOWERY@southernco.com>

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