NL-23-0068, Responses to NRC Request for Additional Information Related to the Refueling Outage 2R22 Steam Generator Tube Inspection Report

Responses to NRC Request for Additional Information Related to the Refueling Outage 2R22 Steam Generator Tube Inspection Report

ML23027A093
Person / Time
Site:	Vogtle
Issue date:	01/27/2023
From:	Gayheart C Southern Nuclear Operating Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
NL-23-0068
Download: ML23027A093 (1)

Text

Regulatory Affairs 3535 Colonnade Parkway Birmingham, AL 35243 205 992 5000



January 27, 2023 Docket No.: 50-425 NL-23-0068 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Vogtle Electric Generating Plant - Unit 2 Responses to NRC Request for Additional Information Related to the Refueling Outage 2R22 Steam Generator Tube Inspection Report Ladies and Gentlemen:

By letter dated September 30, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22273A160) Southern Nuclear Operating Company (SNC) submitted the Vogtle Electric Generating Plant, Unit 2 Refueling Outage 2R22 Steam Generator Tube Inspection Report, in accordance with the requirements of Vogtle Electric Generating Plant Technical Specification 5.6.10.

After reviewing the report, the NRC notified SNC that additional information is needed for the staff to perform their review. On December 13, 2022, a clarifying call was held to ensure the regulatory basis was clear, to ensure there is no proprietary information, and to determine if the information was previously docketed. During this meeting SNC stated that it would provide an RAI response within 45 days (January 27, 2023).

The Enclosure to this letter provides the SNC responses to the NRC request for additional information (RAI).

This letter contains no NRC commitments. If you have any questions, please contact Amy Chamberlain at 205.992.6361.

Respectfully submitted, Cheryl A. Gayheart Regulatory Affairs Director CAG/dsp/cbg

Enclosure:

SNC Response to Request for Additional Information (RAI) cc: Regional Administrator NRR Project Manager - Vogtle 1 & 2 Senior Resident Inspector - Vogtle 1 & 2 RType: CVC7000

Vogtle Electric Generating Plant - Unit 2 Response to Request for Additional Information Related to the Refueling Outage 2R22 Steam Generator Tube Inspection Report Enclosure SNC Response to Request for Additional Information (RAI)

Enclosure to NL-23-0068 SNC Response to Request for Additional Information (RAI)

Request for Additional Information (RAI)

By letter dated September 30, 2022 (Agencywide Documents Access and Management Systems Accession No. ML22273A160), Southern Nuclear Operating Company, Inc. (SNC, the licensee), submitted information summarizing the results of the spring 2022 steam generator (SG) inspections performed at Vogtle Electric Generating Plant (Vogtle), Unit 2. The inspections were performed during refueling outage (RFO) 22 (2R22). Technical Specification (TS) Section 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 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, the U.S. Nuclear Regulatory Commission (NRC) staff requests the following additional information:

1. Section 2 of the report describes two indications of circumferential outside diameter stress corrosion cracking (ODSCC) detected at the hot-leg top-of-tubesheet (TTS) expansion transition and one indication of axial ODSCC in a dent at a tube support plate (TSP) on the hot leg. The report provides +Point' rotating probe detection and sizing information for each indication. Please provide the following additional information about these indications:

a. Was the circumferential ODSCC at the TTS detected by the array probe?

b. Was the axial ODSCC at the TSP dent detected with the bobbin and array probe?

2. The first full paragraph on page E-10 begins with Mechanical wear at TSP locations, but the last two sentences refer to AVB wear indications. Do the last two sentences refer to TSP wear?

SNC RAI #1 Response 1.a. No, the circumferential ODSCC at the TTS was not detected by the array probe.

1.b. There was a bobbin signal for the axial ODSCC at the TSP that lead to using the +Point probe. The axial ODSCC at the TSP dent was not detected by the array probe.

SNC RAI #2 Response

2. Yes, the last two sentences refer to TSP wear.

E-1