ML23065A091

NRR E-mail Capture - South Texas Project - Draft Supplemental Information Request - Proposed Alternative to the Requirements of the ASME Code

ML23065A091
Person / Time
Site:	South Texas
Issue date:	03/03/2023
From:	Dennis Galvin NRC/NRR/DORL/LPL4
To:	Brost W South Texas
References
L-2023-LLR-0004
Download: ML23065A091 (3)

Text

From: Dennis Galvin Sent: Friday, March 3, 2023 2:26 PM To: Wendy Brost (webrost@stpegs.com)

Cc: Jennifer Dixon-Herrity; Dibbern, Zachary

Subject:

South Texas Project - Draft Supplemental Information Request - Proposed Alternative to the Requirements of the ASME Code (EPID L-2023-LLR-0004)

Attachments: STP RR-ENG-4-06 Tendon Inspection Draft Supplemental Request Enclosure Issued 2023-03-03.pdf

Dear Ms. Brost,

By letter dated February 1, 2023 (ADAMS Accession No. ML23032A484), STP Nuclear Operating Company (STPNOC, the licensee) submitted a proposed alternative to certain American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),

Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, requirements at South Texas Project (STP), Units 1 and 2 pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a, codes and standards, paragraph (z)(1). Specifically, the licensee proposed (1) an alternative frequency for the concrete surface examinations to the requirements of IWL-2410(a) and (2) an alternative frequency for the examinations of unbonded post-tensioning systems to the requirements of IWL-2421(b).

To complete its review, the NRC staff has prepared the attached supplemental information request in DRAFT form. To arrange a clarification call and to discuss the due date, please contact me at (301) 415-6256.

Respectfully, Dennis Galvin Project Manager U.S Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Division of Operating Reactor Licensing Licensing Project Branch 4 301-415-6256 Docket Nos. 50-498 and 50-499

Hearing Identifier: NRR_DRMA Email Number: 1981 Mail Envelope Properties (SA1PR09MB8111456C343E945E293F48E4FBB39)

Subject:

South Texas Project - Draft Supplemental Information Request - Proposed Alternative to the Requirements of the ASME Code (EPID L-2023-LLR-0004)

Sent Date: 3/3/2023 2:25:33 PM Received Date: 3/3/2023 2:25:00 PM From: Dennis Galvin Created By: Dennis.Galvin@nrc.gov Recipients:

"Jennifer Dixon-Herrity" <Jennifer.Dixon-Herrity@nrc.gov>

Tracking Status: None "Dibbern, Zachary" <zedibbern@STPEGS.COM>

Tracking Status: None "Wendy Brost (webrost@stpegs.com)" <webrost@stpegs.com>

Tracking Status: None Post Office: SA1PR09MB8111.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 1249 3/3/2023 2:25:00 PM STP RR-ENG-4-06 Tendon Inspection Draft Supplemental Request Enclosure Issued 2023-03-03.pdf 291907 Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

DRAFT SUPPLEMENTAL INFORMATION NEEDED PROPOSED ALTERNATIVE TO ASME CODE, SECTION XI REQUIREMENTS FOR CONTAINMENT BUILDING INSPECTIONS STP NUCLEAR OPERATING COMPANY SOUTH TEXAS PROJECT, UNITS 1 AND 2 DOCKET NOS. 50498 AND 50499 By letter dated February 1, 2023 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23032A484), STP Nuclear Operating Company (STPNOC, the licensee) submitted a proposed alternative to certain American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, requirements at South Texas Project (STP), Units 1 and 2, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(z)(1), Acceptable level of quality and safety. Specifically, the licensee proposed (1) an alternative frequency for the concrete surface examinations to the requirements of IWL2410(a) and (2) an alternative frequency for the examinations of unbonded post-tensioning systems to the requirements of IWL2421(b).

Regarding the proposed alternative frequency to IWL2410(a), the NRC staff determined that sufficient technical information was not provided to decide on the acceptability of the proposed alternative frequency. IWL2410(a) requires concrete surface examinations on a 5-year frequency. IWL2421(b) requires examinations of unbonded post-tensioning systems on a 10-year frequency for sites with multiple units. The letter dated February 1, 2023, proposes alternative frequencies to both the IWL2410 and IWL2421 examinations. An insufficient technical basis is provided for extending the interval for the concrete surface examinations required by IWL2410, and it is unclear to the NRC staff how the proposed alternative frequency, especially the alternative frequency for concrete surface examinations, would provide an acceptable level of quality and safety, as required by 10 CFR 50.55a(z)(1). Relying on the Structures Monitoring Program inspections is not an adequate basis for extending the frequency of the concrete surface examinations required by the IWL2410(a). In previous similar proposed alternatives, the NRC staff has relied on the 5-year concrete surface examinations to ensure the structural integrity of the concrete and to provide reasonable assurance that the proposed alternative frequency for the examinations of unbonded post-tensioning systems would continue to provide an acceptable level of quality and safety.

Please provide the following information to enable the NRC staff to determine the acceptability of the proposed alternative:

1. A technical basis for extending the interval for the concrete surface examinations required by IWL2410.

2. A technical basis for extending the interval for the examinations of unbonded post-tensioning systems required by IWL2420 if the concrete surface examinations interval required by IWL2410 is also extended.

3. Any applicable precedents for the proposed alternative frequency for concrete surface examinations required by IWL2410.

Enclosure